EETP: "European Emission Test Programme" Final report

Transcription

INSTITUT FRANÇAIS DU PETROLE
Techniques d'Applications Energétiques
Fevrier 2004
Objectif: Moteurs-Energie
N° de projet: L215
N° d’étude: L215002
Niveau de confidentialité: 3
Nombre d’exemplaires: 30
CONFIDENTIEL
EETP: "European Emission Test Programme"
Final report
N.JEULAND – X. MONTAGNE (RL50)
Summary
Fuels and engines used in road transportation have to face two main challenges in a highly
competitive economy:
• the reduction of pollutant emission levels to such values that air quality in cities complies with
World Health Organisation standards
• the reduction of carbon dioxide emissions (CO2), considered as being the major greenhouse gas
contributing to global warming and climate change.
Among the technical solutions available to face up to these two challenges, the use of automotive
LPG deserved to be further investigated. Indeed, the potential of this gas to reduce CO2 emissions
is important due to its high H/C ratio. Moreover, its simple chemical composition seems a
promising way to reduce the emissions of some significant pollutant.
In order to compare the emission levels of vehicles currently sold in Europe, which run on each of
the three fuels - diesel, petrol or LPG - the programme designed to update data on regulated and
non regulated emissions was developed by the LPG industry and environmental /governmental
bodies, all over Europe and implemented in four laboratories.
This programme also aimed at assessing the relative impact of these fuels on the air quality in terms
of health and greenhouse effects.
A specific test sequence was developed on the basis of the three different driving cycles that are
representative of real-life driving conditions. A large number of vehicles sold in Europe were tested
on a pan-European basis. LPG vehicles were either produced by car manufacturers or postequipped under their control.
All the emissions, environmental index and health effect indicators have been compared between
each fuel, allowing a more accurate comparison of each technology advantages and drawbacks
The main conclusions are:
•
as far as pollutant emissions are concerned, LPG vehicles have significantly lower emissions of
NOx and particulates than diesel vehicles. They also have similar or lower emissions for most
non-regulated pollutants compared to diesel vehicles, especially oxygenated compounds
1
(formaldehyde, acetaldehyde) and benzene (equivalent level LPG / diesel, but significantly
lower for LPG than for petrol).
•
In any event, the CO2 emissions measured for LPG vehicles were much lower than those of
petrol vehicles and were close to those of diesel vehicles. In certain situations (motorway
cycle), some vehicles even have lower CO2 emissions in LPG than in diesel. It could
consequently represent a promising way to contribute to the reduction of CO2 emissions.
•
The environmental and health effect indicators calculated showed that exhaust emissions from
LPG vehicles had lower cancer index (mainly linked to the lower particulate emission level),
acidification potential (due to their lower NOx emission level) and regional ozone forming
potential (TOCP) than diesel vehicles
Some points still remain to be optimised, such as :
•
CO emissions, that remain higher for LPG vehicles
•
HC emissions, which for LPG vehicles are equal compared to petrol on NEDC but slightly
increased on CADC.
•
As far as ozone formation is concerned, the above-mentioned conclusion should be mitigated
when considering the local ozone forming potential (POCP) which is higher for LPG vehicles.
Moreover, in terms of cancer index, the level of LPG and petrol vehicles can be joined by the
diesel ones if equipped with the DPF (Diesel Particulate Filter).
The programme also has shown that LPG engine map tuning is one of the key elements influencing
pollutant emissions.
Consequently, as long as precise ECU calibration is done, LPG vehicles can be seen as a promising
way to further reduce the main pollutant emissions, especially :
NOx,
Particulates (LPG vehicles are however at the level of the most modern diesel technologies
eg: DPF),
Concerning CO and HC it seems that progress can be done with a relevant development on
mapping on ECU.
Mobile Source Air Toxics (MSAT)
while limiting the increase in CO2 emissions.
2
This European Emission Test Programme has been initiated and founded by:
ADEME (Agence De l'Environnement et de la Maîtrise de l'Energie, France)
BP LPG Europe
CFBP (Comité Français du Butane et du Propane, France)
E.S.T (Energy Saving Trust, UK)
LPGA (Liquefied Petroleum Gas Association, UK)
SHELL LPG / Global Autogas
SHV Gas
TOTALGAZ
V.V.G. (Vereniging Vloeibaar Gas , the Netherlands).
The Netherlands Ministry of Spatial Planning, Housing and the Environment (VROM)
3
1
INTRODUCTION.....................................................................................................................................................7
1.1
1.2
1.3
1.4
2
BACKGROUND.........................................................................................................................................................7
AIM OF THE PROGRAMME .......................................................................................................................................9
METHODOLOGY: .....................................................................................................................................................9
RESULTS DISPLAY .................................................................................................................................................10
PROGRAMME DESCRIPTION ..........................................................................................................................10
2.1 SELECTED LABORATORIES ....................................................................................................................................10
2.2 VEHICLE SELECTION: ............................................................................................................................................10
2.3 DRIVING CYCLES: .................................................................................................................................................11
2.3.1
New European driving cycle (NEDC)........................................................................................................11
2.3.2
ARTEMIS (CADC) Cycles..........................................................................................................................12
2.3.3
Warm Start testing......................................................................................................................................14
2.4 FUELS....................................................................................................................................................................14
2.5 MEASUREMENTS ...................................................................................................................................................14
3
RESULTS ................................................................................................................................................................15
3.1 ROUND ROBIN TESTS RESULTS .............................................................................................................................15
3.1.1
Round robin test description ......................................................................................................................15
3.1.2
Results.........................................................................................................................................................15
3.1.3
Conclusion of the round robin tests ...........................................................................................................18
3.2 FULL TEST RESULTS ..............................................................................................................................................19
3.2.1
Regulated emissions ...................................................................................................................................19
3.2.1.1
3.2.1.2
3.2.1.3
3.2.1.4
3.2.2
3.2.3
NOx emissions................................................................................................................................................... 19
CO emissions..................................................................................................................................................... 22
HC emissions..................................................................................................................................................... 27
PM emissions..................................................................................................................................................... 30
CO2 emissions.............................................................................................................................................32
Unregulated Pollutant emissions results ...................................................................................................38
3.2.3.1
3.2.3.2
3.2.3.3
3.2.3.4
3.2.3.5
Oxygenated products ......................................................................................................................................... 38
PAH results........................................................................................................................................................ 41
BTX emissions .................................................................................................................................................. 44
Particle Size ....................................................................................................................................................... 48
NO2 emissions ................................................................................................................................................... 51
3.3 ENVIRONMENTAL IMPACT AND HEALTH EFFECT...................................................................................................55
3.3.1
Ozone (O3) Formation................................................................................................................................55
3.3.2
Cancer risk .................................................................................................................................................57
3.3.3
Acidification ...............................................................................................................................................59
3.3.4
Climate change...........................................................................................................................................61
3.3.4.1
3.3.4.2
Global Warming Potential.................................................................................................................................. 61
Life Cycle Assessment....................................................................................................................................... 63
3.4 COMPARISON WITH ALTERNATIVE TECHNOLOGIES / FUELS ..................................................................................67
3.4.1
Diesel vehicle equipped with DPF .............................................................................................................67
3.4.2
CNG vehicle................................................................................................................................................68
3.4.2.1
3.4.2.2
3.4.2.3
3.4.2.4
3.4.3
Big van........................................................................................................................................................71
3.4.3.1
3.4.3.2
3.4.3.3
4
Background ....................................................................................................................................................... 71
Test results......................................................................................................................................................... 72
Summary ........................................................................................................................................................... 75
SUMMARY OF MAIN RESULTS OBTAINED.................................................................................................76
4.1.1
4.1.2
5
Regulated pollutant emissions............................................................................................................................ 68
CO2 emissions ................................................................................................................................................... 70
Unregulated pollutant emissions ........................................................................................................................ 70
Summary ........................................................................................................................................................... 71
Tables..........................................................................................................................................................76
Diagrams ....................................................................................................................................................77
MAIN CONCLUSION ...........................................................................................................................................79
4
6
REFERENCES........................................................................................................................................................81
7
APPENDICES .........................................................................................................................................................83
7.1 FUEL ANALYSIS.....................................................................................................................................................84
7.2 CURRENT AND FUTURE REGULATIONS .................................................................................................................87
7.3 LIST OF VEHICLES TESTED ....................................................................................................................................88
7.4 TABLES OF NUMERICAL RESULTS..........................................................................................................................89
7.4.1
NOx emissions ............................................................................................................................................89
7.4.2
CO2 emissions.............................................................................................................................................92
7.4.3
CO emissions ..............................................................................................................................................96
7.4.4
HC emissions ..............................................................................................................................................99
7.4.5
PM emissions............................................................................................................................................102
7.4.6
Oxygenated compounds............................................................................................................................106
7.4.7
PAH ..........................................................................................................................................................107
7.4.8
BTX ...........................................................................................................................................................108
7.4.9
NO2 ...........................................................................................................................................................111
7.4.10 Ozone formation .......................................................................................................................................112
7.4.11 Acidification potential ..............................................................................................................................113
7.4.12 Global warming potential ........................................................................................................................113
5
Glossary of abbreviations
ACEA:
BTX:
CADC:
CITEPA:
CNG:
CO:
CO2:
CONCAWE:
CPV:
CVS:
DPF:
ECE cycle:
ECU:
EUCAR:
EETP:
ELPI:
EPA:
EUDC:
GHG:
GM:
GREET:
GWP:
HC:
IARC:
ICRP:
IPCC:
JRC:
MSAT:
NEDC:
NOx:
N2O:
OEHHA:
PAH:
PM:
PM10:
PMP:
POCP:
TOFP:
UDC:
URF:
VOC:
WHO:
Association des Constructeurs Européens d'Automobiles
Benzene Toluene Xylenes
Common Artemis Driving Cycle
Centre Interprofessionel Technique d'Etude de la Pollution Atmosphérique
Compressed Natural Gas
Carbon monoxide
Carbon dioxide
Conservation of Clean Air and Water in Europe (the oil companies' european
association for environment, health and safety in refining and distribution)
Cancer Potency Value
Constant Volume Sampler: dilution system used for exhaust gas sampling and
analysis.
Diesel Particulate Filter
Economic Commission for Europe driving cycle (also called "UDC")
Electronic Control Unit
European Council for Automotive R & D
European Emission Tests Programme
Electric Low Pressure Impactor
Environmental Protection Agency
Extra-Urban Driving Cycle
Green House Gas
General Motors
Greenhouse gases, Regulated Emissions, and Energy use in Transportation
Global Warming Potential
Hydrocarbons
International Agency for Research on Cancer
International Commission on Radiological Protection
Intergovernmental Panel on Climate Change
Joint Research Center (European Comission)
Mobile Source Air Toxics
New European Driving Cycle
Nitrogen oxides: include NO (nitric oxide) and NO2 (nitrogen dioxide)
Nitrous oxide
Office of Environmental Health Hazard Assessment
Poly Aromatic Hydrocarbons
Particulate Mass
Particulate Matter 10µm: mass of particulate with a diameter equal or lower than
10 µm
Particulate Matter Programme: UNECE programme for the study of particulate size
measurement technique for low emission levels
Photochemical Ozone Creation Potentials
Tropospheric Ozone Forming Potentials
Urban Driving Cycle
Unit Risk Factor
Volatile organic compounds
World Health Organization
6
1
Introduction
1.1 Background
In Europe, road transport exhaust emissions account for an important part of all CO2 emissions and
significant emissions of fine particles and nitrogen oxides from any sources (for instance, in France,
28% of CO2 emissions, 54% of NOx emissions and 15% of PM10 – source: CITEPA). Cooperation between the Automotive Industry, the Oil Companies and the European Union (Auto-Oil
1 & 2) produced a framework of regulations leading to considerable reductions in key pollutants
(HC, CO, NOx, PM). Vehicle and fuel technologies have led to a vast improvement in the emission
profile of modern vehicles compared to those produced two decades ago.
3
Petrol &
LPG
2.5
emission (g/km)
Diesel
2
CO
HC
NOx
CO
HC+NOx
NOx
PM
2000
2.3
0.2
0.15
0.64
0.56
0.5
0.05
2005
1
0.1
0.08
0.5
0.3
0.25
0.025
PM
HC
NOx
HC + NOx
CO
1.5
1
0.5
0
1992 1996 2000 2005
1992 1996 2000 2005
Diesel
Petrol / LPG
Figure 1: Variation in European emission limits.
In the meantime, the total number of vehicles has risen sharply, and consequently has minimised
this improvement. Nevertheless, air quality improvements over the last ten years have been
striking:
7
Figure 2: Variation in air quality in Europe since 1990 (source: IFQC)
The search for alternative fuels to replace conventional petrol and diesel, for air quality, climate
change and fuel diversity reasons, led to the development of a large European market for
automotive Liquefied Petroleum Gas (LPG, generally called “autogas”). The Italian, French, UK
and Dutch markets together now account for some 2 million autogas vehicles.
The emissions of these vehicles had already been investigated all over Europe in several research
campaigns. However, with the introduction of Stage 3 emission limits in the year 2000 it became
obvious that more exhaustive data would be required in order to assess the impact on air quality of
the use of autogas compared to conventional fuels, especially diesel.
Recent improvements in diesel and petrol technologies and the growing concern about
environmental issues on a local scale (air quality in the cities) but also global scale (greenhouse
effect, CO2 emissions) have indeed led to the urgent need for a large-scale test programme in order
to update comparative emission levels of LPG, diesel and petrol.
In order to build this database, discussions were held during 2002 and a test programme was
initiated by ADEME, BP LPG Europe, CFBP, E.S.T, LPGA, SHELL LPG / Global Autogas, SHV
Gas, TOTALGAZ, V.V.G and the Dutch Ministry of Environment. It was developed on a panEuropean basis and involved four test houses.
8
1.2 Aim of the programme
The purpose of this test programme was to compare emission levels of vehicles currently sold in
Europe which run on one of the three fuels: diesel, petrol or LPG.
To achieve this, information about emission profiles of vehicles using these fuels was updated and
data on their relative impact on the air quality in terms of health and greenhouse effects was
collected.
In order to compare the air quality implications in the "real world", a specific driving cycle was
used.
1.3 Methodology:
Vehicles:
Vehicles were selected in order to be representative of the car manufacturer’s production, as
vehicles currently available on the European market (passenger car / vans, small / average / big
vehicles…), see section 2.2.
This selection and the number of vehicles tested (30 vehicles) enables reliable processing of the
data.
Laboratories:
Tests were conducted in 4 different test houses, selected among recognised laboratories in the
European Union.
Since different official test houses are involved in the programme, a reference or correlation
between them needed to be established.
Three vehicles were therefore tested in these laboratories for round robin purpose, to ensure the
reproducibility of the measurements.
Tests:
Since vehicles are used in different ways and there are many different traffic conditions (congested
city traffic; extra-urban conditions; motorway use), the tests were performed according to three
cycles. These cycles respected a common sequence in order to ensure reproducibility between test
houses:
• a NEDC, followed by
• a "warm" start cycle based on the NEDC, followed by
• a CADC, with warm start and running conditions closer to "real life" driving.
Measurements were taken during each cycle in order to assess the performances of vehicles in each
driving situation. In addition, where appropriate, each phase of the cycles was measured separately.
Three vehicles were tested by the four laboratories on the NEDC for the purpose of the round-robin
test. They were tested at the same (or nearly the same) mileage by transporting them between tests
in order to avoid any drift due to vehicle mileage.
Finally, a consistent database was established with all the emission test results, thus enabling a
comparison of LPG, petrol and diesel emission levels.
9
1.4 Results display
All the measurement results are presented in appendices (section 7).
Tables and figures showing the most significant results are shown in section 3.
For each emission, the background and commented results are shown, and a summary is proposed.
Conclusions are shown in section 5.
2 Programme description
2.1 Selected laboratories
The participating laboratories were:
TNO (The Netherlands)
MILLBROOK PROVING GROUND (UK)
IFP (France)
RWTÜV (Germany)
2.2 Vehicle selection:
For each of the three fuels, ten models of vehicles were selected. This led to the testing of 30
vehicles.
Nine models are classified in category "M" (passenger cars, according the 70/220 directive) or "N1
< 1760 kg" and one in category "N1 > 1760 kg" (light duty vehicles)
The selected vehicles comply with the following criteria:
- most modern technology available on the European market, on each fuel;
- models developed in a LPG version and marketed as such by the car manufacturer or its
importer, in at least one of the countries concerned by the test programme;
- existing in very similar versions in petrol and diesel (equivalent equipment, same range
of power), allowing customer choice based on the fuel technology only;
- minimum of 5 000 km and maximum of 25 000 km on the odometer;
- at least Euro 3 type approval for each fuel.
The selected LPG vehicles were either manufactured on the production line or post-equipped under
the control of the car manufacturer.
Two vehicles were chosen to evaluate the emission from other fuels (CNG) and after-treatment
strategies (DPF).
The list of vehicles is shown in appendices (section 7.3).
Since the aim of the program was to compare the emission performance of different fuels and not
the performance of either cars or manufacturers, throughout the report vehicles are encoded with a
letter.
10
2.3 Driving cycles:
As underline previously, three cycles were chosen in order to be representative of a wide range of
use.
A common test methodology (Figure 3) was established in order to ensure good repeatability
between the different laboratories.
Cold
Start
Cycle
NEDC
Overnight
cold soak
Down time
20-40 mins
10 min stop
NEDC
Conditioning cycle
CADC
Warm start cycles
- 1st cycle : standard NEDC (New European Driving Cycle),
- 2nd cycle : "warm" NEDC
- 3rd cycle : CADC (Common Artemis Driving Cycle).
Figure 3: test sequence.
The driving cycles are as follows:
2.3.1
New European driving cycle (NEDC)
The NEDC is the current European type approval cycle and it is fully described in European
Directive 70/220/EC (and amendments). Compliance with emission limit classes EURO 3, for
passenger cars and light duty vehicles is checked with this cycle.
It is considered as a "cold" test because the vehicle is conditioned for a sufficient time at 20 to 25°C
(type I test).
The complete type approval test, according to European Directive 70/220/EC, consists of two
different driving patterns, which are driven on a chassis dynamometer in a test laboratory.
The engine is not stopped between the two parts of the test:
•
The urban part (part one, so called ECE).
It simulates urban conditions in a congested area. The average speed is 19 km/h, the
maximum speed is 50 km/h. It is repeated 4 times, takes 780 seconds and the distance
travelled is 4.052 km.
•
The EUDC extra – urban part (part two or EUDC)
this part of the cycle simulates rural conditions and also a motorway run of up to
120 km/h. The average speed is 62.6 km/h and the corresponding time is 400 s.
11
140
EUDC cycle
120
Speed (km/h)
100
ECE cycle
80
60
40
20
0
0
200
400
600
800
1000
1200
time (s)
Figure 4: New European Driving Cycle (NEDC)
For the NEDC, gas sampling begins as soon as the engine is started, while previously (EDC, Euro I
and II before 2000), sampling started after 40 seconds of idling.
The day before the test, the vehicle and the exhaust after treatment equipment are submitted to a
conditioning sequence with the fuel used for the test. Thereafter, the vehicle is conditioned at room
temperature (20 – 25°C) for 12 to 36 hours.
2.3.2
ARTEMIS (CADC) Cycles
These cycles were developed through a statistical analysis of speed profile databases consisting of
90 000 km monitored on board 80 passenger cars in France, Germany, the UK and Greece. They
were supplemented by another 10,000 km obtained in Switzerland and Italy under controlled traffic
conditions. These cycles, called Common Artemis Driving Cycles (CADC) by convention,
correspond to a total of 40 minutes of urban, rural and motorway driving and have been built in
order to be more representative of driving conditions encountered in Europe.
This is subdivided into three different phases covering the driving conditions:
Phase 1: urban conditions (4.43 km, ~ 10% of the total cycle)
Phase 2: road (16.4 km, ~ 37% of the total cycle)
Phase 3: motorway (23.77 km, ~ 53% of the total cycle)
While the emissions were recorded for each phase, the results were consolidated for the global
CADC according to the mileage of each phase.
12
The following figures present the speed profile of the three cycles representing real global driving
conditions and used for vehicle testing. Motorway has two options for high power and low power
vehicles. The 130 km/h option was used in this programme.
Figure 5: CADC phase 1: urban cycle.
Figure 6: CADC phase 2: road cycle.
Figure 7: CADC phase 3: motorway cycle.
13
2.3.3
Warm Start testing
It was decided that the second and the third tests of the sequence should use a warm start in order to
simulate the emission profile of the vehicles in a “parcel delivery” mode and to highlight the
emissions in "stop and go" and more transient conditions.
In order to harmonise these "warming" conditions between the laboratories, an ECE cycle was used
as a preconditioning cycle, followed by a 10-minute stop of the engine before each of these tests.
2.4 Fuels
To avoid the influence of variable fuel composition on emission measurement, each fuel was
supplied from a single source and made available to each laboratory.
The fuels were in compliance with the current European specifications for commercial fuels:
• En 228: 1999: petrol
• En 590: 1999: diesel
• En 589: 2000: LPG, also called "Autogas"
Moreover, future expected specifications were taken into account.
As far as CNG is concerned, since there are no uniform specification standards for Europe, it was
decided to run the tests with a G20 quality (one of the CNG reference fuels of the directive 70/220).
The detailed analysis of these fuels is presented in appendices (section 7.1)
2.5 Measurements
The emissions measured were standard regulated pollutants i.e. carbon monoxide, hydrocarbons,
NOx and particulate mass (for diesels).
Carbon dioxide emissions were also measured.
Fuel consumption was calculated according to a carbon balance.
On the CADC, hydrocarbon speciation was undertaken, as well as other unregulated emissions
such as NH3, NOx speciation and N2O.
Generally the tests were only done once. However, reliability of the tests was assessed using the
results of the round-robin test (see section 3.1).
As regards particulate matter emitted by engines, there is now a growing concern about the size of
these aerosols and the number of particulates. However, nothing is regulated as yet due since there
is no harmonised test method. Different programmes are running world-wide (like the PMP
program from the UN – Geneva) to assess the different techniques available (reliability,
repeatability and reproducibility).
The ELPI (Electric Low Pressure Impactor) technique was chosen. It is commonly used by most
laboratories and many studies have assessed its reliability (European "PARTICULATES"
programme or French part of the UNECE PMP programme for instance).
14
3 Results
3.1 Round Robin tests results
3.1.1
Round robin test description
The consistency of the results of the four laboratories is important for the credibility of the
program.
Therefore, the following conditions need to be fulfilled:
same vehicle tested in different places
same procedures applied for the tests
same fuel provided to the test lab
In order to meet these requirements, three vehicles involved in the program were tested as control
vehicles in three of the four laboratories, using the official type approval NEDC as prescribed in
Chapter 2. Consequently, each laboratory tested at least two control vehicles.
The coastdown times and vehicle inertia were the same in all the laboratories.
3.1.2
Results
Table 1 summarises the results obtained for the regulated emissions: CO, HC, NOx and for CO2.
-
LPG vehicle, big displacement, called "big LPG"
LPG vehicle, medium displacement, called "medium LPG"
Diesel vehicle, called "Diesel"
NOx g/km
"big LPG"
"medium
LPG"
"diesel"
IFP
0.014
0.012
TNO
0.020
0.000
0.380
0.412
0.410
HC g/km
"big LPG"
"medium
LPG"
"diesel"
IFP
0.041
Millbrook
0.034
TNO
0.040
0.030
0.017
0.025
0.010
CO g/km
"big LPG"
"medium
LPG"
"diesel"
IFP
0.488
Millbrook
0.288
TNO
0.490
0.550
0.120
0.050
0.061
Millbrook
TUV
0.017
0.004
mean
0.017
0.005
0.401
TUV
0.029
0.028
mean
0.037
0.031
0.017
TUV
0.465
0.654
mean
0.481
0.497
0.077
15
Std Dev Error (%)
0.003
19%
0.006
129%
0.018
5%
Std Dev Error (%)
0.007
20%
0.003
11%
0.008
49%
Std Dev Error (%)
0.014
3%
0.188
43%
0.038
56%
CO2 g/km
"big LPG"
"medium
LPG"
"diesel"
IFP
205.5
PM g/km
"Diesel"
Millbrook
155.1
TNO
210.7
161.7
129.4
137.2
138.8
IFP
0.028
Millbrook
-
TNO
0.030
TUV
204.7
156.7
mean
207.0
157.8
135.2
TUV
mean
0.029
Std Dev Error (%)
3.281
2%
3.460
2%
5.035
4%
Std Dev Error (%)
0.001
6%
Table 1: Round-robin tests results.
The relative error on NOx appears to be very high for the "medium LPG" vehicle (130% in table 1).
Nevertheless, it must be considered in relation with the very low absolute level of NOx emissions
of this vehicle (5 mg/km), which is close to the detection limit of the method.
The CO2 emission measurements of the laboratories were roughly the same for each control
vehicle, which means that the vehicles were not affected by transport between test facilities.
Together with table 1 above, the figures 8, 9 and 10 also illustrate the reproducibility check.
For each pollutant, a mean value and an "error bar" (calculated according to the 95% confidence
interval) are shown:
0.700
Millbrook
IFP
TNO
Mean
Euro 3
Euro 4
0.600
Emission (g/km)
0.500
0.400
0.300
0.200
0.100
0.000
CO
HC
NOx
HC+NOx
Figure 8: "diesel" vehicle
16
PM
Euro 3 : 2.3 g/km
1.0
TÜV
Millbrook
TNO
Mean
Euro 3
Euro 4
0.9
0.8
emission (g/km)
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
CO
HC
NOx
HC+NOx
Figure 9: "medium LPG" vehicle
Euro 3 : 2.3 g/km
1.0
TÜV
IFP
TNO
Mean
Euro 3
Euro 4
0.9
0.8
emission (g/km)
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
CO
HC
NOx
Figure 10: "big LPG" vehicle.
17
HC+NOx
The three vehicles comply with EURO 3 emission limits. Among them, the two LPG vehicles
already meet EURO 4 limits.
In order to assess these results, the calculated error was compared with the one resulting from
round-robin tests performed each year in France: 15 laboratories tested the same vehicles (diesel
and petrol).
Figure 11 (where results of the French round-robin test are called "Ref Diesel" and "Ref petrol")
shows this comparison.
0.30
"Diesel"
"medium LPG"
"Big LPG"
Ref Diesel
Ref Petrol
Error in measurements
95% confidence intervalle.
0.25
0.20
0.15
0.10
0.05
0.00
CO
HC
NOx
PM
Figure 11: Error comparisons.
This figure shows that the reproducibility obtained for most of the pollutant emissions is good and
in accordance with the uncertainty values measured during routine round-robin tests.
3.1.3
Conclusion of the round robin tests
The round-robin test demonstrates that:
a. The 3 vehicles tested are below the EURO 3 emission limits;
b. The reproducibility of the results obtained for this round robin is comparable to
commonly measured reproducibilities. Therefore, any measurement can be considered
without reference to the laboratory which performed it.
As such, it validates the principle of the test programme.
18
3.2 Full test results
Only graphical results are presented in the following sections, Nevertheless, all the numerical
results can be found in section 7.4.
The results obtained for the nine "category M" models of vehicles (see section 2.2) were included
in the database and were statistically analysed.
The "category N1 > 1760 kg" model (see section 3.2) was considered separately, due to its higher
global pollutant emission level. Conclusions are shown in the section 3.4.3.
The results obtained with the CNG and DPF vehicles are not compared with those shown in the
database. A separate assessment is shown in section 3.4.
The figures shown in the following sections present the mean values for each fuel (petrol, diesel
and LPG). The number of data items taken into account in the mean value calculation is indicated
on each figure.
3.2.1
Regulated emissions
They include CO, HC, NOx and particulates.
3.2.1.1 NOx emissions
Background
NOx emissions represent both NO and NO2 emissions. They have a wide variety of health and
environmental impacts because of their intrinsic properties and the properties of derivatives (nitric
acid, nitrates, and nitric oxide). Their influence on ozone formation and acidification has led to a
constant drop in regulated emission levels. The respective emission levels of NO and NO2 were
also studied (see section 3.2.3.5).
Results
The results obtained for NOx emissions on the NEDC are summarised in the following figure:
19
0.600
0.433
LPG/diesel : -95.8%
LPG/Petrol : -68.0%
0.351
NOx (g/km)
0.400
0.381
0.500
Number of data :
Diesel : 9
Petrol : 8
LPG : 9
0.300
NEDC
0.200
Euro 3
0.007
0.033
0.016
EUDC
0.036
0.100
0.073
0.050
ECE
Euro 4
0.000
Diesel
Petrol
LPG
Figure 12: NOx emissions on the NEDC.
NOx emissions from LPG vehicles are far below the Euro 3 limit (0.15 g/km) and even Euro 4
(0.08 g/km). For the whole fleet, the global reduction for LPG in comparison with diesel and petrol
vehicles is respectively 96% and 68%.
Moreover, NOx emissions on the NEDC as a function of vehicle inertia are shown in Figure 13. All
the NOx emissions of diesel vehicles are between 0.3 and 0.5 g/km, while those of petrol and LPG
vehicles are generally below 0.1 g/km. Moreover, for most vehicles NOx emissions are lower for
LPG than for petrol. Nevertheless, due to the very low emission levels, it is difficult to conclude
with reliability.
20
0.6
LPG
Petrol
Diesel
0.5
Euro 3 diesel
T P
E
W
NOx (g/km)
0.4
C
Y
H
R
F
0.3
0.2
C
R
E
YR
C
Y
W
0.1
H
H
0
1000
1100
W
1200
Euro 3 Petrol / LPG
1300
1400
E
FF
1500
TTP
1600
1700
1800
Vehicle Inertia (kg)
Figure 13: NOx emissions on the NEDC versus vehicle inertia.
Table 13 (see section 7.4.1) presents the individual numerical results for NOx emissions on the
NEDC.
NOx emissions with LPG are roughly 90% less than those of diesel.
For most vehicles, the use of LPG instead of petrol still had a positive impact on NOx emissions.
The only exception is the vehicle "T" (LPG emissions higher than petrol emissions). Nevertheless,
it has to be underlined that the emissions of both LPG and petrol vehicles are very low, in
comparison with Euro 3 and even Euro 4 levels (0.08 g/km).
These results are also confirmed for the other driving cycles: e.g. results achieved on the CADC.
21
0.839
1.000
Number of data :
Diesel : 9
Petrol : 8
LPG : 9
0.964
0.974
1.200
LPG/Diesel : -95.1%
LPG/Petrol : -53.7%
0.658
NOx (g/km)
0.800
0.600
0.034
0.042
0.083
0.041
0.077
0.090
0.089
0.200
0.168
0.400
CADC
CADC Urban
CADC Road
CADC Motorway
0.000
Diesel
Petrol
LPG
Figure 14: NOx emissions on the CADC.
The Table 22 (see section 7.4.1) presents the reduction percentages for LPG vehicles compared to
corresponding diesel and petrol vehicles for the CADC.
This table shows that the NOx emission level of LPG in comparison with diesel is low for all
driving situations (at least 86% reduction), due to the presence of a three-way catalyst. Moreover,
even compared with petrol results, the emissions of NOx are low when running on LPG (reduction
up to 88%), showing an impact of LPG on the combustion temperature.
Summary
NOx is a major pollutant issue, especially in the urban areas. For all the vehicles tested, the NOx
emissions of the LPG vehicles are significantly lower than the diesel vehicles (reduction by more
than 80%).
3.2.1.2 CO emissions
Background
The regulated levels of CO have fallen dramatically over the last 20 years, as shown in Figure 1,
due to the high toxicity of this product. With generalisation of the use of oxidation and three-way
catalysts, the CO levels at the exhaust of modern vehicles are now low.
Results
The mean results obtained on the NEDC are summarised in the Figure 15.
22
This figure shows that the mean CO emissions for the 3 technologies already comply with Euro 4
levels.
2.500
2.050
Number of data :
Diesel : 9
Petrol : 8
LPG : 9
LPG/diesel : x 5
LPG/Petrol : +26%
0.728
1.000
0.000
Diesel
NEDC
ECE
0.178
0.247
EUDC
0.001
0.200
0.500
0.915
1.500
0.533
CO (g/km)
1.659
2.000
Euro 3
Euro 4
Petrol
LPG
Figure 15: CO emissions, mean values on the NEDC.
Diesel vehicles traditionally have very low CO emission level, due to their lean-burn running
conditions. Euro 3 limits illustrate this fact, with CO emission limits of 2.3 g/km for petrol engines
and only 0.64 g/km for diesel engines. Measured emissions from LPG vehicles are about 5 times
higher than diesel vehicles.
By comparison with petrol vehicles, the level of CO emission recorded for LPG vehicles is more
surprising: the combustion mode and the after-treatment system are the same. The explanation of
this high value can be found in the study of individual emission levels, as shown in the Figure 15
and Table 33 (section 7.4.3):
23
2.5
LPG
Petrol
Diesel
Euro 3 Petrol / LPG
2
Y
CO (g/km)
C
1.5
H
C
Y
R
E
R
W
1
H
W
0.5
H
0
1000
1100
1200
E
F
CF
Y
F
R
W
E
1300
1400
TP
Euro 3 diesel
T
T
P
1500
1600
1700
1800
Figure 16: CO emissions versus vehicle inertia (NEDC).
Figure 16 and Table 36 show that the high global CO emission level for LPG is mainly due to three
vehicles out of the nine vehicles tested: H, C, Y (respectively x 2, x 1.3 and x 2.1). On the other
hand, three vehicles (E, R and T) present lower CO emissions than the corresponding petrol
vehicle.
An examination of the continuous recording of CO emission and equivalence ratio on the NEDC
(Figure 17, Figure 18) explains this phenomena:
24
160
240
140
210
LPG
Petrol
Speed
180
100
150
80
120
60
90
40
60
20
30
0
0
200
400
600
800
1000
Speed (km/h)
CO emission (mg/s)
120
0
1200
time (s)
Figure 17: continuous CO emission measurements (vehicle "Y", NEDC).
Figure 17 shows an increase in CO emission with each deceleration. On Figure 18, changes in the
equivalence ratio (ratio between the actual mass of fuel introduced in the cylinder and the
theoretical mass in stoichiometric conditions) show that at each deceleration in petrol mode, an
injection cut leads to a sharp drop in the injected fuel quantity and consequently a reduction of the
equivalence ratio.
This does not occur in LPG mode, where there is no injection cut (or, at least, a late injection cut).
The equivalence ratio consequently presents a strong increase (up to 1.3), which induces an
increase of CO emissions.
It appears that, for some vehicles tested, injector closing was deliberately delayed in order to
enhance vehicle driveability. This results in a reduction of CO emissions.
25
1.4
140
1.3
120
100
1.1
80
1
60
0.9
Speed (km/h)
Equivalence ratio
1.2
40
0.8
20
0.7
0.6
0
200
400
600
800
0
1200
1000
time (s)
Figure 18: Equivalence ratio measurements (NEDC) – vehicle "Y"
On the warm driving cycles, the results are quite similar:
1.346
0.706
0.623
0.800
0.702
1.000
Number of data :
Diesel : 9
Petrol : 8
LPG : 9
LPG/Diesel : x 151
LPG/Petrol : +6%
0.888
1.030
1.200
1.094
1.400
0.600
CADC
CADC Urban
CADC Road
CADC Motorway
Diesel
0.003
0.000
0.003
0.200
0.049
0.400
0.007
CO (g/km)
1.419
1.600
Petrol
LPG
Figure 19: mean CO emissions, CADC
26
0.232
0.250
CO (g/km)
0.245
0.263
0.263
0.300
0.294
0.315
0.350
Number of data :
Diesel : 9
Petrol : 8
GPL : 9
LPG/Diesel : x 27
LPG/Petrol : 0%
0.200
0.150
warm NEDC
warm ECE
warm EUDC
0.002
0.010
0.050
0.023
0.100
0.000
Diesel
Petrol
LPG
Figure 20: mean CO emissions, warm NEDC.
Summary
All the vehicles tested comply with Euro 3. Nevertheless, a higher CO emission level was
measured for some LPG vehicles and this was explained by air/fuel ratio drifts during deceleration
phases. This demonstrates the strong influence of vehicle ECU calibration optimisation.
3.2.1.3 HC emissions
Background
HC emissions have fallen dramatically over recent years. The HC emissions of internal combustion
engines consist of volatile compounds, some of which are suspected of significantly impacting
public health (benzene, 1,3-butadiene, formaldehyde…) and the greenhouse effect (methane) or
ozone formation.
Results
All emission values are very low, and for LPG vehicles always below the Euro 4 target, with the
exception of one vehicle. The mean HC emission level is 0.06 g/km in LPG, 0.07 g/km in petrol
and 0.03 g/km in diesel (see figure 21 below).
27
0.250
0.195
Number of data :
Diesel : 9
Petrol : 8
LPG : 9
LPG/diesel : +115%
LPG/Petrol : -19%
0.150
0.061
ECE
EUDC
Euro 3
0.003
0.004
0.007
0.028
0.050
NEDC
0.075
0.100
0.065
HC (g/km)
0.159
0.200
Euro 4
0.000
Diesel
Petrol
LPG
Figure 21: Mean HC emissions, NEDC.
As for CO emissions, the HC emissions for LPG vehicles are higher than those of diesel vehicles,
due to a different combustion mode (lean-burn for diesel engines). Nevertheless, in comparison
with petrol, overall LPG has a positive impact on HC emissions, with a decrease of about 20% in
the mean emission level. The individual results are presented in the Figure 22.
0.25
LPG
Petrol
Diesel
Euro 3 Petrol / LPG
HC (g/km)
0.2
0.15
Y
EY
R
HH
0.1
E
C
C
R
W
Y
0.05
W
W
H
0
1000
1100
1200
1300
1400
Euro 4 Petrol / LPG
C
T
F
R
F
E F
1500
1600
1700
Figure 22: HC emissions versus vehicle inertia (NEDC).
28
T
T
P
P
1800
The maximum emission level is 0.12 g/km for LPG and petrol and 0.06 g/km for diesel.
Most of the LPG vehicles are below the Euro 4 limit.
The LPG vehicles C, H and Y showing the highest HC emissions, correspond to vehicles with high
CO emissions. This is explained by the equivalence ratio during deceleration phases (see section
3.2.1.2).
As far as warm cycles are concerned, the results show similar behaviour, with very low emission
levels:
0.031
0.035
0.026
0.026
0.030
Number of data :
Diesel : 9
Petrol : 8
LPG : 9
LPG/Diesel : +3.4%
LPG/Petrol : +8.8%
0.014
0.007
0.013
0.011
0.010
0.010
0.012
0.009
0.015
0.014
0.020
0.012
HC (g/km)
0.025
0.005
CADC
CADC Urban
CADC Road
CADC Motorway
0.000
Diesel
Petrol
LPG
Figure 23: HC emissions – CADC
Calculation shows that, with a 10 m3/min CVS (typical value for the method), a value of 0.03 g/km
on the NEDC corresponds to an HC concentration of about 2 – 3 ppmV, which is very close to the
concentration measured in the air used for dilution. Therefore the measured HC emissions are at an
extremely low level.
Summary
All the vehicles tested had very low HC emissions, close to the reliability limit of the HC
measurement method.
29
3.2.1.4 PM emissions
Background
Particulate mass emissions are currently only regulated for diesel vehicles. Only diesel vehicles
present a significant particulate mass emission level. In most industrialised countries this is also
recognized as an indicator of ambient air pollution.
The potential adverse health effects of particulate air pollution has been a major focus of attention
for many years. A substantial number of publications have appeared in scientific and popular
literature demonstrating a correlation between particulate air pollution levels in regions and cities
and a number of adverse health effects, including the number of hospital admissions for cardiac and
pulmonary disease, increased asthmatic symptoms and mortalities i.e. in individuals whose health
is already impaired.
Results
Since it is not a regulated emission, the test protocol only requires particulate mass measurement
for petrol and LPG vehicles on the CADC.
Nevertheless, particulate mass measurements on the NEDC were done for 3 vehicles ("R", "Y" and
"H", see Figure 24).
Part (g/km)
0.06
0.05
Number of datas :
Diesel : 3
Petrol : 3
LPG : 3
0.04
LPG/Diesel : -99%
LPG/Petrol : n.s
0.03
0.02
NEDC
ECE
EUDC
Euro 3
Euro 4
0.01
0
Diesel
Petrol
LPG
Figure 24: mean PM emissions, NEDC.
30
0.06
LPG
Petrol
Diesel
Euro 3 diesel
0.05
H
PM (g/km)
0.04
0.03
Y
Euro 4 diesel
R
0.02
0.01
Y
RR
Y
HH
0
1000
1100
1200
1300
1400
1500
1600
Vehicle inertia (kg)
Figure 25: PM emissions, NEDC.
The Figure 25 shows the wide gap in PM emissions between diesel and spark-ignition engines
(petrol and LPG) on individual vehicles. No significant difference can be observed between petrol
and LPG vehicles, due to very low masses, far below the measurements method reliability limit.
On the CADC, PM were measured on more vehicles, with similar conclusions, as shown in the
Figure 26:
0.060
0.050
Number of data :
Diesel : 9
Petrol : 7
LPG : 8
0.042
0.042
0.050
LPG/Diesel : -88.9%
LPG/Petrol : -9.0%
0.030
0.028
0.000
Diesel
Petrol
LPG
Figure 26: mean PM emissions, CADC.
31
0.007
0.001
0.002
0.005
0.001
0.001
0.010
0.010
0.020
0.005
PM (g/km)
0.040
CADC
CADC Urban
CADC Road
CADC Motorway
This figure shows the very low PM emission levels of petrol and LPG vehicles. The mean values
are around 3 to 4 mg/km, which is below the reliable measurement limit of the sampling method
described in the 70/220 directive.
Summary
The particulate mass measurements show the low emission level of spark-ignition engines (petrol
and LPG), which is always below the quantification limit of the method.
3.2.2
CO2 emissions
Background
CO2 is considered as a major contributor to the greenhouse effect. (see section 3.3.4)
In July 1998 ACEA made a voluntary commitment with the EU to reduce new passenger cars CO2
emissions [1]. This commitment is based on 5 points:
1. the marketing of individual car models with CO2 emissions of 120 g/km or less by 2000;
2. an average CO2 emission level of 140 g/km by 2008 for new cars sold in the EU – a 25%
reduction compared to 1995;
3. an estimated target range of 165–170 gCO2/km in 2003 – a 9-11% reduction compared to 1995;
4. in 2003, review of the potential for additional improvements in order to raise the new car fleet
average to 120 gCO2/km by 2012;
5. joint ACEA/Commission monitoring of all the relevant factors related to the commitments.
In this context, the marketing of low CO2 emission vehicles is of paramount importance. Since
1998, the CO2 commitment has been fulfilled mainly by an increase in the diesel vehicle
population.
Recent discussions between car manufacturers and the European Commission about the
implementation of this commitment have shown that this goal remains difficult to reach.
Results
The results obtained on the vehicles tested are presented in the following figures:
32
300.0
250.9
150.0
LPG/diesel : +6.4%
LPG/Petrol : -11.0%
131.8
147.0
128.0
155.1
200.0
165.1
185.4
201.4
222.0
250.0
CO2 (g/km)
Number of data :
Diesel : 9
Petrol : 8
LPG : 9
NEDC
100.0
ECE
EUDC
50.0
ACEA 2008
ACEA 2012
0.0
Diesel
Petrol
LPG
Figure 27: CO2 emissions, NEDC.
The individual numerical results are presented in Table 23 (see section 7.4.2).
LPG emits 11% less CO2 than petrol ones and 6% more than diesel vehicles. Nevertheless, a study
of individual results for each vehicle shows that this percentage is more dependent on the vehicle
technology (especially mapping) than inertia, as shown in the Figure 28.
240
220
T
LPG
Petrol
Diesel
T
E
T
CO2 (g/km)
200
R
C
W
180
R
Y
W
C
Y Y
H
160
120
1000
C
E F
F
R
P
P
W
H
140
F
E
H
1100
1200
1300
1400
1500
1600
1700
Figure 28: CO2 emissions versus vehicle inertia (NEDC).
33
1800
This figure shows the strong impact of vehicle technology:
- The LPG/Diesel comparison varies between 6% less and 17% more.
Vehicle "C" has lower CO2 emissions in LPG than in diesel.
Vehicle "Y" LPG emissions (149.6 g/km) are very close to diesel (148.3 g/km), despite
its recent diesel technology (high pressure direct injection, "common-rail" type).
Therefore the good performances of LPG vehicles compared to diesel vehicles cannot be
seen as the consequence of old-fashioned diesel technology.
This is also the case for vehicles "H" and "F".
- For all the vehicles, the impact of LPG on CO2 emissions is positive in comparison with
petrol. The variation is between 8% less (vehicle "R") and 14% less (vehicle "C").
As far as warm driving cycles are concerned, similar results can be observed, as shown in the
following figures:
250.0
194.6
218.4
Number of data :
Diesel : 9
Petrol : 8
GPL : 9
LPG/Diesel : +7.9%
LPG/Petrol : -10.7%
128.7
152.9
143.5
124.2
150.0
141.7
CO2 (g/km)
171.3
171.2
200.0
100.0
warm NEDC
warm ECE
warm EUDC
50.0
0.0
Diesel
Petrol
LPG
Figure 29: CO2 emissions, warm NEDC.
34
279.6
159.8
160.7
175.9
177.4
159.7
146.3
150.0
144.9
160.6
CO2 (g/km)
200.0
164.0
228.7
250.0
Number of data :
Diesel : 9
Petrol : 8
LPG : 9
247.3
300.0
LPG/Diesel : +0.1%
LPG/Petrol : -9.4%
100.0
CADC
CADC Urban
CADC Road
CADC Motorway
50.0
0.0
Diesel
Petrol
LPG
Figure 30: CO2 emissions, CADC.
The low CO2 emissions level of LPG vehicles is mainly observed in high speed / high load driving
cycles.,
In addition, the mean CO2 emission level, (global CADC calculated on the basis of the 3 realistic
phases with urban (10%), road (37%) and motorway (53%)) is equivalent for LPG and diesel (not
more than +0.1%) and much lower for LPG than for petrol (-9,4%).
As far as the CADC is concerned, CO2 emissions from LPG vehicles are equivalent or lower than
those of diesel vehicles for approximately half of the vehicles (5 out of 9) and in any case lower
than those of petrol vehicles.
In addition, the mean CO2 emission level is equivalent for LPG and diesel.
As for CO, the vehicle ECU calibration impacts the CO2 emissions:
q
The LPG vehicle "R", which showed lower CO2 emissions on the NEDC than diesel one, has
higher emissions on the CADC, due to Road (+4%) and Motorway (+6%) cycles, as opposed to
the urban cycle (low speed) (-1%).
q
On the other hand, vehicle "E" in LPG mode seems to be more optimised for Road and
Motorway cycles (respectively –2% and –9%) than for Urban cycle (+5%, and +8% on the
NEDC).
The following figure based on 36% urban, 37% road and 27% motorway (typical driving
conditions in France according to a survey (SOFRES) done in 1999) shows that CO2 emissions for
LPG vehicles are however slightly higher than those of diesel vehicles and still significantly lower
than petrol ones.
35
279.6
Diesel
Petrol
LPG
Number of data :
Diesel : 9
Petrol : 8
LPG : 9
186.3
207.2
180.2
159.8
164.0
146.3
150.0
159.7
144.9
200.0
175.9
247.3
250.0
228.7
300.0
LPG/Diesel : +3.4%
LPG/Petrol : -10.1%
100.0
50.0
0.0
CADC Urban
CADC Road
CADC Motorway
CADC "France"
Figure 31: CO2 emissions - CADC "France"
Individual results for the CADC "France" have also been calculated and are presented in the Figure
32 :
280
260
LPG
Petrol
Diesel
T
CO2 "France" (g/km)
240
T
220
200
W
R
W
C
H
180
Y
160
H
E
C
R
Y
Y
F
E
F
T
C
E
R
F
P
P
H
W
140
120
1000
1100
1200
1300
1400
1500
1600
1700
1800
Figure 32 : individual results for CO2 emissions, CADC "France".
This calculation shows that the use of country-specific weighting rates, even if it induces a change
in the numerical values, does not radically modify the respective positions of the fuels.
36
Summary:
On the vehicles tested, the mean CO2 emissions of LPG vehicles are between those of diesel and
petrol vehicles, but closer to diesel. This conclusion is also valid for the CADC, regardless of the
relative importance given to each phase. It was shown that an appropriate ECU calibration can
lower the CO2 emissions of LPG vehicles to diesel levels in certain driving conditions.
In addition to this analysis, a well to wheel assessment has been led and is presented in section
3.3.4.
37
3.2.3
Unregulated Pollutant emissions results
Unregulated pollutant emissions were measured on NEDC for three models. In addition, they were
measured on the CADC for all the vehicles.
The molecules quantified were:
- oxygenated compounds (aldehydes)
- Benzene, Toluene, xylenes ("BTX")
- Poly-Aromatic Hydrocarbons ("PAH")
- Particle size measurements
Moreover, some N2O and NO2 measurements were taken but most of them were below the
detection limit.
3.2.3.1 Oxygenated products
Background
Aldehydes are irritants and their toxicity increases with lower molecular weight.
Formaldehyde, which irritates the ocular mucous membranes in low concentrations, irritates the
throat and bronchial tubes as the concentration rises[3].
The most prominent features of formaldehyde vapour are its pungent odour and its irritant effects
on the mucosa of the eyes and upper airways. Odour-detection thresholds are generally reported to
be in the range of 0.1-0.3 mg/m3. Eye and respiratory-tract irritation generally occurs at levels of
about 1 mg/m3, but discomfort has been reported at much lower levels. Moreover, WHO reports
have stressed the fact that formaldehyde is positive in a wide range of mutagenicity test systems in
vitro ; it has been shown to form DNA-protein crosslinks in vitro and in vivo [8].
Results
Oxygenated compound emissions are mainly composed of formaldehyde and acetaldehyde, as
shown in the Figure 33. Moreover, this figure shows that LPG emissions are globally much lower
than diesel emissions.
38
2
Formaldehyde
Acrolein
Propionaldehyde
n-butyraldehyde
i-valeraldehyde
o-tolualdehyde
p-tolualdehyde
2,5-dimethylbenzaldehyde
1.8
emissions (mg/km)
1.6
1.4
1.2
Diesel
Acetaldehyde
Acetone
Crotonaldehyde
Benzaldehyde
n-valeraldehyde
m-tolualdehyde
Hexanaldehyde
Petrol
LPG
1
0.8
0.6
0.4
0.2
Vehicle Y
Vehicle W
Vehicle T
Vehicle R
Vehicle H
Vehicle F
Vehicle E
Vehicle C
Vehicle Y
Vehicle W
Vehicle T
Vehicle R
Vehicle H
Vehicle F
Vehicle E
Vehicle C
Vehicle Y
Vehicle W
Vehicle T
Vehicle R
Vehicle H
Vehicle F
Vehicle E
Vehicle C
0
Figure 33: oxygenated compounds repartition - CADC.
On the NEDC, unregulated pollutant emissions were measured for only 3 vehicles, as shown in the
Figure 34:
39
9
acroleine
acetaldehyde
formaldehyde
8
emissions (g/km)
7
6
5
4
3
2
1
0
Diesel
Petrol
LPG
Figure 34: Mean formaldehyde / acetaldehyde / acroleine values - NEDC (data on 3 vehicles)
On the NEDC, on the 3 vehicles for which oxygenated compounds were measured, LPG produces
90% less formaldehyde emissions than diesel. The result is even greater in the CADC (Figure 35):
9
acroleine
acetaldehyde
formaldehyde
8
emissions (g/km)
7
6
5
4
3
2
1
0
Diesel
Petrol
LPG
Figure 35: Mean formaldehyde / acetaldehyde / acroleine values - CADC (data on 9 vehicles
for Diesel and LPG and 8 vehicles for petrol)
The emissions of spark-ignition vehicles (petrol and LPG) are much lower than those of diesel
vehicles.
Data show that LPG emissions are lower than those of petrol (68% less) .
However, this very low emission level is in the same range as the detection level of the
measurement method.
40
Summary
The measurement of oxygenated compounds (aldehydes) has shown that these emissions are
mainly composed by formaldehyde and acetaldehyde.
The formaldehyde emission of LPG on the CADC is much lower than that for diesel (95% less).
3.2.3.2 PAH results
Background
PAH (Poly Aromatic Hydrocarbons) are suspected for their carcinogenicity. Most of them were
classified in class "2" by IARC (International Agency for Research on Cancer).
In this class, 2 types of PAH can be found:
- category "2A" (probably carcinogenic: Benzo(a)anthracene, benzo(a)pyrene,
dibenzo(a,h)anthracene.
- Category "2B" (possibly carcinogenic): benzo(b)fluoranthene, benzo(k)fluoranthene,
indeno(1,2,3-cd)pyrene, dibenzo(a,h)pyrene.
Results
The emissions of total PAH, "2A" and "2B" PAH are presented in the following figures:
31.54
35.00
Number of data :
Diesel : 9
Petrol : 8
LPG : 8
30.00
12.23
20.00
LPG/Diesel : -25.9%
LPG/Petrol : -61.2%
16.50
PAH (µg/km)
25.00
15.00
10.00
5.00
0.00
Diesel
Petrol
LPG
Figure 36: total PAH emissions - CADC.
41
The level of PAH is very low for all fuels: around 10 µg/km (whereas the global HC emission level
is around 1 mg/km).
As shown in the following figures, the emissions level for "2A" and "2B"PAH seems low in
comparison with petrol and diesel vehicles. Indeed, the emissions of LPG vehicles are 28% lower
for "2A" PAH and more than 60% lower for "2B" PAH than diesel vehicles.
0.30
0.26
Number of data :
Diesel : 9
Petrol : 8
LPG : 9
LPG/Diesel : -27.5%
LPG/Petrol : -54.0%
0.20
0.17
0.15
0.12
"2A" PAH (µg/km)
0.25
0.10
0.05
0.00
Diesel
Petrol
LPG
Figure 37: "2A" PAH emissions - CADC
0.35
0.30
Number of data :
Diesel : 9
Petrol : 8
LPG : 9
0.30
LPG/Diesel : -68.7%
LPG/Petrol : -79.0%
0.20
0.20
0.15
0.10
0.06
"2B" PAH (µg/km)
0.25
0.05
0.00
Diesel
Petrol
LPG
Figure 38: "2B" PAH emissions - CADC.
42
The measured emission level for LPG is lower than for Petrol and Diesel, however the levels of
individuals PAHs measurements show important variations (Figure 39)
200
180
Emission (µg/km)
160
140
120
100
80
60
40
Vehicle Y, LPG
Vehicle Y, Gasoline
Vehicle Y, Diesel
Vehicle W, LPG
Vehicle W, Gasoline
Vehicle W, Diesel
Vehicle T, LPG
Vehicle T, Gasoline
Vehicle T, Diesel
Vehicle R, LPG
Vehicle R, Gasoline
Vehicle R, Diesel
Vehicle P, LPG
Vehicle P, Diesel
Vehicle H, LPG
Vehicle H, Gasoline
Vehicle H, Diesel
Vehicle F, LPG
Vehicle F, gasoline
Vehicle F, Diesel
Vehicle E, LPG
Vehicle E, Gasoline
Vehicle E, Diesel
Vehicle C, LPG
Vehicle C, gasoline
0
Vehicle C, Diesel
20
Figure 39: PAH emissions, individual results
This figure shows that the PAH emissions results are very inconsistent depending on the vehicle.
For instance, PAH emissions are high for the LPG vehicle "F", while they are low for the vehicles
"T", "Y" or "C". This inconsistency can be due to differences between analytical methods: for the
vehicles "R", "Y" and "H", the PAH were only measured for the solid phase, and not the volatile
phase.
Consequently the reliability of the method at this level of measurement and the vehicle
technologies are much more influencing factors than the type of fuel.
Summary
PAH emissions are important due to the suspected carcinogenicity of these compounds. The
classifications "2A" and "2B" set-up by IARC reflect this toxicity.
The measurements have shown an important variation between the different vehicles, due to very
low emission levels. This might be the consequence of the lack of reliability of the measurements,
pollution by crank oil or differences between vehicle technologies...
43
3.2.3.3 BTX emissions
Background
In the "BTX" section are described monoaromatic compounds:
- Benzene
- Toluene
- Xylenes
Benzene is known for its high toxicity. It has been classified by IARC (International Agency for
Research on Cancer) in the category 1 (Carcinogenic for humans: a causal relationship has been
established between exposure to the agent, mixture or exposure circumstance and human cancer.).
Results
Number of data :
Diesel : 3
Petrol : 3
LPG : 3
2.24
2.50
LPG/diesel : +69%
LPG/Petrol : -74%
1.50
1.00
0.50
0.34
0.57
benzene (mg/km)
2.00
0.00
Diesel
Petrol
LPG
Figure 40: Mean benzene emissions - NEDC
The benzene level is limited in petrol (1%vol). Nevertheless, the important amount of aromatic
compounds used in the petrol product specification (up to 42%vol) induces high benzene
emissions. On the contrary, no aromatic compounds can be found in the LPG. For diesel fuel,
aromatic compounds can be found, but the initial distillation point is too high to allow the presence
of benzene in its composition. Consequently, the emissions of benzene for diesel and LPG vehicles
are very low (around 0.5 mg/km on the NEDC).
44
0.70
0.61
Number of data :
Diesel : 9
Petrol : 8
LPG : 9
0.60
LPG/Diesel : -27.7%
LPG/Petrol : -82.2%
0.40
0.30
0.15
0.20
0.11
benzene (mg/km)
0.50
0.10
0.00
Diesel
Petrol
LPG
Figure 41: Mean benzene emissions - CADC.
On the CADC, with more data (9 vehicles), the conclusions are similar: LPG demonstrates a
considerable reduction of benzene emissions compared to petrol vehicles (70% less). The emissions
level is similar to the one found for diesel vehicles (Figure 41).
1.4
1.2
H
LPG
Petrol
Diesel
C
E
benzene (mg/km)
1
W
0.8
0.6
T
0.4
0.2
Y
W
H
Y
H
RW
YR
C
0
1000
1100
1200
1300
1400
T
EC E
R F
F F
1500
T
PP
1600
1700
Figure 42: Benzene emissions versus vehicle inertia - CADC.
45
1800
Figure 42 shows that the results are coherent: the petrol vehicles always demonstrate higher
benzene emission levels.
1.70
The same conclusion can be drawn for BTX emission as already drawn for benzene:
1.80
Number of data :
Diesel : 9
Petrol : 8
LPG : 9
1.60
1.40
LPG/Diesel : -12.4%
LPG/Petrol : -84.5%
BTX (mg/km)
1.20
1.00
0.80
0.26
0.40
0.30
0.60
0.20
0.00
Diesel
Petrol
LPG
Figure 43: mean BTX emissions - CADC.
The total BTX level is similar for diesel and LPG vehicles, and much lower than for petrol
vehicles. The individual results (Figure 44) show that all vehicles have a similar behaviour.
46
5
4.5
E
LPG
Petrol
Diesel
4
BTX (mg/km)
3.5
H
3
C
2.5
2
1.5
W
1
H
0.5
0
1000
1100
Y
Y
R
H
Y W
W
R
C
1200
1300
1400
T
RC FE
E
F F
1500
T
1600
PP
T
1700
1800
Figure 44: BTX emissions versus vehicle inertia - CADC.
Summary
BTX is of major concern, mainly due to its impact on health and their carcinogenicity. The results
show that the BTX emission level of LPG vehicles is close that measured for diesel vehicles. Petrol
vehicles, due to the high aromatic content of the fuel, have a significantly higher emission level
(multiplied by 6).
47
3.2.3.4 Particle Size
Background
Particles are suspected to have a strong impact on health, due to their penetration of respiratory
tracts. Among the physical and chemical characteristics of inhaled particles, which can have a
profound effect on the nature of the toxicity produced in both laboratory animals and humans, the
particle size (and the interrelated parameters: volume, surface and number) is a major determinant.
Their penetration of respiratory tracks is indeed strongly linked to their size, as shown in the Figure
45, which is based on the IPCC 66 model [4][5].
Figure 45: Schematic overview of total deposited fraction (A) and of deposited fraction in the
extrathoracic (B), in the tracheobronchial (C) and in the alveolar region (D) of the human
respiratory system for unit-density spheres during mouth breathing.
The deposited fraction ranges between 0 and 1: a fraction of 0.5 means that 50% of the concerned
particle is deposed.
Particle size measurements were done using the ELPI method (Electrical Low Pressure Impactor).
The principle of this measurement method is to separate the particles according to their
aerodynamic diameter. The apparatus consists of a series of impaction plates, characterised by a cut
diameter: the geometry of each plate is designed to stop particles with a diameter greater than a
given value.
In each plate, the gas flow is rapidly deflected. Particles with a high diameter are dragged by their
inertia and impact the collection plate where they are counted using an electrical method.
48
Results
The breakdowns obtained for all the vehicles are presented in the Figure 46. The mean values
calculated on all the vehicles are presented in the Figure 47.
1.0E+16
Diesel
Petrol
LPG
dN/dlogDp (part/km)
Logarithmic scale
1.0E+15
1.0E+14
1.0E+13
1.0E+12
1.0E+11
1.0E+10
0.01
0.1
1
Di (µm) - logarithmic scale
Figure 46: ELPI measurements - All vehicles - CADC.
1.E+15
Diesel
Petrol
LPG
Dn/DlogDp (part/km)
1.E+14
1.E+13
1.E+12
1.E+11
1.E+10
0.01
0.1
Diameter (µm) - logarithmic scale
Figure 47 : ELPI measurements - mean values - CADC cycle.
49
1
The ELPI results are quite difficult to assess. Many parameters can influence the particle size. For
instance, it can be seen that diesel vehicles have a high emission level in the range of size generally
studied (0.03 µm – 0.1 µm). For petrol and LPG vehicles, very small particle (0.01 – 0.02 µm)
emission levels appears to exceed those of diesel vehicles. This is a consequence of the nucleation
phenomenon: under specific circumstances, the presence in the exhaust line of gaseous molecules
can lead to the appearance of liquid droplets composed of sulphates, water, heavy aromatic
compounds etc. This aerosol is radically different from the one measured at the exhaust of diesel
vehicles: no solid fraction can be observed. Nevertheless, it is measured by the ELPI just like solid
particles.
This phenomenon is common and has been recently studied ([6][7]). It can generally be observed at
the exhaust of petrol vehicles or diesel vehicles equipped with DPF. Indeed, when solid particles
are present at the exhaust, they "absorb" all the liquid compounds. When no solid particles can be
found, those compounds can nucleate and consequently can lead to this type of aerosol.
As far as solid particles are concerned (above 0.04 µm), LPG and petrol emissions are 100 to 1000
times lower than those of diesel vehicles, as shown in the Figure 48:
2.0E+14
Diesel
Petrol
LPG
1.8E+14
dN/dlogDp (part/km)
1.6E+14
1.4E+14
1.2E+14
1.0E+14
8.0E+13
6.0E+13
4.0E+13
2.0E+13
1.0E+08
0.01
0.1
1
Di (µm) - logarithmic scale
Figure 48: Solid particles emissions - CADC
Summary
Particle size seems to be an important parameter influencing the health effect. The measurements
done on the vehicles tested showed a very low emission level for spark-ignition engines (petrol and
LPG) in the range of solid (carbon) particles (0.040 µm – 0.015 µm). For smaller sizes, the
emission level is difficult to measure, and the components are difficult to identify due to the
presence of nucleation aerosols.
50
3.2.3.5 NO2 emissions
Background
NOx (nitrogen oxides) were considered in section 3.2.1.1. They include NO (nitric oxide) and NO2
(nitrogen dioxide).
NO2 is also subject to further major atmospheric transformations that lead to the formation of O3
and other strong oxidants which participate in the conversion of NO2 to nitric acid and SO2 to
sulphuric acid and subsequent conversions to their ammonium neutralisation salts. Thus, through
the photochemical reaction sequence initiated by the solar-radiation-induced activation of NO2, the
newly generated pollutants formed are an important source of nitrate, sulphate and organic aerosols
that can contribute significantly to total PM10 or PM2.5 mass. For these reasons, NO2 is a key
precursor for a range of secondary pollutants whose effects on human health are well documented.
Therefore, health risks from NOx may potentially result either from NO2 itself (effect on the
respiratory system), or through reaction products of NO2, including O3 and secondary particles
(acid rain). Epidemiological studies of NO2 are not able to segregate between both.
The oxidation of NO in NO2 is a fairly rapid process in ambient air. Nevertheless, the NO / NO2
ratio is a key factor for the models dealing with ozone formation forecasts which are not examined
in this report.
NO2 levels are generally a recognised marker of traffic consequence, since NO2 is proportional to
traffic (volume and vehicle fuel technology) [2].
Results
NO2 was measured on three vehicles on the NEDC and on 6 vehicles on the CADC.
51
64.29
47.81
LPG/diesel : -45.7%
LPG/Petrol : +17.8%
26.02
31.16
23.46
30.00
27.51
40.00
26.45
NO2 (%age)
50.00
35.47
60.00
Number of data :
Diesel : 3
Petrol : 3
LPG : 3
57.40
70.00
20.00
NEDC
10.00
ECE
EUDC
0.00
Diesel
Petrol
LPG
Figure 49: mean NO2 proportion of total NOx emissions, NEDC.
70.00
54.96
60.00
Number of data :
Diesel : 6
Petrol : 6
LPG : 6
LPG/Diesel : -67.6%
LPG/Petrol : +1.7%
40.00
17.78
30.00
17.50
NO2 (%age)
50.00
20.00
CADC
CADC Urban
CADC Road
CADC Motorway
10.00
0.00
Diesel
Petrol
LPG
Figure 50: mean NO2 proportion of total NOx emissions, CADC.
52
Figure 49 and Figure 50 show that for both cycles, the proportion of NO2 in the exhaust gases is
higher for diesel vehicles than for petrol and LPG vehicles. Around 60% of NOx emissions consist
of NO2 for diesel vehicles, while this ratio is around 15 to 20% for LPG and petrol vehicles.
Since NO2 appears to be more harmful than NO, the low share of NO2 in petrol and LPG emissions
is seen as a positive aspect of this type of vehicle.
This result has to be combined with the global NOx emission level shown in Figure 51 (see section
3.2.1.1, showing a NOx reduction of 95% for petrol and LPG in comparison with diesel).
0.9
NO2
NO
0.8
NOx emissions (g/km)
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Diesel
Petrol
LPG
Figure 51: NO / NO2 emissions – CADC.
Moreover, a study of the individual vehicle results shows that all the measurements are quite
coherent: The lowest value for NO2 proportion in diesel exhausts is 30% (vehicle W). All the other
values are between 50% and 80% (vehicle R). On the other side, the highest value for LPG is 30%
(vehicle H), while all the other values are below 10% (Figure 52)
53
80
70
LPG
Petrol
Diesel
R
H
T
60
NO2 (%age)
Y
50
E
40
H
H
W R
YY
R
30
20
10
0
1000
W
1100
1200
1300
TT
E
E
1400
1500
1600
1700
1800
Figure 52: individual NO2 proportion (CADC).
Summary
Among NOx emissions, NO2 was more closely examined due to its contribution to acidification,
ozone formation and health effect. Consequently, this pollutant was measured for most of the
vehicles. The results showed that the NO2 proportion is lower for spark-ignition vehicles (around
20% of total NOx emissions) than for diesel vehicles (60% of total NOx emissions).
This should be considered alongside the conclusion of paragraph 3.2.1.1, thus demonstrating the
lower emissions of LPG in comparison with diesel on this particular point.
54
3.3 Environmental impact and health effect
3.3.1
Ozone (O3) Formation
Background
Ozone is the largest photochemical oxidant in the troposphere. It is formed by photochemical
reactions in the presence of precursor pollutants such as NOx and volatile organic compounds
(VOC). In the vicinity of strong NOx emission sources, where there is an abundance of NO, O3 is
“scavenged” and as a result its concentrations are often low in busy urban centres and higher in
suburban and adjacent rural areas. On the other hand, O3 is also subject to long-range atmospheric
transport and is therefore considered as a trans-boundary problem.
According to recent studies led by the WHO (World Health Organization), there is evidence from
controlled human and animal exposure studies of the potential for O3 to cause adverse health
effects. There are few epidemiological studies on the chronic effects of ozone on human health.
Incidence of asthma, a decreased lung function growth, lung cancer and total mortality are the main
outcomes studied. At levels currently observed in Europe, the evidence linking O3 exposure to
asthma incidence and prevalence in children and adults is not consistent. Available evidence
suggests that long-term exposure to O3 reduces lung function growth in children. There is little
evidence for an independent long-term O3 effect on lung cancer or total mortality. The plausibility
of chronic damage to the human lung from prolonged O3 exposure is supported by the results of a
series of chronic animal exposure studies.
Two indexes can be used in order to evaluate the impact of exhaust gases on ground-level ozone:
the TOFP and POCP:
•
•
TOFP: "Tropospheric Ozone Forming Potentials", which is representative of regional
conditions (for example northwest Europe) takes into account the vehicle’s own NOx
emissions. It is consequently calculated according to NOx, NMVOC, CO and methane
emissions, balanced by individual coefficients:
NOx: 1.22, NMVOC: 1, CO: 0.11, CH4: 0.014
POCP: "Photochemical Ozone Creation Potentials", as defined by Derwent and Jenkin, is more
representative of local conditions (e.g. urban area). It describes the relative ability of organic
compounds to generate ozone defined relative to a value of 100 for ethene, and represents the
quantity of ozone formed from the unit mass emission of a given VOC, compared to that from
the emission from an identical mass of ethene. The calculation was done according to the last
version of the coefficients (2003, [12][13]), using 33 molecules. This index is representative of
local conditions.
POCP, more dependent on local conditions, is more representative of the impact of the vehicle on
ozone formation in a local area, defined by its own air composition.
On the contrary, TOFP is representative of the impact on ozone of the vehicle itself.
As a consequence, both are indicators of health impact, but TOFP is a more appropriate index in
relation to the environmental impact.
55
Results
POCP (g eq ethene/km)
2.50
Number of data :
Diesel : 8
Petrol : 7
LPG : 8
2.48
2.50
3.00
LPG/Diesel : x 20
LPG/Petrol : -1%
2.00
1.50
1.00
0.12
0.50
0.00
Diesel
Petrol
LPG
Figure 53: Mean POCP value - CADC.
The POCP value for LPG is similar to the one obtained with petrol vehicles and is substantially
higher than the one obtained for diesel vehicles. Indeed, the POCP calculation was only done for
CO and HC emissions only (and not NOx emissions). Moreover, it was shown previously (see
section 3.2.1.1) that, due to their lean-burn combustion, diesel vehicles have lower CO and HC
emissions, which consequently induce low POCP values.
Nevertheless, when NOx emissions are taken into account (TOFP), the result is inverted, as shown
in Figure 54:
56
1.20
1.04
Number of data :
Diesel : 8
Petrol : 7
LPG : 8
LPG/Diesel : -86.2%
LPG/Petrol : -25.1%
0.80
0.60
0.40
0.20
0.14
0.19
TOFP (gNMVOC eq/km)
1.00
0.00
Diesel
Petrol
LPG
Figure 54: TOFP - CADC.
Summary
Ozone formation is a major concern. Two main indicators were used to evaluate the impact of
engine exhaust emissions on changes in the ozone level, at local level (POCP) or a more regional
level (TOFP).
Both indicate similar behaviour for petrol and LPG vehicles. Nevertheless, different conclusions
can be drawn for diesel vehicles: POCP is higher for spark-ignition vehicles than for diesel
vehicles, due to their higher CO emission level.
On the other hand, as a result of TOFP calculation, the negative ecological impact of petrol and
LPG vehicles is lower than diesel vehicles, due to their low NOx emission level.
3.3.2
Cancer risk
Background
The cancer risk factor for various emission components from different sources varies significantly.
Therefore, it is difficult to give a precise value for a cancer risk factor.
Several sets of risk factors are available from governmental or non-governmental organisations,
such as the US EPA (Environmental Protection Agency), CARB (California Air Resource
Board)…
The most recent dataset comes from OEHHA (Office of Environmental Health Hazard Assessment,
California). In this database, URF (Unit Risk Factors) are given for a wide range of chemical
molecules, expressed as the individual mortality risk for a lifetime (70 years) exposure of 1 µg/m3
for each component.
57
Of the molecules that can be found in the exhaust of internal combustion engines, some have a
considerably high level of URF, as shown in the following table:
Component
URF, as defined by
OEHHA (1999)
300
29
170
6
2.7
110.0
11.0
110.0
110.0
1100.0
110.0
1200.0
Particulates
Benzene
1,3-butadiene
Formaldehyde
Acetaldehyde
Benzo[a]anthracene
Chrysene
Benzo[b]fluoranthene
Benzo[k]fluoranthene
Benzo[a]pyrene
Indeno[1,2,3-cd]pyrene
Dibenzo[a,h]anthracene
URF, as defined by
EPA (1990)
70
8
300
10
2
4000
4000
4000
4000
4000
4000
4000
Table 2: Cancer Potency Values (URF, * 10-6) for selected molecules (OEHHA and EPA)
These URF are very dependent on the source (EPA or OEHHA). Especially, as far as PM is
concerned, the Unit risk Factor is 300 for OEHHA and 70 for EPA. Particulate matter has a
significantly lower risk factor than PAH, but the concentration at the exhaust is often significantly
higher. In order to get a comparison point, the particulate emissions of a typical diesel engine is
around 30 mg/km. This value has to be compared to the measurements of PAH emissions (around 1
µg/km, i.e. 10-3 mg/km). Even with the EPA factors, PM always represents more than 99% of the
calculated cancer risk index.
Results
Since LPG and petrol have very low particulate mass emissions, the Cancer Risk Index is very low,
with a reduction proportional to the PM reduction, as shown in Figure 55, where diesel vehicles
were used as the reference (Diesel = 100). Moreover, it should be noted that calculation of the
Cancer Risk Unit was only done for emission components in the exhaust. Secondary formed
components or components resulting from "scavenging" by rapid oxidation of some of the
emissions were not taken into account [15].
58
120
benzene
1,3-butadiene
Acetaldehyde
Formaldehyde
PAC
Particulates
Cancer Risk Index (Diesel = 100)
100
80
60
40
20
0
OEHHA
Diesel
EPA
Diesel
OEHHA
Petrol
EPA
Petrol
OEHHA
LPG
EPA
LPG
Figure 55: calculation of the cancer risk index according to OEHHA and EPA methods (8
vehicles / technology) – CADC.
The index for petrol and LPG is much lower than for diesel. However, they mainly result from
particulates (see section 3.2.1.4). Moreover, as underlined in the section 4.2.1.4, the particulate
mass measurements done for LPG and Petrol vehicles were below the quantification limit of the
method. The cancer risk index value may consequently be quite unreal. The order of magnitude
will nevertheless be unchanged.
Summary
The cancer risk calculation was developed in order to estimate the carcinogenic effect of chemical
compounds. The assessment of this effect is complex. Two indices (OEHHA (California) and EPA)
were calculated. Both shows an index 10 times lower for spark-ignition engines than for diesel
engines. This factor results from particulate emissions.
3.3.3
Acidification
Background
Atmospheric emissions of acidifying substances such as sulphur dioxide (SO2), nitrogen oxides
(NOx) and ammonia, mainly from the burning of fossil fuels, can persist in the air for up to a few
days and thus can be transported over thousands of kilometres, during which time they undergo
chemical conversion into acids (sulphuric and nitric). These pollutants, together with their reaction
products, affect the chemical composition of the soil and the surface water. This process interferes
with ecosystems, leading to what is called "acidification". The decline of forests in Central and
59
Eastern Europe and the many "dead" lakes in Scandinavia and Canada are examples of damage that
are partly due to acidification.
By the end of the seventies, acidification was widely recognised as a major threat to the
environment. As a result research programmes were set up to investigate the acidification process
and to evaluate mitigation measures. These measures were included in international agreements
with explicit objectives for reducing emissions of pollutants leading to acidification.
An "acidification potential" was calculated by taking into account the number of H+ ions that can
be released by each acid molecule. The coefficients used are:
1 mole of SO2 (64.06 g) forms 2 moles of H+. Its acidification potential is consequently 31.5
mmol H+/g.
1 mole of NO2 (46 g) forms 1 mole of H+. Its acidification potential is consequently 21.5
mmol H+/g.
1 mole of NH3 (17 g) forms 1 mole of H+. Its acidification potential is consequently 59
mmol H+/g.
Results
Since NH3 and SO2 were only measured by one laboratory, the mean value was calculated on three
vehicles only (Figure 56):
18
NH3
SO2
NOx
14
+
Acidification potential (mmolH eq/km)
16
12
10
8
6
4
2
0
Diesel
Petrol
LPG
Figure 56: Acidification potential – CADC.
The high acidification potential of Diesel vehicles results from their high NOx emissions. The very
low contribution of SO2 to this acidification potential, due to the low sulphur content of the fuels
60
used for this programme, can be observed. The acidification potential is higher for LPG than for
petrol, as a consequence of higher NH3 emissions.
Summary
The acidification potential is calculated according to NH3, NOx and SO2 emissions and represents
the impact of exhaust emissions on atmospheric phenomenon such as acid rains.
Thanks to their low NOx emission level, spark-ignition vehicles (petrol and LPG) have a
significantly lower acidification potential than diesel vehicles.
3.3.4
Climate change
In order to evaluate the impact of each technology on long-term climate change, 2 indices were
calculated:
• the "Global Warming Potential", calculated according to the CO2, N2O and CH4 emission
levels,
• the "Well to Wheel" CO2 emissions inventory
3.3.4.1 Global Warming Potential
Background
Gases in the atmosphere can contribute to the greenhouse effect both directly (when the gas itself is
a greenhouse gas) and indirectly (through a chemical transformation of the gas into a greenhouse
gas). The greenhouse effect is the process which limits heat losses through the stratosphere. The
concept of a Global Warming Potential (GWP) was developed to compare the ability of each
greenhouse gas to trap heat in the atmosphere.
"The GWP of a greenhouse gas is defined as the ratio of the time-integrated radiative force from
the instantaneous release of 1 kg of a trace substance relative to that of 1 kg of a reference gas"
(IPCC 2001). The reference gas used is CO2, and therefore GWP weighted emissions are measured
in mass of CO2 equivalents.
The 100-year GWPs recommended by the IPCC (Intergovernmental Panel on Climate Change)
were used in this report (IPCC 2001). GWP values of the emissions recorded in the programme are
listed in Table 3.
Gas
CO2 (Carbon Dioxide)
CH4 (Methane)
N2O (Nitrous oxide)
Global Warming Potential
1
23
296
Table 3: global warming potential (GWP), IPCC 2001
Greenhouse gases with relatively long atmospheric lifetimes (e.g., CO2, CH4, N2O, HFCs, PFCs,
and SF6) tend to be evenly spread in the atmosphere, and consequently global average
61
concentrations can be determined. According to IPCC, gases such as water vapour, carbon
monoxide, tropospheric ozone, other ambient air pollutants (e.g., NOx, and NMVOCs), and
tropospheric aerosols (e.g.,SO2 products and black carbon) cannot be taken into account due to
their limited lifetime or their highly variable spatial concentration.
Results
N2O emissions are generally very low (below 10 ppm)(see Figure 57) and often under the detection
limit:
7.00
5.99
6.00
Number of data :
Diesel : 6
Petrol : 6
LPG : 6
LPG/Diesel : -67.0%
LPG/Petrol : -7.4%
4.00
3.00
1.98
2.14
N2O (mg/km)
5.00
2.00
1.00
0.00
Diesel
Petrol
LPG
Figure 57: N2O emissions - CADC.
Consequently, their contribution to global warming is limited in spite of their high potential (296).
CH4 emission levels lead to the same conclusion.
CO2 is therefore the main contributor of vehicle emissions to global warming. Therefore, Figure 58
roughly reflects Figure 30.
62
GWP (2001) (gCO2/km equ)
160.0
Number of data :
Diesel : 6
Petrol : 6
LPG : 6
162.5
160.3
180.0
178.9
200.0
LPG/Diesel : +1.4%
LPG/Petrol : -9.2%
140.0
120.0
100.0
80.0
60.0
40.0
20.0
0.0
Diesel
Petrol
LPG
Figure 58: Global Warming Potential (2001) - CADC.
Summary
The Global Warming Potential is calculated according to CO2, N2O and methane and represents the
impact of exhaust gases on the greenhouse effect. Due to the low emission level of N2O and
methane in comparison with CO2, the GWP is strongly linked to the CO2 emission level. Therefore,
the same conclusion can be drawn as in section 3.2.2: LPG vehicles rank between petrol and diesel
vehicles and are roughly equivalent to diesel vehicles.
3.3.4.2 Life Cycle Assessment
Background
In a common misconception, people tend to only focus on a fuel’s energy use or emission when it
is burned or otherwise consumed in vehicle engines. The same misconception applies to
considerations of fuel safety and fuel cost. Too little attention is devoted to the technology or the
infrastructure that helped create the fuel and got it to the vehicle’s tank. By contracts, a fair
comparison of automotive fuels must take into account the fuel’s entire history, from raw material
to energy output. For example, fuels that show very low pollutant emissions from the vehicle may
have high emissions during their production phases. Fuels that are very suitable for use in
combustion engines may be difficult and costly to transport and store. A fuel’s history resides in the
complete “well-to-wheel” fuel chain. The chain has five stages: feedstock production, feedstock
transportation, fuel production, fuel distribution and, finally, vehicle use. This study looks
consistently at the entire chain to examine all the aspects of fuel production and use, including
feedstocks, energy consumption, emissions, safety, technology, costs and infrastructure [16].
63
Very little information is available for Life Cycle Assessments of LPG. The most widely used
model was developed by the Argonne Laboratory (“Transportation cycle model” - GREET 1.5 –
August 1999), which gave a value for LPG production of 7.5 gCO2/MJ (LPG produced in
reffinery).
As far as petrol and diesel are concerned, more values can be found, giving variable results:
Source
Source
Source
"ADEME": low
"ADEME": Euro
"CONCAWE /
sulphur fuels [19]
2005 fuels [19]
EUCAR / JRC"
[18]
Petrol
13.2
12.5
10.4
10
Diesel
10.4
14.2
6.45
7.86
Low sulphur fuels Low sulphur fuels
50 ppmS fuels
Low sulphur fuels
(< 10 ppm)
(< 10 ppm)
(< 10 ppm)
The "GM" and "CONCAWE / EUCAR /JRC" studies present results for a "LPG-type" vehicle.
Nevertheless, this fuel, called "Naphtha" is designed to be used as a fuel for fuel cells and not in
internal combustion engines. It is consequently difficult to use these values in our case.
Source "GM" [17]
For each tested vehicle, the global warming potential, as calculated in section 3.3.4.1, was added to
these values in order to get the global Well-to-Wheel balance.
A constant value has been taken into account for LPG (7.5 gCO2/MJ) and compared to the 4 values
described in the table above.
64
W-to-W GHG emissions (geq CO2/km)
220
210
200
190
GM
CONCAWE
65
LPG / Petrol :
-5.9%
ADEME 1
LPG / Diesel :
+6.8%
LPG
Diesel
Petrol
Figure 60: Mean Well to Wheel CO2 emissions - CADC.
LPG / Petrol :
-11.5%
LPG / Petrol :
-11.1%
LPG / Diesel :
+8.7%
LPG / Petrol :
-13.6%
LPG
Diesel
Petrol
LPG / Petrol :
-5.5%
ADEME 1
LPG / Diesel :
+0.4%
CONCAWE
LPG / Diesel :
+2.2%
LPG / Diesel :
-0.8%
200
LPG / Petrol :
-8.2%
GM
LPG / Diesel :
-6.8%
210
LPG / Petrol :
-14.3%
220
LPG / Petrol :
-8.9%
180
LPG / Diesel :
+3.6%
190
LPG / Diesel :
-2.6%
W-to-W GHG emissions (geq CO2/km)
Results
220
ADEME 2
210
200
190
180
170
170
160
160
150
150
140
140
130
130
120
120
ADEME 2
Figure 59: Mean Well to Wheel CO2 emission - NEDC.
220
210
200
190
180
180
170
170
160
160
150
150
140
140
130
130
120
120
This calculation shows that the global balance of GHG emissions of LPG is close to that of diesel
vehicles. On the CADC ("real-life" cycle), sometimes the global GHG emission level is even lower
than the one found for diesel engines.
Summary
Well to Wheel studies allow a more precise evaluation of the impact of each technology on
the greenhouse effect by taking into account the global fuel production pathway. Very little
data is available for LPG. Nevertheless, with the values used (Greet 1.5 model), LPG presents
a WtoW GHG balance close to what is calculated for diesel vehicles, regardless of the source
considered for petrol and diesel data.
66
3.4 Comparison with alternative technologies / fuels
Two vehicles, representing alternative technologies, were tested and the results compared with
those of diesel and where possible petrol and LPG,:
- a diesel vehicle equipped with DPF
- a vehicle running on natural gas.
As far as the CNG vehicle was concerned, the same vehicle model was tested in petrol, diesel and
LPG versions. The comparison is therefore direct.
As far as the DPF vehicle was concerned, the corresponding petrol and LPG vehicles were not
tested. Consequently, no direct comparison can be done.
It should be underlined that few pollutant emissions were measured on the CNG and DPF vehicles.
Therefore, few environmental or health indexes were calculated.
3.4.1 Diesel vehicle equipped with DPF
In order to reduce the PM emissions of diesel vehicles, the most promising way seems to be the use
of DPF (Diesel Particulate Filter). This technology reduces PM emissions through continuous
burning or sequential treatment (storage / regeneration).
The results obtained on particulate mass on the tested vehicle are presented in the Figure 61:
0.060
emissions (g/km)
0.050
0.040
0.030
0.020
0.010
0.000
cold NEDC
hot NEDC
CADC
Urban
CADC Road
CADC
Motorway
Euro 3
Euro 4
Figure 61: PM measurements - vehicle with DPF.
All the measured particulate masses were below 5 mg/km on all the tested cycles. For instance, on
the NEDC, the emission level is around 2 mg/km, which is below the quantification limit of the
technique.
67
This considerable reduction of particulate mass emissions induces a decrease of some
environmental indices. For instance, it was outlined that cancer potency values were mainly linked
to the particulate mass. Consequently, the use of DPF will lead to a big drop in this parameter
which is at the same level as that of LPG or petrol.
As far as the other emissions are concerned, no comparison can be done since the corresponding
petrol and LPG vehicles were not tested. Especially, the impact of DPF on CO2 emissions cannot
be precisely evaluated.
3.4.2 CNG vehicle
A vehicle was tested in its diesel, petrol, LPG and CNG versions. The results obtained for diesel,
petrol and LPG were included in the database and have been assessed in the previous section.
3.4.2.1 Regulated pollutant emissions
0.8
1.8
LPG / Diesel : +81.5%
LPG / Petrol : -27.9%
LPG / CNG : +35.4%
0.7
1.4
0.6
1.2
0.5
CO (g/km)
CO (g/km)
LPG / Diesel : x 130.0
LPG / Petrol : +173.8%
LPG / CNG : x 7.3
1.6
0.4
0.3
1
0.8
0.6
0.2
0.4
0.1
0.2
0
0
Diesel
Petrol
LPG
CNG
Diesel
Petrol
LPG
CNG
Figure 62: CO emissions – NEDC (left) and CADC (right).
0.06
0.014
LPG / Diesel : -0.0%
LPG / CNG : -21.6%
0.05
0.01
HC (g/km)
0.04
HC (g/km)
LPG / Petrol : x 6.3
LPG / CNG : -51.4%
0.012
0.03
0.02
0.008
0.006
0.004
0.01
0.002
0
0
Diesel
Petrol
LPG
CNG
Diesel
Petrol
Figure 63: HC emissions – NEDC (left) and CADC (right).
68
LPG
CNG
0.5
1
LPG / Petrol : n.s.
LPG / CNG : n.s.
0.45
0.4
0.8
0.7
NOx (g/km)
0.35
NOx (g/km)
LPG / Petrol : n.s.
LPG / CNG : n.s.
0.9
0.3
0.25
0.2
0.6
0.5
0.4
0.15
0.3
0.1
0.2
0.05
0.1
0
0
Diesel
Petrol
LPG
CNG
Diesel
Petrol
LPG
CNG
Figure 64: NOx emissions – NEDC (left) and CADC (right).
0.014
0.03
LPG / Petrol : LPG / CNG : -
0.012
0.025
0.01
0.02
PM (g/km)
PM (g/km)
LPG / CNG : -
0.008
0.006
0.015
0.01
0.004
0.005
0.002
0
0
Diesel
Petrol
LPG
CNG
Diesel
Petrol
LPG
CNG
Figure 65: PM emissions – NEDC (left) and CADC (right).
As far as regulated pollutant emissions are concerned, the following conclusions can be drawn on
CNG vehicle:
- CO emissions have an intermediate level between diesel and petrol vehicles. The fact
that the CNG vehicle has higher CO emissions than the corresponding diesel vehicle
seems surprising and could be explained by injector tightness factors.
- HC emissions are very low for the four technologies. No significant conclusions can
consequently be drawn.
- NOx emissions are very low.
- As far as particulates are concerned, the lack of measurement does not enable any
comparison.
69
3.4.2.2 CO2 emissions
240
250
LPG / CNG : +6.6%
230
LPG / CNG : +18.0%
200
CO2 (g/km)
CO2 (g/km)
220
210
200
150
100
190
50
180
170
0
Diesel
Petrol
LPG
CNG
Diesel
Petrol
LPG
CNG
Figure 66: CO2 emissions - NEDC and CADC.
CO2 emissions from the CNG vehicle are equivalent to those measured in diesel. On the CADC, the
emission level is even lower. CNG can consequently have a very positive impact on greenhouse
gases emissions.
3.4.2.3 Unregulated pollutant emissions
0.6
LPG / Diesel : LPG / Petrol : -100.0%
LPG / CNG : -100.0%
0.045
0.04
Acetaldehyde (mg/km)
0.5
Formaldehyde (mg/km)
0.05
LPG / Diesel : LPG / Petrol : LPG / CNG : -100.0%
0.4
0.3
0.2
0.035
0.03
0.025
0.02
0.015
0.01
0.1
0.005
0
0
Diesel
Petrol
LPG
CNG
Diesel
Petrol
LPG
CNG
Figure 67: formaldehyde and acetaldehyde emissions - CADC.
The formaldehyde emissions at the exhaust of the CNG vehicle are much higher than for the other
technologies (above detection limits), due to a partial oxidation of methane during combustion. As
far as acetaldehyde are concerned, CNG leads to a drop in emissions compared to petrol engines.
No values can be reported for diesel and LPG engines, due to low emission levels.
70
0.45
0.12
LPG / CNG : x 7.0
0.4
LPG / CNG : -
0.1
toluene (mg/km)
benzene (mg/km)
0.35
0.3
0.25
0.2
0.15
0.08
0.06
0.04
0.1
0.02
0.05
0
0
Diesel
Petrol
0.014
CNG
Diesel
Petrol
0.6
LPG / CNG : -100.0%
0.012
0.01
0.008
0.006
0.004
LPG
CNG
LPG / CNG : x 3.5
0.5
BTX (mg/km)
p,m-xylene (mg/km)
LPG
0.4
0.3
0.2
0.1
0.002
0
0
Diesel
Petrol
LPG
CNG
Diesel
Petrol
LPG
CNG
Figure 68: BTX emissions - CADC.
The BTX emissions for gaseous fuels (LPG and CNG) are low in comparison with diesel and
gasoline vehicles, due to their very low aromatic compound content.
3.4.2.4 Summary
The results obtained with the single CNG vehicle show a lower emission of most of the pollutant
measured in comparison with diesel, but also with spark-ignition engines (petrol and LPG).
However no general conclusion can be drawn on this fuel as only one vehicle has been tested and
as not all measurement and relevant calculation have been made.
3.4.3
Big van
3.4.3.1 Background
Environmental issues are more acute in urban areas. In these areas, pollutant emissions can be
linked to emissions of passengers cars, but also utility vehicles running in a "parcel delivery" mode
and consequently inducing high emissions. Therefore, since most of these vehicles are diesel, the
test of such a vehicle in LPG can give important information.
The chosen vehicle, a big van with a mass of 1900 kg, was tested in its diesel, petrol and LPG
versions.
Since this van is used for the carriage of goods, it complies with the Euro 3 and Euro 4 limits in the
"N1" category (maximum weight not exceeding 3.5 tonnes), in the reference mass category III
(reference weight > 1760 kg). These limits are summarised in the section 7.2.
71
3.4.3.2 Test results
The main results on pollutant emissions are summarised in the Figure 69 (NEDC) and Figure 70
(CADC):
1.708
0.8
Diesel
Petrol
LPG
0.7
emission (g/km)
0.6
0.5
0.4
0.3
0.2
0.1
0.0
CO
HC
NOx
Part
Figure 69: Pollutant emissions - big van - NEDC
3.494
1.4
Diesel
Petrol
LPG
1.2
emission (g/km)
1.0
0.8
0.6
0.4
0.2
0.0
CO
HC
NOx
Part
Figure 70: pollutant emissions - big van - CADC
These figures show that the main conclusions on regulated pollutant emissions on this vehicle are
close to those obtained for the other vehicles:
- the NOx and particulate emissions of the diesel vehicle are significantly higher than
those obtained for spark-ignition vehicles.
- on the other hand, the CO emissions of diesel vehicles are significantly lower than those
of spark-ignition engines. The LPG vehicle is characterised by relatively high CO
emissions. Nevertheless, it should be underlined that the emissions remain within the
scope of the Euro 3 limit on NEDC (1.71 g/km, while the Euro 3 limit is 5.22 g/km)
72
As far as CO2 is concerned, the emissions from the LPG vehicle are between those of petrol and
diesel vehicles:
350
300
CO2 (g/km)
250
200
150
100
50
0
Diesel
Petrol
LPG
Figure 71: CO2 emissions - big van - NEDC
350
300
CO2 (g/km)
250
200
150
100
50
0
Diesel
Petrol
LPG
Figure 72: CO2 emissions - big van - CADC.
As far as unregulated pollutant emissions are concerned, the results obtained are comparable with
those measured on passenger cars. The results obtained for formaldehyde and BTX measurements
are presented in the following figures:
73
0.25
0.2
0.15
0.1
0.05
0
Diesel
Petrol
LPG
Figure 73: Formaldehyde emissions - big van - CADC.
The formaldehyde emissions of the diesel vehicle are higher than those measured for spark-ignition
vehicles (LPG and petrol). This variation is similar than those calculated on the passenger cars (see
Figure 35 in section 3.2.3.1).
0.9
0.8
BTX (mg/km)
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Diesel
Petrol
LPG
Figure 74: BTX emission level - big van - CADC.
BTX emissions are similar for LPG and petrol vehicles. Both are consequently higher than those of
the diesel vehicle. The CADC is a warm-start cycle. Therefore, it remains difficult to link this
higher emission level to the fact than the engine starts with petrol: the catalyst is activated and each
phase of the CADC begins with a warm-up phase with no pollutant emission measurements. This
effect remains difficult to explain.
The environmental indices were also calculated and give results similar to those calculated for
passenger cars. For instance, the TOFP and POCP values are presented in the following figures:
74
12
1.8
LPG / Petrol : x 7.3
LPG / Petrol : +143.4%
1.6
TOFP (gNMVOC eq/km)
POCP (g eq ethene/km)
10
8
6
4
1.4
1.2
1
0.8
0.6
0.4
2
0.2
0
0
Diesel
Petrol
Diesel
LPG
Figure 75: POCP level - big van - CADC.
Petrol
LPG
Figure 76: TOFP level - big van - CADC.
3.4.3.3 Summary
In order to obtain data on delivery vehicles, a big van was analysed in the context of this study.
Diesel, petrol and LPG versions were tested.
The measurements of regulated and unregulated pollutant emissions, like environmental indices,
gave results close to those obtained on passenger cars.
75
4 Summary of main results obtained
The following tables and diagrams summarise the main impact of LPG.
4.1.1 Tables
In each case, the increase or decrease of the parameter compared with diesel or petrol has been
quantified. The reliability of the comparison was also tabulated ("high rel.", "average rel." or "low
rel.") estimated according to the measurement reliability, the number of vehicles tested, the
reliability or the calculation method…
CO
HC
NOx
PM
CO2
NO2
MSAT
(Mobile
Source
Toxics,
defined
EPA)
Formaldehyde
Acetaldehyde
Air- Benzene
as 1,3-butadiene
by PAH Total
"2A"
"2B"
Cancer Unit Risk Index
LPG versus Diesel
Regulated pollutant emissions
↑↑↑ (high rel.)
↑↑ (low rel.)
↓↓↓ (high rel.)
↑ (high rel.)
LPG versus petrol
↓↓ (high rel.)
↓↓↓ (average rel.)
↑ (low rel.)
n.s.
-
~ (high rel.)
~ (average rel.)
~ (average rel.)
↓↓ (low rel.)
n.s.
-
-
-
-
-
-
-
POCP
TOFP
Acidification Potential
Global Warming
(2001)
Well to Wheel CO2
Potential
↑ (high rel.)
~ (low rel.)
↓↓ (high rel.)
n.s.
↓ (high rel.)
Table 4: Summary of the results obtained on the NEDC
76
LPG versus petrol
CO
HC
NOx
PM
LPG versus Diesel
Regulated pollutant emissions
↑ (average rel.)
↓↓↓ (high rel.
CO2
~ (high rel.)
↓↓ (high rel.)
↓↓ (high rel.)
↓↓ (average rel.)
n.s.
↓↓ (low rel.)
↓↓ (low rel.)
↓↓↓ (low rel.)
~ (high rel.)
↓↓ (average rel.)
n.s.
↓↓ (low rel.)
↓↓ (high rel.)
~ (high rel.)
↓↓ (high rel.)
↑↑↑ (low rel.)
~ (high rel.)
↓↓ (high rel.)
~ (low rel.)
↓↓ (low rel.)
NO2
MSAT
(Mobile
Source
Toxics,
defined
EPA)
Formaldehyde
Acetaldehyde
Air- Benzene
as 1,3-butadiene
by PAH Total
"2A"
"2B"
Cancer Unit Risk Index
POCP
TOFP
Acidification Potential
Global Warming
(2001)
Well to Wheel CO2
Potential
↑↑ (high rel.)
↑↑ (average rel.)
n.s.
Table 5: Summary of the results obtained on the CADC
4.1.2
Diagrams
The diagrams below show, for the main emissions (NOx, CO, HC, Particulates and CO2), the
respective levels of each type of vehicle (petrol, LPG and diesel). Error bars are calculated
according to the 95% confidence interval by including all the vehicles.
77
1.4
2.5
LPG
Petrol
Diesel
1.2
LPG
Petrol
Diesel
2
CO (g/km)
CO (g/km)
1
0.8
0.6
1.5
1
0.4
0.5
0.2
0
0
0
0.02
0.04
0.06
0.08
0.1
0
0.12
0.005
0.01
0.015
0.02
HC (g/km)
HC (g/km)
0.04
0.06
LPG
Petrol
Diesel
0.035
0.03
LPG
Petrol
Diesel
0.05
PM (g/km)
PM (g/km)
0.04
0.025
0.02
0.015
0.03
0.02
0.01
0.01
0.005
0
0
0
0.1
0.2
0.3
0.4
0
0.5
0.2
0.4
NOx (g/km)
210
0.8
1
200
LPG
Petrol
Diesel
200
190
1.2
LPG
Petrol
Diesel
190
180
180
CO2 (g/km)
CO2 (g/km)
0.6
NOx (g/km)
170
160
170
160
150
150
140
140
130
130
120
120
0
0.1
0.2
0.3
0.4
0
0.5
0.2
0.4
0.6
0.8
1
1.2
NOx (g/km)
NOx (g/km)
Table 6 : Comparison of main emissions for Petrol, LPG and diesel on the NEDC (left) and
CADC (right).
3
LPG
Petrol
Diesel
0.4
2.5
0.45
LPG
Petrol
Diesel
2
1.5
1
0.5
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
0
0
0.5
1
1.5
2
2.5
3
3.5
4
0
0.2
0.4
0.6
0.8
1
1.2
1.4
Table 7 : Comparison of main unregulated emissions for petrol, LPG and diesel on the
CADC.
78
5 Main conclusion
Fuels and engines used in road transportation have to face two main challenges in a highly
competitive economy:
• the reduction of pollutant emission levels to such values that air quality in cities complies with
World Health Organisation standards
• the reduction of carbon dioxide emissions (CO2), considered as being the major greenhouse gas
contributing to global warming and climate change.
Among the technical solutions available to face up to these two challenges, the use of automotive
LPG deserved to be further investigated. Indeed, the potential of this gas to reduce CO2 emissions
is important due to its high H/C ratio. Moreover, its simple chemical composition seems a
promising way to reduce the emissions of some significant pollutant.
In order to compare the emission levels of vehicles currently sold in Europe, which run on each of
the three fuels - diesel, petrol or LPG - the programme designed to update data on regulated and
non regulated emissions was developed by the LPG industry and environmental /governmental
bodies, all over Europe and implemented in four laboratories.
This programme also aimed at assessing the relative impact of these fuels on the air quality in terms
of health and greenhouse effects.
A specific test sequence was developed on the basis of the three different driving cycles that are
representative of real-life driving conditions. A large number of vehicles sold in Europe were tested
on a pan-European basis. LPG vehicles were either produced by car manufacturers or postequipped under their control.
All the emissions, environmental index and health effect indicators have been compared between
each fuel, allowing a more accurate comparison of each technology advantages and drawbacks
The main conclusions are:
•
as far as pollutant emissions are concerned, LPG vehicles have significantly lower emissions of
NOx and particulates than diesel vehicles (respectively 95% less and 90% less on the CADC).
They also have similar or lower emissions for most non-regulated pollutants compared to diesel
vehicles, especially oxygenated compounds (95% less formaldehyde, 70% less acetaldehyde)
and benzene (equivalent level LPG / diesel, but 80% less for LPG in comparison with petrol).
•
In any event, the CO2 emissions measured for LPG vehicles were much lower than those of
petrol vehicles and were close to those of diesel vehicles. In certain situations (motorway
cycle), some vehicles even have lower CO2 emissions in LPG than in diesel. It could
consequently represent a promising way to contribute to the reduction of CO2 emissions.
•
The environmental and health effect indicators calculated showed that exhaust emissions from
LPG vehicles had lower cancer index (mainly linked to the lower particulate emission level),
acidification potential (due to their lower NOx emission level) and regional ozone forming
potential (TOCP) than diesel vehicles
79
Some points still remain to be optimised, such as :
•
CO emissions, that remain higher for LPG vehicles
•
HC emissions, which for LPG vehicles are equal compared to petrol on NEDC but slightly
increased on CADC.
•
As far as ozone formation is concerned, the above-mentioned conclusion should be mitigated
when considering the local ozone forming potential (POCP) which is higher for LPG vehicles.
Moreover, in terms of cancer index, the level of LPG and petrol vehicles can be joined by the
diesel ones if equipped with the DPF (Diesel Particulate Filter).
The programme also has shown that LPG engine map tuning is one of the key elements influencing
pollutant emissions.
Consequently, as long as precise ECU calibration is done, LPG vehicles can be seen as a promising
way to further reduce the main pollutant emissions, especially :
NOx,
Particulates (LPG vehicles are however at the level of the most modern diesel technologies
eg: DPF),
Concerning CO and HC it seems that progress can be done with a relevant development on
mapping on ECU.
Mobile Source Air Toxics (MSAT)
while limiting the increase in CO2 emissions.
80
6 References
[1] ACEA's CO2 Commitment (05/12/2002), http://www.acea.be/ACEA/brochure_CO2.pdf
[2] "Health Aspects of Air Pollution with Particulate Matter, Ozone and Nitrogen Dioxide", Report
on a WHO (World Health Organization) Working Group, Bonn, Germany, 13-15 January 2003
[3] "Health Effect of Aldehydes and Alcohols in Mobile Source Emissions", in "Air Pollution, The
Automobile and Public Health", 1988, The National Academy of Sciences.
[4] Schulz, H., Brand, P., and Heyder, J. (2000). Particle deposition in the respiratory tract. In
Particle-lung interactions (J. H. Peter Gehr, eds.), pp. 229-290. Marcel Dekker, Inc, New-York.
[5] "Human Respiratory Tract Model for Radiological Protection", Annals of the ICRP, volume 24,
ICRP publication 66.
[6] "Characterization of Exhaust Particulate Emissions From Road Vehicles", Z. Samaras, L.
Ntziachristos, B. Giechaskiel, Paper presented at the FISITA 2002 conference, June 2-7 2002,
Helsinki, Finland
[7] Jeuland N., Dementhon J.B., Momique J.C, Belot G., Plassat G., Corroler P., Bruchet D.,
"Performances and durability of DPF (diesel particulate filter) tested on a fleet of Peugeot 607
Taxis~First and second test phases results", SAE 2002-01-2790.
[8] Formaldehyde, ENVIRONMENTAL HEALTH CRITERIA 89, 1989, WHO (World Health
Organisation)
[9] Acetaldehyde, ENVIRONMENTAL HEALTH CRITERIA 1679, 1995, WHO (World Health
Organisation)
[10]: "Nitrogen Dioxide: Evaluation of current California Air Quality Standards with respect to
protection of Children", California Office of Environmental Health Hazard Assessment
[11] William P. L. Carter: "DEVELOPMENT OF OZONE REACTIVITY SCALES FOR
VOLATILE ORGANIC COMPOUNDS", Journal of the Air and Waste Management Association,
Vol 44, pages 881-899, 1994
[12] M.E. Jenkin & al: "Protocol for the development of the Master Chemical Mechanism, MCM
v3 (part A): tropospheric degradation of non-aromatic volatile organic compounds", Atmos. Chem.
Phys., 3, 161-180, 2003
[13] M.E. Jenkin & al: "Protocol for the development of the Master Chemical Mechanism, MCM
v3 (part A): tropospheric degradation of aromatic volatile organic compounds", Atmos. Chem.
Phys., 3, 181-193, 2003
[14] EPEFE: "European Programme on Emissions, Fuels and Engine Technologies", ACEA
Europia
81
[15] "Cancer Risk Ranking of HD vehicles - Comparison between diesel fuels and CNG using
different unit risk factors" - Ecotraffic ERD, August 2000.
[16] "Automotive Fuels for the Future - The search for Alternative" - report from IAE
(International Energy Agency).
[17] GM Well-To-Wheel Analysis of Energy Use and Greenhouse Gas Emissions of Advanced
Fuel / Vehicle Systems - A European Study", L-BlSystemtechnik GmBH, September 2002.
[18] "Well-To-Wheels analysis of Future automotive fuels and powertrains in the European
context", CONCAWE, EUCAR, JRC, December 2003
[19] "bilans énergétiques et gaz à effet de serre des filières de production de biocarburants en
France", ADEME, DIREM, September 2002
82
7 Appendices
83
7.1 Fuel analysis
Density (15°C)
PVSE
Distillation:
IBP
5%
10%
20%
30%
40%
50%
60%
70%
80%
90%
95%
FBP
Residue
Losses
E100
E150
Composition
Saturates
Olefins
Aromatics
Oxygenates
Benzene
Octane
RON
MON
Oxidation stability
Existent Gum
Sulfur content
Phosphorus content
Lead content
Copper Corrosion 3h, 50°C
C/H Ratio
Calorific Value
%C
%H
%O
method
EN ISO 3675
EN 13016-1
Result
751
600
Unit
kg/m3
mbar
EN ISO 3405
38
46
51
57
65
77
93
109
122
141
171
185
194
1
1.8
55.6
84.4
°C
°C
°C
°C
°C
°C
°C
°C
°C
°C
°C
°C
°C
%(V/V)
%(V/V)
%(V/V)
%(V/V)
ASTM D1319-95
EN 12177-98
53.4
7.9
32.6
6.1
0.5
%(V/V)
%(V/V)
%(V/V)
%(V/V)
%(V/V)
EN 25164-93
EN 25163-93
96.8
86
EN ISO 7536
EN ISO 6246
EN ISO 20846
ASTM D3231
EN 237-96
ISO 2160
GPC
>480
min
<4
mg/100 ml
64
mg/kg
<0.0013
g/l
<0.005
g/l
<1
6.53
10119
kcal/kg
85.8
%(m/m)
13.1
%(m/m)
1.06
%(m/m)
Table 8: petrol analysis.
84
Characteristics
Density @ 15°C
Flash Point
Cloud Point
Pour Point
Cold Filter Plugging Point
Acidity index
Sulfur content
Viscosity @ 20°C
Viscosity @ 40°C
Water content
Ashes
Conradson Carbon residue
Gross Heating Value
Net Heating Value
Distillation
Initial Point
5%
10%
20%
30%
40%
50%
60%
70%
80%
90%
95%
Final Point
Distillated fraction
Residue
Losses
Elementary Analysis
Carbon
Hydrogen
Oxygen
H/C ratio
O/C ratio
Chemical composition
Aromatics
Saturated compounds
Measured Cetane number
Method
EN ISO 3675
EN 22719
EN 23015
EN 116
ASTM D664
EN ISO 14596
EN ISO 3104
EN ISO 3104
EN ISO 12937
EN ISO 6245
EN ISO 10370
ASTM D240
Calculated
EN ISO 3104
ASTM D5291
ESTM D 5622
Calculated
Calculated
EN ISO 5165
Result
841.9
85.5
1
-9
-7
0.02
35
6.187
3.731
163
< 0.01
0.050
45970
43130
Unit
kg/m3
°C
°C
°C
°C
gKOH/g
mg/kg
mm2/s
mm2/s
% mg/kg
% weight
% weight
kJ/kg
kJ/kg
200.6
228.9
245.2
261.3
274.7
284.7
294.0
303.1
313.5
326.0
343.3
358.2
364.2
97.6
1.6
0.7
°C
°C
°C
°C
°C
°C
85.87
13.46
0.35
1.87
0.0031
% m/m
%
%
29.60
70.40
%(v/v)
%(v/v)
54.8
Table 9: Diesel fuel analysis.
85
°C
°C
°C
°C
°C
°C
% volume
% volume
% volume
Test
Composition
Ethane
Propane
Propene
Iso-butane
n-butane
trans-but-2-ene
but-1-ene
iso-butene
cis-but-2-ene
iso-pentane
n-pentane
Total Olefins
Vapour pressure @ 40°C
Vapour pressure @ -5°C
Vapour pressure @ -10°C
Water
Water
Water
Total sulphur
Hydrogen sulphide
Residue on evaporation
MON
Copper Corrosion
Odour
Composition
Ethane
Propane
Propene
Iso-butane
n-butane
trans-but-2-ene
but-1-ene
iso-butene
cis-but-2-ene
iso-pentane
n-pentane
Total Olefins
Method
ISO 7941
Result
0.2
62.7
0.1
11.9
24.7
0.1
0.1
0.2
ISO 8973/C
ISO 8973/C
ISO 8973/C
Visual
Moist Anal
Dewpoint
EN 24260
ISO 8819
EN ISO 13757
EN 589
ISO 6251
EN 589
ISO 7941
0.3
917
195
151
No free water
40
25
9
Neg
6
93.8
1
Normal
0.1
56.1
0.1
14
29.1
0.1
0.1
0.3
0.3
Table 10: LPG analysis.
86
Unit
%(mol/mol)
%(mol/mol)
%(mol/mol)
%(mol/mol)
%(mol/mol)
%(mol/mol)
%(mol/mol)
%(mol/mol)
%(mol/mol)
%(mol/mol)
%(mol/mol)
%(mol/mol)
kPa
kPa
kPa
mg/kg
mg/kg
mg/kg
mg/kg
%(m/m)
%(m/m)
%(m/m)
%(m/m)
%(m/m)
%(m/m)
%(m/m)
%(m/m)
%(m/m)
%(m/m)
%(m/m)
%(m/m)
7.2 Current and Future regulations
A summary of current (Euro 3 – 2000) and future (Euro 4 – 2005) pollutant emissions regulations
is presented in the Table 11 and Table 12.
Tier
Year
Diesel
Euro 3
2000.01
Euro 4
2005.01
Petrol (Gasoline)
Euro 3
2000.01
Euro 4
2005.01
CO
HC
HC+NOx
NOx
PM
0.64
0.50
-
0.56
0.30
0.50
0.25
0.05
0.025
2.30
1.0
0.20
0.10
-
0.15
0.08
-
Table 11: EU Emission Standards for Passenger Cars, g/km
Class
Tier
Year
CO
HC
HC+NOx NOx
PM
Euro 3
Euro 4
Euro 3
Euro 4
Euro 3
Euro 4
2000.01
2005.01
2002.01
2006.01
2002.01
2006.01
0.64
0.50
0.80
0.63
0.95
0.74
-
0.56
0.30
0.72
0.39
0.86
0.46
0.50
0.25
0.65
0.33
0.78
0.39
0.05
0.025
0.07
0.04
0.10
0.06
Euro 3
Euro 4
Euro 3
Euro 4
Euro 3
Euro 4
2000.01
2005.01
2002.01
2006.01
2002.01
2006.01
2.3
1.0
4.17
1.81
5.22
2.27
0.20
0.1
0.25
0.13
0.29
0.16
-
0.15
0.08
0.18
0.10
0.21
0.11
-
Diesel
N1, Class I <1305 kg
N1, Class II 1305-1760 kg
N1, Class III >1760 kg
Petrol (Gasoline)
N1, Class I <1305 kg
N1, Class II 1305-1760 kg
N1, Class III >1760 kg
Table 12: EU Emission Standards for Light Commercial Vehicles, g/km
87
7.3 List of vehicles tested
The following table gives an overview of the participating vehicles
No.
Model Nr
1
Name
Capacity cm3
power kW
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
Vauxhall Vectra Bi-fuel
1800 (90 kW)
Vauxhall Vectra Petrol
1800 (90 kW)
Vauxhall Vectra DTi
2000 (74 kW)
2
Vauxhall Astra Bi-fuel
1600 (62 kW)
Vauxhall Astra Petrol
1600 (62 kW)
Vauxhall Astra diesel
1700 (55 kW)
3
Peugeot 406 Bi-fuel
1800 (80 kW)
Peugeot 406 petrol
1800 (80 kW)
Peugeot 406 HDi
2000 (80 kW)
4
Renault Scenic Bi-fuel
1600 (76 kW)
Renault Scenic petrol
1600 (76 kW)
Renault Scenic DCi
1900 (75 kW)
5
Volvo V40 Bi-fuel
1800 (88 kW)
Volvo S40 petrol mono
1800 (90 kW)
Volvo V40 Diesel
1900 (85 kW)
6
Volvo V70 Bi-fuel
2400 (103 kW)
Volvo V70 petrol
2400 (103 kW)
Volvo V70 Diesel
2400 (120 kW)
7
Nissan Primera Bifuel
1800 (85 kW)
Nissan Primera petrol
1800 (85 kW)
Nissan Primera 2.2D
2200 (93 kW)
8
Vauxhall Combo Bi-fuel
1600 (64 kW)
Vauxhall Combo Diesel
1700 (55 kW)
9
Kangoo Bi-fuel
1200 (55 kW)
Kangoo Dci
1500 (48 kW)
R1
Peugeot 307 Hdi (Diesel + 2000 (79 kW)
DPF)
R2 27 Volvo V70 CNG
2400 (103 kW)
Note: the tenth model is the big van (3 vehicles)
Total: 10 models (+ 2 reference models), 30 vehicles tested
CRDI: Common-Rail Diesel Injection
PFI: Port-Fuel Injection
All the LPG were PFI gaseous injection vehicles.
88
/ Engine Type
16V 4 cylinders, PFI
16V 4 cylinders
16V 4 cylinders, CRDI
16V 4 cylinders
16V 4 cylinders
20V 5 cylinders
16V 4 cylinders
16V 4 cylinders
16V 4 cylinders
8V 4 cylinders
16V 4 cylinder
20V 5 cylinders
7.4 Tables of numerical results
7.4.1
NOx emissions
NOx emission level (NEDC)
Vehicle
Diesel
Petrol
R
0.321
0.088
Y
0.354
0.038
H
0.344
0.026
E
0.420
0.060
T
0.450
0.010
W
0.410
0.010
F
0.305
0.015
C
0.380
0.157
P
0.448
-
LPG
0.034
0.007
0.012
0.040
0.020
0.000
0.010
0.015
0.007
Variation
LPG / Diesel
LPG / Petrol
-89.3%
-61.0%
-98.2%
-82.9%
-96.6%
-55.0%
-90.5%
-33.3%
-95.6%
+100.0%
-100.0%
-100.0%
-96.6%
-29.3%
-96.1%
-90.4%
-98.4%
-
Table 13: NOx emission level (NEDC)
NOx emission level (ECE cycle)
Vehicle
Diesel
Petrol
R
0.375
0.189
Y
0.408
0.086
H
0.322
0.048
E
0.510
0.135
T
0.530
0.022
W
0.520
0.020
F
0.381
0.030
C
0.371
0.054
P
0.478
-
LPG
0.078
0.008
0.025
0.100
0.030
0.010
0.019
0.016
0.014
Variation
LPG / Diesel
LPG / Petrol
-79.1%
-58.5%
-97.9%
-90.1%
-92.3%
-47.9%
-80.4%
-25.8%
-94.3%
+36.6%
-98.1%
-50.0%
-95.1%
-38.1%
-95.7%
-70.4%
-97.1%
-
Table 14: NOx emission level (ECE cycle)
89
NOx emission level (EUDC)
Vehicle
Diesel
Petrol
R
0.289
0.028
Y
0.323
0.010
H
0.357
0.013
E
0.360
0.010
T
0.400
0.004
W
0.350
0
F
0.261
0.006
C
0.386
0.217
P
0.431
-
LPG
0.008
0.005
0.004
0.010
0.010
0
0.006
0.015
0.003
Variation
LPG / Diesel
LPG / Petrol
-97.1%
-70.8%
-98.3%
-45.0%
-98.9%
-70.6%
-97.2%
+0.5%
-97.5%
+132.2%
-100.0%
-97.9%
-1.3%
-96.1%
-93.1%
-99.2%
-
Table 15: NOx emission level (EUDC)
NOx emission level (warm NEDC)
Vehicle
Diesel
Petrol
LPG
R
0.33
0.12
0.02
Y
0.41
0.04
0.04
H
0.37
0.01
0.01
E
0.21
0.14
0.02
T
0.53
0.02
0.02
W
0.43
0.00
0.00
F
0.34
0.03
0.01
C
0.41
0.07
0.02
P
0.43
0.01
Variation
LPG / Diesel
LPG / Petrol
-95.3%
-87.1%
-90.1%
-7.3%
-97.8%
-6.9%
-91.7%
-87.6%
-96.0%
-0.1%
-99.1%
+0.3%
-97.6%
-71.0%
-95.1%
-73.0%
-98.6%
-
Table 16: NOx emission level (warm NEDC)
NOx emission level (warm ECE cycle)
Vehicle
Diesel
Petrol
LPG
R
0.39
0.28
0.03
Y
0.49
0.08
0.08
H
0.39
0.00
0.02
E
0.55
0.36
0.03
T
0.57
0.04
0.04
W
0.52
0.01
0.01
F
0.43
0.07
0.01
C
0.43
0.08
0.00
P
0.44
0.01
Variation
LPG / Diesel
LPG / Petrol
-92.0%
-88.7%
-84.7%
-4.2%
-96.0%
+283.5%
-94.5%
-91.7%
-93.0%
-0.0%
-98.1%
-0.0%
-97.2%
-82.0%
-99.3%
-96.3%
-97.5%
-
Table 17: NOx emission level (warm ECE cycle)
90
NOx emission level (warm EUDC)
Vehicle
Diesel
Petrol
LPG
R
0.30
0.03
0.01
Y
0.36
0.02
0.02
H
0.36
0.01
0.00
E
0.01
0.01
0.01
T
0.51
0.01
0.01
W
0.37
0.00
0.00
F
0.29
0.01
0.01
C
0.39
0.07
0.03
P
0.42
0.00
Variation
LPG / Diesel
LPG / Petrol
-97.9%
-77.0%
-94.5%
-12.9%
-98.9%
-65.7%
-0.0%
-0.0%
-98.0%
-0.0%
-100.0%
-97.8%
-5.6%
-92.4%
-57.1%
-99.3%
-
Table 18: NOx emission level (warm EUDC)
NOx emission level (CADC Urban cycle)
Vehicle
Diesel
Petrol
LPG
R
0.98
0.45
0.07
Y
1.14
0.23
0.26
H
0.84
0.06
0.09
E
1.25
0.13
0.14
T
1.12
0.06
0.05
W
1.02
0.05
0.01
F
0.73
0.03
0.06
C
0.83
0.34
0.05
P
0.87
0.02
Variation
LPG / Diesel
LPG / Petrol
-92.4%
-83.2%
-76.9%
+11.7%
-89.3%
+40.6%
-88.8%
+7.7%
-95.5%
-16.7%
-99.0%
-80.0%
-92.3%
+108.3%
-94.6%
-86.6%
-98.1%
-
Table 19: NOx emission level (CADC Urban cycle)
NOx emission level (CADC Road cycle)
Vehicle
Diesel
Petrol
LPG
R
0.60
0.22
0.05
Y
0.68
0.13
0.07
H
0.74
0.04
0.05
E
0.70
0.08
0.03
T
0.68
0.03
0.02
W
0.61
0.01
0.00
F
0.63
0.02
0.04
C
0.65
0.18
0.11
P
0.62
0.01
Variation
LPG / Diesel
LPG / Petrol
-92.0%
-77.9%
-89.4%
-46.5%
-93.2%
+17.2%
-95.7%
-62.5%
-97.1%
-33.3%
-100.0%
-100.0%
-93.7%
+82.2%
-82.9%
-39.0%
-98.8%
-
Table 20: NOx emission level (CADC Road cycle)
91
NOx emission level (CADC Motorway cycle)
Vehicle
Diesel
Petrol
LPG
R
0.76
0.26
0.09
Y
1.00
0.06
0.03
H
1.12
0.03
0.03
E
0.72
0.02
0.01
T
1.00
0.00
0.00
W
0.60
0.00
0.00
F
0.78
0.07
0.02
C
0.91
0.17
0.13
P
1.78
0.00
Variation
LPG / Diesel
LPG / Petrol
-87.6%
-63.6%
-97.1%
-55.2%
-97.4%
-5.5%
-98.6%
-50.0%
-100.0%
-100.0%
-98.0%
-76.3%
-86.3%
-26.9%
-99.8%
-
Table 21: NOx emission level (CADC Motorway cycle)
NOx emission level (CADC)
Vehicle
Diesel
Petrol
R
0.70
0.26
Y
0.87
0.10
H
0.92
0.04
E
0.77
0.05
T
0.89
0.02
W
0.65
0.01
F
0.70
0.04
C
0.81
0.19
P
1.24
-
LPG
0.07
0.07
0.04
0.03
0.01
0.00
0.03
0.11
0.01
Variation
LPG / Diesel
LPG / Petrol
-89.5%
-71.0%
-92.5%
-36.0%
-95.5%
+11.0%
-96.0%
-42.7%
-98.6%
-27.8%
-99.8%
-88.7%
-96.1%
-39.8%
-86.1%
-41.4%
-99.5%
-
Table 22: NOx emission level (CADC)
7.4.2
CO2 emissions
CO2 emission level (NEDC)
Vehicle
Diesel
Petrol
R
151.9
185.7
Y
148.3
166.3
H
131.7
159.0
E
161.7
197.7
T
194.4
232.5
W
138.8
179.6
F
155.9
179.9
C
168.0
183.0
P
145.6
-
LPG
171.6
149.6
137.9
175.4
210.7
161.7
161.8
157.3
159.7
Variation
LPG / Diesel
+13.0%
+0.9%
+4.7%
+8.5%
+8.4%
+16.5%
+3.8%
-6.4%
+9.7%
Table 23: CO2 emission level (NEDC)
92
LPG / Petrol
-7.6%
-10.0%
-13.3%
-11.3%
-9.3%
-9.9%
-10.0%
-14.1%
-
CO2 emission level (ECE cycle)
Vehicle
Diesel
Petrol
R
198.8
257.8
Y
189.0
211.3
H
160.1
202.3
E
214.8
280.4
T
254.9
318.4
W
186.4
248.4
F
211.6
244.5
C
218.4
244.1
P
178.4
-
LPG
235.8
188.8
175.0
249.3
288.9
220.1
219.1
205.2
216.0
Variation
LPG / Diesel
LPG / Petrol
+18.6%
-8.6%
-0.1%
-10.6%
+9.3%
-13.5%
+16.1%
-11.1%
+13.3%
-9.3%
+18.1%
-11.4%
+3.5%
-10.4%
-6.0%
-15.9%
+21.1%
-
Table 24: CO2 emission level (ECE cycle)
Vehicle
R
Y
H
E
T
W
F
C
P
CO2 emission level (EUDC)
Diesel
Petrol
124.0
143.3
124.1
139.7
114.9
133.6
130.4
148.8
159.0
182.0
110.8
139.1
123.8
141.8
138.8
147.4
126.6
-
LPG
133.8
126.6
116.1
131.9
165.0
127.5
128.5
129.3
127.8
Variation
LPG / Diesel
LPG / Petrol
+8.0%
-6.6%
+2.0%
-9.4%
+1.1%
-13.1%
+1.1%
-11.4%
+3.8%
-9.3%
+15.1%
-8.4%
+3.8%
-9.4%
-6.8%
-12.3%
+1.0%
-
Table 25: CO2 emission level (EUDC)
CO2 emission level (warm NEDC)
Vehicle
Diesel
Petrol
LPG
R
139.2
167.1
156.2
Y
134.3
155.2
139.2
H
122.6
149.9
129.2
E
149.3
181.1
159.4
T
173.5
213.4
192.4
W
124.6
165.2
150.0
F
146.2
169.0
152.1
C
152.4
169.0
147.7
P
133.0
150.2
Variation
LPG / Diesel
LPG / Petrol
+12.2%
-6.5%
+3.7%
-10.3%
+5.3%
-13.8%
+6.7%
-12.0%
+10.9%
-9.8%
+20.4%
-9.2%
+4.1%
-10.0%
-3.1%
-12.6%
+12.9%
-
Table 26: CO2 emission level (warm NEDC)
93
CO2 emission level (warm ECE cycle)
Vehicle
Diesel
Petrol
LPG
R
171.7
215.4
198.5
Y
161.4
186.2
166.3
H
142.1
180.5
155.1
E
185.2
237.2
212.0
T
211.8
274.5
245.9
W
153.9
216.4
194.1
F
181.5
222.6
200.7
C
183.2
214.3
183.7
P
150.5
195.2
Variation
LPG / Diesel
LPG / Petrol
+15.6%
-7.8%
+3.0%
-10.7%
+9.2%
-14.0%
+14.5%
-10.6%
+16.1%
-10.5%
+26.1%
-10.3%
+10.6%
-9.8%
+0.3%
-14.3%
+29.7%
-
Table 27: CO2 emission level (warm ECE cycle)
CO2 emission level (warm EUDC)
Vehicle
Diesel
Petrol
LPG
R
119.8
138.5
131.3
Y
118.2
136.8
123.3
H
111.1
131.9
113.8
E
128.4
148.0
128.6
T
151.2
177.5
161.1
W
107.4
135.0
124.0
F
125.4
137.9
124.5
C
134.3
142.4
126.5
P
122.3
125.0
Variation
LPG / Diesel
LPG / Petrol
+9.6%
-5.2%
+4.3%
-9.9%
+2.5%
-13.7%
+0.1%
-13.1%
+6.6%
-9.3%
+15.4%
-8.2%
-0.7%
-9.8%
-5.8%
-11.1%
+2.2%
-
Table 28: CO2 emission level (warm EUDC)
CO2 emission level (CADC Urban cycle)
Vehicle
Diesel
Petrol
LPG
R
250.3
273.1
246.5
Y
231.0
254.5
216.3
H
196.8
240.9
210.2
E
246.5
280.0
258.8
T
268.2
360.3
315.7
W
200.9
268.4
248.5
F
232.4
287.9
251.8
C
247.6
271.4
239.5
P
184.3
238.8
Variation
LPG / Diesel
LPG / Petrol
-1.5%
-9.7%
-6.4%
-15.0%
+6.8%
-12.8%
+5.0%
-7.6%
+17.7%
-12.4%
+23.7%
-7.4%
+8.3%
-12.5%
-3.3%
-11.7%
+29.5%
-
Table 29: CO2 emission level (CADC Urban cycle)
94
CO2 emission level (CADC Road cycle)
Vehicle
Diesel
Petrol
LPG
R
142.0
156.4
148.2
Y
140.5
144.2
130.6
H
131.7
142.4
122.5
E
153.7
169.4
151.2
T
165.0
189.3
180.6
W
121.6
155.0
142.5
F
153.8
164.9
145.5
C
157.4
155.8
140.7
P
138.4
154.4
Variation
LPG / Diesel
LPG / Petrol
+4.4%
-5.2%
-7.0%
-9.4%
-7.0%
-14.0%
-1.6%
-10.7%
+9.5%
-4.6%
+17.2%
-8.1%
-5.4%
-11.7%
-10.6%
-9.7%
+11.6%
-
Table 30: CO2 emission level (CADC Road cycle)
CO2 emission level (CADC Motorway cycle)
Vehicle
Diesel
Petrol
LPG
R
150.9
167.8
159.9
Y
163.8
176.0
160.8
H
152.7
166.2
144.1
E
170.1
174.0
154.2
T
190.3
219.7
194.8
W
136.2
159.8
152.9
F
153.3
163.5
145.2
C
179.2
180.3
159.1
P
179.1
167.5
Variation
LPG / Diesel
LPG / Petrol
+6.0%
-4.7%
-1.9%
-8.7%
-5.6%
-13.3%
-9.4%
-11.4%
+2.4%
-11.4%
+12.3%
-4.3%
-5.2%
-11.2%
-11.2%
-11.7%
-6.5%
-
Table 31: CO2 emission level (CADC Motorway cycle)
Vehicle
R
Y
H
E
T
W
F
C
P
CO2 emission level (CADC)
Diesel
Petrol
152.2
168.3
156.7
166.8
144.5
159.6
171.7
182.9
188.6
222.5
137.2
168.9
156.2
170.2
178.0
180.3
159.9
-
LPG
158.7
150.4
138.2
163.6
201.4
158.5
151.0
160.3
164.3
Variation
LPG / Diesel
LPG / Petrol
+4.3%
-5.7%
-4.0%
-9.9%
-4.3%
-13.4%
-4.7%
-10.5%
+6.8%
-9.5%
+15.5%
-6.2%
-3.4%
-11.3%
-9.9%
-11.1%
+2.7%
-
Table 32: CO2 emission level (CADC)
95
7.4.3
CO emissions
Vehicle
R
Y
H
E
T
W
F
C
P
CO emission level (NEDC)
Diesel
Petrol
0.260
0.805
0.296
0.861
0.049
0.628
0.070
0.770
0.270
0.680
0.050
0.490
0.266
0.447
0.465
1.141
0.073
-
LPG
0.711
1.812
1.231
0.710
0.490
0.550
0.519
1.525
0.684
Variation
LPG / Diesel
LPG / Petrol
+173.1%
-11.7%
x6
+110.5%
x 25
+96.2%
x 10
-7.8%
+81.5%
-27.9%
x 11
+12.2%
+95.3%
+16.2%
+228.0%
+33.7%
x9
-
Table 33: CO emission level (NEDC)
CO emission level (ECE cycle)
Vehicle
Diesel
Petrol
R
0.697
2.131
Y
0.796
2.277
H
0.132
1.611
E
0.190
1.994
T
0.720
1.447
W
0.140
0.720
F
0.660
0.942
C
1.266
2.147
P
0.193
-
LPG
1.541
4.859
3.227
1.750
1.050
1.200
0.884
2.821
1.117
Variation
LPG / Diesel
LPG / Petrol
+121.0%
-27.7%
x6
+113.4%
x 25
+100.4%
x9
-12.2%
+45.8%
-27.5%
x9
+66.7%
+33.9%
-6.2%
+122.8%
+31.4%
+477.4%
-
Table 34: CO emission level (ECE cycle)
Vehicle
R
Y
H
E
T
W
F
C
P
CO emission level (EUDC)
Diesel
Petrol
0.000
0.026
0.000
0.023
0.000
0.049
0.000
0.043
0.000
0.223
0.000
0.350
0.001
0.157
0.001
0.556
0.003
-
LPG
0.222
0.018
0.055
0.110
0.150
0.160
0.307
0.770
0.435
Variation
LPG / Diesel
LPG / Petrol
x9
-22.4%
+11.4%
+157.9%
-32.6%
-54.3%
x 307
+95.1%
x 770
+38.5%
x 133
-
Table 35: CO emission level (EUDC)
96
CO emission level (warm NEDC)
Vehicle
Diesel
Petrol
R
0.00
0.02
Y
0.03
0.09
H
0.00
0.05
E
0.00
0.44
T
0.00
0.31
W
0.01
0.56
F
0.01
0.09
C
0.03
0.55
P
0.01
-
LPG
0.41
0.22
0.08
0.33
0.11
0.15
0.30
0.57
0.20
Variation
LPG / Diesel
LPG / Petrol
x 24
x8
+144.4%
+62.9%
x 89
-24.7%
-65.0%
x 11
-72.9%
x 52
+226.5%
x 17
+3.4%
x 37
-
Table 36: CO emission level (warm NEDC)
CO emission level (warm ECE cycle)
Vehicle
Diesel
Petrol
LPG
R
0.00
0.00
0.41
Y
0.07
0.16
0.58
H
0.00
0.07
0.10
E
0.01
1.13
0.67
T
0.00
0.50
0.09
W
0.02
0.09
0.05
F
0.01
0.02
0.14
C
0.09
0.56
0.53
P
0.01
0.08
Variation
LPG / Diesel
LPG / Petrol
x8
+267.7%
+53.6%
x 67
-40.7%
-82.0%
+150.0%
-44.4%
x 14
x9
x6
-6.9%
x9
-
Table 37: CO emission level (warm ECE cycle)
CO emission level (warm EUDC)
Vehicle
Diesel
Petrol
R
0.00
0.03
Y
0.00
0.05
H
0.00
0.04
E
0.00
0.03
T
0.00
0.20
W
0.01
0.83
F
0.00
0.14
C
0.00
0.54
P
0.00
-
LPG
0.40
0.00
0.07
0.13
0.12
0.21
0.40
0.60
0.27
Variation
LPG / Diesel
LPG / Petrol
x 15
-93.2%
+71.1%
+333.3%
-40.0%
x 21
-74.7%
x 127
+189.6%
x 598
+9.9%
x 78
-
Table 38: CO emission level (warm EUDC)
97
CO emission level (CADC Urban cycle)
Vehicle
Diesel
Petrol
LPG
R
0.01
0.15
2.11
Y
0.06
0.17
0.62
H
0.00
0.20
0.26
E
0.10
0.10
0.59
T
0.13
1.26
0.44
W
0.03
0.62
1.02
F
0.03
0.27
0.11
C
0.07
2.21
2.09
P
0.01
0.77
Variation
LPG / Diesel
LPG / Petrol
x 399
x 14
x 11
+258.8%
+26.5%
+490.0%
+490.0%
+238.5%
-65.1%
x 34
+64.5%
+207.2%
-60.4%
x 30
-5.7%
x 76
-
Table 39: CO emission level (CADC Urban cycle)
CO emission level (CADC Road cycle)
Vehicle
Diesel
Petrol
LPG
R
0.00
0.09
0.98
Y
0.00
0.23
0.23
H
0.00
0.81
0.55
E
0.00
0.07
0.46
T
0.00
0.56
0.93
W
0.00
1.75
0.95
F
0.01
0.35
0.45
C
0.02
1.76
1.49
P
0.00
0.32
Variation
LPG / Diesel
LPG / Petrol
x 10
+1.1%
-32.3%
x7
+66.1%
-45.7%
x 72
+28.9%
x 93
-15.2%
x 106
-
Table 40: CO emission level (CADC Road cycle)
CO emission level (CADC Motorway cycle)
Vehicle
Diesel
Petrol
LPG
R
0.00
0.04
0.46
Y
0.00
0.36
0.40
H
0.00
1.26
1.34
E
0.01
0.04
0.89
T
0.00
0.52
2.40
W
0.00
5.59
1.34
F
0.00
0.35
0.87
C
0.00
2.62
4.16
P
0.01
0.92
Variation
LPG / Diesel
LPG / Petrol
x 11
+13.0%
+6.2%
x 89
x 22
+361.5%
-76.0%
x 243
+151.1%
x 4 157
+58.7%
x 91
-
Table 41: CO emission level (CADC Motorway cycle)
98
Vehicle
R
Y
H
E
T
W
F
C
P
CO emission level (CADC)
Diesel
Petrol
0.00
0.07
0.01
0.28
0.00
0.96
0.02
0.06
0.01
0.61
0.00
3.68
0.01
0.33
0.01
2.26
0.01
-
LPG
0.78
0.35
0.92
0.70
1.67
1.16
0.62
2.97
0.67
Variation
LPG / Diesel
LPG / Petrol
x 1 470
x 12
x 61
+24.9%
-4.1%
x 46
x 12
x 130
+173.8%
x 394
-68.3%
x 84
+91.0%
x 229
+31.3%
x 91
-
Table 42: CO emission level (CADC)
7.4.4
HC emissions
Vehicle
R
Y
H
E
T
W
F
C
P
HC emission level (NEDC)
Diesel
Petrol
0.033
0.105
0.028
0.123
0.006
0.092
0.020
0.120
0.040
0.050
0.010
0.020
0.038
0.026
0.062
0.062
0.017
-
LPG
0.045
0.122
0.096
0.090
0.040
0.030
0.021
0.074
0.030
Variation
LPG / Diesel
LPG / Petrol
+34.4%
-56.9%
+328.8%
-1.1%
x 15
+4.3%
+350.0%
-25.0%
-0.0%
-20.0%
+200.0%
+50.0%
-45.8%
-20.7%
+19.4%
+19.4%
+80.5%
-
Table 43: HC emission level (NEDC)
HC emission level (ECE cycle)
Vehicle
Diesel
Petrol
R
0.080
0.270
Y
0.064
0.325
H
0.014
0.244
E
0.040
0.318
T
0.100
0.124
W
0.020
0.060
F
0.090
0.065
C
0.147
0.150
P
0.032
-
LPG
0.121
0.328
0.257
0.220
0.110
0.070
0.054
0.189
0.078
Variation
LPG / Diesel
LPG / Petrol
+49.9%
-55.4%
+413.9%
+0.7%
x 18
+5.6%
+450.0%
-30.7%
+10.0%
-11.6%
+250.0%
+16.7%
-40.3%
-17.7%
+28.8%
+26.2%
+142.4%
-
Table 44: HC emission level (ECE cycle)
99
Vehicle
R
Y
H
E
T
W
F
C
P
HC emission level (EUDC)
Diesel
Petrol
0.006
0.007
0.008
0.004
0.002
0.004
0.010
0.006
0.010
0.001
0.000
0.000
0.007
0.003
0.012
0.010
0.008
-
LPG
0.001
0.001
0.002
0.010
0.000
0.000
0.001
0.006
0.003
Variation
LPG / Diesel
LPG / Petrol
-89.6%
-91.9%
-87.5%
-75.4%
-0.3%
-51.0%
-0.0%
+75.9%
-100.0%
-100.0%
-82.0%
-57.7%
-47.5%
-37.0%
-66.5%
-
Table 45: HC emission level (EUDC)
HC emission level (warm NEDC)
Vehicle
Diesel
Petrol
R
0.02
0.01
Y
0.01
0.02
H
0.00
0.00
E
0.01
0.18
T
0.02
0.00
W
0.01
0.00
F
0.00
0.00
C
0.02
0.03
P
0.01
-
LPG
0.01
0.05
0.02
0.07
0.01
0.00
0.00
0.04
0.00
Variation
LPG / Diesel
LPG / Petrol
-62.4%
-23.5%
+295.0%
+200.5%
x6
x7
+431.8%
-60.5%
-47.4%
+199.7%
-72.9%
+0.3%
+76.8%
+30.0%
+86.4%
+20.6%
-64.1%
-
Table 46: HC emission level (warm NEDC)
HC emission level (warm ECE cycle)
Vehicle
Diesel
Petrol
LPG
R
0.03
0.01
0.01
Y
0.02
0.04
0.13
H
0.01
0.00
0.05
E
0.02
0.48
0.18
T
0.04
0.01
0.03
W
0.02
0.01
0.01
F
0.00
0.00
0.01
C
0.04
0.07
0.10
P
0.02
0.01
Variation
LPG / Diesel
LPG / Petrol
-52.5%
+19.1%
x6
+272.6%
x8
x 15
x9
-62.5%
-25.0%
+200.0%
-50.0%
-0.0%
+171.8%
+164.4%
+143.9%
+38.9%
-71.8%
-
Table 47: HC emission level (warm ECE cycle)
100
HC emission level (warm EUDC)
Vehicle
Diesel
Petrol
R
0.01
0.01
Y
0.01
0.01
H
0.00
0.00
E
0.01
0.01
T
0.01
0.00
W
0.01
0.00
F
0.00
0.00
C
0.01
0.01
P
0.01
-
LPG
0.00
0.00
0.00
0.01
0.00
0.00
0.00
0.01
0.00
Variation
LPG / Diesel
LPG / Petrol
-85.2%
-79.2%
-88.8%
-83.7%
+72.7%
+6.9%
-0.0%
-0.0%
-100.0%
-100.0%
+9.1%
-32.1%
-36.4%
-41.7%
-51.3%
-
Table 48: HC emission level (warm EUDC)
HC emission level (CADC Urban cycle)
Vehicle
Diesel
Petrol
LPG
R
0.03
0.01
0.02
Y
0.02
0.03
0.12
H
0.01
0.02
0.04
E
0.03
0.04
0.07
T
0.03
0.01
0.01
W
0.03
0.01
0.00
F
0.02
0.00
0.00
C
0.04
0.08
0.03
P
0.02
0.00
Variation
LPG / Diesel
LPG / Petrol
-42.3%
+46.8%
+469.5%
+236.5%
+270.2%
+145.4%
+133.3%
+75.0%
-66.7%
-0.0%
-100.0%
-100.0%
-93.0%
-70.6%
-40.9%
-68.3%
-90.5%
-
Table 49: HC emission level (CADC Urban cycle)
HC emission level (CADC Road cycle)
Vehicle
Diesel
Petrol
LPG
R
0.01
0.01
0.00
Y
0.01
0.02
0.02
H
0.01
0.02
0.02
E
0.02
0.01
0.00
T
0.01
0.00
0.00
W
0.02
0.00
0.00
F
0.01
0.00
0.00
C
0.02
0.02
0.01
P
0.01
0.00
Variation
LPG / Diesel
LPG / Petrol
-41.4%
-37.4%
+98.6%
-1.7%
+158.7%
-11.4%
-100.0%
-100.0%
-100.0%
-100.0%
-73.3%
-37.7%
-62.1%
-54.5%
-71.3%
-
Table 50: HC emission level (CADC Road cycle)
101
HC emission level (CADC Motorway cycle)
Vehicle
Diesel
Petrol
LPG
R
0.00
0.01
0.01
Y
0.00
0.01
0.02
H
0.01
0.02
0.02
E
0.03
0.01
0.02
T
0.00
0.00
0.01
W
0.01
0.01
0.00
F
0.01
0.01
0.01
C
0.01
0.02
0.02
P
0.02
0.02
Variation
LPG / Diesel
LPG / Petrol
+129.7%
+27.0%
+289.7%
+17.4%
+290.0%
+32.8%
-33.3%
+100.0%
-100.0%
-100.0%
+74.8%
+57.9%
+86.0%
+3.3%
+21.7%
-
Table 51: HC emission level (CADC Motorway cycle)
Vehicle
R
Y
H
E
T
W
F
C
P
HC emission level (CADC)
Diesel
Petrol
0.01
0.01
0.01
0.02
0.01
0.02
0.03
0.01
0.01
0.00
0.02
0.01
0.01
0.01
0.02
0.03
0.01
-
LPG
0.01
0.03
0.02
0.02
0.01
0.00
0.01
0.02
0.01
Variation
LPG / Diesel
LPG / Petrol
-5.8%
+8.2%
+247.3%
+51.1%
+235.6%
+23.8%
-32.8%
+36.1%
-4.9%
x6
-100.0%
-100.0%
-23.8%
+20.3%
-12.2%
-36.8%
-18.7%
-
Table 52: HC emission level (CADC)
7.4.5
PM emissions
Vehicle
R
Y
H
E
T
W
F
C
P
PM emission level (NEDC)
Diesel
Petrol
0.022
< 0.001
0.038
0.002
0.039
0.001
0.027
0.012
0.030
0.039
0.024
0.042
-
LPG
< 0.001
< 0.001
0.001
0.001
-
Variation
LPG / Diesel
LPG / Petrol
-98.5%
-99.8%
-96.4%
-96.7%
-
Table 53: PM emission level (NEDC)
102
PM emission level (ECE cycle)
Vehicle
Diesel
Petrol
R
0.028
< 0.001
Y
0.041
0.005
H
0.047
0.001
E
0.038
T
0.019
W
0.035
F
0.046
C
0.030
P
0.049
-
LPG
< 0.001
< 0.001
0.003
0.001
-
Variation
LPG / Diesel
LPG / Petrol
-99.6%
-99.7%
-92.7%
+154.5%
-97.1%
-
Table 54: PM emission level (ECE cycle)
Vehicle
R
Y
H
E
T
W
F
C
P
PM emission level (EUDC)
Diesel
Petrol
0.019
< 0.001
0.035
0.001
0.034
0.000
0.020
0.007
0.027
0.025
0.020
0.037
-
LPG
< 0.001
< 0.001
< 0.001
0.001
-
Variation
LPG / Diesel
LPG / Petrol
-97.7%
-99.8%
-99.4%
-96.3%
-
Table 55: PM emission level (EUDC)
PM emission level (warm NEDC)
Vehicle
Diesel
Petrol
LPG
R
0.019
< 0.001
< 0.001
Y
0.029
0.001
< 0.001
H
0.032
0.003
0.001
E
0.026
T
0.008
W
0.024
0.002
F
0.033
C
0.017
P
0.034
-
Variation
LPG / Diesel
LPG / Petrol
-97.4%
-98.8%
-63.4%
-96.4%
-57.0%
-93.3%
-
Table 56: PM emission level (warm NEDC)
103
PM emission level (warm ECE cycle)
Vehicle
Diesel
Petrol
LPG
R
0.019
< 0.001
< 0.001
Y
0.031
0.002
< 0.001
H
0.031
0.005
0.002
E
0.034
T
0.011
W
0.025
0.001
F
0.026
C
0.016
P
0.036
-
Variation
LPG / Diesel
LPG / Petrol
-97.5%
-98.4%
-93.3%
-61.5%
-96.0%
-
Table 57: PM emission level (warm ECE cycle)
PM emission level (warm EUDC)
Vehicle
Diesel
Petrol
R
0.019
< 0.001
Y
0.028
0.001
H
0.032
0.001
E
0.022
T
0.007
W
0.024
F
0.036
C
0.017
P
0.033
-
LPG
0.001
0.000
0.001
0.002
-
Variation
LPG / Diesel
LPG / Petrol
-97.3%
-99.0%
-42.7%
-98.2%
-43.0%
-91.7%
-
Table 58: PM emission level (warm EUDC)
PM emission level (CADC Urban cycle)
Vehicle
Diesel
Petrol
LPG
R
0.085
< 0.001
0.002
Y
0.073
0.001
0.001
H
0.075
0.001
0.003
E
0.063
0.001
0.002
T
0.039
0.001
0.001
W
0.039
0.002
0.002
F
C
0.029
P
-
Variation
LPG / Diesel
LPG / Petrol
-97.2%
-99.0%
+16.2%
-95.3%
+464.8%
-96.8%
+100.0%
-97.4%
-0.0%
-94.9%
-0.0%
-
Table 59: PM emission level (CADC Urban cycle)
104
PM emission level (CADC Road cycle)
Vehicle
Diesel
Petrol
LPG
R
0.039
< 0.001
0.001
Y
0.030
0.001
< 0.001
H
0.039
0.001
0.001
E
0.037
0.002
0.002
T
0.030
0.001
0.002
W
0.030
0.001
0.001
F
C
0.020
P
-
Variation
LPG / Diesel
LPG / Petrol
-96.6%
-98.3%
-98.0%
+7.9%
-94.2%
+6.5%
-93.3%
+100.0%
-96.7%
-0.0%
-
Table 60: PM emission level (CADC Road cycle)
PM emission level (CADC Motorway cycle)
Vehicle
Diesel
Petrol
LPG
R
0.029
0.002
0.005
Y
0.032
0.002
0.003
H
0.055
0.006
0.003
E
0.123
0.013
0.011
T
0.023
0.030
0.013
W
0.046
0.006
0.011
F
C
0.025
P
-
Variation
LPG / Diesel
LPG / Petrol
-84.3%
+161.1%
-89.0%
+76.8%
-94.7%
-51.6%
-90.7%
-11.7%
-43.5%
-56.7%
-76.1%
+83.3%
-
Table 61: PM emission level (CADC Motorway cycle)
Vehicle
R
Y
H
E
T
W
F
C
P
PM emission level (CADC)
Diesel
Petrol
0.037
0.001
0.034
0.001
0.050
0.003
0.085
0.008
0.027
0.016
0.039
0.004
0.035
0.002
0.023
0.045
-
LPG
0.003
0.002
0.002
0.007
0.008
0.006
0.002
0.007
Variation
LPG / Diesel
LPG / Petrol
-91.6%
+178.0%
-93.9%
+58.0%
-95.7%
-38.4%
-91.7%
-8.5%
-71.4%
-52.7%
-83.7%
+71.1%
-95.7%
-18.6%
-84.3%
-
Table 62: PM emission level (CADC)
105
7.4.6
Oxygenated compounds
Formaldehyde emission level (NEDC)
Vehicle
Diesel
Petrol
LPG
R
2.986
0.737
0.494
Y
6.716
1.031
0.312
H
6.770
0.638
0.445
E
T
W
F
C
P
-
Variation
LPG / Diesel
LPG / Petrol
-83.4%
-32.9%
-95.3%
-69.7%
-93.4%
-30.3%
-
Table 63: Formaldehyde emission level (NEDC)
Acetaldehyde emission level (NEDC)
Vehicle
Diesel
Petrol
LPG
R
1.563
0.236
0.234
Y
2.483
0.390
0.202
H
2.503
0.294
0.105
E
T
W
F
C
P
-
Variation
LPG / Diesel
LPG / Petrol
-85.1%
-0.9%
-91.9%
-48.1%
-95.8%
-64.4%
-
Table 64: Acetaldehyde emission level (NEDC)
Formaldehyde emission level (CADC)
Vehicle
Diesel
Petrol
LPG
R
0.822
0.070
0.043
Y
0.831
0.125
0.076
H
0.840
0.075
0.072
E
0.985
0.231
0.038
T
W
1.796
0.052
0.028
F
0.032
0.015
0.013
C
1.362
0.744
0.117
P
0.216
0.003
Variation
LPG / Diesel
LPG / Petrol
-94.8%
-38.9%
-90.8%
-39.0%
-91.4%
-3.4%
-96.1%
-83.4%
-98.4%
-46.6%
-60.7%
-13.3%
-91.4%
-84.3%
-98.4%
-
Table 65: Formaldehyde emission level (CADC)
106
Acetaldehyde emission level (CADC)
Vehicle
Diesel
Petrol
LPG
R
0.237
0.242
0.154
Y
0.236
0.155
0.157
H
0.238
0.395
0.106
E
0.351
0.153
0.152
T
0.047
W
0.782
0.032
0.043
F
0.071
0.013
0.022
C
0.338
0.091
0.082
P
0.003
0.001
Variation
LPG / Diesel
-35.1%
-33.4%
-55.7%
-56.7%
-94.4%
-69.2%
-75.7%
-54.1%
LPG / Petrol
-36.5%
+1.6%
-73.3%
-0.6%
+34.4%
+73.3%
-10.2%
-
Table 66: Acetaldehyde emission level (CADC)
7.4.7 PAH
Note: the value marked in red correspond to values measured only on the solid phase (no gaseous
PAH).
"2A" PAH emission level (CADC)
Vehicle
Diesel
Petrol
LPG
R
0.166
n.s.
n.s.
Y
0.122
n.s.
n.s.
H
0.126
n.s.
n.s.
E
0.117
1.377
0.144
T
< 0.001
0.020
n.s.
W
0.113
0.002
n.s.
F
0.750
0.707
0.560
C
< 0.001
< 0.001
< 0.001
P
0.111
0.386
Variation
LPG / Diesel
LPG / Petrol
+23.2%
-89.6%
-100.0%
-25.4%
-20.8%
+249.1%
-
Table 67: "2A" PAH emission level (CADC)
107
"2B" PAH emission level (CADC)
Vehicle
Diesel
Petrol
LPG
R
0.223
n.s.
n.s.
Y
0.108
n.s.
n.s.
H
0.138
n.s.
n.s.
E
0.486
2.336
0.096
T
0.007
0.050
< 0.001
W
0.319
0.000
< 0.001
F
0.192
0.053
0.269
C
< 0.001
< 0.001
< 0.001
P
0.369
0.211
Variation
LPG / Diesel
LPG / Petrol
-80.2%
-95.9%
+40.4%
+410.5%
-42.9%
-
Table 68: "2B" PAH emission level (CADC)
Vehicle
R
Y
H
E
T
W
F
C
P
PAH emission level (CADC)
Diesel
Petrol
16.400
2.300
19.600
2.050
20.300
2.200
3.071
180.787
2.386
8.800
15.291
34.109
29.470
18.404
21.484
3.650
20.459
-
LPG
1.300
1.200
1.200
8.487
11.886
47.906
0.418
25.423
Variation
LPG / Diesel
LPG / Petrol
-92.1%
-43.5%
-93.9%
-41.5%
-94.1%
-45.5%
+176.3%
-95.3%
-22.3%
-65.2%
+62.6%
+160.3%
-98.1%
-88.6%
+24.3%
-
Table 69: PAH emission level (CADC)
7.4.8
BTX
benzene emission level (NEDC)
Vehicle
Diesel
Petrol
R
0.048
2.258
Y
0.665
2.398
H
0.304
2.062
E
T
W
F
C
P
-
LPG
0.438
0.829
0.448
-
Variation
LPG / Diesel
LPG / Petrol
x9
-80.6%
+24.6%
-65.4%
+47.5%
-78.3%
-
Table 70: benzene emission level (NEDC)
108
toluene emission level (NEDC)
Vehicle
Diesel
Petrol
LPG
R
0.011
8.683
1.584
Y
0.000
10.349
2.562
H
0.000
8.569
1.645
E
T
W
F
C
P
-
Variation
LPG / Diesel
LPG / Petrol
x 147
-81.8%
-75.2%
-80.8%
-
Table 71: toluene emission level (NEDC)
p,m-xylene emission level (NEDC)
Vehicle
Diesel
Petrol
LPG
R
0.003
1.743
0.000
Y
0.056
2.066
0.561
H
0.000
1.742
0.275
E
T
W
F
C
P
-
Variation
LPG / Diesel
LPG / Petrol
-100.0%
-100.0%
x 10
-72.8%
-84.2%
-
Table 72: p,m-xylene emission level (NEDC)
o-xylene emission level (NEDC)
Vehicle
Diesel
Petrol
R
0.001
0.782
Y
0.014
0.843
H
0.004
0.742
E
T
W
F
C
P
-
LPG
0.000
0.249
0.108
-
Variation
LPG / Diesel
LPG / Petrol
-100.0%
-100.0%
x 18
-70.4%
x 27
-85.5%
-
Table 73: o-xylene emission level (NEDC)
109
benzene emission level (CADC)
Vehicle
Diesel
Petrol
R
0.126
0.167
Y
0.135
0.000
H
0.106
1.302
E
0.168
0.948
T
0.221
0.420
W
0.307
0.737
F
0.039
0.097
C
0.212
1.200
P
0.038
-
LPG
0.000
0.331
0.157
0.186
0.054
0.192
0.001
0.002
0.054
Variation
LPG / Diesel
LPG / Petrol
-100.0%
-100.0%
+144.4%
+48.6%
-87.9%
+10.8%
-80.4%
-75.7%
-87.2%
-37.3%
-73.9%
-97.5%
-99.0%
-98.9%
-99.8%
+42.0%
-
Table 74: benzene emission level (CADC)
Vehicle
R
Y
H
E
T
W
F
C
P
toluene emission level (CADC)
Diesel
Petrol
0.274
0.363
0.193
0.358
0.379
1.432
n.s.
2.682
n.s.
0.104
n.s.
0.132
0.057
0.290
0.146
0.939
0.009
-
LPG
0.083
0.442
0.153
0.127
n.s.
0.036
0.117
n.s.
0.022
Variation
LPG / Diesel
LPG / Petrol
-69.6%
-77.1%
+129.4%
+23.6%
-59.7%
-89.3%
-95.3%
-73.1%
+106.8%
-59.5%
-100.0%
-100.0%
+129.5%
-
Table 75: toluene emission level (CADC)
p,m-xylene emission level (CADC)
Vehicle
Diesel
Petrol
LPG
R
0.021
0.095
0.026
Y
0.000
0.269
0.068
H
0.044
0.224
0.028
E
0.000
0.761
0.119
T
0.000
0.013
0.000
W
0.005
0.046
0.013
F
0.022
0.044
0.020
C
0.049
0.268
0.000
P
0.000
0.005
Variation
LPG / Diesel
LPG / Petrol
+21.5%
-72.8%
-74.8%
-36.9%
-87.7%
-84.3%
-100.0%
+165.8%
-71.8%
-9.1%
-55.6%
-99.2%
-99.8%
-
Table 76: p,m-xylene emission level (CADC)
110
o-xylene emission level (CADC)
Vehicle
Diesel
Petrol
R
0.026
0.028
Y
0.029
0.126
H
0.021
0.106
E
n.s.
0.282
T
n.s.
n.s.
W
n.s.
n.s.
F
0.024
0.021
C
0.019
0.113
P
0.031
-
LPG
0.012
0.039
0.010
0.053
n.s.
n.s.
0.008
0.002
0.004
Variation
LPG / Diesel
LPG / Petrol
-53.2%
-57.2%
+36.6%
-69.0%
-51.4%
-90.3%
-81.3%
-65.9%
-60.7%
-91.7%
-98.6%
-88.2%
-
Table 77: o-xylene emission level (CADC)
7.4.9
NO2
Vehicle
R
Y
H
E
T
W
F
C
P
NO2 emission level (NEDC)
Diesel
Petrol
56
31
50
28
65
20
-
LPG
27
46
20
-
Variation
LPG / Diesel
LPG / Petrol
-51.6%
-12.8%
-8.0%
+64.9%
-69.6%
-0.3%
-
Table 78: NO2 emission level (%age of total NOx emissions) - (NEDC)
NO2 emission level (CADC)
Vehicle
Diesel
Petrol
R
75
31
Y
52
31
H
63
30
E
45
3
T
61
7
W
33
3
F
C
P
-
LPG
31
31
33
5
8
0
-
Variation
LPG / Diesel
LPG / Petrol
-59.1%
-2.4%
-41.1%
+0.3%
-48.5%
+8.2%
-89.3%
+58.9%
-87.4%
+11.0%
-100.0%
-100.0%
-
Table 79: NO2 emission level (%age of total NOx emissions) - (CADC)
111
7.4.10 Ozone formation
POCP emission level (g eq ethene/km - CADC)
Vehicle
Diesel
Petrol
LPG
R
0.126
0.269
2.218
Y
0.140
1.019
1.350
H
0.125
2.961
2.834
E
0.127
0.689
1.955
T
0.098
1.669
4.532
W
0.190
9.976
3.165
F
0.073
0.945
1.760
C
P
0.092
2.022
Variation
LPG / Diesel
LPG / Petrol
x 18
x8
x 10
+32.5%
x 23
-4.3%
x 15
+183.8%
x 46
+171.5%
x 17
-68.3%
x 24
+86.1%
x 22
-
Table 80: POCP emission level (g eq ethene/km - CADC)
TOFP emission level (gNMVOC eq/km - CADC)
Vehicle
Diesel
Petrol
LPG
R
0.862
0.322
0.179
Y
1.069
0.168
0.142
H
1.134
0.165
0.169
E
0.958
0.081
0.131
T
1.095
0.089
0.200
W
0.803
0.418
0.128
F
0.862
0.094
0.105
C
P
1.524
0.089
Variation
LPG / Diesel
LPG / Petrol
-79.3%
-44.5%
-86.7%
-15.2%
-85.1%
+2.4%
-86.3%
+61.4%
-81.7%
+125.9%
-84.0%
-69.3%
-87.8%
+11.9%
-94.1%
-
Table 81: TOFP emission level (gNMVOC eq/km - CADC)
112
7.4.11 Acidification potential
Acidification potential emission level (mmolH+/km CADC)
Vehicle
Diesel
Petrol
LPG
R
Y
H
E
16.634
1.771
5.871
T
19.325
1.898
6.115
W
14.031
3.332
1.129
F
C
P
-
Variation
LPG / Diesel
-64.7%
-68.4%
-92.0%
-
LPG / Petrol
+231.4%
+222.2%
-66.1%
-
Table 82: Acidification potential emission level (mmolH+/km - CADC)
7.4.12 Global warming potential
GWP (2001) emission level (gCO2/km equ - CADC)
Vehicle
Diesel
Petrol
LPG
R
153.904
169.126
159.013
Y
158.411
167.460
150.892
H
146.041
160.200
138.556
E
172.607
184.533
164.592
T
190.093
222.533
202.229
W
140.778
169.417
159.544
F
C
P
-
Variation
LPG / Diesel
LPG / Petrol
+3.3%
-6.0%
-4.7%
-9.9%
-5.1%
-13.5%
-4.6%
-10.8%
+6.4%
-9.1%
+13.3%
-5.8%
-
Table 83: GWP (2001) emission level (gCO2/km equ - CADC)
113

EETP: "European Emission Test Programme" Final report

Transcription

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