EURO 5

Transcription

EURO 5

Moderni sistemi di abbattimento
degli inquinanti nei Diesel
Dr. Ing. Francesco Paolo Ausiello
Magneti Marelli Innovation
Giovedì 27 Novembre 2008
Corso di Motori Endotermici Alternativi B, A.A. 2008-09
Prof. Enrico Mattarelli
NOVEMBER 2008
Contenuti
Le emissioni di un motore diesel
Le normative di riferimento
f Evoluzione
f Stato
f Previsioni
Evoluzione dei sistemi di controllo Diesel
f EURO 4
f EURO 5
Trend di evoluzione
f EURO 6
NOVEMBER 2008
2
Le emissioni di un motore Diesel
Particolato (PM/Soot/Smoke), ed NOx sono le più significative
La loro concentrazione locale, all’interno del cilindro e durante la
combustione, dipende dalle condizioni locali di TEMPERATURA e
RAPPORTO DÌ EQUIVALENZA (diagramma collinare)
NOVEMBER 2008
3
Le emissioni di un motore diesel ( Engine out) )
0,15
PM *
0,1
0,05
0,02
0
0
1
2
3
4
5
6
7
8
9 10 11
Nella combustione convenzionale, ad alte concentrazioni di NOx corrispondono bassi valori di fumosità
e viceversa
NOVEMBER 2008
4
NOx
NOx PM TRADE OFF
Con EGR si possono ridurre sensibilmente gli NOx senza penalizzare troppo PM
0,15
con EGR
PM *
[g/kWh]
Senza EGR
0,1
NOx / PM trade off
0,05
0,02
0
0
1
2
3
4
5
6
7
8
9
10
11
NOx [g/kWh]
NOVEMBER 2008
5
Le normative di riferimento
f Evoluzione
f Stato
f Previsioni
NOVEMBER 2008
6
LA STRADA PERCORSA E’ STATA MOLTO VELOCE PER IL DIESEL
NOVEMBER 2008
7
ECE NEUDC TESTING CYCLE
Il nuovo ciclo guida europeo (New European Driving Cycle,
NEDC) si compone di quattro parti uguali che simulano la guida
urbana, e di una extra-urbana
EXTRAURBAN
100
URBAN
Time (s)
L’auto viene posta su di un
Banco a Rulli che simula il
carico alle ruote
NOVEMBER 2008
8
1150
1100
1050
1000
950
900
850
800
750
700
650
600
550
500
450
400
300
250
200
150
100
50
0
350
50
0
Velocità (km/h)
150
Advanced Measurement Technology
State of the art engine development requires very advanced measurement
technologies, especially for exhaust gas analysis.
Beside combustion emission benches, smoke meter, smart sampler,
opacimeter and constant volume sampling as standard devices, also dual
differential mobility particle spectrometer at steady state engine operation
and transient differential mobility particle spectrometer at transient engine
operation are used to analyze particle number size distributions.
The soot loading of a Diesel particulate
filter can easily be measured by weighting,
whereas an analysis of the soot loading
distribution leads to destruction of the
filter for various procedures.
As example
AVL has developed a method based on
Computer Tomographic investigations
(CT), which leads to reproducible results
without destruction of the DPF.
TECNOLOGIE SPERIMENTALI MOLTO COMPLESSE !!!!
NOVEMBER 2008
9
LIMITI EURO 5
NOVEMBER 2008
10
LIMITI EURO 6
NOVEMBER 2008
11
LE NORME EUROPEE
Il passaggio progressivo dalle norme Euro 3 alle norme Euro 4 e
quelli in corso verso le norme Euro 5 e 6 hanno ridotto
sensibilmente i valori limite a nuovo
Con il passaggio ad Euro 5 inoltre si introduce il concetto di
conformità nel tempo
NOVEMBER 2008
12
LE NORME USA
NOVEMBER 2008
13
Paragone EUROPA USA
Dati in g/km
CO
NOx
PM
HC
EURO 5
0,5
0,180
0,005
0,068
EURO 6
0,5
0,080
0,005
0,068
LEV/ULEV 50 k ml
2.1 / 1.1
0,031
0.00
0,0094 / 0,005
LEV/ULEV 120 k ml
2.6 / 1.3
0,044
0,0063
0,0110 / 0,007
Questa diminuzione rende di fatto necessaria la adozione di misure anti NOx
Questa differenza constringe alla adozioni di sistemi di abbattimento differenti dell’ NOx in USA e EU
Il controllo degli idrocarburi rende necessario l’uso del catalizzatore ossidante subito a valle della turbina
NOVEMBER 2008
14
Diesel Euro 5 /6 NOx & PM emission standards
0.025
Euro 4
2005
Passenger cars – European Legislation
NOx 250 mg/km
Particulate (g / km)
0.020
Euro 4
0.015
0.010
0.005
NOx 80 mg/km
NOx 180 mg/km
Euro6
0.05
Euro 5
0.10
0.15
0.20
0.25
NOx (g / km)
NOVEMBER 2008
15
EU Exhaust Emission Legislation
Incentives Timing
Tax incentives:
• The incentive leverage is currently used to accelerate the
introduction of more stringent emission levels
• This practice seems now no more feasible for pollution reasons due
to the high cost on the community
• Incentives are oe devoted to energy / CO2 saving target
Euro4 tax incentive period
Tax Incentives
Regulation
CY 99
envisaged Euro 5
incentive period
EURO 3
00
NOVEMBER 2008
01
02
03
EURO 4
04
05
06
07
08
EURO 6
EURO 5
09
10
11
12
13 14
16
CO2 FLEET LIMITS EVOLUTION (EU)
g/km
EU old prop.
EU CO2
reduction
Vs,1995
EU new prop.
200
10%
165
2004
150
20%
140
2008
30%
130
40%
120
100
2012
2015
50%
95
2020
70
2025
50
1995
2000
2005
2010
2015
2020
2025
Year
Proposte di limitazione di CO2 in Europa (il costruttore che ha auto che emettono
mediamente più CO2 del limite paga una tassa in proporzione)
NOVEMBER 2008
17
EMISSIONI DI CO2 DEI COSTRUTTORI AUTO
320
383
300
433
286
280
240
220
146
FGA
FIAT
149
154
158
GM
143
153
HONDA
142
PSA
160
TOYOTA
Media = 160g/km
164
166 167
168
169
184
186
DC
180
NISSAN
180
BMW
200
SUZUKI
CO2 [g/km]
260
Ferrari*
Maserati*
PORSCHE
OTHER
VW
HYUNDAI
FORD
120
RENAULT
140
Fonte: AAA data
NOVEMBER 2008
18
PENALTY TO CO2 LIMIT EMISSIONS EU SCENARIO
5000
4500
2015
4000
Penalty per car [€]
3500
3000
2500
2000
1500
2012
1000
500
Daimler
BMW
Mazda
Suzuki
Mitsubishi
Nissan
Hyundai
Volkswagen
Ford
GM
Honda
Toyota
Fiat
Renault
PSA
0
Car Manufacturers
NOVEMBER 2008
19
Evoluzione dei sistemi di controllo Diesel
f EURO III
CR 0 generazione
UNIJET
f EURO IV
CR 1 a generazione
MULTIJET
f EURO V
CR 2 a generazione
MULTIJET 2
f EURO VI
Prossime evoluzioni sistema di iniezione diesel
NOVEMBER 2008
20
Dalla pompa meccanica al common rail
Nel 1985 comincia la operazione di meccatronica per trasformare la
pompa di iniezione diesel in un sistema di iniezione ad alta pressione
f
f
f
f
f
f
Brevetti iniziali
Definizione sistema Common rail
Analisi funzionale Definizioni obiettivi
Fattibilità
Sviluppo industriale
Start of production
NOVEMBER 2008
1973
1986
1990
1991
1994
1997
( Sofredi) US Patent 4219154
( Marelli)
( Marelli ,CRF )
( Elasis , CRF )
( Elasis ,Bosch)
(Bosch
21
Common Rail System EURO 3 ( UNIJET)
CP1
CP1 High
High Pressure
Pressure
Pump
Pump
Fuel
Fuel Metering
Metering
Valve
Valve (MPROP)
(MPROP)
Max
Max
pressure
pressure
140
140 MPa
MPa
RailPressure
RailPressure
Sensor
Sensor
Rail
Electrical
Electrical
Feeding
Feeding Pump
Pump
Tank
Jet-pump
High Pressure Lines
Low Pressure Lines
NOVEMBER 2008
MJD-6X
MJD-6X
ECU
ECU
CRI2.2
CRI2.2 Injectors
Injectors
22
Euro 3 Engine Management System
1. Fuel tank
2. Electric Fuel-feeding Pump
3. Fuel Filter Assembly
4. High Pressure Pump
5. Fuel Metering Valve
6. Rail
7. Rail Pressure Sensor
8. Injectors
9. Air Filter
10. Air Flow Meter +Air Temperature Sensor
11. Compressor
12. Intercooler
13. Electronic Throttle Body (DC-motor)
14. Electronic EGR Valve (DC-motor)
15. EGR Cooler
16. EGR Cooler by-pass valve
17. Intake Manifold Pressure + Temperature Sensor
18. Engine Speed (Crankshaft) Sensor
19. Camshaft Position Sensor
20. Oil Minimum Pressure Switch
21. Coolant Temperature Sensor
22. Low voltage Glow Plugs
23. Low voltage Glow Plug Control Unit
24. Waste gate Geometry Turbine
25. VGT actuator with position sensor (or FGT actuator)
26. VGT/FGT Vacuum Modulator
27. Lambda sensor (together with DPF)
28. Close Coupled Diesel Particulate Filter
29. Inlet DPF Temperature Sensor
30. DPF Differential Pressure Sensor
31. Pedal Assembly
32. Engine Control Unit
NOVEMBER 2008
17
3
31
2
7
6
to the vehicle
32
1
18
8
4
15
5
20
21
19
10
24
11
9
12
23
System from EURO 3 to EURO 4 MULTIJET
From Pilot Injection...
PILOT
Common Rail
1st generation
MAIN
FUELLING
PILOT
MAIN
POST
COMBUSTION
RATE
-60°
PRE
MAIN
TDC
… to Multiple Injections
AFTER
MULTIJET
Common Rail
+60°
PILOT PRE MAIN AFTER
POST
FUELLING
Noise control
DPF
in cold operation
regeneration
and low rpm
Injection Duration Control
Combustion Rate Shaping
Soot oxidation
COMBUSTION
RATE
-60°
TDC
+60°
Flexible control of more injections per cycle, with almost no restrictions in
number and distance
–
–
Up to 5 injections per cycle
Minimum dwell time between to consecutive injections: 100µs
NOVEMBER 2008
24
Injection rate, rate shaping, optimisation opportunities.
NO pre injection
1 pre injection
2 pre injection
NOVEMBER 2008
25
1. Fuel tank
6. Rail
8. Injectors
9. Air Filter
11. Compressor
12. Intercooler
14 VALVOLA EGRlectronic EGR Valve (DC-motor)
15. EGR Cooler
24. Variable Geometry Turbine (or FGT)
31. Pedal Assembly
17
3
31
2
7
6
to the vehicle
14
32
1
18
8
4
15
5
20
21
19
28
29
26
10
24
11
30
27
9
12
Filtro anti-particolato (DPF)
NOVEMBER 2008
26
1. Fuel tank
6. Rail
8. Injectors
9. Air Filter
11. Compressor
12. Intercooler
14. Electronic EGR Valve (DC-motor)
15. EGR Cooler
24. Variable Geometry Turbine (or FGT)
31. Pedal Assembly
17
13
3
31
2
7
6
to the vehicle
32
14
1
18
8
4
15
5
22
20
19
28
25
29
26
21
16
23
10
24
11
30
27
9
12
Red: new or heavily modified components compared to Euro 4 system
NOVEMBER 2008
27
MJ2 Diesel Components Overview
Variable Delivery High
Pressure Pump
Fuel Rail
Electrical Throttle Body w/
or w/o embedded control
Volume
Control
Valve
Swirl
Smart
Actuator
Fast
Solenoid
Injectors
Engine
Control
Unit
NOVEMBER 2008
Integrated Intake
Manifold w/ or w/o
swirl
28
Euro 4/5 Gas Components
Rispetto ad Euro3 sono stati generalmente aggiunti:
1.Valvola EGR e scambiatore per raffreddare i gas di scarico (EGR-Cooler)
2.Valvola a farfalla (throttle) per controllare meglio il flusso di aria (utile per
elevati valori di EGR)
3.Filtro anti-particolato (DPF)
4.Turbina a geometria variabile anziché Waste-Gate per aumentare la portata di
aria a carico parziale (meno fumo)
5.Dispositivi di controllo dello swirl (Swirl control)
6.Attuatori e sensori
NOVEMBER 2008
29
Euro 4 Air Intake Manifold
C’è un valore ottimale della posizione del flap
NOVEMBER 2008
30
Euro 4 – Diesel Air Intake Manifold
NOVEMBER 2008
31
Euro 4 – Swirl flap air flow optimization
NOVEMBER 2008
32
Euro 4 – Swirl flap air flow optimization
NOVEMBER 2008
33
NEW FUCTIONS
Euro 4 functions are preserving diesel emission deterioration in time
Euro V function are including a first step toward fuel neutral emission
Euro VI will almost equalize diesel and gasoline emissions
NOVEMBER 2008
34
DA EURO 4 a EURO 5
NOVEMBER 2008
35
Strategies to meet Euro 5
Mainstream: Add DPF, reduce NOx engine out emissions
0.025
Euro 4
2005
Passenger cars – European Legislation
Current
Technologies
w/o DPF
0.020
Step 1
Combustion improvement
(Conventional Combustion)
0.015
•Add DPF
•Revise calibrations
0.010
0.005
Euro 5
Euro6
0.05
0.10
0.15
0.20
0.25
NOx (g / km)
NOVEMBER 2008
36
Strategy: to work towards Euro 5 Scenario”
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f
ENHANCED CONVENTIONAL COMBUSTION
ENHANCED GLOW PLUG SYSTEM
IMPROVED EGR CYLINDER TO CYLINDER DISTRIBUTION
HIGH EFFICIENCY EGR COOLER with BY – PASS
EMISSIONS DISPERSION CONTROL
DPF
f CLOSED COUPLED
SI PREVEDE UNA OTTIMIZZAZIONE DEI SISTEMI GIA’ PRESENTI
NOVEMBER 2008
37
Euro 5 Engine Management System - New Functions
Enhanced air system management
f
f
f
f
f
EGR cooler by–pass
EGR DC-motor valve
Electrical Throttle Valve
Variable Geometry Turbine with actuator position sensor
Variable swirl management( on large displacement engines)
NOX management strategies
f
f
f
Long-route (or low-pressure) EGR management
PHCCI
Selective catalitic reaction ( UREA Addition)
f
f
f
f
Enhanced Glow Plug management (low voltage)
Closed-loop smoke control in transient
Multiple injection
Injector Rate Shaping (IRS)
DPF strategy improvement
f
f
Low O2 regeneration for advanced DPF (closed coupled, cordierite)
Multi post injection
Driveability
f
Energy Shaking Driveline Damping (ESDD)
NOVEMBER 2008
38
MULTIJET 2 Common Rail System for Euro 5
Features
New fast solenoid injector with pressure balanced shutter servovalve
3-plunger high pressure pump with Volume Control Valve
1600 bar max pressure
Generation 8 ECU
Advantages
Fully flexible management of
multiple injections
f up to 8 injections per cycle
f Injection Rate Shaping (IRS)
Volume
Volume
Control
Control
Valve
Valve (VCV)
(VCV)
160
160 MPa
MPa
CP1H
CP1H High
High
Pressure
Pressure Pump
Pump
Fuel
Fuel
Pressure
Pressure
Sensor
Sensor
Fuel
FuelFilter
Filterwith:
with:
••
••
••
Temperature
TemperatureSensor
Sensor
Water
WaterSeparator
Separator
Water-in-Fuel
Sensor
Water-in-Fuel Sensor
Improved fuel metering accuracy
Optimal pressure control
Tank
Gen.
Gen. 88
ECU
ECU
Electrical
Electrical
Feeding
Feeding
Pump
Pump
NOVEMBER 2008
MJ2
MJ2 Injectors
Injectors
39
Enhanced Multiple Injection Capability
ETpil
ETpre
DTpil
DTpre
PILOT
SOIpil
ETmain
PRE
SOIpre
ETaft
SOImain
ETpost2
ETpost3
ETpost3
POST1
POST2
POST3
POST4
DTpost
DTaft
MAIN
ETpost1
AFTER
SOIaft
SOIpost1 DTpost2
DTpost3
DTpost3
BMEP ( bar )20
Rail Pressure
15
1600 bar
10
1200 bar
5
800 bar
400 bar
DPF REGENERATION
NOVEMBER 2008
1000
2000
3000
Engine Speed ( rpm )
4000
5000
40
MULTIJET 2 Injector
Flexible dwell time without not permitted area
Allowable dwell time between sequential injections
MJ2 Injector
Dwell Time Range Capability
1600
1600
1400
1400
Injection pressure [bar]
Injection pressure [bar]
Current Injector
Dwell Time Range Capability
1200
1000
800
600
400
1200
1000
Only in
cold
conditions
NO RESTRICTION ON
DWELL TIME CALIBRATION
800
600
400
200
0
200
400
600
800
1000
1200
1400
1600
1800
Dwell time [µs]
Not permitted area
MULTIJET
MULTIJET
2000
200
0
200
400
600
800
1000
1200
Dwell time [µs]
1400
1600
MULTIJET
MULTIJET 22
Dwell time: intervallo tra due iniezioni consecutive nello stesso ciclo (vincolato sul MULTIJET)
NOVEMBER 2008
41
1800
2000
DWELL TIME OPTIMIZATION
[° CA]
NOVEMBER 2008
42
MULTIJET 2 Injector
Injector Rate Shaping
MULTIJET
MULTIJET
PILOT
PRE MAIN
Injection Rate
AFTER
POST
Min = 250 µs
Injection Rate
MULTIJET
MULTIJET 22
PILOT
PRE+MAIN AFTER
Pre
Pre ++ Main
Main at
at zero
zero
hydraulic
dwell
hydraulic dwell time
time
MULTIPOST
Close
Close After
After Injection
Injection
<100 µs
Zero hydraulic dwell time
NOVEMBER 2008
43
Bypass Valve
High Efficiency EGR
Cooler with Bypass
Turbine
(VGT)
Enhanced
Glow plugEGR
Valve
Lambda
Sensor
Knock
Sensor
(TBD)
Throttle Air Flow
Valve Meter
(DC Motor)
Calibration
Particulate Emissions
Enhanced Conventional Combustion
Comb 1
• Reduced Comp. Ratio
• Increased EGR Rate
• Combustion Opt.
ECU
Exhaust
System
0.12
Enhanced Conventional
0.20
0.25
NOx Emissions (g/km)
Reduced
Reduced Compression
Compression Ratio
Ratio (16.5:1)
(16.5:1)
zz
Improved
Improved EGR
EGR cyl-to-cyl
cyl-to-cyl distribution
distribution
zz
Improved
Improved Solenoid
Solenoid Injector
Injector (CRI
(CRI 2.2
2.2 sol.
sol. 2)
2)
zz
High
High Efficiency
Efficiency EGR
EGR Cooler
Cooler with
with by-pass
by-pass
zz
Enhanced
Enhanced glow
glow plug
plug system
system
NOVEMBER 2008
Candelette
44
Enhanced Glow Plug System
System
CURRENT
ENHANCED
Type
Metal
Ceramic
Heat-up Time
850 °C < 5s
1000 °C < 5s
Glowing Temp.
~ 950 °C
~ 1150 °C
Voltage
11 V
7V
Glow Control Unit
Relay
Transistor
Lifetime
15000 cycles
60000 cycles
Features
9 Fast heat-up time
9 Operating temperature up to 1150 °C
9 No drop in temperature due to voltage drop during
engine start (over
9 Temperature control possible when after engine
start increased air flow cools down the plug
9 Post and intermediate glow capability (e.g. post
glow operation)
NOVEMBER 2008
Results
Results @
@ -20
-20 °C
°C
¾
¾ Very
Very good
good starting
starting time
time even
even with
with prepreglow
reduced
from
10s
to
2
s
glow reduced from 10s to 2 s
¾
¾ Excellent
Excellent idle
idle stabilization
stabilization
¾
¾ No
No misfire
misfire with
with very
very low
low HC
HC emission
emission
(50%
(50% HC
HC reduction
reduction vs
vs current
current system)
system)
45
Improved EGR cylinder-to-cylinder distribution
Computations & tests show EGR distribution problem with existing
manifold
¾ Cylinder 4 is the worst case
Improvement by insert a plate into existing manifold (EGR diffuser)
EGR
diffuser
Air flow
from
charge air
cooler
Exhaust
gas from
EGR line
Effect of EGR diffuser
1500x2, 2.00 lambda, 46% EGR
50%
48%
Baseline
with diffuser
46%
Current
Improved
EGR
44%
42%
40%
secondary
primary
secondary
primary
secondary
primary
secondary
Cylinder 4
primary
38%
cyl. #1 cyl. #1 cyl. #2 cyl. #2 cyl. #3 cyl. #3 cyl. #4 cyl. #4
NOVEMBER 2008
46
High Efficiency EGR Cooler with by-pass
Cooler tubes closed or
opened by a flap valve
(by-pass)
Cooled Exhaust Gas
Hot Exhaust Gas
Cooling tubes
EGR COOLER EFFICIENCY
1
“Hot EGR” (by-pass)
OR
“Cooled EGR”
Coolant
Pipes
0.9
Hot Exhaust Gas
from EGR Valve
EFFICIENCY
0.8
EGR By-pass
Actuator
0.7
0.6
0.5
0.4
0
10
20
30
40
50
60
70
EGR FLOW [kg/h]
NOVEMBER 2008
47
80
La valvola EGR è una valvola
a fungo, con un attuatore
pneumatico o un solenoide
EGR raffreddato dall’
acqua del motore
La farfalla (Throttle) è a monte
del miscelatore aria-gas di scarico
per generare maggiore differenza
di pressione Æpiù EGR
NOVEMBER 2008
48
COOLED EGR IMPACT ON PM/NOX TRADE OFF
NOVEMBER 2008
49
SHORT TERM STRATEGY
Emission Dispersion Control
Dispersion trend is
consistent in previous Euro
3 and Euro 4 experience
Un controllo in retroazione con sonda Lambda riduce
significativamente le differenze tra un motore e l’altro
in termini di emissioni. LA DISPERSIONE E’ UN COSTO
PER IL COSTRUTTORE
Effect of Lambda-based Dispersion Control (CRF)
0,07
Considering more stringent
Euro 5 limits lambda sensor
will be applied with DPF
Without Lambda control
With Lambda Control
0,06
0,05
PM (g/km)
Lambda sensor was applied
on Euro 4 applications w/o
DPF in order to reduce
emission dispersion at zero
km and emission drift during
lifetime
Euro 3
0,04
0,03
Euro 4
0,02
0,01
Euro 5
0
0
NOVEMBER 2008
0,1
0,2
0,3
NOx (g/km)
0,4
0,5
0,6
50
0,7
Sistemi Abbattimento PM : La trappola del particolato
f Con additivi ( Bare Trap) (FAP)
f Catalizzata CST ( Catalyzed Soot Trap)

I componenti
Le strategie
La durata nel tempo ( Rigenerazione)
Punti critici

I componenti
Le strategie
Punti critici
Due tipi di trappole/filtri anti-particolato: trappola semplice(Æaddittivi) e trappola catalizzata (CST)
NOVEMBER 2008
51
Deep dive in the Diesel Particulate Filter
Diesel particulate filters represent the most
efficient technology to reduce particulate
matter (PM) from exhaust gas.
The PM is trapped within a wall flow filter.
Several ways of regeneration are possible to
avoid too high backpressures or even filter
blocking.
f additive supported systems (to reduce
particulate matter ignition temperature and
increase PM oxidation rate)
f catalyzed particulate filters can be used.
Regeneration require extensive system application and engine calibration work to ensure
reliable and durable system behavior at different ambient conditions and over long vehicle
driving distances.
Beside reliability and durability, minimal fuel consumption increase and excellent vehicle
drivability are the major development targets.
NOVEMBER 2008
52
DIESEL PARTICULATE FILTER REGENERATION METHODS
Yes
No
Fuel
Fuel Additive
Additive
Maintenance:
Maintenance: every
every 80.000
80.000 km
km
For-life
For-life solution
solution (~200.000
(~200.000 km)
km)
Front
Front Catalyst
Catalyst ++ Bare
Bare
Trap
Trap
Front
Front Catalyst
Catalyst ++
Bare
Bare Trap
Trap
Additive
Additive dosage
dosage System
System
Engine
Engine Management
Management
Strategies
Strategies
Front
Front Catalyst
Catalyst ++
Coated
Coated Trap
Trap
Coated
Coated
Trap
Trap
Engine
Engine Management
Management Strategies
Strategies
FAP
FAP PSA
PSA Concept
Concept
l l Complex
Complex and
and costly
costly
l l Ash
collection
Ash collection
⇒
⇒ filter
filter cleaning
cleaning every
every 80.000
80.000 km
km
l l Regeneration:
Regeneration: T<450
T<450 °C
°C (CeO
(CeO22))
l l Low
Low backpressure
backpressure
ll
ll
ll
Regeneration
Regeneration T~650
T~650 °C
°C
Low
Low back
back pressure
pressure
ll
ll
Regeneration:
Regeneration: T~600
T~600 °C
°C
Risk
Risk of
of poor
poor regeneration
regeneration
efficiency
efficiency (Catalyst-soot
(Catalyst-soot contact)
contact)
Risk
of
efficiency
drift
Risk of efficiency drift
(High
(High Temperature
Temperature of
of Regen.)
Regen.)
PM
PM Filtration
Filtration Efficiency
Efficiency >> 95%
95%
NOVEMBER 2008
53
FUEL ADDITIVE DOSING SYSTEM ( Peugeot , Ford, Hunday)
CERIO
NOVEMBER 2008
54
CATALYZED DPF : REGENERATION STRATEGY
La trappola catalizzata
richiede un innalzamento
della temperatura dei gas
attraverso AFTER+POST
Æossidazione degli HC/CO
nei catalizzatori a monte
del filtro
PRE
PILOT
AFTER
MAIN
POST
+
Modification of:
l
Pilot, Main Injection Timing
l
Injection Pressure
l
EGR
l
Boost Pressure
l
Air Flow (throttling)
ECU
C
T
Pre-cat
EGR Throttle
Valve Valve
Air Flow
Meter
Temperature
Sensor
Catalyst
Catalyst activation
activation
(T
>
300°C)
(T > 300°C)
Temperature
Temperature increase
increase
(>
600°C)
by
HC
(> 600°C) by HC addition
addition
(oxidation
reaction)
(oxidation reaction)
Temperature
Sensor
Catalyst Filter
NOVEMBER 2008
Pressure Drop
Sensor
55
Engine Control Architecture
Architettura del sistema di controllo
Modification of:
eValvPosObj
l
Air Flow (throttling)
Accelerator
Clutch
Brake l
Boost Pressure
ol ia
r
t
Gear
on opp
c
Key l
e ic
EGR
qu lo d
r
Cruise Control
o ol
Friction Torque T trrpm
Air Condition.
on
AirQ
rpm
tPosObj
Pboost
rpm
Boost
Control
User Interface
l
Indicated
+ Torque
Request
Engine
Efficiency
Split Pilot, Main
rpm
Auxiliary Torque
Request
l
Timing
External
Torque
Request
(Selespeed, ABS) Auxiliary
l
Injection Pressure
Request
NOVEMBER 2008
Split Fuel
Quantity
Qload
Request
Start Of
Injection
rpm
Prail
Prail
Control
eDuty
Air control
Controllo dell’aria
Air
Control
C
Effective
Torque
Request
EGR
Control
Throttle
Control
tDuty
bDuty
Qpil
Qpre
Qmain
Qaft
Qpost
SOIpil
SOIpre
SOImain
SOIaft
SOIpost
pDuty
Inverted
Injector
Model
ETpil
ETpre
ETmain
ETaft
ETpost
Combustion control
Controllo iniezione
Prail
Pressure control
Controllo pressione
56
REGENERATION :PHYSICAL MODEL
Complesse tecniche di controllo per determinare quando cominciare la rigenerazione
NOVEMBER 2008
57
The exhaust after treatment system WITH under floor TRAP
NOVEMBER 2008
58
Diesel Oxidation Catalyst
Diesel oxidation catalysts reduce HC and CO emissions
significantly. The conversion efficiency depends very much on the
catalyst temperature.
Furthermore, oxidation catalysts are specially formulated to meet
today's requirements for particulate matter (soluble part) reduction.
Main development trends for Diesel oxidation catalysts are:
Increased cells per square inch (CPSI)
Thin wall substrates
Close coupled catalysts
Lower light-off temperatures
Cell structures within metallic substrates
NOVEMBER 2008
59
Temperature downstream Pre-Cat during DPF regeneration
Per uno stesso tipo di autovettura si ha una grande
dispersione di dati
NOVEMBER 2008
60
Oxidation catalyst optimization (NEDC test with aged
components)
Quanto si può migliorare le prestazioni dei catalizzatori ossidanti
NOVEMBER 2008
61
DPF TYPES
NOVEMBER 2008
62
Close Coupled DPF
Close-Coupled: il più vicino possibile al motore
Close Coupled DPF has been selected as
most viable solution for Exhaust After
treatment
f Better thermal management (faster
regeneration)
improve regeneration efficiency, reduce
impact on the oil change interval
f Lower cost in comparison with Eu4 system
f Development of Second Gen DPF
f Improved performance at lower cost
NOVEMBER 2008
63
Fuel injection for Close-coupled DPF vs. Under floor DPF
Added Fuel Quantity for regeneration (g)
.
Under floor: sotto la scocca (quindi lontani dal motoreÆpiù combustibile per “scaldarli”)
Fuel injection Relative reduction
600
Underfloor DPF
500
Close-Coupled DPF
400
- 35%
- 28%
- 26%
300
- 43%
200
100
0
2100 rpm x 1.0 bar BMEP
( 30 km/h, II gear )
1500 rpm x 2.5 bar BMEP 1650 rpm x 4.5 bar BMEP 2350 rpm x 7.0 bar BMEP
( 50 km/h, IV gear )
( 70 km/h, V gear )
( 100 km/h, V gear )
Reduction of total after and post-injection quantities during DPF regeneration
Temperature inlet DPF: 620 °C, regeneration time: 10 min,
NOVEMBER 2008
64
NOVEMBER 2008
65
TRAP REGENERATION :Inlet DPF Temperature
Quanto conta la strategia di controllo sulla temperatura dei gas di scarico
Baseline
Baseline (w/o
(w/o Reg.
Reg.
Strategies)
Strategies)
With
With Regeneration
Regeneration
Strategies
Strategies
18
18
16
16
14
14
BMEP (bar)
12
10
180 km/h
400
8
160 km/h
300
140 km/h
6
BMEP (bar)
500
12
> 600°C
10
8
550
160 km/h
140 km/h
6
EUDC
180 km/h
600
EUDC
120 km/h
120 km/h
4
70 km/h
2
0
4
100 km/h
0
2000
3000
ENGINE SPEED (rpm)
NOVEMBER 2008
70 km/h
2
ECE
1000
100 km/h
4000
ECE
1000
2000
3000
4000
ENGINE SPEED (rpm)
66
BARE TRAP VS COATED TRAP

Comparison of a COATED over BARE soot filter for soot regeneration.
The multiple oxidation of NO to NO2 over the catalytic coating shows at
lower NO2/NO a clear benefit for the catalyzed system.
NOVEMBER 2008
67
DA EURO 5 a EURO 6
ATA 2006 :
Technologies towards Euro 6 Passenger Car Diesel Emissions Standards
R. Imarisio, D. Ivaldi, M.G. Lisbona, M.Tonetti Fiat Powertrain Technologies
NOVEMBER 2008
68
Strategies to meet Euro 6
Passenger car Mainstream: DPF, reduce NOx engine out
emissions, After treatment
0.025
Euro 4
2005
Step 2
Advanced Combustion
(PHCCI)
0.020
0.015
Step 1
(Conventional Combustion)
De-Nox
Aftertreatement
0.010
0.005
Euro 4
Technologies
+ DPF
Euro 5
Euro6
0.05
0.10
0.15
0.20
0.25
NOx (g / km)
NOVEMBER 2008
69
Strategy: to work towards Euro 6 Scenario”
ENGINE OUT EMISSION REDUCTION
f
f
f
f
f
f
IMPROVED INJECTION SYSTEM
ENHANCED CONVENTIONAL COMBUSTION
ENHANCED GLOW PLUG SYSTEM
IMPROVED EGR CYL TO CYL DISTRIBUTION
HIGH EFFICIENCY EGR COOLER with BY – PASS
EMISSIONS DISPERSION CONTROL
IMPROVEMENTS
CLOSED COUPLED DPF
ENGINE OUT EMISSION REDUCTION
f LOW PRESSURE EGR
f HOMOGENEOUS CHARGE COMPR. IGNITION
NEW !!
NOX AFTER TREATMENT
f SCR
f DeNOxTRAP
f DNPR
NOVEMBER 2008
70
Euro 6 Engine Management System - New Functions
Enhanced air system management
f
f
f
f
f
EGR cooler by–pass
EGR DC-motor valve
Electrical Throttle Valve
Variable Geometry Turbine with actuator position sensor
Variable swirl management
NOX management strategies
f
f
f
Long-route (or low-pressure) EGR management
PHCCI
Selective catalytic reaction ( UREA Addition)
La riduzione degli NOX è la
ragione della ulteriore
modifica dei motori diesel a
partire dal 2012
f
f
f
f
Enhanced Glow Plug management (low voltage)
Closed-loop smoke control in transient
Multiple injection
Injector Rate Shaping (IRS)
DPF strategy improvement
f
f
Low O2 regeneration for advanced DPF (closed coupled, cordierite)
Multi post injection
Driveability
f
Energy Shaking Driveline Damping (ESDD)
NOVEMBER 2008
71
IMPROVED INJECTION SYSTEM
IM
NOVEMBER 2008
OV
R
P
TS
N
E
EM
72
COMPRESSION RATIO REDUCTION
IM
OV
R
P
TS
N
E
EM
Perché si può aumentare la pressione di sovralimentazione
NOVEMBER 2008
73
ADVANCED DOC (Diesel Oxidation Catalyst)
IM
NOVEMBER 2008
OV
R
P
TS
N
E
EM
74
DPF EVOLUTION
IM
NOVEMBER 2008
OV
R
P
TS
N
E
EM
75
TAIL PIPE EMISSION REDUCTION
LOW PRESSURE (LONG ROUTE) EGR
NEW COMBUSTION SYSTEMS
f HOMOGENEOUS CHARGE COMPRESSION IGNITION (HCCI): la miscela
aria-combustibile che si auto-accende è omogeneaÆdetonazione
controllata)
f PARTIAL (MILD) HOMOGENEOUS CHARGE COMPRESSION IGNITION
(PHCCI oppure PCCI): buona parte del combustibile brucia dopo aver
formato una miscela omogenea, la restante parte brucia in modo diffusivo)
NOVEMBER 2008
76
EGR LAY OUT COMPARISON
W
E
N
VGT
EGR
λ
Air
cleaner
C
VGT
C
DPF
T
AFM
Pre-cat
T
AFM
POil
EGR
by-pass
valve
Cat
EGR cooler
Intercooler
Cat
Intercooler
EURO 6
Air
cleaner
λ
DPF
P/Tboost
EGR
valve
Swirl Flaps
Inlet
Throttle
NOVEMBER 2008
EGR
mixer
P/Tboost
EURO 4 / EURO 5 EGR
77
!!
LOW PRESSURE /LONG ROUTE EGR
L’idea:
Aumentare EGR a pari A/F
Vantaggi:
•Riduzione della temperatura della carica senza EGR cooler (gas esausti presi
dopo la turbina)
•EGR pulito (perché a valle del DPF)
•Distribuzione più uniforme dell’EGR (più tempo per miscelarsi)
•Maggior efficienza turbo (portate elaborate maggioriÆmeno rischio pompaggio)
•Si può usare EGR anche durante la rigenerazione
Problemi:
•Erosione e corrosione del compressore e dell’intercooler
•Tempi di risposta del sistema lunghi
•Aumento HC e CO
NOVEMBER 2008
78
THE CHARGE TEMPERATURE MANAGEMENT
Nelle partenze a freddo EGR deve essere caldo,dopo freddo
EGR caldo ottenibile mediante aumento dell’incrocio (se ci sono sistemi VVA-VVT)
EGR TEMPERATURE REQUIREMENTS
cold
HOT INTERNAL EGR Controlled
Through
Conventional EGR
hot
VERY COLD EXTERNAL EGR
Available Through
LOW PRESSURE EGR LOOP
NOVEMBER 2008
79
ADVANCED COMBUSTION
W
E
N
HCCI
PHCCI
CLOSED LOOP COMBUSTION
NOVEMBER 2008
80
!!
HCCI / PH CCI : GLOSSARIO
NOVEMBER 2008
81
Integrated combustion strategy (AVL source)
Secondo AVL un’iniezione ritardata (Late Injection) consente una combustione
ottimale nelle condizioni operative del ciclo Europa
Conventional
NOVEMBER 2008
82
HCCI ( Homogeneous charge compression ignition)
strategies
Lecture from ATA 2006
Siracuse conference
NOVEMBER 2008
83
A DIFFICULT ROAD MAP
NOVEMBER 2008
84
The early injection strategy
Il problema principale dell’iniezione anticipata (Early Injection) è il RUMORE e
il CONSUMO
NOVEMBER 2008
85
The early injection associated to a variable CR
Si può provare ad abbassare il rapporto di compressione
NOVEMBER 2008
86
The split injection as an alternative
Si può iniettare dopo TDC (late Injection) in 2 fasi (split injection)
NOVEMBER 2008
87
The split injection as an alternative
NOVEMBER 2008
88
ADVANCED COMBUSTION RESULTS
*) Conventional DOC
*
NOVEMBER 2008
*
89
CONCLUSIONS ON PHYSICS
The early injection strategy : a way to reduce engine out emissions
f But a limited operating area which could be widen by a variable CR
f The split injection as an alternative
The “mild HCCI” : a trade off between homogeneous and diffusive
combustion
f The fully premixed combustion is limited by noise and HC above quite
moderate loads
f the variable CR could be a long term solution
The “mild HCCI” - ie a split injection strategy associated to a fairly
conventional combustion chamber design - allows to reach both
very low NOx and particulates levels
HC, fuel consumption and transients must be carefully optimized
with a recursive calibration and combustion chamber design
The mixed controlled combustion strategy PHCCI / STRATIFIED
plays a major role
NOVEMBER 2008
90
COME CONTROLLARE UNA COMBUSTIONE HCCI
W
E
N
OPEN LOOP : possibile con una mappatura ,
f
la robustezza della calibrazione può essere messa dura prova dalla
dispersione dei componenti a zero km e nel tempo
CLOSED LOOP : con un sensore di combustione adatto
NOVEMBER 2008
91
!!
COMBUSTION CLOSED LOOP CONTROL
Combustion index
evaluation
Combustion
Control
(split / timing)
Intake
Control
Acquisition
EMS
Sensor
NOVEMBER 2008
92
NOX AFTER TREATMENT
LOAD FACTOR IMPORTANCE
f SCR (Selective Catalyst Reduction)
f DENOx (Trappola per NOx)
f DNPR (Diesel Particulate-NOx Reduction)
NOVEMBER 2008
93
Engine tail emission are increasing with load factor (LF) , as
typically a Diesel engine is more efficient on high load and thus is
working in an higher temperature range
f Whereas the combustion temperature may be reduced with an
appropriate use of EGR ( High and low temperature), nevertheless such
technology is not suitable for Heavy Truck, and Mid truck segment,
where consumption penalties cannot be accepted
f In such a condition SCR is today the chosen technology
LF increasing
NOVEMBER 2008
Un risvolto negativo del down-sizing: nel ciclo guida
aumenta il carico (espresso dal fattore di carico:
Load Factor)Æaumenta temperatura di
combustione Æaumentano NOx
Quando non si possono utilizzare alti EGR
(problemi di consumo, fondamentale per i camion)
o quando l’EGR non basta, si deve ricorrere a
sistemi di post-trattamento degli NOx (SCR)
94
On the contrary, low Engine LF Passenger car may reduce NOx
emission , with some ( 5%) fuel penalties working on the
combustion temperature
f In such a condition car maker use 3 different technologies alone or in
combination
EGR standard
Low temperature ( often reported as Long Route EGR)
PHCCI :Premixed Homogeneous Charge Compression Ignition
Under this point of view large engine displacement will be more
favorable to get lower LF thus achieving lower NOX emission
Commercial vehicle are in between , depending from the actual LF
the are working on the homologation cycle
Of course the LF is the key parameter which ,in combination with
the allowed emission level make car maker chose the
cost/performance trade off technology.
Per le autovetture in Europa si pensa di poter fare a meno di sistemi di post-trattamento NOx
NOVEMBER 2008
95
NOX AFTER TREATMENT
f SCR

I componenti
Le strategie
Punti critici ( design & reliability)
NOVEMBER 2008
96
Paragone EUROPA USA
Dati in g/km
CO
NOx
PM
HC
EURO 5
0,5
0,180
0,005
0,068
EURO 6
0,5
0,080
0,005
0,068
LEV/ULEV 50 k ml
2.1 / 1.1
0,031
0.00
0,0094 / 0,005
LEV/ULEV 120 k ml
2.6 / 1.3
0,044
0,0063
0,0110 / 0,007
Questa diminuzione rende di fatto necessaria la adozione di misure anti NOx
Questa differenza costringe alla adozioni di sistemi di abbattimento differenti dell’ NOx in USA e EU
Negli stati uniti l’uso della SCR diviene , ad oggi l’unico mezzo di controllo dell’NOx:
-Mercedes, Audi sono già sul mercato con l’additivo AD blue
NOVEMBER 2008
97
MAIN DIFFERENCES
Level are more severe in USA
f EURO 6 ( EUDC)
f USA( FTP) Tier 2 Bin 5
80 mg /km
31 mg /km 50kml
44 mg/km 120kml
f JAPAN
80 mg/km
USA limits are more severe and furthermore the used USA driving
cycle is inducing higher NOx emissions due to an Higher Engine
Load factor
NOVEMBER 2008
98
CHEMISTRY
NOVEMBER 2008
99
SCR : NOx Control Principle
PM
HC
N2
NO2
CO2
NO
NH3
H2O
PM
NOVEMBER 2008
100
SCR architecture
Supply Module
Reagent Level Sensor
Reagent
Pressure
Regulator
AdBlue
TANK
Reagent
Temperature
CAN
Alimentatore NOx
Pressure Sensor
Engine
Injector
Nox Sensor
T
OXI CAT
Sonda UEGO
NOVEMBER 2008
DPF
MIXER
Temperature Sensor
SCR
Temperature Sensor (SCR)
101
UREA FREEZING POINT
NOVEMBER 2008
102
Technical problems with automotive SCR units
In order to ensure that the SCR unit remains free from
contaminants, correct materials of construction must be used for
both storage and dispensing. Manufacturers of the SCR unit have
specified that, without using compatible materials of construction,
ions can be passed from the dispensing materials into the porous
head on the SCR unit. This can render the SCR unit ineffective and
reduce its life expectancy by more than 60%.
Another common problem with all SCR systems is the release of
unreacted ammonia referred to as ammonia slip. Slip can occur
when catalyst temperatures are not in the optimal range for the
reaction or when too much ammonia is injected into the process.
Additional oxidation catalyst, so called slip catalyst, is typically
fitted downstream an SCR system to reduce such slip.
Another common problem especially in passenger cars applications
is relatively low temperature of exhaust gas resulting in low SCR
catalyst monolith temperature outside optimal range. This is a
problem especially in cold-start conditions.
NOVEMBER 2008
103
AdBlue
AdBlue is the registered trademark for AUS32 (Aqueous Urea Solution
32.5%) and is used in selective catalytic reduction
As the name AUS32 would suggest, it is a 32.5% solution of high-purity
urea in demineralised water that is clear, non-toxic and is safe to handle.
However, it can be corrosive for some metals and must be stored and
transported with the correct materials. The AdBlue trademark is currently
held by the German Association of the Automobile Industry who ensure
quality standards .
AdBlue is carried onboard SCR-equipped trucks and buses in specially
designed tanks and is dosed into the SCR system at a rate equivalent to 35% of diesel consumption. This low dosing rate ensures long refill periods
and minimizes the tank’s impact on chassis space.
All European truck manufacturers currently offer SCR equipped models,
and the future Euro VI emission standard is set to reinforce the demand for
this technology. SCR systems are sensitive to potential chemical impurities
in the urea solution.
NOVEMBER 2008
104
NOX AFTER TREATMENT
f Lean NOx TRAP (LNT, DeNOx)
L’idea è quella di utilizzare una sorta di filtro che accumula gli NOx durante il normale
funzionamento del motore; una volta pieno, il filtro viene rigenerato facendo funzionare il
motore con dosatura stechiometricaÆalte temperature dei gas, bassa concentrazione di
Ossigeno, presenza di CO e H2
Under lean conditions (the normal operating mode of a Diesel engine), the catalyst
promotes NOx adsorption as illustrated by reactions (1) and (2), where M is the NOx
adsorbing element, MO is the stable oxidized form of the element, and MNO3 is the
stable NOx containing compound formed by element M.
The stability of the nitrates formed by reaction (2) dictate the high temperature
operation limit of the LNA formulation under a given set of conditions.
2NO + O2 → 2NO2 (1)
NO2 + MO → MNO3 (2)
Under fuel-rich conditions, the catalyst promotes the reverse reaction i.e. release of
the stored NOx from the nitrate phase, reaction (3), and its reduction to form N2,
reaction (4).
MNO3 → MO + ½O2 + NO (3)
NO + CO / H2 → ½N2 + CO2 / H2O (4)
NOVEMBER 2008
105
Lean NOx Trap
LNT deve stare a monte del DPF
NOVEMBER 2008
106
NOx CONVERSION EFFICIENCY
NOVEMBER 2008
107
NOx CONVERSION EFFICIENCY BY AGING
Con l’invecchiamento il rendimento
peggiora
NOVEMBER 2008
108
A DOC MAY BE NECESSARY
Diesel LNA catalysts demonstrate the ability to remove significant amounts
of NOx from vehicle exhausts.
f A high level of NOx conversion (68%) was demonstrated over the MVEG cycle
without a large increase in the HC or CO emissions.
f Extra oxidation catalyst downstream of the LNA, is necessary in the position
where a catalysed particulate filter would be normally be used.
f It was demonstrated that the LNA catalyst is highly durable to thermal exposure,
and recovers well from exposure to sulfur.
Control of a LNA system is critical.
f There is a critical light-off temperature that limits the low-temperature
performance (particularly for regeneration).
f There is a high temperature operational limitation on performance caused by the
increasing instability of the stored NOx as temperature increases.
f Thermal control and design of the system is particularly important.
Rich purge and desulfation have to be triggered at certain times to keep the
system performance high.
Accurate models and / or sensors to ensure the system remains at high
performance in all driving conditions.
NOVEMBER 2008
109
Il tipo di sistema dipende dal fattore di carico:
NOVEMBER 2008
110
DNPR
L’idea è quella di utilizzare un unico componente in grado di intrappolare gli NOx ed il
particolato, e di ossidare CO e HC.
E’ stato sviluppato da Toyota, richiede una gestione del motore molto complessa
NOVEMBER 2008
111
SUMMARY
Moderni sistemi di abbattimento degli inquinanti nei Diesel
EURO 5
EURO 6
NOVEMBER 2008
112
IMPACTS ON EXHAUST SYSTEMS FOR PC /LCV DIESEL
ENGINE APPLICATION
LOW load factor
Passenger cars Seg. A, B, C
Pre Cat
EURO4
01.09.05
Closed Coupled DPF
EURO5
01.09.09
EURO6
01.09.14
MEDIUM load factor
HIGH load factor
Passenger cars Seg. C, D
Passenger cars Seg. D, E and LCV
Pre Cat
+
Under Floor DPF
Pre Cat
+
Under Floor Oxi Cat
+
Under Floor DPF
Closed Coupled DPF
+
EGR Low Pressure
(if necessary)
SCR System
Closed Coupled DPF
+
EGR Low Pressure
Closed Coupled DPF
+
EGR Low Pressure
SCR System
OR
SCR System
NOVEMBER 2008
113
CROSS IMPACT VEHICLE /NOx LIMITS/TECHNOLOGY
Condition
Vehicle
Load
Factor
Homologation
USA
Technology
Europe
Truck
high
Dedicated procedure
100%
SCR
Mid-size Truck >3.5t
High
Dedicated procedure
100%
SCR
100%
SCR
EUDC
70%
SCR
80 mg/km
30%
EGR
All USA
diesel import
&
Export
SCR
Seg A/C
EGR
Seg DEG
SCR
ALL
Light Duty <3.5 t
NOVEMBER 2008
31mg/ km
High
med
ALL
Passenger car
FTP
Med
low
FTP
31mg/ km
EUDC
80 mg/km
114
ROAD MAP FOR NON PC AFTER TREATMENT
NOVEMBER 2008
115