semtech® efm-hs

Emissions
Measurement
Solutions
SEMTECH EFM-HS
®
High Speed Exhaust Flow Meter
Sensors’ High Speed Exhaust Flow Meter, the SEMTECH EFM-HS, adds
enhanced capabilities and features to the product line. With a sampling
rate of up to 2500 Hz and four differential pressure transducers, the EFMHS accurately measures every forward and reverse flow pulsation from
idle to maximum flow rate, and properly accounts for these pulsations
in the exhaust flow determination. This is an advantage over low speed
exhaust flow meters which are susceptible to measurement error from
high frequency pulsations. The EFM-HS also offers other performance
enhancements and convenience features that set it apart from the
competition.
Mass flow rate accuracy and linearity of the SEMTECH EFM-HS exceeds the
US and European performance standards over a 50:1 turndown ratio. The
EFM-HS can be used to measure exhaust flow rate from both spark and
compression ignition engines, as a stand-alone device, or in conjunction
with the emissions measurements of the SEMTECH-DS or other gas
analyzers, to compute real-time mass emissions.
Sensors, Inc. • 6812 State Rd. • Saline, Michigan 48176 • PH:(734) 429-2100 • FX:(734) 429-4080 • www.sensors-inc.com
Sensors Europe GmbH • Feldheider Str. 60 • 40699 Erkrath • Germany • PH: +49 (0) 2104-14188-0 • FX: +49 (0) 2104-14188-14
SEMTECH EFM-HS
High Speed Exhaust Flow Meter
System Features and Benefits
High Speed Sampling: The EFM-HS internally samples the
differential pressure channels at up to 2500 Hz, accounting for
every pressure pulse from an engine, from idle to maximum rpm.
Standard output rate is 5 Hz.
Embedded Calibration: Calibration coefficients embedded in the
flow tube electronics are automatically recognized on connection,
enabling multiple tubes to be used with one control module.
Multiple Tube Sizes: Eight flow tube sizes accommodate engines
from less than 0.8L displacement up to 24L.
Back Purge: A software controlled back purge pump is included
in the flow tube assembly along with solenoids that route
high pressure air backward through the pitot tube, purging
contaminants and any condensation in the pressure lines. No
dismantling is required.
Auto Zero: With a single software command, internal solenoids
open the pressure sensors to ambient air, allowing fast and easy
zeroing while the engine is still operating.
Weatherproof Construction: The unit can be used off-road and in
other harsh environments. All components are weatherproof to
IP54 (NEMA 3) standards.
Heated Components: The averaging pitot tube and pressure
lines are heated at the flow tube assembly in order to prevent
condensation and freezing in cold weather. The differential
pressure sensors are housed in a temperature controlled manifold
in the control module for added stability.
Optional Configurations
High Speed Data Acquisition: Data output rate of 500 Hz is
available.
Stand-Alone Configuration: SENSOR Tech-EFMHS application
enables system operation from a Windows environment.
Customized Interface: Sensors can develop a customized
device driver to interface with various host systems.
Sample Screen from SENSOR Tech-EFMHS
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Sensors, Inc. • 6812 State Rd. • Saline, Michigan 48176 • PH:(734) 429-2100 • FX:(734) 429-4080 • www.sensors-inc.com
Sensors Europe GmbH • Feldheider Str. 60 • 40699 Erkrath • Germany • PH: +49 (0) 2104-14188-0 • FX: +49 (0) 2104-14188-14
The Technology
SEMTECH EFM-HS
High Speed Exhaust Flow Meter
Operating under the Bernoulli principle, the
SEMTECH EFM-HS uses four high performance,
differential pressure transducers, each with two
ranges of amplification. The transducers sample
continuously at up to 2500 Hz, measuring every
pressure pulse from an engine. The sensors are
housed in a heated manifold, eliminating thermal
drift. The eight combined differential pressure
ranges span nearly five orders of magnitude,
allowing accurate measurements over a wide
range of flow rates. The smallest transducer range
is 0.025 kPa with a resolution of 5x10-5 kPa, while
the highest range is 16.5 kPa.
A proprietary algorithm computes a spline fit of the
eight high speed differential pressure signals, and
calculates a running square-root average that is used
to determine output flow rates at 5 Hz (500 Hz with
the high speed option). The high speed sampling
and symmetrical design of the averaging pitot tube
provides the EFM-HS with the ability to accurately
measure reverse flow due to engine pulsations, and
to properly account for this phenomenon in the
average flow rate determination.
Sensors, Inc. • 6812 State Rd. • Saline, Michigan 48176 • PH:(734) 429-2100 • FX:(734) 429-4080 • www.sensors-inc.com
Sensors Europe GmbH • Feldheider Str. 60 • 40699 Erkrath • Germany • PH: +49 (0) 2104-14188-0 • FX: +49 (0) 2104-14188-14
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SEMTECH EFM-HS
High Speed Exhaust Flow Meter
SEMTECH EFM-HS Available Sizes
Flow Tube Outer Diameter
in
mm
1
25
1.5
38
2
51
2.5
64
3
76
4
102
5
127
6
152
25 (37)
635 (940)
30 (45)
762 (1143)
36 (54)
914 (1372)
Flow Tube Length (Length including extension)
in
mm
20 (26)
508 (660)
20 (26)
508 (660)
20 (26)
508 (660)
25 (32.5)
635 (825)
25 (34)
635 (864)
400°C flow rates fall between the red markers
100°C flow rates extend the full length of the line
Exhaust temperature range:
-5 to 700°C standard construction (higher temp. capability available upon request)
Exhaust temperature accuracy:
± 1% of reading or ± 2°C, whichever is greater
Flow measurement linearity:
< 1.0% of full scale (Exceeds 1065 Subpart D & ISO 16183 standards)
Flow measurement accuracy:
± 2% of reading or ± 0.5% of full scale, whichever is greater
Warm up time:
< 5 minutes at 20°C ambient
System response time:
< 2 ms
Data rate:
5 Hz standard
High Speed option data rate:
500 Hz (100 Hz display rate)
Resolution:
0.1 SCFM
Power requirements:
12VDC , 30W; 110VAC
Communications:
RS 232
Control module dimensions:
36cm x 18cm x 10cm (LxDxW)
Control module weight:
4kg (9 lbs)
381.0mm
69.0mm
49.0mm
Diameter*
Length*
* See table above.
NOTE: Accurate measurements require adequate straight pipe
length prior to the exhaust entering the measuring pitot. This is
ensured with our tube extension kits, referenced in the length
specifications in the chart above.
NOTE: Specifications are subject to change without notice. While due caution has been exercised in the production of this document, possible errors and omissions can occur.
Rev. 20160518
4
Sensors, Inc. • 6812 State Rd. • Saline, Michigan 48176 • PH:(734) 429-2100 • FX:(734) 429-4080 • www.sensors-inc.com
Sensors Europe GmbH • Feldheider Str. 60 • 40699 Erkrath • Germany • PH: +49 (0) 2104-14188-0 • FX: +49 (0) 2104-14188-14