Sensors’ High Speed Exhaust Flow Meter, the SEMTECH EFM-HS, replaces our EFM 2 and adds exciting capabilities and features to the product line. With a sampling rate of up to 2500 Hz and four, dual stage differential pressure transducers, the EFM-HS 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 a tremendous advantage over low speed exhaust flowmeters which are susceptible to measurement error from high frequency pulsations. The EFM-HS also offers a long list of other performance enhancements and convenience features that set it apart from the competition. Can be used either on-board or in a test cell.

 

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.

Exhaust temperature range:	-5°C to700°C standard, 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 and 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; 500 Hz with High Speed Option (100 Hz display rate)
Resolution:	0.1 SCFM
Power requirement:	12 VDC, 30 W; 110VAC
Communications:	RS232
Control module dimensions:	36cm x 18cm x 10cm (LxDxW)
Control module weight:	4 kg (9 lbs)

 

Recommended Application: Engine Size (L) & Type
Gas Diesel	< 1* < 0.8	< 2* < 1.5	< 2 < 1.5	2 - 5 1.5 - 4	> 5 4 - 6	- 6 - 12	- 12 - 18	- > 18
Flow Tube Outer Diameter
in mm	1 25	1.5 38	2 51	2.5 64	3 76	4 102	5 127	6 152
Flow Tube Length
in mm	30 762	30 762	20 508	25 635	30 762	40 1016	50 1270	60 1524
Backpressure	Flow Rate at 200°C, SCFM (m3/min)
10" H20 2.5 kPa	67 (1.9)	109 (3.1)	175 (4.9)	425 (12.0)	600 (17.0)	1100 (31.2)	1700 (48.1)	2380 (67.3)
15" H20 3.75 kPa	83 (2.4)	146 (4.1)	215 (6.1)	550 (15.6)	775 (22.0)	1350 (38.2)	2100 (59.5)	2940 (83.3)
Backpressure	Flow Rate at 400 °C, SCFM (m3/min)
10" H20 2.5 kPa	56 (1.6)	91 (2.6)	147 (4.2)	356 (10.0)	503 (14.3)	922 (26.2)	1425 (40.3)	1995 (56.4)
15" H20 3.75 kPa	69.9 (2.0)	122 (3.5)	180 (5.1)	461 (13.1)	649 (18.4)	1132 (32.0)	1760 (19.9)	2465 (69.8)