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Evaluating Real-World Fuel Economy on Heavy Duty Vehicles using a Portable Emissions Measurement System
Technical Paper
2006-01-3543
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
Current SAE practices for evaluating potential improvements in fuel economy on heavy-duty vehicles rely on gravimetric measurements of fuel tanks. However, the recent evolution of portable emissions measurement systems (PEMS) offers an alternative means of evaluating real-world fuel economy that may be faster and more cost effective. This paper provides a direct comparison of these two methods based on a recent EPA study conducted at Southwest Research Institute. More than 228 on-road tests were performed on two pairs of class 8 tractor-trailers according to SAE test procedure J1321 in an assessment of various chassis components designed to reduce drag losses on the vehicle. During these tests, SEMTECH-Dâ„¢ portable emissions measurement systems from Sensor's, Incorporated were operating in each of the vehicles to evaluate emissions and to provide a redundant measure of fuel economy. These measurements showed excellent correlation to the gravimetric results with a coefficient of determination greater than 0.98 and nearly identical regression slopes for three of the four trucks. One truck had a series of suspect data toward the end of the study that biased the regression slope higher by 4%. Measurement variability also compared favorably between the two test methods. The average coefficient of variation based on the three repeat laps performed on every test segment was 2.98% for the gravimetric measurements and 3.26% for the SEMTECH-D measurements at a 95% confidence interval. These results all support the use of SEMTECH-D as a viable alternative to the gravimetric measurements for heavy-duty in-use fuel economy determination.
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Ensfield, C., Bachman, L., Erb, A., and Bynum, C., "Evaluating Real-World Fuel Economy on Heavy Duty Vehicles using a Portable Emissions Measurement System," SAE Technical Paper 2006-01-3543, 2006, https://doi.org/10.4271/2006-01-3543.Also In
References
- SAE International Joint TMC/SAE Fuel consumption test procedure - Type II SAE Surface Vehicle Recommended practice J1321 1986
- Test Procedures and Equipment June 13 2005 70 133 40534 40560 U.S. Environmental Protection Agency
- Environmental U.S. Protection Agency, Assessments and Standards Division In-Use Testing Program for Heavy-Duty Diesel Engines and Vehicles -- Technical Support Document 2005
- SAE International Constant Volume Sampler System for Exhaust Emissions Measurement SAE Surface Vehicle Standard J1094 1992