Record Display for the EPA National Library Catalog


Main Title The vehicle road load problem : an approach by non-linear modeling /
Author Thompson, Glenn D.
CORP Author Environmental Protection Agency, Ann Arbor, Mich. Standards Development and Support Branch.
Publisher U.S. Environmental Protection Agency, Office of Air and Waste Management, Office of Mobile Source Air Pollution Control, Emission Control Technology Division, Standards Development and Support Branch,
Year Published 1975
Report Number LDTP-75-2
Stock Number PB-270 788
OCLC Number 713646426
Subjects Dynamometer ; Trucks--Pollution control devices
Additional Subjects Motor vehicles ; Exhaust emissions ; Dynamometers ; Measuring instruments ; Air pollution ; Exhaust gases ; Mathematical models ;
Internet Access
Description Access URL
Library Call Number Additional Info Location Last
ELCD  EPA LDTP-75-2 NVFEL Library/Ann Arbor, MI 04/25/2011 DISPERSAL
NTIS  PB-270 788 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation [i], 27, [2] p. : charts ; 28 cm.
A method to accurately characterize the road experience of the vehicle is a prerequisite for accurate dynamometer testing. In the usual coast down technique, the vehicle road load force is calculated from a numerical derivative of the speed versus time measurements. This study significantly improves the coast down technique by eliminating the differentiation of the speed-time data while maintaining the ability to treat the forces on the vehicle as a general quadratic function of vehicle speed. A model equation for the forces on a freely decelerating vehicle is constructed; this equation is analytically transformed into an expression for the speed of the freely decelerating vehicle as a function of time. This intrinsically non-linear equation is then computer fitted to the speed versus time data recorded from the vehicle. Road load measurements results by this method are compared with results by the drive shaft torque method.
Cover title. Includes bibliographical references (p. [29]).