Demonstration of a heavy-duty vehicle chassis screening test for compliance testing heavy-duty engines. Final report

Emissions testing of new heavy-duty engines is performed to ensure compliance with governmental emissions standards. This testing involves operating the engine through the heavy-duty diesel transient Federal Test Procedure (FTP). While in-use engine emissions testing would be beneficial in aiding regions to meet standards dictated by the Clean Air Act, the process of removing the engine from the vehicle, fitting it to an engine dynamometer, testing, and refitting the engine in the chassis, combined with costs associated with removing the vehicle from service, is prohibitively expensive. A procedure for screening engine emissions testing with the engine in the vehicle using a chassis dynamometer was developed to mimic the FTP. Data from two engines and vehicles (a 195 hp Navistar T 444E in a single axle straight truck and a 370 hp Cummins N-14 in a tandem drive axle tractor) is presented as well as correlation between engine and chassis emissions tests. Also included was data gathered to gauge the effects of engine tampering and malfunctioning on emissions levels. It was concluded that engine and chassis emissions levels were well correlated with respect to oxides of nitrogen, but less well so with respect to particulate matter.