Application of the New City-Suburban Heavy Vehicle Route (CSHVR) to Truck Emissions Characterization 1999-01-1467
Speed-time and video data were logged for tractor-trailers performing local deliveries in Akron, OH. and Richmond, VA. in order to develop an emissions test schedule that represented real truck use. The data bank developed using these logging techniques was used to create a Yard cycle, a Freeway cycle and a City-Suburban cycle by the concatenation of microtrips. The City-Suburban driving cycle was converted to a driving route, in which the truck under test would perform at maximum acceleration during certain portions of the test schedule. This new route was used to characterize the emissions of a 1982 Ford tractor with a Cummins 14 liter, 350 hp engine and a 1998 International tractor with a Cummins 14 liter, 435 hp engine. Emissions levels were found to be repeatable with one driver and the driver-to-driver variation of NOx was under 4%, although the driver-to-driver variations of CO and PM were higher. Emissions levels of NOx for the Ford tractor at a test weight of 46,400 lb. using the CSHVR were comparable with values obtained using the WVU 5 mile route and the EPA Urban Dynamometer Driving Schedule for Heavy Duty Vehicles (“Test D”). The PM emissions were slightly higher for the CSHVR than the 5 mile route and Test D. The effect of test weight on emissions, in units of mass/distance, was assessed using the International tractor with the CSHVR at 26,000, 36,000 and 46,400 lb. test weights. Variation of all regulated exhaust emissions was small between test weights, although the CO2 level reflected the additional energy used at higher weights. The small variation in regulated emissions may be attributed to the fact that in all three cases, the route called for full power operation of the vehicle, and that any PM puff associated with gear shifting would be similar. It is concluded that the CSHVR represents a useful and realistic test schedule for truck emissions characterization.