Comparison of Chasis Dynamometer In-Use Emissions with Engine Dynamometer FTP Emissions for Three Heavy-Duty Diesel Vehicles 982653

Three heavy-duty vehicles (two buses and a truck) were tested on a chassis dynamometer and the engines were removed and tested on an engine dynamometer. Two 1993 DDC Series 50 and one 1993 Navistar DTA-466 were the engine models tested. The objective of this testing was to compare in-use emissions from vehicles with engine FTP emissions, and begin to evaluate and begin to evaluate the relationship between emissions on these two tests. Engine testing results (heavy-duty FTP) show emissions above certification levels for the two bus engines, especially for NOx, however the truck engine met the emissions standards. Chassis testing was performed using the Central Business District cycle and the EPA Urban Dynamometer Driving Schedule for Heavy-Duty Vehicles (heavy-duty transient truck or HDT cycle). There was a substantial difference in emissions for these two cycles on a g/mi basis, however both cycles gave essentially the same gaseous emissions on a g/gal of fuel consumed basis. Chassis test inertial weight had a significant effect on g/mi emissions of all pollutants, however on a g/gal basis, emissions were not a function of inertial weight except for PM, which was a weak function of inertial weight. The data were used to estimate bhp-h/mi factors for converting engine test data to the g/mi basis normally employed in pollutant inventory estimation. Overall the calculated factors were significantly different from those currently employed by EPA. When both engine test and chassis test data are converted to a g/gal basis, it was found that both tests produce approximately the same emissions. The use of fuel consumption based conversion factors therefore, may prove more accurate than the current approach.


Subscribers can view annotate, and download all of SAE's content. Learn More »


Members save up to 16% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:

Application of the New City-Suburban Heavy Vehicle Route (CSHVR) to Truck Emissions Characterization


View Details


Fuel-Borne Catalyst Assisted DPF regeneration on a Renault Truck MD9 Engine Outfitted with SCR


View Details


Modular Trap and Regeneration System for Buses, Trucks and Other Applications


View Details