The Potential for Achieving Low Hydrocarbon and NOx Exhaust Emissions from Large Light-Duty Gasoline Vehicles

Two large, heavy light-duty gasoline vehicles (2004 model year Ford F-150 with a 5.4 liter V8 and GMC Yukon Denali with a 6.0 liter V8) were baselined for emission performance over the FTP driving cycle in their stock configurations. Advanced emission systems were designed for both vehicles employing advanced three-way catalysts, high cell density ceramic substrates, and advanced exhaust system components. These advanced emission systems were integrated on the test vehicles and characterized for low mileage emission performance on the FTP cycle using the vehicle's stock engine calibration and, in the case of the Denali, after modifying the vehicle's stock engine calibration for improved cold-start and hot-start emission performance. The advanced emission systems were aged for 220 hours using an accelerated, engine dynamometer aging schedule and then re-evaluated for FTP emissions on both vehicles using the F-150's stock engine calibration and the Denali's modified engine calibration strategy. The engine-aged, advanced emission systems of both vehicles produced ultra-low hydrocarbon and NOx emissions at exhaust levels significantly below California's 120,000 mile LEV II ULEV emission standards.