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AMMONIA EMISSIONS FROM THE EPA'S LIGHT DUTY TEST VEHICLE
Citation:
Shores*, R C., J. T. Walker, M. O. Rodgers, J. Pearson, AND R. B. McCulloch. AMMONIA EMISSIONS FROM THE EPA'S LIGHT DUTY TEST VEHICLE. Presented at International Fall Fuels and Lubricants Meeting and Exhibition, San Antonio, TX, 9/24-27/01.
Description:
The paper discusses measurements of ammonia (NH3) emissions from EPA's light duty test vehicle while operated on a dynamometer. The vehicle's (1993 Chevrolet equipped with a three-way catalyst) emissions were measured for three transient (urban driving, highway fuel economy, and hard acceleration) cycles and steady state operation. Previous research showed that NH3 is predominantly emitted from vehicles with a catalyst (three-way or dual-bed). The normal operation of the vehicle's catalyst is to reduce nitrogen oxides (NOx) to nitrogen (N2) and oxygen (O2). The reduction of NOx to NH3 would have to occur during periods of operation when insufficient O2 is available. NH3 emissions were measured during fuel-rich/reduced-O2 conditions (opern-loop control scheme), and the results indicated that NH3 production is correlated to combustion conditions. The results also indicated that the amount of NH3 produced correlates with the amount of time that the vehicle remains in the open-loop control scheme. The significance of this finding is that NH3 production can be predicted for a fleet based on the frequency of enrichment of vehicles equipped with a three-way catalyst. The results also provide a way to determine the location of roadway links and/or specific locations whereNH# production can ber anticipated based on predicted engine power.