Development of a method for determining exhaust emissions and fuel consumption of vehicles in on-road operation

Interest in the contribution of automobiles to air pollution has caused review of the current emissions testing procedures in use in the United States and elsewhere. Specifically, concern has arisen that current mobile source inventory tools do not adequately model actual driving behavior and therefore do not accurately predict the fuel consumption and emissions from vehicles. By including the actual driving conditions vehicles experience during operation, a database of emissions and fuel consumption values can be constructed using data from actual driving conditions, A method is described for measuring the tailpipe emissions and fuel consumption of vehicles operating in realistic on-road conditions. The method, which focuses on the calibration of a chassis dynamometer for use in modeling on-road driving conditions, is demonstrated on a 1988 Chevrolet Corsica and the results are presented for this vehicle. The results support the conclusion that this method is suitable for measuring the emissions and fuel consumption of vehicles in on-road operation for the purposes of developing emission factors for atmospheric models.