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This paper describes the findings of a laboratory effort to demonstrate improved automotive exhaust emission control with a cold-start hydrocarbon collection system. The emission control strategy developed in this study incorporated a zeolite molecular sieve in the exhaust system to collect cold-start hydrocarbons for subsequent release to an active catalytic converter. A prototype emission control system was designed and tested on a gasoline-fueled vehicle. Continuous raw exhaust emission measurements upstream and downstream of the zeolite molecular sieve revealed collection, storage, and release of cold-start hydrocarbons. Federal Test Procedure (FTP) emission results show a 35 percent reduction in hydrocarbons emitted during the cold-transient segment (Bag 1) due to adsorption by the zeolite.

This paper describes the effort to characterize regulated and unregulated exhaust emissions from four gasoline powered passenger cars equipped with three-way catalyst control systems. The vehicles have been evaluated over four test cycles, with three fuels at four mileage accumulation points. In addition to the currently regulated automobile emissions, exhaust emission components measured include: sulfate, aldehydes, ammonia, sulfur dioxide, cyanide, and several other compounds. From the standpoint of toxicity, the most significant emissions from three-way catalyst systems are the currently regulated emissions, followed to a lesser degree by the sulfate emissions.