Cold-start hydrocarbon emissions in port-injected gasoline engines

An analysis is made of the sources of the high engine-out hydrocarbon (HC) emissions during cold starting of port-injected gasoline engines. A cycle-b y-cycle analysis of the different parameters, which affect engine-out HC em issions, is made during the startup process. The contribution of each cylin der of a four-stroke V6, 3.3 1 production engine in the total HC emissions is investigated, The HC emissions were measured in the exhaust port using a fast response flame ionization detector (FID), The effect of the initial s tartup position of the piston and valves in the cycle on combustion and HC emissions is examined. The mass of fuel injected, burned and emitted was ca lculated for each of the first 120 cycles. Different approaches to reduce e ngine-out and tailpipe HC emissions during cold-start are discussed. (C) 19 99 Elsevier Science Ltd. All rights reserved.