Search Results

In order to reduce tail-pipe hydrocarbon emissions from SI gasoline engines, rapid catalyst warm-up and improvement of catalyst conversion efficiency are important. There are many reports which have been published by manufacturers and research institutes on this issue. For further reduction of tail-pipe hydrocarbon emissions, it is necessary to reduce engine-out hydrocarbon emissions and to improve after treatment, during the time the catalyst is not activated. This paper quantitatively analyzed the fuel amount of intake port and cylinder wall-wetting, burned fuel and engine-out hydrocarbon emissions, cycle by cycle in firing condition, utilizing a specially designed analytical engine. The effect of mixture preparation and fuel properties for engine-out hydrocarbon emissions, during the cold engine start and warm-up period, were quantitatively clarified.