Reaction of the electrically-heated catalyst of a four-stroke motorcycle engine under cold-start conditions with additional enrichment of the intake mixture

摘要

By using additional fuel enrichment, the influence of an electrical heater and the oxidation of unburnt exhaust gases on the reaction of an electrically-heated catalyst under cold-start condition of a four-stroke motorcycle engine was investigated. The effects of different cold-start enriching times, heating temperatures, exhaust settings of the CO level and heating positions were studied. The heating temperatures were 60, 80, 100 and 120℃, and the CO levels were 1.0 and 1.8 per cent. The two heating positions were at the inlet and the mid-section of the catalyst. The results showed that additional enrichment of the intake mixture can reduce the heating temperature for self-reaction of the catalyst as well as improve the conversion efficiency of the catalyst on the exhaust emissions. High conversion efficiency has been achieved for a heating temperature as high as 100℃ for the 1.8%CO setting level. It has also been revealed that self-reaction of the catalyst was not possible for a heating temperature of up to 140℃ in the case of a 1.0%CO setting level.