Method and arrangement in a hybrid vehicle for maintaining a catalyst in an effective state

摘要

Method for maintaining a catalyst of an emissions system in a hybrid electric vehicle in an operative condition is disclosed. The method includes sensing that an engine of a hybrid electric vehicle has stopped operating. A time period is predicted after which a catalyst of an emissions system associated with the engine will cool to a light-off temperature below which the catalyst becomes ineffective. The predicting step is based on known qualities of the catalyst and ambient conditions in which the vehicle is being operated. The engine is restarted when the predicted time period has expired thereby maintaining the catalyst at temperatures in excess of the light-off temperature.