Purging a particulate trap of a diesel engine

摘要

The invention relates to a method of injecting fuel into the cylinders of a diesel engine having a particulate trap. The injection of fuel into each cylinder during each combustion cycle is divided in a plurality of discreet events together forming an injection state. To purge the particulate trap, the injection state is switched in a sequence between a first injection state that produces exhaust gases having a high temperature and a second injection state that produces exhaust gases with a high hydrocarbon content at a lower temperature The switching frequency is sufficiently high for the exhaust gases produced during combustion events with differing injection states to mix with one another in the exhaust system upstream of the particulate trap. The excess hydrocarbons combust to burn off the particles in the trap. Additionally different cylinders are sequentially selected to operate with a different injection state.