Strategy for fueling a diesel engine

摘要

A compression ignition engine (10) operates to fuel an engine cylinder (12) to create an in-cylinder air-fuel charge and to cause that charge to autoignite. A fuel injector (20) operates to inject fuel into the engine cylinder for substantially the entire duration of a first phase (24) of fuel injection at substantially the maximum injection pressure that the fuel injector can deliver to create a premixed fraction of the in-cylinder air-fuel charge prior to autoignition. As the first phase ends, fuel injection transitions to a second phase (26) which commences in advance of autoignition. During the second phase, the fuel injector injects fuel into the engine cylinder at a rate of injection that is significantly less than the rate of injection used during the first phase.

主权项

1. A method of operating a compression ignition engine by fueling an engine cylinder to create an in-cylinder air-fuel charge and to cause that charge to autoignite, the method comprising:
operating a fuel injector to inject fuel into the engine cylinder for the entire duration of a first phase of fuel injection at a maximum injection pressure that the fuel injector can deliver to create a premixed fraction of the in-cylinder air-fuel charge prior to autoignition, with the duration of the first phase of fuel injection being based at least in part on a speed and a load of the engine; operating the fuel injector to inject a second phase of the same fuel into the engine cylinder at an injection pressure less than the maximum injection pressure that the fuel injector can deliver, with the second phase of fuel being injected in advance of autoignition of the first phase of fuel and the injection pressure of the second phase of fuel injection being based at least in part on the speed and load of the engine.