Lift pump control in engine fuel system with injection

摘要

An economical method for controlling a lift pump 72 operating as part of a direct injection fuel system is described in which at least two distinct operating modes are provided for the lift pump 72. In a fuel delivery mode where an injection pump 74 is activated, the current commands used to achieve a particular lift pump outlet pressure while the injection pump 74 was off can be retrieved from memory and output so that a particular pressure is achieved. This allows the lift pump pressure to be controlled without a pressure transducer located at the lift pump outlet.