Eric Krengel

Method and system to mitigate pump noise in a direct injection, spark ignition engine

A method and system for controlling a fuel pressurizing system in a direct-injection, spark-ignition engine is disclosed such that the ticking sound of a solenoid valve in the high pressure pump is disabled at certain engine operating conditions. The fuel pressurizing system includes two pumps in series: a low pressure lift pump and a high pressure pump. Based on an engine operating parameter (speed, load, temperature, fuel delivery rate, as examples) the high pressure fuel pump is disabled when the engine operating parameter is below a threshold. The disablement of the pump is accomplished by turning off the normally-open solenoid valve on the inlet side of the high pressure pump, particularly at low speed and/or low torque conditions, e.g., idle, when the ticking of the injector is particularly noticeable. When the pump is disabled, fuel is supplied to the fuel injectors at lift pump pressure.