Fuel pump control with control mode switching between before and after engine starting

Abstract

In a fuel pump control, until a rotational speed of an electrically-driven fuel pump rises to a predetermined speed, an electric current supplied to the fuel pump at an engine starting is increased higher than that normally supplied after engine starting thereby causing fast build-up of the fuel pressure. After the fuel pump reaches the predetermined speed, the electric current is decreased to a normal after-start current thereby suppressing a fuel pressure overshoot and resulting overrich mixture. Alternatively, a fuel pump speed is raised by the voltage control first at an engine starting operation, while switching the voltage control to the current control intermittently to detect the voltage applied to the fuel pump. When the detected voltage reaches a first predetermined voltage, the fuel pump speed is controlled exclusively by the current control.

Dependencies are inferred from the claim text.