Patent ID: 7412968
Filing Date: 2008-08-19
Classification: F02D,F02M

Abstract:
1. A fuel supply apparatus for an engine, comprising: a fuel injection valve capable of injecting fuel to the engine; a fuel tank capable of storing the fuel for the engine; a fuel pump capable of supplying the fuel in the fuel tank to the fuel injection valve via a fuel pipe; a mechanical relief valve capable of returning the fuel in the fuel pipe into the fuel tank when a pressure in the fuel pipe exceeds a threshold; a pressure sensor capable of detecting a pressure of the fuel in the fuel pipe; and a control unit configured to input thereto a signal detected from the pressure sensor to output therefrom a manipulated variable for the fuel pump, wherein the control unit is configured to determines whether the pressure sensor is in a normal operation state or in an abnormal operation state; wherein when the pressure sensor is determined to be in the normal operation state, the control unit calculates the manipulated variable so that the fuel pressure detected by the pressure sensor approaches a target pressure; and wherein when the pressure sensor is determined to be in the abnormal operation state, the control unit is configured to fixedly maintain the manipulated variable at a manipulated variable at which a discharge amount of the fuel pump reaches a maximum amount, to thereby hold the fuel pressure in the fuel pipe in the vicinity of a valve-opening pressure of the relief valve.