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US 7,412,968 B2Granted
Fuel supply apparatus for engine and control method of same apparatus
AssigneeHitachi, Ltd.
InventorsKeiichi Takayanagi, Junichi Furuya
Life of this patent
Estimating the term…
Abstract
In a fuel supply apparatus for an engine, which is provided with a relief valve for returning fuel in a fuel pipe into a fuel tank when a fuel pressure exceeds a threshold, and also feedback controls a discharge amount of a fuel pump so that the fuel pressure detected by a pressure sensor approaches a target pressure, when the pressure sensor is failed, a duty of a PWM signal for the fuel pump is fixedly maintained at a predetermined value, and fuel injection pulse width is calculated on the assumption that the fuel pressure is held at the threshold.
Claims16
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.
8 more elements
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 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 determine whether the pressure sensor is in a normal operation state or in an abnormal operation state;
- wherein when the pressure is determined to be in the normal operation state, the control unit is configured to calculate the manipulated variable so that the fuel pressure detected by the pressure sensor approaches a target pressure;
- 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 reference manipulated variable corresponding to a reference fuel pressure;
- and
- wherein when the manipulated variable is fixedly maintained at the reference manipulated variable, an operation of the engine under a condition that a fuel supply amount to the engine is insufficient is restricted.
9 more elements
A fuel supply apparatus for an engine, comprising:
- fuel injecting means for injecting fuel to the engine;
- fuel reserving means for reserving the fuel for the engine;
- fuel supplying means for supplying the fuel in the fuel reserving means to the fuel injecting means via a fuel pipe;
- mechanical relieving means for returning the fuel in the fuel pipe into the fuel reserving means when a pressure in the fuel pipe exceeds a threshold;
- pressure detecting means for detecting a pressure of the fuel in the fuel pipe;
- and
- control means for inputting thereto a signal detected from the pressure detecting means to output a manipulated variable for the fuel supply means,
- wherein the control means is configured to determine whether the pressure detecting means is in a normal state or in an abnormal state;
- wherein when the pressure detecting means is in the normal state, the control means is configured to calculate the manipulated variable so that the fuel pressure detected by the pressure detecting means approaches a target pressure;
- and
- wherein when the pressure detecting means is in the abnormal state, the control means 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 a fuel pressure in the fuel pipe in the vicinity of a valve-opening pressure of the relief valve.
8 more elements
A control method of a fuel supply apparatus for an engine, which is provided with a fuel pump capable of supplying fuel in a fuel tank to a 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;
- and a pressure sensor capable of detecting a pressure of the fuel in the fuel pipe, comprising the steps of:
- determining whether the pressure sensor is in the normal operation state or in an abnormal operation state;
- calculating, when the pressure sensor is in the normal operation state, a manipulated variable so that the fuel pressure detected by the pressure sensor approaches a target pressure;
- and
- fixedly maintaining, when the pressure sensor is determined to be in the abnormal operation state, the manipulated variable at a manipulated variable at which a discharge amount of the fuel pump reaches a maximum amount so that the fuel pressure in the fuel pipe is held in the vicinity of a valve-opening pressure of the relief valve, thereby outputting the maintained manipulated variable to the fuel pump.
3 more elements
A control method of a fuel supply apparatus for an engine, which is provided with a fuel pump capable of supplying fuel in a fuel tank to a fuel injection valve via fuel pipe;
- a relief valve capable of returning the fuel in the fuel pipe in to the fuel tank when a pressure in the fuel pipe exceeds a threshold;
- and a pressure sensor capable of detecting a pressure of the fuel in the fuel pipe, comprising the steps of:
- determining whether the pressure sensor is in a normal operation state or in an abnormal operation state;
- calculating, when the pressure sensor is in the normal operation state, a manipulated variable so that the fuel pressure detected by the pressure sensor approaches a target pressure;
- fixedly maintaining, when the pressure sensor is in the abnormal operation state, a manipulated variable at a reference manipulated variable that corresponds to a reference fuel pressure set before hand;
- outputting the maintained manipulated variable to the fuel pump;
- and
- restricting an operation of the engine under a condition that a fuel supply amount to the engine is insufficient, when the manipulated variable is fixedly maintained at the reference manipulated variable that corresponds to the reference fuel pressure.
5 more elements
A fuel supply apparatus for an engine, comprising:
- fuel injecting means for injecting fuel to the engine;
- fuel reserving means for reserving the fuel for the engine;
- fuel supplying means for supplying the fuel in the fuel reserving means to the fuel injecting means via a fuel pipe;
- relieving means for returning the fuel in the fuel pipe into the fuel reserving means when a pressure in the fuel pipe exceeds a threshold;
- pressure detecting means for detecting a pressure of the fuel in the fuel pipe;
- and
- control means for inputting thereto a signal detected from the pressure detecting means to output a manipulated variable for the fuel supply means,
- wherein the control means is configured to determine whether the pressure detecting means is in a normal state or in an abnormal state;
- wherein when the pressure detecting means is in the normal state, the control means is configured to calculate the manipulated variable so that the fuel pressure detected by the pressure detecting means approaches a target pressure;
- wherein when the pressure detecting means is in the abnormal state, the control means is configured to fixedly maintain the manipulated variable at a reference manipulated variable that corresponds to a reference fuel pressure;
- and
- wherein when the manipulated variable is fixedly maintained at the reference manipulated variable, an operation of the engine under a condition that a fuel supply amount to the engine is insufficient is restricted.
9 more elements
Dependencies are inferred from the claim text.