Claims:We Claim:
1. A method of detecting failure in a metering unit of a fuel injection pump, said metering unit located upstream to said fuel injection pump, said method comprising:
receiving (100), by a processor a magnitude of current supplied to said metering unit.

measuring (102), by said processor quantity of fuel supplied to said fuel injection pump;

comparing (104), by said processor said current with said quantity of fuel for determining a deviation of said metering unit from a data map;

measuring (106), by said processor a frequency of said deviation during working of said metering unit; and

alerting (108),by said processor if said frequency exceeds a threshold limit defined for said metering unit.

2. The method of claim 1, wherein said processor is an electronic control unit.

3. The method of claim 1, wherein said alert is via a indication on dashboard of the vehicle.
, Description:Complete Specification:

The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.
Field of the invention
[0001]This invention relates to the field of metering unit in a fuel injection pump.

Background of the invention
[0002]A metering unit is used for controlling the quantity of fuel delivered to the fuel injection pump. A metering unit drifts if for a current supplied the metering unit delivers more quantity of fuel than what is required into the fuel injection pump. This is called drifting of metering unit. Every time a metering unit drifts, the control unit influences the governor so as to cause the metering unit to work within the calibrated range of working. However, if the frequency of drifting of metering unit increases, then it leads to failure of metering unit. Hence there is a need to detect condition of metering unit before failure for preventive and corrective actions.

[0003]Prior art patent application IN03614CH2012A proposes a method to detect a malfunction in a fuel supply System. The fuel supply system comprises a fuel tank to store fuel; a feed pump to draw fuel from the fuel tank; a filter to receive the fuel from the feed pump and filtering the fuel passing through the said fuel filter; a metering unit receiving fuel from the filter and supplying fuel to a high pressure pump; a high pressure pump receiving fuel from the filter and delivering the fuel at high pressure to a fuel accumulator; an engine control unit (ECU). The engine control unit is characterized by a means to diagnose the fuel supply system by comparing a change in fuel pressure to an expected change in fuel pressure for a given current drawn by the metering unit (20).

Brief description of the accompanying drawing
[0004] Different modes of the invention are disclosed in detail in the description and illustrated in the accompanying drawing:

[0005] FIG. 1 illustrates a method of detecting failure in a metering unit of a fuel injection pump.

Detailed description of the embodiments
[0006] FIG. 1 illustrates a method of detecting failure in a metering unit of a fuel injection pump. The metering unit is located upstream to the fuel injection pump and is used to control quantity of fuel that is delivered to the fuel injection pump. The method comprises receiving 100, by a processor a magnitude of current supplied to the metering unit. The processor measures 102 the quantity of fuel supplied to the fuel injection pump. The processor compares 104 the current with the quantity of fuel for determining a deviation of the metering unit, from a data map. The frequency of deviation is measured 106 by the processor during working of the metering unit. The processor alerts 108 if the frequency exceeds a threshold defined for the metering unit.

[0007]The above mentioned method focuses on the predicting the failure of a metering unit using a set of conditions. The disclosed method makes use of the quantity deviation values stored in a data map and compares them against the defined threshold limit curves. These thresholds are defined as a percentage allowed over and above the minimum and maximum limits defined in data map. The method also monitors the frequency of deviation during working of metering unit.

[0008]The working of the above mentioned method will be explained in further detail. The metering unit is located upstream to the fuel injection pump. Fuel from a fuel tank flows into the metering unit. The method comprises receiving 100 by a processor a magnitude of current supplied to the metering unit. The processor measures 102 the quantity of fuel supplied to the fuel injection pump. The processor compares 104 with current with quantity of fuel for determining a deviation of the metering unit from a data map. The processor measures 106 the frequency of the deviation during working of the metering unit, that is the processor keeps a tab on the number of times the metering unit has drifted. The processor alerts 108 if the frequency exceeds a threshold limit defined for the metering unit.

[0009]It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention in terms of the type of metering unit used. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.