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 a fuel injection system, and more specifically to a method to detect filter clogging in a low pressure fuel inlet system of an internal combustion engine.

Background of the invention
[0002] US 2010002342 AA describes a stand-alone pump shut-off controller. Embodiments of the invention provide a stand-alone controller and a method for controlling a pump motor driven by an alternating current source. The stand-alone controller includes a power terminal for connection with the alternating current source and a load terminal for connection with the pump motor. The stand-alone controller further includes an enable switch to form a power line carrying power from the alternating current source to the pump motor. The stand-alone controller can store a first current being drawn through the power line by the pump motor when a control switch is actuated. A state of the enable switch is based on a comparison of the first current to a second current being drawn through the power line by the pump motor.

Brief description of the accompanying drawing
[0003] Figure 1 illustrates a flowchart depicting a method to detect filter clogging in a low pressure inlet system of the fuel injection system in one embodiment of the invention.

Detailed description of the embodiments
[0004] Figure 1 illustrates a method 100 to detect clogging of a fuel filter in a low pressure fuel inlet system of a low pressure fuel pump by an engine control unit. The method 100 comprises determining 110 by the engine control unit if speed of an engine is zero, determining by the engine control unit if a battery is turned on, holding 130 a time period of t1 seconds by the engine control unit from a time when the engine is switched on, and capturing 140 a current flowing through the low pressure fuel pump for a time period of t2 seconds by the engine control unit after holding the time period of t1 seconds. The method further comprises capturing 150 a voltage across the low pressure fuel pump for the time period of t2 seconds by the engine control unit after holding the time period of t1 seconds, calculating 160 an area under a current curve by means of the captured value of current flowing through the low pressure fuel pump for a time period of t2 seconds by the engine control unit, identifying 170 a pump current curve corresponding to the captured voltage across the low pressure fuel pump to identify a area of the reference pump current curve, determining 180 whether the area under a current curve by means of the captured value of current flowing through the low pressure fuel pump for the time period of t2 seconds by the engine control unit is greater than the area of the reference pump current curve, indicating 190 that the fuel filter in the low pressure fuel inlet system is clogged and if the area under the current curve by means of the captured value of current flowing through the low pressure fuel pump for a time period of t2 seconds by the engine control unit is greater than the area of the reference pump current curve, and indicating 200 that the fuel filter in the low pressure fuel inlet system is not clogged if the area under a current curve by means of the captured value of current flowing through the low pressure fuel pump for a time period of t2 seconds by the engine control unit is lesser than the area of the reference pump current curve.

[0005] Figure 1 illustrates a flowchart depicting a method 100 to detect filter clogging in a low pressure inlet system of the fuel injection system in one embodiment of the invention. The method 100 comprises determining 110 by an engine control unit if a speed of an engine is zero. If the diagnostic check by the engine control unit is that the speed of the engine is zero, the engine control unit determines 120 if a battery is switched on or off, and holding 130 a time period of t1 seconds by the engine control unit from a time when the engine is switched on. The holding period of t1 seconds by the engine control unit from a time when the engine is switched on allows the engine control unit to allow sufficient time for the suction load acting on the engine to be accounted for. The method further comprises capturing 140 a current flowing through the low pressure fuel pump for a time period of t2 seconds by the engine control unit after holding the time period of t1 seconds. More specifically, after the holding period of t1 seconds by the engine control unit which accounts for the suction load acting on the engine, the time period of t2 seconds by the engine control unit allows for the pumping load acting on the engine to be accounted for. Therefore, the load acting on the low pressure inlet fuel system due to the pumping action of the low pressure fuel pump is measured after the holding period of t1 seconds by the engine control unit which accounts for the pumping load acting on the low pressure inlet fuel system.

[0006] The method further comprises capturing 150 a potential difference across the low pressure fuel pump for a time period of t2 seconds by the engine control unit after holding the time period of t1 seconds. More specifically, after the holding period of t1 seconds by the engine control unit which accounts for the suction load acting on the engine, the time period of t2 seconds by the engine control unit allows for the pumping load acting on the engine to be accounted for. Therefore, the load acting on the low pressure fuel inlet system due to the pumping action of the low pressure fuel pump is measured after the holding period of t1 seconds by the engine control unit which accounts for the suction load acting on the engine.

[0007] After capturing 140 the current flowing through the low pressure fuel pump for a time period of t2 seconds by the engine control unit after holding the time period of t1 seconds, and capturing 150 the potential difference across the low pressure fuel pump for the time period of t2 seconds by the engine control unit after holding the time period of t1 seconds, an area under the current curve is calculated 160 by means of the captured 140 value of current flowing through the low pressure fuel pump for a time period of t2 seconds by the engine control unit. Thereafter, a pump current curve corresponding to the captured battery voltage is identified. By identifying the pump current curve corresponding to the captured battery voltage, a area of the reference pump current curve is identified 170. Thereafter, the engine control unit determines 180 whether the area under the current curve by means of the captured value of current flowing through the low pressure fuel pump for a time period of t2 seconds by the engine control unit is greater than the area of the reference pump current curve. If the area under the current curve by means of the captured value of current flowing through the low pressure fuel pump for a time period of t2 seconds by the engine control unit is greater than the area of the reference pump current curve, it is indicative 190 that the low pressure fuel inlet system is clogged. Conversely, if the area under the current curve by means of the captured value of current flowing through the low pressure fuel pump for a time period of t2 seconds by the engine control unit is lesser than the area of the reference pump current curve, it is indicative that the low pressure fuel inlet system is not clogged.

[0008] It must be understood that the embodiments explained above are only illustrative and do not limit the scope of the disclosure. Many modifications in the embodiments with regard to dimensions of various components are envisaged and form a part of this invention. The scope of the invention is only limited by the scope of the claims.
, Claims:CLAIMS

We Claim

1. A method (100) to detect clogging in a low pressure fuel inlet system of an internal combustion engine by an engine control unit, the method (100) comprising:
determining (110) by the engine control unit if a speed of an engine is zero;
determining (120) by the engine control unit if a battery is turned on;
holding (130) a time period of t1 seconds by the engine control unit from a time when the engine is switched on;
capturing (140) a current flowing through the low pressure fuel pump for a time period of t2 seconds by the engine control unit after holding the time period of t1 seconds;
capturing (150) battery voltage for the time period of t2 seconds by the engine control unit after holding the time period of t1 seconds;
calculating (160) an area under a current curve by means of the captured value of current flowing through the low pressure fuel pump for a time period of t2 seconds by the engine control unit;
identifying (170) a pump current curve corresponding to the captured battery voltage to identify an area of the reference pump current curve;
determining (180) whether the area under a current curve by means of the captured value of current flowing through the low pressure fuel pump for a time period of t2 seconds by the engine control unit is greater than the area of the reference pump current curve;
indicating (190) that low pressure fuel inlet system is clogged if the area under the current curve by means of the captured value of current flowing through the low pressure fuel pump for the time period of t2 seconds by the engine control unit is greater than the area of the reference pump current curve; and
indicating (200) that the low pressure fuel inlet system is not clogged if the area under a current curve by means of the captured value of current flowing through the low pressure fuel pump for a time period of t2 seconds by the engine control unit is lesser than the area of the reference pump current curve.