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 clogging in a low pressure fuel inlet system of an internal combustion engine.

Background of the invention
[0002] IN 202241035707 describes a method to detect clogging in a low pressure fuel inlet system of a of a fuel injection system by an engine control unit. The method comprises determining by the engine control unit if a speed of an engine is zero, determining by the engine control unit if a battery is turned on, holding a time period of t1 seconds by the engine control unit from a time when the engine is switched on, and capturing 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 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 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, and identifying a pump current curve corresponding to the captured voltage across the low pressure fuel pump to identify an area of the reference pump current curve. Further, the method comprises determining 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 that 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 that the fuel filter in the low pressure fuel inlet system is not clogged.
Brief description of the accompanying drawing
[0003] Figure 1 illustrates a flowchart depicting a method to detect 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 in a low pressure fuel inlet system of an internal combustion engine by an engine control unit. The method 100 comprises 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, and capturing 140 a voltage across a battery 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 initial battery voltage at the start of 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 voltage curve by means of the captured value of voltage across the battery for the time period of t2 seconds by the engine control unit, identifying 170 battery voltage curve specific to a start of captured battery voltage to identify a reference area, determining 180 whether the area under the voltage curve by means of the captured value of voltage across the battery for the time period of t2 seconds by the engine control unit is lesser than an area of a reference pump voltage curve, indicating 190 that the low pressure fuel inlet system is clogged if the area under the voltage curve by means of the captured value of voltage across the battery for the time period of t2 seconds by the engine control unit is greater than the area of the reference pump voltage curve, and indicating 200 that the low pressure fuel inlet system is not clogged.

[0005] Figure 1 illustrates a flowchart depicting a method 100 to detect 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 voltage across the battery 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] After capturing 140 the battery voltage for a time period of t2 seconds by the engine control unit after holding the time period of t1 seconds, and capturing 150 the initial battery voltage at the start of 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 battery voltage for a time period of t2 seconds by the engine control unit. Thereafter, a battery voltage curve corresponding to the captured initial battery voltage is identified. By identifying the battery voltage curve corresponding to the captured initial battery voltage, an area of the reference battery voltage curve is identified 170. Thereafter, the engine control unit determines 180 whether the area under the voltage curve by means of the captured value of battery voltage for a time period of t2 seconds by the engine control unit is lesser than the area of the reference battery voltage curve. If the area under the voltage curve by means of the captured value of battery voltage for a time period of t2 seconds by the engine control unit is lesser than the area of the reference pump voltage curve, it is indicative 190 that the low pressure fuel inlet system is clogged. Conversely, if the area under the voltage curve by means of the captured value of battery voltage for a time period of t2 seconds by the engine control unit is greater than the area of the reference pump voltage curve, it is indicative that the low pressure fuel inlet system is not clogged.

[0007] 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:
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 voltage across a battery for a time period of t2 seconds by the engine control unit after holding the time period of t1 seconds;
capturing (150) the initial battery voltage at the start of time period t2 seconds by the engine control unit after holding the time period of t1 seconds;
calculating (160) an area under a voltage curve by means of the captured value of voltage across the battery for the time period of t2 seconds by the engine control unit;
identifying (170) battery voltage curve specific to captured initial battery voltage to identify a reference area;
determining (180) whether the area under the voltage curve by means of the captured value of voltage across the battery for the time period of t2 seconds by the engine control unit is lesser than an area of a reference pump voltage curve;
indicating (190) that low pressure fuel inlet system is clogged if the area under the voltage curve by means of the captured value of voltage across the battery for the time period of t2 seconds by the engine control unit is greater than the area of the reference battery voltage curve; and
indicating (200) that the low pressure fuel inlet system is not clogged.