Claims:We Claim:

1. A control unit (11) for detecting a leakage of fuel in a vehicle (10), said vehicle (10) comprising :
- a high pressure pump (14) connected between a fuel tank (12) and an engine (18);
- an oil tank (16) attached to said high pressure pump (14) and said engine (18);

characterized in that:
said control unit (11) adapted to:

- determine an amount of fuel consumed in said engine (18) for predefined distance, when said vehicle (10) is operating;
- detect a fuel level in said fuel tank (12) by a fuel level sensor (13), for every predefined time interval;
- compare determined amount of fuel consumed in said engine (18) and said fuel level in said fuel tank (12), with a predefined value;
- detect said leakage of said fuel from said high-pressure pump (14) into said oil tank (16), when said determined amount of fuel consumed in said engine (18) and said detected fuel level in said fuel tank (12), is less than said predefined value.
2. The control unit (10) as claimed in claim 1, wherein a fuel flow path (22) in said high pressure pump (14) is in fluid connection with an oil flow path (20) in said high pressure pump (14).
3. The control unit (10) as claimed in claim 1, wherein said fuel leaks into said fuel tank (12) from said high pressure pump (14), while flowing from said fuel tank (12) to said engine (18).
4. The control unit (10) as claimed in claim 1, wherein said control unit (10) adapted to detect a malfunctioning of a plunger-sealing ring (24) of said high-pressure pump (14) based on said detected fuel leakage.
5. A method for detecting a fuel leakage in a vehicle (10), said method comprising :
- determining an amount of fuel consumed in an engine for a predefined distance, when said vehicle (10) is operating;
- detecting a fuel level in a fuel tank by a fuel level sensor (13);
- comparing said amount of fuel consumed in said engine (18) and said fuel level in said fuel tank (12) with a predefined value;
- detecting said leakage of said fuel from a high-pressure pump (14) into an oil tank (16) of said vehicle (10), when said determined amount of fuel consumed in said engine (18) and said detected fuel level in said fuel tank (12) is less than said predefined value.
, 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 a control unit for detecting a leakage of fuel in a vehicle.
Background of the invention
[0002] A fuel injection system for supplying fuel to an engine by injection includes a high-pressure pump, which pressurizes the fuel to a high pressure and supplies the fuel to the engine through injection valves (injectors), and a low-pressure pump, which draws the fuel from a fuel tank and supplies the fuel to the high-pressure pump. One of the most important factors that contributes to the efficiency and durability of internal combustion engines is lubrication. As engine oil breaks down, it is less effective in protecting an engine from damage caused by friction between engine parts. More specifically, the normal life span of motor oils is limited by thermal breakdown, additive depletion and carbon particulates that result from the combustion process. For evaluating the performance of an internal combustion engine and the corresponding engine design development, it is desirable to provide dynamic measurements of fuel and engine oil consumption during operation of the internal combustion engine.
[0003]Prior art patent application US8643388 discloses a method for measuring fuel contamination in oil that uses a material in contact with oil whereby fuel intrusion into the oil will change the electrical, mechanical, and/or chemical properties of the material as compared to the same electrical, mechanical, and/or chemical properties of the material when in contact only with mineral or synthetic oil only.
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 control unit in a vehicle according to one embodiment of the invention;
[0006] FIG. 2 illustrates a flowchart of for detecting a fuel leakage in a vehicle.

Detailed description of the embodiments
[0007] FIG. 1 illustrates a control unit for detecting a leakage of fuel in a vehicle according to one embodiment of the invention. The vehicle comprises a high-pressure pump connected between a fuel tank and an engine and an oil tank attached to the high-pressure pump and the engine. The control unit adapted to determine an amount of fuel consumed in the engine for predefined distance, when the vehicle is operating, and to detect a fuel level in the fuel tank by a fuel level sensor, for every predefined time interval. The control unit adapted to compare determined amount of fuel consumed in the engine and the fuel level in the fuel tank, with a predefined value. The control unit adapted to detect the leakage of the fuel from said high-pressure pump into the oil tank, when the determined amount of fuel consumed in the engine and the detected fuel level in the fuel tank, is less than the predefined value.

[0008] Further the construction of the control unit 11 in the vehicle 10 is explained as follows. The fuel sensor 13 adapted to detect the fuel level in the fuel tank 12 is integrated in the control unit 11 according to one embodiment of the invention. According to another embodiment of the invention, the fuel level sensor 13 is placed in the fuel tank 12 and the control unit 11 receives the fuel level value, transmitted from the fuel level sensor 13. The fuel level sensor 13 detects the fuel level in the fuel tank for every predefined time interval, when the vehicle is operating. For instance, the fuel level sensor 13 senses the fuel level as “x1”, “x2” for every 30 minutes of time interval. The oil tank 16 is attached to the high-pressure pump 14. The oil in the oil tank 16 is used to lubricate the high-pressure pump 14 and the engine 18. The fuel flow path 20 present in the high-pressure pump 14 is in fluid connection with the oil flow path 22 of the oil tank 16, in the high-pressure pump 14. The fuel leaks into the oil tank 16 through this oil flow path 22, while flowing from the fuel tank 12 to the engine 18 via the high-pressure pump 14. The high pressure pump 14 further comprises a plunger sealing ring 24 positioned in between the oil tank 16 and the high pressure pump 14 in the oil flow path 22 as shown in the fig 1. The plunger-sealing ring 24 prevents the fuel entering the oil tank 16 while flowing to the engine 18 from the high-pressure pump 14. If the plunger-sealing ring 24 is broken or damaged, then an amount of fuel flowing to the engine 18, leaks into the oil tank 16 through this plunger-sealing ring 24 via the oil flow path 22. The control unit 11 is an engine control unit according to one embodiment of the invention. The control unit 11 is chosen from a group of control units comprising a microcontroller, a microprocessor, an integrated digital chip or the like.

[0009] Figure 2 illustrates a method of detecting a fuel leakage in the vehicle 10. In step S1, an amount of fuel consumed in an engine 18 for a predefined distance is determined, when the vehicle 10 is operating. In step S2, a fuel level sensor 13 detects a fuel level in a fuel tank 12. In step S3, the amount of fuel consumed in the engine 18 and the fuel level in the fuel tank 12 is compared with a predefined value. In step S4, the leakage of the fuel from a high-pressure pump 14 into an oil tank 16 of the vehicle 10 is detected, when the determined amount of fuel consumed in the engine 18 and the detected fuel level in the fuel tank 12 is less than the predefined value. According to one embodiment of the invention, the predefined value is a total amount of fuel in the fuel tank 12.

[0010] The method of detecting a fuel leakage in a vehicle 10 is explained with an example. The mileage (one liter of fuel consumed for certain number of kilometers) of the vehicle 10 is 20kmsperliter. When the vehicle 10 starts operating , after a predefined distance (say 100kms) , the fuel consumed in the engine 18 is 5.5 liters and the fuel level in the fuel tank 12 at that instant of time is 43 liters . The control unit 11 determines the fuel consumed in the engine 18 while the vehicle is operating as 5.5liters for 100kms and the fuel sensor 13 detects the fuel level in the fuel tank 12 as 43 liters. The control unit 11 adds both the above-disclosed values as 48.5 (liters). The control unit 11 compares the determined fuel value with a predefined value (i.e., 50 liters). If the determined fuel level is less than the predefine value (i.e., 48.5 <50), then the control unit 11 determines that the amount of fuel obtained from the difference between the determined fuel value and the predefined value, is leaked into the oil tank 16 from the high-pressure pump 14. I.e., 1.5 liters (50-48.5 = 1.5liters) is leaked into the oil tank 16 contaminating the lubrication oil, while flowing from the high-pressure pump 14 to the engine 18.

[0011] In addition to that, the fuel leakage detection helps in identifying a malfunctioning in a plunger seal ring 24 of the high pressure pump 14. If the plunger seal ring 24 is broken, the fuel leaks into the oil tank 16 from the high-pressure pump 14, thus the oil is contaminated in the oil tank 16. With the above method, the amount of fuel leaked into the oil is detected without any additional equipment, thus making it a cost-effective solution. The above-disclosed method provides a solution in detecting the oil contamination in the vehicle 10 in the real time.

[0012] 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 injector 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.