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KR-102962210-B1 - METHOD FOR DIAGNOSING FUEL LEAKAGE OF VEHICLE

KR102962210B1KR 102962210 B1KR102962210 B1KR 102962210B1KR-102962210-B1

Abstract

The present invention includes a pressure measurement step of measuring the pressure of a fuel tank through a pressure sensor when the fuel system is sealed upon ignition off; a temperature measurement step of measuring the internal temperature of the fuel tank through a temperature sensor; and a leak diagnosis step of performing a first leak diagnosis through a control unit when the pressure value of the fuel tank measured in the pressure measurement step is maintained at an atmospheric pressure level, and performing a second leak diagnosis and a third leak diagnosis through the control unit when the pressure value is maintained at a level higher than positive pressure or lower than negative pressure, thereby diagnosing different leakage conditions according to the pressure conditions of the fuel tank.

Inventors

  • 이정석
  • 송주태
  • 박대현

Assignees

  • 현대자동차주식회사
  • 기아 주식회사

Dates

Publication Date
20260507
Application Date
20210426

Claims (12)

  1. A pressure measurement step for measuring the pressure in the fuel tank through a pressure sensor when the engine is off and the fuel system is sealed; A temperature measurement step of measuring the internal temperature of the fuel tank using a temperature sensor; A leak diagnosis step for diagnosing different leakage conditions according to the pressure conditions of the fuel tank, wherein, as the pressure value of the fuel tank measured in the pressure measurement step is maintained at an atmospheric pressure level, a first leakage diagnosis is performed through a control unit, and as the pressure value is maintained at a level higher than positive pressure or lower than negative pressure, a second leakage diagnosis and a third leakage diagnosis are performed through the control unit; and A method for diagnosing fuel leakage in a vehicle, characterized by including: a final leakage determination step in which, if a suspected leak is diagnosed in the leak diagnosis step, the engine is switched to an ON state via the control unit, negative pressure is generated in the fuel tank, and while the negative pressure is maintained, a leak is selectively determined through a change in pressure value.
  2. In Article 1, The above leak diagnosis step is, A method for diagnosing fuel leakage in a vehicle, characterized by having a first comparison step in which, during the first leakage diagnosis, the fuel system is opened and then sealed again through the control unit, and as the first waiting time elapses, the amount of change in the pressure value through the control unit and the amount of change in the temperature value measured through the temperature measuring unit are compared with the pressure threshold value and the temperature threshold value, respectively.
  3. In Article 2, The above first comparison step is, A method for diagnosing fuel leakage in a vehicle, characterized by diagnosing that there is no leakage when the amount of change in the pressure value and the amount of change in the temperature value exceed the pressure threshold and the temperature threshold, respectively.
  4. In Article 2, The above first comparison step is, A method for diagnosing fuel leakage in a vehicle, characterized by comprising a second comparison step in which, if the amount of change in the pressure value and the amount of change in the temperature value are each less than or equal to the pressure threshold and the temperature threshold, respectively, after the second waiting time has elapsed, the pressure value relative to the temperature value is compared with the mapping value of a leakage judgment table through the control unit.
  5. In Article 4, The above second comparison step is, A method for diagnosing fuel leakage in a vehicle, characterized by diagnosing no leakage when the pressure value relative to the temperature value exceeds the mapping value, and diagnosing suspected leakage when the pressure value is less than or equal to the mapping value.
  6. In Article 1, The above leak diagnosis step is, A method for diagnosing fuel leakage in a vehicle, characterized by comprising a first temperature change amount comparison step in which, during the second leakage diagnosis above, if the pressure value remains above a static pressure after a waiting time has elapsed, the leakage is diagnosed as non-leakage, and if the pressure value is below a static pressure, the temperature change amount is compared through the control unit.
  7. In Article 6, The above first temperature change amount comparison step is, A method for diagnosing fuel leakage in a vehicle, characterized by diagnosing a suspected leak when the above pressure value is less than the static pressure and the amount of change in the above temperature value increases.
  8. In Article 6, The above first temperature change amount comparison step is, A method for diagnosing fuel leakage in a vehicle, characterized by performing the first leakage diagnosis when the above pressure value is less than the static pressure and the amount of change in the above temperature value decreases.
  9. In Article 1, The above leak diagnosis step is, A method for diagnosing fuel leakage in a vehicle, characterized by comprising a second temperature change amount comparison step in which, during the third leakage diagnosis above, after a waiting time has elapsed, if the pressure value is below negative pressure, it is diagnosed as having no leakage, and if the pressure value exceeds negative pressure, the amount of change in the temperature value is compared through the control unit.
  10. In Article 9, The above second temperature change amount comparison step is, A method for diagnosing fuel leakage in a vehicle, characterized by diagnosing a suspected leak when the above pressure value exceeds negative pressure and the amount of change in the above temperature value decreases.
  11. In Article 9, The above second temperature change amount comparison step is, A method for diagnosing fuel leakage in a vehicle, characterized by performing the first leakage diagnosis when the above pressure value exceeds negative pressure and the amount of change in the above temperature value increases.
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Description

Method for Diagnosing Fuel Leakage of Vehicle The present invention relates to a method for diagnosing fuel leakage in a vehicle, and more specifically, to a method for diagnosing fuel leakage in a vehicle in which different leakage diagnoses are performed according to the pressure conditions of the fuel tank when the engine is off after driving, and when performing the leakage diagnosis accordingly, negative pressure is applied to the fuel system during the idle section while driving or stopped, and the presence or absence of leakage is finally determined through pressure behavior. Generally, a hybrid vehicle refers to an electric vehicle that efficiently combines two or more different types of power sources and drives using the power of one of them depending on the driving conditions of the vehicle. In addition, the above-mentioned hybrid vehicle generally adopts a method in which the vehicle is driven by the drive motor using the power of the battery until it starts and reaches a certain speed, is driven by the power of the engine during constant speed driving, and is driven by using both the power of the engine and the battery when accelerating to maximum speed. Accordingly, by minimizing the use of fossil fuels such as gasoline or diesel, it is very helpful for improving fuel efficiency and, as a result, reducing air pollution by minimizing exhaust gas emissions, active research is currently being conducted, and it is already being mass-produced and sold in developed countries. Even in the case of such hybrid vehicles, depending on the degree of volatility of the fuel stored in the fuel tank, evaporative gases are emitted as time passes, and if these evaporative gases are emitted into the outside air, not only is fuel wasted, but pollution may also occur due to the emission of unburned gases. Accordingly, a hybrid vehicle is equipped with an evaporative emission control system that supplies evaporative emissions generated from a fuel tank to an engine, and such an evaporative emission control system includes a fuel tank that stores fuel for the vehicle, an evaporative emission collector connected to the fuel tank via a pipeline to collect evaporative emissions generated from the fuel tank, and a supply pipeline that supplies the evaporative emissions from the evaporative emission collector to the vehicle's engine. However, since pollution caused by evaporative emissions cannot be prevented if leakage occurs in such evaporative emission control systems, automobile manufacturers are devising methods to detect leakage in the said evaporative emission control systems. FIG. 1 is a diagram schematically illustrating a method for diagnosing fuel leakage of a vehicle according to an embodiment of the present invention. FIG. 2 is a drawing for showing a fuel system for a fuel leak diagnosis method of a vehicle according to an embodiment of the present invention. FIG. 3 is a drawing for sequentially showing a method for diagnosing fuel leakage of a vehicle according to an embodiment of the present invention. FIG. 4 is a diagram showing the diagnostic result of the first comparison step for a fuel leak diagnosis method of a vehicle according to an embodiment of the present invention. FIG. 5 is a diagram showing the diagnosis result of the second comparison step for the fuel leak diagnosis method of a vehicle according to an embodiment of the present invention. FIG. 6 is a diagram showing the mapping values of a leak judgment table for a fuel leak diagnosis method of a vehicle according to an embodiment of the present invention. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the attached drawings. The advantages and features of the present invention and the method for achieving them will become clear by referring to the embodiments described in detail below together with the accompanying drawings. However, the present invention is not limited by the embodiments disclosed below but may be implemented in various different forms, and these embodiments are provided merely to make the disclosure of the present invention complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. In addition, in describing the present invention, if it is determined that related known technologies, etc., may obscure the essence of the present invention, a detailed explanation thereof will be omitted. FIG. 1 is a diagram schematically illustrating a method for diagnosing a fuel leak in a vehicle according to an embodiment of the present invention, FIG. 2 is a diagram illustrating a fuel system for a method for diagnosing a fuel leak in a vehicle according to an embodiment of the present invention, and FIG. 3 is a diagram sequentially illustrating a method for diagnosing a fuel leak in a vehicle according to an embodiment of the present invention. And, FIG. 4 is a diagram showin