KR20100059018A - Method for diagnosing leakage of fuel tank of hybrid vehicle - Google Patents

Abstract

A fuel leak diagnosis method of a hybrid vehicle for diagnosing a leak of a fuel tank is disclosed. The present invention, a) receives a plurality of information supplied from the outside to determine whether the driving stability condition is satisfied when the fuel leakage diagnosis condition is satisfied while driving, and as a result of determining the predetermined predetermined time when the driving stability condition is satisfied Determining whether it has passed; b) closing the fuel tank under control of the canister shutoff valve and the canister purge valve when the predetermined time has elapsed; c) measuring fuel evaporation after closing the fuel tank and then controlling the opening of the canister purge valve to lower the fuel pressure in the fuel tank; d) calculating a fuel leakage amount and a fuel tank leakage magnitude calculated as the fuel pressure increase amount in the fuel tank by closing the canister purge valve when the fuel pressure in the fuel tank reaches a predetermined target value; And e) determining whether the driving stability condition is satisfied on the basis of a plurality of pieces of information during the execution of step d), and if the driving stability condition is not satisfied, stopping the fuel leakage diagnosis and increasing the number of times of canceling the diagnosis. And terminating the program when the number of times of canceling the diagnosis is greater than or equal to a predetermined set value.

Description

How to diagnose fuel leakage in hybrid vehicles {METHOD FOR DIAGNOSING LEAKAGE OF FUEL TANK OF HYBRID VEHICLE}

The present invention relates to a hybrid vehicle fuel leakage diagnosis method, and more particularly, to a method for stopping fuel leakage diagnosis when the fuel leakage condition is not satisfied based on information supplied from the outside.

In general, the hybrid vehicle refers to an electric vehicle that is driven by using either power according to the driving state of the vehicle by efficiently combining two or more different power sources.

In addition, such a hybrid vehicle is usually driven by a drive motor using the power of a battery until the vehicle starts to reach a certain speed, and is driven by the power of the engine when driving at a constant speed, and the engine and the battery when accelerated at the maximum speed. It adopts the method of driving using the power of.

Accordingly, by minimizing the use of fossil fuels such as gasoline or diesel, it is very helpful to improve fuel efficiency, and thus, it is possible to reduce the air pollution by minimizing the emission of exhaust gas. Recently, active researches have been made in developed countries as well. It is already mass produced and sold.

Even in the case of such a hybrid vehicle, the amount of fuel stored in the fuel tank will vary depending on the degree of volatility of the fuel, but as time passes, the evaporation gas is discharged by evaporation. In addition, pollution may occur due to the release of unburned gases.

Therefore, the hybrid vehicle has an evaporative gas control system for supplying the engine with the evaporated gas generated from the fuel tank, the evaporative gas control system is connected to the fuel tank, the fuel tank for storing the fuel of the vehicle, the fuel tank is connected to the fuel And an evaporation gas collector for collecting the evaporated gas generated in the tank, and a supply line for supplying the evaporated gas of the evaporative gas collector to the engine of the vehicle.

However, when leakage occurs in such an evaporative gas control system, pollution by the evaporated gas cannot be prevented, and thus, an automobile manufacturer has devised a method of detecting leakage of the evaporative gas control system.

For example, in the case of a typical hybrid vehicle, the engine is stopped to improve fuel efficiency and exhaust gas while stopping, and when the engine is stopped, the fuel gas in the canister collecting the evaporative gas of the fuel tank cannot be burned. The fuel tank leak diagnosis could not be carried out during shutdown. In this case, the fuel tank leakage diagnosis was performed by using the cooling effect when the fuel leakage was performed while driving or when the vehicle was parked for a long time. Therefore, logic was needed to carry out a leak diagnosis of the fuel tank while driving the hybrid vehicle.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems as described above, and when the fuel leakage diagnosis condition is satisfied while driving the hybrid vehicle, the fuel leakage diagnosis is performed using the canister purge valve and the canister shutoff valve, and the purge valve. If the fuel leakage diagnosis condition is not satisfied during the fuel leakage diagnosis, the fuel leakage diagnosis is stopped to prevent the emission of harmful gases due to the leakage of the evaporative gas in the fuel tank by preventing the fuel leakage diagnosis even while the hybrid vehicle is running. The present invention aims to provide a method for diagnosing fuel leakage of a hybrid vehicle.

Technical means according to the present invention for achieving this object,

In the fuel leakage diagnosis method of a hybrid vehicle that runs on at least one of a motor and gasoline fuel,

a) Receiving a plurality of information supplied from the outside to determine whether the driving stability condition is satisfied when the fuel leakage diagnosis condition is satisfied while driving; and as a result of determining whether the predetermined predetermined time has elapsed when the driving stability condition is satisfied. step;

b) closing the fuel tank under control of the canister shutoff valve and the canister purge valve when the predetermined time has elapsed;

c) measuring fuel evaporation after closing the fuel tank and then controlling the opening of the canister purge valve to lower the fuel pressure in the fuel tank;

d) calculating a fuel leakage amount and a fuel tank leakage magnitude calculated as the fuel pressure increase amount in the fuel tank by closing the canister purge valve when the fuel pressure in the fuel tank reaches a predetermined target value; And

e) It is determined whether the driving stability condition is satisfied based on a plurality of pieces of information during the execution of step d). If the determination result is not satisfied, the fuel leakage diagnosis is stopped and the number of diagnosis cancellations is increased and the diagnosis is increased. And terminating the program when the number of times of cancellation is greater than or equal to a predetermined set value.

Here, in step a), the fuel leakage diagnosis condition,

The battery voltage is 10V or more and 16V or less, the engine is burning through lambda control, the atmospheric pressure is 750 hPa or more, the residual gas in the canister is 0.38% or less of the total gas amount, the coolant temperature is 50 ° C or more and 142 ° C or less, and the atmosphere The temperature is -8 ° C or more and 62 ° C or less, the fuel level is 80% or less of the fuel amount of the total fuel tank, the purge is sufficiently carried out, the evaporation gas pressure in the fuel tank is -11 hPa or more and 4 hPa or less, the vehicle speed sensor, It is characterized in that the diagnostic results for the various electrical equipment such as the purge valve is normal,

In step a), the driving stability condition is,

The fuel tank change amount is 3% / sec or less, the intake air amount change is 50 mg / s or less, the engine load change amount is 2% / sec or less, and the cumulative value for the throttle valve change amount is 1500 deg * sec or less, The change in the rotational acceleration of the wheel is less than 10 per mille / sec, there is no misfire, it is characterized in that the driving on the unpaved road.

In addition, the method,

In the step b), further comprising the step of indicating that the fuel leakage diagnostics when driving the engine according to the fuel leakage diagnosis,

In addition, the method may further include displaying, in step e), the fuel leakage diagnosis result to the driver after completing the fuel leakage diagnosis when the driving stability condition is satisfied.

According to the present invention, when the predetermined fuel leakage diagnosis condition and the driving stability condition are satisfied while the vehicle is running, the fuel leakage diagnosis of the fuel tank is executed by controlling the canister purge valve and the canister shutoff valve, and the fuel leakage is diagnosed during the fuel leakage diagnosis. If the diagnosis condition is not satisfied, the fuel leakage diagnosis is stopped, and the fuel leakage diagnosis is executed even while the hybrid vehicle is running, thereby preventing the emission of harmful gases due to the leakage of the evaporated gas from the fuel tank, thereby preventing environmental pollution. .

Hereinafter, the most preferred embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention in detail.

FIG. 1 is a diagram illustrating an evaporation gas control system of a hybrid vehicle to which the present invention is applied, and FIG. 2 is a flowchart illustrating a fuel leakage diagnosis process of a fuel tank of an engine control unit illustrated in FIG. 1.

Here, a conventional evaporative gas control system installed in a hybrid vehicle that runs by using a motor and gasoline fuel includes a fuel tank 210 and a fuel tank 210 for storing fuel of an automobile as shown in FIG. 1. A supply pipe connected to a pipeline to supply an evaporation gas collector 215 for collecting the evaporated gas generated from the fuel tank 210, and an evaporation gas of the evaporation gas collector 215 to the engine 220 of the vehicle ( A canister shutoff valve 260 for selectively opening and closing a connection between the evaporative gas collector 215 and the outside air to diagnose a fuel leak; A canister purge valve 270 interposed on the supply conduit 225 to adjust an amount of the evaporated gas supplied from the evaporative gas collector 215 to the engine 220; And an engine control unit 250 for controlling the canister shutoff valve 260 and the canister purge valve 270 and diagnosing the leakage of the boil-off gas control system based on signals input from the sensors 230, 235, and 240. "ECU").

Although the example of the evaporative gas control system has been described as including an evaporative gas collector 215, even if it does not include the leak detection method of the present invention can be applied, in this case the canister shutoff valve 260 May be interposed at any position from which it is possible to select whether or not to block outside air on the evaporative gas control system.

Here, when the ECU 250 satisfies a predetermined fuel leakage diagnosis condition and a driving stability condition while driving the vehicle, the ECU 250 controls the fuel of the fuel tank 210 through the control of the canister purge valve 270 and the canister shutoff valve 260. It is arranged to execute the leak diagnosis and stop the fuel leak diagnosis when the fuel leak diagnosis condition is not satisfied during the fuel leak diagnosis.

Here, the fuel leakage diagnosis condition is that the battery voltage is 10V or more and 16V or less, the engine is being burned by lambda control, the atmospheric pressure is 750 hPa or more, the residual gas in the canister is 0.38% or less of the total gas amount, and the coolant temperature is 50 ° C or more and 142 ° C or less, atmospheric temperature is -8 ° C or more and 62 ° C or less, the fuel level is 80% or less of the fuel amount of the total fuel tank, purging is sufficiently performed, and the evaporation gas pressure in the fuel tank is -11 hPa It is a case where it is more than 4 hPa, and the diagnostic result about various electrical appliances, such as a vehicle speed sensor and a purge valve, is normal.

In addition, the driving stability conditions, the fuel amount change amount of the fuel tank is 3% / sec or less, the intake air amount change amount is 50 mg / s or less, the engine load change amount is 2% / sec or less, the cumulative value for the throat valve change amount It is 1500 deg * sec or less, the rotational acceleration change amount of a wheel is 10 per millimeters / sec or less, there is no misfire, and it is running on the unpaved road.

The fuel leakage diagnosis process of the hybrid vehicle according to the exemplary embodiment of the present invention described above will be described with reference to FIG. 2.

First, the engine control unit 250 receives a plurality of information supplied from the outside in step 101 and determines whether the fuel leakage diagnosis condition is satisfied based on the received plurality of information in step 103. do.

Then, the engine control unit 250 proceeds to step 105 when the fuel leakage diagnosis condition is satisfied, and in step 105, the engine control unit 250 determines whether the predetermined driving stability condition is satisfied.

If the determination result of the step 105 satisfies the driving stability condition, it is determined whether a predetermined predetermined time has elapsed (step 107). If the predetermined time has elapsed, the fuel leakage diagnosis is performed. At this time, the engine control unit 250 displays that the fuel leakage diagnosis.

That is, the engine control unit 250 seals the fuel tank through the closing control of the canister shutoff valve 260 and the canister purge valve 270 through step 109, and then measures the amount of evaporation in the fuel tank (step 111).

In addition, the engine control unit 250 controls the opening of the canister purge valve 270 to lower the fuel pressure in the fuel tank (step 113), and determines whether the fuel pressure in the fuel tank has reached a predetermined target value (step). 115).

When the fuel pressure in the fuel tank reaches the target value as a result of the determination of step 115, the canister purge valve 270 is closed-controlled (step 117).

The engine control unit 250 then measures the fuel leakage in the fuel tank through step 119 and measures the leakage size of the fuel tank based on the measured fuel leakage.

During the execution of the step 119, the engine control unit 250 collects a plurality of pieces of information supplied from the outside (step 121) to determine whether the driving stability condition is satisfied (step 123), and as a result, the driving stability If the condition is satisfied, the fuel leakage diagnosis is completed (step 125), and then the leakage diagnosis result is displayed.

However, if the driving stability condition is not satisfied at step 123, the process proceeds to step 127. At step 127, the diagnosis of leakage is stopped and the number of diagnosis cancellations is subsequently increased (step 129). It is determined whether the number of times is greater than or equal to a predetermined set value (step 131).

In the step 131, the program is terminated when the number of times of canceling the diagnosis is greater than or equal to the set value.

As described above, when the fuel leakage diagnosis condition is satisfied while driving the hybrid vehicle, fuel leakage diagnosis is performed using a canister purge valve, a canister shutoff valve, and a purge valve, and the fuel leakage diagnosis is performed. If the fuel leakage diagnosis condition is not satisfied in the meantime, the fuel leakage diagnosis can be stopped while the fuel leakage diagnosis is stopped, thereby preventing harmful gas emissions due to fuel leakage in the fuel tank, thereby preventing environmental pollution. Product reliability can be further improved.

As such, those skilled in the art to which the present invention pertains will understand that the present invention may be embodied in other specific forms without changing to the technical spirit or essential features of the present invention. Therefore, the above-described embodiments are to be understood in all respects as illustrative and not restrictive. The scope of the invention is indicated by the following claims rather than the above description, and it should be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalents are included in the scope of the invention. .

1 is a view showing an evaporation gas control system of a hybrid vehicle to which the present invention is applied.

2 is a flowchart illustrating a fuel leakage diagnosis process of a fuel tank of a hybrid vehicle according to the present invention.

Claims (5)

In the fuel leakage diagnosis method of a hybrid vehicle that runs on at least one of a motor and gasoline fuel, a) Receiving a plurality of information supplied from outside to determine whether the driving stability condition is satisfied when the fuel leakage diagnosis condition is satisfied while driving, and if the predetermined stability time is passed when the driving stability condition is satisfied as a result of the determination step; b) closing the fuel tank under control of the canister shutoff valve and the canister purge valve when the predetermined time has elapsed; c) measuring fuel evaporation after closing the fuel tank and then controlling the opening of the canister purge valve to lower the fuel pressure in the fuel tank; d) calculating a fuel leakage amount and a fuel tank leakage magnitude calculated as the fuel pressure increase amount in the fuel tank by closing the canister purge valve when the fuel pressure in the fuel tank reaches a predetermined target value; And e) It is determined whether the driving stability condition is satisfied based on a plurality of pieces of information during the execution of step d). If the determination result is not satisfied, the fuel leakage diagnosis is stopped and the number of diagnosis cancellations is increased and the diagnosis is increased. And terminating the program when the number of times of cancellation is greater than or equal to a predetermined set value. The fuel leakage diagnosis condition of claim 1, wherein The battery voltage is 10V or more and 16V or less, the engine is burning through lambda control, the atmospheric pressure is 750 hPa or more, the residual gas in the canister is 0.38% or less of the total gas amount, the coolant temperature is 50 ° C or more and 142 ° C or less, and the atmosphere The temperature is -8 ° C or more and 62 ° C or less, the fuel level is 80% or less of the fuel amount of the total fuel tank, the purge is sufficiently carried out, the evaporation gas pressure in the fuel tank is -11 hPa or more and 4 hPa or less, the vehicle speed sensor, A method for diagnosing fuel leakage in a hybrid vehicle, characterized in that the diagnosis result for each electric equipment such as a purge valve is normal. The driving stability condition according to claim 1 or 2, wherein in the step a), The amount of fuel change in the fuel tank is 3% / sec or less, the intake air amount is 50 mg / s or less, the engine load change is 2% / sec or less, and the cumulative value for the throat valve change is 1500 deg * sec or less. The fuel leakage diagnosis method of a hybrid vehicle, characterized in that the rotational acceleration change amount of the wheel is 10 per milli / sec or less, no misfire, and driving on a dirt road. The method of claim 3, wherein the method is In step b), the fuel leakage diagnostic method of the hybrid vehicle, characterized in that further comprising the step of indicating that the fuel leakage diagnosis during the engine driving according to the fuel leakage diagnosis. The hybrid vehicle of claim 4, further comprising, in step e), displaying a fuel leakage diagnosis result to a driver after completing the fuel leakage diagnosis when the driving stability condition is satisfied. Fuel leakage diagnostic method.

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