KR101947359B1 - Method and system for diagnosing fuel leakage in eol - Google Patents

Method and system for diagnosing fuel leakage in eol Download PDF

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KR101947359B1
KR101947359B1 KR1020120095263A KR20120095263A KR101947359B1 KR 101947359 B1 KR101947359 B1 KR 101947359B1 KR 1020120095263 A KR1020120095263 A KR 1020120095263A KR 20120095263 A KR20120095263 A KR 20120095263A KR 101947359 B1 KR101947359 B1 KR 101947359B1
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South Korea
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purge valve
fuel
leakage
predetermined
diagnosis
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KR1020120095263A
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Korean (ko)
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KR20140028631A (en
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김한신
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콘티넨탈 오토모티브 시스템 주식회사
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

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  • Chemical & Material Sciences (AREA)
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Abstract

The present invention discloses a method and system for diagnosing fuel leakage in an EOL process. According to the present invention, after the engine is stopped, the canister purge valve is controlled to open to form the fuel tank at atmospheric pressure. Then, the leakage of the fuel tank is detected based on the connection time and the connection time of the fuel pressure switch provided in the fuel tank, Size and small-scale leakage and purge valve error. When the fuel pressure switch is not connected after a predetermined criterion time elapses, the purge valve is controlled to open at a preset value based on the purge valve opening control signal, The failure diagnosis of the purge valve and the large-scale leakage diagnosis result are derived based on the noise component pattern and the purge valve opening control signal supplied from the manifold pressure sensor, so that the leak diagnosis of the fuel tank using the natural negative pressure can be executed in the EOL process .

Description

[0001] METHOD AND SYSTEM FOR DIAGNOSING FUEL LEAKAGE IN EOL [0002]

The present invention relates to a method and system for diagnosing fuel leakage in an EOL process, and more particularly, to a method and system for diagnosing fuel leakage in an EOL process. More specifically, after the engine is stopped, a canister purge valve is opened to control the fuel pressure of the fuel tank to a natural negative pressure And a system and method for determining the leakage size of the fuel tank and whether or not the purge valve is normal based on the connection time of the fuel pressure switch that generates the connection signal in accordance with the fuel pressure of the fuel tank.

In the final stage of the vehicle manufacturing process, an end of line (EOL) process is usually performed to diagnose the abnormality of each function of the produced vehicle.

Such EOL (End Of Line) process checks whether or not each function of the vehicle to be inspected is abnormal. Among these functions, the diagnosis of the leakage in the fuel tank is also included.

The leakage diagnosis of the fuel tank during engine stopping normally forms a negative pressure in the fuel tank through the control of the canister purge valve and then executes the leak diagnosis in the fuel tank based on the change of the fuel pressure in the fuel tank through the control of the purge valve.

However, in the EOL process, the fuel tank leak diagnosis is a forced leakage diagnosis method that executes the fuel tank leak diagnosis by confirming fuel pressure change of the fuel tank by forcibly interrupting the canister purge valve and the purge valve through external equipment during engine operation .

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide an EOL process, Based on the connection time of the fuel pressure switch connected to the fuel pressure switch of the fuel tank when the fuel pressure of the fuel tank is lowered to a predetermined pressure, The fuel leak diagnosis method in the EOL process for diagnosing at least one of the small leakage and leak size of the purge valve and the normal purge valve in the EOL process can be performed using the natural negative pressure mode in the EOL process.

It is a further object of the present invention to provide a fuel pressure switch for a fuel pressure switch in which a fuel pressure switch is not connected even after a predetermined time has elapsed, The fuel leakage detection method in the EOL process for diagnosing at least one of the normal state and the large leakage of the purge valve based on the noise component pattern of the purge valve opening control signal and the intake manifold pressure sensor for controlling opening to predetermined predetermined values It is possible to diagnose the fixing error of the fuel pressure switch by using the natural negative pressure mode in the EOL process.

According to an aspect of the present invention, there is provided a fuel leakage diagnosis method in an EOL process,

A method for diagnosing a fuel leak in an EOL process, comprising a diagnosis control section for interrupting a canister purge valve and a purge valve to diagnose fuel leakage based on a change in fuel pressure after forming a negative pressure in a fuel tank,

Wherein the diagnostic control unit performs the fuel leak diagnosis condition in the predetermined EOL process based on the diagnosis result of the fuel leak diagnosis related component, the battery voltage, the load of the canister purge valve, the cooling water temperature, the ambient temperature, the fuel temperature, A natural negative pressure setting step of opening and closing the canister purge valve for a predetermined time after the engine is stopped to set the fuel pressure of the fuel tank at atmospheric pressure; And

The fuel leakage amount is calculated based on the connection time of the fuel pressure switch connected when the fuel pressure of the descending fuel tank reaches a preset predetermined pressure by controlling the purge valve to open after the engine is started, And a first diagnostic step of determining whether or not the small leak of the fuel tank and the purge valve are in error according to whether or not the purge valve is open.

Preferably, the first diagnostic step comprises:

The leakage magnitude is derived based on the connection time from the opening control point of the purge valve to the time point at which the fuel pressure switch is connected and the connection signal is generated to determine a small leakage according to the leakage magnitude, And to determine the purge valve steady state according to the determination result.

Preferably,

And is derived on the basis of a predetermined proportional relation with respect to the connection time of the fuel pressure switch.

Preferably, the first diagnostic step comprises:

And judging that there is no small-scale leak and purge valve error when the leakage size is equal to or less than a predetermined judgment allowable value.

Preferably, the judgment allowable value for the connection time of the fuel pressure switch is

The fuel level, the fuel gas evaporation amount, the purge valve opening period, the amount of opening of the purge valve, and the fuel characteristic, and stored as a lookup table value.

Preferably, the first diagnostic step comprises:

And when the leakage size is not less than the allowable value, the leakage size is displayed and it is determined that there is no purge valve error.

Preferably,

A purge valve opening control signal for controlling opening of the purge valve to a preset predetermined value when the fuel pressure switch is not connected even after a predetermined determination reference time has elapsed and then supplying the purge valve opening control signal to the purge valve, Obtaining a noise component generated from a pressure sensor installed at a predetermined position of the intake manifold according to the signal;

And a second diagnostic step of determining at least one of an error and a large-scale leakage of the purge valve based on the noise component pattern of the pressure sensor and the purge valve opening control signal.

Preferably, the second diagnostic step comprises:

And a large-scale leakage of the fuel tank when the noise component pattern of the pressure sensor coincides with the opening control signal of the purge valve,

Increasing the purge valve error counter when the noise component pattern of the pressure sensor does not coincide with the opening control signal of the purge valve and increasing the purge valve error counter to a predetermined number of times, It is determined that there is none.

Preferably,

And transmitting the result of the fuel leakage diagnosis in the EOL process to an external equipment (scan tool) and notifying the result.

Preferably, the method further comprises:

And proceeding to the fuel leak diagnosis cancel mode in the EOL process and deleting the fuel leak diagnosis result when the fuel leak diagnosis condition in the EOL process is not satisfied; And

Further comprising the step of informing the external equipment that the cause of the fuel leakage diagnosis is canceled.

Technical Solution According to another aspect of the present invention,

And a diagnosis control section for performing a fuel leak diagnosis on the basis of the fuel pressure that varies after the natural negative pressure is set after the fuel pressure of the fuel tank is controlled in accordance with the control of the canister purge valve and the purge valve,

Wherein the diagnosis control unit comprises:

An atmospheric pressure setting unit for controlling the opening of the canister purge valve for a predetermined period of time after the engine stops when the fuel leak diagnosis condition is satisfied in the EOL process to form the fuel pressure of the fuel tank at a natural negative pressure (atmospheric pressure)

A fuel pressure lowering part for lowering the fuel pressure by controlling opening and closing of the engine starting and purge valve after the lapse of the predetermined time,

A timer for starting counting from the opening control point of the purge valve,

A connection signal receiving section for receiving a connection signal of the fuel pressure switch generated by the fuel pressure switch connected when the fuel pressure of the fuel tank descending by the fuel pressure drop section reaches a predetermined predetermined pressure,

Wherein the timer counts up when receiving the connection signal of the connection signal receiving unit, and determines whether or not the connection time from the purge valve opening control point to the fuel pressure switch connection point, the fuel pressure switch connection, And a judging section for judging whether or not the small leak and the purge valve are normal based on the derived leak size.

Preferably,

The leakage size is derived based on the connection time of the fuel pressure switch,

And the small leakage and the purge valve are determined to be normal when the derived leakage size is equal to or less than a predetermined allowable value.

Preferably,

And when the derived leakage size is not less than the allowable value, it is determined that the leakage size indication and the purge valve are normal.

Preferably,

When the connection signal of the fuel pressure switch is not received after a predetermined reference time elapses, the purge valve is controlled to be open to a preset predetermined value, and based on the noise component pattern and the purge valve opening control signal supplied from the pressure sensor of the intake manifold And determines whether or not the purge valve is normal and large-scale leakage.

Here,

When the pattern of the noise component and the purge valve opening control signal coincide with each other, it is determined that the purge valve is normal and large-

When the pattern of the noise component does not coincide with the purge valve opening control signal, the purge valve error counter is increased, and when the increased purge error counter reaches a predetermined number of times, it is determined that there is no purge valve error and leakage I will do it.

As described above, in the method and system for diagnosing fuel leakage in the EOL process according to the embodiment of the present invention, after the engine is stopped, the canister purge valve is opened and controlled to form the fuel tank at atmospheric pressure, The leakage size of the fuel tank and the result of diagnosis of the small leakage and purge valve error are derived based on whether or not the fuel pressure switch installed in the tank is connected and the connection time. When the fuel pressure switch is not connected after the predetermined reference time, Based on the opening control signal, the purge valve is controlled to open at a preset value. Then, based on the noise component pattern supplied from the pressure sensor of the intake manifold and the purge valve opening control signal, , Leakage of fuel tank using natural negative pressure in EOL process Thereby obtaining the effect of executing the diagnosis.

1 is a view showing a configuration of a fuel leakage diagnosis system in an EOL process according to an embodiment of the present invention.
FIG. 2 is a diagram showing a configuration of the diagnostic control unit shown in FIG. 1. FIG.
3 is a flowchart illustrating a fuel leak diagnosis process in the EOL process according to the embodiment of the present invention.

In order to fully understand the present invention, operational advantages of the present invention, and objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the accompanying drawings which illustrate preferred embodiments of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the preferred embodiments of the present invention with reference to the accompanying drawings. Like reference symbols in the drawings denote like elements.

FIG. 1 is a view showing a fuel leakage diagnosis system in an EOL process to which an embodiment of the present invention is applied, and FIG. 2 is a diagram showing the configuration of the diagnosis control unit shown in FIG. The fuel leakage diagnosis system in the EOL process according to the embodiment of the present invention will be described as an example only with reference to the fuel leak diagnosis system shown in Figs. 1 and 2

1, the canister purge valve 10, the purge valve 30, the fuel tank 50, the fuel pressure switch 70, And a diagnosis control unit 90. [

Here, if the canister purge valve 10 satisfies the fuel leak diagnosis condition in the predetermined EOL process, the canister purge valve 10 is controlled to open for a predetermined time after the engine is stopped to set the fuel pressure of the fuel tank 50 at atmospheric pressure . At this time, the canister purge valve 10 is fully open controlled to 100% of the total opening amount.

Here, the fuel leakage diagnosis condition in the EOL process is that the fuel leak diagnosis related parts are normal, the battery voltage is 40% or more of the total filling rate, the canister purge valve load is 1.5 or less, the cooling water temperature is 80 degrees or less, The outdoor air temperature is 35 degrees or less, the fuel temperature is equal to or less than a predetermined reference value, the fuel level is equal to or less than a predetermined allowable value, and the leakage diagnosis allowable time has not elapsed.

Here, the fuel leakage diagnosis condition in the EOL process is a result value obtained through a number of experiments by the manufacturer, and is stored in advance in the diagnosis control unit 90 as a table value.

The purge valve 30 is provided to close the canister purge valve 10 after the lapse of the predetermined time (10 seconds), to control the opening of the canister purge valve 10 after starting the engine, thereby reducing the fuel pressure in the fuel tank 50. The purge valve opening control signal provided to the purge valve 30 is set such that the fuel pressure of 0.3-0.6 kg / h is set to fall for a predetermined first predetermined time (0.2 second), and a second predetermined time 0.8 seconds). The purge valve opening control signal is repeatedly generated for the determination reference time (30 seconds).

At this time, the fuel pressure switch automatically connects when the fuel pressure in the fuel tank 50 descending in accordance with the opening control of the purge valve 30 reaches a predetermined pressure to generate a fuel pressure switch connection signal, And provides the pressure switch connection signal to the diagnosis control unit 90.

On the other hand, the diagnosis control unit 90 derives the leakage size based on the connection time from the starting point of time when the fuel pressure of the fuel tank 50 falls (the control point of the purge valve opening control) to the point of time when the fuel pressure switch connection signal is received And determines whether or not the purge valve is normal depending on the derived leakage size and whether or not the fuel pressure switch is connected.

Since the connection time varies depending on the fuel level, the fuel gas evaporation amount, the purge valve opening amount, the fuel property, and the leakage size, the opening time of the purge valve, Opening amount should be adjusted.

For example, if the fuel level is lower than the predetermined fuel level, the opening amount of the purge valve is controlled to be 0.45 kg / h for 0.2 seconds and then closed for 0.8 seconds. If the fuel level is higher than the set fuel level The amount of opening of the purge valve is set so as to supply 0.3 kg / h of gas to the engine.

Further, it may be set to perform the fuel leak diagnosis under the cooling condition equal to or lower than a predetermined set temperature in order to prevent the variation of the connection time by the fuel characteristic and the fuel gas evaporation amount.

The diagnosis control unit 90 is provided to execute a second diagnosis for determining whether the purge valve is an error or a large leak when the fuel pressure switch connection signal is not received after a lapse of a predetermined determination reference time.

That is, the diagnosis control unit 90 generates a purge valve opening signal for controlling opening by a preset predetermined value and provides the signal to the purge valve 30. At this time, according to the driving of the purge valve 30, It is determined that the purge valve 30 is normal and fuel large-scale leakage when the received noise component pattern and the purge valve opening signal coincide with each other.

Here, the purge valve opening control signal is set to a certain ratio (30-60%) with respect to the total opening amount for a predetermined time (3-5 seconds).

2, the diagnostic control unit 90 that executes this series of processes includes an atmospheric pressure setting unit 91, a fuel pressure lowering unit 92, a timer 93, a connection signal receiving unit 94, (95).

The diagnostic unit 90 may further include a display unit 96 for transmitting and displaying the leakage diagnosis result of the determination unit 95. [

The atmospheric pressure setting unit 91 is provided to set the fuel pressure of the fuel tank 50 at a natural negative pressure (atmospheric pressure) by controlling the opening of the canister purge valve 10 for a predetermined period of time after the engine is stopped.

When the predetermined time has elapsed, the fuel pressure lowering portion 92 is provided to lower the fuel pressure of the fuel tank 50 by controlling the opening of the purge valve 30 after the start of the engine.

At this time, the timer 93 outputs a connection signal of the fuel pressure switch connected when the fuel pressure of the fuel tank 50 reaches the predetermined value from the time when the purge valve is opened after the start of the engine to the connection time .

The connection signal receiving unit 94 is connected to generate a connection signal when the fuel pressure of the fuel tank 30 reaches a preset predetermined value by the fuel pressure lowering unit 92.

The connection signal is provided to the timer 93 so that the driving of the timer 93 is stopped and the count value of the timer 93 is supplied to the judging unit 95. [

On the other hand, the judging unit 95 is provided for judging the fuel leakage size and whether or not the purge valve is normal based on the count values of the connection signal receiving unit 94 and the timer 93.

That is, when the connection signal is received, the determination unit 95 derives the leakage size based on the count value of the timer 93, and determines that the small leakage and purge valve is normal when the leakage size is equal to or less than the predetermined determination allowable value .

Further, the determination unit 95 determines that the leakage size and the purge valve are normal when the leakage size is not less than the determination allowable value.

The judging unit 95 receives the pattern of the noise component supplied from the intake manifold after executing the purge valve opening control when the connection signal has passed the predetermined criterion time and the connection signal is not received.

If the noise component pattern coincides with the purge valve open control signal, the purge valve error counter is increased when the noise component pattern does not coincide with the purge valve open control signal. , And when the increased purge valve error counter reaches the predetermined number (3 times), it is determined that there is no purge valve error and leakage.

The diagnosis control unit 90 may further include a notification unit 96 for transmitting the fuel leakage diagnosis result of the determination unit 95 to an external device. The external device may include a scan tool, A series of processes for displaying the diagnostic result using the tool is a well-known technique widely known to those skilled in the art.

If the fuel leakage diagnosis condition is not satisfied, the diagnosis control unit 90 transmits the reason for canceling the fuel leakage diagnosis after the determination of the fuel leakage diagnosis by the determination unit 95 to the external device through the notification unit 96 Configuration may be further included.

The fuel tank is set at atmospheric pressure by controlling the opening of the canister purge valve after the engine is stopped, and then the fuel pressure switch installed in the fuel tank is controlled to open the purge valve, A series of processes for deriving an error diagnosis result and for diagnosing a failure of the purge valve and a large-scale leak diagnosis when the fuel pressure switch is not connected after a predetermined reference time has elapsed will be described in more detail with reference to FIG. 3 .

3 is a flowchart showing a fuel leak diagnosis process in the EOL process executed by the diagnostic control unit 90 shown in FIG.

Referring to FIG. 3, the process of diagnosing fuel leakage in the EOL process, which is another embodiment of the present invention, will be described in more detail.

First, the diagnosis control unit 90 determines whether the fuel leak diagnosis condition in the EOL process is satisfied based on the fuel leak diagnosis related information supplied from the outside (step 101). If the fuel leak diagnosis condition is satisfied as a result of the determination, After stopping, the canister purge valve 10 is controlled to open for a predetermined time (steps 103, 105, 107).

At this time, the canister purge valve 10 controls 50-100% opening based on the total open amount, and therefore the fuel pressure of the fuel tank 50 is set to the natural negative pressure (atmospheric pressure).

Here, the process of controlling the opening of the canister purge valve is similar to the process of controlling the opening of the canister purge valve in order to form a negative pressure in the fuel tank when a general fuel leak occurs, and thus a detailed description thereof will be omitted.

When a predetermined time elapses in step 107, the diagnosis controller 90 controls the purge valve to open after the engine is started, and then starts counting the timer (steps 109, 111, and 113). At this time, the purge valve 30 is controlled so as to discharge gas (0.3-0.6 kg / h) for a predetermined time (0.2 second) and is closed-controlled again for 0.8 second, so that the fuel pressure of the fuel tank 50 is lowered do.

Here, the process of controlling the opening of the purge valve is similar to the process of controlling the opening of the purge valve when the fuel is leaking, and therefore, a detailed description thereof will be omitted.

In step 111, when the fuel pressure of the fuel tank descending through the purge valve opening control reaches a predetermined value, the diagnosis control unit 90 determines that the fuel pressure switch is connected and the generated connection signal is received When the access signal is received as a result of the judgment, the counting of the timer is terminated (steps 115 and 117).

At this time, the diagnosis control unit 90 derives the fuel leakage size based on the connection time of the fuel switch of the received timer, and determines whether the small leakage or the purge valve is normal based on the derived fuel leakage size.

Here, the fuel leakage magnitude relative to the connection time is derived on the basis of a predetermined proportional relation, and the fuel leakage magnitude relative to the derived connection time is stored in advance in the diagnosis control unit 90 as a table value.

For example, if the connection time is within 0-15 seconds, the leakage size is determined to be 0-1.0 mm, and if the connection time is 15-30, the leakage size is determined to be 1.0-3.0 mm.

A series of processes for determining whether or not a small leak and a purge valve are normal by deriving the fuel leakage size based on the connection time of the timer will be described in more detail.

That is, the diagnostic control unit 90 derives the leakage size of the timer stored as the table value through step 119, and if the derived fuel leakage size is less than the judgment allowable value (0.5 mm), the small- (Steps 119, 121 and 123)

On the other hand, if the fuel leakage size is not less than 0.5 mm in step 121, the diagnosis controller 90 outputs the derived leakage size and determines that the purge valve is normal (step 125).

On the other hand, if the connection signal of the fuel pressure switch is not received in step 115, the diagnosis control unit 90 determines whether a predetermined determination reference time (30 seconds) has elapsed. If it is determined that the determination reference time has elapsed A purge valve opening control signal for generating a purge valve opening control signal of a preset predetermined value is provided to the purge valve, and the noise supplied from the intake manifold is received (steps 131 and 133).

Here, the purge valve opening control signal is set to a predetermined amount (30-60%) with respect to the total opening amount for a predetermined time (0.3 seconds). Next, the noise component pattern supplied from the pressure sensor of the intake manifold is compared with the purge valve opening control signal to determine whether they match (step 135).

If the pattern of the noise component pattern and the purge valve opening control signal coincide with each other in step 135, the diagnostic control unit 90 determines the purge valve as normal and judges as a large-scale leak through step 137.

However, if the pattern of the noise component does not coincide with the pattern of the purge valve opening control signal in step 135, the diagnosis control unit 90 increases the purge valve error counter through step 139, The purge valve error counter reaches the predetermined number of times (3), it proceeds to step 143 to determine no purge valve error and no fuel leakage.

On the other hand, the diagnosis control unit 90 notifies the manufacturer of the fuel leakage and purge valve diagnosis results at the steps (123, 125, 137, 143) to the external device (step 145)

On the other hand, if the fuel leak diagnosis condition is not satisfied in step 101, the diagnosis control unit 90 proceeds to step 147 to set the fuel leak diagnosis termination mode, and then diagnoses the fuel leakage and the purge valve And proceeds to step 147 to notify the manufacturer of the cause of the fuel leak diagnosis termination.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

The fuel tank is controlled to be open to control the opening of the canister purge valve after the engine is stopped to control the opening degree of the fuel tank and the connection time of the fuel pressure switch provided in the fuel tank, And when the fuel pressure switch is not connected after a predetermined reference time elapses, the purge valve is controlled to be open to a preset predetermined value based on the purge valve opening control signal, and then the pressure sensor of the intake manifold Fuel leakage diagnosis system in EOL process which can perform leak diagnosis of fuel tank using natural negative pressure in EOL process by deriving fault diagnosis and large scale leak diagnosis result of purge valve based on noise component pattern and purge valve opening control signal And accuracy of the operation and reliability of the method Surface, a further extremely may lead to great advances, in the invention, commercially available, or because the degree Industrial Applicability sufficient possibility of operating not only to obviously practical embodiment of a vehicle that is applied to performance efficiency.

Claims (15)

A method for diagnosing fuel leakage in an EOL process,
Setting a fuel pressure of the fuel tank to an atmospheric pressure by controlling opening of the canister purge valve for a predetermined period of time after the engine is stopped when the diagnostic control unit satisfies the fuel leak diagnosis condition in the predetermined EOL process;
After the start of the engine, the purge valve is controlled to be opened to lower the fuel pressure of the fuel tank, and the leakage size is derived based on the connection time of the fuel pressure switch connected when the fuel pressure of the fuel tank reaches the predetermined pressure, A first diagnostic step of judging whether a leakage of the fuel tank and an error of the purge valve are in accordance with the leakage size and whether or not the fuel pressure switch is connected;
A purge valve opening control signal for controlling opening of the purge valve to a preset predetermined value is generated and supplied to the purge valve when the fuel pressure switch is not connected even after a lapse of a predetermined reference time, Obtaining a noise component pattern from the installed pressure sensor; And
And a second diagnostic step of determining an error and a large-scale leakage of the purge valve based on the noise component pattern and the purge valve opening control signal. 2. The method according to claim 1,
The leakage magnitude is derived based on the connection time from the opening control point of the purge valve to the time point at which the fuel pressure switch is connected and the connection signal is generated and a small leakage is judged according to the leakage magnitude, And determining whether or not a purge valve error has occurred. The method of claim 1,
Wherein the fuel leakage amount is derived on the basis of a predetermined proportional relation to the connection time of the fuel pressure switch. 2. The method according to claim 1,
And when the leakage size is equal to or less than a predetermined determination allowable value, it is determined that there is no small-scale leakage and purge valve error. 2. The fuel pressure switch according to claim 1,
Fuel ratio, fuel level, fuel gas evaporation amount, purge valve opening period, purge valve opening amount, fuel characteristic, and stored as a look-up table value. 2. The method according to claim 1,
And when the leakage size is not less than the judgment allowable value, the leakage size is displayed and it is judged that there is no purge valve error. delete 2. The method of claim 1,
When the noise component pattern coincides with the purge valve opening control signal, it is determined that there is no purge valve error and large-scale leakage,
The purge valve error counter is increased when the noise component pattern does not coincide with the purge valve opening control signal and the purge valve error is determined to be no leakage when the increased purge valve error counter reaches a predetermined number of times Wherein the fuel leakage diagnosis method comprises: The method of claim 1,
Further comprising the step of notifying the external equipment of the result of the fuel leakage diagnosis in the EOL process and notifying the external equipment of the result of the fuel leakage diagnosis. The method of claim 1,
And proceeding to the fuel leak diagnosis cancel mode in the EOL process and deleting the fuel leak diagnosis result when the fuel leak diagnosis condition in the EOL process is not satisfied; And
Further comprising the step of notifying the external equipment that the reason for the termination of the fuel leak diagnosis is transmitted to the external equipment. A fuel leak diagnosis system in an EOL process including a diagnosis control section for performing a fuel leak diagnosis of a fuel tank,
Wherein the diagnosis control unit comprises:
An atmospheric pressure setting unit configured to open and control the canister purge valve for a predetermined period of time after the engine stops when the fuel leak diagnosis condition in the EOL process satisfies the condition,
A fuel pressure lowering part for starting the engine after the lapse of the predetermined time and controlling the opening of the purge valve to lower the fuel pressure,
A timer for starting counting from the opening control point of the purge valve,
A connection signal receiving unit for receiving a connection signal generated in a fuel pressure switch connected when the fuel pressure of the fuel tank descending by the fuel pressure drop portion reaches a predetermined predetermined pressure,
Wherein the timer counts up when receiving the connection signal of the connection signal receiving unit, and determines the connection time from the purge valve opening control time point to the fuel pressure switch connection point, whether or not the fuel pressure switch is connected, And a judging section for judging whether or not the small leak and the purge valve are erroneous,
The judging unit judges,
When the fuel pressure switch is not connected even after a lapse of a predetermined criterion time has elapsed, a purge valve opening control signal for controlling opening of the purge valve to a preset predetermined value is generated and supplied to the purge valve, And to determine an error and a large-scale leakage of the purge valve based on the noise component pattern obtained from the sensor and the purge valve opening control signal. 12. The image processing apparatus according to claim 11,
The leakage size is derived based on the connection time of the fuel pressure switch,
And the small leak and the purge valve are judged to be normal when the derived leakage size is less than a predetermined judgment allowable value. 13. The apparatus according to claim 12,
And if the derived leakage size is not less than the predetermined determination allowable value, the leakage size is displayed and it is determined that there is no purge valve error. delete 12. The image processing apparatus according to claim 11,
When the noise component pattern matches the purge valve opening control signal, it is determined that there is no purge valve error and a large-scale leak,
The purge valve error counter is incremented when the noise component pattern does not match the purge valve opening control signal and the purge valve error and leakage are judged to be absent when the increased purge error counter reaches a predetermined number of times Fuel Leakage Diagnosis System.
KR1020120095263A 2012-08-29 2012-08-29 Method and system for diagnosing fuel leakage in eol KR101947359B1 (en)

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