KR100779840B1 - Apparatus and method for diagonsing fuel supplying apparatus of lpi car - Google Patents

Abstract

An apparatus and a method for diagnosing a fuel supply system of an LPI vehicle are provided to prevent abnormal high pressure of a fuel supply line caused due to faults of a third fuel cutoff valve. An apparatus for diagnosing a fuel supply system of an LPI vehicle includes a sub ECU(33) for diagnosing faults of a third fuel cutoff valve(SV3) on the basis of a first fuel pressure of a fuel supply line measured after elapse of a first preset time after shutting a first fuel cutoff valve(SV1) and a second fuel cutoff valve(SV2) and a second fuel pressure of the fuel supply line measured after elapse of a second preset time after shutting the third fuel cutoff valve when a start key signal is OFF and a fuel pump(13) is turned off. The sub ECU increases a diagnosis counter if the second fuel pressure is larger than the difference between the first fuel pressure and a preset reference value, generates an error code if the frequency of counting of the diagnosis counter is more than a predetermined frequency, and stores the frequency of counting and the error code.

Description

TECHNICAL APPARATUS AND METHOD FOR Fault Diagnosis Of Fuel Supply Unit Of ELPIA Vehicle {APPARATUS AND METHOD FOR DIAGONSING FUEL SUPPLYING APPARATUS OF LPI CAR}

1 is a waveform diagram showing the fuel pressure of a typical fuel supply line.

2 is a view showing the configuration of a fuel supply device according to the invention.

3 is a waveform diagram showing the fuel pressure of the fuel supply line shown in FIG.

4 is a flowchart illustrating a control process of the fuel supply device according to the present invention.

<Explanation of symbols for the main parts of the drawings>

11: fuel tank 13: fuel pump

17 gas injector 21 fuel supply line

22: fuel return line 23: fuel pressure sensor

25 regulator 33: sub

SV1: first fuel shutoff valve SV2: second fuel shutoff valve

SV3: Third Fuel Shutoff Valve

The present invention relates to an apparatus and method for diagnosing a failure of a fuel supply device of an Elpia vehicle, and more particularly, to accurately detect a failure of a third fuel shutoff valve installed in a fuel return line based on a change in fuel pressure of a fuel supply line. An apparatus and method for making a diagnosis are provided.

Liquefied Petroleum Gas (Liquefied Petroleum Gas) fuel is used in some passenger cars and vans due to its high octane value, excellent heat resistance, and low fuel cost.

The LPG fuel supplied to the engine of the vehicle is a liquid phase, and when it is vaporized, it has a good mixing property with air and thus flammability, so knocking is less likely to occur than gasoline and diesel, and it is vapor-locked or percolated. As a substitute for gasoline or diesel fuel, the application range is gradually increasing.

Here, the LLP fuel device supplies the LLP fuel to the injector in the liquid phase by using a fuel pump, and injects LLP fuel into the cylinder through the injector, and the injected LLP fuel mixes air and vaporizes the engine. Drive it.

Accordingly, the combined Ellipse and gasoline vehicle uses a vaporizer, a mixer and an Elpigi fuel tank, a solenoid valve that controls the supply of Elpigi fuel, and an Elpigi II oil that controls the solenoid valve. It must be provided.

However, in recent years, LPI (Liquefied Petroleum Injection) method, which directly injects LPG into the combustion chamber through the injector control of Lee's oil, does not use a separate mixer and evaporator. Performance can be improved.

In such a general LPI vehicle, when the ignition switch is turned on, the fuel pump operates at the maximum speed in accordance with the pump control signal of the sub-EC oil so that the LLP fuel in the fuel tank is discharged in a liquefied state.

Subsequently, when the ignition switch is switched to the start position, the main ICC supplies the gasoline injection signal to the sub ISO in accordance with the amount of air, and the sub ISI generates the gas injection signal in accordance with the received gasoline injection signal. The gas injection signal is supplied to a gas injector, and, by the operation of the gas injector, the LLP fuel discharged through the fuel pump from the fuel tank is injected into the cylinder through the first and second fuel shutoff valves which are open controlled.

At this time, when the start key is turned on and fuel is supplied to the cylinder at high pressure through the fuel supply line, good startability can be maintained. During operation, the pressure of the fuel supply line is about 5 bar higher than the pressure in the fuel tank by the fuel pump. Is pressurized.

That is, when the start-off pressure of the fuel supply line is 5 bar than the pressure in the fuel tank, the driving of the fuel pump is stopped, the first fuel shut-off valve installed in the fuel supply line adjacent to the gas injector and the fuel tank The second fuel shutoff valve installed in the adjacent fuel supply line is closed-controlled, so that the fuel pressure of the fuel supply line is kept pressurized about 5 bar more than the pressure in the fuel tank.

In addition, when the ignition key is turned off, the excess fuel supplied to the gas injector by being controlled to be opened due to the power supply of the third fuel shutoff valve is returned to the fuel tank through the fuel return line. Therefore, the fuel pressure of the fuel supply line is lowered, as shown in FIG.

However, if a failure occurs due to mechanical failure or deterioration of the third fuel shutoff valve at the start key off and the drive signal off of the fuel pump, the fuel pressure of the fuel supply line is 5 bar pressure than the fuel pressure of the fuel tank. In this case, damage to the associated parts of the fuel supply device including the first fuel cutoff valve, the second fuel cutoff valve, and the like of the fuel supply line is maintained. Therefore, a separate device and logic for diagnosing the failure of the third fuel shutoff valve were needed.

The present invention has been made in view of the above circumstances, and an object of the present invention is to close and control the first fuel shutoff valve and the second fuel shutoff valve when both the ignition key signal and the driving state of the fuel pump are turned off. Based on the first fuel pressure of the fuel supply line when the first predetermined time elapses and the second fuel pressure of the fuel supply line when the second predetermined time elapses after closing control of the third fuel shutoff valve By accurately diagnosing a failure of the third fuel shutoff valve, an apparatus and method for diagnosing a failure of the fuel supply device of an Elpia vehicle which can prevent abnormal high pressure of the fuel supply line caused by the failure of the third fuel shutoff valve in advance. To be.

Technical problem according to the first aspect of the present invention for achieving the above object,

An LPI vehicle comprising a first fuel shutoff valve installed in a fuel supply line adjacent to a fuel tank, a second fuel shutoff valve installed in a fuel supply line adjacent to a gas injector and a third fuel shutoff valve installed in a fuel return line. In the failure diagnosis device of the fuel supply device,

When the start key signal supplied from the outside is turned off and the driving signal of the fuel pump is turned off, the first fuel cutoff valve and the second fuel cutoff valve are controlled after the first predetermined time elapses after the closing control of the first fuel cutoff valve and the second fuel cutoff valve. Failure of the third fuel shutoff valve based on the second fuel pressure of the fuel supply line measured when a second predetermined time elapses after the first fuel pressure of the fuel supply line and the third fuel shutoff valve are closed control. Characterized in that it includes a sub-YU to diagnose,

The sub-EC may increase a diagnostic counter when the second fuel pressure is greater than a difference between the first fuel pressure and a preset reference value, and generate an error code when the counting count of the diagnostic counter is greater than or equal to a predetermined number of times. Storing the counting count of the counter and error code generation.

Technical problem according to another aspect of the present invention,

An LPI vehicle comprising a first fuel shutoff valve installed in a fuel supply line adjacent to a fuel tank, a second fuel shutoff valve installed in a fuel supply line adjacent to a gas injector and a third fuel shutoff valve installed in a fuel return line. In the failure diagnosis method of the fuel supply device,

a) determining whether the received start key signal and the fuel pump drive signal are in an off state after receiving the start key signal received from the sub-EC oil and the drive signal of the fuel pump;

b) when the start key signal and the driving signal of the fuel pump are in the off state as a result of the determination in the step a), the first and second fuel cutoff valves installed in the fuel supply line are closed and controlled; Determining whether a predetermined time has passed and measuring a second fuel pressure of the fuel supply line when the first predetermined time has passed;

c) determining whether a second predetermined time has elapsed after controlling the closing of the third fuel shutoff valve and measuring the second fuel pressure of the fuel supply line when the second predetermined time elapses as a result of the determination; ;

d) comparing the second fuel pressure with a difference between the first fuel pressure of step c) and a preset reference value and increasing a diagnostic counter when the second fuel pressure is greater than the difference pressure as a result of the comparison; And

e) determining whether the number of counts of the diagnostic counter increased through step d) is greater than or equal to a predetermined number of times, generating an error code if the count is greater than or equal to a predetermined number, and storing the counting number and error code generation of the diagnostic counter; Characterized in that it comprises a.

B),

b-1) When the start key signal and the fuel pump driving signal are turned off as a result of the determination in step a), the first and second fuel cut-offs installed in the fuel supply line under the control of the sub-IC oil are cut off. Closing the valve;

b-2) determining whether a predetermined first predetermined time has elapsed through the sub IC; And

b-3) measuring a first fuel pressure of the fuel supply line when the first predetermined time set in step b-2) has elapsed,

C),

c-1) closing the third fuel shutoff valve;

c-2) determining whether a second predetermined time has elapsed through the sub-SI; And

c-3) measuring the second fuel pressure of the fuel supply line when the second predetermined time elapses as a result of the determination of step c-2).

According to the present invention, the fuel supply line measured when the first predetermined time elapses after closing the first fuel shutoff valve and the second fuel shutoff valve when both the ignition key signal and the driving state of the fuel pump are turned off. Accurately diagnose the failure of the third fuel shutoff valve based on the second fuel pressure of the fuel supply line measured when the second predetermined time elapses after the first fuel pressure and the third fuel shutoff valve are controlled to be closed. It becomes possible. Therefore, it is possible to prevent abnormally high pressure of the fuel supply line caused by the failure of the third fuel shutoff valve.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention. However, a vehicle employing the LPI system of the present invention will be described as an example.

Figure 2 is a block diagram showing the configuration of the fuel supply device of the Elpia vehicle according to the present invention, Figure 3 is a waveform diagram showing the fuel pressure of the fuel supply line of Figure 2, Figure 4 is a sub-IC shown in Figure 1 A flowchart illustrating a process of diagnosing a failure of the third fuel shutoff valve according to the significant control. 2 to 4, the fuel supply apparatus of the present invention includes a fuel tank 11, a fuel pump 13, a gas injector 17, a fuel supply line 21, a fuel return line 22, and a fuel. The first fuel shutoff valve SV1 includes a pressure sensor 23, a regulator 25, and a sub-ISO oil 33, and is installed at a position adjacent to the fuel fuel tank 11 in the fuel supply line 21. And a second fuel shutoff valve SV2 installed at a position adjacent to the gas injector 17 and a third fuel shutoff valve SV3 installed at the fuel return line 22.

The first fuel cutoff valve SV1 and the second fuel cutoff valve SV2 are controlled to be opened when the ignition key is turned on to supply the fuel discharged by the fuel pump 13 to the gas injector through the fuel supply line. It is provided to be closed control when the start key off, the third fuel shutoff valve SV3 is provided to be closed control to maintain the fuel pressure of the fuel supply line when the start key signal is off.

The sub-EC oil 33 generates a drive signal for driving the fuel pump 13 according to a start key signal supplied from the outside, and the fuel pump 13 is driven according to the drive signal, so that the fuel pump 13 The fuel in the fuel tank 11 discharged through the gas injector 17 passes through the first fuel shutoff valve SV1 and the second fuel shutoff valve SV2 of the fuel supply line 21 that is controlled to be opened. Is supplied.

That is, when the start key is on, the sub oil 33 controls the driving signal of the fuel pump and the first fuel shutoff valve SV1 and the second fuel shutoff valve SV2 in the open state. According to the generated control signal, the first fuel shutoff valve SV1 and the second fuel shutoff valve SV2 are controlled to an open state, and the fuel in the fuel tank 11 is driven by driving of the fuel pump 13. Is discharged in a liquefied state.

In this case, the third fuel shutoff valve SV3 is closed-controlled according to the control of the sub-EC oil 33, and the first fuel shutoff valve SV1 is open-controlled, and when the predetermined time elapses, 2 The fuel shutoff valve SV2 is open controlled. Here, the predetermined time is set to 100 msec as an optimal result obtained through a number of experiments. That is, the third fuel shutoff valve SV3 is closed and controlled under the control of the sub-C oil 33 so that the pressure of the fuel supply line 21 is maintained at a high pressure.

In addition, the gas injector 17 is a cylinder (in the liquid state of the LPG discharged from the fuel tank 11 through the fuel supply line 21 in accordance with the gas injection signal supplied from the sub-EC oil 33). (Not shown).

Thereafter, when the driving of the fuel pump 13 is stopped, the first fuel shutoff valve SV1 and the second fuel shutoff valve SV2 are controlled to be closed under the control of the sub-EC oil 33.

In this case, the sub ISO 33 is provided to receive the first fuel pressure of the fuel supply line 21 measured through the fuel pressure sensor 23 after a first predetermined time elapses, and then the sub ISO The oil 33 is the second fuel of the fuel supply line 21 measured by the fuel pressure sensor 23 when the second predetermined time elapses after the third fuel shutoff valve SV3 is closed controlled. It is provided to receive the pressure. Here, the first predetermined time is generally set to 2.5 seconds when the predetermined time is about 3 seconds, and the second predetermined time is set to 0.4 seconds when the predetermined time is 3 seconds. The first and second predetermined times are set to optimal values through a number of experiments.

In addition, the sub-EC oil 33 is provided to perform failure diagnosis of the third fuel shutoff valve SV3 based on the first fuel pressure and the second fuel pressure. The first fuel pressure and the second fuel pressure are as shown in FIG. 3.

That is, the sub-EC oil 33 compares the second fuel pressure shown in FIG. 3 with a difference between the first fuel pressure and a preset reference value, and when the second fuel pressure is greater than the difference pressure as a result of the comparison, a diagnosis counter. And generating an error code when the counting count of the diagnostic counter is increased to a predetermined number or more, and storing the counting count and the error code of the diagnostic counter. The reference value is set to 3 bar as a threshold value set through a number of experiments, and the predetermined time is set to five times.

In the failure diagnosis apparatus of the third fuel cutoff valve of the fuel supply device of the ELPIIA vehicle provided according to the present invention, the sub-EC oil 33 is a start key signal and a fuel pump 13 supplied from the outside. Receive the drive signal of (step 101), it is determined whether the start key signal and the drive signal of the fuel pump is Off (step 103).

When the start key signal and the driving signal of the fuel pump are turned off through the step 103, the sub-EC oil 33 is configured to supply the first fuel cutoff valve SV1 and the second fuel cutoff valve SV2. Control to close (step 105).

Through the above step 105, the sub-ECU 33 determines whether the first predetermined time has elapsed (step 107), and the fuel pressure sensor 23 when the first predetermined time has elapsed. Receive the first fuel pressure of the fuel supply line 21 measured through (step 109).

Subsequently, the sub-ECU 33 determines whether the second predetermined time has elapsed (step 113) after the third fuel shutoff valve SV3 is closed-controlled (step 111). When time elapses, the second fuel pressure of the fuel supply line 21 measured through the fuel pressure sensor 23 is received (step 115).

At this time, the sub-EC oil 33 compares the second fuel pressure with the difference between the first fuel pressure and the reference value (step 117), and as a result of comparison, the second fuel pressure is larger than the difference fuel pressure. If so, the diagnostic counter is incremented (step 119).

The sub IC 33 compares the counting value of the incremented diagnostic counter with a preset predetermined time (step 121), and generates an error code if the counting value of the diagnostic counter is greater than or equal to the predetermined time (step 121). 123) Store the counting number and error code occurrence of the diagnostic counter above (step 125).

When the second fuel pressure is less than the differential fuel pressure as a result of the comparison of the step 117, the third fuel shutoff valve SV3 is determined to be normal, and then the program is terminated.

As described above in detail, the apparatus and method for diagnosing a failure of the fuel supply device of an Elpia vehicle according to the present invention includes the first fuel cutoff valve and the second fuel shutoff valve when the start key signal and the driving state of the fuel pump are both off. Fuel supply measured when the first fuel pressure of the fuel supply line measured when the first predetermined time elapses after closing the fuel shutoff valve and when the second predetermined time elapses after closing the third fuel shutoff valve By accurately diagnosing the failure of the third fuel shutoff valve on the basis of the second fuel pressure of the line, it is possible to prevent the abnormal high pressure of the fuel supply line caused by the failure of the third fuel shutoff valve in advance.

What has been described above is only one embodiment for implementing a failure diagnosis apparatus and method of the vehicle fuel supply device according to the present invention, the present invention is not limited to the above-described embodiment, the claims below As claimed in the present invention, those skilled in the art to which the present invention pertains will have the technical spirit of the present invention to the extent that various changes can be made without departing from the gist of the present invention.

Claims (11)

An LPI vehicle comprising a first fuel shutoff valve installed in a fuel supply line adjacent to a fuel tank, a second fuel shutoff valve installed in a fuel supply line adjacent to a gas injector and a third fuel shutoff valve installed in a fuel return line. In the failure diagnosis device of the fuel supply device, When the start key signal supplied from the outside is off and the fuel pump is in the off state, the fuel supply line measured when the first predetermined time elapses after the first fuel shutoff valve and the second fuel shutoff valve are closed controlled. A sub-diagnostic of the failure of the third fuel shutoff valve based on the second fuel pressure of the fuel supply line measured when a second predetermined time elapses after the first fuel pressure and the third fuel shutoff valve are controlled to be closed. Include oil, The sub-EC may increase a diagnostic counter when the second fuel pressure is greater than a differential pressure between the first fuel pressure and a preset reference value, and generate an error code when the counting count of the diagnostic counter is greater than or equal to a predetermined time. And a counting number of the diagnostic counter and an error code generation. delete The fault diagnosis apparatus of claim 1, wherein the first predetermined time is 2.5 seconds. 4. The apparatus of claim 3, wherein the second predetermined time is 0.4 seconds. 4. The apparatus of claim 3, wherein the reference value is 3 bar. An LPI vehicle comprising a first fuel shutoff valve installed in a fuel supply line adjacent to a fuel tank, a second fuel shutoff valve installed in a fuel supply line adjacent to a gas injector and a third fuel shutoff valve installed in a fuel return line. In the failure diagnosis method of the fuel supply device a) determining whether the received start key signal and the fuel pump drive signal are in an off state after receiving the start key signal received from the sub-EC oil and the drive signal of the fuel pump; b) when the start key signal and the driving signal of the fuel pump are in the off state as a result of the determination in the step a), the first and second fuel cutoff valves installed in the fuel supply line are closed and controlled; Determining whether a predetermined time has passed and measuring a second fuel pressure of the fuel supply line when the first predetermined time has passed; c) determining whether a second predetermined time has elapsed after controlling the closing of the third fuel shutoff valve and measuring the second fuel pressure of the fuel supply line when the second predetermined time elapses as a result of the determination; ; d) comparing the second fuel pressure with a difference between the first fuel pressure of step c) and a preset reference value and increasing a diagnostic counter when the second fuel pressure is greater than the difference pressure as a result of the comparison; And e) determining whether the number of counts of the diagnostic counter increased through step d) is greater than or equal to a predetermined number of times, generating an error code if the count is greater than or equal to a predetermined number, and storing the counting number and error code of the diagnostic counter. Method for diagnosing a failure of the fuel supply device of the vehicle Elpia comprising a. The method of claim 6, wherein b), b-1) closing the first and second fuel shutoff valves on which the fuel supply line is installed when the start key signal and the driving signal of the fuel pump are turned off as determined in the step a); b-2) determining whether a predetermined first predetermined time has elapsed through the sub IC; And and b-3) measuring a first fuel pressure of the fuel supply line when the first predetermined time elapsed in the step b-2). Diagnostic method. The method of claim 7, wherein c) is c-1) closing the third fuel shutoff valve; c-2) determining whether a second predetermined time has elapsed through the sub-SI; And c-3) measuring a second fuel pressure of the fuel supply line when the second predetermined time elapses as a result of the determination of step c-2). How to diagnose faults. The method of any one of claims 6 and 8, wherein the first predetermined time is 2.5 seconds. 10. The method of claim 9, wherein the second predetermined time is 0.4 seconds. The fault diagnosis method of claim 10, wherein the reference value is 3 bar.

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