KR100746915B1 - ELPIA's fuel leakage prevention device and its control method - Google Patents

Abstract

LIQUEFIED PETROLEUM GAS INJECTION In order to prevent gas leakage from the injector, startability and exhaust gas reduction can be achieved.

Determining whether a start-off is detected in a state in which the engine is kept on; Detecting a pressure in the fuel line when the engine is turned off and determining whether the engine is above a predetermined reference value; In the method of preventing fuel leakage of an Elpia vehicle, the method comprising: opening and closing a solenoid valve disposed on a bypass line according to a pressure in a fuel line, thereby recovering fuel remaining in the fuel line. On the rear side, the first solenoid valve disposed in the fuel supply line and the second solenoid valve disposed in the fuel return line are closed, and the third solenoid valve disposed in the bypass line is opened to supply fuel remaining in the fuel line to the auxiliary fuel tank. In the process of recovering the remaining fuel in the fuel line to the auxiliary fuel tank, when the temperature and pressure of the fuel line are lower than the set value, the one-way check valve is opened for a predetermined time to discharge the recovered fuel into the fuel cylinder. It is characterized by.

ELPIAY Vehicle, Injector Leak, Fuel Recovery, Bay Pass Line, Solenoid Valve

Description

A FUEL LEAKAGE PREVENTION CONTROL SYSTEM OF LIQUIFIED PETROLEUM GAS INJECTION VEHICLE AND METHOD THEREOF}

1 is a block diagram of a fuel leakage prevention system of an Elpia vehicle according to the present invention.

2 is a flowchart of an embodiment in which an Elpia performs fuel leakage prevention control in a vehicle according to the present invention.

3 is a schematic configuration diagram of a typical ELPIA vehicle.

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

13: auxiliary fuel tank 14: check valve

22: first solenoid valve 33: second solenoid valve

100: bypass line 101: third solenoid valve

The present invention relates to a vehicle of LIQUEFIED PETROLEUM GAS INJECTION (hereinafter referred to as LPI), and more particularly, to prevent gas leakage from an injector, to improve startability and reduce exhaust gas of an ELPIAI vehicle. And a control method thereof.

For example, an LPI vehicle refers to a vehicle that adopts a fuel system in which a fuel pump is installed in a gas cylinder of an existing LPG vehicle to pump LPG in a liquid state to be injected from a gas injector. It is possible to solve the problems with the existing LPG vehicles.

As shown in FIG. 3, the LPI vehicle includes a fuel cylinder 10 for receiving and filling LPG fuel in a liquid state and a gas injector 50 mounted in a combustion chamber of the engine 40. 20 and the fuel return line 30.

The fuel supply line 20 has a fuel pump 11 for pressurizing and pumping the fuel in the fuel cylinder 10, the multi-valve 12 and the shut-off valve (downstream) of the fuel pump 11 21 are arranged sequentially.

The fuel return line 30 detects the pressure and temperature of the fuel applied to the gas injector 50 and the pressure regulator 31 for adjusting the pressure to approximately 5 to 15 bar in the liquid state to the gas injector 50. The fuel temperature / pressure sensor 32 is arranged.

The gas injector 50, the fuel pump 11, the multivalve 12, and the shut off valve 21 are electrically connected to and controlled by the controller 90 through the interface 80.

The fuel temperature / pressure sensor 32 is also electrically connected to the controller 90 through the interface 80 to supply information about the fuel to the controller 90.

In addition, the intake cylinder 60 has an intake air temperature sensor 61 for detecting the temperature of the air flowing into the combustion chamber, a throttle position sensor 63 for detecting the opening degree of the throttle valve which is linked to the accelerator pedal, and an idle speed actuator ( 62) and the like.

The exhaust system 70 is provided with an oxygen sensor 71, the engine 40 itself is a crank for detecting the angle of the crankshaft in the state in which the water temperature sensor 41 for detecting the temperature of the coolant and the engine 40 is operated. The position sensor 42 is provided.

Each component mounted on the intake system 60, the exhaust system 70, and the engine 40 is optimally supplied with information necessary for driving the engine to the controller 90 or controlled according to a control signal of the controller 90. The operation is made in the state.

In the conventional LPI vehicle, when the engine is turned off after the driving to the destination is completed, the temperature and the pressure of the fuel remaining in the fuel supply line and the fuel return line are rapidly increased by the temperature rise of the engine room.

Accordingly, the pressure in the gas injector-side fuel line gradually increases from +5 bar relative to the pressure of the fuel cylinder, mounted in the fuel pump, and rises to the relief valve operating pressure set at a pressure of about 10 bar.

Normally, the regulator is operated even after the engine is turned off, and the relief valve in the fuel pump causes it to flow back to the fuel pump when the fuel pressure rises above a certain pressure. When turned off, the fuel pressure rises rapidly, and the mechanical regulator and the relief valve alone cannot prevent fuel leakage.

In this case, fuel leakage occurs at the tip of the gas injector as the vehicle is bed-in, and thus fuel is too rich at start-up, which causes the start delay and the increase of HC emissions. It is implicated.

As described above, various methods have been proposed for solving a gas leak generated in a gas injector when the engine is turned off in the vehicle.

For example, a method of recovering fuel through a fuel return line when the engine is turned off by installing a recovery pump in the cylinder.

This method has to be equipped with a separate recovery pump in the cylinder, causing an increase in manufacturing cost, an algorithm for the control of the recovery pump should be set, and the disadvantage of causing an adverse effect on fuel economy by increasing the weight of the vehicle. have.

The present invention has been invented to solve the above problems, the object is to prevent the leakage of gas from the gas injector after the engine start stop so that the startability and exhaust gas reduction can be made.

That is, when the engine is turned off, the fuel return line connecting the gas injector and the fuel cylinder to the bypass line is connected to the fuel return line and the fuel cylinder to recover the fuel without a pressure regulator. will be.

The present invention for realizing the above object is an engine, a fuel pump is disposed and the fuel cylinder, LPG is filled, the gas injector, which is mounted to the engine and disposed between the fuel supply line and the fuel return line is connected to the fuel pump An Elpia vehicle comprising a multi-valve and a shut-off valve disposed in a fuel supply line, a pressure regulator disposed in the fuel return line, and a temperature / pressure sensor disposed in the fuel return line to detect fuel pressure and temperature.
A bypass line branched at a predetermined position of the fuel return line to directly connect a fuel cylinder and a fuel return line; A first solenoid valve disposed between the shutoff valve of the fuel supply line and a gas injector and operated by a control signal of a controller; A second solenoid valve disposed between the pressure regulator of the fuel return line and the fuel cylinder and operated by a control signal of a controller; And a control unit for recovering the remaining fuel existing in the fuel line to the fuel cylinder through the bypass line when the gradient of the pressure rise of the fuel line satisfies the fuel leakage condition of the gas injector when the engine is turned off.
An auxiliary fuel tank for temporarily storing the fuel recovered through the bypass line is disposed in the fuel cylinder, and a one-way check valve is disposed at a predetermined position on the lower side of the auxiliary fuel tank, and the one-way check valve is configured as a fuel line. The pressure is opened in a condition higher than the pressure in the fuel cylinder, characterized in that the discharged stored fuel is discharged into the fuel cylinder.
In addition, the present invention comprises the steps of determining whether the start-off is detected in the state that the engine maintains the starting on; Detecting a pressure in the fuel line when the engine is turned off and determining whether the engine is above a predetermined reference value; In the method of preventing fuel leakage of an Elpia vehicle comprising the process of recovering fuel remaining in the fuel line by opening and closing the solenoid valve disposed in the bypass line in accordance with the pressure in the fuel line,
When the pressure in the fuel line is equal to or greater than a predetermined reference value, the first solenoid valve disposed in the fuel supply line and the second solenoid valve disposed in the fuel return line are closed, and the third solenoid valve disposed in the bypass line is opened to open the fuel. When the fuel remaining in the line is recovered to the auxiliary fuel tank and the fuel remaining in the fuel line is recovered to the auxiliary fuel tank, when the temperature and pressure of the fuel line are lower than the set value, the one-way check valve is opened for a predetermined time. It is characterized by discharging the recovered fuel into the fuel cylinder.

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Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of an apparatus for preventing fuel leakage of an Elpia vehicle according to the present invention.

The same reference numerals are assigned to the same parts as those of the conventional configuration described above in the configuration of the fuel leakage preventing device of the vehicle according to the present invention.

As shown, the fuel cylinder 10 for receiving and filling the LPG fuel in a liquid state, and the gas injector 50 mounted in the combustion chamber of the engine 40, the fuel supply line 20 and the fuel return line ( 30).

The fuel supply line 20 has a fuel pump 11 for pressurizing and pumping the fuel in the fuel cylinder 10, the multi-valve 12 and the shut-off valve (downstream) of the fuel pump 11 21 is sequentially arranged, and a first solenoid valve 22 is mounted between the shutoff valve 21 and the gas injector 50.

The first solenoid valve 22 is operated by a control signal of the controller 90.

The fuel return line 30 detects the pressure and temperature of the fuel applied to the gas injector 50 and the pressure regulator 31 for adjusting the pressure to approximately 5 to 15 bar in the liquid state to the gas injector 50. The fuel temperature / pressure sensor 32 is arranged.

A second solenoid valve 33 is mounted at a predetermined position of the fuel return line 30, preferably a line connecting the pressure regulator 31 and the fuel cylinder 10, and the second solenoid valve 33 is It is operated by the control signal of the controller 90.

In addition, a bypass line 100 branched at a predetermined position of the fuel return line 30 and connected to the fuel cylinder 10 is installed, and the bypass line 100 is connected to a control signal of the controller 90. It is equipped with a third solenoid valve 101 which is operated by.

The fuel cylinder 10 is equipped with an auxiliary fuel tank 13 for temporarily storing the fuel recovered through the bypass line 100, and the one-way check valve at a predetermined position on the lower side of the auxiliary fuel tank 13 14) is mounted.

The auxiliary fuel tank 13 temporarily stores the gas injector 50 when the temperature of the fuel recovered through the bypass line 100 is increased by the temperature of the engine 40 after the engine 40 is stopped. Prevents gas leaks through the tip.

The one-way check valve 14 discharges the fuel recovered through the bypass line 100 into the fuel cylinder 10.

The gas injector 50, the fuel pump 11, the multivalve 12, and the shutoff valve 21 are electrically connected to and controlled by the controller 90 through the interface 80.

The fuel temperature / pressure sensor 32 is also electrically connected to the controller 90 through the interface 80 to supply information about the fuel to the controller 90.

In addition, the intake cylinder 60 has an intake air temperature sensor 61 for detecting the temperature of the air flowing into the combustion chamber, a throttle position sensor 63 for detecting the opening degree of the throttle valve which is linked to the accelerator pedal, and an idle speed actuator ( 62).

The exhaust system 70 is provided with an oxygen sensor 71, the engine 40 itself is a crank for detecting the angle of the crankshaft in the state in which the water temperature sensor 41 for detecting the temperature of the coolant and the engine 40 is operated. The position sensor 42 is provided.

Each component mounted on the intake system 60, the exhaust system 70, and the engine 40 is optimally supplied with information necessary for driving the engine to the controller 90 or controlled according to a control signal of the controller 90. The operation is made in the state.

In the present invention having the above-described configuration, an operation of preventing the fuel leakage from the gas injector during the start-off of the engine will be described with reference to FIG. 2.

Since the control of fuel injection in the Elpia vehicle according to the present invention is the same as or similar to the normal operation, a detailed description thereof will be omitted, and only the operation of the control for preventing fuel leakage in the gas injector according to the start-off of the engine will be described. do.

In a state where the engine 40 of the Elpia vehicle is kept on, the control unit 90 receives various control information through signals and interfaces 80 of various sensors mounted on the intake system 60 and the exhaust system 70. It reads (S101), and determines whether the starting-off of the engine 40 by detection of an ignition key is detected (S102).

If the start of the engine 40 is maintained in S102, the control of the current engine 40 is maintained. If the start stop of the engine 40 is detected by the controller 90 in S102, the control unit 90 receives the water temperature. The temperature of the cooling water is read from the sensor 41, and the intake air temperature flowing into the engine 40 from the intake air temperature sensor 61 is read (S103) to determine whether the temperature of the cooling water and the intake air temperature are kept above the set reference temperature. (S104).

As a result of the determination in S104, when the temperature of the cooling water and the intake temperature are lower than the set reference temperature, the temperature of the engine 40 does not affect the expansion of the gas pressure, and thus, fuel leakage prevention control of the gas injector 50 is not performed.

However, when the determination result of S104 indicates that the coolant temperature and the intake temperature are equal to or higher than the set reference temperature, the pressure of the fuel supply line 20 and the fuel return line 30 is read (S105), and then the pressure processing counter (Pn = Pn + Start 1) (S106).

Where n = 0, 1, 2,... , 120 (end).

When the pressure treatment counter is started as described above, the controller 90 calculates the pressure gradient of the fuel supply line 20 and the fuel return line 30 whenever the pressure treatment counter is increased (S107). It is determined whether the slope is detected to be equal to or greater than a reference value set in order to determine a possible fuel leakage condition of the gas injector 50 (S108).

If it is determined in S108 that the pressure gradient does not satisfy a fuel leakage possibility condition, the flow returns to S105 to perform a pressure processing counter.

However, if the pressure gradient calculated in the determination of S108 is equal to or greater than a set reference value that satisfies the fuel leakage possible condition, leakage prevention control of the gas injector 50 is started (S109).

Thereafter, the controller 90 closes and controls the first solenoid valve 22 mounted on the fuel supply line 20 and the second solenoid valve 33 mounted on the fuel return line 30 through the interface 80. In operation S110, the third solenoid valve 101 mounted on the bypass line 100 is controlled to be opened (S111).

Therefore, the gas injector 50 connected to the fuel supply line 20 is prevented from supplying fuel from the fuel cylinder 10, and the return of the fuel to the fuel cylinder 10 through the fuel return line 20 is performed. The remaining fuel present in the fuel line is recovered and stored in the auxiliary fuel tank 13 provided in the fuel cylinder 10 through the bypass line 100.

In the state of recovering the remaining fuel existing in the fuel line to the fuel cylinder 10 as described above, the controller 90 detects the fuel temperature and the pressure of the fuel return line 30 (S112), and maintains the set reference temperature or less. It is determined whether (S113).

Detecting and comparing the fuel temperature and pressure of the fuel return line 30 with the set reference temperature is less than the pressure in the fuel cylinder 10 through the one-way check valve 14 mounted to the lower portion of the auxiliary fuel tank 13 This is to discharge the recovered fuel to the fuel cylinder 10 when maintaining a high state.

If it is determined in S113 that the fuel temperature and the pressure of the fuel return line 30 are kept below the set reference temperature, the controller 90 is the one-way check valve 14 mounted below the auxiliary fuel tank 13. Open to discharge the fuel recovered in the auxiliary fuel tank 13 to the fuel cylinder 10 (S114).

At the same time, the controller 90 controls the first solenoid valve 22 mounted on the fuel supply line 20 and the second solenoid valve 33 mounted on the fuel return line 30 to switch to the open state (S115). In operation S116, the third solenoid valve 101 mounted on the bypass line 100 is controlled to be closed.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent embodiments are possible.

As described above, in the present invention, Elpia directly bypasses the fuel return line and the fuel cylinder in which the engine is turned off in the vehicle, so that a pressure rise in the fuel line does not occur, thereby preventing fuel leakage in the gas injector. Stability and reliability are provided for the operation of LPI vehicles.

Claims (9)

Fuel cylinder with LPG filling and engine, fuel pump mounted, gas injector mounted between engine and fuel return line, multi-valve and shutter-off arranged in fuel supply line connected with fuel pump An elpia vehicle comprising a valve, a pressure regulator disposed on the fuel return line, and a temperature / pressure sensor disposed on a fuel return line to detect fuel pressure and temperature. A bypass line branched at a predetermined position of the fuel return line to directly connect a fuel cylinder and a fuel return line; A first solenoid valve disposed between the shutoff valve of the fuel supply line and a gas injector and operated by a control signal of a controller; A second solenoid valve disposed between the pressure regulator of the fuel return line and the fuel cylinder and operated by a control signal of a controller; And a control unit for recovering the remaining fuel existing in the fuel line to the fuel cylinder through the bypass line when the gradient of the pressure rise of the fuel line satisfies the fuel leakage condition of the gas injector when the engine is turned off. The fuel cylinder is disposed in the auxiliary fuel tank for temporarily storing the fuel recovered through the bypass line, a one-way check valve is disposed at a predetermined position on the lower side of the auxiliary fuel tank, And the one-way check valve is opened in a condition where the pressure of the fuel line is higher than the pressure in the fuel cylinder to discharge the stored and stored fuel into the fuel cylinder. delete delete delete Determining whether a start-off is detected in a state in which the engine is kept on; Detecting a pressure in the fuel line when the engine is turned off and determining whether the engine is above a predetermined reference value; In the method of preventing fuel leakage of an Elpia vehicle comprising the process of recovering fuel remaining in the fuel line by opening and closing the solenoid valve disposed in the bypass line in accordance with the pressure in the fuel line, When the pressure in the fuel line is equal to or greater than a predetermined reference value, the first solenoid valve disposed in the fuel supply line and the second solenoid valve disposed in the fuel return line are closed, and the third solenoid valve disposed in the bypass line is opened to open the fuel. Recover fuel remaining in the line to the auxiliary fuel tank, In the process of recovering the remaining fuel in the fuel line to the auxiliary fuel tank when the temperature and pressure of the fuel line is less than the set value, the one-way check valve is opened for a predetermined time, characterized in that for discharging the recovered fuel into the fuel cylinder How to avoid fuel leaks delete delete delete delete

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