KR20120090212A - Apparatus and method for controlling fuel feed of automobile using both gasoline and lpg - Google Patents

Abstract

PURPOSE: A fuel supply control apparatus for vehicles with both gasoline and LPG and a control method thereof are provided to properly maintain a level of liquid fuels in a bomb by directly collecting the fuels from a low pressure part to the bomb. CONSTITUTION: A fuel supply control apparatus for vehicles with both gasoline and LPG comprises a LPG supply unit(20). The LPG supply unit comprises a LPG supply line(LS), a LPG recovery line(LR), a pressure regulator(25), a bypass line(B), and a first shutoff valve(27). The LPG supply line supplies LPG fuels in a bomb to a high pressure pump(30). The LPG recovery line recovers the some LPG supplied to the high pressure pump to the bomb. The pressure regulator reduces the pressure of the LPG fuels recovered to the bomb. The bypass line bypasses the fuels having vapor to the bomb. The first shutoff valve is opened and closed to bypass the fuels having vapor to the bomb when restarting an engine.

Description

Fuel supply control device and control method for gasoline and LPI combined vehicle {APPARATUS AND METHOD FOR CONTROLLING FUEL FEED OF AUTOMOBILE USING BOTH GASOLINE AND LPG}

The present invention relates to a fuel supply control device and a control method of a vehicle combined with gasoline and liquefied petroleum gas (hereinafter referred to as 'Elphi'), and more specifically, by using a single high-pressure pump to control gasoline and LPG fuel. The present invention relates to a fuel supply control device and a control method for a gasoline and LPG combined vehicle that pressurizes the engine at high pressure and directly sprays the engine to improve the power performance of the vehicle, reduce fuel consumption, and reduce the amount of carbon generated.

In general, among the fuels used in the vehicle, the LLP fuel is used in some passenger cars and vans because it has the advantage of high octane number, excellent heat resistance, and low fuel cost, and is expected to be applied to large vehicles.

The LPG fuel supplied to the engine of the vehicle is liquid and vaporizes because it has a good mixing property with air so that flammability is less likely to occur compared to gasoline and diesel, and knock-off or vaporization (Vapor-Lock) or percolation (Percolation) and the like. Since the same phenomenon can be prevented, its application range is gradually increasing as an alternative fuel of gasoline or diesel fuel.

Therefore, gasoline and elpgi combined vehicles have an electronic control unit that controls gasoline fuel tanks, vaporizers and mixers, elbow fuel tanks, solenoid valves and solenoid valves that control the supply of Elpig fuel. ) Is essentially provided.

Recently, in order to improve the engine output and reduce the emission of pollutants, the direct injection gasoline engine that injects and compresses only air into the engine and injects gasoline fuel and the liquefaction that directly injects liquid LPG fuel into the engine. Elpiai engines have been developed using the Liquefied Petroleum Injection (hereinafter referred to as Elpiai) engine.

Therefore, in order to simultaneously achieve two objectives of increasing environmental protection and fuel economy, the development of fuel supply control apparatus for a gasoline and LPG combined vehicle using a direct injection method is in progress.

An example of a technology for controlling fuel supply of a gasoline and LPG combined vehicle using the direct injection method is disclosed in Korean Patent Registration No. 10-0770802 (registered on October 22, 2007, hereinafter referred to as 'Patent Document 1'). have.

1 is a block diagram of an Elpia-type Elpig supply device according to Patent Literature 1 and the combined Elpig gasoline vehicle using the same.

As shown in FIG. 1, the LLP gasoline combined vehicle according to Patent Literature 1 is provided with a gasoline supply system 1 for supplying gasoline fuel to an engine and an LPI supply system 2 for supplying Elpgi fuel at the same time.

The gasoline supply system 1 includes a gasoline injector 3 mounted on a gasoline tank, a gasoline pump, a filter, a back pressure regulator and an intake pipe of an intake manifold.

The LLP supply system 2 includes an LLP tank 4 in which LLP fuel is stored, an LLP pump 5 for forcibly feeding LLP fuel, and an ELPI type fuel supply device 6.

The ELPI type fuel supply device 6 is a housing 6b in which the liquid LLP fuel is supplied through the supply pipe S and the supply pipe S connected to the LLP pump 5, and the LPI injector 6a is built therein. It includes a tube (6c) drawn out from (6b) and penetrated into the intake pipe (7) of the intake manifold, and a recovery pipe (R) for connecting the housing (6b) and the elbow tank (4).

The ELPI type fuel supply device 6 having such a configuration sucks the liquid LLP fuel, which is pumped into the housing 6b through the supply pipe R, from the LLP injector 6a through the tube 6c as it is in the liquid state. It moves to the engine 7 and injects into the intake valve front end of the combustion chamber 8.

At this time, the surplus of the LLP fuel remaining in the housing 6b is recovered to the LLP tank 4 through the recovery pipe (R).

Accordingly, the ELPI type fuel supply device of the LPG gasoline combined vehicle according to Patent Literature 1 is in a liquid state at the same position as the gasoline injection point of the gasoline injector 3 separately from the gasoline injector 3 mounted on the gasoline vehicle. Stable transfer and injection of LPG fuel.

That is, a gasoline and an LPG combined vehicle according to the prior art, such as an LPG gas combined vehicle including an LPIA fuel supply device according to Patent Literature 1, have a gasoline injector 3, an LPG injector 6a, and an LPG injector 6a embedded therein. And a gasoline supply system 1 and an LLP supply system 2 for supplying fuel to each injector 3 and 6a, respectively.

Accordingly, the combined gasoline and LPG vehicle according to the prior art has a problem that the configuration of the fuel supply device is complicated and the manufacturing cost increases.

If a single injector is used to inject gasoline fuel and LLP fuel, the injector prevents mixing of fuels having different fuel characteristics, and recovers each fuel remaining in the housing after fuel injection. There is a need to develop a technology for preventing the error to be returned to the tank.

When the engine is stopped after the vehicle is driven in the Elphi mode, the liquid phase of the liquid Elpig fuel remaining in the high pressure pump is vaporized by the remaining heat of the engine, thereby forming an air layer as bubbles are generated.

When the LLP fuel including bubbles from the air layer formed as described above is transferred to the pressure regulator through the LLP recovery line, there is a problem in that the time taken to pressurize the fuel to a preset pressure is increased.

In addition, there is a problem that cavitation occurs as the thermal equilibrium inside the bomb is broken as the Elpji fuel containing the bubble is recovered to the bomb.

Korea Patent Registration No. 10-0770802 (registered October 22, 2007)

The present invention is to solve the problems as described above, an object of the present invention is to provide a fuel supply control device and a control method for a gasoline and Elpgi combined vehicle directly injecting fuel into the engine of the gasoline and Elpgi combined vehicle. .

It is another object of the present invention to provide a fuel supply control apparatus and control method for a gasoline and elpgi combined vehicle that directly injects gasoline fuel and elpig fuel into an engine by mixing one injector.

Still another object of the present invention is to provide a fuel supply control apparatus and control method for a combined gasoline and elpgi vehicle, which prevents mixing of gasoline fuel supplied with a high pressure pump and elpji fuel, and recovers the surplus of the lpage fuel into the lpgi fuel tank. will be.

Still another object of the present invention is a fuel supply control device for a gasoline and LPG combined vehicle that improves initial start-up by preferentially bypassing fuel containing bubbles generated in the low pressure portion of the high-pressure pump when the engine is stopped after driving the LPI mode. And to provide a control method.

According to a feature of the present invention for achieving the object as described above, the present invention provides a high-pressure pump for pressurizing the gasoline fuel supplied from the gasoline supply unit, the LPG supply unit, gasoline supply unit or the LPG fuel supplied from the LPG supply unit to a predetermined pressure. In the fuel supply control device for a gasoline LPG combined vehicle provided, the LLP supply unit for recovering a part of the LLP fuel supplied to the high pressure pump, the LLP supply line for supplying the LLP fuel stored in the cylinder to the cylinder An elbow pump recovery line, a pressure regulator installed on the pump, and a pressure regulator for reducing the pressure of the LP pump fuel recovered from the low pressure part of the high pressure pump to the cylinder, and branched from the engine pump and restarted by the engine heat when the engine restarts. Low pressure part of high pressure pump Elbow oil fuel containing bubbles filled in the high-pressure pump is installed on the bypass line and the bypass line connected to the cylinder to bypass the fuel including the bubble filled in the cylinder to the cylinder And a first shutdown valve which opens and closes to bypass the furnace.

The LLP supply unit further includes a second shutdown valve installed on the LLP supply line to selectively block the LLP fuel and a third shutdown valve that selectively blocks the LLP fuel recovered through the LLP recovery line from the high pressure pump. The gasoline supply unit may include a fourth shutdown valve installed on the gasoline supply line to selectively block gasoline fuel.

The present invention provides a mode switch for selecting a gasoline mode for driving an engine by supplying a gasoline fuel and an Elpji mode for driving an engine by supplying an lpgi fuel, and the first to fourth shutdown valves based on a setting state of the mode switch. An electronic control unit for generating a control signal for controlling the opening and closing and a controller for controlling the opening and closing operations of the first to fourth shut-up valves based on the control signal, wherein the electronic control unit is the LPG in the gasoline mode When the mode switch is operated to switch to a mode, a control signal is generated to shut off the second shutdown valve and to open the third and fourth shutdown valves when a predetermined delay time elapses.

According to another feature of the present invention, the present invention is a fuel supply control method for a gasoline and Elpgi combined vehicle for supplying the gasoline fuel and the Elpgi fuel directly to the combustion chamber of the engine, (a) the Elpji mode for supplying the Elpgi fuel Stopping the engine after driving to the engine; (b) restarting the engine in a state of being set in the Elphi mode; and (c) through a bypass line provided between a high pressure pump and a cylinder for pressurizing the Elpji fuel to a high pressure. Performing bypass of the LLP fuel including bubbles filled in the high-pressure pump; and (d) the bypass line after a predetermined time has elapsed after performing the bypass through the bypass line in step (c). And closing the bypass line by closing the first shutdown valve to close and close the bypass line.

The present invention (e) when the gas is switched to the gasoline mode during the Elpji mode, after the predetermined delay time elapses after the gasoline supply line for supplying the gasoline fuel to the high-pressure pump to the high-pressure pump to the Elpji fuel The step of opening the LLP supply line for supplying (F) and the step of opening the LLP recovery line for recovering a part of the LLP fuel supplied to the high-pressure pump to the bomb, wherein the LLP supply line and the LLP recovery The line is characterized in that the opening and closing at the same time.

As described above, in the present invention, the present invention can selectively supply gasoline fuel and LLP fuel to a high pressure pump, and use a single injector to directly inject the fuel pressurized at high pressure into the engine.

Accordingly, the present invention can precisely control the injection amount of the gasoline fuel or the LPG fuel in the high-pressure liquid state to improve the power performance and fuel economy of the vehicle, and reduce the carbon generation amount.

In addition, the present invention can properly maintain the level of the liquid fuel in the cylinder by directly recovering fuel from the low pressure portion of the high pressure pump, and can suppress cavitation by preventing the empty space inside the cylinder from increasing rapidly.

In particular, the present invention can maintain the temperature of the fuel in a low temperature state by recovering the low-pressure Elpig fuel before supplying to the delivery pipe through a high pressure pump, thereby maintaining a constant temperature inside the cylinder, thermal equilibrium inside the cylinder Maintain state.

Accordingly, the present invention can perform the pressurized delivery process of the fuel smoothly to improve the performance of the LLP supply unit to the best.

In addition, the present invention, when switching from the gasoline mode to the Elpji mode, the second shut-off valve for opening and closing the gasoline fuel, after the predetermined delay time elapses, the third shutdown valve for supplying the Elpji fuel and the third recovery of the Elpji fuel 4 Open the shutdown valve.

Accordingly, the present invention has the effect of preventing the mixing of gasoline fuel and the LPG fuel in the high pressure pump, and precisely controlling the injection amount of the fuel injected into the combustion chamber of the engine to improve the performance of the engine.

In addition, the present invention is to open the first shut-up valve installed in the bypass line when restarting in the Elpji mode by preferentially bypassing the fuel containing bubbles filled in the low pressure portion of the high-pressure pump by the heat of the engine to the bomber in the pressure regulator It is possible to shorten the time taken to generate the pressure of the recovered Elpji fuel to a predetermined pressure.

Accordingly, the present invention has the effect of smoothly injecting the high-pressure liquid state of the liquid oil directly into the combustion chamber of the engine to improve the initial startability of the engine.

1 is a configuration diagram of an Elpia-type Elpgi supply device according to the prior art and the vehicle combined with the Elpig gasoline using the same.
2 is a block diagram of a fuel supply control apparatus for a gasoline and LPG combined vehicle according to a preferred embodiment of the present invention.
Figure 3 is a flow chart illustrating a step-by-step method of controlling the fuel supply of the combined vehicle gasoline support according to a preferred embodiment of the present invention.

Hereinafter, a fuel supply control apparatus and a control method for a gasoline and LPG combined vehicle according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram of a fuel supply control apparatus for a combined gasoline and LPG vehicle according to a preferred embodiment of the present invention.

In this embodiment, the fuel supplied through the gasoline supply line GS or the LPG supply line LS by the pumping operation of the gasoline pump 12 or the LPG pump 22 at the start of the engine is initially at a predetermined pressure, for example, about 2 bar. The pressure is delivered to the high pressure pump 30, the fuel pressure supplied at the beginning of the start is referred to as a 'low pressure state'.

In addition, the transfer path for transferring the low-pressure LPG fuel from the inlet of the high-pressure pump 30 to the LPG recovery line LR through the damper is referred to as a 'low pressure part'.

As shown in FIG. 2, a fuel supply control apparatus for a combined gasoline and LPG vehicle according to a preferred embodiment of the present invention includes a gasoline supply unit 10 and a cylinder 21 for supplying gasoline fuel stored in a gasoline tank 11. From the high-pressure pump 30, the high-pressure pump 30 to pressurize the pressure of the gasoline fuel or the LPG fuel supplied from the LLP supply unit 20, the gasoline supply unit 10 or the LPG supply unit 20 for supplying the stored LLP fuel The delivery pipe 40 in which the pressurized fuel is filled at high pressure and the fuel filled at high pressure in the delivery pipe 40 are directly injected into the combustion chamber of the engine based on the target RPM of the injector I and the engine E. And the gasoline pump 12 according to the control signal of the electronic control unit (ECU) 50 and the ECU 50 which generate control signals for controlling the driving of the injector I. ), Elfiji It includes a controller 60 for controlling the driving of the pump 22 and the injector (I), the LLP supply unit 20 is branched from the LLP recovery line (LR) and the rear end is connected to the bypass line (21) ( B) and a first shutdown valve 27 installed on the bypass line B.

The gasoline supply unit 10 includes a gasoline tank 11 in which gasoline fuel is stored, a gasoline pump 12 pumping gasoline fuel stored in the gasoline tank 11, and a gasoline fuel pumped from the gasoline pump 12 in a high pressure pump 30. And a second shutdown valve 13 installed on the gasoline supply line GS and gasoline supply line GS for selectively blocking gasoline fuel.

The second shutdown valve 13 opens the gasoline supply line GS to supply gasoline fuel according to a control signal of the ECU 50 transmitted through the controller 60 in the gasoline mode for supplying and driving gasoline fuel to the engine. do.

On the other hand, the second shut-up valve 13 closes the gasoline supply line GS to stop the supply of gasoline fuel in the Elphi mode, which is driven by supplying the engine with Elpji fuel.

The LPG supply unit 20 is installed in the cylinder 21 in which the LPG fuel is stored, and is installed in the cylinder 21 to selectively deliver fuel pumped by the LP pump 22 and the LP pump 23 to pump the LP fuel. A multi-valve (23), the agent is installed on the elbow supply line (LS), the elbow supply line (LS) for supplying the LPG fuel sent from the multi-valve 23 to the high-pressure pump (30) to selectively block the LPG fuel 3 Shut-up valve 24, the Elpji recovery line (LR) for recovering a portion of the Elpji fuel supplied to the high pressure pump 30 to the cylinder 21, the lpji recovery line (LR) is installed on the Fourth shut-off valve for selectively blocking the pressure of the Elpji fuel recovered from the low pressure portion to the cylinder 21 and the Elpji fuel recovered from the high-pressure pump 30 through the Elpji recovery line (LR) (26) is further included.

The first shut-up valve 27 is opened for a predetermined driving time when the engine E is started again in the stopped state after driving in the LLP mode to open the bypass line B, and closes when the driving time elapses. Operation to close the bypass line (B).

The present invention shortens the time it takes to generate the pressure of the LPG fuel recovered from the pressure regulator to the cylinder at a predetermined pressure by preferentially bypassing fuel containing bubbles filled in the low pressure portion of the high pressure pump when restarting in the LPG mode. can do.

Accordingly, the present invention smoothly injects the high-pressure liquid state of the liquid crystal oil directly into the combustion chamber of the engine to improve the initial startability of the engine.

As a result, the present invention directly injects a high-pressure liquid liquid LPG fuel into the engine, and recovers the remaining low-pressure fuel into the cylinder before supplying it to the engine, thereby reducing the power performance of the vehicle similarly to the direct injection of gasoline fuel. Improve fuel economy and reduce carbon emissions.

The third shut-up valve 24 opens the LLP supply line LR to supply the LLP fuel according to the control signal of the ECU 50 transmitted through the controller 60 in the LLP mode.

On the other hand, the third shut-up valve 24 closes the LLP supply line LR to stop the supply of the LLP fuel in the gasoline mode.

The pressure regulator 25 is a pre-pressurized pressure from the low pressure state (2bar) by the continuous pumping operation of the LLP pump 22, the pressure of the LLP fuel recovered from the low pressure portion of the high pressure pump 30 to the cylinder 21, for example When it is pressurized by Δ5 bar and becomes about 7 bar, an internal valve is opened to deliver the LPG fuel to the cylinder 21.

The pressure regulator 25 closes the valve when the pressure inside the cylinder is lower than about 7 bar as fuel is delivered to the cylinder 21 through the open valve, and then opens when the pressure inside the valve is higher than about 7 bar. Repeat the operation.

The pressurization pressure is a pressure set in advance to pressurize the fuel recovered to the cylinder 21 to achieve thermal equilibrium in the cylinder 21 to prevent vaporization.

Accordingly, in the cylinder 21, thermal equilibrium is achieved by the fuel discharged by the LLP pump 22 and the fuel recovered from the high pressure pump 30.

In detail, in the general Elpia system, fuel in the cylinder is discharged so that the fuel stored in the cylinder maintains the liquid state at the lower inner side, but vaporization occurs at the upper space, thereby lowering the saturated vapor pressure inside the cylinder.

As a result, the internal temperature of the bomb is drastically lowered, and fuel is more easily vaporized, and as the cavitation occurs during the first pumping process, the fuel delivery capacity of the LPG pump is significantly reduced.

On the other hand, in the present invention is to achieve a thermal equilibrium inside the bomb by recovering the appropriate amount of fuel through the LLP recovery line.

That is, the present invention can maintain the level of the liquid fuel in the cylinder properly by immediately recovering fuel from the low pressure portion of the high-pressure pump, and prevents a rapid increase in the empty space inside the cylinder, thereby cavitation (cavitation) ) Can be suppressed.

In particular, the present invention can maintain the temperature of the fuel in a low temperature state by recovering the low-pressure Elpig fuel before supplying to the delivery pipe through the high-pressure pump can maintain a constant temperature inside the bomb.

Accordingly, the inside of the cylinder 21 is to maintain the thermal equilibrium state. As such, when the thermal balance is made in the cylinder 21, the pressure sending process of the fuel may be performed smoothly, and thus the performance of the LLP supply unit 20 may be best exhibited.

In this case, the amount of fuel recovered may be controlled to an amount necessary for thermal balance through appropriate evaluation according to the size of the cylinder 21 and the vehicle displacement.

The fourth shut-up valve 26 recovers the Elpji to recover a portion of the Elpji fuel supplied to the high pressure pump 30 to the cylinder 21 according to the control signal of the ECU 50 transmitted through the controller 60 in the Elpji mode. Open the line LR.

On the other hand, the fourth shut-up valve 26 closes the LLP recovery line LR to stop the recovery of the LLP fuel in the gasoline mode.

The high pressure pump 30 is pumped by the gasoline pump or the LPG pump 22 to supply the gasoline fuel or a part of the LPG fuel supplied at a low pressure to a high pressure, for example, about 40 to 150 bar to supply the delivery pipe 40.

And the high pressure pump 30 is supplied to the injector (I) from the vellum fuel supplied to the delivery pipe 40 and to recover the excess lpgi fuel to the cylinder 11 through the lpgi recovery line (LR) from the internal low-pressure portion do.

Although the high-pressure pump 30 is not shown in the drawing, the pressurizing means for generating the suction force and the pressing force of the fuel therein, the damper portion for reducing the pulsation of the fuel, the flow rate of the fuel supply and the discharge of the fuel inlet is installed A spill valve for controlling pressure, an inlet check valve connected to the spill valve, and a discharge side check valve installed at a discharge port through which fuel is discharged.

On the other hand, the gasoline pump 12, the LPG 22 and the high pressure pump 30 is preferably provided as a volumetric pump using a piston, a diaphragm, gears, vanes and the like.

Impeller-type pumps, such as turbine pumps, have a positive pressurizing capacity in the pressurization process using two pumps, but gasoline pumps 12, LLP pumps 12 and high-pressure pumps 30 equipped with volumetric pumps pressurize fuel. This is because the effect of the pressurization capability multiplied by the pumping capability of the visual pumps 12, 22 and 30 can be exhibited.

According to the test result, the high pressure pump 30 is pumped by the LLP pump 22 to supply about 95% of the LLP fuel in the idle of the engine E among the fuel supplied to the high pressure pump 30. Through (LR) to recover to the cylinder 21, and during the normal operation of the engine (E) to recover about 60% of the fuel to the cylinder 21.

First and second pressure sensors for detecting the fuel pressure so as to check the moving fuel pressure in the front of the high-pressure pump 30 of the LP feed line (LS) and the rear of the high-pressure pump (30) of the LPG recovery line (LR) Not shown) is preferably installed, the delivery pipe 40 is preferably provided with a third pressure sensor (not shown).

The ECU 50 calculates the target RPM of the engine E, and selectively controls the gasoline supply unit 10 or the Elpji supply unit 20 to supply the gasoline fuel or the LLP fuel according to the calculated RPM.

To this end, the ECU 50 enters the gasoline mode or the LPG mode according to an operation of a mode switch (not shown) or a pre-programmed fuel supply method to selectively drive the gasoline supply unit 10 or the LPG supply unit 20. Control the supply of the fuel.

 For example, when the mode switch is set to the gasoline mode, or when the vehicle is started in the automatic mode or at high speed, the ECU 50 enters the gasoline mode to drive the gasoline supply unit 10 to supply gasoline fuel to the engine E. To control.

On the other hand, when the mode switch is set to the Elpji mode or the low-speed driving in the automatic mode state, the ECU 50 enters the Elpji mode and controls the Elpji fuel supply to the engine by driving the Elpig supply unit 20.

In this case, when the ECU 50 switches from the gasoline mode to the LPG mode, a predetermined delay time elapses after the second shut-off valve 13 is blocked in order to prevent the gasoline fuel and the LPG fuel from mixing in the high pressure pump 30. The third and fourth shutdown valves 24 and 26 are controlled to open.

The delay time is preferably set to less than about 0.5 seconds.

Meanwhile, the ECU 50 may set a delay time even when switching from the LPG mode to the gasoline mode. The ECU 50 blocks the third and fourth shutdown valves 24 and 26 without setting the delay time, and the second shutdown valve ( 13) may be controlled simultaneously to open.

According to the present invention, a gasoline fuel and an LPG fuel are selectively supplied to a high pressure pump, and a single injector is mixed to directly inject the fuel pressurized to a high pressure into the engine.

Accordingly, the present invention can precisely control the injection amount of the gasoline fuel or the LPG fuel in the high-pressure liquid state to improve the power performance and fuel economy of the vehicle, and reduce the carbon generation amount.

In addition, the ECU 50 generates a control signal and transmits the control signal to the controller 60 to open and close the first shutdown valve 27 for a preset driving time when the engine E is restarted after driving in the LLP mode.

The present invention maintains the thermal equilibrium of the bomb by first opening the first shut-up valve for a predetermined driving time when the engine is restarted after the engine stops in the Elphi mode by bypassing the LP gas including bubbles filled in the low pressure portion of the high-pressure pump to the cylinder. do.

Next, with reference to Figure 3 will be described in detail the fuel supply control method of a gasoline and LPG combined vehicle according to an embodiment of the present invention.

In the present embodiment, for convenience of description, a case of restarting after driving in the LPI mode will be described. However, the present invention is not necessarily limited thereto. That is, it should be noted that the same may be applied to restarting after switching to the LPG mode from the automatic mode in which the mode is changed according to the gasoline mode and the driving state of the vehicle of the present invention.

In the fuel supply control method of the combined gasoline and Elpgi vehicle according to the present embodiment, after driving in the Elpji mode, the ignition key is operated to stop the engine (S10), and then the ignition key (not shown) is operated to supply power. Will be started (S11).

The ECU 50 checks the setting state of the mode switch, and if the test result mode switch (not shown) is set to the Elpji mode, the ECU 50 enters the Elpji mode (S12).

On the other hand, when the engine E is stopped after driving the vehicle, the air layer is formed by vaporizing liquid LLP fuel in the low pressure part of the high-pressure pump 30 by the remaining heat of the engine E.

When the LLP fuel containing air bubbles is transferred from the air layer formed as described above to the pressure regulator 25 through the LLP recovery line LR, the time taken for the LLP fuel to pressurize the LLP fuel to a preset pressure is increased. do.

In addition, as the LLP fuel containing the bubble is recovered to the cylinder 21, the thermal equilibrium inside the cylinder 21 is broken and cavitation occurs.

In this embodiment, in order to solve such a problem, the first shutdown valve 27 is controlled to be opened for a preset driving time when the engine is restarted.

That is, the ECU 50 generates a control signal to open the first shutdown valve 27. Then, while the bypass line B is opened, the LLP fuel including bubbles filled in the low pressure portion of the high pressure pump 30 is preferentially bypassed to the cylinder 21 through the bypass line B (S13).

When the preset driving time elapses after opening the first shutdown valve 27 (S14), the ECU 50 generates a control signal to close the first shutdown valve 27. Then, the bypass line B is blocked and the bypass operation of the LLP fuel is stopped (S15).

The present invention by bypassing the Elpji fuel including the air bubbles filled in the high pressure pump when the engine restarts delayed opening and closing operation timing of the valve provided inside the pressure regulator is irregular in the amount of fuel to be recovered into the cylinder, recovery from the pressure regulator to the cylinder The time taken to generate the pressure of the fuel to be preset pressure is shortened.

Accordingly, the present invention can smoothly supply the high-pressure liquid state of the liquid oil to the engine at the start of the Elpiji mode can improve the initial startability of the engine.

Subsequently, the ECU 50 controls the LLP supply unit 10 to supply the LLP fuel to the engine E (S16).

In detail, the ECU 50 generates a control signal to open the third and fourth shutdown valves 24 and 26 and drive the LP pump 22 in a state in which the second shutdown valve 13 is shut off. .

Then, the controller 60 transmits the control signals transmitted from the ECU 50 to the second to fourth shutdown valves 13, 24, 26 and the LP pump 22 to control the third and fourth shutdown valves 24,. Open 26, and controls to drive the LLP pump 22 (S17).

Accordingly, the LLP fuel stored in the cylinder 21 is pumped by the LLP pump 22 and transferred to the high pressure pump 30 through the LLP supply line LS.

The high pressure pump 30 is driven using the driving force of the engine E in conjunction with the camshaft of the engine E, and a portion of the LLP fuel supplied through the third shutdown valve 24 is converted into high pressure, for example, about 40 to 150 bar. It is pressurized and supplied to the delivery pipe 40.

Accordingly, since the high pressure gasoline fuel is filled in the delivery pipe 40, the injector I is driven according to the control signal of the ECU 50 to directly inject gasoline fuel into the engine (S18). In addition, the engine is driven while the LPG fuel is combusted by the spark generated from the spark plug.

That is, according to the control signal of the ECU 50, the high pressure liquid oil is injected directly into the combustion chamber of the engine E in the injector I, so that the high pressure liquid oil is equal to the amount of fuel injected into the combustion chamber. The delivery pipe 40 is supplied.

Thus, the delivery pipe 40 always maintains a high pressure.

In addition, the ECU 50 may precisely control the injection amount of the high-pressure liquid LLP fuel injected into the combustion chamber of the engine E to improve the power performance and fuel economy of the vehicle and reduce the carbon generation amount.

In the step S18, the high-pressure pump 30 supplies the delivery pipe 40, and then delivers the surplus of the levitation fuel to the cylinder 21 from the low pressure portion through the lpage recovery line (LR).

At this time, as the valve inside the pressure regulator 25 is opened and closed, the fuel pressurized by about Δ5 bar, which is the pressurized pressure, is recovered to the cylinder 21 through the LLP recovery line LR (S19).

Accordingly, in the cylinder 21, thermal equilibrium is achieved between the Elpji fuel that is pumped and discharged by the Elpge pump 22 and the Elpji fuel that is pressurized and recovered by the pressure regulator 25.

On the other hand, according to the control signal of the ECU 50, as the high-pressure liquid state of the Elpji fuel is injected directly into the combustion chamber of the engine (E), the high-pressure high-molecular fuel as much as the amount of fuel injected into the combustion chamber is It is supplied to the delivery pipe 15.

As such, the delivery pipe 40 maintains a high pressure at all times, and thus, the elbow fuel in the delivery pipe 40 may be continuously maintained in a liquid state.

In addition, the ECU 50 precisely controls the injection amount of the high-pressure liquid Ellipse fuel injected into the combustion chamber of the engine E to improve the power performance and fuel economy of the vehicle, similar to the direct injection method of gasoline fuel, and the amount of carbon generated. Can be reduced.

On the other hand, when the test result mode switch of the step S11 is set to the gasoline mode, the ECU 50 controls to supply the gasoline fuel to the engine E by driving the gasoline supply unit 10 (S20).

In detail, the ECU 50 generates a control signal to open the second shut-off valve 13 and drive the gasoline pump 12 with the third and fourth shut-off valves 24 and 26 shut off. .

Then, the controller 60 transmits the control signal transmitted from the ECU 50 to the first to third shutdown valves 13, 24 and 26 and the gasoline pump 12 to open the second shutdown valve 13. Control to drive the gasoline pump 12 (S21).

Thus, the gasoline fuel stored in the gasoline tank 11 is pumped by the gasoline pump 12 and transferred to the high pressure pump 30 via the gasoline supply line GS.

The high pressure pump 30 pressurizes the gasoline fuel to a high pressure, for example, about 40 to 150 bar and supplies it to the delivery pipe 40.

Therefore, as the high-pressure gasoline fuel is filled in the delivery pipe 40, the injector I directly injects gasoline fuel into the combustion chamber of the engine E according to the control signal of the ECU 50, and then discharges the spark plug from the spark plug. The engine is driven while the gasoline fuel is burned by the generated flame (S22).

On the other hand, although not shown in the figure, if the mode switch is operated to switch to the gasoline mode during the Elpji mode according to steps S16 to S19, ECU 50 proceeds to step S20 to perform the gasoline mode To control.

Similarly, when the mode switch is operated to switch to the Elpji mode while performing the gasoline mode according to the steps S20 to S22, the ECU 50 proceeds to the step S16 to control to perform the Elpji mode.

At this time, the ECU 50 cuts off the second shutdown valve 13 and generates a control signal to open the third and fourth shutdown valves 24 and 26 after a predetermined delay time has elapsed. Prevent gasoline fuel and LPG fuel from mixing with each other.

Through the above process, the present invention preferentially provides fuel containing bubbles filled in the low pressure portion of the high-pressure pump by opening the first shut-off valve for a predetermined driving time when the engine is restarted after driving in the LPI mode. Passing reduces the time it takes to generate the pressure of the fuel returned to the cylinder from the pressure regulator to a preset pressure.

The scope of the present invention is not limited to the embodiments described above, but is defined by the claims, and various changes and modifications can be made by those skilled in the art within the scope of the claims. It is self evident.

10: gasoline supply unit 11: gasoline tank
12: gasoline pump 13: second shutdown valve
20: LPI supply 21: Bombe
22: LPG pump 23: multi-valve
24: third shutdown valve 25: pressure regulator
26: fourth shutdown valve 27: first shutdown valve
30: high pressure pump 40: delivery pipe
50: electronic control unit 60: controller
I: Injector B: Bypass Line
GS: Gasoline Supply Line LS: LPI Supply Line
LR: Elpig Recovery Line

Claims (5)

In the fuel supply control device for a gasoline LPG combined vehicle having a high-pressure pump for pressurizing the gasoline supply unit, the ellipse supply unit, the gasoline fuel supplied from the gasoline supply unit or the Elpiji fuel supplied from the ellipse supply unit to a predetermined pressure,
The LLP supply unit
An LPG supply line for supplying LPG fuel stored in a bomb to the high pressure pump;
An Elpji recovery line for recovering a part of the Elpgi fuel supplied to the high pressure pump to the bomb,
A pressure regulator installed on the LLP recovery line and reducing the pressure of the LLP fuel recovered from the low pressure part of the high pressure pump to the cylinder;
A bypass line branched from the LPI recovery line and connected to the bomb to bypass the fuel including bubbles filled in the low pressure portion of the high pressure pump by the heat of the engine when the engine is restarted;
Gasoline and LPG combined with a first shut-up valve installed on the bypass line to open and close the operation to bypass the LPG fuel containing bubbles filled in the high-pressure pump when the engine restarts. Vehicle fuel supply control device. The method of claim 1,
The LLP supply unit
A second shut-up valve installed on the LLP supply line and selectively blocking the LLP fuel;
Further comprising a third shutdown valve for selectively blocking the L-PGE fuel recovered from the high-pressure pump through the LLP recovery line,
The gasoline supply unit is installed on the gasoline supply line fuel supply control device for a gasoline and LPG combined vehicle, characterized in that it comprises a fourth shutdown valve for selectively blocking the gasoline fuel. The method of claim 2,
A mode switch for selecting a gasoline mode for supplying gasoline fuel to drive the engine and an Elpji mode for supplying the gasoline to drive the engine;
An electronic control unit for generating a control signal for controlling opening and closing of the first to fourth shutdown valves based on a setting state of the mode switch;
A controller for controlling the opening and closing operation of the first to fourth shutdown valve based on the control signal,
The electronic control unit, when the mode switch is operated to switch from the gasoline mode to the LPG mode, the control signal to shut off the second shutdown valve and open the third and fourth shutdown valve when a predetermined delay time has elapsed. Fuel supply control device for a combined gasoline and LPG vehicle, characterized in that to generate a. In the fuel supply control method for a gasoline and Elpgi combined vehicle for supplying the gasoline fuel and the Elpji fuel to be injected directly into the combustion chamber of the engine,
(a) stopping the engine after driving in an Elpji mode for supplying the Elpji fuel,
(b) restarting the engine in the state set to the LLP mode,
(c) performing a bypass of the LLP fuel including bubbles filled in the high pressure pump through a bypass line provided between the high pressure pump pressurizing the LLP fuel at a high pressure and a cylinder;
(d) closing the bypass line by closing a first shutdown valve for opening and closing the bypass line when a predetermined time elapses after performing bypass through the bypass line in step (c). Fuel supply control method of the combined gasoline and LPG vehicle comprising a. The method of claim 4, wherein
(e) when the gas is switched to the gasoline mode while the LPG mode is performed, supplying the LPG fuel to the high-pressure pump after a preset delay time after shutting off the gasoline supply line supplying the gasoline fuel to the high-pressure pump; Opening the LLP supply line and
(f) further comprising the step of opening an Elpji recovery line for recovering a portion of the Elpgi fuel supplied to the high pressure pump to the cylinder,
The fuel supply control method of the gasoline and LPG combined vehicle, characterized in that the LLP supply line and the LPG recovery line is opened and closed at the same time.

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