WO2018212415A1

WO2018212415A1 - Dual fuel direct-spray apparatus

Info

Publication number: WO2018212415A1
Application number: PCT/KR2017/012230
Authority: WO
Inventors: 김성훈
Original assignee: 김성훈
Priority date: 2017-05-15
Filing date: 2017-11-01
Publication date: 2018-11-22
Also published as: KR101938259B1; KR20180125193A

Abstract

The present invention relates to a dual fuel direct-spray apparatus, and to a dual fuel direct-spray apparatus for, when supplying dual fuels by switching therebetween, supplying a selected fuel to a high-pressure pump by using the same fuel conduit. For such purpose, a dual fuel direct-spray apparatus is disclosed which comprises: a liquefied fuel storage container for storing liquefied fuel; a liquid fuel storage container for storing liquid fuel; and a fuel supplying conduit for enabling the liquefied fuel and the liquid fuel to be supplied to a high-pressure pump via the same conduit.

Description

Different fuel direct injection device

The present invention relates to a hetero-fuel direct injection device, and more particularly, to a hetero-fuel direct injection device for supplying selected fuels to a high-pressure pump using the same fuel conduit in supplying heterogeneous fuels to each other.

Prior art (KR 10-1557904) discloses an apparatus and method for directly injecting two types of fuel for an internal combustion engine. According to the disclosed contents of the prior document there is a problem that a separate booster pump is required to equalize the pressure of the gasoline fuel at the beginning of the conversion of gasoline fuel in LPG fuel.

In addition, according to the disclosed contents of the prior document can not prevent the phase change occurring in the high-pressure pump, the purge fuel remains in the high-pressure pump, further purge fuel remaining in the conduit connecting the high-pressure pump and the fuel injection rail There is a problem that does not disclose a method that can be treated to cause a start-up mismatch (or error) when switching from LPG fuel to gasoline fuel.

Therefore, the present invention was created in order to solve the problems as described above, by supplying the conduit supplied to the high-pressure pump when supplying gasoline fuel and LPG fuel using a single conduit, so as not to use a booster pump, It is an object of the present invention to provide an invention in which a pump can be cooled to suppress generation of purge fuel, and conduits and valves capable of recovering purge fuel can be prevented from starting inconsistency.

However, the objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

The object of the present invention described above is to include a liquefied fuel reservoir for storing liquefied fuel, a liquid fuel reservoir for storing liquid fuel, and a fuel supply conduit for liquefied fuel and liquid fuel to be supplied to a high pressure pump through the same conduit. It can be achieved by providing a heterogeneous direct fuel injection feature.

The apparatus further includes a liquid fuel transfer conduit for transferring the liquid fuel in the liquid fuel reservoir to the liquid fuel confluence point of the fuel conduit of the liquefied fuel reservoir.

In addition, the liquid fuel supplied from the liquid fuel pump of the liquid fuel reservoir is supplied to the liquid fuel confluence point according to the on / off of the liquid fuel supply valve installed in the liquid fuel transfer conduit, so that the liquid fuel is supplied to the high pressure pump by the fuel supply conduit. .

In addition, the liquefied fuel pump of the liquefied fuel reservoir pumps the liquefied fuel and the liquid fuel to be supplied to the high pressure pump through the fuel supply conduit.

The apparatus may further include a cooling unit for cooling the high pressure pump by being installed in the peripheral region of the high pressure pump.

The apparatus further includes a refrigerant supply conduit branched at one point of the fuel supply conduit and supplying the refrigerant to the cooling unit.

In addition, the refrigerant is a liquefied fuel supplied from the liquefied fuel reservoir, the liquefied fuel is supplied to the cooling unit in accordance with the on / off of the refrigerant supply valve installed in the refrigerant supply conduit.

The apparatus may further include a refrigerant return conduit for returning the liquefied fuel used as the refrigerant in the cooling unit to the liquefied fuel reservoir.

The apparatus may further include a high pressure fuel supply conduit for supplying fuel from the high pressure pump to the fuel injection rail, and purge the gas generated by the phase change of the liquefied fuel remaining in the high pressure fuel supply conduit to transfer to the refrigerant return conduit.

The apparatus further includes a purge conduit connecting the high pressure fuel supply conduit and the refrigerant return conduit so that the purged gas is transferred to the refrigerant return conduit, wherein the gas purged by on / off of the purge fuel supply valve installed in the purge conduit is refrigerant. Conveyed to the return conduit.

In addition, the gas generated by the phase change of the liquefied fuel remaining in the low pressure portion of the high pressure pump is purged and transferred to the refrigerant return conduit.

The apparatus further includes a purge conduit connecting the low pressure portion of the high pressure pump and the refrigerant return conduit so that the purged gas is transferred to the refrigerant return conduit.

The apparatus may further include a controller for controlling at least one of a liquefied fuel supply mode, a liquid fuel supply mode, a fuel changeover mode, a flashing mode, and a start mode, wherein the fuel changeover mode for switching from liquefied fuel to liquid fuel is liquid. The liquefied fuel pump is turned on so that the fuel supply valve is turned ON, the liquefied fuel supply valve is turned OFF, and the supply pressure of the liquid fuel is at least equal to the pressure in the fuel supply conduit at the time of supply of the liquefied fuel. The pump is to be pumped at the beginning of the changeover, and the liquefied fuel pump is pumped to supply a pressure lower than the initial pressure of the mode changeover after a certain time.

The apparatus further includes a control unit for controlling at least one of a liquefied fuel supply mode, a liquid fuel supply mode, a fuel changeover mode, a flashing mode, and a start mode, wherein the flashing mode is a liquefied fuel supply mode that starts after the start is turned off. Before entering the mode, the purge fuel supply valve is turned on to purge the gas generated by the phase change of the liquefied fuel to the refrigerant return conduit, and the refrigerant supply valve is turned on to cool the high pressure pump.

According to the present invention as described above, by supplying the conduit supplied to the high pressure pump when supplying gasoline fuel and LPG fuel using one conduit, there is an effect that the booster pump is not used, and the high pressure pump is cooled to By suppressing the generation of the purge fuel, by disposing a conduit and a valve capable of recovering the purge fuel, there is an effect that can be prevented from starting disharmony.

The following drawings, which are attached to this specification, illustrate one preferred embodiment of the present invention, and together with the detailed description thereof, serve to further understand the technical spirit of the present invention. It should not be construed as limited.

1 is a view showing the configuration of a hetero fuel direct injection device according to a first embodiment of the present invention,

2 is a view showing the configuration of a hetero fuel direct injection device according to a second embodiment of the present invention,

3 is a view showing the operation of the valve and the pump in the short time mode over time,

4 is a view showing the operation of the valve and the pump in the long time mode over time.

Hereinafter, with reference to the drawings will be described a preferred embodiment of the present invention. In addition, one Example described below does not unduly limit the content of this invention described in the Claim, and the whole structure demonstrated by this Embodiment is not necessarily required as a solution of this invention. In addition, the matters obvious to those skilled in the art and the art may be omitted, and the description of the omitted elements (methods) and functions may be sufficiently referred to without departing from the spirit of the present invention.

Heterogeneous fuel direct injection device according to an embodiment of the present invention relates to a device for directly injecting a mixture of liquid fuel and liquefied fuel. That is, a device for directly injecting one selected fuel by selectively switching from liquid fuel to liquefied fuel or by selectively switching fuel from liquefied fuel to liquid fuel by control of a controller or manual selection of a user. In this case, the liquid fuel may be, for example, gasoline fuel (or gasoline) or diesel fuel, and the liquefied fuel may be LPG fuel. Hereinafter, for convenience of explanation, it will be described assuming that the liquid fuel as gasoline fuel, and liquefied fuel as LPG fuel.

<제 1 실시예><First Embodiment>

As shown in FIG. 1, the hetero fuel direct injection device according to the first embodiment of the present invention selectively supplies gasoline fuel and LPG fuel provided in each fuel reservoir to the high pressure pump 300, and the high pressure pump 300. Compresses the fuel in the) to supply to the fuel injection rail 400. LPG fuel is stored in the LPG fuel storage container 100, the gasoline fuel is stored in the gasoline fuel storage container 200. At this time, the prior art (KR 10-1557904, see Fig. 1) is a fuel supply to the high-pressure pump using the respective fuel conduit in each fuel reservoir, but in the present invention high pressure using the same fuel supply conduit 11 The fuel is supplied to the pump 300.

In more detail, a fuel conduit for transporting the LPG fuel stored in the LPG fuel storage container 100 is disposed from the LPG fuel storage container 100 to the high pressure pump 300. At this time, the fuel conduit is divided in more detail, the LPG fuel transfer conduit 18 for transporting only LPG fuel and the fuel supply conduit 11 for transporting any selected fuel of gasoline fuel or LPG fuel to the high pressure pump 300. Can be divided into LPG fuel transfer conduit 18 is shown in Figure 1 to the first branch point 21, from the first branch point 21 to the high-pressure pump 300 can be divided for convenience of description as a fuel supply conduit (11). . The LPG fuel supply valve 120 is disposed at one point of the LPG fuel transfer conduit 18 to turn on / off the supply of the LPG fuel. That is, when gasoline fuel is supplied to the first branch point 21, the LPG fuel supply valve 120 is turned off to block the transfer of the LPG fuel, and when the gasoline fuel is not supplied, the gas is turned on. LPG fuel is transferred to the fuel supply conduit (11). At this time, the LPG fuel supply valve 120 is cooperatively controlled by a control unit (not shown) together with the gasoline fuel supply valve 220 to be described later, optionally any one of the high pressure pump through the fuel supply conduit 11 ( 300).

Gasoline fuel storage tank 200 is stored gasoline fuel, the stored gasoline fuel is pumped by the gasoline fuel pump 210 is supplied. At this time, the gasoline fuel pump 210 supplies gasoline fuel at a pressure of 5 to 6 bar as an example. The pumped gasoline fuel is supplied to the first branch point 21 of the LPG fuel transfer conduit 18 through the liquid fuel transfer conduit 12. As such, the gasoline fuel is transferred to the first branch point 21 so that any fuel selectively selected from the first branch point 21 to the high pressure pump 300 is transferred through the same fuel conduit. The gasoline fuel supply valve 220 is disposed in the liquid fuel transfer conduit 12 and is turned on / off under the control of the controller to supply or shut off the gasoline fuel to the first branch point 21.

According to the on / off control of the LPG fuel supply valve 120 or the gasoline fuel supply valve 220, gasoline fuel or LPG fuel is transferred to the high pressure pump 300 from the first branch point 21. An LPG fuel supply valve 120 is disposed at an upstream side of the first branch point 21 at one point of the LPG fuel transfer conduit 18, and an LPG fuel pump 110 is disposed at a downstream side of the first branch point 21 at the fuel supply conduit. It is disposed at one point of 11. The LPG fuel pump 110 pumps LPG fuel and supplies LPG fuel to the high pressure pump 300, or pumps gasoline fuel joined to the first branch point 21 to pump gasoline fuel to the high pressure pump 300. do. At this time, the LPG fuel pump 110 pumps LPG fuel at a pressure of 10 bar as an example. When the fuel supply is converted from LPG fuel to gasoline fuel, approximately 10 bar of pressure remains in the fuel supply conduit 11 by the pumping of the LPG fuel before the conversion, and the pumping pressure of the gasoline fuel after the conversion is about 5 bar, resulting in a pressure imbalance. Occurs. Therefore, the LPG fuel pump 110 allows the gasoline fuel to be pumped at a pressure of approximately 10 bar at the initial stage after the switching, and then pumps the gasoline fuel at a pressure of 5 bar again after a predetermined time (after pressure equalization), thereby reducing the LPG fuel pressure at the initial stage of the fuel conversion. Equalize the pressure so that the same pressure is applied to the gasoline fuel. The selected fuel pumped by the LPG fuel pump 110 is transferred to the high pressure pump 300 side.

The fuel supply conduit 11 is a conduit for transferring the selected fuel from the first branch point 21 to the high pressure pump 300. A second branch point 22 is formed at one point of the fuel supply conduit 11. The second branch point 22 is a point where the LPG fuel supplied to the high pressure pump 300 and the LPG fuel transferred to the cooling unit 500 to be described later branch to each other when the LPG fuel is supplied. LPG fuel transferred to the cooling unit 500 is used as a refrigerant of the cooling unit 500. The refrigerant (or LPG fuel) branched at the second branch point 22 is supplied to the cooling unit 500 along the refrigerant supply conduit 13. The refrigerant supply conduit 13 transfers the refrigerant from the second branch point 22 to the cooling unit 500. A coolant supply valve 510 is disposed at one point of the coolant supply conduit 13 and is turned on / off under the control of a controller to supply or shut off the coolant.

The high pressure pump 300 compresses the supplied fuel at high pressure to supply fuel to the fuel injection rail 400 through the high pressure fuel supply conduit 14. The high pressure pump 300 may be divided into a low pressure part and a high pressure part (not shown) for convenience of explanation, the low pressure part is a side receiving fuel from a fuel reservoir, and the high pressure part is a side discharging fuel to the fuel injection rail 400. . A third branch point 23 is formed in the high pressure fuel supply conduit 14. The LPG fuel used as the refrigerant in the cooling unit 500 is recovered to the LPG fuel storage container 100 through the refrigerant return conduit 15. A fourth branch point 24 is formed at one point of the refrigerant return conduit 15. A first purge conduit 16 is disposed connecting the third branch point 23 and the fourth branch point 24. A purge fuel supply valve 610 is disposed at one point of the first purge conduit 16. The high pressure fuel discharged from the high pressure pump 300 is supplied to the fuel injection rail 400 so that the selected fuel is directly injected, and the purge fuel supply valve 610 is in an OFF state. If the finally selected fuel is used as LPG fuel and the engine is turned off and then started again after a certain time, gas (or purge fuel) generated by the phase change of the LPG fuel remains in the high pressure fuel supply conduit 14. Done. The presence of such purge fuel is one of the reasons for starting up when turning on starting up again. Therefore, in this case (i.e., when the start-up is turned on by the start mode again after the final start is turned off in the LPG fuel mode), the purge fuel supply valve 610 is turned on, thus remaining in the high-pressure fuel supply conduit 14. The purge fuel is preferably purged through the first purge conduit 16 to the refrigerant return conduit 15. Therefore, the purge fuel is purged from the third branch point 23 to the fourth branch point 24.

The cooling unit 500 cools the high pressure pump 300 by the refrigerant. That is, the refrigerant branched from the second branch point 22 is supplied to the cooling unit 500 through the refrigerant supply conduit 13 and cools the high pressure pump 300 through the refrigerant. The used refrigerant is returned to the LPG fuel reservoir 100 through the refrigerant return conduit 15. At this time, the cooling unit 500 is preferably made of a structure capable of circulating the refrigerant to cool the high-pressure pump 300, the refrigerant is introduced into one side and the refrigerant is discharged to the other side. In addition, the cooling unit 500 is in contact with or not in contact with the high pressure pump 300 to cool the high pressure pump 300. However, the heat exchange of the refrigerant is preferably made of a structure that can be made most efficiently. For example, when the cooling unit 500 cools the high pressure pump 300, LPG fuel is prevented from causing a phase change (change from liquefied fuel to gas) in the low pressure part of the high pressure pump 300 by the engine heat of a hot car. can do. The injection amount of the LPG fuel supplied to the high pressure pump 300 may be adjusted in such a way as to prevent the phase change.

<제 2 실시예>Second Embodiment

The direct injection of heterogeneous fuel according to the second embodiment of the present invention is as shown in FIG. 2, and only differences from the first embodiment will be described. In the second embodiment, the first purge conduit 16 and the purge fuel supply valve 610 are not provided in comparison with the first embodiment, but the second purge conduit 17 is provided.

The second purge conduit 17 is arranged to communicate with the low pressure portion of the high pressure pump 300 and is also connected to the fifth branch point 25 of the refrigerant return conduit 15. Accordingly, the purge fuel remaining in the low pressure portion of the high pressure pump 300 is transferred to the refrigerant return conduit 15 through the second purge conduit 17 and recovered to the LPG fuel storage container 100. Therefore, if the start-up is turned off after using the LPG fuel and enters the start mode again after a certain time, it is possible to prevent the start of the mismatch. According to the second embodiment of the present invention, the cooling unit 500 primarily prevents start-up mismatch, and furthermore, the purge fuel remaining in the low pressure part of the high-pressure pump is recovered to the LPG fuel storage tank again. Inconsistency can be prevented secondarily. Content other than the above description will be replaced with the description of the above-described first embodiment.

<동작 모드><Operation Mode>

The control unit controls the operation of each valve and pump described above. The control unit (not shown) for controlling the valve and the pump is roughly operated in liquefied fuel supply mode (LPG fuel supply mode), liquid fuel supply mode (gasoline fuel supply mode), fuel switching mode, flashing mode, and start mode. can do. The liquefied fuel supply mode is a mode in which LPG fuel is selected and supplied, and the liquid fuel supply mode is a mode in which gasoline fuel is selected and supplied. The fuel conversion mode is a mode in which LPG fuel is converted to gasoline fuel or gasoline fuel is converted to LPG fuel. The flashing mode is used for gasoline fuel, but when the engine is turned off, it is a mode for cooling the high-pressure pump and purging the remaining purge fuel before entering the start mode again. The start mode is a mode in which the driver attempts to turn on the engine at any point after the driver opens the door from the outside and enters the driver's seat (or wirelessly opens the door) and inserts the ignition key. Therefore, flashing mode is performed until the start form.

The flashing mode is not activated when the ignition is turned off in gasoline fuel supply mode. This is because no purge fuel remains. Flashing mode is the LPG fuel supply mode, which is operated before the start mode when the start is turned off after a certain time.

3 illustrates an example of the flashing mode, assuming that a short time is required before starting the LPG fuel supply mode and entering the start mode again. That is, as an example, it may be assumed that the driver is briefly refueling to refill the fuel. The driver will turn off the engine in LPG fuel supply mode to refill the fuel, and then start the engine until the fuel is full. When the driver turns off the ignition, the flashing mode is operated. In the flashing mode, the high pressure pump 300 is cooled and the purge fuel is discharged intermittently. That is, as shown in FIG. 3, the nth flashing mode is repeatedly operated, and the first flashing mode turns on the LPG fuel supply valve 120 to operate the LPG fuel pump and at the same time the purge fuel supply valve ( By turning on the 610 and the refrigerant supply valve 510, the high pressure pump 300 is cooled and the remaining purge fuel is discharged. However, the purge fuel supply valve 610 may be ON for a short time at the beginning of the flashing mode, and the refrigerant supply valve 510 may be interlocked with the purge fuel supply valve 610 on / off or LPG depending on the use environment. On / off of the fuel supply valve 120 may be interlocked. After the first flashing mode ends, the second flashing mode starts in the same manner after a certain time. The nth order flashing mode is repeated until the start mode.

Start mode may be initiated when the driver wirelessly opens a car door or sits in the driver's seat. At the beginning of the start mode, the LPG fuel supply valve 120 is turned on, and at the same time, the LPG fuel pump 110 supplies the LPG fuel to the high pressure pump 300 at a pressure of approximately 10 bar. At this time, the refrigerant supply valve 510 is also linked (ON) and the purge fuel supply valve 610 is OFF (OFF) state. After a certain time, when the gasoline fuel supply valve 220 is turned on and the gasoline fuel starts to be supplied, the LPG fuel supply valve 120 is turned off. However, the refrigerant supply valve 510 may be turned off in conjunction with the LPG fuel pump 110 or may be turned off after some time passes depending on the use environment. In the initial stage when the gasoline fuel supply valve 220 is turned on and the gasoline fuel is supplied, the LPG fuel pump 110 supplies gasoline fuel at a pressure of 10 bar (because, LPG fuel still remains in the fuel supply conduit, where Since the pressure is 10 bar), the gasoline fuel is supplied again at a pressure of 5 bar after the LPG fuel remaining in the conduit is exhausted (or after a certain time).

4 is a view illustrating another example of the flashing mode, assuming that a long time is required for the start of the LPG fuel supply mode to be turned off and to enter the start mode again. In this case, when a long time elapses after the start is turned off, the operation principle is the same except that the flashing mode is performed only once compared to FIG. 3. However, in the long time mode, although the flashing mode of the short time mode described above is repeated n times, the driver's seat is not returned (because at least a longer time is passed than the short time mode). It will be common for the flashing mode of the long time mode to be activated by the driver's return after the flashing mode is completely turned off.

That is, the controller may operate the flashing mode of the short time mode for a predetermined time when the start is turned off by the LPG fuel supply mode regardless of the short time mode or the long time mode, and the time to enter the start mode is the short time mode. In the case of the operation as shown in FIG. 3, when the time to enter the start mode is a long time mode, the flashing mode of the short time mode continues for a predetermined time, the flashing mode is completely turned off, and when the driver later returns to Figure 4 To work together.

In the following description of the present invention, those skilled in the art and those skilled in the art may omit descriptions, and descriptions of such omitted components (methods) and functions may be sufficiently referred to without departing from the technical spirit of the present invention. Could be.

Description of the configuration and functions of the above-described parts have been described separately from each other for convenience of description, and any configuration and function may be implemented by being integrated into other components, or may be further subdivided as necessary.

As mentioned above, although demonstrated with reference to one Embodiment of this invention, this invention is not limited to this, A various deformation | transformation and an application are possible. That is, those skilled in the art will readily appreciate that many modifications are possible without departing from the spirit of the invention. In addition, when it is determined that the detailed description of the known function and its configuration or the coupling relationship for each configuration of the present invention may unnecessarily obscure the subject matter of the present invention, it should be noted that the detailed description is omitted. something to do.

Claims

Liquefied fuel storage container for storing liquefied fuel,

A liquid fuel reservoir for storing liquid fuel, and

And a fuel supply conduit for supplying the liquefied fuel and the liquid fuel to the high pressure pump through the same conduit.
The method of claim 1,

And a liquid fuel transfer conduit for transferring the liquid fuel of the liquid fuel reservoir to the liquid fuel confluence point of the fuel conduit of the liquefied fuel reservoir.
The method of claim 2,

The liquid fuel supplied from the liquid fuel pump of the liquid fuel reservoir is supplied to the liquid fuel confluence point in accordance with the on / off of the liquid fuel supply valve installed in the liquid fuel delivery conduit, so that the liquid fuel is supplied to the high pressure pump by the fuel supply conduit. Heterogeneous fuel direct injection device characterized in that the supply.
The method of claim 1,

The liquefied fuel pump of the liquefied fuel reservoir is a hetero-fuel direct injection device, characterized in that for pumping liquefied fuel and liquid fuel to be supplied to the high pressure pump through the fuel supply conduit.
The method of claim 1,

Heterogeneous fuel direct injection device characterized in that it further comprises a cooling unit for cooling the high pressure pump by being installed in the peripheral region of the high pressure pump.
The method of claim 5, wherein

And a refrigerant supply conduit branched at one point of the fuel supply conduit to supply the refrigerant to the cooling unit.
The method of claim 6,

The refrigerant is liquefied fuel supplied from the liquefied fuel reservoir,

And the liquefied fuel is directly supplied to the cooling unit according to the on / off of the refrigerant supply valve installed in the refrigerant supply conduit.
The method of claim 6,

And a refrigerant return conduit for returning the liquefied fuel used as the refrigerant in the cooling unit to the liquefied fuel reservoir.
The method of claim 8,

Further comprising a high pressure fuel supply conduit for supplying fuel to the fuel injection rail from the high pressure pump,

And discharging the gas generated by the phase change of the liquefied fuel remaining in the high pressure fuel supply conduit and transferring the gas to the refrigerant return conduit.
The method of claim 9,

Further comprising a purge conduit connecting the high pressure fuel supply conduit and the refrigerant return conduit such that purged gas is transferred to the refrigerant return conduit,

And the purged gas is transferred to the refrigerant return conduit by on / off of the purge fuel supply valve installed in the purge conduit.
The method of claim 8,

And discharging the gas generated by the phase change of the liquefied fuel remaining in the low pressure portion of the high pressure pump to transfer the refrigerant to the refrigerant return conduit.
The method of claim 11,

And a purge conduit for connecting the low pressure portion of the high pressure pump and the refrigerant return conduit so that the purged gas is transferred to the refrigerant return conduit.
The method of claim 1,

And a control unit for controlling at least one of a liquefied fuel supply mode, a liquid fuel supply mode, a fuel switching mode, a flashing mode, and a start mode.

The fuel conversion mode, which converts liquefied fuel into liquid fuel,

Turn on the liquid fuel supply valve, turn off the liquefied fuel supply valve,

The liquefied fuel pump is pumped at the beginning of mode switching so that the supply pressure of the liquid fuel is at least equal to the pressure in the fuel supply conduit at the time of supplying the liquefied fuel. Heterogeneous fuel direct injection device, characterized in that for pumping the liquefied fuel pump.
The method of claim 1,

And a control unit for controlling at least one of a liquefied fuel supply mode, a liquid fuel supply mode, a fuel switching mode, a flashing mode, and a start mode.

The flashing mode is,

After the start of the liquefied fuel supply mode is turned off and before entering the start mode, the purge fuel supply valve is turned on to purge the gas generated by the phase change of the liquefied fuel to the refrigerant return conduit, and the refrigerant supply valve Heterogeneous fuel direct injection device characterized in that to cool the high-pressure pump by turning on (ON).