KR101583526B1 - Fuel supply apparatus for liquid phase LPG - Google Patents

Abstract

The present invention relates to a fuel injection system for an internal combustion engine, which comprises a fuel rail, a plurality of injectors connected in series to form a module form so that liquid LPG fuel can be supplied and recovered, Supply device.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a fuel supply apparatus for LPG,

The present invention relates to an LPG liquid-phase injected fuel supply apparatus that can be used in an LPG engine and a bifurcational engine, and is provided with a fuel rail connected to a fuel pump and charged with high- The present invention relates to an LPG liquid-phase injection type fuel supply device that is assembled and installed in a module form so as to be connected.

Liquid Phase LPG Injection (LPLI) fuel supply method is the latest vehicle LPG fuel supply method that has been actively used since 1994 in advanced foreign countries (mainly in the Netherlands). In the conventional LPG engine, the LPG fuel stored in the bomb is supplied to the engine through a mixer and a vaporizer, and the LPG engine is connected to a control unit It is difficult to precisely control the amount of fuel injected by the fuel injection valve. Therefore, it is difficult to start the engine in the winter, the power performance and fuel efficiency are lowered, and the tar problem that occurs when the LPG fuel is burned causes unstable idling and frequent shutdown during starting.

To solve this problem, an LPLI system, in which a LPG fuel is directly injected into a high-pressure liquid phase through an injector without using a mixer and a vaporizer, has appeared. Since the LPLI engine injects LPG fuel directly through the injector, it can control the timing and amount of injected fuel more precisely, thereby improving the fuel efficiency and power performance of the vehicle, improving the startability in winter and eliminating unnecessary maintenance There is an effect that can be done.

Conventionally, injection nozzles are provided in an intake manifold of an engine, and an injector is connected to each injection nozzle. A fuel supply line connected to a fuel pump installed in an LPG bomb is connected to an injector to inject liquid- .

At this time, as the injectors inject the liquid LPG fuel, the liquid LPG fuel in the injector is vaporized to generate air bubbles. In order to remove the air bubbles, an inlet and an outlet for the fuel are formed. As shown in FIG. 1, a plurality of injectors 10 are connected in series with an inlet and an outlet through a hose or a pipe 20 so that high-pressure liquid LPG supplied from the fuel pump 30 is supplied to a plurality of injectors 10, And the recovered fuel is returned to the LPG cylinder 40.

However, since a plurality of injectors must be connected by a hose or pipe, and each injector must be connected to the injection nozzle installed in the intake manifold, it is difficult and troublesome to install the injector and the fuel supply and recovery line.

A related art related to this is disclosed in Korean Patent Publication (10-2010-0001094) entitled " Control method for improving hot startability of LPLI system ".

KR 10-2010-0001094 A (2010.01.06.)

SUMMARY OF THE INVENTION The present invention has been conceived in order to solve the above-mentioned problems, and an object of the present invention is to provide a fuel rail system in which a plurality of injectors are connected in series so that a liquid LPG fuel can be supplied and recovered, And to provide a liquid injection type fuel supply device.

According to an aspect of the present invention, there is provided an LPG liquid-phase spray type fuel supplying apparatus including a plurality of baffles spaced apart from one another along a longitudinal direction, A fuel rail on which a fuel supply pipe is formed and a fuel return pipe is formed on the other side; A plurality of injectors each having a fuel inlet and a fuel outlet formed at one side thereof so as to be connected to each other and having a fuel injection hole for injecting fuel injected into the fuel injector; Wherein the fuel supply pipe is coupled to be connected to the fuel inlet and the fuel return pipe is coupled to be connected to the fuel outlet so that a plurality of injectors are connected in series through the fuel rail.

The fuel supply pipe and the fuel return pipe of the fuel rail are each formed with a protrusion at a central portion of the outer circumferential surface thereof. The fuel supply pipe and the fuel return pipe have end portions connected to the fuel inlet of the injector And the fuel outlet, and the projecting portion is pushed by the fixing plate so that the fuel rail and the injector are engaged.

In addition, the fixing plate is formed with a pair of cut-away portions which are opened at one side, and the fixing plate is formed in a 'C' shape so as to form a guide portion bent at both ends thereof, and the injector has a flange portion The fixing plate is slidably engaged with the injector so that the flange portion is inserted into the guide portion, and the protrusion is engaged by being pressed by the periphery of the cutout portion.

In addition, the fuel inlet and the fuel outlet of the injector are formed with an upper groove on an upper surface thereof, a sealing member is interposed in the lower groove, and the protrusion is inserted into the lower groove to closely contact the sealing member.

The injector may further include an adapter coupled to one side of the injector and an injection nozzle coupled to the other side of the adapter, wherein the fuel injection hole of the injector and the lower end of the injection nozzle are connected by a communicating tube inserted therein. do.

The injector may further include an adapter coupled to one side of the injector, an injection nozzle spaced apart from the adapter, and a connection hose connecting the adapter and the injection nozzle, wherein the connection hose is inserted into the adapter, And the other end is connected to the lower end of the injection nozzle and connected to the fuel injection hole.

Further, the injector is coupled to be inserted into an adapter, a fixing groove is formed in the injector, and a fixing slot is formed in the adapter, and the injector and the adapter are coupled by the fixing clip.

The adapter may further include a fixing bracket having a slot formed therein, the adapter having one side passing through the slot and a fixed cap coupled to one side of the adapter, the adapter being fixed to the fixing bracket.

Also, the pipe of the fuel rail may be divided into two or more and connected to each other so that two or more unit modules, each of which connects the injector and the fuel rail, are connected and formed as one integrated module.

The divided pipe of the integral module is connected and coupled by a connection nipple and a connection socket, and the connection nipple is inserted into each of the divided pipes at the center in an annular shape, and the protrusion of the connection nipple and the end of the pipe And the pipes are connected to each other by a connecting socket having threads formed on the outer circumferential surface thereof and formed with threads on the inner circumferential surface thereof.

Further, the adapter and the spray nozzle are each coupled with a one-touch nipple so as not to fall in a direction opposite to the direction in which the connection hose is inserted.

The LPG liquid injected fuel supply apparatus of the present invention is configured in a module form so that a plurality of injectors are connected in series to a fuel rail so that liquid LPG fuel can be supplied and recovered and mounted in an intake manifold There is an advantage that it is easy to do.

1 is a schematic view showing a conventional LPG liquid-phase injected fuel supply device.
2 and 3 are an assembled perspective view and an exploded perspective view showing an LPG liquid-phase injected fuel supply apparatus according to a first embodiment of the present invention;
4 and 5 are an exploded perspective view and an assembled cross-sectional view showing a connection and a coupling structure of a fuel rail and an injector according to the present invention;
6 is a schematic cross-sectional view showing the connection structure of fuel rail and the flow of fuel according to the present invention.
7 and 8 are schematic views showing a coupling structure of unit modules according to the present invention;
9 and 10 are an assembled perspective view and a sectional view showing an LPG liquid-phase injected fuel supply apparatus according to a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the LPG liquid-phase injection type fuel supply apparatus of the present invention will be described in detail with reference to the accompanying drawings.

FIGS. 2 and 3 are an assembled perspective view and an exploded perspective view of an LPG liquid-phase injected fuel supplying apparatus according to a first embodiment of the present invention, and FIGS. 4 and 5 are views showing a connection and coupling structure of a fuel rail and an injector according to the present invention And FIG. 6 is a schematic cross-sectional view showing the connection structure of the fuel rail and the flow of the fuel according to the present invention.

As shown in the figure, the LPG liquid injection type fuel supplying apparatus 1000 according to the present invention includes a plurality of baffles 140 spaced apart from one another in the longitudinal direction, A fuel rail 100 in which a fuel supply pipe 120 is formed on one side of the baffle 140 and a fuel return pipe 130 is formed on the other side of the baffle 140; A plurality of injectors 300 having a fuel inlet 310 and a fuel outlet 320 formed at one side thereof so as to be connected to each other and having a fuel injection hole 340 formed therein so as to inject fuel injected therein; Wherein the fuel supply pipe 120 is coupled to the fuel inlet 310 and the fuel return pipe 130 is coupled to the fuel outlet 320 so as to connect the fuel rail 100 to the fuel outlet 100. [ A plurality of injectors 300 may be connected in series.

First, the fuel rail 100 is a space in which a high-pressure fuel is press-fed and filled from a fuel pump mounted on an LPG cylinder, and serves to maintain the fuel at a constant pressure. The fuel rail 100 is alternately formed with the fuel supply pipe 120 and the fuel return pipe 130 along the longitudinal direction of the pipe 110 and the fuel supply pipe 120 and the fuel return pipe 130 are formed in the same number A fuel supply pipe 120 and a fuel return pipe 130 may be formed extending perpendicularly to the pipe 110. A baffle 140 is formed to divide the inside of the pipe 110 and the baffle 140 is disposed in parallel to the fuel supply pipe 120 and the fuel return pipe 130 .

The injector 300 is a device for injecting the injected high-pressure fuel according to an electric signal. The fuel inlet 310 and the fuel outlet 320 are formed at one side of the injector 300. The fuel inlet 310 and the fuel outlet 320 are connected to each other inside the injector 300 and a fuel injection hole 340 is formed on the lower side of the injector 300 to inject the fuel . The liquid LPG fuel supplied to the fuel inlet 310 may be injected through the fuel injection hole 340 while the valve inside the injector 300 is opened and the injected remaining fuel may be exhausted through the fuel outlet 320 do. Here, since the injector 300 injects liquid LPG, the liquid LPG may be partially vaporized and remain as a gas in the flow path inside the injector 300, so that the remaining fuel injected into the injected fuel is returned to the LPG cylinder So that it can be recovered.

The fuel supply pipe 120 of the fuel rail 100 is coupled to the fuel inlet 310 of the injector 300 and the fuel return pipe 130 of the fuel rail 100 is connected to the fuel outlet of the injector 300. [ The plurality of injectors 300 may be connected in series through the fuel rail 100. The fuel injector 300 may be connected to the fuel rail 100 via a plurality of injectors 300. [

The high pressure liquid LPG fuel supplied to one side of the pipe 110 is supplied to the fuel supply pipe 120 and the fuel inlet 310 so that a part of the fuel is injected into the fuel injection hole 340 according to the operation of the injector 300 And the remaining fuel is recovered through the fuel return pipe 130 and the fuel outlet 320. [ The recovered fuel passes through the pipe 110 and the subsequent injector 300 in turn, and the fuel recovered to the other side of the pipe 110 can be connected to be recovered to the LPG cylinder.

As described above, the LPG liquid-phase injection type fuel supply apparatus of the present invention can be easily configured in a module form so that a plurality of injectors are connected in series to a fuel rail to supply and recover liquid-phase LPG fuel, So that it can be easily mounted on the vehicle.

The fuel supply pipe 120 and the fuel return pipe 130 of the fuel rail 100 each have protrusions 121 and 131 at the center of the outer circumferential surface thereof, The ends of the fuel supply pipe 120 and the fuel return pipe 130 are inserted into the fuel inlet 310 and the fuel outlet 320 of the injector 300 and the protrusions 121 and 131 are inserted into the fixing plate 200 So that the fuel rail 100 and the injector 300 can be coupled to each other.

4 and 5, the fuel rail 100 and the injector 300 are coupled to each other by the fixing plate 200. The fuel rail 100 and the fuel return pipe 120 of the fuel rail 100 are fixed by the fixing plate 200, The annular protrusions 121 and 131 formed on the tube 130 are pressed toward the injector 300 and are fastened to the fastening holes 370 formed in the injector 300 through the through holes 230 formed in the fastening plate 200, (240). The lower end of the fuel supply pipe 120 and the fuel return pipe 130 may be coupled to the fuel inlet 310 and the fuel outlet 320 of the injector 300, respectively.

The fixing plate 200 is formed with a pair of cutouts 210 spaced apart from each other. The fixing plate 200 has a guide 220 formed in a C shape and bent at both ends, The injector 300 has flanges 330 protruding from both sides of the injector 300 so that the fixing plate 200 slides on the injector 300 so that the flange 330 is inserted into the guide 220. [ And the protrusions 121 and 131 may be coupled to be pressed by the periphery of the cutout 210. [

That is, in the state where the fuel supply pipe 120 of the fuel rail 100 and the lower end of the fuel return pipe 130 are inserted into the fuel inlet 310 and the fuel outlet 320 of the injector 300, The fixing plate 200 may be slid and the fuel supply pipe 120 and the fuel return pipe 210 may be connected to the incision 210 of the fixing plate 200. [ And the protrusions 121 and 131 can be pressed toward the injector 300 by the periphery of the cutout portion 210. [

In addition, the fuel inlet 310 and the fuel outlet 320 of the injector 300 are provided with the mounting grooves 311 and 321 on the upper surface thereof, the sealing member 350 is interposed in the mounting grooves 311 and 321, 121 and 131 can be inserted into the mounting grooves 311 and 321 so that the sealing member 350 can be closely contacted. That is, the protruding portion 121 protruding from the fuel supply pipe 120 of the fuel rail 100 is inserted into the mounting groove 311 formed on the upper surface of the fuel inlet 310 of the injector 300, A sealing member 350 is interposed between the protruding portion 311 and the protruding portion 121 so that the coupling surface between the fuel supply pipe 120 and the fuel inlet 310 is sealed. Similarly, the fuel return pipe 130 may be connected to the fuel outlet 320 in the same manner.

Hereinafter, an embodiment will be described in which the injector 300 and the injection nozzle 500 are connected to each other according to the present invention.

[Example 1]

The LPG liquid injected fuel supplying apparatus 1000 according to the first embodiment of the present invention includes an adapter 400 having one side coupled to the injector 300 and a jet nozzle 500 coupled to the other side of the adapter 400, And the fuel injection hole 340 of the injector 300 and the lower end of the injection nozzle 500 may be connected by a communicating tube 510 inserted therein.

This is because the injector 300 and the injection nozzle 500 are coupled by the adapter 400 and the communicating tube 510 is connected to the fuel injection hole 340 of the injector 300 and the lower end of the injection nozzle 500 Is inserted.

At this time, the injection nozzle 500 is inserted into the adapter 400 from the upper side, and the upper side of the injection nozzle 500 is caught by the lower step inside the adapter 400. In this state, the adapter 400 is inserted into the lower side of the injector 300 So that the lower side of the injector 300 is inserted into the adapter 400. When the injection nozzle 500 is coupled to the injector 300 by the adapter 400, the upper end of the communication pipe 510 is connected to the injector 300, And can be brought into close contact with the fuel injection hole 340 of the injector 300. Thus, the liquid LPG fuel injected through the fuel injection hole 340 of the injector 300 may be injected at the lower end of the injection nozzle 500 along the communicating pipe 510. The injection nozzle 500 is configured to form an air layer 520 around the communicating pipe 510. The communicating pipe 510 is made of a material having excellent heat insulation properties such as nylon 6 and having no reactivity with the LPG fuel, It is possible to prevent the injection nozzle 500 from being clogged by icing due to vaporization of the liquid LPG injected from the lower end of the nozzle 500.

The module-shaped LPG liquid-phase injector type fuel supply device thus formed can allow the injection nozzle to be installed in the intake manifold of the engine.

[Example 2]

The LPG liquid injected fuel supplying apparatus 1000 according to the second embodiment of the present invention includes an adapter 400 to which one side is coupled to the injector 300, an injection nozzle 500 which is spaced apart from the adapter 400, And a connection hose 600 connecting the adapter 400 and the injection nozzle 500. One end of the connection hose 600 is inserted into the adapter 400, And the other end thereof may be connected to the lower end of the injection nozzle 500 to be connected thereto.

This is a configuration in which the adapter 400 is coupled to the injector 300 and the adapter 400 and the injection nozzle 500 are connected by the connection hose 600. One end of the connection hose 600 is connected to the adapter 400 And the other end of the connection hose 600 is inserted into the injection nozzle 500 and the end of the connection hose 600 is coupled to the lower end of the injection nozzle 500. The end of the connection hose 600 is connected to the fuel injection hole 340 of the injector 300,

Thus, the liquid LPG fuel injected through the fuel injection hole 340 of the injector 300 may be injected at the lower end of the injection nozzle 500 along the connection hose 600. The injection nozzle 500 is configured to form an air layer 520 around the inserted connection hose 600 and the connection hose 600 may be formed of a nylon 6 material.

In the module type LPG liquid injection type fuel supply device thus formed, the injection nozzle may be installed in the intake manifold of the engine, and then the injection hose may be used to connect the injector and the injection nozzle. Accordingly, there is an advantage that the intake manifold can be easily mounted on various kinds of engines having different intervals.

In the first and second embodiments of the present invention, the injector 300 is coupled to be inserted into the adapter 400, the injector 300 has a fixing groove 360 formed therein, and the adapter 400 A fixing slot 440 is formed and the injector 300 and the adapter 400 can be coupled by the fixing clip 450.

An annular fixing groove 360 is formed in the lower outer circumferential surface of the injector 300 so as to engage the adapter 400 with the injector 300. The adapter 400 is fixed to both sides of the outer circumferential surface and the inner circumferential surface of the adapter 400, Shaped elastic fixing clip 450 is inserted into the fixing slot 440 and the fixing groove 360 after the lower side of the injector 300 is inserted into the adapter 400 after the slot 440 is formed So that the injector 300 and the adapter 400 can be easily coupled and fixed. At this time, a step is formed in the upper side of the adapter 400, and a sealing member 430 is interposed between the step and the lower end of the injector 300 to closely contact the coupling surface.

The adapter 400 further includes a fixing bracket 700 formed with a slot 710. The adapter 400 is inserted into the slot 710 so that the fixing cap 410 is coupled to one side of the adapter 400 So that the adapter 400 can be fixed to the fixing bracket 700.

That is, a plurality of adapters 400 may be fixedly coupled to the fixing bracket 700. One side (lower side) of the adapter 400 may be inserted into the slot 710 of the fixing bracket 700 to be passed therethrough The fixed cap 410 can be coupled to one side of the adapter 400. In this case, the adapter 400 is formed with male threads on the outer circumferential surface thereof, and the fixed cap 410 is formed on the inner circumferential surface thereof with an arcuate or an acid, and the slot 710 of the fixing bracket 700 is screw- And may be formed as one long slot 710 along the longitudinal direction of the fixing bracket 700. In addition, The adapter 400 can be easily fixed to the fixing bracket 700 by the slot 710 and the fixing bracket 700 can be fixed to the engine or the intake manifold, . ≪ / RTI >

In addition, the pipe 110 of the fuel rail 100 is connected to be divided into two or more parts, so that two or more unit modules having the injector 300 and the fuel rail 100 coupled to each other are connected to form an integral module .

That is, as shown in FIGS. 7 and 8, two injectors 300 are connected in series, or two injectors 300 are connected in series to form one unit module and one injector 300 The unit module may be connected to form an integrated module. At this time, the pipes 110 of the fuel rail 100 constituting each unit module can be coupled to each other.

Accordingly, the unit modules can be assembled into an integrated module by applying to various engines such as 3-cylinder, 4-cylinder, and 6-cylinder to be mounted on the intake manifold, thereby facilitating assembly and installation.

The divided pipe 110 of the integrated module is connected and coupled by a connection nipple 150 and a connection socket 160. The connection nipple 150 has a central portion protruding in an annular shape, A sealing member 170 is interposed between the protrusion of the connection nipple 150 and the end of the pipe 110 inserted into the pipe 110 and each end of the divided pipe 110 is formed with a thread on the outer circumferential surface thereof The pipes 110 can be coupled by the connection socket 160 formed with threads on the inner peripheral surface.

That is, as shown in FIG. 6, when the pipes 110 of the unit modules are coupled to each other by using a screw coupling method, the connection nipples 150 are inserted into the ends of the pipes 110, The connecting socket 160 and the pipes 110 can be tightened by tightening the connecting socket 160 and the connecting socket 160. [ At this time, a sealing member 170 is interposed between the protruding portion of the connection nipple 150 and the end portion of the pipes 110, so that airtightness can be maintained.

The one-touch nipples 420 and 530 may be coupled to the adapter 400 and the injection nozzle 500 such that the coupling hose 600 is not inserted in the opposite direction.

That is, as shown in FIG. 10, a one-touch nipple 420 is coupled to the lower end of the adapter 400 so that the fuel injection hole 340 of the injector 300 and the end of the connection hose 600 can be held in contact with each other The one-touch nipple 530 can be coupled to the upper end of the injection nozzle 500 so that the end of the connection hose 600 inserted into the injection nozzle 500 is not separated from the injection nozzle 500. [ Thus, it is easy to prevent the connection hose 600 from coming off and to connect the connection hose 600 so as to be connected to the adapter 400 and the injection nozzle 500.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. It goes without saying that various modifications can be made.

1000: LPG liquid injection fuel supply system
100: fuel rail
110: pipe 120: fuel supply pipe
130: fuel return pipe 121, 131:
140: Baffle 150: Connecting nipple
160: connecting socket 170: sealing member
200: Fixing plate 210:
220: guide part 230: through hole
240: fastening means
300: injector 310: fuel inlet
320: Fuel discharge port 311, 321:
330: flange portion 340: fuel injection hole
350: sealing member 360: fixing groove
370: fastening ball
400: adapter 410: fixed cap
420: one-touch nipple 430: sealing member
440: securing slot 450: securing clip
500: injection nozzle 510: communicating tube
520: air layer 530: one-touch nipple
600: Connection hose
700: Fixing bracket 710: Slot

Claims (11)

A fuel supply pipe extending from the baffle to the outside of the pipe and a fuel return pipe extending from the outside of the pipe to the outside of the pipe, A fuel rail extending from the fuel rail; And
A plurality of injectors each having a fuel inlet and a fuel outlet formed at one side thereof so as to be connected to each other and having a fuel injection hole for injecting fuel injected into the fuel injector; And,
The fuel supply pipe is coupled to be connected to the fuel inlet, and the fuel return pipe is coupled to the fuel outlet so that a plurality of injectors are connected in series through the fuel rail.
The method according to claim 1,
And a fixing plate coupled to the injector,
Wherein the fuel supply pipe and the fuel return pipe of the fuel rail are each formed with a protrusion at the center of the outer peripheral surface, the end of the fuel supply pipe and the fuel return pipe is inserted into the fuel inlet and the fuel outlet of the injector, Wherein the fuel rail and the injector are coupled to each other.
3. The method of claim 2,
The fixing plate is formed with a pair of cutouts spaced apart from each other, the fixing plate being formed in a 'C' shape and having bent portions at both ends thereof,
Wherein the injector has flanges protruding on both sides thereof,
Wherein the fixing plate is slidably engaged with the injector so that the flange portion is inserted into the guide portion, and the protrusion is engaged by being pressed by the periphery of the cutout portion.
3. The method of claim 2,
Wherein the fuel inlet and the fuel outlet of the injector are formed with an upper groove on an upper surface thereof, a sealing member is provided on the lower groove, and the protruding portion is inserted into the lower groove to closely contact the sealing member. .
The method according to claim 1,
An adapter having one side coupled to the injector and a spray nozzle coupled to the other side of the adapter,
Wherein the fuel injection hole of the injector and the lower end of the injection nozzle are connected by a communicating pipe inserted therein.
The method according to claim 1,
And a connection hose that connects the adapter and the spray nozzle, wherein the connection hose includes: an adapter having one side coupled to the injector; a spray nozzle spaced apart from the adapter;
Wherein the connection hose is connected to the fuel injection hole of the injector by inserting one end of the connection hose into the adapter and by inserting the other end of the connection hose to the lower end of the injection nozzle.
The method according to claim 5 or 6,
Wherein the injector is coupled to be inserted into an adapter, a fixing groove is formed in the injector, and a fixing slot is formed in the adapter, and the injector and the adapter are coupled by a fixing clip.
The method according to claim 5 or 6,
Further comprising a fixed bracket formed with a slot,
Wherein the adapter has one side thereof passed through the slot and a fixed cap is coupled to one side of the adapter, so that the adapter is fixed to the fixing bracket.
The method according to claim 1,
Wherein the pipe of the fuel rail is divided and connected so as to be divided into two or more parts,
Wherein at least two unit modules each having an injector and a fuel rail coupled to each other are connected to form an integral module.
10. The method of claim 9,
The divided pipe of the integral module is connected and coupled by a connecting nipple and a connecting socket, and the connecting nipple is inserted into each of the divided pipes at the center in an annular protruded shape, and between the protruding portion of the connecting nipple and the end of the pipe Wherein a sealing member is interposed between each of the divided pipes, and each of the divided pipes has a thread formed on an outer circumferential surface thereof, and the pipes are coupled by a connection socket having an inner circumferential surface formed with a thread.
The method according to claim 6,
Wherein the adapter and the injection nozzle are each coupled with a one-touch nipple so as not to fall in a direction opposite to the direction in which the connection hose is inserted.

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