KR100850662B1 - Fuel injection valve - Google Patents

Abstract

(Problem) Provides technology that can stabilize fuel injection amount at low cost.

(Solution means) The fuel injection valve 100 is provided with an injection nozzle 121 having an injection hole 122 and an injection hole 163 having a diameter smaller than the injection hole 122 and provided downstream from the injection hole 122. The orifice plate 161 which has it, and the valve body 116 which open and close the injection port 122 are provided. While the injection hole 122 and the injection hole 163 are arranged on the same axis, the ratio of the area of the injection hole 122 to the area of the injection hole 163 (the area of the injection hole 122 / the area of the injection hole 163) ) Is set in the range of 2.5 to 7.

Description

FUEL INJECTION VALVE

1 is a cross-sectional view showing the overall configuration of one embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of part A of FIG. 1.

3 is a cross-sectional view illustrating a connection structure of a fuel injection valve to a delivery pipe and a return pipe.

4 is an enlarged cross-sectional view of part B of FIG. 3.

5 is a cross-sectional view showing the configuration of a tip portion of a fuel injection valve.

It is a figure explaining the operation | molding of a sealing member in the recessed part of a valve body.

7 is an enlarged view showing a conventional mounting structure in which a sealing member is attached to a recess of the valve body.

It is a figure explaining the conventional operation | movement which shape | molds a sealing member in the recessed part of a valve body.

9 is a graph showing the relationship between the area ratio and the flow rate.

10 is a graph showing the relationship between the area ratio and the flow rate deviation.

It is a figure which shows the 1st example of the connection structure of a fuel injection valve and a delivery pipe.

It is a figure which shows the 2nd example of the connection structure of a fuel injection valve and a delivery pipe.

It is a figure which shows the 3rd example of the connection structure of a fuel injection valve and a delivery pipe.

It is a figure which shows the 4th example of the connection structure of a fuel injection valve and a delivery pipe.

It is a figure which shows the conventional example of the connection structure of a fuel injection valve and a delivery pipe.

Explanation of symbols for the main parts of the drawings

100 fuel injection valve

110 main body

111 holes

110a through hole

113 needle valve

114 barrel member

114a hole

115 valve shaft

115a hole

115b through hole

115c supply hole

116 valve body

116a flat area (mounting surface)

116b protrusion (butting part)

117 recess

121 spray nozzles

121a Nozzle seat surface (butting surface)

122 nozzle

123 Cylindrical section

125 coil spring

127 spring pin

127a hole

129 Seal member (elastic body)

129a outer periphery

129b protrusion (sealing part)

131 housing

131a shaft end

131b flange

133 fixed core

133a hole

135 solenoid coil

137 connector

141 inlet cover

143 fuel introduction passage

145, 171 delivery pipe

147, 148 filters

149 return pipe

149a euro

149b, 171a mounting holes

151-155, 173 O ring

157 cover

161 orifice plate

163 spray hole

175 backup ring

177 stop ring

200 mold

201 opponent

C1 fuel introduction space

C2 fuel storage

Patent Document 1: JP-A-63-54861

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection valve for an internal combustion engine, and more particularly, to a fuel injection valve including an injection nozzle having an injection port and an orifice plate provided downstream of the injection nozzle and having an injection hole smaller in diameter than the injection hole. will be.

The conventional fuel injection valve for internal combustion engines is disclosed by the said patent document 1, for example. The fuel injection valve disclosed in this publication is a fuel injection valve for a gasoline engine, and has an injection nozzle having an injection port and an orifice plate provided downstream of the injection nozzle and having an injection hole smaller in diameter than the injection hole. have. In the fuel injection valve of such a structure, the injection amount of fuel is determined according to the size of the injection hole formed in the orifice plate. For this reason, the injection amount of fuel can be adjusted by selecting the orifice plate from which the injection hole diameter differs. In addition, an orifice plate is comprised by a thin plate. For this reason, the injection hole can be formed in an orifice plate with high precision by press working. Therefore, it is not necessary to process the injection port with high precision, and the fuel injection valve can be manufactured at low cost.

In the case of injecting a liquid fuel such as gasoline using the fuel injection valve of the above-described configuration, the influence on the fuel injection characteristics according to the diameter of the injection port is small. However, in the case of injecting a liquefied fuel which is easy to vaporize, such as LP gas (liquefied petroleum gas), there is a fear that the fuel injection characteristics change depending on the diameter of the injection port.

The present invention has been made in view of the above, and has a fuel injection valve including an injection nozzle having an injection port, and an orifice plate provided downstream of the injection nozzle and having an injection hole smaller in diameter than the injection hole. It is an object of the present invention to provide a technique for preventing a change in fuel injection characteristics depending on the diameter of a.

Means to solve the problem

The fuel injection valve of the present invention is used to inject liquefied fuel. Typically used to inject LP gas (liquefied petroleum gas).

One aspect of the fuel injection valve which concerns on this invention is provided with the injection nozzle which has an injection port, the orifice plate provided in the downstream of an injection nozzle, and having an injection hole whose diameter is smaller than an injection hole, and the valve body which opens and closes an injection port, have. The injection nozzle and the orifice plate are provided so that the injection port and the injection hole are arranged on the same axis.

In the fuel injection valve including the injection nozzle having the injection port and the orifice plate having the injection hole, the fuel injection amount is determined according to the size of the injection hole of the orifice plate. Generally, the injection port of the injection nozzle is formed by cutting. In addition, since the orifice plate can be formed into a thin plate, the injection hole of the orifice plate is formed by press working with high processing accuracy. For this reason, it is not necessary to process the injection port of an injection nozzle with high precision.

Here, the present inventors consider that the injection characteristic of the fuel injection valve changes according to the ratio of the injection hole area and the injection hole area (area of injection hole / area of injection hole), and thus (area of injection hole / area of injection hole) The variation of the fuel injection amount (flow rate) with respect to the fuel injection amount (flow rate) and (the area of the injection port / the area of the injection hole) was examined. The deviation of the fuel injection amount (flow rate) is calculated using a statistical method based on the fuel injection amount (flow rate) measurement results of a plurality of fuel injection valves having the same configuration and the same area ratio. As a result, when the area ratio (= area of the injection hole / area of the injection hole) is less than 2.5, the fuel injection amount changes greatly when the area ratio changes, but when the area ratio is 2.5 or more, the change in the fuel injection amount is small even if the area ratio changes. I found out. That is, when (the area of the injection port / the area of the injection hole) is 2.5 or more, it was found that even if the area (diameter) of the injection port is varied, the change in the fuel injection amount is small. In addition, when (area of injection hole / area of injection hole) exceeds seven. Although the variation in the fuel injection amount was large, it was found that the variation in the fuel injection amount was small when (the area of the injection port / the area of the injection hole) was 7 or less. That is, when (the area of the injection port / the area of the injection hole) was 7 or less, it was found out that the variation in the fuel injection amount was small even when the area (diameter) of the injection port was varied.

Therefore, in this aspect, the area ratio (area of the injection hole / area of the injection hole) of the injection port and the injection hole is set in the range of 2.5-7. Moreover, the range of 2.5-7 includes the range of about 2.5-7.

The other aspect of this invention has the following structures in addition to the said structure.

One of the injection nozzle and the valve body has abutting surface. In addition, the other side of the injection nozzle and the valve body includes a contact surface, a mounting surface formed in a direction away from the contact surface from a contact point facing the contact surface, and a recess formed on the mounting surface. And an elastic body attached to the recessed portion.

An "elastic body" is typically formed of rubber. Moreover, the elastic body which has various shapes, such as disk shape and ring shape, can be used. As a method of forming an elastic body in a recessed part, the method of shape | molding an elastic body in a recessed part is typically used using a metal mold | die. The description "the recess is formed in the mounting surface" means the structure provided with the mounting surface on the outer peripheral side of the recess.

And when a valve body moves to the direction which closes a jet opening, after the elastic body contacts the contact surface, it is comprised so that the said contact part may contact the said contact surface. Thereby, since excessive force is prevented from applying to an elastic body, durability of an elastic body improves.

Further, for example, in the case of forming an elastic body against a valve body or one of the injection nozzles and molding the elastic body in a recess formed in one of the valve body or the injection nozzle, the valve body or the injection is performed in the forming region of the elastic body. One part of a nozzle and a metal mold | die can be eliminated. For this reason, in the shaping | molding area | region of an elastic body, the clearance gap which allows the fitting of one of a valve body or an injection nozzle, and a metal mold | die is eliminated, and a burr can be prevented from generating by a clearance gap.

In addition, even when the elastic body is swollen by the fuel and the portion around the contact point in the normal operation protrudes from the mounting surface, the protruding portion does not touch the contact surface. Thereby, peeling of the elastic body by abutment can be prevented.

Therefore, the influence by peeling of an elastic body (including burr), for example, the fall of the sealing characteristic and flow volume characteristic of a fuel injection valve can be prevented.

Implement the invention  Best form for

EMBODIMENT OF THE INVENTION Below, one Example of this invention is described, referring drawings. This embodiment is configured as an electronic fuel injection valve for LP gas (liquefied petroleum gas). 1 is a cross-sectional view showing the overall configuration of a fuel injection valve according to the present embodiment. FIG. 2 is an enlarged view of a portion A of FIG. 1. 5 is a cross-sectional view showing the distal end portion of the fuel injection valve according to the present embodiment.

As shown in FIG. 1, the electronic fuel injection valve 100 of this embodiment has a body 110 extending in the axial direction. The main body 110 is formed in a substantially cylindrical shape. The hole 111 inside the main body 110 constitutes a fuel passage of LP gas (hereinafter referred to as "fuel"). In the hole 111 of the main body 110, a cylindrical fixing core 133 and a needle valve 113 are provided. The fixed core 133 is fixed to the main body 110. The needle valve 113 is comprised by the cylinder member 114, the valve shaft 115, and the valve body 116. As shown in FIG. The cylinder member 114 is formed of the magnetic material, and is movable along the inner peripheral surface of the main body 110. The valve body 116 is provided at the axial end of the valve shaft 115.

The injection nozzle 121 is fixed to one end of the main body 110 in the axial direction, that is, the front end, so as to face the front end of the valve body 116 of the needle valve 113 (see FIG. 2). The injection nozzle 121 is formed in the cup shape which has the circular injection port 122 in the bottom part (tip part). The injection port 122 is formed by cutting. The coil spring 125 is provided in the hole 133a of the fixed core 133. The needle valve 113 is a force that moves in the direction in which the tip of the valve body 116 abuts against the nozzle seat surface 121a (see FIG. 5) of the injection nozzle 121 by the elastic force of the coil spring 125. Receive. When the valve body 116 of the needle valve 113 abuts on the nozzle seat surface 121a of the injection nozzle 121, the injection port 122 is closed. The elastic force of the coil spring 125 can be adjusted by the cylindrical spring pin 127 provided in the cylinder member 114.

Into the hole 127a of the spring pin 127, the hole 133a of the fixing core 133, the hole 114a of the cylinder member 114 of the needle valve 113, and the hole 115a of the valve shaft 115. The fuel passage is comprised by this.

The valve body 116 corresponds to the "valve body" of the present invention. The injection nozzle 121 corresponds to the "injection nozzle" of the present invention. The nozzle seat surface 121a of the injection nozzle 121 corresponds to the "butting surface" of this invention. The injection port 122 of the injection nozzle 121 corresponds to the "injection port" of the present invention.

An orifice plate 161 having a circular injection hole 163 having a smaller diameter than the injection port 122 of the injection nozzle 121 is fixed to the tip portion (downstream side) of the injection nozzle 121 (see FIG. 5). . The orifice plate 161 is composed of a thin plate, and the injection hole 163 is formed by press working. The injection hole 163 of the orifice plate 161 and the injection port 122 of the injection nozzle 121 are arrange | positioned on the same axis.

The injection hole 163 of the orifice plate 161 corresponds to the "injection hole" of the present invention.

The main body 110 is surrounded by the housing 131 made of a resin except for both ends in the axial direction. In the housing 131, a solenoid coil 135 is provided to surround the fixed core 133. The solenoid coil 135 and the fixed core 133 comprise a valve drive mechanism for driving the needle valve 113.

The solenoid coil 135 is connected to the power supply device via the connector 137. When a current flows in the solenoid coil 135, an electromagnetic force is generated between the fixed core 133 and the cylinder member 114 of the needle valve 113, so that the cylinder member 114 of the needle valve 113 is fixed to the fixed core 133. Dragged to) In this way, the valve body 116 of the needle valve 113 is separated from the nozzle seat surface 121a of the injection nozzle 121, and the injection port 122 is opened to inject fuel.

3 illustrates a state in which the fuel injection valve 100 is connected to the delivery pipe (fuel distribution pipe 145) and the return pipe 149. 4 is an enlarged view of a portion B of FIG. 3.

As shown in FIG. 3, the housing 131 of the fuel injection valve 100 and the tip portion of the main body 110 exposed from the housing 131 are accommodated in the inlet cover 141 formed in a substantially cylindrical shape. It is. The inlet cover 141 is provided with a fuel introduction passage 143 for introducing fuel. And the delivery pipe 145 is connected to the fuel introduction passage 143.

The fuel supplied from the delivery pipe 145 through the fuel introduction passage 143 is, as shown in FIG. 4, to the filter 147 and the main body 110 provided between the inlet cover 141 and the main body 110. It flows into the fuel introduction space C1 formed between the main body 110 and the valve shaft 115 of the needle valve 113 through the some through hole 110a of the radial direction formed. And from the fuel introduction space C1, it flows into the hole 115a through the some through hole 115b of the radial direction formed in the valve shaft 115. As shown in FIG. The fuel introduced into the hole 115a of the valve shaft 115 is, when the needle valve 113 is located in the closed position, through the plurality of radially supplied holes 115c formed at the tip of the valve shaft 115, It flows into the fuel storage space C2 formed in the outer periphery of the valve body 116, and is stored. The fuel storage space C2 is formed by the outer circumferential surface of the valve body 116 and the inner circumferential surface of the cylindrical portion 123 (see FIG. 5) of the injection nozzle 121 surrounding the valve body 116.

Moreover, the fuel which flowed into the hole 115a of the valve shaft 115 is a hole 114a of the cylinder member 114, the hole 133a of the fixing core 133, and a spring pin, as shown in FIG. It flows out into the flow path 149a of the return pipe 149 connected to the open end of the main body 110 through the hole 127a of the 127, the hole 111 of the main body 110, and the filter 148. In other words, the fuel supplied from the delivery pipe 145 to the fuel injection valve 100 is configured to return to the return pipe 149 through the internal fuel passage of the fuel injection valve 100.

In addition, the connection of the fuel injection valve 100 and the return pipe 149 is equipped with the return pipe 149 which connects the other end of the axial direction of the main body 110, ie, the outlet side rear end of the fuel, and the end of the housing 131. In the state inserted in the hole 149b (refer FIG. 3), the inlet cover 141 is connected by attaching to the return pipe 149 with the screw which is not shown in figure.

In addition, an O ring 151 is provided between the rear end side outer circumferential surface of the main body 110 and the inner circumferential surface of the mounting hole 149b, and an O ring 153 between the outer circumferential surface of the housing 131 and the inner circumferential surface of the inlet cover 141. ) Is provided, and an O-ring 155 is provided between the outer peripheral surface of the tip side of the main body 110 and the inner peripheral surface of the inlet cover 141. As a result, leakage of fuel introduced into the fuel injection valve 100 to the outside is prevented.

On the front end side of the fuel injection valve 100, a cover 157 for mounting the fuel injection valve 100 to the engine (cylinder head or intake pipe) is disposed.

As described above, the fuel injection valve 100 of the present embodiment is provided with an orifice plate 161 having an injection hole 163 having a diameter smaller than that of the injection port 122 in the tip portion (downstream side) of the injection nozzle 121. It is. In the fuel injection valve 100 having such a configuration, the fuel injection amount when the valve body 116 is separated from the nozzle seat surface 121a and the injection port 122 is opened is formed on the orifice plate 161. It depends on the diameter of the injection hole 163 which exists, ie, an area.

However, when a fuel injection valve having such a configuration is used as a fuel injection valve for injecting a fuel that is easily vaporized, such as LP gas (liquefied petroleum gas), the diameter of the injection port 122 is increased, and the fuel is injected at the time of fuel injection. There is a risk of vaporization. If the fuel is vaporized at the time of fuel injection, the metering accuracy is changed, and there is a fear that a deviation occurs in the fuel injection amount.

Therefore, the inventors of the present invention have a ratio of the area of the injection hole 122 of the injection nozzle 121 to the area of the injection hole 163 of the orifice plate 161 (area ratio = area of the injection hole 122 / area of the injection hole 163). And the relationship with the fuel injection amount (flow rate) when the injection port 122 is in an open state. 4 is a graph showing the relationship between the area ratio and the fuel injection amount (flow rate) (cm 3 / min). 5 is a graph showing the relationship between the area ratio and the variation (%) of the fuel injection amount (flow rate).

The measurement was performed by the injection port of the injection nozzle 121 in the state where the diameter φ d2 of the injection hole 163 of the orifice plate 161 was set to 0.42 mm (the area of the injection hole 163 was set to a constant value). It measured by changing the diameter (phi d1) (the area of the injection port 122) of 122. Moreover, the deviation of fuel injection amount (flow rate) measures the fuel injection amount (flow rate) of several fuel injection valves (for example, 10 fuel injection valves) which have the same structure for each area ratio, and based on a measurement result, Calculated using statistical method.

In FIG. 4, when the ratio (area ratio) of the area of the injection hole 122 and the area of the injection hole 163 is less than about 2.5 (for example, [area ratio <2.5]), the flow rate (fuel injection amount) is changed when the area ratio is changed. ) Is greatly changed. On the other hand, when the ratio (area ratio) of the area of the injection hole 122 and the area of the injection hole 163 is about 2.5 or more (for example, [area ratio ≥ 2.5]), even if the area ratio changes, the flow rate (fuel injection amount) Is small and the flow rate (fuel injection amount) is stable.

The reason is that when the ratio of the area of the injection hole 122 and the area of the injection hole 163 is set to about 2.5 or more, the injection hole 122 formed in the injection nozzle 121 has no function of tightening the flow rate. Or the function of tightening the flow rate is deteriorated.

As mentioned above, the orifice plate 161 can be comprised by a thin plate. For this reason, the injection hole 163 of the orifice plate 161 can be formed by the press working which can process a high precision. Therefore, the injection hole 163 of the orifice plate 161 can suppress the deviation of the diameter (phi d1) to a small range. That is, the fuel injection amount from the fuel injection valve 100 can be set with high precision.

In addition, the ratio of the area of the injection hole 122 of the injection nozzle 121 to the area of the injection hole 163 of the orifice plate 161 (the area of the injection hole 122 / the area of the injection hole 163) is set to about 2.5 or more. In this case, the fuel injection amount from the fuel injection valve 100 is stable without being affected by the variation in the diameter (φ d2: area) of the injection port 122.

In FIG. 5, the ratio of the area of the injection hole 122 to the area of the injection hole 163 (the area of the injection hole 122 / the area of the injection hole 163) is approximately 7, and the variation in the flow rate (fuel injection amount) It is changing rapidly. That is, when the area ratio exceeds about 7 (for example, [area ratio> 7]), the variation in the flow rate (fuel injection amount) is rapidly increasing. On the other hand, when the area ratio is about 7 or less (for example, [area ratio ≤ 7]), variations in the flow rate (fuel injection amount) decrease. It is considered that when the area ratio exceeds about 7, the fuel LPG is vaporized, and the variation in the amount of vaporization appears as the variation in the flow rate. On the other hand, at an area ratio of about 7 or less, it is considered to be a trace amount even if the fuel is not vaporized or vaporized.

Therefore, by setting the area ratio (the area of the injection port 122 / the area of the injection hole 163) to about 7 or less, the variation in the metering accuracy due to the vaporization of the fuel can be suppressed and the fuel injection amount can be stabilized.

As described above, in the present embodiment, the ratio of the area of the injection port 122 of the injection nozzle 121 to the area of the injection hole 163 of the orifice plate 161 is in the range of about 2.5 to about 7 (for example, [ 2.5 ≤ area ratio ≤ 7]). Thereby, by increasing only the processing precision of the injection hole 163 of the orifice plate 161, without suppressing the processing precision of the injection hole 122 of the injection nozzle 121, fuel evaporation is suppressed and the fuel injection amount is accurate and stable Can be secured.

By the way, the fuel injection valve conventionally provided with the elastic body for alleviating the impact force when the front end surface of a valve body comes in contact with the nozzle seat surface of an injection nozzle shown in FIG. In this fuel injection valve, the recessed part 11a whose outer periphery has a circular shape (or ring shape) is formed in the front end surface center side of the valve body 11. And the elastic body 13 is attached to the recessed part 11a. On the front end surface of the elastic body 13, a ring-shaped protrusion 13a protruding from the front end surface of the valve body 11 toward the injection nozzle side (downward in FIG. 7) is formed. This fuel injection valve is comprised so that the front end surface of the valve body 11 may contact the nozzle seat surface of an injection nozzle after the elastic body 13 contacts the nozzle seat surface of an injection nozzle. Thereby, the durability of the elastic body 13 improves.

Usually, as shown in FIG. 8, the elastic body 13 is shape | molded in the recessed part 11a of the valve body 11 using the metal mold | die 15. As shown in FIG. The metal mold | die 15 is formed so that the surface shape of the elastic body 13 may correspond. The metal mold | die 15 is arrange | positioned facing the front end surface of the valve body 11 so that the convex part 15a may fit in the recessed part 11a of the valve body 11. At this time, the clearance gap C which allows both to fit is formed between the inner peripheral surface of the recessed part 11a of the valve body 11, and the outer peripheral surface of the convex part 15a of the metal mold | die 15. For this reason, when the elastic body 13 is shape | molded in the recessed part 11a of the valve body 11 using the metal mold | die 15, the burr 17 corresponding to the clearance C in the outer periphery of the elastic body 13 is carried out. ) (See FIG. 7) is formed. This burr 17 is swollen by liquefied fuel when the fuel injection valve is used. In addition, when the front end surface of the valve body 11 is in contact with the wall surface of the injection nozzle, a large force is applied to the burr 17. For this reason, the burr 17 may peel from the valve body 11. When the burr 17 peels from the valve body 11, a seal characteristic and a flow volume characteristic change.

Therefore, in this embodiment, it is comprised so that the influence by the bur of the elastic body which relieves the impact force at the time of abutting a valve body against a contact surface is comprised.

Next, the structure of the valve body 116 of the needle valve 113 of a present Example is demonstrated, referring FIG.

As shown in FIG. 5, the front end surface of the valve body 116 (the surface facing the nozzle seat surface 121a of the spray nozzle 121) protrudes toward the nozzle seat surface 121a on the outer circumferential side. A ring-shaped protrusion 116b is formed. Moreover, in the inner side (inner circumferential side) of the projection part 116b, planar area | region 116a from the point which abuts with the nozzle seat surface 121a of the projection part 116b away from the nozzle seat surface 121a (upper part of FIG. 5). ) Is formed. Moreover, inside the planar area 116a, the circular recessed part 117 in which the sealing member 129 is arrange | positioned is formed. That is, the front end surface of the valve body 116 has the planar region 116a and protrusion 116b which differ in height along an axial direction in the outer peripheral side of the recessed part 117 in which the sealing member 129 is arrange | positioned. It is formed in a two-stage structure.

The outer circumferential side protrusion 116b of the front end face of the valve body 116 corresponds to the "butting part" of the present invention. The planar region 116a corresponds to the "mounting surface" of the present invention.

In the recessed portion 117, a seal member 129 such as rubber which can be elastically deformed is inserted. The outer peripheral part 129a is formed in the outer peripheral side in the surface which opposes the nozzle seat surface 121a of the sealing member 129. And the ring-shaped protrusion part 129b which protrudes toward the nozzle seat surface 121a side is formed in the position (inner side of the outer peripheral part 129a) which entered into the predetermined amount inner side from the outer peripheral edge. The outer circumferential portion 129a of the seal member 129 is formed at substantially the same height as the planar region 116a of the valve body 116.

The seal member 129 corresponds to the "elastic body" of the present invention. The outer peripheral part 129a of the sealing member 129 corresponds to the "outer peripheral part" of this invention. The ring-shaped protrusion 129b of the seal member 129 corresponds to the "seal portion" of the present invention.

The height where the protrusion 116b of the valve body 116 protrudes from the planar region 116a is the height at which the protrusion 129b of the seal member 129 protrudes from the outer circumferential portion 129a (or the planar region 116a). It is set lower. Thus, when the needle valve 113 moves in the direction of closing the injection port 122 of the injection nozzle 121, first, the protrusion 129b of the seal member 129 abuts on the nozzle seat surface 121a. After the protrusion 129b is elastically deformed, the protrusion 116b of the valve body 116 abuts on the nozzle seat surface 121a, and the movement of the needle valve 113 is stopped. Therefore, excessive force can be prevented from acting on the seal member 129.

The seal member 129 is molded into the recess 117 of the valve body 116 using, for example, the mold 200 shown in FIG. 6. The mating surface 201 of the metal mold | die 200 with the valve body 116 is formed in the shape corresponding to the front-end surface shape of the valve body 116. As shown in FIG. That is, the mating surface 201 of the metal mold | die 200 corresponds to the part 200a corresponding to the shape of the axial cross section of the protrusion part 116b of the valve body 116, the planar area 116a of the valve body 116, and It is formed in the shape which has the part 200b corresponding to the shape of the outer peripheral part 129a of the sealing member 129, and the part 200c corresponding to the shape of the ring-shaped protrusion 129b of the sealing member 129. As shown in FIG. Moreover, the part 200b is formed in the front end surface of the convex part 200d which protrudes from the part 200a.

When shaping the sealing member 129, the convex part 200d of the mating surface of the metal mold | die 200 is arrange | positioned so that it may fit inside the protrusion part 116b of the valve body 116. As shown in FIG. Here, in the present embodiment, the outer circumferential portion 129a of the seal member 129 is formed at the same height as the planar region 116a formed inside the protruding portion 116b of the valve body 116. For this reason, the front end surface of the valve body 116 and the mating surface 201 of the metal mold | die 200 are not fitted in the shaping | molding area | region of the sealing member 129. That is, in the shaping | molding area | region of the sealing member 129, the clearance gap which allows the fitting of the front end surface of the valve body 116 and the mating surface 201 of the metal mold | die 200 is not formed.

In the present embodiment, the tip shape of the valve body 116 has a two-stage structure composed of the tip end surface of the protrusion 116b and the planar region 116a, which are different in axial position. Moreover, the outer peripheral part 129a of the sealing member 129 is formed in substantially the same height as the planar area 116a.

Thereby, in the shaping | molding area | region of the sealing member 129, the part which the valve body 116 and the metal mold | die 200 fit together can be eliminated. That is, in the shaping | molding area | region of the sealing member 129, the clearance gap which allows the fitting of the valve body 116 and the metal mold | die 200 can be eliminated. Therefore, in the shaping | molding area | region of the sealing member 129, it can prevent that a burr generate | occur | produces in the sealing member 129 by the clearance gap which allows the fitting of the valve body 116 and the metal mold | die 200. Thereby, the influence by peeling of a burr can be prevented.

In addition, the force generated when the ring-shaped protrusion 129b is pressed against the nozzle seat surface 121a can be prevented from being concentrated at the engagement point of the valve body 116 and the seal member 129. Therefore, the sealing member 129 can be prevented from peeling from the valve body 116.

Moreover, even if the sealing member 129 swells with fuel and the outer peripheral part 129a protrudes more than the planar area | region 116a of the valve body 116, this protruded part may be the nozzle seat surface (of the injection nozzle 121). 121a) does not touch. Therefore, peeling of the sealing member 129 by the contact can be prevented.

In addition, the fuel injection valve 100 inserts the front end side (injection nozzle 121 side) (for example, the front end side of the housing 131) into a mounting hole on the internal combustion engine side formed in the cylinder head or the intake pipe. The rear end side (opposite side to the injection nozzle 121) (for example, the rear end side of the housing 131) is mounted by inserting it into the mounting hole of the return pipe or the delivery pipe (fuel distribution pipe). In addition, in the embodiment shown in FIGS. 1-4, although the rear end side (upper side of FIG. 1, FIG. 2) of the fuel injection valve 100 is inserted in the mounting hole of the return pipe 149, the delivery pipe 145 ) May be arranged at the return pipe 149 position, and the rear end side (above in FIGS. 1 and 2) of the fuel injection valve 100 may be inserted into the mounting hole of the delivery pipe 145.

At this time, if the axis of an internal combustion engine side mounting hole and the axis of a return pipe or the mounting hole of a delivery pipe are shifted | deviated, there exists a possibility that the fuel injection valve 100 may incline with respect to a return pipe or a delivery pipe. For example, as shown in FIG. 15, the fuel injection valve 100 may be inclined and inserted in the mounting hole 171a of the delivery pipe 171. FIG. In this case, the shaft end portion 131a of the housing 131 of the fuel injection valve 100 interferes with the delivery pipe 171 (the part enclosed by a circle in the figure). When the shaft end portion 131a interferes with the delivery pipe 171, the amount of deformation of the O-ring 173 disposed between the outer circumferential surface of the housing 131 and the inner circumferential surface of the delivery pipe 171 becomes nonuniform, resulting in an O-ring 173. There exists a possibility that the sealing property by this may fall.

Therefore, in the present embodiment, the axial end portion of the housing 131 of the fuel injection valve 100 forms an interference prevention structure that prevents the interference with the delivery pipe 171. In the interference prevention structure, the outer diameter of the downstream side of the groove wall constituting the groove to which the O-ring is to be mounted at the portion of the fuel injection valve 100 that is inserted into the mounting hole 171a of the delivery pipe 171 is the width of the groove wall. It is formed smaller than the outer diameter. The 1st-4th example of an interference prevention structure is shown to FIGS. 11-14.

In the first example shown in FIG. 11, the backup ring 175 for mounting and the stop ring 177 having an outer diameter smaller than the outer diameter of the backup ring 175 form a groove portion for mounting the O ring 173. It is provided as a groove wall. The backup ring 175 is provided at the shaft end portion 131a of the housing 131. The stop ring 177 is fitted to the outer periphery of the shaft end of the main body 110, which protrudes from the shaft end 131a of the housing 131. The O-ring 173 is provided between these groove walls. Moreover, the outer diameter (outer diameter downstream of the backup ring 175) of the shaft end part 131a of the housing 131 is formed smaller than the outer diameter of the backup ring 175. As shown in FIG. Thus, even when the fuel injection valve 100 is mounted in the inclined state to the mounting hole 171a of the delivery pipe 171, it is possible that the shaft end portion 131a of the housing 131 interferes with the delivery pipe 171. Avoided. As a result, the tightening value of the O ring 173 becomes the same over the entire circumference, and the sealing property by the O ring 173 is secured. Also, the O ring 173 protrudes from the groove portion by the pressure of the fuel is prevented by the backup ring 175.

In the 2nd example shown in FIG. 12, the outer periphery of the shaft end part 131a of the housing 131 is formed in taper shape, and the outer diameter of the shaft end part 131a is set smaller than the outer diameter of the backup ring 175. FIG. Otherwise, it is the same structure as the 1st example shown in FIG. Thereby, similarly to the first example, even when the fuel injection valve 100 is mounted to the mounting hole 171a of the delivery pipe 171 in an inclined state, the shaft end portion 131a of the housing 131 is provided with the delivery pipe ( Interference with 171 is avoided. As a result, the sealability by the O-ring 173 is secured. Also, the O ring 173 protrudes from the groove portion by the pressure of the fuel is prevented by the backup ring 175.

In the third example shown in FIG. 13, a plan having an outer diameter equal to (including almost the same) as the outer diameter of the backup ring 175 of the first example shown in FIG. 11 at the shaft end portion 131a of the housing 131. Branch portion 131b is formed. In addition, the outer diameter of the shaft end part 131a is set smaller than the outer diameter of the flange part 131b similarly to the 1st example shown in FIG. That is, the flange part 131b integrally formed in the shaft end part 131a uses the backup ring 175 as well. Thereby, similarly to the 1st example shown in FIG. 11, even when the fuel injection valve 100 is mounted in the inclined state to the mounting hole 171a of the delivery pipe 171, the axial end part of the housing 131 ( It is avoided that 131a interferes with the delivery pipe 171. As a result, the sealability by the O-ring 173 is secured. In addition, the o-ring 173 protruding from the groove portion by the pressure of the fuel is prevented by the flange portion 131b of the shaft end portion 131a. In the third example, the number of parts can be reduced.

In the fourth example shown in FIG. 14, the shaft end portion 131a of the housing 131 is tapered in such a manner that the maximum outer diameter of the cross section is substantially equal to the outer diameter of the flange portion 131b of the third example shown in FIG. 13. Formed. The outer diameter of the part except the largest outer diameter part of the shaft end part 131a is formed smaller than the outer diameter of the flange part 131b. In the fourth example, the outer peripheral surface of the shaft end portion 131a is formed in a tapered shape, whereby the shaft end portion 131a serves as the backup ring 175 of the first and second examples. Thereby, similarly to the 1st example shown in FIG. 11, even when the fuel injection valve 100 is attached in the inclined state to the mounting hole 171a of the delivery pipe 171, the shaft end part of the housing 131 is carried out. It is avoided that 131a interferes with the delivery pipe 171. As a result, the sealability by the O-ring 173 is secured. In addition, the O-ring 173 protruding from the groove portion by the pressure of the fuel is prevented by the end portion of the shaft end portion 131a. In the fourth example, the number of parts can be reduced.

This invention is not limited to the structure demonstrated in the Example, A various change, addition, and deletion are possible within the range which does not deviate from the summary of this invention.

In the embodiment, the fuel injection valve 100 for injecting the LP gas (liquefied petroleum gas) has been described, but the technique disclosed in the present invention is not limited to the LP gas, but various liquefaction such as LN gas (liquefied natural gas) It is applicable to the fuel injection valve which injects fuel.

The configuration of the fuel injection valve is not limited to the configuration described in the embodiment.

In the Example, although the sealing member 129 was provided in the valve body 116 side, you may provide the sealing member 129 in the injection nozzle 121 side. In this case, the nozzle seat surface 121a of the injection nozzle 121 has a plane area which is about the same height as the outer peripheral part 129a of the sealing member 129, and the ring which protrudes toward the valve body 116 rather than this plane area | region. It consists of a two-stage structure by a projection of a shape. On the other hand, the front end surface of the valve body 116 is comprised with a flat surface.

In the embodiment, the planar region 116a of the valve body 116 and the outer peripheral portion 129a of the seal member 129 are formed at the same height (no step), but may be formed to have a step.

Various connection methods can be used as a method of connecting a fuel injection valve, a delivery pipe, and a return pipe.

Each structure described in the embodiments may be used alone, or may be used in combination of a plurality selected appropriately.

The fuel injection valve of this invention can be comprised as follows.

(Aspect 1) "One end of an axial direction is inserted in the mounting hole formed in the internal combustion engine side, and the other end of an axial direction is inserted into the mounting hole of a delivery pipe or a return pipe, and the said internal combustion engine and the said delivery pipe or said return A fuel injection valve mounted between the pipes

While forming a groove wall for mounting the O-ring on the outer circumference of the other end inserted into the mounting hole of the delivery pipe or the return pipe, the outer diameter of the portion excluding the groove wall at the other end is the outer diameter of the groove wall. The fuel injection valve is set smaller.

As one end and the other end of the axial direction, for example, one end and the other end of the housing of the fuel injection valve are used.

If the axis of the internal combustion engine side mounting hole and the axis of the delivery hole of the delivery pipe or return pipe are shifted, there is a fear that the fuel injection valve is mounted between the internal combustion engine and the delivery pipe or return pipe in an inclined state. In this case, the other end of the fuel injection valve interferes with the delivery pipe or the return pipe, and there is a concern that the sealing property due to the O-ring is lowered.

In the present invention, even when the fuel injection valve is mounted between the internal combustion engine and the delivery pipe or the return pipe in an inclined state, the other end of the fuel injection valve is prevented from interfering with the delivery pipe or the return pipe. Sealing can be secured.

(Aspect 2) "The fuel injection valve of Claim 2 WHEREIN: The said contact part has a ring-shaped protrusion part, The said mounting surface is formed in the ring-shaped protrusion part, The fuel injection valve characterized by the above-mentioned."

(Aspect 3) "The fuel injection valve of Claim 2 or 2 WHEREIN: The said elastic body is provided in the said valve body, The fuel injection valve characterized by the above-mentioned."

(Aspect 4) The fuel injection valve according to the second or the second aspect, wherein the recess is formed in an outer circumference, the elastic body is formed in a disc shape, and protrudes in the abutting surface direction. A fuel injection valve having a ring-shaped seal portion.

(Aspect 5) "A fuel injection valve according to aspect 3 or 4, wherein the elastic body has an outer circumference of the same height as the mounting surface on the outer circumference of the seal portion.

According to the structure of each aspect of this invention, in the fuel injection valve for liquefied fuel provided with the injection nozzle which has an injection hole, and the orifice plate which has an injection hole, the fuel injection amount can be stabilized at low cost.

Claims (3)

A fuel injection valve for injecting liquefied fuel, An injection nozzle having an injection port, An orifice plate provided downstream from the injection nozzle and having an injection hole smaller in diameter than the injection hole; A valve body for opening and closing the injection port; One of the injection nozzle and the valve body has a contact surface, and the other of the injection nozzle and the valve body has a contact portion and an elastic body, and when the valve body moves in the direction of closing the injection port, After the elastic body abuts on the contact surface, the contact portion is configured to contact the contact surface, The said injection port and the said injection hole are arrange | positioned on the same axis, and the ratio of the area of the said injection hole and the area of the said injection hole is set to the range of 2.5-7, The fuel injection valve characterized by the above-mentioned. The method of claim 1, The other side of the said injection nozzle and the said valve body is the mounting surface formed in the direction away from the said contact surface from the contact point which contact | connects the said contact surface with the said contact surface inside the said contact part, and the said mounting surface And a concave portion formed in the concave portion, wherein the elastic body is attached to the concave portion. The method of claim 2, The contact portion has a ring-shaped protrusion, and the mounting surface is formed inside the ring-shaped protrusion.

Images