JP3758719B2 - Fuel injection valve for gas - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas fuel injection valve, and more particularly to a gas fuel injection valve suitable for use in a fuel injection device for an internal combustion engine for automobiles.
[0002]
[Prior art]
Recent exhaust gas regulations are indispensable in correcting the global environmental destruction caused by the automobile society that relies on petroleum fuel and gasoline. However, in addition to the problems of supply system and infrastructure, some of the promising alternative fuels for gasoline have an adverse effect on the durability and performance of existing engine components.
[0003]
Gas fuels such as natural gas and hydrogen gas are attracting attention as environmentally friendly fuels, and high-pressure gaseous fuel CNG (Compressed Natural Gas) that compresses natural gas and other gases is promising as a future alternative fuel. is there.
[0004]
In order to supply gaseous fuel to the engine, it is necessary to use a fuel injection device that measures by controlling the opening / closing time width of a fuel injection valve such as an electromagnetic solenoid valve used in conventional liquid fuel such as gasoline. it can.
[0005]
As a conventional fuel injection valve for liquid fuel, for example, the one described in JP-A-63-100261 is known.
[0006]
[Problems to be solved by the invention]
When liquid fuel and gaseous fuel are compared, liquid fuel has lubricity, so even if the solenoid valve repeats reciprocating motion, sliding wear between metals hardly occurs. However, since gaseous fuel does not have lubricity like liquid fuel, sliding wear between metals occurs, and when a conventional fuel injection valve for liquid fuel is used as it is as a fuel injection valve for gas. When it was used for a long time, the measurement accuracy was lowered due to the influence of wear, and it was found that there was a problem in durability compared to the case of using it for liquid fuel.
[0007]
An object of the present invention is to provide a gas fuel injection valve having excellent durability.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a valve abutting on a valve seat, a rod having one end attached to the valve, a plunger attached to the other end of the rod, and a central portion of the rod. A flange portion formed, a core that is disposed opposite to the plunger, and that attracts the plunger by electromagnetic force generated from a coil, and is engaged with the flange portion when the plunger is attracted by the core. And a stopper for restricting the movement of the rod, and the plunger is sucked by the core to form a gap between the valve and the valve seat, and a gas for injecting fuel gas from the gap in the fuel injection valve, e Bei the rocking motion preventing member for preventing the oscillation of the plunger, the stopper may have a cutout portion in a part thereof Has a C shape, the rocking motion preventing member, two of the stopper is obtained by forming superposed so as to face the cutout portion, With this configuration, the plunger oscillating It is possible to prevent the movement, reduce the wear even in the gas atmosphere, and extend the life.
[0011]
In the gas fuel injection valve, preferably, the swing prevention member is a first magnetic film formed on an outer peripheral surface of the plunger, and a position facing the first magnetic film, the core The second magnetic film having the same polarity as the first magnetic film is formed on the inner peripheral surface, and the plunger and the core are brought into contact with each other by adopting such a structure. Can be prevented, wear can be reduced, and life can be extended.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
[0015]
FIG. 1 is a cross-sectional view of a gas fuel injection valve according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a main part of the gas fuel injection valve according to an embodiment of the present invention. These are the top views of the stopper of the gas fuel injection valve by one embodiment of the present invention, and Drawing 4 shows the amount of wear of the ring at the time of using the fuel injection valve for gas by one embodiment of the present invention. It is a figure explaining.
[0016]
In FIG. 1, the yoke of the fuel injection valve 10 is composed of yokes 114A, 114B, and 114C. A yoke 114B is fitted inside the yoke 114C, and a coil 101 for electromagnetic generation is inserted in the gap between the yoke 114C and the yoke 114B. The upper surface of the coil is fixed by the yoke 114A, and the coil 101 is energized through the electrode terminal 108 attached to the yoke 114A. A valve guide 114D is attached to the tip of the yoke 114C, and a nozzle 114E is attached to the tip of the valve guide 114D. Plunger 102 is arranged inside yoke 114B. A rod 105 is attached to the tip of the plunger 102. A flange portion 105 </ b> A is integrally formed at the center portion of the rod 105. A spherical valve 103 is attached to the tip of the rod 105. That is, the plunger 102 and the valve 103 are connected by the rod 105. A ring-shaped valve seat 110 is fixed to the upper inner peripheral surface of the nozzle 114E, and the valve 103 is in contact with the valve seat 110.
[0017]
A cylindrical ring 112 is fixed to the upper surface of the plunger 102. A core 113 is fixed to the inner periphery of the yoke 114B. The ring 112 is slidably inserted in the inner periphery of the core 113. The ring 112 slides on the inner peripheral surface of the core 113, thereby acting as a guide in the axial direction of the plunger 102, the rod 105, and the valve 103 constituting the valve body.
[0018]
A cylindrical spring receiving member 104 is fixed to the inner periphery of the yoke 114A. A spring 107 is disposed between the spring receiving member 104 and the plunger 102 and presses the plunger 102 downward. Therefore, normally, the valve 103 is pressed against the valve seat 110 by the downward pressing force of the spring 107.
[0019]
When the coil 101 is energized through the electrode terminal 108 and a predetermined current is supplied, a magnetic force is generated in the coil 101, and the plunger 102 is attracted upward against the spring force of the spring 107. A gap is created between the valve seat 110 and the valve seat 110. A stopper 106 made of a C-shaped washer is attached inside the valve guide 114D. By engaging with a flange portion 105A formed at the center of the rod 105, the valve 110 moves upward, ie, The lift amount of the valve 103 is regulated.
[0020]
A gaseous fuel such as natural gas as fuel is supplied from a fuel supply port 109 above the fuel injection valve 10, and a hole formed in the center of the spring receiving member 104, the inside of the ring-shaped core 113, and the plunger 102 are provided. The nozzle port 111 is ejected through the formed hole, the central hole of the stopper 106 attached to the valve guide 114D, and the gap formed between the valve 103 and the valve seat 110.
[0021]
Next, the structure around the stopper 106, which is the main part of the gas fuel injection valve according to the embodiment of the present invention, will be described with reference to FIG.
[0022]
A rod 105 is attached to the tip of the plunger 102. A flange portion 105 </ b> A is formed uniformly at the center of the rod 105. A spherical valve 103 is attached to the tip of the rod 105. A ring-shaped valve seat 110 is fixed to the upper inner peripheral surface of the nozzle 114E, and the valve 103 is in contact with the valve seat 110.
[0023]
A stopper 106 made of a C-shaped washer attached to the inside of the valve guide 114D engages with a flange portion 105A formed at the central portion of the rod 105, so that the valve 110 can move out of the movement of the rod 105 in the arrow direction. Is restricted from moving upward.
[0024]
Here, in the present embodiment, a curved surface portion 106 </ b> A is formed on the inner diameter surface of the stopper 106. This shape is as shown in FIG. That is, the stopper 106 has a C shape as shown in FIG. This is because the stopper 106 is attached to the rod 105. A curved surface portion 106A is formed on the inner diameter surface of the C-shaped notch.
[0025]
The stopper 106 may originally have a function of stopping the movement of the flange portion 105A of the rod 105. However, the gap between the stopper 106 and the rod 105 is about 40 μm in the conventional liquid fuel injection valve, and a part of the stopper 106 has a notch, so it is used as a gas fuel injection valve. In this case, the rod 105 swings due to the gap and the notch, and as a result, the outer peripheral surface of the ring 112 attached to the upper end of the plunger 102 and the inner peripheral surface of the core 113 slide, As a result, the wear of 112 was accelerated.
[0026]
In contrast, in the present embodiment, by providing the curved surface portion 106A on the inner diameter surface of the stopper 106, the gap between the curved surface portion 106A and the rod 105 can be halved to 20 μm. As a result, it has become possible to double the lifetime. In addition, by setting the gap to 10 μm, it was possible to further increase the service life to three times the conventional one.
[0027]
Here, as the shape of the curved surface portion 106, the contact surface with the rod 105 may be changed from a conventional surface contact to a point contact.
[0028]
FIG. 4 is a diagram showing the relationship between the durability evaluation time of the fuel injection valve and the wear amount of the ring.
[0029]
In FIG. 4, curve A shows the amount of wear of the ring with respect to the durability evaluation time when a fuel injection valve of a type in which a conventional stopper is not provided with a curved surface portion is used in a gas atmosphere. Over time, the gap between the core and the ring increased, and the generated metal powder played the role of a grindstone, which further revealed that the wear progressed. On the other hand, curve B shows the relationship between the durability evaluation time and the wear amount of the ring when a curved surface portion is formed on the inner diameter surface of the stopper and the gap between the rod and the curved surface is 20 μm. In addition, the amount of wear after that can be reduced as compared with the prior art. As a result, it is possible to extend the life and obtain a gas fuel injection valve having excellent durability.
[0030]
According to this embodiment, by forming the curved surface portion on the inner diameter surface of the stopper, it is possible to suppress the rocking of the rod, extend the life, and improve the durability.
[0031]
Next, another embodiment of the present invention will be described with reference to FIGS.
FIG. 5 is a cross-sectional view of an essential part of a gas fuel injection valve according to another embodiment of the present invention, and FIG. 6 is a plan view of a stopper of the gas fuel injection valve according to another embodiment of the present invention. is there.
[0032]
A rod 105 is attached to the tip of the plunger 102. A flange portion 105 </ b> A is formed uniformly at the center of the rod 105. A hemispherical valve 103 ′ is attached to the tip of the rod 105. A ring-shaped valve seat 110 is fixed to the upper inner peripheral surface of the nozzle, and the valve 103 is in contact with the valve seat 110. The plunger 102 is biased by a spring 107, and the valve 103 is pressed against the valve seat 110.
[0033]
The stopper 106 made of a C-shaped washer attached inside the valve guide is composed of two stoppers 106B and 106C. Of the stoppers 106B and 106C, the lower stopper 106C is engaged with the flange portion 105A formed at the center of the rod 105, so that the rod 105 moves upward in the direction of the arrow in the direction of the arrow. Restricts movement.
[0034]
Here, the present embodiment is characterized in that the stopper 106 is composed of two stoppers 106B and 106C. This shape is as shown in FIG. That is, the stoppers 106B and 106C each have a C shape as shown in FIG. This is because the stoppers 106B and 106C are attached to the rod 105. By overlapping these two stoppers 106B and 106C so that their notch directions are opposed to each other, a circular opening 106D indicated by a broken line is formed at the center.
[0035]
Conventionally, since the C-shaped stopper has a notch, when used as a fuel injection valve for gas, the notch causes the rod 105 to swing, and as a result, the upper end of the plunger 102 As a result, the outer peripheral surface of the ring 112 attached to the inner surface and the inner peripheral surface of the core 113 slide, and the wear of the ring 112 is accelerated.
[0036]
On the other hand, in the present embodiment, the stopper 106 is composed of two stoppers 106B and 106C, and the notch portions are opposed to each other, whereby the gap between the rod 105 and the stopper 106 can be made ring-shaped. it can. The inclination angle of the rod 105 is 0.4 ° at the arc portion of the stopper, but has increased to about 1 ° at the notch portion side of the stopper, but the gap between the rod and the stopper has a gap of 40 μm. By making the ring shape, the inclination angle of the rod can be suppressed to 0.4 °, and the lifetime can be increased to 1.5 to 2 times the conventional one.
[0037]
According to the present embodiment, by using two C-shaped stoppers with the notch portions facing each other, the inclination of the rod can be suppressed, the life is extended, and the durability is improved. be able to.
[0038]
Further, by making the shape of the valve hemispherical, the weight can be reduced and the inertia weight can be reduced.
[0039]
Next, a third embodiment of the present invention will be described with reference to FIG.
FIG. 7 is a cross-sectional view of a main part of a fuel injection valve for gas according to a third embodiment of the present invention.
[0040]
A rod 105 is attached to the tip of the plunger 102. A flange portion 105 </ b> A is formed uniformly at the center of the rod 105. A hemispherical valve 103 ′ is attached to the tip of the rod 105. A ring-shaped valve seat 110 is fixed to the upper inner peripheral surface of the nozzle, and the valve 103 is in contact with the valve seat 110. The plunger 102 is biased by a spring 107, and the valve 103 is pressed against the valve seat 110.
[0041]
A stopper 106 made of a C-shaped washer attached to the inside of the valve guide engages with a flange portion 105A formed at the center of the rod 105, so that of the movement of the rod 105 in the arrow direction, The upward movement is restricted.
[0042]
The plunger 102 is inserted into the yoke 114B, and a coil 101 that generates a magnetic force is attached to the outer periphery of the yoke 114B.
[0043]
Further, in the present embodiment, the magnetic film 102A is applied and formed on the outer peripheral portion of the plunger 102, and the magnetic film 114F is also applied and formed on the inner peripheral surface of the yoke 114B facing the magnetic film 102A. ing. Here, the magnetic film 102A and the magnetic film 114F have the same polarity.
[0044]
Since the stopper 106 has the shape of a C-shaped washer, as in the conventional case, the rocking cannot be suppressed in this portion. However, by making the polarities of the magnetic film 102A and the magnetic film 114F the same polarity, Since the jar 102 and the yoke 114B repel each other, the swinging of the plunger can be prevented.
[0045]
According to the present embodiment, by forming a magnetic film having the same polarity on the opposing surfaces of the plunger and the yoke, the inclination of the rod can be suppressed, the life can be extended, and the durability can be improved.
[0046]
Further, by making the shape of the valve hemispherical, the weight can be reduced and the inertia weight can be reduced.
[0047]
Next, a fourth embodiment of the present invention will be described with reference to FIG.
FIG. 8 is a cross-sectional view of a main part of a fuel injection valve for gas according to a fourth embodiment of the present invention.
[0048]
A rod 105 is attached to the tip of the plunger 102. A flange portion 105 </ b> A is formed uniformly at the center of the rod 105. A spherical valve 103 is attached to the tip of the rod 105. The valve 103 is in contact with the valve seat.
[0049]
A stopper 106 made of a C-shaped washer attached to the inside of the valve guide engages with a flange portion 105 </ b> A formed at the center of the rod 105, thereby restricting the upward movement of the valve 110.
[0050]
A ring 112A made of oil-impregnated ceramics is attached to a core 113 that is positioned above the plunger 102 and attached to the yoke. The tip of the ring 112 </ b> A is inserted into a recess at the upper end of the plunger 102.
[0051]
When the plunger 102 moves up and down, the plunger 102 is guided by the ring 112A. By configuring the ring 112A with oil-containing ceramics, it is possible to reduce wear of the ring even if the plunger swings.
[0052]
Further, unlike the embodiment described with reference to FIG. 1 and the like, the ring 112A is configured to be attached to the core 113 at the upper end side. Therefore, when the plunger 102 moves up and down, the upper end side of the plunger 102 slides with the side surface of the ring 112A. In the example of FIG. 1, since the tip of the ring slides on the side surface of the plunger, the wear on the tip of the ring is large. Furthermore, wear of the ring can be reduced.
[0053]
According to the present embodiment, by configuring the ring with oil-impregnated ceramics, wear of the ring can be reduced, life can be extended, and durability can be improved.
[0054]
Further, by attaching the ring to the core side, the wear of the ring can be further reduced, the life can be extended, and the durability can be improved.
[0055]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, durability of the fuel injection valve for gas can be improved.
[0056]
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a gas fuel injection valve according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a main part of a fuel injection valve for gas according to an embodiment of the present invention.
FIG. 3 is a plan view of a stopper of a gas fuel injection valve according to an embodiment of the present invention.
FIG. 4 is a diagram for explaining the wear amount of a ring when a gas fuel injection valve according to an embodiment of the present invention is used.
FIG. 5 is a cross-sectional view of an essential part of a gas fuel injection valve according to another embodiment of the present invention.
FIG. 6 is a plan view of a stopper of a gas fuel injection valve according to another embodiment of the present invention.
FIG. 7 is a cross-sectional view of a main part of a gas fuel injection valve according to a third embodiment of the present invention.
FIG. 8 is a cross-sectional view of a main part of a gas fuel injection valve according to a fourth embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Fuel injection valve 101 ... Coil 102 ... Plunger 103, 103 '... Valve 104 ... Spring receiving part 105 ... Rod 105A ... Flange part 106, 106B, 106C ... Stopper 106A ... Curved surface part 107 ... Spring 108 ... Electrode terminal 109 ... Fuel supply port 110 ... Valve seat 111 ... Nozzle port 112 ... Ring 113 ... Core 114A, 114B, 114C ... Yoke 114D ... Valve guide 114E ... Nozzle

Claims (2)

A valve that contacts the valve seat;
A rod with one end attached to this valve;
A plunger attached to the other end of the rod;
A flange formed at the center of the rod;
A core that is disposed opposite to the plunger and that attracts the plunger by electromagnetic force generated from a coil;
A stopper that engages with the flange portion and restricts movement of the rod when the plunger is sucked by the core;
In the fuel injection valve for gas for sucking the plunger by the core to form a gap between the valve and the valve seat and injecting fuel gas from the gap,
E Bei the rocking motion preventing member for preventing the oscillation of the plunger,
The stopper has a C shape having a notch in a part thereof,
The fuel injection valve for gas , wherein the rocking prevention member is formed by overlapping the two stoppers so that the notch portions face each other . The fuel injection valve for gas according to claim 1,
The swing preventing member includes a first magnetic film formed on the outer peripheral surface of the plunger,
A position opposite to the first magnetic film, which is formed on the inner peripheral surface of the core, and is composed of a second magnetic film having the same polarity as the first magnetic film. Fuel injection valve for gas.

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