JPH09242615A - Fuel injection valve for gaseous fuel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an influence of bound, and execute excellent accurate measurement up to an idle range, in a fuel injection valve for gaseous fuel. SOLUTION: A valve 103 is brought in contact with a valve seat 110, and also attached to a plunger 102 through a rod 105. The plunger 102 is sucked by electromagnetic force generated from a coil 101 so as to form a clearance between the valve 103 and the valve seat 110, and fuel gas is ejected from this clearance. A flange 105A is formed in the center of the rod 105, and when the plunger 102 is sucked by a core 113, a stopper 106 is engaged with the flange 105A so as to regulate the movement of the rod 105. Hereupon, a check valve 117 is arranged in the plunger 102, thereby, when the check valve 117 is opened, the valve 103 is slowly opened, and when the check valve 117 is closed, the valve 103 is pushed to the valve seat 110, so that an influence of bound can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection valve for gaseous fuel, and more particularly to a fuel injection valve for gaseous fuel suitable for use in a fuel injection device for an internal combustion engine for automobiles.

[0002]

2. Description of the Related Art Exhaust gas regulations in recent years are indispensable for the purpose of correcting global environmental damage caused by a vehicle society that depends on petroleum fuel and gasoline. However, in addition to the problems of the supply system and infrastructure, the most prominent alternative fuels for gasoline have many adverse effects on the durability and performance of existing engine components.

Gas fuels such as natural gas and hydrogen gas are in the spotlight as fuels that are friendly to the surrounding environment, and as a future alternative fuel, a high pressure gas fuel CNG (Compressed Nature) obtained by compressing a gas such as natural gas is used.
al Gas) is promising.

In order to supply gaseous fuel to an engine, a fuel injection device for measuring by controlling the opening and closing time width of a fuel injection valve such as an electromagnetic solenoid valve used for conventional liquid fuel such as gasoline is used. Can be used.

As a conventional fuel injection valve for liquid fuel,
For example, the one described in JP-A-63-100261 is known.

[0006]

The relationship between the amount of fuel metered and injected by the fuel injection valve and the valve opening time of the fuel injection valve is usually proportional, but the valve opening time of the fuel injection valve is When the width becomes smaller, due to the effect of bounce when the valve collides with the valve seat, compared to the opening time width of the fuel injection valve,
A large amount of fuel is measured.

In a fuel injection valve for liquid fuel, a region in which the amount of fuel measured is non-linear with respect to the valve opening time width due to the effect of bound is small, so that the valve opening time width with good linearity is generally used. I am trying to use only the area.

However, when various studies have been conducted on the fuel injection valve for gaseous fuel, the region where the measured fuel amount is non-linear with respect to the valve opening time width is larger than that of the liquid fuel injection valve. It turned out. This is because in the injection valve for measuring the gaseous fuel, unlike the case of the liquid fuel, there is no damper effect due to the gaseous fuel, and thus the bound is hard to be attenuated. Therefore, the fuel injection valve for gaseous fuel has a problem that the range in which fuel can be accurately measured is narrow.

Further, as a characteristic of the gas fuel, it can be raised that the energy density is smaller than that of the liquid fuel. That is, the heat generation energy per unit flow rate is small. Therefore, in the fuel injection valve for gaseous fuel, it is necessary to make the valve opening time width of the fuel injection valve to be controlled larger than that of the fuel injection valve for liquid fuel. Since the maximum width of the valve opening time of the fuel injection valve is substantially determined by the relationship with the maximum engine speed, it is necessary to use a region where the valve opening time is short in order to increase the valve opening time width.

However, as described above, in a region where the valve opening time is short, the control accuracy is poor due to the influence of bound. Since the region where the valve opening time is short corresponds to the idle region, there is a problem that the controllability of the idle region is poor when the structure of the conventional fuel injection valve for liquid fuel is directly applied to the fuel injection valve for gas fuel.

It is known that a fuel injection valve (automatic valve) for a diesel engine has a bound effect because the fuel pressure is higher than that of a fuel injection valve for a gasoline engine. As a method of reducing the influence of bound in a fuel injection valve (automatic valve) for a diesel engine, for example, as described in JP-A-6-74130 and JP-A-6-173812, the pressure in the back pressure chamber is reduced. It is known that the relief valve is used for relief.

In these systems, the opening of the fuel injection valve is
Although the valve speed is the same as that of the conventional valve, the valve operates so that it closes slowly when the valve is closed, reducing the impact on the valve and the valve seat when the valve is closed. This method is effective in reducing the effect of bouncing in the region where the valve opening time is long, but as mentioned above, in the injection valve for gaseous fuel, the valve closing speed is slowed in the region where the valve opening time is short. Then, there is a problem that the amount of fuel to be measured increases, and it cannot be applied to a fuel injection valve for gaseous fuel.

Further, as a method of reducing the influence of bound in the fuel injection valve (automatic valve) for another diesel engine, for example, as described in Japanese Utility Model Laid-Open No. 63-86373, the auxiliary hydraulic power source is used. A structure is known in which pressure is guided to a back pressure chamber via a check valve.

In this system, the fuel injection valve is opened at the same valve speed as in the prior art, but when the valve is closed, the valve operates so that it closes earlier to reduce the bounce. However, this method cannot be applied to a fuel injection valve for gaseous fuel.

In a fuel injection valve for a diesel engine, the fuel pressure fluctuates in a pulse shape, and the check valve is opened and closed by utilizing this pulsed fluctuation in fuel pressure. On the other hand, in the fuel injection valve for gaseous fuel, it cannot be changed in a pulsed manner, and the pressure of the fuel needs to be kept constant. This is because gas is a compressible fluid and cannot generate pulsed pressure fluctuations.

An object of the present invention is to provide a fuel injection valve for gaseous fuel, which can reduce the influence of bound and can perform accurate metering even in an idle region.

[0017]

In order to achieve the above object, the present invention provides a valve that abuts a valve seat, a rod having one end attached to the valve, and a plan attached to the other end of the rod. A jar, a flange portion formed in the center of the rod, a core arranged to face the plunger, and attracting the plunger by an electromagnetic force generated from a coil; Has a stopper that engages with the flange portion and regulates the movement of the rod at the time of suctioning, and the core sucks the plunger to form a gap between the valve and the valve seat. In a fuel injection valve for gaseous fuel that injects fuel gas through a gap, the plunger penetrates the fuel gas from upstream to downstream. The pressure adjusting means for increasing the pressure on the upstream side of the plunger as compared with the pressure on the downstream side when the valve is closed is provided on the passage. At times, the valve can be opened slowly, and when it is closed quickly, the valve can be pressed against the valve seat to reduce the effect of bounce.

In the above-mentioned fuel injection valve for gaseous fuel, preferably, the pressure adjusting means is a check valve arranged to be pressed so as to close the passage of the plunger from the downstream side toward the upstream side.

In the fuel injection valve for gaseous fuel, preferably, the pressure adjusting means is arranged so as to be biased by a spring force so as to close the passage of the plunger from the downstream side toward the upstream side. It is a reed valve.

In the above-mentioned fuel injection valve for gaseous fuel, preferably, the diameter of the passage is such that the pressure difference across the passage is 0.33 kg / cm ² or less.

In order to achieve the above object, the present invention provides a valve that abuts a valve seat, a rod having one end attached to the valve, a plunger attached to the other end of the rod, A flange portion formed in the central portion of the rod, a core arranged to face the plunger and attracting the plunger by an electromagnetic force generated from a coil, and at the time of attraction of the plunger by the core, A stopper is provided to engage with the flange portion to restrict the movement of the rod, and the core sucks the plunger to form a gap between the valve and the valve seat. In the fuel injection valve for injecting gaseous fuel, a passage for supplying gaseous fuel is provided on the side of the rod, and the plunger is Is obtained by so as to movable encapsulated space of the liquid, by adopting such a configuration,
The effect of bounce can be reduced without causing sudden valve closing.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION A fuel injection valve for gaseous fuel according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 5. FIG. 1 is an overall configuration diagram of an engine control system using a fuel injection valve for gaseous fuel according to an embodiment of the present invention.

Each cylinder of the multi-cylinder engine 1 has a combustion chamber (cylinder) 4 composed of a piston 2 and a cylinder 3. An intake valve 5 and an exhaust valve 6 are attached to the combustion chamber 4, and the air-fuel mixture introduced into the combustion chamber 4 is ignited by an ignition plug 7. Further, in the vicinity of the intake valve 5 of each cylinder of the engine 1, a fuel injection valve 100 that outputs a command from the controller 15 to measure and inject gaseous fuel is mounted. The gaseous fuel is the fuel injection valve 10
By 0, it is indirectly supplied to each cylinder at the optimum timing. As the gaseous fuel, the gaseous fuel such as CNG in the fuel tank 28 is adjusted to a constant fuel pressure by the fuel pressure regulator 26 and supplied.

The throttle valve 11 arranged in the intake pipe 9 rotates in response to the movement of an accelerator pedal (not shown), and the opening degree of the throttle valve 11 is detected by the throttle valve angle sensor 23. The signal from the throttle valve angle sensor 23 is input to the overall calculation unit 17 of the controller 15. The comprehensive calculation unit 17 calculates based on the input throttle opening and estimates the load on the engine 1.

The signal of the crank angle sensor 12 is input to the general calculation section 17 of the controller 15. The general calculation unit 17 calculates the rotation speed of the engine 1 based on the input signal from the crank angle sensor 12. Also, the intake pipe 9
Air flow sensor (H / W sensor)
The signal of 8 and the signal of the oxygen concentration sensor 14 which estimates the air-fuel ratio from the oxygen concentration in the exhaust pipe 13 are taken into the air-fuel ratio arithmetic circuit 16 of the controller 15, and the air-fuel ratio is arithmetically processed.

The comprehensive calculation unit 17 takes in the air-fuel ratio calculated by the air-fuel ratio calculation circuit 16 and issues a command to the fuel injection device command circuit 18, the ignition device command circuit 19 and the EGR device command circuit 20. The fuel injection device command circuit 18 receives the fuel injection valve 100 based on the command from the overall calculation unit 17.
To optimally control the fuel injection amount from. The ignition device command circuit 19 optimally controls the ignition timing of the spark plug 7 on the basis of a command from the overall calculation unit 17. The EGR device command circuit 20 optimally controls the recirculation amount of the exhaust gas through the EGR valve 24 based on the command from the general calculation unit 17.

Further, the exhaust gas discharged from the engine 1 is discharged to the outside air from the exhaust table pipe 22 via the catalyst device 21 installed on the way of the exhaust pipe 13. When the engine is started, the catalyst device 21 cannot be sufficiently warmed up and is not activated, so that harmful exhaust components such as HC and CO are hard to be purified.

After the engine is warmed up, the controller 15 controls the amount of gaseous fuel based on the signal from the oxygen concentration sensor 14 to maintain the catalyst conversion efficiency.
Ignition timing is controlled. Furthermore, since the combustion temperature rises, a large amount of nitrogen oxides (NOx) is emitted, so H
/ W Sensor8 signal and intake pipe pressure sensor 25
Based on a signal such as the above, the opening area of the EGR valve 24 is controlled and measured by the EGR device drive circuit 20 of the controller 15, a part of the exhaust gas is recirculated into the intake pipe 9, and based on the burned gas mixing effect. , The combustion temperature is lowered, and the NOx emission amount is reduced.

An intake pipe pressure sensor 25 for measuring the pressure inside the intake pipe is installed in the intake pipe 9. Pressure sensor 2
In addition to estimating the EGR rate, 5 is used to estimate the air filling rate in the intake pipe at the time of engine start and supply appropriate fuel to each cylinder.

A battery 27 is connected to the controller 15 and is supplied with a voltage.

Next, the structure of the fuel injection valve for gaseous fuel according to the embodiment of the present invention will be described with reference to FIG. FIG. 2 is a sectional view of a fuel injection valve for gaseous fuel according to an embodiment of the present invention.

The yoke of the fuel injection valve 100 is the yoke 11
4A, 114B, 114C. The yoke 114B is fitted inside the yoke 114C,
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 101 is fixed by a yoke 114A.
The coil 101 is energized via the electrode terminal 108 attached to 14A. A valve guide 114D is attached to the tip of the yoke 114C. York 114
Plunger 102 is arranged inside B.

At the tip of the plunger 102, the rod 1
05 is attached. A flange portion 105A is integrally formed at the central 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 a rod 105. A ring-shaped valve seat 110 is fixed to the inner peripheral surface below the valve guide 114D, and the valve 103 is in contact with the valve seat 110.

A cylindrical ring 112 is fixed to the upper surface of the plunger 102. Also, the yoke 114B
A core 113 is fixed to the inner circumference of the. Ring 11
2 is slidably inserted into the inner circumference of the core 113. The ring 112 slides on the inner peripheral surface of the core 113, whereby the plunger 102 and the rod 1 forming the valve body.
05 and the valve 103 in the axial direction.

A cylindrical spring receiving member 104 is fixed to the inner circumference of the yoke 114A. A spring 107 is arranged between the spring receiving member 104 and the plunger 102, and presses the plunger 102 downward. Therefore, normally, the spring 107
The valve 103 is pressed against the valve seat 110 by the downward pressing force of the valve 103.

When the coil 101 is energized and a predetermined current is supplied through the electrode terminal 108, an electromagnetic force is generated in the coil 101, and the plunger 102 is moved upward against the spring force of the spring 107. Attracted, a gap is created between the valve 103 and the valve seat 110.
Inside the valve guide 114D, a stopper 106 having the shape of a C-shaped washer is attached, and by engaging with a flange portion 105A formed in the central portion of the rod 105, the valve 110 moves upward, That is, the lift amount of the valve 103 is regulated.

Fuel supply port 10 above the fuel injection valve 100
From 9, gas fuel such as natural gas is supplied,
Nozzle port through the hole formed in the center of the spring receiving member 104, the inside of the ring-shaped core 113, the passage 115 formed in the plunger 102, and the gap formed between the valve 103 and the valve seat 110. It is jetted from 111.

Here, the passage 115 is provided with a check valve 117 pressed by a spring 116. When the fuel injection valve is opened, the plunger 102 is pulled upward, and the pressure above the plunger 102 becomes higher than the pressure below, so that the gaseous fuel pushes the check valve 117 and moves downstream from the passage 115. leak. Further, when the fuel injection valve is closed, the plunger 102 is lowered and the check valve 117 is closed.

The pressure of the gaseous fuel supplied is, for example, 4
a kg / cm ^2, then the spring pressure of the spring 116 is set to 10 kg / cm ^2.

Next, with reference to FIG. 3, the operation when the plunger is raised and lowered will be described. 3A and 3B are operation explanatory views of the fuel injection valve for gaseous fuel according to the embodiment of the present invention, FIG. 3A is a waveform diagram of a voltage applied to the core 101, and FIG. 3B is a plunger 102. 3C is a diagram showing the upstream pressure and the downstream pressure of FIG. 3C, and FIG.

As shown in FIG. 3A, at time T10, a voltage for opening the valve is applied to the core 101 of the fuel injection valve 100. The plunger 102 is attracted by the electromagnetic force generated in the core 101 and pulled upward.
When the pressure of the gaseous fuel applied to the check valve 117 becomes higher than the spring pressure of the spring 116, the check valve 117
And the gaseous fuel passes through the passage 115 to the valve 10
3 and the valve seat 110 through a gap formed between the nozzle seat 111 and the nozzle port 111.

At this time, looking at the pressures on the upstream side and the downstream side of the plunger 102, as shown in FIG. 3 (B),
The upstream pressure PU is the fuel pressure flowing from the fuel supply port 109, which is equal to the fuel pressure adjusted by the fuel pressure regulator 26 and is a constant pressure. On the other hand, the downstream pressure PL is reduced by the pressure loss of the check valve 117.

If there is no check valve, the pressure on the upstream side of the plunger and the pressure on the downstream side are equal,
As shown by the broken line in (C), at the time T11, the valve 10
3 is raised to the maximum lift position. However, the flange portion 10 formed in the central portion of the rod 105
5A collides with the stopper 106, and the lift amount of the valve 103 fluctuates.
Occurs.

On the other hand, by providing the check valve 117, the plunger 102 is pulled up against the pressure of the gaseous fuel, so that its movement becomes slower than in the case without the check valve. That is, FIG.
As shown by the solid line in (C), at the time T12, the valve 103
Is lifted to the maximum lift position.

As shown in FIG. 3A, at time T20, the voltage application to the core 101 of the fuel injection valve 100 is stopped due to the valve closing. Plunger 102 is core 101
Since the electromagnetic force generated by is eliminated, it is pressed downward by the spring 107. At this time, check valve 11
7 remains closed.

Looking at the pressures on the upstream side and the downstream side of the plunger 102, as shown in FIG. 3 (B),
The upstream pressure PU is the fuel pressure flowing from the fuel supply port 109, which is equal to the fuel pressure adjusted by the fuel pressure regulator 26 and is a constant pressure. On the other hand, the downstream pressure PL is reduced by the pressure loss of the check valve 117. That is, when the valve 103 is closed, the pressure PU on the upstream side of the plunger 102 is higher than the pressure PL on the downstream side. Since the check valve 117 remains closed, as the plunger 102 descends, the gaseous fuel on the downstream side of the plunger 102 flows out from the gap between the plunger 102 and the yoke 114C to the upstream side of the plunger 102, and finally. Specifically, the pressures on the upstream side and the downstream side of the plunger 102 become equal.

If there is no check valve, the pressure on the upstream side of the plunger is equal to the pressure on the downstream side,
As shown by the broken line in (C), the valve lowering starts at time T21, and the valve 103 closes at time T23. However, when the valve 103 collides with the valve seat 110, a bouncing Bo-d is generated when the valve 103 lifts, which varies.

On the other hand, by providing the check valve 117, the pressure on the upstream side of the plunger 102 becomes high, so that a force acts by pressing the valve 103 against the valve seat 110, and its movement is caused by the check valve. It will be faster than it would be without it. That is, as indicated by the solid line in FIG. 3C, the valve 103 is closed at time T22. Since the valve 103 is pressed against the valve seat 110, the bounce can be suppressed.

The bounce phenomenon is more likely to occur when the valve is closed than when the valve is opened. The reason is that, in general, a fuel injection valve often injects vertically downward, as shown in FIG. 1, and therefore, when the valve is closed, the acceleration of gravity is superimposed on the downward movement of the valve. Is. However, by providing the check valve 117, the valve can be pressed against the valve seat to suppress the bounce due to the bounce and reduce the bounce.

Next, the relationship between the valve opening time of the fuel injection valve and the fuel injection amount per injection will be described with reference to FIG.
FIG. 4 is a diagram showing fuel injection characteristics of the fuel injection valve for gaseous fuel according to the embodiment of the present invention.

In FIG. 4, the horizontal axis represents the valve opening time T of the fuel injection valve. Here, the valve opening time is the time when the voltage is applied to the fuel injection valve, and is the time corresponding to the time (T20-T10) in FIG. The vertical axis represents the fuel injection amount in one injection, which is the amount actually injected from the nozzle port 111 of the fuel injection valve.

In FIG. 4, a solid line GI shows the relationship between the valve opening time of the fuel injection valve and the fuel injection amount per injection in the fuel injection valve for gaseous fuel having the check valve according to the embodiment of the present invention. And the linearity of both is good.

In FIG. 4, the broken line L represents the characteristic of the conventional fuel injection valve for liquid fuel. In the region where the valve opening time is shorter than the time T1, the characteristics show a characteristic that the fuel injection amount increases even though the valve opening time T becomes shorter than the linear range. This is caused by the effects of bounds.

Here, the maximum valve opening time T3 of the fuel injection valve
Is, for example, 5 ms, the valve opening time T1 in the non-linear region in the fuel injection valve for liquid fuel is, for example,
It is 1.5 ms. Therefore, in the control of the fuel injection amount using the fuel injection valve for liquid fuel, it is general to use the valve opening time T within the range of good linearity from time T1 to time T3. As described in JP-A-6-74130 and JP-A-6-173812, the opening of the fuel injection valve is the same as the conventional one, as in the system in which the pressure in the back pressure chamber is relieved by the relief valve. It is the speed of the valve, but when the valve operation is such that it closes slowly when the valve is closed, and the method of reducing the impact of the valve and the valve seat when the valve is closed is adopted, the characteristic of the broken line L is the characteristic of the solid line GI. However, due to the effect of slowing the valve closing time, the characteristics are lost on the side where the valve opening time is short, and the controllability of the idle region for gaseous fuel cannot be improved.

On the other hand, the characteristic of the fuel injection valve for gas fuel of the type that does not use a check valve is that the chain line Gp
Is shown in. That is, in the region where the valve opening time is shorter than the time T2, the characteristic deviates from the linear range,
Although the valve opening time T is shortened, the fuel injection amount increases. This is an effect of the bounds Bo-u and Bo-d shown by broken lines in FIG.

Moreover, as compared with the range (T0 to T1) showing the non-linearity of the fuel injection valve for liquid fuel shown by the broken line, the range (T0 to T2) showing the non-linearity of the fuel injection valve for gaseous fuel. Is getting wider. For example, T2 is 2 ms. The reason why the range of non-linearity is wide is that unlike the case of liquid fuel, there is no damper effect due to gas fuel, and thus the bound is difficult to attenuate. Therefore, in the fuel injection valve for gaseous fuel, the range in which fuel can be accurately measured (T2 to T3) is narrower than that of the fuel injection valve for liquid fuel.

Further, as a characteristic of the gas fuel, there is a point that the energy density is smaller than that of the liquid fuel, that is, the heat generation energy per unit flow rate is smaller. Therefore, in the fuel injection valve for gaseous fuel, it is necessary to make the valve opening time width of the fuel injection valve to be controlled larger than that of the fuel injection valve for liquid fuel. Since the maximum width T3 of the valve opening time of the fuel injection valve is substantially determined by the relationship with the maximum engine speed, it is necessary to use a region where the valve opening time is short in order to increase the valve opening time width. However, as described above, the control accuracy is poor in the region where the valve opening time is short (T0 to T2) due to the influence of bound. Since the region where the valve opening time is short corresponds to the idle region, the controllability of the idle region is poor when the fuel injection valve for gaseous fuel having the characteristics shown by the alternate long and short dash line is used.

On the other hand, by using the check valve as in the present embodiment, the straight line is improved and the metering accuracy is improved in a wide valve opening time range, and the engine control using the gaseous fuel is improved. Also in the above, the controllability in a wide range including the idle region is improved.

The passage 115 closed by the check valve 117 is constructed so that it opens when the plunger 102 moves up and closes when it moves down. Passage 115
When is closed, the flow path of the gaseous fuel from the upstream side to the downstream side of the plunger 102 is only the gap between the plunger 102 and the yoke 114C. Since this gap is small, the flow path resistance is large, and in particular, the flow path resistance may increase as the fuel injection amount of the large-sized fuel injection valve increases. This increase in flow path resistance is due to the plunger 10
The pulling speed is decreased by 2, that is, a delay of the time T12 in FIG.

Therefore, in order to eliminate this delay,
As shown by the broken line in FIG. 2, a main passage 115 ′ that is always open is provided on the bottom surface of the plunger 102 so that the gaseous fuel can flow between the upstream side and the downstream side of the plunger 102. Good. As described above, the check valve 117 operates so as to open when the plunger 102 moves up and close when it moves down.

Next, the diameter of the passage provided in the plunger will be described with reference to FIG. FIG. 5 is a diagram schematically showing a fuel injection valve according to an embodiment of the present invention.

The structure of the fuel injection valve is as follows: the first orifice O1 formed by the passages 115, 115 'when the check valve 117 shown in FIG.
And a second orifice O2 formed between the valve seat 110 and two orifices having different diameters are connected in series. On the upstream side of the plunger,
Gas fuel with a constant pressure is supplied. When the check valve is opened, an orifice O1 having a predetermined diameter is formed in the plunger portion as a flow path for the gaseous fuel. At this time, the orifice O2 of the nozzle portion of the injection valve is also opened, and the orifice O1 and the orifice O2 are also opened.
The opening area of is important.

Generally, when gas is injected through an orifice, the differential pressure across the orifice is 0.33 kg / c.
With m ² , the gas flowing through it reaches the speed of sound, and the gas flow rate is a constant amount that depends only on the orifice diameter.
In a fuel injection valve for automobiles, the diameter of the orifice O2 is usually 0.3 mm to 0.5 mm.
Since it is extremely small for the diameter of 1 (1 to 2 mm), the gas flow rate is determined by the diameter of the orifice 02.

On the other hand, regarding the orifice O1 formed by the passage portion of the plunger, this orifice O1
It is necessary to set the flow velocity of the gas flowing through to below the speed of sound. Therefore, the diameter of the orifice O1 should be such that the pressure difference before and after the orifice O1 is 0.33 kg / cm ² or less.

According to the present embodiment, by using the check valve, the pulling-up speed of the plunger is slowed when the valve is opened, and the plunger is pressed against the valve seed when the valve is closed, so that the bound is prevented. The influence is reduced and the straight line is improved in a wide valve opening time range.
Weighing accuracy is improved. Therefore, also in the control of the engine using the gaseous fuel, the controllability in a wide range including the idle region is improved.

Further, by adopting the check valve system, the durability is improved even when the valve is repeatedly opened and closed as the plunger moves up and down.

Further, without using a back pressure chamber or an auxiliary pressure source, it is possible to reduce the effect of a simple bounce of providing a check valve in a part of the fuel passage.

Next, the structure of the fuel injection valve for gaseous fuel according to another embodiment of the present invention will be described with reference to FIG. FIG. 6 is a sectional view of a main part of a fuel injection valve for a gaseous fuel according to another embodiment of the present invention.

The rod 1 is attached to the tip of the plunger 102.
05 is attached. A flange portion 105A is integrally formed at the central portion 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 valve guide 114D, and the valve 103 is in contact with the valve seat 110.

The passage 11 formed in the plunger 102
A reed valve 118 is attached to the outlet on the downstream side of 5. When the fuel injection valve is opened, the plunger 1
02 is pulled upward, and the pressure above the plunger 102 becomes higher than the pressure below, so that the gaseous fuel is
The reed valve 118 is pushed away and flows out from the passage 115 downstream. Further, when the fuel injection valve is closed, the plunger 102 is lowered and the reed valve 118 is closed.

When the injection valve is opened and the upstream pressure hits the reed valve 118 through the passage 115, the reed valve 118 is pushed away to push the gas downstream, and the gas is ejected from the nozzle port 111 to the outside. By providing the reed valve 118, the plunger 102 is pulled up against the pressure of the gaseous fuel, so that its movement is slower than it would be without the reed valve.

When the injection valve is closed, the pressure on the downstream side of the reed valve 118 is decreased by the pressure loss and the pressure on the upstream side of the plunger 102 is increased as in the above-described check valve. Rebound will be suppressed because the pushing force increases downward. Further, by providing the reed valve 118, the pressure on the upstream side of the plunger 102 becomes high, so that the valve 10
The force acts by pressing 3 against the valve seat 110,
The movement is faster than it would be without the check valve. Since the valve 103 is pressed against the valve seat 110, the bounce due to the bounce can be suppressed and the bounce can be reduced.

The weight of the plunger portion including the plunger 102, the rod 105 and the valve 103 is 5 to 6
g. The weight of the reed valve 118 is 0.4.
Since it is about g, even if the reed valve is attached to the plunger, the weight can be reduced compared to the case where the check valve is used as shown in the example of FIG. Therefore, the driving speed of the fuel injection valve can be improved.

According to the present embodiment, by using the reed valve, the pull-up speed of the plunger is slowed when the valve is opened, and the plunger is pressed against the valve seed when the valve is closed, so that the bound is prevented. By reducing the influence, the straight line is improved and the measurement accuracy is improved in a wide valve opening time range. Therefore, also in the control of the engine using the gaseous fuel, the controllability in a wide range including the idle region is improved.

Further, by adopting the reed valve system, the inertial weight of the plunger can be reduced and the injection valve can be driven at high speed.

Further, without using a back pressure chamber or an auxiliary pressure source, it is possible to reduce the effect of a simple bounce of providing a check valve in a part of the fuel passage.

Next, the structure of the fuel injection valve for gaseous fuel according to another embodiment of the present invention will be described with reference to FIG. FIG. 7 is a sectional view of a main part of a fuel injection valve for gaseous fuel according to another embodiment of the present invention. 2 that are the same as those in FIG. 2 have the same function.

In the present embodiment, the gaseous fuel does not flow from above the fuel injection valve but from the side surface of the fuel injection valve. In addition, the movable part of the plunger is liquid-sealed.

Inside the yoke 114 of the fuel injection valve 100, the coil 101 for electromagnetic generation is fixed. The upper surface of the coil 101 is fixed by a yoke 114, and the coil 101 is energized via an electrode terminal 108 attached to the yoke 114. A valve guide 114D is attached to the tip of the yoke 114. The plunger 102 is arranged inside the yoke 114.

The rod 1 is attached to the tip of the plunger 102.
05 is attached. A flange portion 105A is integrally formed at the central 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 a rod 105. A ring-shaped valve seat 110 is fixed to the inner peripheral surface below the valve guide 114D, and the valve 103 is in contact with the valve seat 110. The core 113 is fixed to the inner circumference of the yoke 114.

A disc-shaped spring receiving member 104A is fixed to the upper surface of the yoke 114. A spring 107 is arranged between the spring receiving member 104A and the plunger 102, and presses the plunger 102 downward. Therefore, normally, the spring 10
The valve 103 is pressed against the valve seat 110 by the downward pressing force of 7.

When the coil 101 is energized and a predetermined current is supplied through the electrode terminal 108, an electromagnetic force is generated in the coil 101, and the plunger 102 is moved upward against the spring force of the spring 107. Attracted, a gap is created between the valve 103 and the valve seat 110.
Inside the valve guide 114D, a stopper 106 having the shape of a C-shaped washer is attached, and by engaging with a flange portion 105A formed in the central portion of the rod 105, the valve 110 moves upward, That is, the lift amount of the valve 103 is regulated.

The fuel supply port 10 on the side of the fuel injection valve 100
A gaseous fuel such as natural gas, which is a fuel, is supplied from 9A and is injected from a nozzle port 111 through a gap formed between the valve 103 and the valve seat 110.

Here, a liquid 119 is enclosed in the movable part of the plunger 102, and this liquid 119 is
When the valve 103 is opened, the liquid 119 that has not been sealed up to the entire height of the plunger 102 is contained in the liquid passage 115A of the plunger 102.
There is almost no resistance and it opens smoothly. However, when the valve is closed, the liquid 119 is trapped between the lower portion of the plunger 102 and the injection valve casing 120, so that the valve does not suddenly close and the rebound of the valve is eliminated. That is, when the valve is opened, the valve is slowly opened, and when the valve is closed, the valve is slowly closed. In addition, the yoke 1
A sealing member 121 is interposed between the rod 14 and the rod 105 to prevent leakage of the enclosed liquid 119.

According to the present embodiment, even in a fuel injection valve of the type in which gaseous fuel is supplied from the side of the fuel injection valve, the influence of bound is reduced, and a straight line is obtained in a wide valve opening time range. It is possible to improve the measurement accuracy.

[0086]

According to the present invention, the influence of bouncing in the fuel injection valve for gaseous fuel can be reduced, and accurate metering can be performed even in the idle region.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an engine control system using a fuel injection valve for gaseous fuel according to an embodiment of the present invention.

FIG. 2 is a sectional view of a fuel injection valve for gaseous fuel according to an embodiment of the present invention.

3A and 3B are operation explanatory diagrams of the fuel injection valve for gaseous fuel according to the embodiment of the present invention, FIG. 3A is a waveform diagram of a voltage applied to the core 101, and FIG.
It is a figure which shows the upstream pressure and downstream pressure of FIG.
It is a figure showing the lift amount of 03.

FIG. 4 is a diagram showing fuel injection characteristics of a fuel injection valve for gaseous fuel according to an embodiment of the present invention.

FIG. 5 is a diagram schematically showing a fuel injection valve according to an embodiment of the present invention.

FIG. 6 is a cross-sectional view of a main part of a fuel injection valve for gaseous fuel according to another embodiment of the present invention.

FIG. 7 is a sectional view of an essential part of a fuel injection valve for gaseous fuel according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Piston 3 ... Cylinder 4 ... Combustion chamber 5 ... Intake valve 6 ... Exhaust valve 7 ... Spark plug 8 ... H / W sensor 9 ... Intake pipe 10 ... Fuel injection valve 11 ... Throttle valve 12 ... Crank angle sensor 13 Exhaust pipe 14 Oxygen concentration sensor 15 Controller 100 Fuel injection valve 101 Coil 102 Plunger 103 Valve 104 Spring receiving portion 105 Rod 105A Flange 106, 106A Stopper 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 115,115 '... Hole 116 ... Spring 117 ... Check valve 118 ... Reed valve 119 ... Liquid 121 ... Sealing member

Claims (5)

[Claims] 1. A valve that comes into contact with a valve seat, a rod having one end attached to the valve, a plunger attached to the other end of the rod, and a flange portion formed at the center of the rod. A core arranged to face the plunger and sucking the plunger by an electromagnetic force generated by a coil, and a rod moving by engaging the flange portion when the plunger sucks the plunger. In the fuel injection valve for gaseous fuel, which has a stopper for regulating the above-mentioned, the core sucks the plunger to form a gap between the valve and the valve seat, and injects fuel gas from the gap, The plunger is located on the passage through which the fuel gas passes from the upstream side to the downstream side, and when the valve is closed, the upstream side of the plunger. Gaseous fuel for a fuel injection valve, wherein a pressure with a pressure regulating means is larger than the pressure downstream of the. 2. The fuel injection valve for a gaseous fuel according to claim 1, wherein the pressure adjusting means is a check valve arranged to be pressed so as to close the passage of the plunger from the downstream side toward the upstream side. A fuel injection valve for gaseous fuel, characterized by: 3. The fuel injection valve for gaseous fuel according to claim 1, wherein the pressure adjusting means is biased by a spring force so as to close the passage of the plunger from the downstream side toward the upstream side. A fuel injection valve for gaseous fuel, which is a reed valve arranged. 4. The fuel injection valve for a gaseous fuel according to claim 1, wherein the diameter of the passage has a pressure difference of 0.3 before and after the passage.
A fuel injection valve for gaseous fuel, which has a diameter of 3 kg / cm ² or less. 5. A valve that comes into contact with a valve seat, a rod having one end attached to the valve, a plunger attached to the other end of the rod, and a flange portion formed at the center of the rod. A core arranged to face the plunger and sucking the plunger by an electromagnetic force generated by a coil, and a rod moving by engaging the flange portion when the plunger sucks the plunger. In the fuel injection valve for gas fuel, which has a stopper for regulating the above-mentioned, the core sucks the plunger to form a gap between the valve and the valve seat, and injects the fuel gas from the gap, A passage for supplying fuel is provided on the side of the rod, and the plunger is movable in a space filled with liquid. Gaseous fuel for a fuel injection valve according to claim.