JPH06249098A - Fuel injection valve - Google Patents

Abstract

PURPOSE:To prevent an occurrence of black smoke and reduce the emission of harmful exhaust such as NOx. CONSTITUTION:An actuator 112 is moved at high cycles, and the movement of the actuator 112 is transmitted to a needle valve 11 via a push-rod 111 and a spring shoe 12, so that the needle valve 11 is moved also at high cycles. As a result, injection pressure of the fuel from an injection hole 18 is varied, while the size and length of the atomized fuel is also varied. Thus, mixing of the atomized fuel and the surrounding air is accelerated, thereby giving a good mixture.

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 an internal combustion engine.

[0002]

2. Description of the Related Art Since a diesel engine has high thermal efficiency,
Widely used as a prime mover. But exhaust black smoke, N
Since a lot of harmful substances such as Ox and HC are emitted, these measures must be taken. A diesel engine compresses air into high temperature and high pressure by a piston, injects high pressure fuel into it, ignites and burns it, thereby generating heat,
Producing power, but good combustion can reduce the harmful emissions. In order to perform this combustion favorably, it is necessary to improve the mixing of the injected fuel and air.

A conventional example of the fuel injection device used at this time will be described with reference to FIG. 4. Reference numeral 1 is a fuel injection valve, which has a nozzle body 10 and inside the nozzle body 10. The needle valve 11 is slidably fitted and kept in an oil-tight state, and the spring receiver 12 provided on the upper portion of the needle valve 11 and the nozzle body 1
0 is provided between the upper part of the spring chamber wall 14 and the upper part of the spring chamber wall 14
The needle valve 11 is urged in the valve closing direction.

Reference numeral 15 is an oil passage that penetrates the spring chamber wall 14 in the vertical direction, and 16 is an oil passage that penetrates the nozzle body 10 in the vertical direction, and these oil passages 15 and 16 communicate with each other.
17 is an oil sump provided in the lower portion of the nozzle body 10;
Reference numeral 8 denotes an injection hole provided at the lower end of the nozzle body 10. Two
Is a fuel pump, 21 is a plunger, 22 is a cylinder,
The plunger 21 slides in the cylinder 22. 23 is a discharge valve casing provided in the upper part of the cylinder 22, 24 is a plunger chamber formed in the plunger 21, 25 is a discharge valve in the discharge valve casing 23, and the discharge valve 25
Is urged in the valve closing direction by a spring. 26 is a notch lead provided in the plunger 21, 27 is an oil supply / drain hole penetrating the wall of the cylinder 22, 31 is a fuel supply pipe communicating with the same oil supply / drain hole 27, 32 is a discharge valve casing 23 of the fuel pump 2. It is an injection pipe that communicates the inside with the oil passage 15 of the combustion injection valve 1.

In the fuel injection device shown in FIG. 4, the plunger 21 of the fuel pump 2 is moved up and down by a cam (not shown), and the oil supply / discharge hole 27 is opened and closed by the upper portion of the plunger 21. When the plunger 21 rises, the plunger chamber 24
The inside becomes high pressure, the discharge valve 25 is pushed open against the spring, and the system of the injection pipe 32 → oil passage 15 → oil passage 16 → oil sump 17 becomes high pressure.

When the pressure in the oil sump 17 becomes higher than the closing pressure of the needle valve 11, the needle valve 11 rises against the spring 13, the injection hole 18 is opened, and fuel is injected from the injection hole 18. . When the required amount of injection is performed, the notch lead 26 of the plunger 21 faces the oil supply / drain hole 27, the plunger chamber 24 communicates with the oil supply / drain hole 27 via the notch lead 26, and the injection pipe 32 → The system of oil passage 15 → oil passage 16 → oil sump 17 becomes low pressure, the needle valve 11 is lowered by the spring 13, and the injection hole 18 is closed. The above actions are repeated thereafter.

FIG. 5 shows the relationship between the injection pressure, the needle valve lift and the crank angle, and FIG. 6 shows the state in which the fuel is atomized at a substantially constant pressure during the injection period.

[0008]

In the conventional fuel injection device shown in FIG. 4, the fuel is continuously injected from the injection holes 18 to be atomized, and the atomized fuel in the peripheral portion entrains the surrounding air. While mixing (see the arrow in FIG. 6) with air, the atomized fuel in the peripheral portion burns in a good state at the time of ignition,
The central part of the atomized fuel remains in a liquid state because of continuous injection, and mixing with air is poor, resulting in lack of air (low excess air ratio) and generation of black smoke. .
Further, in the transition region between the peripheral portion and the central portion of the atomized fuel, there is a problem that an equivalence ratio portion is generated and NOx generation is increased.

The present invention is proposed in view of the above problems, and the object thereof is to prevent generation of black smoke. Another point is to provide a fuel injection valve that can reduce the emission of harmful emissions such as NOx.

[0010]

In order to achieve the above object, a combustion injection valve according to the present invention is provided with an actuator that is displaced at a high cycle at the upper part of a needle valve of the fuel injection valve, and the movement of the actuator. Is transmitted to the needle valve via a push rod and a spring receiver to periodically change the displacement amount of the needle valve.

[0011]

The fuel injection valve of the present invention is configured as described above, and while displacing the actuator in a high cycle, the movement of the actuator is transmitted to the needle valve via the push rod and the spring receiver, and The amount of displacement is changed with a high cycle, the injection pressure of the fuel from the injection hole is changed, the size and length of the spray fuel are changed, and the mixing of the spray fuel and the air in the surrounding area is promoted. Get a mixture.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a fuel injection valve of the present invention will be described with reference to an embodiment shown in FIG. 1. Reference numeral 101 is a fuel injection valve, and the fuel injection valve 101 has a nozzle body 10 and the nozzle body 1
A needle valve 11 is slidably fitted in the valve 0 while keeping an oil-tight state, and is interposed between a spring receiver 12 provided on the upper part of the needle valve 11 and an upper part of a spring chamber wall 14 provided on the upper part of the nozzle body 10. Spring 1
3, the needle valve 11 is urged in the valve closing direction.

Reference numeral 113 is an actuator chamber wall provided above the spring chamber wall 14, and 112 is the actuator chamber wall 1.
Actuator housed in 13 and displaced at high cycle, 1
Reference numeral 11 is a push rod that penetrates the spring chamber wall 14 and supports the actuator 112. A spring 114 is interposed between the upper portion of the push rod 111 and the upper portion of the spring chamber wall 14 to push the push rod 111 and the actuator 112. And are urged upward.

A piezoelectric element, a magnetostrictive element, or the like is used for the actuator 112. The gap L between the upper surface of the spring receiver 12 and the lower end surface of the push rod 111 is equal to the maximum lift amount L of the needle valve 11. 15 is the spring chamber wall 14
An oil passage penetrating in the vertical direction, and 16 is the nozzle body 10
Is an oil passage that penetrates the actuator chamber wall 113 in the vertical direction, and these oil passages 15, 16, 115 are in communication with each other. Reference numeral 17 is an oil sump provided in the lower portion of the nozzle body 10, and 18 is an injection hole provided in the lower end portion of the nozzle body 10.

2 is a fuel pump, 21 is a plunger, 22
Is a cylinder, and the plunger 21 slides in the cylinder 22. 23 is a discharge valve casing provided in the upper part of the cylinder 22, 24 is a plunger chamber formed in the plunger 21, 25 is a discharge valve in the discharge valve casing 23, and the discharge valve 25 is closed by a spring. Being energized. 26 is a notch lead provided on the plunger 21;
Reference numeral 7 denotes an oil supply / exhaust hole penetrating the wall of the cylinder 22, 31 denotes a fuel supply pipe communicating with the same oil supply / exhaust hole 27, 32 denotes the inside of the discharge valve casing 23 of the fuel pump 2 and the oil passage 115 of the combustion injection valve 101. Is a driver for driving the actuator 112, and 302 is a controller of the driver 301.

Next, the operation of the fuel injection valve shown in FIG. 1 will be specifically described. The plunger 21 of the fuel pump 2 moves up and down by a cam (not shown), and the oil supply / drain hole 27 is opened and closed by the upper portion of the plunger 21. When the plunger 21 rises, the pressure inside the plunger chamber 24 becomes high, the discharge valve 25 is pushed open against the spring, and the system of the injection pipe 32 → oil passage 15 → oil passage 16 → oil sump 17 becomes high pressure.

When the pressure in the oil sump 17 becomes higher than the closing pressure of the needle valve 11, the needle valve 11 rises against the spring 13, the injection hole 18 is opened, and the fuel is injected from the injection hole 18. . On the other hand, when the needle valve 11 rises, the upper surface of the spring bridge 12 is
It contacts the lower end surface of 11. At this time, the controller 30
In response to a command from 2, the driver 301 operates, the actuator 112 is displaced downward, and the needle valve 11 is lowered in the closing direction via the push rod 111 and the spring receiver 12, but the pump accompanying the lowering of the needle valve 11 Due to the action, the injection pressure of the fuel from the injection hole 18 increases.

After a minute time has passed, the command from the controller 302 to the driver 301 is turned off, the actuator 112 is displaced upward, and the needle valve 11 is raised. At this time, since the volume of the oil sump 17 increases, the injection pressure of the fuel injected from the injection hole 18 decreases. During fuel injection, the actuator 112 is displaced in the vertical direction at a high cycle, and the above operation is repeated.

When the required amount of injection is performed, the plunger 2
The notch lead 26 of No. 1 faces the oil supply / drain hole 27, the plunger chamber 24 communicates with the oil supply / drain hole 27 via the notch lead 26, and the injection pipe 32 → oil passage 15 → oil passage 16 → oil sump 17
The system becomes low pressure, the needle valve 11 is lowered by the spring 13, and the injection hole 18 is closed. At this time, the drive of the actuator 112 is also stopped by the controller 302.

FIG. 2 shows the relationship among the injection pressure, the needle valve lift, and the crank angle at the time of fuel injection. When the needle valve 11 descends in the closing direction, the injection pressure rises like A, and when the needle valve 11 rises in the opening direction, the injection pressure falls like B. FIG. 3A shows a state of fuel spray when the needle valve 11 is lowered in the closing direction and the injection pressure is increased, and FIG. 3B is shown when the needle valve 11 is raised in the opening direction. , Shows the sprayed state of fuel when the injection pressure drops. Since the size and length of the atomized fuel thus change periodically, the air around the atomized fuel enters the atomized fuel and promotes the mixing of the atomized fuel with the air, resulting in a good mixture. Is obtained.

As described above, the mixing of the spray fuel and the air is promoted to obtain a good air-fuel mixture, so that the excess air ratio in the spray fuel is increased, the good combustion is performed, and the black smoke is generated. Is prevented. Further, the excess air ratio rises, the generation of harmful exhaust substances such as NOx is suppressed, and the emission of harmful exhaust substances decreases.

[0022]

As described above, the fuel injection valve of the present invention displaces the actuator in a high cycle as described above, and at the same time, the movement of the actuator is transmitted to the needle valve via the push rod and the spring receiver, so that the displacement amount of the needle valve is controlled. It is changed in a high cycle to change the injection pressure of the fuel from the injection hole to change the size and length of the atomized fuel and promote the mixing of the atomized fuel with the air around it to create a good mixture. As a result, the excess air ratio in the atomized fuel can be increased, good combustion can be performed, and the generation of black smoke can be prevented. Further, since the excess air ratio is increased, the generation of harmful exhaust substances such as NOx can be suppressed and the emission of harmful exhaust substances can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of a fuel injection valve of the present invention.

FIG. 2 is an explanatory diagram showing a relationship among an injection pressure, a needle valve lift, and a crank angle at the time of fuel injection of the fuel injection valve.

FIG. 3A is an explanatory view showing a fuel spray state when the needle valve descends in the closing direction and the injection pressure rises, and FIG. 3B shows
It is explanatory drawing which shows a fuel spray state when a needle valve rises in the valve opening direction and injection pressure falls.

FIG. 4 is a vertical sectional side view showing a conventional fuel injection device.

FIG. 5 is an explanatory diagram showing a relationship among an injection pressure, a needle valve lift, and a crank angle at the time of fuel injection of the fuel injection device.

FIG. 6 is an explanatory diagram showing a fuel spray state of the fuel injection device.

[Explanation of symbols]

 11 Needle valve 12 Spring bearing 101 Fuel injection valve 111 Push rod 112 Actuator

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[Procedure amendment]

[Submission date] February 22, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

[0011]

The fuel injection valve of the present invention is configured as described above, and while displacing the actuator in a short cycle, the movement of the actuator is transmitted to the needle valve through the push rod and the spring receiver, and The amount of displacement is changed in a short cycle, the injection pressure of the fuel from the injection hole is changed, the size and length of the atomized fuel are changed, and the mixing of the atomized fuel and the air around it is promoted, resulting in good Get a mixture.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

Reference numeral 113 is an actuator chamber wall provided above the spring chamber wall 14, and 112 is the actuator chamber wall 1.
Actuator housed in 13 and displaced in a short cycle, 1
Reference numeral 11 is a push rod that penetrates the spring chamber wall 14 and supports the actuator 112. A spring 114 is interposed between the upper portion of the push rod 111 and the upper portion of the spring chamber wall 14 to push the push rod 111 and the actuator 112. And are urged upward.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

After a minute time has passed, the command from the controller 302 to the driver 301 is turned off, the actuator 112 is displaced upward, and the needle valve 11 is raised. At this time, since the volume of the oil sump 17 increases, the injection pressure of the fuel injected from the injection hole 18 decreases. During fuel injection, the actuator 112 is vertically displaced in a short cycle, and the above operation is repeated.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

[0022]

As described above, the fuel injection valve of the present invention displaces the actuator in a short cycle as described above, and at the same time, the movement of the actuator is transmitted to the needle valve via the push rod and the spring receiver, so that the displacement amount of the needle valve is controlled. It is changed in a short cycle to change the injection pressure of the fuel from the injection hole to change the size and length of the atomized fuel and promote the mixing of the atomized fuel and the air around it to create a good mixture. As a result, the excess air ratio in the atomized fuel can be increased, good combustion can be performed, and the generation of black smoke can be prevented. Further, since the excess air ratio is increased, the generation of harmful exhaust substances such as NOx can be suppressed and the emission of harmful exhaust substances can be reduced.

[Procedure correction 6]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 4

[Correction method] Change

[Correction content]

[Figure 4]

Claims (1)

[Claims] 1. An actuator that displaces at a high cycle is disposed above a needle valve of a fuel injection valve, and the movement of the actuator is transmitted to the needle valve via a push rod and a spring receiver to detect the displacement amount of the needle valve. A fuel injection valve characterized by being changed periodically.