JP2001153001A - Fuel injection device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection device capable of suppressing an increase in the size of a nozzle body to prevent deterioration of the mounting ability of an engine and the assembling workability of a fuel injection device, and preventing reduction in output of the engine or deterioration of the fuel consumption. SOLUTION: A control member 35 constituting a part of a pressure chamber 34, and a spring 36 for giving energizing force in the direction opposite to a lifting direction of a needle valve 26 to the control member 35, are arranged- installed in the pressure chamber 34. A piston 31 and the control member 35 are provided, spaced a specified distance L apart, and the supply fuel is introduced into a space confined by the piston, the control member 35, and a nozzle body 21 to form a pressure chamber 37. A connecting path 42 connecting a part between a throttle part 39a of a fuel discharge passage 39 and a fuel control valve 41 to the pressure chamber 34, is provided. In the connecting path 42, a spool valve 43 is provided, and the spool valve 43 is structured to open or close the connecting path 42.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fuel injection device for injecting fuel into a combustion chamber of an internal combustion engine, particularly a diesel engine.

[0002]

2. Description of the Related Art Conventionally, by controlling a lift amount of a needle valve in accordance with an operation state of an internal combustion engine, characteristics such as a spray angle (spread angle), a penetration force (reach distance), and atomization of fuel spray are obtained. There is a fuel injection device that is variable, and for example, a fuel injection device disclosed in Japanese Patent Application Laid-Open No. 60-308560 is known.

A fuel injection device disclosed in Japanese Patent Application Laid-Open No. 60-308560 has a nozzle body 301 having a fuel injection port 302 for injecting fuel, as shown in FIG.
And a needle valve 303 that is liftably held inside the nozzle body 301 and lifts by the action of the supplied fuel to open the fuel injection port, and a stopper of a rod 305 that abuts on the needle valve 303 and the push rod 304. And a piston 306.
06 is applied with a biasing force in the opposite direction to the lift direction of the needle valve 303 by the spring 307, and moves in the lift direction of the needle valve 303 against the biasing force of the spring 307 by the action of the control oil pressure Pc. It is configured to be able to.

When the control oil pressure Pc is small, the piston 30
6 is stopped at a position where the urging force is applied by the spring 307 in the direction opposite to the lift direction of the needle valve 303 and the spring valve 308 comes into contact with the spring restraint 308. Is limited to the lift amount (pre-lift amount) corresponding to the gap S1.

When the control oil pressure Pc is large, the piston 30
6 moves in the lift direction of the needle valve 303 against the urging force of the spring 307 by the action of the control oil pressure Pc. As the piston 306 moves, the gap between the rod 305 and the piston 306 is smaller than the gap S1 when the control oil pressure Pc is small.
And the lift amount of the needle valve 303 becomes larger than the above-described pre-lift amount (the maximum lift amount: S
1 + S2).

[0006]

When the rod 305 comes into contact with the piston 306 by raising the needle valve 303, the urging force of the spring 307 is applied to the piston 306 (in the direction opposite to the lift direction of the needle valve 303). )
Then, the acting force by the control oil pressure Pc (acting in the lift direction of the needle valve 303) and the acting force by the needle valve 303 (acting in the lift direction of the needle valve 303) act. The acting force of the needle valve 303 is the force by which the needle valve 303 is pushed up by the pressure of the supplied fuel, and is represented by the product of the pressure receiving area of the needle valve 303 and the pressure of the supplied fuel. The pressure receiving area of the needle valve 303 is
And can be easily calculated from the diameter of the needle valve 303.

In order to limit the lift amount of the needle valve 303 to the pre-lift amount, the urging force of the spring 307 must be set to be larger than the sum of the acting force of the control oil pressure Pc and the acting force of the needle valve 303. Therefore, the biasing force required for the spring 307 was calculated from these relationships. In recent years, the pressure of the supplied fuel has been increased to more than 150 MPa in order to improve the exhaust gas purification performance by atomizing the fuel. When the pressure of the supplied fuel exceeds 150 MPa, the spring 307 is required. The urging force is 18
It is about 40N. Here, the control oil pressure Pc for limiting the lift amount of the needle valve 303 to the pre-lift amount is 0 M
Pa and the diameter of the needle valve 303 are 4 mm.

As described above, when the pressure of the supplied fuel is increased, the urging force required for the spring 307 becomes extremely large, and a considerably large wire diameter is required to set the urging force. Spring must be used. However, if a spring having a considerably large wire diameter as described above is used, the outer shape of the nozzle body 301 also becomes large,
The mountability of the nozzle body 301 on the engine is deteriorated. Further, it is not easy to assemble the piston 306 (stopper) by applying the extremely large urging force as described above, and the workability of assembling the fuel injection device is deteriorated.

Next, the control hydraulic pressure Pc required to lift the lift amount of the needle valve 303 larger than the pre-lift amount was calculated. The hydraulic pressure required to overcome the urging force of the spring 307 is the urging force / pressure receiving area.
73MPa when the biasing force of the above is 1840N described above.
About. Here, the diameter of the large diameter portion of the piston 306 is 7 mm, and the diameter of the small diameter portion is 4 mm. Therefore, the control oil pressure Pc required to lift the lift amount of the needle valve 303 larger than the pre-lift amount is from the above-mentioned 73 MPa to the pressure of the supplied fuel (the minimum fuel injection pressure is 2
(About 0 MPa), which is about 50 MPa, and a considerably high value is required as the control oil pressure. In order to generate the above-described control oil pressure Pc, a hydraulic pressure source such as a high-pressure hydraulic pump is required. However, such a high-pressure hydraulic pump generally has a large power loss, and requires an engine to drive the hydraulic pump. This leads to a decrease in output and a deterioration in fuel efficiency.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is possible to suppress an increase in the size of a nozzle body to prevent deterioration in mountability to an engine and workability in assembling a fuel injection device, and to reduce engine output. It is an object of the present invention to provide a fuel injection device for an internal combustion engine that can prevent a decrease in fuel consumption and a decrease in fuel efficiency.

[0011]

SUMMARY OF THE INVENTION A fuel injection device for an internal combustion engine according to the present invention has a nozzle body having a fuel injection port for injecting fuel, and is held in the nozzle body so as to be liftable. A valve member that is lifted by an action to open the fuel injection port, and the valve member is provided at a distance corresponding to a predetermined lift amount, and a lift control member that can contact the valve member and a lift control member are part of the valve member. A lift control chamber into which supply fuel is introduced, an urging force applying member provided in the lift control chamber, and applying an urging force to the lift control member in a direction opposite to a lift direction of the valve member; The pressure in the lift control chamber is made lower than the pressure of the supplied fuel acting on the valve member by discharging the fuel in the chamber, and the discharge of the fuel in the lift control chamber is prohibited by discharging the fuel in the lift control chamber. It is characterized by comprising a lift control chamber pressure adjusting means for an equivalent state and pressure feed fuel acting pressure on the valve member.

The fuel injection device for an internal combustion engine according to the present invention includes the above-described lift control member, lift control chamber, urging force applying member, and lift control room pressure adjusting means. When the pressure adjusting means prohibits the discharge of the fuel in the lift control chamber to make the pressure in the lift control chamber equal to the pressure of the supplied fuel acting on the valve member, the valve member lifts by the action of the pressure of the supplied fuel. Then, since the movement of the valve member in the lift direction is restricted by the pressure in the lift control chamber of the lift control member, the valve member comes into contact with the lift control member and the lift is limited. Therefore, the lift amount of the valve member is limited to the lift amount corresponding to the distance between the valve member and the lift control member. On the other hand, when the pressure in the lift control chamber is made lower than the pressure of the supplied fuel acting on the valve member by discharging the fuel in the lift control chamber by the lift control chamber pressure adjusting means, the valve member acts on the pressure of the supplied fuel. When the valve member lifts, the valve member comes into contact with the lift control member, but the pressure in the lift control chamber is reduced, and the lift control member is also movable in the lift direction of the valve member. The lift is further increased than the lift amount corresponding to the distance between the valve member and the lift control member.

Therefore, the control of the lift amount of the valve member is
This is performed mainly based on the magnitude of the pressure in the lift control chamber, and the urging force of the urging force applying member may be such that the lift control member can return to the initial position. As a result, the urging force of the urging force applying member can be set smaller than that of the above-described conventional one, suppressing an increase in the size of the nozzle body, mounting the engine on the engine and assembling work of the fuel injection device. Deterioration can be prevented. In addition, since the supplied fuel is guided to the lift control chamber and the pressure of the supplied fuel is used as the pressure of the lift control chamber, it is possible to control the lift amount of the valve member without providing a new hydraulic pressure source. In addition, the power required to generate the hydraulic pressure is smaller than that of the above-described conventional one. As a result, it is possible to prevent a decrease in engine output and a decrease in fuel efficiency.

Further, the fuel injection device is further defined by a valve member and a lift control member, and communicates with the fuel control chamber to which the supplied fuel is guided, and discharges the fuel in the fuel control chamber. A fuel discharge passage, and a fuel control valve provided in the middle of the fuel discharge passage for opening and closing the fuel discharge passage, wherein the lift control chamber pressure adjusting means is closer to the fuel control chamber than the fuel control valve of the fuel discharge passage. It is preferable to have a communication passage for communicating the portion with the lift control chamber, and a lift control valve provided in the middle of the communication passage for opening and closing the communication passage.
With such a configuration, when the fuel discharge passage is closed by the fuel control valve, the pressure in the fuel control chamber becomes equal to the pressure of the supplied fuel, and the valve member does not lift. When the fuel discharge passage is opened by the fuel control valve, the fuel in the fuel control chamber is discharged, the pressure in the fuel control chamber becomes lower than the pressure of the supplied fuel, and the valve member lifts. When the fuel discharge passage is opened by the fuel control valve and the communication passage is closed by the lift control valve, the pressure in the lift control chamber becomes equal to the pressure of the supplied fuel acting on the valve member. The member abuts the lift control member to limit its lift. On the other hand, when the fuel discharge passage is opened by the fuel control valve and the communication passage is opened by the lift control valve, the pressure in the lift control chamber becomes lower than the pressure of the supplied fuel acting on the valve member,
As described above, the valve member is further lifted even after contacting the lift control member. Therefore, the fuel is injected from the fuel injection port by having a communication passage that communicates a portion of the fuel discharge passage closer to the fuel control chamber than the fuel control valve with the lift control chamber and a lift control valve that opens and closes the communication passage. With the opening and closing control of the fuel discharge passage by the fuel control valve for
It is possible to control discharge or prohibition of discharge of fuel in the lift control chamber, and control pressure in the lift control chamber in synchronization with fuel injection. Further, a structure capable of controlling the pressure in the lift control chamber can be realized simply and at low cost with a very simple configuration of the communication passage and the lift control valve.

It is preferable that the lift control valve is constituted by a spool valve that is switched between a state in which the communication path is opened and a state in which the communication path is closed by control hydraulic pressure sent from a hydraulic pressure source. In the case of such a configuration, the control oil pressure only needs to be a relatively low oil pressure capable of operating the spool valve, and power loss due to driving of the oil pressure source is reduced. As a result, even when a hydraulic pressure source for generating a control hydraulic pressure is provided, a decrease in engine output and a decrease in fuel efficiency can be suppressed as much as possible.

In the lift control member, a fuel passage for communicating the fuel control chamber with the lift control chamber is provided at a position closed by the valve member when the valve member contacts the lift control member. Is preferred. As described above, by providing the fuel passage in the lift control member, the pressure in the fuel control chamber and the pressure in the lift control chamber can be reliably made equal. Also, when the valve member lifts and comes into contact with the lift control member, the fuel passage is closed by the valve member, so that fuel in the lift control chamber leaks from the fuel passage to the fuel control chamber, or Fuel does not leak into the lift control chamber, and the pressure in the lift control chamber can be appropriately maintained.

Further, it is preferable that the lift control chamber pressure adjusting means has a lift control valve for selecting a state in which fuel is supplied to the lift control chamber and a state in which fuel in the lift control chamber is discharged. In the case of such a configuration, when the state in which the fuel supply is guided to the lift control chamber by the lift control valve is selected, the pressure in the lift control chamber becomes equal to the pressure of the supply fuel acting on the valve member, as described above. The valve member contacts the lift control member to limit the lift. On the other hand, when the state in which the fuel in the lift control chamber is discharged by the lift control valve is selected, the pressure in the lift control chamber becomes lower than the pressure of the supplied fuel acting on the valve member. After contact with the member, it is further lifted. As a result, the pressure in the lift control chamber can be controlled by the lift control valve, and the structure capable of controlling the pressure in the lift control chamber is simple and low-cost with a very simple configuration of the lift control valve. It becomes feasible.

The lift control valve is constituted by a spool valve that is switched to a state in which fuel is supplied to the lift control chamber or a state in which fuel in the lift control chamber is discharged by control hydraulic pressure sent from a hydraulic pressure source. Is preferred. The control oil pressure only needs to be a relatively low oil pressure capable of operating the spool valve, and power loss due to driving of the oil pressure source is reduced. As a result, even when a hydraulic pressure source for generating a control hydraulic pressure is provided, a decrease in engine output and a decrease in fuel efficiency can be suppressed as much as possible.

[0019]

Embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description.

(First Embodiment) First, a fuel injection device for an internal combustion engine according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram showing the configuration of the fuel injection device. In the first embodiment, the fuel injection device for an internal combustion engine according to the present invention is applied to a pressure accumulating fuel injection device for a diesel engine.

In the fuel injection device 1, the fuel tank 2
The fuel sucked up by the feed pump 3 and pressurized to a predetermined suction pressure is sent to the high-pressure fuel pump 5 through the fuel pipe 4. The high-pressure fuel pump 5 is a so-called plunger-type supply fuel supply pump driven by, for example, an engine. The high-pressure fuel pump 5 pressurizes the fuel to a high pressure determined based on an operation state and the like, and pressurizes the pressurized fuel to a fuel pipe 7. Through the common rail 8. The fuel stored in the common rail 8 while being pressurized to a predetermined pressure is
The fuel is supplied as fuel from the common rail 8 to a plurality of fuel injection valves 10 through a fuel supply pipe 9. In FIG. 1, a four-cylinder diesel engine E is shown as an internal combustion engine, and four cylinders (not shown) of the engine E have fuel injection valves for injecting fuel into combustion chambers formed therein. 10 are provided.

The ECU 11 includes various sensors, that is, a crank angle sensor 12 for detecting a crank angle,
Accelerator opening sensor 1 for detecting accelerator opening
3. Signals from various sensors for detecting the operating state of the engine, such as a water temperature sensor for detecting the temperature of the cooling water and a pressure sensor in the intake pipe for detecting the pressure in the intake pipe, are input. The common rail 8 is provided in the ECU 11.
A detection signal of the fuel pressure in the common rail 8 detected by a pressure sensor (not shown) provided in the controller is sent.

The ECU 11 performs the following based on these signals.
The fuel injection timing and the injection amount of the fuel injection valve 10 are controlled so that the engine output becomes the optimum output in accordance with the operation state, and the fuel corresponds to the optimum injection timing with the optimum fuel injection amount. Fuel injection valve 1
The fuel control valve 41 provided at 0 is controlled. Fuel injection valve 10
The injection pressure of the fuel injected from the common rail 8 is substantially equal to the pressure of the fuel stored in the common rail 8. Since the fuel injection amount is determined by the injection period and the injection pressure, the fuel injection pressure is controlled by controlling the flow control valve 6 to control the supply amount of the high-pressure fuel to the common rail 8. When the fuel in the common rail 8 is consumed by the injection of the fuel from the fuel injection valve 10 or when the fuel injection amount is changed, the ECU 11 sets the fuel pressure in the common rail 8 to a predetermined fuel pressure. The flow control valve 6 is controlled to control the amount of fuel discharged from the high-pressure fuel pump 5 to the common rail 8. The common rail fuel injection system itself is conventionally known, and further detailed description will be omitted.

The fuel injection valve 10 has a nozzle body 21 as a valve body, as shown in FIG. At the tip of the nozzle body 21, a fuel injection port 2 for injecting fuel is provided.
2 and a substantially conical valve seat 23 communicating with the fuel injection port 22 at an inner side thereof. Nozzle body 21
Is provided with a valve hole 24 and a guide hole 25 at the center thereof. The valve hole 24 has a smaller diameter than the guide hole 25 as shown in FIG. A needle valve 26 is slidably and precisely fitted inside the valve hole 24. The needle valve 26 has a conical tip that can contact the valve seat 23. The needle valve 26 is raised and lowered (lifted) by receiving the pressure of the supplied fuel described later, whereby the distance between the valve seat 23 and the conical tip of the needle valve 26 is controlled to intermittently inject the fuel. The fuel is injected into the combustion chamber through the port 22.

The needle valve 26 has a conical pressure receiving surface 2.
6a is formed, and a fuel reservoir 27 is formed between the conical pressure receiving surface 26a and the nozzle body 21 (valve hole 24). One end of the nozzle body 21 has a fuel reservoir 2
7, a fuel passage 28 having the other end connected to the fuel supply pipe 9 is formed. Therefore, the conical pressure receiving surface 26 a of the needle valve 26 is provided with the fuel supply pipe 9 and the fuel passage 2.
It is configured such that the pressure of the supplied fuel guided to the fuel reservoir 27 via the pressure 8 acts.

The fuel injection port 22 has a first fuel injection port 22a provided on the tip end side of the nozzle body 21 and a second fuel injection port 22b provided behind the first fuel injection port 22a.
According to the lift amount of the needle valve 26 (cone-shaped tip), when the lift amount is equal to or less than a predetermined lift amount (L), fuel is injected and supplied from the second fuel injection port 22b, and the lift amount is reduced. If it is larger than the predetermined lift amount (L), the first
It is configured to inject and supply fuel from the fuel injection port 22a and the second fuel injection port 22b.

A piston 31 is slidably and precisely fitted into the guide hole 25. Piston 31 and needle valve 2
As shown in FIG. 1, there is a rod 3 for defining the distance between the piston 31 and the needle valve 26.
2 and a spring 33 that abuts against the piston 31 and the needle valve 26 and applies an urging force to the needle valve 26 in a direction opposite to the lift direction of the needle valve 26 (downward in FIG. 1). Has been established. Here, needle valve 2
6, the piston 31 and the rod 32 constitute a valve member in each claim. In the present embodiment,
Although the needle valve 26, the piston 31 and the rod 32 are formed separately from each other, for example, the needle valve 26 and the rod 32 may be integrally formed, or the needle valve 26, the piston 31 and the rod 32 And may be integrally configured.

As shown in FIG. 1, a pressure chamber 34 having a larger diameter than the guide hole 25 is formed in the nozzle body 21 so as to be continuous with the guide hole 25. It constitutes a lift control room. This pressure chamber 34
Has a control member 3 capable of controlling the state of communication with the guide hole 25.
The control member 35 constitutes a lift control member in each claim. The control member 35 is
The needle valve 26 can move in the pressure chamber 34 in the lift direction and in the direction opposite to the lift direction. In the control member 35, the surface 35a on the piston 31 side has a substantially conical shape, and the substantially conical surface 35a is
4 and the guide hole 25, the communication between the pressure chamber 34 and the guide hole 25 is interrupted by contact with the step 21a.
, The pressure chamber 34 and the guide hole 25 are in communication with each other. A spring 36 is provided in the pressure chamber 34 to apply a biasing force to the control member 35 in a direction opposite to the lift direction of the needle valve 26 (downward in FIG. 1). 36 constitutes an urging force urging member in each claim.

As shown in FIG. 1, the piston 31 and the control member 35 are in a position where the piston 31 is at the position most opposite to the lift direction of the needle valve 26 (downward in FIG. 1). (Surface 35a) is the pressure chamber 34 and the guide hole 2
5 are provided at a predetermined distance L when in a position (initial position) in contact with the stepped portion 21a formed by the piston 31, the control member 35, and the nozzle body 21 (the guide hole). A pressure chamber 37 defined by 25) is formed between the piston 31 and the control member 35. The pressure chamber 37 is branched from the fuel passage 28 and has a throttle portion 38a.
Is connected to the fuel passage 38,
The supply fuel is guided from the fuel passage 28 to the pressure chamber 37 via the fuel passage 28. Here, the pressure chamber 37 constitutes a fuel control chamber in each claim.

From a portion of the fuel passage 38 closer to the pressure chamber 37 than the throttle portion 38a, a fuel discharge passage 39 for discharging fuel to the outside of the fuel injection valve 10 via a throttle portion 39a is provided in a branched manner. I have. Throttle section 39a of fuel discharge passage 39
A fuel control valve 41 is provided in a portion further downstream than the fuel control valve 41. The fuel control valve 41 is an electromagnetic valve,
It operates based on the control signal sent from the
It is configured to open and close the fuel discharge passage 39 downstream of 9a.

A communication passage 42 is formed in the nozzle body 21 to communicate a portion of the fuel discharge passage 39 between the throttle portion 39a and the fuel control valve 41 and the pressure chamber 34 via the throttle portion 42a. ing. A spool valve 43 as a lift control valve is provided at a portion between the throttle portion 42a of the communication passage 42 and the fuel control valve 41, and the spool valve 43 is configured to open and close the communication passage 42. I have. The spool valve 43 is supplied to the hydraulic control unit 45 from a hydraulic pump 44 as a hydraulic pressure source.
When the control hydraulic pressure is lower than the operating pressure defined by the urging force of the spring 43a, the communication passage 42 is closed, and the control described above is performed. When the hydraulic pressure is higher than the operating pressure defined by the urging force of the spring 43a, the communication passage 42 is opened.

The pressure chamber 34 includes a pressure chamber 34 and a pressure chamber 37.
When there is a pressure difference between the control member 35 and the surface 35
Since the fuel in the pressure chamber 37 is guided by the separation of the a from the step portion 21a, the pressure of the supplied fuel guided into the pressure chamber 34 acts on the control member 35.
Therefore, the surface 35b of the control member 35 facing the pressure chamber 34
Constitutes a pressure receiving surface that receives pressure from the supplied fuel introduced into the pressure chamber 34, and constitutes a part of the pressure chamber 34. The area of the surface 35 b of the control member 35 facing the pressure chamber 34 is larger than the pressure receiving area where the needle valve 26 receives the pressure of the supplied fuel in the fuel reservoir 27.

The hydraulic control unit 45 operates based on a control signal sent from the ECU 11, adjusts the pressure of the pressure oil sent from the hydraulic pump 44, and controls a control pressure for controlling the operation of the spool valve 43. Is configured to generate The ECU 11 determines whether or not the engine E is in a predetermined operating state (for example, low rotation and low load) based on output signals from the crank angle sensor 12 and the accelerator opening sensor 13, and determines whether the engine E is in the predetermined operating state. The control oil pressure is applied to the oil pressure control unit 45 by the spring 43.
a control signal is output so as to be lower than the operating pressure specified by the urging force of the a.
The control signal is output so as to be higher than the operating pressure defined by the biasing force of 3a.

Next, the operation of the fuel injection valve 10 configured as described above will be described with reference to FIG.
FIG. 2 is a diagram showing the relationship between the open / closed state of the spool valve 43, the open / closed state of the fuel control valve 41, and the lift amount of the needle valve.

When the hydraulic control unit 45 sets the control oil pressure higher than the operating pressure specified by the urging force of the spring 43a based on the control signal sent from the ECU 11, the spool valve 43 opens the communication passage 42. (Fig. 2
Region indicated by middle arrow A). When the spool valve 43 opens the communication passage 42 in this manner, the fuel control valve 4
When the fuel supply passage 1 opens the fuel discharge passage 39 based on the control signal sent from the ECU 11, the supply fuel in the pressure chamber 34 is discharged through the fuel discharge passage 39 and the fuel control valve 41. Become.

When the fuel control valve 41 closes the fuel discharge passage 39, the fuel on the common rail 8 is guided to the fuel reservoir 27 and the pressure chamber 37 through the fuel supply pipe 9, and the fuel reservoir 27 The pressure of the supplied fuel introduced into the pressure chamber 37 is equal to the fuel pressure in the common rail 8. At this time, the pressure in the pressure chamber 37 is
When the pressure is higher than the pressure in the pressure chamber 37, the pressure of the fuel supplied in the pressure chamber 37 causes the surface 3 of the control
The acting force acts in a direction in which the pressure chamber 5a moves away from the step 21a, and the pressure chamber 34 and the pressure chamber 37 are in communication. Therefore, the pressure in the pressure chamber 37 is maintained at the same pressure as the pressure in the pressure chamber 34. Further, since the pressure of the fuel supplied in the pressure chamber 37 acts on the needle valve 26 via the piston 31 and the rod 32 in a direction opposite to the lift direction of the needle valve 26, the needle valve 26 has a valve seat. The state of sitting on the portion 23 is maintained, and the fuel is not injected and supplied from the fuel injection port 22. Also, the piston 31
A gap of a distance L is formed between the control member 35 and the control member 35 as shown in FIG.

As described above, when the fuel control valve 41 opens the fuel discharge passage 39 and the supply fuel in the pressure chamber 37 is discharged through the throttle portion 39a and the fuel control valve 41, the pressure chamber 37 The pressure of the supplied fuel in the fuel reservoir 27 becomes lower than the pressure of the supplied fuel in the fuel reservoir 27. Thus, the pressure chamber 3
When the pressure balance between the fuel valve 7 and the fuel reservoir 27 is lost, the needle valve 26
The needle valve 26 starts lifting, and the needle valve 26 starts to separate from the valve seat 23.

When the needle valve 26 is lifted to an amount corresponding to the distance L of the gap formed between the piston 31 and the control member 35, the piston 31 comes into contact with the control member 35. At this time, the supply fuel in the pressure chamber 34 is discharged through the communication passage 42, the fuel control valve 41, and the fuel discharge passage 39 because the spool valve 43 has opened the communication passage 42. Therefore, the pressure in the pressure chamber 34 is also lower than the pressure of the supplied fuel in the fuel reservoir 27. Therefore, the needle valve 26
Means that the piston 31 and the control member 35 continue to lift even after the piston 31 and the control member 35 come into contact with each other.
5 will be lifted more than the lift amount corresponding to the distance L of the gap formed between them. As described above, when the lift amount of the needle valve 26 is larger than the lift amount corresponding to the distance L of the gap formed between the piston 31 and the control member 35, the fuel injection valve 10
The fuel is injected from the second fuel injection port 22a and the second fuel injection port 22b.

On the other hand, when the hydraulic control unit 45 lowers the control oil pressure below the operating pressure defined by the urging force of the spring 43a based on the control signal sent from the ECU 11, the spool valve 43 Is closed (region indicated by arrow B in FIG. 2). When the fuel control valve 41 opens the fuel discharge passage 39 based on the control signal sent from the ECU 11 in the state where the spool valve 43 closes the communication passage 42, the supply in the pressure chamber 37 is stopped. The fuel is discharged through the throttle portion 39a and the fuel control valve 41.

When the fuel control valve 41 opens the fuel discharge passage 39 and the fuel in the pressure chamber 37 is discharged through the throttle portion 39a and the fuel control valve 41, the pressure of the supplied fuel in the pressure chamber 37 is reduced. Becomes lower than the pressure of the supplied fuel in the fuel reservoir 27, and as described above, the acting force in the lift direction acts on the needle valve 26 by the pressure of the supplied fuel in the fuel reservoir 27, and the needle valve 26 is actuated. The lift starts, and the needle valve 26 starts to separate from the valve seat 23.

When the needle valve 26 is lifted to an amount corresponding to the distance L of the gap formed between the piston 31 and the control member 35, the piston 31 and the control member 35 come into contact. At this time, the supply fuel in the pressure chamber 34 is in a state where the spool valve 43 closes the communication passage 42 and its discharge is prohibited. It is maintained at a pressure equivalent to the pressure of the fuel supplied inside. Further, since the area of the surface 35b of the control member 35 is larger than the pressure receiving area where the needle valve 26 receives the pressure of the supplied fuel in the fuel reservoir 27, it acts on the surface 35b of the control member 35 to push down the piston 31. The force to be applied is larger than the force acting on the needle valve 26 in the lift direction. When the piston 31 and the control member 35 abut, the further lift of the needle valve 26 is restricted. Therefore, the lift of the needle valve 26 is limited when the piston 31 and the control member 35 come into contact with each other, and the lift amount of the needle valve 26 is limited by the gap formed between the piston 31 and the control member 35. Is limited to a lift amount corresponding to the distance L of the so-called pre-lift amount. Thus, in a state where the lift amount of the needle valve 26 is limited to the pre-lift amount (L),
The fuel injection valve 10 injects and supplies fuel from the second fuel injection port 22b.

As described above, according to the fuel injection device 1 of the first embodiment, when the lift amount of the needle valve 26 is limited to the pre-lift amount (L), the fuel injection valve 10 operates in the second fuel injection mode. Since the fuel is injected and supplied from the port 22b, the minimum fuel passage area in the fuel injection valve 10 is reduced, and the injection rate can be suppressed. By suppressing the injection rate in this manner, the premixed combustion ratio can be reduced, and a sudden increase in pressure at the beginning of combustion can be suppressed, thereby reducing combustion noise. Further, since the combustion temperature can be lowered, the generation of NOx can be suppressed. On the other hand, when the lift amount of the needle valve 26 is larger than the pre-lift amount (L), the fuel injection valve 10 is connected to the first fuel injection port 22a.
In addition, since the fuel is injected and supplied from the second fuel injection port 22b, the injection period can be shortened, and the combustion after the short combustion period and less burning can be performed. As described above, since the thermal efficiency is improved in the combustion in which the afterburning is short and the afterburning is small, the output of the engine E can be improved.

Further, the number of fuel injection ports 22 (first fuel injection ports 22a and second fuel injection ports 22b) for injecting fuel is switched according to the lift amount of the needle valve 26. The number of the fuel injection ports 22 (the first fuel injection ports 22a and the second fuel injection ports 22b) that can obtain good engine performance can be appropriately selected according to the state.

As described above, the fuel injection valve 10 includes the control member 35, the pressure chamber 34, the spring 36, the pressure chamber 37, the fuel control valve 41, and the spool valve 43. When the fuel discharge passage 39 is closed by the valve 41, the pressure in the pressure chamber 34 becomes equal to the pressure of the supplied fuel in the fuel reservoir 27, and the needle valve 26 does not lift. When the fuel discharge passage 39 is opened by the fuel control valve 41, the fuel in the pressure chamber 37 is discharged and the pressure in the pressure chamber 37 becomes lower than the pressure of the supplied fuel in the fuel reservoir 27, and the needle valve 26 is lifted. When the fuel discharge passage 39 is opened by the fuel control valve 41 and the communication passage 42 is closed by the spool valve 43, the pressure in the pressure chamber 34 is
The pressure becomes equal to the pressure of the supplied fuel in the inside, that is, the pressure of the supplied fuel acting on the needle valve 26 in the lift direction of the needle valve 26, the piston 31 abuts on the control member 35, and the lift of the needle valve 26 becomes the pre-lift amount ( L). On the other hand, when the fuel discharge passage 39 is opened by the fuel control valve 41 and the communication passage 42 is opened by the spool valve 43, the pressure in the pressure chamber 34 becomes the pressure of the supply fuel in the fuel reservoir 27, that is, Needle valve 26
The needle valve 26 is further lifted even after the pressure of the supplied fuel acting in the lift direction of the needle valve 26 becomes lower and the piston 31 comes into contact with the control member 35.

Therefore, the lift of the needle valve 26 is controlled mainly based on the magnitude of the pressure of the supplied fuel introduced into the pressure chamber 34, and the biasing force of the spring 36 controls the control member 35. It is sufficient that the surface 35a can be returned to a position (initial position) where the surface 35a contacts the step portion 21a.
As a result, the biasing force of the spring 36 can be set smaller than that of the conventional one, and the size of the nozzle body 21 is suppressed, and the mounting property to the engine E and the workability of assembling the fuel injection valve 10 are deteriorated. Can be prevented. Also, the pressure chamber 3
Since the supply fuel is guided to the pressure chamber 4 and the pressure of the supply fuel is used as the pressure of the pressure chamber 34, it is possible to control the lift amount of the needle valve 26 without providing a new hydraulic pressure source. The power required to generate it is smaller than that of the conventional one. As a result, it is possible to prevent a decrease in the output of the engine E and a deterioration in fuel efficiency.

The communication passage 4 is controlled by the spool valve 43.
When the fuel cell 2 is opened, the pressure chamber 34 is opened and closed by controlling the opening and closing of the fuel discharge passage 39 by the fuel control valve 41.
It is possible to control the discharge or prohibition of discharge of the fuel in the chamber, and it is possible to control the pressure in the pressure chamber 34 in synchronization with the fuel injection. Further, a structure capable of controlling the pressure in the pressure chamber 34 can be realized simply and at low cost with an extremely simple configuration of the communication passage 42 and the spool valve 43.

The communication passage 4 is controlled by the spool valve 43.
2 is switched between the open state and the closed state, the control oil pressure for operating the spool valve 43 may be a relatively low oil pressure, and the power loss due to the driving of the hydraulic pump 44 for generating the control oil pressure Becomes smaller. As a result, even when the hydraulic pump 44 that generates the control hydraulic pressure is provided, it is possible to minimize a decrease in the output of the engine E and a deterioration in fuel efficiency.

Next, the control member 3 included in the first embodiment
Modification 5 will be described with reference to FIGS. FIG.
FIG. 4 is a sectional view of a main part showing a modification of the control member 35, and FIG. 4 is a plan view showing a modification of the control member 35. The shape of the control member 35 described above is different from that of the control member 51 in the modified example.

The control member 51 is formed in a disk shape as shown in FIGS. 3 and 4, and a fuel passage 52 is formed at a substantially central position. The fuel passage 52 is provided in the pressure chamber 3
The pressure chamber 37 communicates with the pressure chamber 37, and the supply fuel guided to the pressure chamber 37 can be guided to the pressure chamber 34. The position where the fuel passage 52 is formed is a position where the fuel passage 52 is closed by the piston 31 when the needle valve 26 is lifted and the piston 31 comes into contact with the control member 51.

When the needle valve 26 is not lifted, the pressure chamber 34 and the pressure chamber 37 communicate with each other through the fuel passage 52 as described above. It will be maintained at a pressure equivalent to the pressure of the supply fuel in 37.

The fuel control valve 41 is connected to the fuel discharge passage 39.
Is opened, the fuel in the pressure chamber 37 is discharged, the pressure of the supplied fuel in the pressure chamber 37 becomes lower than the pressure of the supplied fuel in the fuel reservoir 27, the needle valve 26 starts lifting, and the piston 31 When the control member 51 comes into contact with the control member 51, the fuel passage 52 is closed by the piston 31. Therefore, when the spool valve 43 closes the communication passage 42 and the discharge of the fuel in the pressure chamber 34 is prohibited,
When the communication between the pressure chamber 34 and the pressure chamber 37 is interrupted, the pressure chamber 34 is in a substantially sealed state, and the lift of the needle valve 26 beyond the position where the piston 31 and the control member 51 abut is restricted. Will be. Therefore, the needle valve 2
When the piston 31 and the control member 35 contact each other, the lift of the needle valve 26 is limited, and the lift amount of the needle valve 26 is limited to the pre-lift amount (L).

As described above, the modifications shown in FIGS. 3 and 4 have the same functions and effects as those of the first embodiment, and the control member 51 has the fuel passage 5.
By providing 2, the pressure in the pressure chamber 34 and the pressure in the pressure chamber 37 can be reliably made equal. When the needle valve 26 lifts and the piston 31 and the control member 51 come into contact with each other, the fuel passage 52 is closed by the piston 31, so that the fuel supplied in the pressure chamber 34 is supplied to the fuel passage 5.
2 does not leak into the pressure chamber 37, or fuel supplied in the pressure chamber 37 does not leak into the pressure chamber 34,
The internal pressure can be maintained appropriately.

As a further modification, instead of using the spool valve 43, an electromagnetic control valve that opens and closes the communication passage 42 according to a control signal sent from the ECU 11 may be used. In this case, since the spool valve 43, the hydraulic pump 44 for controlling the operation of the spool valve 43, and the hydraulic control unit 45 are not required, the configuration of the fuel injection device 1 can be extremely simplified.

(Second Embodiment) Next, a fuel injection device for an internal combustion engine according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a schematic diagram showing the configuration of the fuel injection device. In the first embodiment, the fuel injection device for an internal combustion engine according to the present invention is applied to a fuel injection device for a diesel engine using a distribution type fuel injection pump.

As shown in FIG. 5, the fuel injection device 101 includes a distribution type fuel injection pump 102 for pumping fuel,
A fuel injection valve 110 for injecting fuel into a combustion chamber formed for each cylinder of a multi-cylinder diesel engine, and a fuel for supplying from a distribution type fuel injection pump 102 to a fuel injection valve 110 provided for each cylinder And a supply pipe 103. The distribution type fuel injection pump 102 itself
This is a conventionally known device, and a detailed description thereof will be omitted.

The fuel injection valve 110 has a nozzle body 121 as a valve body as shown in FIG. At the tip of the nozzle body 121, a fuel injection port 22 for injecting fuel, and a substantially conical valve seat 23 communicating with the fuel injection port 22 inside the fuel injection port 22 are formed. The nozzle body 121 is provided with a valve hole 124 and a guide hole 125 at the center thereof. The valve hole 124 has a smaller diameter than a pressure chamber 134 described later. The needle valve 26 is slidably and precisely fitted inside the valve hole 124. The needle valve 26 has a conical tip that can contact the valve seat 23. The needle valve 26 is raised and lowered (lifted) by receiving the pressure of the supplied fuel described later, whereby the distance between the valve seat 23 and the conical tip of the needle valve 26 is controlled to intermittently inject the fuel. The fuel is injected into the combustion chamber through the port 22.

The needle valve 26 has a conical pressure receiving surface 2.
6a is formed between the conical pressure receiving surface 26a and the nozzle body 121 (valve hole 124).
Is formed. A fuel passage 28 is formed in the nozzle body 121, one end of which opens into the fuel reservoir 27 and the other end of which is connected to the fuel supply pipe 103. Therefore, the pressure of the supplied fuel guided to the fuel reservoir 27 via the fuel supply pipe 9 and the fuel passage 28 acts on the conical pressure receiving surface 26a of the needle valve 26.

The fuel injection port 22 has a first fuel injection port 22a provided on the tip side of the nozzle body 121 and a second fuel injection port 22 provided on the rear side of the first fuel injection port 22a.
b, according to the lift amount of the needle valve 26 (conical tip), when the lift amount is equal to or less than a predetermined lift amount (L), the fuel is injected and supplied from the second fuel injection port 22b,
When the lift amount is larger than a predetermined lift amount (L), the fuel is injected and supplied from the first fuel injection port 22a and the second fuel injection port 22b.

A piston 131 is slidably and precisely fitted into the guide hole 125. As shown in FIG. 5, a rod 132 for defining the distance between the piston 131 and the needle valve 26 and a piston 132 and a needle valve 26 are provided between the piston 131 and the needle valve 26, respectively. In contact with the needle valve 26
And a spring 133 for applying a biasing force in a direction (downward in FIG. 1) opposite to the lift direction of the spring 133. Here, the needle valve 26, the piston 131, and the rod 132 constitute a valve member in each claim. In the present embodiment, the needle valve 26, the piston 131, and the rod 132 are formed separately from each other. However, for example, the needle valve 26 and the rod 132 may be formed integrally, The valve 26, the piston 131, and the rod 132 may be integrally formed.

As shown in FIG. 5, a pressure chamber 134 having a larger diameter than the valve hole 124 is formed in the nozzle body 121 so as to be continuous with the guide hole 125. It constitutes a lift control room. A control member 135 is provided in the pressure chamber 134 so as to cut off communication between the guide hole 125 and the pressure chamber 134, and the control member 135 constitutes a lift control member in each claim. Therefore, the control member 1 is
In a state where 35 is provided, the pressure chamber 134 is hydraulically isolated from the guide hole 125. Further, the control member 135 is movable in the pressure chamber 134 in the lift direction of the needle valve 26 and in a direction opposite to the lift direction. In the pressure chamber 134, a spring 36 for applying a biasing force to the control member 135 in a direction opposite to the lift direction of the needle valve 26 (downward in FIG. 5) is provided.
The spring 36 constitutes an urging force urging member in each claim.

As shown in FIG. 5, the piston 131 and the control member 135 are located at the position where the piston 131 is most opposite to the lift direction of the needle valve 26 (downward in FIG. 5). Is located at a position (initial position) most opposite to the lift direction of the needle valve 26 (downward in FIG. 5), and is provided at a predetermined distance L. A piston chamber 137 defined by 135 and the nozzle body 121 (guide hole 25) is formed between the piston 131 and the control member 135.

The pressure chamber 1 is provided in the nozzle body 121.
A fuel passage 161 for guiding the fuel in the fuel passage 28 to the fuel passage 34
Is connected. In the middle part of the fuel passage 161,
A spool valve 143 as a lift control valve is provided.
, And a state in which the fuel in the pressure chamber 134 is discharged through the fuel discharge passage 162. The spool valve 143 is operated by the control oil pressure of the hydraulic oil adjusted by the hydraulic control unit 45 when the hydraulic oil is sent from the hydraulic pump 44 as a hydraulic source to the hydraulic control unit 45. When the operating pressure is lower than the operating pressure defined by the biasing force of the spring 143a, the fuel in the pressure chamber 134 is discharged through the fuel discharge passage 162, and the above-described control oil pressure is adjusted to the operating pressure defined by the biasing force of the spring 143a. When the pressure is higher, the supply fuel is guided to the pressure chamber 134 via the fuel passage 161.

The surface 135b of the control member 135 facing the pressure chamber 134 constitutes a pressure receiving surface for receiving pressure from the supplied fuel introduced into the pressure chamber 134.
A part of. The pressure chamber 13 of the control member 135
4 is larger than the pressure receiving area where the needle valve 26 receives the pressure of the supplied fuel in the fuel reservoir 27.

The hydraulic control unit 45 operates based on a control signal sent from the ECU 111, adjusts the pressure of the hydraulic oil sent from the hydraulic pump 44, and controls the spool valve 14.
3 is configured to generate a control pressure for controlling the operation of the control unit 3. The ECU 111 includes the crank angle sensor 1
2 and an output signal from the accelerator opening sensor 13 to determine whether the engine E is in a predetermined operating state (for example, low rotation and low load), and when the engine E is in a predetermined operating state, A control signal is output to the hydraulic control unit 45 so that the control oil pressure is higher than the operating pressure defined by the urging force of the spring 143a. On the other hand, a control signal is output so that the control oil pressure is lower than the operating pressure defined by the urging force of the spring 143a.

Next, the operation of the fuel injection valve 110 configured as described above will be described with reference to FIG. FIG. 6 is a diagram showing a relationship between the operation state of the spool valve 143 and the lift amount of the needle valve 26.

When the hydraulic control unit 45 lowers the control oil pressure below the operating pressure defined by the urging force of the spring 143a based on the control signal sent from the ECU 111,
The state in which the spool valve 143 discharges the fuel in the pressure chamber 134 through the fuel discharge passage 162 (region C in FIG. 6).
Becomes

The fuel pumped by the distribution type fuel injection pump 102 is supplied as fuel to the fuel passage 28 of the nozzle body 121 through the fuel supply pipe 103, and further sent to the fuel passage 28. The supplied fuel is in the fuel pool 2
It is led to 7. When the pressure of the supplied fuel in the fuel reservoir 27 becomes higher than a predetermined value, the pressure of the supplied fuel in the fuel reservoir 27 acts on the needle valve 26 in the lift direction, and the needle valve 26 starts lifting. Then, the needle valve 26 starts to separate from the valve seat 23.

When the needle valve 26 is lifted to an amount corresponding to the distance L of the gap formed between the piston 131 and the control member 135, the piston 131 and the control member 135 are lifted.
And will come into contact. At this time, the supplied fuel in the pressure chamber 134 is discharged through the spool valve 143 and the fuel discharge passage 162 because the spool valve 143 is in a state of discharging the fuel in the pressure chamber 134. The passage 161 is not shut off by the spool valve 143 and does not lead the supply fuel to the pressure chamber 134, and the pressure in the pressure chamber 134 is lower than the pressure of the supply fuel in the fuel reservoir 27. Therefore, the needle valve 26 continues to lift even after the piston 131 and the control member 135 come into contact with each other, and the lift amount corresponding to the distance L of the gap formed between the piston 131 and the control member 135. The lift will be larger. As described above, when the lift amount of the needle valve 26 is larger than the lift amount corresponding to the distance L of the gap formed between the piston 131 and the control member 135, the fuel injection valve 110
Supplies fuel from the first fuel injection port 22a and the second fuel injection port 22b.

On the other hand, based on the control signal sent from the ECU 111, the hydraulic control
When the pressure is higher than the operating pressure defined by the urging force a, the spool valve 143 guides the supply fuel to the pressure chamber 134 via the fuel passage 161 (the area D in FIG. 6).
Becomes

The fuel pumped by the distribution type fuel injection pump 102 is supplied as fuel to the fuel passage 28 of the nozzle body 121 through the fuel supply pipe 103, and further sent to the fuel passage 28. The supplied fuel is in the fuel pool 2
It is led to 7. When the pressure of the supplied fuel in the fuel reservoir 27 becomes higher than a predetermined value, the pressure of the supplied fuel in the fuel reservoir 27 acts on the needle valve 26 in the lift direction, and the needle valve 26 starts lifting. Then, the needle valve 26 starts to separate from the valve seat 23.

When the needle valve 26 is lifted to an amount corresponding to the distance L of the gap formed between the piston 131 and the control member 135, the piston 131 and the control member 135 are lifted.
And will come into contact. At this time, spool valve 1
Reference numeral 43 denotes a state in which the supply fuel is guided to the pressure chamber 134 via the fuel passage 161. Since the supply fuel is guided to the pressure chamber 134, the pressure of the supply fuel in the pressure chamber 134 is reduced within the fuel reservoir 27. Is maintained at a pressure equivalent to the pressure of the supplied fuel. Furthermore, the area of the surface 135b of the control member 135 is
Since the needle valve 26 is larger than the pressure receiving area for receiving the pressure of the supplied fuel in the fuel reservoir 27, the control member 135
The force acting on the surface 135 b of the needle 131 to push down the piston 131 is greater than the force acting on the needle valve 26 in the lift direction, and the piston 131 and the control member 135
Abuts on, the further lift of the needle valve 26 is limited. Therefore, the needle valve 26
When the piston 131 and the control member 135 come into contact with each other, the lift is limited, and the lift amount of the needle valve 26 corresponds to the distance L of the gap formed between the piston 131 and the control member 135. The lift amount is limited to a so-called pre-lift amount. Thus, the needle valve 26
Is limited to the pre-lift amount (L), the fuel injection valve 110 injects and supplies fuel from the second fuel injection port 22b.

As described above, according to the fuel injection device 101 of the second embodiment, similar to the above-described first embodiment,
When the lift amount of the needle valve 26 is limited to the pre-lift amount (L), the fuel injection valve 110 is connected to the second fuel injection port 2.
Since the fuel is supplied from 2b, the minimum fuel passage area in the fuel injection valve 110 is reduced, and the injection rate can be suppressed. By suppressing the injection rate in this manner, the premixed combustion ratio can be reduced, and a sudden increase in pressure at the beginning of combustion can be suppressed, thereby reducing combustion noise. Further, since the combustion temperature can be lowered, the generation of NOx can be suppressed. On the other hand, the needle valve 26
In the state where the lift amount is larger than the pre-lift amount (L), the fuel injection valve 110 is connected to the first fuel injection port 22a and the second fuel injection port 22a.
Since the fuel is injected and supplied from the fuel injection port 22b, the injection period can be shortened, and the combustion after the short combustion period and less burning can be performed. As described above, since the thermal efficiency is improved in the combustion in which the afterburning is short and the afterburning is small, the output of the engine E can be improved.

Further, the number of fuel injection ports 22 (first fuel injection ports 22a and second fuel injection ports 22b) for injecting fuel is switched according to the lift amount of the needle valve 26. The number of the fuel injection ports 22 (the first fuel injection ports 22a and the second fuel injection ports 22b) that can obtain good engine performance can be appropriately selected according to the state.

As described above, the fuel injection valve 110 includes a control member 135, a pressure chamber 134, a spring 36,
The fuel is pumped from the distribution type fuel injection pump 102 and guided to the fuel reservoir 27. When the pressure of the fuel supplied in the fuel reservoir 27 becomes higher than a predetermined value, the needle valve 26 is turned on. Lift. The pressure chamber 134 through the fuel passage 161 by the spool valve 143
When the supply fuel is introduced into the pressure chamber 134, the pressure in the pressure chamber 134 becomes equal to the pressure of the supply fuel in the fuel reservoir 27, that is, the pressure of the supply fuel acting on the needle valve 26 in the lift direction of the needle valve 26. The piston 131 contacts the control member 135 to limit the lift of the needle valve 26 to the pre-lift amount (L). On the other hand, the spool valve 14
3, the fuel in the pressure chamber 134 is discharged through the fuel discharge passage 162. The pressure in the pressure chamber 134 is equal to the pressure of the supplied fuel in the fuel reservoir 27, that is, the needle valve 26 is The needle valve 26 is further lifted even after the pressure of the supplied fuel acting in the lift direction becomes lower and the piston 131 comes into contact with the control member 135.

Therefore, the lift amount of the needle valve 26 is controlled mainly based on the magnitude of the pressure of the supplied fuel introduced into the pressure chamber 134.
The urging force may be such that the control member 135 can return to the initial position described above. As a result, the urging force of the spring 36 can be set to be smaller than that of the conventional one, and the enlargement of the nozzle body 121 is suppressed, so that the mountability to the engine and the workability of assembling the fuel injection valve 110 are deteriorated. Can be prevented. In addition, the supply fuel is guided to the pressure chamber 134,
Since the pressure of the supplied fuel is used as the pressure of the pressure chamber 134, the needle valve 2 can be used without providing a new hydraulic pressure source.
6, it is possible to control the lift amount, and the power required to generate the hydraulic pressure is smaller than that of the related art. As a result, it is possible to prevent a decrease in engine output and a decrease in fuel efficiency.

The spool valve 143 makes it possible to control the discharge of the fuel in the pressure chamber 134 or the introduction of the supplied fuel to the pressure chamber 134, and to control the pressure in the pressure chamber 134 in synchronization with the fuel injection. It can be performed. Further, a structure capable of controlling the pressure in the pressure chamber 134 is as follows.
With the extremely simple configuration of the spool valve 143, it can be realized simply and at low cost.

Further, since the discharge of fuel in the pressure chamber 134 or the supply of fuel to the pressure chamber 134 is switched by the spool valve 143, the control hydraulic pressure for operating the spool valve 143 is relatively low. The power loss due to the driving of the hydraulic pump 44 for generating the control oil pressure is reduced. As a result, even when the hydraulic pump 44 that generates the control hydraulic pressure is provided, it is possible to suppress a decrease in engine output and a deterioration in fuel efficiency as much as possible.

(Third Embodiment) Next, based on FIG.
A fuel injection device for an internal combustion engine according to a third embodiment of the present invention will be described. FIG. 7 is a schematic diagram illustrating a configuration of the fuel injection device. In the third embodiment, as in the first embodiment, the fuel injection device for an internal combustion engine according to the present invention is applied to a pressure accumulating fuel injection device for a diesel engine.
The fuel injection device 201 of the third embodiment is different from the fuel injection device 1 of the first embodiment in that an electromagnetic lift control valve 243 is used instead of the spool valve 43.
This is different from the embodiment.

The nozzle body 221 of the fuel injection valve 210 of the fuel injection device 201 is provided with a throttle 242 from the pressure chamber 34.
A fuel discharge passage 242 for discharging fuel to the outside of the fuel injection valve 210 via a is provided. Fuel discharge passage 2
A lift control valve 243 is provided at a portion downstream of the throttle section 242a of the throttle control valve 42.
Is configured to operate based on a control signal sent from the ECU 211 to open and close the fuel discharge passage 242 on the downstream side of the throttle portion 242a.

The ECU 211 includes the crank angle sensor 12
And a predetermined operating state of the engine E based on the output signal from the accelerator opening sensor 13 (for example, low rotation and low load).
Is determined, and the lift control valve 243 is
When the engine E is in a predetermined operation state, a control signal is output so that the fuel discharge passage 242 is closed,
When the engine E is not in the predetermined operating state, the control signal is output in synchronization with the output of the control signal to the fuel control valve 41 so that the fuel discharge passage 242 is opened.

When the lift control valve 243 closes the fuel discharge passage 242 based on the control signal sent from the ECU 211, the discharge of fuel from the pressure chamber 34 is prohibited. Thus, in a state where the discharge of fuel from the pressure chamber 34 is prohibited by the lift control valve 243, the fuel control valve 41 opens the fuel discharge passage 39 based on the control signal sent from the ECU 211. Then, the supply fuel in the pressure chamber 37 is reduced by the throttle portion 39a and the fuel control valve 41.
Will be exhausted through.

When the fuel control valve 41 opens the fuel discharge passage 39 and the fuel in the pressure chamber 37 is discharged through the throttle portion 39a and the fuel control valve 41, the pressure of the supplied fuel in the pressure chamber 37 is reduced. Becomes lower than the pressure of the supplied fuel in the fuel reservoir 27, and the pressure of the supplied fuel in the fuel reservoir 27
The acting force in the lift direction acts on the needle valve 26, the needle valve 26 starts lifting, and the needle valve 26 starts to separate from the valve seat 23.

When the needle valve 26 is lifted up to an amount corresponding to the distance L of the gap formed between the piston 31 and the control member 35, the piston 31 comes into contact with the control member 35. At this time, since the discharge of the fuel supplied in the pressure chamber 34 is prohibited by the lift control valve 243, the pressure of the fuel supplied in the pressure chamber 34 is lower than the pressure of the fuel supplied in the fuel reservoir 27. It is kept at the same pressure. Furthermore, since the area of the surface 35b of the control member 35 is larger than the pressure receiving area where the needle valve 26 receives the pressure of the supplied fuel in the fuel reservoir 27, the surface 35b of the control member 35
The force acting on b to push down the piston 31 is
When the force acting on the needle valve 26 in the lift direction becomes larger and the piston 31 and the control member 35 come into contact with each other,
Further lift of the needle valve 26 will be limited. Therefore, when the piston 31 and the control member 35 come into contact with each other, the lift of the needle valve 26 is limited, and the lift amount of the needle valve 26 is
Is limited to a lift amount corresponding to a distance L of a gap formed between the control member 35 and the so-called pre-lift amount. Thus, in a state where the lift amount of the needle valve 26 is limited to the pre-lift amount (L), the fuel injection valve 210
Fuel is injected and supplied from the fuel injection port 22b.

On the other hand, based on the control signal sent from the ECU 211, the lift control valve 243
Is opened and the fuel control valve 41 opens the fuel discharge passage 39, the supply fuel in the pressure chamber 34 is discharged through the fuel discharge passage 242, and the supply fuel in the pressure chamber 37 is released. Fuel is discharged through the throttle portion 39a and the fuel control valve 41. When the supply fuel in the pressure chamber 37 is discharged, the pressure of the supply fuel in the pressure chamber 37 becomes lower than the pressure of the supply fuel in the fuel reservoir 27 as described above, and the supply fuel in the fuel reservoir 27 The needle valve 2
6 acts on the needle valve 26 in the lift direction.
Starts the lift, and the needle valve 26 starts to separate from the valve seat 23.

When the needle valve 26 is lifted up to an amount corresponding to the distance L of the gap formed between the piston 31 and the control member 35, the piston 31 comes into contact with the control member 35. At this time, since the supply fuel in the pressure chamber 34 has been discharged through the fuel discharge passage 242,
The pressure in the pressure chamber 34 is also lower than the pressure of the supplied fuel in the fuel reservoir 27. Accordingly, the needle valve 26 continues to lift even after the piston 31 and the control member 35 come into contact with each other, and the lift amount corresponding to the distance L of the gap formed between the piston 31 and the control member 35 The lift will be larger. in this way,
The lift amount of the needle valve 26 is equal to the piston 31 and the control member 3
In a state in which the lift amount is larger than the lift amount corresponding to the distance L of the gap formed between the first fuel injection port 22 and the second fuel injection port 22b, the fuel injection valve 210 injects and supplies the fuel.

As described above, according to the fuel injection device 201 of the third embodiment, the same operation and effect as those of the fuel injection device 1 of the first embodiment can be obtained.
Compared with the fuel injection device 1 of the embodiment, the spool valve 43, the hydraulic pump 44 for controlling the operation of the spool valve 43, and the hydraulic control unit 45 are not required.
The configuration of the fuel injection device 201 can be extremely simple.

In the first to third embodiments, the fuel injection valves 10, 110, and 210 have a plurality of fuel injection ports, and the fuel is injected and supplied according to the lift amount of the needle valve 26. Although a variable injection port type fuel injection valve in which the number of ports is switched is used, the invention is not limited to this. For example, a pintle nozzle or a throttle nozzle type single hole fuel injection valve may be used.
It is preferable to use a fuel injection valve of a type in which the minimum fuel flow area is variable according to the lift amount of the needle valve.

[0088]

As described above in detail, according to the present invention, the pressure in the lift control chamber acts on the valve member by the lift control chamber pressure adjusting means inhibiting the discharge of fuel in the lift control chamber. When the valve member is lifted by the action of the pressure of the supplied fuel when the pressure is equal to the pressure of the supplied fuel, the lift control member restricts the movement of the valve member in the lift direction by the pressure in the lift control chamber. ,
The valve member contacts the lift control member to limit the lift. Therefore, the lift amount of the valve member is limited to the lift amount corresponding to the distance between the valve member and the lift control member. On the other hand, when the pressure in the lift control chamber is made lower than the pressure of the supplied fuel acting on the valve member by discharging the fuel in the lift control chamber by the lift control chamber pressure adjusting means, the valve member acts on the pressure of the supplied fuel. When the valve member lifts, the valve member comes into contact with the lift control member, but the pressure in the lift control chamber is reduced, and the lift control member is also movable in the lift direction of the valve member. Therefore, the lift is further increased than the lift amount corresponding to the distance between the valve member and the lift control member.

The control of the lift amount of the valve member is performed based on the magnitude of the pressure in the lift control chamber as described above, and the urging force of the urging force applying member returns the lift control member to the initial position. The urging force of the urging force applying member can be set smaller than that of the above-described conventional one. As a result, it is possible to suppress an increase in the size of the nozzle body and prevent deterioration in mountability to the engine and assembly workability of the fuel injection device.

Further, the supply fuel is guided to the lift control room,
Since the pressure of the supplied fuel is used as the pressure of the lift control chamber, it is possible to control the lift amount of the valve member without providing a new hydraulic pressure source. As a result, the power required to generate the hydraulic pressure becomes smaller than that of the above-described conventional one, and it is possible to prevent a decrease in engine output and a deterioration in fuel efficiency.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of a fuel injection device for an internal combustion engine according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between an open / closed state of a spool valve, an open / closed state of a fuel control valve, and a lift amount of a needle valve in the fuel injection device for an internal combustion engine according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a main part showing a modified example of a control member included in the fuel injection device for an internal combustion engine according to the first embodiment of the present invention.

FIG. 4 is a plan view showing a modified example of a control member included in the fuel injection device for an internal combustion engine according to the first embodiment of the present invention.

FIG. 5 is a schematic diagram illustrating a configuration of a fuel injection device for an internal combustion engine according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating a relationship between an operating state of a spool valve and a lift amount of a needle valve in a fuel injection device for an internal combustion engine according to a second embodiment of the present invention.

FIG. 7 is a schematic diagram illustrating a configuration of a fuel injection device for an internal combustion engine according to a third embodiment of the present invention.

FIG. 8 is a sectional view showing a conventional fuel injection device for an internal combustion engine.

[Explanation of symbols]

E: Multi-cylinder diesel engine, 1,101,201 ...
Fuel injection device, 8: common rail, 9: fuel supply pipe, 1
0,110,210 ... fuel injection valve, 11,111,21
DESCRIPTION OF SYMBOLS 1 ... ECU, 21, 121, 221, 301 ... Nozzle body, 22, 302 ... Fuel injection port, 22a ... 1st fuel injection port, 22b ... 2nd fuel injection port, 23 ... Valve seat part, 24,
124 ... valve hole, 25, 125 ... guide hole, 26, 303 ...
Needle valve, 27: fuel reservoir, 28: fuel passage, 3
1,131 ... piston, 32, 132 ... rod, 33 ...
Spring, 34, 134 ... pressure chamber, 35, 51, 135 ... control member, 36 ... spring, 37 ... pressure chamber, 38 ... fuel passage,
39: fuel discharge passage, 41: fuel control valve, 42: communication passage, 43, 143: spool valve, 44: hydraulic pump, 45: hydraulic control unit, 52: fuel passage, 102: distribution type fuel injection pump, 103 ... Fuel supply pipe 161, fuel passage 162 fuel discharge passage 242 fuel discharge passage
243 ... lift control valve, 307 ... spring.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02M 47/02 F02M 47/02 61/16 61/16 DL 61/20 61/20 N (72) Invention Person Akinori Saito 41-cho, Yokomichi, Nagakute-cho, Aichi-gun, Aichi Prefecture F-term in Toyota Central R & D Laboratories Co., Ltd. 3G066 AA07 AB02 AC09 AD12 BA16 BA17 BA22 BA25 BA56 BA61 BA67 CC01 CC06T CC08T CC14 CC23 CC28 CC30 CC51 CC56 CC64T CC66 CC67 CC68T CC68U CC70 CD26 DA11 DA16 DC04 DC05 DC14 DC18 DC19

Claims (6)

[Claims] A nozzle body having a fuel injection port for injecting fuel; a valve member held in the nozzle body so as to be liftable, and lifted by the action of pressure of supplied fuel to open the fuel injection port; A lift control member provided at a distance corresponding to a predetermined lift amount from the valve member, and a lift control member capable of coming into contact with the valve member; a lift control member constituting a part of the lift control member; A control chamber; an urging force applying member provided in the lift control chamber for applying an urging force to the lift control member in a direction opposite to a lift direction of the valve member; and discharging fuel in the lift control chamber. The pressure in the lift control chamber is made lower than the pressure of the supply fuel acting on the valve member, and the discharge of the fuel in the lift control chamber is prohibited. The fuel injection system of the pressure in the control chamber internal combustion engine, characterized in that and a lift control chamber pressure adjusting means for an equivalent state and pressure of the supply fuel acting on the valve member. 2. The fuel injection device further includes a fuel control chamber defined by the valve member and the lift control member, through which the supplied fuel is guided, and communicates with the fuel control chamber to control the fuel control. A fuel discharge passage for discharging fuel in the room; and a fuel control valve provided in the middle of the fuel discharge passage to open and close the fuel discharge passage. A communication passage that communicates a portion of the fuel control chamber closer to the fuel control chamber than the fuel control valve with the lift control chamber; and a lift control valve that is provided in the middle of the communication passage and opens and closes the communication passage. The fuel injection device for an internal combustion engine according to claim 1, wherein: 3. The lift control valve is configured by a spool valve that is switched between a state in which the communication path is opened and a state in which the communication path is closed by control hydraulic pressure sent from a hydraulic pressure source. The fuel injection device for an internal combustion engine according to claim 2, wherein 4. The lift control member, wherein a fuel passage for communicating the fuel control chamber with the lift control chamber is closed by the valve member when the valve member contacts the lift control member. The fuel injection device for an internal combustion engine according to claim 2, wherein the fuel injection device is provided at a position. 5. The lift control chamber pressure adjusting means has a lift control valve for selecting a state in which the supplied fuel is guided to the lift control chamber and a state in which the fuel in the lift control chamber is discharged. The fuel injection device for an internal combustion engine according to claim 1, wherein: 6. The lift control valve is provided with a spool valve that is switched to a state in which the supplied fuel is guided to the lift control chamber or a state in which the fuel in the lift control chamber is discharged by control hydraulic pressure sent from a hydraulic pressure source. The fuel injection device for an internal combustion engine according to claim 5, wherein the fuel injection device is configured.