JP2001263192A - Electromagnetic fuel injection nozzle for common rail - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable nozzle hole type fuel injection nozzle for a common rail free to inject spray suitable for a combustion state of an engine without increasing size of an actuator for fuel injection control as well as suitable for a fuel injection system having the common rail which is furnished with a function to carry out fuel injection control by controlling a needle valve 4. SOLUTION: An electromagnetic fuel injection nozzle for a common rail constitutes its characteristic feature of providing a two-way valve 28 having a pressure chamber 51 free to control back pressure of a needle valve 4 by taking notice of providing the two-way valve 28 having the pressure chamber 51 free to control back pressure of the needle valve 4 to receive high pressure fuel from the common rail, a valve body 27 provided in the needle valve 4 free to reciprocate and free to drive the needle valve 4 by driving it in the axial direction, a driveshaft 26 to drive the valve body 27 in the axial direction and a solenoid 25 free to drive the driveshaft 26 in the axial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic fuel injection nozzle for a common rail, and in particular, supplies high-pressure fuel from a fuel accumulator (common rail) to a diesel engine or other internal combustion engines in the form of atomized fuel. The present invention relates to an electromagnetic fuel injection nozzle for a common rail which can reduce the size of a solenoid.

[0002]

2. Description of the Related Art Conventionally, in order to promote combustion in an internal combustion engine, to improve output and fuel efficiency, and to reduce combustion noise and nitrogen oxide (NOx) emissions, an electromagnetic type such as a variable injection hole type fuel injection nozzle has been used. Research and development of fuel injection nozzles are underway. For example, in a fuel injection device disclosed in JP-A-59-18006, a tapered pressure receiving surface is formed at the tip of a needle valve slidably housed in a nozzle body, and a fuel pressure acts on the tapered pressure receiving surface. Then, the valve is opened, and a plurality of injection holes formed in multiple stages in the axial direction at the tip end portion of the nozzle body are selected to inject fuel. Further, as in a fuel injection nozzle disclosed in Japanese Patent Application Laid-Open No. 4-76266, a valve is opened by applying a fuel pressure to a pressure receiving surface of a needle valve, and a plurality of injection holes communicating with holes are formed using a rotary valve. To adjust the opening of the orifice,
A technique for making the injection hole cross-sectional area variable is also being studied. Further, as in the variable injection hole type fuel injection nozzle disclosed in Japanese Patent Application Laid-Open No. 8-193560, a configuration in which a multistage injection hole can be selected by rotating a rotary valve is adopted. Some do.

However, what is conventionally developed is a so-called jerk type fuel injection nozzle in which fuel pressure is lifted by applying fuel pressure to a needle valve to perform fuel injection by opening an injection hole. However, this type of variable injection hole type fuel injection nozzle cannot be immediately applied to a common rail type fuel injection system. That is, in the common rail type fuel injection system, high pressure fuel accumulated in the common rail is always supplied to the fuel injection nozzle, and the needle valve is opened and closed by an actuator such as an electromagnetic valve. Although the injection pressure and the injection amount can be appropriately controlled, it is necessary to control the opening and closing of the needle valve, that is, perform the injection control. However, for example, when a fuel injection nozzle having an injection hole selection mechanism of the type described in Japanese Patent Application Laid-Open No. 8-193560 is considered to be mounted on a common rail type fuel injection system, a function of controlling fuel injection on the fuel injection nozzle side is provided. Therefore, it is necessary to incorporate a mechanism for performing fuel injection control inside the nozzle. That is, as the variable injection hole type fuel injection nozzle for the common rail type fuel injection system, it is necessary to develop a fuel injection nozzle having a function of controlling the fuel injection by driving the needle valve.

[0004] In particular, in a fuel injection nozzle for a diesel engine, the fuel pressure for injection is much higher than that in a gasoline engine.
If the actuator that drives and controls the lift of the needle valve in the common rail fuel injection system is a so-called direct-acting type that directly drives the needle valve, there is a problem that this actuator becomes large. Requires some ingenuity.

[0005] In particular, in a fuel injection nozzle for a diesel engine, it is necessary to inject high-pressure fuel. Therefore, in order to improve fuel efficiency, it is required that the internal fuel seal be good. .

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and is an electromagnetic fuel injection nozzle for a common rail suitable for a fuel injection system having an accumulator (common rail) for storing high-pressure fuel. The task is to provide

Another object of the present invention is to provide a common rail electromagnetic fuel injection nozzle having a mechanism for controlling fuel injection by driving and controlling a needle valve.

Another object of the present invention is to provide an electromagnetic fuel injection nozzle for a common rail in which an actuator for performing fuel injection control is not increased in size.

Another object of the present invention is to provide a common rail electromagnetic fuel injection nozzle capable of changing or selecting the injection hole cross-sectional area and injecting spray suitable for the combustion state of the engine.

Another object of the present invention is to provide an electromagnetic fuel injection nozzle for a common rail with improved sealing performance.

[0011]

That is, the present invention provides a two-way valve having a pressure chamber capable of controlling the back pressure of a needle valve receiving high-pressure fuel from a common rail, and for opening and closing the two-way valve. It focuses on providing a solenoid such as a niria solenoid that can drive the drive shaft in the axial direction, while receiving the supply of high-pressure fuel from a common rail that stores high-pressure fuel, as well as the injection hole and this injection hole. For a common rail having a nozzle body having a connected seat surface, and a needle valve provided reciprocally in the nozzle body and capable of injecting the high-pressure fuel from the injection hole by lifting from the seat surface. An electromagnetic fuel injection nozzle that can control the back pressure of the needle valve that receives high-pressure fuel from the common rail A two-way valve having a pressure chamber, a valve body that is provided reciprocally within the needle valve, and is driven in the axial direction, thereby driving the needle valve. A drive shaft for driving, and a solenoid capable of driving the drive shaft in its axial direction;
The electromagnetic fuel injection nozzle for a common rail is characterized in that the nozzle is provided.

[0012] The two-way valve may be provided at the top of the needle valve.

[0013] An introduction orifice branched from a fuel passage for receiving the high-pressure fuel from the common rail and communicating with the pressure chamber can be formed.

An outlet orifice communicating from the pressure chamber to the low pressure side can be formed.

A mechanical seal portion (a second mechanical seal portion) that opens and closes when the drive shaft is driven can be formed between the pressure chamber and the low pressure side.

A clearance seal (first seal) is provided between the nozzle body and the needle valve to seal a space between the pressure chamber and a fuel storage chamber facing a pressure receiving portion of the needle valve.
(A clearance seal portion) can be formed.

[0017] A clearance seal portion (second clearance seal portion) for sealing between the pressure chamber and the injection hole may be formed between the needle valve and the valve body.

The valve body is a rotary valve. The rotary valve can adjust the relative position with respect to the injection hole and can change the injection hole cross-sectional area of the injection hole.

In the electromagnetic fuel injection nozzle for a common rail according to the present invention, a two-way valve having a pressure chamber capable of controlling the back pressure of a needle valve receiving high-pressure fuel from the common rail is provided, and the two-way valve is opened and closed. The drive shaft that drives the two-way valve for opening and closing can be driven with a small driving force by adopting a configuration that provides a solenoid such as a niria solenoid that can drive the drive shaft in the axial direction. The lift operation of the needle valve in the nozzle body to which high-pressure fuel is supplied can be controlled by a smaller actuator via the valve body, and the whole can be manufactured compact. Further, if a two-way valve is provided at the top of the needle valve having good sealing performance, the responsiveness can be improved, the amount of fuel leakage can be reduced, and the fuel efficiency can be improved. If the valve body is a rotary valve and the injection hole cross-sectional area is variable or a different injection hole cross-sectional area is selected, the injection period, injection pressure, injection amount, etc. of the high-pressure fuel constantly supplied from the common rail can be adjusted. By properly adjusting, it is possible to inject a spray suitable for the combustion state of the engine. Of course, even with an electromagnetic fuel injection nozzle whose injection hole cross-sectional area is not variable,
Spray can be supplied utilizing the characteristics of the common rail.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an electromagnetic fuel injection nozzle for a common rail according to an embodiment of the present invention will be described with reference to FIGS. 1 to 10 taking a variable injection hole type fuel injection nozzle 1 for a common rail as an example. FIG. 1 is a cross-sectional view of a common rail variable injection hole type fuel injection nozzle 1. The common rail variable injection hole type fuel injection nozzle 1 includes a nozzle housing 2, a nozzle body 3, a needle valve 4, and an injection hole. It has a selection mechanism 5, an injection control mechanism 6, and a control circuit 7.

The nozzle housing 2 includes a common rail side housing 8 and a linear solenoid housing 9 (first
), A rotary solenoid housing 10 (second solenoid housing), and a distance piece 11. High-pressure fuel is stored in the common rail 14 (accumulator) from the fuel tank 12 via the fuel pump 13, and high-pressure fuel can be supplied to the fuel inlet 15 formed in the common rail side housing 8. A fuel passage 16 is formed from the fuel inlet 15 to the nozzle housing 2 and the nozzle body 3, and a pressure in a lift direction can be applied to a pressure receiving portion 18 of the needle valve 4 in a fuel storage chamber 17 in the nozzle body 3. 17 to a hole 19 at the tip of the nozzle body 3 (FIG. 4).

The nozzle body 3 includes the retaining nut 2
This is fixed to the nozzle housing 2 by 0, and its front end faces the combustion chamber 21. At the tip of the nozzle body 3, a plurality of injection holes (small diameter injection holes 22 and large diameter injection holes 23) having two different types of injection hole cross-sectional areas (in particular, FIG.
And FIG. 6). The small-diameter injection holes 22 and the large-diameter injection holes 23 are formed alternately, for example, at intervals of 45 degrees, for example, four each.

The needle valve 4 is provided in the nozzle body 3 so as to be able to reciprocate. That is, the needle valve 4 is slidable between the nozzle body 3 and the inner wall surface 3A on the upstream side of the fuel reservoir through the first clearance seal portion 24, and between the needle valve 4 and the inner wall surface 3B on the downstream side of the fuel reservoir. Fuel passage 16
This can be reciprocated in the axial direction.

FIG. 2 is an enlarged sectional view of a main part of the nozzle body 3, the injection hole selection mechanism 5, and the injection control mechanism 6 in the variable injection hole type fuel injection nozzle 1 for the common rail. The injection control mechanism 6 controls the opening and closing of the injection holes (small-diameter injection holes 22 and large-diameter injection holes 23) by driving the needle valve 4 in the axial direction thereof, and controls the linear solenoid 25 (the first solenoid valve 25). A solenoid, a drive shaft 26, a rotary valve 27 (valve body),
It has a two-way valve 28, a shaft spring 29, and a needle valve spring 30. The injection hole selection mechanism 5 includes a rotary solenoid 31 (second solenoid), the drive shaft 26 and the rotary valve 27.

FIG. 3 is an enlarged perspective view of the rotary valve 27, and FIG. 4 is an enlarged sectional view of a main part of the injection hole selection mechanism 5 in a state where the rotary valve 27 is seated in the hole 19 and the needle valve 4 is lifted. 5 is a cross-sectional view taken along the line VV of FIG. 2, and FIG. 6 is a cross-sectional view similar to FIG. 5, in which a rotary valve 27 is integrally formed at the tip of the drive shaft 26, as shown in FIG. I have.

In particular, as shown in FIG.
The fuel passage 16 from the fuel inlet 15 and the small-diameter injection holes 22 and the large-diameter injection holes 22 and the large-diameter injection holes The diameter injection hole 23 can be shut off and opened. The seat part 32 and the seat surface 33 form a first mechanical seal part 34. When the needle valve 4 lifts from the seat surface 33 against the urging force of the needle valve spring 30 (FIG. 2), high-pressure fuel is supplied from the small-diameter injection hole 22 or the large-diameter injection hole 23 to the combustion chamber 2.
Injection into 1 is possible.

As shown in FIGS. 3 and 4, the rotary valve 27 is formed in a conical shape so that the conical seat portion 35 can also seat in the conical concave hole 19, and its circumferential direction is The selection fuel passages 36 are formed at equal angular intervals (90-degree intervals) in the
6 can communicate with the small diameter injection hole 22 or the large diameter injection hole 23.

The drive shaft 26 is provided with an enlarged sealing portion 37 at the base end side (upper side in FIG. 4) of the rotary valve 27.
To form a second clearance seal portion 38 between the needle valve 4 and the inner wall surface 4A. A pressure switching passage portion 39 is provided between the inner wall surface 4A of the needle valve 4 and the upstream side of the seal expanding portion 37 in the drive shaft 26.

The configuration of the rotary valve 27 (valve body) is not limited to the configuration shown in FIG. 3 as long as the fuel passage 16 and the small-diameter injection hole 22 or the large-diameter injection hole 23 can be communicated or selected. Can be adopted.
For example, a rotary valve 40 (valve body) shown in FIG. 7 has a selection fuel passage 41 formed in parallel along a conical seat portion 35. The rotary valve 42 (valve body) shown in FIG. 8 includes an introduction hole 43 formed in the upper surface of the rotary valve 42 and a conical seat 3.
5 can be communicated with the selection hole 44 formed in the opening. It should be noted that a valve body that does not have a variable injection hole cross-sectional area may be employed.

As shown in FIGS. 1 and 2, the linear solenoid 25 (first solenoid) drives the drive shaft 26 and the rotary valve 27 in the axial direction thereof. The head 47 of the drive shaft 26 is attracted to the armature 48 against the biasing force of the shaft spring 29 interposed between the spring seat portion 46 and the armature 48. When the head 47 of the drive shaft 26 is sucked by the armature 48, the drive shaft 26 and thus the rotary valve 27 are lifted in the direction of the hole 19 by the shaft lift amount L1 (FIGS. 1 and 2), as shown in FIG. The rotary valve 27 moves toward the hole 19 by the shaft lift amount L1 and seats in the hole 19. As will be described later with reference to FIGS. 9 and 10, the rotary valve 27 seats in the hole 19,
The two-way valve 28 in the injection control mechanism 6 switches, and the needle valve 4 is lifted.

The rotary solenoid 31 (second solenoid) drives the drive shaft 26 and thus the rotary valve 27 to rotate around its axis, as shown in FIGS. 1 and 2, and a flange member 45 of the drive shaft 26. Via the magnet 49 fixed to
Normally, at the time of an exhaust process or an intake process in the combustion chamber 21 of the engine, the drive shaft 26 is rotated by a predetermined circumferential angle, and the fuel passage 36 for selection in the rotary valve 27 and the small-diameter injection hole 22 or the large-diameter The relative position with respect to the injection hole 23 is controlled and adjusted. For example, as shown in FIG. 5, the selection fuel passage 36 faces the small-diameter injection hole 22, or as shown in FIG. The operator operates whether the fuel passage 36 is exposed. In addition,
If the driving force of the rotary solenoid 31 is set to be sufficiently large, the relative position between the rotary valve 27 and the small-diameter injection hole 22 or the large-diameter injection hole 23 can be increased even in the compression process or the combustion process in which the combustion chamber 21 is in a high pressure state. Position control adjustment operation is possible. FIG. 5 shows a state in which a suitable spray can be ejected at high load and low rotation. FIG. 6 shows a state in which a suitable spray can be ejected at low load and high rotation. In either case shown in FIGS. 5 and 6, the selection fuel passage 36
By rotating and selecting the small-diameter injection hole 22 and the large-diameter injection hole 23 so that they are completely located inside the passage,
Injection can be performed while maintaining the normally circular cross-sectional shape of the small-diameter injection hole 22 and the large-diameter injection hole 23, and the shape and direction of the spray can be normally maintained.

FIGS. 9 and 10 are cross-sectional views of the main part of the two-way valve 28, in which a part of the two-way valve 28 is omitted. FIG. ,
FIG. 10 is a cross-sectional view of an injection state in which the needle valve 4 lifts and performs injection similarly to FIG. As shown in FIGS. 2, 9, and 10, in the two-way valve 28, a pressure chamber 51 is formed at the top of the needle valve 4 through an introduction orifice 50 branched from the fuel passage 16, and the pressure chamber 51 is formed. To the spring chamber 52 of the needle valve spring 30.
Is formed. The pressure chamber 51 and the spring chamber 5
Reference numeral 2 denotes a back pressure of the needle valve 4, and a pressure switching passage portion 3 between the inner wall surface 4 </ b> A of the needle valve 4 and the upstream side of the seal expanding portion 37 in the drive shaft 26.
9 is always in communication. The first clearance seal portion 24 (see FIGS. 1 and 2) is provided between the nozzle body 3 and the needle valve 4 and the pressure chamber 51 and the needle valve 4.
Is sealed with the fuel storage chamber 17 facing the pressure receiving portion 18. Further, the second clearance seal portion 3
Reference numeral 8 (see FIG. 4) seals between the pressure chamber 51 and the injection holes (the small-diameter injection holes 22 and the large-diameter injection holes 23) between the needle valve 4 and the valve body 3.

Along the axial direction of the drive shaft 26,
Further, a seal chamber 53 is formed in communication with the spring chamber 52. A movable seal member 54 attached to the drive shaft 26 and a fixed seal member 56 attached to the sleeve 55 of the spring seat portion 46 are provided in the seal chamber 53.
And are provided. Fixed seal member 56 and movable seal member 5
4, the second mechanical seal portion 57 is formed.
An O-ring 58 is arranged between the fixed seal member 56 and the spring seat 46 and the sleeve 55.

The fixed seal member 56 and the drive shaft 2
There is a low-pressure outlet orifice 59 between the valve spring 6 and the fuel tank 6 at a low pressure side (the fuel tank 12 side) through the spring chamber 60 of the shaft spring 29 and the return passage 61. That is, the second mechanical seal portion 57
The pressure chamber 5 is driven by the drive shaft 26.
Open and close between 1 and low pressure side. The characteristics of the two-way valve 28 mainly depend on the inlet orifice 50 and the outlet orifice 59.
This can be determined by the ratio of the cross-sectional areas of

The control circuit 7 (FIG. 1), based on signals from the load sensor 62 and the rotation speed sensor 63,
The drive control of the linear solenoid 25 (injection control mechanism 6) and the rotary solenoid 31 (injection hole selection mechanism 5) is performed.

In the fuel injection nozzle 1 of the variable injection hole type for common rails having such a configuration, when the inside of the combustion chamber 21 is in a relatively low pressure state, that is, in the exhaust process or the intake process of the engine, the rotary solenoid 31 of the injection hole selection mechanism 5 is used. Is driven to rotate the drive shaft 26 around the axis by a predetermined circumferential angle, so that the selection fuel passage 36 in the rotary valve 27 at the tip of the drive shaft 26 and the small-diameter injection hole in the hole 19 of the nozzle body 3 The state shown in FIG. 5 or FIG. 6 is selected by operating the relative positional relationship with the nozzle 22 or the large-diameter injection hole 23.

The operation of the two-way valve 28 in the injection control mechanism 6 will be described below. In a normal non-injection state, FIG.
2, the head 47 of the drive shaft 26 is pulled upward in FIG. 2 by the urging force of the shaft spring 29 (FIG. 2), and the conical seat portion 35 of the rotary valve 27 is moved from the inner wall surface of the hole 19. The needle valve 4 is seated on the seat surface 33 by the high pressure fuel in the pressure chamber 51 and the spring chamber 52 and the urging force of the needle valve spring 30 because the needle valve 4 is axially separated by the shaft lift amount L1. That is, the pressure chamber 5
1 and the pressure receiving area 51S of the needle valve 4 in the spring chamber 52 (the area obtained by subtracting the diameter of the drive shaft 26 from the diameter of the needle valve 4) corresponds to the seat portion 32 of the needle valve 4 on the seat surface 33 of the nozzle body 3. The pressure receiving area 32S (from the diameter of the needle valve 4 its seat portion 32)
And the urging force of the needle valve spring 30 is applied.
This means that even if both the top facing the pressure chamber 51 and the lower end seating on the seat surface 33 are filled with high-pressure fuel, the seat portion 32 will seat on the seat surface 33. Since the second mechanical seal portion 57 of the seal chamber 53 communicating with the spring chamber 52 by the movable seal member 54 and the fixed seal member 56 is in a closed state, the seal chamber 53 is also in a high-pressure state.

Therefore, the pressure chamber 51 and the spring chamber 52 are in a high pressure state together with the seal chamber 53 and the pressure switching passage section 39 from the introduction orifice 50 together with the fuel passage 16 in the high pressure state. When the sheet portion 32 is seated on the sheet surface 33, the small-diameter injection hole 22 or the large-diameter injection hole 23 is not opened, and there is no injection. The periphery of the rotary valve 27 from the seat portion 32 of the needle valve 4 and the expanding portion 37 for sealing of the drive shaft 26 to the injection holes (small diameter injection holes 22 and large diameter injection holes 23) is in a low pressure state. The orifice 59 and the shaft spring 2 are separated by a second mechanical seal 57.
The spring chamber 60 of No. 9 also communicates with the fuel tank 12 via the return passage 61 (FIG. 1) and is in a low pressure state.

The fuel passage 3 for selecting the rotary valve 27
After the communication state between the small diameter injection hole 22 and the large diameter injection hole 22 or the large diameter injection hole 23 is determined, the linear solenoid 25 in the injection control mechanism 6 is driven to thereby rotate the shaft spring 2.
When the armature 48 sucks the head 47 of the drive shaft 26 against the urging force of the rotary shaft 9, the conical seat portion 35 of the rotary valve 27 as shown in FIGS.
Seats in the hole 19 and the movable seal member 5
4 is separated from the fixed seal member 56, the second mechanical seal portion 57 is opened, and the two-way valve 28 is switched. That is, as shown in FIG. 10 in particular, when the second mechanical seal portion 57 is opened, the pressure chamber 51, the spring chamber 52, the seal chamber 53, and the pressure switching passage 39 are formed by the outlet orifice 59 and the spring chamber. 6
It switches to a low pressure state close to the atmospheric pressure level by communicating with zero. Therefore, the pressure balance in the two-way valve 28 switches, and the needle valve 4 receives the high pressure from the fuel passage 16 and the fuel storage chamber 17 by the pressure receiving portion 18, and the seat surface 3
3 (lift amount L2, FIG. 10);
The 2 or large diameter injection hole 23 can be opened to inject into the combustion chamber 21.

To terminate the fuel injection, the linear solenoid 25 is turned off. This "off"
Energizing drive shaft 26 of shaft spring 29
And the rotary valve 27 rises from the state of FIG. 10, the second mechanical seal portion 57 is closed, and the communication state between the lead-out orifice 59 and the seal chamber 53 is cut off.
The pressures in the seal chamber 53, the spring chamber 52, the pressure chamber 51, and the pressure switching passage 39 are increased again, and the needle valve 4 is lowered to the state shown in FIG.

Thus, the needle valve 4 is driven in the axial direction by the vertical movement of the drive shaft 26 and the rotary valve 27 in the injection control mechanism 6 in the axial direction to open and close the small diameter injection hole 22 or the large diameter injection hole 23. The drive shaft 26 and the rotary valve 27 in the injection hole selection mechanism 5 rotate to select either the small-diameter injection hole 22 or the large-diameter injection hole 23 to change the cross-sectional area of the injection hole. Suitable spray can be injected.

Further, the two-way valve 28 itself is arranged as close to the needle valve 4 as possible, and the base end (pressure chamber 51) and the tip end of the needle valve 4 and the portion close to the rotary valve 27 (the sealing enormous portion) (Around 37), switching between high pressure and low pressure is performed, so that responsiveness is good. That is, the first clearance seal portion 24 (FIG. 2) slidable between the needle valve 4 and the inner wall surface 3A of the nozzle body 3 on the upstream side of the fuel storage chamber, and the sealing enlarged portion 37 of the rotary valve 27 and the needle The slidable second clearance seal portion 38 (FIGS. 4, 9, and 10) slidable between the inner wall surface 4A and the valve 4 has good sealing properties and responsiveness, and reduces the amount of leaking fuel. As a result, fuel efficiency can be improved. Further, the first mechanical seal portion 34 (FIGS. 4 and 9) between the seat portion 32 of the needle valve 4 and the seat surface 33 of the nozzle body 3, and between the fixed seal member 56 and the movable seal member 54. Since the switching between high pressure and low pressure is performed in the second mechanical seal portion 57 (FIGS. 9 and 10), the responsiveness can be improved and the amount of leaking fuel can be reduced.

In addition, the actuators (the linear solenoid 25 and the rotary solenoid 31) for driving the needle valve 4 and the rotary valve 27 do not need to be so large, so that a compact structure can be achieved, and as described above, a favorable configuration can be obtained. Response can be obtained, so that pilot injection or the like can be performed if necessary.

[0044]

As described above, according to the present invention, a two-way valve, a drive shaft and a solenoid are used as a drive mechanism of a needle valve in a variable injection hole type fuel injection nozzle for a common rail connected to a common rail. Since the lift state of the valve can be realized, the entire structure can be made compact, and the characteristics of the common rail that always maintains a high pressure state can be utilized to greatly contribute to the improvement of engine performance. Furthermore, since a sealing mechanism is provided in the vicinity of the needle valve having good sealing properties,
Seal performance and responsiveness can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a common rail variable injection hole type fuel injection nozzle 1 (common rail electromagnetic fuel injection nozzle) according to an embodiment of the present invention.

FIG. 2 shows the tip portion of a nozzle body 3 of a variable injection hole type fuel injection nozzle 1 for a common rail, an injection hole selection mechanism 5,
FIG. 4 is an enlarged cross-sectional view of a main part showing a part of an injection control mechanism 6;

FIG. 3 is an enlarged perspective view of the rotary valve 27;

FIG. 4 is an enlarged sectional view of a main part of the injection hole selection mechanism 5 in a state where the rotary valve 27 seats in the hole 19 and the needle valve 4 is lifted.

FIG. 5 is a sectional view taken along line VV of FIG. 2;

FIG. 6 is a sectional view similar to FIG. 5;

FIG. 7 is a perspective view of a rotary valve 40 according to another example of the present invention.

FIG. 8 is a perspective view of a rotary valve 42 according to another example of the present invention.

FIG. 9 is a cross-sectional view of an essential part showing a configuration of the two-way valve 28 in a non-injection state in which the needle valve 4 does not perform injection in a seat state.

FIG. 10 is a cross-sectional view of the main part of the two-way valve 28, showing the configuration of the two-way valve 28, similar to FIG. 4, in an injection state in which the needle valve 4 lifts and performs injection.

[Explanation of symbols]

Reference Signs List 1 Variable injection hole type fuel injection nozzle for common rail (electromagnetic fuel injection nozzle for common rail, embodiment, FIG. 1) 2 Nozzle housing 3 Nozzle body 3A Inner wall surface of nozzle body 3 on the upstream side of fuel reservoir chamber (FIG. 2) 3B nozzle Inner wall surface of fuel reservoir chamber downstream side of body 3 (FIG. 2) 4 Needle valve 4A Inner wall surface of needle valve 4 (FIGS. 2 and 4) 5 Injection hole selection mechanism 6 Injection control mechanism 7 Control circuit 8 Common rail side of nozzle housing 2 Housing 9 Linear solenoid housing of nozzle housing 2 10 Rotary solenoid housing of nozzle housing 2 11 Distance piece of nozzle housing 2 12 Fuel tank 13 Fuel pump 14 Common rail (pressure accumulator) 15 Fuel inlet 16 Fuel passage 17 Fuel reservoir 18 Needle valve 4 Pressure receiving part of 19 Hole of retaining body 3 20 retaining nut 21 combustion chamber 22 small diameter injection hole (injection hole) 23 large diameter injection hole (injection hole) 24 first clearance seal portion 25 linear solenoid (first solenoid) 26 drive shaft 27 rotary valve (Valve body) 28 Two-way valve 29 Shaft spring 30 Needle valve spring 31 Rotary solenoid (second solenoid) 32 Seat portion of needle valve 4 32S Pressure receiving area of seat portion 32 of needle valve 4 on seat surface 33 of nozzle body 3 (32S <51S, FIGS. 2, 9) 33 Seat surface of nozzle body 3 34 First mechanical seal portion 35 Conical seat portion of rotary valve 27 36 Fuel passage for selecting rotary valve 27 37 Sealing of drive shaft 26 Enormous part 38 Rear seal portion 39 Pressure switching passage portion 40 Rotary valve (valve body, FIG. 7) 41 Selection fuel passage 42 Rotary valve (valve body, FIG. 8) 43 Introducing hole portion 44 Selection hole portion 45 Flange member of drive shaft 26 Spring seat part 47 Head of drive shaft 26 48 Armature 49 Magnet 50 Introduction orifice 51 Pressure chamber 51S Pressure receiving area of needle valve 4 in pressure chamber 51 and spring chamber 52 (32S <51S, FIG. 2) 52 Spring of needle valve spring 30 Chamber 53 Seal chamber 54 Movable seal member 55 Sleeve of spring seat part 46 56 Fixed seal member 57 Second mechanical seal part 58 O-ring 59 Outgoing orifice 60 Spring chamber 61 of shaft spring 29 Circulation path 62 load sensor 63 speed sensor L1 drive shaft 26 (rotary valve 27)
Lift amount of shaft (FIGS. 1 and 2) Lift amount of L2 needle valve 4 (FIG. 10)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02M 61/04 F02M 61/04 F A 61/10 61/10 G 61/16 61/16 K 61/18 330 61/18 330C 61/20 61/20 NF term (reference) 3G066 AA07 AB02 AC09 AD12 BA12 BA17 BA36 BA67 CB01 CC05U CC06T CC06U CC08T CC14 CC18 CC20 CC23 CC26 CC30 CC66 CC67 CC68U CC70 CD10 CE13 CE22 DC01 DC09

Claims (8)

[Claims] 1. A nozzle body having an injection hole and a seat surface connected to the injection hole, receiving a supply of the high-pressure fuel from a common rail storing the high-pressure fuel, and a reciprocatingly provided nozzle body in the nozzle body. A needle valve capable of injecting the high-pressure fuel from the injection hole by lifting from the seat surface, and an electromagnetic fuel injection nozzle for a common rail, the needle valve receiving high-pressure fuel from the common rail. A two-way valve having a pressure chamber capable of controlling a back pressure; a valve body which is provided in the needle valve so as to be able to reciprocate, and which is driven in the axial direction to drive the needle valve; A drive shaft for driving the body in the axial direction, and driving the drive shaft in the axial direction. An electromagnetic fuel injection nozzle for a common rail, characterized in that provided a solenoid capable, the. 2. The electromagnetic fuel injection nozzle for a common rail according to claim 1, wherein the two-way valve is provided at a top of the needle valve. 3. The electromagnetic fuel injection nozzle for a common rail according to claim 1, wherein an introduction orifice branched from a fuel passage receiving the high-pressure fuel from the common rail and communicating with the pressure chamber is formed. 4. An electromagnetic fuel injection nozzle for a common rail according to claim 1, wherein an outlet orifice communicating with the low pressure side from the pressure chamber is formed. 5. The electromagnetic fuel injection nozzle for a common rail according to claim 1, wherein a mechanical seal portion that opens and closes when the drive shaft is driven is formed between the pressure chamber and a low pressure side. 6. A clearance seal portion is formed between the nozzle body and the needle valve to seal a space between the pressure chamber and a fuel accumulation chamber facing a pressure receiving portion of the needle valve. Item 2. An electromagnetic fuel injection nozzle for a common rail according to Item 1. 7. A clearance seal portion is formed between the needle valve and the valve body to seal between the pressure chamber and the injection hole.
An electromagnetic fuel injection nozzle for a common rail as described. 8. The valve body according to claim 1, wherein the valve body is a rotary valve, and the rotary valve is capable of adjusting a relative position with respect to the injection hole and changing an injection hole cross-sectional area of the injection hole. The electromagnetic fuel injection nozzle for a common rail according to claim 1.