JPS6313022B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high pressure fuel pipe connection structure for a fuel injection valve mainly used in a diesel engine.

In recent diesel engines, as shown in FIG. 4, high-pressure fuel oil is passed into the cylinder head 61 from the cylinder head side end face 61a,
Many structures have been adopted in which the power is supplied to the That is, it is possible to avoid disposing the high-pressure pipe 65 in the valve arm chamber 63, which has limited space, and to avoid leakage of fuel oil into the valve arm chamber 63 by connecting the high-pressure pipe 65 to the upper end of the injection valve 62. There is.

However, in the conventional example shown in FIG. 4, an intermediate joint 66 is connected to the injection valve 62, the intermediate joint 66 extends to the cylinder side end surface 61a, and a fuel high pressure pipe 65 is connected to the intermediate joint 66. Therefore, when taking out the injection valve, there are two connections, namely, the connection between the high pressure pipe 65 and the intermediate joint 66, and the connection between the intermediate joint 66 and the injection valve 62.
The connection part must be disassembled, and the work to remove the injection valve is time-consuming. Additionally, since there are two connections, there is a high risk of high-pressure fuel oil leaking.

The present invention aims to solve the above-mentioned problems, and will be explained as follows based on the drawings.

FIG. 1 shows the cylinder head portion of a diesel engine adopting the present invention, and in this FIG.
A fuel injection valve insertion hole 3 that opens into the combustion chamber 2 is formed in the lower half of the cylinder head 1, and a fuel injection valve chamber 4 that is connected to the insertion hole 3 is formed above the insertion hole 3. The valve chamber 4 has a large volume that can comfortably accommodate the fuel injection valve 5, and is formed to open upward. The valve chamber 4 has a cylinder head side end surface 1.
A horizontal high-pressure pipe storage chamber 6 extending to a is in communication. Below the storage chamber 6, an oil leakage passage 7 is formed that extends horizontally from the cylinder head side end surface 1a to below the valve chamber 4, and at the end of the oil leakage passage 7 on the valve chamber 4 side, an upper opening that extends upward is formed. An oil leak inlet hole (oil leak inlet part) 8 is formed.

A vertical connector 10 is fitted and connected to the entrance hole 8 from above.

A nozzle tightening nut 1 is attached to the lower end of the fuel injection valve 5.
1, a nozzle body 13 is fixed via a spacer 12, the lower half of the injection valve 5 and the nozzle body 13 are inserted into the insertion hole 3 from above, and the lower edge of the nozzle body protrudes into the combustion chamber 2. ing. The needle valve 14 in the nozzle body 13 is connected to the coil spring 1
5 through the lower spring receiver 16, and the upper end of the coil spring 15 is biased downward through the upper spring receiver 17.
The injection amount adjustment rod 18 is engaged with the injection amount adjustment rod 18 via the injection amount adjustment rod 18.
The upper end of the rod 18 is screwed into the upper end female thread of the injection valve 5 and has a long head 18a that projects into the valve arm chamber 19. The rod 18 is locked in a proper vertical position by a lock nut 20.

A valve chamber cover 22 is fitted to the upper end of the injection valve 5 via an O-ring 21, an annular holding plate 25 is in contact with the upper end surface of the injection valve 5, and there is a gap between the holding plate 25 and the cover 22. A coil spring 24 is attached, and a presser plate 25
is pressed downward by the fuel injection valve holding fitting 26. That is, the injection valve 5 is pressed downward by the holding metal fitting 26 and the holding plate 25, and at the same time, the valve chamber cover 22 is pressed downward via the coil spring 24. 23 is Patsukin. The presser metal fitting 26 is fixed to the upper surface of the cylinder head 1 by bolts 27, and the tip portion (the left end portion in FIG. 1) of the presser metal fitting 26 is formed in a fork shape so as to sandwich the long head 18a.

In the valve chamber of the injection valve 5, a male threaded part (high pressure pipe connection part) 28 facing the high pressure pipe storage chamber 6 and an oil leakage outlet hole (oil leakage outlet part) 29 opening downward are formed. 29 is fitted and connected to the connector 10. A fuel passage 30 within the male threaded portion 28 communicates with an annular passage 32 of the nozzle body 13 via a passage 31 within the injection valve 5 . The outlet hole 29 communicates between the outer circumferential surface of the rod 18 and the inner circumferential surface of the rod insertion hole 34 via a passage 33. Note that the outlet hole 29 is formed on the back side of the page of FIG. 1 from the male threaded portion 28, and both 28 and 29 are on the same plane (on the page of FIG. 1) and do not overlap.

A tightening tube 35 is inserted into the storage chamber 6, and the tightening tube 3
A fuel high pressure pipe 36 is inserted into the inside of the tightening pipe 35.
By screwing into the male threaded part 28, the high pressure pipe tip tapered part 36a is connected to the conical receiving hole 28a of the male threaded part 28 via the inward flange 35a and the ring 40.
is forcing it on. Further, an outward flange 36b is formed at the left end portion of the tightening tube 35 in FIG. 1, and the gasket 43 is pressed against the storage chamber side lid 41 by the outward flange 36b. The storage chamber side cover 41 is pressed against the cylinder head side end surface 1a by bolts. A drain hole 42 communicating with the storage chamber 6 is formed at the lower end of the side lid 41, and the drain hole 42 communicates with the drain tank. The high pressure fuel pipe 36 is connected to a fuel injection pump.

A check valve main body 45 is screwed onto the end surface of the oil leak passage 7 on the cylinder head side, and a return pipe 46 is connected to the check valve main body 45, and the return pipe 46 communicates with the fuel tank. The check valve main body 45 includes a check valve mechanism consisting of a ball 47, a valve spring 48, and a spring retaining screw 49, and is configured to allow oil to pass only from the oil leak passage 7 to the return pipe 46.

In FIG. 1, 55 is a cooling water jacket, and 56 is a valve arm chamber cover. Reference numerals 70 and 71 are O-rings fitted to the lower and upper parts of the connector 10. Note that the valve arm chamber 19 is filled with a lubricating oil atmosphere.

When using a cooling type nozzle (not shown), a cooling oil pipe insertion hole 50 extending from the injection valve chamber 4 to the cylinder head side end surface 1a is formed above the storage chamber 6, and a cooling oil pipe inserted into the insertion hole 50 is formed. The oil pipe 51 is fitted and connected to the inside of the valve chamber of the injection valve 5 and communicates with a cooling oil passage (not shown) in the injection valve 5 .

Fuel supplied from the fuel injection pump to the high-pressure pipe 36 is sent to the annular passage 32 through passages 30 and 31, and is sent to the combustion chamber 2 through the tip of the needle valve 14.
is injected into.

Fuel (leakage oil) leaking into the injection valve, such as the spring chamber 15a, enters the oil leakage passage 7 from between the rod 18 and the rod insertion hole 34 through the passage 33, the outlet hole 29, the connector 10, and the hole 8. The oil enters the return pipe 46 from the oil passage 7 via the ball 47 in the check valve body 45 and returns to the fuel tank.

When fuel leaks from the male threaded portion 28 or the outlet hole 29, the leaked fuel flows from the valve chamber 4 through the storage chamber 6 into the drain hole 42 and is sent to the drain tank. That is, it does not flow into the valve arm chamber 19. Furthermore, even if cooling oil leaks from the connection between the cooling oil pipe 51 and the injection valve 5, the leaked cooling oil will be removed from the drain hole 4.
2 and does not flow into the valve arm chamber 19.

When installing the injection valve 5, etc., first press fit the connector 10 into the oil leakage outlet hole 29, insert the valve unit consisting of the injection valve 5, nozzle body 13, etc. into the valve chamber 4 from above, and insert the lower half of the valve unit into the valve chamber 4 from above. into insertion hole 3. At this time, the inlet hole 8 and the outlet hole 29 are fitted and connected via the connector 10. This also positions the injection valve 5 around the central axis.
Next, fit the valve chamber cover 22 onto the injection valve 5 and press the spring 2.
4 and the holding plate 25 are attached, and the injection valve 5 is held down by the holding fitting 26, and at the same time, the spring 2
4 and press the lid 22 down.

The high pressure pipe 36 is inserted into the storage chamber 6 together with the clamping pipe 35 from the cylinder head side end face 1a, and the clamping pipe 35
By screwing into the male threaded portion 28, the high pressure pipe 3
The tip tapered portion 36a of the injection valve 6 and the conical receiving hole 28a of the injection valve 5 are directly connected.

Also, the cooling oil pipe 51 has an end surface 1a on the cylinder head side.
It is inserted into the insertion hole 50 and is fitted and connected to the receiving hole 58. The end surface of the cooling oil pipe 51 on the cylinder head side is screwed into the female threaded portion of the hole 50. Injection valve 5
When removing the fuel high pressure pipe 36, the tapered part 36a and the receiving hole 28a are separated by removing the tightening pipe 35 from the male threaded part 28. Just that is enough.

FIG. 2 shows a second embodiment, in which the present invention is applied to a modified cylindrical fuel injection valve 5. The injection valve 5 shown in FIG. 2 is integrally provided with a valve chamber cover 5a. Note that parts corresponding to those in FIG. 1 are given the same numbers as in FIG. 1.

FIG. 3 shows a third embodiment, in which the present invention is applied to an eccentric cylindrical fuel injection valve 5. In the injection valve 5 of FIG. 3, the eccentric cylindrical enlarged portion 5b has an O-ring
It fits into the inner peripheral surface of the valve chamber 4 via 3. A male threaded portion is formed at the inner end of the cylinder head of the clamping tube 35, and is screwed into the horizontal female threaded portion 28' of the injection valve 5. 28'a is a conical receiving hole for high pressure pipe connection, and 74 is a drain passage. Note that parts corresponding to those in FIG. 1 are given the same numbers as in FIG. 1.

A conical receiving hole 28a for connecting a horizontal high-pressure pipe isolated from the valve arm chamber 19 and a threaded portion 28 coaxial with the receiving hole 28a are formed in the fuel injection valve 5 disposed in the center of the cylinder head 1; The tightening tube 35 is inserted horizontally into the cylinder head 1 from the cylinder head side end surface 1a, and one end of the tightening tube 35 is made to protrude outward from the cylinder head side end surface so that it can be rotated from outside the cylinder head. Attachment tube 35
A high-pressure fuel pipe 36 connected to a fuel injection pump is inserted horizontally into the clamping pipe 35 from the end surface 1a on the cylinder head side, and the tapered end 36a of the high-pressure fuel pipe 36 is directly inserted into the clamping pipe 35. Injector valve 5
The tapered part 36a of the high pressure pipe 36 is fitted into the receiving hole 28a with the tightening pipe 35 by fitting the threaded part of the tightening pipe 35 into the threaded part 28 of the injection valve 5.
It has the following advantages. That is,... (1) Since the high-pressure pipe 36 is directly connected to the injection valve 5 without using the intermediate joint 66 (Fig. 4), etc., the high-pressure pipe 36 can be connected directly to the injection valve 5 by disassembling one connection when removing the injection valve. 36 can be removed from the injection valve 5, and the work of removing the injection valve does not take much time. Of course, the work of installing the injection valve does not take much time.

To explain in detail, the high pressure pipe 35 can be directly attached to and removed from the injection valve 5 by simply rotating the tightening pipe 35 from the outside of the cylinder head 1, making disassembly and assembly work such as when inspecting the injection valve 5 extremely easy. be.

That is, the high pressure pipe 36 is inserted into the cylinder head without using an intermediate joint, and directly fitted into the receiving hole 28a of the fuel injection valve 5, and the tightened pipe 3 is inserted into the cylinder head from the cylinder head side end 1a.
5 to the threaded part 28 of the injection valve 5, the tapered part 36a of the high pressure pipe 36 is fixed to the receiving hole 28a via the inward flange 35a of the clamping pipe 35, and the clamping pipe 35 is fixed to the receiving hole 28a. Since it is made to protrude to the outside and can be rotated from the outside, the high pressure pipe 3 can be tightened by simply rotating the tightening pipe 35 from the outside.
6 can be attached to and detached from the injection valve 5, and disassembly and assembly work such as when inspecting the injection valve 5 is extremely easy.

(2) Since it is not necessary to arrange the high-pressure pipe 36 in the valve arm chamber 19, which has limited space, piping work for the high-pressure pipe 36 does not take much time.

(3) Since there is no intermediate joint between the high pressure pipe 36 and the injection valve 5, the risk of leakage of high pressure fuel oil is greatly reduced.

(4) Inside the cylinder head 1, the high pressure pipe 36 and the injection valve 5
Moreover, since the connecting portion is isolated from the valve arm chamber 19, even if high-pressure fuel oil leaks from the connecting portion, it will not flow into the valve arm chamber 19. That is, there is no fear that the lubricating oil atmosphere in the valve arm chamber 19 will be diluted by the fuel oil, and there is no fear that the lubricating action will be adversely affected.

(5) Since the high-pressure fuel pipe is connected to the injection valve 5 through the inside of the cylinder head 1, the path of high-pressure fuel oil from the fuel injection pump to the fuel injection valve 5 can be shortened, and the fuel supply performance is good and the engine Suitable for high performance.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a cylinder head of an internal combustion engine according to the present invention, FIGS. 2 and 3 are longitudinal sectional views showing different embodiments, and FIG. 4 is a longitudinal sectional view of a conventional example. 1... Cylinder head, 1a... Side end surface, 5...
Fuel injection valve, 28a, 28'a...conical receiving hole, 3
6...Fuel high pressure pipe, 36a...Tapered part.

Claims (1)

[Claims] 1 The fuel injection valve 5 located in the center of the cylinder head 1 has a conical receiving hole 28a for connecting a horizontal high-pressure pipe isolated from the valve arm chamber 19 and its receiving hole 28a.
A threaded portion 28 is formed in the same center as the cylinder head, and the tightening tube 35 is inserted laterally into the cylinder head 1 from the cylinder head side end surface 1a, and one end of the tightening tube 35 is made to protrude outward from the cylinder head side end surface. The cylinder head can be rotated from the outside, and the tightening tube 3
A high-pressure fuel pipe 36 connected to the fuel injection pump is inserted horizontally into the clamping pipe 35 from the end face 1a on the cylinder head side, and the tapered end portion 36a of the high-pressure fuel pipe 36 is By directly fitting into the receiving hole 28a of the injection valve 5 and screwing the threaded portion of the tightening tube 35 into the threaded portion 28 of the injection valve 5, the tightening tube 35 connects the tapered portion 36a of the high pressure pipe 36 to the receiving hole. 28
A fuel high pressure pipe connection structure for a fuel injection valve, characterized in that it is configured to be pressed against a.