JPH08261114A - Fuel injection nozzle supporting device for internal combustion engine - Google Patents

Abstract

PURPOSE: To enhance the productibity at the time when a fuel injection nozzle is fitted and the workability at the time of replacement. CONSTITUTION: An external thread 3a is formed on the outer circumference of the end part of a nozzle body retainer 3, and an internal thread 7a to be screwed with the external thread 3a is formed on the inner circumference of a nozzle fitting hole 7, and the end surface of the nozzle body retainer 3 is abutted on the end surface of a nozzle tip retainer 4. Further, the basic end part of the nozzle body retainer 3 is extended up to the upper surface of a rocker cover 10, and a width across flat part with which a tool is to be engaged is formed in the base end part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection nozzle support device for an internal combustion engine, and more particularly to a technique for improving productivity when installing a fuel injection nozzle of an internal combustion engine and workability during replacement.

[0002]

2. Description of the Related Art The structure of a conventional fuel injection nozzle support device for a diesel engine, which is an internal combustion engine, is disclosed in Japanese Utility Model Laid-Open No. 59-1.
No. 843667, No. 59-184366, No. 61-74667, and the like. 6A and 6B show a method of mounting the fuel injection nozzle in the conventional fuel injection nozzle support device for an internal combustion engine.

First, as shown in FIG. 6A, a tool 42 such as a spanner is put on the width across flats formed on the upper portion of the fuel injection nozzle 41, and the fuel injection nozzle 41 is rotated to rotate the cylinder head 43.
6 into the nozzle retainer 44 as shown in FIG. 6 (B).
Is fitted to the width across flats to hold down the fuel injection nozzle 41, and the nozzle retainer 44 is fixed to the cylinder head 42 with a stud bolt and a spherical nut. As a result, the fuel injection nozzle 41
Is supported by the nozzle retainer 43, and the fuel injection nozzle 41 is fixed to the cylinder head 43, and airtightness is secured and positioned.

After the fuel injection nozzle 41 is attached to the cylinder head 42, the cylinder head 42 is covered with a rocker cover (not shown).

[0005]

In the conventional fuel injection nozzle support device for an internal combustion engine, the fuel injection nozzle 41 is used.
Since the mounting portion will be provided inside the rocker cover, productivity at the time of mounting the fuel injection nozzle 41 and workability at the time of replacement will be significantly reduced. In particular, this is a problem when the fuel injection nozzle 41 is to be installed substantially upright in the vicinity of the bore center in order to improve combustion.

Further, when trying to increase the number of intake and exhaust valves in order to improve the performance, since the space in the rocker cover is taken up by the valve spring and the camshaft, for example, in a small direct injection diesel engine, the nozzle It becomes difficult to install the retainer and the fixing bolt. The present invention has been made in view of such conventional problems,
An object of the present invention is to provide a fuel injection nozzle support device for an internal combustion engine, which can improve productivity when attaching the fuel injection nozzle and workability when replacing the fuel injection nozzle.

[0007]

Therefore, in the fuel injection nozzle support device for the internal combustion engine according to the invention of claim 1, between the nozzle tip on the tip side and the nozzle body on the base side,
A nozzle tip retainer having a diameter larger than these is provided, the nozzle body is rotatably held on the inner circumference, and abuts on the end surface of the nozzle tip retainer at the tip end surface, and a male screw is formed on the tip end outer circumference, and the base end portion is formed. A width across flats that engages the tool is formed,
Nozzle body retainer extended to the outside of the rocker cover that covers the cylinder head, consisting of a small diameter portion for inserting the nozzle tip and a large diameter portion for inserting the nozzle tip retainer, on the inner circumference of the large diameter portion, And a nozzle mounting hole of a cylinder head in which a female screw to be screwed with the male screw of the nozzle body retainer is formed.

In the fuel injection nozzle support device for the internal combustion engine according to the second aspect of the present invention, the nozzle body retainer is
A two-sided width portion of the base end portion is formed in a stepped shape having an outer diameter larger than a hole penetrating the rocker cover, and is interposed between the two-sided width portion of the nozzle body retainer and the rocker cover. A seal member formed of a substantially cylindrical elastic body is provided, which is crimped by screwing the body retainer into the nozzle mounting hole to seal between the nozzle body retainer and the rocker cover.

In the fuel injection support device nozzle for the internal combustion engine according to the third aspect of the present invention, the groove portion for fitting and fixing the fuel introduction pipe is provided in the upper portion of the rocker cover. Claim 4
In the fuel injection support device nozzle for an internal combustion engine according to the invention described above, an arm having a groove portion for fitting and fixing the fuel introduction pipe is provided, and the arm is fixed to the cylinder head.

In the fuel injection support device nozzle for an internal combustion engine according to a fifth aspect of the present invention, a cylindrical fuel injection nozzle that seals the nozzle body retainer by press-fitting and fixing from the nozzle mounting hole of the cylinder head to the through hole of the rocker cover. I set up a hall. In the fuel injection support device nozzle for an internal combustion engine according to the invention of claim 6, the internal combustion engine comprises:
It is a direct injection diesel engine.

[0011]

According to the structure of the fuel injection nozzle of the internal combustion engine according to the invention of claim 1, the male screw formed on the outer periphery of the tip end portion of the nozzle body retainer is screwed with the female screw of the nozzle mounting hole of the cylinder head. The nozzle body retainer is abutted against the nozzle tip retainer at the tip of the nozzle body retainer by locking the tool to the two-face width portion of the nozzle body retainer extending to the outside of the rocker cover and screwing the nozzle body retainer into the locker cover. The nozzle tip retainer is pressed and fixed. Therefore, the fuel injection nozzle can be attached / detached from the upper portion of the rocker cover, so that it is possible to improve the productivity at the time of attaching the fuel injection nozzle and the workability at the time of replacement. Further, since it is not necessary to dispose a fixing bolt or the like inside the rocker cover, it is possible to realize a simple direct-acting multi-valve mechanism without requiring a space.

According to the structure of the fuel injection nozzle supporting device for the internal combustion engine according to the second aspect of the present invention, the nozzle body retainer is screwed into the nozzle mounting hole so that the seal member is pressed against the nozzle body retainer and the rocker cover. Since the gap is sealed, the sealing property is improved. According to the structure of the fuel injection nozzle supporting device for the internal combustion engine of the third aspect of the invention, since the fuel introduction pipe is fixed to the groove portion of the rocker cover, the fuel injection nozzle can be easily positioned and the high pressure injection is performed. Improves workability when installing pipes.

According to the structure of the fuel injection nozzle supporting device for the internal combustion engine according to the fourth aspect of the present invention, the groove portion into which the fuel introducing pipe is fitted is formed in the arm, and the arm is fixed to the cylinder head. It is possible to improve the positioning accuracy between the fuel supply pipe and the fuel supply pipe. According to the structure of the fuel injection nozzle supporting device of the internal combustion engine according to the invention of claim 5, since the fuel injection nozzle hole is provided independently,
It is possible to reliably ensure the oil tightness and air tightness of the rocker cover, and it is possible to reliably prevent the oil from flowing into the combustion chamber when the fuel injection nozzle is removed.

According to the structure of the fuel injection nozzle supporting device for an internal combustion engine according to the invention of claim 6, when the internal combustion engine is a direct injection type diesel engine, the fixing bolts of the nozzle retainer are not arranged in the rocker cover. It also improves and the effect is great.

[0015]

Embodiments of the present invention will be described below with reference to FIGS. First, the first embodiment will be described. FIG.
FIG. 3 is a sectional view of a cylinder upper portion of, for example, a direct injection diesel engine as a first embodiment. The cylinder head 1 is made of, for example, cast iron or aluminum. The cylinder head 1 is provided with a camshaft 21 and the like, and the upper surface is covered with a rocker cover 10. The rocker cover 10 is elastically supported by the cylinder head 1. ing. A nozzle mounting hole 7 is provided in the bore center of the cylinder head 1 and the rocker cover 10, and the fuel injection nozzle is inserted into the nozzle mounting hole 7 so as to be substantially upright.

The nozzle tip retainer 4 is arranged between the nozzle tip 5 on the front end side and the nozzle body 2 on the base end side and has a larger diameter than these, and the nozzle tip 5 for discharging the fuel into the fuel chamber. Is fixed and the nozzle tip 5 is fixed by screwing into the tip of the nozzle body 2. The nozzle tip 5, the nozzle tip retainer 4, and the nozzle body 2 form a fuel injection nozzle, which are made of, for example, steel.

The nozzle body retainer 3 is formed as a substantially cylindrical member and rotatably holds the nozzle body 2 on the inner circumference of the cylinder, and its tip end surface abuts against the end surface of the nozzle tip retainer 4. Then, the base end portion thereof is extended to the outside of the rocker cover 10 that covers the cylinder head 1, and a two-face width portion that engages with a tool is formed. A male screw 3a is formed on the outer circumference of the tip portion.

The base end of the nozzle body 2 is also a rocker cover.
A fuel spill pipe 12 is arranged to extend to the outside of 10. Further, the nozzle body 2 has a structure in which a fuel introduction pipe 9 is attached at a base end portion in a direction substantially perpendicular to the axis of the nozzle body. The nozzle mounting hole 7 is composed of a small diameter portion into which the nozzle tip 5 is inserted and a large diameter portion into which the nozzle tip retainer 4 is inserted, and the male screw 3a of the nozzle body retainer 2 and a screw thread are screwed on the inner circumference of the large diameter portion. A mating female screw 7a is formed.

The boss of the nozzle mounting hole 7 of the cylinder head 1 is formed so as to be raised from the head upper deck so as to prevent the lubricating oil from flowing into the combustion chamber through the nozzle mounting port when the nozzle is removed. A nozzle gasket 6 is arranged between the bottom of the nozzle mounting hole 7 and the nozzle tip retainer 4. It should be noted that deviation of the surface pressure distribution due to tilting of the fuel injection nozzle and change in surface pressure caused by the difference in thermal expansion due to the difference between the material of the fuel injection nozzle (steel) and the material of the cylinder head 1 (cast iron / aluminum) are minimized. The distance between the gasket surface and the pressing surface of the nozzle gasket 6 is shortened.

The nozzle seal 8 is formed of a substantially cylindrical elastic body and is pressed when the nozzle body retainer 3 is screwed into the nozzle mounting hole 7. The height and thickness of the nozzle seal 8 are set by the nozzle body retainer 3 to the nozzle seal 8 at a screwing position where proper sealing surface pressure is generated on the nozzle gasket 6 when the nozzle body retainer 3 is tightened in the nozzle mounting hole 7. It is selected so that the appropriate deformation can be applied.

As shown in FIG. 2, which is a sectional view taken along the line AA ', of the rocker cover 10, a positioning groove 11 for fixing the fuel introducing pipe 9 is provided. Mating to 11. And, in this fuel introduction pipe 9,
A high pressure injection pipe 22 for supplying fuel is attached.

Next, a method of assembling this fuel injection nozzle and a method of attaching it to the cylinder head 1 and the rocker cover 10 will be described. First, to assemble the fuel injection nozzle, the nozzle tip 5 is attached to the nozzle tip retainer 4.
And insert the nozzle body retainer 3 into the nozzle body 2. Then, the nozzle tip 5 is fixed by screwing the nozzle tip retainer 4 into the nozzle body 2, and the nozzle body retainer 3 is integrated with the nozzle body 2 to be in a rotatable assembly state.

Next, the assembled fuel injection nozzle is attached to the cylinder head 1 and the rocker cover 10. That is, the nozzle seal 8 is attached to the rocker cover 10, and the assembled fuel injection nozzle is
Insert into the nozzle mounting hole 7 via the nozzle gasket 6,
Female screw 7a of nozzle mounting hole 7 and nozzle body retainer 3
Screw together and screw. Further, a tool such as a spanner is engaged with the two chamfered portions of the nozzle body retainer 3, and the nozzle body retainer 3 is screwed into the nozzle gasket 6 to such an extent that an appropriate sealing surface pressure is obtained. As described above, since the height position and the thickness of the nozzle seal 8 are appropriately selected, the nozzle gasket 6 can obtain an appropriate seal surface pressure, and the nozzle body retainer 3 of the nozzle seal 8 can be used at this screwed position. Appropriate deformation is applied and the rocker cover 10 is sufficiently oil-tight and air-tight.

After the fuel injection nozzle is fixed, the fuel introducing pipe 9 is fitted into the positioning groove 11 of the rocker cover 10 and inserted into the nozzle body 2 from a direction substantially perpendicular to the axis of the nozzle body. Insert the high pressure injection pipe. According to this structure, the female screw 7a formed on the inner periphery of the nozzle mounting hole 7 and the male screw 3a formed on the outer periphery of the tip end portion of the nozzle body retainer 3 are screwed together to form the base end portion of the nozzle body retainer 3. Since the fuel injection nozzle can be attached / detached from the upper portion of the rocker cover 10 by engaging the tool with the width across flats formed in the above, the productivity at the time of attaching the fuel injection nozzle and the maintainability at the time of replacement are improved.

Further, in the DOHC valve train layout, the camshafts 21 can be made narrower, and a simple direct acting multiple valve train can be realized. In particular, since the compression ratio is set high in the diesel engine, it is possible to widen the interval between the pentroof combustion chamber and the cam shaft, which are used in the gasoline engine and have a wide valve angle.

Further, the sealing surface pressure of the gasket 6 at the tip of the nozzle is generated by the nozzle body retainer 3 pushing the nozzle tip retainer 4. However, since the distance between the nozzle gasket 6 surface and the pressing surface is short, the fuel injection nozzle falls. It is possible to reduce unevenness in the surface pressure distribution and changes in the surface pressure caused by the difference in thermal expansion due to the difference between the material of the fuel injection nozzle (steel) and the material of the head (cast iron / aluminum), and the sealing performance is improved.

Further, since the fuel introduction pipe provided in a direction substantially perpendicular to the nozzle body axis can position the nozzle in the axis rotation direction at a position distant from the nozzle body axis, the positioning accuracy is improved. Especially in direct injection diesel engines where it is common to use multi-hole nozzles, positioning is easy not only when the nozzle is tilted or offset, but also when the nozzle is upright at the bore center. Therefore, it is possible to accurately set the positional relationship between the glow plug and the spray, which has a great influence on startability and combustion performance.

Further, since the mounting position of the high pressure injection pipe 22 can be extended to the end surface of the head, the bending process of the high pressure injection pipe can be simplified, there is no interference with the fuel spill pipe 12, and the high pressure injection pipe 22
The installation workability of is improved. Further, since the boss of the nozzle mounting port 7 is structured to be raised from the head upper deck, it is possible to prevent the lubricating oil from flowing into the combustion chamber through the nozzle mounting hole 7 when the fuel injection nozzle is removed.

Next, a second embodiment will be described. In this embodiment, the positioning groove of the fuel introduction pipe is formed in a separate member, and this separate member is fixed to the cylinder head. FIG. 3 and FIG. 4 show a sectional view taken along the line BB ′ of the supporting device of the second embodiment, respectively. The same elements as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

In FIGS. 3 and 4, the positioning groove 11 of the fuel introducing pipe 9 is provided with an arm 31 which is a member separate from the cylinder head 1.
The arm 31 is fixed by a bolt 33 and a nut 34 of a boss 32 provided on the cylinder head. With this configuration, the cylinder head 1 is compared with the first embodiment in which the positioning is performed by the positioning groove 11 provided in the rocker cover 10 elastically supported by the cylinder head 1.
Since the groove portion 11 for fitting and fixing the fuel introduction pipe 9 is formed in the arm 31 fixed to, the positioning accuracy can be improved.

Next, a third embodiment will be described. In this embodiment, nozzle holes are independently provided outside the fuel injection nozzle. FIG. 5 shows a third embodiment. The same elements as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 1, the nozzle hole 35 has a cylindrical shape independently provided outside the fuel injection nozzle from the nozzle mounting hole 7 of the cylinder head 1 to the through hole of the rocker cover 10. As described above, by providing the nozzle hole 35, the oil-tightness and air-tightness of the rocker cover 10 can be more reliably ensured.

Further, it is possible to reliably prevent the oil from flowing into the combustion chamber when the nozzle is removed.

[0034]

As described above, in the fuel injection nozzle supporting device for the internal combustion engine according to the invention of claim 1, the fuel injection nozzle can be attached and detached from the upper part of the rocker cover, and the productivity at the time of attaching the fuel injection nozzle and the time of replacement can be improved. The workability can be improved, and since it is not necessary to dispose a fixing bolt or the like inside the rocker cover, it is possible to realize a simple direct-acting multi-valve mechanism without requiring a place.

According to the structure of the fuel injection nozzle supporting device for the internal combustion engine according to the second aspect of the present invention, the seal member seals between the nozzle body retainer and the rocker cover, so that the sealing performance is improved. According to the configuration of the fuel injection nozzle support device for the internal combustion engine according to the invention of claim 3,
The fuel injection nozzle can be easily positioned, and workability at the time of mounting the high-pressure injection pipe can be improved.

According to the structure of the fuel injection nozzle supporting device for the internal combustion engine according to the fourth aspect of the present invention, the arm fixed to the cylinder head is formed with the groove for fitting the fuel introducing pipe. The positioning accuracy between the fuel supply pipe and the fuel supply pipe can be improved. According to the configuration of the fuel injection nozzle support device for the internal combustion engine according to the invention of claim 5,
Since the fuel injection nozzle hole is provided independently, the oiltightness and airtightness of the rocker cover can be reliably ensured, and the inflow of oil into the combustion chamber when the fuel injection nozzle is removed can be reliably prevented.

According to the structure of the fuel injection nozzle supporting device of the internal combustion engine according to the invention of claim 6, when the internal combustion engine is a direct injection type diesel engine, the fixing bolts of the nozzle retainer are not arranged in the rocker cover. It also improves and the effect is great.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line A-A ′ in FIG.

FIG. 3 is a sectional view showing a second embodiment of the present invention.

FIG. 4 is a sectional view taken along the line B-B ′ of FIG.

FIG. 5 is a sectional view showing a third embodiment of the present invention.

FIG. 6 is an explanatory view of a conventional fuel injection nozzle mounting method.

[Explanation of symbols]

 1 Cylinder head 2 Nozzle body 3 Nozzle body retainer 4 Nozzle tip retainer 5 Nozzle tip 8 Nozzle seal 9 Fuel introduction pipe 10 Rocker cover 11 Positioning groove

Claims (6)

[Claims] 1. A nozzle tip retainer having a diameter larger than these is provided between a nozzle tip on the tip side and a nozzle body on the base end side, and the nozzle body is rotatably held on the inner circumference of the nozzle tip retainer. A nozzle body retainer that is in contact with the end face at the front end face, has a male screw formed on the outer periphery of the front end portion, has a two-face width that engages with a tool at the base end portion, and extends outside the rocker cover that covers the cylinder head And a large-diameter portion into which the nozzle tip is inserted and a large-diameter portion into which the nozzle tip retainer is inserted, and a female screw that engages with the male screw of the nozzle body retainer is formed on the inner circumference of the large-diameter portion. And a nozzle mounting hole for a cylinder head, and a fuel injection nozzle support device for an internal combustion engine. 2. The nozzle body retainer has a base end portion 2
The face width portion is formed in a stepped shape having a larger outer diameter than the hole penetrating the rocker cover, and is interposed between the two face width portions of the nozzle body retainer and the rocker cover to attach the nozzle body retainer to the nozzle. The internal combustion engine according to claim 1, further comprising: a seal member formed of an elastic body having a substantially cylindrical shape, which seals between the nozzle body retainer and the rocker cover by being crimped by being screwed into the hole. Fuel injection nozzle support device. 3. A fuel injection nozzle support device for an internal combustion engine according to claim 1 or 2, wherein a groove for fitting and fixing a fuel introduction pipe is provided on an upper portion of the rocker cover. 4. The structure according to claim 1, wherein an arm having a groove portion for fitting and fixing the fuel introducing pipe is provided, and the arm is fixed to the cylinder head. Fuel injection nozzle support device for internal combustion engine. 5. A cylindrical fuel injection nozzle hole for press-fitting and fixing from a nozzle mounting hole of the cylinder head to a through hole of a rocker cover to seal a nozzle body retainer is provided. 4. The fuel injection nozzle support device for the internal combustion engine according to any one of 4 above. 6. The internal combustion engine is a direct injection diesel engine according to any one of claims 1 to 5.
5. A fuel injection nozzle supporting device for an internal combustion engine according to claim 6.