JP2002310040A - Injection nozzle installing structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection nozzle installing structure causing no deterioration of performance, and no deterioration of maintenability even in a small engine. SOLUTION: A cylinder head cover 3 is arranged so as to cover a cylinder head 2. An injection nozzle hole 4 for inserting the injection nozzle 1, and an installing hole 5 adjacent to this injection nozzle hole 4 are formed in this cylinder head cover 3. A nozzle clamp 6 is fixed to the installing hole 5. The nozzle clamp 6 presses an upper part of the injection nozzle 1 on one end 7, and presses the cylinder head cover 3 on the other end 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a mounting structure for an injection nozzle used in an internal combustion engine.

[0002]

2. Description of the Related Art In general, a fuel injection pump is indispensable in an internal combustion engine, especially in a diesel engine. There are various types of structures of the fuel injection pump, and in each case, the fuel is injected from an injection nozzle provided at the top of the cylinder.

As a mounting structure of the injection nozzle, for example, there is one described in Japanese Utility Model Laid-Open No. 3-122265. As shown in FIG. 6 of the publication, a cylindrical injection nozzle 22 is inserted into a hole 21 provided in a cylinder head 20 so that a small-diameter end of the injection nozzle 22 is exposed in the cylinder. . A cutout portion 27 is formed in the upper part of the injection nozzle 21.

A screw hole 23 is provided in the vicinity of the hole 21, and a shaft 24 is screwed into the screw hole 23. Thus, the nozzle clamp 25 is inserted into the shaft 24 fixed to the cylinder head 20.

[0005] The nozzle clamp 25 is
The arm 26 extends so that a hole into which the hole fits is provided, and the tip of the arm 26 is formed so as to contact the upper surface of the cutout portion 27.

The injection nozzle 21 is fixed in the hole 21 by screwing a nut 28 into the shaft 24 and attaching the nozzle clamp 25 to the shaft 24.

FIG. 7 shows another example of a mounting structure. This shows a state where the cylinder head is viewed from above, and the camshafts 30 and 3 of the cylinder head 20 are shown.
The injection nozzle 22 is inserted at a position sandwiched between zero.

On the other hand, a nozzle clamp 31 having a bolt hole in the center is attached to the cylinder head 20. One end of the nozzle clamp 31 presses the ejection nozzle 22, and the other end presses the sheet 32 fixed on the cylinder head 20.

For this reason, the nozzle clamp 31 is fastened to the cylinder head 20 with bolts (33), so that the injection nozzle 2
2 is pressed against and fixed to the cylinder head 20.

[0010]

However, the above-described method of mounting the injection nozzle has various problems caused by fixing the injection nozzle 22 directly to the cylinder head 20.

That is, the cylinder head 20 is provided with a valve spring 3 operated by the camshafts 30, 30.
5 and blind plugs 34 of the water jacket are dense,
It is difficult to further provide a screw hole 23 here.

[0012] Even if the screw hole 23 can be provided, in a small internal combustion engine having a small space, a valve (provided above the cylinder) is provided by providing such a screw hole 23. In some cases, the included angle of the intake and exhaust valves must be increased. This leads to an increase in the dead volume in the combustion chamber and a decrease in the squish area in the diesel engine, resulting in a problem that the combustion performance is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and it is a technical object of the present invention to provide a mounting structure of an injection nozzle which does not cause deterioration of performance of an internal combustion engine and deterioration of its maintenance. And

[0014]

SUMMARY OF THE INVENTION In order to solve the above-mentioned technical problems, the present invention has a structure for fixing an injection nozzle for injecting fuel of an internal combustion engine to a cylinder head 2 as follows. ing.

That is, a cylinder head cover is provided so as to cover the cylinder head, and the cylinder head cover has an injection nozzle hole through which the injection nozzle is inserted, and a mounting hole adjacent to the injection nozzle hole. A nozzle clamp is fixed to the mounting hole, and the nozzle clamp is formed so that one end thereof presses the upper portion of the spray nozzle while the other end presses the cylinder head cover.

The nozzle clamp may be shaped like a plate clamp, for example, and is fixed with a tightening bolt or the like.

The material of the cylinder head cover can be made of a heat-resistant synthetic resin as well as a metal such as aluminum.

Further, since a stress is applied to a portion of the cylinder head cover where the other end of the nozzle clamp contacts, if the portion is made thick, the durability of the cylinder head cover can be improved.

In the cylinder head cover, it is possible to form irregularities at which the other end of the nozzle clamp comes into contact with the nozzle clamp. As described above, by engaging the two with each other by the unevenness, the nozzle clamp is stabilized at the time of assembling, and the bolt is easily tightened.

After assembly, the nozzle clamp and the cylinder head cover receive a strong pressure, but the unevenness can prevent the displacement.

Here, in the cylinder head cover,
The portion where the other end of the nozzle clamp contacts is the fulcrum, the contact point between the one end of the nozzle clamp and the injection nozzle is the action point, and the cylinder pressure is supported by bolts fastened to the mounting holes. In this way, by dispersing the pressure of the cylinder at a plurality of portions, stress is not concentrated on a specific point, and good durability is obtained as a whole.

It is to be noted that one end of the nozzle clamp can be formed in a forked shape for holding the injection nozzle. With such a shape, the nozzle clamp can be easily removed from the injection nozzle as compared with an annularly formed one surrounding the injection nozzle, and maintenance time can be saved.

As described above, according to the present invention, no processing is required for the cylinder head for mounting the injection nozzle, so that the valve can be freely designed at a sandwiching angle.
Improvement of combustion efficiency and suppression of harmful substance generation can be realized.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The mounting structure of an injection nozzle according to the present invention will be described below in more detail with reference to the embodiments shown in FIGS.

FIG. 1 is a cross-sectional view of a main part, in which injection nozzle holes 2a are formed in the cylinder head 2 by the number of cylinders.
Are arranged.

In this embodiment, a double overhead camshaft type in-line four-cylinder engine is used. The cylinder head 2 is provided with a cylinder head cover 3 made of an aluminum alloy so as to cover the upper surface. Note that a packing 3a is inserted into a joint surface between the cylinder head 2 and the cylinder head cover 3. This packing 3a is formed in an annular shape with heat-resistant rubber.

Here, the cylinder head cover 3 is attached to the cylinder head 2 by attaching bolts 14 provided at both ends of the cylinder head cover 3 so as to penetrate therethrough.

The injection nozzle 1 is formed in a cylindrical shape as a whole, and a fuel injection port (not shown) is provided at a lower end thereof.

On the other hand, in FIGS. 1 to 5, the upper end 1a of the injection nozzle 1 is formed flat. The lower part of the upper end 1a is a small diameter part, and a step part 1b is formed between the lower part and the side surface of the injection nozzle 1 further below.

The injection nozzle 1 includes a solenoid (not shown) for controlling common rail injection.

The injection nozzle 1 is provided on the cylinder head cover 3.
Is provided, and an elliptical dish-shaped recess 3b is provided around the injection nozzle hole 4.
Are formed. The recess 3 b is for escaping a protrusion formed on the injection nozzle 1.

With the above configuration, the injection nozzle 1 can be inserted into and removed from the cylinder head 2 through the injection nozzle hole 4.

The cylinder head cover 3 is further provided with a bolt hole 5 at a position adjacent to the injection nozzle hole 4. The mounting holes 5 are for fixing the nozzle clamp 6 to the cylinder head cover 3 with bolts 10.
A thick portion 5a is formed in a portion of the cylinder head cover 3 where the mounting hole 5 is provided for reinforcement.

The nozzle clamp 6 has a shape like a gourd crushed as a whole, and has a bolt insertion hole 6a at the center thereof. Also nozzle clamp 6
Is formed in a forked shape, and the lower surface of the one end 7 can press down the step portion 1b. Further, the other end 8 of the nozzle clamp 6 has a thin tip,
A small projection 8a is formed on the lower surface.

The bolt insertion hole 6a of the nozzle clamp 6
As shown in FIG. 1, a bolt 10 is inserted and screwed into the mounting hole 5 to push down the injection nozzle 1 to fix it.

At this time, the mounting hole 5 into which the bolt 10 is screwed is attached.
Is preferably as close as possible to the mounting bolts 14 of the cylinder head cover 3 in the arrangement direction of the nozzle clamps 6 with respect to the mounting bolts 14 of the cylinder head cover 3 described above. That is, in FIG. 4, the mounting hole 5 of the nozzle clamp 6 is provided in a range of a predetermined width L in the arrangement direction of the nozzle clamp 6 when the mounting bolt 14 is the center.

In this way, even if the cylinder head cover 3 receives the acting force from the nozzle clamp 6, the distance between the mounting bolt 14 and the mounting hole 5 is short, so that the fixing force of the mounting bolt 14 on the cylinder head cover 3 is sufficient. And the deformation of the cylinder head cover 3 is suppressed.

In the embodiment shown in FIG. 1, the nozzle clamp 6 is fixed by penetrating one bolt. However, the present invention is not limited to this example. For example, a headless bolt may be embedded in the cylinder head cover 3. Alternatively, the bolt insertion hole 6a may be dropped into this. in this case,
It is preferable that a screw is not formed in a portion where the bolt insertion hole 6a of the headless bolt is inserted, and the cylinder is formed in a large-diameter cylindrical shape.
After attaching the nozzle clamp 6 to the headless bolt, it is fixed with a nut (not shown).

A seat portion 11 is formed on the cylinder head cover 3 at a portion where the other end 8 of the nozzle clamp 6 comes into contact with the cylinder head cover 3. Since a strong pressing force is applied to the sheet portion 11,
As shown, it is formed to hold another piece,
It is formed to protrude from the surface of the cylinder head cover 3.

A concave portion 11a is formed in the seat portion 11, and the concave and convex portion 9 is formed by engaging with the convex portion 8a formed on the other end 8, so that the displacement between the two does not occur. ing.

With the above construction, the uneven portion 9 of the cylinder head cover 3 where the other end 8 of the nozzle clamp 6 abuts on the sheet portion 11 is the fulcrum, and the one end 7 of the nozzle clamp 6 and the contact point 36 of the injection nozzle 1 are It becomes an action point, and the injection nozzle 1 is firmly fixed.

In this way, the cylinder pressure accompanying the combustion of the internal combustion engine is borne by two places, the bolt fastened to the mounting hole 5 and the other end 8 of the nozzle clamp 6, so that the pressure is dispersed. be able to.

In mounting the injection nozzle 1,
Drilling into the cylinder head, which was required in the past, is no longer necessary,
No processing is required.

Therefore, it is possible to design the valve sandwiching angle essentially, and it is possible to avoid a decrease in performance.

Further, although the cylinder head cover 3 is attached to the cylinder head 2 with a plurality of bolts, the nozzle clamp 6 is separated from the injection nozzle 1 just by removing these mounting bolts, and the injection nozzle 1 can be removed.

Therefore, maintenance of the injection nozzle 1 becomes extremely easy, and maintenance and inspection of the blind plug and the valve spring become easy.

[0047]

According to the present invention, a mounting hole adjacent to the injection nozzle hole is formed in the cylinder head cover, a nozzle clamp is fixed to the bolt hole, and one end of the nozzle clamp presses the upper portion of the injection nozzle. Since the cylinder head cover is pressed at the end, there is no need to provide a mounting hole or the like around the injection nozzle hole in the cylinder head.

As a result, the degree of freedom in designing the internal combustion engine is increased, and the angle of the valve is not restricted.

Therefore, in particular, in the case of a small internal combustion engine, there is no possibility that the performance is deteriorated and the maintenance is not deteriorated.

If the shape of one end of the nozzle clamp is formed in a forked manner for holding the injection nozzle, the nozzle clamp can be easily removed from the injection nozzle, and the maintenance time can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing a mounting structure of an injection nozzle according to an embodiment of the present invention.

FIG. 2 is a partially sectional perspective view showing a mounting structure of an injection nozzle according to an embodiment of the present invention.

FIG. 3 is a partially sectional perspective view showing a main part of a mounting structure of an injection nozzle according to an embodiment of the present invention.

FIG. 4 is a perspective view showing a mounting structure of an injection nozzle according to an embodiment of the present invention.

FIG. 5 is a perspective view showing an injection nozzle mounting structure according to an embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a conventional injection nozzle mounting structure.

FIG. 7 is a plan view showing another mounting structure of the conventional injection nozzle.

[Explanation of symbols]

 Reference Signs List 1 injection nozzle 2 cylinder head 3 cylinder head cover 4 injection nozzle hole 5 mounting hole 6 nozzle clamp 7 one end of nozzle clamp 8 the other end of nozzle clamp 9 unevenness 10 bolt

Claims (4)

[Claims] In a structure for fixing an injection nozzle for injecting fuel of an internal combustion engine to a cylinder head, a cylinder head cover is provided so as to cover the cylinder head. The cylinder head cover has an injection nozzle hole through which the injection nozzle is inserted. Forming a mounting hole adjacent to the injection nozzle hole and fixing a nozzle clamp in the mounting hole, the nozzle clamp pressing the upper portion of the injection nozzle at one end and pressing the cylinder head cover at the other end. A mounting structure for an injection nozzle, characterized in that: 2. The mounting of the injection nozzle according to claim 1, wherein a position where the cylinder head cover is fixed to the cylinder head and a position of a mounting bolt of the nozzle clamp are located at a shortest distance from each other. Construction. 3. The mounting structure for an injection nozzle according to claim 1, wherein the cylinder head cover has a projection and a depression formed at a position where the other end of the nozzle clamp comes into contact with the nozzle clamp. 4. The mounting structure for an injection nozzle according to claim 1, wherein one end of the nozzle clamp is formed in a forked shape for holding the injection nozzle.