JP2020148149A - Internal combustion engine seal structure - Google Patents

Abstract

To prevent water and sand from getting inside a combustion chamber.SOLUTION: An internal combustion engine seal structure comprises: an injector tube which is mounted on a cylinder head with a combustion chamber formed at a lower section therein and has a fuel injection valve inserted into the injector tube so that a tip section thereof is exposed in the combustion chamber; an injector holder which is fixed to the cylinder head and supports the fuel injection valve; and an annular gasket which is mounted on an insertion hole of the injector holder at an interface between the injector tube and the injector holder. The gasket has a first protrusion section which is protruded toward a center of an annular shape so as to be pressed against an outer peripheral wall of the injector tube and a second protrusion section which is upwardly protruded so as to be brought into contact with a flange section, installed above the injector holder of the fuel injection valve, from beneath the same.SELECTED DRAWING: Figure 3

Description

The present invention relates to a seal structure of an internal combustion engine.

Conventionally, fuel injection is provided with a lip seal between a sleeve (hereinafter referred to as "injector tube"), which is a tubular member into which a fuel injection valve for injecting fuel into a cylinder of an internal combustion engine is inserted, and a cylinder head cover. The seal structure of the valve is known (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2005-155155

However, the seal structure of the fuel injection valve of Patent Document 1 may allow water, sand, or the like to enter the injector tube. If water or sand has entered the injector tube, the water or sand that has entered the injector tube will enter the combustion chamber when the fuel injection valve is removed from the injector tube, such as when replacing the fuel injection valve. there is a possibility.

Therefore, it is an object of the seal structure of the internal combustion engine disclosed in the present specification to prevent water, sand, etc. from entering the combustion chamber.

The seal structure of the internal combustion engine disclosed in the present specification is mounted on a cylinder head having a combustion chamber formed at a lower portion, and the fuel injection valve is provided so that the tip of the fuel injection valve is exposed to the combustion chamber. An annular shape provided between the injector tube to be inserted, an injector holder fixed to the cylinder head and supporting the fuel injection valve, and an insertion hole provided in the injector holder, and provided between the injector tube and the injector holder. The gasket has a first protrusion that protrudes inward of the annular shape and presses the outer peripheral wall surface of the injector tube, and protrudes upward from the injector holder of the fuel injection valve. Also has a second protrusion that comes into contact with the flange portion provided above from below.

The seal structure of the internal combustion engine is provided adjacent to the flange portion with which the second protrusion abuts, and may further include a shielding portion that regulates the angle of incidence of the water flow directed at the gasket.

According to the seal structure of the internal combustion engine disclosed in the present specification, it is possible to prevent water, sand and the like from entering the combustion chamber.

FIG. 1 is an exploded view showing a part of parts arranged around the cylinder head of the internal combustion engine of the embodiment. FIG. 2 is a cross-sectional view of a portion of the internal combustion engine of the embodiment provided with the seal structure. FIG. 3 is an enlarged cross-sectional view showing the periphery of the upper end portion of the injector tube in the embodiment. 4 (A) is a plan view of the first gasket, FIG. 4 (B) is a sectional view taken along line AA in FIG. 4 (A), and FIG. 4 (C) is a bottom view of the first gasket. .. FIG. 5 is an enlarged cross-sectional view showing the periphery of the upper end portion of the injector tube in the modified example. FIG. 6 is an enlarged cross-sectional view showing the periphery of the upper end portion of the injector tube in still another modified example.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, in the drawings, the dimensions, ratios, etc. of each part may not be shown so as to completely match the actual ones. In addition, some drawings may be drawn with details omitted.

(Embodiment)
The seal structure of the present embodiment includes the injector tube 2 and the injector holder 5 shown in FIG. 1, and the flange portion 10a included in the first gasket 6 and the fuel injection valve 10. Referring to FIG. 1, the cylinder head 1 for an in-line 4-cylinder engine is provided with four injector tubes 2 at the center in the width direction along the cylinder arrangement direction. The cylinder head 1 is provided with a spark plug tube 3 alongside the injector tube 2 for each cylinder. Referring to FIG. 2, a combustion chamber 1a is formed in the lower part of the cylinder head 1, and the injector tube 2 is press-fitted into the first mounting hole 1b provided in the cylinder head 1 and communicating with the combustion chamber 1a. Has been done. The spark plug tube 3 is provided in the cylinder head 1 and is press-fitted into the second mounting hole 1c communicating with the combustion chamber 1a.

Referring to FIG. 1 again, the cam cap 4 is attached to the cylinder head 1. Further, an injector holder 5 is attached to the cam cap 4. Further, a high-pressure delivery 8 that supplies high-pressure fuel to the fuel injection valve 10 is attached to the upper side of the injector holder 5. The injector holder 5 is fixed to the cam cap 4 by the bolt 7. The high pressure delivery 8 is fixed to the cam cap 4 together with the injector holder 5 by the bolt 9. The injector holder 5 is fixed to the cylinder head 1 via a cam cap 4. In the present embodiment, the cam cap 4 and the injector holder 5 are separately provided and combined, but the cam cap 4 and the injector holder 5 may be integrated and configured as one component. The cylinder head cover 12 is omitted in FIG. Further, in FIG. 1, valve operating systems such as a camshaft, an intake valve and an exhaust valve are also omitted.

The injector holder 5 is provided with four insertion holes 5a along the cylinder arrangement direction. A first gasket 6 is attached to the insertion hole 5a. With reference to FIGS. 2 and 3, the first gasket 6 is provided between the injector holder 5 and the injector tube 2 at the upper edge of the injector tube 2.

Referring to FIGS. 4 (A) to 4 (C), the first gasket 6 is an annular member, and has a flange portion 6a extending in a plane and a tubular portion 6b extending downward from the inside of the flange portion. To be equipped. Further, the first gasket 6 includes a first protrusion 6c protruding inward of the annular shape and a second protrusion 6d protruding upward. The first gasket 6 is made of a conventionally known material having excellent oil resistance, abrasion resistance, and aging resistance, and the first protrusion 6c and the second protrusion 6d have elasticity. The first gasket 6 is fitted into the insertion hole 5a so that the outer peripheral surface of the tubular portion 6b is in close contact with the inner peripheral surface of the insertion hole 5a. As a result, the oil in the cylinder head 1 is prevented from leaking to the outside through between the insertion hole 5a and the first gasket 6.

Referring to FIGS. 1 to 3 again, the fuel injection valve 10 includes a flange portion 10a extending in the radial direction toward the side closer to the high pressure delivery 8. The flange portion 10a is located above the injector holder 5 in a state where the fuel injection valve 10 is inserted into the injector tube 2 and the high-pressure delivery 8 is attached to the injector holder 5. As shown in FIG. 2, the fuel injection valve 10 is urged toward the combustion chamber 1a by the clamp spring 11. The clamp spring 11 is clamped between the high-pressure delivery 8 and the fuel injection valve 10 in a compressed state. The fuel injection valve 10 is in a state of being pushed toward the combustion chamber 1a by the elastic force exerted by the clamp spring 11. The first protrusion 6c presses the outer peripheral wall surface of the injector tube 2, and the second protrusion 6d abuts on the flange portion 10a from below.

The first protrusion 6c is provided on the inner peripheral wall surface of the tubular portion 6b, and projects toward the inside of the annular shape. As a result, the first protrusion 6c presses the outer peripheral wall surface of the injector tube 2, maintains the sealing property, and prevents the oil in the cylinder head 1 from leaking to the outside. The first protrusion 6c absorbs the positional deviation (axis deviation) of the injector tube 2 in the radial direction by pressing the outer peripheral wall surface of the injector tube 2. It suffices if all four injector tubes 2 are accurately positioned, but even if any of the injector tubes 2 is misaligned, the first protrusion 6c absorbs the misalignment. As a result, the sealing property is maintained.

The second protrusion 6d projects upward from the collar portion 6a. The second protrusion 6d has a shape that expands outward as it goes upward. Since the second protrusion 6d comes into contact with the flange portion 10a included in the fuel injection valve 10 urged toward the combustion chamber 1a by the clamp spring 11, the second protrusion 6d is also pushed toward the combustion chamber 1a and has a shape. May change. However, since the second protrusion 6d has a shape that spreads outward, it can maintain a state of being in close contact with the flange portion 10a even if it is pushed by the flange portion 10a and becomes deformed.

Since such a second protrusion 6d can be deformed, it is possible to absorb variations in the height position of the flange portion 10a, in other words, variations in the insertion depth of the fuel injection valve 10.

Since the flange portion 10a is located above the injector holder 5, that is, the first gasket 6, the second protrusion 6d comes into contact with the flange portion 10a from below. The second protrusion 6d projecting upward comes into contact with the flange portion 10a pressed toward the second protrusion 6d by the clamp spring 11 from below, so that the flange portion 10a and the second protrusion 6d come into close contact with each other. The property is improved and the sealing property is improved. As a result, water, dust, and the like are prevented from entering the insertion hole 5a. As a result, water and dust are prevented from entering the inside of the injector tube 2.

The second protrusion 6d may have a shape that can secure these functions, and may be, for example, an inwardly wound shape that faces the inside of the ring.

Referring to FIG. 2, a cylinder head cover 12 is provided on the upper side of the injector holder 5. A second gasket 13 is provided between the cylinder head cover 12 and the injector holder 5 and between the cylinder head cover 12 and the cam cap 4. As a result, the cam cap 4 in which the valve train is arranged and the cylinder head 1 are sealed.

The cylinder head cover 12 is provided with a shielding portion 12a that regulates the incident angle of the water flow directed at the first gasket 6 adjacent to the flange portion 10a with which the second protrusion 6d abuts. The shielding portion 12a in the present embodiment is formed in a wall shape.

Here, referring to FIG. 2, the shielding portion 12a is provided on the front end side of the vehicle when the right side and the vehicle interior side in FIG. 2 are set and the left side is the front end side of the vehicle. This is, for example, a measure taken on the assumption that the vehicle body is washed by a high-pressure water stream, especially the engine room. With reference to FIG. 3, arrow 20 represents the angle of incidence of the water stream. The shielding portion 12a is provided so that the water flow discharged from the front upper side of the vehicle does not directly hit the second protrusion 6d. If a high-pressure water stream is directly applied to the second protrusion 6d, the second protrusion 6d may be deformed and water may enter between the second protrusion 6d and the flange portion 10a.

On the other hand, by providing the shielding portion 12a as in the present embodiment, the incident angle of the water flow is regulated. Therefore, even if the water flow enters the lower side of the cylinder head cover 12 from between the cylinder head cover 12 and the flange portion 10a, the water flow does not directly hit the second protrusion 6d.

Although the shielding portion of the present embodiment is provided on the cylinder head cover, it may be provided on other components arranged in the engine room. For example, the injector holder 5 may be provided with a shielding portion. Moreover, the shape can be changed in various ways. An example of modification of the shape of the shielding portion will be described below.

<Modification example 1>
Referring to FIG. 5, the shielding portion 22a of the first modification is common to the shielding portion 12a of the embodiment in that it is provided on the cylinder head cover 22, but its shape is different. The shielding portion 22a is formed in the shape of an eave. By providing the shielding portion 22a, the water flow shown by arrow 23 in FIG. 5 hits the shielding portion 22a and therefore cannot reach the first gasket. Further, in FIG. 5, the water flow indicated by arrow 24 does not directly hit the second protrusion 6d because the angle of incidence thereof is regulated. By changing the distance S between the cylinder head cover 22 and the flange portion 10a, the range of limitation of the incident angle of the water flow can be widened. The narrower the interval S, the more difficult it is for the water flow to reach the second protrusion 6d.

<Modification 2>
Next, a modification 2 will be described with reference to FIG. In the shielding portion 32a of the modified example 2, the plate thickness of the cylinder head cover 32 is thicker than that of the cylinder head cover 22 as compared with the modified example 2. At the same time, the thickness t of the flange portion 10b is also made thicker than the thickness of the flange portion 10a.

By increasing the thickness of the cylinder head cover and the flange portion in this way, it is possible to tighten the limitation of the incident angle of the water flow and make it difficult for the water flow to reach the second protrusion 6d. For example, by increasing the thickness t of the flange portion 10b, it is possible to prevent the water flow from reaching the first gasket 6 as shown by arrow 33 in FIG.

By providing the shielding portion in this way, for example, when cleaning the engine room with a high-pressure water flow, it is possible to prevent the water flow from entering the first gasket 6.

The above-described embodiment is merely an example for carrying out the present invention, the present invention is not limited thereto, and various modifications of these examples are within the scope of the present invention, and further, the present invention It is self-evident from the above description that various other embodiments are possible within the scope.

1 Cylinder head 1a Combustion chamber 2 Injector tube 3 Spark plug tube 4 Cam cap 5 Injector holder 5a Insertion hole 6 1st gasket 6a Flange part 6b Cylindrical part 6c 1st protrusion 6d 2nd protrusion 7 Bolt 8 High pressure delivery 10 Fuel Injection valve 10a, 10b Flange part 11 Clamp spring 12 Cylinder head cover 12a, 22a, 32a Shielding part

Claims (2)

An injector tube into which the fuel injection valve is inserted so that the tip of the fuel injection valve is exposed to the combustion chamber while being mounted on a cylinder head having a combustion chamber formed in the lower part.
An injector holder fixed to the cylinder head and supporting the fuel injection valve,
It has an annular gasket that is attached to the insertion hole provided in the injector holder and is provided between the injector tube and the injector holder.
The gasket has a first protrusion that projects toward the inside of the annular shape and presses the outer peripheral wall surface of the injector tube, and a flange portion that projects upward and is provided above the injector holder of the fuel injection valve. A seal structure of an internal combustion engine having a second protrusion that comes into contact with the fuel from below. The seal structure for an internal combustion engine according to claim 1, further comprising a shielding portion which is provided adjacent to the flange portion with which the second protrusion abuts and regulates an incident angle of a water flow directed at the gasket.

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