JPH11303677A - Cylinder head cover structure in dohc type internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent water from ingressing in an ignition coil in the inside of a cylinder head cover by the time that water accumulated in a part in the inside of a trough crosses one swelled part, and flows out of a groove part. SOLUTION: In this structure, a pipe body 19 communicated with an ignition plug insertion hole 27 the inner part of which is opened to the upper surface of a cylinder head 4, is integrally provided for the inside of the trough 18 of a cylinder head cover 19 in such a way that the lower end face of the pipe body 19 is mounted to the cylinder head 4 of the cylinder head cover 9, and simultaneously, the pipe body is closely in contact with the upper face 4a of the cylinder head 4 so as to allow an upper end 19 to be projected out of the inner bottom surface of the trough 18. An ignition coil 20 is mounted to the upper end of the pipe body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a so-called DOHC type internal combustion engine having a camshaft for an intake valve and a camshaft for an exhaust valve arranged on the upper surface of a cylinder head in parallel.
The present invention relates to a structure of a cylinder head cover mounted on the upper surface of the cylinder head so as to cover the two cam shafts.

[0002]

2. Description of the Related Art In general, in a DOHC type internal combustion engine of this type, an upwardly protruding bulging portion is provided at a portion of the cylinder head cover substantially directly above both cam shafts on the right and left sides thereof. The expansion portion is integrally provided so as to extend in the axial direction of the camshaft, and the inside of the both expansion portions is formed as a gas-liquid separation chamber for extracting blow-by gas in the cylinder head cover, while the cylinder head cover is formed. An ignition coil is provided for each cylinder in a valley portion between the inflated portions on the upper surface of the cylinder.

[0003] However, with this configuration, although the ignition coil for each cylinder can be reliably protected by the inflated portions on both sides of the cylinder, when the cylinder head cover is covered with water, the inflated coils are inflated. Water will accumulate in the valleys between the ridges. Therefore, Japanese Patent Application Laid-Open No. H8-31455 as a prior art discloses that, in the above-described configuration, at least one of the two bulging portions is provided with a bulge from the valley between the two bulging portions. It has been proposed to provide a groove that opens to the side surface of the cylinder head cover across the portion, so that water accumulated in the valley portion flows out of the groove sequentially.

[0004]

However, in this prior art, an upwardly extending pipe body is fixed to an ignition plug mounting hole opened on the upper surface of a cylinder head, and the upper end of the pipe body is attached to the cylinder head cover. And the upper end is provided with the ignition coil so that the pipe body penetrates through the cylinder head cover until the water that has entered the valley flows out of the groove. In addition to the problem that there is a great risk of intrusion into the valve mechanism chamber inside the pipe body and outside the pipe body, that is, into the cylinder head cover, fixing the pipe body to the spark plug on the cylinder head side is only that much. There is also a problem that the number of parts and the number of assembly steps increase.

An object of the present invention is to provide a structure of a cylinder head cover that solves these problems.

[0006]

SUMMARY OF THE INVENTION In order to achieve this technical object, the present invention provides a method of manufacturing a cylinder head cover which is mounted on an upper surface of a cylinder head so as to cover a cam shaft for an intake valve and a cam shaft for an exhaust valve. An upwardly protruding bulge portion is provided substantially directly above the two camshafts, and the bulge portions are integrally provided so that the two bulge portions extend in the axial direction of the two camshafts.
In addition, an ignition coil for each cylinder is provided in a valley between the inflated portions on the upper surface of the cylinder head cover, and at least one of the inflated portions has the In a DOHC type internal combustion engine having a groove that opens to the side surface of a cylinder head cover from a valley between both bulging portions and across the one bulging portion, a position of each cylinder in a valley in the cylinder head cover. A pipe body whose inside communicates with an ignition plug insertion hole that opens on the top surface of the cylinder head, the lower end surface of the pipe body is in close contact with the upper surface of the cylinder head at the same time when the cylinder head cover is attached to the cylinder head, and the upper end is Provided integrally so as to protrude from the inner bottom surface in the valley,
The ignition coil is mounted on the upper end of the pipe body. "
It was configured to say.

[0007]

As described above, the pipe body for attaching the ignition coil to the valley between the two bulging portions is integrated with the cylinder head cover. It is possible to eliminate the possibility of water entering the valve mechanism chamber in the cylinder head cover from a portion penetrating the cylinder head cover, and
The number of parts can be reduced.

The upper end of the pipe protrudes from the inner bottom surface in the valley, and the ignition coil is attached to the upper end, so that the water accumulated in the bottom of the valley flows out of the groove. In the meantime, it is possible to reliably prevent the pipe from flowing into the pipe body from the upper end and from entering the inside of the ignition coil through the air vent hole.

Therefore, according to the present invention, in a DOHC-type internal combustion engine, current leak occurs due to intrusion of water into the ignition coil and ignition plug of each cylinder on the upper surface of the cylinder head cover, Water can be reliably prevented from entering the valve mechanism chamber, and the number of parts and the number of assembly steps can be reduced by integrating the pipe body for the ignition plug with the cylinder head cover.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. In this figure, reference numeral 1 denotes an internal combustion engine in which a cylinder head 4 is fastened to an upper surface of a cylinder block 3 having four cylinders 2. On an upper surface 4a of a cylinder head 4 in the internal combustion engine 1, a cam shaft 5 for an intake valve and a cam shaft 6 for an exhaust valve in each cylinder 2 are supported in parallel in a row. The cylinder head cover 9 made of synthetic resin that covers the entirety of the camshafts 5 and 6 and the power transmission wheels 7 and 8 such as timing pulleys at one end of the camshafts 5 and 6 is provided with a plurality of bolts 10 disposed around the cylinder head cover 9. It is attached detachably. A gasket 11 for sealing is interposed between the lower surface 9a around the cylinder head cover 9 and the upper surface 4a of the cylinder head 4.

At the position of each cylinder 2 in the cylinder head 4, an ignition plug insertion hole 27 for attaching and detaching an ignition plug 26 to and from each cylinder 2 is provided so as to open on the upper surface 4 a of the cylinder head 4. . Further, at least one of the two bulging portions 12 and 13 on the upper surface of the cylinder head cover 9 has a double bulging portion 1.
The groove 24 that opens from the portion inside the valley 18 between the ridges 2 and 13 to the side surface of the cylinder head cover 9 across the one bulging portion 12 is formed as the inner bottom surface 24 a of the groove 24. 18a so as to extend in the same plane.

In the ceiling plate of the cylinder head cover 9, bulging portions 12, 13 protruding upward are provided on portions of the ceiling plate directly above the two cam shafts 5, 6 in the axial direction of the two cam shafts 5, 6. The two bulging portions 1 are integrally provided so as to extend
The insides of the components 2 and 13 are formed in gas-liquid separation chambers 16 and 17 partitioned by bottom plates 14 and 15. And, on the upper surface of the cylinder head cover 9, the two bulging portions 12,
13, a portion inside the valley 18 is provided with the spark plug insertion hole 2.
7 is provided integrally with each cylinder at two locations, and the lower end surface 19a of each pipe body 19 is made substantially flush with the lower surface 9a around the cylinder head cover 9, or The cylinder head cover 9 is configured to protrude by a dimension S smaller than the surrounding lower surface 9a, so that the cylinder head cover 9 comes into close contact with the upper surface 4a of the cylinder head 4 at the same time as the cylinder head cover 9 is attached to the cylinder head 4. On the other hand, the upper end 19b of the pipe body 19 protrudes from the inner bottom surface 18a of the valley 18 by an appropriate dimension H, and the ignition coil 20 for the ignition plug 26 in each cylinder 2 is mounted on the upper end 19b. .

The lower end surface 19a of each pipe body 19 in the cylinder head cover 9 and the cylinder head 4
A ring-shaped gasket 28 is inserted between the gasket 28 and the upper surface 4a so as to surround the periphery of the ignition plug insertion hole 27. Also, on the upper surface of one of the bulging portions 13 of the two bulging portions 12 and 13 on the upper surface of the cylinder head cover 9, an electric wiring 21 for each of the ignition coils 20,
Various electric wiring such as an electric wiring 22 from a timing sensor (not shown) for detecting the phase of the crank angle is provided below the internal combustion engine 1. In addition, these various electric wirings 21 and 22 are engaged by a locking piece 23 provided on one of the bulging portions 13 constantly.
The one electric wiring 22 is wired so as to extend downward through the inside of the groove 24 after being fixed to the inner bottom surface 24 a of the groove 24 by the locking piece 25.

As described above, the pipe body 19 for attaching the ignition coil 20 to the valley 18 between the two bulging portions 12 and 13 is integrated with the cylinder head cover 9 so that the pipe body 19 is formed in a conventional manner. From the portion where the pipe penetrates the cylinder head cover, the cylinder head cover 9
It is possible to eliminate the possibility that water will enter the valve operating mechanism chamber and reduce the number of parts.

The upper end 19b of the pipe body 19 is
By protruding from the inner bottom surface 18a of the valley 18 by an appropriate dimension H and attaching the ignition coil 20 to the upper end 19b, the water accumulated on the inner bottom surface 18a of the valley 18 is discharged until the water flows out of the groove 24. In between,
It is possible to reliably prevent the pipe body 19 from flowing into the ignition coil 20 from the upper end 19b and the inside of the ignition coil 20 from the air vent hole.

When the cylinder head cover 9 is made of synthetic resin, the periphery of the cylinder head cover 9 is fastened to the cylinder head 4 with bolts 10 and the center of the cylinder head cover 9 is If the lower end surface 19a of each pipe body 19 provided integrally with the portion is configured so that the lower surface 9a around the cylinder head cover 9 is substantially flush, the pressing force of each pipe body 19 against the cylinder head 4 is reduced. As a result, the sealing performance between the lower surface 19a of each pipe body 19 and the upper surface 4a of the cylinder head 4 is reduced.

Therefore, in the present invention, as shown in FIG. 5, the lower end surface 19a of each of the pipe bodies 19 is configured to protrude by a dimension S smaller than the surrounding lower surface 9a of the cylinder head cover 9. Accordingly, the pressing force of the pipe bodies 19 against the cylinder head 4 can be increased, so that the pipe bodies 1
The sealability between the lower surface 19a of the cylinder 9 and the upper surface 4a of the cylinder head 4 can be improved.

The sealing performance of each pipe member 19 with respect to the cylinder head 4 is such that a boss portion 29 is integrally provided at a portion between the pipe members 19 and
The structure can be further improved by fastening the upper surface of the cylinder head 4 with the bolt 30. The lower end surface 29a of the boss portion 29 is also configured to protrude by a dimension S smaller than the surrounding lower surface 9a of the cylinder head cover 9, and the lower end surface 2a
A ring-shaped gasket 31 for sealing is also mounted on 9a.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along line III-III of FIG.

FIG. 4 is a sectional view taken along line IV-IV of FIG.

FIG. 5 is a vertical sectional front view of a cylinder head cover.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Cylinder 3 Cylinder block 4 Cylinder head 5, 6 Camshaft 9 Cylinder head cover 12, 13 Inflated part 18 Valley 18a Valley bottom 19 Pipe 19a Lower end of pipe 19b Upper end of pipe 20 Ignition coil 24 Groove 26 Spark plug 27 Spark plug insertion hole

Claims (1)

[Claims] 1. A cylinder head cover mounted on an upper surface of a cylinder head so as to cover an intake valve camshaft and an exhaust valve camshaft, and protrudes upward from a ceiling plate substantially directly above the two camshafts. The inflated portion is provided integrally so that the two inflated portions extend in the axial direction of both camshafts, and
On the upper surface of the cylinder head cover, an ignition coil for each cylinder is provided in a valley between the inflated portions, and at least one of the inflated portions is provided with the inflated portion. In a DOHC type internal combustion engine having a groove that opens from the valley between the bulge portions to the side surface of the cylinder head cover across the one bulge portion, at a position of each cylinder in the valley of the cylinder head cover, A pipe body whose inside communicates with an ignition plug insertion hole that opens on the upper surface of the cylinder head, the lower end surface of the pipe body is in close contact with the upper surface of the cylinder head at the same time when the cylinder head cover is attached to the cylinder head, and the upper end is in the valley. Wherein the ignition coil is attached to an upper end of the pipe body so as to protrude from the inner bottom surface. Structure of cylinder head cover in a fuel engine.