JP6713707B2 - Internal combustion engine - Google Patents

Description

The present invention relates to an internal combustion engine capable of hydraulically controlling the opening/closing timing of an intake valve or an exhaust valve.

In an internal combustion engine for a vehicle or the like, the opening/closing timing of either or both of an intake valve and an exhaust valve is controlled. As one of the valve timing control methods, the camshaft is advanced or retarded with respect to the chain sprocket. Lubricating oil is used as the camshaft control method. There are known a hydraulic VVT method that is controlled by hydraulic pressure and an electric VVT that is controlled by an electric motor. Patent Document 1 discloses an example of the hydraulic VVT method.

JP-A-2000-199417

As described above, when controlling the camshaft to adjust the valve timing, the drive source is divided into hydraulic type and electric type, and when viewed from the controlled object, only the intake valve camshaft is controlled. It is divided into a case, a case where both the intake valve camshaft and the exhaust valve camshaft are controlled, and a case where only the exhaust valve camshaft is controlled.

The internal combustion engine has a method of controlling only the intake valve camshaft or a method of controlling both the intake valve camshaft and the exhaust valve camshaft, depending on the target performance such as fuel consumption and output. However, the structure of the cylinder head and cam cap was changed. Therefore, a cylinder head manufacturing line is configured for each internal combustion engine having a different camshaft rotation control method. Therefore, if the number of types of internal combustion engine is increased, the manufacturing cost and the management cost increase proportionally. was there.

The present invention aims to remedy this problem.

The present invention is
"An intake valve camshaft and an exhaust valve camshaft driven via a chain sprocket, and an end cam for rotatably holding a portion near one end of the intake valve camshaft and the exhaust valve camshaft on a cylinder head. A cap and a head cover fixed to the cylinder head and covering the both cam shafts and the end cam caps,
An oil passage with a built-in head for controlling valve timing by hydraulically rotating the cam shaft relative to the chain sprocket at a position near one cam shaft of the cylinder head and overlapping with the end cam cap. While the open
A bridge-shaped oil passage for controlling relative rotation of the other cam shaft with respect to the chain sprocket is provided in the end cam cap so as to communicate with the head built-in oil passage .
It has a basic configuration.

And in the above basic configuration,
“The bridge-shaped oil passage communicates with the head built-in oil passage and extends to a position higher than the camshaft, and a first portion communicates with an upper end of the first portion and extends toward the other camshaft. It is composed of two parts and a third part that communicates with the second part and faces the cylinder head, and the second part is pressed and held by the head cover in a state of overlapping the end cam cap from above. It is formed by a pipe-shaped member,
The upward projection received on the pipe-shaped member and the downward projection provided on the head cover are brought into contact with each other, or a positioning projection provided on one of the pipe-shaped member and the head cover is provided in a positioning hole provided on the other. They are fitted together"
Is added.

In the present invention, the control mode of the camshaft includes a case where only advance control is performed, a case where only retard control is performed, and a case where both advance control and retard control are performed.

In the present invention, in the case where one of the intake valve camshaft and the exhaust valve camshaft is hydraulically advanced or retarded, the end camcap having the bridge-shaped oil passage is used. Instead, an end cam cap having a hydraulic passage communicating with a control device provided at one end of one cam shaft may be used.

On the other hand, the intake valve camshaft is controlled by the electric VVT, the exhaust valve camshaft is controlled by the hydraulic VVT, and one camshaft is controlled by the electric VVT, and the other camshaft is controlled by the hydraulic VVT. Although there is a method of controlling by the formula VVT, in this case, by using the end cam cap of the present invention, the other cam shaft can be controlled by the hydraulic VVT without changing the structure of the cylinder head. it can.

Further, even when one camshaft is not controlled and only the other camshaft is controlled by the hydraulic VVT, the end cam cap of the present invention may be attached. When controlling both the intake valve camshaft and the exhaust valve camshaft with an electric VVT, use an end cam cap that closes the outlet of the head built-in oil passage, and use an oil control valve (OCV). You can remove it.

As described above, according to the present invention, since the camshaft controlled by the hydraulic pressure can be selectively switched by simply changing the end cam cap without changing the structure of the cylinder head, a plurality of different valve timing methods can be used. The cylinder head can be made common when assorting various types of internal combustion engines. This makes it possible to suppress the manufacturing cost and management cost of the cylinder head when preparing a plurality of types of internal combustion engines having different valve timing control modes.

In particular, when changing to a specification in which only the intake valve camshaft is controlled by a hydraulic VVT, and a specification in which the intake valve camshaft is controlled by an electric VVT and the exhaust valve camshaft is controlled by a hydraulic VVT. Be beneficial. It should be noted that the invention of the present application can be adapted to the change of the valve timing control system of the existing internal combustion engine, which is also an advantage of the invention of the present application.

If the pipe-shaped member is added to form the bridge-shaped oil passage as in the present invention, the freedom of design of the end cam cap can be improved.

It is a perspective view of the implementation forms. It is a plan view of the implementation forms. A separation plan view of implementation forms. A separation front view of implementation forms. It is a figure which shows the end cam cap of embodiment, (A) is a top view, (B) is a front view, (C) is a bottom view.

Next, an embodiment of the present invention will be described with reference to the drawings. In the following embodiments, the wording "front and rear" and "right and left" is used to specify the direction. The left-right direction is a direction orthogonal to the cylinder bore when viewed from the crank axis direction. As a precaution, the direction is clearly shown in FIG.

(1). Summary of the implementation forms
In this embodiment, the basic configuration of the internal combustion engine is the same as that of the conventional one. For example, as can be understood most easily from FIG. 4, the internal combustion engine includes the cylinder head 1, the intake valve camshaft 2, and the exhaust valve camshaft 3. The camshafts 2 and 3 are rotatably held by front cam caps (end cam caps) 4 at the front end parts (end part ends) of both cam shafts 2, 3. The front cam cap 4 is, for example, an aluminum die cast product or a cast product.

In the present embodiment, a part of the bridge-shaped oil passage is configured by the pipe-shaped member 5, and the left and right end portions 5 a of the pipe-shaped member 5 are overlapped with the left and right end portions of the front cam cap 4 via the gasket 6. There is. The valve operating chamber is covered by the head cover 7, but the pipe-shaped member 5 is held by the head cover 7 by the front cam cap 4. Needless to say, the peripheral portion of the head cover 7 is fixed to the outer peripheral portion of the cylinder head 1 with bolts.

As shown in FIGS. 2 and 3, the cylinder head 1 includes front bearing portions 8a and 8b into which the lower half portions of the front end portions of the cam shafts 2 and 3 are fitted, and the lower middle portions of the cam shafts 2 and 3. An intermediate bearing portion 9 into which the half portion is fitted and a rear bearing portion (not shown) into which the lower half portion of the rear end portion of the camshafts 2 and 3 are fitted are formed, and the front cam cap 4 and other not-shown parts are formed. The cam cap is formed with recesses 10a and 10b having downward openings which cover the upper half portions of the cam shafts 2 and 3. In FIG. 2, the cam formed on both cam shafts 2 and 3 is indicated by reference numeral 11.

A spark plug mounting hole 12 is formed in the cylinder head 1 at a position corresponding to the intermediate bearing portion 9, and two front and rear valve disposing holes 13 are opened on both left and right sides sandwiching the spark plug mounting hole 12. doing. The front cam cap 4 is arranged on the upper surface of the front end portion of the cylinder head 1, and is fixed to the cylinder head 1 by four bolts 14 (see FIG. 1) arranged in the left-right direction. In FIG. 3, reference numeral 15 indicates a screw hole for fixing the front cam cap 4.

Chain sprockets 16 and 17 are attached to the front ends of the camshafts 2 and 3 via an electric VVT gear 16a and a hydraulic VVT 17a, and a timing chain 18 is wound around both chain sprockets 16 and 17. ..

As schematically shown in FIG. 2, an electric VVT gear 16a is arranged in front of the intake side chain sprocket 16, and a hydraulic VVT 17a is arranged in front of the exhaust side chain sprocket 17. It is covered with the front cover 19. The electric VVT gear 16 a is driven by an electric motor (not shown), but the electric motor is arranged on the front surface of the front cover 19, and therefore the rotation shaft of the electric motor penetrates the front cover 19.

On the other hand, the rotation control device for the exhaust valve camshaft 3 adopts a hydraulic type, and the opening/closing timing of the exhaust valve can be advanced or retarded from the reference state by adjusting the pressure feeding timing of the lubricating oil. Can be controlled.

(2). Hydraulic Path As shown in FIGS. The outlet is open. The head built-in oil passages 21 and 22 are opened to the front surface of the cylinder head 1, and an oil control valve (OCV) 23 with a filter is arranged on the front surface of the cylinder head 1. By controlling the pressure feed of oil by the oil control valve 23, the exhaust valve camshaft 3 can be advanced or retarded. Although there are two head built-in oil passages 21, one is an advance passage and the other is a retard passage.

As clearly shown in FIG. 5, the front cam cap 4 has a large front-rear width at the recesses 10a and 10b, and four mounting holes 24 are arranged in the left-right direction so that the four bolts 14 can be fitted therein. Is formed by. In FIG. 5(B), an inward rib 25 is provided in the intake side recess 10 a, but this is for preventing the intake valve camshaft 2 from shifting in the front-rear direction.

As shown in FIG. 5C, arcuate grooves 26 are formed in the left and right recesses 10a and 10b of the front cam cap 4 to lubricate the camshafts 2 and 3, and the left and right arcuate grooves 26 are It is gathered in one intermediate concave portion 28 via the communication passage 27. As shown in FIG. 3, a lubricating oil feed hole 29 that overlaps with the intermediate recess 28 of the front cam cap 4 is formed in a portion of the cylinder head 1 between the left and right front bearing portions 8a and 8b.

Therefore, the lubricating oil is supplied to the front bearing portions 8a and 8b from the lubricating oil feeding hole 29, but the camshafts 2 and 3 are communicated with the annular groove communicating with the arcuate groove 26 and the annular groove. And a distribution passage formed so as to extend long in the axial center portion in the state. Lubricating oil is supplied from the location of the front bearing portions 8a, 8b to the distribution passage via the arcuate groove 26, and each intermediate It is supplied to the bearing portion and the rear bearing portion. The oil used for lubrication in each bearing part flows down into the valve operating chamber. At the front bearings 8a and 8b, the front and rear ends leak to the valve operating chamber and the like.

A bridge-shaped oil communicating with the head built-in oil passages 21 and 22 is provided on the upper surface of the first land portion 30 by projecting upward the first land portion 30 at the intake side recess 10a of the front cam cap 4. The passage first portions 31 and 32 are open.

On the other hand, a second land portion 33 is provided so as to project upward at the location of the exhaust side recess 10b of the front cam cap 4, and the drill holes 34a and 34b of the upward opening formed in the second land portion 33 and the side surface are formed. By the oblique drill holes 35a and 35b in the inclined posture, bridge-shaped oil passage third portions 36 and 37 (see FIG. 5C) opened in the recesses 10a and 10b are formed. The second land portion 33 is formed with a rearward projecting portion 38 for forming the diagonal drill holes 35a and 35b, and the upper ends of the diagonal drill holes 35a and 35b are closed by plugs.

The two bridge-shaped oil passage third portions 36, 37 are open in the recess 10b so as to be separated from each other in the front-rear direction, and through the oil passage formed in the exhaust valve camshaft 3 to the oil inlet of the hydraulic VVT 17a. It communicates with the oil outlet. The left and right end portions of the pipe-shaped member 5 are overlapped with the two lands 30 and 33 of the front cam cap 4 with the gasket 6 interposed therebetween, and the bridge-shaped oil passage second provided in the pipe-shaped member 5 is provided. The portions 39, 40 communicate with the bridge-shaped oil passage third portions 36, 37 via the bridge-shaped oil passage first portions 31, 32 and the drill holes 34a, 34b, 35a, 35b. The bridge-shaped oil passage third portions 39, 40 are composed of a horizontal portion and downward opening portions connected to the left and right ends thereof.

For example, as shown in FIG. 4, upward protrusions 41 are formed on the left and right end portions 5a of the pipe-shaped member 5, and downward protrusions 42 formed on the head cover 7 come into contact with the upward protrusions 41 of the front cam cap 4. There is. Although a gasket 6 is present between the pipe-shaped member 5 and the front cam cap 4, the gasket 6 is fitted into a gasket groove formed in one of the pipe-shaped member 5 and the front cam cap 4. Therefore, the proper sealing property is maintained. For this reason, the sealing property is secured even by just pressing with the head cover 7, and the land portions 30, 33 and the end portion 5a of the pipe-shaped member 5 are connected with a pin or fastened with a bolt. Thereby, the pipe-shaped member 5 is held so as not to be displaced.

It is also possible to form a positioning projection on one of the pipe-shaped member 5 and the head cover 7 and a positioning recess on the other so that the projection and the recess are fitted together. Alternatively, the pipe member 5 may be formed of a steel pipe or an aluminum pipe, and the end portion thereof may be forcibly fitted to the front cam cap 4.

(3). Or stop <br/> cylinder head 1 of this embodiment, originally is designed for controlling the intake valve camshaft 2 with hydraulic VVT. Therefore, when the intake valve camshaft 2 is hydraulically controlled, a front cam cap having an oil passage for controlling the intake valve camshaft 2 is used.

On the other hand, when the front cam cap 4 of the present embodiment is used, as described above, the intake valve camshaft 2 is controlled in advance/retard by the electric VVT, and the exhaust valve camshaft 3 is The oil sent via the head built-in oil passage 21 and the bridge-shaped oil passages 31, 32, 39, 40, 36, 37 is advanced by the hydraulic VVT 17a provided at the front end of the exhaust valve camshaft 3. Or retarded or controlled.

Therefore, a) an internal combustion engine used for controlling the opening/closing timing of the intake valve with the hydraulic VVT 17a and not controlling the opening/closing timing of the exhaust valve, b) controlling the opening/closing timing of the intake valve with the electric VVT (16a), the internal combustion engine of type opening and closing timing of the exhaust valve is controlled by hydraulic VVT17a, c) opening and closing timing of the intake valve is controlled by hydraulic VVT17a, opening and closing timing of the exhaust valve of the type controlled by electric VVT (16a) Two types of cylinder heads 1 can be shared by three types of internal combustion engines. Therefore, it is possible to suppress the manufacturing cost and the management cost of the cylinder head 1 while enriching the product lineup of the internal combustion engine and responding to the fine request of the user.

The present invention can be embodied in various ways other than the above embodiment . For example, the arrangement position of the oil filter and the arrangement position of the oil control valve can be set arbitrarily. The head built-in oil passage may be provided near the exhaust valve cam shaft (or the exhaust side bearing portion). ).

1 Cylinder head 2 Intake valve camshaft (one camshaft)
3 Exhaust valve camshaft (other camshaft)
4 Front cam cap (end cam cap)
5 Pipe-shaped member 6 Gasket 8a, 8b Front bearing part 10a, 10b Recess of front cam cap 16,17 Chain sprocket 16a Electric VVT gear 17a Hydraulic VVT
18 Timing chain 10 Front cover 21 Head built-in oil passage 23 Oil control valve (OCV)
31, 32, 39, 40, 36, 37 Bridge-shaped oil passage
41 Upward protrusion provided on the pipe-shaped member
42 downward projections 44, 45, 46, 47, 48, 50 provided on the head cover bridge-shaped oil passage

Claims (1)

An intake valve camshaft and an exhaust valve camshaft driven via a chain sprocket, and an end cam cap for rotatably holding a portion of the intake valve camshaft and the exhaust valve camshaft near one end on a cylinder head. And a head cover fixed to the cylinder head to cover the both cam shafts and the end cam caps,
An oil passage with a built-in head for controlling valve timing by hydraulically rotating the cam shaft relative to the chain sprocket at a position near one cam shaft of the cylinder head and overlapping with the end cam cap. While the open
A bridge-shaped oil passage for controlling relative rotation of the other cam shaft with respect to the chain sprocket is provided in the end cam cap so as to communicate with the head built-in oil passage ,
The bridge-shaped oil passage communicates with the head built-in oil passage and extends to a position higher than the camshaft, and a second portion communicates with an upper end of the first portion and extends toward the other camshaft. And a third portion communicating with the second portion toward the cylinder head, the second portion being pressed and held by the head cover so as to overlap with the end cam cap from above. It is formed by a pipe-shaped member,
The upward projection received on the pipe-shaped member and the downward projection provided on the head cover are brought into contact with each other, or a positioning projection provided on one of the pipe-shaped member and the head cover is provided in a positioning hole provided on the other. Fit together,
Internal combustion engine.

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