JP2018017221A - Internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cut down on costs by making a cylinder head common in use when manufacturing a plurality of kinds of internal combustion engines which are different from one another in valve timing adjustment systems.SOLUTION: Head-incorporated oil passages 21, 22 are opened at the outside of an intake-side receiving part 8a out of a front end part of a cylinder head 1. When an intake valve cam shaft 2 is controlled by a hydraulic VVT, a front cam cap having a control oil passage in a region overlapped on the intake valve cam shaft 2 is used. The intake valve cam shaft 2 is controlled by an electric VVT, and when an exhaust valve cam shaft 3 is controlled by the hydraulic VVT, a front cam cap 4 in which oil is sent to an exhaust side from an intake side by bridge-shaped oil passages 31, 32, 39, 40, 36 and 37 is used. One kind of the cylinder head 1 can be used in common in a plurality of kinds of internal combustion engines which are different in valve timing adjustment systems.SELECTED DRAWING: Figure 3

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 one 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 system that is controlled by hydraulic pressure and an electric VVT that is controlled by an electric motor. An example of a hydraulic VVT system is disclosed in Patent Document 1.

JP 2000-199417 A

  As described above, when adjusting the valve timing by controlling the camshaft, it is divided into a hydraulic type and an electric type when viewed from the drive source, and only the intake valve camshaft is controlled when viewed from the control target. The case is divided into 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 for controlling only the intake valve camshaft and a method for controlling both the intake valve camshaft and the exhaust valve camshaft according to target performance such as fuel consumption and output. If they are different, the structure of the cylinder head and cam cap has been changed. Therefore, a cylinder head production line is configured for each internal combustion engine with a different camshaft rotation control method. Therefore, when the number of types of internal combustion engines is increased, the production cost and the management cost increase proportionally. was there.

  The present invention aims to remedy this problem.

The present invention is
"A structure near one end of an intake valve camshaft and an exhaust valve camshaft driven via a chain sprocket is rotatably held by a cylinder head by an end cam cap,
An oil passage with a built-in head for controlling the valve timing by rotating the cam shaft relative to the chain sprocket by hydraulic pressure in the vicinity of one cam shaft of the cylinder head and overlapping with the end cam cap. While is open
The end cam cap is provided with a bridge-like oil passage for controlling the relative rotation of the other camshaft with respect to the chain sprocket so as to communicate with the head built-in oil passage.
It is the composition.

  In the present invention, the bridge-shaped oil passage may be formed as a groove or a hole in the end cam cap itself, or may be formed by adding another pipe-shaped member. In the case of adding a pipe-like separate member, the separate member can be fixed to the end cam cap with a screw or the like, or can be pressed and held by the head cover as shown in the embodiment.

  The head built-in oil passage outlet may be located on the outside of the camshaft or on the inside sandwiched between the intake valve camshaft and the exhaust valve camshaft. When the outlet of the built-in oil passage is located outside the camshaft, the bridge-like oil passage extends over the intake valve camshaft and the exhaust valve camshaft. Is located on the inner side between the intake valve camshaft and the exhaust valve camshaft, the bridge-shaped oil passage should be formed as a groove on the surface of the end camcap that overlaps the cylinder head. Can do.

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

  In the present invention, when one of the intake valve cam shaft and the exhaust valve cam shaft is hydraulically advanced or retarded, the end cam cap having a 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 camshaft may be used.

  On the other hand, the camshaft for intake valve is controlled by electric VVT, the camshaft for exhaust valve is controlled by hydraulic VVT, and the other camshaft is hydraulically controlled by electric VVT. In this case, by using the end cam cap of the present invention, the other camshaft can be controlled by the hydraulic VVT without changing the structure of the cylinder head. it can.

  Also, the end cam cap of the present invention may be mounted even when only one camshaft is controlled by a hydraulic VVT without controlling one camshaft. When both the intake valve camshaft and the exhaust valve camshaft are controlled by electric VVT, an end cam cap that closes the outlet of the head built-in oil passage is used, and the oil control valve (OCV) is Remove it.

  Thus, in the present invention, the camshaft controlled by hydraulic pressure can be selectively switched by simply changing the end cam cap without changing the structure of the cylinder head. A cylinder head can be used in common for assortment of types of internal combustion engines. Thereby, in preparing a plurality of types of internal combustion engines having different valve timing control modes, the manufacturing cost and management cost of the cylinder head can be suppressed.

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

  If the bridge-like oil passage is formed in the end cam cap itself, it is possible to suppress the labor of member management. On the other hand, when a separate member is added to form a bridge-shaped oil passage, the design flexibility of the end cam cap can be improved.

It is a perspective view of a 1st embodiment. It is a top view of a 1st embodiment. It is a separation top view of a 1st embodiment. It is a separation front view of a 1st embodiment. It is a figure which shows the edge part cam cap of 1st Embodiment, (A) is a top view, (B) is a front view, (C) is a bottom view. It is a separation top view of a 2nd embodiment. It is the isolation | separation front view of 2nd Embodiment. It is a figure which shows the edge part cam cap of 2nd Embodiment, (A) is a side view, (B) is a top view, (C) is a front view, (D) is a bottom view.

  Next, an embodiment of the present invention will be described with reference to the drawings. In the following embodiments, front / rear / left / right words are used to specify the direction, but the front / rear direction is the crank axis direction, and the front cover (chain cover) is provided in front. 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). Outline of First Embodiment First, the first embodiment shown in FIGS. 1 to 5 will be described. In this embodiment, the basic configuration of the internal combustion engine is the same as that of the prior art. 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 front-shaft part (one-end part part) of both cam shafts 2 and 3 is rotatably held by a front cam cap (end cam cap) 4. 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 overlap the left and right end portions of the front cam cap 4 via the gasket 6. Yes. The valve operating chamber is covered with a head cover 7, but the pipe-like member 5 is held by the front cam cap 4 by the head cover 7. Needless to say, the head cover 7 is fixed to the outer peripheral portion of the cylinder head 1 with a bolt at the periphery thereof.

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

  A spark plug mounting hole 12 is formed at a position corresponding to the intermediate bearing portion 9 in the cylinder head 1. Two front and rear valve arrangement holes 13 are opened on both the left and right sides of the spark plug mounting hole 12. doing. The front cam cap 4 is disposed 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, a screw hole for fixing the front cam cap 4 is denoted by reference numeral 15.

  Chain sprockets 16 and 17 are attached to the front end portions 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 the chain sprockets 16 and 17. .

  As schematically shown in FIG. 2, an electric VVT gear 16a is disposed in front of the intake-side chain sprocket 16, and a hydraulic VVT 17a is disposed in front of the exhaust-side chain sprocket 17. Covered with a front cover 19. Although the electric VVT gear 16 a is driven by an electric motor (not shown), the electric motor is disposed on the front surface of the front cover 19, and therefore the rotating shaft of the electric motor passes through the front cover 19.

  On the other hand, the rotation control device for the exhaust valve camshaft 3 employs a hydraulic system, and the opening / closing timing of the exhaust valve is advanced or retarded from the reference state by adjusting the pumping timing of the lubricating oil. Can be controlled.

(2). Hydraulic passage As shown in FIGS. 2 and 3, the head built-in oil passages 21 and 22 are provided on the left outer side of the intake valve camshaft 2 (one camshaft) in the front portion of the cylinder head 1. The outlet is open. The head built-in oil passages 21 and 22 are open to the front surface of the cylinder head 1, and an oil control valve (OCV) 23 with a filter is disposed on the front surface of the cylinder head 1. By controlling the oil pumping with the oil control valve 23, the exhaust valve camshaft 3 can be advanced or retarded. 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. It is formed with. In FIG. 5 (B), an inward rib 25 is provided in the intake side recess 10a, and this is to prevent the intake valve camshaft 2 from shifting in the front-rear direction.

  As shown in FIG. 5C, arc-shaped 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 arc-shaped grooves 26 are They are gathered in one intermediate recess 28 via the communication passage 27. As shown in FIG. 3, a lubricating oil feed hole 29 that overlaps 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 8 a and 8 b.

  Accordingly, the lubricating oil is supplied to the front bearing portions 8a and 8b from the lubricating oil feed hole 29, but the camshafts 2 and 3 communicate with the annular groove communicated with the arc-shaped groove 26 and the annular groove. And a distribution passage formed so as to extend long in the shaft center portion in the state. Lubricating oil is supplied from the locations of the front bearing portions 8a and 8b to the distribution passage via the arc-shaped groove 26, and each intermediate passage is provided. Supplied to the bearing portion and the rear bearing portion. The oil used for lubrication in each bearing portion flows down into the valve chamber. At the locations of the front bearing portions 8a and 8b, leakage occurs from the front and rear ends to the valve train chamber and the like.

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

  On the other hand, a second land portion 33 protrudes upward from the front cam cap 4 at the exhaust-side recess 10b, and the upwardly opened drill holes 34a and 34b formed in the second land portion 33 and the side surfaces thereof. The bridge-shaped oil passage third portions 36 and 37 (see FIG. 5C) opened in the recesses 10a and 10b are formed by the oblique drill holes 35a and 35b in the tilted view. The second land portion 33 is formed with a rearward projecting portion 38 for opening oblique drill holes 35a, 35b, and upper ends of the oblique drill holes 35a, 35b are closed with plugs.

  The two bridge-like oil passage third portions 36, 37 are opened in the recess 10b with a front-rear separation, and the oil inlet of the hydraulic VVT 17a is connected to the oil passage Vt 17a through an oil passage formed in the exhaust valve camshaft 3. It communicates with the oil outlet. The left and right end portions of the pipe-like member 5 are overlapped with the two land portions 30 and 33 of the front cam cap 4 via the gasket 6, and the bridge-like oil passage second provided in the pipe-like member 5 is disposed. The portions 39 and 40 communicate with the bridge-like oil passage third portions 36 and 37 via the bridge-like oil passage first portions 31 and 32 and the drill holes 34a, 34b, 35a and 35b. The bridge-like oil passage third portions 39, 40 are composed of a horizontal portion and a downward opening portion connected to the left and right ends thereof.

  For example, as shown in FIG. 4, upward projections 41 are formed on the left and right ends 5 a of the pipe-like member 5, and downward projections 42 formed on the head cover 7 come into contact with the upward projections 41 of the front cam cap 4. Yes. A gasket 6 exists between the pipe-shaped member 5 and the front cam cap 4, but the gasket 6 fits into a gasket groove formed in one of the pipe-shaped member 5 and the front cam cap 4. Therefore, an appropriate sealing property is maintained. For this reason, sealing performance is ensured even if it is only pressed by the head cover 7, and the land portions 30 and 33 and the end portion 5a of the pipe-like member 5 are connected by pins or fastened by bolts. Thus, the pipe-like member 5 is held so as not to be displaced.

  Of the pipe-shaped member 5 and the head cover 7, it is possible to form a positioning projection on one side and a positioning recess on the other side, and fit the projection and the recess. Alternatively, the pipe-like member 5 may be formed of a steel pipe or an aluminum pipe, and the end thereof may be forcibly fitted to the front cam cap 4.

  Further, in the present embodiment, the pipe-like member 5 is overlapped with the front cam cap 4 from above, but the pipe-like member 5 can be overlapped with the front cam cap 4 from the front side or the rear side. In this case, the form of the bridge-like oil passage is also different from the embodiment).

(3). Summary of First Embodiment The cylinder head 1 of the present embodiment is originally designed on the assumption that the intake valve camshaft 2 is controlled by a hydraulic VVT. Therefore, when the intake valve camshaft 2 is controlled hydraulically, 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 advanced and retarded 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-like oil passages 31, 32, 39, 40, 36, 37 is advanced by a hydraulic VVT 17a provided at the front end of the exhaust valve camshaft 3. It is controlled and retarded.

  Therefore, a) the opening / closing timing of the intake valve is controlled by the hydraulic VVT 17a, and the opening / closing timing of the exhaust valve is not controlled, and b) the opening / closing timing of the intake valve is controlled by the electric VVT (16a), Exhaust valve opening / closing timing is controlled by hydraulic VVT 17a, c) Intake valve opening / closing timing is controlled by hydraulic VVT 17a, and exhaust valve opening / closing timing is controlled by electric VVT (16a). Two types of cylinder heads 1 can be shared by three types of internal combustion engines. For this reason, it is possible to suppress the manufacturing cost and management cost of the cylinder head 1 while enriching the product lineup of the internal combustion engine and responding to the detailed requests of the user.

(4). Second Embodiment Next, a second embodiment shown in FIGS. In the second embodiment, a bridge-shaped oil passage is formed integrally with the front cam cap 4, and the cylinder head 1 has the same structure as that of the first embodiment.

  In this embodiment, the bridge-like oil passage communicates with the head built-in oil passage 21 and rises in an inclined posture, and the left and right laterally elongated first and second inclined holes 44, 45 communicated with the inclined holes 44, 45. The first horizontal hole 46 located above the first horizontal hole 46 communicates with the third inclined hole 48 at a location above the exhaust-side recess 10b. The end of the two inclined holes 48 opens to the exhaust-side recess 10b and communicates with the same hydraulic VVT 17a as shown in the first embodiment. The third inclined hole 48 is formed in the protruding ridge portion 49 in an inclined posture, and the upper end of the third inclined hole 48 is closed with a brag. The first and second horizontal holes 46 and 47 are formed by shifting the height and the front-rear position, and the opening is closed with a brag.

  On the other hand, the second horizontal hole 47 having a low height communicates with the fourth inclined hole 50 on the inner side of the intake side recess 10a. The fourth inclined hole 50 opens in a portion of the front cam cap 4 between the left and right recesses 10a and 10b. The lower surface of the front cam cap 4 has a fourth inclined hole 50 and an exhaust side recess 10b. The communication path 51 communicates with the hydraulic VVT at the exhaust side recess 10b.

  Therefore, in this embodiment, the two bridge-shaped oil passages are formed on the inner side and the outer side in a front view, and are directed toward the exhaust side recess 10b in a state of straddling the intake side recess 10a. . In this embodiment, since the bridge-like oil passage is formed integrally with the front cam cap 4 itself, the labor of member management can be suppressed.

  The present invention can be embodied in various ways other than the above-described embodiment. When the bridge-like oil passage is formed integrally with the front cam cap as in the second embodiment, it is possible to form the two bridge-like oil passages substantially in parallel throughout. The arrangement position of the oil filter and the arrangement position of the oil control valve can be arbitrarily set. The head built-in oil passage can be provided in the vicinity of the exhaust valve camshaft (or the exhaust-side bearing portion). ).

1 Cylinder head 2 Intake valve camshaft (one camshaft)
3 Exhaust valve camshaft (the other camshaft)
4 Front cam cap (end cam cap)
5 Pipe-shaped member 6 Gasket 8a, 8b Front bearing 10a, 10b Front cam cap recess 16, 17 Chain sprocket 16a Electric VVT gear 17a Hydraulic VVT
18 Timing chain 10 Front cover
21 Oil passage with built-in head 23 Oil control valve (OCV)
31, 32, 39, 40, 36, 37 Bridged oil passage 44, 45, 46, 47, 48, 50 Bridged oil passage

Claims (1)

A portion near one end of the intake valve camshaft and the exhaust valve camshaft driven via the chain sprocket is rotatably held by the cylinder head by the end cam cap,
An oil passage with a built-in head for controlling the valve timing by rotating the cam shaft relative to the chain sprocket by hydraulic pressure in the vicinity of one cam shaft of the cylinder head and overlapping with the end cam cap. While is open
The end cam cap is provided with a bridge-shaped oil passage for controlling the relative rotation of the other camshaft with respect to the chain sprocket so as to communicate with the head built-in oil passage.
Internal combustion engine.

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