JP2525238Y2 - DOHC engine cylinder head with variable valve timing mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) This invention has a pair of camshafts for opening and closing a suction valve and an exhaust valve respectively in an upper space of a cylinder head covered by a cylinder head cover, and at least one of the camshafts. The present invention relates to a cylinder head in a DOHC engine in which a camshaft is provided with a hydraulically operated variable valve timing mechanism.

(Conventional technology) So-called DOHC (Double Overhead Camshaft)
In an engine of the type, two camshafts rotationally driven by a crankshaft are provided on an upper portion of a cylinder head, and are provided on one of the camshafts at a predetermined opening / closing timing according to the engine speed. The intake valve is opened and closed via a cam, and the exhaust valve is opened and closed via an exhaust cam provided on the other camshaft.

On the other hand, in recent years, there has been an engine for a vehicle or the like in which the opening / closing timing of a valve is changed according to the engine speed in order to improve output performance and the like. For example, Japanese Utility Model Laid-Open Publication No. Sho 62-57711 discloses a hydraulically operated variable valve timing mechanism that changes the phase with respect to a crankshaft at one end of a camshaft. While transmitting the rotational driving force to the camshaft,
A configuration is disclosed in which an electromagnetic solenoid valve for controlling the operating oil pressure of the valve timing mechanism is provided corresponding to the other end of the camshaft.

According to this, for example, by changing the operating oil pressure of the variable valve timing mechanism by operating the electromagnetic solenoid valve according to the engine speed, the phase of the camshaft with respect to the crankshaft changes,
DOHC that requires particularly high output, such as the intake valve and exhaust valve are opened and closed at the optimal opening and closing timing according to the operating condition, and the acceleration performance is improved in each of the low speed range and the high speed range There is an advantage that the output performance of the engine is expected to be improved.

(Problems to be Solved by the Invention) By the way, as in the prior art described in the above publication, the electromagnetic solenoid valve for hydraulic control in the variable valve timing mechanism is arranged on the shaft end side of the camshaft. Since the overall length of the cylinder head becomes longer, there is a disadvantage that the engine becomes larger.

In order to solve such a problem, it is conceivable to dispose the electromagnetic solenoid valve at, for example, a middle part of a cylinder head. Places need to be considered.

In view of this, the present invention provides an electromagnetic solenoid valve that controls the operating oil pressure of the valve timing mechanism in a cylinder head of a DOHC engine equipped with a variable valve timing mechanism. The operating state of a solenoid coil unit that is easily affected by ambient temperature is improved. It is a first object to be able to be installed so as to be maintained at a minimum.

A second object of the present invention is to simplify the structure of the electromagnetic solenoid valve so as to make the solenoid valve compact and to improve the equipment in the cylinder head.

(Means for Solving the Problems) That is, the cylinder head of the DOHC engine according to the invention of claim 1 of the present application (hereinafter, referred to as the first invention) is provided with a suction head in a space above the cylinder head covered by the cylinder head cover. The above-described variable valve, wherein a pair of camshafts for opening and closing the exhaust valve are provided, and at least one of the camshafts is provided with a hydraulically operated variable valve timing mechanism for changing a phase with respect to a crankshaft. An electromagnetic solenoid valve that controls the supply and discharge of hydraulic oil to and from the timing mechanism is mounted so that at least a solenoid coil portion of the solenoid valve is exposed in the upper space of the cylinder head.

Further, a cylinder head of a DOHC engine according to the invention of claim 2 of the present application (hereinafter, referred to as a second invention) is provided with a pair of camshafts for opening and closing intake and exhaust valves, respectively, above the cylinder head. In a configuration in which at least one of the camshafts is provided with a hydraulically operated variable valve timing mechanism that changes the phase with respect to the crankshaft, an electromagnetic solenoid valve that controls supply and discharge of hydraulic oil to and from the variable valve timing mechanism is provided. ,
The hydraulic oil introduction passage, a supply passage for guiding the hydraulic oil to the timing mechanism, and a discharge passage for draining the supply passage are attached to a cylinder head provided respectively. When supplying the timing mechanism, the supply passage and the introduction passage are communicated with each other, and the supply passage and the discharge passage are shut off. When the hydraulic oil is discharged from the timing mechanism, the supply passage and the introduction passage are shut off. A passage connecting the supply passage and the discharge passage is formed.

(Operation) First, according to the configuration of the first invention, an electromagnetic solenoid valve for controlling the supply and discharge of the hydraulic oil to and from the variable valve timing mechanism is arranged such that at least the solenoid coil portion of the solenoid valve is in the upper space of the cylinder head. Since it is mounted so as to be exposed, lubricating oil and the like after lubricating the camshaft and the like frequently collide with the solenoid coil portion. In this case, since the amount of change and the rate of change of the temperature of the lubricating oil are generally small, a sudden temperature change does not occur in the solenoid coil portion where the operation state is easily affected by the ambient temperature. The responsiveness or reliability of the oil supply / discharge control and the durability of the solenoid valve are ensured.

According to the second invention, a cylinder provided with a passage for introducing hydraulic oil to the variable valve timing mechanism, a supply passage for guiding the hydraulic oil to the timing mechanism, and a discharge passage for draining the supply passage. When supplying hydraulic oil to the timing mechanism, the electromagnetic solenoid valve attached to the head shuts off the supply passage and the discharge passage while connecting the supply passage and the introduction passage, and the hydraulic oil is supplied from the timing mechanism. At the time of discharge, a passage communicating with the supply passage and the discharge passage is formed while shutting off the supply passage and the introduction passage, so that the structure of the solenoid valve is simplified and the solenoid valve is compactly configured. Thus, the ease of installation of the solenoid valve in the cylinder head is improved. In addition, the supply passage communicates with the introduction passage when the hydraulic oil is supplied, and is shut off from the discharge passage. When the hydraulic oil is discharged, the supply passage communicates with the discharge passage and is shut off from the introduction passage. At the time of non-operation, the hydraulic oil is quickly discharged from the variable valve timing mechanism, and control responsiveness when the solenoid valve is switched from on to off is enhanced.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. This embodiment is common to the first and second inventions.

As shown in FIGS. 1 and 2, on the upper surface of a cylinder head 2 of the engine 1, a plug hole boss portion 3 for each cylinder is protruded at a substantially central position in a width direction thereof.
The first and second camshafts 4,
5 are allocated and distributed. Intermediate portions of the first and second camshafts 4 and 5 are connected to the boss portion 3 and beam portions 8a and 8b respectively provided between left and right side walls 6 and 7 of the cylinder head 2; The bearings are rotatably supported by cam caps 9, 9 bolted to the beam portions 8a, 8b, respectively. The first camshaft 4 located on the left side in the drawing has a pair of exhaust cams 10, 10 provided for each cylinder with the beam portion 8a interposed therebetween, and the first camshaft 4 is located on the right side in the drawing. 2 camshaft 5
Has a pair of intake cams 1 with the beam portion 8b interposed therebetween.
1, 11 are provided for each cylinder.

Here, an outline of the valve operating mechanism in the present embodiment will be described. As shown in FIG. 2, one end side of the valve lash adjuster mechanism is hydraulically operated below the exhaust cam 10 on the first camshaft 4. An exhaust swing arm 14a swingably supported by a pivot 13 of 12a is provided,
The lower surface of the other end of the swing arm 14a is the exhaust valve 15
And a roller 16 provided at an intermediate portion thereof is in sliding contact with the lower surface of the exhaust cam 10. On the other hand, also below the intake cam 11 on the second camshaft 5, an intake swing arm 14b is provided, one end of which is swingably supported by a pivot 13 of a hydraulically operated valve lash adjuster mechanism 12b. I have. Also in this case, the lower surface on the other end side of the intake swing arm 14b is in contact with the stem end 17a of the intake valve 17, and the roller 16 provided at the intermediate portion slides on the lower surface of the intake cam 11. ing. That is, by rotating the first camshaft 4, the exhaust swing arm 14a swings up and down with the pivot 13 of the valve lash adjuster mechanism 12a as a fulcrum while tracing the outer peripheral surface of the exhaust cam 10. Above exhaust valve 15
Performs a vertical opening and closing movement, while the second camshaft 5
, The suction swing arm 14b swings up and down around the pivot 13 of the bubble lash adjuster mechanism 12b while tracing the outer peripheral surface of the intake cam 1, and the intake valve 17 moves up and down accordingly. Opening and closing movement.

A valve mechanism including the first and second camshafts 4 and 5 and the swing arms 14a and 14b driven by the two camshafts 4 and 5 is housed in the upper portion of the cylinder head 2. A cylinder head cover 19 that covers the upper space 18 is mounted between the left and right side edge portions of the cylinder head cover 19 and the sealing surfaces respectively provided on the tops of the left and right side walls 6 and 7 of the cylinder head 2. Is provided with an oil-tight rubber seal 20 interposed therebetween.

On the other hand, on the front end side of the cylinder head 2, a bearing flange portion 21 that supports the lower half portions of the first and second camshafts 4 and 5, respectively, protrudes. An end cap 22 that covers the upper half of the first and second camshafts 4 and 5 is disposed between the two camshafts 4 and 5, and on both sides of each camshaft 4 and 5. 23 are integrally fixed to the bearing flange 21 via bolts 23.

At the front end of the cylinder head 2, a front side wall 24 that partitions the upper space 18 of the head 2 is provided continuously with the left and right side walls 6 and 7. The front side wall 24 has a substantially V-shaped central portion bulging forward, and has a sealing surface flush with the sealing surfaces of the left and right side walls 6, 7 on both sides of the central portion. First and second camshafts 4,
Notch portions 24a and 24b which are cut out downward at positions corresponding to 5 are formed. Overhangs 22a, 22b extending the end cap 22 rearward are fitted into these notches 24a, 24b, respectively, and the first and second cams are formed by these overhangs 22a, 22b. The upper parts of the shafts 4 and 5 are respectively covered. Further, the front ends of the overhang portions 22a and 22b are
4 is cut out corresponding to the inner side surface, and a sealing surface is provided at an upper portion thereof so as to be flush with the sealing surface at the central portion. As a result, the left and right side walls on both sides are provided above the front side wall 24 of the cylinder head 2.
The sealing surfaces flush with the sealing surfaces on 6, 7 are continuously formed.

The shaft end portions of the first and second camshafts 4 and 5 penetrate between the bearing flange portion 21 and the end cap 22 and protrude outward, respectively. The first cam pulley 25 is attached directly to
A second cam pulley 27 is attached to the protruding end of the second camshaft 5 via a hydraulically operated variable valve timing mechanism 26 (detailed structure will be described later). And
A timing belt 28 for transmitting a rotational driving force of a crankshaft (not shown) is wound around the first and second cam pulleys 25 and 27. When the timing belt 28 is driven by the crankshaft, the timing belt 28 is driven. 1,
The second camshafts 4, 5 rotate synchronously. The bearing flange 21 and the end cap
A belt cover 29 for protecting the timing belt 28 is attached to the front end side of the cover 22 so as to cover the first and second cam pulleys 25 and 27 and the variable valve timing mechanism 26.

Here, the variable valve timing mechanism 26 will be described. As shown in FIG. 1, the variable valve timing mechanism 26 has a second end in a state where a shaft portion at one end is inserted into the bearing flange portion 21 of the cylinder head 2. A bellmouth-shaped mounting flange portion 30 which is externally fitted to the camshaft 5 so as to be relatively rotatable; and a substantially cylindrical central block 32 also connected to the protruding end portion of the second camshaft 5 via a hollow bolt 31. A ring piston 33 externally fitted to the center block 32, a hollow cylindrical cover body 34 having one end fixed to the mounting flange 30 so as to cover the center block 32 and the ring piston 33; A cover 35 is attached to the other end of the cover 34 in an oil-tight manner.
The second cam pulley 27 is fixed via 6, 36, and the center block 32 and the ring piston 33 are fitted by a spiral engaging groove structure. And is fitted by a spiral engagement groove structure.

The hollow bolt 31 connecting the center block 32 to the second camshaft 5 has a communication passage 37 penetrating in the axial direction thereof.
An oil chamber 38 provided inside the lid 35 and a hollow passage 39 formed in the axial direction of the second camshaft 5 are communicated via the communication passage 37. .

As shown in FIG. 3, in the radial direction of the second camshaft 5, oil passages 40, 40 having one end opened facing the hollow passage 39 are formed in a straight line, and In the bearing flange portion 21 of the head 2 and the end cap 22 fixed to the flange portion 21 via bolts 23, 23, a circumferential groove 41 surrounding the entire circumference of the second camshaft 5 is provided with the oil groove. The circumferential grooves 41 communicate with a supply passage 42 for hydraulic oil provided in the cylinder head 2. That is, this supply passage 42
The hydraulic oil which has flowed into the circumferential groove 41 via the oil passages 40, 40 provided in the second camshaft 5 is supplied to the hollow passage 39, and the hydraulic oil is supplied to the communication passage of the hollow bolt 31.
After passing through 37, it is introduced into the oil chamber 38.

A conductive path 43 is formed in the cover body 34 to supply hydraulic oil guided to the oil chamber 38 to one end face of the ring piston 33 and apply hydraulic pressure to the piston 33. A return spring 44 that urges the ring piston 33 against hydraulic pressure is located on the opposite side of the conduction path 43 and is interposed between the piston 33 and the mounting flange 30.

Therefore, in the valve timing mechanism 26, when hydraulic pressure acts on the ring piston 33, the piston 33
Moves in the axial direction against the return spring 44. In that case, since the center block 32 and the cover body 34 located inside and outside the ring piston 33 are mutually engaged with the piston 33 by a spiral engagement groove structure, the movement of the ring piston 33 The center block 32 and the cover body 34 rotate relative to each other, whereby the second camshaft 5 and the second cam pulley 27
Also rotate relatively, and a phase difference occurs between the second camshaft 5 and the crankshaft, so that the opening / closing timing of the intake valve 17 changes. Conversely, when the hydraulic oil supplied to the valve timing mechanism 26 is discharged to release the hydraulic pressure acting on the ring piston 33, the piston
33 is pushed back by the return spring 44 to return to the original opening / closing timing.

As shown in FIGS. 1 and 2, the cylinder head 2 is provided with a mounting hole 46 for mounting an electromagnetic solenoid valve 45 for controlling the supply and discharge of hydraulic oil to and from the variable valve timing mechanism 26. ing. The first and second camshafts covered by the cylinder head cover 19 are provided in the mounting holes 46.
4 and 5, specifically, near the center of the front wall 24 near the variable valve timing mechanism 26, and as shown in FIG. 4, the lower end of the upper large-diameter portion 46 a The small-diameter portion 46c is formed in a vertically elongated shape that extends downward continuously from the intermediate step portion 46b provided on the side.

The other end of the hydraulic oil supply passage 42, one end of which is open to the peripheral groove 41 surrounding a half circumference of the second camshaft 5, is opened on the peripheral surface of the small diameter portion 46c on the lower side of the mounting hole 46. In addition, one end of a high-pressure hydraulic oil introduction passage 47 pressurized by an oil pump (not shown) is opened at a position above the supply passage 42.
And, at four places near the lower end of the small diameter portion 46c, the fifth
As shown in the drawing, hydraulic oil discharge passages 48 are opened in a cross shape.

On the other hand, as shown in FIG. 2, the electromagnetic solenoid valve 45 mounted in the mounting hole 46 having the above-described shape is provided with a vertically-long small-diameter valve body 49 having a valve body described later, A large-diameter solenoid coil unit 50 provided on the upper part of the valve body 49 and operating the valve body is basically configured, and the solenoid valve 45 is provided at a substantially middle portion between the upper and lower sides of the solenoid coil unit 50. A flange portion 50a for fixing to the cylinder head 2 is provided.

The electromagnetic solenoid valve 45 having such a shape is inserted so that the bottom surface of the solenoid coil portion 50 is seated on the intermediate step portion 46b in the mounting hole 46, and the upper half portion of the solenoid coil portion 50 Are exposed in the upper space 18 of the cylinder head 2 near the front side wall 24. The electromagnetic solenoid valve 45 is fixed by two bolts 51, 51 screwed into the cylinder head 2 through the flange portion 50a.

On the other hand, as shown in FIG. 4, the valve element 49 of the electromagnetic solenoid valve 45 has a bottomed cylindrical housing 52 fixed to the solenoid coil portion 50 and a vertically movable lower part of the housing 52. And a rod portion 54 hanging downward from the solenoid coil portion 50. The lower end of the rod portion 54 comes into contact with the upper portion of the valve body 53. And, in the middle part of the housing 52,
A hydraulic oil introduction port 52a is provided so as to communicate with the opening of the introduction passage 47, and the introduction port 5
Above 2a, a hydraulic oil supply / discharge port 52b is provided so as to communicate with the opening of the supply passage 42 in the mounting hole 46. In the vicinity of the lower end of the housing 52, a fifth
As shown in the figure, four drain ports 52c... 52c are provided at 90 ° intervals in the circumferential direction so as to communicate with the openings of the discharge passages 48.

Further, the valve body 53 is located above the supply / discharge port 52b and is in contact with an upper land portion 53a which is in sliding contact with the inner wall of the housing 52.
And has a slightly longer lower land portion 53b slidably in contact with the inner wall of the housing 52, and a small-diameter portion 53c connecting the both,
The lower land portion 53b is provided with a hollow spring chamber 55 having an open lower end, and a lower portion of the housing 52 is provided between the receiving portion provided in the lower land portion 53b at an intermediate portion of the spring chamber 55 and the lower portion. A return spring 56 is interposed therebetween. In this embodiment, the valve body 53 has a relief passage 58 for communicating a peripheral chamber 57 formed around the small diameter portion 53c with a spring chamber 55 formed inside the lower land portion 53b. Are formed.

That is, in the electromagnetic solenoid valve 45, when the solenoid coil portion 50 is energized and operated, the rod portion 54 moves down and the valve body 53 moves downward against the return spring 56. Then, as shown in FIG. 4, the introduction port 52 provided in the housing 52 is provided.
a and the supply / discharge port 52b are connected to each other via a peripheral chamber 57 formed between the upper land portion 53a and the lower land portion 53b of the valve body 53, and are provided on the housing 52 by the lower land portion 53b. The drain ports 52c... 52c are closed. Thereby, the introduction passage 47 provided in the cylinder head 2 is provided.
High-pressure hydraulic oil supplied to the inlet port 52a
After flowing into the peripheral chamber 57 through the supply / discharge port 52b, it flows into the supply / discharge passage 42 and is supplied to the variable valve timing mechanism 26.

On the other hand, when the energized state to the solenoid coil section 50 is cut off, the rod section 54 moves upward and the valve element 53
Receives the urging force of the return spring 56 and moves upward with the upward movement of the rod portion 54. Then, as shown in FIG. 6, the introduction port 52 provided in the housing 52 is provided.
a is closed by the lower land portion 53b of the valve body 53, and the peripheral side wall 57 communicating with the supply passage 42 via the supply / discharge port 52b is formed by the relief passage 58 and the spring chamber 55.
Through the drain ports 52c... 52c. Therefore, the hydraulic oil in the supply passage 42 is released to the discharge passages 48... 48 via the drain ports 52c... 52c, thereby releasing the hydraulic oil acting on the ring piston 33 in the valve timing mechanism 26. As a result, the timing mechanism 26 returns to the initial state.

As described above, since the relief passage 58 for allowing the hydraulic oil in the supply passage 42 to escape is formed in the valve body 53 built in the valve body 49 of the electromagnetic solenoid valve 45, the valve body 49 is compact. Thus, the equipment of the electromagnetic solenoid valve 45 in the cylinder head 2 is improved. Also, when the electromagnetic solenoid valve 45 is not operated, the supply passage 42 communicates with the discharge passages 48... 48 via the relief passage 58 and is cut off from the introduction passage 47.
Hydraulic oil is quickly discharged from 26, thereby improving control responsiveness when the electromagnetic solenoid valve 45 is switched from on to off.

Further, a pair of upper and lower circumferential projections 50b, 50b are provided at an upper end portion of the solenoid coil portion 50 in the electromagnetic solenoid valve 45.
c is provided. On the other hand, the above-mentioned cylinder head cover 19 which covers the upper space 18 of the cylinder head 2 is provided with a cylindrical portion 19a which surrounds the periphery of the solenoid coil portion 50 of the solenoid valve 45 in an annular shape and is bent downward. The lower end edge of the cylindrical portion 19a extends so as to correspond to the lower circumferential protrusion 50c provided on the solenoid coil portion 50, and is located between the circumferential protrusion 50c and the upper circumferential protrusion 50b. In
An O-ring 59 is fitted so as to contact the inner peripheral surface of the cylindrical portion 19a.

As described above, since the solenoid coil portion 50 of the electromagnetic solenoid valve 45 is exposed in the upper space 18 of the cylinder head 2 covered by the cylinder head cover 19, the lubricating oil and the like supplied to the bearing portion of the cam shaft And collides with the solenoid coil unit 50 frequently. In that case,
Generally, lubricating oil has a small amount of change and a small change in temperature.
Abrupt temperature changes do not occur in the solenoid coil unit 50, whose operation state and the like are easily affected by the ambient temperature, and as a result, the responsiveness or reliability of the hydraulic oil supply / discharge control to the variable valve timing mechanism, and the electromagnetic solenoid valve 45 Durability will be ensured.

(Effects of the Invention) As described above, according to the first invention, the electromagnetic solenoid valve that controls the supply and discharge of the working oil to and from the variable valve timing mechanism is such that at least the solenoid coil portion of the solenoid valve is located in the upper space of the cylinder head. Since it is mounted so as to be exposed, splashed oil after lubricating the camshaft etc. does not cause a rapid temperature change in the solenoid coil section, etc., thereby controlling the supply and discharge control of hydraulic oil to the variable valve timing mechanism. Responsiveness or reliability and durability of the solenoid valve are ensured.

According to the second invention, a cylinder head provided with a passage for introducing hydraulic oil to the variable valve timing mechanism, a supply passage for guiding the hydraulic oil to the timing mechanism, and a discharge passage for draining the supply passage is provided. When supplying hydraulic oil to the above-mentioned timing mechanism, the supplied electromagnetic solenoid valve is connected to the supply passage and the introduction passage, shuts off the supply passage and the discharge passage, and discharges the hydraulic oil from the above-mentioned timing mechanism. In this case, since a passage that connects the supply passage and the discharge passage while blocking the supply passage and the introduction passage is formed, the structure of the solenoid valve is simplified, and the solenoid valve is compactly configured. Thereby, the equipment of the solenoid valve in the cylinder head is improved. In addition, the supply passage communicates with the introduction passage when the hydraulic oil is supplied, and is shut off from the discharge passage. When the hydraulic oil is discharged, the supply passage communicates with the discharge passage and is shut off from the introduction passage. At the time of non-operation, the hydraulic oil is quickly discharged from the variable valve timing mechanism, and control responsiveness when the solenoid valve is switched from on to off is enhanced.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a partial plan view of an engine with a part cut away, and FIG.
FIG. 3 is a sectional view taken along the line II-II, and FIG.
FIG. 4 is a schematic enlarged cross-sectional view taken along the line III-III, and FIG. 4 is a main part of the electromagnetic solenoid valve in an operating state viewed along the line IV-IV in FIG. FIG. 5 is a cross-sectional view taken along the line VV in FIG. 4, and FIG. 6 is an enlarged side view of a main part in which a part of an electromagnetic solenoid valve in a non-operating state is cut away. FIG. 2 ... Cylinder head, 4 ... First camshaft, 5 ... Second
Camshaft, 15 ... exhaust valve, 17 ... intake valve, 18 ...
Upper space, 19… Cylinder head cover, 26… Variable valve timing mechanism, 45… Electromagnetic solenoid valve, 50… Solenoid coil part, 42… Supply passage, 47… Introduction passage, 48… Discharge passage, 55… Valve, 58… Relief aisle.

Claims (2)

(57) [Scope of request for utility model registration] 1. A pair of camshafts for opening and closing intake and exhaust valves, respectively, are provided in an upper space of a cylinder head covered by a cylinder head cover.
A cylinder head of a DOHC engine provided with a hydraulically operated variable valve timing mechanism that changes a phase with respect to a crankshaft on at least one of the camshafts, the electromagnetic head being configured to supply and discharge hydraulic oil to and from the variable valve timing mechanism. A cylinder head for a DOHC engine equipped with a variable valve timing mechanism, wherein a solenoid valve is mounted so that at least a solenoid coil portion of the solenoid valve is exposed in the upper space of the cylinder head. 2. A hydraulically operated variable valve having a pair of camshafts for opening and closing a suction valve and an exhaust valve, respectively, disposed at an upper portion of a cylinder head, wherein at least one of the camshafts changes a phase with respect to a crankshaft. A cylinder head of a DOHC engine provided with a timing mechanism, wherein an electromagnetic solenoid valve that controls supply and discharge of hydraulic oil to and from the variable valve timing mechanism is attached to the cylinder head. , A supply passage for guiding hydraulic oil to the timing mechanism, and a discharge passage for draining the supply passage are provided, and the electromagnetic solenoid valve supplies hydraulic oil to the timing mechanism. When connecting the supply passage and the introduction passage, the supply passage and the discharge passage are shut off, A cylinder head of a DOHC engine equipped with a variable valve timing mechanism, wherein a passage connecting the supply passage and the discharge passage is formed while shutting off the supply passage and the introduction passage when discharging from the timing mechanism. .