JP2701609B2 - V-type internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a V-type internal combustion engine provided with a variable valve timing mechanism which is operated by a hydraulic pressure in each of the valve trains of left and right banks.

[0002]

2. Description of the Related Art The optimum values of the opening / closing timing of intake and exhaust valves and the amount of valve overlap of an internal combustion engine differ depending on the operating conditions of the engine, for example, the engine speed.

Therefore, a cam pulley or a cam sprocket around which a timing belt or a timing chain is wound is rotatably mounted on the camshaft, and the two are relatively rotated by a predetermined angle by a hydraulic actuator using a helical gear or the like. Various variable valve timing mechanisms capable of changing the phase of the camshaft with respect to the crank angle in two ways have been conventionally proposed, and some of them have been put to practical use (for example, see Japanese Patent Application Laid-Open No. 55-96311). ).

In this case, as disclosed in the above publication, a hydraulic actuator is disposed at the end of the camshaft, and lubricating oil pumped from an oil pump of the engine is supplied to the cam bearing of the cylinder head. The oil is introduced into the oil passage inside the camshaft through the section, and is supplied to the actuator through the oil passage. The switching of the valve timing, that is, the switching of whether or not to operate the actuator is performed by a hydraulic control valve provided on the cylinder head side.

[0005]

By the way, if the above-described variable valve timing mechanism is applied to a V-type internal combustion engine, the hydraulic control valve is generally used because the hydraulic actuator is provided at the camshaft end of each bank. It will be arranged individually for each cylinder head. However, providing the hydraulic control valves individually in the left and right banks of the V-type internal combustion engine is not preferable because not only the number of parts is increased but also the configuration of the harness and the like becomes complicated. Further, when only one of the hydraulic control valves of one bank malfunctions, the valve opening / closing timing of each cylinder becomes irregular.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a V-shaped actuator having a variable valve timing actuator for relatively changing the phase between the camshaft and the crankshaft at the ends of the camshafts of the left and right banks by hydraulic pressure. In the internal combustion engine, a control valve mounting flange is formed upward at a position between the V banks of the cylinder block, and a hydraulic passage communicating with a hydraulic pressure source and a hydraulic passage communicating with the actuator of the left and right banks are respectively provided on the flange of the flange. A hydraulic control valve is provided on the flange, the hydraulic control valve being configured to be open on the surface and to switch and control the communication state of the hydraulic passages.

[0007]

The hydraulic pressure supplied from the hydraulic pressure source is applied to the variable valve timing actuators of the left and right banks via a hydraulic control valve disposed at a position between the V banks of the cylinder block. Can be switched. That is, the valve opening / closing timing of the left and right banks can be simultaneously switched by a single hydraulic control valve. Further, the hydraulic control valve is disposed in a manner to effectively use the empty space between the banks.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to FIGS.

This embodiment is an example of a V-type six-cylinder engine. As shown in FIG. 1, cylinder heads 2 are fixed to upper surfaces of left and right banks of a cylinder block 1, respectively, and are shown in FIG. As described above, the oil pan 3 is attached to the lower surface of the cylinder block 1 and the chain case rear 4 and the chain case front 5 are provided at the front end of the engine.
Thus, a chain chamber 6 is formed. 2, 7 is a crankshaft, 8 is a crank pulley,
Reference numeral 9 denotes an intake manifold located between the banks.

Each cylinder head 2 has a DOHC type valve operating mechanism, and an intake camshaft 10 is provided inside the bank.
(See FIG. 4), and an exhaust-side camshaft (not shown) is arranged outside the bank. The camshafts 10 and the like are driven in synchronization with the crankshaft 7 by a timing chain 11 passing through the inside of the chain chamber 6. As shown in FIG. 4, a variable valve timing actuator 12 is provided at the front end of the intake camshaft 10. The actuator 12 has an inner cylinder 13 fixed to the camshaft 10, a cup-shaped outer cylinder 15 having a cam sprocket portion 14 on the outer periphery, and an inner peripheral surface of the inner cylinder 13 and an inner peripheral surface of the outer cylinder 15 meshed with each other. Helical gear piston 16
The inner cylinder 13 and the outer cylinder 15 rotate relative to each other with the axial movement of the piston 16 due to the helical gear meshing. That is, the phase of the crankshaft 7 and the phase of the camshaft 10 linked via the timing chain 11 can be relatively changed by a predetermined angle. The ON operation hydraulic passage 17 communicates with the pressure receiving surface at one end of the piston 16, and the OFF operation hydraulic passage 1 communicates with the pressure receiving surface at the other end.
8 are in communication. Therefore, the piston 16 is driven in the axial direction by applying hydraulic pressure from either one.

The ON operation hydraulic passage 17 is opened to the # 1 cam journal through the inside of the camshaft 10, and is connected to the cylinder head 2 via a cam bracket (not shown).
ON operation hydraulic port 2 near # 1 cam bearing portion 19 on the side
It communicates with 0. The hydraulic passage 18 for OFF operation is
Similarly, it opens inside the camshaft 10 to the # 2 cam journal, and communicates with the OFF operation hydraulic port 22 of the # 2 cam bearing 21 on the cylinder head 2 side.

On the other hand, as shown in FIGS. 1 and 3, between the V banks of the cylinder block 1, a control valve mounting flange 23 is formed so as to face upward. The control valve mounting flange 23 is located slightly forward of the center of the cylinder block 1 in the front-rear direction, and a cooling water outlet flange 24 is formed behind the control valve mounting flange 23.

On the flange surface 23a of the control valve mounting flange 23, a pair of ON operation hydraulic passages 25 corresponding to the left and right banks and a pair of O
An FF operation hydraulic passage 26, a hydraulic supply passage 27, and a return passage 28 are open. As shown in FIG. 1, the ON-operation hydraulic passage 25 is formed in a substantially V-shape, and has a leading end connected to the ON-operation hydraulic passage 29 on the cylinder head 2 side. The cylinder head 2 communicates with the ON-operation hydraulic port 20 of the # 1 cam bearing portion 19 through the ON-operation hydraulic passage 29 on the cylinder head 2 side. The hydraulic path to the ON-operation hydraulic port 20 has substantially the same configuration in the left and right banks. The hydraulic passage 26 for OFF operation is also formed in a substantially V-shape, and its tip is connected to a cylinder head bolt hole 30 which also serves as an oil passage. A hydraulic passage 31 for OFF operation inside the cylinder head 2 is further connected to the cylinder head bolt hole 30.
The tip of the operating hydraulic passage 31 is the # 2 cam bearing 2 described above.
1 is connected to the OFF operation hydraulic port 22. still,
The hydraulic path to the OFF-operation hydraulic port 22 has substantially the same configuration in the left and right banks.

The hydraulic supply passage 27 extends linearly downward and communicates with a main gallery 32 at the center of the cylinder head 2. In addition, the return passage 28 is provided in FIG.
As shown in FIG. 2, the tip extends downward into the crankcase.

The control valve mounting flange 23 has a hydraulic control valve 3 for switching and controlling the communication state of each hydraulic passage.
3 is attached. The hydraulic control valve 33 includes a flange portion 33a that covers the control valve mounting flange 23,
It has a valve portion 33b accommodating a spool valve to be described later, and a solenoid 33c projecting obliquely upward. FIG.
The details of the hydraulic control valve 33 are shown in FIG.
4, a cylindrical valve sleeve 35 is fitted and fixed, a cylindrical spool valve 36 is slidably fitted on the inner periphery of the valve sleeve 35, and the spool valve 36 The spring 37 urges the push rod 38 of the solenoid 33c.
In the valve sleeve 35, the hydraulic passage 25 for ON operation is provided.
, A first outlet port 39 communicating with the hydraulic supply passage 27, an inlet port 40 communicating with the hydraulic supply passage 27, and a hydraulic passage 26 for the OFF operation.
And a second outlet port 41 communicating with the second port. The spool valve 36 has an inlet port 40,
A concave portion 42 communicating with one of the second outlet ports 39 and 41 and a communication hole 43 at a base end portion capable of communicating with the first outlet port 39 are provided. And, the spool valve 36
A drain port 44 which is always in communication with the hollow portion of the valve sleeve 35 is provided at the distal end, and the drain port 44 communicates with the above-described return passage 28.

FIG. 5 shows a state of the flow path when the solenoid 33c is in a non-excited state.
Located on the side. Therefore, the high-pressure lubricating oil flowing from the hydraulic pressure supply passage 27 passes through the concave portion 42 and enters the inlet port 40.
To the first outlet port 39, and is supplied to the variable valve timing actuator 12 through the hydraulic passages 25, 29, 17 for ON operation. As a result, the actuator 12 is turned on, and the cam sprocket 1
The intake camshaft 10 rotates by a fixed amount with respect to the camshaft 4. Also, at this time, the second outlet port 41 is in communication with the drain port 44, so that the lubricating oil existing on the opposite side of the piston 16 is turned off by the hydraulic passages 18, 31, for OFF operation.
It is discharged to a return passage 28 through 26.

On the other hand, FIG. 6 shows a state of the flow path when the solenoid 33c is in the excited state. The spool valve 36 is pushed by the push rod 38 and located at the distal end, and the inlet port 40 is The two outlet ports 41 communicate with each other. Therefore, the high-pressure lubricating oil is supplied to the hydraulic passage 2 for OFF operation.
The actuator is supplied to the variable valve timing actuator 12 through 6, 31, and 18. As a result, the actuator 12 is turned off, and the cam sprocket portion 14 is turned off.
And the camshaft 10 returns to the initial state. At this time, the first outlet port 39 is connected to the communication hole 43.
, The lubricating oil existing on the opposite side of the piston 16 is discharged to the return passage 28 through the hydraulic passages 17, 29, 25 for ON operation.

A pair of ON operation hydraulic passages 25 and OF of the left and right banks opened to the control valve mounting flange 23 are provided.
The F-operation hydraulic passage 26 is connected to each other by substantially L-shaped oil grooves 45 and 46 (see FIG. 3) provided on the back surface of the flange portion 33 a of the hydraulic control valve 33.

As described above, according to the configuration of the above embodiment, the variable valve timing actuators 12 of the left and right banks are used.
Can be switched by one hydraulic control valve 33, the number of parts is reduced, and the configuration is simplified. In addition, the valve timings of the left and right banks can always be switched simultaneously. The intake-side camshaft 10 having the actuator 12 is arranged inside the bank, whereas the hydraulic control valve 33 is located between the V banks. The hydraulic path up to this point does not become extremely long, and does not cause problems such as a decrease in responsiveness.
As shown in FIG. 2, the hydraulic control valve 33 is disposed so as to effectively use the empty space generated between the cylinder block 1 and the intake manifold 9 between the V banks, and does not project outside. Therefore, the size of the entire engine can be reduced.

In the above-described embodiment, both the ON switching and the OFF switching of the variable valve timing actuator 12 are performed by hydraulic pressure supply, but only one of them is performed by hydraulic pressure supply, and the other is by the return spring. It is also possible to adopt a configuration in which the operation is performed with a spring force.

[0021]

As is apparent from the above description, according to the V-type internal combustion engine according to the present invention, the switching of the hydraulic variable valve timing actuator provided in the left and right banks is performed by one hydraulic control valve. Therefore, the number of parts can be reduced and the configuration can be simplified, and the valve timings of the left and right banks can always be switched at the same time.
Further, by arranging the hydraulic control valve using an empty space between the V banks, it is possible to avoid an increase in the size of the engine.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a V-type internal combustion engine according to the present invention.

FIG. 2 is a vertical sectional view of a V-type internal combustion engine according to the present invention.

FIG. 3 is a plan view of a cylinder block.

FIG. 4 is a plan view showing a cylinder head together with an intake camshaft.

FIG. 5 is a sectional view of a main part of the hydraulic control valve.

FIG. 6 is a cross-sectional view of a main part of the hydraulic control valve showing a state at the time of hydraulic pressure switching.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cylinder block 2 ... Cylinder head 10 ... Intake side camshaft 12 ... Variable valve timing actuator 23 ... Control valve mounting flange 25 ... ON operation hydraulic path 26 ... OFF operation hydraulic path 27 ... Hydraulic supply path 28 ... Return Passage 33: Hydraulic control valve

Claims (1)

(57) [Claims] 1. A V-type internal combustion engine comprising a variable valve timing actuator for relatively changing the phase between a camshaft and a crankshaft relative to the camshaft ends of left and right banks by hydraulic pressure. In this position, a control valve mounting flange is formed facing upward, and a hydraulic passage communicating with a hydraulic pressure source and a hydraulic passage communicating with the actuator of the left and right banks are respectively opened on the flange surfaces of the flanges. A V-type internal combustion engine, wherein a hydraulic control valve for switching control of the communication state of the internal combustion engine is attached to the flange.