JPH05256115A - Valve system of internal combustion engine - Google Patents

Abstract

PURPOSE:To obtain sitting speed of an engine valve which is suitable for operating condition by making throttle action ineffective through a process of releasing oil pressure in a damper chamber according to operating condition of an engine. CONSTITUTION:Oil pressure generated by rotation of a cam according to the opening timing of an intake valve 6 is exerted from an oil supplying passage 25 into a damper chamber 14, and a valve driving piston 11 in pushed down so as to have the intake valve 6 driven in opening. When oil pressure is reduced after the intake valve 6 is fully opened, the intake valve 6 is driven in closing direction by the action of a valve spring, so that also the valve driving piston 11 goes up, and oil in the damper chamber 14 is returned to an oil supply passage 25 through an opening/closing valve 48 and a check valve 49. In this case, a throttle mechanism 36 is not operated. Therefore incomplete seating of the intake valve 6 due to large throttle degree is not generated by full lift operation of the intake valve 6 when rotation of an engine is high, or operating oil is in high viscosity condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve drive piston, one end of which is linked to and connected to an engine valve which is spring-biased in a valve closing direction, is slidably fitted to a cylinder body, In the damper chamber formed between the end and the cylinder body, a hydraulic pressure generation unit that generates hydraulic pressure in response to the opening timing of the engine valve,
In addition, the oil supply passage that is connected to the hydraulic pressure releasing means that can release the hydraulic pressure according to the operating state of the engine controls the check valve that allows only the inflow of the hydraulic oil toward the damper chamber and the outflow amount of the hydraulic oil from the damper chamber. The present invention relates to a valve train for an internal combustion engine, which is connected via a restricting throttle mechanism.

[0002]

2. Description of the Related Art Conventionally, such an apparatus is disclosed in, for example, Japanese Patent Publication No.
It is already known from Japanese Patent Laid-Open No. 2-35813 and so on, and a damper chamber facing the back surface of a valve drive piston that is interlocked with and connected to an engine valve is provided with a hydraulic pressure generating means for generating a hydraulic pressure corresponding to the opening timing of the engine. The engine valve is opened and closed by being guided.

[0003]

By the way, in such a valve operating system, between the hydraulic pressure generating means and the damper chamber, there is a check valve which allows only the flow of the hydraulic oil from the hydraulic pressure generating means to the damper chamber, and the hydraulic pressure from the damper chamber. A throttling mechanism that limits the amount of hydraulic oil returned to the generating means is provided to prevent the engine valve from being shockedly seated during the closing operation of the engine valve to prevent damage to the engine valve. .. However, in the above-mentioned conventional one, since the degree of throttling by the throttling mechanism is constant, it is greatly affected by changes in the engine speed and the viscosity of the hydraulic oil.
Especially in full lift operation of the engine valve when the engine is rotating at high speed or when the hydraulic oil has a high viscosity, the degree of throttling of the throttle mechanism increases substantially, and the engine valve does not fully seat even during the compression stroke of the engine. , May adversely affect combustion. Further, the throttle mechanism prevents bounce of the engine valve, but in the full lift operation region, the engine valve is seated according to the cam profile, so the throttle action of the throttle mechanism is substantially unnecessary.

The present invention has been made in view of the above circumstances, and makes it possible to control the seating speed of an engine valve according to the operating state of the engine by invalidating the throttle action of the throttle mechanism according to the operating state of the engine. It is an object to provide a valve operating system for an engine.

[0005]

In order to achieve the above object, the device according to the first aspect of the present invention comprises a damper chamber hydraulic pressure releasing means capable of bypassing the throttling mechanism and communicating between the damper chamber and the oil supply passage. An operating state detecting means for detecting an operating state of the engine and a damper chamber hydraulic pressure releasing means for invalidating the throttling action of the throttling mechanism in response to the operating state detecting means detecting that the engine is in a predetermined operating state. And a control means for controlling the communication state.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the damper chamber hydraulic pressure releasing means bypasses the throttle mechanism and communicates between the damper chamber and the oil supply passage. An operating state detecting means for detecting whether or not it is provided.

According to the third aspect of the present invention, in addition to the configuration of the second aspect, the control means can execute the operation control of the hydraulic pressure releasing means according to the operating state of the engine, and the damper. When the operation state detecting means detects that the chamber hydraulic pressure releasing means is in the communicating state, the hydraulic pressure releasing operation of the hydraulic pressure releasing means is prohibited at least when the engine valve is in the valve opening period.

Further, according to a fourth aspect of the present invention, in addition to the configuration of the second aspect, the control means can execute the operation control of the hydraulic pressure releasing means according to the operating state of the engine, and When the operating state detecting means detects that the damper chamber hydraulic releasing means is in the communicating state in the operating region of the engine where the hydraulic releasing means should perform the hydraulic releasing operation, the hydraulic releasing operation of the hydraulic releasing means is maintained in the entire stroke of the engine. Configured to.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of an engine, FIG. 2 is an enlarged view of a main part of FIG. 1, and FIG. FIG. 4 is a plan view and FIG. 4 is a sectional view corresponding to FIG. 2 in a state where the hydraulic pressure in the damper chamber is released.

First, in FIG. 1, a portion corresponding to each cylinder of the cylinder head 1 in this multi-cylinder internal combustion engine is
An intake valve port 4 is provided so as to face the ceiling surface of the combustion chamber 2, and an intake port 5 that opens to one side surface of the cylinder head 1 through the intake valve port 4 is provided. And intake valve opening 4
An intake valve 6 as an engine valve capable of opening and closing is supported by the cylinder head 1 so as to be openable and closable. Is urged towards.

The valve operating device for driving the intake valve 6 is constructed so as to generate a hydraulic pressure corresponding to a valve opening timing of the intake valve 6 and valve driving means 8 which is interlocked with and connected to the intake valve 6. And a hydraulic pressure generating means 9 connected to the driving means 8.

Referring also to FIG. 2, the valve driving means 8 is
A first cylinder body 10 fixedly arranged above the intake valve 6 and a valve drive piston 11 slidably fitted in the cylinder body 10 are provided. A support block 12 is coupled to the upper part of the cylinder head 1, and the first cylinder body 10 is fixed to the support block 12 coaxially with the intake valve 6. The cylinder body 10 is provided with a cylinder hole 13 that opens toward the intake valve 6, and a valve drive piston 11 whose one end is in contact with the upper end of the intake valve 6 is slidably fitted into the cylinder hole 13. A damper chamber 14 is defined between the other end of the valve drive piston 11 and the cylinder body 10.

On the other hand, the hydraulic pressure generating means 9 is interlocked with and connected to a crankshaft (not shown) at a reduction ratio of 1/2, is rotatably supported by the cylinder head 1, and the intake valve 6 is connected.
Cam with a cam profile corresponding to the valve opening timing of
Camshaft 16 provided with the first cylinder body 1
A second cylinder body 17 fixed to the support block 12 in parallel with the cylinder body 10 at a position adjacent to 0, a cam driven piston 18 slidably fitted in the cylinder body 17, and a camshaft. 16, a rocker shaft 19 fixed to the support block 12 having an axis parallel to the rocker arm 16, and a rocker arm 20 slidably supported by the rocker shaft 19 and slidably contacting the cam 15 and the cam driven piston 18.
With. The second cylinder body 17 has a bottomed cylinder hole 21 that opens downward, and a cam driven piston 18 is slidably fitted in the cylinder hole 21.
A hydraulic pressure generation chamber 22 is defined between the cylinder body 17 and the cam driven piston 18. The rocker arm 20 is swingably supported by the rocker shaft 19 at one end side thereof, and at the other end of the rocker arm 20, a roller 23 slidably contacting the cam 15 is pivotally supported and the cam driven piston 1
A projecting portion 24 that slidably contacts with 8 is provided.

In this hydraulic pressure generating means 9, the camshaft 1
The rocker arm 20 is driven by the cam 15 according to the rotation operation of
Is oscillated, whereby the cam driven piston 18 is reciprocally driven in the axial direction. Therefore, in the hydraulic pressure generation chamber 22, a hydraulic pressure according to the opening timing of the intake valve 6, that is, the cam profile of the cam 15 is generated.

An oil supply passage 25 communicating with the oil pressure generating chamber 22 is formed in the second cylinder body 17 and the support block 12, and a hydraulic circuit 26 is connected to the oil supply passage 25. The hydraulic circuit 26 controls a release timing of the hydraulic pressure from the hydraulic pressure generating chamber 22, that is, a lift amount and a closing timing of the intake valve 6, and the hydraulic release valve 2 as a hydraulic releasing means.
7, the accumulator 28, the one-way valve 29, and the replenishment check valve 30 are provided in the support block 12.

The hydraulic pressure release valve 27 is a normally-closed solenoid valve provided between the oil supply passage 25 and an oil passage 31 formed in the support block 12 while communicating with the accumulator 28.
The one-way valve 29 is arranged between the oil supply passage 25 and the oil passage 31 so as to bypass the oil pressure release valve 27 and is arranged in the support block 12, and the oil pressure of the oil passage 31 is set to be higher than that of the oil supply passage 25. Accumulator 2 opens when pressure exceeds
Only the working oil is allowed to flow from 8 to the oil supply passage 25.

The replenishment check valve 30 is operated from the oil pump 33 toward the oil passage 31 between the oil pump 33 and the oil passage 31 for pumping the working oil from the oil bath 32 provided in the cylinder head 1. It is arranged on the support block 12 so as to allow only the flow of oil.

Further, the oil supply passage 25 has a check valve 35 which allows only the flow of hydraulic oil toward the damper chamber 14 side.
And a throttling mechanism 36 that limits the amount of hydraulic oil flowing out from the damper chamber 14, and is connected to the damper chamber 14.

A recess 37 communicating with the oil supply passage 25 is provided on the outer surface of the first cylinder body 10, and an annular groove 38 communicating with the recess 37 is provided on the inner surface of the first cylinder body 10. Thus, the valve drive piston 11 is provided with a passage 39 communicating with the annular groove 38, and the check valve 3 is provided so as to allow only the flow of hydraulic oil from the passage 39 to the damper chamber 14.
5 is arranged on the valve drive piston 11. That is, the check valve 35 is fixed to the valve drive piston 11, and a retainer 41 that forms a valve chamber 40 that communicates with the valve drive piston 11 and communicates with the damper chamber 14, the passage 39, and the valve chamber 4.
A valve hole 4 formed in the valve drive piston 11 over a period of 0
2 and a spherical valve body 43 which is opened and closed in the valve chamber 40 and is accommodated in the valve chamber 40.

In the throttle mechanism 36, the throttle hole 44 formed in the first cylinder body 10 between the recess 37 and the damper chamber 14 and the intake valve 6, that is, the valve drive piston 11 are opened from the fully closed position by a predetermined amount. A variable throttle hole 45 provided in the valve drive piston 11 for communicating the damper chamber 14 with the annular groove 38 while gradually reducing the flow area when the valve is closed from the position actuated in the valve direction to the fully closed position.

According to such a check valve 35 and the throttle mechanism 36, in the operating region where the hydraulic pressure release valve 27 is kept closed, the hydraulic pressure generation means 9 generates the intake valve 6 in the fully closed state shown in FIG. The hydraulic pressure is supplied from the oil supply passage 25 to the recess 37,
It is guided to the damper chamber 14 through the annular groove 38, the check valve 35 and the throttle hole 44, and the hydraulic pressure in the damper chamber 14 pushes the valve drive piston 11 downward. Thus, during the sliding of the valve drive piston 11 downward, the oil supply passage 25
Directly communicates with the damper chamber 14 via the annular groove 38, whereby the amount of oil flowing into the damper chamber 14 becomes large, the valve drive piston 11 is pushed further downward, and the intake valve 6 is opened. ..

When the hydraulic pressure generated by the hydraulic pressure generating means 9 decreases after the intake valve 6 is fully opened, the intake valve 6 is driven upward by the spring force of the valve spring 7 in the valve closing direction.
By the closing operation of the intake valve 6, the valve drive piston 11 is also pushed upward, and the hydraulic oil in the damper chamber 14 is discharged to the oil supply passage 25. Thus, the direct communication state between the damper chamber 14 and the oil supply passage 25 is released during the closing operation of the intake valve 6,
The return amount of the hydraulic oil from the damper chamber 14 to the oil supply passage 25 is limited by the throttle mechanism 36. Therefore, the upward moving speed of the intake valve 6, that is, the valve closing speed is relaxed from the middle of the valve closing operation, and the intake valve 6 is gently seated, so that the impact at the time of seating is alleviated.

According to the present invention, the valve drive means 8 is provided with a damper chamber hydraulic pressure releasing means 46 capable of bypassing the throttle mechanism 36 and allowing the damper chamber 14 and the oil supply passage 25 to communicate with each other.
The damper chamber hydraulic pressure releasing means 46 is used for the valve drive piston 11
47 and the damper chamber 14 coaxially provided on the upper part of the
An on-off valve 48 provided therebetween, a check valve 49 provided between the recess 37 and the passage 47 communicating with the oil supply passage 25,
A drive mechanism 50 for driving the opening / closing valve 48 to open.

The open / close valve 48 has a spherical valve body 52 which can be seated on a valve seat 51 provided at an opening end of the passage 47 on the damper chamber 14 side. The spherical valve body 52 is fixed to the valve drive piston 11.
A spring 54 that is contracted between 3 and 3 biases the valve seat 51 in the direction in which it is seated.

The check valve 49 is arranged in the valve drive piston 11 so as to allow only the working oil from the passage 47 to flow into the recess 37, that is, the oil supply passage 25, and is opened in the passage 47. A valve seat 56 provided on the valve drive piston 11 having a valve hole 55 in the center, and the valve seat 5
6, a spherical valve element 57 that can be seated on the valve 6, and a valve drive piston 11
A retainer 58 fixed to the valve body 57 and a spring 59 compressed between the valve elements 57, and opens when the hydraulic pressure in the passage 47 becomes higher than the hydraulic pressure in the recess 37, that is, the oil supply passage 25 by a predetermined value or more. The hydraulic pressure of 47 is released to the oil supply passage 25 side.

The drive mechanism 50 is slidably supported by the guide cylinder 60, which is screwed to the upper end of the valve drive piston 11 so as to close the upper end of the passage 47 in an oil-tight manner. Drive pin 6 inserted coaxially in passage 47
1 and a cap 62 for preventing the leakage of hydraulic oil by slidingly contacting the outer surface of the drive pin 61 at the upper end of the guide cylinder 60.
Is installed.

Referring also to FIG. 3, the support block 12
A rotating shaft 63 extending in the arrangement direction of the drive pins 61 in each cylinder is rotatably supported by a bearing means 64 arranged in the support block 12, and corresponds to each drive pin 61. Arms 65 fixed to the rotating shaft 63 at the positions are connected to the upper ends of the drive pins 61. Moreover, a motor 66 fixedly supported by the support block 12 is connected to one end of the rotating shaft 63. Therefore, the rotation of the rotation shaft 63 by the operation of the motor 66 causes all the drive pins 61 to move.
Will be driven simultaneously.

Moreover, the motor 66 has the drive pin 61 shown in FIG.
4 and the lower position shown in FIG. 4 operate so as to drive up and down. In the state of FIG. 2, the on-off valve 48 is closed, but as shown in FIG. 6
When 1 is lowered to the lower position, the valve body 52 of the opening / closing valve 48 is forcibly separated from the valve seat 51, the opening / closing valve 48 opens, and the damper chamber 14 communicates with the passage 47.

Referring again to FIG. 1, the opening / closing operation of the hydraulic pressure release valve 27 and the operation of the motor 66 are controlled by the control means 67, which controls the engine speed N.
An engine speed detector 68 for detecting _E , an engine temperature detector 69 for detecting the engine temperature T _O , and an engine intake pressure P _B are respectively connected as operating state detecting means, and
An operation state detecting means 71 for detecting whether or not the damper chamber hydraulic pressure releasing means 46 is in a state where the opening / closing valve 48 is opened is connected to the control means 67. The operating state detecting means 71 is, for example, an encoder that detects the rotating position of the rotating shaft 63.

Thus, the control means 67 determines whether the engine speed N _E detected by the engine speed detector 68 is a predetermined value or more, or the engine temperature T _O detected by the engine temperature detector 69. Is a predetermined value or less and the intake valve 6 is operated at full lift, that is, in the operation region in which the hydraulic pressure release valve 27 is kept closed, the damper chamber hydraulic pressure is released in order to invalidate the throttle action of the throttle mechanism 36. Open / close valve 48 of means 46
The operation of the motor 66 is controlled so as to open the valve, and the opening / closing valve 48 is opened for some reason in the operating region where the closing timing and the lift amount of the intake valve 6 should be controlled by the hydraulic pressure release valve 27. When the operating state detecting means 71 detects that the hydraulic release valve 27 remains as it is, the opening operation of the hydraulic release valve 27 is prohibited at least at a time corresponding to the opening period of the intake valve 6, or the hydraulic release valve 27 is operated in the engine. Keep the valve open throughout the entire process.

The operation of this embodiment will now be described. When the engine temperature T _O is below a predetermined value and the viscosity of hydraulic oil is above a predetermined value, or when the engine speed N _E
Is equal to or greater than a predetermined value and the intake valve 6 should be operated at full lift, the motor 66 operates and the opening / closing valve 48 of the damper chamber hydraulic pressure releasing means 46 is opened as shown in FIG. Will remain. In this state, the hydraulic pressure generation means 9 generates hydraulic pressure corresponding to the opening timing of the intake valve 6 in response to the rotational operation of the cam 15, and the hydraulic pressure acts on the damper chamber 14 from the oil supply passage 25, thereby The drive piston 11 is pushed downward, and thereby the intake valve 6 is driven to open.

When the hydraulic pressure generated by the hydraulic pressure generating means 9 decreases after the intake valve 6 is fully opened, the intake valve 6 is driven upward by the spring force of the valve spring 7, that is, in the closing direction.
Due to the closing operation of the intake valve 6, the valve drive piston 11 is also pushed upward, and the oil in the damper chamber 14 is returned from the opening / closing valve 48 to the oil supply passage 25 via the check valve 49. The diaphragm action is not exhibited. Therefore, in the full lift operation of the intake valve 6 when the engine is rotating at high speed or when the hydraulic oil has a high viscosity, the adverse effect of the substantial change of the throttle degree of the throttle mechanism 36, that is, the throttle degree becomes substantially large. Even in the compression stroke of the engine, combustion failure due to the intake valve 6 not being completely seated is prevented, and the intake valve 6 is seated according to the cam profile of the cam 15.

Further, in the operating region in which the opening control of the hydraulic pressure release valve 27 should be executed to control the closing timing and the lift amount of the intake valve 6, as shown in FIG. The on-off valve 48 is closed. In this state, the return amount of the hydraulic oil from the damper chamber 14 to the oil supply passage 25 is limited by the throttle mechanism 36 during the closing operation of the intake valve 6, and the upward moving speed of the intake valve 6, that is, the closing speed. The intake valve 6 is loosened from the middle of the valve closing operation, and the intake valve 6 is gently seated, so that the impact at the time of seating is relaxed.

Further, in the operating region in which the opening control of the hydraulic pressure release valve 27 should be executed in order to control the closing timing and the lift amount of the intake valve 6, the operation of the damper chamber hydraulic pressure releasing means 46 is malfunctioning, When the operating state detecting means 71 detects that the on-off valve 48 remains open, the hydraulic pressure release valve 27 is at least at a time corresponding to the opening period of the intake valve 6.
The valve opening operation is prohibited, or the hydraulic pressure release valve 27 is held in the opened state during the entire stroke of the engine. Thus, by prohibiting the opening operation of the hydraulic pressure release valve 27 at the timing corresponding to the opening period of the intake valve 6, the intake valve 6 responds to the hydraulic pressure change of the hydraulic pressure generating means 9, that is, the cam profile of the cam 15. Due to the operating characteristic, the valve is closed, and it is possible to prevent the impact at the time of sitting from increasing even though the throttling action of the throttling mechanism 36 is disabled. Further, if the hydraulic pressure release valve 27 is held in the open state during the entire stroke of the engine, the intake valve 6 will be held in the closed state, and the engine will be substantially stopped. Although the throttle action is disabled, the impact of the intake valve 6 when seated does not increase.

FIG. 5 shows another embodiment of the present invention, in which parts corresponding to those in the above embodiment are designated by the same reference numerals.

The valve drive means 8 is provided with a damper chamber hydraulic pressure releasing means 46 'capable of bypassing the throttle mechanism 36 and allowing the damper chamber 14 and the oil supply passage 25 to communicate with each other, and this damper chamber hydraulic pressure releasing means 46'. The check valve 35 'is provided between the damper chamber 14 and the passage 47 provided coaxially in the upper portion of the valve drive piston 11, and the drive mechanism 50 for forcibly driving the check valve 35' to open. Prepare

The check valve 35 'has the same structure as the on-off valve 48 of the above embodiment, and is a spherical valve which can be seated on the valve seat 51 provided at the opening edge of the passage 47 on the damper chamber 14 side. The body 52 is biased in a direction to be seated on the valve seat 51 by a spring 54 that is compressed between the body 52 and a retainer 53 fixed to the valve drive piston 11. This check valve 35 '
Is in a state in which the drive pin 61 of the drive mechanism 50 is at the upper position, and is connected to the damper chamber 14 from the passage 47 communicating with the oil supply passage 25.
Although it allows the working oil to flow inward, but prevents the working oil from flowing from the damper chamber 14 to the passage 47 side, the drive pin 61 of the drive mechanism 50 pushes the valve body 52 downward. As a result, the valve will be forced to open.

In this embodiment, too, the check valve 35 'is forcibly opened by the drive mechanism 50 so that the throttle mechanism 3 is opened.
The diaphragm action of No. 6 can be invalidated, and the same effect as that of the above embodiment can be obtained.

In the above embodiment, the plurality of drive mechanisms 50 are operated by the motor 66 at the same time, but each drive mechanism 50 may be operated individually. In that case, the drive pin 61 is driven by a solenoid. You may do so.

The present invention can also be applied to an exhaust valve as an engine valve.

[0042]

As described above, the device according to the first aspect of the present invention detects the operating state of the engine, and the damper chamber hydraulic pressure releasing means that allows the damper chamber and the oil supply passage to communicate with each other by bypassing the throttle mechanism. An operating state detecting means and a control means for controlling the damper chamber hydraulic pressure releasing means in a communicating state so as to invalidate the throttling action of the throttling mechanism in response to the operating state detecting means detecting that the engine is in a predetermined operating state. Therefore, when the throttling action of the throttling mechanism adversely affects the operation of the engine,
The throttle action of the throttle mechanism is invalidated, and seating speed control suitable for the engine operating condition becomes possible.

In addition to the configuration of the first feature, the device according to the second feature of the present invention is such that the damper chamber hydraulic pressure release means bypasses the throttle mechanism and communicates between the damper chamber and the oil supply passage. Since the operating state detection means for detecting whether or not the throttle mechanism is provided is provided, it is possible to perform control in response to a state in which the throttle action of the throttle mechanism is invalid in an operating region where the throttle action of the throttle mechanism is required.

According to the third aspect of the present invention, in addition to the configuration of the second aspect, the control means can execute the operation control of the hydraulic pressure releasing means according to the operating state of the engine, and the damper. When the operation state detecting means detects that the room hydraulic pressure releasing means is in the communicating state, the hydraulic pressure releasing means is configured to prohibit the hydraulic pressure releasing operation at least when the engine valve is in the valve opening period. In the state where the throttle action of the throttle mechanism is disabled when the closing timing and the lift amount of the engine valve should be controlled, the engine valve is closed with the operating characteristic according to the change in the hydraulic pressure of the hydraulic pressure generating means. It is possible to prevent a large impact when seated.

Further, according to the fourth feature of the present invention, in addition to the configuration of the above-mentioned second feature, the control means can execute the operation control of the hydraulic pressure releasing means according to the operating state of the engine, and When the operating state detecting means detects that the damper chamber hydraulic releasing means is in the communicating state in the operating region of the engine where the hydraulic releasing means should perform the hydraulic releasing operation, the hydraulic releasing operation of the hydraulic releasing means is maintained in the entire stroke of the engine. Since the engine is substantially stopped, the impact when the engine valve is seated does not increase even if the throttle action of the throttle mechanism is disabled.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an engine according to an embodiment.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a plan view taken along arrow 3 of FIG.

FIG. 4 is a sectional view corresponding to FIG. 2 in a state where the hydraulic pressure in the damper chamber is released.

FIG. 5 is a sectional view corresponding to FIG. 2 of another embodiment.

[Explanation of symbols]

6 Intake valve as an engine valve 9 Hydraulic pressure generating means 10 Cylinder body 11 Valve driving piston 14 Damper chamber 25 Oil supply passage 27 Hydraulic release valve as hydraulic release means 35, 35 'Check valve 36 Throttle mechanism 46, 46' Hydraulic release of damper chamber Means 67 Control means 68 Engine speed detector as operating state detecting means 69 Engine temperature detector as operating state detecting means 70 Intake pressure detector 71 as operating state detecting means 71 Operating state detecting means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Eizo Kaiyama 1-4-1 Chuo, Wako-shi, Saitama, Ltd. Inside Honda R & D Co., Ltd.

Claims (4)

[Claims] 1. An engine valve (6) which is spring-biased in a valve closing direction.
A valve drive piston (11) whose one end is interlocked with and connected to is slidably fitted to the cylinder body (10), and is formed between the other end of the valve drive piston (11) and the cylinder body (10). In the chamber (14), a hydraulic pressure generating means (9) for generating a hydraulic pressure corresponding to the opening timing of the engine valve (6), and a hydraulic pressure releasing means (27) capable of releasing the hydraulic pressure according to the operating state of the engine. The oil supply passage (25) connected to the damper chamber (14)
Check valve (3 that allows only the inflow of hydraulic oil toward
5, 35 ') and a throttle mechanism (36) for limiting the outflow amount of hydraulic oil from the damper chamber (14), the throttle mechanism (36) is bypassed in the valve train of the internal combustion engine. Damper chamber hydraulic pressure releasing means (46, 46 ') capable of communicating between the damper chamber (14) and the oil supply passage (25), and operating state detecting means (68, 69, 7) for detecting the operating state of the engine.
0) and the operating state detecting means (68, 69, 70) detecting that the engine is in a predetermined operating state, the damper chamber hydraulic pressure releasing means for canceling the throttling action of the throttling mechanism (36). A valve operating system for an internal combustion engine, comprising: a control means (67) for controlling (46, 46 ') in a communication state. 2. A damper chamber hydraulic pressure releasing means (46, 46 ')
7. An operating condition detecting means (71) for detecting whether or not the bypass mechanism (36) bypasses the throttle mechanism (36) and the damper chamber (14) and the oil supply passage (25) are in communication with each other. 1. A valve operating system for an internal combustion engine according to 1. 3. The control means (67) can execute operation control of the hydraulic pressure releasing means (27) according to the operating state of the engine, and the damper chamber hydraulic pressure releasing means (46, 4).
6 ') is in communication with the operating state detecting means (7
3. The hydraulic pressure releasing operation of the hydraulic pressure releasing means (27) is prohibited at least at the time corresponding to the opening period of the engine valve (6) in the state detected by 1). Valve drive for internal combustion engine. 4. The engine capable of executing the operation control of the hydraulic pressure releasing means (27) according to the operating state of the engine, and the hydraulic pressure releasing means (27) should perform the hydraulic pressure releasing operation. In the operating area of the damper chamber hydraulic pressure releasing means (4
6, 46 ') are in communication with each other when the operating state detecting means (71) detects the hydraulic pressure releasing operation of the hydraulic pressure releasing means (27) during the entire stroke of the engine. The valve operating system for an internal combustion engine according to claim 2.