JPH09195739A - Valve stopper mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a swirl to be generated without increasing resistance of an intake passage, raise output of an engine including torque at slow speed, and improve emission and fuel consumption, by improving a valve system of the engine. SOLUTION: This valve stopper mechanism has a plurality of intake valves 7, each intake valve comprises a valve lifter 10 at the upper end of its valve stem 7a, and a cam 23 for drivingly pushing each valve lifter 10. For at least one intake valve, a slide member 12 engaging with its valve lifter is movably provided between the actuating position and stopping position in the perpendicular direction to its valve stem 7a, a spring 15 applying an elastic force to the slide member 12 in the axial direction of valve stem is provided. When the slide member 12 is in its actuating position, cam movement is transmitted to the valve stem 7a through the valve lifter 10, while in the stopping position of the slide member 12, a spring is interposed between the cam and the valve stem to retain the intake valve closed irrespective of the cam movement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve operating mechanism for an engine, and more particularly to a valve stopping mechanism for stopping valve operation on the intake valve side.

[0002]

2. Description of the Related Art A valve operating mechanism for driving an intake valve and an exhaust valve of an engine is equipped with a valve lifter at a valve shaft end portion of each valve installed in an intake port and an exhaust port of a cylinder head, and a crankshaft attached to the valve lifter. A cam that rotates in synchronism with is brought into contact with the cam, and the cam presses the valve shaft via the valve lifter to open / close the intake / exhaust valve according to the crank angle.

On the other hand, a lean-burn engine has been developed to improve fuel efficiency and emissions such as NOx. In this lean combustion, a swirl (vortex) is generated in the combustion chamber to stably burn the lean air-fuel mixture. We are trying to improve fuel efficiency. In addition, EG is used to improve emissions such as NOx.
An R type engine has been developed, and in this case also, it is desirable to generate a swirl in order to effectively burn the recirculated burned gas.

Conventionally, due to such swirl generation,
A swirl valve that opens and closes one side of the intake passage to deflect the air-fuel mixture sucked into the combustion chamber from the intake port to generate a vortex is provided in the intake passage.

A variable valve timing mechanism (VVT) is used to improve the low speed torque of the engine.
The output has been improved by controlling the phase of the rotation of the valve drive cam and the opening / closing operation of the valve that are interlocked with the rotating operation of the crankshaft to appropriately adjust the valve opening / closing timing corresponding to the crank angle.

[0006]

However, when the swirl valve in the lean burn system is used, the ventilation resistance of the intake passage increases, the intake efficiency decreases, and the performance deteriorates.

Further, even if the VVT is used to open and close the intake / exhaust valves at timings suitable for low speeds by opening and closing the valves, the opening time of each valve corresponding to the cam shape does not change. The so-called blow-through that was discharged was large, and it was not possible to sufficiently improve the torque particularly at low speed operation of 2000 rpm or less.

The present invention has been made in view of the above-mentioned drawbacks of the prior art. By improving the valve operating mechanism of the engine, swirl can be generated without increasing the resistance of the intake passage, and the engine including the low speed torque can be generated. It is an object of the present invention to provide a valve pause mechanism that can improve output and emission and fuel efficiency.

[0009]

To achieve the above object, in the present invention, a plurality of intake valves are provided, each intake valve is provided with a valve lifter at an upper end of a valve shaft, and a cam for pressing and driving each valve lifter is provided. In a valve deactivating mechanism for an internal combustion engine, a slide member that engages with a valve lifter of the at least one intake valve is provided so as to be movable between an operating position and a rest position in a direction perpendicular to the valve shaft, A spring for exerting an elastic force in the axial direction of the valve shaft is provided, the cam operation is transmitted to the valve shaft through the valve lifter in the operating position of the slide member, and the cam and the valve are operated in the rest position of the slide member. A valve pausing mechanism characterized in that the spring is interposed between the shafts to hold the intake valve in a closed state regardless of a cam operation. Subjected to.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a preferred embodiment,
The valve lifter has a spring receiving portion for supporting the spring in a central portion of an upper surface thereof, and a side wall protruding at a peripheral portion thereof, and a cam abuts on an upper surface of the slide member. Has a hanging wall at a position corresponding to the protruding side wall of the slide member, and in the operating position, the hanging wall of the slide member and the protruding side wall of the valve lifter contact each other to transmit a cam operation to the valve lifter, and in the rest position, the hanging wall is provided. It is characterized in that the wall and the side wall of the valve lifter are misaligned so that the cam operation is absorbed by the spring receiving portion.

In another preferred embodiment, the slide member is composed of a rigid main body portion and a spring portion adjacent to the rigid main body portion, a cam abuts on an upper surface of the valve lifter, and an intake valve of the intake valve is provided on an inner surface side of the valve lifter. The slide member is mounted on the valve shaft, the rigid body of the slide member contacts the valve shaft upper surface to transmit the cam operation to the valve shaft in the operating position, and the spring of the slide member in the rest position. The part is configured to move to the upper surface of the valve shaft and absorb the cam operation by a spring.

A further preferred embodiment is characterized in that a hydraulic drive mechanism is provided as a drive means for the slide member.

[0013]

1 (A) and 1 (B) are a plan view and a vertical sectional view, respectively, in a valve operating state of a valve deactivating mechanism according to an embodiment of the present invention, and FIGS. FIG. 3A is a plan view and a vertical cross-sectional view of the valve pause mechanism of FIG. 3 and 4 are configuration diagrams of the movable tappet and the valve lifter of this embodiment, respectively.

A combustion chamber 2 is formed below the cylinder head 1, and an intake passage 4 and an exhaust passage 5 communicate with the combustion chamber 2. A valve seat 3 is attached to an opening (intake port and exhaust port) of each of the intake and exhaust passages 4 and 5 to the combustion chamber 2, and an intake valve 7 and an exhaust valve 8 are attached thereto. 6 is a cooling water jacket.

A valve shaft 7a of the intake valve 7 has a valve guide 9
The valve lifter 10 is attached to the front end portion thereof. The valve lifter 10 and the valve shaft 7a together with the spring 1
Always biased upward by 1. This valve lifter 10
A projecting portion 10a is formed in the central portion of the upper surface, and a side wall 10b is projectingly formed in the peripheral edge portion (see FIG. 4). A movable tappet 12 is mounted on the valve lifter 10.
The movable tappet 12 is mounted in the tappet guide 16 and is slidable in a direction perpendicular to the valve shaft 17a between the valve operating position of FIG. 1 and the valve rest position of FIG. As shown in FIG. 3, the movable tappet 12, which is the sliding member, has hanging walls 12a at both longitudinal ends and side plates 12b on both side surfaces. The hanging wall 12a is formed at a position corresponding to the protruding side wall 10b of the valve lifter 10.
Then, the hanging wall 12a comes into contact with the upper surface of the protruding side wall 10b, and in FIG.

A sleeve 13 is mounted on the central protruding portion 10a of the valve lifter 10 and a spring 15 is housed therein. A sleeve 14 covers the sleeve 13. The sleeves 13 and 14 can slide relative to each other according to the expansion and contraction of the spring 15.

A valve driving cam 23 is provided on the upper surface of the movable tappet 12a. The cam 23 rotates via a chain or the like in synchronization with a crank shaft (not shown) to open and close the valve in accordance with the crank angle.

In the tappet guide 16, two hydraulic pistons 17 and 18 for driving the movable tappet 12 in opposite directions are provided. These hydraulic pistons 17, 18
A pump 21 supplies oil to the oil via an oil pipe (passage) 19. Control valves 20 ', 20 and pressure release valves 20a', 20a are provided on the oil pipes 19 on the upstream and downstream sides of the pistons 17, 18, respectively. Each control valve and pressure relief valve
Opening and closing is controlled by an ECU (engine control unit) 22 according to the engine speed and the throttle opening.

In the valve mechanism having the above structure, during normal operation, the movable tappet 12 is arranged at the valve operating position shown in FIG. 1, and the hanging wall 12a of the movable tappet 12 contacts the upper surface of the protruding side wall 10b of the valve lifter 10. Leave it in the ready state. Therefore, the rotational movement of the cam 23 causes the movable tappet 12 to move.
To the valve lifter 10 to move the valve shaft 7a up and down to open and close the intake valve 7 at a predetermined timing corresponding to the cam.

On the other hand, when it is desired to stop the valve operation, the control valve 20 on the upstream side of one piston 18 on the hydraulic pipe 19 is opened, and the pressure release valve 20a on the downstream side is closed. As a result, the piston 18 is hydraulically driven to push out the movable tappet 12 as shown in FIG. 2, and slide it to the valve rest position where the hanging wall 12a and the protruding side wall 10b of the valve lifter 10 are disengaged. In this state, the cam 23 rotates and the movable tappet 1
Even if 2 is pressed, the movable tappet 12 does not transmit this pressing force to the valve lifter 10. In this case, the intake valve 7 remains in the closed position in which it is raised by the spring 11 together with the valve lifter 10, and the movable tappet 12 is kept.
Moves up and down according to the cam 23 against the spring 15 on the valve lifter 10, so that the operation of the cam 23 is absorbed by the spring 15. As a result, it is possible to obtain an operating state (valve rest operating state) in which the intake valve is closed while the engine (crankshaft) is rotating.

To return from this state to the valve operating position of FIG. 1, the control valve 20 of the piston 18 is closed and the pressure release valve 20a is opened, and the control valve 20 'of the piston 17 is opened and the pressure release valve 20a' is opened.
Close. As a result, the piston 17 is hydraulically driven to push back the movable tappet 12.

In the multi-valve engine having a plurality of intake valves, the above-described valve rest operation is performed for some of the intake valves, so that the air-fuel mixture supplied into the combustion chamber is biased by the remaining intake valves. A swirl can be formed in the combustion chamber.

For example, in a five-valve engine having three intake valves and two exhaust valves, in the case where three intake valves are arranged along the circumference on the side of the crankshaft in the direction of the intake port, one end portion The swirl can be generated by stopping the intake valve or by stopping the two intake valves at one end and the center.

Further, the swirl can be generated not only with the structure of three intake valves but also with the structure of two intake valves, and the fuel consumption can be improved by stopping one valve.

Further, in the low speed operation region, the low speed torque can be improved by suspending a part of the intake valves. In this case, one intake valve is operated in the low speed operation, two intake valves are operated in the medium speed operation, and three intake valves (all valves) are operated in the high speed operation. The operating torque can be obtained, and therefore the torque can be improved in the entire range from low speed to high speed. In this case, the torque can be more effectively improved by controlling the valve drive in combination with the VVT.

5 and 6 are block diagrams of another embodiment of the present invention. FIG. 5 shows a valve operating state, and FIG. 6 shows a valve resting state. Further, FIG. 7 is an explanatory diagram of the configuration of the valve lifter of this embodiment.

In this embodiment, the cam 23 is in contact with the upper surface of the valve lifter 30 and the piston type slide member 31 is mounted in the valve lifter 30. An oil chamber 32 is formed on the front surface of the slide member 31, and an oil pipe (passage) 19 is connected through a communication port 33 formed in the valve lifter 30. A control valve 20 and a pressure release valve 20a are provided on the upstream side and the downstream side of the slide member 31 in the oil passage 19 (only the control valve 20 is shown in the figure). The slide member 31 includes a main body 31a made of a rigid body and a main body 31a.
A spring 35 provided on the back surface of a and having elasticity in the valve axis direction, and a spring 3 having elasticity in the direction perpendicular to the valve axis.
4 and the spring 35 is supported on a pedestal 36.

In the valve mechanism having the above structure, the communication port 33 is provided in a state where the base circle of the cam 23 is in contact with the upper surface of the valve lifter 30 (when the valve lifter 30 is raised).
Align with the oil passage 19. When the upstream control valve 20 is opened in this state, the oil is filled in the oil chamber 32. Due to this hydraulic pressure, the slide member 31 retracts against the spring 34, and the rigid main body 31a is positioned on the lift adjusting pad (shim) 37 at the tip of the valve shaft, as shown in FIG. This position is the valve operating position. When the cam 23 rotates in the valve operating position, the cam operation is performed from the upper surface of the valve lifter 30 to the slide member 31.
Is transmitted to the valve shaft 7a through the rigid body 31a of
a moves up and down to open and close the intake valve 7.

When shifting from the valve operating position (FIG. 5) to the valve rest position (FIG. 6), the slide member 31 is used.
The upstream side control valve 20 is closed and the downstream pressure release valve is opened. As a result, when the valve lifter 30 rises and the communication port 33 is aligned with the oil passage 19, the spring 34 pushes the slide member 31 forward, drains the oil in the oil chamber 32, and the rigidity of the slide member 31 increases. The main body 31a is removed from the position on the valve shaft, and the pedestal 36 of the spring 35 is positioned on the valve shaft. Even if the cam 23 rotates in this state to move the valve lifter 30 up and down, the vertical movement is absorbed by the spring 35 and is not transmitted to the valve shaft. Therefore, the valve 7 is kept closed. Other configurations and operational effects are similar to those of the embodiment shown in FIG.

[0030]

As described above, in the present invention, by using the hydraulically driven slide member, it is possible to easily and surely suspend some of the intake valves during engine operation according to the operating condition. It is possible to generate swirl without using a swirl valve or the like that becomes ventilation resistance. As a result, lean combustion or EGR operation can be performed with high efficiency, high-speed output can be improved, and fuel consumption and emission can be improved.

Further, the torque can be improved by the valve stop operation at the low speed, and the fuel consumption can be improved by performing the cylinder stop operation in the multi-cylinder engine. In addition, if the number of intake valves to be operated is increased to 1, 2, 3 from low speed operation to high speed operation in accordance with the operating state, the valve control with the maximum efficiency is achieved in the entire operating range, and in all the areas. The torque can be improved.

[Brief description of the drawings]

1A and 1B are a plan view and a vertical cross-sectional view, respectively, in a valve operating position of a valve mechanism according to an embodiment of the present invention.

2A and 2B are a plan view and a vertical sectional view, respectively, in a valve rest position of the embodiment of FIG.

3 (A), (B), and (C) are a side view, a horizontal sectional view, and a vertical sectional view of a movable tappet used in the embodiment of FIG.

4 (A), (B), and (C) are a top view, a side view, and a vertical cross-sectional view of a valve lifter used in the embodiment of FIG.

FIG. 5 is a configuration explanatory view of another embodiment of the present invention.

6 is a block diagram of the embodiment of FIG. 5 in a valve rest position.

7 (A) to (E) are a top view, a side view, a horizontal cross-sectional configuration view, a cross-sectional view taken in the direction of arrow (A), and a view taken in the direction of arrow (D) of the valve lifter used in the embodiment of FIG. 5, respectively. It is a cross-sectional block diagram.

[Explanation of symbols]

 7: intake valve 7a: valve shaft 10: valve lifter 12: movable tappet 12a: hanging wall 15: spring 16: tappet guide 17, 18: piston 19: oil pipe 20: control valve 20a: pressure release valve 23: cam

Claims (4)

[Claims] 1. A valve deactivation mechanism for an internal combustion engine having a plurality of intake valves, each intake valve having a valve lifter at an upper end of a valve shaft, and having a cam for pressing and driving each valve lifter, wherein at least one intake valve is provided. On the other hand, a slide member that engages with the valve lifter is provided so as to be movable between an operating position and a rest position in the direction perpendicular to the valve shaft, and a spring that applies an elastic force to the slide member in the axial direction of the valve shaft is provided. In the operating position of the slide member, the cam operation is transmitted to the valve shaft via the valve lifter, and in the rest position of the slide member, the spring is interposed between the cam and the valve shaft to allow intake regardless of the cam operation. A valve pause mechanism characterized in that the valve is configured to be held in a closed state. 2. The valve lifter has a spring receiving portion for supporting the spring in a central portion of an upper surface thereof, and a side wall protruding at a peripheral edge portion thereof, and a cam abuts on an upper surface of the slide member to allow the slide member to slide. The member has a hanging wall at a position corresponding to the protruding side wall of the valve lifter, and in the operating position, the hanging wall of the slide member and the protruding side wall of the valve lifter come into contact with each other to transmit a cam operation to the valve lifter, and thus the pause. 2. The valve pausing mechanism according to claim 1, wherein at the position, the hanging wall and the side wall of the valve lifter are displaced from each other so that the cam operation is absorbed by the spring receiving portion. 3. The slide member includes a rigid main body and a spring portion adjacent to the rigid main body, a cam contacts the upper surface of the valve lifter, and the slide member is provided on the valve shaft of the intake valve on the inner surface side of the valve lifter. In the operating position, the rigid main body of the slide member abuts the valve shaft upper surface to transmit the cam operation to the valve shaft, and in the rest position, the spring portion of the slide member moves to the valve shaft upper surface. The valve resting mechanism according to claim 1, wherein the valve resting mechanism is configured to move and absorb the cam action by a spring. 4. The valve pausing mechanism according to claim 1, wherein a hydraulic drive mechanism is provided as a drive means for the slide member.