JPS62294709A - Valve operation control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To changeover intake and exhaust valve opening characteristics with a simple structure, by changing over the connection and nonconnection of two valve driving members for driving intake and exhaust valves by means of the cams for high-speed and low-speed use in response to the operating conditions of an engine. CONSTITUTION:The first valve driving member 15 which drives two intake valves 91 and 92 is rocked by a cam for low-speed use. Adjacent to the first valve driving member 15, the second valve driving member 16 is provided, and the second valve driving member 16 is rocked by a cam for high-speed use. At the time of high-speed revolution of an internal combustion engine, a connecting pin 24 is pressed out by the pressure oil led through oil passages 17b, 17a, and 26, and the first valve driving member 15 and the second valve driving member 16 are integrally rocked, and respective valves 91 and 92 are driven by the cam for high-speed use in which the lift curve of valve driving cam is higher than or nearly equal to that of the cam for low-speed use. At the time of low-speed revolution, oil pressure is released, and the pin 24 is pressed by a spring 30, and the connection of the first and the second valve driving members 15, 16 is released, so that respective valve 91 and 92 are driven by the cam for low-speed use. The same is the case with the exhaust valves.

Description

[Detailed description of the invention] 3. Detailed description of the invention (Industrial application field) The present invention relates to a valve EJJ control device for an internal combustion engine.

(Technical Background of the Invention) In general, some high-output internal combustion engines are of a type in which each cylinder is provided with two intake or exhaust valves having the same function. This type of internal combustion engine has a large area of communication passage between the intake passage or exhaust passage and the combustion chamber, which is opened and closed by two valves, so it can take in a large amount of air-fuel mixture or discharge a large amount of exhaust gas. Suitable for operating and operating internal combustion engines at high rotation and high output.

However, when the internal gear of this type [; Therefore, the charging efficiency further decreases, and since intake air blow-through generally occurs in the low rotation range, if the exhaust valve opening area is large, the charging efficiency decreases, and the output of the internal combustion engine decreases accordingly. .

In order to eliminate this problem, when the internal combustion engine is operating at low speeds, only one of the two valves is opened and closed, and the other valve is stopped from opening and closing, thereby reducing the communication path between the intake or exhaust passage and the combustion chamber. Generally, methods are used to narrow the area of the engine so that intake inertia can be used even during low-speed operation, or to reduce intake air blow-through.

(Prior Art and its Problems) A valve train for carrying out this method is known from Japanese Patent Application Laid-Open No. 57-188716.

In such a conventional device, a camshaft with a low-speed cam and a camshaft with a high-speed cam are supported in one holder, and a low-speed slipper that slides on the low-speed cam and a high-speed cam are attached to a single rocker arm. When the internal combustion engine rotates at low and high speeds, the holder is swung upwards so that only the low-speed camshaft slides into contact with the rocker arm, and when the internal combustion engine is rotated at high speeds, the holder is swung downwards. The structure is such that only the high-speed camshaft slides into contact with the rocker arm by moving the rocker arm.

Therefore, since the holder is configured to swing up and down together with the rocker arm, the structure is complicated, and rapid switching is not possible, making it unsuitable for high-speed internal combustion engines. Further, since a vertically swingable holder supporting the rocker arm and a box for accommodating the holder are required, there is a problem that the circumference of the cylinder head becomes large.

(Objective of the Invention) The present invention has been made in view of the above circumstances, and although it has a simple and compact structure, it is capable of obtaining high output over the entire rotation range from low speed to high speed of an internal combustion engine. An object of the present invention is to provide a valve actuation control device for an internal combustion engine that can perform the following functions.

(Means for Solving the Problems) In order to solve the above problems, the present invention has a plurality of cams with different profiles corresponding to a plurality of intake valves or exhaust valves provided for each cylinder, and a camshaft that is rotatably driven in synchronization with the rotation of the engine; a first valve driving member that drives the intake valve or the exhaust valve to open and close; and a second valve driving member that contacts another cam of the plurality of cams; A connection switching means is provided for selectively switching the members between a state in which they are integrally connected and a state in which they can be relatively displaced.

(Example) An example of the present invention will be described below based on the drawings. 1st
The figure is a partially omitted longitudinal cross-sectional view of a 4-cylinder 16-valve internal combustion engine. In this figure, a piston 4 is slidably fitted into a cylinder barrel 3 within a cylinder block 2 of an internal combustion engine 1. The cylinder head 5 mounted on the upper part of the cylinder block 2 is provided with an intake passage 7 and an exhaust passage 8 that communicate with the combustion chamber 6. Exhaust pipes (not shown) are connected to each. The communication portion (intake port) between the intake passage 7 and the combustion chamber 6 includes two intake valves 9 (only one shown) arranged in parallel with each other.
The communication part (exhaust port) between the exhaust passage 8 and the combustion chamber 6 is also provided by two exhaust valves 10 (1
(only one is shown).

These two intake valves 9 and exhaust valves 10 are opened and closed by valve operation control devices 1'l and 12, respectively.

Since the valve operation control device 11 for the intake valve 9 and the valve operation control device 12 for the exhaust valve 10 have the same configuration, only the valve operation control device 11 for the intake valve 9 will be explained below, and the valve operation control device 12 for the exhaust valve 10 will be explained below. Regarding the valve actuation control device 12, the same parts in the drawings are denoted by the same reference numerals, and the explanation thereof will be omitted.

The two intake valves 91 and 92 are fitted into the guide cylinder 13 and are biased by a spring 14 in a direction to close the communication portion between the intake passage 7 and the combustion chamber 6. At the upper ends of the two intake valves 91 and 92, each end 1 of a main rocker arm (first valve driving member) 15 is attached as shown in FIGS. 2 and 3.
5a and 15b are abuttingly engaged. This main rocker arm 15 is adjacent to a sub rocker arm (second valve driving member) 16, and its boss portions 15C and 16C are rotatably fitted onto a common rocker arm shaft 17. These main and sub rocker arms 15 and 16 have slippers 18 and 19, and the slipper 18 of the main rocker arm 15 is attached to the camshaft 20.
The slipper 19 of the sub-lofka arm 16 is in sliding contact with a high-speed cam 22 which is adjacent to the low-speed cam 21 and is integrally provided with the camshaft 20.

FIG. 4 is a cam profile curve diagram of the low-speed cam 21 and the high-speed cam 22, and as is clear from the figure, the lift curve of the high-speed cam 22 is always higher than or approximately the same as the lift curve of the low-speed cam 21. The settings are as follows. In addition,
The secondary rocker arm 16 does not engage the intake valve 91.92, and only the main rocker arm 15 engages the intake valve 91.92.
92. Further, the auxiliary rocker arm I6 is urged toward the high-speed cam 22 by a torsion spring 31.

The main rocker arm 15 and the auxiliary rocker arm 16 are selectively switched by a connection switching means 23 between a state where they are integrally connected, that is, an interlocking state, and a state where they can be relatively displaced, that is, a non-interlocking state.

The connection switching means 23 has a first pin (plunger) 24 having a piston function. The first nozzle 24 is fitted into a fitting hole (cylinder) 25 of the main rocker arm 15 so as to be slidable through a predetermined stroke. A hydraulic chamber 25a defined between the inner end surface of the first pin 24 and the inner end surface of the main rocker arm 15 includes an oil passage 26 inside the main rocker arm 15 and an oil passage hole 17a of the rocker arm shaft 17.
It is connected to a hydraulic pressure supply source (not shown) through an oil passage 17b, and when the internal combustion engine rotates at high speed, hydraulic pressure is automatically supplied into the hydraulic chamber 25a, and when the internal combustion engine rotates at low speed, the hydraulic pressure in the hydraulic chamber 25a is It is automatically released. The first pin 24 is urged toward the sub-rocker arm 16 by a spring 27 provided in the hydraulic chamber 25a. The outer end surface of the first pin 24 is connected to the fitting hole (cylinder) 2 of the sub rocker arm 16.
8, the second pin 2 is slidably fitted within the pin 8 for a predetermined stroke.
It is in contact with one end surface of 9. The second pin 29 is connected to the spring 3
0 biases the main rocker arm 15 side. Note that the biasing force of the spring 27 that biases the first pin 24 toward the auxiliary rocker arm 16 causes the second pin 29 to bias toward the main rocker arm 1.
The biasing force of the spring 30 is set to be smaller than that of the spring 30 biasing toward the 5th side.

Therefore, when hydraulic pressure is not supplied into the pressure chamber 25a, the contact surface between the first pin 24 and the second pin 29 is located at the boundary between both rocker arms 1'5. The lever arms 15, 16 become uncoupled.

(Function) Next, the function of the valve actuation control device 1 of the present invention having the above structure will be explained. When the internal combustion engine 1 rotates at high speed, the oil pressure flows through the oil passage 17.
b. The oil is supplied into the hydraulic chamber 25a through the oil hole 17a and the oil passage 26, and the oil pressure causes the first pin 24 and the second pin 29 to slide in one direction against the biasing force of the spring 30. The double-ended hook arms 15 and 16 are connected to each other via the first pin 24. As mentioned above, the lift curve of the high-speed cam 22 is always higher than or substantially the same as the lift curve of the low-speed cam 21, so the rotation of the high-speed cam 22 causes the sub-rocker arm to have the slide collar 19 in sliding contact with the cam 22. The main rocker arm 15 also rotates together with the main rocker arm 16, and both intake valves and discharge valves 92 open and close according to the high-speed cam 22. Although the low-speed cam 21 rotates, it is not involved in the opening and closing operations of the intake valves 9+ and 92. It's something you don't do.

When the internal combustion engine 1 rotates at a low speed from this state, the hydraulic pressure in the hydraulic chamber 25a is released as described above, so that the first pin 24 and the second pin 29 are moved in the other direction by the biasing force of the spring 30. rdJL, the contact surfaces of both pins 24.29 are located at the boundary between both rocker arms 15.16, and both locking arms 15.16 are in a non-interlocking state. Therefore,
The main rocker arm 15 having a slipper 18 in contact with the low-speed cam 21 rotates with the rotation of the low-speed cam 21, and both intake valves 91 and 92 open and close according to the low-speed cam 21, and the high-speed cam 22 The auxiliary rocker arm 16, which has a slipper 19 in sliding contact with the cam 22, rotates with the rotation of the high-speed cam 22, but does not participate in the opening/closing operation of the intake valves 9+, 92 at all.

The operation of the valve operation control device 12 of the exhaust valve 1 (h, 102 example) is the same as that of the valve operation control device 11 on the intake valve 91, 92 side described above.

(Effects of the Invention) As described in detail above, the valve actuation control device for an internal combustion engine of the present invention has a simple and compact structure, and has the same characteristics as shown in the horsepower characteristic diagram in FIG. Compared to the normal method, this method has the effect of being able to obtain high output over the entire rotation range of the internal combustion engine from low speed to high speed.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which FIG. 1 is a longitudinal cross-sectional view of the valve actuation control device for an internal combustion engine of the present invention, and FIG. 2 is a plan view thereof;
Fig. 3 is a partially cutaway plan view of the valve actuation control device of an example of an intake valve, Fig. 4 is a profile curve diagram of a high-speed cam and a low-speed cam, and Fig. 5 is a horsepower characteristic line between the conventional and the present invention. It is a diagram. 1...Internal combustion engine, 9,91.92...Intake valve, 10
゜1(h, 102...exhaust valve, 11.12...
Valve operation control device, 15... Main rocker arm (first valve drive member), 16... Sub rocker arm (second valve drive member), 20... Cam shaft, 21... Low speed cam ( 1 cam), 22...High-speed cam (other cam), 23...
...Connection switching means, 24...First pin (plunger), 25.28... Fitting hole (cylinder). Applicant Honda Motor Co., Ltd. Agent Patent Attorney Toshihiko Watanabe Motor rotation angle→ Figure 5 Temporary job/temporary rotation speed→

Claims (1)

[Claims] 1. A camshaft having a plurality of cams with different profiles corresponding to a plurality of intake valves or exhaust valves provided for each cylinder, and which is rotationally driven in synchronization with the rotation of the engine. , a first valve drive that contacts one cam of the plurality of cams and the plurality of intake valves or exhaust valves and drives the plurality of intake valves or exhaust valves to open or close in accordance with the rotational movement of the one cam; and a second valve drive member that abuts another cam of the plurality of cams, the first and second valve drive members comprising:
A valve operation control device for an internal combustion engine, comprising a connection switching means for selectively switching between an integrally connected state and a relatively displaceable state. 2. The connection switching means includes a cylinder that accommodates a plunger in the first and second valve drive members, and the plunger can move freely into and out of the cylinder of the other valve drive member from one valve drive member. A valve operation control device for an internal combustion engine according to claim 1, characterized in that it is configured as follows.