JPH022446B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a variable cylinder device for an internal combustion engine, and more particularly to a variable cylinder device for an internal combustion engine in which a pressure-feeding hydraulic lifter is attached to a valve operating system.

There is a device that increases or decreases the number of operating cylinders depending on the engine operating condition. For example, when the engine load is low, the lift operation of the intake and exhaust valves is stopped and the number of operating cylinders is limited to improve fuel efficiency. Various proposals have been made. For example, a variable cylinder device disclosed in Japanese Patent Application Laid-Open No. 54-57009 uses hydraulic oil in a hydraulic lifter pressure chamber in an engine in which a hydraulic lifter is attached to a valve mechanism for operating intake and exhaust valves. It is provided with an oil discharge path for releasing oil and a shutoff valve that opens and closes the oil discharge path as necessary. However, in the above-mentioned conventional device using a hydraulic lifter, an oil discharge port is provided in the lifter body to release oil from the hydraulic lifter pressure chamber, and an oil discharge path communicating with the discharge port is provided in the cylinder block and an oil discharge port is provided for the shaft of the shutoff valve. Since the structure is such that the sliding holes are formed respectively, there are problems in that the machining work increases, the structure becomes complicated, and the manufacturing cost increases. In addition, a sealing mechanism is required for the oil discharge passage, and in particular, a sealing device is required for the communication portion between the oil discharge port and the oil discharge passage and the shaft sliding portion of the shutoff valve, which is disadvantageous in practice.

Accordingly, an object of the present invention is to simplify the structure and reduce manufacturing costs in a variable cylinder device in which a hydraulic lifter is attached to a valve operating system.

In order to achieve the object, the present invention includes:
a solenoid valve that operates by sensing an engine input signal; a shaft that presses a check ball of the pressure-feed hydraulic lifter in response to the operation of the solenoid valve; and a shaft fixed within the hydraulic lifter to guide the tip of the shaft. When the check ball is pressed, the pressure chamber of the hydraulic lift and the storage chamber are forced into communication and the rigidity of the hydraulic lifter is removed, thereby stopping the operation of the valve system, that is, opening and closing the intake and exhaust valves. It is configured to stop the operation.

Generally, the check ball of a hydraulic lifter is spherical, so if the tip of the solenoid valve becomes clogged and the tip of the hydraulic shaft shakes even a little, the check ball will not be pressed straight in the specified direction.
Therefore, system malfunctions may occur due to insufficient displacement of the check ball, that is, insufficient opening amount of the ball, or abnormalities such as wear may occur at the tip of the shaft.However, according to the configuration of the present invention, the shaft that presses the check ball A guide plate is fixed inside the hydraulic lifter to guide the tip of the
Problems such as malfunction can be resolved. In addition, when guiding a solenoid valve, it is necessary to reduce the dimensions of the shaft, which tends to cause malfunctions, but in the present invention, the structure is simple and easy, simply by adding a guide plate. This can be dealt with by

An embodiment embodying the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a partial sectional view showing a valve train system 10 for an internal combustion engine. In the figure, the inside of the cylinder 12 formed in the cylinder block 11 is shown as follows.
A piston (not shown) reciprocates up and down. Cylinder head 1 forming the upper end of cylinder 12
3, a combustion chamber 14 is formed above the piston. Communication between the combustion chamber 14 and the cylinder head port 15 is controlled to open or close by a valve 16. A valve stem 18 is slidably inserted into a valve guide 17 formed in the cylinder head 13. A valve spring 21 is stretched between a spring seat 19 formed at the upper end of the cylinder head 13 and a spring retainer 20 fixed to the upper end surface of the valve stem 18. Due to the load of the spring 21, the valve 16 is always urged upward in the figure so as to be seated on the valve seat 22. The rocker arm 23 has one end 23a connected to the top of the valve stem 18, and the other end 23a.
b is in contact with the cam surface 24a of the camshaft 24. Rotsuka arm 23 is Rotsuka support 25
The support 25 is fixed to the support 25 so as to be swingable around the fulcrum A of the support 25. camshaft 2
The rocker arm 23 performs a swinging motion due to the rotational movement of the valve 16, and as a result, the valve 16 repeats opening and closing operations.

Next, a lower part of a known pressure-feeding hydraulic lifter 30 is inserted and fixed into the hollow part of the rocker support 25. On the other hand, the upper part of the hydraulic lifter is slidably inserted into the lifter support 31. The lifter body 32 has a cylinder 33 with an open upper end formed therein, and a plunger 34 repeats reciprocating motion in the vertical direction inside the cylinder 33. The contents of the plunger 34 include the reservoir 3
5 is formed, and oil, which is pumped from, for example, an oil pump (not shown), is supplied into the reservoir 35 through an oil passage 36. The oil is supplied through passages 31a and 34b formed in the lifter support 31 and the support portion 34a of the plunger 34, respectively.

On the other hand, inside the cylinder 33 of the lifter body 32,
A pressure chamber 37 is formed by the lower end surface of the plunger 34 . An oil passage 38 is formed at the center of the bottom 34a of the plunger 34, and a well-known ball check valve 39 is disposed on the pressure chamber 37 side of the oil passage 38. The check valve 39 is connected to the reservoir 3.
5 to the pressure chamber 37, but has a function of blocking oil flow from the pressure chamber 37 to the reservoir 35 in the opposite direction. retainer 40
The check valve 39 is constantly biased in the closing direction by the other end of the spring 41, one end of which is supported by the other end. A plunger spring 42 having a strong load due to the spring 41 is disposed in the pressure chamber 37, and the plunger 34 is always urged upward with respect to the lifter body 32 by the spring 42. A snap spring 43 is fitted into the upper inner circumference of the lifter body 32.
This restricts upward movement of the plunger 34.
Leak clearance 44 formed between the inner peripheral surface of the lifter body 32 and the outer peripheral surface of the plunger 34
serves as a passage for leaking oil from the pressure chamber 37. The solenoid valve 50 mounted on the top surface of the cylinder head cover 26 is operated by a microcomputer (not shown), which senses engine input signals such as continuous speed, carburetor throttle opening, and engine temperature. The valve 50 is controlled and operated. A shaft (or valve stem) 51 of the solenoid valve 50 passes through the center of the upper end surface 31a of the lifter support 31, is disposed within the reservoir 35, and is slidable in the vertical direction. More specifically, the tip 51a of the shaft 51 is located above the plunger 34.
A guide plate 45 shown in FIG. 2 is fixed to guide the tip 5 of the shaft 51.
1a is a configuration in which the guide plate 45 is displaced within the shaft hole 46. The guide plate 45 has a plurality of through holes 47 on the inner circumference (four in the embodiment).
), the through hole 47 serves as an oil flow path to the reservoir 35. Now, solenoid valve 50
In response to the operation, the shaft 51 moves downward to press the pole check valve 39 downward;
As a result, the oil passage 38 opens and some of the oil in the pressure chamber 37 moves into the reservoir 35.

In the above configuration, the following operation will be explained. The above-mentioned hydraulic lifter 30 constantly repeats expansion and contraction movements in small dimensions (usually 2 to 3 mm) during engine operation to absorb clearance or thermal expansion that occurs in the valve train system, and to maintain the valve train at a constant size at all times. It operates as follows. A detailed explanation of this telescoping motion will be omitted here.

Now, when the engine load is light, the microcomputer senses engine input signals such as engine negative pressure, vehicle speed, throttle opening, etc., and operates the solenoid valve 50. In response to the operation of the valve 50, the shaft 51 moves downward to press the check valve 39 downward and open the oil passage 38.
open. At this time, the pressure chamber 37 and the reservoir 35 are communicated with each other, and the oil in the pressure chamber 37 can flow out into the reservoir 35.
When the hydraulic lifter 30 moves up and down, the lifter body 32 of the hydraulic lifter 30 moves upward relative to the lifter support 31. That is, since the rigidity of the hydraulic lifter 30 is removed, the rocker arm 23 repeats the rocking motion using the connecting portion B of the arm 23 with the valve stem 18 as a fulcrum. Therefore, even if the cam surface 24a reaches the upper end, the rocker arm 23 pivots about the point B, so the valve lift mechanism is stopped and the opening/closing operation of the valve 16 is prevented. In addition, the lifter support 31 of the lifter body 32
The amount of relative movement to is designed in consideration of the stroke amount of the intake and exhaust valves 16.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing a valve train system for an internal combustion engine in which the variable cylinder device of the present invention is installed, FIG. 2 is a sectional view of a guide plate in FIG. 1,
FIG. 3 is a plan view of the guide plate in FIG. 2. 10...Valve train system, 16...Intake and exhaust valve, 3
0...Pressure-feeding hydraulic lifter, 34...Plunger, 39
...Ball check valve, 45...Guide plate, 46...Shaft hole, 47...Through hole, 50...Solenoid valve, 51...Shaft (valve stem).

Claims (1)

[Claims] 1 In an internal combustion engine in which a pressure-feeding hydraulic lifter is installed in a valve operating system for operating intake and exhaust valves, a solenoid valve is operated by sensing an engine input signal, and the hydraulic pressure is increased in response to the operation of the solenoid valve. A press shaft for pressing a check ball of a lifter, and a guide plate fixed to a plunger in the hydraulic lifter for guiding the tip of the shaft, and the guide plate has a shaft hole in the center into which the shaft is loosely fitted. and a variable cylinder device for an internal combustion engine, having a plurality of through holes surrounding the shaft hole.