JPH0472969B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for stopping the supply and exhaust valves of an internal combustion engine at a predetermined time, and in particular to a valve stopping device capable of cutting valve operating force between a cam and a camshaft in a valve train. .

A vehicle equipped with an internal combustion engine does not require a large amount of power when driving under a light load, such as when driving steadily on a flat road, driving at low speeds in a city area, or when revving. In such a case, the internal combustion engine only needs to ignite the minimum amount of fuel necessary to continue its operation, and both the amount of air supply and fuel can be kept low. In particular, in the case of a two-valve internal combustion engine that has two intake valves and two exhaust valves, at low output, one Operate only the exhaust valve,
A system is known in which all four valves are operated at high output. Furthermore, in the case of a multi-cylinder engine, as disclosed in ``Automotive Engineering, April 1983 issue, New Mechanism Explanation'', the locking arms of some of the cylinders are oscillated to completely open the valves. It is also known that the cylinder is kept closed, stops output generation, and performs a cylinder deactivation operation under light load to maintain constant drive. All of these internal combustion engines can reduce wasteful fuel consumption, but they require a valve stop device to be installed in the valve train, making the valve train more complex than a normal internal combustion engine. This increases the mass of the driving part of the system, resulting in an increase in inertia.

SUMMARY OF THE INVENTION An object of the present invention is to provide a valve stop device that can suppress an increase in the mass of a valve train and more reliably switch between valve stop and valve operation.

A valve stop device according to the present invention includes a camshaft in a valve train of an internal combustion engine, a cam that fits externally on the camshaft, and a guide hole formed in the camshaft. It has a plunger that can enter and withdraw from the locking hole, and a hydraulic operating device that moves the plunger out of the locking hole when the valve is stopped. It is characterized by the formation of an oil bunkering path that can face the hole.

The present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a valve stop device 1 as an embodiment of the present invention. This valve stop device is installed on one cylinder of a multi-cylinder gasoline engine (not shown) that performs normal operation and cylinder deactivation operation in a timely manner (only one cylinder is shown here, but it can be installed on multiple cylinders in the same way). Installed. The valve train of this engine has a camshaft 2, which rotates at half the engine speed, pivotally mounted on a cylinder head 3, and a valve train for the intake valve installed parallel to the camshaft 2. An overhead valve structure is used in which the air supply valve (not shown) and the exhaust valve 7 are operated through the rocker arm 6 attached to the rocker arm shaft 4 (see Fig. 2) and the rocker arm shaft 5 for exhaust valve. present. Here, the valve stop device 1 operates the air supply valve and the exhaust valve 7 in the same way during the cylinder shutdown operation,
Since their structures are similar, the valve train system on the exhaust valve 7 side will be mainly explained hereafter.

The camshaft 2 is attached to a mounting base 8 on the cylinder head 3 via a bearing 10 integral with the camshaft 2, and a camcap 9 is attached to the mounting base 8 on the cylinder head 3.
It can be installed by bolting. The cam cap 9 works together with a plurality of other cam caps and mounting bases (not shown), and the cam shaft 2
In addition to the two Rotsuka armshafts 4 and 5 mentioned above.
(See Figure 2). Furthermore, oil passages 11 are formed in the cam cap 9 facing upward and downward.
A hydraulic operating device OC is connected to this. Oil road 11
The lower end opens into the annular groove 101 of the bearing part 10, and the upper end connects the oil control valve 1 through the oil pipe 12.
Connected to 3. oil control valve 13
is a three-way solenoid valve, which is operated by an output signal from a controller 14 consisting of a microcomputer. During normal valve operation, oil from the oil pump 15 is stored in an accumulator 151 serving as an oil reservoir, and the oil is supplied to the inlet port 131. When the valve is stopped, a switching operation is performed to guide the oil to the oil pipe 12 side through the operation port 132. Note that the reference numeral 133 indicates a drain port. On the other hand, the shaft oil passage 2 in the camshaft 2 is inserted into the bearing part 10 from a part of the annular groove 101.
A connecting path 102 communicating with 01 is formed. Therefore, when the bearing portion 10 integrated with the camshaft rotates around the center line l of the camshaft 2, the in-shaft oil passage 201 always
communicates with the oil pipe 12 via the annular groove 101 and the oil passage 11.

A cam for an air supply valve and a cam 16 for an exhaust valve (not shown) are respectively fitted to predetermined positions on the camshaft 2 at predetermined intervals. The annular inner wall surface 161 of the cam 16 is formed such that the center line of its base circle a (see FIG. 3) coincides with the center line l of the cam shaft 2. This annular inner wall surface has a truncated conical locking hole 1.
63 is formed. In addition, in order to prevent the cam 16 from shifting in the direction of its center line l, both sides 162 of the cam 16 are
It is formed flat and can slide into a notched circular stopper pin 17 that is irremovably attached to the camshaft 2. The camshaft 2 is provided with a sliding wall surface 202 located between the pair of stopper pins 17 and capable of sliding against the annular inner wall surface 161 of the cam. A guide hole 18 having a center line l1 orthogonal to the center line l is formed in the camshaft 2 surrounded by the sliding wall surface 202. The center part of the guide hole 18 is connected to the shaft oil passage 2.
01 in a crosswise manner, one end is open to the sliding wall surface 202, and the other end is opened to the narrow passage 202.
It faces a bottom wall 205 with 4. Note that the narrow passage 204 releases oil and air to the atmosphere through the relief groove 203 on the sliding wall surface 202. A plunger 19 as a locking member is slidably fitted into the guide hole 18 . As shown in FIG. 3, the entire length of this plunger 19 is slightly shorter than the length of the guide hole 18, and a hydraulic pressure receiving surface 191 is formed in the center thereof, and the other part of this hydraulic pressure receiving surface 191 is cylindrical. formed into a shape. Moreover, the lower side of the partition wall 192 forming the hydraulic pressure receiving surface 191, that is, the bottom wall 205 side is formed as a piston part 193, and this piston part 1
93 is urged away from the bottom wall 205 by the spring 21. A projecting part 194 is formed above the piston part 193, that is, on the opening side, and the projecting end thereof has a truncated conical shape that can be inserted into the locking hole 163. Note that a notch hole 195 is formed in the side wall of the protruding portion 194, through which the hydraulic pressure from the shaft oil passage 201 is transmitted to the hydraulic pressure receiving surface 191. In this way, the plunger 19 is biased so that its protruding portion 194 always protrudes from the guide hole by the elastic force of the spring 21 and plunges into the locking hole 163, and when receiving hydraulic pressure, the protruding portion 194 is pushed into the guide hole The structure is such that the person can be evacuated within the day.

The camshaft 2 includes the centerline l1 of the guide hole 18 into which the plunger 19 is fitted, and also forms three bunkering passages 23 on a surface perpendicular to the centerline l of the camshaft (see Fig. 3). ). That is, each auxiliary oil passage 23 extends radially from the shaft oil passage 201 and extends from the annular inner wall surface 1.
It has a shape with the open end facing 61.

Further, as shown in FIG. 3, a ramp groove 24 is formed in the annular inner wall surface 161 of the cam and has a shape that gradually increases in depth toward the locking hole 163. The ramp groove is formed in such a depth that the tip of the protruding portion 194 of the plunger can be inserted thereinto, and is formed in the inner peripheral direction of the annular inner wall surface 161 so that it can also face the opening ends of the three bunkering passages 23. formed for a long time.

Reference numeral 22 in FIG. 1 indicates a stopper post that restricts the range of the in-shaft oil passage 201.

The valve stop device 1 shown in FIG. 1 operates together with the operation of the engine. First, the controller 14 detects the engine rotation speed, engine load, transmission gear position, clutch on/off, etc. as the driving state of the vehicle, and determines whether the vehicle is running under a light load or when the engine is racing. The output signal is outputted to the oil control valve 13 only at the time, and the output signal is stopped at other times. That is, when the output signal is stopped, the oil control valve 13 is in the home position, and the pressure oil is supplied to the inflow port 131.
It is not transmitted to the oil pressure receiving surface 191 on the in-shaft oil passage 201 side. Therefore, the plunger 19 receives only the elastic force of the spring 21, and its protruding portion 194 can be thrust into the locking hole 163 of the cam, and the cam 16 rotates integrally with the camshaft 2, and the exhaust valve 7 Open and close under normal conditions. Note that the air supply valves (not shown) also operate normally, and the cylinders equipped with these valves generate output. On the other hand, when the controller 14 issues an output signal, the oil control valve 13 is switched to guide pressure oil to the operating port 132 (indicated by a dashed line in FIG. 1), and this oil pressure causes the oil pressure receiving surface 191 to
is pressed, the plunger 19 completely retreats into the guide hole 18 against the elastic force of the spring 21, and the cam shaft 2 rotates idly relative to the cam 16. Therefore, the exhaust valve 7 is maintained in a fully closed state. Similarly, the air supply valve (not shown) is also kept fully closed, so
The cylinder equipped with these two valves enters a cylinder deactivation operation in which output generation is stopped. Note that when the controller 14 stops the output again, the plunger 19 receives only the elastic force of the spring 21 again, and when its protrusion 194 faces the locking hole 163 of the cam, it plunges into it and engages the cam 16 and the camshaft. 2 rotates integrally, and the cylinder again enters normal operation capable of generating output.

In the above-mentioned sliding of the plunger 19, when the cylinder is not operated, the plunger 19 is completely retracted into the guide hole 18 due to high oil pressure, and the cam shaft 2 is moved against the cam 16, as shown in FIGS. 4 and 5. spins idly. Here, assuming that there is no bunkering passage 23,
The relief groove 203 on the camshaft 2 is long in the direction of the center line l of the camshaft, and faces the cam 16 every time it rotates once relative to the cam 16 (as shown in FIG. 4). Locking hole 163
When the lamp groove 24 and the ramp groove 24 are opened to the atmosphere, the oil in those parts is discharged, and when the plunger 19 faces the lamp groove 24 and the locking hole 163, the plunger 1
9 protrudes and temporarily enters the locking hole 163, causing the inconvenience of applying rotational force to the cam 16.
However, the three auxiliary oil passages 23 each receive high-pressure oil from the shaft oil passage 201, and their open ends are connected to the ramp groove 24 and the locking hole 1, as shown in FIG.
Oil can be filled while the plunger 19 faces the locking hole 163, and even if the plunger 19 faces the locking hole 163 or the like thereafter, its protrusion operation can be prevented, and the camshaft 2 can rotate smoothly.

Further, when the cylinder shut-off operation is changed to normal operation, the plunger 19, which had been retracted into the guide hole 18, is only subjected to the elastic force of the spring 21 due to the drop in oil pressure. When the tip of the protrusion 194 faces the lamp groove 24, the protrusion operation begins, and when the protrusion into the locking hole 163 is completed smoothly, the cam 16 and the camshaft 2 rotate integrally.

In this way, by operating the valve stop device 1 at a predetermined time, the cylinder to which the valve stop device 1 is attached can perform normal operation and cylinder-deactivation operation, and fuel consumption can be kept low. In particular, plunger 1
9 into the locking hole 163 is carried out smoothly due to the action of the ramp groove 24, and malfunction due to oil discharge from the ramp groove 24 or the locking hole 163 is prevented by the oil filling action of the auxiliary oil passage 23. This has the advantage that switching between valve stop and valve operation can be performed more reliably.

In the above-mentioned place, although three bunkering passages 23 are formed, there may be one, and the present invention is not limited to this.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a main part of a valve stop device as an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line X-X in FIG. 1, and FIG. 3 is a cross-sectional view taken along the Y-Y line in FIG. , FIG. 4, and FIG. 5 respectively show cross-sectional views when the relative positions of the cam and the camshaft used in the valve stop device are different. 1... Valve stop device, 2... Camshaft, 16... Cam, 18... Guide hole, 19... Plunger, 2
3... Oil bunkering path, 24... Lamp groove, 161... Annular inner wall surface, 163... Locking hole, 191... Hydraulic pressure receiving surface, OC... Hydraulic operating device.

Claims (1)

[Claims] 1. A cam shaft in a valve train of an internal combustion engine, a cam that is slidably fitted onto the cam shaft and has an annular inner wall surface, and a cam that is fitted into a guide hole formed in the cam shaft; and a plunger whose protruding portion can be inserted into and withdrawn from a locking hole formed on the annular inner wall surface, and an in-shaft oil passage formed on the camshaft when the valve is stopped, relative to the hydraulic pressure receiving surface formed in the center of the plunger. and a hydraulic operating device that applies hydraulic pressure through the camshaft to retract the plunger from the locking hole, and the camshaft has a auxiliary oil passage that extends from the in-shaft oil passage and whose open end can face the locking hole. Valve stop device with this configuration.