JPH0480203B2 - - 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. .

Vehicles equipped with internal combustion engines do not require a large amount of power when operating under light loads, such as when driving steadily on a flat road or at low speeds in urban areas, 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 multi-cylinder engines,
As disclosed in ``New Mechanism Explanation'', the locking arm of some of the cylinders is oscillated to keep the valve fully closed, stopping output generation, and cylinders are deactivated under light load. There are also known devices that perform this 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 mass of a valve train and has a simplified structure.

A valve stop device according to the present invention includes a camshaft in a valve train of an internal combustion engine, a cam that is slidably fitted onto the camshaft, a concave portion formed on a sliding surface of the cam, and a concave portion formed in the sliding surface of the cam. a guide portion formed on the camshaft so as to face the camshaft; a locking member slidably fitted into the guide portion; and a locking member formed on the locking member to be locked in the recessed portion. a protruding portion, a biasing means for urging the protruding portion in a direction in which the protruding portion is locked in the recessed portion, and a pressing force that presses the protruding portion against the recessed portion in a direction in which the locking is released. an operation surface formed on the locking member to receive the operation surface, an operation means that applies a pressing force in the unlocking direction to the operation surface, and a protrusion of the locking member that presses against the recessed portion when the valve is actuated. It is characterized by comprising a control means for selectively issuing a locking and locking release output to the operating means so as to cause the valve to enter and disengage when the valve is stopped.

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 in one cylinder of a multi-cylinder gasoline engine (not shown) that performs normal operation and deactivation operation in a timely manner (here, only one cylinder is shown, but it can be installed in the same way on multiple cylinders).
mounted against. 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). Further, inside the cam cap 9, an oil passage 11 that communicates with an in-shaft oil passage 201, which will be described later, is formed vertically and connected to a hydraulic operating device OC as an operating means, which is connected to a controller 14 as a control means. connected to. That is, the lower end of the oil passage 11 opens into the annular groove 101 of the bearing portion 10, and the upper end is connected to the oil control valve 13 via the oil pipe 12. The oil control valve 13 is a three-way solenoid valve that is operated by an output signal from a controller 14 made up of a microcomputer. During normal valve operation, the oil from the oil pump 15 is stored in an accumulator 151 serving as an oil reservoir, and the oil is allowed to flow into the oil control valve 13. port 13
1, and when the valve is stopped, the oil is transferred to operation port 13.
2 to the oil pipe 12 side. Note that the reference numeral 133 indicates a drain port.
On the other hand, the bearing part 10 has a connecting passage 10 that communicates with an in-shaft oil passage 201 in the camshaft 2 from a part of the annular groove 101.
2 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 is always connected to the annular groove 101 or the oil passage 1.
1 to the oil pipe 12 side.

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. A conical locking hole 163 as a concave portion is formed in this annular inner wall surface. In addition, cam 16
In order to prevent the camshaft from shifting in the direction of the center line l, the stopper pin 17 has a notched circular shape and has both sides 162 flattened and is irremovably attached to the camshaft 2.
It is possible to slide into contact with the The cam shaft 2 has a sliding wall surface 20 that is located between the pair of stopper pins 17 and that is slidable on the annular inner wall surface 161 that forms the sliding surface of the cam.
2 is secured. A guide hole 18 as a guide portion is formed in the camshaft 2 surrounded by the sliding wall surface 202 and has a center line l1 perpendicular to the center line l. The guide hole 18 has an in-shaft oil passage 201 at its center.
One end is open to the sliding wall surface 202, and the other end faces a bottom wall 205 having a narrow passage 204. In addition, narrow path 2
04 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.
The total length of the guide hole 18 is slightly shorter than the length of the guide hole 18, and a hydraulic pressure receiving surface 191 as an operating surface is formed in the horizontal hole at the center thereof. Note that the hydraulic pressure receiving surface 191 is also formed on the tip surface of the protruding portion 194. Moreover,
Below the partition wall 192 forming the hydraulic pressure receiving surface 191,
That is, the bottom wall 205 side is formed as a piston portion 193, and this piston portion 193 is urged by the spring 21 in a direction away from the bottom wall 205. The protruding portion 19 is located above the piston portion 193, that is, on the opening side.
4, and its tip 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 always urged to project its protruding portion 194 from the guide hole 18 and plunge into the locking hole 163 by the elastic force of the spring 21, and when receiving hydraulic pressure, the protruding portion 194 This is a configuration in which the guide hole 18 is moved into the guide hole 18.

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 rotational speed, engine load, transmission gear position, clutch on/off, etc. as the driving condition of the vehicle. An output signal is output to the oil control valve 13 only when this is the case, 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 inlet 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 operation port 132 (indicated by a dashed line in FIG. 1), and this pressure oil 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. For this reason,
The exhaust valve 7 is kept fully closed. Similarly, since the air supply valve (not shown) is also maintained in a fully closed state, the cylinder equipped with both of these valves enters a cylinder deactivation operation in which output generation is stopped. Note that if the controller 14 stops the output again, the plunger 19 will again release the spring 2.
When the projecting part 194 faces the locking hole 163 of the cam, it plunges into it, the cam 16 and the camshaft 2 rotate together, and the cylinder returns to the normal state capable of generating output. Start driving.

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-stop operation, and fuel consumption can be kept low. In particular, this valve stop device 1 does not increase the mass of the swinging end like the rocker arm 6, and the plunger 1 is installed inside the rotating camshaft 2.
9 is added, the mass of the valve train is smaller than that of the conventional device, and there is an advantage that high-speed operation can be easily performed. Moreover, the structure is relatively simple, the cost is low, and the reliability is improved. Furthermore, even if the spring 21 becomes sagging, if the plunger 19 is set so that its center of gravity G is located on the opening side of the center line l of the camshaft, the cam 16 and the camshaft will be maintained even by the centrifugal force. This has the advantage of ensuring the engagement of the two. Furthermore, there is an advantage that sufficient commonality of parts can be ensured with engines that are not equipped with the valve stop device 1.

The cam 16 shown in FIG.
1 was formed with a tapered locking hole 163, but instead of this, as shown in FIG.
3a may also be formed. In this case, the stopper pin 17 not only locks the cam 16 but also the oil stopper plate 23 that abuts the side surface 162 of the cam 16.

The valve stop device 1 shown in FIG. 1 includes a plunger 19 as a locking member, and a hydraulic pressure receiving surface 191 thereof has a
The valve stop device 1a is constructed as shown in FIG. Good too. That is, the cam 16b is externally fitted onto the sliding wall surface 201 on the camshaft 2a, and is held by a stopper pin 17 so as not to be displaced, and a tapered locking side hole 24 is provided as a concave portion on one side of the cam.
An annular slider 26 is fitted onto the key 25 on the camshaft 2a as a guide part, and the slider 26 has an annular tapered surface 26 as a protruding part.
1 and an annular groove surface 262 as an operation surface, a lever 27 that applies a pressing force in the direction of the center line l is inserted into the annular groove surface 262, and a solenoid 28 is connected to one end of the lever 27. good. In this case, first, when there is no output signal from the controller 29 being given to the solenoid 28, the return spring 30
61 is pressed into the locking side hole 24, and the slider 2
6 integrates the cam 16a and the camshaft 2a,
Normal operation is performed in which the valves are opened and closed. on the other hand,
When an output signal is applied to the solenoid 28, the lever 27 is actuated and the slider 26 is moved along the key 25.
slides, the tapered surface 261 and the locking side hole 24 are disengaged, the camshaft 2a rotates idly relative to the cam 16a, and a cylinder deactivation operation is performed.

The valve stop device 1a shown in FIG. 5 has the same effect as the valve stop device 1 shown in FIG. In particular, since the solenoid 28 is used as the operating means, an oil passage is not required, and the structure is advantageously simplified.

In the above, the valve stop devices 1 and 1a have been explained as being used in an engine that enables cylinder deactivation operation, but they can also be installed in the valve train of a 4-valve engine to prevent swirl at low output. It is also possible to operate two supply and two exhaust valves at a time of high output by using only the reinforcement air supply port.

[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 shows a front and side sectional view of a cam used in place of the cam in FIG. 1, and FIG. 5 shows a sectional view of a main part of a valve stop device as another embodiment of the present invention. . 1, 1a... Valve stop device, 2, 2a... Cam shaft, 16, 16a... Cam, 18... Guide hole,
19...Plunger, 194...Protrusion, 191
... Hydraulic pressure receiving surface, 24 ... Locking side hole, 25 ... Key, 26 ... Slider, 261 ... Tapered surface, 2
62... Annular groove surface, 14... Controller, 21
... Spring, 161 ... Annular inner wall surface, 163 ... Locking hole, OC ... Hydraulic operating device.

Claims (1)

[Claims] 1. A camshaft in the valve train of an internal combustion engine, a cam that is slidably fitted onto the camshaft, a recess formed on the sliding surface of the cam, and the above-mentioned cam that faces the recess. A guide portion formed on the camshaft, a locking member slidably fitted into the guide portion, a protrusion formed on the locking member to be locked in the recessed portion, and A biasing means for urging the protrusion in the direction of locking the protrusion in the concave part, and a pressing force for pressing the protrusion in the unlocking direction against the concave part are formed on the locking member. an operating surface that has been opened, an operating means that applies a pressing force to the operating surface in the direction of releasing the lock, and a protruding portion of the locking member that enters the recessed portion when the valve is actuated and is released when the valve is stopped. A valve stop device comprising: a control means for selectively issuing a locking and locking output to the operating means to cause the valve to stop.