JPH0336131B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a valve train for an engine, and more specifically, the present invention relates to a valve train for an engine, and more specifically, the present invention relates to a valve train for an engine.
The present invention relates to surging prevention measures for a valve train equipped with a valve deactivation mechanism that holds an exhaust valve in a closed position, that is, in an inoperative state and stops operation of its cylinder.

(Prior Art) Conventionally, as a valve train for an engine, for example, as disclosed in British Patent No. 1275328 and drawings, a rocker arm of a specific cylinder is connected to a cam-side arm that receives force from a camshaft, and
It is divided into a valve-side arm that drives the intake and exhaust valves, and both arms are supported so as to be movable relative to each other around the rocker shaft, and also supported movably on the cam-side arm so as to come into contact with the valve-side arm using a hydraulic device. A pressed plunger is provided to restrict the relative movement of both arms toward each other and transmit the force from the camshaft to the valve side arm, which drives the intake and exhaust valves to open and close. It is something. By the way, in such a configuration, when the engine is in a low load range where not much engine output is required, by relieving the hydraulic pressure of the hydraulic system and eliminating hydraulic action on the plunger, both arms are moved relative to each other and the camshaft is In order to prevent the force from being transmitted to the valve side arm,
Reduced cylinder operation is performed in which the exhaust valve is held in a closed or inactive state and the operation of a specific cylinder is stopped. This reduces displacement in the low load range and reduces pumping loss, reducing fuel consumption. It is possible to do so. In this case, during cylinder reduction operation, the only movable part of the valve train is the cam side arm, and the inertial mass is reduced accordingly, so surging is less likely to occur even when the engine rotates at high speeds, and the valve side arm Also, since the intake and exhaust valves do not jump, it is advantageous in ensuring that the operation of a specific cylinder is stopped.

However, in the above-mentioned conventional device, since the cam-side arm is provided with a valve deactivation mechanism consisting of a plunger and a hydraulic device for pressing the plunger, the inertial mass of the movable part increases accordingly, resulting in a reduction in There is a problem in that there is a lack of reliability in preventing the occurrence of surging in the high rotation range during cylinder operation.

(Object of the Invention) The object of the present invention is to install a valve deactivation mechanism that controls the relative movement of the cam side arm and the valve side arm supported on the rocker shaft to the valve side arm, which is a non-movable part during cylinder reduction operation, as described above. By providing this, the inertial mass of the movable parts during reduced-cylinder operation is reduced as much as possible, and the occurrence of surging during reduced-cylinder operation is more reliably prevented.

(Structure of the Invention) In order to achieve the above object, the solution means of the present invention is to combine a rocker arm that presses and opens intake and exhaust valves of an engine with a cam-side arm that receives force from a camshaft, and a cam-side arm that receives force from a camshaft. The valve is divided into a valve-side arm that drives the valve, and both arms are supported so as to be movable relative to each other around a rocker shaft. The plunger is brought into contact with the cam side arm to restrict the relative movement of both arms, and its movement is prevented, while during cylinder reduction operation the plunger is prevented from moving so as to allow relative movement of both arms. A valve deactivation mechanism consisting of a plunger control device that allows the valve to be operated is provided.

This allows the plunger to come into contact with the cam-side arm during all-cylinder operation (normally), restricting the relative movement of both arms, and transmitting the force from the camshaft to the valve-side arm. While the arm opens and closes the intake and exhaust valves, during cylinder reduction operation the plunger is moved to enable relative movement between both arms, and by not transmitting the force from the camshaft to the valve side arm, The valve side arm and the valve deactivation mechanism are not moved, and
The intake and exhaust valves are kept in a closed state, that is, in an inoperative state.

(Effects of the Invention) Therefore, according to the present invention, by providing the valve-side arm with the valve deactivation mechanism, the inertia weight of the cam-side arm, which is a movable part during cylinder reduction operation, is reduced as much as possible. This makes it possible to reliably prevent the occurrence of surging in the high speed range of the engine during cylinder reduction operation, eliminating the occurrence of jumps in the valve side arms and intake and exhaust valves, and thus reducing engine speed throughout the entire speed range. This makes it possible to improve the reliability of reduced-cylinder operation.

(Example) Hereinafter, an example as a specific example of the technical means of the present invention will be described based on the drawings.

FIG. 1 shows an embodiment in which the present invention is applied to an in-line four-cylinder engine. H is a cylinder head disposed on a cylinder block (not shown). In the cylinder block, first to fourth cylinders C are formed at equal pitches in order from the front side (left side in FIG. 1). A camshaft 1 extending in the front-rear direction is disposed in the left-right center of the cylinder head H and is supported by rocker brackets R..., and the portions of the camshaft 1 corresponding to the cylinders C are provided with suction. , exhaust cam portions 2 and 3 are formed. Rocker shafts 4, 4 extending parallel to the camshaft 1 are disposed on both left and right sides of the camshaft 1 and are supported by the rocker brackets R.

On the other hand, although not shown, the cylinder head H is formed with an intake port and an exhaust port corresponding to each cylinder C, and is also provided with an intake valve 5 and an exhaust valve 6 for opening and closing the intake and exhaust ports. It is being The intake and exhaust valves 5 and 6
is biased in the valve closing direction by a valve spring, and the upper ends of its stem portions protrude to the outside of the rocker shafts 4, 4 on both the left and right sides.

The rocker shafts 4, 4 on both the left and right sides are as follows:
Intake rocker arms 7 and 8 and exhaust rocker arms 9 and 10, which press and open the intake and exhaust valves 5 and 6, are rotatably supported.
Each rocker arm 7 to 10 is provided such that its inner end abuts the corresponding cam portion 2, 3 of the camshaft 1, and its outer end abuts the upper end of the stem portion of the intake and exhaust valves 5, 6. As the camshaft 1 rotates, the cam portions 2 and 3 press the intake and exhaust valves 5 and 6 against the biasing force of the valve spring to open the valves at a predetermined timing. ing.

Of the rocker arms 7 to 10, the rocker arms 7 and 9 for intake and exhaust of the first cylinder C and the fourth cylinder C are provided with a valve deactivation mechanism, which is a main component of the valve train according to the present invention. . This valve deactivation mechanism will be explained with reference to the exhaust rocker arm 9 of the first cylinder C.As shown in detail in FIGS. 11 and a valve-side arm 12 that presses the exhaust valve 6.
1 and 12 are supported for relative movement around the rocker shaft 4. A guide hole 13 that opens toward the cam side arm 11 is formed in the upper part of the valve side arm 11.
A cylindrical plunger 14 is movably supported on the cam side arm 11 by a spring 15 installed in the guide hole 13.
is biased so as to come into contact with.

Further, a lock-off plate 16 having a surface perpendicular to the guide hole 13 is supported on the upper part of the valve-side arm 11 so as to be movable in the axial direction of the rocker shaft 4. Above cam side arm 1
As shown in FIG. 4, a guide sleeve 17 movable in the axial direction is biased toward the rocker bracket R side by a return spring 18 on the rocker shaft 4 between the rocker bracket R and the rocker shaft 4. A ring-shaped drive sleeve 19 is supported between the guide sleeve 17 and the rocker bracket R, and the end of the lock-off plate 16 is attached to the upper surface of the guide sleeve 17. There is.

On the other hand, as shown in FIG. 1, a solenoid 20 is disposed at the rear of the cylinder head H, and an excitation shaft 21 that is pressed forward when the solenoid 20 is activated is connected to the solenoid 20. The excitation shaft 21 is a rocker bracket R.
The drive sleeve 1 is supported by the drive sleeve 1 and extends forward.
9, and the return spring 1
When the solenoid 20 is actuated, the lock-off plate 16, which is in the locked position, is moved forward through the drive sleeve 19 and the guide sleeve 17 to the unlocked position by the biasing force of the lock-off plate 16.

The middle part of the plunger 14 is notched to reduce the shaft diameter to form an engaging part 22, while the lock-off plate 16 is formed with a switching hole 23 as shown in FIG. There is. The switching hole 23 consists of a locking hole portion 23a that is slightly larger than the shaft diameter of the plunger engaging portion 22, and an insertion hole portion 23b that is connected to the rear of the locking hole portion 23a and is slightly larger than the shaft diameter of the plunger 14. , when the lock-off plate 16 is positioned at the lock position due to the deactivation of the solenoid 20, as shown by the solid line in FIG. 14, and presses the cam-side arm 11 with the plunger 14 protruding from the guide hole 13, thereby restricting the relative movement of the cam-side arm 11 and the valve-side arm 12 toward each other. The arm 11 transmits the force received from the camshaft 1 to the valve-side arm 12 via the plunger 14 to open and close the exhaust valve 6, while locking off the exhaust valve 6 by operating the solenoid 20 as shown by the imaginary line in FIG. plate 16
is positioned at the release position, the insertion hole 2
3b is located coaxially with the plunger 14 to allow movement of the plunger 14 and relative movement between the cam side arm 11 and the valve side arm 12, thereby reducing the force received by the cam side arm 11 from the camshaft 1. The plunger control device A is configured to absorb the exhaust gas through the plunger 14 by compression deformation of the spring 15 and not transmit it to the valve-side arm 12, thereby holding the exhaust valve 6 in a closed position, that is, in an inoperative state. Incidentally, the intake rocker arm 7 is also configured with a valve deactivation mechanism similar to that of the exhaust rocker arm 9.

Therefore, in the medium load range or high load range of the engine, the first and fourth solenoids are not operated without operating the solenoid 20.
While cylinders C and C are operated to perform full-cylinder operation, in the low load range of the engine, the solenoid 20 is activated to stop the operation of the first and fourth cylinders C and C to perform reduced-cylinder operation. being done.

In addition, 24... is a spring that restrains the movement of the rocker arms 7 to 10 in the direction of the four axes of the rocker shaft, 25 is a sprocket that drives the camshaft, and 26 is a spring.
is an adjustment screw for adjusting the valve brush,
30 is the plunger 1 in the valve side arm 12.
4 is the abutting part that abuts, and is made of a chip material with excellent wear resistance. 27 is a lock nut for adjusting the position of the excitation shaft 21, 28 is a boss for attaching a distributor, and 29 is a cylinder head cover.

Therefore, in the above embodiment, the operation or stopping of the first and fourth cylinders C and C can be freely switched, so that all-cylinder operation is sufficient in the medium load range or high load range of the engine. While generating the required engine output, in the low load range of the engine, cylinder reduction operation is performed to generate the required output while halving displacement to reduce fuel consumption and halving pumping loss to reduce horsepower loss. , thus the fuel consumption rate can be reduced.

In addition, during cylinder reduction operation, the only movable part of the valve train is the cam-side arm 11, but since the cam-side arm 11 is not provided with the plunger 14 or the lock-off plate 16, the inertia of the movable part Since the mass can be reduced as much as possible, surging does not occur even when the engine rotates at high speeds, and the valve side arm 12 and the intake and exhaust valves 5 and 6 do not jump. Therefore, the operation of the first and fourth cylinders C and C can be reliably stopped, cylinder reduction operation can be performed reliably over the entire engine speed range, and the fuel consumption rate can be further reduced. I can do it.

Furthermore, since the lock-off plate 16 is supported movably in the axial direction of the rocker shaft 4 at the upper part of the valve-side arm 11, the upper part of the valve-side arm 11 can be formed as compact as possible, for example, as a lock-off plate. Compared to the case where the off-plate is movably supported in the direction orthogonal to the rocker shaft 4, the increase in inertial mass of the moving parts can be greatly suppressed, which reduces engine surging in the high-speed range even during all-cylinder operation. This is advantageous in preventing.

In the above embodiment, a mechanism including the lock-off plate 16 and the like is used as the plunger control device A that allows or prevents movement of the plunger 14, but a hydraulic device that hydraulically moves the plunger may also be used.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is a plan view of the cylinder head, FIG. 2 is an enlarged view of the main part of FIG. 1, FIG. 3 is a cross-sectional view taken along the line - FIG. 2 is a sectional view taken along the - line in FIG. 2; 1...Camshaft, 5...Intake valve, 6...Exhaust valve, 7, 8...Rotzker arm, 9, 10...
...Lotsuker arm, 11...Cam side arm, 12
... Valve side arm, 14 ... Plunger, 15
... Spring, 16 ... Lock-off plate,
17... Guide sleeve, 18... Return spring, 19... Drive sleeve, 20... Solenoid, 21... Excitation shaft, 22... Engaging portion,
23...Switching hole, A...Plunger control device.

Claims (1)

[Claims] 1 The rocker arm that presses and opens the intake and exhaust valves of the engine is divided into a cam-side arm that receives force from the camshaft and a valve-side arm that drives the intake and exhaust valves, and both arms are connected to the rocker shaft. A plunger is supported on the valve side arm so as to be movable relative to the valve side arm, and the plunger is supported on the valve side arm so as to be movable relative to the valve side arm. A valve deactivation mechanism is provided, which includes a plunger control device that prevents the plunger from moving while in contact with the arm, and allows the plunger to move so as to allow relative movement of both arms during cylinder reduction operation. An engine valve train characterized by: