JPH0373728B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a four-stroke engine. More specifically, it is equipped with a valve opening/closing timing and opening adjustment device, which automatically adjusts the intake and exhaust valves, opening/closing timing, and opening according to the rotation speed per unit time (for example, rpm, hereinafter referred to as rotation speed). This relates to a four-stroke engine that can be changed to

[Conventional technology]

In a 4-stroke engine, due to the flow inertia of the mixed gas and exhaust gas, timing adjustments are required such as opening the intake and exhaust valves before vertical dead center and closing them later. It is well known that in order to improve combustion efficiency, the lead and lag angles must be adjusted to appropriate values commensurate with the rotational speed. However, under normal operating conditions, the engine does not operate at a constant speed as in a laboratory, but in reality, the speed is constantly changing. Therefore, even if the timing of opening and closing the valve is set to match a certain rotation speed during normal operation, the rotation speed at which good results can be obtained is limited to a certain range. This leaves problems in the vehicle engine, such as insufficient acceleration due to insufficient torque, failure to reduce the number of gears, and complicated transmission gears. In addition, the opening degree of the valve needs to increase combustion efficiency and reduce harmful exhaust gases at extremely low speeds or idling, and at high speeds it is necessary to increase the opening degree to ensure sufficient intake and exhaust. It is also known that there are However, at present, the opening degree is constant regardless of the speed, and it is generally impossible to change it.

An example of a proposal to make the valve opening/closing timing variably adjustable according to the engine speed is described in "Monthly Automobile" (Hong Kong, January 1983) by Stephen Michell. Mitsuiru makes the camshaft hollow, inserts a transmission shaft rotated by a timing chain into the center hole, and connects both shafts to each other by a distance corresponding to the rotational speed through a specially designed joint. We are proposing something that is connected so that it is offset from the other side. As shown in Figures 6a and 6b, where the camshaft _S2 and the transmission shaft _S1 are eccentric to each other in the horizontal direction, the 0
Within the rotation range of ~180°, a delay angle α can be obtained between both axes S ₁ and S ₂ as shown in Figure 6a, and within the lower rotation range of 180~360°, as shown in Figure 6b. As shown, an advancing angle β can be obtained between both axes S ₁ and S ₂ . As a result, when the engine rotates at low speed, the opening timing of the intake valve is delayed to reduce the overlapping time with the exhaust valve, and the expansion cycle is extended by delaying the opening timing of the exhaust valve. It is something that occurs.

On the other hand, a proposal for making the valve opening variable variable is described in "Monthly Automobile" (Hong Kong, August 1983) by Andrea Titolo. It has a camshaft with a conical taper cam that can move in the axial direction, a semicircular grooved catch provided at the tip of the tappet, and a semicircular cross section. The camshaft is composed of a piece-like cam follower that can swing along the engine speed, and the camshaft is configured to move according to the engine speed by combining a hydraulic device that generates a hydraulic output according to the engine speed and a balance spring. Thus, the stroke of the tappet is changed by changing the position of the tapered cam in contact with the cam follower. According to Teitro, the intake valve opens at a forward angle of approximately 10 degrees and closes at a delay angle of approximately 10 degrees.
At 10°, the results show that if the duration of the open state of the exhaust valve is extended by 6°, the change in valve opening can be increased by about 30% compared to the conventional one.

[Problem that the invention seeks to solve]

However, although the above-mentioned prior art can improve the combustion efficiency and output of the engine to some extent, the effect is limited to the effect of individual means, and the synergistic effect of automatic adjustment of valve opening degree and automatic adjustment of opening/closing timing (for example, , the number of transmission gears can be reduced by expanding the rotation range in which maximum torque can be obtained), and the clearance of each contact transmission point in the conventional valve mechanism cannot be eliminated, resulting in impact vibration. This is far from a noiseless engine, and since the adjustment operation is via a camshaft that transmits rotational torque, the mechanical or electrical engine speed detection signal must be amplified by a servo mechanism, etc. There are problems such as not being able to generate enough output to move the camshaft.

In view of the above problems, the present invention first aims to provide a four-stroke engine with a valve opening system that can automatically change the opening/closing timing and degree of opening of intake and exhaust valves, etc., in accordance with the engine speed. The present invention provides a degree and opening/closing timing adjustment device.

The present invention also provides a valve opening degree and opening/closing timing adjustment device that does not need to amplify the detection signal from the rotation speed detector to a drive output sufficient to move the camshaft as in the conventional case, and has a small output. This provides a 4-stroke engine that requires only a drive unit of 1.

The present invention also provides a four-stroke engine in which the rocker arm swings under the action of cam rotation to actuate a tappet at one end of the rocker arm to open a poppet valve. The purpose of the present invention is to provide a four-cycle engine in which there is almost no clearance in the engine, and vibration noise caused by the clearance is minimized during engine operation.

The present invention further provides a four-stroke engine equipped with a regulating device in which the operation of the regulating device is damped at the end of each cycle to cushion shocks caused by sudden stops.

[Means for solving problems]

The four-stroke engine of the present invention is swingable with one end as a fulcrum, and the other end is in contact with a tappet that is biased by a valve spring to keep the poppet valve closed at all times, and rotates. A rocker arm is provided with a rocker arm whose other end pushes the tappet against the biasing force of a valve spring to open the poppet valve by periodically rocking under the action of a cam. In a cycle piston engine, the tip of a plunger body is inserted into one end of the rocker arm, which serves as a fulcrum, so as to slide relative to the cylinder and to freely change and adjust the stroke, and abuts the fulcrum. At the same time, the insertion end of the plunger body is urged to extend toward the tip by a pressure spring that comes into contact with the bottom of the cylinder, and a detector detects the engine rotation speed.
The valve opening degree at which the sliding stroke of the plunger body is changed by means of increasing/decreasing the relative stroke between the plunger body and the cylinder via a transmission mechanism by means of a drive device that outputs output in response to the detection signal. It is also characterized by being equipped with an opening/closing timing adjustment device.

In the present invention, the stroke adjusting means of the valve opening degree and opening/closing timing adjusting device is configured as follows. That is, the cylinder is provided with an oil inlet that communicates with a drench bar containing hydraulic oil, and a ring gear is formed on the outer peripheral surface of the cylinder to mesh with the rack and rotate the cylinder relative to the plunger body. Configure. The plunger is formed in the shape of a hollow rod, and its tip fits into the end of the rocker arm, and has an oil inlet hole so that the inside of the plunger always communicates with the oil inlet of the cylinder, and a lower part of the cylinder and its oil outlet, respectively. Provide oil vent holes and communication openings. A check valve is used to allow the hydraulic oil to move in one direction between the oil inlet hole and the oil outlet hole in the plunger body, and the oil outlet of the cylinder is connected to the oil outlet hole in the plunger body. It is formed so that the communication range can be changed by rotating the axis.

In the present invention, the oil outlet of the cylinder is formed into a substantially inverted right triangle tapered in the circumferential direction.

In the present invention, the oil outlet of the plunger main body is formed into a drop shape that tapers substantially diagonally upward.

In the present invention, it is also preferable that the plunger body has a recessed portion near the oil inlet so that the oil inlet always maintains communication with the oil inlet even while the oil inlet is moving relative to the cylinder.

In the present invention, it is also preferable that the biasing spring of the plunger body has a strength that can substantially return the plunger when it is not acting on the rocker arm, or a strength that is lower than that of the valve spring.

In the present invention, it is further preferable that the transmission mechanism is a linked rod rotation mechanism.

[Effect]

According to the configuration of the present invention described above, the poppet valve is moved from the closed state to the open state by pushing the poppet biased by the valve spring with the rocker arm that swings due to the action of the rotating cam. In an engine, one end that serves as a fixed fulcrum when the rocker arm swings is connected to the plunger body of an opening/closing degree and opening/closing timing adjusting device, which is comprised of a plunger body fitted into a cylinder so that its stroke can be changed freely. Since they are in contact with each other, the fulcrum position is not fixed but changes due to the difference in the elastic force of the pressing spring with respect to the leaf spring. Therefore, even if the rocker arm that pushes the tappet is acted upon with a constant amplitude of the cam, it will not operate immediately, but will operate to push the tappet with a delay until the plunger stops changing. Furthermore, since the distance from the fulcrum of the Rocker arm to the cam action point and tappet action point, and the stroke taken by the tappet to fully open the hoppet valve, are each constant,
A delay to the tappet will simultaneously reduce the valve opening. On the other hand, as a means for changing the fulcrum position, the output operation of a drive device that receives a detector from an engine rotational speed detection device and generates an output corresponding to the signal gives a stroke commensurate with the rotational speed and acts as a fulcrum. The hydraulic plunger is adjusted so that the plunger body stops when it reaches the position where it should move, so the plunger body stops after moving a distance proportional to the engine rotational speed, and acts as a fulcrum for the rocker arm. The action of the cam pushes the tappet to a predetermined opening degree and at a predetermined timing, allowing the hoppet valve to open to an appropriate opening degree.

With respect to the operation described above, one embodiment of the present invention provides a method for controlling the movement of hydraulic fluid as a means of increasing or decreasing the relative stroke of a hydraulic plunger. That is, by providing an oil inlet/outlet hole and an oil inlet/outlet in the cylinder and the hollow plunger body, respectively, they communicate with the drench yam bar.
In addition, a check valve is provided in the plunger body to restrict the movement of hydraulic oil in one direction from the oil inlet to the oil outlet hole. At the same time, when the oil outlet of the cylinder that communicates the oil outlet and the drench yambar moves along the axial direction of the plunger body, the position where communication is interrupted changes as a result of rotating itself along the circumferential direction. It's becoming like that. As a result, the plunger body is pushed and moves toward the inside of the cylinder while discharging the hydraulic oil into the drench yam bar. During this time, the hydraulic oil moves from the drench yam bar into the plunger through the oil inlet and oil inlet hole. The stroke can be adjusted until the communication reaches a position where the communication is cut off and is stopped by the confining pressure of the hydraulic oil sealed in the lower part of the cylinder. The drive device generates an output responsive to the signal from the engine speed detector, which drives the cylinder through a rack and pinion mechanism to rotate through a corresponding angle.
In other words, the detector detects a signal at that speed every moment, and the drive device outputs the signal to rotate the cylinder at a corresponding appropriate angle, so that the cylinder always follows the speed while the engine is running. At the position where the cylinder rotates, when the cam that rotates at a constant frequency and amplitude acts on the rocker arm, the rocker arm first pushes the plunger body at the fulcrum at one end, and the plunger body slides against the pressing spring, as described above. It can be stopped when the current appropriate stroke is reached, so that only after this time the working end of the rocker arm acts on the tappet and moves the poppet valve with an oscillation amplitude equal to the oscillation amplitude determined by the fulcrum position. You can now open it to the maximum opening. Then, when the cam rotation reaches the second half of the valve-closing cycle, the action on the rocker arm is eliminated, and the tappet is first pushed back by the valve spring to close the poppet valve, and after a delay, the fulcrum at one end of the rocker arm presses against the plunger body. The action is canceled, and as a result, the plunger body moves in the extension direction under the restoring action of the pressing spring. At this time, the lower part of the cylinder expands under reduced pressure, so hydraulic oil can be replenished inside the plunger body through the check valve, and the hydraulic oil can be replenished from the drench yam bar through the oil inlet and oil inlet hole. After the oil flows in and the oil outlet and oil outlet communicate with each other again, the oil is directly replenished and inflowed from the drench yambar until the oil reaches its original state.

As mentioned above, instead of operating and rotating the cylinder via the rack and pinion mechanism by the output of the drive device, a lever is provided protruding from the cylinder,
The cylinder can also be rotated by means of rotating a lever by driving a bar connected to the lever using a drive device.

In addition, the means for adjusting the movement of the hydraulic plunger by controlling the movement of hydraulic oil is such that the bottom of the cylinder is screwed together with a pressure spring so as to be movable in the axial direction, and the drive device is a rack pinion. A similar effect can be obtained by rotating the bottom of the cylinder via a mechanism to move the bottom and use it as an abutment stopper at the lower limit of the stroke of the plunger body.

In addition, in an adjustment device using braking control of a hydraulic plunger, if the oil outlet of the cylinder is formed into an almost inverted right triangle, when the cylinder rotates, the opening edge becomes a tapered hypotenuse, so the position of rotation will change. Therefore, the distance that the plunger body can move before communication is cut off, that is, the stroke, can be changed.

Therefore, if the inverted right triangle of the oil outlet is formed so that it is wide on the low speed side of the engine rotation and tapered on the high speed side, the valve opening degree and opening/closing timing can be controlled over the entire range from low speed at startup to high speed operation. can be adjusted appropriately.

Further, the rotary cam has one end in contact with the plunger body biased by a pressing spring, the other end in contact with a tappet biased by a valve spring, and on the opposite side, the periphery of the cam is oriented in the opposite direction. Because they are in constant contact, the tip of the hydraulic plunger body is in a position where it is constantly pressing against the rocker arm due to the pressure spring, so all clearances can be almost eliminated, which is effective in noise control. be.

In addition, by forming the oil outlet hole in the plunger body into a drop shape that tapers diagonally upward, the communication area is gradually narrowed just before communication is completely cut off by the oil outlet side of the cylinder. Therefore, the shock when stopping is alleviated.

〔Example〕

The present invention will be explained based on one embodiment. The drawings schematically show embodiments of this embodiment for the purpose of explanation.

In the main part side sectional view of FIG. 1, 100 is a cylinder block of a four-stroke engine, and only a portion of its upper end is shown for convenience. In the diagram, spark plug 1
01 is a poppet valve for intake (or intake valve)
It is attached to the opening of the suction passage 103 which is opened and closed by the valve 20.

The upper part of the cylinder block 100 is covered with a shell-shaped cover 102 so as to form a space.

An exhaust passage, not shown in the drawings, is formed on the opposite side of the intake passage 103 and is similarly opened and closed by a poppet valve (exhaust valve), but it is noted that the timing of its operation is different from that of the intake valve 20. Otherwise, the operating mechanism of the present invention is exactly the same, and therefore, in the following description, only the intake valve 20 will be described unless otherwise emphasized.

The valve opening degree and opening/closing timing adjusting device of this embodiment is as follows:
A fitting seat F consisting of a concave hole formed in the upper cover 102 of the cylinder block 100 serving as the main body.
A hydraulic plunger 10 fitted into the valve spring 2, a tappet 21 for opening and closing the poppet valve 20, and a valve spring 2 for always urging the poppet valve 20 to close.
2 and both end portions 31 and 32 thereof are brought into contact with the upper end portion of the tappet 21 and the upper end portion of the plunger 10, respectively, and at the same time, the upper portion slightly closer to the center is brought into contact with the cam 4, and the contact end portion with the plunger body 12 is brought into contact with the cam 4. The tappet 2 is rotated by the rotation of the cam 4 about the fulcrum 32.
It is composed of a rocker arm 3 that moves the other end 31 of the first side up and down.

The hydraulic plunger 10 is constructed by slidingly fitting a substantially hollow cylindrical plunger body 12 into a cylindrical cylinder 11 so as to be vertically movable. An orifice 134 is formed at the lower end of the plunger body 12 and has an opening that is narrowed to a small size. A check valve 13 consisting of a steel ball 133 in contact with an orifice 134 limits the flow of hydraulic oil to only one direction, from inside to outside.
The lower end of the plunger main body 12 is further urged by a pressing spring 14 fitted to the bottom of the cylinder 11 so that the upper end of the plunger main body 12 always projects upward, and the upper end is formed with a step. Excessive protrusion is prevented by the shoulder portion coming into contact with the pressing washer 16 that is locked by the snap spring 17 that is engaged with the opening of the cylinder 11. Note that the pressure spring 14 is smaller than the elastic biasing force of the valve spring 21 that closes the hoppet valve 20.

The plunger body 12 further includes a cylinder 1
A part of the outer circumferential surface that comes into sliding contact with the ring 1 is formed into a wide ring-shaped recessed neck part E. An oil inlet hole C is provided that communicates between the neck portion E and the inside, and is also communicated with a drench yam bar 15 formed in the cylinder book 100 through an oil inlet A bored in the cylinder wall. The inlet hole C is also an oil outlet hole D on the lower end side circumferential wall separated from the check valve 13, and an oil outlet communicating with the drench yam bar 15 is also on the circumferential wall of the cylinder 11 at a position corresponding to the upper limit position of the hole D. By drilling the hole B and filling it with hydraulic oil, the drench yam bar 15, the cylinder 11, and the plunger body 1 are assembled.
2. The inside means that the function of the check valve 13 allows the oil inlet A, the neck E, the oil inlet C, the inside of the plunger body 12, and the orifice 13 to be opened from the drench yam bar 15.
4. Form a closed path for the hydraulic oil to return to the chamber 15 via the lower part of the cylinder 11, the oil outlet D, and the oil outlet B. However, by appropriately selecting the width of the neck portion E, the oil inlet A and oil inlet C can maintain communication throughout the entire process of vertical movement of the plunger body 12. In the present embodiment, as shown in FIG. As shown in the plan view of FIG. 3, the outer peripheral edge of the opening of the cylinder 11 is formed as a link gear 19. The link gear 19 meshes with a rack 18 that is slidable along the upper surface of the cylinder block 100 in a direction perpendicular to the axis of the cylinder 11 (in the direction indicated by arrow P in FIG. 4).

The rack 18 is driven by a drive mechanism that generates an output corresponding to the rotation speed detected by an engine rotation speed (rpm) detector (not shown), so that it slides by an amount commensurate with the rotation speed. It is configured. The plunger body 12 is configured not to rotate about the abutting end 32 of the rocker arm 3 through a fitting connection (not shown) or the like.

Next, how this embodiment operates with the above configuration will be explained.

First, before starting the engine, the plunger body 12 of the hydraulic plunger 10 is pushed by the elasticity of the spring 14, and the plunger arm 3 is pushed upward to a position where it comes into contact with the one end 32 of the rocker arm 3, and the cylinder 11
The inside of the plunger body 12 is filled with hydraulic oil.

When the engine is running and running at low speed, the rotation of the crankshaft is synchronously transmitted to the camshaft via the timing mechanism, causing the cam 4 to push down the rocker arm 3. Here, the forces of the pressing spring 14 and the valve spring 22 acting on both ends of the rocker arm 3 from the opposite side are larger, so the plunger body 12 is pushed first and descends, causing the cylinder 1
The hydraulic oil in the check valve 13 and below in the check valve 1 is moved to the drench yam bar 15 through the oil outlet D and the oil outlet B in order. The discharge is interrupted when the oil outlet D and the oil outlet B move relative to each other and are no longer in communication with each other, and as a result, the plunger body 12 no longer descends due to hydraulic resistance. Only then, with the upper end of the plunger body 12, that is, the end 32 of the rocker arm 3 as a fulcrum, the opposite end 31 pushes down the tappet 21 against the valve spring 22, opening the poppet valve 20.

As the cam 4 continues to rotate and enters the second half of its rotation, the push-down action on the rocker arm 3 is gradually released, and when the valve spring 22 is finally fully extended and the poppet valve 20 is completely closed, the rocker arm 3
Since the acting force on the end 31 of is also eliminated, the other end 32
The pressing spring 14 in the cylinder 11 becomes dominant on the side and causes the plunger body 12 to rise. At that time, although the lower volume inside the cylinder 11 increases, the oil outlet D and the oil outlet B do not communicate immediately, so the hydraulic oil flows from inside the plunger body 12 to the check valve 13 blocking the orifice 134. At the same time, the plunger body 12 is replenished with the flowed-out amount of hydraulic oil from the drench yam bar 15 through the oil inlet A, the neck portion E, and the oil inlet hole C. When the oil outlet D and the oil outlet B communicate with each other due to the rise of the plunger body 12, the chamber 1
The replenishment from 5 is switched to go through the oil outlet B and the oil outlet D in reverse, and when the cam 4 returns to its origin, the plunger body 12 also returns to its starting position.

In the present invention, at the time of design, the position at which the plunger body 12 descends and stops is determined so that the opening/closing timing and opening degree of the poppet valve 20 during low-speed idling operation are the timing and opening degree at which the torque is maximum at that rotation speed. The positions at which the oil outlet D and the oil outlet B are shifted from each other can be set in advance.

When the rotational speed of the engine increases, the drive device drives the rack 18 based on the corresponding signal from the rotational speed detector, and the rack 18 rotates the cylinder 11 via the ring gear 19. cylinder 1
1 rotation causes relative movement in the circumferential direction between the plunger body 12 and the plunger body 12 which does not rotate. As a result, oil outlet D and oil outlet B move relative to each other in the horizontal direction, but oil outlet B has an inverted right triangle shape with a tapered lower limit edge as shown in FIGS. 2 and 4. During the vertical descent process of the plunger body 12, the range in which they can communicate with each other changes in the direction of becoming shorter. That is, in FIG. 4, oil outlet B
When the oil reaches position _B2 by moving horizontally from position _B1 in the direction of arrow P with respect to oil outlet D,
The communication with the oil outlet D is shortened from the descending stroke DD ₁ to the descending stroke DD ₂ , and the position where the plunger body 12 acts as a fulcrum with respect to the end 32 of the rocker arm 3 becomes higher, and at the same time, the operation The timing is earlier and the operating time is longer. On the other hand, since the cam 4 rotates periodically with a fixed eccentricity, the changes in the fulcrum position and timing of the plunger body 12 depend on the amplitude, timing, and timing of the depression of the tappet 21 at the other end 31 of the rocker arm 3. During engine operation, the fulcrum takes a position according to the rotational speed, and changes as the rotational speed changes, and as a result, the opening degree and opening/closing timing of the poppet valve 20 can be changed.

〔Effect of the invention〕

As is clear from the description of the above embodiments, using the displacement output from the rotation speed detector and the drive device,
If the cylinder of the hydraulic plunger of the valve opening degree and opening/closing timing adjusting device according to the present invention is rotated accordingly via the rack and pinion mechanism, the plunger body that is in contact with the end that is the fulcrum of the rocker arm will be synchronized with the engine. The rocker arm, which receives the downward force of the cam that rotates, preferentially presses the fulcrum end due to the greater resistance force of the valve spring of the tappet that abuts the other end, and therefore is pushed down and descends. At this time, the hydraulic oil filled in the closed chamber formed between the plunger body and the bottom of the cylinder passes through the oil outlet at the bottom of the plunger body and the oil outlet at the bottom of the cylinder that communicates with it. By discharging the air, the sealed chamber can be compressed and lowered. Therefore, the oil outlet formed in an inverted triangle moves relative to the oil outlet hole as the cylinder rotates, and while the plunger body is descending, the time for the oil outlet to communicate with the oil outlet and the distance it can descend will vary. , the acceleration will be shortened and the deceleration will be lengthened. Correspondingly, the higher the speed of operation, the sooner the plunger body will stop descending and the distance will be shorter. , the slower the vehicle is driven, the later it will stop and the longer the distance will be. Therefore, in the former case, the tappet is pushed earlier than the other end of the rocker arm, increasing the opening degree of the poppet valve, and the opening time is also long; in the latter case, the pushing down action is delayed and the opening degree is small.
This will shorten the valve opening time. If the above-mentioned action is shown in a diagram, it can be roughly expressed as shown in FIG.

By making the shape of the oil outlet into a drop shape, the area becomes gradually narrowed while the oil outlet is blocked from communication by the lip of the oil outlet.
The plunger body does not stop abruptly in a short period of time, but the discharge of hydraulic oil is attenuated and the plunger body gradually stops, so that the shock caused by the stop can be alleviated. In addition, the hypotenuse edge of the inverted triangle of the oil outlet is not limited to a straight line or a constant slope; it can also be a curved edge in consideration of the contour shape of the cam and corresponding to the engine characteristic curve. You can also change the slope.

As mentioned above, during engine operation, the present invention provides
The opening degree and opening/closing timing of the intake and exhaust valves can be automatically adjusted to the most appropriate value by always corresponding to the rotation speed, and the individual effects of conventional valve opening automatic adjustment devices and opening/closing timing adjustment devices are improved. It is possible to obtain suitable torque in most of the rotation speed range. As a result, starting darts performance in vehicles can be improved, and by reducing the number of gears in the transmission, it is possible to reduce the number of parts, simplify the mechanism, and make it more compact. Furthermore, it is possible to achieve the best combustion at all speeds. Since it can be operated efficiently, it greatly contributes to energy conservation.

In addition, the structure of the present invention is simpler than the known device that separately adjusts the valve opening degree and opening/closing timing, and is compact and low in manufacturing cost. The cylinders are adjusted independently, but it is also possible and easy to coordinately adjust each adjusting device in series or parallel by simple known means.

Further, according to the configuration of the present invention, both ends of the rocker arm are brought into contact with the plunger body and the tappet so as to be elastically biased by the springs. In addition, the entire Rotsuker arm is brought into floating contact with the cam by the elastic bias at both ends, which minimizes the clearance that was a problem in the past, eliminating almost all shock and vibration caused by clearance during movement. In addition to this, when the plunger body acts as a fulcrum, the oil discharged from the oil outlet gradually decreases, thereby alleviating the shock, which significantly reduces vibration noise and eliminates harmless exhaust. This also makes it possible to provide a pollution-free engine.

[Brief explanation of drawings]

FIG. 1 is a schematic side sectional view of the main part of an engine equipped with an embodiment of the valve opening degree and opening/closing timing adjusting device of the present invention, and FIG. 3 is a plan view of the hydraulic plunger shown in FIG. 2 and its vicinity; FIG. 4 is an explanatory diagram showing the operation of the main parts of FIG. 2; and FIG. 5 is a valve showing an overview of the operation of the present invention. The operating curves, FIGS. 6a and 6b, are explanatory diagrams of conventional valve opening/closing timing adjustment mechanisms, respectively.

Claims (1)

[Scope of Claims] 1. It is swingable with one end as a fulcrum, and the other end is in contact with a tappet that is biased by a valve spring to keep the poppet valve in a closed state at all times. A four-stroke engine equipped with a rocker arm whose other end pushes the tappet against the biasing force of a valve spring to open the poppet valve by periodically rocking the rocker arm. One end of the rocker arm, which serves as a fulcrum, is in contact with the tip of a plunger body that is fitted so as to slide relative to the cylinder and to freely change and adjust the stroke. The inserted end is urged to extend in the distal direction by a pressure spring that comes into contact with the bottom of the cylinder, and is driven by a drive device that detects the engine rotation speed with a detector and operates an output in response to a detection signal. , a valve opening degree and opening/closing timing adjusting device is provided which changes the sliding stroke of the plunger body by means of increasing/decreasing the relative stroke between the plunger body and the cylinder via a transmission mechanism; The stroke adjustment means of the timing adjustment device is
The cylinder is provided with an oil inlet and an oil outlet that communicate with a drench bar containing hydraulic oil, and a ring gear is formed on the outer circumferential surface to engage with the rack so that the cylinder rotates relative to the plunger body. is a hollow rod whose tip fits into the end of the rocker arm, and has an oil inlet hole whose inside always communicates with the oil inlet of the cylinder, an oil outlet hole which communicates with the lower part of the cylinder and its oil outlet, respectively. A communication opening is provided in the plunger body, and a check valve is used to allow hydraulic oil to move in one direction between an oil inlet hole and an oil outlet hole in the plunger body. The oil outlet of the cylinder is configured such that the range of communication changes when the shaft is rotated with respect to the oil outlet of the plunger body; A four-stroke engine characterized by a hole having a zero shape that tapers almost diagonally upward. 2. Claim 1, characterized in that the plunger body has a concave portion near the oil outlet hole so that the oil inlet hole always maintains communication with the oil inlet even during relative movement with the cylinder. 4-stroke engine described in section. 3. Claim 1, characterized in that the urging spring of the plunger body is strong enough to substantially return the plunger when not acted on by the rocker arm, or has a strength lower than that of the valve spring. 4-stroke engine. 4. The four-stroke engine according to claim 1, wherein the transmission mechanism is a linked rod rotation mechanism.