JPH0578906U - Engine intake / exhaust valve hydraulic drive - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides an intake / exhaust valve hydraulic drive system for an engine, in which the valve opening / closing timing can be adjusted as necessary to improve the engine drive efficiency. [Structure] In an oil sump chamber 26 in which a hydraulic chamber 26a is continuously provided,
The plunger 21 is housed so that it can move back and forth, and a return spring 23 that biases the plunger in the return direction and a cam mechanism 24 that forcibly moves the tip of the plunger into the hydraulic chamber to generate hydraulic pressure are provided. The generated hydraulic pressure is guided to the intake valve 9 or the exhaust valve via the hydraulic system path 8 and is supplied to the plunger.
An oil supply hole passage 27 that opens to a predetermined portion of the tip end surface and the peripheral surface is provided, and a control sleeve 28 is movably fitted to the peripheral surface of the plunger so that the plunger peripheral surface opening 27b of the oil supply hole passage is formed.
The plunger is provided with a spill port 29, and a sleeve position adjusting mechanism 31 for holding the position of the control sleeve and setting the position of the control sleeve with respect to the plunger is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an intake / exhaust valve hydraulic drive system for an engine that generates hydraulic pressure to open / close an intake valve and an exhaust valve of the engine.

[0002]

[Prior Art]

 As shown in FIG. 6, conventionally, a device that hydraulically drives an intake valve and an exhaust valve of an engine is used.

The apparatus body 1 is provided with a plunger 4 which is vertically driven by a cam 3 which constitutes a cam mechanism 2. That is, the plunger 4 is moved up by the cam mechanism 2, and the plunger 4 is moved down by the elastic force of the return spring 5 inserted between the apparatus body 1 and the cam contact portion 4a of the plunger 4.

The upper end of the plunger 4 projects from the upper surface of the apparatus body 1 and is inserted into a hydraulic chamber 6 provided therein. The oil filled in the hydraulic chamber 6 communicates with a hydraulic pressure introducing chamber 7 formed on the engine main body E side via a hydraulic system passage 8. In the hydraulic pressure introducing chamber 7, a hydraulic pressure receiving portion 9b formed at an upper end portion of a stem portion 9a, which is shown here as an intake valve 9, is accommodated in a freely displaceable manner without oil leakage.

Then, the cam mechanism 2 operates at a predetermined rotation speed, and the plunger 4 is vertically driven. In particular, as the plunger 4 rises, the oil storage volume of the hydraulic chamber 6 decreases and the oil filled therein is pressurized.

That is, hydraulic pressure is generated, guided to the hydraulic pressure introducing chamber 7 via the hydraulic system passage 8, and the hydraulic pressure is applied to the hydraulic pressure receiving portion 9 b of the intake valve 9. The intake valve 9 moves downward against the elastic force of the valve spring 10, and the valve portion 9c is separated from the valve seat 11 to open the intake port 12. Fresh air is supplied into the cylinder 13 and is burned as the piston 14 is driven upward.

When the plunger 4 moves down, the hydraulic pressure in the hydraulic chamber 6 decreases and the hydraulic pressure in the hydraulic pressure introducing chamber 7 decreases. The valve spring 10 raises and returns the intake valve 9, and the valve seat 11 is closed. That is, the intake stroke ends. Thereafter, the intake valve 9 is moved up and down, and the intake port 12 is opened and closed, as the plunger 4 moves up and down once. Here, also on the exhaust valve side not shown, a similar valve hydraulic drive device opens and closes the exhaust port.

[0008]

[Problems to be solved by the device]

 By the way, in such a device that opens and closes the intake valve and the exhaust valve on the engine side by the hydraulic pressure, the timings at which the intake and exhaust valves open and close their respective ports are fixed.

That is, the hydraulic pressure is generated as the plunger moves up, and the intake / exhaust valve suction / exhaust port opening timing is set. The hydraulic pressure disappears as the plunger descends, and the intake / exhaust port closing timing is set. To be done. On the other hand, it is desirable that the opening / closing timing of the intake / exhaust valve can be adjusted.

As shown in FIG. 2, the relationship between the valve lift of the intake valve and the exhaust valve with respect to the engine crank angle is shown by the solid line in the figure, and they coincide with each other at the TDC (top dead center) position. It is considered that the opening and closing timings of the intake valve and the exhaust valve are changed as shown by the broken line in the figure.

FIG. 3A shows the air flow rate characteristic in the cylinder (cylinder) with respect to the crank angle on the intake valve side when the engine is in the low speed rotation state. Here, in the direction of rotation from BDC (bottom dead center), the hatched portion in the figure is the portion where air may flow backward from the inside of the cylinder to the intake port side.

If the intake valve is closed late, it coincides with the time when air may flow backward. Therefore, in the low speed rotation state, if the intake valve is closed early, that is, in a so-called early closing state, it is possible to prevent backflow from the inside of the cylinder to the intake port.

Further, as shown in FIG. 1B, in the high-speed rotation state, the supplied air has inertia so that backflow from the inside of the cylinder to the intake port is unlikely to occur. Therefore, the amount of supplied air can be increased by delaying the closing timing of the intake valve to bring it into a so-called delayed closing state. As shown in FIG. 4, by adjusting the opening timing of the exhaust valve, it is possible to reduce pump loss, which has the advantage of improving fuel efficiency.

As shown in FIG. 5, in the indicator diagram of a direct injection engine without supercharging, the pressure starts to ignite before the top dead center and the pressure starts to rise, and after the top dead center, combustion occurs near a predetermined crank angle. Maximum pressure. Here, by adjusting the opening / closing timing of the intake / exhaust valve, it is possible to eliminate various losses indicated by hatching in the figure.

The present invention has been made in view of the above circumstances, and an object thereof is to hydraulically drive an intake valve and an exhaust valve of an engine, and the valve opening / closing timing can be adjusted as necessary. In addition, the present invention provides an intake / exhaust valve hydraulic drive system for an engine capable of improving the drive efficiency of the engine.

[0016]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention is a drive device for applying an oil pressure to an intake valve and an exhaust valve of an engine to open and close an intake port and an exhaust port of a cylinder. A continuous oil reservoir is provided, and a return spring for elastically urging the plunger to move in the return direction is accommodated in the oil reservoir. It is equipped with a cam mechanism that presses and urges the plunger against the return force of the return spring to forcibly move the tip of the plunger to the hydraulic chamber to generate hydraulic pressure, which is generated in the hydraulic chamber by the operation of this cam mechanism. This hydraulic pressure is guided to the intake valve or exhaust valve via a hydraulic system path to obtain these opening / closing operations, and one end of the plunger is opened at this tip surface and the other end is opened at a predetermined portion on the circumferential surface. An oil hole passage is provided, and a control sleeve is movably fitted to the plunger peripheral surface along the axial direction of the plunger so that the opening of the plunger peripheral surface of the oil supply passage can be opened and closed. Depending on the position, a spill port is provided to release the hydraulic pressure in the hydraulic chamber through the oil supply hole when it communicates with the peripheral surface opening of the oil supply hole. The intake / exhaust valve hydraulic drive system for an engine is provided with a sleeve position adjusting mechanism for setting the position.

[0017]

[Action]

 With the above-described structure, when the sleeve position adjusting mechanism adjusts the position of the control sleeve, the timing at which hydraulic pressure is actually generated by closing the opening end of the oil supply hole passage on the peripheral surface of the plunger is different. That is, the opening / closing timing of the intake / exhaust valve can be adjusted.

[0018]

【Example】

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

The intake / exhaust valve hydraulic drive system shown in FIG. 1 will be described later. Since the engine body E side is exactly the same as that described above with reference to FIG. 6, the same numbers are given and a new description is omitted.

The intake / exhaust valve hydraulic drive system has a spring chamber 23 in the device body 20 for supporting the plunger 21 so as to be vertically movable and accommodating the return spring 22. The return spring 22 is interposed between the cam receiving portion 21a, which is the lower end of the plunger 21, and the upper end of the spring chamber 23, and elastically biases the plunger 21 so as to drive it downward.

Further, the cam receiving portion 21a of the plunger 21 is in contact with the cam 25 constituting the cam mechanism 24 provided outside the apparatus main body 20 and is driven to move up like the conventional one. is there. That is, the plunger 21 is driven upward by the cam mechanism 24 and is driven downward by the elastic force of the return spring 22.

The upper end portion of the plunger 21 projects from the upper surface of the apparatus main body 20 and is inserted into the oil reservoir chamber 26 provided therein. An oil pressure chamber 26a having a smaller capacity than that of the oil sump chamber 26 is integrally connected to the upper end portion of the oil sump chamber 26, and the upper end portion of the plunger 21 extends to this point. The hydraulic chamber 26a communicates with the hydraulic pressure introducing chamber 7 on the engine body E side through a hydraulic system passage 8.

An oil supply hole passage 27 is provided in a portion of the plunger 21 accommodated in the oil sump chamber 26. One end opening portion 27 a of the oil supply hole passage 27 is opened at an upper end surface which is a tip end of the plunger 21, and the other end opening portion 27 b is opened at a peripheral surface fixed portion of the plunger 21.

The oil supply hole passage 27 is bored from the one end opening portion 27a along the central axis of the plunger 21, is bent in the circumferential direction at a predetermined portion, and communicates with the other end opening portion 27b. Is.

Further, an annular control sleeve 28 is fitted on the circumferential surface of the plunger 21 so as to be movable along the axial direction of the plunger 21. The control sleeve 28 is provided with a spill port 29 penetrating from the inner peripheral surface to the outer peripheral surface.

That is, depending on the position of the plunger 21, the control sleeve 28 does not face the peripheral surface opening 27b of the oil supply hole passage 27 but opens it or closes the peripheral surface opening 27b. Alternatively, the peripheral surface opening 27b faces the spill port 29 and opens.

Further, an engaging recess 30 is provided on the peripheral surface of the control sleeve 28, and the operating rod 32 a of the control rod 32 constituting the sleeve position adjusting mechanism 31 engages with the engaging recess 30. The control rod 32 extends to the outside of the oil sump chamber 26, and is connected to a stepping motor 33, which is a drive source here.

The motor 33 is also electrically connected to a control circuit 34 such as a CPU, and the control circuit 34 receives a rotation speed detection signal from a sensor 35 that detects the rotation speed of the engine and stores it in advance. A control signal is output to the motor 33 so as to adapt to the ideal operating conditions.

Then, the cam mechanism 24 operates at a predetermined rotation speed, and the plunger 21 is driven upward. In a state where the plunger peripheral surface opening 27b of the oil supply hole passage 27 does not face the control sleeve 28, the oil in the hydraulic chamber 26a flows backward from the upper end opening 27a of the oil supply hole passage 27 to the peripheral surface opening 27b, and no oil flows. No hydraulic pressure is generated.

When the plunger 21 continues to be lifted up through a so-called pre-stroke process, the control sleeve 28 closes the peripheral surface opening 27 b of the oil supply hole passage 27. Here, the hydraulic pressure is generated in the hydraulic chamber 26a for the first time, is guided to the hydraulic pressure introducing chamber 7 via the hydraulic passage 8, and the hydraulic pressure is applied to the hydraulic pressure receiving portion 9b of the intake valve 9.

The intake valve 9 moves downward against the elastic force of the valve spring 10, and the valve portion 9 c separates from the valve seat 11 to open the intake port 12. Fresh air is supplied into the cylinder 13 and is burned as the piston 14 is driven upward.

When the plunger 21 further rises, the peripheral opening 27 b of the oil supply passage 27 faces the spill port 29 of the control sleeve 28. The hydraulic chamber 26a and the oil sump chamber 26 communicate with each other through the oil supply hole passage 27 and the spill port 29 so that hydraulic pressure is not generated.

The oil pressure is not applied to the oil pressure receiving portion 9b of the intake valve 9, and the valve spring 10 causes the intake valve 9 to return to the elevated position. The valve seat 11 of the intake port 12 is closed, and the intake stroke ends. Such an action is exactly the same on the exhaust valve side.

Further, the engine speed is detected by the sensor 35, and the signal is sent to the control circuit 34 to drive the stepping motor 33 at the optimum angle. The control rod 32 drives the control sleeve 28 up and down by the instructed amount and holds its position. As described above with reference to FIGS. 2 to 5, the opening / closing timing of the intake valve 9 and the opening / closing timing of the exhaust valve according to the engine speed are adjusted.

That is, when the control sleeve 28 moves upward from the standard position and is held by the adjusting operation of the sleeve position adjusting mechanism 31, the timing of applying hydraulic pressure becomes slow. When the control sleeve 28 moves downward from the standard position and is held, the timing at which hydraulic pressure is applied is advanced. In any case, since the hydraulic pressure is applied for the same time, there is no change in the lift amount of each valve. The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the scope of the present invention.

[0036]

[Effect of the device]

 As described above, according to the present invention, the control sleeve is fitted on the plunger circumferential surface and movably along the axial direction of the plunger so that the opening of the plunger circumferential surface of the oil supply passage can be opened and closed. The sleeve is provided with a spill port that releases the oil pressure of the hydraulic chamber through the oil supply passage when it communicates with the peripheral opening of the oil supply passage according to the position of the plunger. Since it has a sleeve position adjustment mechanism that sets the position with respect to the plunger of the engine, the opening and closing timing can be adjusted as necessary to improve the engine driving efficiency in the case of hydraulically driving the intake valve and exhaust valve of the engine. The effect that can be achieved is achieved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an intake / exhaust valve hydraulic drive system for an engine, showing an embodiment of the present invention.

FIG. 2 is a characteristic diagram of a valve lift with respect to a crank angle of an intake valve and an exhaust valve.

FIG. 3A is an operating characteristic diagram of the intake valve when the engine rotates at a low speed. (B) is an operating characteristic diagram of the intake valve when the engine rotates at a high speed.

FIG. 4 is an indicator diagram according to the opening / closing timing of an exhaust valve.

FIG. 5 is an indicator diagram showing various losses.

FIG. 6 is a schematic configuration diagram of an intake / exhaust valve hydraulic drive system for an engine, showing a conventional example of the present invention.

[Explanation of symbols]

9 ... Intake valve, 12 ... Intake port, 20 ... Device body, 26
a ... hydraulic chamber, 26 ... oil reservoir, 21 ... plunger, 2
3 ... Return spring, 24 ... Cam mechanism, 8 ... Hydraulic system path, 27 ...
Refueling hole passage, 27a ... (upper end opening portion of refueling hole passage), 27b
... Circumferential surface opening (of oil supply passage), 28 ... Control sleeve, 29 ... Spill port, 31 ... Sleeve position adjusting mechanism.

Claims (1)

[Scope of utility model registration request] 1. In a drive device for applying an oil pressure to an intake valve and an exhaust valve of an engine to open and close an intake port and an exhaust port of a cylinder, a device main body and a hydraulic chamber provided in the device main body are integrally connected. Oil reservoir chamber, a plunger which is housed in the oil reservoir chamber and whose tip portion is movable back and forth in the hydraulic chamber, a return spring which elastically biases the plunger to move in the return direction, and the return spring. The cam mechanism that presses and urges the plunger against the restoring force of the plunger to forcibly move the tip of the plunger to the hydraulic chamber to generate hydraulic pressure, and the hydraulic pressure generated in the hydraulic chamber by the operation of the cam mechanism as described above. A hydraulic passage for guiding the intake valve or the exhaust valve to open and close them, and an oil supply passage for the plunger, one end of which opens at this tip surface and the other end of which opens at a predetermined portion of the circumferential surface. A control sleeve that is movably fitted to the circumferential surface of the plunger along the axial direction of the plunger to open and close an opening of the circumferential surface of the plunger of the oil supply hole passage; and a control sleeve provided on the control sleeve depending on the position of the plunger. From the spill port that releases the oil pressure of the hydraulic chamber through the oil supply hole passage when it communicates with the peripheral surface opening, and the sleeve position adjustment mechanism that holds the position of the control sleeve and sets the position of the control sleeve with respect to the plunger. A hydraulic drive system for intake and exhaust valves of an engine.