JPH05202707A - Valve system of engine - Google Patents

Abstract

PURPOSE:To eliminate almost the influence exerted on an actuator from engine vibration so as to improve the reliability of valve operation. CONSTITUTION:The valve system of an engine is provided with a first cylinder 2 provided outside the engine, a second cylinder 3 provided on the cylinder block 60 of the engine, a first piston 53 provided in the cylinder 2 slidably, a plunger 57, and a laminated piezoelectric element 56 by which the piston 53 is reciprocating-driven in its sliding direction. The plunger 57 is provided in such a way that it is capable of making reciprocating motion along the longitudinal direction of the cylinder 3 in its condition in which the one end of the plunger 57 is faced to the inside of the cylinder 3, and the other end thereof is faced to the outside, and also an intake valve 58 is provided integratedly on the other end side thereof. The cylinder 2 is connected to the cylinder 3 through a hose 4, and also oil 10 is filled into the hose 4 and the cylinders 2, 3 communicated with the hose 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine valve operating system, and more particularly to an engine valve operating system in which an intake valve or an exhaust valve is opened and closed by remote control.

[0002]

BACKGROUND ART Conventionally, an engine intake or exhaust valve is
It was common to open and close mechanically using a cam mechanism driven by the engine. However, when mechanically opening and closing the valve by the cam mechanism, the mechanical resistance of the engine increases. Therefore, it is not a good idea in terms of the output characteristics of the engine. Therefore, in recent years, there has been a tendency to employ a so-called electric valve mechanism that directly opens and closes a valve by using an electric drive means such as a solenoid (for example, JP-A-58-
183805). However, in the case where the valve is directly opened and closed by an electric drive means such as a solenoid as in this known example, the electric drive means has a larger operation amount due to its operation characteristic because of its operation characteristic. However, the valve lift amount cannot be increased, and as a result, the intake and exhaust characteristics of the engine deteriorate.

In order to solve such a problem, recently, a non-compression is provided between an intake or exhaust valve of an engine and an electric drive means (comprising a piezoelectric element) for electrically driving the valve to open and close. Various valve operating devices for engines have been proposed in which a displacement amplifying mechanism using a sexual fluid is interposed to amplify the displacement of an electric drive means and transmit the displacement to the valve side.

FIG. 1 shows an example of a valve train of this type, which the applicant has previously filed. Valve operating device 51 of this figure
Is for opening and closing an intake port (not shown).

In the valve gear 51, when the engine is stopped,
A cylinder 52 that constitutes the valve gear 51 (this cylinder 5
2 is fixed on the cylinder block 60. When the laminated piezoelectric element 56 mounted in the first chamber 54 of No. 1) is not displaced, the pressure does not act on the oil in the second chamber 55, so the intake valve 58 (and the plunger 57) is a compression coil spring. It is held in its original position by 63 and is in a closed state. When the engine is started and the laminated piezoelectric element 56 is energized by the engine control unit (hereinafter abbreviated as “ECU”) 50, each piezoelectric element 56A forming the laminated piezoelectric element 56 extends in the axial direction. The laminated piezoelectric element 56 generates displacement in the arrow B direction, and the first piston 53 is driven in the arrow B direction. At this time, the first piston 53 applies pressure to the oil in the second chamber 55,
The pressure of this oil causes the plunger 57 to move in the direction of the arrow B, and the intake valve 58 is opened via the plunger 57. FIG. 4 shows a maximum valve lift state in which the plunger 57 is moved and the intake valve 58 is fully opened. In this case, the displacement of the laminated piezoelectric element 56 is amplified according to the ratio of the thickness receiving area of the first piston 53 and the plunger 57 and is transmitted to the intake valve 58. Therefore, for example, even if the displacement amount of each piezoelectric element 56A constituting the laminated piezoelectric element 56 is on the order of microns, the movement amount of the intake valve 58, that is, the valve lift amount can be set on the order of millimeters.

On the other hand, when the energization is stopped by the ECU 50, each piezoelectric element 56A which constitutes the laminated piezoelectric element 56.
Returns to its original shape. Therefore, the first piston 53 moves from the position of FIG. 4 in the direction of arrow A and returns to the original position (the state of FIG. 3). Therefore, the hydraulic pressure in the second chamber 55 suddenly becomes a negative pressure, and the intake valve 58 returns to the original position. In this way, the intake valve 58 is reciprocally driven in the directions of arrows A and B, so that the intake valve 58 is opened and closed.

When the oil leaks from the oil seal 91 or 92 during use and the pressure of the oil in the second chamber 55 falls below a specified value, the intake valve 58 is not lifted and the oil supply not shown is shown. Means to oil passage 9
The check valve 72 is opened by the pressure of the oil flowing into the second passage 70, and the second passage portion 70B that constitutes the passage 70 dedicated to supplying the working fluid,
Oil is replenished through the lower lift check groove 66 and the first passage portion 70A. (Here, the amount of replenished oil is a small amount of oil leaked from the oil seal.)
On the other hand, when excessive oil is supplied into the second chamber 55 for some reason and the hydraulic pressure in the second chamber 55 becomes slightly higher than the regulation, the plunger 57 moves down to the position shown in FIG. At this time, the oil in the second chamber 55 passes through the first passage portion 80A, the upper lift check groove 65, and the second passage portion 80B that form the oil discharge dedicated passage 80, and the check valve 71 is caused by the pressure of the oil. When opened, excess oil is quickly discharged, and the hydraulic pressure in the second chamber 55 reaches a specified value.
In this way, the amount of oil in the second chamber 55 is always kept almost constant.

[0008]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
According to the above, the displacement of the laminated piezoelectric element 56 is determined by the first piston 5
3 and the pressure-receiving area of the plunger 57 can be amplified and transmitted to the intake valve (hereinafter referred to as “valve” in the description of this section) 58, so that energization start / energization stop of the laminated piezoelectric element 56 can be performed. By appropriately controlling using the ECU 50, it becomes possible to open and close the valve 58 at a desired timing according to the operating condition of the engine.
Since the opening and closing of the valve are performed by hydraulic pressure, the operation response is improved, the smooth operation of the valve 58 can be ensured even at the time of high engine rotation, and the upper lift check groove 65 and the lower lift can be secured. Due to the action of the check groove 66, the working fluid supply passage 70, and the working fluid discharge passage 80, there is a shortage of oil in the second chamber 55 of the cylinder 52 over time.
Alternatively, if an excess occurs due to some reason, the oil is quickly replenished and discharged, and the oil amount can be kept almost constant at all times, which makes it possible to keep the valve lift amount constant. There are advantages. But,
As a result of subsequent research, in the valve operating device 51, as in other valve operating devices for engines that employ a displacement amplifying mechanism using an incompressible fluid (Japanese Patent Laid-Open No. 61-58909, etc.), valve driving means is used. The laminated piezoelectric element (hereinafter, in the explanation of this section,
It is called an "actuator". ) Is the intake valve (or exhaust valve)
The cylinder head becomes heavier by the weight of the actuator because it is installed on the upper part of the engine. Also, since the actuator is directly attached to the engine, the reliability of its operation deteriorates over time due to the influence of engine vibration, etc. It turned out that there is a possibility that the inconvenience may occur. Also,
When there are a plurality of intake valves and a plurality of exhaust valves as in a four-valve engine, it is necessary to provide as many actuators as there are valves, which perform the same operation.

[0009]

SUMMARY OF THE INVENTION The present invention has been made under the above-mentioned circumstances, and an object thereof is to reduce the influence of engine vibration on an actuator and to improve the reliability of valve operation. At the same time, another object of the present invention is to provide a valve operating system for an engine that can simultaneously open and close a plurality of valves by using one actuator.

[0010]

In order to achieve the above object, the valve gear of the present invention is a first valve provided outside the engine.
Cylinder, one or more second cylinders provided in the cylinder block portion of the engine, a first piston slidably mounted on the first cylinder, and one end inside the second cylinder. A second cylinder that is reciprocally movable along the longitudinal direction of the second cylinder with the other end facing the outside and that has an intake valve or an exhaust valve integrally provided on the other end side. Of the first piston and an actuator that reciprocally drives the first piston in the sliding direction, connects the first cylinder and the second cylinder with a tubular member, and connects the tubular member and the first member. , The second cylinder is filled with an incompressible working fluid.

[0011]

When the actuator is not displaced while the engine is stopped, pressure does not act on the working fluid, so that the valve is held by the appropriate original position holding means and is in a closed state. When the engine is started and the actuator is displaced in a predetermined valve opening direction to drive the first piston in the first cylinder in that direction, the first piston applies pressure to the working fluid, and this fluid pressure is By acting on the pressure receiving surface of the second piston in the second cylinder via the tubular member,
The valve moves (lifts) integrally with the piston. In this case, the actuator displacement is
It is adapted to be amplified and transmitted to the valve according to the ratio of the areas of the first piston and the second piston. On the other hand, when the actuator is displaced in the valve closing direction opposite to the front and drives the first piston in that direction, the fluid pressure of the working fluid in the first and second cylinders and the tubular member suddenly becomes negative pressure,
The valve returns to its original position. In this way, the displacement of the actuator in the first cylinder provided at a position distant from the engine is transmitted via the hydraulic pressure to the second piston integrally provided with the intake valve or the exhaust valve of the engine. So
Actuator operation is not easily affected by engine vibration.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to FIGS. Here, the same reference numerals will be given to the same or equivalent components as those of the conventional example in the above-mentioned drawings.

FIG. 1 shows an intake valve operating system 1 for opening and closing an intake port (not shown). The valve gear 1 includes a first cylinder 2 provided outside the engine,
The second cylinder 3 provided in the cylinder block 60 of the engine, the first piston 53 slidably mounted on the first cylinder 2, and one end inside the second cylinder 3 (upper end in the figure) With the other end (the lower end in the figure) facing the outside so as to be reciprocally movable along the longitudinal direction of the second cylinder 3, and an intake valve 58 is integrally provided on the other end side. And a laminated piezoelectric element 56 as an actuator that reciprocally drives the first piston 53 in its sliding direction. And the first cylinder 2 and the second
Is connected to the cylinder 3 by a hose 4 as a tubular member, and oil as an incompressible working fluid is provided inside the hose 4 and the first and second cylinders 2 and 3 communicating with the hose 4. 10 are filled.

This will be described in more detail. First cylinder 2
1 is a bottomed cylindrical member whose lower end in FIG. 1 is fully opened and whose upper end is closed except for the central portion, and which is mounted at a predetermined distance from the engine with the lower end opening closed. It is fixed on the member 5. The peripheral edge of the opening at the center of the upper end surface of the first cylinder 2 is provided to project outward, and one end of the hose 4 is connected to the projecting portion 2A via a connecting member 6. As described above, the first piston 53 is slidably mounted inside the first cylinder 2, and one end (upper end in the figure) is provided between the first piston 53 and the mounting member 5. Is fixed to the lower surface of the first piston 53, and the other end (lower end in the figure)
The laminated piezoelectric element 56 described above fixed to the upper surface of the mounting member 5 is interposed. In this laminated piezoelectric element 56,
The ECU 50 is connected, and the ECU 50 controls the energization timing and the energization time according to the operating state of the engine.

The second cylinder 3 is composed of a somewhat thick cylindrical member, and is fixed on the cylinder block 60 with one end (lower end in the drawing) of the engine being blocked by the cylinder block 60. The other end (upper end in the figure) of the second cylinder 3 is closed at the center by a hose mounting member 7 which also functions as a lid member having an opening having substantially the same diameter as the hose 4. The other end of the hose 4 is connected to the projecting end of the hose mounting member 7 via a connecting member 8. Further, the second cylinder 3 is equipped with the plunger 57 as described above, and the plunger 57 is provided along the guide member 9 provided in the state of penetrating the cylinder head 60, with arrow A, It can move back and forth in the B direction. This plunger 57
The intake valve 58 provided on the other end side is actually provided at a position where the inlet of the intake port (not shown) on the cylinder block 60 side can be opened and closed. And the plunger 57
The intake valve 58 is urged in the direction of arrow A in the drawing by a compression coil spring 63 provided between the spring retainer 12 fixed to the upper end portion of the plunger 57 in FIG. 1 and the guide member 9. .. Here, the state of FIG. 1 shows a state where the compression coil spring 63 is maximally extended and the valve lift is zero.

Further, in this embodiment, an upper lift check groove 65 and a lower lift check groove 66 are formed on the outer peripheral portion of the plunger 57 along the longitudinal direction at predetermined intervals.
These lift check grooves 65 and 66 are provided in the plunger 57.
1 and a position where the valve lift is zero as shown in FIG. 1 and a position where the valve lift is maximum (not shown), the working fluid supply passage 70 for connecting the inside of the second cylinder 3 to the outside is operated. A fluid discharge passage 80 is provided. The working fluid discharge passage 80 has a U-shaped first passage portion 8 extending from the inside of the second cylinder 3 to the inner peripheral surface of the guide member 9 through a part of the peripheral wall of the cylinder 3.
0A and the first passage portion 80A via the plunger 57.
The guide member 9 and the L-shaped second passage portion 80B formed on the peripheral wall of the second cylinder 3 at the corresponding positions on the opposite side. Then, the second passage portion 80
A first check valve 71 that allows only the flow of oil from the passage portion 80B side to the outside and blocks the flow in the opposite direction is provided at the lower left end of the drawing of B. Similarly, the working fluid supply-only passage 70 has a U-shaped first passage portion 70A extending from the inside of the second cylinder 3 to the inner peripheral surface of the guide member 9 through a part of the peripheral wall of the cylinder 3, It is configured to include a guide member 9 at a corresponding position on the opposite side of the first passage portion 70A via the plunger 57 and an L-shaped second passage portion 70B formed on the peripheral wall of the cylinder 3. A second check valve 72 that allows only the flow of oil from the outside to the side of the passage 70B and blocks the flow in the opposite direction is provided at the lower left end of the second passage 70B in the figure. Has been. An oil passage 90 connected to an oil supply unit (engine hydraulic pressure) not shown is provided in the cylinder block 60 outside the check valves 71 and 72.
Is provided.

In FIG. 1, reference numerals 91 and 92 denote oil seals.

In the valve operating system 1 of the present embodiment thus constructed, when the laminated piezoelectric element 56 is not displaced while the engine is stopped, the first and second cylinders 2 and 3 and the hose 4 are arranged. Since no pressure acts on the oil 10 inside, the intake valve 58 (and the plunger 57) is held in the original position by the compression coil spring 63 and is in a closed state. When the engine is started and the laminated piezoelectric element 56 is energized by the ECU 50, each piezoelectric element 56A forming the laminated piezoelectric element 56 extends in the axial direction and the laminated piezoelectric element 56 is indicated by an arrow A.
A displacement is generated in the direction, and the first piston 53 is driven in the direction of arrow A. At this time, the first piston 53 applies pressure to the oil 10, and the pressure of the oil 10 causes the plunger 57 to move in the direction of arrow B, and the intake valve 8 is opened via the plunger 57. In this case, the displacement of the laminated piezoelectric element 56 is similar to that of the valve operating device 51 described above, and the first piston 53 and the plunger 57 are displaced.
Are amplified and transmitted to the intake valve 58 according to the ratio of the pressure receiving area of the piezoelectric element 56. Similarly, for example, even if the displacement amount of each piezoelectric element 56A forming the laminated piezoelectric element 56 is in the order of microns. The moving amount of the intake valve 58, that is, the valve lift amount can be set to the millimeter order.

On the other hand, when the energization is stopped by the ECU 50, each piezoelectric element 56A which constitutes the laminated piezoelectric element 56.
Returns to its original shape. Therefore, the first piston 53 moves in the direction of arrow B and returns to the original position (the state of FIG. 1). Therefore, the oil pressure of the oil 10 inside the first and second cylinders 2 and 3 and the hose 4 suddenly becomes a negative pressure, and the intake valve 58 returns to the original position. In this way, the intake valve 58 is controlled by the arrows A and B.
The intake valve 58 is opened and closed by being reciprocally driven in the direction.

When the oil 10 leaks from the oil seal 91 or 92 during use and the pressure of the oil 10 inside falls below a specified value, the intake valve 58 is not lifted and the oil supply means (not shown) Check valve 72 is opened by the pressure of the oil in
Second passage portion 70B that constitutes the lower lift check groove 6
6, oil is replenished through the first passage portion 70A.
(Here, the amount of oil to be replenished is a small amount of oil leaked from the oil seal.) On the other hand, if excessive oil is supplied for some reason and the hydraulic pressure becomes somewhat higher than the specified value, When the plunger 7 descends to the valve lift maximum position, the oil 10 passes through the first passage portion 80A, the upper lift check groove 65, and the second passage portion 80B which form the oil discharge dedicated passage 80, and the oil 10 10
The check valve 71 is opened by the pressure of 1, the excess oil is quickly discharged, and the hydraulic pressure becomes the specified value. In this way, in this embodiment, the oil 1 inside the first and second cylinders 2 and 3 and the hose 4 is similar to the valve operating device 51 described above.
The amount of 0 is always kept almost constant.

As described above, according to this embodiment,
Since the laminated piezoelectric element 56 serving as an actuator is provided via the hose 4 at a location distant from the engine, the vibration of the engine hardly affects the laminated piezoelectric element, and the intake valve 58 by the laminated piezoelectric element 56. Since the reliability of the opening / closing control is improved and the laminated piezoelectric element 56 is not provided in the cylinder head portion, the weight of the cylinder head can be reduced accordingly.

In the case of a four-valve engine having two intake valves, these two intake valves 5 are used as in the application example shown in FIG.
8 and 58 are provided in the second cylinders 3 and 3, respectively, and the hoses 4A and 4 are provided in the second cylinders 3 and 3, respectively.
B is connected to one end thereof, and the other ends of the hoses 4A and 4B are connected to the other end of the bifurcated connecting member 11 as shown in the drawing, in which one end of the hose 4C is connected to the other end thereof. However, if the other end of the hose 4C is connected to the first cylinder 2, the intake valves 58, 58 can be simultaneously opened and closed by the single laminated piezoelectric element 56. Therefore, since it is not necessary to provide an actuator such as the laminated piezoelectric element 56 for each valve, it is possible to reduce the weight and the cost.

Further, most of the above-mentioned embodiment has the same structure as the valve operating device 51 described above, and therefore has the same advantages. That is, the opening / closing timing of the intake valve 58 and the like can be controlled by the ECU 50 according to the operating condition of the engine and at a desired timing, and the opening / closing timing of the intake valve 58 can be easily changed and set by changing the program of the software of the ECU. Further, since the displacement of the laminated piezoelectric element 56 is amplified and the intake valve 58 is driven, and the intake valve 58 is opened and closed by hydraulic pressure, the operation response is improved and the engine response is improved. It is possible to ensure the smooth operation of the intake valve 58 even at the time of high rotation,
Further, since the upper lift check groove 65, the lower lift check groove 66, the fluid supply dedicated passage 70, and the fluid discharge dedicated passage 80 provided in the plunger 57 keep the amount of oil inside substantially constant, Even if the oil leaks from the oil seal part over time or if excessive oil is temporarily supplied for some reason,
The valve lift amount can be kept constant, the same good valve operating condition as in the initial stage can be maintained for a considerably long period of time, and intake performance deteriorates due to valve malfunction over time. Can be effectively suppressed.

Although the valve operating device for opening and closing the intake valve has been described in the above embodiment, it is needless to say that the present invention can be similarly applied to the opening and closing of the exhaust valve. The case where the laminated piezoelectric element is used as the actuator has been illustrated, but the present invention is not limited to this, and a solenoid or a conventional camshaft may be used as the actuator.

[0025]

Since the present invention is constructed and functions as described above, according to the present invention, the displacement of the actuator in the first cylinder provided at a location distant from the engine is taken by the intake air of the engine via hydraulic pressure. Since the valve or exhaust valve is transmitted to the second piston integrally provided, the operation of the actuator is less likely to be affected by engine vibration. Therefore, the reliability of the opening / closing control of the intake valve or the exhaust valve by the actuator is reliable. Since the property is improved and the actuator is not provided in the cylinder head portion, the weight of the cylinder head can be reduced correspondingly.
As explained in the application example of, since it is possible to simultaneously open and close multiple valves with one actuator,
It is not necessary to provide an actuator for each valve, and it is possible to provide an excellent engine valve operating system that has not existed in the past, which can achieve further weight reduction and cost reduction.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an application example of the embodiment of FIG.

FIG. 3 to FIG. 4 are views for explaining the valve operating device previously filed.

[Explanation of symbols]

 1 Valve Operating Device 2 First Cylinder 3 Second Cylinder 4 Hose as Tubular Member 10 Oil as Incompressible Working Fluid 53 First Piston 56 Laminated Piezoelectric Element as Actuator 57 Plunger as Second Piston 58 intake valve

Claims (1)

[Claims] 1. A first cylinder provided outside the engine, and a first cylinder provided in a cylinder block portion of the engine.
Alternatively, two or more second cylinders, a first piston slidably mounted on the first cylinder, and a state in which one end faces the inside of the second cylinder and the other end faces the outside. And a second piston that is reciprocally movable along the longitudinal direction of the second cylinder and has an intake valve or an exhaust valve integrally provided at the other end side, and the first piston that slides the second piston. An actuator that is reciprocally driven in the moving direction, connects the first cylinder and the second cylinder by a tubular member, and connects the tubular member and the first and second cylinders communicating with the tubular member with each other. An engine valve operating system characterized by being filled with a compressible working fluid.