JPH0788765B2 - Hydraulic drive control device for intake valve - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device, and more particularly to a drive control device that controls an intake valve lift amount, timing, etc. of an engine.

[Prior Art] Conventionally, a hydraulic control valve for switching control of hydraulic pressure supply using a piezo actuator or a switching valve driven by a solenoid as disclosed in Japanese Utility Model Laid-Open No. 61-140105 is used. There has been one that controls the hydraulic pressure supplied to the cylinder provided in the intake valve to control the lift amount of the intake valve.

[Problems to be Solved by the Invention] However, in the conventional configuration as described above, for example, in a configuration using a switching valve driven by a solenoid, it may not be possible to follow the high speed drive of the intake valve, There was a problem that it was not possible to perform delicate control. Further, the lift amount of the intake valve is adjusted to form a vortex of intake air near the intake port.
Adjusting the so-called swirl, and controlling the hydraulic pressure in multiple stages to reduce ping-pong gloss,
Moreover, there has never been a high-speed control. The present invention has been found in view of the above points, and realizes high-speed hydraulic control with a high-speed followability using a piezo actuator, and highly accurate drive control of an intake valve by controlling pressure in multiple stages. The purpose is to do.

[Means for Solving the Problems] In order to achieve the above object, in the hydraulic drive control device of the present invention, a variable pressure chamber and a hydraulic chamber for temporarily holding a fluid are formed and intermittently pumped from a hydraulic pump. A passage for sequentially guiding an incoming fluid from an inlet port to the variable pressure chamber and the hydraulic chamber, a passage for guiding a fluid in the hydraulic chamber to an accumulator chamber for controlling a lift amount of an intake valve through an outlet port, and the hydraulic chamber And a housing provided with a relief port for relieving the fluid, and defining the variable pressure chamber while accommodating in the housing and expanding and contracting in accordance with the applied voltage to expand or reduce the volume of the variable pressure chamber. A piezo actuator, a control means for controlling the voltage applied to the piezo actuator, and a reciprocally movable member provided in the housing. A needle valve that receives pressure in the variable pressure chamber and the hydraulic chamber and connects or disconnects the hydraulic chamber and the relief port, and a fluid provided from the inlet port to the variable pressure chamber, the needle valve being provided between the inlet port and the variable pressure chamber. The first check valve for allowing the movement of the variable pressure chamber to prevent the movement of the fluid from the variable pressure chamber to the inlet port side, and provided in the middle of the passage connecting the variable pressure chamber and the hydraulic pressure chamber from the variable pressure chamber to the hydraulic pressure chamber. A second check valve that allows the movement of fluid to the hydraulic chamber and blocks the movement of fluid from the hydraulic chamber to the variable pressure chamber, when the fluid pressure in the variable pressure chamber is relatively higher than the fluid pressure in the hydraulic chamber. When the needle valve shuts off the hydraulic chamber and the relief port and the fluid pressure in the variable pressure chamber is relatively lower than the fluid pressure in the hydraulic chamber, the needle valve connects the hydraulic chamber and the relief port. The control means adopts a technical means that controls the energization and de-energization of the piezo actuator at a predetermined interval so that the oil in the hydraulic chamber is relieved and the hydraulic chamber is lowered to a predetermined pressure. Is.

[Operation and Effect] With the above configuration, the pressure oil supplied from the hydraulic pump is supplied to the variable pressure chamber via the first check valve, and to the hydraulic pressure chamber via the second check valve via the variable pressure chamber. Supplied.
Further, it is supplied from the hydraulic chamber to the accumulator chamber of the intake valve. Therefore, the pressure in the hydraulic chamber and the hydraulic pressure in the accumulator chamber rise as the pressure of the hydraulic pump rises, and the intake valve is driven according to this pressure. Even if the pressure pumping of the hydraulic pump is reduced, the pressure oil in the variable pressure chamber is sealed by the first check valve and the pressure oil in the hydraulic pressure chamber is sealed by the second check valve. The pressure in the accumulator chamber is kept constant. Therefore, the lift amount of the intake valve is also maintained at a predetermined position according to the pressure in the accumulator chamber. Next, when power supply to the piezo actuator is stopped and the pressure in the variable pressure chamber drops, the needle valve moves due to the differential pressure, the pressure oil in the hydraulic chamber relieves via the relief port, and the variable pressure chamber and hydraulic chamber The second check valve opens due to the differential pressure between the pressure and the pressure oil in the hydraulic chamber flows into the variable pressure chamber. Since the pressure in the accumulator chamber also decreases as the pressure in the hydraulic chamber decreases, the lift amount of the intake valve changes according to this pressure. When the piezo actuator is energized again, the needle valve blocks the communication between the hydraulic chamber and the relief port, so that the pressure oil in the hydraulic chamber and the accumulator is maintained at the pressure at the time when the piezo actuator was energized.

Therefore, since the pressure in the accumulator chamber can be appropriately set by controlling the energization of the piezo actuator, the intake valve can be driven and controlled at high speed, and the intake valve can be temporarily stopped.
It is possible to adjust the swirl effect and reduce pumping loss. It is also possible to reduce noise such as tapping noise when the valve is closed by slowing down the valve closing speed of the intake valve by repeatedly energizing and stopping the piezo actuator at high speed when the intake valve is closed. Become.

〔Example〕

A first embodiment of the present invention will be described below with reference to FIG. Reference numeral 1 denotes a hydraulic pump, which receives a driving force of an engine (not shown) and operates in synchronization with the engine. This pump does not have a normal metering mechanism and an oil distribution mechanism, but has a simple structure having only a mechanism capable of intermittently discharging a fixed amount of oil. Reference numeral 11 is a suction return valve for reducing the pressure in the pipe 14 after the oil in the pump chamber 12 is discharged by the plunger 13.

Reference numeral 2 denotes an intake valve drive section, which drives the intake valve 21 of the engine up and down in the drawing. The intake valve drive unit 2 is formed with an accumulator chamber 22 into which oil from the hydraulic pump 1 flows in and out, and the hydraulic pressure of the accumulator chamber 22 drives the piston 23 up and down. Further, a spring receiver is fixed to the intake valve 21, and is constantly urged by the spring 24 in the valve closing direction.

A hydraulic control valve 3 includes a piezo actuator 31 and a piezo holder 33 that holds a hydraulic piston 32.
The hydraulic control valve 3 is a valve housing that holds the needle valve 34, the first check valve 35, and the second check valve 36.
37, and a variable pressure chamber 38 is formed in the space between the hydraulic piston 32 and the valve housing 37. Further, a hydraulic chamber 39 is provided below the needle valve 34 in the valve housing 37, and a hydraulic port 40 for guiding the hydraulic pressure of the hydraulic chamber 39 to the intake valve drive unit 2 and the needle valve 34.
A relief port 41 for relieving the oil in the hydraulic chamber 39 when the valve is opened is also formed in the valve housing 34.

The needle valve 34 is biased by a spring 42 in the valve closing direction. An O-ring 43 is attached to the hydraulic piston 32 to keep the variable pressure chamber 38 oil-tight. Needle valve 34
Is slidably housed in the valve housing 37 while keeping airtightness, and the tip end portion is configured so that the hydraulic chamber 39 and the relief port 41 can be electrically connected and disconnected.

The piezo actuator 31 has, for example, a diameter of 15 mm and a thickness of 0.
5mm disk-shaped piezoelectric element and diameter 15mm, 0.01mm pressure copper plate is alternately laminated into a columnar shape, so that voltage can be applied in parallel in the thickness direction of each piezoelectric element, The lead wire, 311 and the copper plate are connected. The lead wire 311 extends to the outside of the piezo holder 33 via the grommet 312 and is connected to the electric circuit 100. For the piezoelectric element, for example, ferroelectric ceramics that is fired with lead zirconate titanate as the main component is used. This ferroelectric ceramic is a typical element having a piezo effect. As for the physical properties, when a voltage of 500 V is applied in the thickness direction, the thickness increases by 0.5 μm, and conversely, when a voltage of 500 V is generated, both ends are short-circuited to release the accumulated charge. The μm thickness is reduced. 200kg / cm ^{2 in the} thickness direction
When the pressure is applied, 200V is applied in the thickness direction due to the contraction.
Generate the voltage of. In this embodiment, the piezo actuator 31 has 100 piezoelectric elements electrically connected in parallel. Therefore, when a voltage of 500 V is applied, a total extension of 50 μm can be obtained. The hydraulic piston 32 moves up and down by such axial extension and contraction of the piezo actuator 31.

The oil discharged from the injection pump 1 via the suction return valve 11 enters the variable pressure chamber 38 via the first check valve 35. Furthermore, the structure is such that it is introduced into the hydraulic chamber 39, the hydraulic port 40, and the accumulator chamber 22 of the intake valve drive unit 2 via the second check valve 36.

Next, the operation will be described.

Since the pump 1 receives the driving force of the engine and rotates synchronously, the oil sucked into the pump chamber 12 is absorbed by the plunger 13
Is discharged into the pipe 14 through the suction return valve 12 at a predetermined timing. The oil flows into the variable pressure chamber 38 via the first check valve 35 of the hydraulic control valve 3 and pushes the hydraulic piston 32 upward. At the same time, oil flows into the hydraulic chamber 39, the pressure port 40, and the accumulator chamber 22 of the intake valve drive unit 2 via the second check valve 36. This hydraulic pressure causes the piston 22 to descend, and the intake valve 21 is pushed down and opened against the force of the spring 24. At this time, the needle valve
34 receives the valve closing force due to the hydraulic pressure of the variable pressure chamber 38 and the valve opening force due to the hydraulic pressure of the hydraulic pressure chamber 39.
Since the side is large, the valve is closed and the high-pressure oil from the pump 1 is sent to the intake valve 2.

FIG. 2 is a time chart showing the behavior of each part of the apparatus. 2 shows the mutual relationship between the lift of the intake valve 21 and the lift of the intake valve 21.

The piezo actuator 31 is energized and extended before the discharge of the hydraulic pump 1 is started. (Point A) Therefore, the oil from the hydraulic pump 1 flows into the variable pressure chamber 38 in the expanded state, and the pressure is applied to the piston actuator 31 via the hydraulic piston 32. Further, the pressure in the hydraulic chamber 39 increases as the plunger 13 rises in the discharge stroke of the hydraulic pump 1 as in the variable pressure chamber. When the discharge stroke of the hydraulic pump 1 is completed, the pressure in the pipe 14 is reduced by the suction return valve 11, but the pressure remains increased because of the first check valve 35 and the second check valve 36. At this time, since the intake valve 21 fills the accumulator chamber 22 with the fuel discharged from the hydraulic pump 1,
The valve 23 is lifted by the piston 23.

When the piezo actuator 31 is de-energized at the closing timing of the intake valve 21, the (B) point piezo actuator
31 contracts. Therefore, the volume of the variable pressure chamber 38 increases and the pressure decreases accordingly. (Point C) However, because of the second check valve, the hydraulic pressure in the hydraulic chamber 39 does not drop. (Point D) Therefore, only the valve closing force of the needle valve 34 by the variable pressure chamber 38 decreases,
The needle valve 34 opens. (Point E) In this state, if the energization of the piezo actuator 31 is stopped, the hydraulic pressure of the hydraulic chamber 39 decreases, the opening force of the needle valve 34 decreases, and the variable pressure chamber 38 and the hydraulic chamber 39 The needle valve closes when the hydraulic pressure is balanced. That is,
Needle valve before intake valve 21 is closed
It is possible that 34 will close the valve. In this embodiment, when the hydraulic pressure in the hydraulic chamber 39 drops to some extent, the piezo actuator 31 is energized again (point F) and then energized is stopped (point G).

When the piezo actuator 31 is energized again, (F
Point) Piezo actuator expands. Therefore, the pressure in the variable pressure chamber rises, and the oil in the variable pressure chamber 38 flows out to the hydraulic pressure chamber 39 side through the second check valve 36 until the pressure is balanced with the hydraulic pressure chamber 39 (point H). Therefore, the pressure in the hydraulic chamber 39 rises (I
point). Also, the needle valve is closed. (J point) After this,
When the energization of the piezo actuator 31 is stopped (point G), the piezo actuator 31 contracts as in the previous case, and
The operation in which the oil pressure at 38 decreases (point K) and the needle valve 34 opens (point L) is repeated. By repeating this, the hydraulic pressure in the accumulator chamber 22 decreases. By controlling the timing and interval of energization start and energization stop of the piezo actuator 31 by the computer 100, control of the valve closing start timing and valve closing speed of the intake valve 21, stopping in a closed state to some extent, etc. A large degree of freedom can be controlled.

Further, in this embodiment, by energizing and stopping the energization of the piezo actuator 31 even after the intake valve 21 is closed, the hydraulic pressure in the accumulator 22 can be completely lowered and the valve closing force can be increased. Furthermore, the intake valve 21
Since the valve is gradually closed by hydraulic pressure, the noise when the valve is closed can be made very small.

In this embodiment, although the intake valve 21 is closed stepwise in FIG. 2, the piezo actuator 31 is capable of a very high-speed response, so in reality, a substantially smooth valve closing is possible. Done.

Next, another embodiment of the present invention will be described with reference to FIG.

This example is different from the first embodiment described above in that the hydraulic chamber 39,
The positions of the hydraulic port 40 and the relief port 41 are different. Even if the positions are different, the operation of the apparatus is the same as that of the first embodiment. However, the control method of the present invention is not limited to the example shown in FIG.
That is, as shown in FIG. 4, if the period of re-energization (point F ') and stop of re-energization (point G') is lengthened, the intake valve 21 can be stopped in the middle of closing the valve. (Between points M and N) By such a method, it becomes possible to control the swirl of the intake air sucked into the cylinder chamber of the engine through the intake valve 21.

Also, in FIGS. 2 and 4, the piezo actuator 31
The first energization start time of the
However, the expansion and contraction may be performed at regular intervals as shown in FIG. 5. At this time, when the energization of the piezo actuator 31 is started (point A), the pressure in the variable pressure chamber 38 is increased. Ascend (A 'point). Further, the pressure in the hydraulic chamber 39 also rises once (Point A ″) and then the pressure drops (Points C and D) when the energization ends (Point B) .However, the opening timing of the needle valve 34, FIG. It is point E as in FIG.

The opening timing of the intake valve 22 can be easily changed by changing the discharge start timing of the hydraulic pump 1.

Although the hydraulic control valve 3 of the present invention is used to control the intake valve 21 in this embodiment, the accumulator chamber 22 is used.
Can be used as a fuel injection valve or a hydraulic control valve of another hydraulic device if it is built in the hydraulic control valve 3.

In addition, the closing timing, closing amount, and closing speed of the intake valve 21 are calculated by a computer by detecting the engine speed, accelerator opening, etc., and the piezo actuator 31 is energized and de-energized, and the interval between these repetitions is calculated. By controlling such things as E / G pumping loss reduction and swirl control, fuel consumption emission can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the device of the present invention, FIG. 2 is a time chart showing the behavior of each part of the device shown in FIG. 1, and FIG. 3 is a sectional view showing another example of the device of the present invention. FIG. 4 is a time chart showing another behavior of each part of the device of the present invention, and FIG. 5 is a time chart showing still another example. 1 …… hydraulic pump, 2 …… intake valve driving part which is a driven part, 3 …… hydraulic control valve, 31 …… piezo actuator, 34 …… needle valve, 35 …… first check valve, 36 …… 2nd check valve, 38 …… transformer room, 39 ……
Hydraulic chamber.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukihiro Natsuyama 14 Iwatani, Shimohakaku-cho, Nishio-shi, Aichi Japan Auto Parts Research Institute, Inc. (56) Reference JP-A-61-52473 (JP, A) JP Sho 60-128911 (JP, A) JP 63-62977 (JP, A) JP 61-180075 (JP, A) Actual opening 61-140105 (JP, U) Actual opening 61-37410 (JP , U)

Claims (3)

[Claims] 1. A passage for forming a variable pressure chamber and a hydraulic chamber for temporarily holding a fluid, and for sequentially guiding a fluid pumped intermittently from a hydraulic pump from an inlet port to the variable pressure chamber and the hydraulic chamber. A housing provided with a passage for guiding a fluid in the hydraulic chamber to an accumulator chamber for controlling a lift amount of an intake valve through an outlet port, and a relief port for relief of the fluid in the hydraulic chamber; A piezo actuator that expands and contracts the volume of the transformation chamber by expanding and contracting in accordance with the applied voltage, and a control unit that controls the voltage applied to the piezo actuator.
Between the inlet port and the variable pressure chamber, a needle valve that is reciprocally provided in the housing, receives the pressure of the variable pressure chamber and the hydraulic pressure chamber, and connects or disconnects the hydraulic pressure chamber and the relief port. A first check valve that is provided to allow the movement of the fluid from the inlet port to the variable pressure chamber and prevent the movement of the fluid from the variable pressure chamber to the inlet port side; and a passage that connects the variable pressure chamber and the hydraulic chamber. A second check valve provided in the middle of the variable pressure chamber to allow the movement of the fluid from the variable pressure chamber to the hydraulic pressure chamber and to prevent the movement of the fluid from the hydraulic pressure chamber to the variable pressure chamber. When the needle valve shuts off the hydraulic chamber and the relief port when the fluid pressure is relatively higher than the fluid pressure in the hydraulic chamber, and when the fluid pressure in the variable pressure chamber is relatively lower than the fluid pressure in the hydraulic chamber. And a relief valve that communicates the hydraulic chamber with the relief port to relieve the oil in the hydraulic chamber, and the control means causes the piezo actuator to be energized and de-energized at predetermined intervals so that the hydraulic chamber is reduced to a predetermined pressure. Hydraulic drive control device for intake valve that controls settings. 2. The hydraulic drive control device for an intake valve according to claim 1, wherein the piezo actuator repeatedly expands and contracts for a predetermined period after the intake valve is closed. 3. The hydraulic drive control device for an intake valve according to claim 1, wherein the control means detects the engine speed or the accelerator angle to control the energization of the piezo actuator.