JPH04128508A - Valve system device of internal combustion engine - Google Patents

Abstract

PURPOSE:To obtain optimal opening/closing valve characteristics of an intake/exhaust valve by providing two mutually communicated logic valves for opening/closing a high pressure oil passage communicated with the upper part of a piston for driving the intake/exhaust valve, and providing two electromagnetically driven spool control valves for controlling opening/closing of both logic valves. CONSTITUTION:When an intake/exhaust valve 2 comes in a valve opening period, a opening side spool control valve 13 is driven to close an oil passage 22, and an oil passage 21 is communicated with an exhaust oil pipe 26 to open a logic valve 11. Hence, oil pressure in a pressure accumulator 16 acts from an oil passage 12 and a high pressure pipe 10 to the upper part oil pressure chamber 8a of an oil pressure cylinder 8 in a valve system actuator 7 so as to push down a hydraulic piston 9 to open the intake/exhaust valve 2. When intake/exhaust which is necessary for an engine is carried out, a closing side spool control valve 15 is driven to close an oil passage 24, and an oil passage 23 is communicated with the exhaust oil pipe 26 to open a logic valve 14. And, the intake/exhaust valve 2 is closed by compression force of air acting on an air piston 5. At this time, oil is supplied from a low oil pressure source 18 in a lower part oil pressure chamber 8b so as to return the operating piston 9 to a raised position in its stabilized condition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a valve operating system for an internal combustion engine in which intake and exhaust valves are opened and closed by actuators.

[Conventional technology] An example of a conventional pressure accumulation type valve operating device is shown in FIG.

Its structure is as follows: 01 is a hydraulic control valve main body having 5 holes, 02 is a control valve, which is driven by a cam 03 and a roller 04 in synchronization with the engine crankshaft. An intake and exhaust valve 07 opens and closes inside an actuator 06 attached to a cylinder cover 05. The actuator 06 has an upper hydraulic chamber 06a and a lower hydraulic chamber 06b, each of which is connected to the control valve 01 through a pipe 08.09. 0
10 is a hydraulic pressure supply device composed of a filter and a pump, and 010a is an oil tank.

011 is the pressure accumulator, which maintains the required constant oil pressure and controls the control valve 01.
It is connected by a conduit.

Next, we will discuss the effect. In this figure, roller 04 is cam 0.
3, and when the intake and exhaust valves are closed, the hydraulic fluid from the pressure accumulator 011 flows from the control valve 01 to the pipe 0.
9 and acts on the lower hydraulic chamber 06b of the actuator, pushing up the intake/exhaust valve 07. At this time, the oil in the upper hydraulic chamber 06a is guided back to the tank O]Oa of the hydraulic power source 010 via the pipe 08 and the control valve 01.

When the cam 03 rotates and the roller 04 lifts, the oil in the lower hydraulic chamber 06b of the actuator 06 is discharged from the tank 010a↓2 through the pipe O9 and the control valve 01, and at the same time, the high-pressure hydraulic oil in the pressure accumulator 011 is Control valve 01, piping 08
The air is guided to the upper hydraulic chamber 06a of the actuator 06, and the intake and exhaust valves 07 are pushed down and opened. When the cam 03 further rotates and the lift of the cam decreases until it reaches the base circle, the oil in the upper hydraulic chamber 06a escapes to the tank 010a, and the pressure accumulator 0
No. 11 hydraulic oil acts on the lower hydraulic chamber 06b, and the intake/exhaust valve 07 is raised upward and closed.

(Problem to be solved by the invention) The above-mentioned prior art has the following eight points.

The control valve 01 has 5 holes and has a complicated structure.
The amount of oil required to open and close the intake and exhaust valves also needs to flow through the control valve, resulting in a large hydraulic system.

Furthermore, the actuator has two pipes 0809 for opening and closing the valve using high pressure oil, and the structure of the actuator is complicated, consuming a large amount of high pressure oil and requiring a large amount of power.

Furthermore, the control valve 01 is driven by the cam 03, and the opening/closing timing of the intake and exhaust valves cannot be changed freely.

Means for Solving Problem C8] High-pressure hydraulic oil is used only to open the intake and exhaust valves, and the valves are closed using the spring force stored in the springs as the intake and exhaust valves lift.

In addition, two control valves and two logic valves are provided, and the control valve is electrically driven and only controls the action of hydraulic pressure from the pressure accumulator to the large diameter part of the logic valve, and controls the opening of the exhaust valve. The required oil is applied from the pressure accumulator to the piston of the cylinder in the valve actuator via one logic valve and one high-pressure pipe.

Further, the small diameter sides of the two logic valves are in communication with each other, and when the valve is closed, the other logic valve is opened to release the hydraulic pressure in the cylinder and the high pressure pipe.

[Effect]

The high-pressure hydraulic oil stored in the pressure accumulator is electrically driven at any given time by the open-side control valve, which causes the open-side logic valve to open and act on the piston in the cylinder in the valve actuator, opening the intake and exhaust valves. After pushing down, the closing side control valve returns and the opening side logic valve closes 4. The intake and exhaust valves continue to open due to hydraulic pressure, but the compressive force of the air by the air piston that moves together with the exhaust valve acts as a force in the valve closing direction, and is maintained at an appropriate lift in balance with the hydraulic pressure. I! When the necessary intake and exhaust operations are completed, the closing side control valve opens the closing side logic valve and the hydraulic pressure is released, so that the air spring closes the intake and exhaust valves.

This cycle is repeated.

[First example] A first embodiment of the invention will be described with reference to FIG.

] is the cylinder cover, 2 is the intake and exhaust valve, 3 is the air reservoir, 4
65 is a check valve, and 65 is an air piston that slides in the air cylinder 6 at the same time as the intake and exhaust valve 2. 7 is the valve actuator body, 8 is the hydraulic cylinder, 9 is the operating piston,
8a is an upper hydraulic chamber, and 8b is a lower hydraulic chamber.

10 is a high pressure pipe, 11 is an open side logic valve, and 12 is an open side logic valve oil passage, which is connected to a pressure accumulator 16. 13 is an open side spool control valve, which is controlled by a controller (not shown).
141 is a closing side logic valve which is driven in synchronization with the crank rotation of the engine; 15 is a closing side spool control valve; like the opening side spool control valve 13, it is driven by a controller not shown; control valve. Reference numeral 16 denotes a pressure accumulator, and I7 denotes a hydraulic pressure device, which supplies high-pressure oil, and is composed of a pump and a filter. Reference numeral 18 denotes a low-pressure hydraulic power source device, which is communicated with the valve actuator tough through a conduit 18a. 19 is an oil tank, 20 is a communication oil passage 1 connecting the open side logic valve and the closing side logic valve, 21 is an oil passage connecting the large diameter side of the opening side logic valve and the closing side spool control valve, 22 is an open side logic valve. 23 is an oil passage connecting the side spool control valve 13 and the pressure accumulator 16, 23 is an oil passage connecting the large diameter side of the closing side logic valve 14 and the closing side spool control valve 15, and 24 is an oil passage connecting the closing side spool control valve 15 and the pressure accumulator. It is an oil path that connects with the container 16.

25 is an oil drain pipe from the closing side logic valve 14 to the oil tank 19, and 26 is an oil drain pipe from the spool control valves 13 and 1.5.

The spool control valves 13 and 15 are 30 control valves, each having a P boat, a C boat, and a T port, and are electromagnetically driven.

Next, the operation of the O device will be explained.

This figure shows a state in which the air pressure in the air reservoir 3 acts on the lower part of the air piston 5 and the intake and exhaust valves 2 are closed.

At this time, the open and close side spool control valves 13 and 15 open the hydraulic pressure from the pressure accumulator, and the close side logic valve 1].

14 on the large diameter side of the logic valve 11. ]4 is closed.

The opening side spool control valve 13 is actuated at the opening timing of the intake/exhaust valve 2 (in this case, the opening side spool control valve 13 is activated by a trigger signal issued in synchronization with the engine (not shown) and at an appropriate timing determined by the computer based on the engine operating condition Bc). When the pipe control valve 13 is operated, the oil 1!122 is closed and the oil passage 21 is closed.
passes through the oil drain pipe 26 and the hydraulic pressure on the large diameter side of the logic valve is released, so the logic valve 11 opens, and the hydraulic pressure in the pressure accumulator 16 is transferred from the oil passage 12 and the high pressure pipe IO to the upper part of the hydraulic cylinder 8 in the valve actuator 7. It acts on the hydraulic chamber 8a. This oil pressure pushes down the hydraulic piston 9 and opens the intake and exhaust valves 2.

At this time, the air in the air cylinder 6 is compressed and acts as an upward force, but the intake and exhaust valves 2 are lifted to a point where the force balances with the oil pressure.

Thereafter, the open-side control valve 13 is returned to its original position, and the hydraulic pressure of the pressure accumulator 16 acts on the large diameter portion of the logic valve 11.
1 is closed.

When the intake and exhaust necessary for the engine are performed, the closing side spool control valve 15 is driven, and the oil passage 24 is closed, and at the same time, the oil passage 23 and the oil drain pipe 26 are connected, and the large diameter side of the logic valve 14 is connected. Since the oil pressure is released, the logic valve 14 is closed, and the oil pressure that was acting on the upper hydraulic chamber 8a is released from the high pressure pipe 10 and the communication oil passage 20 to the oil drain pipe 25, and the acting force of the oil pressure disappears. Then, the air compressive force acting on the air piston 5 causes the intake and exhaust valves to close. At this time, the lower hydraulic chamber 8b is replenished with oil from the low pressure hydraulic pressure s18, and the actuating piston 9 returns to the raised position in a stable state without the formation of a cavity.

In the above embodiment, an air spring is used to return the intake and exhaust valves, but a normal coil spring may also be used.

Next, the characteristics of the valve train shown in the first embodiment will be explained with reference to FIG.

A is the intake/exhaust valve lift, B is the logic valve communication section hydraulic pressure, C is the opening side logic valve large diameter section hydraulic pressure, and D is the closing side logic valve large diameter section hydraulic pressure.

In FIG. 2, a, b, and c are high-frequency hydraulic vibrations caused by cavitation. First, to explain part a, when the open side spool control valve 13 is activated and the hydraulic pressure on the large diameter side of the logic valve is released, the hydraulic pressure of the pressure accumulator 16 acts, and the logic valve 11 opens vigorously to the maximum stroke position. It reaches and stops. At this time, a large amount of cavities are created. After that, when the control valve 13 is returned to its original position, the accumulated pressure acts on this part and the logic valve 11 is closed, but the cavity created earlier is collapsed, so high-frequency oil pressure fluctuations are observed. This causes so-called cavitation erosion, which reduces the durability of the parts.

Regarding part b, the phenomenon is exactly the same, and it occurs with respect to the closing side logic valve 14.

Moreover, when the closing side logic valve 14 suddenly opens, the pressure in the logic valve connecting portion shown in the high pressure pipes 10 and d drops sharply.
Close the intake and exhaust valves tightly as shown in e.

For this reason, the intake/exhaust valve 2 is seated on the valve seat at a high speed, and there is a risk of damage. Furthermore, since a cavity is created in the high pressure pipe 10 and the logic valve communication part 20, when the intake and exhaust valves are opened in the next cycle, the pressure will rise suddenly as shown in C, or the timing will fluctuate, causing the valves to open. Timings may vary.

[Second example] A second embodiment of the invention will be described with reference to FIG.

A restriction 10 is provided in a part of the oil drainage system of the open side spool control valve 13, and a restriction 1 is provided in a part of the oil drainage system of the closing side spool control valve #]5.
02, and a throttle 103 is provided in a part of the oil drainage system of the closing side logic valve 14, and the other configurations are the same as in the first embodiment.

Next, the operation of this device will be explained.

At the third time, the air pressure of the air ff13 acts on the lower part of the air piston 5, and the intake and exhaust valves 2 are closed.

At this time, the open side and close side spool control valves 1315 act on the hydraulic pressure from the pressure accumulator 16 on the large diameter side of the open/close side logic valve 1114, and the logic valve 11.14 is closed. When it is time to open the intake and exhaust valves 2, a trigger signal is generated in synchronization with the engine (not shown) and the operating state of the engine.
The open side spool control valve 13 is driven at an appropriate time determined by the computer. When the control valve 13 operates, the oil passage 22 is closed, the oil passage 21 passes through the oil drain pipe 26, and the hydraulic pressure on the large diameter side of the logic valve is released. However, aperture 10
Due to the effect of 1, the oil escapes slowly, and the logic...
The opening of the valve 11 is not so fast, and no cavity is created in this part.When the logic valve 】】 opens, the hydraulic pressure of the pressure accumulator 6 is transferred from the oil line 12 and the high pressure pipe IO to the valve operating valve. It acts on the hydraulic chamber 8a of the hydraulic cylinder 8 in the actuator. This oil pressure pushes down the hydraulic piston 9 and opens the intake and exhaust valves. At this time, the air in the air cylinder 6 is compressed and acts as an upward force, but the intake and exhaust valves are lifted to the point of balance with the oil pressure.

After that, the open side control valve [3] is returned, and the hydraulic pressure of the pressure accumulator [6] acts on the large diameter part of the logic valve 11, closing the logic valve 11. However, since no cavity is generated, the hydraulic pressure increases smoothly. act.

Next, the characteristics of the valve train shown in the second embodiment will be explained with reference to FIG.

A shows the valve lift, B shows the logic valve connection oil pressure, C shows the open side logic valve large diameter part pressure, and D shows the closing side logic valve large diameter part pressure.

As shown in Figure C, the pressure drop immediately after the spool control valve 1315 is activated becomes gradual, and
4 is closed, the high frequency pressure fluctuations seen in the past do not occur.

Next, when the intake and exhaust necessary for the engine are completed, the closing side spool control valve 15 is driven, the oil passage 24 is closed, and at the same time, the oil passage 23 and the oil drain pipe 25 are connected, and the hydraulic pressure on the large diameter side of the logic valve 14 is increased. comes out. At this time, due to the effect of the throttle 102, the closing logic valve 14 opens gently without creating a cavity, similar to the opening logic valve 11 described above, and the upper hydraulic chamber 8
The oil pressure that was acting on a is released from the high pressure pipe 10, the communication oil passage 20, and the oil drain pipe 25-. At this time, the effect of the throttle 103 slows down the oil flow.・Therefore, no cavities occur in the high pressure pipe section.

When the hydraulic pressure decreases, the air compression force acting on the air piston 5 causes the intake and exhaust valves 2 to close. The closing speed of this intake/exhaust valve 2 is as shown in part e of FIG.
It's not very big, and the urge when seated is also small.

As seen at D in FIG. 4, the hydraulic pressure of the closing side logic valve 14 becomes smooth, and the pressure at the early part C and the latter part d of the logic communication section shown in B acts gently.

(Effects of the Invention) (1) The present invention has a hydraulic pressure source that pressurizes and stores hydraulic oil and a pressure accumulator, and controls the hydraulic oil in the pressure accumulator to drive an internal combustion engine that drives intake and exhaust valves. In the valve device, two mutually communicating logic valves open and close high-pressure oil passages communicating with the upper part of the piston for driving the intake and exhaust valves, and two electromagnetically driven spool controls that control the opening and closing of the two logic valves. a valve, the control hydraulic pressure for opening and closing the logic valve and the hydraulic oil for driving the opening and opening of the intake and exhaust valves are supplied from a high-pressure pressure accumulator, and as the piston for driving the intake and exhaust valves is lifted to open the valves. By configuring the intake and exhaust valves to be closed by the stored spring force, the following effects are achieved.

(a) It is possible to obtain the optimal opening/closing characteristics of the intake and exhaust valves for the engine, resulting in a high-performance engine with low fuel consumption.

(b) Since the consumption of high-pressure oil for driving the valve is low, the hydraulic power source can be designed to be small and inexpensive.

In addition, the power consumption is low and the fuel consumption is further improved.

(c) Since the amount of oil in the control valve section is small, the control valve becomes compact and a device with good reliability and durability can be realized.

(2) In addition to the configuration in item (1) above, the present invention provides the above (a) by providing a restriction in the oil drain system of the closing side logic valve and the oil drain system of the two spool control valves. ~(
In addition to the effect of c), it has the following effect.

(d) There is no cavity formation in the Ron's shift valve part, and damage caused by cavitation erosion can be prevented.

(E) Since the formation of cavities in the high-pressure pipe section is eliminated, stable valve opening timing can be maintained without the occurrence of erosion, and at the same time, the valve closing speed can be controlled, so the collision between the valve and valve seat can be controlled. It can also prevent damage caused by

(f) With the above items (d) and (e), stable operation, high reliability and durability can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a two-position valve train according to the first embodiment of the present invention,
No. 2 is a characteristic diagram showing the intake/exhaust valve lift and oil pressure status in the first embodiment, FIG. 3 is a system diagram of the valve train according to the second embodiment of the present invention, and No. 4V is a characteristic diagram showing the situation of the intake/exhaust valve lift and oil pressure in the first embodiment. FIG. 5 is a characteristic diagram showing the intake/exhaust valve lift and oil pressure status in this example, and is a system diagram of a conventional pressure accumulation type valve operating system. 2... Intake and exhaust valve, 6... Air nolinda, 11... Opening side logic valve, 14... Closing side logic valve, 16... Pressure accumulator, 5... Air piston, 9... Operating piston, 13... Opening side spool control valve, 15... Closing side spool control valve, 17... Hydraulic pressure source

Claims (2)

[Claims] (1) In a valve train for an internal combustion engine that has a hydraulic pressure source that pressurizes and stores hydraulic oil and a pressure accumulator, and controls the hydraulic oil in the pressure accumulator to drive the intake and exhaust valves, a piston for driving the intake and exhaust valves is used. two logic valves that communicate with each other to open and close high-pressure oil passages that communicate with the upper part of the logic valve, and two electromagnetically driven spool control valves that control the opening and closing of the two logic valves, and the logic valve opens and closes the logic valve. Control hydraulic pressure to open the intake and exhaust valves and hydraulic oil to open the intake and exhaust valves are supplied from a high-pressure pressure accumulator, and the intake and exhaust valves are opened by the spring force stored as the intake and exhaust valve driving piston lifts to open the valves. A valve train for an internal combustion engine, characterized in that it is configured to operate a valve. (2) In a valve train for an internal combustion engine that has a hydraulic pressure source that pressurizes and stores hydraulic oil and a pressure accumulator, and controls the hydraulic oil in the pressure accumulator to drive the intake and exhaust valves, a piston for driving the intake and exhaust valves is used. Two mutually communicating open-side logic valves and closing-side logic valves that open and close high-pressure oil passages communicating with the upper part of the valve, and two electromagnetically driven spool control valves that control opening and closing of the two logic valves. Control hydraulic pressure for opening and closing the two logic valves and hydraulic oil for driving the opening of the intake and exhaust valves are supplied from a high-pressure pressure accumulator, and as the piston for driving the intake and exhaust valves is lifted to open, The intake and exhaust valves are configured to open by the stored spring force, and furthermore, throttles are provided in the oil drainage system of the closing side logic valve and the oil drainage system of the two spool control valves, respectively. Valve gear for internal combustion engines.