JP2527268Y2 - Valve train for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a valve train for an internal combustion engine in which an intake and exhaust valve is opened and closed by an actuator.

[Conventional technology]

FIG. 3 shows an example of a conventional pressure accumulating valve train. In the configuration, 01 is a hydraulic control valve body and has five holes. 02 is a control valve, which is driven by a cam 03 and a roller 04 in synchronization with the crankshaft of the engine. The intake / exhaust valve 07 opens and closes inside the actuator 06 attached to the cylinder cover 05. The actuator 06 has an upper hydraulic chamber 06a and a lower hydraulic chamber 06b, and is connected to a control valve 01 by pipings 08 and 09, respectively. 010 is an oil pressure supply device composed of a filter and a pump, and 010a is an oil tank. Reference numeral 011 denotes an accumulator, which is maintained at a required constant oil pressure and is connected to the control valve 01 via a pipeline.

Next, the operation will be described. FIG. 3 shows that the roller 04 is a cam.
Hydraulic oil from the pressure accumulator 011 passes through the pipe 09 from the control valve 01 and acts on the lower hydraulic chamber 06b of the actuator when the intake / exhaust valve is on the base circle of 03 and the intake / exhaust valve is closed. Pushing valve 07 up. At this time, the upper hydraulic chamber 06
The oil of a passes through piping 08, control valve 01, and the tank of hydraulic source 010
I am led back to 010a.

When the cam 03 rotates and the roller 04 lifts, the oil in the lower hydraulic chamber 06b of the actuator 06 is discharged to the tank 010a via the pipe 09 and the control valve 01, and at the same time, the high-pressure hydraulic oil of the accumulator 011 is controlled by the control valve. 01, piping 08, actuator 06
To the upper hydraulic chamber 06a to push down the intake / exhaust valve 07 to open it. When the cam 03 further rotates and the lift of the cam decreases to reach the base circle, the oil in the upper hydraulic chamber 06a escapes to the tank 010a, and the operating oil of the pressure accumulator 011 acts on the lower hydraulic chamber 06b, and the intake and exhaust valves 07 Will be raised and closed.

[Problems to be solved by the invention]

 The above-mentioned prior art has the following problems.

The control valve 01 has 5 holes and the structure is complicated,
The amount of oil required to open and close the intake / exhaust valve must also flow through the control valve, and the hydraulic device becomes large.

Further, it has two pipes 08 and 09 for opening and closing the valve with high-pressure oil, has a complicated actuator structure, consumes a large amount of high-pressure oil, and requires much power.

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

[Means for solving the problem]

(1) High-pressure hydraulic oil is used only for opening and closing the intake and exhaust valves.
The valve is closed by the spring force stored in the spring with the lift of the intake / exhaust valve.

Two control valves and two logic valves are provided.
If two solenoid valves are used, the two valves are used to prevent instability due to overheating of the solenoid valve coil. Ensuring operation and durability. The control valve is electrically driven and only controls the action of hydraulic pressure from the pressure accumulator to the large-diameter portion of the logic valve. The oil required to open the exhaust valve requires one logic valve and one valve from the pressure accumulator. The high-pressure pipe acts on the piston of the cylinder in the valve actuator.

Also, the small diameter sides of the two logic valves are in communication,
When the valve is closed, the other logic valve is opened to release the hydraulic pressure in the cylinder and the high-pressure pipe.

(2) In addition to the above means, a check valve that opens on the side of the open-side logic valve is further disposed between the accumulator and the open-side logic valve.

[Action]

(1) The high-pressure hydraulic oil stored in the pressure accumulator opens the open-side logic valve by the open-side control valve that is electrically driven at an arbitrary timing, and acts on the piston of the cylinder in the valve-operating actuator, thereby causing the intake and exhaust valves to operate. After the pressure is depressed, the closed control valve returns and the open logic valve closes. The intake and exhaust valves continue to be opened by hydraulic pressure, but the compression 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 held at an appropriate lift in balance with the hydraulic pressure. When the intake and exhaust required for the engine are performed, the close-side control valve opens the close-side logic valve and releases the hydraulic pressure, so that the intake and exhaust valves are closed by the air spring.

 This cycle is repeated.

(2) When the hydraulic pressure fluctuates in the high-pressure pipe from the pressure accumulator to the valve operating actuator, and the high-pressure pressure wave returns,
The check valve closes and the high pressure oil working system does not communicate with the accumulator. For this reason, this part operates as a closed end and is rigid. Therefore, even if the intake / exhaust valve tries to return and returns the oil, the pressure becomes high and the intake / exhaust valve does not largely move.

〔Example〕

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

1 is a cylinder cover, 2 is an intake and exhaust valve, 3 is an air reservoir,
4 is a check valve. Reference numeral 5 denotes an air piston, which slides in the air cylinder 6 simultaneously with the intake / exhaust valve 2. 7 is a valve actuator main body, 8 is a hydraulic cylinder, 9 is a working 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 the open side logic valve
Reference numeral 11 denotes a connection chamber 11a connected to the accumulator 16 and the upper hydraulic chamber 8a of the working piston 9, and a pressure oil chamber 11b to which the pressure oil of the accumulator 16 is supplied and discharged.
And the connection chamber 11a and the pressure oil chamber 11b
When the pressure oil is supplied to 11b, it is provided with a valve body 11c which shuts off the communication between the pressure accumulator 16 and the pressure oil chamber 8a in the connection chamber 11a. 12 is
The open side logic valve oil passage is connected to the pressure accumulator 16. 13
Is an open spool control valve, which is driven by a controller (not shown) in synchronization with the crank rotation of the engine. Reference numeral 14 denotes a closing-side logic valve. The closing-side logic valve 14 includes a connection chamber 14a connected to the oil tank 19 and a pressure oil chamber 14b through which pressure oil of the accumulator 16 is supplied and discharged.
And a valve element 14c for distinguishing between the connection chamber 14a and the pressure oil chamber 14b. 15 is a closed spool control valve and 13 is an open spool control valve.
Driven by a controller not shown in the same way as
It is a three-port control valve. Reference numeral 16 denotes a pressure accumulator, and reference numeral 17 denotes a hydraulic pressure source device for supplying high-pressure oil, and is composed of a pump and a filter. 18 is a low-pressure hydraulic power source device,
Thus, it is in communication with the valve operating actuator 7. 19 is an oil tank, 20 is a communication oil path connecting the open side logic valve and the close side logic valve, 21 is an oil path connecting the large diameter side of the open side logic valve to the open side spool control valve, and 22 is an open side spool control. An oil passage connecting the valve 13 and the pressure accumulator 16, an oil passage 23 connecting the large-diameter side of the close-side logic valve 14 and the close-side spool control valve 15, a reference numeral 24 indicating a close-side spool control valve 15 and the accumulator 16 It is an oil channel that connects

25 is an oil drain pipe from the closing logic valve 14 to the oil tank 19, 26
Is an oil drain pipe from the spool control valves 13 and 15. A check valve 101 is provided between the accumulator 16 and the open-side logic valve 11 and opens toward the open-side logic valve.

The spool control valves 13 and 15 are three-port control valves.
It has a port, a C port and a T port and is electromagnetically driven.

 Next, the operation of the present apparatus will be described.

FIG. 1 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 / exhaust valve 2 is closed.

At this time, the open and closed spool control valves 13, 15
Causes the hydraulic pressure from the accumulator 16 to act on the large-diameter sides of the open and closed logic valves 11, 14, and the logic valves 11, 14 are closed.

When the intake / exhaust valve 2 is opened, the open spool control valve 13 is driven at an appropriate time determined by a computer based on a trigger signal generated in synchronization with an engine (not shown) and the operating state of the engine. When the control valve 13 is operated, the oil passage 22 is closed, and the oil passage 21 communicates with the oil drain pipe 26 to release the hydraulic pressure on the large diameter side of the logic valve. The check valve 101 is raised from 12a and acts on the upper hydraulic chamber 8a of the hydraulic cylinder 8 in the valve actuator from the oil passage 12b and the high pressure pipe 10. The hydraulic pressure pushes down the hydraulic piston 9 to open the intake / exhaust valve 2.

At this time, the air in the air cylinder 6 is compressed and acts as an upward force, but the intake / exhaust valve lifts up to the balance point with the hydraulic pressure.

Thereafter, the open-side control valve 13 is returned, and the hydraulic pressure of the accumulator 16 acts on the large-diameter portion of the logic valve 11, so that the logic valve 11 closes.

After the logic valve 11 is closed, even if the logic valve 11 is opened due to a change in hydraulic pressure in the high-pressure pipe 10, the check valve 101 is closed. The system is closed up to the valve 101, the pressure fluctuation is not so large, and the fluctuation of the lift of the intake / exhaust valve 2 is small.

Next, FIG. 2 shows characteristics of intake and exhaust valve lifts and hydraulic pressures of the apparatus described in the embodiment.

In the figure, A is an intake / exhaust valve lift, and B is an upper hydraulic chamber.
8a is the pressure in the high pressure pipe 10 at the inlet, and C is the pressure in the communication oil passage 20 of the logic valve.

As can be seen from the figure, when the intake / exhaust valve 2 tries to return, the hydraulic pressure rises and the displacement is suppressed. Therefore, the fluctuation of the intake / exhaust valve lift during valve opening is reduced.

Next, when the intake and exhaust required for the engine are completed, 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 hydraulic pressure on the large-diameter side of the logic valve 14 is The logic valve 14 opens, and the hydraulic pressure acting on the upper hydraulic chamber 8a is released from the high-pressure pipe 10 and the communication oil passage 20 to the oil discharge pipe.
25, the hydraulic force is lost. Then, the intake / exhaust valve 2 is closed by the air compression force acting on the air piston. At this time, the lower hydraulic chamber 8b is supplied with oil from the low-pressure hydraulic power source 18, and the working piston 9 returns to the raised position in a stable state without a cavity.

[Effect of the invention]

The present invention has a hydraulic pressure source and a pressure accumulator that pressurizes and stores hydraulic oil, and in a valve operating device for an internal combustion engine that controls the hydraulic oil of the pressure accumulator to drive an intake / exhaust valve. It comprises two mutually connected logic valves for opening and closing a high-pressure oil passage connected to the upper part, and two electromagnetically driven spool control valves for controlling opening and closing of the two logic valves, and opens and closes the logic valves. A control oil pressure and hydraulic oil for driving the intake and exhaust valves to open are supplied from a high-pressure accumulator, and the intake and exhaust valves are closed by the spring force stored with the lift of the opening of the intake and exhaust valve driving piston. The configuration and the configuration in which the check valve that opens on the side of the open-side logic valve is provided between the accumulator and the open-side logic valve have the following effects.

(1) Stable operation and durability are ensured by providing two logic valves and a control valve on the electromagnetically driven spool that controls the logic valves so that the solenoid valves act at the moment of opening and the moment of closing, respectively. Is done.

(2) Since the engine can obtain the optimal opening / closing valve characteristics of the intake / exhaust valve, the engine becomes a high-performance engine with low fuel consumption.

(3) Since the consumption of high-pressure oil for driving the valve is small, the hydraulic source can be designed to be small and inexpensive. Also, the power consumption is small, and the fuel consumption is further reduced.

(4) Since the amount of oil in the control valve section can be reduced, a compact control valve can be realized, and a device having good reliability and durability can be realized.

(5) The check valve eliminates fluctuations of the intake / exhaust valve after the lift, so that stable intake / exhaust performance can be obtained.

As a result, the performance of the engine is also stabilized, and a good operating state can be maintained.

[Brief description of the drawings]

FIG. 1 is a system diagram of a valve gear according to an embodiment of the present invention.
FIG. 3 is a characteristic diagram of the valve lift and the hydraulic pressure in the above, and FIG. 3 is a system diagram of a conventional pressure accumulating valve device. 2 ... intake and exhaust valves, 5 ... air piston, 6 ... air cylinder,
9 ... working piston, 11 ... open side logic valve, 13 ... open side spool control valve, 14 ... closed side logic valve, 15 ... closed side spool control valve, 16 ... accumulator, 17 ... hydraulic power source, 101 ... check valve .

Continued on the front page (72) Etsuo Kunimoto 1-1, Akunoura-cho, Nagasaki-shi, Nagasaki Prefecture Mitsubishi Heavy Industries, Ltd. Nagasaki Research Laboratory (72) Inventor Yasutaka Irie 12 Nishikicho, Naka-ku, Yokohama-shi, Kanagawa Prefecture Mitsubishi Heavy Industries, Ltd. (56) References JP-A-2-248607 (JP, A)

Claims (1)

(57) [Scope of request for utility model registration] 1. An intake / exhaust valve 2 slidably supported in a vertical direction, and a pressure accumulator 16 slidably supported in a vertical direction and abutting on an upper end of the intake / exhaust valve 2 and in an upper hydraulic chamber 8a. A working piston 9 which pushes down and opens the intake / exhaust valve 2 by supplying the pressure oil, and an intake / exhaust system which is attached to the intake / exhaust valve 2 and is urged upward by a high-pressure fluid supplied from the outside. An air piston 5 for closing the valve 2 and an accumulator
16 and a connection chamber 11a connected to the upper hydraulic chamber 8a of the working piston 9; a pressure oil chamber 11b for supplying and discharging the pressure oil of the accumulator 16;
11a and the pressure oil chamber 11b are separated from each other, and the communication between the pressure accumulator 16 and the pressure oil chamber 8a is established when the pressure oil is supplied to the pressure oil chamber 11b.
An open-side logic valve 11 comprising a valve body 11c that shuts off within 11a,
Connect to accumulator 16 and oil tank 19 at desired timing
An electromagnetically driven open-side spool control valve 13 that shuts off and supplies pressure oil to and from the pressure oil chamber 11b, and a connection chamber 14a that connects to an oil tank 19,
A closed-side logic valve 14 comprising a pressure oil chamber 14b to which the pressure oil of the accumulator 16 is supplied / discharged, and a valve body 14c for separating the connection chamber 14a from the pressure oil chamber 14b.
At the desired timing, an electromagnetically driven closed spool control valve 15 that is connected and disconnected from the pressure accumulator 16 and the oil tank 19 and supplies and discharges pressure oil to and from the pressure oil chamber 14b, and pressure oil is supplied to the pressure oil chamber 11b When pressure oil is supplied to the portion of the connection chamber 11a where the communication with the pressure accumulator 16 is interrupted by the valve body 11c and the pressure oil chamber 14b
A check valve that opens to the open-side logic valve side between the communication oil passage 20 that communicates with a portion of the connection chamber 14a where communication with the oil tank 19 is interrupted by c, and the pressure accumulator 16 and the open-side logic valve 11 A valve train for an internal combustion engine, comprising: a valve 101.