JPH05195739A - Controller for gas exchange valve for internal combustion engine - Google Patents

Abstract

PURPOSE: To quickly actuate a storage piston without necessity of an additive big regulating force or an individually usable pressure medium source. CONSTITUTION: In order to correctly control a gas exchange valve of an internal combustion engine that is driven through an exchangeable liquid column 20, a storage piston 31 of a pressure medium storage equipment is constituted as a valve meanwhile. When the valve is shut off, the valve is loaded without counteraction force by the pressure of the liquid column. And the valve is pressed and opened by the pressure medium of the guided liquid column 20 through controller valves 48 and 46.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a gas exchange valve of an internal combustion engine, which includes a cam shaft which can be driven synchronously with the rotational speed of the internal combustion engine. Cams allow each liquid column to reciprocate on one side of an adjacent drive piston, one each connected to each gas exchange valve and loaded by a return spring.
Equipped with two adjusting pistons, which limit the liquid column on the other side and have a connecting passage,
This connecting passage connects each liquid column to each storage device, which storage device comprises a storage piston adjustable against the force of a spring, which storage piston is at the same time a closing member of the valve. Of the pressure chamber provided around the peripheral wall of the storage piston on the end face side and the storage piston together with the sealing edge portion. And a pressure chamber connected to the connection passage and having a pressure medium passage opening to the storage chamber via a check valve.

[0002]

2. Description of the Related Art A known control device of the type mentioned at the outset (German Patent Application No. 3929072).
In the storage device, the piston of the storage device is a part of the magnet valve, and the magnet valve simultaneously causes a backward movement accompanied by a reduction of the load of the piston as the closing member. This means a mass that is moved significantly, which mass must be moved by an electromagnet, which adversely affects the switching speed of the valve and increases with increasing engine speed or switching frequency. Causes a control error. Therefore, the control of the valve movement in this manner is performed with the required accuracy only in a specific rotational speed range. Furthermore, a throttle hole is provided in the valve member or piston of the reservoir to improve the switching speed,
A constant pressure medium flow passes through the throttle hole without pressure when the piston is closed. This requires a separate pressure medium discharge pump, which has to continuously supply high pressure medium. This is relatively expensive and the pressure medium source already present in the internal combustion engine cannot be used together with the internal combustion engine oil lubrication circuit.

[0003]

DETAILED DESCRIPTION OF THE INVENTION A common control valve which branches off a pressure passage from a connection passage for connecting a liquid column to a storage device and which can be electrically controlled via a check valve which opens in the branching direction. The outlet of the control valve is connected to a front control valve electrically controllable by the control device before the opening control of the control valve, the outlet of the front control valve being at least one of the storage devices. Connected to one pressure medium passage.

[0004]

With the above arrangement of the present invention, the oil pressure in the liquid column is utilized as a servo control pressure to provide a rapid switching of the piston of the storage device. Only electrically controllable low mass valves are required to control the storage device. Only the switching time of the electrically controllable control valve is relevant to the control accuracy of the control device. Whereas only this valve is exposed to high pressure, the front control valve may have a relatively large inertia, since it is activated before its original control function.

[0005]

1 shows a gas exchange valve of an internal combustion engine, which is controlled by a control device according to the invention. Another gas exchange valve is similarly constructed. The gas exchange valve is a conventional inlet valve 1 or outlet valve, which controls the gas passage 4 to the opening of the combustion chamber 5 with a valve disc 3 in the cylinder head 2 of the internal combustion engine. The shaft 6 of the gas exchange valve is guided in the cylinder head and projects into the cylindrical chamber 8 in which the adjusting piston 9 is received, the adjusting piston being rigidly connected to the end of the shaft, End wall 10 on the combustion chamber side
And the stopper 11 can be moved. In this case, the adjusting piston is loaded by the return spring 12 in the direction of the stopper 11. The end face 14 of the adjusting piston opposite to the return spring bears a compression spring 15, which at its other end is in contact with the drive piston 17.
The drive piston is movable in a hole 18 adjacent to the stopper 11 and closes the liquid column 20 between the drive piston itself and the end face 14 of the adjusting piston 9. With the end face 21 of the drive piston opposite to the compression spring 15, the drive piston is in contact with the cam 22 of the camshaft 23, which is correspondingly synchronized with the rotation of the crankshaft of the internal combustion engine. Driven at a reduced speed, the cam 22 causes a reciprocating movement of the drive piston.

A pressure medium supply passage 25 opening in the hole 18
Has a check valve 26 which opens in the direction of the hole 18. A connection passage 28 branches from the hole 18 to form the storage device 2
It leads to 9. The storage device includes a storage cylinder chamber 30 and a storage piston 31 movably arranged in the storage cylinder chamber.
This storage piston is loaded by a compression spring 34 on the rear side which is released via a relief passage 33. The storage piston 31 is configured as a valve closing member for the valve 36 and has an end face 37 opposite the compression spring 34.
Is formed as a sealing edge 38, which contacts the valve seat 39 under the action of the compression spring 34. In this case, the valve seat is designed as a conical transition from the diameter of the storage cylinder chamber 30 to the storage chamber 40 formed between the end surface 37 of the storage piston 31 and the cylinder head. In the closed position where the storage piston 31 and the valve seat 39 are in contact, the storage piston separates the storage chamber 40 from the pressure chamber 41, which is adjacent to the valve seat 39 and the wall of the storage cylinder chamber and the storage piston 31. It is configured as a ring groove formed by the peripheral wall. A connection passage 28 opens in the pressure chamber.

A pressure passage 43 branches from the connection passage 28, has a check valve 44 that opens in the branch direction, and communicates with an electrically controlled control valve 46. This control valve has the same inlet, pressure passages 43 ', 43 from another gas exchange valve.
〃, 43 ″ ′ is also open. The electrically controlled control valve 46 is a two-port two-position valve, and the outlets of the two-port two-position valve are two front control valves 47 that can be electrically controlled. , 4
8 and these pre-control valves are likewise configured as 2-port 2-position valves, the outlets of which are via the pressure medium passage 50 and the check valve 51 respectively a gas exchange valve. Is connected to the storage room 40. Only one pressure medium passage 50 is shown in the drawing, the other pressure medium passage is not shown. Each front control valve is intended to control two storage devices in parallel, such that the storage devices controlled by one front control valve do not operate directly in sequence after operation of the gas exchange valve. In a four-cylinder engine having four cylinders and having a gas exchange valve operating sequence of cylinders 1-3-4-2, for example, the front control valve 48 controls the storage device of the gas exchange valves of cylinders 1 and 4, Front control valve 47
Controls the storage of the gas exchange valves of cylinders 2 and 3.

A cam 22 in an operating internal combustion engine
Drives the drive piston 17 in the opening direction of the gas exchange valve 1, for example. When the storage device 29 is in the closed position together with the check valve 26 and the control valve 46 is closed, the constant liquid column 2 between the drive piston 17 and the adjusting piston 9 is reached.
0 is formed, this liquid column simultaneously moving the adjusting piston 9 upon movement of the drive piston, which in turn brings the gas exchange valve to the open position. In this case, the gas exchange valve is cam 2.
It reciprocates between an open position and a closed position in synchronization with the movement of 2. When it is desired to change the control time of the gas exchange valve, the liquid column is changed by operating the storage device 29. In order to shorten the opening stroke, the valve 36 is opened at a predetermined time, the driving pressure of the adjusting piston is reduced, and the adjusting piston is returned to the end position defined by the stopper 11. This ends the opening phase early. The volume of pressure medium subsequently displaced by the drive piston is received by the storage piston 31. Upon return of the drive piston, the amount of pressure medium received is returned to the liquid column 20. The leak amount that has flown out in some cases is replenished at this stage via the pressure medium supply passage 25 and the check valve 26.

The control of the valve 36 of the storage device 29 is effected as follows: When the liquid column 20 is under pressure at the beginning of the movement of the drive piston 17, this pressure is also acting in front of the control valve 46. The control device 53 brings one of the front control valves 47 or 48 into the open position, which results, for example, in a connection between the control valve 46 and the storage devices of the first and fourth cylinders. However, of these cylinders, only cylinder 1 should be operated according to the control plan of the internal combustion engine. The hydraulic pressure of the liquid column also acts on this cylinder via the connection passage 28. The storage piston 31 of the gas exchange valve of the cylinder 4 corresponds to the corresponding drive piston 17
Pressure is not applied due to lack of operation. In order to introduce the opening process of the valve 36, the control valve (quick switching valve) is controlled to be opened by the control device 53, and the pressure shock reaches the storage chamber 40 via the pressure medium passage 50. This pressure shock tends to move the storage piston 31 away from its valve seat 39 quickly, so that the pressure of the liquid column is exerted effectively on the entire end face 37 of the storage piston 31, which causes the storage piston 31 to return.
4, the load of the liquid column is reduced by the discharge of the pressure medium, and the adjusting piston 9 is returned to the starting position in contact with the stopper 11 in spite of the movement of the drive piston 17. The pressure shock, which also acts on the parallel-connected storage chambers for the cylinder 4, does not give rise to a control process there.
This is because the liquid column there is not under pressure and the gas exchange valve is originally in the closed position.

With such a configuration, the gas exchange valve can be controlled remarkably accurately even when the rotational speed is high with a small supply amount of the pressure medium.

[Brief description of drawings]

1 is a circuit diagram of an embodiment according to the invention of a control device for a gas exchange valve of an internal combustion engine.

[Explanation of symbols]

1 gas exchange valve, 2 cylinder head, 3 valve plate,
4 gas passages, 5 combustion chambers, 6 shafts, 8
Cylindrical chamber, 9 adjusting piston, 10 end wall, 11
Stopper, 12 Return spring, 14 End face, 15
Compression spring, 17 drive piston, 18 hole, 20
Liquid column, 21 end face, 22 cam, 23 cam shaft,
25 pressure medium supply passage, 26 check valve, 28
Connection passage, 29 storage device, 30 storage cylindrical chamber,
31 storage piston, 33 escape passage, 34 compression spring, 36 valve, 37 end face, 38 sealing edge, 39 valve seat, 40 storage chamber, 41 pressure chamber,
43 pressure passage, 44 check valve, 46 control valve,
47,48 front control valve, 50 pressure medium passage, 53
Control device

Claims (2)

[Claims] 1. A control device for a gas exchange valve of an internal combustion engine, comprising a cam shaft (23) which can be driven synchronously with the rotational speed of the internal combustion engine, and a cam (2) of the cam shaft.
2) allows each liquid column (20) to reciprocate on one side of an adjacent drive piston (17), is connected to each gas exchange valve (1) and is loaded by a return spring (12). Respectively one regulating piston (9), which limits the liquid column on the other side and which has a connecting passage (28),
This connecting passage connects each liquid column (20) to each storage device (29), which storage device is a spring (34).
Comprises a storage piston (31) adjustable against the force of the valve, which storage piston is at the same time a closing member of the valve (36) and a sealing edge (38) of the end face (37). It is adapted to be brought into contact with a seat (39), which together with the sealing edge forms a storage chamber (40) on the end face side and a pressure chamber (41) provided around the peripheral wall of the storage piston. It is designed to be partitioned, and the pressure chamber has a connection passage (28).
Connected to the storage chamber (4) via a check valve (51).
0) in the type having a pressure medium passageway (50) open to the pressure passageway (4) from each connection passageway (28).
3) is branched, and this pressure passage communicates with a common controllable valve (46) that is electrically controllable via a check valve (44) that opens in the branching direction, and the outlet of this control valve Is connected to a front control valve (47, 48) which is electrically controllable by a control device (53) before the opening control of the control valve (46), the outlet of which is at least the storage device. Control device for a gas exchange valve of an internal combustion engine, characterized in that it is connected to one pressure medium passage (50). 2. Two front control valves (47, 48) are provided, the front control valves are alternately and sequentially controlled to be opened, and the outlets of the front control valves are associated gas exchange valves. 2. The control device according to claim 1, wherein the control device is assigned to actuate alternately the gas exchange valve cooperating with the storage device associated with another front control valve.