KR20050016981A - Device for the control of gas exchange valves - Google Patents

Abstract

The present invention relates to a gas exchange valve control apparatus for an internal combustion engine, the apparatus comprising a hydraulic valve actuator (11) each assigned to one gas exchange valve, wherein the hydraulic valve actuator acts on the gas exchange valve. A piston 13 and two hydraulic actuation chambers 121, 122 constrained by the regulating piston 13 are included. The first working chamber 121 acting in the closing direction on the gas exchange valve among the working chambers is continuously filled with pressurized fluid and the second working chamber 122 acting in the opening direction on the gas exchange valve comprises two electrical control valves. It is possible to alternately fill and empty the pressurized fluid by means of (25, 26). In order to reduce costs, one valve actuator pair 11a, 11b is provided with a single electric control valve 25, the hydraulic pressure being applied to the inlet side of the electric control valve and the outlet side of the valve actuator 11a. 2 is connected to the working chamber 122. The second working chamber 122 of the other valve actuator 11b is filled with the fluid by the switching valve 29 and also by the hydraulic pressure in the second working chamber 122 of the one valve actuator 11a.

Description

Device for the control of gas exchange valves

The present invention relates to a gas exchange valve control device in a combustion cylinder of an internal combustion engine, according to the preamble of claim 1.

In the case of known devices of this kind (DE 198 26 047 A1), the first working chamber of each valve actuator is continuously connected to a hydraulic source providing a high pressure fluid, in which case the regulation of the valve actuator The piston is mainly connected integrally to the valve tappet of the corresponding gas exchange valve, the second actuating chamber of the valve actuator is connected to the first electric control valve which, on the one hand, alternately opens and closes the supply line to the hydraulic source, on the other hand It is connected to a second electrical control valve which alternately opens and closes the relief line which is guided to the fluid reservoir. The electrical control valve is formed from a 2/2 directional magnetic valve that is spring restoring. When the gas exchange valve is closed, the regulating piston of the valve actuator is disconnected from the hydraulic source via the first electrical control valve and also via the second electrical control valve to the relief line due to the first working chamber permanently connected to the hydraulic source. It takes its basic position due to the connected second working chamber. Both electric control valves are switched to open the gas exchange valve. The second working chamber of the valve actuator is thus closed to the relief line via the second electrical control valve on the one hand and connected to the supply line to the hydraulic source via the first electrical control valve on the other hand. Since the regulating piston face that restricts the second actuation chamber in the valve actuator is larger than the regulating piston face that limits the first actuation chamber, the regulating piston moves out of its default position as the volume of the first actuation chamber becomes smaller. Open the gas exchange valve. The size of the opening stroke depends on the formation of the electrical control signal applied to the first electrical control valve, and the opening speed depends on the hydraulic pressure controlled by the hydraulic source. In order to maintain the gas exchange valve in a specific open position, the first electrical control valve is switched to close the supply line to the second working chamber of the valve actuator. In this way, the total opening positions of the gas exchange valve are adjusted by the electric control device for forming the control signal. The gas exchange valve is closed by resetting the second electric control valve to its open position, so that the first actuating chamber of the valve actuator is again connected to the relief line. In order to control the gas exchange valve, two electric control valves are required, each of which properly pressurizes or reliefs the pressure within the second actuating chamber of the corresponding valve actuator.

1 is a circuit diagram of an apparatus for controlling eight gas exchange valves disposed in four different combustion cylinders of a four cylinder internal combustion engine.

FIG. 2 is a partial circuit diagram of a modified device for controlling the gas exchange valve of FIG. 1. FIG.

3 is a schematic illustration of a gas exchange valve connected to a valve actuator in a combustion cylinder of an internal combustion engine.

The gas exchange valve control device according to the invention having the features of claim 1 has the advantage of reducing the number of electric control valves per valve actuator pair by replacing the first electric control valve of one valve actuator in the valve actuator pair with a simple switching valve. And the switching valve controls the hydraulic pressure in the second working chamber using the hydraulic pressure in the second working chamber of the other valve actuator. Additionally in accordance with a preferred embodiment of the present invention, the second electrical control valve of the valve actuator pair is a simple check valve, i.e. a check that connects the second actuating chamber of one valve actuator to a second electrical control valve assigned to another valve actuator. If replaced with a valve, two magnetic valves per valve actuator pair may be omitted. Electrical control valves such as these are very expensive because electrical control valves, typically formed of 2 / 2-way magnetic valves, have to realize an extremely short switching time, approximately 0.3 ms in the actual open cross section of 3 mm ² . Reducing the number of electrical control valves within will certainly save money. The smaller number of electrical control valves also reduces the number of final stages and the cost of the electrical cable for the control valves, which further reduces the cost. A small number of electrical control valves do not require much electrical energy and reduce the likelihood of a device failure. Since the volume of the simple switching valve is smaller than that of the magnetic valve, the space required for placing the device in the vehicle can be reduced. A pair of valve actuators controlled by a single first electric control valve and two or one second electric control valve is provided with two gas exchange valves in the same manner, ie two inlet valves or two reliefs used in the same combustion cylinder. A valve actuator for actuating the valve.

The measures described in the dependent claims enable further preferred embodiments and refinements of the gas exchange valve control device set forth in claim 1.

According to a preferred embodiment of the invention, a switching valve is arranged in the connection line between the second working chambers of both valve actuators of the valve actuator pair. When the changeover valve formed by a 2 / 2-way valve, which can be operated by electric motors, electromagnetics or hydraulics, is opened, the second actuating chamber of one valve actuator provides hydraulic pressure through the second actuating chamber of the other valve actuator. As a result, the regulating piston of the valve actuator moves in the opening direction of the gas exchange valve. By appropriately selecting the opening timing of the switching valve, different opening times of the gas exchange valve actuated by the valve actuator can be realized or the gas exchange valves can be kept closed when necessary. The single primary electric control valve of the valve actuator pair should be designed to control the overall volume flow at the extreme and require both valve actuators of the valve actuator pair to perform simultaneous or offset, but always parallel strokes. Shall be. By controlling the second electrical control valve, different closing times of both gas exchange valves can be realized. As mentioned above, if one of the two second electric valves is replaced with a check valve, the gas exchange valves are closed at the same time.

According to a preferred embodiment of the invention the switching valve is a hydraulically actuated 2/2 directional valve with two hydraulic control inputs and is configured such that the valve opens only upon application of both control inputs. One control input is connected to a second working chamber connected to a single first electrical control valve and the other control input is applied to the outlet of the further switching valve on the inlet side by means of hydraulic pressure. The second actuating chamber of the valve actuator connected to the diverter valve is placed directly on the hydraulic source via the diverter valve. As soon as the single first electrical control valve is controlled, the hydraulic pressure controlled in the second working chamber by the control valve also occurs in one control input of the switching valve. The changeover valve can be opened at any point in time by the application of a second control input, and as the changeover valve is switched, the fluid exits directly from the hydraulic source and flows into the second working chamber of the other valve actuator. This embodiment has the advantage that the single first electric control valve of the valve pair only needs to be sized to supply fluid to the single valve actuator and does not have to switch the entire flow rate for controlling both valve actuators. Instability in the stroke movement of one valve actuator is also prevented, which is connected to the other valve actuator during the stroke movement of the regulating piston of the valve actuator, thereby allowing additional fluid to be drawn in the second actuating chamber of the subsequent valve actuator. Can occur as required.

With further switching valves in accordance with a preferred embodiment of the present invention, since all the switching valves of the existing valve pair are opened, a single additional switching valve is provided in the apparatus, which has the advantage of reducing manufacturing costs and space.

According to a preferred embodiment of the present invention the further switching valve is actuated by hydraulic pressure by means of which the valve inlet is connected via a single check valve to a second working chamber of a valve pair connected to a single first electric control valve. Optionally the further switching valve may be pressurized via an external hydraulic source, for example a low pressure circuit of the internal combustion engine.

The invention is explained in more detail below by the examples shown in the drawings.

The apparatus for controlling the gas exchange valve in the combustion cylinder of the internal combustion engine, shown in the circuit diagram in FIG. 1, is configured to control a total of eight gas exchange valves 10 as shown in FIG. 3, each of which is a four cylinder It is arranged in one combustion cylinder of a four clock internal combustion engine. The gas exchange valve 10 may be an inlet valve or a relief valve of the combustion cylinder. The apparatus comprises a plurality of hydraulic valve actuators 11, in this embodiment a total of eight valve actuators 11, each one of which operates one gas exchange valve 10. All valve actuators 11 comprise an actuating cylinder 12, to which the regulating piston 13 is movably guided axially. The regulating piston 13 divides the actuating cylinder 12 into a hydraulic pressure chamber or actuating chambers 121, 122 restricted by the regulating piston and is fixedly connected to the valve tappet 14 of the gas exchange valve 10. . In FIG. 3, the valve actuator 11 is schematically enlarged with the open gas exchange valve 10. The valve tappet 14 supports the valve sealing surface 15 at its end opposite the regulating piston 13, which is formed on the valve seat surface 17 formed in the cylinder head 16 of the combustion cylinder of the internal combustion engine to control the open cross section. To interact with. The working cylinder 12 comprises a total of three hydraulic connections, of which two hydraulic connections 122a and 122b lead to the upper pressure chamber or the second operating chamber, and one hydraulic connection 121a connects to the lower pressure chamber. Or to the first working chamber 121.

The apparatus further comprises a pressure supply device 20, the output 201 of the supply device forming a hydraulic source for supplying pressure to the valve actuator 11. The pressure supply device 20 includes a high pressure pump 21 for transferring fluid from the fluid reservoir 18, a check valve 22 disposed on the discharge side of the high pressure pump 21, and attenuating pulses and storing energy. It includes a reservoir 23 for. The output 201 of the pressure supply device 20 tapped between the check valve 22 and the reservoir 23 is via the line 24 the first operating chamber 121 in all eight valve actuators 11 in total. Since it is connected to the hydraulic connection portion 121a of, the first operating chamber 121 of the valve actuator 11 continuously receives the high hydraulic pressure generated at the output 201 of the pressure supply device 20.

Of the total eight valve actuators 11, two valve actuators 11 are integrated into a pair of valve actuators, which control two inflow valves or two relief valves, respectively, in the same combustion cylinder. The combustion cylinder is shown in FIG. 1 with the corresponding control means by the dashed edge 19 of the valve actuator pair. For the sake of simplicity, the valve actuator 11 of the valve actuator pair is represented below by 11a and 11b and the detailed description is limited to a pair of valve actuators assigned to one combustion cylinder. However, this description applies in the same way to the remaining valve actuator pairs assigned to the three combustion cylinders.

The fluid connection 122a of the second working chamber 122 of the valve actuator 11a is provided with a pressure supply device 20 via a first electric control valve 25 formed as a 2 / 2-way magnetic valve subjected to spring restoring force. Is connected to a line 24 leading to the output 201 of the valve, while the fluid connection 122b of the second actuating chamber 122 of the valve actuator 11a is likewise formed as a 2 / 2-way magnetic valve subjected to spring restoring force. The second electrical control valve 26 is placed. The output side of the second electrical control valve 26 is connected to a return line 27 leading to the fluid reservoir 18. The fluid connection 122a of the second actuating chamber 122 of the valve actuator 11b is connected to the fluid connection 122b of the valve actuator 11a via a connection line 28, which is to be hydraulically opened to the connection line. And a switching valve 29 which is spring-resilient. The fluid connection 122b of the second working chamber 122 of the valve actuator 11b is likewise connected to the inlet of the second electric control valve 26 via the check valve 30. The changeover valve 29 comprises a hydraulic control input 291 which is connected via a control line 31 to the outlet of an additional switchable valve 32 which is electromagnetically operable. The inlet side of the further switching valve 32 is connected to the second working chamber 122 of the valve actuator 11a via a check valve 33. Optionally, however, the inlet side of the further switching valve 32 may be connected to the output 201 of the pressure supply device 20 or to the low pressure circuit of the internal combustion engine. The outlet side of the further diverting valve 32 is placed at all control inputs 291 of the diverting valve 29 for all valve actuator pairs, through the corresponding control line 31. When the switching valve 32 is formed as a 2/2 directional magnetic valve subjected to spring restoring force similarly to the embodiment of FIG. 1, it is a 2/2 directional magnetic valve subjected to spring restoring force to relief the pressure of the control line 31. A relief valve 35 formed must be provided, one valve connection of the relief valve being connected to the control line 31 and the other valve connection to the fluid reservoir 18. The relief valve 35 may be omitted when the switching valve 32 is formed as a 3 / 3-way magnetic valve subjected to spring restoring force as shown in FIG. 2. In this case, of the three valve connections, the valve inlet is connected to the second working chamber 122 of the valve actuator 11a via the check valve 33 or to the output 201 of the pressure supply device 20, respectively. The first valve outlet is connected to the control line 31 and the second valve outlet to the fluid reservoir 18.

When the gas exchange valve 10 is closed, the valve actuators 11a and 11b of the pair of valve actuators take their basic positions, in which the first electric control valve 25 is the first of the valve actuators 11a. The second working chamber 122 is closed from the output 201 of the pressure supply device 20, and the second electric control valve 26 returns the second working chamber 122 of the valve actuator 11a to the return line 27. Connect to The second working chamber 122 of the valve actuator 11b is likewise placed in the return line 27 via the check valve 30 and the open second electrical control valve 26. Both switching valves 29 and 32 take their closed position by the restoring action of the restoring spring. By means of the system pressure in the first working chamber 121, the regulating piston 13 moves to its basic position to the maximum and keeps the gas exchange valve 10 closed through the valve tappet 14. In the illustrated embodiment, the control valves 25 and 26 are no current and the switching valve 29 is no pressure.

Since the second electric control valve 26 is first switched to its closed position in order to open the gas exchange valve 10, both second working chambers 122 of both valve actuators 11a and 11b are closed. The relief valve 35 is switched to its closed position. At the same time, since the first electric control valve 25 is switched to its operating or open position, the second working chamber 122 of the valve actuator 11a is connected to the pressure supply device 20, System pressure that can be provided to the output 201 now also occurs in the second working chamber 122 of the valve actuator 11a. Since the piston face of the regulating piston 13 restricting the first actuation chamber 121 is smaller than the piston face of the regulating piston 13 restricting the second actuation chamber 122, the regulating piston 13 is right in FIG. 1. A movement force is generated to move the gas exchange valve 10 so that the gas exchange valve 10 is opened. The size of the opening stroke of the gas exchange valve 10 depends on the opening duration and the opening speed of the first electric control valve 25.

Later or at the same time, if the further switching valve 32 is controlled by the first electric control valve 25, the switching valve is connected to the switching valve 29 via the check valve 33 and the open additional switching valve 32. The system pressure reaching the control input 291 switches the switching valve 29 to the restoring spring force, thereby opening the switching valve 29. Fluid flows from the second actuating chamber 122 of the valve actuator 11a into the second actuating chamber 122 of the valve actuator 11b so that the regulating piston 13 of the actuator is displaced in the valve opening direction. Since the total fluid flow now flows through the first electric control valve 25, the first electric control valve 25 must be designed for maximum volume flow through both valve actuators 11a and 11b. After the connection of the second valve actuator 11b, the gas exchange valve 10 operated by the valve actuator 11b moves in correspondence with the control of the first electric control valve 25, so that both valve actuators 11a and 11b The regulating piston () realizes simultaneous or offset, parallel strokes, depending on the opening timing of the switching valve (29).

In order to keep the gas exchange valve 10 in its open position, the first electric control valve 25 is switched again (connected with no current in the embodiment of FIG. 1), so that the control valve is connected to the valve actuator 11a. The second working chamber 122 is separated from the line 24 of the pressure supply device 20.

If the gas exchange valve 10 is to be closed again after a certain opening time, the second electric control valve 26 is also switched (connected with no current in the embodiment of Fig. 1), so that the control valve is connected to both valve actuators 11a. 11b) connects working chamber 122 to return line 27. Due to the system pressure in the first actuating chamber 121 of the valve actuators 11a and 11b, the regulating piston 13 is in the actuating cylinder 12 of both valve actuators 11a and 11b in the basic position shown in FIG. Returning to, the gas exchange valve 10 is closed with the same closing time.

If a different closing time is to be implemented, the check valve 30 is replaced by an additional second electric control valve 26, which is likewise formed of a 2 / 2-way magnetic valve and the inlet side of which is a valve actuator 11b. Is connected to the second working chamber 122 and its discharge side is directly connected to the return line 27.

Instead of a switching valve 29 which can be hydraulically opened between the two second working chambers 122 of both valve actuators 11a and 11b, a switching valve which can be opened by an electric motor or electromagnetic may be used. have. An additional diverting valve 32 may be replaced by an electric actuator, which opens all the diverting valves 29 directly by electric motors or likewise hydraulically.

The gas exchange valve control device in the combustion cylinder of the internal combustion engine, shown section by section in FIG. 2, has a second actuation of both valve actuators 11a, 11b in which a switching valve 29 as described above is used in comparison with the device described in FIG. 1. With the connection line 28 between the chambers 122, it is transformed into being replaced by a hydraulically controlled switching valve 34, which switches the pressure supply of the second working chamber 122 of the valve actuator 11b. Directly to line 24 to output 201 of device 20. The control valve 34 embodied as " And-gate " in the control plane includes two hydraulic control inputs 341 and 342, both of which must be hydraulically operated in order to switch the switching valve 34. . The diverter valve 34 has a hydraulic restoring input 343 which receives hydraulic pressure to divert the diverter valve 34 to the closed position shown in FIG. 2, for which a line to the output 201 ( The pressure supply device 20 is connected to 24. The control input 341 of the switching valve 34 is connected to the fluid connection 122b of the second working chamber 122 of the valve actuator 11a and the other control input 342 is connected by the control line 31 to the electrical connection. It is connected to a controlled further switching valve 32. The electrically controlled switching valve 32 is here formed as a 3/3 directional magnetic valve with spring restoring force, the second valve outlet of which is connected to the fluid reservoir 18. According to the connecting position of the 3 / 3-way magnetic valve, pressure is formed in the control line 31 and the pressure can be maintained or reduced. However, the switching valve 32 may be formed as a 2 / 2-way magnetic valve as in FIG. In this case, a relief valve 35 formed as a 2 / 2-way magnetic valve is provided as in FIG. 1. In addition, since the switching device according to FIG. 2 is not deformed, the same components are provided with the same reference numerals.

If there is pressure in the second actuating chamber 122 of the valve actuator 11a, the control input 341 is hydraulically loaded, so that at each point in time the diverter valve 34 has an additional diverter valve 32 It can be opened by being controlled. The opening of the switching valve 34 causes the fluid to flow directly from the line 24 into the second working chamber 122 of the valve actuator 11b and the regulating piston 13 in the working cylinder 12 of the valve actuator 11b As it moves to the regulating piston 13 in the actuating cylinder 12 of the valve actuator 11a in the parallel stroke, the gas exchange valve 10 actuated by the valve actuator 11b is correspondingly opened. In the case of the control device modified as described above, the first electric control valve 25 is sized only for supplying the fluid to the valve actuator 11a, which means that the valve actuator 11b is connected to the pressure supply device 20. Because it is supplied directly by At the same time, instability during the stroke movement of the valve actuator 11a is prevented, and this instability is added in the valve actuator 11b during the stroke of the valve actuator 11a during the connection of the valve actuator 11b in the control device according to FIG. 1. Of fluid may be required.

The above description also applies to the control device according to FIG. 2, which corresponds to a further valve pair, not shown, for another combustion cylinder of the internal combustion engine.

Claims (15)

A device for controlling a gas exchange valve 10 in a combustion cylinder of an internal combustion engine, the apparatus having a hydraulic valve actuator 11 each assigned to one gas exchange valve 10, the hydraulic valve actuators each being a gas exchange valve. Regulating piston 13, which acts on, and two hydraulic actuating chambers 121, 122 limited by the regulating piston 13, among the actuating chambers, acting in the closing direction on the gas exchange valve 10. The first working chamber 121 is connected to the hydraulic source 20 to be continuously filled with the pressurized fluid and the second working chamber 122 acting in the opening direction to the gas exchange valve 10 has an inflow side thereof. To a gas exchange valve control device which may be filled with pressurized fluid by a first electrical control valve 25 placed in a circle 201 and empty by a second electrical control valve 26 placed on a low pressure level. There Standing,  Each pair of valve actuators 11a and 11b is provided with a single first electric control valve 25, the discharge side of the electric control valve being the second actuating chamber 122 of the valve actuator 11a of one of the two valve actuators. ), The second actuating chamber 122 of the other valve actuator 11b is by means of a switching valve 29 which can switch between a closed position and an open position, and a single first electric control valve 25 Gas exchange valve control device, characterized in that it is filled with a fluid by the hydraulic pressure in the second working chamber (122) of one valve actuator (11a) connected to. 2. The valve actuator pair according to claim 1, wherein the pair of valve actuators are assigned to two gas exchange valves 10 in the same manner, ie two relief valves or two inlet valves in the same combustion cylinder 19. A gas exchange valve control device comprising: 11b). 3. The switching valve (29) according to claim 1 or 2, characterized in that the switching valve (29) is arranged in the connection line (28) between the second actuating chambers (122) of both valve actuators (11a, 11b) of the valve actuator pair. Gas exchange valve control device. 4. The gas exchange valve control apparatus according to claim 3, wherein the switching valve (29) is an electric motor or electromagnetically actuated 2/2 directional valve. 4. The valve outlet of claim 3, wherein the switching valve 29 is a hydraulically actuated 2/2 directional valve and includes one control input, the control input of the additional switching valve 32 acting by hydraulic pressure. Gas exchange valve control device, characterized in that applied to. 6. The gas exchange valve control apparatus according to claim 5, wherein the 2/2 directional valve includes a restoring spring (292) for returning to the closed position. 3. The switch valve 34 according to claim 1 or 2, wherein the switching valve 34 is a hydraulic 2/2 directional valve having two hydraulic control inputs, and the switching valve 34 is applied when both control inputs 341 and 342 are applied. Is designed to open only, and one control input 341 is connected to a single first electrical control valve 25, to the second operating chamber 122 of one valve actuator 11a, the other control input 342. Is applied to the discharge part of the additional switching valve 32 in which the inflow side is actuated by hydraulic pressure, the inflow side of the switching valve 34 to the hydraulic source 201 and the discharge side to the second operation of the other valve actuator 11b. Gas exchange valve control device, characterized in that connected to the chamber (122). 8. The gas exchange valve control according to claim 7, wherein the 2/2 directional valve includes a hydraulic restoration control input 343 for returning to the closed position, the restoration control input being connected to a hydraulic source 201. Device. 9. The second actuating chamber of claim 5, wherein the valve inlet is connected to a single first electric control valve 25 to apply hydraulic pressure to the further switching valve 32. Gas exchange valve control device, characterized in that connected to (122) via a check valve (33). 10. The relief valve (10) according to claim 9, wherein the further switching valve (32) is formed as a 2/2 directional magnetic valve receiving a spring restoring force, the valve discharge portion preferably having a relief valve formed as a 2/2 directional magnetic valve receiving a spring restoring force 35) is connected, characterized in that a connection to the fluid reservoir (18) by the relief valve can be made. 10. The gas exchange valve according to claim 9, wherein the further switching valve (32) is formed as a 3/3 directional magnetic valve subjected to a spring restoring force, the second valve outlet of which is connected to the fluid reservoir (18). controller. 12. A single second electrical control valve 26 is provided for each one of said valve actuator pairs 11a, 11b, the valve inlet of which is a single first electrical control. Directly connected to the second working chamber 122 of one valve actuator 11a, connected to the valve 25, connected to the second working chamber 122 of the other valve actuator 11b via a check valve 30. Gas exchange valve control device, characterized in that. 12. The two second electrically controlled valves 26 are provided for one valve actuator pair 11a, 11b, respectively, wherein the inlet side of each one of them is Gas exchange valve control device, characterized in that it is connected to the second working chamber (122) of both valve actuators (11a, 11b). 14. The valve according to any one of claims 5 to 13, wherein at least one valve pair (11a, 11b) is provided per combustion cylinder, and the discharge side of the further diverting valve (32) is each one valve actuator pair (11a, 11b). Gas exchange valve control device, characterized in that it is connected to all of the hydraulic switching valves (29) assigned. The gas exchange valve control device according to claim 9, wherein the valve inlets of the further diverting valve are connected to all valve actuator pairs.