WO2002066816A1

WO2002066816A1 - Self-cleaning valves in air entry or waste gas systems in internal combustion engines

Info

Publication number: WO2002066816A1
Application number: PCT/DE2002/000565
Authority: WO
Inventors: Ralph Krause
Original assignee: Robert Bosch Gmbh
Priority date: 2001-02-20
Filing date: 2002-02-18
Publication date: 2002-08-29
Also published as: DE10108043A1; EP1366281A1; DE10108043B4

Abstract

The invention relates to a valve (15) for fluid flows in air entry or waste gas systems in internal combustion engines, comprising a valve plate (1) and a valve seat (2) in a housing (10). The lift movement (14) of the valve plate (1) corresponds to a rotational movement (13) of the valve plate (1) in relation to the valve seat (2) in order to control the incoming or outgoing flow of a flowing medium or several flowing media¿.?

Description

Self-cleaning valves in the supply air or exhaust system on internal combustion engines

Technical field

The invention relates to a self-cleaning valve, in particular in a deceleration engine. Valves are used, for example, to mix gas flows in the exhaust gas recirculation system of modern motor vehicle internal combustion engines. For example, burned exhaust gas is mixed with a fresh air stream to reduce the peak combustion temperature. The exhaust gas recirculation effectively reduces the temperature-dependent NO _x emissions of the internal combustion engine. The exhaust gas recirculation system contains an exhaust gas recirculation valve that controls the amount of exhaust gas to be recirculated.

State of the art

DE 198 25 656 AI relates to an exhaust gas recirculation valve for internal combustion engines, which has a valve passage with valve seat surface and a valve member with an annular surface assigned to the valve seat surface and facing. The annular surface of the valve member is formed on an axially projecting annular collar on the top of the valve member, while the valve seat surface of the housing part is provided on the lower side thereof. The object of this invention is to design an exhaust gas recirculation valve in such a way that a flawless opening and / or measuring function between the valve member and the valve seat is ensured. For this purpose, the contamination of the sealing function elements is avoided by constructive design of the sealing function elements. These are passive measures, no active self-cleaning of the exhaust gas recirculation valve.

EP 0 856 657 A2 discloses an exhaust gas recirculation valve for an internal combustion engine, with a housing which contains an exhaust gas duct with a valve seat, which is controlled by a valve member and whose actuating member is displaceably guided in the housing and is actuated by an adjusting device. The adjusting device has a rotary working drive and a gear-changing device connected downstream of the drive, by means of which the rotary drive movement of the drive can be converted into a translational movement of the actuating member with valve member. The valve member therefore carries out only a translatory and not a rotational movement.

DE 196 03 592 Cl relates to a valve control for an internal combustion engine, in particular for an exhaust gas recirculation valve, with an electrically controllable rotary magnet, with an actuator arrangement which can be driven by a rotary magnet and which can be connected to a valve disk which can be guided on a valve rod. With a lifting device of the actuator arrangement, a rotary movement that can be controlled by the rotary magnet can be converted into a lifting movement of the valve disk. The axial guide is designed as a longitudinal groove bearing, which forms an anti-rotation device. Rotation of the valve plate is prevented in this invention.

From EP 0 740 066 AI an exhaust gas recirculation valve is known which has a coil device and a ball bearing. The ball bearing supports a guide element which, in response to an electrical actuation of the coil device, carries out a translational movement together with an actuating element of the valve, as a result of which the valve opens. A rotational movement is not disclosed.

Exhaust gas recirculation valves on internal combustion engines can cause contamination of the valve functional elements in certain operating states or in the case of incorrectly matched combustion. In connection with oil from the crankcase ventilation and or soot particles, sticking to the sealing function elements can occur, which results in sluggishness or even failure of the component. Furthermore, local detachment of the impurities on the valve functional elements results in leaks when the valve is closed.

Presentation of the invention

Contamination of valves can be prevented by a self-cleaning mechanism of the valves. In the present invention, such self-cleaning takes place in a valve in an internal combustion engine, which contains a valve plate and a valve seat in a housing, by superimposing a lifting movement of the valve plate on a rotary movement of the valve plate relative to the valve seat. If only one lifting movement is carried out, this results in normal stresses which do not lead to an even load on the accumulated dirt between the valve plate and valve seat. Rather, it can become local due to the normal stresses Detachment of the dirt and thereby local leaks occur when the valve is closed. Due to the superimposed rotary motion, shear stresses are evenly distributed on the contact surface between the valve plate and valve seat, through which contamination or contamination - between the valve plate and valve seat are evenly removed. Accordingly, the valve is self-cleaning.

An advantage of the present invention is accordingly that this self-cleaning mechanism removes the contaminants or contaminants carried in the flowing medium to be controlled, which accumulate on a valve without a cleaning mechanism between the functional elements of the valve plate and the valve seat and can thus lead to the component being inoperable ,

It is also advantageous that the valve according to the invention activates the self-cleaning mechanism each time it is opened and closed.

In one embodiment of the invention, the rotary movement of the valve plate relative to the valve seat is non-linear to the lifting movement. A non-linear coupling of the rotary movement with the stroke movement can be advantageous, for example, in such a way that only a small stroke is realized at the beginning of the opening movement of the valve and a large stroke at the end. As a result, even small amounts of a flowing medium can be metered using the valve.

The valve according to the invention can be designed such that it is actuated by a rotationally operating drive which is firmly connected to the housing. In this context, rotating work means that the drive applies a torque that can be transmitted to the valve via a shaft.

In one embodiment of the invention, a return spring engages the shaft of the rotary drive, which closes the valve if the drive is defective. When the valve opens, the torsion spring is tensioned so that it closes the valve if the actuator malfunctions.

In one embodiment of the invention, a shaping device converts a movement of the rotationally operating drive into the superimposed lifting and rotating movement. The forming device can contain a rotary motion transmission element and a motion conversion element. The rotary motion transmission member serves to transmit the rotary motion of the drive to the motion conversion member. The motion converting member sets the one transmitted by the rotary motion transmitting member Rotational movement in the stroke movement superimposed by a rotary movement according to the invention. A lifting shaft can be firmly connected to the motion conversion element. At the end of the lifting shaft, the valve disk is fixed in a rotationally rigid manner. The superimposed rotary and lifting movement carried out by the movement conversion element is transmitted to the valve plate via the lifting shaft. The valve disk-lifting shaft connection must accordingly be able to absorb forces both in the radial and in the axial direction without loosening. Due to the superimposed rotary and lifting movement carried out by the lifting shaft, the valve disk lifts off the valve seat during the opening process and releases an opening cross section. The greater the angle of rotation of the rotary drive, the larger the cross-section of the opening and also the flow of the flowing medium through the valve. According to a further advantageous embodiment of the invention it is provided that the rotary motion transmission member engages in an opening of the motion conversion member in a form-fitting manner and displaceable in the axial direction. If the movement conversion member carries out a lifting movement (superimposed by a rotary movement), the rotary movement transmission member moves in the opening in the axial direction, but remains stationary relative to the housing. The opening must be of a suitable depth so that the rotary motion transmission element does not move completely out of the opening even when the valve is opened to the maximum (maximum stroke). It can also be expedient that the rotary motion transmission element and the motion conversion element are firmly connected and that the rotary motion transmission element engages in a form-fitting manner in an opening located in the rotary drive.

According to a further advantageous embodiment of the invention it is provided that the conversion of the movement of the rotationally operating drive into the superimposed lifting and rotating movement of the valve plate takes place with the aid of interlocking threads on the movement conversion member and the housing. The housing absorbs the reaction force of the resulting lifting and rotating movement between the threads.

It can also be expedient for the conversion of the movement and of the rotationally operating drive into the superimposed lifting and rotating movement of the valve plate to take place with the aid of at least one, preferably at least two, transmission bodies. The reaction force is not absorbed directly between threads, but via the transmission body. The transmission bodies can be designed to be rolling or sliding. Examples of rolling transmission bodies are balls or cylinders. Examples of sliding transmission bodies are cuboids or trapezoidal sliding elements. The transmission bodies can advantageously be stationary on the movement conversion element and can move in a helical groove in the housing. However, it can also be expedient for the transmission bodies to be stationary in the housing and to be able to move in a helically shaped groove on the movement conversion element.

According to a further advantageous embodiment of the invention, it is provided that the groove does not have a constant but a variable slope. As described above, this results in a non-linear coupling of the lifting and rotating movements of the valve plate relative to the valve seat. For example, it is possible to implement only a small stroke (flat slope) at the beginning of the opening movement and a large stroke (large slope) at the end. This has the advantages that, on the one hand, the self-cleaning effect is further enhanced with such a groove and, on the other hand, the small quantity metering of the lift valves, which naturally have a degressive throughput characteristic, is improved.

The valve according to the invention can be used both to control the flow of a flowing medium and to control the mixture of several flowing media. Furthermore, it can be used to open in the flow direction of a flowing medium to be metered or to open against the flow direction of a flowing medium.

Furthermore, the invention relates to the use of a valve in an internal combustion engine, the valve containing a valve plate and a valve seat in a housing, and a rotary movement of the valve plate relative to the valve seat being superimposed on a lifting movement of the valve plate. The valve is used to control the inflow or outflow of at least one flowing medium. The valve can be used in particular in an internal combustion engine to control the supply air or the extract air. Possible flowing media are exhaust gas, air or a fuel-air mixture. For example, the valve can be used as an exhaust gas recirculation valve.

drawing

The invention is explained in more detail below with the aid of the drawing.

It shows:

1 shows the construction of a self-cleaning exhaust gas recirculation valve with opening against the exhaust gas flow and without fresh air throughput, FIG. 2 shows the construction of a self-cleaning exhaust gas recirculation valve with opening with the exhaust gas flow and without fresh air throughput,

Figure 3 shows the structure of a self-cleaning exhaust gas recirculation valve with an opening with the exhaust gas flow and with fresh air throughput and

Figure 4 shows the structure of a self-cleaning exhaust gas recirculation valve with an opening against the exhaust gas flow and with fresh air throughput.

variants

Figure 1 shows the structure of a self-cleaning exhaust gas recirculation valve with an opening against the exhaust gas flow and without fresh air throughput. The valve is shown in the open position (right half) and in the closed position (left half). The rotationally operating drive 8 is seated on the housing 10. The shaft of the drive 8 is fixedly connected to the rotary motion transmission element 6. In this example, a square located on the shaft of the drive 8 serves as a rotary motion transmission element 6. This rotary motion transmission element engages in a form-fitting manner in the correspondingly designed opening 11 of the motion conversion element 5. When the rotary drive 8 rotates, the rotary motion of the shaft of the drive is transmitted to the motion conversion member 5 via the rotary motion transmission member 6. If the movement conversion ghed 5 rotates, it is guided through the thread 12 on the movement conversion member 5 and in the housing 10 so that it carries out a superimposed rotary and lifting movement (13 and 14). The lifting shaft 3, which is mounted in a lifting shaft bearing 4, transmits this superimposed rotary and lifting movement (13 and 14) to the valve plate 1, which thereby rotates from the valve seat 2 (opening of the valve 15) or rotates towards the valve seat 2 (closing the Valve 15). In the event of a superimposed rotary and lifting movement (13 and 14) of the movement conversion element 5, the opening 11, in which the rotary movement transmission element 6 is located in a form-fitting manner, shifts in the vertical direction relative to the rotary movement transmission element 6, so that the opening 11 becomes larger when the valve 15 is opened and becomes smaller when it is closed. The rotary motion transmission member remains stationary relative to the housing 10. The rotational movement of the valve plate 1 relative to the valve seat each time the valve 15 opens and closes, and evenly distributed shear stresses are built up on the contact surface between valve plate 1 and valve seat 2. These shear stresses cause contamination or soiling to be evenly removed between valve plate 1 and valve seat 2. The greater the angle of rotation of the rotationally operating drive 8, the larger the opening cross section and thus the throughput of gas flowing through the valve 15. When the valve 15 opens, a return spring 7 engaging the shaft of the rotary drive is tensioned. The return spring 7 is designed and biased so that the valve 15 is closed by the torsion spring 7 when the drive 8 is inoperative. In this example, the valve disk 1 moves against the flow direction of the exhaust gas 9 when the valve 15 is opened. In this embodiment, the valve 15 controls only a gas flow, such as the exhaust gas 9.

Figure 2 shows the structure of a self-cleaning exhaust gas recirculation valve with an opening with the exhaust gas flow and without fresh air throughput. The structure of the valve 15 corresponds essentially to that in FIG. 1. In contrast to FIG. 1, FIG. 2 shows a valve 15 in which the valve plate 1 opens with the flow direction of the exhaust gas 9 relative to the valve seat 2. In this embodiment too, the valve 15 controls only one gas flow.

Figure 3 shows the structure of a self-cleaning exhaust gas recirculation valve with an opening with the exhaust gas flow and with fresh air throughput. The structure of the valve 15 corresponds essentially to that in FIG. 1. In contrast to FIG. 1, FIG. 3 shows a valve 15 in which (as in FIG. 2) the valve plate 1 opens with the flow direction of the exhaust gas 9 relative to the valve seat 2. Another difference is that fresh air 16 flows through the valve 15 and, when the valve 15 is open, there is a mixed flow of exhaust gas and fresh air 17, that is to say an admixture of one flowing medium to another. This variant of the valve according to the invention could, for example, be used as an exhaust gas recirculation valve in which exhaust gas is mixed into a fresh air stream.

FIG. 4 shows the construction of a self-cleaning exhaust gas stirring valve with an opening against the exhaust gas flow and with fresh air throughput. The structure of the valve essentially corresponds to that in FIG. 1. In contrast to FIG. 1, FIG. 4 shows a valve 15 in which fresh air 16 flows through valve 15 (as in FIG. 3) and in which valve 15 opens when valve 15 is open mixed flow of exhaust gas and fresh air 17 results. With this- In this embodiment, the valve plate 1 opens relative to the valve seat 2 against the flow direction of the exhaust gas 9.

LIST OF REFERENCE NUMBERS

1 valve plate

2 valve seat

3 lifting shaft

4 lifting shaft bearing

5 Movement converter

6 rotary motion link

7 return spring

8 drive

9 exhaust gas

10 housing

11 opening

12 threads

13 rotary motion

14 stroke movement

15 valve

16 fresh air

17 Flow of exhaust gas and fresh air

Claims

claims

1. Valve for fluid flows in supply air or exhaust systems on internal combustion engines, with a valve plate (1) and a valve seat (2) in a housing (10), characterized in that a stroke movement (14) of the valve plate (1) one

Rotary movement (13) of the valve plate (1) relative to the valve seat (2) for controlling the inflow or outflow of a flowing medium or a plurality of flowing media is superimposed.

2. Valve according to Anspmch 1, characterized in that the rotary movement (13) is non-linear to the lifting movement (14).

3. Valve according to Anspmch 1, characterized in that the valve (15) is actuated by a rotatably operating drive (8) connected to the housing (10).

4. Valve according to Anspmch 3, characterized in that a return spring (7) closes the valve (15) if the drive (8) is defective.

5. Valve according to Anspmch 3, characterized in that a shaping device forms a movement of the rotary drive (8) into the superimposed lifting and rotating movement (13, 14) of the valve plate (1).

6. Valve according to Anspmch 5, characterized in that the forming device includes a rotary motion transmission member (6) and a motion conversion member (5).

7. Valve according to Anspmch 6, characterized in that a lifting shaft (3) with the movement conversion member (5) is fixedly connected and at the end of the valve plate (1) is rotationally fixed.

8. Valve according to Anspmch 6, characterized in that a key, a disc spring, a slide spring, a multi-groove profile, a serration profile or a polygonal shaft profile connection is used as the rotary motion transmission member (4).

, Valve according to Anspmch 6, characterized in that a square located on the shaft of the rotationally operating drive (8) is used as the rotary motion transmission member (6).

10. Valve according to Anspmch 6, characterized in that the rotary motion transmission member (6) engages positively and displaceably in the axial direction in an opening (11) of the motion conversion member (5).

11. Valve according to Anspmch 6, characterized in that the rotary motion transmission member (6) and the motion conversion member (5) are fixedly connected and that the rotary motion transmission member (6) in a rotationally operating drive (8) contained opening (11) rotationally rigid, intervenes positively.

12. Valve according to Anspmch 6, characterized in that the implementation of the movement of the rotary drive (8) in the superimposed lifting and rotating movement (14, 13) of the valve plate (1) with the help of interlocking threads (12) on the motion conversion member (5) and the housing (10).

13. Valve according to Anspmch 6, characterized in that the implementation of the movement of the rotary drive (8) in the superimposed lifting and rotating movement (14, 13) of the valve plate (1) is carried out with the aid of at least one transmission body.

14. Valve according to Anspmch 13, characterized in that the transmission body is stationary on the motion conversion member (5) and can move in a helical groove in the housing (10).

15. Valve according to Anspmch 13, characterized in that the transmission body is stationary in the housing (10) and can move in a helical groove on the motion conversion member (5).

16. Valve according to Anspmch 13, characterized in that the transmission body performs a rolling movement or a sliding movement.

17. Valve according to Anspmch 14 or 15, characterized in that the groove has a variable slope.

18. Valve according to Anspmch 17, characterized in that the slope of the groove at the beginning of an opening movement of the valve (15) is small and increases towards the end.

19. Use of a valve in an internal combustion engine, the valve (15) containing a valve plate (1) and a valve seat (2) in a housing (10), characterized in that a lifting movement (14) of the valve plate (1) is a rotary movement (13) of the valve plate (1) is superimposed relative to the valve seat (2) and the valve (15) is used to control the inflow or outflow of at least one flowing medium.

20. Use according to Anspmch 19, characterized in that at least one flowing medium is exhaust gas, air or a fuel-air mixture.