EP2017456A1 - Exhaust gas recirculation system - Google Patents

Abstract

The exhaust gas feedback unit has a cooler (10) with bypass (12) and cooler (16) and bypass (18) valves operated coaxially from the same rotational or vacuum drive (44).

Description

Technical area

The invention relates to an exhaust gas recirculation system according to the preamble of claim 1.

In order to improve the emission values and to reduce the fuel consumption, it has long been known in the field of internal combustion engines to recirculate the exhaust gas emitted by the engine into the air supply system of the internal combustion engine. Since the temperature of the exhaust gases varies depending on the operating state of the engine, it is necessary to control the temperature of the exhaust gas so as to be cooled particularly in the warm state of the engine.

State of the art

An exhaust gas recirculation system according to the preamble of claim 1 is known from DE 199 06 401 Applicant is aware of this and has a radiator through which the exhaust gas flows, a bypass which bypasses the radiator, and a valve which selectively closes the radiator inlet or the bypass. This can be controlled depending on the operating condition of the engine, whether the Exhaust gas flows through the radiator and is thus cooled, or whether the radiator, for example in the cold-running phase of the engine, is bypassed, so that the exhaust gas maintains its outlet temperature.

The DE 197 33 964 A1 discloses a valve assembly for controlling a recirculated exhaust gas flow wherein the two valve discs have a common actuating mechanism for opening and closing the radiator inlet and for opening and closing the bypass. The actuation to open the respective valve disk is carried out by supporting the other, closed valve.

From the WO 96/30635 An exhaust gas recirculation system is known in which independently opening valves are provided at the beginning of a radiator feed line and at the beginning of a bypass bypassing the radiator.

The DE 296 11 034 U1 discloses an arrangement for dissipating the heat loss of an internal combustion engine, in which two lines are opened or closed by a common rotationally actuated valve element. However, one line can not be opened independently of the other.

Finally, that describes DE 198 41 927 A1 means for recycling an exhaust gas flow, in which a cooler passage for cooling the recirculated exhaust gas and a bypass are controlled by respective flapper valves mounted on a common operating rod. For this reason, even in this case, one line can not be opened independently of the other and set in terms of their opening state.

Presentation of the invention

The invention has for its object to provide an exhaust gas recirculation system, in which in more effective Way, and with a simple construction of the entire valve assembly, a control of the exhaust gas temperature can be achieved by an optional flow through the radiator or the bypass.

The solution of this object is achieved by the exhaust gas recirculation system according to claim 1.

As a result, a radiator valve, which is for opening and closing the radiator supply, and a bypass valve, which is for opening and closing the bypass, are provided. According to the invention, the two valves on a common drive in the form of a rotatable in two directions rotary drive or a vacuum source. For such a rotary drive has been found that it can ensure the necessary opening and closing of the two valves particularly reliable and durable. This also applies to the particular embodiment in which the common drive is realized by a vacuum source. According to the invention there is the advantage that the structure of the valve assembly can be kept simple by using a common drive.

Furthermore, the valves are provided such that each of the two valves can be opened independently of the closed state of the other valve. In other words, the arrangement is such that, suitably, both lines can be closed, and further that one of the two lines can be opened while the other remains closed. As a result, in particular the mass flow through the radiator or the bypass is adjustable while the respective other element remains completely closed. This can be realized according to the invention on the one hand, that separate valve elements are provided for the radiator and the bypass valve, which are actuated by separate actuators, which are connected to the common drive, so that either the one or the other valve can be opened while the other remains unactuated. Furthermore, embodiments of the invention are provided, in which the radiator and the bypass valve are formed by a common valve element, which, as detailed below, can be designed such that one of the two valves is closed while the other is opened, and be Opening state is adjustable.

With regard to the drive of the exhaust gas recirculation system according to the invention, it should be mentioned that a motor with a suitable gear, a drive with a rotary magnet, a torque motor or a stepping motor can be provided as the rotary drive. Furthermore, over- or vacuum-controlled pneumatic actuators for realizing a rotary drive are conceivable. Finally, the common drive of the two valves can be realized by a vacuum source.

Preferred developments are described in the subclaims.

Preferably, the two valves are biased in their respective closed position, so that no exhaust gas recirculation takes place without actuation of the drive, which may be desirable in certain situations. Characterized in that the exhaust gas recirculation system according to the invention usually comprises separate actuation mechanisms, at least separate valve rods for the two valves, the respective component which applies the bias, usually a compression spring, particularly well adapted to the situation present in the respective valve.

A particularly compact design for the valve arrangement of the exhaust gas recirculation system according to the invention results when the valve rods of both valves are coaxial with each other. in this connection It is conceivable that the two valve rods extend from the common drive in opposite directions. However, it is preferred that the two coaxial valve rods are guided into each other, resulting in a particularly compact design in this embodiment.

The actuation of the two valves by a common drive in the form of a vacuum source can be particularly effective in that both valves have a membrane which delimits a vacuum chamber, which is connectable to the common vacuum source.

For the actuation of the two valves by means of a common, rotatable in two directions rotary drive, it is advantageous if the rotary drive has a rotary member or acts on this, which has a thread, and further an actuator is provided with a thread.

In this case, it is preferred that two rotary elements are provided which have a right- or a left-hand thread, wherein the actuating element of the one valve has a thread of one direction, and the actuating element of the other valve has a thread of the other direction. As a result, both actuators are actuated during the rotation of the rotary drive, wherein only one of the two actuators is moved in a direction to open the valve. The other actuator runs in a sense into the void.

Alternatively, a common rotary drive embodiment is preferred, in which a plurality of rotary elements are present, each having a cam. By the appropriate design of the directions of rotation of the rotary elements and the cams attached thereto can be realized that either the one or the other valve can be opened by means of the common drive.

It has finally been found in experiments to provide a common valve element for the radiator and the bypass valve, which selectively opens the radiator inlet or the bypass, and closes the other inlet or both lines. Such a common valve element can be moved particularly reliably by a rotary drive.

For the common valve element in particular a rotary valve or a rotatable disc with suitable recesses has proven to be favorable. For example, a rotary valve may be provided to extend along its circumference over the adjacent openings of the radiator passage and the bypass. Thus, one of the two openings can be partially or arbitrarily adjusted by turning the rotary valve, while the other opening remains closed. Alternatively, a disc may be provided with at least one recess which rotates about the disc axis. By displacing the recess due to the rotation of the disc such that the recess is wholly or partially aligned with one of the openings, the opening of the radiator or the bypass can be released while the other opening remains completely closed.

Brief description of the drawings

The invention will be explained in more detail with reference to embodiments shown by way of example in the drawings.

Fig. 1

eine Schnittansicht des erfindungsgemäßen Abgasrückführsystems in einer ersten Ausführungsform;

Fig. 2

eine Schnittansicht des erfindungsgemäßen Abgasrückführsystems in einer zweiten Ausführungsform;

Fig. 3

eine Schnittansicht des erfindungsgemäßen Abgasrückführsystems in einer dritten Ausführungsform;

Fig. 4

eine Draufsicht mit Teilschnitt des erfindungsgemäßen Abgasrückführsystems in einer vierten Ausführungsform;

Fig. 5

eine Seitenansicht eines erfindungsgemäßen Abgasrückführsystems in einer fünften Ausführungsform;

Fig. 6

eine Schnittansicht eines Abschnitts des in Fig. 5 gezeigten Abgasrückführsystems; und

Fig. 7

eine Schnittansicht des erfindungsgemäßen Abgasrückführsystems in einer sechsten Ausführungsform.

Show it:

Fig. 1

a sectional view of the exhaust gas recirculation system according to the invention in a first embodiment;

Fig. 2

a sectional view of the exhaust gas recirculation system according to the invention in a second embodiment;

Fig. 3

a sectional view of the exhaust gas recirculation system according to the invention in a third embodiment;

Fig. 4

a plan view with a partial section of the exhaust gas recirculation system according to the invention in a fourth embodiment;

Fig. 5

a side view of an exhaust gas recirculation system according to the invention in a fifth embodiment;

Fig. 6

a sectional view of a portion of in Fig. 5 shown exhaust gas recirculation system; and

Fig. 7

a sectional view of the exhaust gas recirculation system according to the invention in a sixth embodiment.

Detailed description of preferred embodiments of the invention

As in Fig. 1 can be seen, the exhaust gas recirculation system according to the invention has a section in which a radiator 10 and a bypass bypass 12 bypassing the radiator are provided. As indicated by the arrow A, the exhaust gas due to the air supply system of an internal combustion engine flows through either the radiator 10 or the bypass 12 depending on the position of the two valves 16 opening and closing the radiator inlet and 18 opening and closing the bypass At the in Fig. 1 illustrated embodiment, it is also possible that both flows are partially opened, so that the respective proportion of the exhaust gas can be controlled, which flows through the radiator 10 and the bypass 12. Thereby, the temperature of the exhaust gas can be adjusted depending on the running state of the engine.

The two valves 16, 18 each have a valve plate 20, 22, which cooperates with an associated valve seat for closing the respective inlet. In the case shown, the two valve rods 24, 26 are further designed such that the valve rod 24 of the cooler valve 16 is guided in the valve rod 26 of the bypass valve 18. With regard to the opening movement, it should be noted that the cooler valve 16 is opened by moving upward, while the bypass valve 18 is opened by a downward movement.

This respective movement is carried out according to the invention by a common drive against a respective compression spring 28, 30 which biases both valves in their closed imagination. For actuation by means of a vacuum source, the respective valve rods 24, 26 are connected at their upper ends to a respective membrane 32, 34, each defining a vacuum chamber 36, 38. By means of suitable connections 40, the vacuum chamber 36, 38 can each be connected to a vacuum source. As can be readily appreciated, the valve 16 is opened by the valve plate 20 is raised when a negative pressure is applied to the associated vacuum chamber 38. Likewise, the valve plate 22 of the bypass valve 18 moves downward, and the valve opens when a negative pressure is applied to the vacuum chamber 36. By suitable controls of each acting in the vacuum chamber 36, 38 pressure can also be realized the case that the two valves 16, 18 are opened independently.

At the in Fig. 2 illustrated embodiment, the valves 16, 18 as such, including the valve rods 24, 26 similar to the embodiment of the Fig. 1 designed. However, they are not provided at their respective upper area with a membrane, but only with a respective plate-like element 42, via which the force generated when opening the valve in the respective compression spring 28, 30 force is transmitted to the valve rod 24, 26. The actuation of the two valves takes place in this case via a rotary drive, which is provided in the case shown as a DC motor 44. The rotation of the DC motor 44 is transmitted to a gear 46 which has a thread on its hub, so that rotation of the gear 46 is transmitted to a translationally guided actuator. Depending on the direction of rotation of the gear 46, the actuator moves in one or the other direction and pushes up the valve rod 24 when moving upward, so that the radiator valve 16 opens. Likewise, when downwardly actuated by rotation of the gear 46 in the other direction, it pushes down the valve rod 26 so that the bypass valve 18 opens. The other valve remains unconfirmed. By means of this embodiment, a particularly compact design of the valve arrangement of the exhaust gas recirculation system according to the invention can be achieved by means of a common rotary drive 44.

At the in Fig. 3 In the embodiment shown, this principle of actuation of either one or the other valve by a common rotary drive, which rotates in different directions, also realized. The rotary drive is as in the embodiment of Fig. 2 from a DC motor 44, the rotation of which is transmitted to a gear 46. This in turn has a thread on its hub, so that the rotational movement is transmitted to a translationally guided actuator 48. When the gear rotates in such a way that the actuating element is pushed to the right, it releases itself from the valve rod 26 of the left-hand recognizable Bypass valve 18 and opens the right to be recognized cooling valve 16, so that the exhaust gas, as indicated by the arrow A, enters the radiator 10.

Similarly, the bypass valve 18 can be opened by rotation on the gear 46 is applied in a different direction, and the actuator 48 is pushed to the left accordingly. A compression spring 28 provides for closing the radiator valve 16 and remaining in the closed position. When the bypass valve 18 is to be opened, the actuating element 48 is displaced to the left by a suitable direction of rotation of the motor 44, and its end comes off from the left end of the valve rod 24 of the cooler valve 16 according to the figure. On the side of the bypass valve 18 is also a Compression spring 30 is provided to bias the valve in its closed position.

Also in the embodiment of Fig. 4 the optional opening and closing of the radiator valve 16 and the bypass valve 18 by a common rotary drive in the form of a DC motor 44. The rotation of the DC motor 44 is converted via gears in a sliding movement of actuators 48 and 50. In this case, one gear 46 has a right-hand thread 52, and the other gear 54 has a left-hand thread 56. As the rotary motor 44 rotates, the corresponding thread of one gear causes movement of the respective actuator 48, 50 in a direction to open the radiator 16 or by-pass valve 18 against the force of the compression spring 28, 30. The other actuator 50 moves each away from the associated valve, so that it runs into the void, and the non-open valve remains closed.

If opening of the other valve is intended, the motor is rotated in the other direction so that the actuator of the open valve moves away from it, the valve by the force of the compression spring in the closed position is returned, and the actuator is henceforth from the end of the valve stem out of contact. Upon continuation of the movement, the last considered actuator moves away from the valve, while the other actuator pushes the other valve against the force of the compression spring.

Also in the embodiment of the Fig. 5 Different directions of rotation of rotary elements for selectively opening and closing the two valves are used. In this case, the rotational movement of a motor 44 is ultimately transmitted to two intermeshing and therefore rotating in different directions gears 46 and 54. The gears each have a cam 58, 60 which cooperates with a respective lever 62 and 64. The lever is as complementary Fig. 6 showing, which represents the left portion of the arrangement in section, connected to a flap 66 which forms the radiator and bypass valve. If now (cf. Fig. 5 ), the motor 44 is rotated in such a way that the gear 46 rotates counterclockwise, the associated lever 62 is deflected to the left, and this deflection movement is transmitted through a perpendicular to the plane extending bar on the flap which on this rod is attached so that one of the two valves is opened.

At this time, because the two gears 46, 54 mesh with each other, the other gear 54 rotates in the clockwise direction so that the associated cam 60 also rotates in the clockwise direction and a portion of the cam is engaged with the jack 44 which has no actuating contour, ie no changing radial extent. Therefore, the lever 64 and the associated, other valve remains unactuated. In the same way, an actuation of the last considered valve is effected in that the rotary drive is rotated in the other direction, so that the gear 46 in the clockwise direction rotates, and due to the corresponding configuration of the cam 58, no actuation of the lever 62 takes place, but the meshing with the gear 46 gear 54 is rotated counterclockwise, so that the actuation contour of the cam 60 deflects the lift 64, and the flap of the other valve is opened.

In Fig. 7 Finally, an embodiment of the exhaust gas recirculation system according to the invention is shown, in which the radiator and the bypass valve have a common valve element, on the one hand, as in Fig. 7 can be seen, both inlets can close, so that no exhaust gas recirculation takes place. By turning the valve member 68 counterclockwise, so to speak upwards, the inlet of the radiator 10 is released, while by turning down the bypass 12 is opened. The actuation of the valve element 48 is carried out according to the invention by a rotary drive, which acts on a perpendicular to the plane extending actuating rod. This rotary drive can be provided due to the relatively slight angular movement as a stepper or so-called torque motor. Alternatively, it is conceivable to use a DC motor, and convert its rotational movement via a suitable gear in a smaller rotational movement to realize the required low deflection of the valve member 68. It should also be noted that the connection of the valve element 68 with the actuating rod 70 via a spring element 72 which presses the valve element 68 against the two valve seats. Furthermore, the valve element in the case shown is comparatively thin-walled, but it can also be made thicker, for example, from the solid.

As an alternative to the in Fig. 7 illustrated embodiment, that the front side of the radiator, in which both the opening of the radiator, and adjacent thereto, the opening of the bypass is located in essential plan can be designed. Covering the opening may be provided with a disc having at least one suitable recess which surrounds one (in accordance with FIG Fig. 7 ) is rotatable in the plane lying axis. By turning the disk, the recess is adjustably aligned with one of the openings so that either the radiator or the bypass is opened and the opening condition can be adjusted while the other opening remains fully closed.

Claims (9)

Exhaust gas recirculation system comprising a radiator (10), a bypass (12), a radiator valve (16) for opening and closing the radiator inlet and a bypass valve (18) for opening and closing the bypass (12)
characterized in that
the cooling valve (16) and the bypass valve (18) have a common drive in the form of a bidirectionally rotatable rotary drive (44) or a vacuum source, and in that each of the two valves (16, 18) is independent of the closing condition of the other valve (16 , 18) can be opened. Exhaust gas recirculation system according to claim 1, characterized in that the two valves (16, 18) are biased in the closed position. Exhaust gas recirculation system according to claim 1 or 2, characterized in that the valve rods (24, 26) of both valves (16, 18) concentric with each other and preferably are guided into each other. Exhaust gas recirculation system according to one of the preceding claims, characterized in that the two valves each have a membrane (32, 34) which defines a vacuum chamber (36, 38) which is connectable to a common vacuum source. Exhaust gas recirculation system according to one of claims 1 to 3, characterized in that the rotary drive (44) has at least one rotary element (56, 54) which is provided with a thread. Exhaust gas recirculation system according to claim 5, characterized in that two rotary elements (46, 54) are provided which have a right (52) and a left-hand thread (56). Exhaust gas recirculation system according to claim 5, characterized in that two rotary elements (46, 54) are provided, each having a cam (58, 60). Exhaust gas recirculation system according to one of the preceding claims, characterized in that the radiator valve (16) and the bypass valve (18) have a common valve element (68) which selectively closes the radiator inlet or the bypass (12) or both lines. Exhaust gas recirculation system according to one of the preceding claims, characterized in that the common valve element (68) is a rotary valve or a disc with at least one recess.

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