EP1275838A1 - Exhaust 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 field

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

To improve emissions and reduce emissions It is in the field of fuel economy Internal combustion engines have long been known by the engine emitted exhaust gas in the air supply system of the Internal combustion engine attributed. Since the temperature of the Exhaust gases depending on the operating state of the engine changed, it is necessary to adjust the temperature of the exhaust gas to regulate in such a way that this is particularly in the warm Condition of the engine is cooled.

State of the art

An exhaust gas recirculation system according to the preamble of claim 1 is known from DE 199 06 401 of the applicant and has a cooler through which the exhaust gas flows, a bypass which bypasses the cooler, and a valve that optionally selects the Radiator inlet or bypass closes. This can ever can be controlled according to the operating state of the engine, whether that Exhaust gas flows through the cooler and is therefore cooled or whether the cooler, for example in the cold running phase of the Motors, is bypassed so that the exhaust gas its Maintains initial temperature.

DE 197 33 964 A1 discloses a valve arrangement for Control of a recirculated exhaust gas flow in which the two valve plates for opening and closing the Radiator inlet and for opening and closing the bypass have a common actuation mechanism. The Actuation to open the respective valve plate takes place by supporting the other, closed valve.

An exhaust gas recirculation system is known from WO 96/30635, at the independently opening valves at the beginning of a Cooler supply line and provided at the beginning of a bypass are bypassing the cooler.

DE 296 11 034 U1 discloses an arrangement for removal the heat loss of an internal combustion engine in which two Lines through a common rotary valve element be opened or closed. However, it cannot be one Line can be opened independently of the other.

Finally, DE 198 41 927 A1 describes a device for recycling an exhaust gas flow, in which a Cooler passage for cooling the recirculated exhaust gas and a Bypass can be controlled by respective flap valves that are attached to a common operating rod. Out for this reason, even in this case, one line cannot opened independently of the other and regarding her Opening state can be set.

Presentation of the invention

The invention is based on the object To create exhaust gas recirculation system in which in more effective Way and with a simple construction of the whole Valve arrangement a control of the exhaust gas temperature by a optional flow through the cooler or the bypass can be achieved.

This problem is solved by the Exhaust gas recirculation system according to claim 1.

Accordingly, a radiator valve that is open and Serves to close the cooler supply, and a bypass valve, that serves to open and close the bypass. According to the invention, the two valves have a common one Drive in the form of a rotatable in two directions Rotary actuator or a vacuum source. For one such rotary drive has been found to be the required opening is particularly reliable and permanent and ensure closing of the two valves. This also applies to the special 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 arrangement by using a common drive can be kept simple.

Furthermore, the valves are provided such that each of the two valves regardless of the closed state of the other Valve can be opened. In other words, it is Arrangement provided such that both suitably Lines can be closed, and that further a of the two lines can be opened while the other remains closed. This is particularly the Volume flow through the cooler or the bypass adjustable while the other element is completely remains closed. According to the invention, this can on the one hand can be realized that for the cooler and Bypass valve separate valve elements are provided that can be operated by separate actuators that with are connected to the common drive, so that either one or the other valve can be opened while the other remains unactuated. Furthermore, are according to the invention Embodiments provided in which the cooler and Bypass valve formed by a common valve element that, as detailed below, can be designed so that one of the two valves is closed and the other is opened Opening state is adjustable.

With regard to the drive of the invention Exhaust gas recirculation system should be mentioned that as a rotary drive Electric motor with a suitable gear, a drive with a rotary magnet, a torque motor or a stepper motor can be provided. Furthermore, are over or vacuum-controlled pneumatic drives for implementation of a rotary drive conceivable. Finally, the common The two valves are driven by a vacuum source become.

Preferred further developments are in the subclaims described.

The two valves are preferably in their respective biased closed position so that without actuation of the drive, there is no exhaust gas recirculation, which in certain situations may be desired. By that Exhaust gas recirculation system according to the invention in this Embodiment usually separate Actuating mechanisms, at least separate valve rods for The two valves, the respective component that applies the preload, usually a compression spring, particularly good at that of the respective valve Situation to be adjusted.

A particularly compact design for the valve arrangement of the Exhaust gas recirculation system according to the invention results if the Valve rods of both valves are coaxial with each other. in this connection it is conceivable that the two valve rods differ from the extend common drive in opposite directions. However, it is preferred that the two be coaxial Valve rods are guided into each other, which is in this Embodiment results in a particularly compact design.

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

For the actuation of the two valves by means of a It is a common rotary drive that can be rotated in two directions advantageous if the rotary drive has a rotary element or acts on it, which has a thread, and further an actuator with a thread is present.

It is preferred that two rotary elements are provided are that have a right-hand or left-hand thread, where the actuator of a valve is a thread of one direction, and the actuator of the other Valve has a thread in the other direction. hereby become both when the rotary drive rotates Actuators operated, only one of the two Actuators in one direction to open the valve is moved. The other actuator is running in a sense into the void.

Alternatively, an embodiment with common Rotary drive preferred, in which several rotary elements are present are, each having a cam. By the appropriate Design of the directions of rotation of the rotating elements and the cams attached to it can be realized that either one or the other valve using the common drive can be opened.

It has finally proven to be beneficial in trials highlighted a common valve element for the cooler and to provide the bypass valve, which optionally the Radiator supply or the bypass opens, and each closes another inlet or both lines. On such a common valve element can by a Rotary drive can be moved particularly reliably.

For the common valve element, in particular Rotary vane or a rotating disc with suitable Cutouts proved to be cheap. A rotary valve can for example, be provided so that it runs along its circumference over the adjacent openings of the Radiator passage and the bypass extends. Thus through Turn the rotary valve one of the two openings partially or freely adjustable, while the other opening remains closed. alternative can be provided a disc with at least one recess that rotates around the disc axis. By Moving the recess due to the rotation of the disc such that the recess is wholly or partially with one of the Openings is aligned, the opening of the radiator or the bypass are released while the other The opening remains completely closed.

Brief description of the drawings

In the following, the invention is illustrated by way of example in FIGS Drawings illustrated embodiments explained in more detail.

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 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 the exhaust gas recirculation system shown in Fig. 5; 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 can be seen in Fig. 1, the inventive Exhaust gas recirculation system a section in which a cooler 10 and a bypass 12 bypassing the cooler is provided. How is indicated by the arrow A, flows through to the Air supply system of an internal combustion engine to be recycled Exhaust gas depending on the position of the two valves 16, the Radiator inlet opens and closes, and 18 that bypass opens and closes either the cooler 10 or the bypass 12. In the embodiment shown in Fig. 1 it is furthermore possible that both flows partially be opened so that the respective proportion of the exhaust gas The cooler 10 and the bypass 12 can be regulated flows through. As a result, the temperature of the exhaust gas in Dependent on the running condition of the engine become.

The two valves 16, 18 each have a valve plate 20, 22 on that with an associated valve seat for Closing the respective inlet cooperates. By doing The case shown is also the two valve rods 24, 26 executed such that the valve rod 24 of the radiator 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 Radiator valve 16 is opened by moving upwards, during the bypass valve 18 by a downward movement is opened.

According to the invention, this respective movement is carried out by a common drive against a respective compression spring 28, 30, that biases both valves into their closed imagination. For the actuation by means of a vacuum source are the respective valve rods 24, 26 at their upper ends a respective membrane 32, 34 connected, each one Vacuum chamber 36, 38 defined. Via suitable connections 40 is the vacuum chamber 36, 38 each with a Vacuum source connectable. As can be easily seen, valve 16 is opened by valve plate 20 is raised when the associated vacuum chamber 38 a vacuum is applied. The same moves Valve plate 22 of the bypass valve 18 down, and that Valve opens when the vacuum chamber 36 is on Vacuum is applied. By suitable controls of the pressure acting in each case in the vacuum chamber 36, 38 also the case can be realized that the two valves 16, 18 can be opened independently.

In the embodiment shown in Fig. 2, the Valves 16, 18 as such including the valve rods 24, 26 designed similar to the embodiment of FIG. 1. However, they are not at their respective upper area a membrane, but only with a respective one plate-like element 42 provided, via which when opening of the valve in the respective compression spring 28, 30 generated Force is transmitted to the valve rod 24, 26. The In this case, the two valves are actuated via a rotary drive, which in the case shown as DC motor 44 is provided. The rotation of the DC motor 44 is transmitted to a gear 46, the has a thread on its hub so that rotation of the Gear 46 on a translationally guided Actuator is transferred. Depending on the direction of rotation of the gear 46, the actuating element moves into the one direction or another and pushes up when moving the valve rod 24 upwards so that the radiator valve 16 opens. In the same way it presses down when actuated by rotating the gear 46 in the other direction Valve rod 26 down, so that the bypass valve 18th opens. The other valve remains inactive. By this configuration can be based on a common Rotary drive 44 a particularly compact design Valve arrangement of the exhaust gas recirculation system according to the invention can be achieved.

In the embodiment shown in Fig. 3, this is Principle of operating either one or the other Valve by a common rotary drive, which is in turns different directions, also realized. As in the embodiment of FIG. 2 from a DC motor 44, the rotation of which on Gear 46 is transmitted. This in turn points to his Hub thread on, so the twisting motion on one Transfer translationally guided actuator 48 becomes. If the gear rotates so that the Actuator is pushed to the right, so it releases from the valve rod 26 of the left to be seen Bypass valve 18 and opens what can be seen on the right Radiator valve 16 so that the exhaust gas, as indicated by arrow A is indicated, enters the cooler 10.

The bypass valve 18 can be opened in the same way, by turning the gear 46 in a different direction is applied, and the actuator 48 accordingly is pushed to the left. A compression spring 28 ensures that Closing the radiator valve 16 and remaining in the closed position. When the bypass valve 18 opens should be, the actuator 48 by suitable Direction of rotation of the motor 44 shifted to the left, and its The end separates from the left end according to the figure Valve rod 24 of the radiator valve 16. On the side of the Bypass valve 18 a compression spring 30 is also provided, to bias the valve into its closed position.

This is also done optionally in the embodiment of FIG. 4 Opening and closing 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 shifted by gears in a Actuators 48 and 50 converted. Here, the one gear 46 a right hand thread 52, and the other gear 54 a left hand thread 56. When the rotating motor 44 rotates, causes the corresponding thread of a gear Movement of the respective actuating element 48, 50 in one Direction to open radiator 16 or bypass valve 18 against the force of the compression spring 28, 30. The other Actuator 50 moves from the associated one Valve gone so that it doesn't work, and not too opening valve remains closed.

If it is intended to open the other valve, the motor rotates in the other direction so that the actuator of the open valve from this moved the valve by the force of the compression spring into the closed position is brought back, and that Actuator from now on except from the end of the valve stem Is touch. As the movement continues, this removes last viewed actuator from the valve, while the other actuator against the other valve the force presses on the compression spring.

Also in the embodiment of FIG. 5 different directions of rotation of rotating elements optional opening and closing of the two valves used. In this case, the rotation of a motor 44 will be last In the end two intermeshing and therefore in gears 46 and 54 rotating in different directions transfer. The gears each have a cam 58, 60 on, which cooperates with a respective lever 62 and 64. The respective lever is, as can additionally be seen from FIG. 6, which represents the left section of the arrangement in section, connected to a flap 66 which the cooler and Bypass valve forms. If now (see FIG. 5) the motor 44 is rotated such that the gear 46 rotates counterclockwise, the associated lever 62 deflected to the left, and this deflection movement is through a rod extending perpendicular to the plane of the drawing transmit the flap attached to this rod is so that one of the two valves is opened.

At this time, because the two gears 46, 54 comb with each other, the other gear 54 in the direction of Clockwise, so that the associated cam 60 also turns clockwise and on Area of the cam is engaged with the lift 44 which no actuation contour, i.e. no changing radial Extends. Therefore, the lever remains 64 and that associated other valve not actuated. In the same way the last valve viewed is actuated in that the rotary actuator is rotated in the other direction so that the gear 46 turns clockwise rotates, and due to the corresponding design of the cam 58 there is no actuation of the lever 62, but that with the Gear 46 meshing gear 54 counterclockwise is rotated so that the actuating contour of the cam 60 deflects the lift 64 and the flap of the other valve is opened.

7 is an embodiment of the Exhaust gas recirculation system according to the invention shown, in which the Radiator and the bypass valve a common valve element which, on the one hand, as can be seen in FIG. 7, can close both inlets so that none Exhaust gas recirculation takes place. By turning the valve element 68 counterclockwise, so to some extent upwards, the inlet of the cooler 10 is released while through Twisting down the bypass 12 is opened. The Actuation of the valve element 48 takes place according to the invention by a rotary drive that is perpendicular to the Actuating rod extending in the drawing plane acts. This Rotary drive can be due to the comparatively minor Angular movement as a step or so-called torque motor be provided. Alternatively, it is conceivable to use one DC motor to use, and its rotary motion over a suitable gearbox in a smaller rotary motion Realization of the required, small deflection of the Convert valve element 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 the valve element 68 presses against the two valve seats. Furthermore, the valve element is in the case shown comparatively thin-walled, but it can also be thicker, for example, be made from solid.

As an alternative to that shown in FIG. 7 Embodiment it should be noted that the end face of the Radiator, at which both the opening of the radiator, and also, adjacent to it, the opening of the bypass is located in the essential plan can be designed. The opening A pane can be covered with at least one suitable one Recess can be provided, which by a (according to FIG. 7) in the Axis lying in the drawing plane is rotatable. By twisting the Slice the recess in an adjustable manner aligned with one of the openings so that either the Radiator or the bypass opened, and the opening condition can be adjusted while opening the other remains completely closed.

Claims (9)

Exhaust gas recirculation system with a cooler (10), a bypass (12), a cooler valve (16) for opening and closing the cooler supply and a bypass valve (18) for opening and closing the bypass (12)
characterized in that
the cooler valve (16) and the bypass valve (18) have a common drive in the form of a rotary drive (44) which can be rotated in two directions or a vacuum source, and that each of the two valves (16, 18) is independent of the closed state 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 into 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) are guided concentrically to one another and preferably into one another. 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 can be connected 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-hand (52) or 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 cooler valve (16) and the bypass valve (18) have a common valve element (68) which either closes the cooler supply 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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