ES2351537T3 - 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

one

Technical scope

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

In the combustion engine sector, for the improvement of emission values and for the reduction of fuel consumption, the recirculation of the exhaust gases emitted by the engine to the air supply system of the engine has long been known combustion engine Since the temperature of the flue gases changes depending on the operating state of the engine, it is necessary to regulate the temperature of the exhaust gas so that it cools in particular in the hot state of the engine.

State of the art

From DE 199 06 401 an exhaust gas recirculation system according to the preamble of claim 1 is known and has a refrigerator that is traversed by the exhaust gas, a shunt that surrounds the refrigerator and a valve that alternately closes the inlet from the refrigerator or bypass. Therefore, depending on the operating state of the engine, it can be controlled whether the exhaust gas flows through the refrigerator and therefore cools, or if the refrigerator is surrounded, for example, in the cold operation phase, so that the Exhaust gas maintains its outlet temperature.

Document DE 197 33 964 A1 discloses an arrangement of valves for the control of a recirculated flow of exhaust gases, in which the two valve plates have a common operating mechanism for opening and closing the refrigerator inlet and for the opening and closing of the branch. The drive for opening the corresponding valve plate is carried out by support on the respective other closed valve.

From WO 96/303635, an exhaust gas recirculation system is known in which valves are present which open independently of each other at the beginning of a supply line to the refrigerator and at the beginning of a branch surrounding the refrigerator.

Document DE 296 11 034 U1 discloses an arrangement for the evacuation of lost heat from a combustion engine, in which two ducts are opened or closed by a common valve element rotatably actuated. However, one conduit cannot be opened independently of the other.

Finally, document DE 198 41 927 A1 describes a device for the recirculation of an exhaust gas flow, in which a passage of the refrigerator is controlled for cooling the recirculated exhaust gas and a bypass by means of butterfly valves that are mounted on a common drive bar. For this reason, in this case, the duct cannot be opened independently of the other and adjusted with respect to its opening state.

EP 0 489 263 A2 refers to an exhaust gas recirculation system with a refrigerator and a shunt, whose ducts can be closed each time by a valve that is connected in the form of the suction duct with a source of depression.

Description of the invention

The invention aims to create an exhaust gas recirculation system in which, effectively and with a simple structure of the entire valve arrangement, control of the temperature of the exhaust gases can be achieved by means of a stream of Alternative circulation of the refrigerator or bypass.

The solution of this objective is carried out by the exhaust gas recirculation system according to claim 1.

Accordingly, a refrigerator valve is provided, which serves to open and close the supply to the refrigerator, and a bypass valve, which serves to open and close the bypass. According to the invention, the two valves have a common drive in the form of a two-way rotary drive. For such a rotary drive it has been found that the necessary opening and closing of the two valves can be ensured in a particularly safe and durable way. According to the invention, the advantage is that the structure of the valve arrangement can be easily maintained by using a common rotary drive.

According to the invention, a common valve element is provided for the refrigerator valve and the bypass valve, which alternatively opens the supply to the refrigerator or the bypass, and closes respectively the other inlet or also the two ducts. A similar common valve element can be moved by a particularly safe rotary drive.

In addition, the valves are provided so that each of the two valves can be opened independently of the closing state of the other valve. In other words, the arrangement is provided so that both ducts can be closed properly, and in such a way that one of the two ducts can be opened while the other remains closed. Therefore, in particular, the flow rate can be adjusted through the refrigerator or bypass, while the respective other element remains completely closed.

The cooling valve and the bypass valve are formed as a common valve element which, as set forth below in detail, can be configured so that one of the two valves is closed while the other is opened, and can adjust its opening state.

With regard to the operation of the exhaust gas recirculation system according to the invention, it is mentioned that as an electric rotary drive an electric motor with an appropriate transmission, a drive with a rotating magnet, a torque motor, a stepper motor or a motor is provided. DC motor

Advantageous variants are described in the dependent claims.

Preferably, the two valves are prestressed in their corresponding closed position, so that without recirculation of the drive there is no recirculation of the exhaust gases which may be desired in certain situations.

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

In this case it is preferred that two rotating elements having a thread on the right or a thread on the left are provided, the actuating element of a valve having a thread in one direction, and the actuating element of the other valve a thread In the other direction. Therefore, during the rotation of the rotary drive, the two drive elements are actuated, only one of the two drive elements moving in one direction for the opening of the valve. The other drive element works so to speak in a vacuum.

Alternatively, an embodiment with a common rotary drive is preferred, in which several rotating elements having a cam respectively are present. By means of the appropriate configuration of the directions of rotation of the rotating elements, as well as of the cams mounted here it can be achieved that by means of the common actuation one or the other valve can be opened alternately.

For the common valve element, a rotary slide or a rotary disc with appropriate notches has proven to be suitable in particular. A rotary slide can be provided, for example, so that it extends along its contour over adjacent openings of the refrigerator passage and the bypass. Therefore, by rotating the rotary slide, one of the two openings can be partially or freely released while the other opening remains closed. Alternatively, a disc with at least one notch that rotates about the axis of the disc can be provided. By displacing the notch due to the rotation of the disc, such that the notch aligns totally or partially with one of the openings, the opening of the refrigerator or the bypass can be released, while the other opening remains completely closed.

Brief description of the drawings

The invention will now be explained in detail by means of the embodiments shown by way of example in the drawings. They show:

Fig. 1

a sectional view of the exhaust gas recirculation system in

a first unclaimed embodiment;

Fig 2

a sectional view of the exhaust gas recirculation system in

a second unclaimed embodiment;

Fig. 3

a sectional view of the exhaust gas recirculation system in

a third unclaimed embodiment;

Fig. 4

a plan view with partial section of the recirculation system of

exhaust gases in a fourth unclaimed embodiment;

Fig. 5

a side view of an exhaust gas recirculation system in a

fifth unclaimed embodiment;

Fig. 6

a sectional view of a part of the gas recirculation system of

exhaust shown in fig. 5; Y

Fig. 7

a sectional view of the exhaust gas recirculation system in

a sixth embodiment according to the invention.

Detailed description of preferred embodiments of the invention

As can be seen in fig. 1, the exhaust gas recirculation system has a section in which a refrigerator 10 and a branch 12 surrounding the refrigerator are provided. As indicated by arrow A, the exhaust gas to be recirculated to the air supply system of a combustion engine, according to the position of the two valves, the 16 that opens and closes the inlet of the refrigerator and the 18 that opens and close the bypass, go through the refrigerator 10 or bypass 12. In the embodiment shown in fig. 1, it is also possible that both passages are partially opened in such a way that the corresponding fraction of the exhaust gas passing through the refrigerator 10 and the bypass 12 can be adjusted. In this way the temperature of the exhaust gas can be adjusted according to the state of engine operation

The two valves 16, 18 respectively have a valve plate 20, 22 that cooperates with a corresponding valve seat for closing the corresponding inlet. In addition, in the case shown, the two valve bars 24, 26 are configured such that the valve bar 24 of the refrigerator valve 16 is guided in the valve bar 26 of the bypass valve 18. Regarding the movement of opening should be mentioned that the refrigerator valve 16 is opened by the upward movement, while the bypass valve 18 is opened by a downward movement.

This corresponding movement is performed by a common drive against a corresponding compression spring 28, 30 which pretends the two valves in their previous closed position. For actuation by means of a vacuum source, the corresponding valve bars 24, 26 are joined at their upper ends with a corresponding membrane 32, 34 which respectively defines a depression chamber 36, 38. Through appropriate connections 40 the depression chamber 36, 38 respectively with a vacuum source. As can be seen without the slightest difficulty, the valve 16 opens up the valve plate 20, if a depression is applied on the corresponding depression chamber 38. Likewise, the valve plate 22 of the bypass valve 18 moves downwards, and the valve opens if a depression is applied to the depression chamber 36. By means of appropriate controls of the pressure that acts each time in the depression chamber 36, 38, it can also be the case that the two valves 16, 18 open independently of one another.

In the embodiment shown in fig. 2, the valves 16, 18 are configured as such inclusive or valve stems 24, 26 similarly to the embodiment of fig. 1. However, in their corresponding upper area they are not provided with a membrane, but only with a corresponding element 42 of the plate type, whereby the force generated by opening the valve in the corresponding compression spring 28, 30 is transmitted to the valve stem 24, 26. The two valves are operated in this case by means of a rotary drive which is provided in the case shown as a direct current motor

44. The rotation of the direct current motor 44 is transmitted to a cogwheel 46 which has a thread in its hub, such that a rotation of the cogwheel 46 is transmitted to a translatory guided drive element. According to the direction of rotation of the gearwheel 46, the drive element moves in one or the other direction and in the upward movement presses the valve bar 24 upward so that it opens the refrigerator valve 16. From the in the same way, when driving downwards, press the valve bar 26 downwards by turning the gearwheel 46 in the other direction, so that it opens the bypass valve 18. The respective other valve remains not actuated. By means of this configuration, a particularly compact constructive form of the arrangement of the valves of the exhaust gas recirculation system can be achieved by a common rotary drive 44.

In the embodiment shown in fig. 3, this principle of a discretionary drive of one or the other valve is also realized by a common rotary drive that rotates in different directions. The rotary drive is composed, according to the embodiment of fig. 2, of a direct current motor 44 whose rotation is transmitted to a cogwheel 46. This in turn has a thread in its hub, so that the rotation movement is transmitted to a drive element 48 guided in a translatory manner. If the sprocket rotates in such a way that the drive element moves to the right, then it separates from the valve stem 26 of the bypass valve 18 which can be seen on the left and opens the refrigerator valve 16 which must be appreciated. on the right, so that the exhaust gas, as indicated by arrow A, reaches the refrigerator 10.

In the same way, the bypass valve 18 can be opened, applying a rotation in the other direction on the gearwheel 46, and the actuating element 48 moves correspondingly to the left. A compression spring 28 deals with the closure of the fan valve 16 and remains in the closed position. If the bypass valve 18 must be opened, the actuating element 48 moves to the left by an appropriate direction of rotation of the motor 44, and its end is separated from the left end according to the figure of the valve stem 24 of the valve of the refrigerator 16. On the side of the bypass valve 18 a compression spring 30 is also provided to prestress the valve in its closed position.

Also in the embodiment of fig. 4 the alternative opening and closing of the refrigerator valve 16 and the bypass valve 18 is carried out by means of a common rotary drive in the form of a direct current motor 44. The rotation of the direct current motor 44 is converted through gearwheels in a displacement movement of the drive elements 48 and 50. In this case the one gearwheel 46 has a thread on the right 52, and the other gearwheel 54 a thread on the left 56. If the motor rotates rotation 44, the corresponding thread of the toothed wheel causes a movement of the corresponding drive element 48, 50 in a direction for opening the valve of the refrigerator 16 or the valve of the bypass 18 against the force of the compression springs 28, 30. The other actuating element 50 exits respectively from the corresponding valve, such that it operates in a vacuum, and the valve that must not be opened remains closed. ada.

If an opening of the other valve is intended, the motor is rotated in the other direction, so that the actuator of the open valve leaves it, the valve is brought back to the closed position by the force of the springs compression, and the actuator stops contacting hereinafter with the end of the valve stem. When the movement continues, the last observed drive element is removed from the valve, while the other drive element presses the other valve against the force of the compression springs.

Also in the embodiment of fig. 5 different directions of rotation of the rotating elements are used for the discretionary opening and closing of the two valves. In this case, the rotational movement of a motor 44 of the last end is transmitted on two sprockets 46 and 54 that engage with each other and rotate in this direction in different directions. The sprockets respectively have a cam 58, 60 that cooperates with a corresponding connecting rod 62 and 64. The corresponding connecting rod is attached, as shown in a complementary way to fig. 6 which represents in section the left part of the arrangement, with a cover 66 that forms the refrigerator valve and the bypass valve. If now (compare fig. 5) the engine 44 is rotated in such a way that the sprocket 46 rotates counterclockwise, the assigned connecting rod 62 deflects to the left, and this diverting movement is transmitted by a spindle that extends perpendicular to the drawing plane on that cover that is mounted on this bar, so that one of the two valves is opened.

At this time it rotates, since the two sprockets 46, 54 engage each other, the other sprocket 54 in the direction of the clockwise direction, so that the corresponding cam 60 also rotates in the direction of the clockwise direction and an area of the Cam is in contact with connecting rod 64 which does not have a drive contour, that is, a radial extension that changes. Therefore, the lever 64 and the other corresponding valve remain in a non-actuated manner. In the same way an actuation of the last valve observed is carried out, in such a way that the gearwheel 46 rotates clockwise, and due to the corresponding configuration of the cam 58, an actuation of the connecting rod 62 is not performed, however , the sprocket 54 that engages with the sprocket 46 rotates counterclockwise, so that the cam contour 60 deflects the lever 64, and the cover of the other valve opens.

In fig. 7 an embodiment of the exhaust gas recirculation system according to the invention is finally shown, in which the refrigerator valve and the bypass valve have a common valve element that, on the one hand, can close the two inlets as can be seen in fig. 7, such that a recirculation of the exhaust gases is not performed. By rotating the valve element 68 counterclockwise, thus in a certain way upwards, the inlet of the refrigerator 10 is released, while by the downward rotation the bypass 12 is opened. The actuation of the valve element 48 is carried out according to the invention by a rotary drive acting on a drive rod that extends perpendicularly to the drawing plane. This rotary drive can be provided due to the comparatively reduced angular movement as a stepper motor or so-called torque motor. Alternatively, the use of a direct current motor can be conceived, and the conversion of its rotary movement through an appropriate transmission into a smaller rotary movement for the realization of the small necessary deviation of the valve element 68. It should still be mentioned that the union of the valve element 68 with the actuating rod 70 is realized through a spring element 72 that presses the valve element 68 against the two valve seats. In addition, the valve element has

a comparablely thin wall in the case shown, however, can also be made thicker, for example, from a block. As an alternative to the embodiment shown in fig. 7 is to emphasize that the front face of the refrigerator, in which the refrigerator opening is located, as well as

5 also adjacent to it, the branch opening, can be configured essentially flat. Covering the opening can be provided with a disc with at least one appropriate notch that can rotate around an axis that is in the plane of the drawing (according to fig. 7). By rotating the disc, the notch is aligned in an adjustable way with one of the openings, so that the refrigerator or bypass can be opened, and can

10 adjust the opening state while the other opening remains completely closed.

Claims (6)

1.-Exhaust gas recirculation system with a refrigerator (10), a bypass (12), a refrigerator valve (16) for opening and closing the supply to the refrigerator and a bypass valve (18) for the opening and closing the bypass (12), presenting the refrigerator valve (16) and the bypass valve (18) a common actuation and being able to open each of the two valves (16, 18) independently of the state of closing of the other valve (16, 18), characterized in that the drive is configured as a rotary drive (44) that can rotate in two directions, that is, as an electric motor with an appropriate transmission, a drive with a rotating magnet, a torque motor, a stepper motor or a direct current motor, and because the refrigerator valve (16) and the bypass valve (18) have a common valve element (68) that discretionary closes the supply to the refri gerador or the shunt (12) or the two ducts. 2. Exhaust gas recirculation system according to claim 1, characterized in that the two valves (16, 18) are prestressed in the closed position. 3. Exhaust gas recirculation system according to claim 1 or 2, characterized in that the rotary drive (44) has at least one rotating element (56, 54) which is provided with a thread. 4. Exhaust gas recirculation system according to claim 3, characterized in that two rotating elements (46, 54) having a right hand thread are provided. (52) or a thread to the left (56). 5. Exhaust gas recirculation system according to claim 3, characterized in that two rotating elements (46, 54) are provided, respectively having a cam (58, 60). 6. Exhaust gas recirculation system according to one of the preceding claims, characterized in that the common valve element (68) is a rotary slide or a disc with at least one notch.