EP1707790A1 - Exhaust gas recirculation system - Google Patents

Abstract

The system has an exhaust gas recirculation valve with a single valve unit (10) that closes an exhaust gas recirculation line. A by-pass valve (12) is separated from the recirculation valve and closes a cool line and/or a by-pass line. The recirculation valve and the by-pass valve are arranged in a common valve housing (18). A lid axle of the by-pass valve is supported in a pivot axle of the recirculation valve. The lid axle and the pivot axle have a common axle center point.

Description

Technical area

The invention relates to an exhaust gas recirculation system.

In the field of internal combustion engines, it is known to recirculate exhaust gas to the fresh air side depending on the operating state, thereby reducing fuel consumption and pollutant emissions. In this context, the exhaust gas may further, depending on the operating state, at least partially passed through an exhaust gas cooler to adjust the temperature of the recirculated exhaust gas targeted.

State of the art

From the DE 699 12 335 T2 an exhaust gas heat exchanger device is known in which by means of a flap, the proportion of the guided through an exhaust gas cooler exhaust gas is adjustable. However, the exhaust gas recirculation line is not completely closed.

The EP 1 273 786 A2 relates to a switching device for exhaust gas recirculation in an internal combustion engine, with which the exhaust gas can be passed from an exhaust pipe either in an exhaust gas cooler and in a bypass line. In this case, the size of the passage opening is changeable overall by an additional control element. However, the switching element and the control element arranged therein must be made comparatively complex in order to ensure the required tightness can.

Presentation of the invention

The invention is based on the object to provide an efficient and simply constructed and manufactured exhaust gas recirculation system.

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

Consequently, the exhaust gas recirculation system as the core of an actuator, which simultaneously and independently of each other allows the volume and temperature control of the recirculated exhaust gas. This actuator consists on the one hand of an exhaust gas recirculation valve, which is provided with a single valve element with which an exhaust gas recirculation line is closed. In contrast to the above-mentioned prior art can thus be completely closed by means of a single valve element, an exhaust gas recirculation line, or the amount of recirculated exhaust gas are regulated as such by a single valve element. The fact that this can be realized with a valve element, the design of this exhaust gas recirculation valve is particularly simple. Namely, only the support surface of a single moving part, namely the valve element, must be suitably "sealable". In contrast, in the prior art has the disadvantage that the surfaces between two moving components are to make sufficiently sealed.

On the other hand, separated from the exhaust gas recirculation valve, a bypass valve is provided, with which a cooling and / or a bypass line can be closed. In principle, therefore, a second valve, namely the bypass valve, is present in the exhaust gas recirculation system according to the invention. However, this is separated from the exhaust gas recirculation valve, with which the exhaust gas recirculation line is closed as such. In other words These two valves do not work together. Rather, the exhaust gas recirculation valve alone closes the exhaust gas recirculation line and regulates, as mentioned, the amount of recirculated exhaust gas as such. The bypass valve regulates the desired exhaust gas temperature by closing the bypass valve with a cooling line leading through an exhaust gas cooler and / or a bypass line. Further, any intermediate positions are conceivable, so that a desired mixture between cooled exhaust gas and exhaust gas, which has been passed to the radiator through the bypass line, is conceivable.

According to the exhaust gas recirculation valve and the bypass valve are still arranged in a common valve housing. The fact that a single, common housing can be used for the two valves, there is a significant cost advantage. For example, the housing may be designed as a casting, and the use of a single, common housing requires only a single casting. By integrating into a common housing, a reduction of the installation space is also possible. Furthermore, there are advantages in that connecting pipes, seals and flanges, which are required in several valve housings, can be reduced in an economically advantageous manner. Thus, an exhaust gas recirculation system can be provided in a cost effective manner, in which both the amount of recirculated exhaust gas as such, and its temperature can be adjusted in the desired manner independently.

The inventive arrangement of the exhaust gas recirculation and bypass valve is suitable for both largely rectilinear and for U-shaped radiator. An embodiment with a straight-flow radiator is described below as a preferred embodiment with reference to the drawings. However, an embodiment with a U-shaped radiator is at this point too mention that such a cooler, for reasons of space, for example, "hanging" between the two legs, in other words the cylinder banks, a V-engine can be arranged. In such a case, the bypass valve, which may be designed as a flap, facing in the direction of that line through which the hot exhaust gas is supplied. Depending on the position of the bypass valve, the hot exhaust gas, for example deflected by the bypass valve, flows through the radiator or, at a position of the bypass valve in which the exhaust gas flow is not diverted into the radiator, passes into the exhaust gas recirculation line essentially completely and uncooled , At the beginning of the exhaust gas recirculation line can be arranged in this case, an exhaust gas recirculation valve. It is to be noted in such an embodiment that the bypass passage may be greatly shortened, and in particular may be formed only by the flow path defined by the common valve body of the bypass and exhaust gas recirculation valves. Even in such a case, the exhaust gas recirculation system according to the invention allows a simple structure and also allows the simultaneous and independent quantity and temperature control of the recirculated exhaust gas.

Preferred developments can be found in the further claims.

For the arrangement of the two independent valves, the exhaust gas recirculation valve and the bypass valve, there are basically a variety of possibilities. However, it has proven to be advantageous to arrange the exhaust gas recirculation valve and the bypass valve offset in the flow direction to each other. In this case, in particular, the bypass valve can be arranged upstream of the exhaust gas recirculation valve. Thus, the recirculated exhaust gas flows first, depending on the setting of the bypass valve, through the cooling and / or bypass line, mixes when flowing from the two lines, where Usually the bypass valve is located, to a recirculated exhaust gas of the desired temperature, and subsequently flows through the exhaust gas recirculation valve, with which the amount of recirculated exhaust gas is regulated.

For the construction of the two valves in detail is currently preferred, the exhaust gas recirculation valve and / or the bypass valve pivot or fold form. Although at least one of the two valves can also be configured as a translationally movable valve, the combination of the two valves in a single valve housing can be realized in a particularly simple manner if at least one, preferably both valves are pivotable or foldable.

Here, it offers particular advantages for a compact design, when both valves are pivotable or hinged, and the pivot or folding axes have a common axis or shaft center. In other words, the two axes are aligned with each other, so that the overall space requirement is particularly low.

In this case, an efficient and reliable storage of both valves can be achieved in that the folding axis of the bypass valve is mounted in the pivot axis of the exhaust gas recirculation valve. The reverse configuration, ie a bearing of the pivot axis of the exhaust gas recirculation valve in the folding axis of the bypass valve is of course also conceivable.

For the space-saving combination of the two valves together, in a common valve housing, a design has proven to be favorable, in which the exhaust gas recirculation valve is connected via at least one leg with its pivot axis, and the bypass valve is located adjacent to at least one such leg. The bypass valve is thus in a particularly space-saving manner in addition to the leg described pivot.

In particular, a design is currently preferred in which the exhaust gas recirculation valve is connected by two legs with its pivot axis, and the bypass valve between the two legs is hindurchschwenkbar. As a result, the two desired valve functions can be realized in a confined space.

For the integration of the two valves, the exhaust gas recirculation valve and the bypass valve, in a single valve housing, it has proved to be advantageous if the valve housing forms an angle between a direction of the cooling and / or bypass line and a direction of the exhaust gas recirculation line. Preferably, this angle is about 90 °. In a straight-flow radiator, the angle between the exhaust gas recirculation line and both the cooling and the bypass line may be present. In the embodiment described above with a U-shaped radiator, the angle is preferably present between the exhaust gas recirculation line and only the cooling line, while the (greatly shortened) bypass line extending through the valve housing can be aligned with the adjoining exhaust gas recirculation line.

Advantageously, the common valve housing may further comprise at least one recess in which the valve element of the exhaust gas recirculation valve, at least partially accommodated, at least in the fully open position. This advantageously ensures the least possible disruption of the flow in the valve housing.

Brief description of the drawings

• Fig. 1 in einer perspektivischen Schnittdarstellung einen Teil des erfindungsgemäßen Abgasrückführsystems;
• Fig. 2 in einer seitlichen Schnittdarstellung den in Fig. 1 gezeigten Teil des erfindungsgemäßen Abgasrückführsystems mit einer anderen Stellung der beiden Ventile; und
• Fig. 3 in einer perspektivischen Darstellung eine weitere Schnittansicht des in Fig. 1 und 2 gezeigten Teils.

The invention will be explained in more detail with reference to an embodiment shown by way of example in the drawings. Show it:

• Figure 1 is a perspective sectional view of a part of the exhaust gas recirculation system according to the invention.
• FIG. 2 shows a side sectional view of the part of the exhaust gas recirculation system according to the invention shown in FIG. 1 with a different position of the two valves; FIG. and
• Fig. 3 is a perspective view of a further sectional view of the part shown in FIGS. 1 and 2.

Detailed description of a preferred embodiment of the invention

Fig. 1 shows in a perspective view a portion of this exhaust gas recirculation system according to the invention, which contains in particular a common valve housing 18 of the exhaust gas recirculation valve and the bypass valve. In the split embodiment, both valves are located downstream of a radiator (not shown). In the illustrated section, only the end of a cooling line 14 can be seen, which extends in the section, not shown, through an exhaust gas cooler, so that the recirculated exhaust gas is cooled. In order to adjust and regulate the temperature of the recirculated exhaust gas, a bypass line 16 is provided in addition to the cooling line 14. In the region of the two valves, the exhaust gas recirculation valve with the valve element 10 and the bypass valve 12, the two exhaust gas streams, which respectively flow in the direction A through the cooling 14 and the bypass line 16, to a common exhaust gas flow at the desired temperature. The temperature can be adjusted in particular by providing a bypass flap 12 as the bypass valve in the embodiment shown, which can close either the cooling line 14 or the bypass line 16 in the embodiment shown, or in appropriate intermediate positions the flow resistance at the end of one of the two lines can adjust that from one of the two lines a desired reduced partial flow is adjusted.

In Fig. 1 that position of the bypass valve 12 is shown, in which the cooling line 14 is closed. It should already be noted at this point on Fig. 2, in which that position of the bypass valve 12 is shown, in which the bypass line 16 is closed. By suitable positions between these two extremes, one of the two partial flows can be adjusted so that a reduced amount of cooled or not cooled exhaust gas enters the exhaust gas recirculation line.

The bypass valve is, as will be explained in more detail below with reference to FIG. 3, mounted on a folding axis 22 and by a suitable (not shown) drive, which is located outside of the valve housing 18, to the desired angular position. The possibility of adjustment applies in the same way and regardless of the setting of the bypass flap 12 for the valve element 10 of the exhaust gas recirculation valve. This is connected in the embodiment shown within the single, common valve housing 18 via two legs 20 to its pivot axis 24, as apparent from Fig. 3. In the illustrated embodiment, the bypass flap 12 is therefore pivotable between the legs 20 of the exhaust gas recirculation valve. The exhaust gas recirculation valve with the valve element 10 can be brought into abutment on its valve seat 26 in such a way that the exhaust gas recirculation line (not shown) is completely closed so that, in other words, no exhaust gas is recirculated. By any intermediate positions, such as shown in Fig. 1, in other words between the fully closed, applied to the valve seat 26 and shown in Fig. 2, fully open position, the amount of recirculated exhaust gas can be adjusted. As mentioned, regardless of this, by means of the bypass flap 12, the regulation the temperature of the recirculated gas. To the valve element 10 of the exhaust gas recirculation valve is to say that this example, according to the EP 03 029 491 the applicant and all documents referred to therein. In particular, the disclosure of said application and the documents referred to therein with respect to the design of the exhaust gas recirculation valve is the subject of the present application.

To the embodiment shown is still to mention that the common valve housing 18 is designed such that therein at least one end portion of both the cooling 14 and the bypass line 16 is arranged. Furthermore, the valve housing 18 between the cooling 14 and the bypass line 16 and the adjoining the valve seat 26 exhaust gas recirculation line a bend or a bend of about 90 °, whereby the single, common valve housing 18 for the two valves 10, 12 particularly simple to realize. In the example shown, the valve seat 26 of the exhaust gas recirculation valve is inserted as a separate component in the valve housing 18. It should also be mentioned that the cooling line 14 may be at least partially "around the bypass line 16" around. For example, sections of the cooling line 14 may extend in the region "behind" the bypass line 16, which region is covered by the bypass line 16 in the view in FIG. 1.

In Fig. 2, as shown in Fig. 1 cut open valve housing 18 can be seen in a side view. It follows clearly that the axes 22, 24 of the exhaust gas recirculation valve and the bypass flap 12 are aligned with each other and have a common axis center. For the exhaust gas recirculation valve with the valve element 10 results in the arrangement of its pivot axis 24 eccentric with respect to the valve seat 26. Further, the valve element 10 is eccentric as such with respect to its pivot axis 24 not only by the connection by means of the legs 20, but also in a direction perpendicular thereto, namely in a direction to the right as shown in Fig. 2. In Fig. 2, a position of the two valves is further shown, in which the bypass valve 12, the bypass line 16 completely closes, so that only cooled, flowing through the cooling line 14 exhaust gas is returned. Further, the valve element 10 of the exhaust gas recirculation valve is fully opened, so that the maximum recirculation of exhaust gas takes place. Here, the valve element 10 is at least largely accommodated in the recess 28 of the valve housing 18, so that the flow in the valve housing is influenced comparatively slightly.

Details of the mounting of the folding axis 22 of the bypass flap 12 and of the pivot axis 24 of the valve element 10 are shown in FIG. 3. In the exemplary embodiment shown, both the folding 22 and the pivot axis 24 are mounted in the wall of the valve housing. In the view of Fig. 3, the folding axis 22 is mounted in the left wall, and the pivot axis 24 in the right wall. In addition, the folding axis 22 is mounted as follows in the pivot axis 24. The pivot axis 24 extends only to one of the two legs 20, with which the valve element 10 is connected to the pivot axis 24 (as shown in FIG. 3 to the right leg). At the end of the pivot axis 24 in the region of this leg, a bore or recess 30 is formed, in which the folding axis 22 is mounted. For this purpose, the folding axis 22 on a protruding pin 32 which projects into the recess 30 in. In the area between the two legs 20, the bypass flap 12 is connected to the folding axis 22. In the example shown, the (left) leg 20, which is remote from the end of the pivot axis 24, is mounted on a portion of the folding axis 22. By the described storage is pivoting or flaps of the two valves 10, 12 independently possible. Upon pivoting of the valve element 10 rotates If the folding axis 22 is rotated, this rotates in the example shown in the "eyelet" of the left leg 20 and, with its pin 32 in the recess 30 of the pivot axis 24th In this case, the bypass flap 12 is pivoted between the two legs 20. The (not shown) drives both the folding 22 and the pivot axis 24 are outside the valve housing and are independently operable. In Fig. 3, finally, a flange 34 can be seen, by means of which the valve housing 18 can be connected to an (not shown) exhaust gas recirculation line, for example by fasteners such as screws, which are guided through the opening 36 shown by way of example.

Claims (9)

Exhaust gas recirculation system with an exhaust gas recirculation valve, which has a single valve element (10), with which an exhaust gas recirculation line is closed, and a separate bypass valve (12), with a cooling (14) and / or a bypass line (16) is closable, wherein the exhaust gas recirculation valve (10) and the bypass valve (12) are arranged in a common valve housing (18). Exhaust gas recirculation system according to claim 1,
characterized in that
the exhaust gas recirculation valve (10) and the bypass valve (12) are arranged offset in the flow direction (A). Exhaust gas recirculation system according to claim 1 or 2,
characterized in that
the exhaust gas recirculation valve (10) and / or the bypass valve (12) are pivotable or foldable. Exhaust gas recirculation system according to claim 3,
characterized in that
both the exhaust gas recirculation (10) and the bypass valve (12) are pivotable or hinged, and the pivot (24) and folding axes (22) have a common axis center. Exhaust gas recirculation system according to claim 4,
characterized in that
the folding axis (22) of the bypass valve (12) in the pivot axis (24) of the exhaust gas recirculation valve (10) is mounted. Exhaust gas recirculation system according to one of claims 3 to 5,
characterized in that
the bypass valve (12) is located adjacent to at least one leg (20) with which the exhaust gas recirculation valve (10) is connected to its pivot axis (24). Exhaust gas recirculation system according to one of claims 3 to 6,
characterized in that
two legs (20) are provided, with which the exhaust gas recirculation valve (10) with its pivot axis (24) is connected, and the bypass valve (12) between the two legs (20) is hindurchschwenkbar. Exhaust gas recirculation system according to one of the preceding claims,
characterized in that
the valve housing (18) forms an angle of preferably approximately 90 ° between the direction of the cooling (14) and / or the bypass line (16) and the exhaust gas recirculation line. Exhaust gas recirculation system according to one of the preceding claims,
characterized in that
the valve housing (18) has a recess (28) in which the valve element (10) of the exhaust gas recirculation valve is at least partially accommodated in the open state.

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