WO2006099965A1

WO2006099965A1 - Air-induction unit for an internal combustion engine, comprising a bypass flap assembly that can be inserted

Info

Publication number: WO2006099965A1
Application number: PCT/EP2006/002304
Authority: WO
Inventors: Gerhard Gruber; Stephan Läpple
Original assignee: Daimlerchrysler Ag
Priority date: 2005-03-19
Filing date: 2006-03-14
Publication date: 2006-09-28
Also published as: DE102005012842A1

Abstract

The invention relates to an air-induction unit (1) for an internal combustion engine. Said unit comprises an exhaust-gas recirculation channel (2) with a passage (4), into which a bypass flap assembly can be inserted (6), said assembly comprising at least one bypass flap (10), which is rotatably fixed to a shaft (8) that can be driven by an actuator and a fixing flange (12) that is mounted in a floating manner on the shaft (8). According to the invention, the bypass flap (10) can be pivoted between a first position (31), in which an upstream section (32) of the exhaust-gas recirculation channel (2) is connected to a cooling channel (24) that leads to an exhaust-gas cooling unit and a second position (33), in which the upstream section (32) of the exhaust-gas recirculation channel (2) is connected to a bypass channel (26) that bypasses the exhaust-gas cooling unit. The bypass flap (10) is set up in the first (31) or second position (33) to conduct the exhaust-gas flow from the upstream section (32) of the exhaust-gas recirculation channel (2) into the cooling channel (24) or the bypass channel (26) without a change of direction.

Description

Air intake device for an internal combustion engine with deployable bypass valve device

The invention relates to an air intake device for an internal combustion engine comprising an exhaust gas recirculation channel with a through hole, in which a bypass valve device can be used which comprises at least one bypass flap rotatably mounted on a shaft driven by an actuator and a mounting flange cantilevered over the shaft, the bypass flap between a first position, in which an upstream part of the exhaust gas recirculation passage with a to a

Is connected exhaust gas cooling device leading cooling channel and a second position in which the upstream part of the exhaust gas recirculation passage is connected to a bypass channel bypassing the exhaust gas cooler, according to the preamble of claim 1.

Such an air intake device is known from DE 103 41 393 B3, in which the bypass flap is fixed like a flag on the shaft and the shaft is arranged directly on a partition wall between the cooling channel and the bypass channel, wherein the bypass flap both in the first position and in the second position, the exhaust gas flow under deflection in the cooling channel or in the bypass channel passes. However, the deflection of the exhaust gas flow causes undesirable flow losses in the exhaust gas flow.

The invention is the object of an air intake device of the type mentioned in such a way that the above-mentioned disadvantages are avoided.

This object is achieved by the features of claim 1.

By the bypass flap in the first or in the second position assumes a position in which it directs the exhaust gas flow from the upstream part of the exhaust gas recirculation channel without directional deflection in the cooling channel or in the bypass channel, flow losses due to a deflection of the flow direction can be avoided. As a result, there is a higher exhaust pressure in the exhaust gas recirculation channel, which has a positive effect on the pollutant emissions.

In the dependent claims advantageous embodiments of the invention are shown.

According to a particularly preferable embodiment, the bypass valve takes in the first position, a position a in which it directs the exhaust gas flow ^~ without Ümreήkuncf irr the ^"Kühlkanar. This carries the bypass valve in an advantageous manner not to increase due to the presence of the exhaust gas cooling device in the cooling channel anyway greater resistance to flow, so that the pressure of the recirculated exhaust gas through the cooling channel is greater, which ultimately results in a reduction of the exhaust gas pollution.The said measure also contributes to the fact that the pressure losses in the cooling channel and those in the bypass channel are approximately the same size, which means that the exhaust gas recirculation rates are approximately the same in cooling mode and in bypass mode.

The deflection-free position of the bypass flap can for example be realized in that the bypass flap is flat and symmetrical to the shaft and that a central axis of the shaft is in a wall of the upstream part of the exhaust gas recirculation channel and a wall of the cooling channel containing surface and the central axes and the cross sections the upstream part of the exhaust gas recirculation passage and the cooling passage are aligned with each other.

Since the bypass damper is symmetrical with respect to the shaft, it is torque-free when it flows, resulting in low actuating forces. The end edges of the preferably rectangular bypass flap may be formed as sealing surfaces. Such a simple contour can be manufactured with high accuracy at relatively low cost as a common part for different types.

According to a further measure, the bypass channel opens substantially transversely into a branch of the exhaust gas recirculation channel. In this case, ^~ the ^~ Vefzweigürig ^{'Wänölüήgsäbschnϊtte} ^"irrirtr partially circular cross-section included, which sealing surfaces formed opposite the bypass damper This part-circular surfaces form wall surfaces of a cylinder from whose central axis is collinear with the central axis of the shaft and with the through hole to which the bypass valve unit at the exhaust gas recirculation passage. is included. According to a first embodiment, the bypass passage is arranged substantially coplanar with the exhaust gas recirculation passage and the cooling passage. Alternatively, the bypass channel can be arranged at least in the region of the branch transverse to a plane containing the exhaust gas recirculation channel and the cooling channel.

For cooling the bypass flap unit, particularly preferably walls of the exhaust gas recirculation channel and / or the coolant channel and / or the bypass channel at least in the region of the junction on cooling chambers, which are flowed through by coolant. Then, the entire bypass valve unit can be changed without the coolant circuit would have to be opened.

drawing

Embodiments of the invention are illustrated in the drawing. In the drawing shows

FIG. 1 is a cross-sectional view of a bypass flap device held in an exhaust gas recirculation passage according to a first embodiment of the invention; FIG.

Fig. 2 is a cross-sectional view taken along the line II- ^" TI ^" of Fig. 1 ^" ; ^"

3 shows a cross-sectional view of a bypass flap device held in an exhaust gas recirculation channel according to a further embodiment of the invention;

4 shows a cross-sectional view along the line IV-IV of Fig.l. Identical and same-acting components and assemblies of different embodiments are denoted below by the same reference numerals.

Description of the embodiments

The air intake device for an internal combustion engine, generally designated 1 in FIGS. 1 and 2, includes an exhaust gas recirculation passage 2 with a through-bore 4 into which a bypass flap device 6 is inserted. It comprises a bypass flap 10 which is rotatably mounted on a shaft 8 which can not be shown for reasons of scale, and a mounting flange 12 which cantiles the shaft 8. More specifically, the shaft 8 projects through a central through-bore 14 of the flange 12 and is there by axial and radial bearings stored. The through hole 4 radially superior mounting flange 12 is detachably connected to a wall 16 of the exhaust gas recirculation passage 2, for example by screwing. Thus, the bypass flap device 6 can be pulled out of the through-hole 4 as a whole or inserted into it. About an attached to the end of the shaft 8 lever 18, the shaft 8 can be driven by the adjusting device, such as a vacuum box.

Particularly preferably, the bypass flap 10 is arranged symmetrically with respect to the shaft 8 and formed flat in a rectangular shape. Furthermore, all four edges 20a, 20b, 20c, 20d of the bypass flap 10 are designed as sealing surfaces with respect to the exhaust gas recirculation channel 2.

The through hole 4 for the bypass valve device 6 is arranged at a branch 22 of the exhaust gas recirculation channel 2, at which it is in a cooling channel 24 and branches a bypass channel 26. The cooling channel 24 includes a per se known, not shown cooling device for cooling the exhaust gas flowing through it, the bypass channel 26 serves to guide exhaust around the cooling device around. In this case, the branch 22 has wall sections 28 with a part-circular cross section, which form radial, preferably prominent or protruding sealing surfaces 30a, 30b relative to the shaft 8 relative to the associated sealing surfaces 20a, 20b of the bypass flap. These surfaces 30a, 30b form wall surfaces of a cylinder whose central axis is collinear with the central axis of the shaft 8 and also the through-bore 4, on which the bypass flap device 6 is received on the exhaust gas recirculation channel 2.

Furthermore, upper and lower sealing surfaces 30c, 30d are also provided in planes perpendicular to the shaft 8 on the inner surfaces of the exhaust gas recirculation channel 2 in the region of the branch 22, which cooperate with the corresponding sealing surfaces 20c, 20d of the bypass flap 10. In this case, for example, the sealing surface 30c is formed on the mounting flange 12.

By driving the actuator, the bypass valve 10-between. e ± ner_ersJben. 31, in which an upstream part 32 of the exhaust gas recirculation passage 2 is connected to the cooling passage 24 leading to the exhaust cooling device, and a second position 33, in which the upstream part 32 of the exhaust gas recirculation passage 2 is connected to the bypass passage 26, pivotable (FIG. Figure 2). In addition, all the intermediate position of the bypass valve 10 are possible, ie that the exhaust gas guided in the exhaust gas recirculation channel 2 is partially conducted into the cooling channel 24 and into the bypass channel 26. According to a particularly preferable embodiment, in the first position 31, the bypass flap 10 assumes a position in which it directs the exhaust gas flow without deflection into the cooling channel 24. The deflection-free position of the bypass flap 10 can be realized, for example, in that a central axis of the shaft 8 is in a wall 34 of the upstream part 32 of the exhaust gas recirculation passage 2 and a wall 36 of the cooling channel 24 containing surface and the center axes and the cross sections of the upstream part 32nd the exhaust gas recirculation channel 2 and the cooling channel 24 are aligned with each other and run steadily.

According to the embodiment of Fig.l and Fig.2, the exhaust gas recirculation passage 2, the bypass passage 26 and the cooling passage 24 are arranged substantially coplanar.

Alternatively, the bypass channel can be arranged at least in the region of the branch 22 transversely to a plane which contains the exhaust gas recirculation channel 2 and the cooling channel 24. This embodiment is shown in Fig.3 and Fig.4. In both cases, the execution of the bypass valve device 6 is identical.

In both embodiments, the walls 34, 36 of the exhaust gas recirculation channel 2 and / or the cooling channel 24 and / or the bypass channel 26, in particular in the region of the branch 22 cooling chambers 38, which are flowed through by coolant, such as water and an indirect cooling of the bypass valve means 6 and Also cause the exhaust gas, since the heat of the bypass valve device 6 is transmitted by heat conduction via the flange 12 and / or by thermal radiation to the cooling chambers 38 in the walls 34, 36. Alternatively, a direct cooling of the bypass valve device 6 may be provided.

Against this background, the bypass flap 10 is pivoted into the first position 31, when the exhaust gas in the exhaust gas recirculation passage 2 is to be passed into the cooling channel 24 and cooled there, for example, in already warm-running internal combustion engine. In the second, the bypass channel 26 with exhaust gas supplying position 33, the bypass valve 10 is however brought when no cooling of the exhaust gas should take place, which is the case, for example, shortly after a cold start of the internal combustion engine. In between, the bypass door 10 may take any position to partially guide exhaust gas into the bypass passage 26 as well as into the cooling passage 24.

Claims

claims

1. An air intake device (1) for an internal combustion engine comprising an exhaust gas recirculation passage (2) with a passage opening (4) into which a Bypassklappen- device (6) can be inserted, the at least one rotatably mounted on one of a setting device driven shaft (8) bypass flap (10) and one the wave

(8) comprises a cantilever mounting flange (12), the bypass flap (10) being connected between a first position (31) in which an upstream part (32) of the exhaust gas recirculation passage (2) is connected to a cooling passage (24) leading to an exhaust gas cooling device and a second position (33) in which the upstream part (32) of the exhaust gas recirculation passage (2) is provided with a bypass passage bypassing the exhaust gas cooling means

(26), is pivotable, characterized in that the bypass flap (10) in the first position (31) or in the second position (33 " ^~ eirie Läge ^""" eTήrfirnmtV ^" in ^" we ^' lcher ^~ they the exhaust gas flow from the upstream part (32) of the

Exhaust gas recirculation channel (2) without directional deflection in the

Cooling channel (24) or in the bypass channel (26) passes.

2. Air intake device according to claim 1, characterized in that the bypass flap (10) in the first position (31) a Situation in which it directs the exhaust gas flow without deflection in the cooling channel (24).

3. Air intake device according to claim 2, characterized in that the bypass flap (10) is rectangular and symmetrical to the shaft (8) and that a central axis of the shaft (8) in a wall (34) of the upstream part (32) of the exhaust gas recirculation passage (2) and a wall (36) of the cooling channel (24) containing surface is located.

4. Air intake device according to claim 2 or 3, characterized in that the central axes and the cross sections of the upstream part (32) of the exhaust gas recirculation passage (2) and the cooling passage (24) are aligned.

5. Air intake device according to claim 4, characterized in that the bypass channel (26) substantially transversely in a branch (22) of the exhaust gas recirculation passage (2) opens, at which it branches into the bypass channel (26) and the cooling channel (24).

6. Air intake device according to claim 5, characterized in that the branch (22) contains at least one wall section (28) with a part-circular cross section, which at least one sealing surface (30a, 30b) relative to the bypass flap (10) is formed.

7. Air intake device according to claim 5 or 6, characterized in that the bypass channel (26) is arranged substantially komplanar with the exhaust gas recirculation passage (2) and the cooling channel (24).

8. Air intake device according to claim 5 or 6, characterized in that the bypass channel (26) at least in the region of the branch (22) is transverse to a plane containing the exhaust gas recirculation passage (2) and the cooling channel (24).

9. Air intake device according to at least one of the preceding claims, characterized in that the end edges of the bypass flap (10) as

Sealing surfaces (20a, 20b, 20c, 2Od) are formed.

10. Air intake device according to at least one of the preceding claims, characterized in that for cooling the bypass flap device (6) walls (34, 36) of the exhaust gas recirculation channel (2) and / or the KühlkanaTs (24) and / or the ^~ bypass channel - (26 ) at least in the region of the branch (22) cooling chambers (38), which are flowed through by coolant.