WO2009056214A1

WO2009056214A1 - Internal combustion engine comprising an exhaust gas turbocharger

Info

Publication number: WO2009056214A1
Application number: PCT/EP2008/008617
Authority: WO
Inventors: Peter Knauel; Talat KÖMÜRCÜOGLU; Timo Schmidt
Original assignee: Daimler Ag
Priority date: 2007-11-02
Filing date: 2008-10-11
Publication date: 2009-05-07
Also published as: DE102007052244A1

Abstract

The invention relates to an internal combustion engine comprising an exhaust gas turbocharger and an exhaust gas tract (3), which has an exhaust gas line (6) with a longitudinal axis (36), an exhaust gas conduction section (13) of the exhaust gas turbocharger (9), through which gas can flow, being located in the exhaust gas line (6), and comprising a closing device (30) with a closing body (31) and a lever arm (34) that has a maximum displacement angle (ß). The closing body (31) is located inside the exhaust gas line (6), upstream of the exhaust gas conduction section (13), in such a way that it can adopt a closing position, in which the closing body (31) can seal a flow surface (37). According to the invention, the closing body (31) is positioned in the exhaust gas line (6) in such a way that a closing angle (α) of less than 90° is formed between the flow surface (37) covered by the closing body (31) and the longitudinal axis (36). The invention is used predominantly in vehicle construction.

Description

Internal combustion engine with an exhaust gas turbocharger

The invention relates to an internal combustion engine with an exhaust gas turbocharger according to the preamble of claim 1.

To increase the performance of internal combustion engines, it is widely used to provide a bypass line for so-called bypassing of a turbine wheel of the exhaust gas turbocharger in the arrangement of a single exhaust gas turbocharger in an exhaust tract of the internal combustion engine or to use a second exhaust gas turbocharger in addition to a first exhaust gas turbocharger, with a parallel or a serial arrangement of the turbocharger possible is.

However, there are operating ranges of the internal combustion engine in which a bypass or a simultaneous operation of the exhaust gas turbocharger is not necessary. To control the operation of the exhaust gas turbocharger control elements in the form of locking devices, which are electronically and / or mechanically and / or pneumatically adjustable used. These closing devices are usually provided in an exhaust gas duct section of the internal combustion engine upstream of a turbine wheel rotatably mounted in the exhaust gas guide section in a free flow cross section, which is to be blocked or released.

The closing devices have a closing body which is positioned in the free flow cross section. Of the Closing body is usually rotatable for positioning about an axis of rotation of the closing device. The closing body is movable between two stop positions, wherein the first stop position is a so-called closed position in which the closing body as completely as possible closes the free flow cross-section, and the second stop position is a so-called opening position in which the closing body as far as the free flow cross-section is possible for the locking device releases. Between these two stop positions, a so-called movement angle is formed.

In general, so-called boost pressure control valves are used as a closing device, which allow targeted control of the positioning of the closing body in response to a supercharging on a compressor supercharging, so that the corresponding, free flow cross-section adapted to the desired operating condition of the internal combustion engine, fully or partially enabled or disabled can be. In this case, the closing body is positioned in a position between the two stop positions arranged intermediate position or one of the two stop positions.

The disadvantage of these locking devices is the fact that they have a small movement angle due to the design. This movement angle is usually between about 45 ° and 65 °. Due to the small movement angle, they constitute a flow obstacle in the opening position, in which the free flow cross section should be completely free, since the closing body can not be completely removed from the free flow cross section due to its limited maximum movement angle.

From JP 021 53 226 Al an internal combustion engine with an exhaust gas turbocharger emerges, wherein the internal combustion engine has an exhaust tract with an exhaust pipe, in which an exhaust gas guide portion of the exhaust gas turbocharger is arranged. Upstream of the exhaust gas guide section, a closing device for releasing or blocking a free flow cross section of the exhaust gas line is provided in the exhaust gas line. The closing device is designed in the form of a non-return valve and has a closing body, which is designed to cover the free flow cross-section. The closing device furthermore has an axis of rotation about which the closing body is rotatably positioned. In an unobstructed state, the closing body has a maximum angle of movement of 360 ° about the axis of rotation. An advantage of the non-return valve can be seen in this large movement angle, since in a built-in state of the closure device thus the closing body is completely removed from the free flow cross-section, so that a disturbance of the flow due to the closing body can be excluded. A disadvantage, however, is to be seen in the fact that an influence on the release or the blocking of the free flow cross-section takes place exclusively thermodynamically as a function of the applied pressure at the non-return valve, that is, the pressure upstream of a turbine wheel. Targeted control of the non-return valve is not possible.

The object of the present invention is to design an internal combustion engine with an exhaust gas turbocharger, wherein arranged in an exhaust tract of the engine closing body of a closing device, which allows a targeted influence on the positioning of the closing body is positioned in the exhaust tract in a closed position such that the Closing body in an open position is completely removed from a free flow cross-section.

This object is achieved with an internal combustion engine with the features of claim 1. The dependent claims indicate expedient developments. The internal combustion engine according to the invention with an exhaust gas turbocharger has a closing body which is positioned in the closed position in the exhaust pipe, that between the covered by the closing body flow area and a longitudinal axis of the exhaust pipe, a closing angle α is formed, which is smaller than 90 °. This means that the closing body is not positioned in the closed position, as usual horizontally to the longitudinal axis in the free flow cross-section, but is arranged inclined relative to the longitudinal axis in the exhaust pipe. In this case, the closing body is arranged inclined in the closed position such that in the open position of the closing body, the free flow cross-section is completely released. Ideally, the closing angle α corresponds to the maximum possible movement angle β, which is formed between the two stop positions, whereby a maximum possible number of intermediate positions can be used.

The advantage of this invention is the fact that the closing body in a position in which the free flow cross section should be fully opened, completely removed from the free flow cross section and thus does not appear as a flow obstacle in the free flow cross section in appearance. As a result, a significant increase in performance of the exhaust gas turbocharger can be realized. Likewise, a smaller exhaust gas turbocharger can be used, since the power losses of the exhaust gas turbocharger influencing flow losses no longer have to be compensated for the size of the exhaust gas turbocharger.

In one embodiment, the closing body has a circular diameter which corresponds to a diameter of the flow area. A free, arranged perpendicular to the longitudinal axis of the exhaust pipe flow cross-section of the exhaust gas line is formed elliptical, wherein a largest ellipse diameter corresponds to the circle diameter and a smallest ellipse diameter of the relationship KED = sinα-DS follows. By virtue of this configuration of the free flow cross-section, it is therefore possible to use any commercially available, generally circular closure body, so that cost-effectively installed closing devices in the form of wastegate valves can continue to be used.

In a further refinement, the exhaust gas tract has a further exhaust gas line, which is positioned branching off from the exhaust gas line upstream of the closing body, so that the exhaust gas guide section can be bypassed with the aid of the closing body and is not acted upon by exhaust gas flowing out of the internal combustion engine.

In a further embodiment, a further exhaust gas guide section of a further exhaust gas turbocharger is arranged downstream of the branch in the further exhaust gas line, so that a controllable operation of the two exhaust gas turbochargers with the aid of the closing device is possible.

Further advantages and expedient embodiments of the invention can be taken from the claims, the description of the figures and the drawings. Showing:

1 is a schematic representation of an internal combustion engine according to the invention with an exhaust gas turbocharger and another exhaust gas turbocharger, Fig. 2 in a longitudinal section an exhaust pipe of a

Exhaust tract of the internal combustion engine gem. 1 with a closing device in a closed position,

3 shows a longitudinal section of the exhaust pipe with the closing device in an open position,

4 is a sectional view of a cross section through the exhaust pipe according to FIG. Fig. 3 along the section line A - A and

5 is a sectional view of a cross section through the exhaust pipe according to FIG. Fig. 3 along the section line B - B.

In the figures, all the same or equivalent components are provided with the same reference numerals.

The internal combustion engine 1 shown in FIG. 1 has a fresh air line 2 and an exhaust tract 3. During operation, the internal combustion engine 1 sucks in combustion air via the fresh air train 2, which combustion air is discharged via the exhaust gas tract 3 as exhaust gas after a combustion in the internal combustion engine 1 that has been supplied with fuel.

The fresh air line 2 has a charge air line 4, which is connected at its end facing the internal combustion engine 1 arranged with the internal combustion engine 1. Upstream of the internal combustion engine 1, a charge air cooler 5 is expediently arranged in the charge air line 4 for cooling sucked combustion air.

The exhaust gas tract 3 has an exhaust gas line 6, at whose end facing away from the engine 1 arranged exhaust gas aftertreatment system 7 for exhaust aftertreatment, which is designed in the form of a soot filter and / or catalyst and / or SCR system.

Furthermore, the internal combustion engine 1 is associated with a control and control unit 8 for controlling and controlling numerous functions. About the control and control unit 8 in particular the fuel supply is adjustable.

The internal combustion engine 1 is associated with an exhaust gas turbocharger 9 and another exhaust gas turbocharger 10. The exhaust-gas turbocharger 9 and the further exhaust-gas turbocharger 10 have a housing 11 or a further housing 12 which has a flow-through exhaust-gas guide section 13 or a further exhaust-gas guide section 14, a flow-through air guide section 15 or a further air-flow guide section 16 and a bearing section 17 or a further bearing section 18 comprise, wherein the air guide portion 15 and the further air guide portion 16 respectively in the fresh air line 2 and the exhaust gas guide portion 13 and the further exhaust gas guide portion 14 is disposed in the exhaust tract 3 respectively. The bearing section 17 and the further bearing section 18 are positioned between the air guide section 15 and the exhaust gas guide section 13 or between the further air guide section 16 and the further exhaust gas guide section 14.

The exhaust-gas turbocharger 9 or the further exhaust-gas turbocharger 10 each have a running gear 19 mounted in the housing 11 or further running gear 20 mounted in the further housing 12, which has a compressor wheel 21 for drawing in and compressing combustion air, a turbine wheel 22 for expanding exhaust gas and a compressor wheel 21 rotatably connected to the turbine 22 shaft 23 with a rotation axis 24 and a further compressor 25 for Suction and compression of combustion air, a further turbine wheel 26 for expansion of exhaust gas and the further compressor wheel 25 with the other turbine 26 rotatably connecting further shaft 27 having a further axis of rotation 28 includes. The compressor wheel 21 is in the air guide section 15, the turbine wheel 22 is in the exhaust guide section 13 and the shaft 23 is in the bearing section 17 or the further compressor 25 is in the further air guide section 16, the other turbine 26 is in the further exhaust guide section 14 and the other shaft 27 is in further bearing portion 18 rotatably arranged. The exhaust gas guide portion 13 is positioned in the exhaust pipe 6 upstream of the exhaust aftertreatment system 7.

For arranging the further exhaust gas guide section 14 in the exhaust tract 3 of the internal combustion engine 1, the exhaust tract 3 is assigned a further exhaust pipe 29, which is arranged branching off from the exhaust pipe 6 upstream of the exhaust gas guide section 13. The further air guide section 16 is positioned upstream of the air guide section 15 in the intake tract 2.

The arrangement of the two exhaust gas turbochargers 9, 10 shown in FIG. 1 permits a parallel operation of the two exhaust gas turbochargers 9, 10, wherein the exhaust pipe 6 is fully or partially opened by the closing device 30, so that the turbine wheels 22, 26 can be acted upon by exhaust gas. If the exhaust pipe 6 is closed by means of the closing device 30, only the further turbine wheel 26 can be acted upon by exhaust gas.

In a further, not shown embodiment, the two exhaust gas turbochargers 9, 10 are arranged so that a serial operation of the two exhaust gas turbochargers 9, 10 possible is. In this case, each exhaust gas guide section 13, 14 is associated with a respective bypass line of the exhaust tract 3, in each of which the closing device 30 is positioned. Also, only one exhaust gas guide section, the exhaust gas guide section 13 or the further exhaust gas guide section 14 could be assigned a bypass line in which the closing device 30 is positioned. If the corresponding bypass line closed by means of the closing device 30, the corresponding turbine wheel 22, 26 can be acted upon by exhaust gas. If, on the other hand, the corresponding bypass line is completely or partially opened by means of the closing device 30, the corresponding turbine wheel 22, 26 is not or only partially acted upon by the exhaust gas.

2 shows in a longitudinal section the exhaust pipe 6 with a closing device 30. The closing device 30 comprises a closing body 31 and an adjusting device 32. The closing device 30 is designed in the form of a conventional wastegate valve. A positioning of the closing body 31 takes place with the aid of an upstream of the internal combustion engine 1 in the charge air line 4 adjacent charge pressure. The closing device 30 is shown in a closed position, wherein the closing body 31 is positioned in a free flow cross-section 33 of the exhaust pipe 6.

The closing body 31 is movable by means of a lever arm 34 of the adjusting device 32, wherein the closing body 31 is generally connected almost rigidly to the lever arm 34. The lever arm 34 is rotatable about an axis of rotation 35 of the adjusting device 32, wherein a movement angle ß of 60 ° is included between a first stop position of the lever arm 34 and a second stop position of the lever arm 34. The movement angle ß is manufacturer-dependent and typically varies in a range between about 45 ° and 65 °. Since the closing body 31 is connected to the lever arm 34 almost rigidly, the closing body 31 on the movement angle ß of the lever arm 34.

2, the lever arm 34 in the second stop position shown in dashed lines, wherein the second stop position of the opening position of the locking device 30 gem. Fig. 3 corresponds.

According to the invention, the closing body 31 is inclined in the closed position with respect to a longitudinal axis 36 of the exhaust pipe 6, such that between a flow area 37 covered by the closing body 31 and the longitudinal axis 36

Closing angle α is formed, which corresponds to the movement angle ß. The flow surface 37, which is designed to be completely or partially closed or completely released by the closing body 31, has a diameter D.

3 shows the closing body 31 in the opening position of the closing device 30. In order for the closing body 31 to be arranged completely outside the flow in the opening position, the exhaust pipe 6 or the corresponding line section has a recess 38, which the closing device 30 is configured to receive. Ideally, the closing device 30 is arranged completely in the recess 38. It can also be arranged outside the exhaust pipe 6 parts of the locking device 30. However, a seal of the flow against to pay attention to the environment.

Advantageously, a cross-section of the exhaust gas conduit 6 is circular in shape through the flow surface 37 (see Fig. A) ₁ so that ideally the free flow cross-section 33 is elliptical (see Fig. 5). A largest ellipse diameter GED corresponds to the circle diameter DS and a smallest ellipse diameter KED follows the relationship KED = sinα-DS.

For secure sealing of the flow surface 37 to be covered, the closing body 31 is made larger at its outer periphery than the flow surface 37 to be covered, so that a predominantly circular bulge 39 in the region of the flow surface 37 to be covered is necessary. Since this bulge 39 can be kept relatively small in comparison to the free flow cross-section 33, any flow irregularities which may occur here when the free flow cross-section 33 is open are negligible.

Claims

claims

1. Internal combustion engine with an exhaust gas turbocharger, and an exhaust tract (3) having an exhaust pipe (6) having a longitudinal axis (36), wherein a flow-through exhaust guide portion (13) of the exhaust gas turbocharger (9) in the exhaust pipe (6) is arranged, and with a closing device (30), which has a closing body (31) and a lever arm (34) with a maximum travel angle

(β), which is smaller than 90 °, wherein the closing body (31) upstream of the exhaust gas guide portion (13) within the exhaust pipe (6) a closing position is arranged ingesturable, in which the closing body (31) a flow surface (37) formed closable is, characterized in that the closing body (31) is positioned in the closed position in the exhaust pipe (6), that between the closing body (31) covered flow area (37) and the longitudinal axis (36) a closing angle (α) is formed , which is smaller than 90 °.

2. Internal combustion engine according to claim 1, characterized in that the closing angle (α) corresponds to the maximum travel angle (ß).

3. Internal combustion engine according to claim 1 or 2, characterized in that the closing body (31) has a circular diameter (DS), which corresponds to a diameter (D) of the flow area to be covered, and a free, perpendicular to the longitudinal axis (36) positioned flow cross-section (33 ) of the exhaust pipe (6) is elliptical, wherein a largest ellipse diameter (GED) corresponds to the circle diameter (DS) and a smallest ellipse diameter (KED) of the relationship

KED = sinα-DS follows.

4. Internal combustion engine according to one of claims 1 to 3, characterized in that the exhaust gas tract (3) has a further exhaust pipe (29), which is upstream of the closing device (30) of the exhaust pipe (6) is branched off.

5. Internal combustion engine according to claim 4, characterized in that downstream of the branch in the further exhaust pipe (29), a further exhaust gas guide portion (14) of a further exhaust gas turbocharger (10) is arranged.