EGR SYSTEM WITH PARTICLE FILTER AND WASTEGATE

Abstract

The invention relates to an exhaust gas conducting system for a gasoline engine, comprising an exhaust gas line which can be connected to an exhaust manifold of the gasoline engine, an inlet line which can be connected to an intake manifold of the gasoline engine, and a turbine which is arranged in the exhaust gas line. At least one exhaust gas recirculation line is provided which opens into the inlet line, and the exhaust gas line has a bypass line which opens into the exhaust gas line downstream of the turbine, wherein a) the exhaust gas recirculation line branches off upstream of the turbine, and the bypass line branches off to the exhaust gas recirculation line or b) the bypass line branches off upstream of the turbine, and the exhaust gas recirculation line branches off to the bypass line, wherein c) at least one particle filter is arranged in the exhaust gas recirculation line or in the bypass line upstream of the exhaust gas recirculation line or in the exhaust gas line upstream of the exhaust gas recirculation line.

Claims

1-17. (canceled)

18. An exhaust gas conducting system for a gasoline engine, comprising an exhaust gas line which can be connected to an exhaust manifold of the gasoline engine, an inlet line which can be connected to an intake manifold of the gasoline engine, and a turbine which is arranged in the exhaust gas line, wherein at least one exhaust gas recirculation line having an EGR valve is provided which opens into the inlet line, and that the exhaust gas line has at least one bypass line with a bypass choke flap valve, which opens into the exhaust gas line downstream of the turbine, wherein a) the exhaust gas recirculation line branches off upstream of the turbine, and the bypass line branches off to the exhaust gas recirculation line, or b) the bypass line branches off upstream of the turbine, and the exhaust gas recirculation line branches off to the bypass line, wherein c) at least one particle filter is arranged in the exhaust gas recirculation line or in the bypass line upstream of the exhaust gas recirculation line or in the exhaust gas line upstream of the exhaust gas recirculation line, wherein, for the purpose of higher load operation of the gasoline engine, the bypass line and simultaneously the exhaust gas recirculation line can be acted on with exhaust gas, wherein the at least one particle filter has a catalytically acting coating for the conversion of CO, HC and NOx and an exhaust gas catalytic converter configured as 3-way catalytic converter is provided downstream of the turbine.

19. The exhaust gas conducting system according to claim 18, wherein a cooler is provided inside the exhaust gas recirculation line downstream of the particle filter.

20. The exhaust gas conducting system according to claim 19, wherein the cooler has on the outlet side an exhaust gas nominal temperature Ta, which lies above the dewpoint of the substances contained in the exhaust gas.

21. The exhaust gas conducting system according to claim 18, wherein the inlet line upstream of the opening of the exhaust gas recirculation line is configured as a fresh air line, and that at least one fresh air cooler and one fresh air choke flap valve are provided in the fresh air line.

22. The exhaust gas conducting system according to claim 21, wherein the fresh air cooler has on the outlet side a fresh air nominal temperature Tf with 150 C.>=Tf>=60 C.

23. The exhaust gas conducting system according to claim 18, wherein the inlet line downstream of the opening of the exhaust gas recirculation line is configured as a charge-air line, and that at least one charge-air cooler is provided in the charge-air line.

24. The exhaust gas conducting system according to claim 23, wherein the charge-air cooler has on the outlet side a charge-air nominal temperature Tu, with Tu<=60 C.

25. The exhaust gas conducting system according to claim 18, wherein an exhaust gas mass flow can be adjusted inside the exhaust gas recirculation line by means of the EGR valve in the exhaust gas recirculation line, depending on the operation point.

26. The exhaust gas conducting system according to claim 18, wherein an exhaust gas mass flow can be adjusted inside the bypass line by means of the bypass choke flap valve in the bypass line, depending on the operation point.

27. The exhaust gas conducting system according to claim 18, wherein an additional exhaust gas recirculation line having an additional EGR valve is provided, which branches off to the exhaust gas recirculation line or branches off to the bypass line, wherein the additional exhaust gas recirculation line opens into the inlet line upstream of a compressor.

28. The exhaust gas conducting system according to claim 18, wherein a device is provided for introducing secondary air, by means of which secondary air can be introduced into the exhaust gas recirculation line and/or into the bypass line.

29. The exhaust gas system and/or gasoline engine having an exhaust gas conducting system according to claim 18.

30. A method for operating a gasoline engine having an exhaust gas conducting system or an exhaust gas system according to claim 18, wherein a) during the operation of the gasoline engine, with an at least partially open EGR valve, at least a part of the exhaust gas flow is conveyed through the particle filter and through the bypass line, wherein a regeneration of the particle filter takes place; b) during and after the start of the gasoline engine, with the EGR valve at least partially closed, by opening the bypass choke flap valve, at least a part of the exhaust gas flow is conveyed through the particle filter and through the bypass line past the turbine, until a predetermined state requires the closing of the bypass line; c) during the higher load operation of the gasoline engine, or at least close to full load, the bypass line is used as a wastegate for conveying at least a part of the exhaust gas flow past the turbine, wherein a regeneration of the particle filter is carried out.

31. The method according to claim 30, wherein on the introduction of secondary air by the device a) the EGR valve is opened and, optionally, supplementary exhaust gas is conveyed through the bypass line, or b) the EGR valve is closed and, alternatively, exhaust gas is conveyed through the bypass line.

32. The method according to claim 30, wherein the blowing in of secondary air can also be introduced into the EGR line.

33. The method according to claim 31, wherein the blowing in of secondary air can also be introduced into the EGR line.

Description

DRAWINGS

[0063] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0064] Further advantages and details of the disclosure are explained in the claims and in the description and represented in the figures, wherein:

[0065] FIG. 1 shows a principle sketch of an HP-EGR having a bypass line;

[0066] FIG. 2 shows a principle sketch of an MP-EGR having a bypass line;

[0067] FIG. 3 shows a principle sketch of a combined HP and MP-EGR having a bypass line.

[0068] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

[0069] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0070] Represented in all the principle sketches according to FIGS. 1-3 is an exhaust gas conducting system 1 (EGR system), which is integrated into the exhaust gas system and charge-air system of a gasoline engine 2 having an exhaust manifold 2.1 and intake manifold 2.2, and having an exhaust gas turbine 3 and charge-air compressor 4. The exhaust gas system and charge-air system has an exhaust gas line 2.3 which is connected to the exhaust manifold 2.1 of the gasoline engine 2, into which exhaust gas line the turbine 3 is integrated. At the end of the exhaust gas line 2.3, exhaust gas 7 leaves the exhaust gas conducting system 1 and flows into the additional exhaust gas stretch, not shown. In addition, an inlet line 2.4 is provided which is connected to the intake manifold 2.2 of the gasoline engine 2, into which inlet line the compressor 4 is integrated. The inlet line 2.4 is supplied with fresh air 8 by means of an air supply system, not represented. In addition, at least one exhaust gas recirculation line 1.1a (EGR line) having an EGR valve 1.3 is provided, which branches off to the exhaust gas line 2.3, and opens into the inlet line 2.4. Optionally provided downstream of the turbine 3 and upstream of the opening of a bypass line 1.1b, according to FIG. 1, is an exhaust gas flap valve 2.7, by means of which the flow resistance of the exhaust gas turbine 3 can be influenced.

[0071] As a supplement to this, the bypass line 1.1b is provided, which likewise branches off to the exhaust gas line 2.3 and opens downstream of the turbine 3 into the exhaust gas line 2.3. In this situation, it is not of significance whether the bypass line 1.1b branches off to the exhaust gas recirculation line 1.1a or whether the exhaust gas recirculation line 1.1a branches off to the bypass line 1.1b. The bypass line 1.1b has a bypass choke flap valve 1.4 for regulating the gas mass flow.

[0072] Both the EGR valve 1.3 and the bypass choke flap valve 1.4 are arranged downstream of the particle filter 1.2, 1.2x.

[0073] Arranged in the EGR line 1.1a is a particle filter 1.2, 1.2x which filters the exhaust gas 7 which has been recirculated or is to be recirculated. The particle filter 1.2x can be coated, and can fulfil the functions of a 3-way catalytic converter or at least an oxidation catalytic converter. As an alternative, the particle filter 1.2 can also be uncoated. In this case, an exhaust gas catalytic converter 5* may be necessary, which is, for example, placed upstream of the particle filter 1.2 (represented by broken lines), in order to guarantee a catalytic cleaning of the recirculated exhaust gas 7.

[0074] Additionally provided in the EGR line 1.1a downstream of the particle filter 1.2, 1.2x is at least one EGR cooler 1.6. Downstream of the respectively EGR cooler 1.6 or upstream of the opening into the inlet line 2.4 is an EGR valve 1.3 for regulating the mass flow inside the EGR line 1.1a.

[0075] Provided in the inlet line 2.4 is a charge-air or fresh air choke flap valve 2.6, upstream of the introduction point of the exhaust gas recirculation line 1.1a into the inlet line 2.4. This part of the inlet line 2.4 is also referred to as the fresh air line 2.4a. Also provided inside the fresh air line 2.4a is a charge-air or fresh air cooler 6.

[0076] Provided downstream of the turbine 3, in the exhaust gas line 2.3, is a catalytic converter 5 which is configured as a 3-way catalytic converter or as an oxidation catalytic converter. Irrespective of the exemplary embodiments described hereinafter, the catalytic converter 5 used in each case can in principle be a 3-way catalytic converter or an oxidation catalytic converter. An oxidation catalytic converter 5 is considered, in particular, if the gasoline engine 2 is a lean combustion configuration.

[0077] As a supplement to the EGR cooler 1.6 and to the fresh air cooler 6, placed in the inlet line 2.4 downstream of the introduction point of the exhaust gas recirculation line 1.1a is a charge-air cooler 2.5. This part of the inlet line 2.4 downstream of the introduction point of the exhaust gas recirculation line 1.1a is also referred to as the charge-air line 2.4b.

[0078] Additionally provided on the exhaust gas side is a device 9 for introducing secondary air into the cylinder head or into the exhaust manifold 2.1 or into the exhaust gas line 2.3.

[0079] In principle, a distinction is made between three variants of the exhaust gas recirculation, depending on the branching off of the EGR line 1.1a from the exhaust gas line 2.3 and the opening of the EGR line 1.1a into the inlet line 2.4.

[0080] The combination of branching off of the EGR line 1.1a upstream of the turbine 3 and opening of the EGR line 1.1a downstream of the compressor 4 is referred to as high-pressure EGR (HP-EGR).

[0081] The combination of branching off of the EGR line 1.1a upstream of the turbine 3 and opening of the EGR line 1.1a upstream of the compressor 4 is referred to as maximum-pressure EGR (MP-EGR).

[0082] The combination of branching off of the EGR line 1.1a downstream of the turbine 3 and opening upstream of the compressor 4 is referred to as low-pressure EGR (LP-EGR).

[0083] Represented in the diagram according to FIG. 1 is an HP-EGR, formed by the EGR line 1.1a, which branches off upstream of the turbine 3 and opens downstream of the compressor 4. The opening is downstream of the charge-air or fresh air choke flap valve 2.6.

[0084] An MP-EGR is configured in accordance with FIG. 2.

[0085] In the exemplary embodiment according to FIG. 3, an HP-EGR and an MP-EGR are combined. Downstream of the cooler 1.6, an additional EGR line 1.1c having an additional EGR valve 1.5, branches off to the bypass line 1.1b. Provided in the EGR line 1.1c is an additional EGR valve 1.5. The EGR line 1.1c opens into the inlet line 2.4 upstream of the compressor 4. An EGR cooler 1.6* can, as an alternative, also be positioned downstream of the branching off for the additional EGR line 1.1c. The bypass line 1.1b can also open downstream of the catalytic converter 5 (represented by broken lines). This also applies to the exemplary embodiments according to FIG. 1 and FIG. 2.

[0086] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.