EGR SYSTEM WITH PARTICLE FILTER FOR A GASOLINE ENGINE

Abstract

An exhaust gas recirculation system for a gasoline engine, including an exhaust gas line, which can be connected to an exhaust manifold of the gasoline engine and which includes a turbine, and an inlet line, which can be connected to an intake manifold of the gasoline engine and which includes a compressor. A main exhaust gas catalytic converter is provided in the exhaust gas line, and at least one exhaust gas recirculation line_I is provided which branches off from the exhaust gas line upstream of the turbine and opens into the inlet line downstream of the compressor. At least one particle filter_I is provided which is placed in the exhaust gas recirculation line_I or in the exhaust gas line upstream of the exhaust gas recirculation line_I. The particle filter_I has a 3/Ox coating, and at least one cooler_I is provided within the exhaust gas recirculation line_I downstream of the at least one particle filter.

Claims

1. An exhaust gas recirculation system for a gasoline engine, comprising: an exhaust pipe which can be attached to an exhaust manifold of the gasoline engine, with a turbine and with an inlet pipe which can be connected to an inlet manifold of the gasoline engine, with a compressor, wherein at least one exhaust gas recirculation pipe_I is provided, which branches at the exhaust pipe upstream of the turbine and opens in the inlet pipe downstream of the compressor, wherein at least one particle filter_I is provided, which is located in the exhaust gas recirculation pipe_I or in the exhaust pipe upstream of the exhaust gas recirculation pipe_I, wherein the particle filter_I has a 3/Ox-coating, and that, downstream of the at least one particle filter, at least one cooler_I is provided inside the exhaust gas recirculation pipe_I.

2. An exhaust gas recirculation system for a gasoline engine, comprising: an exhaust pipe which can be connected to an exhaust manifold of the gasoline engine, and with an inlet pipe which can be connected to an inlet manifold of the gasoline engine, wherein, in the exhaust pipe, a main exhaust gas catalytic converter is located and at least one exhaust gas recirculation pipe_II is provided, which branches at the exhaust pipe and opens into the inlet pipe, wherein at least one particle filter_II is provided, which is located in the exhaust gas recirculation pipe_II, or that at least one particle filter_II is provided, which is located in the exhaust pipe upstream of the exhaust gas recirculation pipe_II, wherein the exhaust gas recirculation pipe_II branches upstream or downstream of the exhaust gas catalytic converter, wherein, with branching upstream of the exhaust gas catalytic converter, the particle filter_II has a 3/Ox-coating, or, with branching downstream of the exhaust gas catalytic converter, an additional particle filter is located in the exhaust gas recirculation pipe_II, and that, downstream of the particle filter, at least one cooler_II is provided inside the exhaust gas recirculation pipe_II.

3. The exhaust gas recirculation system according to claim 2, wherein provided in the exhaust pipe is a turbine and in the inlet pipe is a compressor, wherein the exhaust gas recirculation pipe_II branches at the exhaust pipe downstream of the turbine and opens in the inlet pipe upstream of the compressor.

4. The exhaust gas recirculation system according to claim 1, wherein provided in the exhaust pipe is a turbine and in the inlet pipe is a compressor, wherein the exhaust gas recirculation pipe_II branches at the exhaust pipe downstream of the turbine and opens in the inlet pipe upstream of the compressor.

5. The exhaust gas recirculation system according to claim 1, wherein the particle filter_I which is located in the exhaust gas recirculation pipe_I, is free of an 3/Ox-coating, and located upstream of the first particle filter is an additional exhaust gas catalytic converter inside the exhaust gas recirculation pipe_I.

6. The exhaust gas recirculation system according to claim 2, wherein the particle filter_II, which is located downstream of the exhaust gas catalytic converter in the exhaust gas recirculation pipe_II, has a 3/Ox-coating or is free of a 3/Ox-coating.

7. The exhaust gas recirculation system according to claim 1, wherein the cooler_I inside the exhaust gas recirculation pipe_I and/or a charge-air cooler is configured as an exhaust gas engine cooling water cooler or as an exhaust gas low-temperature cooling water cooler, and is at least thermally separated from the particle filter.

8. The exhaust gas recirculation system according to claim 1, wherein at least one further exhaust gas recirculation pipe is provided, which branches at the exhaust gas recirculation pipe and opens into the inlet pipe, wherein, in at least one of the further exhaust gas recirculation pipes, at least one further cooler is provided.

9. The exhaust gas recirculation system according to claim 7, wherein the further exhaust gas recirculation pipe branches downstream of the first particle filter of the exhaust gas recirculation pipe_I.

10. The exhaust gas recirculation system according to claim 1, wherein the cooler_I exhibits on the outlet side an exhaust gas reference temperature Ta, which lies above the dew point of the substances contained in the exhaust gas.

11. The exhaust gas recirculation system according to claim 1, wherein the at least one further exhaust gas recirculation pipe opens in the inlet pipe upstream of the compressor or downstream of the compressor.

12. The exhaust gas recirculation system according to claim 1, wherein arranged in the inlet pipe are two compressors, wherein the at least one further exhaust gas recirculation pipe opens between the two compressors.

13. The exhaust gas recirculation system according to claim 1, wherein arranged in the inlet pipe are two compressors and at least two further exhaust gas recirculation pipes, which are connected in parallel by way of a common distribution pipe, branching at the exhaust gas recirculation pipe_I, wherein at least one further exhaust gas recirculation pipe opens upstream of at least one of the compressors, and/or at least one further exhaust gas recirculation pipe opens downstream of at least one of the compressors.

14. The exhaust gas recirculation system according to claim 1, wherein a charge-air cooler and/or a charge-air choke valve are provided in the inlet pipe, wherein the opening of the exhaust gas recirculation pipe_I is located downstream of a position for the charge-air cooler and/or downstream of a position for the charge-air choke valve, or upstream of a position for the charge-air cooler and downstream of a position for the charge-air choke valve.

15. The exhaust gas recirculation system according to claim 13, wherein as a supplement to the charge-air cooler, a fresh-air cooler is located in the inlet pipe, wherein the fresh-air cooler is located upstream of the opening of the exhaust gas recirculation pipe.

16. The exhaust gas recirculation system according to claim 14, wherein the fresh-air cooler exhibits on the outlet side a fresh air reference temperature Tf with 150° C.>=Tf>=90° C. and the charge-air cooler exhibits on the outlet side a charge-air reference temperature Tu, with 30° C.<=Tu<=40° C.

17. The exhaust gas recirculation system according to claim 8, wherein a charge-air cooler is provided in the inlet pipe, wherein the opening of at least one further exhaust gas recirculation pipe is located upstream of a position for the charge-air cooler.

18. The exhaust gas recirculation system according to claim 1, wherein a choke valve is provided in the exhaust gas recirculation pipe_I and/or in the exhaust gas recirculation pipe_II, by which, depending on the operating point, an exhaust gas mass flow is adjustable inside the exhaust gas recirculation pipe, wherein the choke valve a) is located downstream of the particle filters or b) is located downstream or upstream of the cooler.

19. The exhaust gas recirculation system according to claim 7, wherein in each case a further cooler is provided inside the respective further exhaust gas recirculation pipe, or that in each case a further cooler is located in the distribution pipe upstream of the respective further exhaust gas recirculation pipe.

20. The exhaust gas recirculation system according to claim 1, wherein the exhaust pipe has two parallel exhaust pipe sections which can be switched by means of an adjustable valve, wherein the exhaust gas catalytic converter is located in the exhaust pipe section, and in the parallel exhaust pipe section the particle filter is located, as well as the branch for the exhaust gas recirculation pipe_11.

21. The exhaust gas recirculation system according to claim 7, wherein the exhaust gas recirculation pipe_II and the further exhaust gas recirculation pipe are coupled by means of an adjustable valve, wherein downstream of the valve a cooler is provided and/or downstream of the cooler a choke valve is provided.

22. The exhaust gas recirculation system according to claim 7, wherein in the respective further exhaust gas recirculation pipe a choke valve is provided, wherein the choke valve is optionally located downstream of the further cooler.

23. The exhaust gas recirculation system according to claim 1, wherein downstream of the main exhaust gas catalytic converter, a main particle filter is provided, which is free of a catalytically effective coating for the conversion of CO, HC and/or NOx.

24. The exhaust gas recirculation system according to claim 1, wherein the exhaust gas recirculation pipe_I is allocated to one single cylinder outlet of the gasoline engines.

25. The exhaust gas recirculation system according to claim 1, wherein the turbine is configured as a VTG turbine.

26. The gasoline engine or exhaust gas system for a gasoline engine, with the exhaust gas recirculation system according to claim 1.

27. The gasoline engine according to claim 26, with a displacement exhibiting a volume Vh and with a compression volume Vk, wherein a compression ratio Vv=(Vh+Vk)/Vk is applied, with 15:1<=Vv<=10:1.

28. The gasoline engine according to claim 26, wherein the particle filter exhibits a total volume Vf, wherein for the total volume Vf the following applies: 0.1 Vh<=Vf<=1 Vh or 0.1 Vh<=Vf<=0.5 Vh or that a plurality of particle filters are provided, which together have the total volume Vf.

29. A method for the operation of a gasoline engine according to claim 26, wherein the exhaust gas recirculation rate during operation, at least for an HP-EGR and at least in a high-load range and at full load, is raised to a value of up to 20%, up to 30%, up to 40% or up to 50% and/or by early ignition angle adjustment, a combustion center of gravity is brought closer to the thermodynamically optimum value of 8° crank angle and/or a fuel quantity to be delivered to the gasoline engine is reduced and a full-load enrichment is avoided.

30. The method according to claim 29, wherein at least one of the method steps is repeated at least once.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0088] Further advantages and details of the invention are explained in the claims and in the description, and represented in the figures. The figures show:

[0089] FIG. 1 a principle sketch of a combinable HP and LP-EGR;

[0090] FIG. 2 a principle sketch of an MP-EGR;

[0091] FIGS. 3a, 3b principle sketches of a combined HP and MP-EGR, with different cooler arrangements and inlets into the inlet pipe;

[0092] FIGS. 4a, 4b principle sketches of a combined HP, MP and LP-EGR, with different cooler arrangements and inlets into the inlet pipe;

[0093] FIGS. 5a, 5b principle sketches of a partial HP or MP-EGR, with which the entire exhaust gas of a cylinder is being recirculated;

[0094] FIGS. 6a-6c partial representation of the different architectures from FIG. 1;

[0095] FIG. 7 a principle sketch of the HP-EGR according to FIG. 1 with charge-air and fresh-air cooler.

DETAILED DESCRIPTION OF THE INVENTION

[0096] In all the principle sketches according to FIGS. 1-6, an exhaust gas recirculation system 1 (EGR system) is represented which is integrated into the exhaust gas and charge-air system of a gasoline engine 2 exhibiting a displacement 2.4 with exhaust manifold 2.1 and inlet manifold 2.2, as well as an exhaust gas turbine 3 and charge-air compressor 4. The exhaust gas and charge-air system has an exhaust pipe 1.1, attached to the exhaust manifold 2.1 of the gasoline engine 2, into which the turbine 3 is integrated. At the end of the exhaust pipe 1.1, exhaust gas 8 leaves the exhaust gas recirculation system 1 and flows into the further exhaust gas stretch, not shown. Also provided is an inlet pipe 1.2, connected to the inlet manifold 2.2 of the gasoline engine 2, into which the compressor 4 is integrated. The inlet pipe 1.2 is provided with fresh air 7 via an air delivery system, not shown. As a supplement, at least one exhaust gas recirculation pipe 1.3, 1.3a, 1.3b (EGR pipe) is provided, which branches off at the exhaust pipe 1.1 and opens into the inlet pipe 1.2.

[0097] Arranged either in the EGR pipe 1.3, 1.3a, 1.3b is a particle filter 1.4x, 1.4ax, or alternatively (represented by broken lines), in the exhaust pipe 1.1 upstream of the EGR pipe 1.3, a main particle filter 1.4x′ is arranged, which filters the recirculated or recirculating exhaust gas 8. The respective particle filter 1.4x, 1.4ax, 1.4x′ is provided with a 3-way catalytic converter coating for the oxidation of HC and CO or the reduction of NOx, in order to fulfil the 3-way catalytic converter function. At least one HC oxidation coating is provided for the oxidation of HC and CO. This also applies to all the particle filters referred to hereinafter. Both variants of the coating are referred to collectively hereinafter under the designation of 3/Ox-coating.

[0098] In addition, in the respective EGR pipe 1.3, 1.3a downstream of the particle filter 1.4x, 1.4ax at least one EGR cooler 1.7, 1.7*, 1.7a is provided. Located downstream of the respective EGR cooler 1.7, 1.7a, 1.7b, or upstream of the opening into the inlet pipe 1.2 is an EGR choke valve 1.8, 1.8a, 1.8b, for regulating the mass flow inside the EGR pipe 1.3, 1.3a.

[0099] In principle, a distinction is made between three architectures of the exhaust gas recirculation system, depending on the branching of the EGR pipe from the exhaust pipe 1.1 and the opening of the EGR pipe into the inlet pipe 1.2.

[0100] The combination of branching of the EGR pipe_I 1.3 upstream of the turbine 3 and the opening of the EGR pipe_I 1.3 downstream of the compressor 4 is designated as high-pressure EGR (HP-EGR).

[0101] The combination of branching of the EGR pipe I_1.3 upstream of the turbine 3 and opening of the EGR pipe_I 1.3 upstream of the compressor 4 is designated as maximum pressure EGR (MP-EGR).

[0102] The combination of branching of the EGR pipe_II 1.3a downstream of the turbine 3 and opening upstream of the compressor 4 is designated as low-pressure EGR (LP-EGR). The three EGR architectures designated heretofore can be used individually or combined with one another.

[0103] For the further influencing of the recirculated exhaust gas quantity, a choke valve can be installed in the inlet pipe 1.2 upstream of the inlet point of the exhaust gas recirculation pipe_I 1.3 into the inlet pipe 1.2.

[0104] In the arrangement shown according to FIG. 1 different EGR architectures are represented as supplementing or alternative to one another. Provided inside the inlet pipe 1.2, downstream of the compressor 4 and upstream of the opening of the EGR pipe 1.3 are a charge-air cooler 5 and a charge-air choke valve 6.

[0105] There is an HP-EGR, formed by the EGR pipe_I 1.3, which branches upstream of the turbine 3 and opens downstream of the compressor 4 into the inlet pipe 1.2.

[0106] The opening of the charge-air choke valve 6 takes place downstream. Alternatively, the EGR pipe_I 1.3* opens upstream of the charge-air choke valve 6 and upstream of the charge-air cooler 5. In this case, the charge-air choke valve 6* is likewise located upstream of the opening of the EGR pipe_I 1.3*.

[0107] In the inlet pipe 1.2, as a rule, fresh air 7 is conveyed as far as the opening of the EGR pipe_I 1.3. The charge air is composed of the fresh air 7 and the recirculated exhaust gas 8. The particle filter can alternatively, as a main particle filter 1.4x′ according to FIG. 1 (shown as broken lines), also be located in the exhaust pipe 1.1 upstream of the EGR pipe_I 1.3, such that it supplies the main exhaust pipe 1.1.

[0108] Downstream of the turbine 3, provided in the exhaust pipe 1.1 is a main exhaust gas catalytic converter 1.6′, which is configured as a 3-way catalytic converter. Irrespective of the exemplary embodiments described hereinafter, the catalytic converter 1.6′ used in each case can in principle be a 3-way catalytic converter. A pure oxidation catalytic converter 1.6 comes into consideration in particular if the gasoline engine 2 concerned is a lean combustion engine.

[0109] Downstream of the catalytic converter 1.6′, additionally or alternatively, an EGR pipe_II 1.3a branches off, which opens upstream of the compressor 4 and forms an LP-EGR. Provided inside this are the particle filter_II 1.4a and the EGR cooler_II 1.7a and an EGR choke valve 1.8a. In principle, the choke valve 1.8a* can also be provided upstream of the cooler_II 1.7a.

[0110] As an alternative to this, the EGR pipe_II 1.3a* can branch off upstream of the catalytic converter 1.6′. In this case, the particle filter_II 1.4ax with the 3/Ox-coating is involved, concomitantly a 3-way or HC oxidation catalytic converter coating, in order to compensate for the circumventing of the catalytic converter 1.6′. It is also to be noted here that, irrespective of the exemplary embodiments described hereinafter, the coating used in each case for the particle filter_II 1.4x, 14ax can in principle be a 3/Ox-coating.

[0111] As a supplement (represented by broken lines), a main particle filter 1.4′ can be located in the exhaust pipe 1.1 downstream of the EGR pipe_II 1.3a. In this situation, the porosity of the main particle filter 1.4′ can be greater than that of the particle filter 1.4ax in the EGR pipe_II 1.3a. Accordingly, the filtering capacity of the particle filter II 1.4ax is greater than that of the main particle filter 1.4′.

[0112] As an alternative A1 to this LP-EGR described heretofore, the catalytic converter 1.6′ and downstream the main particle filter_I 1.4′ are provided in the main exhaust gas pipe 1.1, wherein the EGR pipe_II 1.3a first branches off downstream of the main particle filter 1.4′. In the EGR pipe_II 1.3a, in addition to the EGR cooler_II 1.7a and the EGR choke valve 1.8a, an additional particle filter 1.4ax* is arranged. This ensures the most complete purification possible of the recirculated exhaust gas, in order to protect the cooler_II 1.7a. Here too, the porosity of the main particle filter 1.4′ can be greater than that of the particle filter_II 1.4ax in the EGR pipe_II 1.3a. Accordingly, the filtering capacity of the particle filter_II 1.4ax is greater than that of the main particle filter 1.4′.

[0113] As a further alternative A2 to the LP-EGR, the exhaust pipe 1.1 is provided with two parallel arranged exhaust pipe sections 1.1a, 1.1b, which can be switched by means of a controllable valve 1.9. Located in the exhaust pipe section 1.1a is a main exhaust gas catalytic converter 1.6′. Arranged in the parallel exhaust gas pipe section 1.1b are the coated particle filter_II 1.4ax and the branch for the EGR pipe_II 1.3a. Accordingly, a switchable bypass is provided for the EGR pipe_II 1.3a, wherein in both cases the 3-way catalyzation, or at least the HC oxidation catalyzation, is attained in the exhaust pipes 1.1a, 1.1b.

[0114] The adjustable valve 1.9 can also be configured in such a way that exhaust gas part quantities of different quantities can flow simultaneously through the parallel exhaust pipe sections 1.1a, 1.1 b.

[0115] As a further alternative, in the exhaust pipe section 1.1b, a non-coated particle filter_II 1.4a can also be used (not represented). In this case, however, the main exhaust gas catalytic converter 1.6* (represented by broken lines) is located in the exhaust pipe 1.1 upstream of the division into the two exhaust pipe sections 1.1a, 1.1b, in order to ensure, in every position of the valve 1.9, a catalytic purification of the exhaust gas 8. In this case, in addition, a coated particle filter_II 1.4ax* would be provided in the in EGR pipe_II 1.3a (represented by broken lines), in order to ensure the purification of the exhaust gas in the EGR pipe_II 1.3a.

[0116] The HP-EGR described in FIG. 1 on the one hand, and the various different LP-EGR architectures which can be used individually or in combination, are once again represented in FIGS. 6a, 6b, 6c separated according to HP and LP. The alternative embodiment, contained in the LP-EGR, of the EGR pipe_II 1.3*, which branches upstream of the catalytic converter 1.6′, is represented by itself in FIG. 6c. The variant of the downstream main particle filters 1.4′ in the main exhaust pipe 1.1 is likewise contained therein.

[0117] FIG. 2 shows a configuration of an MP-EGR. The particle filter_II.4x located in the EGR pipe_I 1.3 exhibits a catalytic converter coating. Provided as a supplement to this in the exhaust pipe 1.1, downstream of the turbine 3, is a main exhaust gas catalytic converter 1.6′, preferably a 3-way catalytic converter. The choke valve 1.8 is located downstream of the cooler_I 1.7. The choke valve 1.8* can, as an alternative, also be provided downstream of the particle filter_I 1.4x. As a supplement to this, provided in the exhaust pipe 1.1 downstream of the main exhaust gas catalytic converter 1.6′ is a non-coated main particle filter 1.4′.

[0118] According to the embodiment in FIG. 3a, starting from the EGR pipe_I 1.3, which branches at the exhaust pipe 1.1, the exhaust gas recirculation continues via further parallel arranged EGR pipes 1.3b-1.3d. Arranged in the EGR pipe_I 1.3 are the particle filter_I 1.4x with the catalytic converter coating, and the cooler_I 1.7. The EGR pipes 1.3b-3d in each case branch off at a distribution pipe 13, which in turn branches at the EGR pipe_I 1.3 downstream of the cooler_I 1.7. All the EGR pipes 1.3-1.3d open at the inlet pipe 1.2. Each of these EGR pipes 1.3-1.3d has downstream of the distribution pipe 13 a choke valve 1.8-1.8d, wherein all the choke valves 1.8-1.8d are connected via a control line 9.1 to a control unit 9 for controlling or regulating the position of the respective choke valve 1.8-1.8d, and can be individually controlled. Provided downstream of the respective choke valve 1.8-1.8d, in the respective EGR pipe 1.3-1.3d, is an additional or further cooler 1.7*, 1.7b-1.7d. The inlet pipe 1.2 exhibits two compressors 4a, 4b, which in each case are coupled to a turbine 3a, 3b of the exhaust pipe 1.1. The EGR pipes 1.3, 1.3b both open downstream of the compressor 4a and form an HP-EGR. The EGR pipe 1.3b opens upstream of the charge-air cooler 5, while the EGR pipe_I 1.3 opens downstream of the charge-air cooler 5.

[0119] The EGR pipe 1.3d opens upstream of the compressor 4b and forms an MP-EGR. The EGR pipe 1.3c, however, opens between the two compressors 4a, 4b, and therefore forms a reduced MP-EGR.

[0120] With regard to the embodiment in FIG. 3a, one of the two EGR coolers 1.7, 1.7* in the EGR pipe_I 1.3 can optionally be omitted (not represented).

[0121] Located downstream of the turbines 3a, 3b is a 3-way catalytic converter (main exhaust gas catalytic converter) 1.6′, starting from which the exhaust gas 8 or the main gas flow is conveyed into the further exhaust gas system. As a supplement to this, located in the exhaust pipe 1.1, downstream of the main exhaust gas catalytic converter 1.6′, is a non-coated main particle filter 1.4′.

[0122] The exemplary embodiment according to FIG. 3b is configured in a similar manner. In this situation, a cooler_I 1.7 is provided in the EGR pipe_I 1.3, upstream of the branching of the distribution pipe 13, and three further coolers 1.7b-1.7d are located in the distribution pipe 13, in each case upstream of the branching of the respective EGR pipe 1.3b-1.3d. Accordingly, the additional cooler 1.7* is no longer necessary, as the case is with the exemplary embodiment according to FIG. 3a.

[0123] Both exemplary embodiments according to FIGS. 3a and 3b ensure an extremely flexible EGR arrangement, such that an extensive particle filtering and a regeneration of the particle filter_I 1.4x on the one hand, and, on the other, the delivery to meet the requirement of cooled exhaust gas 8 into the inlet pipe 1.2 for a full operational range of the engine, are ensured at all times.

[0124] The exemplary embodiments according to FIGS. 4a, 4b has an HP-EGR, an MP-EGR, and an LP-EGR. Located in the inlet pipe 1.2 are the charge-air cooler 5 and the charge-air-choke valve 6, while the exhaust pipe 1.1 downstream of the turbine 3 is fitted with a 3-way catalytic converter 1.6′ and a downstream particle filter 1.4a.

[0125] According to the exemplary embodiment in FIG. 4a, provided in the EGR pipe_I 1.3 is first of all a coated particle filter_I 1.4x. Following this, a further EGR pipe 1.3b branches off. While the EGR pipe_I 1.3 as an HP-EGR opens downstream of the charge-air choke valve 6 at the exhaust pipe 1.1, the further EGR pipe 1.3b, as an MP-EGR, opens upstream of the compressor 4. Provided in the EGR pipe_I 1.3, downstream of the further EGR pipe 1.3b are the cooler_I 1.7 and a downstream choke valve 1.8. Provided in the further EGR pipe 1.3b are likewise a further cooler 1.7b and a downstream choke valve 1.8b.

[0126] As a supplement to this, a second EGR pipe_II 1.3a is provided, which branches downstream of the main exhaust gas catalytic converter 1.6′ and downstream of the main particle filters 1.4′, and concomitantly downstream of the turbine 3, at the exhaust pipe 1.1. It likewise has a cooler_II 1.7a and a downstream choke valve 1.8a, before it opens at the inlet pipe 1.2 upstream of the compressor 4, and therefore represents an LP-EGR. As a supplement or alternative (represented by broken lines), the particle filter_II 1.4a can be located in the EGR pipe_II 1.3a.

[0127] Both the HP-EGR as well as the MP-EGR and the LP-EGR can be realized in any combination.

[0128] As a departure from the exemplary embodiment according to FIG. 4a, in the exemplary embodiment according to FIG. 4b the further EGR pipe 1.3b and the EGR pipe_II 1.3a are coupled via an adjustable valve 1.9. This has the advantage that a cooler 1.7a/b and a choke valve 1.8a/b are less necessary. However, in addition or as an alternative to the HP-EGR, only the MP-EGR or the LP-EGR are realized. In addition, the particle filter_I 1.4 in the EGR pipe_I 1.3 is non-coated, such that an additional exhaust gas catalytic converter 1.6 is provided upstream. This possibility always pertains as an alternative to the coated particle filter.

[0129] With the exemplary embodiments according to FIGS. 5a and 5b, the EGR pipe_I 1.3 is allocated to one single cylinder outlet 2.3 of the gasoline engine 2, and conveys the exhaust gas quantity of this cylinder outlet 2.3. Located in the inlet pipe 1.2 are the charge-air cooler 5 and the charge-air choke valve 6, while the exhaust pipe 1.1 downstream of the turbine 3 is fitted with a 3-way catalytic converter 1.6′ and a downstream main particle filter 1.4′.

[0130] An HP-EGR is configured according to the exemplary embodiment in FIG. 5a. The EGR pipe_I 1.3 has a coated particle filter_I 1.4x and a downstream cooler_I 1.7 as well as, located downstream of the cooler_I 1.7, a choke valve 1.8.

[0131] In one exemplary embodiment which is not shown, a non-coated particle filter_I 1.4 can also be provided in combination with a 3/Ox-catalytic converter in the EGR pipe_I 1.3.

[0132] According to the exemplary embodiment in FIG. 5b, an MP-EGR is supplemented. For this purpose, a further EGR pipe 1.3b branches off between the coated particle filter_I 1.4x and the cooler_I 1.7, which opens upstream of the compressors 4. Located in this further EGR pipe 1.3b are likewise a further cooler 1.7b and a downstream choke valve 1.8b. In an exemplary embodiment not shown, a non-coated particle filter 1.4 can also be provided in combination with a 3/Ox-catalytic converter in the EGR pipe_I 1.3.

[0133] The exemplary embodiment according to FIG. 7 corresponds essentially, up to the position of the charge-air choke valve 6, to the HP-EGR architecture according to FIG. 1 alone. Two coolers are provided in the inlet pipe 1.2, however. A charge-air cooler is located 5.1 downstream of the opening of the EGR pipe_I 1.3, and a second cooler, referred to as a fresh-air cooler 5.2, is located upstream of the opening of the EGR pipe_I 1.3. In the downstream charge-air cooler 5.1, the compressed, and, if appropriate, pre-cooled fresh air 7, together with the recirculated and pre-cooled exhaust gas 8, are lowered to the desired charge-air temperature of preferably 30° C. to 40° C. The turbine 3 is a VTG turbine in a design and with material properties such as are usual with diesel engines. The particle filter_I 1.4x is configured as coated.