EGR system with particulate filter for gasoline engine

Abstract

Exhaust gas recirculation system (1) for a gasoline engine (2) comprising the following: an exhaust pipe (1.1) that can be connected to an exhaust manifold (2.1) of the gasoline engine (2), an intake manifold (2.2) of the Otto engine (2) that can be connected to an intake manifold (2.2), a 3-way main exhaust catalyst (1.6a, 1.6') in the exhaust pipe (1.1), at least one first exhaust gas recirculation line (1.3) branching off from the exhaust pipe (1.1) and opening into the intake pipe (1.2), at least one second exhaust gas recirculation line (1.3a) branching off from the exhaust pipe (1.1) and opening into the intake pipe (1.2), at least one particulate filter (1.4x) which: - is located in the first exhaust gas recirculation line (1.3), and at least one further particulate filter (1.4ax) which: - is located in the second exhaust gas recirculation line (1.3a), and / or - is located in the exhaust pipe (1.1) upstream of the second exhaust gas recirculation pipe (1.3a), wherein the at least one particle filter (1.4x) and the at least one further particle filter (1.4ax) have a catalytically active coating for the conversion of CO, HC and NOx.

Description

[0001] The invention relates to an exhaust gas recirculation (EGR) system for a gasoline engine, comprising an exhaust pipe connectable to an exhaust manifold and an intake pipe for charge air or combustion air connectable to an intake manifold. A three-way main exhaust catalyst is provided in the exhaust pipe. In the case of a turbocharged engine, a compressor can be arranged in the intake pipe, which, in the case of a turbocharged engine, is connected to a turbine located in the exhaust pipe. The compressor can also be driven alternatively.

[0002] The term "Otto engine" encompasses all non-diesel engines, including all spark-ignition engines, SI (Spark Ignited) engines with spark plugs, and at least partially compression-ignition engines, CAI (Controlled Auto Ignition) engines, which run on gasoline, alcohol, or gas. Diesel engines, in contrast, are compression-ignition engines, HCCI (Homogeneous Charge Compression Ignition) engines, which run on diesel, oils, or other fuels.

[0003] Exhaust gas recirculation systems are known from DE 10 2009 046 016 A1, DE 10 2009 022 938 A1, WO 2014 / 022 208 A1, DE 10 2006 057 488 A1, FR 2 894 624 A1 and DE 103 49 129 A1.

[0004] Exhaust gas recirculation systems for diesel engines are known from DE 10 2010 063 444 A1, DE 10 2013 213 103 A1 and DE 10 2012 022 154 A1.

[0005] Furthermore, DE 10 2009 051 027 A1 shows a drive unit with a diesel internal combustion engine and exhaust gas recirculation as well as a method for operating such a drive unit.

[0006] A diesel exhaust gas recirculation (EGR) system for diesel engines is disclosed in US Patent 5,671,600 A. A particulate filter is provided at the exhaust outlet or exhaust pipe, to which an EGR line is connected. The EGR line terminates in the intake pipe upstream of an intercooler. A valve for modifying the exhaust gas mass flow is provided within the EGR line. The particulate filter serves to protect the intercooler and / or the charge air cooler from contamination.

[0007] DE 10 2011 015 629 A1 describes the use of a three-way catalytic converter within an exhaust gas recirculation line of a gasoline engine to improve pollutant emissions, thus reducing HC, NOx and CO.

[0008] From EP 2 194 351 B1 an intercooler with an integrated diesel particle filter to protect the intercharge air compressor is known.

[0009] DE 10 2012 107 649 B4 describes a particulate filter in the exhaust line upstream of an exhaust gas recirculation line for supplying a pressure wave supercharger, as is known to the applicant for diesel engines.

[0010] The present invention is aimed at overcoming one or more of the problems or disadvantages associated with the prior art.

[0011] The object of the present invention is achieved by an exhaust gas recirculation system, an exhaust system, and a gasoline engine according to the main claims. The dependent claims relate to preferred embodiments of the invention. The invention is based in particular on the objective of designing and arranging an EGR system for a gasoline engine in such a way as to achieve reduced soiling of components in the intake system and improved combustion, thereby enabling increased operational reliability and, in addition to reduced pollutant emissions, improved engine efficiency.

[0012] An EGR system typically consists of at least an exhaust gas recirculation line (EGR line), an optional exhaust gas recirculation cooler (EGR cooler) and an exhaust gas recirculation flap (EGR flap).

[0013] The problem is solved according to the invention by the fact that at least one first exhaust gas recirculation (EGR) line is provided, branching off from the exhaust pipe and opening into the intake pipe, wherein at least one particulate filter is arranged in the exhaust gas recirculation line and optionally a turbine is provided in the exhaust pipe, wherein at least one second exhaust gas recirculation line is provided, branching off from the exhaust pipe and opening into the intake pipe, wherein at least one further particulate filter is provided, - which is located in the second exhaust gas recirculation line and / or - which is located in the exhaust pipe upstream of the second exhaust gas recirculation pipe.

[0014] The second exhaust gas recirculation (EGR) line only has a different technical effect than the first if a turbine is integrated into the exhaust system. In this case, the second EGR line branches off downstream of the turbine, while the first EGR line branches off upstream. This allows for the use of various EGR architectures defined below, such as high-pressure EGR (HP-EGR) or low-pressure EGR (LP-EGR), either as a supplement to or alternative to the first or second EGR line.

[0015] The problem is therefore solved by the inventive combination of three features, namely that x) at least one first EGR line is provided, which branches off from the exhaust gas line and leads into the intake line, wherein a particulate filter is arranged in the exhaust gas recirculation line; y) optionally a turbine is provided in the exhaust pipe; z) at least one second exhaust gas recirculation line is provided, branching off from the exhaust line and leading into the intake line, and at least one particulate filter is provided, - which is located in the second exhaust gas recirculation line and / or - which is located in the exhaust pipe upstream of the second exhaust gas recirculation pipe, whereby feature x) alone or one of the feature combinations x) + y) or y) + z) or x) + y) + z) is to be applied. Feature z) alone corresponds to feature x) alone due to the absence of a turbine.

[0016] Regarding the second exhaust gas recirculation line, at least one particulate filter can be placed in the exhaust line between the first exhaust gas recirculation line and the second exhaust gas recirculation line.

[0017] The first exhaust gas recirculation line can also connect to the exhaust manifold and / or terminate at the intake manifold. If a compressor is present, the second exhaust gas recirculation line typically terminates before the compressor.

[0018] A particulate filter is specifically designed to retain particles larger than 25-15 nm, and especially those larger than 10 nm. Ideally, the retained particle size could be even smaller.

[0019] Deposits known as "wet soot" or "fouling" can be observed in the EGR system and intake system of gasoline engines. These deposits can have serious consequences such as reduced cooling performance, blockages, poor fuel distribution, and irregular combustion. Therefore, EGR systems are currently used only rarely and with limitations in gasoline engines.

[0020] In EGR systems for gasoline engines, cooling the recirculated exhaust gas is advantageous for optimizing combustion, as recirculating uncooled exhaust gases, especially at higher loads and full load, leads to higher intake air temperatures due to the added hot exhaust gases. This, in turn, results in cylinder filling losses and an increased tendency for the gasoline engine to knock. Consequently, undesirable engine power losses are also a consequence. These disadvantages can be reduced by cooling the recirculated exhaust gas. However, this results in the formation of an increased amount of condensate – consisting of water and / or hydrocarbons or hydrocarbon compounds and incompletely combusted combustion residues – in the recirculated exhaust gas, leading to an increased degree of sooting in the form of wet, adhesive deposits in the EGR and intake air systems.A combination of the particulate filter with the charge air cooler, as described in EP 2 194 351 B1 for a diesel particulate filter, is therefore not an option in order to avoid the risk of clogging due to the previously described deposits in the particulate filter.

[0021] Furthermore, a particulate filter only reaches the minimum temperature required for self-regeneration within a significantly limited operating range. In this case, additional active regeneration measures are necessary, which are disadvantageous in terms of operation and cost. In contrast to the wet components carried in gasoline exhaust, diesel particulates are drier and exhibit a lower tendency to condense and clump. Moreover, due to the lower exhaust gas temperatures in diesel engines, active regeneration measures for the particulate filter are generally required across a very wide range of engine operating conditions.

[0022] Like diesel particulate filters, particulate filters for gasoline engines trap particles. Sufficiently high exhaust gas temperatures and excess oxygen are required for the regeneration of the particulate filter, i.e., for the combustion of filtered particles. After a warm-up phase, these conditions are met by the exhaust gas properties in the EGR systems of gasoline engines. However, in large operating ranges of the gasoline engine, i.e., in the firing state (lambda = 1 for stoichiometrically operated gasoline engines), there is a lack of excess oxygen to fuel the combustion of the particles in the particulate filter. Therefore, the exhaust gas flow merely feeds particles into the particulate filter, where some are burned with the available residual oxygen and the rest are retained until sufficiently favorable combustion conditions are present for complete combustion.Regeneration, and thus combustion of the particles, can occur in engine operating conditions where sufficient oxygen is available in the exhaust gas for combustion of the particles in the GPF (Gasoline Particle Filter), for example, during engine overrun phases when fuel injection is switched off. During this overrun phase, i.e., with the engine still running and the intake and exhaust valves still operating, oxygen enters the EGR system through the open EGR valve and flows through the integrated particulate filter. At a sufficient temperature in the particulate filter, the particles are then burned to CO2. CO, HC, and NOx may also be produced.

[0023] Notwithstanding this cleaning step, the aforementioned advantages of using recirculated exhaust gas in a gasoline engine only become more pronounced when the exhaust gas is cooled closer to the level of the intake, possibly compressed, and recooled fresh air. If such a filter is then used in the exhaust gas recirculation line, this not only protects the intake air system from sooting caused by particles and other substances carried in the exhaust gas, but also enables the widespread use of an exhaust gas cooler within the EGR line to prevent cylinder filling losses, increased knocking tendency, and the associated power losses.

[0024] The external EGR system according to the invention for the gasoline engine ensures a reduction of particles in the recirculated exhaust gas, which allows for greater cooling of the recirculated exhaust gas, especially at higher engine loads and engine speeds, and thus reduces fuel consumption.

[0025] In contrast, an EGR system is used in diesel engines to reduce NOx emissions, particularly in wide partial load ranges or at low engine speeds. However, due to the combustion process in diesel engines, the use of an EGR system inevitably leads to an increase in soot particle emissions and higher fuel consumption.

[0026] Purified, recirculated exhaust gas results in less contamination of components in the exhaust gas recirculation and intake system, as well as improved combustion, which enables increased operational reliability and, in addition to reduced pollutant emissions, also improved engine efficiency.

[0027] It is obvious that the advantages and disadvantages known for diesel engines and the operating principles to be considered when using an EGR system are by no means transferable to gasoline engines.

[0028] It can also be advantageous if the second exhaust gas recirculation line branches off upstream or downstream of the catalytic converter, with a coated particulate filter being provided in the case of an upstream branch. In the case of a downstream branch, the cleaning is carried out by the catalytic converter itself.

[0029] For this purpose, it may be advantageous to provide an exhaust gas catalyst such as an oxidation catalyst or a 3-way catalyst upstream of the particulate filter, with the catalyst being placed inside the exhaust gas recirculation line or inside the exhaust gas line.

[0030] The aforementioned advantages of reduced pollutant emissions are achieved through the use of a three-way catalytic converter or an oxidation catalyst. In this case, an uncoated particulate filter can also be placed separately before or, preferably, after the catalytic converter in the exhaust gas recirculation line. This prevents an additional pressure increase in the exhaust system and thus avoids higher fuel consumption of the gasoline engine.

[0031] If the exhaust gas to be recirculated is taken upstream of the catalytic converter in the exhaust system, an additional three-way catalytic converter or an oxidation catalyst can be integrated into the exhaust gas recirculation line. However, these catalysts represent an additional component that can be avoided by using a catalytically coated particulate filter.

[0032] In any case, the oxidation of pollutant components leads to heat generation and thus to the heating of the downstream particulate filter. This extends the use of the particulate filter's independent regeneration during deceleration to other engine operating conditions.

[0033] Furthermore, it can be advantageous to provide at least one additional exhaust gas recirculation (EGR) line that branches off from the first EGR line and connects to the intake pipe, with at least one cooler optionally provided in at least one of these additional EGR lines. This additional EGR line allows for the implementation of various EGR architectures, particularly maximum pressure EGR.

[0034] For this purpose, it can be advantageous if the second exhaust gas recirculation line branches off downstream of the particulate filter of the first exhaust gas recirculation line. The second exhaust gas recirculation line is thus supplied with cleaned exhaust gas.

[0035] It is advantageous that at least one particulate filter has a catalytically active coating, such as a three-way coating for converting NOx, CO, and HC to N2, CO2, and H2O, or an oxidation coating similar to an oxidation catalyst for oxidizing CO and HC to CO2 and H2O. This, in turn, leads to reduced pollutant emissions in the intake system, which can further improve combustion. The particulate filter coating is effective when the engine is running. The same applies to the filter's filtration efficiency. Regeneration of the particulate filter can occur during deceleration. A catalytic effect is not strictly necessary during deceleration due to the excess air or lack of fuel supply.Through the combination of particulate filtration and catalytic conversion of further incomplete combustion products, the exhaust gas fed back into the engine exhibits a high degree of purity with regard to both combustion products and particles. This has a positive effect on the formation of deposits in the intake system as well as on combustion, and thus on the pollutant emissions of the gasoline engine.

[0036] It can also be advantageous if the main exhaust catalyst is located downstream of the first exhaust gas recirculation (EGR) branch, upstream of the second EGR branch, or downstream of the second EGR branch. Depending on its positioning, catalytic cleaning of the exhaust gas stream is ensured. By combining it with coated particulate filters, comprehensive catalytic cleaning of the entire exhaust gas stream can be achieved.

[0037] Furthermore, it can also be advantageous if at least one additional particulate filter is free of a catalytically active coating for the conversion of CO, HC and / or NOx and is located downstream of the main exhaust catalyst, and optionally an additional exhaust catalyst is located upstream of the respective particulate filter within the first exhaust gas recirculation line. This particulate filter then also does not function as an oxidation catalyst.

[0038] In connection with the design and arrangement according to the invention, it can be advantageous if at least one cooler is provided downstream of the at least one particulate filter and the at least one further particulate filter within the exhaust gas recirculation line and / or within the second exhaust gas recirculation line. The cooler is spatially or at least thermally separated from the particulate filter so that the particulate filter maintains high temperatures under as many engine operating conditions as possible, enabling it to regenerate through oxidation of the filtered components when there is excess oxygen in the exhaust gas (lambda > 1). This achieves the largest possible operating range for the particulate filter to regenerate. The cooler is designed either as an exhaust gas-to-air cooler, an exhaust gas-to-engine coolant cooler, or an exhaust gas-to-low-temperature coolant cooler.In special embodiments, several coolers, which can also be designed to be switchable, can be arranged in series or in parallel for exhaust gas recirculation.

[0039] For example, in the case of a high-pressure EGR system, it can be advantageous if the cooler has an exhaust gas target temperature (Ta) on the outlet side that is above the dew point of the substances contained in the exhaust gas, e.g., 250°C ≥ Ta ≥ 100°C or 200°C ≥ Ta ≥ 105°C. The exhaust gas target temperature (Ta) is chosen to be high enough to prevent condensation of the substances contained in the exhaust gas, including water. Cooling to below 100°C only occurs in the second cooling stage after the exhaust gas and fresh air have been mixed in the intake or charge air duct shortly before entering the engine. This allows any condensing water to enter the combustion chamber directly and, through evaporation, have a positive effect on combustion. Because the exhaust gas is cleaned by the particulate filter, there is no risk of soot buildup in an engine-mounted charge air cooler, as explained below, despite the further cooling.

[0040] It can also be advantageous to have at least one compressor in the intake manifold, wherein a) the first exhaust gas recirculation line branches off upstream of the turbine and terminates upstream or downstream of the compressor, and / or b) the second exhaust gas recirculation line branches off downstream of the turbine and terminates upstream of the compressor. Branching off upstream of the turbine ensures higher exhaust gas temperatures, which have an overall positive effect on particulate filter regeneration and pollutant reduction. Terminating downstream of the compressor has the advantage of a shorter control path. This combination of branching off upstream of the turbine and terminating downstream of the compressor is referred to as high-pressure EGR (HP-EGR). However, a sufficiently high pressure differential between the exhaust system and the intake system to supply the desired amount of recirculated exhaust gas may not be available in all desired operating conditions.If additional cooling of the recirculated exhaust gas is required, the cleaned exhaust gas can also be fed into the intake system after the compressor and before the charge air cooler. This cools the exhaust gas not only in the EGR cooler but also in the charge air cooler. It is also conceivable that the charge air cooler is designed to be so efficient that no EGR cooler is required in the EGR line for the recirculated exhaust gas.

[0041] The branch upstream of the turbine, in combination with the outlet upstream of the compressor, is referred to as maximum pressure EGR (MP-EGR) and ensures a large pressure differential within the EGR line, even for higher required exhaust gas recirculation volumes. However, this results in a longer control path than with high pressure EGR, and the compressor and turbine may need to be adapted to the changed mass flow rates.

[0042] The branching off downstream of the turbine, combined with the outlet upstream of the compressor, is referred to as low-pressure EGR (LP-EGR). This arrangement has the advantage that it can recirculate exhaust gas into the intake system even in operating conditions where the pressure differential is insufficient for high-pressure EGR. Furthermore, LP-EGR is characterized by a lower exhaust gas temperature, since the exhaust gas is extracted after the turbine, thus reducing the required cooling capacity of the EGR cooler. Additionally, the compressor in the intake manifold must be designed for the higher mass flow rate.

[0043] In the case that the exhaust gas is taken from the exhaust pipe after the catalyst, the particulate filter located in the exhaust gas recirculation line does not require a coating to convert further pollutants.

[0044] It can be advantageous if at least one additional exhaust gas recirculation line terminates in the intake pipe before or after the compressor. This additional exhaust gas recirculation line allows for the implementation of both maximum-pressure and high-pressure EGR.

[0045] Furthermore, it can be advantageous to have two compressors in the inlet line, with at least one additional exhaust gas recirculation line connecting between the two compressors. Using two compressors allows for intermediate solutions of maximum-pressure EGR, high-pressure EGR, and / or low-pressure EGR.

[0046] In this context, it can be advantageous to have two compressors arranged in the inlet line and at least two further exhaust gas recirculation lines, which are connected in parallel via a common distribution line branching off from the first exhaust gas recirculation line, wherein at least one further exhaust gas recirculation line terminates upstream of at least one of the compressors and / or at least one further exhaust gas recirculation line terminates downstream of at least one of the compressors. Each compressor is preferably assigned a turbine. At least one exhaust gas recirculation line can also be part of the distribution line if it is designed as a continuation of the distribution line.

[0047] Advantageously, an intercooler and / or an intercooler throttle valve can be provided in the intake manifold, with the outlet of the first exhaust gas recirculation (EGR) line being located downstream of the intercooler and / or the intercooler throttle valve. Typically, only fresh air is carried in the intake manifold up to the outlet of the EGR line. In this case, the intercooler could also be referred to as a fresh air cooler.

[0048] Alternatively, it can be advantageous to have an intercooler and / or an intercooler throttle valve in the intake manifold, with the outlet of the first exhaust gas recirculation (EGR) line positioned upstream of the intercooler. Cleaning the recirculated exhaust gas by the particulate filter ensures the effective use of the intercooler for the fresh air / exhaust gas mixture. Sooting of the intercooler is prevented by the particulate filter. By using an EGR line in a gasoline engine, soot particles and exhaust gas temperature can be significantly reduced under high load. Therefore, with the use of a particulate filter in the EGR line and / or intensive cooling of the recirculated exhaust gas (EGR cooling), and the charge air cooling can be enhanced to such an extent that the exhaust gas temperature can drop to the level of diesel engines, or the intake air temperature before cylinder entry can drop to the level of gasoline engines without EGR.This significantly reduces the tendency of the gasoline engine to knock and results in significant improvements in fuel consumption.

[0049] For this purpose, it can be advantageous if the charge air cooler has a charge air setpoint temperature Tu at the outlet, with 50°C ≥ Tu. Through intensive cooling of the charge air, the exhaust gas temperature of the gasoline engine can be reduced to the level of diesel engines (approximately 850°C). This has a very positive effect on the knocking tendency of the gasoline engine, and significant improvements in fuel consumption are possible.

[0050] Furthermore, it can be advantageous to install a fresh air cooler in the intake manifold in addition to the charge air cooler, positioned upstream of the exhaust gas recirculation (EGR) outlet. The fresh air cooler allows for separate cooling of the fresh air before it mixes with the exhaust gas. However, because the temperature of the compressed fresh air is not particularly high (150°C to 160°C), separate cooling of the fresh air can be omitted, in which case the fresh air / exhaust gas mixture can be cooled together in the charge air cooler as described above.

[0051] In this context, it can be advantageous if the fresh air cooler has a target fresh air temperature Tf at the outlet side of 150°C >= Tf >= 90°C. The cooling capacity achieved in the fresh air system is advantageous in any case with regard to a fresh air-exhaust gas mixture that is as cool as possible.

[0052] The reduced knocking tendency of the gasoline engine and significant improvements in fuel consumption are achieved through the two- or three-stage cooling of the intake charge air by the EGR cooler, the charge air cooler and, if necessary, the fresh air cooler, using different temperature levels.

[0053] For this purpose, it can be advantageous if the charge air cooler is provided in the intake pipe, with the outlet of at least one further exhaust gas recirculation pipe being placed upstream in a position for the charge air cooler.

[0054] It can also be advantageous to have a throttle valve in the first and / or second exhaust gas recirculation line, allowing the exhaust gas mass flow within the recirculation line to be adjusted depending on the operating point. The throttle valve is positioned downstream or upstream of at least one particulate filter or at least one additional particulate filter. During engine overrun phases, the control valve can be used to influence the regeneration of the particulate filter by adjusting the amount of recirculated fresh air. In special designs, the throttle valve can also be located directly downstream of the particulate filter. A design housed in a common casing is also possible for this purpose. Positioning the throttle valve upstream of the particulate filter leads to increased fouling of the throttle valve and is only considered in exceptional cases.

[0055] It can also be advantageous to have at least one cooler within the first exhaust gas recirculation line and / or within the second exhaust gas recirculation line, with the throttle valve located downstream or upstream of the cooler. Separate cooling of the recirculated exhaust gas allows for a reduction in the cooling capacity required in the intake manifold, or even lower temperatures in the intake manifold.

[0056] Furthermore, it can be advantageous to include an additional cooler within each subsequent exhaust gas recirculation line, or to place an additional cooler in the distribution line upstream of each subsequent exhaust gas recirculation line. This ensures and distributes the cooling capacity appropriately in each path.

[0057] Furthermore, it can be advantageous if the exhaust system has two parallel exhaust sections that can be switched via an adjustable valve, with the exhaust catalyst located in one exhaust section and at least one additional particulate filter and the subsequent branch for a further exhaust gas recirculation line in the parallel exhaust section. This allows the additional exhaust gas recirculation line to be bypassed, while ensuring catalytic cleaning of the exhaust gas in any case.

[0058] Furthermore, it can be advantageous if the second exhaust gas recirculation line and the further exhaust gas recirculation line are coupled via a controllable valve, with a cooler and / or a throttle valve located downstream of the valve. This design allows for the alternative implementation of maximum-pressure and low-pressure EGR.

[0059] Additionally, it can be advantageous to include a throttle valve in each of the subsequent exhaust gas recirculation lines. This allows the various subsequent exhaust gas recirculation lines to be activated as needed, depending on the timing and exhaust gas volume.

[0060] Furthermore, it can be advantageous to position the throttle valve downstream of the radiator. This protects it from excessive temperature stress.

[0061] It can also be advantageous to have a main particulate filter downstream of the main exhaust catalyst, which is free of a catalytically active coating for converting CO, HC and / or NOx. This ensures comprehensive removal of particles from the exhaust gas.

[0062] Another advantage is that the turbine is designed as a VTG turbine. A VTG turbine is a turbine with variable turbine blade geometry and, ideally, continuously adjustable. Only the use of EGR systems with particulate filters makes it possible to reduce the exhaust gas temperature from the gasoline engine upstream of the VTG turbine to a temperature level that corresponds to the current thermal and economic load limits of conventional VTG turbines from diesel engines.

[0063] The lower exhaust gas temperature opens up a wider range of applications for VTG turbines, making them a viable alternative to two-stage turbocharging systems for gasoline engines. The extended control range of the exhaust backpressure before the turbine inlet, enabled by the VTG function, allows EGR systems, whether high-pressure (HD) or medium-pressure (MD), to operate at higher exhaust gas recirculation rates (EGR rates), particularly at low engine speeds and high loads (LET - low end torque). This allows HD or MD versions to now cover operating ranges previously only achievable with low-pressure (ND) versions, while maintaining and potentially improving their advantage in dynamic response due to the short control loop.This advantage is further enhanced by the use of VTG turbines, as the extended and flexible control of the exhaust back pressure allows for a more precise and flexible adjustment of the EGR rate. Adjusting the EGR rate and exhaust back pressure becomes increasingly important at higher EGR rates, since gasoline engines are much more sensitive to changes in EGR rates compared to diesel engines.

[0064] EGR systems with particulate filters thus make the use of VTG turbines in gasoline engines attractive and offer a cost-effective alternative to two-stage systems. Conversely, the use of VTG turbines in HP and MP versions ensures high EGR rates across a wide operating range. More expensive, and therefore high-alloy, VTG turbines, as are known for gasoline engines without separate or two-stage exhaust gas recirculation cooling, and their associated costs can be avoided.

[0065] The problem can also be solved by an exhaust system and / or a gasoline engine with an exhaust gas recirculation system, or by a gasoline engine with a total displacement of at least Vm and with at least one exhaust gas recirculation system and / or an exhaust system as described above, wherein all particulate filters have a total volume Vf, where the following applies to the total volume Vf: 0.1 Vm ≤ Vf ≤ 1 Vm or, in particular, 0.1 Vm ≤ Vf ≤ 0.5 Vm. The total volume Vf refers to the geometric volume of the particulate filter, i.e., the volume that the housing for receiving the particulate filter has.

[0066] Additionally, it can be advantageous to use several particulate filters that together have a total volume Vf. The various particulate filters can be located in the different exhaust or recirculation lines and connected in series or parallel.

[0067] To prevent the introduction of abrasion particles into the intake tract through the EGR when using a filter, an additional filter or screen can be placed downstream of the particulate filter in the EGR.

[0068] Further advantages and details of the invention are explained in the claims and the description and illustrated in the figures. These show: Fig. 1. A schematic diagram of a combinable HD and ND EGR; Fig. 2 a schematic diagram of an MD-AGR; Fig. 3a, Fig. 3b Schematic diagrams of a combined HD and MD EGR with different cooler arrangements and inlets into the intake pipe; Fig. 4a, Fig. 4b Schematic diagrams of a combined HD, MD and ND EGR with different cooler arrangements and inlets into the intake pipe; Fig. 5a, Fig. 5b Schematic diagrams of a partial HD or MD EGR, in which the entire exhaust gas of a cylinder is recirculated; Fig. 6 a schematic diagram according to Fig. 1 with charge air cooler and fresh air cooler.

[0069] In all the schematic diagrams according to the Fig. Figure 1-6 shows an exhaust gas recirculation system 1 (EGR system) integrated into the exhaust and charge air system of a gasoline engine 2 with a displacement of 2.4 liters. The engine has an exhaust manifold 2.1, an intake manifold 2.2, an exhaust turbine 3, and a charge air compressor 4. The exhaust and charge air system includes an exhaust pipe 1.1 connected 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 section (not shown). An intake pipe 1.2 is also provided, connected to the intake manifold 2.2 of the gasoline engine 2, and the compressor 4 is integrated into this intake pipe. The intake pipe 1.2 is supplied with fresh air 7 via an air supply system (not shown). Additionally, at least one exhaust gas recirculation line 1.3, 1.3a, 1.3b (EGR line) is provided, which branches off from the exhaust gas line 1.1 and leads into the inlet line 1.2.

[0070] Either a particulate filter 1.4 is located in the EGR line 1.3, or alternatively (shown with a dashed line) a particulate filter 1.4 is arranged in the exhaust line 1.1 upstream of the EGR line 1.3, which filters the recirculated or recirculated exhaust gas 8. Alternatively (shown with a dashed line), the respective particulate filter 1.4x can also be provided with a 3-way catalyst coating or an oxidation coating to perform a catalyst function.

[0071] Furthermore, at least one EGR cooler 1.7, 1.7a, 1.7b is provided in the EGR line 1.3 downstream of the particulate filter 1.4, 1.4x. Downstream of the respective EGR cooler 1.7, 1.7a, 1.7b, or before the connection to the intake line 1.2, an EGR throttle valve 1.8, 1.8a, 1.8b is located for regulating the mass flow within the EGR line 1.3, 1.3a.

[0072] Basically, there are three variants of exhaust gas recirculation, depending on the branch of the EGR line from the exhaust line 1.1 and the opening of the EGR line in the intake line 1.2.

[0073] The combination of the branch of the EGR line 1.3 upstream of the turbine 3 and the outlet of the EGR line 1.3 downstream of the compressor 4 is referred to as high-pressure EGR (HP-EGR).

[0074] The combination of the branch of the EGR line 1.3 upstream of the turbine 3 and the outlet of the EGR line 1.3 upstream of the compressor 4 is referred to as maximum pressure EGR (MD-EGR).

[0075] The combination of the branch of the EGR line 1.3 downstream of the turbine 3 and the outlet upstream of the compressor 4 is referred to as low-pressure EGR (LP-EGR).

[0076] The three EGR variants mentioned above can be used individually or combined with each other.

[0077] To further influence the amount of exhaust gas recirculated, a throttle valve can be installed in the inlet line 1.2 upstream of the point where the exhaust gas recirculation line 1.3 enters the inlet line 1.2.

[0078] In the diagram according to Fig. Figure 1 shows various EGR variants as supplementary or alternatives. Within the inlet line 1.2, downstream of the compressor 4, an intercooler 5 and an intercooler throttle valve 6 are provided.

[0079] There is a high-pressure EGR system, formed by the EGR line 1.3, which branches off upstream of the turbine 3 and opens into the inlet line 1.2 downstream of the compressor 4. The outlet is located downstream of the charge air throttle valve 6. Alternatively, the EGR line 1.3* can open upstream of the charge air throttle valve 6 and upstream of the charge air cooler 5. Fresh air 7 is typically supplied to the inlet line 1.2 up to the outlet of the EGR line 1.3. The charge air then consists of the fresh air 7 and the recirculated exhaust gas 8. The particulate filter 1.4 can be located after Fig. 1 alternatively (shown with a dashed line) it can also be placed in the exhaust line 1.1 upstream of the EGR line 1.3.

[0080] Downstream of turbine 3, a catalyst 1.6a is provided in the exhaust line 1.1, which is configured as a three-way catalyst or as an oxidation catalyst. Notwithstanding the embodiments described below, the catalyst 1.6a, 1.6' used can, in principle, be either a three-way catalyst or an oxidation catalyst. An oxidation catalyst 1.6 is particularly suitable for lean-burn gasoline engines 2.

[0081] Downstream of the catalyst 1.6a, an additional or alternative EGR line 1.3a branches off, leading upstream of the compressor 4 and forming a low-pressure EGR system. Within this system are the particulate filter 1.4a, the EGR cooler 1.7a, and an EGR throttle valve 1.8a. The throttle valve 1.8a* can also be located upstream of the particulate filter 1.4.

[0082] Alternatively, the EGR line 1.3a* can branch off upstream of the catalyst 1.6a. In this case, the particulate filter 1.4ax has a 3-way catalyst coating or an oxidation coating to compensate for bypassing the catalyst 1.6a. It should also be noted that, regardless of the embodiments described below, the coating used on the particulate filter 1.4x, 1.4ax can fundamentally be either a 3-way catalyst coating or an oxidation coating. An oxidation coating is particularly suitable for lean-burn gasoline engines 2.

[0083] Additionally (shown with a dashed line) a main particulate filter 1.4' can be placed in the exhaust line 1.1 downstream of the EGR line 1.3a.

[0084] As an alternative to this low-pressure EGR, the catalyst 1.6a and, downstream, the particulate filter 1.4a are provided in the exhaust line 1.1, with the EGR line 1.3a branching off only downstream of the particulate filter 1.4a. The EGR cooler 1.7a and the EGR throttle valve 1.8a are located in the EGR line 1.3a.

[0085] As a further alternative A2 for the low-pressure EGR, the exhaust line 1.1 is equipped with two parallel exhaust line sections 1.1a and 1.1b, which can be switched via a controllable valve 1.9. A main exhaust catalyst 1.6' is located in exhaust line section 1.1a. The coated particulate filter 1.4ax and the branch for the EGR line 1.3a are located in the parallel exhaust line section 1.1b. Thus, a switchable bypass for the EGR line 1.3a is available, whereby in both cases three-way or at least oxidation catalysis is achieved in the exhaust lines 1.1a and 1.1b.

[0086] The adjustable valve 1.9 can also be designed so that different sized partial quantities of exhaust gas flow simultaneously through the parallel exhaust gas pipe sections 1.1a, 1.1b.

[0087] Alternatively, an uncoated particulate filter 1.4a can also be used in exhaust pipe section 1.1b. In this case, however, the exhaust catalyst 1.6* (shown with a dashed line) would be installed in exhaust pipe 1.1 before the division into the two exhaust pipe sections 1.1a and 1.1b, in order to ensure catalytic cleaning of the exhaust gas 8 in every position of the valve 1.9.

[0088] After Fig. 2 is a medium-pressure exhaust gas recirculation (MPGR) system. The particulate filter 1.4x located in the EGR line 1.3 has a catalyst coating. In addition, a main exhaust catalyst 1.6', preferably a three-way catalyst, is provided in the exhaust line 1.1 downstream of the turbine 3. The throttle valve 1.8 is located downstream of the cooler 1.7. The throttle valve 1.8* can alternatively also be located upstream of the particulate filter 1.4x. Additionally (shown with dashed lines), an uncoated main particulate filter 1.4' can be located in the exhaust line 1.1 downstream of the main exhaust catalyst 1.6'.

[0089] After Fig. 3a begins with the exhaust gas recirculation from the EGR line 1.3, which branches off from the exhaust pipe 1.1, and continues via further parallel EGR lines 1.3b - 1.3d. The particulate filter 1.4x with the catalyst coating and the cooler 1.7 are located in the EGR line 1.3. The EGR lines 1.3b - 1.3d each branch off from a distribution line 13, which in turn branches off from the EGR line 1.3 downstream of the cooler 1.7.

[0090] All EGR lines 1.3 - 1.3d terminate at the inlet line 1.2. Each of these EGR lines 1.3 - 1.3d has a throttle valve 1.8 - 1.8d downstream of the distribution line 13. All throttle valves 1.8 - 1.8d are connected via a control line 9.1 to a control unit 9 for controlling and regulating the position of the respective throttle valve 1.8 - 1.8d and can be individually controlled. Downstream of each throttle valve 1.8 - 1.8d, an additional cooler 1.7*, 1.7b - 1.7d is provided in the respective EGR line 1.3 - 1.3d. The inlet line 1.2 has two compressors 4a, 4b, each coupled to a turbine 3a, 3b of the exhaust line 1.1. EGR lines 1.3 and 1.3b both terminate downstream of compressor 4a and form a high-pressure EGR system. EGR line 1.3b terminates upstream of charge air cooler 5, while EGR line 1.3 terminates downstream of charge air cooler 5.

[0091] EGR line 1.3d connects upstream of compressor 4b and forms a medium-pressure EGR. However, EGR line 1.3c connects between both compressors 4a and 4b and therefore forms a reduced medium-pressure EGR.

[0092] According to Fig. 3a can (not shown) also be an EGR system without the upstream EGR cooler 1.7 in the EGR line 1.3.

[0093] Downstream of turbines 3a, 3b, a three-way catalytic converter (main exhaust catalyst) 1.6' is located, from which the exhaust gas 8, or the main exhaust gas flow, is routed into the further exhaust system. Additionally (shown with dashed lines), an uncoated main particulate filter 1.4' can be located in the exhaust line 1.1 downstream of the main exhaust catalyst 1.6'.

[0094] The EGR system according to Fig. 3b is similarly constructed. Here, a cooler 1.7 is provided in the EGR line 1.3, upstream of the branch of the distribution line 13, and three coolers 1.7b - 1.7d are placed in the distribution line 13, each upstream of the branch of the respective EGR line 1.3b - 1.3d. Thus, one less cooler 1.7* is needed than would be required according to [reference missing]. Fig. 3a is the case.

[0095] Both EGR systems after Fig. 3a and Fig. 3b ensures an extremely flexible EGR control, so that extensive particulate filtration and regeneration of the particulate filter 1.4x on the one hand, and the demand-based supply of cooled exhaust gas 8 into the inlet line 1.2 for a comprehensive operating range of the engine on the other hand, are always guaranteed.

[0096] The EGR systems according to Fig. 4a, Fig. 4b includes a high-pressure EGR, a medium-pressure EGR, and a low-pressure EGR. The charge air cooler 5 and the charge air throttle valve 6 are located in the intake line 1.2, while the exhaust line 1.1 downstream of the turbine 3 is equipped with a 3-way catalytic converter 1.6a and a downstream particulate filter 1.4a.

[0097] Example of implementation Fig. In section 4a, a coated particulate filter 1.4x is initially provided in the EGR line 1.3. A further EGR line 1.3b then branches off. While EGR line 1.3, as high-pressure EGR, connects to the exhaust line 1.1 downstream of the charge air throttle valve 6, EGR line 1.3b, as medium-pressure EGR, connects upstream of the compressor 4. In EGR line 1.3, downstream of EGR line 1.3b, a cooler 1.7 and a downstream throttle valve 1.8 are provided. EGR line 1.3b also includes a cooler 1.7b and a downstream throttle valve 1.8b.

[0098] In addition, a second EGR line 1.3a is provided, branching off downstream of the particulate filter 1.4a, and thus downstream of turbine 3, at the exhaust pipe 1.1. It also features a cooler 1.7a and a downstream throttle valve 1.8a before connecting to the inlet pipe 1.2 upstream of compressor 4, thus forming a low-pressure EGR system. The particulate filter 1.4a is also located in the EGR line 1.3a (shown with a dashed line).

[0099] Both HD-EGR and MD-EGR and ND-EGR are possible in any combination.

[0100] Unlike Fig. 4a are in the exemplary embodiment according to Fig. 4b The EGR line 1.3b and the EGR line 1.3a are coupled via a controllable valve 1.9. This has the advantage that one cooler 1.7a / b and one throttle valve 1.8a / b are no longer required. However, only medium-pressure EGR or low-pressure EGR can be implemented in addition to or as an alternative to high-pressure EGR. Furthermore, the particulate filter 1.4 in the EGR line 1.3 is uncoated, so an additional exhaust catalyst 1.6 is provided upstream.

[0101] Both Fig. 5a and Fig. 5b is the EGR line 1.3 assigned to a single cylinder outlet 2.3 of the gasoline engine 2 and carries the exhaust gas quantity of this cylinder outlet 2.3. The charge air cooler 5 and the charge air throttle valve 6 are located in the intake line 1.2, while the exhaust line 1.1 downstream of the turbine 3 is equipped with a 3-way catalytic converter 1.6' and a downstream main particulate filter 1.4'.

[0102] After Fig. 5a is a high-pressure EGR system. The EGR line 1.3 has a coated particulate filter 1.4x and a downstream cooler 1.7, as well as a throttle valve 1.8 located downstream of the cooler 1.7. In an example not shown, an uncoated particulate filter 1.4 may also be used.

[0103] In Fig. 5b is supplemented with an MD-EGR. For this purpose, a further EGR line 1.3b branches off between the coated particulate filter 1.4x and the cooler 1.7, leading upstream of the compressor 4. This EGR line 1.3b also contains another cooler 1.7b and a downstream throttle valve 1.8b. In an example not shown, an uncoated particulate filter 1.4 could also be provided in the EGR line 1.3.

[0104] The exemplary embodiment Fig. Except for the position of the charge air throttle valve 6, version 6 essentially corresponds to the variant according to Fig.1. However, two coolers are provided in the inlet line 1.2. An intercooler 5.1 is positioned downstream of the outlet of the first exhaust gas recirculation line 1.3, and a second, so-called fresh air cooler 5.2 is positioned upstream of the outlet of the first exhaust gas recirculation line 1.3. In the downstream intercooler 5.1, the compressed and, if necessary, pre-cooled fresh air 7, together with the recirculated and pre-cooled exhaust gas 8, are cooled to the desired setpoint temperature Ta. The turbine 3 is a variable turbine geometry (VTG) turbine of a design and material composition typical for diesel engines. Reference symbol list 1 Exhaust system / Exhaust gas recirculation system 1.1 Exhaust pipe, main exhaust pipe 1.1a Exhaust pipe section 1.1b Exhaust pipe section 1.2 Inlet pipe, charge air pipe, fresh air pipe 1.3 First exhaust gas recirculation line, EGR line 1.3* First exhaust gas recirculation line, EGR line 1.3a Second exhaust gas recirculation line, EGR line 1.3a* second exhaust gas recirculation line, EGR line 1.3b further exhaust gas recirculation line, EGR line 1.3c further exhaust gas recirculation line, EGR line 1.3d further exhaust gas recirculation line, EGR line 1.4 Particle filter 1.4a Particle filter 1.4' Main particulate filter 1.4x coated particle filters 1.4ax particle filter, coated 1.6 Additional exhaust gas, 3-way or oxidation catalyst 1.6a Main exhaust catalyst or 3-way or oxidation catalyst 1.6' Main exhaust catalyst or 3-way or oxidation catalyst 1.6* Exhaust gas, 3-way or oxidation catalyst, alternatively 1.7 first cooler 1.7* additional cooler 1.7a second cooler 1.7b additional cooler 1.7c additional cooler 1.7d additional cooler 1.8 Throttle valve 1.8* Throttle valve alternatively before 1.7 1.8a Throttle valve 1.8a* Throttle valve 1.8a / b Throttle valve 1.8b Throttle valve 1.8c Throttle valve 1.8d Throttle valve 1.9 Valve, exhaust flap 2 Otto engines 2.1 Exhaust manifold 2.2 Intake manifold 2.3 Cylinder exhaust 2.4 engine displacement 3 Turbine, VTG Turbine 3a Turbine 3b Turbine 4 compressors 4a Compressor 4b Compressor 5 Intercoolers, fresh air coolers 5.1 Intercooler 5.2 Fresh air cooler 6 Charge air throttle valve 7 Fresh air 8 Exhaust gas 9 Control unit 9.1 Control line 13 Distribution line A1 Alternative A2 Alternative Vf Total volume Vm Volume

Claims

[1] Exhaust gas recirculation system (1) for a gasoline engine (2) comprising the following: an exhaust pipe (1.1) that can be connected to an exhaust manifold (2.1) of the gasoline engine (2), an intake manifold (2.2) of the Otto engine (2) that can be connected to an intake manifold (2.2), a 3-way main exhaust catalyst (1.6a, 1.6') in the exhaust pipe (1.1), at least one first exhaust gas recirculation line (1.3) branching off from the exhaust pipe (1.1) and opening into the intake pipe (1.2), at least one second exhaust gas recirculation line (1.3a) branching off from the exhaust pipe (1.1) and opening into the intake pipe (1.2), at least one particulate filter (1.4x) which: - is located in the first exhaust gas recirculation line (1.3), and at least one further particulate filter (1.4ax) which: - is located in the second exhaust gas recirculation line (1.3a), and / or - is located in the exhaust pipe (1.1) upstream of the second exhaust gas recirculation pipe (1.3a), wherein the at least one particle filter (1.4x) and the at least one further particle filter (1.4ax) have a catalytically active coating for the conversion of CO, HC and NOx. [2] Exhaust gas recirculation system (1) according to claim 1, characterized by , that the second exhaust gas recirculation line (1.3a) branches off upstream or downstream of the exhaust gas catalyst (1.6a, 1.6'). [3] Exhaust gas recirculation system (1) according to claim 1 or 2, characterized by , that at least one further exhaust gas recirculation line (1.3b, 1.3c, 1.3d) is provided, which branches off from the first exhaust gas recirculation line (1.3) and opens into the inlet line (1.2), wherein at least one cooler (1.7b, 1.7c, 1.7d) is provided in at least one of the further exhaust gas recirculation lines (1.3b, 1.3c, 1.3d). [4] Exhaust gas recirculation system (1) according to claim 3, characterized by, that the further exhaust gas recirculation line (1.3b, 1.3c, 1.3d) branches off downstream of the at least one particulate filter (1.4x) of the first exhaust gas recirculation line (1.3). [5] Exhaust gas recirculation system (1) according to any one of claims 1 to 4, characterized by , that the 3-way main exhaust catalyst (1.6a, 1.6') is provided downstream of the branch of the first exhaust gas recirculation line (1.3) or upstream of the branch of the second exhaust gas recirculation line (1.3a) or downstream of the branch of the second exhaust gas recirculation line (1.3a). [6] Exhaust gas recirculation system (1) according to claim 5, characterized by, that at least one additional particulate filter (1.4, 1.4a) is provided which is free of a catalytically active coating for the conversion of CO, HC and / or NOx and is placed downstream of the 3-way main exhaust catalyst (1.6a, 1.6') and optionally an additional exhaust catalyst (1.6) is placed upstream of the respective particulate filter (1.4, 1.4a) within the first exhaust gas recirculation line (1.3). [7] Exhaust gas recirculation system (1) according to any one of claims 1 to 4, characterized by , that downstream of the at least one particulate filter and the at least one further particulate filter (1.4x, 1.4ax) at least one cooler (1.7, 1.7a, 1.7*) is provided within the exhaust gas recirculation line (1.3) and / or within the second exhaust gas recirculation line (1.3a). [8] Exhaust gas recirculation system (1) according to claim 7, characterized by, that the cooler (1.7, 1.7a, 1.7*) has an exhaust gas target temperature Ta on the outlet side that is above the dew point of the substances contained in the exhaust gas. [9] Exhaust gas recirculation system (1) according to one of the preceding claims, wherein a turbine (3, 3a, 3b) is provided in the exhaust gas line (1.1). [10] Exhaust gas recirculation system (1) according to claim 9, characterized by , that at least one compressor (4, 4a, 4b) is arranged in the inlet line (1.2), wherein a) the first exhaust gas recirculation line (1.3) branches off upstream of the turbine (3) and leads upstream or downstream of the compressor (4, 4a, 4b) and / or b) the second exhaust gas recirculation line (1.3a) branches off downstream of the turbine (3) and leads upstream of the compressor (4, 4a, 4b). [11] Exhaust gas recirculation system (1) according to claim 10, characterized by, that at least one further exhaust gas recirculation line (1.3b, 1.3c, 1.3d) opens into the inlet line (1.2) before the compressor (4, 4a, 4b) or after the compressor (4, 4a, 4b). [12] Exhaust gas recirculation system (1) according to any one of claims 3 to 11, characterized by , that in the inlet line (1.2) two compressors (4a, 4b) are arranged, wherein at least one further exhaust gas recirculation line (1.3b) opens between the two compressors (4a, 4b). [13] Exhaust gas recirculation system (1) according to any one of claims 3 to 11, characterized by, that two compressors (4a, 4b) are arranged in the inlet line (1.2) and at least two further exhaust gas recirculation lines (1.3b, 1.3c, 1.3d) are provided, which are connected in parallel via a common distribution line (13) branching off from the first exhaust gas recirculation line (1.3), wherein at least one further exhaust gas recirculation line (1.3c, 1.3d) opens upstream of at least one of the compressors (4a, 4b) and / or at least one further exhaust gas recirculation line (1.3b, 1.3c) opens downstream of at least one of the compressors (4a, 4b). [14] Exhaust gas recirculation system (1) according to any one of claims 1 to 13, characterized by , that an intercooler (5) and / or an intercooler throttle valve (6) are provided in the inlet line (1.2), wherein the outlet of the first exhaust gas recirculation line (1.3) is located downstream of a position for the intercooler (5) and / or downstream of a position for the intercooler throttle valve (6). [15] Exhaust gas recirculation system (1) according to any one of claims 1 to 13, characterized by , that an intercooler (5.1) and / or an intercooler throttle valve (6) are provided in the inlet line (1.2), wherein the outlet of the first exhaust gas recirculation line (1.3) is placed upstream of a position for the intercooler (5.1). [16] Exhaust gas recirculation system (1) according to claim 15, characterized by , that in addition to the charge air cooler (5.1) a fresh air cooler (5.2) is placed in the intake line (1.2), the fresh air cooler (5.2) being positioned upstream of the outlet of the exhaust gas recirculation line (1.3). [17] Exhaust gas recirculation system (1) according to claim 16, characterized by , that the fresh air cooler (5.2) has a fresh air setpoint temperature Tf on the outlet side of 150° >= Tf >= 90°. [18] Exhaust gas recirculation system (1) according to claim 3, characterized by, that an intercooler (5) is provided in the inlet line (1.2), wherein the outlet of at least one further exhaust gas recirculation line (1.3b, 1.3c, 1.3d) is placed upstream of a position for the intercooler (5). [19] Exhaust gas recirculation system (1) according to any one of the preceding claims, characterized by , that a throttle valve (1.8, 1.8*, 1.8a, 1.8a*) is provided in the first exhaust gas recirculation line (1.3) and / or in the second exhaust gas recirculation line (1.3a), via which an exhaust gas mass flow within the exhaust gas recirculation line (1.3, 1.3a) can be adjusted depending on the operating point, wherein the throttle valve (1.8, 1.8*, 1.8a, 1.8a*) is located downstream or upstream of the at least one particulate filter or the at least one further particulate filter (1.4x, 1.4ax). [20] Exhaust gas recirculation system (1) according to claim 19, characterized by, that at least one cooler (1.7, 1.7*, 1.7a) is provided within the first exhaust gas recirculation line (1.3) and / or within the second exhaust gas recirculation line (1.3a), wherein the throttle valve (1.8, 1.8*, 1.8a, 1.8a*) is provided downstream or upstream of the cooler (1.7, 1.7*, 1.7a). [21] Exhaust gas recirculation system (1) according to any one of claims 9 to 20, characterized by , that each additional cooler (1.7b, 1.7c, 1.7d) is provided within the respective additional exhaust gas recirculation line (1.3b, 1.3c, 1.3d) or that each additional cooler (1.7b, 1.7c, 1.7d) is placed in the distribution line (13) upstream of the respective additional exhaust gas recirculation line (1.3b, 1.3c, 1.3d). [22] Exhaust gas recirculation system (1) according to any one of the preceding claims, characterized by, that the exhaust pipe (1.1) has two parallel exhaust pipe sections (1.1a, 1.1b) which can be switched via a controllable valve (1.9), wherein the 3-way main exhaust catalyst (1.6') is placed in the exhaust pipe section (1.1a) and the at least one further particulate filter (1.4ax) and the branch for a further exhaust gas recirculation line (1.3a) are provided in the parallel exhaust pipe section (1.1b). [23] Exhaust gas recirculation system (1) according to any one of claims 3 to 22, characterized by , that the second exhaust gas recirculation line (1.3a) and the further exhaust gas recirculation line (1.3b) are coupled via a controllable valve (1.9), wherein a cooler (1.7a / b) is provided downstream of the valve (1.9) and / or a throttle valve (1.8a / b) is provided downstream of the cooler (1.7a / b). [24] Exhaust gas recirculation system (1) according to any one of claims 3 to 23, characterized by, that a throttle valve (1.8b, 1.8c, 1.8d) is provided in the respective further exhaust gas recirculation line (1.3b, 1.3c, 1.3d). [25] Exhaust gas recirculation system (1) according to claim 24, characterized by , that the throttle valve (1.8b, 1.8c, 1.8d) is located downstream of the respective cooler (1.7b, 1.7c, 1.7d). [26] Exhaust gas recirculation system (1) according to any one of claims 1 to 25, characterized by , that downstream of the 3-way main exhaust catalyst (1.6') a main particulate filter (1.4') is provided which is free of a catalytically active coating for the conversion of CO, HC and / or NOx. [27] Exhaust gas recirculation system (1) according to any one of claims 9 to 26, characterized by , that the turbine (3) is designed as a VTG turbine. [28] Exhaust system and / or gasoline engine (2) with an exhaust gas recirculation system (1) according to any of the preceding claims. [29] Otto engine (2) with at least a displacement (2.4) having a volume Vm and with at least one exhaust gas recirculation system (1) and / or an exhaust system according to one of the preceding claims, characterized by , that all particle filters have a total volume Vf, where the following applies to the total volume Vf: 0.1 Vm <= Vf <= 1 Vm or 0.1 Vm <= Vf <= 0.5 Vm. [30] Otto engine (2) according to claim 29, characterized by that all particle filters together have a total volume Vf.

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