DE102015108223B4 - EGR system with particle filter and wastegate - Google Patents

Abstract

Exhaust gas routing system (1) for a gasoline engine (2) for use in a method according to one of claims 11 to 13 with an exhaust pipe (2.3) connectable to an exhaust manifold (2.1) of the gasoline engine (2), with an intake manifold (2.2) of the Petrol engine (2) connectable inlet pipe (2.4) and with a in the exhaust pipe (2.3) arranged turbine (3), characterized in that at least one exhaust gas recirculation line (1.1a, 1.1c) is provided with an EGR valve 1.3, in the Inlet line (2.4) opens, and that the exhaust line (2.3) has at least one bypass line (1.1b) with a bypass throttle 1.4, which opens downstream of the turbine (3) in the exhaust pipe (2.3), a) the exhaust gas recirculation line ( 1.1a) branches off upstream of the turbine (3) and the bypass line (1.1b) branches off at the exhaust gas recirculation line (1.1a) orb) the bypass line (1.1b) branches off upstream of the turbine (3) and the exhaust gas recirculation line (1.1a ) at the bypass s line (1.1b) branches off, wobeicic) in the exhaust gas recirculation line (1.1a) or in the bypass line (1.1b) upstream of the exhaust gas recirculation line (1.1a) or in the exhaust pipe (2.3) upstream of the exhaust gas recirculation line (1.1a) at least a particulate filter (1.2x) is arranged, wherein the at least one particulate filter (1.2x) has a catalytically active coating for the conversion of CO, HC and NOx, wherein downstream of the turbine (3) designed as a 3-way catalyst exhaust gas catalyst (5 ) is provided.

Description

The invention relates to a method for operating a gasoline engine with an exhaust gas routing system or an exhaust system as described below.

The invention relates to an exhaust gas guidance system for a gasoline engine for the application of the method with an exhaust pipe connectable to an exhaust manifold of the gasoline engine, with an inlet pipe connectable to an intake manifold of the gasoline engine and with a turbine arranged in the exhaust gas pipe.

From the US 5,671,600 A is known an exhaust gas recirculation system for diesel engines. At the exhaust outlet or on the exhaust pipe, a particulate filter is provided, followed by an exhaust gas recirculation line. The exhaust gas recirculation line opens upstream of a charge air compressor in the inlet line. Within the exhaust gas recirculation line, a valve for changing the exhaust gas mass flow is provided. The particle filter serves to protect the charge air compressor or intercooler from contamination.

From the DE 10 2012 021 882 A1 is a particle filter in the main exhaust gas stream of a gasoline engine known. Unlike the diesel engine, the particle filter regenerates as far as possible without additional active measures, ie the particle mass retained so far (soot particles with attached or stored hydrocarbons) essentially burns to CO2 or to H 2 O under normal boundary conditions. For this purpose, sufficiently high exhaust gas temperatures of more than 500 ° C and oxygen for combustion are required. This exhaust gas temperature is reached soon after engine start in various operating ranges of the gasoline engine. Since the vast majority of gasoline engines is operated stoichiometrically, the oxygen content in the exhaust gas may be too low for a complete burnup of the particle mass contained in the filter. In this case, in conventional operation, fuel cut-off phases of the gasoline engine, in which the injection of the engine is shut down for consumption reasons due to the loss of the load request by the driver, do not help. Since the engine, with the gear engaged as an engine brake, reduces vehicle speed, the towed engine flushes clean air through the exhaust system. This unburned air encounters the previously heated by the engine exhaust particles in the particulate filter.

At a sufficient temperature, these particles ignite and burn to gases that may escape through the particulate filter. This will clean the particulate filter.

From the DE 10 2013 003 701 A1 , of the DE 10 2013 008 426 and the WO 2008 127 755 A2 Additional measures such as a secondary air system to actively achieve the regeneration of the particulate filter by excess air are known.

The DE 10 2009 014 277 A1 describes a device for operating a diesel internal combustion engine with an exhaust pipe and an exhaust gas recirculation line, which connects to an inlet line. The exhaust gas recirculation line can optionally be connected to the exhaust system via a 3-way valve in a regeneration operation of the diesel particulate filter located in the exhaust gas recirculation line. During regular operation, the exhaust gas recirculation line is in flow connection via the three-way valve to the inlet line for the purpose of recirculating exhaust gas.

The DE 10 2010 046 747 A1 describes a method for operating a gasoline engine with 3-way catalytic converter and downstream particle filter. For the purpose of regeneration of the particulate filter located in the exhaust line, a bypass is provided, which is guided past the 3-way catalyst, wherein within this bypass, an air pump for supplying secondary air for the purpose of regeneration of the particulate filter is provided. At the same time, a low-pressure exhaust gas recirculation line is supplied with secondary air.

The EP 2 194 351 B1 describes an exhaust gas cooler for a diesel engine.

The EP 1 405 995 A1 shows an exhaust system for a diesel engine with an exhaust gas recirculation line and a bypass line, which branch off downstream of a cleaning unit.

The FR 2 894 624 A1 shows an exhaust system for a reciprocating internal combustion engine with an exhaust gas recirculation line and a bypass line, which have a common cleaning unit.

The object of the invention is to design and arrange an exhaust gas guidance system for a gasoline engine such that improved regeneration of the particulate filter is achieved.

1. a) im Betrieb bzw. im Schubbetrieb des Ottomotors bei zumindest teilweise geschlossenem AGR-Ventil zumindest ein Teil des Abgasstroms durch den Partikelfilter und durch die zumindest teilweise geöffnete Bypass-Leitung geführt wird, wobei eine Regeneration des Partikelfilters ausgeführt bzw. ermöglicht wird;
2. b) während und nach dem Start des Ottomotors bei zumindest teilweise geschlossenem AGR-Ventil durch Öffnen der Bypass-Drosselklappe zumindest ein Teil des Abgasstroms durch den Partikelfilter und durch die Bypass-Leitung an der Turbine vorbei geführt wird, bis ein vorgegebener Abgasdruck erreicht ist;
3. c) im Volllastbetrieb des Ottomotors oder zumindest volllastnah die Bypass-Leitung als Wastegate verwendet wird zum Leiten von zumindest einem Teil des Abgasstroms an der Turbine vorbei, wobei hierdurch eine Regeneration des Partikelfilters ausgeführt bzw. ermöglicht wird. Das AGR-Ventil kann dabei zumindest teilweise oder ganz geöffnet sein.

The task is solved by the fact that

1. a) during operation or in overrun of the gasoline engine with at least partially closed EGR valve at least a portion of the exhaust gas flow through the particulate filter and through the at least partially opened bypass line is performed, with a regeneration of the particulate filter is performed or enabled;
2. (b) during and after the start of the gasoline engine with at least partially closed EGR Valve is passed by opening the bypass throttle at least part of the exhaust gas flow through the particulate filter and the bypass line to the turbine over until a predetermined exhaust pressure is reached;
3. c) in full load operation of the gasoline engine or at least full load close the bypass line is used as a wastegate for passing at least part of the exhaust gas flow past the turbine, thereby performing a regeneration of the particulate filter is made possible. The EGR valve can be at least partially or completely open.

By using the bypass line according to the invention, the engine behavior or the pollutant emission can be significantly improved in various operating points.

• a) das AGR-Ventil geöffnet wird und wahlweise ergänzend Abgas durch die Bypass-Leitung geführt wird, wobei die Bypass-Drosselklappe zumindest teilweise geöffnet ist oder
• b) das AGR-Ventil geschlossen wird und alternativ Abgas durch die Bypass-Leitung geführt wird, wobei die Bypass-Drosselklappe zumindest teilweise geöffnet ist. Der zusätzlich eingebrachte Massestrom kann über die Bypass-Leitung oder die AGR-Leitung abgeführt werden. Im zuletzt genannten Fall ist eine verbesserte Regeneration des Partikelfilters gewährleistet.

It may be advantageous for this purpose when introducing secondary air through the device

• a) the EGR valve is opened and optionally additionally exhaust gas is passed through the bypass line, wherein the bypass throttle is at least partially open or
• b) the EGR valve is closed and alternatively exhaust gas is passed through the bypass line, wherein the bypass throttle valve is at least partially open. The additionally introduced mass flow can be dissipated via the bypass line or the EGR line. In the latter case, an improved regeneration of the particulate filter is ensured.

1. a) die Abgasrückführungsleitung stromauf der Turbine abzweigt und die Bypass-Leitung an der Abgasrückführungsleitung abzweigt oder
2. b) die Bypass-Leitung stromauf der Turbine abzweigt und die Abgasrückführungsleitung an der Bypass-Leitung abzweigt, wobei
3. c) in der Abgasrückführungsleitung oder in der Bypass-Leitung stromauf der Abgasrückführungsleitung oder in der Abgasleitung stromauf der Abgasrückführungsleitung bzw. der Bypass-Leitung mindestens ein Partikelfilter angeordnet ist, wobei, wobei der mindestens eine Partikelfilter eine katalytisch wirkende Beschichtung zur Umwandlung von CO, HC und NOx aufweist, wobei stromab der Turbine ein als 3-Wege-Katalysator ausgebildeter Abgaskatalysator vorgesehen ist.

The object is also achieved by carrying out the method by means of an exhaust gas guidance system for a gasoline engine, in which at least one exhaust gas recirculation line is provided with an EGR valve, which opens into the inlet pipe, and wherein the exhaust pipe at least one bypass line with a bypass throttle has, which opens downstream of the turbine in the exhaust pipe, wherein

1. a) the exhaust gas recirculation line branches off upstream of the turbine and the bypass line branches off at the exhaust gas recirculation line or
2. b) the bypass line branches off upstream of the turbine and the exhaust gas recirculation line branches off at the bypass line, wherein
3. c) in the exhaust gas recirculation line or in the bypass line upstream of the exhaust gas recirculation line or in the exhaust pipe upstream of the exhaust gas recirculation line or the bypass line at least one particulate filter is arranged, wherein, the at least one particulate filter, a catalytic coating for the conversion of CO, HC and NOx, wherein downstream of the turbine designed as a 3-way catalyst exhaust catalyst is provided.

When the bypass line branches off at the exhaust gas recirculation line, the branch is preferably downstream of the particulate filter of the exhaust gas recirculation line. Thus, the bypass line is also supplied with the particulate filter.

The exhaust control system described here has an exhaust gas recirculation system (EGR system) in its core. An EGR system typically consists of at least one exhaust gas recirculation (EGR) line, one exhaust gas recirculation (EGR) cooler, and one exhaust gas recirculation (EGR) valve.

In the EGR system and in the intake system of gasoline engines deposits are observed, which are called "wet soot" or "fouling", which can have serious consequences such as reduced cooling capacity, blockage, poor uniform distribution and irregular combustion. Therefore, EGR systems are rarely used in gasoline engines and with restrictions.

In EGR systems for gasoline engines, cooling the recirculated exhaust gas to optimize combustion is advantageous because recirculation of uncooled exhaust gases, especially at higher loads and at full load, leads to higher intake temperatures due to the hot exhaust gases supplied. This in turn has filling losses and an increase in the tendency to knock the gasoline engine result. This is accompanied by undesirable power losses of the engine. These disadvantages can be reduced by cooling the recirculated exhaust gas. But this has the emergence of an increased amount of condensates - consisting of water and / or hydrocarbons or hydrocarbon compounds and incompletely burned combustion residues - in the recirculated exhaust gas result, resulting in an increased degree of sooting in the form of wet, adhesive deposits in the EGR and Intake air system leads. A combination of the particulate filter with the intercooler, as it is EP 2 194 351 B1 for a diesel particulate filter is therefore not considered to avoid a risk of clogging by the deposits previously described in the particulate filter.

In addition, a particulate filter achieves the minimum temperature required in the particulate filter for the self-regeneration of the particulate filter only in a clearly limited operating range. It is in this. Case additional active regeneration measures, the operational and cost of disadvantage are required. In contrast to the wet constituents entrained in the Otto exhaust gas, diesel particles are drier constituents which have a lower tendency to condense and stick together. In addition, active regeneration measures for the particulate filter in the diesel engine due to the prevailing lower exhaust gas temperatures generally required in very wide engine operating ranges.

Particle filters for gasoline engines as well as diesel particulate filters retain particles. For regeneration of the particulate filter, d. H. For the combustion of filtered particles sufficiently high exhaust gas temperatures and oxygen excess are required. After a warm-up phase, these conditions are available for the exhaust gas properties in gasoline engine EGR systems. In far. Operating areas of the gasoline engine, ie in the fired state (lambda = 1 in stoichiometrically operated gasoline engines) but lacks an excess of oxygen as a basis for complete combustion of the particles in the particulate filter. Thus, only particles are fed to the particulate filter by the exhaust gas flow, where they are burned to a part with the available residual oxygen and, on the other hand, retained there until sufficiently good combustion conditions are available for the complete burnup. A regeneration, thus a combustion of the particles can only take place in deceleration phases of the engine when the injection is switched off. During this overrun phase, ie when the engine continues to rotate and intake and exhaust valve actuation, oxygen enters the EGR system when the EGR valve is open and flows through the particulate filter integrated there. At sufficient temperature in the particle filter, the particles are then burned to CO2. It may also be CO, HC and / or NOx.

In overrun operation, the EGR valves are usually closed in the gasoline engine to at a renewed load request by the driver or when reaching the idle speed of the engine by minimizing the residual gas amount not to endanger the immediate ignition of the engine.

However, in order to allow regeneration of the particulate filter in the EGR line, for example, in the overrun operation, the opening of the EGR valve is required. Thus, exhaust gas having a high oxygen content flows through the particulate filter and regenerates it. This regeneration continues until the particles or the exhaust gas falls below the minimum temperature required for the regeneration by the cooler air in the overrun mode. At this time at the latest, the EGR valve could be closed to ensure the restart of engine combustion. When a new load request is made by the driver, but is not known.

Due to the bypass line according to the invention a regeneration of the particulate filter in the EGR line is possible even when the EGR valve is closed. The bypass line branches off after the particle filter and opens when using a turbocharger preferably after the turbine outlet in the exhaust pipe.

When the bypass line is opened, the part of the exhaust gas flow passed through the exhaust gas turbine is reduced. This is especially the case when the pressure drop across the turbocharger is greater than that across the EGR bypass path. A corresponding part of the exhaust gas flow can be guided through the particle filter and the bypass line with the EGR line closed. Thus, the regeneration of the particulate filter is favored in phases with closed EGR valve, for example in overrun operation.

In addition, compared to the sole flow through the open EGR valve guided by the particulate filter oxygen-rich exhaust stream can be significantly increased and the regeneration can be intensified.

It is no longer necessary to prevent the regeneration of the particulate filter before restarting the engine. The regeneration can last as long as it is necessary for a regeneration phase in the thrust of a built-in particulate filter in the main exhaust gas flow. The regeneration thus made possible can even exceed that of a particle filter installed downstream in the main exhaust gas flow in its effectiveness, since a higher thermal loading of the particulate filter takes place with the installation situation close to the engine, parallel to the turbocharger. As a result, the temperature of the particles in the particulate filter, for example in the phase of fuel cut-off, is higher and the regeneration more intense.

Beyond this improved regeneration of the particulate filter, further advantages are associated with the bypass line according to the invention.

By additionally switchable bypass line a part of the exhaust gas is passed to the exhaust gas turbine over. Thus, the bypass line also takes over the function of a wastegate valve; as it has been integrated in conventional turbochargers in the housing of the turbine so far. Thus, the bypass line is useful not only in overrun, but also under full load conditions of the gasoline engine when the exhaust gas energy exceeds the necessary drive energy for the compressor of the exhaust gas turbocharger. Also in this case, due to the im Exhaust residual oxygen contained and the high exhaust gas temperature of the particulate filter to be regenerated.

In addition, even more advantages go with the bypass line according to the invention, especially in the start or cold start phase of the engine.

The bypass line can also be opened in case of engine start. During and after the engine start or engine cold start, the turbocharger's turbocharging function is not yet present, since the exhaust gas energy is too low at these operating points. On the contrary. The exhaust gas turbine represents a flow resistance that impairs engine operation. With a deflection of the exhaust gas flow through the bypass line this disadvantage is reduced.

In addition to the amount of air required for the regeneration, it may be necessary to increase the exhaust gas temperature in order to achieve the exhaust gas temperature required for the regeneration. For this purpose, the following known in the prior art measures such as an ignition retard, a load point shift or a heating in question.

A coating of the particulate filter for the conversion of CO, HC and NOx in turn leads to the fulfillment of the tasks of a 3-way catalyst, thus reduced pollutant emissions in the intake system, which can additionally influence the combustion advantageous. The coating of the particulate filter acts in fired engine operation. The same applies to the filter effect of the particulate filter. In overrun operation, the regeneration of the particulate filter can take place. By combining particulate filtering and catalytic conversion of other incomplete combustion products, the exhaust gas recirculated to the engine has a high degree of purity both in terms of combustion products and particulates. This has a positive effect on the prevention of deposits in the intake system and on the combustion, and thus the pollutant emissions and the efficiency of the gasoline engine.

The exhaust gas catalyst is preferably placed downstream of the mouth of the bypass line. By the 3-way catalyst or the oxidation catalyst, the aforementioned advantages of reduced pollutant emissions are achieved in the main exhaust line.

In connection with the design and arrangement according to the invention, it may be advantageous if downstream of the particulate filter, a cooler is provided within the exhaust gas recirculation line. The cooler is spatially or at least thermally separated from the particulate filter, so that the particulate filter has high temperatures possible in wide engine operating conditions so that it regenerates at sufficient oxygen excess in the exhaust gas by oxidation of the filtered components. This achieves the largest possible working range of the particle filter for regeneration. The radiator is designed either as an exhaust air, exhaust gas engine cooling water or exhaust gas low-temperature cooling water cooler. In particular embodiments, a plurality of exhaust gas recirculation coolers, which may also be switchable, may be arranged in series or in parallel.

It can be advantageous, in particular, if the cooler has on the output side an exhaust gas target temperature Ta which is above the dew point of the substances contained in the exhaust gas, for example 250 °> = Ta> = 100 ° or 250 °> = Ta> = 105 °. The exhaust gas target temperature Ta is chosen so high that condensation of the water contained in the exhaust gas is prevented. This condition should apply to most of the operating conditions. Thus, excessive contamination of the EGR system can be prevented. Cooling to below 100 ° C takes place only in the second cooling stage after mixing of exhaust gas and fresh air in the intake or in the charge air line shortly before the engine enters. As a result, condensing water can enter directly into the engine combustion chamber and unfold by evaporation positive effect on the engine combustion. As explained below, despite the further cooling of the charge air, there is no risk of sooting for the charge air cooler close to the engine due to the particle filter.

It may advantageously be provided that the inlet line is formed upstream of the mouth of the exhaust gas recirculation line as a fresh air line and that at least one fresh air cooler and a fresh air throttle are provided in the fresh air line. By means of the fresh air cooler, a separate cooling of the fresh air before mixing with the exhaust gas can take place. Because the temperature level of the compressed fresh air at 150 ° C to 160 ° C but not so high, the separate cooling of the fresh air can also be omitted, in which case the fresh air-exhaust gas mixture as described below can be cooled together.

In addition, it may be advantageous if the fresh air cooler has on the output side a fresh air setpoint temperature Tf with 150 °> = Tf> = 60 °. The cooling power carried out in the fresh air system is in any case advantageous with regard to a cool as possible fresh air exhaust gas mixture.

It may also be advantageous if the inlet line is formed downstream of the mouth of the exhaust gas recirculation line as a charge air line and if at least one intercooler in the Charge air line is provided. The cleaning of the recirculated exhaust gas through the particulate filter ensures the effective use of the intercooler for the fresh air-exhaust mixture. A sputtering of the intercooler is prevented due to the use of the particulate filter. The effect that can be significantly reduced by the particulate filter in the EGR line soot particles and the exhaust gas temperature in high load operation can be enhanced by the intensive EGR and charge air cooling so far that the exhaust gas temperature can drop to the level of diesel engines or the Intake temperature before entering the cylinder can drop to the level of gasoline engines without EGR. As a result, the tendency to knock the gasoline engine drops significantly and it can be achieved significant fuel consumption improvements. This is achieved by the two- or three-stage cooling of the intake air charge by the EGR cooler, the intercooler and possibly the fresh air cooler using the different temperature levels.

The branching of the EGR line upstream of the turbine ensures higher exhaust gas temperatures, which have an overall positive effect on the particle filter regeneration and the pollutant reduction. The mouth downstream of the compressor has the advantage that the controlled system is shorter. This combination of branching upstream of the turbine and downstream of the compressor is referred to as high pressure EGR (HD-EGR). However, a sufficiently high pressure gradient between the exhaust system and the intake system may not be available for supplying the desired amount of recirculated exhaust gas in all desired operating states. In the event that additional cooling of the recirculated exhaust gas is required, the purified exhaust gas can also be fed to the intake system after the compressor and before the intercooler. Thus, the exhaust gas is cooled not only in the EGR cooler, but also in the intercooler. Also conceivable is an arrangement in which the intercooler is designed so effectively that no EGR cooler in the EGR line is required for the recirculated exhaust gas.

The branch upstream of the turbine in combination with the upstream orifice of the compressor is referred to as maximum pressure EGR (MD-EGR) and ensures a large pressure differential within the EGR line even for larger required EGR rates. However, this makes the controlled system longer than in the case of the HD EGR and the compressor and the turbine must be adapted to the changed mass flow rates if necessary.

The branch downstream of the turbine in combination with the upstream orifice of the compressor is referred to as low pressure EGR (ND-EGR).

For this purpose, it may be advantageous if the charge air cooler on the output side has a charge air setpoint temperature Tu with Tu <= 60 °. Due to the intensive cooling of the charge air, the exhaust gas temperature of the gasoline engine can be reduced to the level of diesel engines (about 850 ° C). This has a very positive effect on the tendency to knock the gasoline engine and significant improvements in fuel consumption are possible.

It can also be advantageous if an EGR valve is provided in the exhaust gas recirculation line, via which operating point a waste gas mass flow within the exhaust gas recirculation line can be set. The EGR valve is advantageously placed downstream of the particulate filter. In overrun phases of the engine, the EGR valve can be used to influence the regeneration of the particulate filter via the amount of recirculated fresh air. Positioning in front of the particle filter leads to increased contamination of the EGR valve and is only considered in exceptional cases. In addition, it may be advantageous if the EGR valve is provided downstream of the radiator. Thus, this is protected from excessive temperature stress.

It may also be advantageous if a bypass throttle valve is provided in the bypass line, via the operating point-dependent an exhaust gas mass flow within the bypass line is adjustable.

It may also be advantageous if a further exhaust gas recirculation line is provided with a further EGR valve which branches off at the exhaust gas recirculation line or which branches off at the bypass line, wherein the further exhaust gas recirculation line opens in the inlet line upstream of the compressor. Thus, as an alternative to the EGR line, the further EGR line can be used. Both EGR lines can also be used together.

Since the recirculated exhaust gas is removed before the catalyst of the exhaust system, instead of a coated particulate filter, an additional 3-way catalyst or an oxidation catalyst can be integrated in the exhaust gas recirculation line. However, these catalysts represent a further component component, which is alternatively avoidable with a catalytically coated particle filter. In any case, the oxidation of pollutant components leads to the development of heat and thus to the heating of the downstream particulate filter. This extends the use of autonomous regeneration of the particulate filter in overrun mode to further operating states.

In addition, it can be provided a device for introducing secondary air over the Secondary air in the exhaust gas recirculation line and / or in the bypass line and a corresponding device for this. The secondary air can also be introduced into the exhaust pipe upstream of the exhaust gas recirculation line and / or upstream of the bypass line. A use of secondary air, with which the exhaust pipe and thus the particulate filter are supplied with additional oxygen for regeneration, may also be advantageous. However, it is important to ensure that the additional air flow is actually passed through the particulate filter. Therefore, when using the secondary air pump, the EGR valve should be open. Additionally or alternatively, the bypass line may be open. However, when the EGR valve is closed, the bypass line must be open. For this purpose, a common introduction point for the secondary air can be used near the exhaust valve in the cylinder head exit channel. The secondary air can be provided via a separate secondary air pump or by means of the charge air compressor, if the existing pressure levels ensure this.

The object is also achieved by using an exhaust system and / or a gasoline engine with an exhaust gas routing system for the method described above.

• 1 eine Prinzipskizze einer HD-AGR mit Bypass-Leitung;
• 2 eine Prinzipskizze einer MD-AGR mit Bypass-Leitung;
• 3 Prinzipskizze einer kombinierten HD- und MD-AGR mit Bypass-Leitung.

Further advantages and details of the invention are explained in the patent claims and in the description and illustrated in the figures. Show it:

• 1 a schematic diagram of a HD EGR with bypass line;
• 2 a schematic diagram of an MD-EGR with bypass line;
• 3 Schematic diagram of a combined HD and MD EGR with bypass line.

In all principle sketches after the 1 - 3 is shown an exhaust control system 1 (EGR system), which in the exhaust and charge air system of a gasoline engine 2 with exhaust manifold 2.1 and intake manifold 2.2 as well as with exhaust gas turbine 3 and charge air compressor 4 is integrated. The exhaust and charge air system has one to the exhaust manifold 2.1 of the gasoline engine 2 connected exhaust pipe 2.3 on, in which the turbine 3 is integrated. At the end of the exhaust pipe 2.3 leaves exhaust 7 the exhaust control system 1 and flows into the other, not shown exhaust route. In addition, one to the intake manifold 2.2 of the gasoline engine 2 connected inlet line 2.4 provided in the the compressor 4 is integrated. The inlet pipe 2.4 is via an unillustrated air supply system with fresh air 8th provided. In addition, at least one exhaust gas recirculation line 1.1a (EGR line) with an EGR valve 1.3 provided at the exhaust pipe 2.3 branches off and in the inlet line 2.4 empties.

In addition to this is a bypass line 1.1b provided, which is also on the exhaust pipe 2.3 branches off and downstream of the turbine 3 in the exhaust pipe 2.3 empties. It is irrelevant whether the bypass line 1.1b at the exhaust gas recirculation line 1.1a branches off or whether the exhaust gas recirculation line 1.1a at the bypass line 1.1b branches. The bypass line 1.1b has a bypass throttle 1.4 for regulating the gas mass flow.

In the AGR line 1.1a is a particle filter 1.2 . 1.2x arranged, which is the recirculated or recirculated exhaust gas 7 filters. The particle filter 1.2x may be coated and perform the tasks of a 3-way catalyst or at least one oxidation catalyst. Alternatively, the particulate filter 1.2 also be uncoated. In this case, an exhaust gas catalyst 5 * become necessary, for example, upstream of the particulate filter 1.2 is placed (shown in phantom) to a catalytic purification of the recirculated exhaust gas 7 to ensure.

Further, in the EGR line 1.1a downstream of the particulate filter 1.2 . 1.2x at least one EGR cooler 1.6 intended. Downstream of the respective EGR cooler 1.6 or in front of the mouth into the inlet line 2.4 is an EGR valve 1.3 for regulating the mass flow within the EGR line 1.1a placed.

In the inlet pipe 2.4 is a charge air or fresh air throttle 2.6 upstream of the discharge point of the exhaust gas recirculation line 1.1a in the inlet pipe 2.4 intended. This part of the inlet pipe 2.4 is also called fresh air pipe 2.4a designated. Inside the fresh air line 2.4a is also a charging or fresh air cooler 6 intended.

Downstream of the turbine 3 is in the exhaust pipe 2.3 a catalyst 5 provided, which is designed as a 3-way catalyst or as an oxidation catalyst. Regardless of the embodiments described below, the particular catalyst used may be 5 basically be a 3-way catalyst or an oxidation catalyst. An oxidation catalyst 5 comes especially into consideration when it comes to a lean-burn gasoline engine 2 is.

In addition to the EGR cooler 1.6 and to the fresh air cooler 6 is in the inlet line 2.4 downstream of the point of introduction of the exhaust gas recirculation line 1.1a a charge air cooler 2.5 placed. This part of the inlet pipe 2.4 downstream of the point of introduction of the exhaust gas recirculation line 1.1a is also called charge air line 2.4b designated.

In addition, the exhaust side is a device 9 for introducing secondary air in the cylinder head or in the exhaust manifold 2.1 or in the exhaust pipe 2.3 intended.

Basically, a distinction is made between three variants of the exhaust gas recirculation, depending on the diversion of the EGR line 1.1a from the exhaust pipe 2.3 and mouth of the EGR pipe 1.1a in the inlet pipe 2.4 ,

The combination of branching of the EGR line 1.1a upstream of the turbine 3 and mouth of the EGR pipe 1.1a downstream of the compressor 4 is referred to as high pressure EGR (HD-EGR).

The combination of branching of the EGR line 1.1a upstream of the turbine 3 and mouth of the EGR pipe 1.1a upstream of the compressor 4 is referred to as maximum pressure EGR (MD-EGR).

The combination of branching of the EGR line 1.1a downstream of the turbine 3 and mouth upstream of the compressor 4 is referred to as low pressure EGR (ND-EGR).

In the diagram after 1 a HD EGR is shown formed by the EGR pipe 1.1a that are upstream of the turbine 3 branches off and the downstream of the compressor 4 empties. The mouth is downstream of the charge air or fresh air throttle 2.6 ,

To 2 is an MD-AGR trained.

In the embodiment according to 3 are combined a HD-AGR and an MD-AGR. At the bypass line 1 , 1b branches downstream of the radiator 1.6 an additional EGR line 1.1c with another EGR valve 1.5 from. In the AGR line 1.1c is an additional EGR valve 1.5 intended. The EGR line 1.1c flows into the inlet pipe 2.4 upstream of the compressor 4 , The EGR cooler 1.6 * Alternatively, it can also be downstream of the branch for the further EGR line 1.1c be positioned. The bypass line 1.1b can also be downstream of the catalyst 5 (shown in dashed lines) open. This also applies to the embodiments according to 1 and 2 ,

LIST OF REFERENCE NUMBERS

1

Exhaust system / exhaust control system

1.1a

Exhaust gas recirculation line, EGR line

1.1a / b

EGR line / bypass line

1.1b

Bypass line

1.1c

further exhaust gas recirculation line, EGR line

1.2

particulate Filter

1.2x

Particle filter, coated

1.3

AGR valve

1.4

Bypass throttle from 1.1b

1.5

another EGR valve

1.6

Radiator, EGR cooler

1.6 *

Cool alternative position

2

gasoline engine

2.1

exhaust manifold

2.2

intake manifold

2.3

exhaust pipe

2.4

inlet line

2.4a

Fresh air line

2.4b

Turbo pipe

2.5

Intercooler

2.6

Charge air throttle, fresh air throttle

3

turbine

4

Compressor, charge air compressor

5

Catalyst, 3-way catalyst, oxidation catalyst

5 *

Catalytic converter, 3-way or oxidation catalyst, alternatively

6

Intercooler, fresh air cooler

7

exhaust

8th

fresh air

9

Device for introducing secondary air

Claims (13)

An exhaust control system (1) for a gasoline engine (2) for use in a method according to any one of Claims 11 to 13 with an exhaust pipe (2.3) which can be connected to an exhaust manifold (2.1) of the gasoline engine (2), with an inlet pipe (2.4) which can be connected to an intake manifold (2.2) of the gasoline engine (2) and with a turbine (3) arranged in the exhaust gas pipe (2.3) ), characterized in that at least one exhaust gas recirculation line (1.1a, 1.1c) is provided with an EGR valve 1.3, which opens in the inlet line (2.4), and that the exhaust line (2.3) at least one bypass line (1.1b) having a bypass throttle valve 1.4, which opens downstream of the turbine (3) in the exhaust pipe (2.3), wherein a) the exhaust gas recirculation line (1.1a) branches off upstream of the turbine (3) and the bypass line (1.1b) at the Exhaust gas recirculation line (1.1a) branches off or b) the bypass line (1.1b) branches off upstream of the turbine (3) and the exhaust gas recirculation line (1.1a) branches off at the bypass line (1.1b), wherein c) in the exhaust gas recirculation line (1.1a) or in the bypass line Line (1.1b) upstream of the exhaust gas recirculation line (1.1a) or in the exhaust pipe (2.3) upstream of the exhaust gas recirculation line (1.1a) at least one particulate filter (1.2x) is arranged, wherein the at least one particulate filter (1.2x) a catalytically active coating for Conversion of CO, HC and NOx, wherein downstream of the turbine (3) designed as a 3-way catalyst exhaust gas catalyst (5) is provided. Exhaust gas routing system (1) according to one of the preceding claims, characterized in that downstream of the particulate filter (1.2x) a cooler (1.6) is provided within the exhaust gas recirculation line (1.1a). Emission control system (1) according to Claim 2 , characterized in that the cooler (1.6) on the output side has an exhaust gas target temperature Ta, which is above the dew point of the substances contained in the exhaust gas. Emission control system (1) according to one of the preceding claims, characterized in that the inlet line (2.4) upstream of the mouth of the exhaust gas recirculation line (1.1a) is designed as a fresh air line (2.4a) and that at least one fresh air cooler (6) and a fresh air throttle valve ( 2.6) are provided in the fresh air line (2.4a). Exhaust gas routing system (1) according to one of the preceding claims, characterized in that the inlet line (2.4) downstream of the mouth of the exhaust gas recirculation line (1.1a) is designed as a charge air line (2.4b) and that at least one charge air cooler (2.5) in the charge air line (2.4b ) is provided. Emission control system (1) according to one of the preceding claims, characterized in that via the EGR valve (1.3) in the exhaust gas recirculation line (1.1a) operating point-dependent exhaust gas mass flow within the exhaust gas recirculation line (1.1a) is adjustable. Emission control system (1) according to one of the preceding claims, characterized in that via the bypass throttle valve (1.4) in the bypass line (1.1b) operating point-dependent exhaust gas mass flow within the bypass line (1.1b) is adjustable. Exhaust gas routing system (1) according to one of the preceding claims, characterized in that a further exhaust gas recirculation line (1.1c) with a further EGR valve (1.5) is provided which branches off at the exhaust gas recirculation line (1.1a) or at the bypass line ( 1.1b) branches off, wherein the further exhaust gas recirculation line (1.1c) in the inlet line (2.4) opens upstream of a compressor (4). Exhaust gas routing system (1) according to one of the preceding claims, characterized in that a device (9) for introducing secondary air is provided, via the secondary air into the exhaust gas recirculation line (1.1a) and / or in the bypass line (1.1b) can be introduced , Exhaust system and / or gasoline engine (2) with an exhaust gas routing system (1) according to one of the preceding claims. Method for operating a gasoline engine (2) with an exhaust gas routing system (1) or an exhaust gas system according to one of the preceding claims, characterized in that a) during overrun of the gasoline engine (2) at least partially closed EGR valve (1.3) at least a part of Exhaust gas flow through the particulate filter (1.2x) and through the bypass line (1.1b) is performed, wherein a regeneration of the particulate filter (1.2x) is performed; b) during and after the start of the gasoline engine (2) at least partially closed EGR valve (1.3) by opening the bypass throttle valve (1.4) at least a portion of the exhaust gas flow through the particulate filter (1.2x) and through the bypass line ( 1.1b) is guided past the turbine (3) until a predetermined exhaust gas pressure is reached; c) in full-load operation of the gasoline engine (2) or at least full load close the bypass line (1.1b) is used as wastegate for passing at least part of the exhaust gas flow to the turbine (3) over, carried out a regeneration of the particulate filter (1.2x) becomes. Method according to Claim 11 , characterized in that when introducing secondary air through the device (9) a) the EGR valve (1.3) is opened and optionally exhaust gas (7) through the bypass line (1.1b) is performed or b) the EGR Valve (1.3) is closed and alternatively exhaust gas (7) through the bypass line (1.1b) is guided. Method according to Claim 11 or 12 , characterized in that the secondary air can also be introduced into the EGR line (1.1a / b).

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