DE102020126163A1 - Exhaust aftertreatment device with at least two catalytic converters, internal combustion engine with an exhaust aftertreatment device, motor vehicle with an internal combustion engine and method for operating an exhaust aftertreatment device - Google Patents

Abstract

The invention relates to an exhaust gas aftertreatment device for an internal combustion engine, with a first exhaust gas discharge duct, via which an exhaust gas flow can be discharged from at least one cylinder of the internal combustion engine, and with a first catalytic converter, which is coupled via a first exhaust gas duct of the exhaust gas aftertreatment device on the one hand to the first exhaust gas discharge duct and on the other hand is coupled to a second catalytic converter of the exhaust gas aftertreatment device. The exhaust gas aftertreatment device comprises a second exhaust gas duct, which is coupled to the first exhaust gas discharge duct and via which at least part of the exhaust gas flow can be fed to the second catalytic converter, bypassing the first catalytic converter, and a flow rate adjustment device, which exhaust gas is connected to the first exhaust gas discharge duct, the first exhaust gas duct and to the second exhaust gas duct connected is. The flow rate adjustment device can be adjusted between states in which the first catalytic converter can be supplied with different exhaust gas flow portions of the exhaust gas flow emerging from the first exhaust gas discharge channel. Further aspects of the invention relate to an internal combustion engine with an exhaust gas aftertreatment device and a method for its operation and a motor vehicle with an internal combustion engine.

Description

The invention relates to an exhaust gas aftertreatment device for an internal combustion engine. Further aspects of the invention relate to an internal combustion engine with an exhaust gas aftertreatment device, a motor vehicle with an internal combustion engine and a method for operating an exhaust gas aftertreatment device of an internal combustion engine.

Exhaust gas aftertreatment devices of this type are constantly gaining in importance in the course of exhaust gas legislation that is becoming ever more stringent. With the replacement of the NEDC (new European driving cycle) by so-called RDE test methods (RDE = real driving emissions), emissions such as nitrogen oxide emissions or the number of ultrafine particles emitted by a motor vehicle are measured in practical driving operation, i.e. in road traffic. In order to comply with such strict specifications, the functionality of exhaust gas aftertreatment devices over a particularly large map range of an internal combustion engine is important.

A well-known strategy for exhaust aftertreatment is to use multiple catalysts. An example of this is the DE 10 2010 032 363 A1 in which an internal combustion engine has a first row of cylinders and a second row of cylinders. The internal combustion engine includes a first exhaust manifold coupled to the first bank of cylinders, a second exhaust manifold coupled to the second bank of cylinders, a first pipe coupled to the first exhaust manifold and having a first catalyst installed therein, a second pipe coupled to the second exhaust manifold having a second catalytic converter installed therein and a turbocharger having first and second exhaust gas inlets coupled to the first and second pipes, respectively.

The object of the present invention is to provide an exhaust gas aftertreatment device, an internal combustion engine, a motor vehicle, and a method of the type mentioned at the outset, by means of which particularly effective exhaust gas aftertreatment is made possible.

This object is achieved by an exhaust gas aftertreatment device having the features of patent claim 1, by an internal combustion engine having the features of patent claim 8, by a motor vehicle having the features of patent claim 9, and by a method having the features of patent claim 10. Advantageous configurations with expedient developments of the invention are specified in the dependent claims.

A first aspect of the invention relates to an exhaust gas aftertreatment device for an internal combustion engine, with at least one first exhaust gas discharge channel, via which an exhaust gas flow can be discharged from at least one cylinder of the internal combustion engine, and with at least one first catalytic converter, which on the one hand is at least indirectly connected via a first exhaust gas channel of the exhaust gas aftertreatment device to the first exhaust gas discharge channel is coupled exhaust conducting and on the other hand is at least indirectly coupled to at least one second catalytic converter of the exhaust gas aftertreatment device exhaust conducting. The first exhaust gas discharge channel can, for example, comprise an exhaust manifold or be designed as an exhaust manifold.

According to the invention, it is provided that the exhaust gas aftertreatment device comprises a second exhaust gas duct, which is at least indirectly coupled to the first exhaust gas discharge duct in order to conduct exhaust gas, via which at least part of the exhaust gas flow can be fed to the at least one second catalytic converter, bypassing the at least one first catalytic converter, and at least one flow rate adjustment device, which is at least indirectly connected to the first exhaust gas discharge duct, the first exhaust gas duct and the second exhaust gas duct and which can be adjusted at least between two states in which the first catalytic converter can be supplied with different exhaust gas flow components of the exhaust gas flow emerging from the first exhaust gas discharge duct via the flow rate adjustment device is. This is advantageous because by adjusting the flow adjustment device, a targeted dosing of the exhaust gas flow components that are to be fed to the first catalytic converter can take place. By adjusting the flow rate setting device in the different states, the respective catalytic converters (first catalytic converter, second catalytic converter) can thus be subjected to different exhaust gas mass flows, as a result of which pollutant conversion can take place as required and the respective catalytic converters can be heated in a targeted manner in order to achieve a respective light-off temperature (light-off temperature). temperature) of the catalysts. The first exhaust gas duct of the exhaust gas aftertreatment device can be coupled to the first exhaust gas discharge duct, for example, by means of the flow rate adjustment device and thereby indirectly. Different exhaust gas flow components can be supplied to the first catalytic converter, for example via the flow rate adjustment device and the first exhaust gas channel. the States can generally also be referred to as switching positions.

The first catalytic converter can be supplied with exhaust gas over a shorter distance than the second catalytic converter. In other words, exhaust gas can travel a shorter route to the first catalytic converter than to the second catalytic converter. Accordingly, the first catalytic converter can be referred to as a so-called close-coupled catalytic converter, and although the second catalytic converter is also arranged close to the engine, it is at a greater distance from the internal combustion engine than the first catalytic converter.

The invention is based on the finding that by adjusting between the at least two states, the exhaust gas flow can be distributed to the respective catalytic converters, i.e. the first catalytic converter and the second catalytic converter, as required and in a manner favorable to flow, so that depending on the load point (low-load operation, partial-load operation, full-load operation) the internal combustion engine can be guided through the first catalytic converter in each case different exhaust gas flow proportions. The flow adjustment device can be used to adjust the exhaust gas flow proportions in a particularly flexible manner, so that, for example, the adjustment can be made on the one hand as a function of the most complete possible pollutant conversion using the respective catalytic converters and on the other hand a respective flow through the respective catalytic converters with particularly low flow losses and with particularly low exhaust gas back pressure.

In an advantageous development of the invention, the first catalytic converter is designed for exhaust gas aftertreatment of a smaller maximum exhaust gas mass flow than the second catalytic converter. This is advantageous because the first catalytic converter can be heated to its light-off temperature more quickly than the second catalytic converter, which on the one hand enables particularly rapid pollutant conversion shortly after a cold start of the internal combustion engine and on the other hand a particularly flexible conversion , Streamlined adjustment of the various exhaust gas flow components is made possible. The expression maximum exhaust gas mass flow is to be understood as meaning an exhaust gas mass flow of the exhaust gas flow which, if exceeded, causes impermissibly high pollutant emissions to occur downstream of the respective catalytic converter (e.g. the first catalytic converter), i.e. despite exhaust gas aftertreatment by this catalytic converter.

In other words, the first catalyst can be smaller than the second catalyst. The first catalytic converter can preferably be designed to convert the exhaust gas flow during low-load operation and during partial-load operation of the internal combustion engine. In contrast to the first catalytic converter, the second catalytic converter can be configured and thus designed for converting the exhaust gas flow when the internal combustion engine is operating under full load.

In a further advantageous development of the invention, the first exhaust gas duct is coupled to the second exhaust gas duct upstream of the second catalytic converter. This is advantageous because the exhaust gas flow components emerging from the first catalytic converter can also be fed to the second catalytic converter and can be used to heat the second catalytic converter to its light-off temperature. Another advantage is that in the event of damage or failure of the first catalytic converter, the entire exhaust gas flow can still be routed through the second catalytic converter for exhaust gas aftertreatment, so that an impermissible flow around, i.e. bypassing, the catalytic converters can be avoided. In summary, the entire exhaust gas flow can flow through the second catalytic converter, which means that the second catalytic converter can be heated particularly quickly on the one hand and particularly comprehensive exhaust gas aftertreatment can be achieved by the second catalytic converter on the other.

For this purpose, the first exhaust gas duct can open upstream of the second catalytic converter, ie upstream of the second catalytic converter in the flow direction of the exhaust gas flow, for example into the second exhaust gas duct or the second exhaust gas duct into the first exhaust gas duct. This allows the entire exhaust flow to flow through the second catalytic converter.

Particularly preferably, the entire exhaust gas flow can be guided through the second catalytic converter in all states of the flow adjustment device. In other words, it can preferably be provided that in all possible states of the flow adjustment device it can be ensured that at least the second catalytic converter can be acted upon by the entire exhaust gas flow. This makes it possible to avoid inadvertently diverting the flow of exhaust gas around the catalytic converters in a particularly simple manner.

In a further advantageous development of the invention, the first catalytic converter and the second catalytic converter are designed in the same way. Similar is to be understood here as meaning that both catalysts are assigned to the same type of catalyst. For example, both the first catalytic converter and the second catalytic converter can be designed as a 3-way catalytic converter. This is an advantage, as this results in a similar Exhaust gas aftertreatment can be carried out by the respective catalysts, so that no adjustment of a combustion air ratio during operation of the internal combustion engine has to be carried out on the respective type of catalyst. In addition, the second catalytic converter can thus be used effectively for redundant exhaust gas after-treatment, whereby exhaust gas after-treatment by the second catalytic converter can continue to be ensured in the event of a failure of the first catalytic converter.

In a further advantageous development of the invention, the exhaust gas aftertreatment device comprises at least one exhaust gas turbocharger, which is coupled via the second exhaust gas duct on the one hand to the flow adjustment device and on the other hand to the second catalytic converter in an exhaust gas-conducting manner. This is advantageous because, on the one hand, the exhaust gas turbocharger can ensure a particularly effective increase in the output of the internal combustion engine and, on the other hand, the exhaust gas turbocharger can be used to increase an exhaust gas back pressure of the exhaust gas flow upstream of the exhaust gas turbocharger, for example in the first exhaust gas discharge duct and the first exhaust gas duct, whereby the the first catalytic converter is thus supplied with a correspondingly large proportion of the exhaust gas flow emerging from the first exhaust gas discharge duct, and the first catalytic converter can thus be heated particularly quickly to its light-off temperature.

The flow rate setting device can preferably be designed as a wastegate, ie as an exhaust gas bypass valve, for setting, in particular regulating, a boost pressure that can be built up in an intake duct of the internal combustion engine by means of the exhaust gas turbocharger. This is advantageous because the flow adjustment device thereby has a particularly high level of functionality, in other words it can assume several functions, namely setting the exhaust gas flow components on the one hand and setting the charging pressure on the other.

In a further advantageous development of the invention, the at least one exhaust gas turbocharger is designed as a multiflow exhaust gas turbocharger. This is advantageous because the multi-flow exhaust gas turbocharger allows exhaust gas to be applied in a targeted manner to a turbine of the exhaust gas turbocharger, as a result of which the exhaust gas turbocharger can be operated with improved operating characteristics.

In a further advantageous development of the invention, a first flow of the multi-flow exhaust gas turbocharger is coupled to the second exhaust gas duct and a second flow of the multi-flow exhaust gas turbocharger is coupled in an exhaust gas-conducting manner to a third exhaust gas duct of the exhaust gas aftertreatment device, via which a second exhaust gas stream can be discharged from at least a second cylinder of the internal combustion engine. wherein the third exhaust gas duct is coupled at least indirectly to the flow adjustment device on the one hand and at least indirectly to the second catalytic converter on the other hand. This is advantageous because it allows a high degree of variability to be achieved when the exhaust gas aftertreatment device is operated. A major advantage is that the exhaust gas turbocharger can be supplied with exhaust gas in a particularly targeted manner using the second exhaust gas duct and the third exhaust gas duct and via the first flow and the second flow, as a result of which an improved response behavior of the exhaust gas turbocharger can be achieved. The third exhaust gas duct can preferably be coupled directly to the flow rate adjustment device. Irrespective of this, the third exhaust gas duct can preferably be coupled directly to the second catalytic converter. Provision can particularly preferably be made for the third exhaust gas duct to be coupled, bypassing the first catalytic converter, on the one hand at least indirectly, preferably directly, to the flow adjustment device and on the other hand at least indirectly, preferably directly, to the second catalytic converter. As a result, the exhaust gas aftertreatment device can be operated in a particularly variable manner.

A second aspect of the invention relates to an internal combustion engine with an exhaust gas aftertreatment device according to the first aspect of the invention. A particularly effective exhaust gas aftertreatment can take place in this internal combustion engine.

A third aspect of the invention relates to a motor vehicle with an internal combustion engine according to the second aspect of the invention. The motor vehicle comprising the internal combustion engine can be operated with a particularly effective exhaust gas aftertreatment.

A fourth aspect of the invention relates to a method for operating an exhaust gas aftertreatment device according to the first aspect of the invention, in particular an internal combustion engine according to the second aspect of the invention, in which the exhaust gas flow is discharged from the at least one cylinder via the at least one first exhaust gas discharge channel during operation of the internal combustion engine and the at least one flow adjustment device is supplied and in which different states of the at least one flow adjustment device depending on different operating states of the internal combustion engine, the at least one first catalytic converter and/or the at least one second catalytic converter adjusted and thereby the at least one first catalyst via the at least one flow adjustment device from each other, depending on the states exhaust gas flow portions are supplied. A particularly effective exhaust gas aftertreatment can take place with this method.

The operating states of the internal combustion engine can include cold start operation, operation at operating temperature, a full load requirement when the internal combustion engine is cold started, a full load requirement when the internal combustion engine is at operating temperature, and/or the internal combustion engine is idling, to name just a few examples. In this case, cold start operation corresponds to an operating state of the internal combustion engine in which the respective operating media, for example cooling water or engine oil of the internal combustion engine, have not yet reached their respective target operating temperature. For example, the target operating temperature of cooling water can be between 85° C. and 90° C. inclusive. The target operating temperature of engine oil can be, for example, between 80° C. and 120° C. inclusive. As soon as the internal combustion engine is at operating temperature, that is to say in other words operation of the internal combustion engine at operating temperature is enabled, the respective operating media have reached their respective target operating temperatures.

The operating states of the second catalytic converter can be cold operation of the second catalytic converter, in which the light-off temperature of the second catalytic converter has not yet been reached, and normal operation of the second catalytic converter, in which the light-off temperature has been reached and thus the pollutant conversion is complete Exhaust aftertreatment can be done by means of the second catalyst include.

The preferred embodiments presented in relation to one of the aspects and their advantages apply correspondingly to the respective other aspects of the invention and vice versa.

The features and combinations of features mentioned above in the description and the features and combinations of features mentioned below in the description of the figures and/or shown alone in the figures can be used not only in the combination specified in each case, but also in other combinations or on their own, without going beyond the scope of the leave invention.

Further advantages, features and details of the invention result from the claims, the following description of preferred embodiments and with reference to the drawings.

• 1 eine schematische Darstellung eines Kraftfahrzeugs mit einer Verbrennungskraftmaschine, welche als Saugmotor ausgebildet ist und eine Abgasnachbehandlungseinrichtung mit zumindest zwei Katalysatoren und einer Durchflusseinstellungsvorrichtung umfasst, mittels welcher dem ersten Katalysator in verschiedenen Zuständen der Durchflusseinstellungsvorrichtung jeweils voneinander verschiedene Abgasstrom-Anteile eines aus einem Abgasabführungskanal austretenden Abgasstroms zuführbar sind;
• 2 eine schematische Darstellung des Kraftfahrzeugs mit der Verbrennungskraftmaschine und einer weiteren Variante der Abgasnachbehandlungseinrichtung, bei welcher die Abgasnachbehandlungseinrichtung zusätzlich einen Abgasturbolader umfasst um die Verbrennungskraftmaschine mit verdichteter Luft zu betreiben;
• 3 eine weitere schematische Darstellung des Kraftfahrzeugs mit der Verbrennungskraftmaschine und einer weiteren Variante der Abgasnachbehandlungseinrichtung, bei welcher die Abgasnachbehandlungseinrichtung zwei Abgasturbolader und zwei Durchflusseinstellungsvorrichtungen umfasst und die jeweiligen Abgasturbolader mit verschiedenen Zylindern der Verbrennungskraftmaschine abgasleitend gekoppelt sind; und
• 4 eine weitere schematische Darstellung des Kraftfahrzeugs mit der Verbrennungskraftmaschine und einer weiteren Variante der Abgasnachbehandlungseinrichtung, bei welcher die jeweiligen Abgasturbolader jeweils abgasleitend mit sämtlichen Zylindern der Verbrennungskraftmaschine koppelbar sind, wobei sämtliche Abgasströme über die Durchflusseinstellungsvorrichtungen dem ersten Katalysator zuführbar sind.

The invention is explained again below using a specific exemplary embodiment. For this shows:

• 1 a schematic representation of a motor vehicle with an internal combustion engine, which is designed as a naturally aspirated engine and includes an exhaust gas aftertreatment device with at least two catalytic converters and a flow rate adjustment device, by means of which the first catalytic converter can be supplied with different exhaust gas flow components of an exhaust gas flow emerging from an exhaust gas discharge duct in different states of the flow rate adjustment device ;
• 2 a schematic representation of the motor vehicle with the internal combustion engine and a further variant of the exhaust gas aftertreatment device, in which the exhaust gas aftertreatment device additionally comprises an exhaust gas turbocharger in order to operate the internal combustion engine with compressed air;
• 3 a further schematic representation of the motor vehicle with the internal combustion engine and a further variant of the exhaust gas aftertreatment device, in which the exhaust gas aftertreatment device comprises two exhaust gas turbochargers and two flow adjustment devices and the respective exhaust gas turbochargers are coupled to different cylinders of the internal combustion engine in an exhaust gas-conducting manner; and
• 4 a further schematic representation of the motor vehicle with the internal combustion engine and a further variant of the exhaust gas aftertreatment device, in which the respective exhaust gas turbochargers can be coupled to all cylinders of the internal combustion engine in an exhaust gas-conducting manner, with all exhaust gas flows being able to be fed to the first catalytic converter via the flow rate adjustment devices.

1 shows a schematic representation of a motor vehicle K with an internal combustion engine 100, which is shown in FIG 1 variant shown is designed as a naturally aspirated engine and can be operated. Internal combustion engine 100 includes a plurality of cylinders 102, 104, which are assigned respective combustion chambers, in which a fuel-air mixture is burned and energy released thereby is used to move respective pistons, which are assigned to respective cylinders 102, 104 and are not shown in detail here can. The pistons come with one too not further shown crankshaft of the internal combustion engine 100 coupled so that the crankshaft can be driven as a result of moving the pistons. In the present case, the internal combustion engine 100 comprises three cylinders 102, which can form a cylinder group, and three further, second cylinders 104, which can form a second cylinder group, merely by way of example.

During operation of the internal combustion engine 100, the fuel-air mixture is intermittently ignited in the respective combustion chambers of the respective cylinders 102, 104. In order to supply internal combustion engine 100 with air, the air is first sucked in as intake air 116 from the surroundings of motor vehicle K and internal combustion engine 100 and conducted through an intake silencer 114 and an intake duct 112 to an intercooler 106 of internal combustion engine 100. The air (intake air 116) cooled by the intercooler 106 reaches a collector 108 via the intake duct 112 and a throttle flap 110 of the internal combustion engine 100, from which the air is distributed to the individual cylinders 102, 104. The combustion chambers are intermittently opened and closed via respective gas exchange valves, namely intake valves and exhaust valves (not shown here) which are assigned to the respective cylinders 102, 104, so that the air can enter the combustion chambers or (after combustion of the air-fuel mixture has taken place) ) exhaust gas can escape from the combustion chambers.

The cylinders 102, 104 can be arranged in series, as in all variants according to FIG 1 until 4 is shown. As an alternative to this, the cylinders 102 of a first cylinder bank and the cylinders 104 of a second cylinder bank of the internal combustion engine 100 arranged at an angle to the first cylinder bank can be arranged, which is not further shown here. The respective cylinder banks can thus together form a V shape, and internal combustion engine 100 can accordingly be designed as a V engine.

The cylinders 102 are connected to one another via a first exhaust gas discharge duct 12 of the exhaust gas aftertreatment device 10 , whereas the cylinders 104 are connected to one another via a second exhaust gas discharge duct 14 of the exhaust gas aftertreatment device 10 . The first exhaust gas discharge duct 12 can be designed as an exhaust manifold, after which the first exhaust gas discharge duct 12 can also be referred to as the first exhaust gas manifold. The second exhaust gas discharge channel 14 can also be designed as an exhaust manifold, after which the second exhaust gas discharge channel 14 can also be referred to as the second exhaust manifold.

An exhaust gas flow 16 indicated by an arrow can be discharged from the cylinders 102 of the internal combustion engine 100 via the first exhaust gas discharge channel 12 . A second exhaust gas flow 18 indicated by a further arrow can be discharged from the cylinders 104 of the internal combustion engine via the second exhaust gas discharge channel 14 .

The exhaust gas after-treatment device 10 comprises two catalytic converters 30, 40 close to the engine, which in the present case are designed as respective 3-way catalytic converters and are therefore of the same type. The first catalytic converter 30 can be supplied with exhaust gas over a shorter distance than the second catalytic converter 40. In other words, exhaust gas can be guided over a shorter distance to the first catalytic converter 30 than to the second catalytic converter 40. In addition, the first catalytic converter 30 is an exhaust gas aftertreatment device smaller maximum exhaust gas mass flow than the second catalytic converter 40. The first catalytic converter 30 is therefore smaller than the second catalytic converter 40. The exhaust gas aftertreatment device 10 can include a particle filter 80, which is embodied here as an Otto particle filter, and a rear silencer 86, which consists of the second Catalyst 40 exiting exhaust gas can be supplied via an exhaust gas duct 118 and, for example, a channel junction 120, as shown in FIG 1 and 2 can be seen, in which the second catalytic converter 40 can be coupled to the exhaust gas conducting channel 118 with the particle filter 80 and the particle filter 80 via the channel branch 120 to the rear silencer 86 exhaust gas conducting.

In general, the second catalytic converter 40 and the particle filter 80 can also have a common housing, as shown in FIG 3 and 4 is only indicated as an example.

3 and 4 also show that the exhaust gas aftertreatment device 10 can have, for example, two underfloor catalytic converters 82, 84, of which an underfloor catalytic converter 82, 84 can be arranged in each case in a branch of the exhaust gas-conducting duct branch 120. The underfloor catalytic converters 82, 84 can be downstream of the second catalytic converter 40 and the particulate filter 80 and upstream of the rear muffler 86, as also shown in FIG 3 and 4 is recognizable.

The first catalytic converter 30 is at least indirectly connected via a first exhaust gas channel 32 of the exhaust gas aftertreatment device 10, namely by means of a flow adjustment device 50 to the first Exhaust gas discharge channel 12 coupled exhaust conducting. On the other hand, the first exhaust gas duct 32 is at least indirectly coupled, namely by means of a second exhaust gas duct 42, to the second catalytic converter 40 in an exhaust gas-conducting manner. The first exhaust gas duct 32 upstream of the second catalytic converter 40 is coupled to the second exhaust gas duct 32 in an exhaust gas-conducting manner.

At least part of the exhaust gas flow 16 can be fed to the second catalytic converter 40 via the second exhaust gas duct 42 , which is coupled to the first exhaust gas discharge duct 12 in order to conduct exhaust gas, bypassing the first catalytic converter 30 . The flow adjustment device 50 of the exhaust gas after-treatment device 10 is connected to the first exhaust gas discharge channel 12 on the one hand and to the first exhaust gas channel 32 and the second exhaust gas channel 42 on the other hand. The flow rate adjustment device 50 can be adjusted between a plurality of states in which the first catalytic converter 30 can be supplied with different exhaust gas flow portions of the exhaust gas flow 16 exiting the first exhaust gas discharge channel 12 via the flow rate adjustment device 50 .

The exhaust gas aftertreatment device 10 also includes a third exhaust gas duct 72, which can be coupled to the second exhaust gas discharge duct 14, for example via the flow adjustment device 50. During operation of internal combustion engine 100 , second exhaust gas stream 18 can exit from other, second cylinders 104 and can be fed at least indirectly to second catalytic converter 40 via third exhaust gas duct 72 , bypassing first catalytic converter 30 . For this purpose, the third exhaust gas duct 72 is coupled at least indirectly, but in the present case directly, to the flow adjustment device 50 on the one hand and at least indirectly to the second catalytic converter 40 on the other hand.

Based on the in 2 , 3 and 4 variants shown, it can be seen that exhaust gas aftertreatment device 10 has at least one exhaust gas turbocharger 60 (as in 2 shown) may include. The exhaust gas turbocharger 60 is coupled via the second exhaust gas duct 42 on the one hand to the flow adjustment device 50 and on the other hand to the second catalytic converter 40 in an exhaust gas-conducting manner. According to the variant 2 The exhaust gas turbocharger 60 shown is also designed as a multiflow exhaust gas turbocharger. A first flow 62 of the multi-flow exhaust gas turbocharger 60 is coupled to the second exhaust gas duct 42 and a second flow 64 of the multi-flow exhaust gas turbocharger 60 to the third exhaust gas duct 72 of the exhaust gas aftertreatment device 10 . A turbine wheel 66 of the exhaust gas turbocharger 60 can be subjected to exhaust gas via the two flows 62 , 64 . The turbine wheel 66 is coupled in a torque-proof manner to a compressor wheel 68 of the exhaust gas turbocharger 60 , so that the turbine wheel 66 driven by exhaust gas admission can in turn drive the compressor wheel 68 . The air (intake air 116) guided through the intake channel 112 can be compressed by means of the compressor wheel 68. The second exhaust gas stream 18 can be discharged from the (here three) second cylinders 104 via the third exhaust gas duct 72 . The third exhaust gas duct 72 is coupled on the one hand to the flow adjustment device 50 and on the other hand to the second catalytic converter 40 via the exhaust gas turbocharger 60 , more precisely via its second flow 64 , and via the second exhaust gas duct 42 .

In the method for operating the exhaust gas aftertreatment device 10 of the internal combustion engine 100 , the (first) exhaust gas stream 16 can be discharged from the cylinders 102 via the first exhaust gas discharge channel 12 during the operation of the internal combustion engine 100 and fed to the flow adjustment device 50 . In addition, when the internal combustion engine 100 is operating, the second exhaust gas flow 18 can be discharged from the (second) cylinders 104 via the second exhaust gas discharge channel 14 and fed to the flow adjustment device 50 . Depending on different operating states of internal combustion engine 100 and/or first catalytic converter 30 and/or second catalytic converter 40, different states of flow rate adjustment device 50 can be set and exhaust gas flow rates that are different from one another and dependent on the respective states can be transmitted to first catalytic converter 30 via flow rate adjustment device 50. Shares are supplied. The exhaust gas aftertreatment device 10 or the internal combustion engine 100 can include a control device (not shown) by means of which the various states of the flow adjustment device 50 can be set. The flow adjustment device 50 can be designed as a switchable valve or as a wastegate.

in the in 3 and 4 variants shown, the exhaust gas aftertreatment device 10 includes, in addition to the exhaust gas turbocharger 60, a further exhaust gas turbocharger 60A, which can also be referred to as a second exhaust gas turbocharger 60A. The second exhaust gas turbocharger 60A includes a turbine wheel 66A, which can also be referred to as the second turbine wheel 66A. In addition, the second exhaust-gas turbocharger 60A includes a compressor wheel 68A, which is coupled in a torque-proof manner to the turbine wheel 66A and can also be referred to as the second compressor wheel 68A. The air (intake air 116) guided through the intake channel 112 can also be compressed by means of the second compressor wheel 68A.

At the in 3 and 4 variants shown, the exhaust gas aftertreatment device 10 comprises a further flow adjustment device 50A, which can also be referred to as the second flow adjustment device 50A.

In the variant according to 3 is - in contrast to the variant according to 2 - provided that the third exhaust gas duct 72 is connected to the second exhaust gas turbocharger 60A instead of to the first exhaust gas turbocharger 60, so that the second exhaust gas flow 18 discharged via the second exhaust gas discharge duct 14 via the second flow adjustment device 50A and the third exhaust gas duct 72 to the second turbine wheel 66A of the second Exhaust gas turbocharger 60A can be supplied. A second additional exhaust gas duct 42A of exhaust gas aftertreatment device 10 is coupled to the second turbine wheel 66A in an exhaust gas-conducting manner on the one hand and opens out into the second exhaust gas duct 42 on the other hand. 3 FIG. 1 also shows that the exhaust gas aftertreatment device 10 in this variant can include a first additional catalytic converter 30A. The first additional catalytic converter 30A can be coupled via a first additional exhaust gas duct 32A of the exhaust gas aftertreatment device 10 on the one hand to the second additional exhaust gas duct 42 and on the other hand to the second flow adjustment device 50A. The second flow rate adjustment device 50A can also be designed and/or controllable in the same way as the flow rate adjustment device 50 . Accordingly, at the in 3 variant shown, a particularly flexible adjustment of the exhaust gas aftertreatment device 10 can be carried out.

In contrast to the in 3 shown variant includes the variant according to 4 no first auxiliary catalyst 30A. Instead, the exhaust gas aftertreatment device 10 comprises a fourth exhaust gas duct 74, which is connected on the one hand between the (first) flow adjustment device 50 and the first catalytic converter 30 to conduct the exhaust gas to the first exhaust gas passage 32 and on the other hand to conduct the exhaust gas to the second flow adjustment device 50A. This is advantageous because the second exhaust gas flow 18 can be routed particularly flexibly using the second flow adjustment device 50A, so that, for example, the entire second exhaust gas flow 18 can be routed to the first catalytic converter 30 or, alternatively, the entire second exhaust gas flow 18 can be routed to the second turbine wheel 66A.

Overall, the exhaust gas aftertreatment can be carried out using the at least two catalytic converters 30, 40 using the exhaust gas aftertreatment device 10, wherein the first catalytic converter 30 can be made smaller than the second catalytic converter 40. In addition, the first catalytic converter 30 can be arranged closer to the engine than the second catalytic converter 40. Through this configuration and arrangement of the respective catalytic converters 30, 40, pollutant conversion during a cold start and low-load operation of the internal combustion engine 100 and rapid heating of at least the first catalytic converter 30 can be achieved. The larger, second catalytic converter 40, which is a little further away, ensures the pollutant conversion at higher load points, for example in full-load operation, and at high speeds of the internal combustion engine 100.

With the appropriate arrangement and coupling of the catalytic converters 30, 40 and the flow rate adjustment device 50 and, if applicable, the second flow rate adjustment device 50A, depending on the load point of the internal combustion engine 100 and/or depending on the operating state of the corresponding first catalytic converter 30, 30A, the various states of the flow rate adjustment device(s) can be set ) 50, 50A can be varied in order to set the exhaust gas flow components to be fed to the first catalytic converter(s) 30, 30A in a particularly needs-based manner. The second catalytic converter 40 has exhaust gas applied to it and flows through it in all states of the flow rate adjustment device(s) 50, 50A, the second catalytic converter 40 being used in particular at high power of the internal combustion engine 100, for example in full-load operation and possibly in part-load operation for pollutant conversion (exhaust gas conversion). and in other words used for exhaust aftertreatment.

A major advantage of exhaust gas aftertreatment device 10 is that exhaust gas is applied to second catalytic converter 40 during operation of internal combustion engine 100 in all states of flow rate adjustment device 50 and/or flow rate adjustment device 50A. Even if the entire exhaust gas flow is guided through the first catalytic converter 30 and is completely converted using the first catalytic converter 30, exhaust gas still gets into the second catalytic converter 40 and heats it up. As a result, it can be avoided that the second catalytic converter 40 cools down during the operation of the internal combustion engine 100 and thereby cools down to a catalytic converter temperature which is below the light-off temperature of the second catalytic converter 40 . As a result, the second catalytic converter 40 not only serves as a fallback system, ie as a redundant exhaust gas aftertreatment device in the event of a failure of the first catalytic converter 30, but is also ready for use particularly quickly for exhaust gas aftertreatment if required.

In low-load operation, part-load operation and when cold starting the internal combustion engine 100 In connection with heating of the respective catalytic converters 30, 40, the presently smaller, first catalytic converter 30 can take over the function of pollutant conversion (exhaust gas conversion) and thus exhaust gas aftertreatment even before the second catalytic converter 40, which is larger than the first catalytic converter 30, especially since the first catalytic converter 30 starts up faster when heating up, and so that the light-off temperature of the first catalytic converter 30 is reached more quickly. In addition, there is little or no risk of the first catalytic converter 30 cooling down during low-load operation or part-load operation.

In low-load operation and/or in part-load operation, the flow rate adjustment device 50 or 50A can be adjusted to a first state of the states in which the turbine 66 or 66A is bypassed, i.e. exhaust gas is routed exclusively via the first exhaust gas channel 32 or 32A (see 2 and 3 ) or the fourth exhaust duct (see 4 ) he follows. This can prevent the exhaust gas turbocharger 60 or 60A from extracting heat from the exhaust gas, as a result of which the second catalytic converter 40 downstream of the first catalytic converter 30 or 30A can be heated particularly effectively.

In full-load operation, the flow rate adjustment device 50 or 50A can be adjusted into a further, second state of the states, in which the first catalytic converter 30 is bypassed and instead only the second catalytic converter 40 is flowed through. In this case, the exhaust gas is routed completely bypassing the first catalytic converter 30 or 30A and the respective turbine 66 or 66A is used to drive the respective compressor 68 or 68A and thus to compress the air (intake air 116). As a result, the internal combustion engine can be operated with a particularly high output at a stoichiometric combustion air ratio, also referred to as λ1 output.

By bypassing the first catalytic converter 30 or 30A, the latter can be protected from impermissibly high exhaust gas temperatures in full-load operation. In addition, for example, a load limitation of internal combustion engine 100 can take place by operating it with Miller control times, i.e. by early closing of the intake valves assigned to the respective cylinders 102, 104, small intake spread of the intake valves and/or small valve lift of the intake valves. As a result, a complete exhaust gas mass flow of the internal combustion engine 100 can be routed via the respective turbine 66 or 66A, bypassing the first catalytic converter 30 or 30A. Additionally or alternatively, the load limitation can also be achieved by reducing the opening of throttle valve 110 or by retarding the respective ignition angle (crank angle of the crankshaft of internal combustion engine 100 at which the fuel-air mixture in the respective cylinders 102, 104 is ignited) of the internal combustion engine 100 can be effected.

As already mentioned, the flow adjustment device 50, 50A can be designed as a wastegate, ie as an exhaust gas bypass valve. As an alternative to this, the flow adjustment device 50, 50A can also be designed as a switching valve. By reviewing 1 until 4 it can be seen that the exhaust gas aftertreatment device 10 functions independently of how the exhaust gas turbocharger 60 or the exhaust gas turbochargers 60, 60A are configured. At least one of the exhaust gas turbochargers 60, 60A can be designed as a multi-flow exhaust gas turbocharger (twin-scroll exhaust gas turbocharger), as a single-flow exhaust gas turbocharger (monoscroll exhaust gas turbocharger) and as a turbocharger with variable turbine geometry (VTG turbocharger). With said Miller control times and reduced valve lift of the intake valves, the different load points of internal combustion engine 100 can be operated up to a fired overrun mode of internal combustion engine 100 without wastegate deactivation. The exhaust gas aftertreatment device 10 makes it possible to achieve an operating characteristic of the internal combustion engine 100 in which a minimal load and residual gas tolerance as in operation with an open wastegate of a conventional turbocharger or a conventional exhaust gas tract can be expected, since there is only little or no damming effect on the respective turbines 66, 66A is to be expected. It is also conceivable in partial-load operation of internal combustion engine 100 to apply exhaust gas exclusively to the corresponding first catalytic converter 30, 30A close to the engine, bypassing the respective turbine 66, 66A, since in partial-load operation there are no impermissibly high exhaust gas temperatures which could damage the respective catalytic converters 30, 30A could lead are to be expected. In this respect, no disadvantages compared to a classic wastegate concept are to be expected.

Overall, the arrangement provided by the exhaust gas after-treatment device 10 can be used to quickly start up, ie to quickly reach the respective light-off temperature of the respective catalytic converters 30, 30A, as well as a high λ1 output of the internal combustion engine 100.

Reference List

10

exhaust aftertreatment device

12

first exhaust gas discharge channel

14

second exhaust gas discharge channel

16

exhaust flow

18

second exhaust stream

30

first catalyst

32

first exhaust duct

40

second catalyst

42

second exhaust duct

50

flow adjustment device

60

exhaust gas turbocharger

62

first flood

64

second flood

66

turbine wheel

68

compressor wheel

72

third exhaust duct

74

fourth exhaust duct

80

particle filter

82

underbody catalyst

84

underbody catalyst

86

rear silencer

100

internal combustion engine

102

cylinder

104

second cylinder

106

intercooler

108

collector

110

throttle

112

intake duct

114

intake silencer

116

intake air

118

exhaust duct

120

channel branching

K

motor vehicle

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102010032363 A1 [0003]

Claims (10)

Exhaust gas aftertreatment device (10) for an internal combustion engine (100), having at least one first exhaust gas discharge channel (12) through which an exhaust gas flow (16) can be discharged from at least one cylinder (102) of the internal combustion engine (100), and having at least one first catalytic converter (30 ) which, via a first exhaust gas duct (32) of the exhaust gas aftertreatment device (10), on the one hand is at least indirectly coupled to the first exhaust gas discharge duct (12) and on the other hand is at least indirectly coupled to at least one second catalytic converter (40) of the exhaust gas aftertreatment device (10), thereby characterized in that the exhaust gas aftertreatment device (10) has a second exhaust gas duct (42) which is at least indirectly coupled to the first exhaust gas discharge duct (12) and via which at least part of the exhaust gas flow (16) is fed to the at least one second catalytic converter (40), bypassing the at least one first Catalyst (30) can be fed, s and at least one flow adjustment device (50) which is connected at least indirectly to the first exhaust gas discharge channel (12), the first exhaust gas channel (32) and to the second exhaust gas channel (42) and which is at least between two states in which the first catalytic converter ( 30) different exhaust gas flow portions of the exhaust gas flow (16) exiting from the first exhaust gas discharge duct (12) can be supplied via the flow rate adjustment device (50). Exhaust aftertreatment device (10) after claim 1 , characterized in that the first catalytic converter (30) is designed for exhaust gas after-treatment of a smaller maximum exhaust gas mass flow than the second catalytic converter (40). Exhaust aftertreatment device (10) after claim 1 or 2 , characterized in that the first exhaust gas channel (32) upstream of the second catalytic converter (40) is coupled to the second exhaust gas channel (42). Exhaust gas aftertreatment device (10) according to one of the preceding claims, characterized in that the first catalytic converter (30) and the second catalytic converter (40) are of identical design. Exhaust gas aftertreatment device (10) according to one of the preceding claims, characterized in that the exhaust gas aftertreatment device (10) comprises at least one exhaust gas turbocharger (60) which, via the second exhaust gas duct (42), is connected on the one hand to the flow adjustment device (50) and on the other hand to the second catalytic converter (40 ) is coupled exhaust conducting. Exhaust aftertreatment device (10) after claim 5 , characterized in that the at least one exhaust gas turbocharger (60) is designed as a multiflow exhaust gas turbocharger. Exhaust aftertreatment device (10) after claim 6 , characterized in that a first flow (62) of the multi-flow exhaust gas turbocharger (60) with the second exhaust gas duct (42) and a second flow (64) of the multi-flow exhaust gas turbocharger (60) with a third exhaust gas duct (72) of the exhaust gas aftertreatment device (10), via which a second exhaust gas flow (18) can be discharged from at least one second cylinder (104) of the internal combustion engine (100), is coupled in an exhaust-gas-conducting manner, the third exhaust-gas channel (72) being at least indirectly connected to the flow rate adjustment device (50) on the one hand and at least indirectly to the on the other hand second catalyst (40) is coupled. Internal combustion engine (100) with an exhaust gas aftertreatment device (10) according to one of the preceding claims. Motor vehicle (K) with an internal combustion engine (100). claim 8 . Method for operating an exhaust gas treatment device (10) according to one of Claims 1 until 7 , In particular an internal combustion engine (100). claim 8 , in which the exhaust gas stream (16) is discharged from the at least one cylinder (102) via the at least one first exhaust gas discharge channel (12) during operation of the internal combustion engine (100) and is fed to the at least one flow rate adjustment device (50) and in which different states of the at least one flow adjustment device (50) depending on different operating states of the internal combustion engine (100), the at least one first catalytic converter (30) and/or the at least one second catalytic converter (40) and thereby the at least one first catalytic converter (30) via the at least a flow adjustment device (50) are supplied with exhaust gas flow components that differ from one another and are dependent on the states.

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