Internal combustion engine for a motor vehicle, method for operating such an internal combustion engine and motor vehicle

Abstract

Internal combustion engine (10) with an intake manifold (18) by means of which combustion air can be introduced into combustion chambers (16), with an exhaust manifold (20), with an exhaust gas turbocharger (22), with a secondary air system (38), with a secondary air line (40) by means of which at least a portion of the combustion air can be diverted from the intake manifold (18) at a first branch point (A1) arranged downstream of the compressor (26) and introduced as secondary air into the exhaust manifold (20), and has a first valve (42) arranged in the secondary air line (40), and with a recirculating air system (44) which has a first recirculating air line (46), and has a second valve (48) arranged in the first recirculating air line (46) by means of which the quantity of combustion air flowing through the first recirculating air line (46) can be adjusted, comprising: - a second recirculating air line (52) is provided, by means of which at least a part of the combustion air flowing through the secondary air line (40) can be diverted from the secondary air line (40) at a third branch point (A3) arranged upstream of the first valve (42) and downstream of the first branch point (A1) and introduced into the intake tract (18) at a second inlet point (E3) arranged upstream of the compressor (26), - a third valve (50) is provided, which is arranged in the secondary air line (40) upstream of the first valve (42) and upstream of the third branch point (A3), so that the quantity of combustion air flowing through the secondary air line (40) can be adjusted by means of the third valve (50); or is arranged in the second recirculating air line (52), so that the quantity of combustion air flowing through the second recirculating air line (52) can be adjusted by means of the third valve (50); and the second valve (48) and the third valve (50) are to be opened at least temporarily simultaneously in order to avoid pumping of the compressor (26).

Description

[0001] The invention relates to an internal combustion engine for a motor vehicle, in particular for a motor vehicle, according to the preamble of patent claim 1. Furthermore, the invention relates to a method for operating an internal combustion engine of a motor vehicle, in particular a motor vehicle, according to the preamble of patent claim 8. The invention also relates to a motor vehicle, in particular a motor vehicle, with such an internal combustion engine.

[0002] DE 10 2022 001 621 A1 discloses an internal combustion engine for a motor vehicle, comprising an intake tract through which combustion air can flow, by means of which the combustion air can be introduced into the combustion chambers of the internal combustion engine. An exhaust gas turbocharger is also provided, which has a turbine driven by the exhaust gas and a compressor driven by the turbine, by means of which the combustion air can be compressed.

[0003] DE 10 2012 101 767 A1 and DE 10 2021 100 458 A1, each considered individually, disclose an internal combustion engine for a motor vehicle, comprising an intake tract through which combustion air can flow, by means of which the combustion air can be introduced into the combustion chambers of the internal combustion engine, and an exhaust tract through which exhaust gas from the combustion chambers can flow, comprising an exhaust gas turbocharger having a turbine driven by the exhaust gas and a compressor driven by the turbine and designed to compress the combustion air. The internal combustion engine has a bypass air system with a bypass air line, by means of which at least a portion of the combustion air can be branched off from the intake tract at a branch point arranged downstream of the compressor and introduced into the intake tract at an inlet point arranged upstream of the compressor.A valve is arranged in the recirculation air line by means of which the amount of combustion air flowing through the recirculation air line can be adjusted.

[0004] The object of the present invention is to provide an internal combustion engine, a method for operating such an internal combustion engine and a motor vehicle with such an internal combustion engine, so that pumping of a compressor of an exhaust gas turbocharger of the internal combustion engine, also referred to as compressor pumping or pumping operation, can be particularly advantageously avoided.

[0005] This object is achieved by an internal combustion engine having the features of patent claim 1, by a method having the features of patent claim 8, and by a motor vehicle having the features of patent claim 10. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0006] A first aspect of the invention relates to an internal combustion engine, also referred to as an internal combustion engine or combustion motor and designed, for example, as a reciprocating piston engine, i.e., as a reciprocating piston machine, for a motor vehicle, also simply referred to as a vehicle, in particular for a motor car and very particularly for a passenger car. This means that the motor vehicle, preferably designed as a motor car, in particular as a passenger car, in its fully manufactured state has the internal combustion engine and can be driven by means of the internal combustion engine. The internal combustion engine has an intake tract, also referred to as an inlet tract, through which air can flow. By means of the intake tract, the air flowing through the intake tract can be introduced into combustion chambers of the internal combustion engine.During the firing operation of an internal combustion engine, combustion processes occur in the respective combustion chamber. During each combustion process, a fuel-air mixture, also referred to simply as a mixture, is burned. The fuel-air mixture comprises a preferably liquid fuel and air, so the air flowing through the intake tract is also referred to as combustion air.

[0007] The combustion of the mixture produces exhaust gas from the internal combustion engine. The internal combustion engine has an exhaust tract through which the exhaust gas from the combustion chambers can flow. The internal combustion engine also has at least one or exactly one exhaust gas turbocharger, which has a turbine arranged in the exhaust tract and driven by the exhaust gas. Furthermore, the exhaust gas turbocharger has a compressor arranged in the exhaust tract, which is driven by the turbine. By driving the compressor, the combustion air flowing through the intake tract can be compressed. The air compressed by the compressor (combustion air) is also referred to as charge air.

[0008] The internal combustion engine also has a secondary air system, also referred to as a secondary air device, which has at least one secondary air line, also referred to as the first secondary air line. When reference is made above and below to the secondary air line, this refers to the first secondary air line, unless otherwise stated. By means of the secondary air line, at least a portion of the combustion air can be branched off from the intake tract at a first branch point and introduced, in particular directly, into the exhaust tract as secondary air. The first branch point is arranged in the intake tract downstream of the compressor.This means that, in the flow direction of the combustion air flowing through the intake tract, the first branching point is arranged downstream of the compressor and in particular upstream of all of the combustion chambers of the internal combustion engine, so that the combustion air that can be branched off from the intake tract at the first branching point is air compressed by the compressor, and therefore combustion air compressed by the compressor. Thus, for example, the compressor can function as a secondary air pump, by means of which the secondary air can be conveyed into the secondary air line, through the secondary air line and into the exhaust tract. In particular, the secondary air can be introduced by means of the secondary air line, bypassing all of the combustion chambers of the internal combustion engine, and thus directly into the exhaust tract.This means that the secondary air, on its way from the first branch point through the secondary air line and into the exhaust tract, bypasses the combustion chambers of the internal combustion engine, in particular all of them, and thus does not flow through the combustion chambers of the internal combustion engine, in particular through any combustion chamber. In the exhaust tract, the secondary air line can be used, for example, to effectively and efficiently heat and / or maintain the temperature of at least one exhaust gas aftertreatment component arranged in the exhaust tract for aftertreating the exhaust gas.

[0009] The secondary air system also has a first valve arranged in the secondary air line, which is also referred to as a secondary air valve or first secondary air valve. When reference is made above and below to the secondary air valve, this means the first secondary air valve, i.e. the first valve, unless otherwise stated. By means of the first valve, a quantity of secondary air flowing through the secondary air line (first secondary air line) can be adjusted, i.e. varied. For example, the first valve can be adjusted between at least two states, namely a first state and a second state. The first state is, for example, a first closed state of the first valve, wherein in the first closed state of the first valve, the secondary air line is fluidically blocked by means of the first valve.The second state of the first valve is, for example, a first open state of the first valve, wherein the first valve in the first open state releases the secondary air line, thus preventing fluidic blocking of the secondary air line caused by the first valve.

[0010] The internal combustion engine also has a recirculation system, also referred to as a bypass air device, which is provided in particular in addition to the secondary air system and has a recirculation line provided in particular in addition to the secondary air line. By means of the recirculation line, at least a portion of the combustion air, compressed in particular by means of the compressor, can be branched off from the intake tract at a second branch point and introduced into the intake tract at an inlet point arranged upstream of the compressor, which is also referred to as the first inlet point. When reference is made above and below to the inlet point, this means the first inlet point, unless otherwise stated. The second branch point is arranged downstream of the compressor.In other words, in the flow direction of the combustion air flowing through the intake tract, the second branch point is located downstream of the compressor.

[0011] The overrun air system also has a second valve arranged in the overrun air line, which is also referred to as the overrun air valve or first overrun air valve. When reference is made above and below to the overrun air valve, this means the first overrun air valve unless otherwise stated. By means of the second valve, a quantity of combustion air flowing through the overrun air line can be adjusted. For example, the second valve can be switched or adjusted between at least two states, namely a third state and a fourth state. The third state is, for example, a second closed state of the second valve, which in the second closed state fluidically blocks the overrun air line. In other words, in the second closed state of the second valve, the overrun air line is fluidically blocked, i.e. closed, by means of the second valve.The fourth state is, for example, a second open state of the second valve, which, in the second open state, releases the overrun air line. This means that, in the fourth state of the second valve, the fluidic blocking of the overrun air line caused by the second valve is prevented.

[0012] In order to be able to avoid compressor pumping, also referred to as pumping operation or compressor surging, in a particularly advantageous manner, in particular particularly safely, and in a space-saving and cost-effective manner, the internal combustion engine according to the invention has a second recirculation air line, which is provided in particular in addition to the first recirculation air line and in addition to the secondary air line and which can, for example, be a component of the recirculation air system. By means of the second recirculation air line, at least a portion of the combustion air flowing through the secondary air line can be branched off from the secondary air line at a third branch point and introduced into the intake tract at a second inlet point.

[0013] The third branch point is located upstream of the first valve and downstream of the first branch point in the direction of flow of the combustion air flowing through the secondary air line. In principle, it would be conceivable for the first inlet point and the second inlet point to coincide, or for the first and second inlet points to be spaced apart from each other.

[0014] Also provided is a third valve, in particular in addition to the first valve and in addition to the second valve, which third valve is arranged upstream of the first valve and upstream of the third branch point and in particular downstream of the first branch point in the flow direction of the combustion or secondary air flowing through the secondary air line. By means of the third valve, a quantity of combustion air flowing through the secondary air line can be adjusted. For example, the third valve can be adjusted, i.e. switched, between at least two states, namely a fifth state and a sixth state. The sixth state of the third valve is, for example, a third open state of the third valve, which in the third open state fluidically opens the secondary air line, i.e. for a flow of combustion air through the secondary air line.In other words, it is provided that in the third open state of the third valve, a fluidic blocking of the secondary air line caused by the third valve is prevented. The sixth state of the third valve is, for example, a third closed state of the third valve, by means of which the secondary air line is fluidic blocked in the third closed state of the third valve. Thus, the respective valve is closed in its respective closed state, and the respective valve is open in its respective open state.

[0015] Furthermore, the invention provides that the second valve and the third valve are to be opened at least temporarily simultaneously, in particular are open, in order to thereby prevent compressor surge. In other words, the invention uses the second valve and the third valve to prevent compressor surge by opening the first valve and the second valve and thereby being open at least temporarily and thus at least for a period of time simultaneously. As a result, combustion air can be branched off from the intake tract downstream of the compressor via the first recirculation air line as well as via the secondary air line and the second recirculation air line and guided, i.e. recirculated, into the intake tract upstream of the compressor, so that compressor surge can be prevented reliably, in a space-saving and cost-effective manner.In particular, the invention makes it possible to recirculate the combustion air, in particular compressed by means of the compressor, upstream of the compressor into the intake tract via the second valve and the third valve and thereby via the first recirculation air line, the secondary air line and the second recirculation air line at at least some operating points of the internal combustion engine in order to be able to reliably avoid compressor surges as far as possible.

[0016] A first length of the intake tract extending from the compressor to the combustion chambers is also referred to as a charging section or charge air section, since the first length runs downstream of the compressor and in particular upstream of the combustion chambers and can therefore be flowed through by the air compressed by the compressor, i.e. by the charge air. A second length of the intake tract running upstream of the compressor is also referred to as an air section, since the combustion air flowing through the air section is not compressed by the compressor and is therefore not charge air. If, for example, the second length runs upstream of the compressor and downstream of an air filter arranged in the intake tract for filtering the combustion air, the second length is also referred to as the clean air section.By simultaneously opening the second valve and the third valve, i.e. when the second valve and the third valve are open at the same time, a particularly large amount of charge air can be diverted from the charge air path and released into the air path in a short time via the second valve and the third valve, and thus via the first bypass air line, the second bypass air line and the secondary air line, so that an advantageous pressure reduction in the charge air path can be achieved in a short time. This can reliably prevent compressor surge. Compressor surge can damage a bearing of the exhaust gas turbocharger and cause strong acoustic abnormalities, which can now be advantageously avoided by the invention.

[0017] If the second valve is open, at least a portion of the combustion air flowing through the intake tract can be branched off from the intake tract at the second branch point and introduced into the first recirculation air line and subsequently flow through the first recirculation air line and guided and returned to the first inlet point by means of the first recirculation air line and introduced into the intake tract at the first inlet point.

[0018] By opening the third valve, i.e. when the third valve is open, at least a portion of the combustion air flowing through the intake tract can be branched off from the intake tract at the first branching point and introduced into the secondary air line and subsequently flow through at least a portion of the secondary air line, wherein, because the third branching point is arranged downstream of the third valve, the combustion air introduced into the secondary air line can flow through the secondary air line at least to such an extent that the combustion air introduced into the secondary air line can flow, in particular via the third valve, to the third branching point.As a result, at least a portion of the combustion air introduced into the secondary air line and thus flowing through the partial region of the secondary air line can be branched off from the secondary air line at the third branch point and introduced into the second recirculation air line and subsequently flow through the recirculation air line and guided, in particular recirculated, to the second inlet point by means of the recirculation air line and introduced into the intake tract at the second inlet point, so that combustion air compressed in particular by means of the compressor can be returned from downstream of the compressor, in particular from the charge air path, to upstream of the compressor, in particular to the air path, both via the first recirculation air line and the second valve and via the third valve, the second recirculation air line and at least the partial region of the secondary air line.As a result, compressor surge can be reliably avoided in a space-saving and cost-effective manner. Since, moreover, the first valve in the secondary air line is arranged downstream of the third valve and downstream of the third branching point, the amount of secondary air flowing through the secondary air line, for example from the third branching point, and / or the amount of secondary air that is introduced into the exhaust tract by means of the secondary air line can be adjusted, particularly when the second valve and the third valve are open at the same time, i.e. are open, so that the second valve and the third valve are in the second open state and the third open state simultaneously, in particular when the second valve and the third valve are open at the same time, i.e. are open.

[0019] It has proven particularly advantageous if the second valve and the third valve are opened at least temporarily simultaneously, and the first valve is closed at the same time, in order to prevent compressor surge. In other words, it is preferably provided that the first valve is closed while the second valve and the third valve are opened simultaneously, so that the first valve is in the first closed state, while the second valve is in the second open state, and the third valve is in the third open state.As a result, for example, the combustion air introduced into the secondary air line at the first branch point can only flow through the secondary air line as far as the closed, first valve, so that, for example, the aforementioned partial region extends from the first branch point to the third valve, wherein, for example, the third valve and the third branch point are arranged in the aforementioned partial region of the secondary air line. The combustion air introduced into the secondary air line cannot flow further than the first valve because the first valve is closed, so that the secondary air line is fluidically blocked, i.e., closed or sealed, from the first valve onwards as viewed towards the exhaust tract.Thus, the combustion air can be recirculated from the charging section to the air section via both the first bypass air line and the secondary air line, in particular the aforementioned section of the secondary air line, while the introduction of secondary air via the secondary air line, also known as blowing in, is prevented because the first valve is closed, i.e., in its first closed state. This allows compressor surge to be particularly reliably prevented.

[0020] In order to be able to avoid compressor surges particularly reliably, a further embodiment of the invention provides that the second inlet point is arranged upstream of the first inlet point in the flow direction of the combustion air flowing through the intake tract and is in particular spaced apart from the first inlet point.

[0021] A further embodiment is characterized in that the first branching point is arranged downstream of the second branching point in the flow direction of the combustion air flowing through the intake tract and, in particular, is spaced apart from the second branching point. This allows the combustion air to be recirculated particularly advantageously from the charge air path to the air path, so that compressor surge can be reliably avoided.

[0022] Furthermore, to avoid compressor surge, it has proven particularly advantageous if the internal combustion engine has an electric motor by means of which the compressor can be driven electrically, i.e., using electrical energy with which the electric motor can be or is supplied. Thus, the exhaust gas turbocharger is preferably designed as an electrically assisted exhaust gas turbocharger.

[0023] In a further, particularly advantageous embodiment of the invention, it is provided that the first valve and / or the third valve is designed to fluidically block the secondary air line by closing the first valve and / or the third valve. In other words, if the first or third valve is closed, so that the first or third valve is in the closed state, the secondary air line is fluidically blocked. This allows compressor surge to be particularly reliably prevented, since combustion air can be particularly advantageously recirculated from the charge air line to the air line.

[0024] In order to switch the valves as needed and thus, for example, to selectively open or close them, a further embodiment of the invention provides for the first valve and / or the second valve and / or the third valve to be electrically operable to thereby adjust the respective flow rate. In particular, for example, the respective valve is electrically controllable to selectively switch the respective valve between the respective open state and the respective closed state. This allows the valves to be switched as needed, thereby reliably preventing compressor surge.

[0025] A second aspect of the invention relates to a method for operating an internal combustion engine, in particular according to the first aspect of the invention, of a motor vehicle. In the method, the internal combustion engine has an intake tract through which combustion air can flow, by means of which the combustion air can be introduced into combustion chambers of the internal combustion engine. In the method, the internal combustion engine has an exhaust tract through which exhaust gas from the combustion chambers can flow, and an exhaust gas turbocharger, which has a turbine driven by the exhaust gas and a compressor driven by the turbine, by means of which the combustion air can be compressed.In the method, the internal combustion engine also has a secondary air system having a secondary air line, by means of which at least a portion of the combustion air can be branched off from the intake tract at a first branching point arranged downstream of the compressor and introduced into the exhaust tract as secondary air. In the second aspect of the invention, the secondary air system also has a first valve arranged in the secondary air line, by means of which a quantity of secondary air flowing through the secondary air line can be adjusted. In the method, the internal combustion engine also has a recirculation air system, which has a recirculation air line, also referred to as a first recirculation air line.By means of the recirculating air line (first recirculating air line), at least a portion of the combustion air, in particular compressed by the compressor, can be branched off from the intake tract at a second branching point located downstream of the compressor and introduced into the intake tract at an inlet point located upstream of the compressor, also referred to as the first inlet point. In this method, the recirculating air system also has a second valve arranged in the recirculating air line, by means of which the amount of combustion air flowing through the recirculating air line (first recirculating air line) can be adjusted.

[0026] In order to be able to particularly advantageously avoid compressor pumping, also referred to as compressor pumping or pumping operation, it is provided in the second aspect of the invention that the internal combustion engine, in particular the secondary air system, has a second recirculation air line, by means of which at least part of the combustion air flowing through the secondary air line can be branched off from the secondary air line at a third branch point arranged upstream of the first valve and downstream of the first branch point and can be introduced into the intake tract at a second inlet point arranged upstream of the compressor.

[0027] In addition, the internal combustion engine, in particular the secondary air system, has a third valve which is arranged in the secondary air line upstream of the first valve and upstream of the third branch point, so that a quantity of combustion air flowing through the secondary air line can be adjusted by means of the third valve.

[0028] In the method, the internal combustion engine is operated at least temporarily in an operating state in which the second valve and the third valve are open simultaneously, thereby preventing compressor surge. Advantages and advantageous embodiments of the first aspect of the invention are to be regarded as advantages and advantageous embodiments of the second aspect of the invention, and vice versa.

[0029] In order to be able to reliably prevent compressor surges, it is provided in an embodiment of the second aspect of the invention that in the operating mode the first valve is closed and thereby the secondary air line is fluidically blocked, while the second valve and the third valve are opened simultaneously.

[0030] A third aspect of the invention relates to a motor vehicle, also simply referred to as a vehicle and preferably designed as a motor vehicle, in particular as a passenger car, which has an internal combustion engine according to the second aspect of the invention and is drivable by means of the internal combustion engine. Advantages and advantageous embodiments of the first aspect and the second aspect of the invention are to be regarded as advantages and advantageous embodiments of the third aspect of the invention, and vice versa.

[0031] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawings. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the single figure, can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the invention.

[0032] The drawing shows in the only figure a schematic representation of an internal combustion engine for a motor vehicle, with a secondary air system and a recirculation air system.

[0033] The single figure shows a schematic representation of an internal combustion engine 10, also referred to as an internal combustion engine or combustion motor and in this case designed as a reciprocating piston engine, thus as a reciprocating piston machine, for a motor vehicle, also simply referred to as a vehicle. This means that the motor vehicle, preferably designed as a motor vehicle, in particular as a passenger car, has the internal combustion engine 10 and can be driven by the internal combustion engine 10. The internal combustion engine 10 has an engine block 12, which in the embodiment shown in the figure is designed as a cylinder housing, in particular as a cylinder crankcase. The engine block 12 and thus the internal combustion engine 10 have, in this case, in particular exactly four cylinders 14, wherein a respective combustion chamber 16 of the internal combustion engine 10 is partially delimited by the respective cylinder 14.Thus, in the embodiment shown in the figure, the internal combustion engine 10 has, in particular, precisely four combustion chambers 16. During fired operation of the internal combustion engine 10, combustion processes take place in the respective combustion chamber 16, in particular such that within a respective operating cycle of the internal combustion engine 10, one of the combustion processes takes place in the respective combustion chamber 16, in particular precisely. The internal combustion engine 10 is designed as a 4-stroke engine. During each combustion process, a respective mixture, also referred to as a fuel-air mixture, is combusted, resulting in exhaust gas from the internal combustion engine 10.

[0034] The internal combustion engine 10 has an intake tract 18 through which air can flow. At least a portion of the air flowing through the intake tract 18 can be directed to and into the combustion chambers 16 by means of the intake tract 18, with the aforementioned mixture comprising the air introduced into the respective combustion chamber 16. Therefore, the air flowing through the intake tract 18 is also referred to as combustion air or fresh air.

[0035] The internal combustion engine 10 also has an exhaust tract 20 through which the exhaust gas from the combustion chambers 16 can flow. The internal combustion engine 10 also has at least one or precisely one exhaust gas turbocharger 22, which has a turbine 24 arranged in the exhaust tract 20 and driven by the exhaust gas. Furthermore, the exhaust gas turbocharger 22 has a compressor 26 arranged in the intake tract 18, which compressor is driven by the turbine 24. By driving the compressor 26, the combustion air flowing through the intake tract 18 can be compressed by the compressor 26. The compressed combustion air is also referred to as charge air.

[0036] The figure shows a first longitudinal region L1 and a second longitudinal region L2 of the intake tract 18. The first longitudinal region L1 runs upstream of the compressor 26 in the flow direction of the combustion air flowing through the intake tract 18, for example such that the longitudinal region L1 runs between the compressor 26 and an air filter (not shown in the figure) arranged in the intake tract 18 for filtering the combustion air. Therefore, the longitudinal region L1 is also referred to as an air path, in particular as a clean air path. The second longitudinal region L2 of the intake tract 18 runs downstream of the compressor 26 and in particular between the compressor 26 and the combustion chambers 16, i.e. upstream of the combustion chambers 16 and downstream of the compressor 26. The charge air can therefore flow through the longitudinal region L2, so that the longitudinal region L2 is also referred to as a charging path or charge air path.

[0037] For example, the turbine 24 has a turbine wheel driven by the exhaust gas. The compressor 26 has, for example, a compressor wheel driven by the turbine wheel, by means of which the combustion air can be compressed by driving the compressor wheel. The exhaust gas turbocharger 22 has, for example, a shaft via which the compressor wheel can be driven by the turbine wheel. The shaft, the compressor wheel, and the turbine wheel are components of a rotor assembly of the exhaust gas turbocharger 22, the rotor assembly of which is rotatably mounted on a bearing housing 28 of the exhaust gas turbocharger 22. In the exemplary embodiment shown in the figure, the internal combustion engine 10 has an electric motor 30, by means of which the compressor wheel and thus the compressor 26 can be driven, for example via the shaft. Furthermore, it is conceivable that the turbine wheel and thus the turbine 24 can be driven by means of the electric motor 30, in particular via the shaft.

[0038] The turbine 24 is assigned a bypass device 32, which has a bypass line 34 and a bypass valve 36. The bypass valve 36 is arranged in the bypass line 34. The bypass valve 36 is also referred to as a waste gate or waste gate valve. The bypass line 34 is fluidly connected to the exhaust tract 20 at a first connection point V1 and at a second connection point V2, such that by means of the bypass line 34 at least a portion of the exhaust gas flowing through the exhaust tract 20 can be branched off from the exhaust tract 20 at the connection point V1, guided to the second connection point V2, and introduced into the exhaust tract 20 at the connection point V2. The connection point V1 is arranged upstream of the turbine 24 in the flow direction of the exhaust gas flowing through the exhaust tract 20, wherein the connection point V2 is arranged downstream of the turbine 24.The turbine 24 can thus be bypassed via the bypass line 34, at least by the aforementioned portion of the exhaust gas. This means that the exhaust gas flowing through the bypass line 34 bypasses the turbine 24, and therefore does not flow through the turbine 24 and thus does not drive the turbine 24. The bypass valve 36 can be used to adjust the amount of exhaust gas flowing through the bypass line 34. By adjusting the amount of exhaust gas flowing through the bypass line 34, the power of the turbine 24 can be adjusted, i.e. varied, as a result of which, for example, a boost pressure of the charge air can be adjusted. In this case, the combustion air is compressed and thus brought from a first pressure to a boost pressure that is higher than the first pressure by compressing the combustion air.

[0039] The internal combustion engine 10 also has a secondary air system 38, which has a secondary air line 40. By means of the secondary air line 40, at least a portion of the combustion air flowing through the intake tract 18 can be branched off from the intake tract 18 at a first branching point A1 arranged downstream of the compressor 26 and in particular upstream of the combustion chambers 16 and introduced as secondary air into the exhaust tract, such that the secondary air can be introduced into the exhaust tract 20 at a first inlet point E1. For this purpose, the secondary air line 40 is fluidly connected to the intake tract 18 at the branching point A1 and to the exhaust tract 20 at the inlet point E1. It can be seen that the branching point A1 is arranged downstream of the compressor 26 and upstream of the combustion chambers 16. The inlet point E1 is located downstream of the combustion chambers 16 and upstream of the turbine 24, in particular upstream of the connection point V1. From Fig.It can be seen that, by means of the secondary air line 40, the secondary air flowing through the secondary air line 40 can be introduced, bypassing the, in particular all, combustion chambers 16 of the internal combustion engine 10 and thus directly into the exhaust tract 20 at the inlet point E1. This means that the secondary air, on its way from the branch point A1 through the secondary air line 40 to the branch point E1 and into the exhaust tract 20, flows through the, in particular all, combustion chambers 16 of the internal combustion engine 10, i.e., does not flow through the combustion chambers 16 and, in the present case, does not flow through any of the combustion chambers of the internal combustion engine 10.

[0040] The secondary air system 38 has a first valve 42, which is arranged in the secondary air line 40. For example, the valve 42 is arranged upstream of the inlet point E1 or at the inlet point E1. By means of the valve 42, also referred to as a secondary air valve, for example, the amount of secondary air flowing through the secondary air line 40 can be adjusted. In particular, the valve 42 can be switched or adjusted between a first open state and a first closed state. In the first closed state, the valve 42 is closed, whereby the valve 42 fluidically blocks the secondary air line 40. In the first open state, the valve 42 is open, i.e., open, whereby the valve 42 permits a flow of combustion air through the secondary air line 40.In other words, in the first open state of the first valve 42, a fluidic blocking of the secondary air line 40 caused by the first valve 42 is avoided. By means of the first valve 42, a quantity of secondary air flowing through the secondary air line can be adjusted.

[0041] The internal combustion engine 10 also has a bypass air system 44, which has a first bypass air line 46. By means of the first bypass air line 46, at least a portion of the combustion air compressed, in particular, by means of the compressor 26, i.e., at least a portion of the charge air, can be branched off from the intake tract 18 at a second branch point A2 arranged downstream of the compressor 26 and upstream of the combustion chambers 16, in particular upstream of the first branch point A1, and can be introduced into the intake tract 18 at a second inlet point E2 arranged upstream of the compressor 26. It can be seen that the branch points A1 and A2 are arranged in the charge air path, so that the combustion air that can be branched off at the branch point A1, A2 is the charge air, i.e., at least a portion of the charge air. The inlet point E2 is located in the clean air line and thus upstream of the compressor 26 and downstream of the air filter.

[0042] The overrun air system 44 also has a second valve 48, which is arranged in the first overrun air line 46. By means of the second valve 48, the amount of combustion air flowing through the first overrun air line 46 can be adjusted. For example, the second valve 48 can be adjusted or switched between a second open state and a second closed state. In the second closed state of the second valve 48, the second valve 48 is closed, as a result of which the second valve 48 fluidically blocks the first overrun air line 46. In the second open state, the second valve 48 is opened or open, so that the second valve 48 fluidically releases the first overrun air line 46, thus preventing the fluidic blocking of the overrun air line 46 caused by the second valve 48.

[0043] In order to particularly advantageously prevent pumping of the compressor 26, also referred to as pumping operation or compressor surging, the internal combustion engine 10, in particular the secondary air system 38, has a third valve 50, which is arranged in the secondary air line 40 upstream of the first valve 42. For example, the valve 50 is arranged at the branch point A1 or downstream of the branch point A1. By means of the third valve 50, a quantity of combustion air flowing through the secondary air line 40 can be adjusted. For example, the third valve 50 can be adjusted or switched between a third open state and a third closed state. In the third closed state of the third valve 50, the third valve 50 is closed, whereby the third valve 50 fluidically blocks the secondary air line 40.In the third open state of the third valve 50, the third valve 50 is opened or open, whereby the third valve 50 releases the secondary air line 40, in particular for a flow of combustion air through the secondary air line 40. In other words, in the third open state of the third valve 50, a fluidic blockage of the secondary air line 40 caused by the third valve 50 is eliminated.

[0044] It can be seen that the secondary air line 40 can be divided or split into three sub-regions T1, T2, and T3. In other words, the secondary air line 40 has the three sub-regions T1, T2, and T3. It can be seen that the first sub-region T1 extends from the branching point A1 to the valve 50, so that the sub-region T1 runs upstream of the valve 50 and, for example, downstream of the branching point A1. The second sub-region T2 extends from the valve 50 to the valve 42, so that, for example, the second sub-region T2 runs between the valves 42 and 50, thus downstream of the valve 50 and upstream of the valve 42. The third sub-region T3 runs downstream of the valve 42 and upstream of the inlet point E1, thus for example between the valve 42 and the inlet point E1, so that the sub-region T3 extends from the valve 42 to the inlet point E1.

[0045] Since, for example, the partial region T1 runs upstream of the valve 50, at least a portion of the combustion air flowing through the intake tract 18 can flow into the partial region T1 at the branch point A1 and flow at least as far as the valve 50, both in the third open state and in the third closed state of the valve 50.

[0046] The internal combustion engine 10, in particular the overrun air recirculation system 44, also has a second overrun air recirculation line 52, by means of which at least a portion of the combustion air flowing through the secondary air line 40 can be branched off from the secondary air line 40 at a third branching point A3 arranged upstream of the first valve 42 and downstream of the third valve 50, and can be introduced into the intake tract 18 at a third inlet point E3 arranged upstream of the compressor 26. It can be seen that the valve 50 is arranged upstream of the valve 42 and upstream of the branching point A3 in the secondary air line 40. The inlet point E3 is arranged in the clean air section and thus upstream of the compressor 26 and downstream of the air filter. In the present case, the third inlet point E3 is arranged upstream of the second inlet point E2.

[0047] A method for operating the internal combustion engine 10 is explained below. The method provides that the internal combustion engine 10 is operated at least temporarily in an operating state in which the second valve 48 and the third valve 50 are open simultaneously, in order to thereby prevent compressor surge. Preferably, the first valve 42 is closed in this operating mode, as a result of which the secondary air line 40 is fluidically blocked. Thus, charge air can be branched off from the charge air path via the branch point A2, the overrun air line 46 and the valve 48, as well as via the branch point A1, the partial area T1, the valve 50 and the branch point A3, as well as a part of the partial area T2 and the overrun air line 52, and can be returned to the clean air path and released into the clean air path, in order to thereby prevent compressor surge in a particularly advantageous and safe manner.If the valve 50 is open while the valve 42 is closed, at least a portion of the charge air flowing through the charge air path can flow into the secondary air line 40 at the branch point A1 and thereby into the sub-area T1, flow through the sub-area T1 and also flow through the valve 50 and in particular flow to the branch point A3 and flow into the second recirculation air line 52 at the branch point A3 and subsequently be recirculated by means of the second recirculation air line 52 to the inlet point E3 and thus into the clean air path.Since the valve 42 is preferably closed, combustion air flowing beyond the branch point A3 can flow to the valve 42 and, for example, flow through the partial area T2, but the combustion air flowing through the partial area T2 and flowing to the valve 42 cannot flow through the partial area T3 and thus cannot be introduced into the exhaust gas tract 20 because the valve 42 is closed.

[0048] It would be conceivable for valves 50 and 48 to be open simultaneously in this operating mode or in a second operating mode, while valve 42 is open simultaneously. This allows secondary air to be introduced, i.e. blown in, into the exhaust tract 20, and combustion air from and to the charge air section can be particularly advantageously recirculated into the clean air section in order to reliably prevent compressor surge. Overall, it can be seen that, at least in the aforementioned operating mode, both valve 48 and valve 50 are used as bypass valves, although valve 48 is arranged in the bypass line 46 and valve 50 in the secondary air line 40. Valve 50 can be used as a secondary air valve.

[0049] Furthermore, it can be seen from the figure that a throttle valve 54 is arranged in the intake tract 18, by means of which a quantity of combustion air to be supplied to the respective combustion chamber 16 can be adjusted. List of reference symbols 10 Internal combustion engine 12 Engine block 14 cylinders 16 combustion chamber 18 Intake tract 20 Exhaust system 22 exhaust gas turbochargers 24 turbines 26 compressors 28 bearing housings 30 electric motor 32 Bypass facility 34 Bypass line 36 Bypass valve 38 Secondary air system 40 Secondary air line 42 first valve 44 recirculation system 46 first recirculation air line 48 second valve 50 third valve 52 second recirculation air line 54 Throttle valve A1 - A3 junctions E1 - E3 discharge points L1, L2 length ranges T1 - T3 sub-areas V1 first connection point V2 second connection point

Claims

[1] Internal combustion engine (10) for a motor vehicle, comprising an intake tract (18) through which combustion air can flow, by means of which the combustion air can be introduced into combustion chambers (16) of the internal combustion engine (10), comprising an exhaust tract (20) through which exhaust gas from the combustion chambers (16) can flow, comprising an exhaust gas turbocharger (22) having a turbine (24) driven by the exhaust gas and a compressor (26) driven by the turbine (24) and designed to compress the combustion air, comprising a secondary air system (38) which has a secondary air line (40), by means of which at least a portion of the combustion air can be branched off from the intake tract (18) at a first branching point (A1) arranged downstream of the compressor (26) and introduced as secondary air into the exhaust tract (20), and comprising a first valve (42) arranged in the secondary air line (40),by means of which a quantity of secondary air flowing through the secondary air line (40) can be adjusted, and with a recirculation air system (44) which has a first recirculation air line (46), by means of which at least a portion of the combustion air can be branched off from the intake tract (18) at a second branching point (A2) arranged downstream of the compressor (26) and introduced into the intake tract (18) at an inlet point (E2) arranged upstream of the compressor (26), and a second valve (48) arranged in the first recirculation air line (46), by means of which a quantity of combustion air flowing through the first recirculation air line (46) can be adjusted, , characterized by , that: - a second recirculation air line (52) is provided, by means of which at least a portion of the combustion air flowing through the secondary air line (40) can be branched off from the secondary air line (40) at a third branch point (A3) arranged upstream of the first valve (42) and downstream of the first branch point (A1) and can be introduced into the intake tract (18) at a second inlet point (E3) arranged upstream of the compressor (26), - a third valve (50) is provided, which is arranged in the secondary air line (40) upstream of the first valve (42) and upstream of the third branch point (A3), so that a quantity of combustion air flowing through the secondary air line (40) can be adjusted by means of the third valve (50); and - the second valve (48) and the third valve (50) are to be opened at least temporarily simultaneously in order to avoid pumping of the compressor (26). [2] Internal combustion engine (10) according to claim 1, characterized by that the second valve (48) and the third valve (50) are to be opened at least temporarily simultaneously and the first valve (42) is to be closed at the same time in order to thereby prevent pumping of the compressor (26). [3] Internal combustion engine (10) according to claim 1 or 2, characterized by that the second inlet point (E3) is arranged upstream of the first inlet point (E2). [4] Internal combustion engine (10) according to one of the preceding claims, characterized by that the first branch point (A1) is arranged downstream of the second branch point (A2). [5] Internal combustion engine (10) according to one of the preceding claims, characterized by an electric motor (30) by means of which the compressor (26) can be driven electrically. [6] Internal combustion engine (10) according to one of the preceding claims, characterized bythat the first valve (42) and / or the third valve (50) is designed to fluidically block the secondary air line (40) by closing the first valve (42) and / or the third valve (50). [7] Internal combustion engine (10) according to one of the preceding claims, characterized by that the first valve (42) and / or the second valve (48) and / or the third valve (50) is electrically operable to thereby adjust the respective quantity. [8] Method for operating an internal combustion engine (10) of a motor vehicle, in which the internal combustion engine (10) comprises: - an intake tract (18) through which combustion air can flow, by means of which the combustion air can be introduced into combustion chambers (16) of the internal combustion engine (10); - an exhaust tract (20) through which exhaust gas from the combustion chambers (16) can flow; - an exhaust gas turbocharger (22) comprising: ◯ a turbine (24) driven by the exhaust gas; and ◯ a compressor (26) driven by the turbine (24) and designed to compress the combustion air; - a secondary air system (38) comprising: ◯ a secondary air line (40), by means of which at least part of the combustion air can be branched off from the intake tract (18) at a first branching point (A1) arranged downstream of the compressor (26) and introduced into the exhaust tract (20) as secondary air; and ◯ a first valve (42) arranged in the secondary air line (40), by means of which a quantity of secondary air flowing through the secondary air line (40) can be adjusted, and - a recirculation system (44) comprising: ◯ a first recirculation air line (46), by means of which at least part of the combustion air can be branched off from the intake tract (18) at a second branching point (A2) arranged downstream of the compressor (26) and introduced into the intake tract (18) at an inlet point (E2) arranged upstream of the compressor (26); and ◯ a second valve (48) arranged in the first recirculation air line (46), by means of which a quantity of combustion air flowing through the recirculation air line (46) can be adjusted, characterized by , that: - a second recirculation air line (52) is provided, by means of which at least a portion of the combustion air flowing through the secondary air line (40) can be branched off from the secondary air line (40) at a third branch point (A3) arranged upstream of the first valve (42) and downstream of the first branch point (A1) and can be introduced into the intake tract (18) at a second inlet point (E3) arranged upstream of the compressor (26), - a third valve (50) is provided, which is arranged in the secondary air line (40) upstream of the first valve (42) and upstream of the third branch point (A3), so that a quantity of combustion air flowing through the secondary air line (40) can be adjusted by means of the third valve (50); and - the internal combustion engine (10) is operated at least temporarily in an operating state in which the second valve (48) and the third valve (50) are opened simultaneously in order to thereby prevent pumping of the compressor (26). [9] Method according to claim 8, characterized by that in the operating mode the first valve (42) is closed and thereby the secondary air line (40) is fluidically blocked, while the second valve (48) and the third valve (50) are open. [10] Motor vehicle, with an internal combustion engine (10) according to one of claims 1 to 7, wherein the motor vehicle can be driven by means of the internal combustion engine (10).

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