COMBUSTION ENGINE FOR A MOTOR VEHICLE AS WELL AS MOTOR VEHICLE

Description

[0001] The invention relates to an internal combustion engine for a motor vehicle according to the preamble of claim 1. Furthermore, the invention relates to a motor vehicle.

[0002] DE 10 2017 213 004 A1 discloses an internal combustion engine comprising a combustion engine, a fresh gas stream for supplying fresh gas to the combustion engine, an exhaust stream for removing exhaust gas from the combustion engine, and at least one exhaust aftertreatment device integrated into the exhaust stream. The internal combustion engine further comprises an electrically driven compressor integrated into the fresh gas stream or the exhaust stream, and a heating device upstream of or integrated into the exhaust aftertreatment device for heating a gas flowing through it. The internal combustion engine has a control device designed such that, when the combustion engine is not in operation, it operates the compressor and the heating device simultaneously as needed if the temperature of a component of the internal combustion engine falls below a defined limit.

[0003] Furthermore, DE 10 2018 129 955 A1 discloses a method for preconditioning an exhaust system for the removal and cleaning of combustion exhaust gases from an internal combustion engine, in particular an internal combustion engine of a motor vehicle, wherein air is heated in the exhaust system by a heating element. A blower generates a hot air stream in the exhaust system with the heated air, wherein a first catalyst of the exhaust system is heated by the hot air stream to a minimum operating temperature.

[0004] Furthermore, DE 10 2013 001 080 A1 discloses a method for operating a drive device with an internal combustion engine and with an exhaust system connected to the internal combustion engine, which exhaust system has at least one catalytic converter. A warm air stream heated by a heating device is supplied to the catalytic converter for heating in at least one operating state of the internal combustion engine. The warm air stream is mixed with a cold fresh air stream upstream of the catalytic converter to set a specific temperature.

[0005] The object of the present invention is to create an internal combustion engine and a motor vehicle such that the heating of an exhaust aftertreatment device can be carried out particularly advantageously and particularly quickly.

[0006] This problem is solved according to the invention by an internal combustion engine with the features of claim 1 and by a motor vehicle with the features of claim 8. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0007] A first aspect of the invention relates to an internal combustion engine for a motor vehicle, which can be driven by the internal combustion engine via an output shaft of the internal combustion engine. The internal combustion engine has at least one combustion chamber and an intake tract through which air can flow, wherein air can be supplied to the combustion chamber via the intake tract. Furthermore, the internal combustion engine comprises an exhaust tract through which an exhaust gas from the combustion chamber can flow, wherein an exhaust aftertreatment device for aftertreating the exhaust gas is arranged in the exhaust tract.

[0008] Furthermore, at least one heating element for heating a gas flowing through the exhaust system is arranged in the exhaust tract upstream of the exhaust aftertreatment system. The internal combustion engine comprises an electrically assisted exhaust turbocharger, which has a compressor wheel arranged in the intake tract as its first impeller for compressing the air flowing through the intake tract. The electrically assisted exhaust turbocharger also has a turbine wheel arranged in the exhaust tract and driven by the exhaust gas as its second impeller, as well as an electric motor. In heating mode, the electric motor can drive at least one of the two impellers to heat the exhaust aftertreatment system. During heating mode, when combustion processes in the combustion chamber are suspended and the output shaft is stationary, air can be pumped into the exhaust tract as a heating medium by means of at least one impeller.The heating medium can be heated by the heating element to warm the exhaust gas aftertreatment system during heating operation. Thus, the heating medium could be, for example, a gas that can be heated by the heating element.

[0009] To enable particularly efficient and rapid heating of the exhaust aftertreatment system, the internal combustion engine, according to the invention, comprises at least one conduit element which is fluidically connected to the exhaust tract at a first connection point located downstream of the exhaust aftertreatment system and at a second connection point located upstream of the heating element. By means of the conduit element, at least a portion of the heating medium can be diverted from the exhaust tract at the first connection point, introduced into the conduit element, returned from the first connection point to the second connection point, and reintroduced into the exhaust tract at the second connection point. Furthermore, the internal combustion engine comprises a valve train which includes at least one intake valve and at least one exhaust valve associated with the combustion chamber.The intake and exhaust valves are collectively referred to as gas exchange valves. During heating operation, the intake and exhaust valves are open simultaneously, allowing the heating medium to flow from the intake manifold through the combustion chamber and thus, via the gas exchange valves, into the exhaust manifold. In other words, because the gas exchange valves are open at the same time, the intake valve opens an intake port, while simultaneously the exhaust valve opens an exhaust port of the internal combustion engine.The heating medium can now flow through the inlet channel and thereby flow into the combustion chamber via the inlet channel and the inlet valve from the intake tract and then flow through the combustion chamber and then flow through the exhaust channel and thereby flow into the exhaust tract via the exhaust channel and the exhaust valve, whereby the exhaust gas can be or is guided from the intake tract through the combustion chamber via the gas exchange valves into the exhaust tract.

[0010] The motor vehicle is preferably designed as a car, in particular as a passenger car. The internal combustion engine can be designed as a reciprocating piston engine and have an engine block that includes the combustion chamber. A fluid, typically air, flows into the combustion chamber via the intake manifold. During combustion, combustion processes take place in the combustion chamber. In each combustion process, a fuel-air mixture is burned, producing the exhaust gas of the internal combustion engine. The fuel-air mixture comprises the aforementioned air flowing through the intake manifold and a fuel, in particular a liquid, which is introduced into the combustion chamber, in particular by direct injection.

[0011] The exhaust gas aftertreatment device for aftertreating the exhaust gas is arranged in the exhaust tract, which can also be referred to in particular as the exhaust system. In other words, the exhaust gas aftertreatment device serves to purify the exhaust gas by means of, in particular, at least one catalyst and / or at least one filter such as, for example, a particulate filter. By means of the catalyst, pollutants present in the exhaust gas, such as, for example, carbon monoxide, nitrogen monoxide, nitrogen dioxide and / or unburned hydrocarbons, are converted into harmless substances by means of at least one chemical reaction. The catalyst can thus be designed as a three-way catalyst. The term catalyst is understood in particular to mean a component that particularly reduces the activation energy of the chemical reaction, whereby the reaction rate of the chemical reaction proceeds particularly quickly.Activation energy is, in particular, the amount of energy required to initiate a chemical reaction. The reaction rate is, in particular, the rate at which the chemical reaction proceeds. A filter is, in particular, a component that retains solids from a gas or liquid stream. This allows solid pollutants, especially particles or soot, to be filtered from the exhaust gas.

[0012] To ensure particularly effective exhaust gas purification from the internal combustion engine, it is advantageous for the exhaust aftertreatment system, especially the catalytic converter, to have a minimum temperature, which can be referred to as a conversion temperature, light-off temperature, or start-up temperature. This requires heating the exhaust aftertreatment system, particularly during a cold start. A cold start is defined as the commissioning, starting, or activation of the internal combustion engine at which the engine temperature is approximately equal to the ambient temperature.When the internal combustion engine is started, it is brought from a state in which combustion processes in the combustion chamber cease and the output shaft is stationary, which is also referred to as the engine being stopped, into an activated state, which is particularly referred to as fired operation. After a cold start, the exhaust gas aftertreatment device is heated up by the exhaust gas. In vehicles with a combination of an internal combustion engine and electric drive, heating up or keeping the exhaust tract warm using the exhaust gas is particularly difficult, since the mass flow of the exhaust gas can be very low or non-existent in some operating states. Electric driving is particularly the term used for electric travel of a motor vehicle, whereby during electric travel the motor vehicle is at least partially powered by an electric motor.

[0013] The heating element arranged in the exhaust tract upstream of the exhaust aftertreatment device can particularly accelerate the heating of the exhaust aftertreatment device, particularly after a cold start. The heating element is designed such that it heats the gas flowing through or around the heating element, such as the exhaust gas. During normal operation and / or a cold start of the internal combustion engine, this gas is the exhaust gas. During heating operation of the internal combustion engine, which differs from normal operation, the gas is the air, which is heated by the heating element and used as the heating medium to warm or heat the exhaust aftertreatment device.

[0014] To enable particularly advantageous and rapid heating of the exhaust aftertreatment system, the inventive duct element and the inventive valve train, which can be designed in particular as a variable or fully variable valve train, are provided. A variable or fully variable valve train is understood to be a valve train in which a valve stroke or an opening duration, in particular an opening time and / or a closing time, of the inlet valve and / or the outlet valve can be variably adjusted or changed. This can be done in particular during normal operation and / or during heating operation.In heating mode, the inlet valve and the outlet valve are at least partially open simultaneously, whereby the heating medium can be conveyed, for example by means of the electric or electrically assisted exhaust gas turbocharger, from the intake tract through the combustion chamber into the exhaust tract to the heating element and / or the heating medium can be conveyed in the exhaust tract and circulate, in particular via the conduit element. In this case, at least one of the two impellers is driven by the electric machine using electrical energy, which can be taken in particular from a power supply device referred to as the on-board electrical system. By means of the conduit element, at least a portion of the heating medium heated by the heating element can be returned to the heating element and the exhaust gas aftertreatment device after flowing through the exhaust gas aftertreatment device, thereby creating a recirculation circuit.In this way, not only the exhaust aftertreatment system is heated, but also other parts of the exhaust system. This results in a particularly low temperature gradient between the exhaust aftertreatment system and its surrounding components, meaning that very little heat is transferred from the aftertreatment system to the surrounding components. In other words, heat loss from the exhaust aftertreatment system is extremely low. This allows for highly efficient heating and maintaining of the exhaust aftertreatment system. Furthermore, the heating medium can be brought to a very high temperature in a short time, enabling efficient and effective heating of the exhaust aftertreatment system. The recirculation circuit can be operated, in particular, when the engine is off.The heating medium can be pumped or at least supported in the recirculation circuit, in particular by means of the electrically driven impeller, or especially by means of the second impeller. In other words, the recirculation circuit can be maintained by means of the electrically driven impeller. This enables conditioning of the exhaust aftertreatment system, especially when the engine is off. As a result, the internal combustion engine emits particularly few pollutants, especially after a cold start.

[0015] In one embodiment of the invention, a valve element is arranged in the pipe element, by means of which the amount of heating medium flowing through the pipe element can be adjusted. For this purpose, the valve element can be connected to a control device, which is, for example, represented by a control unit or also referred to as a control unit. The pipe element can be partially or completely closed by means of the valve element.

[0016] According to the invention, the internal combustion engine has an exhaust gas recirculation line which is fluidically connected to the exhaust tract at a branch point located downstream of the turbine wheel, in particular downstream of the exhaust aftertreatment system. The exhaust gas recirculation line is also fluidically connected to the intake tract at an inlet point. The inlet point is located downstream of the compressor wheel. At least a portion of the exhaust gas from the branch point can be diverted from the exhaust tract and introduced into the exhaust gas recirculation line. The exhaust gas introduced into the exhaust gas recirculation line can flow through it and is guided to the inlet point, where it is introduced into the intake tract. This can be described, in particular, as low-pressure exhaust gas recirculation. This allows the exhaust gas to be directed into the combustion chamber.A portion of exhaust gas already present in the combustion chamber before the combustion process begins can significantly reduce the amount of a pollutant that can be formed during the combustion process. This can be, in particular, nitrogen monoxide or nitrogen dioxide, both of which are generally referred to as nitrogen oxides. During heating operation, for example, at least a portion of the heating medium can be routed from the branch point to the inlet point and introduced into the intake tract at the inlet point.

[0017] In another embodiment, an exhaust gas recirculation valve is arranged in the exhaust gas recirculation line, by means of which the amount of exhaust gas and / or heating medium flowing through the exhaust gas recirculation line can be adjusted. For this purpose, the exhaust gas recirculation valve can be connected to the control unit and controlled and thus operated by the control unit. The exhaust gas recirculation line can, for example, be partially or completely closed off by means of the exhaust gas recirculation valve.

[0018] Another embodiment is characterized in that the internal combustion engine has a return line which is fluidically connected to the exhaust tract at a third connection point located upstream of the turbine wheel and to the intake tract at a fourth connection point. The fourth connection point is preferably located downstream of the compressor wheel. By means of the return line, at least a portion of the exhaust gas flowing through the exhaust tract can, for example, be diverted from the exhaust tract and introduced into the return line. The exhaust gas introduced into the return line can flow through the return line in a first flow direction and is thereby guided by the return line from the third connection point to the fourth connection point and introduced into the intake tract at the fourth connection point, which can be described in particular as high-pressure exhaust gas recirculation.During heating operation, at least part or all of the heating medium can be branched off from the intake tract at the fourth connection point and fed into the return line. The exhaust gas fed into the return line can flow through the return line in a second flow direction opposite to the first flow direction and is guided via the return line from the fourth connection point to the third connection point. The heating medium is guided from the intake tract into the exhaust tract to the heating element, bypassing the combustion chamber or all combustion chambers of the internal combustion engine, whereby the heating medium and consequently the exhaust gas aftertreatment system can be heated particularly effectively.

[0019] In a further embodiment of the invention, a return valve is arranged in the return line, by means of which the amount of exhaust gas and / or heating medium flowing through the return line can be adjusted. For this purpose, the return valve can be connected to the control unit and controlled by it. The return line can be partially or completely closed off, for example, by means of the return valve.

[0020] Finally, it has proven particularly advantageous if the heating element comprises at least one electric heating element and / or at least one burner and / or at least one electric catalyst. An electric heating element is understood to be, in particular, a heating element that converts electric current into heat. A burner is understood to be, in particular, a heating element in which at least one fuel, especially liquid or gaseous, is combusted, either with the formation of a flame or flamelessly and thus catalytically, particularly with the release or emission of heat. An electric catalyst is understood to be, in particular, a catalyst that is heated or can be heated by means of an electric heating element, wherein the electric heating element may, for example, be attached to a housing of the catalyst and / or be connected to a catalytic or catalytically active structure of the catalyst.

[0021] A second aspect of the invention relates to a motor vehicle comprising an internal combustion engine according to the first aspect of the invention. 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. The motor vehicle according to the invention is preferably configured as a motor vehicle, in particular as a passenger car or truck, or as a passenger bus or motorcycle.

[0022] Further advantages, features, and details of the invention will become apparent from the following description of preferred embodiments 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 specified combination, but also in other combinations or on their own, without departing from the scope of the invention.

[0023] The drawing shows in the single figure a schematic representation of an internal combustion engine according to the invention.

[0024] The single figure schematically shows an internal combustion engine 10 for a motor vehicle, in particular for a motor vehicle preferably designed as a passenger car. The motor vehicle can be driven by means of the internal combustion engine 10. The internal combustion engine 10 has an intake manifold 12, at least one cylinder, and an exhaust manifold 16. The cylinder partially defines a combustion chamber 14. The internal combustion engine 10 has a piston which is movably mounted in the cylinder. The piston partially defines the combustion chamber 14. In the embodiment shown in the figure, it is a four-cylinder engine comprising exactly four combustion chambers 14.

[0025] The inlet tract is permeable to a fluid in the form of air, which is guided into the combustion chamber 14 via the intake tract. During operation of the internal combustion engine 10, combustion processes take place in the combustion chamber 14, resulting in exhaust gas from the internal combustion engine 10. The exhaust gas can flow through the exhaust tract 12, also referred to as the exhaust system, and exit the combustion chamber 14 via the exhaust tract 12. At least one heating element 18 and an exhaust aftertreatment device 20 are arranged in the exhaust tract 16, with the heating element 18 being located upstream of the exhaust aftertreatment device 20. The exhaust aftertreatment device 20 comprises at least one element for exhaust gas purification.The element for exhaust gas purification can be designed, for example, as an oxidation catalyst, in particular a diesel oxidation catalyst (DOC), as a NOx storage catalyst (NSK), as an SCR catalyst (Selective Catalytic Reduction Catalyst), as a diesel particulate filter (DPF) or as an SCR catalyst on a diesel particulate filter (SDPF).

[0026] An oxidation catalyst is specifically defined as a catalyst that removes carbon monoxide and unburned hydrocarbons from the exhaust gas via oxidation with residual oxygen. Residual oxygen refers specifically to oxygen molecules that were not part of a chemical reaction during combustion and are therefore available as oxygen for further chemical reactions. A NOx storage catalyst (NSC) is specifically understood to be a catalyst that incorporates a storage component in which nitrogen oxides are chemically bound and thus removed from the exhaust gas. Subsequently, in an operating condition of the internal combustion engine characterized by oxygen deficiency in the exhaust gas, the nitrogen oxides can be released from the storage component and reduced by reducing components such as unburned hydrocarbons or carbon monoxide.An SCR catalyst is specifically a catalyst in which nitrogen oxides are reacted with urea from an introduced urea solution to form nitrogen and water in a redox reaction. A diesel particulate filter (DPF) is specifically understood to be a filter that removes particles, also known as soot or particulate matter, from the exhaust gas.

[0027] The internal combustion engine 10 also features an electric, electrically assisted, or electrically assisted exhaust gas turbocharger 22, which comprises a compressor wheel arranged in the intake tract 12 as the first impeller 24, a turbine wheel arranged in the exhaust tract 16 as the second impeller 26, and a shaft. The first impeller 24 and the second impeller 26 are arranged on the shaft and are rotationally fixed to the shaft. The first impeller 24, the second impeller 26, and the shaft are, for example, separately designed components that are connected to each other in such a way that relative rotations between the components, as well as movements relative to each other in the axial and radial directions of the shaft, are prevented or avoided. The first impeller 24 is used, for example, to compress the air supplied to the combustion chamber 14 via the intake tract 12.The second impeller 26, for example, expands the exhaust gas flowing from the combustion chamber 14 into the exhaust tract 16, thereby driving the second impeller 26. Furthermore, the internal combustion engine 10 includes an electric motor that can drive the exhaust gas turbocharger 22 using electrical energy. The electric motor can be configured to drive the shaft of the exhaust gas turbocharger 22, so that the first impeller 24 and the second impeller 26 are driven by the shaft. Alternatively, the electric motor can be configured so that the first impeller 24 and / or the second impeller 26 can be driven directly by the electric motor. This means that the shaft is not directly driven by the electric motor.The internal combustion engine 10 also has an output shaft, for example a crankshaft, via which the internal combustion engine can provide torque for driving the motor vehicle, particularly during the combustion engine's operation. During heating operation of the internal combustion engine 10, air is supplied as a heating medium to the exhaust tract 16 by means of the electrically assisted exhaust gas turbocharger 22, whereby at least one of the two impellers 24, 26 is electrically driven by the electric motor. During heating operation, combustion processes cease in the combustion chambers 14 of the internal combustion engine, and the output shaft remains stationary. Furthermore, during heating operation, the heating medium is heated by means of the heating element 18, so that the exhaust aftertreatment system 20 is heated by means of the heated heating medium.

[0028] In order to be able to heat the exhaust gas aftertreatment device 20 particularly advantageously and particularly quickly, the internal combustion engine 10 has a valve train which has at least one inlet valve assigned to the combustion chamber 14 and at least one outlet valve assigned to the combustion chamber 14. In heating mode, the inlet valve and the outlet valve are opened simultaneously, whereby in heating mode the heating medium can be guided from the intake tract 12 through the combustion chamber into the exhaust tract 16. The heating medium is accordingly conveyed from the intake tract 12, through the combustion chamber, into the exhaust tract 16 by means of the electrically driven exhaust gas turbocharger 22, wherein at least one of the two impellers 24, 26 is electrically driven.The internal combustion engine 10 also has at least one conduit element 28, which is fluidically connected to the exhaust gas tract 16 at a first connection point 30 located downstream of the exhaust aftertreatment device 20 and at a second connection point 32 located upstream of the heating element 18, in particular upstream of the turbine wheel 26. By means of the conduit element 28, at least a portion of the heating medium flowing through the exhaust gas tract 16 can be diverted from the exhaust gas tract 16 at the first connection point 30 and returned from the first connection point 30 to the second connection point 32, and introduced into the exhaust gas tract 16 at the second connection point 32. This allows for the return of the heating medium, since the heating medium is returned by means of the conduit element 28 from the first connection point 30 to the second connection point 32, which is located upstream, and introduced into the exhaust gas tract 16.This recirculation of the heating medium creates a first recirculation circuit in which the heating medium can circulate between the connection points 30 and 32. The first recirculation circuit can be operated by means of the electrically driven exhaust gas turbocharger 22, particularly in a state referred to as a stationary engine. This allows the exhaust aftertreatment system 20 to be heated and thus conditioned particularly effectively even when the engine is stationary. As a result, the internal combustion engine 10 exhibits particularly low emissions of pollutants. The stationary engine is defined as a situation where no combustion processes take place in the internal combustion engine 10 and the output shaft is at rest.

[0029] A valve element 34 is arranged in the pipe element 28, by means of which the amount of heating medium flowing through the pipe element 28 can be adjusted. For this purpose, the valve element 28 can be connected to a control device, which is, for example, a control unit.

[0030] By means of an exhaust valve element 35 arranged in the exhaust tract 16 downstream of the first connection point 30, which is designed, for example, as an exhaust flap, a mass flow of exhaust gas and / or heating medium leaving the internal combustion engine 10 can be reduced, prevented, or dammed. To set a defined mass flow, the exhaust valve element 35 can be connected to a control device, which is, for example, a control unit and can actuate the exhaust valve element 35 and thereby operate it, in particular control or regulate it. By at least partially closing the exhaust tract 16 by means of the exhaust valve element 35, it can be ensured that a particularly large quantity of the heating medium flows through the recirculation circuit, i.e., circulates via or along the recirculation circuit.The recirculation circuit includes the conduit element 28, such that the heating medium flowing through the recirculation circuit flows through the conduit element 28 and thus circulates via the conduit element 28. This circulation or recirculation allows the exhaust gas aftertreatment device 20 to be heated particularly quickly and effectively.

[0031] The internal combustion engine 10 has an exhaust gas recirculation line 36. The exhaust gas recirculation line 36 is fluidically connected to the exhaust tract 16 at a branch point 38 arranged downstream of the exhaust aftertreatment device 20. Furthermore, the exhaust gas recirculation line 36 is fluidically connected to the intake tract 12 at an inlet point 40. By means of the exhaust gas recirculation line 36, particularly during fired operation, at least a portion of the exhaust gas flowing through the exhaust tract 16 can be guided from the branch point 38 to the inlet point 40 and introduced into the intake tract 12 at the inlet point 40. The inlet point is arranged in the intake tract downstream of the first impeller 24, but can alternatively be arranged upstream of the first impeller 24, which is not shown in the figure.During heating operation, at least a portion of the heating medium can be routed from branch point 38 to inlet point 40 and introduced into the intake tract 12 at inlet point 40. Thus, a second recirculation circuit of the heating medium can be established via the exhaust gas recirculation line 36 during heating operation. The heating medium is pumped by the electrically driven first impeller 24 and / or the electrically driven second impeller 26 of the exhaust gas turbocharger 22. The second recirculation circuit can be operated independently of the first recirculation circuit or in conjunction with it. An exhaust gas recirculation valve 42 is located in the exhaust gas recirculation line 36, allowing the flow rate of exhaust gas and / or heating medium through the exhaust gas recirculation line 36 to be adjusted. For this purpose, the exhaust gas recirculation valve 42 can be connected to a control device, such as the control unit.

[0032] The internal combustion engine 10 has a return line 44 which is fluidically connected to the exhaust tract at a third connection point 46 located upstream of the second impeller 26 and to the intake tract 12 at a fourth connection point 48. The fourth connection point 48 is preferably located downstream of the first impeller 24. At least a portion of the exhaust gas can be guided in a first flow direction from the third connection point 46 to the fourth connection point 48 via the return line 44 and introduced into the intake tract 12 at the fourth connection point 48. During heating operation, the heating medium can be guided in a second flow direction, opposite to the first flow direction, from the fourth connection point 48 to the third connection point 46 and introduced into the exhaust tract 16 at the third connection point 46.The heating medium is conveyed from the intake manifold to the heating element 18 by means of at least the electrically driven first impeller 24, bypassing the combustion chamber 14. A return valve 50 is arranged in the return line 44, by means of which the amount of exhaust gas or heating medium flowing through the return line 44 can be adjusted. For this purpose, the return valve 50 can be connected to a control device, which is represented, for example, by the control unit.

[0033] The heating element 18 can include an electric heating element and / or a burner and / or an electrically heated catalyst. List of reference symbols

[0034] 10 Internal combustion engine 12 Intake manifold 14 Combustion chamber 16 Exhaust manifold 18 Heating element 20 Exhaust aftertreatment system 22 Exhaust turbocharger 24 Compressor wheel 26 Turbine wheel 28 Line element 30 First connection point 32 Second connection point 34 Valve element 35 Exhaust valve element 36 Exhaust gas recirculation line 38 Extraction point 40 Inlet point 42 Exhaust gas recirculation valve 44 Recirculation line 46 Third connection point 48 Fourth connection point 50 Recirculation valve

Claims

1. Internal combustion engine (10) for a motor vehicle, comprising an output shaft via which the motor vehicle can be driven by means of the internal combustion engine (10), comprising an intake tract (12) through which air to be supplied to at least one combustion chamber (14) of the internal combustion engine (10) can flow, comprising an exhaust tract (16) through which exhaust gas from the combustion chamber (14) can flow, comprising an exhaust aftertreatment device (20) arranged in the exhaust tract for aftertreatment of the exhaust gas, comprising at least one heating element (18) arranged in the exhaust tract (16) upstream of the exhaust aftertreatment device (20) for heating a gas flowing through the exhaust tract (16), and comprising an electrically assisted exhaust gas turbocharger (22), which has a compressor wheel arranged in the intake tract (12) as a first impeller (24) for compressing the air flowing through the intake tract (12) and a turbine wheel which is arranged in the exhaust tract (16) and can be driven by the exhaust gas as a second impeller (26), and an electric machine by means of which at least one of the impellers (24, 26) can be driven in a heating mode for heating up the exhaust gas aftertreatment device (20), whereby in the heating mode, during which combustion processes in the combustion chamber (14) are stopped and the output shaft is stationary, air can be conveyed into the exhaust tract (16) as a heating medium by means of the at least one impeller (24, 26), which air can be heated by means of the heating element (18) in the heating mode for heating up the exhaust gas aftertreatment device (20), wherein an exhaust gas recirculation line (36) is provided which is fluidically connected to the exhaust tract (16) at a branch point (38) arranged downstream of the turbine wheel (26) and is fluidically connected to the intake tract (12) at an inlet point (40), whereby at least part of the exhaust gas and / or in the heating mode at least part of the heating medium can be conveyed from the branch point (38) to the inlet point (40) and can be introduced into the intake tract (12) at the inlet point (40) characterized by at least one line element (28) which is fluidically connected to the exhaust tract (16) at a first connection point (30) arranged downstream of the exhaust gas aftertreatment device (20) and at a second connection point (32) arranged upstream of the heating element (18), whereby at least part of the heating medium can be returned from the first connection point (30) to the second connection point (32) and introduced into the exhaust tract (16) at the second connection point (32), wherein the internal combustion engine (10) has a valve train which has at least one inlet valve assigned to the combustion chamber (14) and at least one outlet valve assigned to the combustion chamber (14), and wherein in the heating mode the inlet valve and the outlet valve are opened simultaneously, whereby in the heating mode the heating medium can be conveyed from the intake tract (12) through the combustion chamber (14) into the exhaust tract (16), and wherein the inlet point (40) of the exhaust gas recirculation line (36) is arranged downstream of the compressor wheel (24).

2. Internal combustion engine (10) according to claim 1, characterized by a valve element (34) arranged in the line element (28), by means of which a quantity of the heating medium that can flow through the line element (28) can be adjusted.

3. Internal combustion engine (10) according to claim 1 or 2, characterized by an exhaust gas recirculation valve (42) arranged in the exhaust gas recirculation line (36), by means of which a quantity of the exhaust gas and / or the heating medium that can flow through the exhaust gas recirculation line (36) can be adjusted.

4. Internal combustion engine (10) according to any one of the preceding claims, characterized by a return line (44) which is fluidically connected to the exhaust tract (16) at a third connection point (46) arranged upstream of the turbine wheel (26) and is fluidically connected to the intake tract (12) at a fourth connection point (48), whereby at least part of the exhaust gas can be conveyed from the third connection point (46) to the fourth connection point (48) and introduced into the intake tract (12) at the fourth connection point (48) and / or in the heating mode at least part of the heating medium can be conveyed from the fourth connection point (48) to the third connection point (46) and introduced into the exhaust tract (16) at the third connection point (46).

5. Internal combustion engine (10) according to claim 4, characterized in that the fourth connection point (48) is arranged downstream of the compressor wheel (22).

6. Internal combustion engine (10) according to claim 4 or 5, characterized by a return valve (50) arranged in the return line (46), by means of which a quantity of the exhaust gas and / or the heating medium that can flow through the return line (44) can be adjusted.

7. Internal combustion engine (10) according to any one of the preceding claims, characterized in that the heating element (18) has at least one electric heating element and / or a burner.

8. Motor vehicle comprising an internal combustion engine (10) according to any one of the preceding claims.