Internal combustion engine for a motor vehicle, in particular for a motor car, as well as motor vehicle

Abstract

Internal combustion engine (10) for a motor vehicle, comprising an intake manifold (18) through which air flows, by means of which the air flowing through the intake manifold (18) is to be guided into at least one combustion chamber (16) of the internal combustion engine (10), an exhaust manifold (24) through which exhaust gas flows from the combustion chamber (16), an exhaust gas turbocharger (26) which has a turbine wheel (30) arranged in the exhaust manifold (24) and driven by the exhaust gas and a compressor wheel (28) arranged in the intake manifold (18) and driven by the turbine wheel (30) for compressing the air, and a low-pressure exhaust gas recirculation device (38) which has at least one recirculation line (40) by means of which at least a part of the exhaust gas flowing through the exhaust manifold (24) can be diverted from the exhaust manifold (24) at a branch point (A) arranged downstream of the turbine wheel (30),The exhaust gas recirculation system (38) is recirculated to the intake tract (18) and can be introduced into the intake tract (18) at an inlet point (E), characterized in that at least one valve element (44) is arranged in the recirculation line (40), which is designed as a Tesla valve, wherein the low-pressure exhaust gas recirculation system (38) has an exhaust gas recirculation cooler (42) arranged in the recirculation line (40) for cooling the exhaust gas to be recirculated, and wherein the exhaust gas recirculation cooler (42) has several cooling channels (50) through which the exhaust gas to be recirculated can flow, wherein a respective valve element (44) is arranged in the respective channel (50), which is designed as a Tesla valve.

Description

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

[0002] DE 10 2018 107 436 A1 discloses an internal combustion engine with high-pressure exhaust gas recirculation, which includes a recirculation valve for controlling the amount of exhaust gas recirculated into a fresh air intake. DE 10 2018 106 679 A1 further discloses a method for operating an internal combustion engine. DE 10 2006 053 710 A1 also discloses an internal combustion engine with a compressor in the intake manifold. DE 10 2019 217 473 A1 discloses an internal combustion engine. JP 2012-52450 A discloses an exhaust gas recirculation device as known. In DE 10 2010 054 644 A1, an exhaust gas recirculation device for an internal combustion engine is disclosed, comprising an exhaust gas heat exchanger and an aftercooler housing, wherein at least one exhaust gas check valve is attached directly to the aftercooler housing.

[0003] The object of the present invention is to create an internal combustion engine for a motor vehicle and a motor vehicle with such an internal combustion engine, so that particularly high exhaust gas recirculation rates can be achieved in a particularly simple way.

[0004] This problem is solved by an internal combustion engine with the features of claim 1 and by a motor vehicle with the features of claim 7. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0005] A first aspect of the invention relates to an internal combustion engine, also known as a combustion engine, and for example a reciprocating piston engine, for a motor vehicle, in particular for a car and especially for a passenger car. This means that the motor vehicle, in its fully manufactured state, has an internal combustion engine and can be driven by means of this engine. The internal combustion engine has an intake manifold, also referred to as an intake tract, through which air flows into at least one combustion chamber of the internal combustion engine. During operation of the internal combustion engine, combustion processes take place in the combustion chamber. In each combustion process, a fuel-air mixture, also simply called a mixture, is burned. This results in exhaust gas from the internal combustion engine.The mixture includes, for example, the air that is drawn into the combustion chamber via the intake manifold, as well as a fuel, for example, a liquid fuel. In particular, the fuel can be gasoline, so the internal combustion engine can be designed, for example, as a gasoline engine.

[0006] The internal combustion engine also has an exhaust tract through which the exhaust gas from the combustion chamber flows. The internal combustion engine also includes an exhaust gas turbocharger, which has a turbine wheel located in the exhaust tract and driven by the exhaust gas. The exhaust gas turbocharger also has a compressor wheel located in the intake tract, which is driven by the turbine wheel. By driving the compressor wheel, the air flowing through the intake tract can be compressed. The internal combustion engine also has a low-pressure exhaust gas recirculation system, by means of which low-pressure exhaust gas recirculation (LP-EGR) can be carried out.The low-pressure exhaust gas recirculation (LPR) system, hereinafter also referred to simply as an exhaust gas recirculation system, has at least one recirculation line, also referred to as an exhaust gas recirculation line, by means of which at least a portion of the exhaust gas flowing through the exhaust tract can be diverted from the exhaust tract at a branch point located downstream of the turbine wheel, recirculated back to the intake tract, and introduced into the intake tract at an inlet point. This means that the exhaust gas diverted from the exhaust tract at the branch point can flow into the recirculation line and subsequently flow through the recirculation line, being returned to the intake tract and introduced into the intake stroke.

[0007] In order to achieve particularly high exhaust gas recirculation rates (EGR rates), i.e., particularly large quantities of exhaust gas to be recirculated, in a particularly simple manner that is also particularly lightweight, space-saving, and cost-effective, the invention provides that at least one valve element is arranged in the recirculation line. According to the invention, this valve element is designed as a Tesla valve and, alternatively, could also be designed as a check valve. The check valve is understood to be a valve that has a valve part, also referred to as the valve body, which is movable, particularly relative to the recirculation line and thus, for example, relative to a valve housing of the valve element. This valve part is movable between a closed position and at least one open position, particularly rotationally and / or translationally, relative to the recirculation line and thus, in particular, relative to the valve housing.For example, the valve part can be moved exclusively by rotation between the closed and open positions, i.e., pivoted. Furthermore, it is conceivable that the valve part can be moved exclusively by translation between the open and closed positions. For example, the check valve can be designed as a reed valve. It is also conceivable that the check valve is designed as a ball valve, i.e., a ball check valve, so that the valve is then, for example, a sphere, also referred to as a valve ball. In particular, the check valve is a valve that opens and closes automatically without any other external actuator and solely due to pressure differences or flow directions, such as when a fluid, like gas, flows through the return line.In the closed position of the valve assembly, the check valve closes the return line, meaning it is fluidically blocked, preventing exhaust gas from flowing through the return line in a first direction. In the open position, the valve assembly, and thus the check valve, releases the return line, also known as the exhaust gas recirculation line, allowing exhaust gas to flow through the return line in a second direction opposite to the first. For example, on its way from the branch point to the inlet, the exhaust gas flows in the second direction, meaning it flows through the return line along this second direction, midway through its journey from the exhaust manifold to the intake manifold.In the first flow direction, the exhaust gas would flow through the return line from the inlet towards the branch point or to the branch point. However, such a flow of exhaust gas in the first flow direction through the return line can be prevented, i.e., blocked, by the check valve. Thus, the check valve or valve component is opened by an exhaust gas flow in the return line in the second flow direction, moving it from the closed position to the open position. If there is no exhaust gas flow in the second flow direction, or if the flow is only slight, or if the exhaust gas exerts only a slight pressure on the valve component in the second flow direction, the check valve closes automatically, in particular by means of a spring force acting in or on the valve component.For example, the spring force is provided by a return spring, particularly a mechanical one, of the check valve. Furthermore, it is conceivable that the valve part, especially if the check valve is designed as a reed valve, is elastically deformed in the open position, so that the spring force acts in the valve part, by means of which the valve part can be moved from the open position to the closed position, thereby closing the check valve.

[0008] The Tesla valve is a passive valve without moving mechanical components, which has a first flow resistance along one of the flow directions and a second resistance along the other flow direction that is greater than the first flow resistance, especially for the exhaust gas.

[0009] The invention makes it possible to utilize pressure fluctuations of the exhaust gas in the exhaust system, also known as the exhaust tract, to achieve particularly high exhaust gas recirculation rates, and thus to recirculate particularly large quantities of exhaust gas. The invention is based in particular on the following findings and considerations: In low-pressure exhaust gas recirculation (LP-EGR), in certain areas of the engine operating map, the pressure difference between the exhaust gas extraction point (also known as the branch point) and the inlet point (also known as the injection point) may be too small to achieve a sufficiently high exhaust gas recirculation rate. Previously, attempts were made to equip an EGR system, and thus, for example, the recirculation line, with a sufficiently large cross-section through which the recirculated exhaust gas could flow, and with good flow guidance.Nevertheless, it is usually necessary to install an exhaust flap or other backflow preventer in the exhaust system, particularly downstream of the branch point, to stagnate the exhaust gas flowing through the system, especially at a point downstream of the branch point, and consequently achieve high exhaust gas recirculation rates. Large cross-sections of the EGR system result in a large installation space requirement for the exhaust gas recirculation device, necessitating complex and detailed design and calculations. Large EGR valves are typically required, which are complex in their construction and very difficult to precisely control at operating points with high differential pressure.The additional exhaust flap or backflow preventer used in the exhaust system is expensive and often difficult to install. Furthermore, it is prone to failure, particularly because it is exposed to the hot exhaust gas flowing through the exhaust system. The invention avoids these problems and disadvantages. The valve element utilizes pressure fluctuations in the exhaust gas, also known as pulsations, which occur in the exhaust system. This allows for the adjustment of the amount of exhaust gas to be recirculated, also referred to as exhaust gas flow rate, to a suitably high value, especially when the pressure difference between the branch point and the inlet is low or medium. This eliminates the need for a costly, space-consuming, and failure-prone backflow preventer in the exhaust system.An EGR valve used to regulate the amount of recirculated exhaust gas can be designed smaller and therefore more cost-effective compared to conventional solutions, resulting in improved control characteristics, especially at high pressure differentials between the branch point and the inlet point. Particularly when the valve element is designed as the aforementioned Tesla valve, which has no moving parts, a particularly simple and thus cost-effective and space-saving design can be achieved. Furthermore, this reduces the susceptibility to defects, especially compared to reed or flapper valves.

[0010] In order to be able to recirculate the exhaust gas in a particularly advantageous way, it is provided that the exhaust gas recirculation device has an exhaust gas recirculation cooler arranged in the recirculation line and also referred to as an EGR cooler, by means of which the exhaust gas to be recirculated, flowing through the recirculation line, can be cooled.

[0011] To minimize the installation space and costs of the exhaust gas recirculation system while simultaneously achieving particularly high exhaust gas recirculation rates, a further embodiment of the invention provides that the valve element is designed as a Tesla valve. This valve exhibits a first flow resistance for the exhaust gas flowing towards the inlet point in the exhaust gas recirculation line (i.e., flowing in the second direction of flow) and a second flow resistance that is significantly greater than the first for the exhaust gas flowing towards the branch point in the exhaust gas recirculation line. This allows backflow of exhaust gas towards the branch point to be at least limited, and in particular avoided.In other words, the Tesla valve preferably causes a first pressure drop in the exhaust gas flowing towards the inlet point, and thus in the second flow direction, through the return line and therefore through the Tesla valve. For example, the Tesla valve causes a second pressure drop in the exhaust gas flowing towards the branch point, and thus in the first flow direction, through the return line and therefore through the Tesla valve, where the second pressure drop is, in particular, significantly greater than the first pressure drop. This prevents excessive backflow of the exhaust gas in the return line towards the branch point or in the first flow direction.

[0012] Another embodiment is characterized in that the exhaust gas recirculation device has an exhaust gas recirculation valve arranged in the recirculation line and provided in addition to the valve element, by means of which the quantity of exhaust gas to be recirculated can be adjusted. In particular, the exhaust gas recirculation valve is electrically operable, and thus electrically controllable. For example, by electrically controlling the exhaust gas recirculation valve and thus using electrical energy, the flow cross-section of the exhaust gas flowing through the exhaust gas recirculation valve can be adjusted, i.e., varied, thereby allowing the quantity of exhaust gas to be adjusted particularly according to demand, especially to different values, particularly higher than zero. This enables a particularly advantageous low-pressure exhaust gas recirculation system.

[0013] It has proven particularly advantageous to arrange the exhaust gas recirculation valve downstream of the valve element in the direction of flow of the exhaust gas flowing towards the inlet point, i.e., in the direction of flow of the exhaust gas flowing in the second direction. This allows the required installation space to be kept to a particularly small level.

[0014] Another embodiment provides that the exhaust gas recirculation valve is arranged downstream of the exhaust gas recirculation cooler in the direction of flow of the exhaust gas flowing towards the inlet point, which allows for a particularly compact and cost-effective design of the exhaust gas recirculation system.

[0015] Finally, it has proven particularly advantageous for achieving especially high exhaust gas recirculation rates if the inlet point is arranged upstream of the compressor wheel in the direction of flow of the air flowing through the intake tract and towards the combustion chamber.

[0016] A second aspect of the invention relates to a motor vehicle, preferably designed as a motor car, in particular as a passenger car, with 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.

[0017] 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 those mentioned below in the figure description and / or shown in the figures alone, can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention.

[0018] The drawing shows in: Fig. 1 a schematic representation of an internal combustion engine for a motor vehicle; Fig. 2 a schematic perspective view of an exhaust gas recirculation cooler of an exhaust gas recirculation device of an internal combustion engine according to an embodiment of the invention; and Fig. 3. Partial schematic sectional view of the exhaust gas cooler along a [path] Fig. 2 shown section line AA.

[0019] In the figures, identical or functionally equivalent elements are provided with the same reference numerals.

[0020] Fig. Figure 1 shows a schematic representation of an internal combustion engine 10 for a motor vehicle, in particular for a car. The internal combustion engine 10 has an engine housing 12, designed, for example, as a cylinder housing, in particular as a cylinder crankcase, by which several cylinders 14 are formed, i.e., delimited. Each cylinder 14 partially delimits a respective combustion chamber 16 of the internal combustion engine 10. During firing operation of the internal combustion engine 10, combustion processes take place in the combustion chambers 16. In each combustion process, a fuel-air mixture is burned, resulting in exhaust gas from the internal combustion engine 10. The internal combustion engine 10 has an intake manifold 18 through which air flows, and by means of which the air flowing through the intake manifold 18, also referred to as fresh air, is directed to and into the combustion chambers 16.The respective fuel-air mixture comprises the air that is directed into the combustion chambers 16 via the intake tract 18. The respective fuel-air mixture also comprises a fuel, in particular a liquid, which is introduced into the respective combustion chamber 16, in particular by direct injection. A charge air distributor 20, which will be explained in more detail below, is arranged upstream of the combustion chamber 16 in the intake tract 18. Furthermore, an air filter 22 is arranged upstream of the charge air distributor 20 in the intake tract 18, by means of which the air flowing through the intake tract 18 is filtered.

[0021] The internal combustion engine 10 also has an exhaust tract 24, also referred to as an exhaust system, through which the exhaust gas from the combustion chambers 16 flows. Furthermore, the internal combustion engine 10 has an exhaust gas turbocharger 26. The exhaust gas turbocharger 26 has a compressor wheel 28 arranged in the intake tract 18, particularly downstream of the air filter 22 and downstream of the charge air distributor 20. The exhaust gas turbocharger 26 also includes a turbine wheel 30, which is arranged in the exhaust tract 24. The exhaust gas turbocharger 26 also has a shaft 32. The turbine wheel 30 is driven by the exhaust gas flowing through the exhaust tract 24 and is therefore rotatable, particularly relative to a turbine housing of the exhaust gas turbocharger 26. The compressor wheel 28 can be driven by the turbine wheel 30 via the shaft 32 and thereby rotated, in particular relative to a compressor housing of the exhaust gas turbocharger 26.By driving the compressor wheel 28, the air flowing through the intake tract 18 is compressed. The compressed air is also referred to as charge air. The charge air is distributed or divided among the combustion chambers 16 by means of the charge air distributor 20.

[0022] In the intake tract 18, a charge air cooler 34 is arranged downstream of the compressor wheel 28 and upstream of the charge air distributor 20. This cooler cools the compressed and thus heated air before it flows into the combustion chambers 16. In the exhaust tract 24, downstream of the turbine wheel 30, an exhaust aftertreatment device 36 is arranged for treating the exhaust gas in the direction of flow of the exhaust gas flowing through the exhaust tract 24 and away from the combustion chambers 16.

[0023] The internal combustion engine 10 also has a low-pressure exhaust gas recirculation device 38 (LP EGR device) by means of which low-pressure exhaust gas recirculation (LP EGR) can be carried out or is carried out. For this purpose, the low-pressure exhaust gas recirculation device 38, which is also simply referred to as the exhaust gas recirculation device, comprises a recirculation line 40, also referred to as the exhaust gas recirculation line. By means of the recirculation line 40, at least a portion of the exhaust gas flowing through the exhaust tract 24 can be diverted from the exhaust tract 24 at a branch point A located downstream of the turbine wheel 30 and introduced into the recirculation line 40. The exhaust gas diverted from the exhaust tract 24 at the branch point A flows into the return line 40 and flows through the return line 40 and is returned to the intake tract 18 by means of the return line 40 and introduced into the intake tract 18 at an inlet point E.The low-pressure exhaust gas recirculation device 38 includes an exhaust gas recirculation cooler 42, also referred to as an EGR cooler, which is arranged in the recirculation line 40 and through which the recirculated exhaust gas flows. The exhaust gas is cooled by means of the exhaust gas recirculation cooler 42.

[0024] In order to achieve particularly large exhaust gas recirculation rates, i.e., particularly large quantities of exhaust gas to be recirculated, in a particularly simple, especially cost-effective and space-saving manner, the low-pressure exhaust gas recirculation device 38 features Fig. 1. A valve element 44, arranged in the return line 40 and designed as a check valve, is provided. The check valve prevents the exhaust gas from flowing through the return line 40 in a first flow direction, and the check valve allows the exhaust gas to flow through the return line 40 in a second flow direction opposite to the first flow direction. It is preferably provided that the exhaust gas flows through the return line 40 in the second flow direction on its way from the branch point A to the inlet point E, i.e., it can be directed or is directed through the return line 40 in the second flow direction from the branch point A to the inlet point E. Thus, it is preferably provided that the check valve opens in the direction of the inlet point E and closes in the direction of the branch point A, in particular automatically.This allows the exhaust gas to flow through the return line 40 in the second flow direction and thus flow from the branch point A to the inlet point E, however the check valve prevents an opposite flow of the exhaust gas from the inlet point E to or in the direction of the branch point A.

[0025] The check valve has a valve part 46 that is movable, in particular translationally, relative to the return line 40. The valve part 46 is movable relative to the return line 40, in particular exclusively or at least translationally, between a closed position and at least one open position. The valve part 46 is, for example, movable in the second flow direction from the closed position to the open position and in the first flow direction from the open position to the closed position, such that the valve part 46 allows the exhaust gas to flow through the return line 40 from the branch point A to the inlet point E, but prevents the exhaust gas from flowing in the opposite direction from the inlet point E to the branch point A.For example, the valve part 46 can be moved from the closed position to the open position, particularly exclusively, by a flow of exhaust gas in the second flow direction through the return line 40. In the open position, for example, a [missing information] is present. Fig. 1. A spring element (not shown), in particular a mechanical spring element, which functions as a return spring, is tensioned, thereby providing a spring force. By means of this spring force, the valve part 46 can be moved from the open position to the closed position and, in particular, held in the closed position, so that the check valve can be opened by a flow of exhaust gas in the second flow direction in the return line 40, i.e., is opened, and closes automatically. In particular, the valve part 46 can be moved from the closed position to the open position by means of a flow of exhaust gas in the direction of the inlet point E, against the spring force.

[0026] In the direction of flow of the exhaust gas flowing through the return line 40 and thereby flowing from the branch point A towards the inlet point E, the following occurs in the Fig. In the internal combustion engine shown in Figure 1, the valve element 44 is arranged downstream of the exhaust gas recirculation cooler 42. The low-pressure exhaust gas recirculation system 38 includes an additional exhaust gas recirculation valve 48, which is arranged downstream of the exhaust gas recirculation cooler 42 and preferably also downstream of the valve element 44, in the flow direction of the exhaust gas flowing through the recirculation line 40 from the branch point A to the inlet point E. For example, the exhaust gas recirculation valve 48 has an adjustable, i.e., variable, flow cross-section through which the recirculated exhaust gas flows, which is also simply referred to as the cross-section. By adjusting, i.e., by changing the flow cross-section, the exhaust gas recirculation rate can be set, i.e., varied.In particular, the exhaust gas recirculation valve 48 is electrically controllable, i.e., electrically operable and thus electrically controllable, so that by electrically controlling the exhaust gas recirculation valve 48 and thus using electrical energy the flow cross-section and thus the exhaust gas recirculation rate can be adjusted.

[0027] Fig. Figure 2 shows a schematic perspective view of the exhaust gas recirculation cooler 42 for an embodiment of the internal combustion engine 10 according to the invention. Fig. 2 it can be seen that the exhaust gas recirculation cooler 42 has several cooling channels 50, which can be flowed through by the recirculated exhaust gas and are simply referred to as channels, and which are fluidically separated from each other, for example in the exhaust gas recirculation cooler 42.

[0028] Fig. Figure 3 shows the exhaust gas recirculation cooler 42 according to Fig. 2 in a schematic sectional view along a Fig. 2. Section line labeled AA. From Fig. Figure 3 shows that a valve element 44 is arranged in each channel 50, which in the embodiment according to the invention is designed as a Testla valve. Furthermore, Figure 3 illustrates that... Fig.Arrows 52 represent the second flow direction, while arrow 54 illustrates the first flow direction. In other words, arrows 52 illustrate the exhaust gas flowing through the return line 40 from branch point A to inlet point E, so that arrow 54 illustrates the flow of exhaust gas through the return line 40 from inlet point E towards branch point A. The respective Tesla valve exhibits a first flow resistance for the exhaust gas flowing towards inlet point E in the return line 40 and a second flow resistance, which is greater than the first, for the exhaust gas flowing towards branch point A in the return line 40.In other words, the Tesla valve exhibits a first flow resistance for the exhaust gas flowing through it towards the inlet point E, and a second flow resistance for the exhaust gas flowing through it towards the branch point A, which is significantly greater than the first flow resistance. This at least limits the backflow of exhaust gas towards branch point A in the valve element 44 and thus in the return line 40. In other words, the valve element 44 prevents excessive backflow of exhaust gas in the return line 40 towards branch point A. The Tesla valve is characterized by being a passive valve without moving parts to influence the exhaust gas flowing through it.For example, the Tesla valve has ribs 56, each rib extending from a wall region 58 of the exhaust gas recirculation cooler 42, which directly borders the respective channel 50, into the respective channel 50 and thus projecting into the respective channel 50. The rib 56, viewed from the wall region 58 into the channel 50, is inclined in the second flow direction, which is desired or preferred compared to the first flow direction, and thus runs obliquely to the flow directions. The respective rib 56 is not movable relative to the wall region 58, but is fixed to the wall region 58, so that the Tesla valve is free of moving components that could influence the exhaust gas flowing through the Tesla valve or its flow.Since in the embodiment according to the invention the valve element 44 is arranged in the exhaust gas recirculation cooler 42, the valve element 44 is integrated into the exhaust gas recirculation cooler 42, which allows the installation space requirement of the low-pressure exhaust gas recirculation device 38 to be kept within a particularly small range.

[0029] In turbocharged internal combustion engines, such as the internal combustion engine 10, which is designed in particular as a gasoline engine and has low-pressure exhaust gas recirculation, a pressure difference between the branch point A, also referred to as the extraction point, and the inlet point E, also referred to as the injection point, may not be sufficient in certain operating ranges to achieve a desired high exhaust gas recirculation rate, especially at rather low engine speeds and medium load of the internal combustion engine 10.By means of the valve element 44 arranged in the return line 40 of the low-pressure exhaust gas recirculation device 38, pressure fluctuations of the exhaust gas in the exhaust tract 24 at the branch point A, referred to as exhaust gas pulsations or pulsations, can now also be used to prevent a back-and-forth flow of the exhaust gas in the return line 40 and, on the contrary, to pump the exhaust gas through the return line 40 in the direction of or to the inlet point E. In this way, large flows or quantities of exhaust gas can be achieved in the direction of the inlet point E in a particularly simple manner.

[0030] It is conceivable that several valve elements 44, in particular several Tesla valves, can be arranged in the return line 40, wherein, for example, the valve elements 44 are connected in series or parallel to each other in terms of flow characteristics. In particular, the valve elements 44 arranged in the exhaust gas recirculation cooler 42 are connected in parallel to each other in terms of flow characteristics in the second embodiment, i.e., arranged parallel to each other. The Tesla valve is characterized by the fact that it does not require the use of moving or movable parts and is therefore particularly cost-effective, space-saving, and less prone to failure. Damage can be almost completely ruled out, and the Tesla valve can be constructed using simple and inexpensive means.The Tesla valve may not completely prevent the backflow of exhaust gas in the return line 40, but rather only minimizes, thus hindering or limiting, such backflow. However, the Tesla valve only slightly impedes the flow of exhaust gas in the desired, secondary direction, and thus towards the inlet point E. This is sufficient to achieve the desired effect and high exhaust gas recirculation rates. Even with particularly high exhaust gas flows, the flow is not excessively impeded, but sufficiently so that controlling the exhaust gas recirculation valve 48 becomes particularly easy. Due to the consistently sufficient flow of the recirculated exhaust gas, the exhaust gas recirculation valve 48 can also be advantageously dimensioned small.

[0031] The channels 50 are particularly well-suited for being fitted with rib- or paddle-shaped obstructions, thus enabling their use as the valve element 44, specifically as the Tesla valve. The ideal channel is therefore designed such that the exhaust gas flow towards the inlet point E follows a relatively straight path, whereas the obstructions in the opposite direction, i.e., in the first flow direction, cause strong turbulence and thus disrupt the exhaust gas flow. The ribs also increase the surface area available for heat transfer and therefore improve the cooling effect of the exhaust gas recirculation cooler. Reference symbol list 10 Internal combustion engine 12 Motor housings 14 cylinders 16 Combustion chamber 18 Intake tract 20 charge air distributors 22 air filters 24 Exhaust system 26 exhaust gas turbochargers 28 compressor wheel 30 turbine wheel 32 wave 34 Intercoolers 36 Exhaust aftertreatment system 38 Low-pressure exhaust gas recirculation device 40 Return line 42 Exhaust gas recirculation coolers 44 Valve element 46 Valve part 48 Exhaust gas recirculation valve 50-channel 52 Arrow 54 Arrow 56th rib 58 wall area A junction E Induction point

Claims

[1] Internal combustion engine (10) for a motor vehicle, comprising an intake manifold (18) through which air flows, by means of which the air flowing through the intake manifold (18) is to be guided into at least one combustion chamber (16) of the internal combustion engine (10), an exhaust manifold (24) through which exhaust gas flows from the combustion chamber (16), an exhaust gas turbocharger (26) which has a turbine wheel (30) arranged in the exhaust manifold (24) and driven by the exhaust gas and a compressor wheel (28) arranged in the intake manifold (18) and driven by the turbine wheel (30) for compressing the air, and a low-pressure exhaust gas recirculation device (38) which has at least one recirculation line (40) by means of which at least a part of the exhaust gas flowing through the exhaust manifold (24) can be diverted from the exhaust manifold (24) at a branch point (A) arranged downstream of the turbine wheel (30),is retractable to the intake tract (18) and can be introduced into the intake tract (18) at an inlet point (E), , characterized by , that at least one valve element (44) is arranged in the return line (40) which is designed as a Tesla valve, wherein the low-pressure exhaust gas recirculation device (38) has an exhaust gas recirculation cooler (42) arranged in the return line (40) for cooling the exhaust gas to be recirculated, and wherein the exhaust gas recirculation cooler (42) has several cooling channels (50) through which the exhaust gas to be recirculated can flow, wherein a respective valve element (44) which is designed as a Tesla valve is arranged in the respective channel (50). [2] Internal combustion engine (10) according to claim 1, characterized by, that the valve element (44) designed as a Tesla valve has a first flow resistance for the exhaust gas flowing in the return line (40) towards the inlet point (E) and a second flow resistance that is greater than the first flow resistance for the exhaust gas flowing in the return line (40) towards the branch point (A). [3] Internal combustion engine (10) according to claim 1 or 2, characterized by , that the low-pressure exhaust gas recirculation device (38) has an exhaust gas recirculation valve (48) arranged in the recirculation line (40) and provided in addition to the valve element (44), by means of which a quantity of the exhaust gas to be recirculated can be adjusted. [4] Internal combustion engine (10) according to claim 3, characterized by , that the exhaust gas recirculation valve (48) is arranged downstream of the valve element (44) in the direction of flow of the exhaust gas flowing towards the inlet point (E). [5] Internal combustion engine (10) according to claim 3 or 4, characterized by , that the exhaust gas recirculation valve (48) is arranged downstream of the exhaust gas recirculation cooler (42) in the direction of flow of the exhaust gas flowing towards the inlet point (E). [6] Internal combustion engine (10) according to any one of the preceding claims, characterized by , that the inlet point (E) is arranged upstream of the compressor wheel (28) in the direction of flow of the air flowing through the intake tract (18) and towards the combustion chamber (16). [7] Motor vehicle, comprising an internal combustion engine (10) according to any of the preceding claims.

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