Internal combustion engine for a motor vehicle, in particular for a motor vehicle

Abstract

Internal combustion engine (12) for a motor vehicle, with an exhaust tract (20) through which exhaust gas from the internal combustion engine (12) can flow, and with a secondary air system (22) which has: - a secondary air line (24) through which air can flow as secondary air in an injection direction (26), whereby the secondary air flowing through the secondary air line (24) in the injection direction (26) can be introduced into the exhaust tract (20), and - at least one valve element (10) arranged in the secondary air line (24), which has a first flow resistance along the injection direction (26) and a second flow resistance that is greater than the first flow resistance along a return flow direction (28) opposite to the injection direction (26), whereby a return flow occurring in the return flow direction (28) can be at least limited, characterized in that the valve element (10) has a plurality of rotationally symmetrical impact bodies (30) arranged one after the other along the injection direction (26), which are connected to one another, and is arranged in a length region (L) of the secondary air line (24), the length region (L) of which is delimited by a component (14) of the internal combustion engine (12) that is formed separately from the valve element (10), wherein the respective impact body (30) has a respective,has a region (B1) that continuously widens along the blowing direction (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.

[0002] DE 10 2019 217 473 A1 discloses an internal combustion engine with a primary air system for providing fresh air. A secondary air system is also provided, which is configured to divert secondary air from the primary air system and inject it into an exhaust duct. A line is known from US Pat. No. 1,329,559 A. Furthermore, DE 10 2018 107 436 A1 discloses an internal combustion engine with an exhaust gas recirculation system and a recirculation valve for controlling the amount of exhaust gas to be recirculated into the fresh air duct. Furthermore, DE 10 2018 106 679 A1 discloses a method for operating an internal combustion engine.

[0003] DE 330 151 A discloses at least one valve element for influencing a flow resistance, which can be inserted into a line.

[0004] JP S 60 - 32 516 U and US 2019 / 0 101 230 A1 each disclose at least one valve element for influencing a flow resistance in a line.

[0005] The object of the present invention is to provide an internal combustion engine for a motor vehicle so that a particularly advantageous secondary air injection can be realized.

[0006] This object is achieved by an internal combustion engine having the features of patent claim 1. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0007] The invention relates to an internal combustion engine, also referred to as a motor or internal combustion engine and designed, for example, as a reciprocating piston engine, for a motor vehicle, in particular for a car and most particularly for a passenger car. This means that the motor vehicle, 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 exhaust tract through which exhaust gas from the internal combustion engine flows. For example, when the internal combustion engine is fired, combustion processes take place in the internal combustion engine, in particular in the combustion chambers of the internal combustion engine. During each combustion process, a fuel-air mixture, also simply referred to as a mixture, is burned, resulting in the exhaust gas.The exhaust gas can flow out of the respective combustion chamber, flow into the exhaust tract, and flow through the exhaust tract. The internal combustion engine also has a secondary air system, by means of which, as will be explained in more detail below, secondary air injection can be carried out. The secondary air system has a secondary air line through which air can flow as secondary air in an injection direction, whereby the secondary air flowing through the secondary air line in the injection direction can be introduced into the exhaust tract. In other words, secondary air injection comprises the secondary air flowing through the secondary air line in the injection direction and thus being introduced into the exhaust tract by means of the secondary air line, which is also referred to as injection of the secondary air. The secondary air flowing through the secondary air line in the injection direction thus flows in the direction of the exhaust tract or towards the exhaust tract.In particular, the secondary air is introduced, i.e. blown in, into the exhaust tract by means of the secondary air line, bypassing the combustion chambers or preferably all of the combustion chambers of the internal combustion engine. This means that the secondary air does not enter the exhaust tract via one of the combustion chambers, but rather the secondary air does not flow through the combustion chambers of the internal combustion engine on its way through the secondary air line into the exhaust tract, and thus the secondary air bypasses the combustion chambers or all of the combustion chambers of the internal combustion engine. In other words, the secondary air is introduced, i.e. blown in, directly into the exhaust tract by means of the secondary air line. In particular, the secondary air flowing through the secondary air line in the injection direction can be introduced, in particular directly, into the exhaust tract at at least one or exactly one inlet point by means of the secondary air line.In this case, the inlet point is arranged in particular downstream of the or all combustion chambers of the internal combustion engine, and for example the inlet point is arranged in a cylinder head of the internal combustion engine.

[0008] For example, at least one exhaust gas aftertreatment element for aftertreating the exhaust gas is arranged in the exhaust tract, in particular downstream of the inlet point. The exhaust gas aftertreatment element is, for example, or comprises a catalytic converter. The secondary air introduced into the exhaust tract, i.e. introduced, is used in particular to heat up, i.e., to warm the exhaust gas aftertreatment element. For this purpose, for example, a fuel, i.e., unburned hydrocarbons in the exhaust tract can react with oxygen originating from the secondary air, whereby the fuel is combusted, in particular with the release of heat. The released heat can be used to heat the exhaust gas aftertreatment element effectively and, in particular, particularly quickly.

[0009] The secondary air originates, for example, from an intake tract of the internal combustion engine, also referred to as the intake tract. Air, which is also referred to as fresh air, can flow through the intake tract. The fresh air is guided to and into the combustion chambers via the intake tract. In this case, at least part of the fresh air flowing through the intake tract can be branched off from the intake tract and fed into the secondary air duct, for example, in particular by means of the secondary air duct. The part of the fresh air fed into the secondary air can flow through the secondary air duct as the aforementioned secondary air and is subsequently fed into the exhaust duct, in particular directly, via the secondary air duct. In particular, the secondary air system can have an air pump, also simply referred to as a pump, by means of which the secondary air can be conveyed through the secondary air duct.

[0010] The secondary air system also has at least one valve element arranged in the secondary air line and thus through which the secondary air can flow, in particular in the injection direction, and which has a first flow resistance along the injection direction, in particular for a gas such as the secondary air. Along a return flow direction opposite to the injection direction, the valve element has a second flow resistance, in particular for the gas, which is, in particular significantly, greater than the first flow resistance. As a result, the valve element can at least limit, in particular prevent, backflow in the return flow direction, in particular of the gas. The valve element is thus a backflow limiter or a backflow preventer, since the valve element prevents, in particular, undesirable backflow, for example of the gas, through or in the secondary air line.

[0011] As previously mentioned, the gas mentioned can be the secondary air. Thus, for example, the valve element provides the first flow resistance for the secondary air along the injection direction and the second flow resistance along the return flow direction. Furthermore, the gas can be the exhaust gas. In other words, assuming the exhaust gas were to be passed or flow through the secondary air line in the injection direction, the valve element would have or provide the first flow resistance for the exhaust gas flowing through the secondary air line in the injection direction. Along the return flow direction, however, the valve element has the second flow resistance which is greater than the first flow resistance.This secondary air and the exhaust gas are to be regarded as very similar or identical in terms of their flow behavior and in particular in terms of the flow resistance of the valve element, so that the valve element, on the one hand, allows the secondary air to flow through the secondary air line and thus the valve element in the injection direction and is thus introduced, in particular directly, into the exhaust tract. On the other hand, the valve element prevents or prevents an excessive flow of exhaust gas through the valve element and thus through the secondary air line in the return flow direction opposite to the injection direction. The valve element thus prevents an excessive amount of exhaust gas from the exhaust tract from flowing into the secondary air line and / or an excessively far penetration of the exhaust gas from the exhaust tract into the secondary air line.For example, for this purpose the valve element is designed such that when the gas such as the secondary air and the exhaust gas flows or would flow through the valve element in the injection direction, the valve element generates a first pressure loss of the gas or its flow. Furthermore the valve element is designed such that when the gas such as the secondary air or the exhaust gas flows or would flow through the valve element in the return flow direction or is or would be passed through, in particular actively and thus for example under force, the valve element generates a second pressure loss of the gas or its flow, wherein the second pressure loss is, in particular significantly, greater than the first pressure loss.

[0012] This prevents excessive inflow or backflow of exhaust gas into or into the secondary air line.

[0013] In order to be able to introduce, i.e. introduce or blow in, the secondary air in a particularly advantageous manner by means of the secondary air line and thus via the valve element into the exhaust tract, the invention provides that the valve element has a plurality of impact bodies arranged one after the other along or in the injection direction and thus one behind the other, wherein the respective impact body is designed to be rotationally symmetrical in itself, i.e. viewed on its own. On its way through the secondary air line and through the valve element towards the exhaust tract, the secondary air first flows past and around a first of the impact bodies, whereupon the secondary air flows past and around a second of the impact bodies. The second impact body is arranged downstream of the first impact body, viewed in the injection direction, i.e. along the injection direction.The impact bodies are connected to one another, forming an assembled unit in itself, i.e., viewed individually. In its assembled state, the unit can be handled as a whole, for example, by a person or a robot, and thus, for example, assembled, i.e., installed. In particular, the assembly can be the valve element.

[0014] The valve element and thus the structural unit are arranged in a longitudinal region of the secondary air line, wherein the longitudinal region is delimited by a component of the internal combustion engine that is formed separately from the valve element and thus separately from the structural unit. The invention makes it possible, for example during production of the internal combustion engine, to handle the structural unit and thus the plurality of impact bodies and / or a group and / or of impact bodies simultaneously and thus, for example, to move and install them relative to the component, for example by moving the structural unit into the longitudinal region and thus arranging it in the longitudinal region.

[0015] Each impact body has a respective area that continuously expands along the injection direction, i.e., viewed in the injection direction. This advantageously allows the first flow resistance to be kept low. At the same time, the second flow resistance can be advantageously designed to be large. This allows, on the one hand, the valve element to be designed particularly compactly, so that the valve element and thus the secondary air line and also the inlet point can be positioned particularly advantageously. On the other hand, an undesired flow of exhaust gas into and / or within the secondary air line can be avoided.

[0016] In principle, it is conceivable for the impact bodies to be formed separately from one another and connected to one another. However, it has proven particularly advantageous for the impact bodies to be formed integrally with one another. This means that the impact bodies are integral components of a one-piece body, i.e., one-piece and thus integrally manufactured. The body is not composed of several separately formed components, but rather the body is formed as a single block through which the impact bodies are formed.

[0017] Furthermore, it is preferably provided that the valve element is designed as a passive valve element without moving parts, whereby an excessive, undesirable backflow, in particular of the exhaust gas, into or in the secondary air line can be avoided.

[0018] In order to be able to introduce, in particular blow, the secondary air into the exhaust tract in a particularly advantageous manner, an advantageous embodiment of the invention provides that the component is the aforementioned cylinder head of the internal combustion engine. For example, the respective combustion chamber is partially delimited by a respective combustion chamber roof, wherein the respective combustion chamber roof is formed by the cylinder head.

[0019] Preferably, the length range is directly delimited by the component, in particular by an inner peripheral and thus in particular concave lateral surface of the component, wherein, for example, the valve element, in particular an outer peripheral and thus for example convex lateral surface of the valve element, directly touches the component, in particular the inner peripheral lateral surface.

[0020] A further embodiment is characterized in that at least one part of the component that directly defines the longitudinal region is formed in one piece. This particularly means that at least the part of the component is manufactured integrally and thus in one piece and thus formed as a monoblock, so that the part of the component is not composed of several components that are formed separately from one another and formed together. This allows the secondary air to be introduced into the exhaust tract particularly easily and, in particular, particularly cost-effectively.

[0021] In order to be able to realize a particularly advantageous and in particular cost-effective as well as effective and efficient secondary air injection, it is provided in a further embodiment of the invention that at least part of the component is produced by casting and is thus designed as a cast component.

[0022] The valve element thus functions as a check valve or a type of non-return valve, but preferably without moving components. This allows for a particularly compact design of the valve element, allowing the valve element and, consequently, the secondary air line and, in particular, the inlet point to be positioned advantageously. This allows for particularly advantageous secondary air injection.

[0023] In order to be able to realize the respective flow resistance particularly advantageously, it is provided in a further embodiment of the invention that the respective region which continuously widens along the injection direction is conical or frustoconical.

[0024] The respective area that continuously expands along the blowing direction is also called the first area.

[0025] A further embodiment provides that, along the injection direction, i.e., viewed in the injection direction, the respective first region of the respective impact body is followed by a respective second region of the respective impact body. The respective second region of the respective impact body tapers continuously along the injection direction, i.e., in the injection direction. This allows the flow resistances to be configured particularly advantageously, while simultaneously allowing a particularly compact design of the valve element to be achieved.

[0026] It has proven particularly advantageous if the respective second region is conical or truncated cone-shaped. This ensures, on the one hand, a particularly advantageous flow of the secondary air in the injection direction and thus toward the exhaust tract. On the other hand, an undesirable backflow of the exhaust gas in the secondary air line can be advantageously avoided.

[0027] In order to be able to guide the secondary air particularly well in the blow-in direction through the secondary air line on the one hand, but to be able to avoid excessive backflow of the exhaust gas on the other hand, while at the same time realizing a compact design of the valve element, it is provided in a further embodiment of the invention that the largest outer circumference, in particular the largest outer diameter, of the respective first region is larger than the largest or maximum outer circumference, in particular outer diameter, of the respective second region.

[0028] Furthermore, it is conceivable for the respective second region to transition into the respective first region via a respective transition region, wherein the respective transition region is preferably curved in the return flow direction and thus counter to the injection direction. In particular, the transition region is an annular region which extends in the circumferential direction of the respective impact body, in particular completely circumferentially, around the respective second region. This advantageously prevents excessive backflow of exhaust gas in the secondary air line.

[0029] Finally, it has proven particularly advantageous if a respective ring of the valve element is assigned to the respective impact body, wherein the respective impact body engages in the ring assigned to the respective impact body. The rings are connected to one another and to the impact bodies, so that the rings are preferably components of the structural unit. It is conceivable that the rings are formed integrally with one another, so that the rings are preferably integral components of an annular body. In particular, it is conceivable that the rings and thus the annular body are formed integrally with the aforementioned body, thus integrally with the impact bodies.Thus, both the rings and the impact bodies are preferably integral components of the aforementioned monoblock body, which is manufactured integrally and thus in one piece, rather than composed of multiple, separately formed and interconnected components. This allows for a particularly compact design of the valve element, allowing, in particular, the inlet point to be advantageously positioned. Consequently, a particularly advantageous secondary air injection can be achieved.

[0030] For example, the internal combustion engine is a gasoline engine. In particular, the internal combustion engine can be a supercharged internal combustion engine. This particularly means that the internal combustion engine has at least one exhaust gas turbocharger, which has a compressor arranged in the intake tract and a turbine arranged in the exhaust tract. The turbine is driven by the exhaust gas, and the compressor is driven by the turbine. By driving the compressor, the fresh air flowing through the intake tract can be compressed by means of the compressor.

[0031] The invention is based in particular on the following findings and considerations. The secondary air injection serves, in particular in a gasoline engine charged by an exhaust gas turbocharger, to bring the temperature of the exhaust gas aftertreatment element particularly quickly to an advantageous operating temperature, for example after a cold start of the internal combustion engine, in particular by means of post-reaction of the exhaust gas or of components contained in the exhaust gas, and thus to avoid excessive emission of undesirable components. In particular, the components mentioned can be the fuel, i.e. unburned hydrocarbons. For example, at least one respective exhaust port is assigned to the respective combustion chamber, which is arranged in particular in the said cylinder head. In particular, the respective exhaust port is delimited, in particular directly, by the cylinder head.At least one or more exhaust valves are assigned to the respective combustion chamber, which are movable relative to the cylinder head, in particular translationally. The respective exhaust gas can flow out of the respective combustion chamber via the respective exhaust valve and into the respective exhaust port. The exhaust port is also referred to as the exhaust duct.

[0032] It has proven particularly effective if the secondary air is blown into the respective exhaust duct, in particular into each individual exhaust duct, immediately after the respective exhaust valve or after the respective exhaust valves. In particular, the respective exhaust duct or exhaust duct is a component of the exhaust system. An operating strategy of the internal combustion engine can provide for high loads and thus high mean effective pressures at low engine speeds, even in an operating phase in which secondary air is blown into the exhaust system, in order to enable operation with the lowest possible fuel consumption. In particular, the respective exhaust duct is a component of the exhaust system. However, this can lead to the problem that exhaust gas back pressure and, in particular, exhaust surges of the exhaust gas can make it very difficult to blow sufficient amounts of secondary air into the respective exhaust duct and thus into the exhaust system.If, for example, the pressure of the secondary air, particularly that caused by the air pump, also referred to as the secondary air pump, is not sufficient, then with each exhaust gas burst there will be such a large backflow of exhaust gas into the secondary air line and thus into a secondary air duct delimited by the secondary air line, in particular directly, that an average flow of secondary air is no longer sufficient for a sufficient reaction in the exhaust tract and thus for a sufficient heating of the exhaust gas aftertreatment element, unless appropriate countermeasures are taken.

[0033] One possible solution to the problem is to equip the secondary air pump with a particularly high output, thus using a particularly powerful secondary air pump. For example, the secondary air pump could be an electric secondary air pump, meaning it can be operated electrically. However, this has the disadvantage that the power consumption of the secondary air pump is then very high, which leads to additional strain on the vehicle's electrical system. In addition, the secondary air line and a secondary air valve, which is arranged, for example, in the secondary air line and designed to adjust the amount of secondary air to be introduced into the exhaust tract, must withstand the higher pressure of the secondary air, which makes the secondary air line and the secondary air valve more space-, weight-, and cost-intensive.In particular, the secondary air valve is arranged upstream of the valve element along the injection direction.

[0034] It has been found that check valves in secondary air lines or manifolds running outside the cylinder head cannot adequately prevent the backflow of exhaust gas, particularly into the injection channels of the individual combustion chambers. Due to the compressibility of the secondary air, even long channels allow the undesired penetration of exhaust gas into the secondary air line. It is therefore advantageous to arrange a backflow preventer or limiter, such as the valve element, particularly close to the respective exhaust valve or valves. It is particularly conceivable that the respective combustion chamber or each combustion chamber is assigned at least one or exactly one respective inlet point at which the secondary air can be introduced into the exhaust tract.It is particularly advantageous if the valve element, designed for example as a backflow preventer or backflow limiter, is arranged particularly close to the respective exhaust valve. It is therefore advantageous to arrange the valve element in the cylinder head. However, the installation space in the cylinder head is usually very limited, so that the valve element should be particularly compact. This can now be realized by the invention. The valve element of the internal combustion engine according to the invention thus represents a countermeasure to prevent excessive backflow of exhaust gas into or in the secondary air line. Since a particularly compact design of the valve element can be realized by the invention, the valve element can be arranged particularly close to or after the respective exhaust valve and thus in the cylinder head.In particular, a particularly large number of impact bodies can be realized, so that excessive backflow can be particularly well avoided.

[0035] Conventional ball check valves are unsuitable for preventing or limiting unwanted backflow in or within the secondary air line due to their excessive inertia. Even tongue or flap valves, as well as plate valves, are unsuitable for use in the secondary air line, as they could lead to service life problems. They are also exposed to contamination by soot particles from combustion if the exhaust gas enters the secondary air duct or line, at least briefly.

[0036] Compared to conventional solutions, the invention enables a particularly compact design of the valve element, allowing the valve element to be positioned particularly close to the respective exhaust valve of the respective combustion chamber, particularly in the cylinder head. This allows for advantageous secondary air injection. Furthermore, excessive backflow of exhaust gas into and / or within the secondary air line can be avoided.

[0037] In particular, the valve element of the internal combustion engine according to the invention can be a Tesla valve or designed in the manner of a Tesla valve. In particular, it is conceivable for the respective ring to be rotationally symmetrical, in particular with respect to the same axis with respect to which the respective impact body is also rotationally symmetrical. Due to its compactness, the valve element of the internal combustion engine according to the invention can be used in a secondary air intake that is only slightly larger than conventional solutions and, for example, is designed as a bore, which, for example, is within the aforementioned length range.

[0038] In particular, due to the compactness of the valve element and the rotationally symmetrical design of the impact bodies, it is possible to position the valve element very close to the exhaust port or the exhaust valve. The volume of secondary air between the respective exhaust valve and the exhaust port is therefore very small. Nevertheless, a large number of impact bodies can be realized.

[0039] For example, the respective impact body and the respective ring assigned to the respective impact body form a ring-impact body pair, whereby a particularly high number of ring-impact body pairs can be represented. This makes it possible to achieve a particularly high blocking effect, so that excessive backflow of the exhaust gas into and / or in the secondary air line can be avoided. Therefore, in the event of an exhaust surge, only a small amount of the exhaust gas can enter the secondary air line and thus be lost to a surge unloading effect of the exhaust gas turbocharger or turbine. In addition, a large mass flow of secondary air can be easily injected into the exhaust tract without the need for a complex, costly and weight-intensive secondary air pump.This improves the heating effect of the exhaust aftertreatment element compared to conventional solutions, and the time required to reach a significant conversion rate of the exhaust aftertreatment element can be shortened. This enables particularly low-emission operation of the internal combustion engine. Furthermore, exhaust gas hardly penetrates the secondary air line, preventing excessive contamination and soot deposits in the secondary air line, which could clog the cross-sections of the secondary air line over extended periods of operation.

[0040] The secondary air system preferably has the aforementioned secondary air valve, by means of which, for example, the secondary air line can be switched off, in particular completely, i.e. fluidically blocked. In particular, the secondary air valve makes it possible to switch off the secondary air injection, in particular by means of the secondary air valve, in particular completely, fluidically blocking the secondary air line, since the secondary air injection is not required for large parts of the operation of the internal combustion engine. By completely, fluidically blocking the secondary air line by means of the secondary air valve, in particular, backflow of the exhaust gas and thus escape of the exhaust gas via the secondary air system can be prevented, in particular at high loads. In particular, the secondary air valve is a switching valve.Viewed along the injection direction, the secondary air valve is arranged upstream of the valve element and, in particular, in the secondary air line. Since the valve element of the internal combustion engine according to the invention has a particularly advantageous blocking effect, thus preventing excessive backflow of exhaust gas into and in the secondary air line, the secondary air valve can be particularly advantageously protected against contamination and thus against malfunctions and premature failure by means of the valve element.

[0041] 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 figures, 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.

[0042] The drawing shows: Fig. 1 is a schematic side view of a valve element of a secondary air system for an internal combustion engine of a motor vehicle; and Fig. 2 is a schematic longitudinal sectional view of the valve element along a Fig. 1 section line marked AA; Fig. 3 a schematic plan view of the valve element; and Fig. 4 is a schematic longitudinal sectional view of the valve element according to a Fig. 3 cutting line marked BB; Fig. 5 shows a partial schematic sectional view of the internal combustion engine equipped with the secondary air system and the valve element; and Fig. 6 shows a further schematic sectional view of the internal combustion engine.

[0043] In the figures, identical or functionally identical elements are provided with the same reference symbols.

[0044] Fig. 1 shows a schematic side view of a valve element 10 of a secondary air system of an internal combustion engine for a motor vehicle. The internal combustion engine is in Fig. 5 and Fig. 6 is shown in detail in a respective schematic sectional view and designated by 12. The internal combustion engine 12 has an exhaust tract through which exhaust gas from the internal combustion engine 12 can flow, and the secondary air system. In particular, the internal combustion engine 12 has a plurality of combustion chambers. The respective combustion chamber is, for example, partially delimited by a respective cylinder of the internal combustion engine 12. For example, the respective cylinder is delimited by an engine housing of the internal combustion engine 12. The engine housing is, for example, a cylinder housing, in particular a cylinder crankcase. The internal combustion engine 12 is designed as a reciprocating piston engine.A respective piston is accommodated in the respective cylinder for translational movement, so that the respective combustion chamber is partially delimited by the respective cylinder and partially by the respective piston accommodated in the respective cylinder for translational movement. Furthermore, the respective combustion chamber is partially delimited by a respective combustion chamber roof. The respective combustion chamber roof is formed by a cylinder head 14 of the internal combustion engine 12. The cylinder head 14 is formed separately from the engine housing and connected to the engine housing. From . Fig. 5 shows that at least one exhaust valve 16 and at least one exhaust port 18 are assigned to the respective combustion chamber. In particular, at least or exactly two exhaust valves 16 are assigned to the respective combustion chamber. During fired operation of the internal combustion engine 12, combustion processes take place in the respective combustion chamber. During the respective combustion process, a fuel-air mixture, also simply referred to as a mixture, is burned. This results in the aforementioned exhaust gas. The exhaust gas can flow out of the respective combustion chamber and, via the respective exhaust valve 16 assigned to the respective combustion chamber, flow into the respective exhaust port 18 assigned to the respective combustion chamber and subsequently flow through the respective exhaust port 18, which is also referred to as an exhaust port or exhaust line.The respective exhaust port 18 is a component of the aforementioned exhaust tract of the internal combustion engine 12, whose exhaust tract is designated by 20. It can be seen that the respective exhaust port 18 is arranged in the cylinder head 14. The respective exhaust port 18 is formed, in particular directly, by the cylinder head 14, i.e., is delimited.

[0045] The Fig. 5 and Fig. The secondary air system of the internal combustion engine 12, which can be seen in detail in Figure 6 and is designated by 22 there, has, in particular per combustion chamber, at least or exactly one secondary air line 24, which supplies air as secondary air into a Fig. 5 by an arrow 26. As a result, the secondary air flowing through the secondary air line 24 in the injection direction (arrow 26) can be introduced into the outlet channel 18 and thus into the exhaust tract 20. In the exhaust tract 20, downstream of the outlet channel 18, at least a first exhaust gas aftertreatment element for aftertreating the exhaust gas is arranged. For example, the exhaust gas aftertreatment element comprises a catalyst. By means of the secondary air, the catalyst can be heated particularly quickly and thus brought to its operating temperature. The introduction of the secondary air into the exhaust tract 20 is also referred to as blowing in the secondary air or as secondary air injection. Fig. 5 it can be seen that the secondary air flowing through the secondary air line 24 in the injection direction can flow out of the secondary air line 24 at an inlet point E and into the outlet channel 18 and thus into the exhaust tract 20. In particular, the secondary air line 24 opens into the outlet channel 18 at the inlet point E and thus into the exhaust tract 20. A return flow direction opposite to the injection direction is shown in Fig. 5 is illustrated by an arrow 28.

[0046] The secondary air system 22 also has, in particular for each secondary air line 24, a valve arranged in the secondary air line 24, which Fig. 1. The valve element 10 has a first flow resistance along the injection direction, in particular for a gas flowing through the secondary air line 24 in the injection direction. Along the return flow direction opposite to the injection direction, the valve element 10 has a second flow resistance, in particular for the gas flowing through the secondary air line 24 in the return flow direction, which second flow resistance is, in particular significantly, greater than the first flow resistance. The gas can be understood, for example, as both the secondary air and the exhaust gas. If, for example, the secondary air flows in the injection direction through the secondary air line 24 and thus through the valve element 10, the valve element 10 has the first flow resistance for the secondary air.If, for example, the secondary air were to flow in the return flow direction through the secondary air line 24 and thus through the valve element 10 or, in particular, were to be actively conveyed through it, the valve element 10 would then have the second flow resistance for the secondary air flowing through the secondary air line 24 in the return flow direction. In other words, the valve element 10 causes a first pressure loss of the gas when the gas, such as the secondary air or the exhaust gas, flows or would flow through the secondary air line 24 and thus through the valve element 10 in the injection direction.For example, when the gas, such as secondary air or exhaust gas, flows or would flow through the secondary air line 24 and thus through the valve element 10 in the return flow direction, the valve element 10 causes a second pressure loss of the gas, wherein the second pressure loss is greater than the first pressure loss. The valve element 10 is thus a backflow preventer or backflow limiter, since the valve element 10 at least limits or prevents a flow of exhaust gas, also referred to as backflow, in the return flow direction into the secondary air line 24 and / or within the secondary air line 24.In other words, the valve element 10 prevents excessive backflow of the exhaust gas from the exhaust tract 20 into and / or in the secondary air line 24, so that by means of the valve element 10, for example, it can be avoided that an excessive amount of the exhaust gas from the exhaust tract 20 penetrates into a line region of the secondary air line 24, the line region of which is arranged upstream of the valve element 10 when viewed along the injection direction.

[0047] In order to be able to carry out the secondary air injection particularly advantageously, the valve element 10, as can be seen particularly well in conjunction with Fig. 2 and Fig. 6, the device comprises a plurality of impact bodies 30 arranged successively along the injection direction. Each impact body 30 is rotationally symmetrical. The impact bodies 30 are connected to one another, in particular in such a way that the impact bodies 30 are formed integrally with one another. The interconnected, in particular integrally formed, impact bodies 30 thus form an assembled structural unit 32, which can, for example, be the valve element 10 or can be a component of the valve element 10.

[0048] Looks particularly good Fig. 5 that the valve element 10 is arranged in a longitudinal region L of the secondary air line 24, the longitudinal region L of which is delimited by a component of the internal combustion engine 12 that is formed separately from the valve element 10, wherein the component is the cylinder head 14 in the exemplary embodiment shown in the figures. This means that the longitudinal region L and thus the valve element 10 are arranged in the cylinder head 14, i.e., within the cylinder head 14. A particularly compact design of the valve element 10 can be realized, so that the valve element 10 can be arranged in the cylinder head 14. Furthermore, the valve element 10 and thus the inlet point E can be arranged particularly close to the respective exhaust valve 16 and in particular downstream of the exhaust valve 16, so that a particularly efficient and effective secondary air injection can be achieved.

[0049] Looks particularly good Fig. 2 and Fig. 4 it can be seen that the respective impact body 30 is assigned, in particular precisely, a respective ring 34. Particularly well from Fig. 4 that the rings 34 are connected to one another and to the impact bodies 30, in particular in that the rings 34 are formed integrally with one another and integrally with the impact bodies 30. The rings 34 and the impact bodies 30 thus form a one-piece and thus monoblock body 36, which can be the structural unit 32. In other words, the body 36 is integral and thus manufactured in one piece and not composed of several components formed separately from one another and thus connected to one another. Both the rings 34 and the impact bodies 30 are integral components of the one-piece and thus monoblock body 36. Furthermore, Fig. 2 and Fig. 4 that the respective impact body 30 engages in the respective ring 34 assigned to the respective impact body 30. In the present case, the impact bodies 30 are connected to the rings 34 and to one another via respective webs 38, which are formed integrally with the rings 34 and integrally with the impact bodies 30 and are thus also components of the body 36. For example, at least two, in particular at least or exactly three, webs 38 assigned to the respective impact body 30 are provided for each impact body 30. In particular, it can be provided that the respective webs 38 assigned to the respective impact body 30 are arranged uniformly distributed in the circumferential direction of the respective impact body 30 running around the injection direction and are thus spaced apart from one another, for example in pairs, by 120°.Overall, it can be seen that the impact bodies 30 and the rings 34 are combined by means of the webs 38 to form the structural unit 32, also referred to as the valve unit, in particular the body 36. The structural unit 32 or the valve element 10 as a whole can be particularly easily inserted into the longitudinal region L of the secondary air line 24, which is formed, for example, as a bore, and secured there, for example.

[0050] Out of Fig. 6 it is particularly clearly visible that the valve element 10 can be arranged particularly close to the outlet channel 18. This can particularly advantageously prevent an excessive amount of exhaust gas from the exhaust tract 20 from penetrating the secondary air line 24. Fig. 3 it can be seen that the respective webs 38 assigned to the respective impact body 30 are arranged uniformly distributed in the circumferential direction of the respective impact body 30, wherein the circumferential direction in Fig. 3 is illustrated by a double arrow 40.

[0051] The valve element 10 can have a sleeve 42, in which, for example, the body 36 can be arranged. In particular, the sleeve 42 can be formed separately from the body 36 and connected to the body 36, so that the sleeve 42 can be a component of the assembly 32. However, the sleeve 42 could be omitted.

[0052] In the exemplary embodiment shown in the figures, at least one part T of the cylinder head 14 that directly delimits the length region L is formed in one piece and is manufactured, for example, by casting. In particular, it is conceivable that the cylinder head 14 is formed entirely in one piece and is manufactured, for example, by casting.

[0053] How particularly good Fig. 2 and Fig.4, the respective impact body 30 has a respective first region B1, which continuously widens along the injection direction and is conical or truncated cone-shaped. Along the injection direction, the respective first region B1 of the respective impact body 30 is followed by a respective second region B2 of the respective impact body 30. The respective second region B2 of the respective impact body 30 continuously tapers along the injection direction, with the respective second region B2 being conical or truncated cone-shaped. Furthermore, the largest outer circumference, in particular outer diameter, of the respective first region B1 of the respective impact body 30 is larger than the largest outer circumference, in particular outer diameter, of the respective second region B2 of the respective impact body 30.The respective second region B2 merges into the respective first region B1 via a respective transition region UB of the respective impact body 30, or vice versa. For example, the respective transition region UB is curved along the return flow direction, with the respective transition region UB extending completely around the respective second region B2 in the circumferential direction of the respective impact body 30, which runs around the return flow direction or injection direction. The respective ring 34 is curved on a respective underside U facing the respectively assigned impact body 30 in the injection direction, specifically along the return flow direction and thus curved against the injection direction. List of reference symbols 10 Valve element 12 Internal combustion engine 14 cylinder head 16 Exhaust valve 18 exhaust channel 20 Exhaust system 22 Secondary air system 24 Secondary air line 26 Arrow 28 Arrow 30 impact bodies 32 building units 34 rings 36 bodies 38 jetty 40 double arrow E Discharge point B1 first area B2 second area L length range T Part U bottom UB transition area

Claims

[1] Internal combustion engine (12) for a motor vehicle, with an exhaust tract (20) through which exhaust gas from the internal combustion engine (12) can flow, and with a secondary air system (22) which has: - a secondary air line (24) through which air can flow as secondary air in an injection direction (26), whereby the secondary air flowing through the secondary air line (24) in the injection direction (26) can be introduced into the exhaust tract (20), and - at least one valve element (10) arranged in the secondary air line (24), which has a first flow resistance along the injection direction (26) and a second flow resistance that is greater than the first flow resistance along a return flow direction (28) opposite to the injection direction (26), whereby a return flow in the return flow direction (28) can be at least limited, characterized byin that the valve element (10) has a plurality of rotationally symmetrical impact bodies (30) which are arranged one after the other along the injection direction (26) and are connected to one another and are arranged in a longitudinal region (L) of the secondary air line (24), the longitudinal region (L) of which is delimited by a component (14) of the internal combustion engine (12) which is formed separately from the valve element (10), wherein the respective impact body (30) has a respective region (B1) which continuously widens along the injection direction (26). [2] Internal combustion engine (12) according to claim 1, characterized by that the component (14) is a cylinder head (14) of the internal combustion engine (12). [3] Internal combustion engine (12) according to claim 1 or 2, characterized by that at least one part (T) of the component (14) delimiting the length range (L) is formed in one piece. [4] Internal combustion engine (12) according to claim 3, characterized bythat at least the part (T) of the component (14) is produced by casting. [5] Internal combustion engine (12) according to one of the preceding claims, characterized by that the respective region (N1) is conical or truncated cone-shaped. [6] Internal combustion engine (12) according to one of the preceding claims, characterized by that along the injection direction (26) the respective region (B1) is followed by a respective second region (B2) of the respective impact body (30), the respective second region (B2) of which tapers continuously along the injection direction (26). [7] Internal combustion engine (12) according to claim 6, characterized by that the respective second region (B2) is conical or frustoconical. [8] Internal combustion engine (12) according to claim 6 or 7, characterized bythat the largest outer circumference of the respective first area (B1) is larger than the largest outer circumference of the respective second area (B2). [9] Internal combustion engine (12) according to one of the preceding claims, characterized by that a respective ring (34) of the valve element (10) is assigned to the respective impact body (30), wherein the respective impact body (30) engages in the respective ring (34) assigned to the respective impact body (30), wherein the rings (34) are connected to one another and to the impact bodies (30).

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