Internal combustion engines in automobiles, especially motor vehicles

Abstract

The invention relates to an internal combustion engine (12) of a motor vehicle, comprising an exhaust gas flow path (20) through which exhaust gases of the internal combustion engine (12) can flow, and a secondary air system (22), the secondary air system having a secondary air line (24) through which air as secondary air can flow 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 gas flow path (20). The secondary air system has at least one valve element (10) arranged in the secondary air line (24), the valve element having a first flow resistance along the injection direction (26) and a second flow resistance along a counterflow direction (28) opposite to the injection direction (26) that is greater than the first flow resistance, whereby the counterflow in the counterflow direction (28) can at least be limited. The valve element (10) has a plurality of rotationally symmetric impact bodies (30), the plurality of impact bodies (30) being arranged successively along the injection direction (26) and connected to each other. The valve element (10) is disposed in a length region (L) of the secondary air line (24), the length region (L) being defined by a part (14) of the internal combustion engine (12) which is formed separately from the valve element (10).

Description

[Technical field]

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

[0002] US Pat. No. 5,399,433 discloses an internal combustion engine with a primary air system for supplying fresh air. A secondary air system is also provided, which branches off from the primary air system and is blown into the exhaust gas passage. From US Pat. No. 5,399,433 the known conduits can be referenced. Furthermore, US Pat. No. 5,399,433 discloses an internal combustion engine with exhaust gas recirculation and a recirculation valve for controlling the amount of exhaust gas recirculated to the fresh air system. Furthermore, from US Pat. No. 5,399,433 a method for operating an internal combustion engine is known. [Patent Document 1] DE102019217473A1 [Patent Document 2] US1329559 [Patent Document 3] DE102018107436A1 [Patent Document 4] DE102018106679A1 Summary of the Invention [Problem to be solved by the invention]

[0003] SUMMARY OF THE DISCLOSURE It is an object of the present invention to provide an internal combustion engine for a motor vehicle, in which secondary air injection can be realized in a particularly advantageous manner. [Means for solving the problem]

[0004] This problem is solved by an internal combustion engine having the features of claim 1. Advantageous configurations, including expedient developments of the invention, are set forth in the further claims.

[0005] The present invention relates to an internal combustion engine, also called engine or internal combustion engine, for motor vehicles, in particular motor vehicles, in particular passenger cars, for example configured as a reciprocating piston engine. This means that in the completed state, the motor vehicle has an internal combustion engine and can be driven by this internal combustion engine. The internal combustion engine has an exhaust gas flow path through which the exhaust gases of the internal combustion engine can flow. For example, during the ignition operation of the internal combustion engine, a combustion process takes place in the internal combustion engine, in particular in the combustion chambers of the internal combustion engine. During the respective combustion process, a fuel-air mixture, also simply called a mixture, is burned, as a result of which exhaust gases are generated. The exhaust gases leave the respective combustion chamber, enter the exhaust gas flow path and can flow through the exhaust gas flow path. The internal combustion engine also has a secondary air system, by means of which a secondary air injection can be carried out, as will be explained in more detail below. The secondary air system has a secondary air line, through which air as secondary air can flow in an injection direction, so that the secondary air flowing through the secondary air line in the injection direction can be introduced into the exhaust gas flow path. In other words, secondary air injection includes secondary air flowing through the secondary air line in the injection direction and thus being introduced by the secondary air line into the exhaust gas flow path, which is also referred to as injection of secondary air. The secondary air flowing through the secondary air line in the injection direction therefore flows in the direction of or towards the exhaust gas flow path. In particular, the secondary air is introduced, i.e. injected, into the exhaust gas flow path by the secondary air line bypassing the combustion chamber, or preferably all combustion chambers, of the internal combustion engine. This is not to be understood as meaning that the secondary air enters the exhaust gas flow path via one of the combustion chambers, but rather that the secondary air does not pass through the combustion chamber of the internal combustion engine on its way through the secondary air line into the exhaust gas flow path, and thus the secondary air bypasses the combustion chamber, or all combustion chambers, of the internal combustion engine. In other words again, the secondary air is introduced, i.e. injected, directly into the exhaust gas flow path by 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 gas flow path at least or exactly at one introduction point by the secondary air line.In that case, the introduction point is in particular arranged downstream of a combustion chamber or all combustion chambers of the internal combustion engine, for example the introduction point is arranged in the cylinder head of the internal combustion engine.

[0006] In the exhaust gas flow path, for example, particularly downstream of the inlet point, at least one exhaust gas aftertreatment element is arranged for aftertreatment of the exhaust gas. The exhaust gas aftertreatment element is, for example, a catalyst or contains a catalyst. The secondary air carried, i.e. introduced, into the exhaust gas flow path is used, in particular, to heat, i.e. heat the exhaust gas aftertreatment element. For this purpose, for example, fuel, i.e. unburned hydrocarbons, can react with oxygen from the secondary air in the exhaust gas flow path, so that the fuel burns, in particular with the release of heat. The released heat can effectively, in particular quickly, heat the exhaust gas aftertreatment element.

[0007] The secondary air is, for example, from the intake air flow path of the internal combustion engine, also referred to as the intake flow path. Air, also referred to as fresh air, can flow through the intake air flow path. The fresh air is led by the intake air flow path to the combustion chamber and enters the combustion chamber. In that case, for example, at least a part of the fresh air flowing through the intake air flow path can be branched off from the intake air flow path and introduced into the secondary air line, in particular by means of a secondary air line. The part of the fresh air introduced into the secondary air can flow through the secondary air line as the aforementioned secondary air and is then introduced, in particular by means of the secondary air line, directly into the exhaust gas flow path. 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 from the secondary air line.

[0008] The secondary air system also has at least one valve element arranged in the secondary air line, thus allowing the secondary air to flow, in particular in the injection direction, which valve element has a first flow resistance along the injection direction, in particular a first flow resistance for a gas, for example secondary air. The valve element has a second flow resistance along a counterflow direction opposite to the injection direction, in particular for a gas, which is in particular significantly larger than the first flow resistance. Thereby, the valve element can at least limit, in particular prevent, a backflow, in particular in the counterflow direction of a gas. The valve element is therefore a backflow restrictor or backflow preventer, since it prevents a particularly undesirable, for example a backflow of a gas through or in the secondary air line.

[0009] As mentioned above, the aforementioned gas may be secondary air. The valve element therefore provides, for example, a first flow resistance to the secondary air, seen along the injection direction, and a second flow resistance, seen along the counterflow direction. Furthermore, the gas may be exhaust gas. In other words, assuming that the exhaust gas is passed or flows through the secondary air line in the injection direction, the valve element has or will provide a first flow resistance to the exhaust gas flowing through the secondary air line in the injection direction. However, along the counterflow direction, the valve element has a second flow resistance that is greater than the first flow resistance. This secondary air and the exhaust gas may be considered to be very similar or identical with respect to their flow behavior, in particular with respect to the flow resistance of the valve element, whereby the valve element, on the one hand, allows the secondary air to flow through the secondary air line and thus through the valve element in the injection direction and thus to be conveyed in particular directly into the exhaust gas flow path. On the other hand, the valve element prevents or blocks an excessive flow of the exhaust gas through the valve element and thus through the secondary air line in the counterflow direction opposite to the injection direction. The valve element thereby prevents an excessive amount of exhaust gas from flowing from the exhaust gas flow path into the secondary air line and / or an excessive intrusion of exhaust gas from the exhaust gas flow path into the secondary air line. For example, for this purpose, the valve element is designed in such a way that it generates a first pressure loss of the gas or gas flow when gases, such as, for example, secondary air and exhaust gas, pass or are supposed to pass through the valve element in the inlet direction. Furthermore, the valve element generates a second pressure loss of the gas or gas flow when gases, such as, for example, secondary air or exhaust gas, pass or are supposed to pass through the valve element in the reverse flow direction or are particularly actively, thus for example forced, whereby the second pressure loss is particularly designed to be significantly greater than the first pressure loss. This makes it possible to avoid excessive inflows or reverse flows into or in the secondary air line.

[0010] In order that the secondary air can then be introduced, i.e. carried or injected, particularly advantageously by the secondary air line and thus via the valve element into the exhaust gas flow path, it is provided according to the invention that the valve element has a number of impact bodies arranged along the injection direction or successively, i.e. one after the other, each impact body being rotationally symmetrical when viewed by itself, i.e. alone. On its way through the secondary air line and thus through the valve element towards the exhaust gas flow path, the secondary air first comes to and flows around a first one of the impact bodies, and subsequently the secondary air comes to and flows around a second one of the impact bodies. In that case, the second impact body is arranged downstream of the first one, i.e. along the injection direction. Since the impact bodies are connected to one another, the impact body itself, i.e. when viewed by itself, is an assembled component unit which can be handled, for example, assembled, i.e. installed, as a whole, for example by a person or a robot in the assembled state. In particular, the component unit can be a valve element.

[0011] The valve element and thus the structural unit are arranged in a length region of the secondary air line, the length region being defined by a part of the internal combustion engine which is formed separately from the valve element and thus separately from the structural unit. The invention makes it possible to simultaneously handle, and thus for example move, relative to the part and install, the structural unit and thus a plurality of impact bodies and / or groups of impact bodies, for example when manufacturing an internal combustion engine, in which case, for example, the structural unit is moved into the length region and thus arranged in the length region.

[0012] Basically, the impact bodies are considered to be bodies that are formed separately from one another and connected to one another. However, it has proven to be particularly advantageous if the impact bodies are formed in one piece with one another. This means that the impact bodies are integral components of a one-piece body, i.e. a body made in one piece and therefore made in one piece, which body is not made up of several parts that are formed separately from one another, but rather the body is formed as a monoblock and the impact bodies are formed by this body.

[0013] Furthermore, it is provided in particular that the valve element is formed as a passive valve element without moving parts, whereby in particular excessive and undesirable backflow of exhaust gases into or in the secondary air line can be avoided.

[0014] In an advantageous embodiment of the invention, in order to be able to bring, in particular inject, secondary air into the exhaust gas flow path in a particularly advantageous manner, it is provided that the component is the aforementioned cylinder head of an internal combustion engine, whereby, for example, each combustion chamber is partially defined by a respective combustion chamber roof, which in turn is formed by the cylinder head.

[0015] In particular, the length region is directly defined by the part, in particular by the inner peripheral, and therefore in particular by the concave, outer jacket surface of the part, e.g., the valve element, in particular the outer peripheral, and therefore in particular the convex, outer jacket surface of the valve element, directly contacts the part, in particular the inner peripheral, outer jacket surface.

[0016] A further embodiment is characterized in that at least a portion of the part, which in particular directly defines the length region, is made in one piece. This can be understood in particular to mean that at least a portion of the part is made in one piece, and therefore in one piece, and therefore formed as a monoblock, whereby the portion of the part is not made up of several parts that are made separately from one another and joined together. This allows the secondary air to be introduced into the exhaust gas duct in a particularly easy and particularly inexpensive way.

[0017] In order to be able to realise a particularly advantageous, particularly cheap, effective and efficient secondary air injection, a further embodiment of the invention provides for at least a part of the part to be produced by casting and thus formed as a cast part.

[0018] In a further, particularly advantageous embodiment of the invention, each impact body has a respective area that is continuously expanding along the injection direction, i.e. as seen in the injection direction. This allows the first flow resistance to be advantageously small. At the same time, the second flow resistance can be advantageously large. This allows the valve element, on the one hand, to be designed particularly compact, so that the valve element and thus the secondary air line and also the introduction point can be positioned particularly advantageously. On the other hand, an undesirable flow of exhaust gases into and / or in the secondary air line can be avoided.

[0019] The valve element thus functions as a non-return valve or a type of non-return valve, but in particular without any moving parts, whereby a particularly compact design of the valve element can be realized, whereby the valve element and subsequently the secondary air line and in particular the introduction point can be advantageously positioned, whereby a particularly advantageous secondary air injection can be realized.

[0020] In order to be able to realize the respective flow resistance in a particularly advantageous manner, a further embodiment of the invention provides for the respective region which widens continuously along the injection direction to be formed so as to have a conical or frustoconical shape.

[0021] Each successively expanding region along the injection direction is also referred to as a first region.

[0022] A further embodiment provides that along the injection direction, i.e. as seen in the injection direction, the respective first region of the respective impact body is followed by the respective second region of the respective impact body, which respectively tapers along the injection direction, i.e. in the injection direction, whereby the flow resistance can be formed in a particularly advantageous manner, while at the same time a particularly compact design of the valve element can be realized.

[0023] It has proven to be particularly advantageous if the respective second regions are designed in a conical or frustoconical shape, which on the one hand ensures a particularly advantageous flow of the secondary air in the injection direction and thus into the exhaust gas flow path, and on the other hand advantageously prevents undesirable backflows of the exhaust gases in the secondary air line.

[0024] In order, on the one hand, to enable the secondary air to pass particularly well through the secondary air line in the injection direction and, on the other hand, to avoid excessive backflow of exhaust gases and, at the same time, to achieve a compact construction of the valve element, it is provided in a further embodiment of the invention that the maximum circumference, in particular the maximum outer diameter, of the respective first region is greater than the maximum or greatest circumference, in particular the outer diameter, of the respective second region.

[0025] It is further conceivable that the respective second region transitions into the respective first region via a respective transition region, in which case the respective transition region is in particular curved in the counterflow direction, i.e. against the injection direction. In particular, the transition region is a ring region that extends in the circumferential direction of the respective impact body around the injection direction, in particular completely around the respective second region. As a result, excessive backflow of exhaust gases in the secondary air line can be advantageously avoided.

[0026] Finally, it has proven to be particularly advantageous if each ring of the valve element is assigned to each impact body and each impact body engages with the ring assigned to the respective impact body. In that case, the rings are connected to one another and to the impact body, whereby in particular the rings are components of a structural unit. In that case, it is conceivable that the rings are formed in one piece with one another, whereby in particular the rings are integral components of the ring body. In particular, it is conceivable that the rings, and thus the ring body, are formed in one piece with the aforementioned body and thus in one piece with the impact body. In particular, it is therefore conceivable that both the ring and the impact body are integral components of the aforementioned body formed as a monoblock, which body is made in one piece, thus in one piece, and therefore does not consist of several parts that are formed separately from one another and connected to one another. As a result, a particularly compact construction of the valve element can be realized, whereby in particular the introduction point can be advantageously positioned. As a result, a particularly advantageous secondary air injection can be realized.

[0027] For example, the internal combustion engine is a gasoline engine. In particular, the internal combustion engine may be a supercharged internal combustion engine. This can in particular be understood as the internal combustion engine having at least one exhaust gas turbocharger, which includes a compressor arranged in the intake air passage and a turbine arranged in the exhaust gas passage. The exhaust gas can drive the turbine, which in turn drives the compressor. By driving the compressor, fresh air flowing through the intake air passage can be compressed by the compressor.

[0028] The present invention is based, inter alia, on the following findings and considerations: Secondary air injection is used, in particular in gasoline engines supercharged by exhaust gas turbochargers, in order to bring the temperature of the exhaust gas aftertreatment elements, in particular by after-reaction of the exhaust gas or of the components contained in the exhaust gas, particularly quickly to a favorable operating temperature, for example after a cold start of the internal combustion engine, and thus to avoid excessive emissions of undesirable components. In particular, said components can be fuel, i.e. unburned hydrocarbons. Each combustion chamber is, for example, assigned at least one respective exhaust passage, which is arranged in particular in the above-mentioned cylinder head. In particular, the respective exhaust passage is delimited in particular directly by the cylinder head. In that case, at least one or more exhaust valves are assigned to each combustion chamber, which are movable, in particular translationally, relative to the cylinder head. The respective exhaust gases can leave the respective combustion chamber via the respective exhaust valves and flow into the respective exhaust passage. The exhaust passages are also called exhaust gas passages.

[0029] It has proven to be particularly effective if the secondary air is injected into the respective exhaust passage, in particular into each individual exhaust gas passage, immediately after each exhaust valve or after each exhaust valve. In particular, the respective exhaust passage or passages are components of the exhaust gas flow path. In that case, the operating strategy of the internal combustion engine can be designed to achieve high loads at low speeds and therefore high average pressures even in the operating phases in which the secondary air is injected into the exhaust gas flow path, in order to enable operation with as little fuel consumption as possible. In particular, the respective exhaust passages are components of the exhaust gas flow path. However, in that case, problems may arise in that the exhaust gas backpressure, in particular the exhaust impact of the exhaust gases, makes it very difficult to inject a sufficient amount of secondary air in the respective exhaust gas passage and thus in the exhaust gas flow path. For example, if the pressure of the secondary air provided by the air pump, also known as the secondary air pump, is insufficient, then every exhaust impact will result in a large amount of exhaust gas backflow into the secondary air line and thus into the secondary air passage which is in particular directly defined by the secondary air line, and if no appropriate countermeasures are taken, the average flow rate of the secondary air will no longer be sufficient to sufficiently react in the exhaust gas flow path and thus to sufficiently heat the exhaust gas aftertreatment elements.

[0030] A possible solution to this problem is that the secondary air pump is provided with particularly high performance, i.e. a particularly powerful secondary air pump is used. For example, the secondary air pump is an electric secondary air pump and can therefore be electrically operated. However, this results in the disadvantage that the power consumption of the secondary air pump is very high, which places an additional load on the electrical system of the vehicle. Furthermore, the secondary air line and, for example, a secondary air valve arranged in the secondary air line and designed to regulate the amount of secondary air introduced into the exhaust gas flow path must withstand the pressure or high pressure of the secondary air, which leads to larger installation space, weight and costs for the secondary air line and the secondary air valve. In particular, the secondary air valve is arranged upstream of the valve element, viewed along the injection direction.

[0031] It has been found that check valves in the secondary air or manifolds passing outside the cylinder head are not sufficient to prevent the backflow of exhaust gases, in particular into the injection passages of the individual combustion chambers. Due to the compressibility of the secondary air, long passages also allow the undesired ingress of exhaust gases into the secondary air line. It is therefore advantageous to arrange a backflow preventer or backflow restrictor, for example a valve element, in particular close to an exhaust valve or respectively a number of exhaust valves. It is particularly conceivable that each or each combustion chamber is assigned at least or exactly one respective inlet point at which the secondary air can be introduced into the exhaust gas flow passage. In that case, it is particularly advantageous if a valve element, for example embodied as a backflow preventer or backflow restrictor, is arranged in particular 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 must be particularly compact. This can be achieved by the invention. The valve element of the internal combustion engine according to the invention therefore represents a countermeasure to prevent an excessive backflow of exhaust gases into or in the secondary air line. According to the invention, a particularly compact design of the valve element can be realized, so that the valve element can be arranged particularly close to or behind the respective exhaust valve and in that case in the cylinder head, in particular, so that an especially large number of impact bodies can also be realized, so that excessive backflow can be particularly well avoided.

[0032] Conventional ball check valves are precluded from preventing or restricting unwanted backflow into or in the secondary air line because their mass inertia is too large. Even flap and plate valves are not suitable for use in secondary air lines because they can lead to service life problems. They are also subject to fouling with soot particles from combustion if exhaust gases enter the secondary air passage or line, at least temporarily.

[0033] In comparison with conventional solutions, the invention then allows, on the one hand, a particularly compact design of the valve element, which can be arranged particularly close to the respective exhaust valve of the respective combustion chamber, and in that case particularly in the cylinder head, whereby, on the one hand, advantageous secondary air injection can be achieved, and, on the other hand, excessive backflow of exhaust gases into and / or in the secondary air line can be avoided.

[0034] In particular, the valve element of the internal combustion engine according to the invention can be a Tesla valve or can be configured like a Tesla valve. In particular, it is conceivable that the respective ring is rotationally symmetrical with respect to an axis which is the same as the axis of rotational symmetry of the respective impact body. Due to its compactness, the valve element of the internal combustion engine according to the invention can be installed in a secondary air intake, for example the aforementioned length region, which is configured, for example, as a bore, which is only slightly larger than the conventional solutions.

[0035] In particular, due to the compactness of the valve element and the rotationally symmetrical design of the impact body, it is possible to arrange the valve element very close to the exhaust passage or exhaust valve. The volume of secondary air between the respective exhaust valve and the exhaust passage is therefore very small. Nevertheless, a large number of impact bodies can be realized. For example, each impact body and each ring assigned to each impact body form a ring-impact body pair, in particular a large number of ring-impact body pairs can be realized. As a result, a particularly high blocking effect can be achieved, whereby an excessive backflow of exhaust gases into and / or in the secondary air line can be avoided. Thus, in the event of an exhaust gas surge, only small amounts of exhaust gas can enter the secondary air line, so that the surge effect of the exhaust gas turbocharger or turbine can be eliminated. Furthermore, large amounts of secondary air can be easily blown into the exhaust gas flow path without the use of complex, costly and heavy secondary air pumps. As a result, the heating effect for heating the exhaust gas aftertreatment element is improved compared to conventional solutions, and the time until a significant conversion rate of the exhaust gas aftertreatment element is reached can be shortened. This allows a particularly low-emission operation of the internal combustion engine to be achieved, and since almost no exhaust gases penetrate into the secondary air line, excessive build-up of dirt and soot in the secondary air line, which could block the cross section of the secondary air line during long periods of operation, is prevented.

[0036] In particular, the secondary air system has the aforementioned secondary air valve, by means of which the secondary air line can, for example, be switched off in particular completely, i.e. fluidically blocked. In particular, since the secondary air valve is not required for the majority of the operation of the internal combustion engine, the secondary air valve can prevent a backflow of exhaust gases, particularly at high loads, and thus a leakage of exhaust gases through the secondary air system, by particularly completely fluidically blocking the secondary air line, which in particular allows the secondary air injection to be switched off by the secondary air valve being in particular completely fluidically blocked. In particular, the secondary air valve is a change-over valve. Viewed along the injection direction, the secondary air valve is arranged upstream of the valve element, in this case in particular in the secondary air line. The valve element of the internal combustion engine according to the invention has a particularly advantageous blocking effect, so that the secondary air valve can be particularly advantageously protected by the valve element from fouling and thus from malfunctions and premature failures, in order to prevent an excessive backflow of exhaust gases into the secondary air line.

[0037] Other advantages, features and specifics of the present invention will become apparent from the following description of preferred embodiments and with reference to the drawings. The features and combinations of features mentioned in the above description and in the following description of the figures and / or shown only in the figures can be used in other combinations or alone without departing from the scope of the present invention, rather than being used in the respective combinations presented. [Brief description of the drawings]

[0038] [Figure 1] 1 is a schematic side view of a valve element of a secondary air system of an internal combustion engine of a motor vehicle; [Diagram 2] 2 is a schematic longitudinal sectional view of the valve element taken along the line AA in FIG. 1. [Diagram 3] FIG. 2 is a schematic top view of a valve element. [Figure 4]FIG. 4 is a schematic longitudinal sectional view of the valve element taken along line BB in FIG. 3. [Diagram 5] 1 is a schematic cross-sectional view of a portion of an internal combustion engine with a secondary air system and a valve element; [Figure 6] FIG. 2 is another partial schematic cross-sectional view of the internal combustion engine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] In the various figures, identical or functionally identical elements are provided with the same reference numbers. FIG. 1 shows a schematic side view of a valve element 10 of a secondary air system of an internal combustion engine of a motor vehicle. In FIGS. 5 and 6, the internal combustion engine is shown in respective schematic partial cross-sections and is designated by the reference number 12. The internal combustion engine 12 has an exhaust gas flow path through which the exhaust gases of the internal combustion engine 12 can flow and a secondary air system. In particular, the internal combustion engine 12 has a plurality of combustion chambers. Each combustion chamber is, for example, partially defined by a respective cylinder of the internal combustion engine 12. For example, each cylinder is defined 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 formed as a reciprocating piston engine. A respective piston is translationally accommodated in each cylinder, whereby each combustion chamber is partially defined by the respective cylinder and partially by the respective piston translationally accommodated in the respective cylinder. Furthermore, each combustion chamber is partially defined by a respective combustion chamber roof. The respective combustion chamber roof is formed by a cylinder head 14 of the internal combustion engine 12. This cylinder head 14 is formed separately from the engine housing and is connected to it. From FIG. 5 it can be seen that at least one exhaust valve 16 and at least one exhaust passage 18 are assigned to each combustion chamber. In particular, at least or exactly two exhaust valves 16 are assigned to each combustion chamber. During the ignition operation of the internal combustion engine 12, a combustion process takes place in the respective combustion chamber. In the respective combustion process, a fuel-air mixture, also simply called mixture, is burned. As a result, the aforementioned exhaust gases are generated. The exhaust gases leave the respective combustion chamber and flow via the respective exhaust valve 16 assigned to the respective combustion chamber into the respective exhaust passage 18 assigned to the respective combustion chamber, so that they can flow through the respective exhaust passage 18, also called exhaust passage or exhaust line. The respective exhaust passage 18 is a component of the above-mentioned exhaust gas flow path of the internal combustion engine 12, which exhaust gas flow path is designated with 20. It can be seen that the respective exhaust passage 18 is arranged in the cylinder head 14.In that case, the respective exhaust passage 18 is in particular directly formed, i.e. defined, by the cylinder head 14 .

[0040] The secondary air system of the internal combustion engine 12, which can be seen in detail in FIGS. 5 and 6 and is designated there by the reference number 22, has, in particular per combustion chamber, at least or exactly one secondary air line 24, through which air as secondary air can flow in an injection direction, which is indicated in FIG. 5 by the arrow 26. This allows the secondary air flowing through the secondary air line 24 in the injection direction (arrow 26) to be introduced into the exhaust passage 18 and thus into the exhaust gas flow path 20. In the exhaust gas flow path 20, at least a first exhaust gas aftertreatment element for aftertreatment of the exhaust gases is arranged downstream of the exhaust passage 18. For example, the exhaust gas aftertreatment element comprises a catalyst. The catalyst can be heated particularly quickly to its operating temperature by means of the secondary air. The introduction of the secondary air into the exhaust gas flow path 20 is also called injection of the secondary air or secondary air injection. From FIG. 5, it can be seen that the secondary air flowing through the secondary air line 24 in the injection direction can leave the secondary air line 24 at the introduction point E and enter the exhaust passage 18 and thus into the exhaust gas flow path 20. In particular, the secondary air line 24 merges with the exhaust passage 18, and thus with the exhaust gas flow path 20, at an entry point E. In FIG.

[0041] The secondary air system 22 also has, in particular for each secondary air line 24, a valve arranged in the secondary air line 24, this valve being the valve element 10 shown in FIG. 1. The valve element 10 has a first flow resistance along the injection direction, in particular for the gas flowing through the secondary air line 24 in the injection direction. Along a counterflow 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 counterflow direction, which is in particular significantly larger than the first flow resistance. By gas, for example, both secondary air and exhaust gas can be understood. Then, for example, if secondary air flows through the secondary air line 24 and thus through the valve element 10 in the injection direction, the valve element 10 has a first flow resistance to the secondary air. For example, if secondary air flows through the secondary air line 24 and thus through the valve element 10 in the counterflow direction or is in particular actively conveyed through it, the valve element 10 has a second flow resistance to the secondary air flowing through the secondary air line 24 in the counterflow direction. In other words, when a gas, such as secondary air or exhaust gas, passes or is considered to pass through the secondary air line 24 in the inlet direction and thus through the valve element 10, the valve element 10 creates a first pressure loss of the gas. When a gas, such as secondary air or exhaust gas, passes or is considered to pass through the secondary air line 24 in the reverse flow direction and thus through the valve element 10, the valve element 10 creates a second pressure loss of the gas, such as the second pressure loss being greater than the first pressure loss. Thus, the valve element 10 is a backflow preventer or restrictor because the flow of exhaust gas into and / or in the secondary air line 24, also referred to as reverse flow and taking place in the reverse flow direction, is at least limited or prevented by the valve element 10. In other words again, the valve element 10 prevents excessive backflow of exhaust gas from the exhaust gas flow path 20 into the secondary air line 24 and / or in the secondary air line, thereby making it possible for the valve element 10 to avoid the intrusion of excessive amounts of exhaust gas from the exhaust gas flow path 20 into the line area of ​​the secondary air line 24 that is located upstream of the valve element 10, for example as viewed along the injection direction.

[0042] In that case, in order to be able to carry out the secondary air injection particularly advantageously, the valve element 10 has a number of impact bodies 30 arranged successively along the injection direction, as can be particularly clearly seen in Fig. 2 and Fig. 6 taken together. Each impact body 30 is itself formed rotationally symmetrically. The impact bodies 30 are in particular connected to one another in such a way that they are formed in one piece with one another. The impact bodies 30 connected to one another, in particular formed in one piece with one another, thus form an assembled constructional unit 32, which may for example be the valve element 10 or may be a component of the valve element 10.

[0043] From Fig. 5 it can be seen particularly well that the valve element 10 is arranged in a length region L of the secondary air line 24, which is delimited by a part of the internal combustion engine 12 formed separately from the valve element 10, which part in the illustrated exemplary embodiment is the cylinder head 14. This means that the length region L and thus the valve element 10 is arranged in the cylinder head 14, i.e. inside the cylinder head 14. A particularly compact construction type of the valve element 10 can be realized, whereby the valve element 10 can be arranged in the cylinder head 14. Furthermore, this allows the valve element 10, and thus the introduction point E, to be arranged particularly close to the respective exhaust valve 16 and in that case particularly downstream of the exhaust valve 16, whereby a particularly efficient and effective secondary air injection can be realized.

[0044] From figures 2 and 4 it can be seen particularly well that each impact body 30 is assigned in particular exactly one respective ring 34. From figure 4 it can be seen particularly well that the rings 34 are connected to each other and to the impact body 30, in particular by being formed in one piece with each other and with the impact body 30. The ring 34 and the impact body 30 therefore form a one-piece body 36, thus formed as a monoblock, which body 36 can be a structural unit 32. In other words, the body 36 is made in one piece, thus in one piece, and not composed of several parts formed separately from each other and thus connected to each other. In that case, both the ring 34 and the impact body 30 are integral components of the one-piece body 36, thus formed as a monoblock. Furthermore, from figures 2 and 4 it can be seen that each impact body 30 engages with the respective ring 34 assigned to the respective impact body 30. Here, the impact bodies 30 are connected to the ring 34 and to each other via respective webs 38, which are formed in one piece with the ring 34 and in one piece with the impact body 30 and are therefore 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 on each impact body 30. In particular, it can be provided that the respective webs 38 assigned to the respective impact body 30 are arranged evenly distributed in the circumferential direction of the respective impact body 30 extending around the injection direction and are thus spaced apart from each other by 120°, for example in pairs. It can be seen that, overall, the impact bodies 30 and the ring 34 are integrated by the webs 38 into the constructional unit 32, also called valve unit, in particular into the body 36. The constructional unit 32 or the entire valve element 10 can be particularly easily inserted into the length region L of the secondary air line 24, which is formed, for example, as a bore, and can be fixed there, for example.

[0045] It can be seen particularly well from Figure 6 that the valve element 10 can be arranged particularly close to the exhaust passage 18. This can be particularly advantageously prevented in that an excessive amount of exhaust gas from the exhaust gas flow passage 20 enters the secondary air line 24. It can be seen particularly well from Figure 3 that the respective webs 38 assigned to the respective impact body 30 are arranged evenly distributed in the circumferential direction of the respective impact body 30, the circumferential direction being indicated in Figure 3 by a double arrow 40.

[0046] The valve element 10 can have, for example, a sleeve 42 in which 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, whereby the sleeve 42 can be a component of the structural unit 32. However, the sleeve 42 can also be omitted.

[0047] In the exemplary embodiment shown in the figures, at least a portion T of the cylinder head 14, which in particular directly defines the length region L, is formed in one piece, for example produced by casting. In particular, it is conceivable that the entire cylinder head 14 is formed in one piece, for example produced by casting.

[0048] As can be seen particularly well from Fig. 2 and Fig. 4, each impact body 30 has a respective first region B1 which expands continuously along the injection direction and is formed in a conical or frustoconical shape. Along the injection direction, the respective first region B1 of the respective impact body 30 is followed by the respective second region B2 of the respective impact body 30. The respective second region B2 of the respective impact body 30 tapers continuously along the injection direction and the respective second region B2 is formed in a conical or frustoconical shape. Furthermore, the maximum circumference, in particular the outer diameter, of the respective first region B1 of the respective impact body 30 is greater than the maximum circumference, in particular the outer diameter, of the respective second region B2 of the respective impact body 30. The respective second region B2 transitions into the respective first region B1 via the respective transition region UB of the respective impact body 30 or vice versa. In this case, for example, the respective transition region UB is curved along the counterflow direction, for example the respective transition region UB extends completely around the respective second region B2 in a circumferential direction extending around the counterflow or injection direction of the respective impact body 30. Each ring 34 is formed with a curved respective underside U facing towards the respectively assigned impact body 30 in the injection direction, strictly speaking curved along the counterflow direction and therefore against the injection direction. [Explanation of symbols]

[0049] 10 Valve elements 12 Internal combustion engine 14 Cylinder head 16 Exhaust valve 18 Exhaust passage 20 Exhaust gas flow path 22 Secondary Air System 24 Secondary Air Line 26 Arrow 28 Arrow 30 Impactor 32 Configuration Units 34 Ring 36 skeleton 38 Web 40 Double Arrow E. Installation location B1 First region B2 Second region L Length region T Portion U Bottom surface UB Transition region

Claims

1. An internal combustion engine (12) for a motor vehicle, comprising an exhaust gas flow path (20) through which exhaust gases of the internal combustion engine (12) can flow, and a secondary air system (22), the secondary air system (22) comprising: - a secondary air line (24) through which air as secondary air can flow 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 gas flow path (20); and the internal combustion engine (12) having at least one valve element (10) arranged in the secondary air line (24), the valve element (10) having a first flow resistance along the injection direction (26) and a second flow resistance along a counterflow direction (28) opposite to the injection direction (26) that is greater than the first flow resistance, thereby being able to at least limit a counterflow taking place in the counterflow direction (28), 1. The internal combustion engine (12), characterized in that the valve element (10) has a plurality of rotationally symmetrical impact bodies (30), which are arranged successively along the injection direction (26) and connected to one another, thereby forming a structural unit (32), the valve element (10) and the structural unit (32) being arranged in a length region (L) of the secondary air line (24), the length region (L) being defined by a part (14) of the internal combustion engine (12), which part is formed separately from the valve element (10) and from the structural unit (32).

2. 2. The internal combustion engine (12) of claim 1, wherein the component (14) is a cylinder head (14) of the internal combustion engine (12).

3. 3. An internal combustion engine (12) according to claim 1 or 2, characterized in that at least one portion (T) defining said length region (L) of said part (14) is formed in one piece.

4. 4. An internal combustion engine (12) according to claim 3, characterized in that at least said portion (T) of said component (14) is produced by casting.

5. 5. An internal combustion engine (12) according to any one of claims 1 to 4, characterized in that each impact body (30) has a respective area (B1) which increases continuously along the injection direction (26).

6. 6. An internal combustion engine (12) according to claim 5, characterized in that each said region (N1) is formed in a conical or frustoconical shape.

7. 7. An internal combustion engine (12) according to claim 5 or 6, characterized in that along the injection direction (26) each said region (B1) is followed by a respective second region (B2) of each said impact body (30), each said second region (B2) being continuously tapered along the injection direction (26).

8. 7. An internal combustion engine (12) according to claim 6, characterized in that each second region (B2) is formed in a conical or frustoconical shape.

9. 9. An internal combustion engine (12) according to claim 7 or 8, characterized in that the maximum outer periphery of each of said first regions (B1) is greater than the maximum outer periphery of each of said second regions (B2).

10. 10. An internal combustion engine (12) according to any one of claims 1 to 9, characterized in that each of the impact bodies (30) is assigned to a respective ring (34) of the valve element (10), each of the impact bodies (30) engages with a respective of the ring (34) assigned to each of the impact bodies (30), the rings (34) being connected to each other and to the impact bodies (30).

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