Internal combustion engines for motor vehicles, especially automobiles

Abstract

The present invention relates to an internal combustion engine (10) for a motor vehicle, the internal combustion engine (10) comprising an intake passage (16) through which air can flow, a compressor (20) for compressing air arranged in the intake passage (16), an exhaust gas passage (24) through which exhaust gas can flow, and a secondary air system (52), the secondary air system (52) being fluidly connected to the exhaust gas passage (24) at an inlet point (E) and to the intake passage (16) at a branch point (A1) arranged downstream of the compressor (20), at which point (A1) at least a portion of the air compressed by the compressor (20) can be branched off from the intake passage (16) by the secondary air system (52) and can be introduced as secondary air into the exhaust gas passage (24) at the inlet point (E). The secondary air system (52) is also fluidly connected to the intake air flow path (16) at a second branch point (A2) located upstream of the compressor (20) and includes a secondary air pump (54).

Description

[Technical Field]

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

[0002] Such an internal combustion engine for a motor vehicle, particularly an automobile, is known, for example from Patent Document 1. The internal combustion engine has an intake passage through which air can flow, and a compressor is arranged in the intake passage for compressing the air flowing through the intake passage. The internal combustion engine also has an exhaust gas passage through which exhaust gas from the internal combustion engine can flow, as well as a secondary air system, which is fluidly connected to the exhaust gas passage at at least one inlet point. The secondary air system is fluidly connected to the intake passage at a branch point arranged downstream of the compressor. At the branch point, the secondary air system allows at least a portion of the air compressed by the compressor to branch off from the intake passage and be introduced into the secondary air system. The air branched off from the intake passage at the branch point and subsequently introduced into the secondary air system can flow through the secondary air system and be guided by the secondary air system to the inlet point, where it is introduced into the exhaust gas passage. Furthermore, Patent Document 2 discloses an internal combustion engine including a combustion engine, a fresh air system having a compressor, an exhaust gas aftertreatment device, and an exhaust gas system having a temperature sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] DE102007057603A1 [Patent Document 2] DE102013226063A1 Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the invention is to improve an internal combustion engine of the type mentioned at the beginning so that it is possible to achieve a particularly low-emission operation. [Means for solving the problem]

[0005] This problem is solved by an internal combustion engine having the features of claim 1. Advantageous configurations, including preferred developments of the invention, are set forth in the further claims.

[0006] In order to improve an internal combustion engine of the type defined in the preamble of claim 1 and in particular to enable low-emission operation, the invention provides that a secondary air system is also fluidly connected to the intake air passage at a second branch point arranged upstream of the compressor, whereby the secondary air system can branch off at least a portion of the air flowing through the intake air passage upstream of the compressor from the intake air passage and introduce it into the secondary air system. Intake The air branched from the intake passage and introduced into the secondary air system flows through the secondary air system and is sent by the secondary air system to an introduction point where it is introduced into the exhaust gas passage as secondary air. Thus, the secondary air system can branch air from the intake passage both at the first branch point, i.e., downstream of the compressor, and at the second branch point, i.e., upstream of the compressor, and guide it as secondary air to the introduction point where it is introduced into the exhaust gas passage.

[0007] In this case, the secondary air system has a secondary air pump, which can feed the air branched off at the second branch point through the secondary air system and toward the inlet point, in particular into the exhaust gas duct. The present invention allows for particularly advantageous and customizable secondary air injection. Secondary air injection means that the air branched off at each branch point can be introduced as secondary air into the exhaust gas duct at the inlet point, in particular bypassing the combustion chambers of the internal combustion engine or bypassing all combustion chambers of the internal combustion engine. The air branched off from the intake duct at the first branch point, thus downstream of the compressor, is also called compressed air. The present invention makes it possible, in particular, for example, after a certain point in time to introduce both the compressed air and the air branched off from the intake duct at the second branch point into the exhaust gas duct, i.e., to inject it into the exhaust gas duct. For example, the inlet point can be arranged in the exhaust gas channel, in particular in the exhaust channel, which allows for particularly advantageous injection of secondary air into the exhaust gas duct. For example, the introduction point is arranged in an exhaust channel, which is formed or defined, in particular by the cylinder head of the internal combustion engine. In particular, several, in particular all, exhaust channels, in particular exhaust channels, of the internal combustion engine can have respective introduction points at which secondary air can be injected into the exhaust gas flow path. The present invention makes it possible to advantageously introduce a large amount of secondary air into the exhaust gas flow path, in particular in the entire operating range of an internal combustion engine, also called a combustion engine, which is preferably configured as a piston engine, and thus to achieve particularly low-emission operation of the internal combustion engine.

[0008] Further advantages, features and particularities of the invention will become apparent from the following description of preferred embodiments and with reference to the drawings, in which: The features and feature combinations mentioned in the above description and those mentioned below in the description of the figures and / or shown alone in only one figure are applicable not only in the respective combinations mentioned, but also in other combinations or alone without departing from the framework of the invention. [Brief explanation of the drawings]

[0009] [Figure 1] This drawing shows, in a sole view and diagrammatically, an internal combustion engine for a motor vehicle, in particular for a car, equipped with a secondary air system. DETAILED DESCRIPTION OF THE INVENTION

[0010] This single figure shows a schematic representation of an internal combustion engine 10 for a motor vehicle, in particular for an automobile. The internal combustion engine 10 has an engine block 12, also called a cylinder block, which defines cylinders 14 of the internal combustion engine 10. Each cylinder 14 defines a combustion chamber in which a combustion process takes place during combustion operation of the internal combustion engine 10. The combustion process results in exhaust gases from the internal combustion engine 10. The internal combustion engine 10 has an air-permeable intake passage 16, which guides the air flowing through the intake passage 16 to and within the combustion chambers of the internal combustion engine 10. The internal combustion engine also has an exhaust-gas turbocharger 18, which has a compressor 20 arranged in the intake passage 16 and a compressor wheel 22 arranged in the intake passage 16. The compressor wheel 22, and therefore the compressor 20, compress the air flowing through the intake passage 16. Compressing the air flowing through the intake passage 16 is also called supercharging, and the compressed air is also called charge air.

[0011] The internal combustion engine 10 also has an exhaust gas duct 24 through which the exhaust gases of the combustion chamber, and thus of the internal combustion engine 10, can flow. The exhaust gas turbocharger 18 has a turbine 26 arranged in the exhaust gas duct 24 and a turbine wheel 28 arranged in the exhaust gas duct 24, which can be driven by the exhaust gases flowing through the exhaust gas duct 24. The compressor wheel 22 can be driven by the turbine wheel 28 via a shaft 30 of the exhaust gas turbocharger 18, thereby compressing the air flowing through the intake duct 16. IntakeAn air filter 32 is disposed in the flow path 16 upstream of the compressor 20, i.e., upstream of the compressor wheel 22, and this air filter 32 filters the air flowing through the intake flow path 16. Furthermore, a throttle flap 34 is disposed in the intake flow path 16 downstream of the compressor 20 and upstream of the combustion chambers, and this throttle flap 34 can adjust the amount of air flowing into each combustion chamber.

[0012] A diverted air circulation system 36 is assigned to the compressor 20, which comprises a diverted air circulation line 38, which is fluidly connected to the intake air duct 16 at connection points V1 and V2. The diverted air circulation line 38 allows connection point V1 to branch off at least a portion of the air flowing through the intake air duct 16 from the intake air duct 16 and introduce it into the diverted air circulation line 38. The air introduced into the diverted air circulation line 38 can flow through the diverted air circulation line 38, be guided by the diverted air circulation line 38 to introduction point V2, and then re-enter the intake air duct 16 at connection point V2. It can be seen that connection point V2 is located downstream of the air filter 32 and upstream of the compressor wheel 22, while connection point V1 is located downstream of the compressor wheel 22 and upstream of the throttle flap 34. The diverted air circulation system 36 further includes a diverted air circulation valve 40, which is disposed in the diverted air circulation line 38. For example, the diverted air circulation valve 40 can adjust the amount of air flowing through the diverted air circulation line 38. In particular, the diverted air circulation valve 40 is configured as an electric diverted air circulation valve.

[0013] The turbine 26 includes a bypass device 42, which includes a bypass line 44. The bypass line 44 is fluidly connected to the exhaust gas flow path 24 at connection points V3 and V4. The bypass line 44 allows at least a portion of the exhaust gas flowing through the exhaust gas flow path 24 to be diverted from the exhaust gas flow path 24 at connection point V3 and introduced into the bypass line 44. The exhaust gas introduced into the bypass line 44 can flow through the bypass line 44, be guided by the bypass line 44 to connection point V4, and re-enter the exhaust gas flow path 24 at connection point V4. The exhaust gas flowing through the bypass line 44 bypasses the turbine 26 and therefore does not drive the turbine wheel 28. The bypass line 44 is also referred to as a bypass or wastegate. The bypass device 42 includes a bypass valve 46, also referred to as a bypass valve or wastegate valve, disposed within the bypass line 44. This bypass valve 46 makes it possible to adjust the amount of exhaust gas flowing through the bypass line 44. It can be seen that the connection point V3 is arranged upstream of the turbine 26, i.e., upstream of the turbine wheel 28, while the connection point V4 is arranged downstream of the turbine wheel 28, i.e., downstream of the turbine 26.

[0014] An exhaust gas aftertreatment device 48 is further assigned to the exhaust gas flow path 24, which is arranged downstream of the turbine 26, in particular downstream of the connection point V4. The exhaust gas of the internal combustion engine can flow through this exhaust gas aftertreatment device 48, thereby aftertreatment of the exhaust gas. For this purpose, the exhaust gas aftertreatment device comprises, for example, exhaust gas aftertreatment elements 50a-c. The exhaust gas aftertreatment element 50a is, for example, configured as a catalytic converter, in particular as a three-way catalytic converter. The exhaust gas aftertreatment element 50b is, for example, configured as a particulate filter, in particular as a gasoline particulate filter (OPF). The exhaust gas aftertreatment element 50c is, for example, configured as a catalytic converter. In particular, the internal combustion engine, also referred to as combustion engine or engine, can be configured as a gasoline engine.

[0015] The internal combustion engine 10 also has a secondary air system 52. This secondary air system 52 is fluidly connected to the intake air passage 16 at a first branch point A1. Furthermore, the secondary air system 52 is fluidly connected to the exhaust gas passage 24 at an inlet point E. In particular, at least one or even exactly one inlet point E may be provided per combustion chamber, at which inlet point E the secondary air system 52 is fluidly connected to the exhaust gas passage 24. In particular, it is conceivable that the inlet point E is arranged, in particular directly, in the exhaust gas channel, in particular in the discharge channel. For example, the discharge channel is formed, i.e., defined, by a cylinder head of the internal combustion engine 10. This cylinder head is configured separately from the engine block 12 and is connected to the engine block 12. In particular, this cylinder head forms a combustion chamber roof for each combustion chamber.

[0016] It can be seen that the first branch point A1 is located downstream of the compressor 20, and thus downstream of the compressor wheel 22. In the illustrated embodiment, the first branch point A1 is located downstream of the connection point V1 and upstream of the throttle flap 34. The secondary air system 52 can branch at least a portion of the air compressed by the compressor 20 from the intake air flow path at the branch point A1 and introduce it into the secondary air system 52. Since the branch point A1 is located downstream of the compressor wheel 22, the air branched from the intake air flow path 16 by the secondary air system 52 at the branch point A1 is also referred to as compressed air. This compressed air can enter the secondary air system 52, be guided by the secondary air system 52 to the respective introduction points E, and then exit the secondary air system 52 at the respective introduction points E and enter the exhaust gas flow path 24. The compressed air is therefore introduced, i.e., injected, into the exhaust gas flow path 24 as secondary air at the respective introduction points E. The introduction of air, also called compressor air or secondary air, branching off from the intake air flow path 16 at the branch point A and into the exhaust gas flow path 24 at the respective introduction point E is also called secondary air injection.

[0017] To enable particularly low-emission operation of the internal combustion engine 10, the secondary air system 52 is also fluidly connected to the intake air duct 16 at a second branch point A2. It can be seen that the second branch point A2 is arranged upstream of the compressor 20, thus upstream of the compressor wheel 22, in particular upstream of the connection point V2. The secondary air system 52 allows at least a portion of the air flowing through the intake air duct 16 upstream of the compressor 20 to be branched off from the intake air duct 16 at the second branch point A2 and introduced into the secondary air system 52. The air branched off from the intake air duct 16 at the second branch point A2 and introduced into the secondary air system 52, also known as precompressor air, is guided by the secondary air system 52 to a respective introduction point E, where it can be introduced, in particular injected, into the exhaust gas duct 24, in particular as further secondary air. It can be seen that both the compressed air and the pre-compressed air are used as secondary air, which is branched off from the intake air flow path 16 at the respective branch points A1 or A2 and introduced into the exhaust gas flow path 24 at the respective introduction points E. Each introduction point E is arranged upstream of the exhaust gas aftertreatment device 48. In the embodiment shown in the figures, each introduction point E is arranged upstream of the turbine 26, in particular upstream of the connection point V3.

[0018] The secondary air system 52 has a first branch Z1, which is fluidly connected to the intake air channel 16 at a second branch point A2 and to the exhaust gas channel 24 at a respective inlet point E. The secondary air system 52 has, in particular, an electrically operable secondary air pump 54, by means of which the pre-compressor air branched off at the second branch point A2 can be fed through the secondary air system 52, in particular via the first branch Z1, and supplied to the respective inlet point E. In this case, the secondary air pump 54 is arranged in the first branch Z1.

[0019] The secondary air system 52 further comprises a first non-return valve 56, which is arranged downstream of the secondary air pump 54 in the first branch Z1. This non-return valve 56 closes in the direction of the secondary air pump 54, thereby preventing air from flowing through branch Z1 in the direction of the secondary air pump 54. However, since this non-return valve 56 opens in the direction of the respective introduction point E, the non-return valve 56 allows secondary air, in particular pre-compressor air, to flow from the secondary air pump 54 to the respective introduction point E. The secondary air system 52 has a second branch Z2, which closes at the first branch point A1. Intake The second branch Z2 is fluidly connected to the flow path 16. This second branch Z2 is fluidly connected to the first branch Z1 at a junction M. It can be seen that the junction M is arranged downstream of the secondary air pump 54, in particular downstream of the check valve 56. The second branch Z2 is therefore open to the flow of compressed air. A second check valve 58 of the secondary air system 52 is arranged in the second branch Z2. The second check valve 58 directs the flow of compressed air in the direction of the junction M. Opening , Branch point A 1 In the direction of close .

[0020] The secondary air system 52 further comprises a shut-off valve 60, which is provided in addition to the check valves 56 and 58, and which is arranged in the second branch Z2 upstream of the check valve 58 and downstream of the branch point A1. The secondary air system 52 has a pressure sensor 62, which can detect the pressure in the secondary air system 52, in particular downstream of the junction M. The secondary air system 52 also comprises a valve element 64, which is arranged in the branch Z1. In this case, the valve element 64 is arranged downstream of the junction M, in particular downstream of the pressure sensor 62. The valve element 64 is, for example, a secondary air valve, in particular an exhaust gas combination valve. For example, the valve element 64 can adjust the amount of secondary air introduced into the exhaust gas flow path 24 at the respective introduction point E. It can be seen that at the junction point M, the compressed air and the pre-compressed air can be mixed, thus forming a total secondary air, and by means of the valve element 64, in particular the total secondary air amount can be adjusted, which can be or is introduced into the exhaust gas flow path 24 at the respective introduction point E. In one embodiment, the non-return valve 58 opens in the direction of the junction point M and closes in the direction of the branch point A1, thus allowing the flow of compressed air as secondary air, for example from the branch point A1 to the junction point M, i.e. blocking the flow of air from the junction point M to the branch point A1. [Explanation of symbols]

[0021] 10 Internal combustion engine 12 Engine block 14 cylinders 16 Intake passage 18 Exhaust gas turbocharger 20 Compressor 22 Compressor wheel 24 Exhaust gas flow path 26 Turbine 28 Turbine Wheel 30 shaft 32 Air filter 34 Throttle flap 36 Separate air circulation system 38 Separate air circulation line 40 Diversion air circulation valve 42 Detour device 44 Detour Line 46 Diversion valve 48 Exhaust gas aftertreatment device 50a-c Exhaust gas aftertreatment elements 52 Secondary Air System 54 Secondary air pump 56 Check valve 58 Check valve 60 Shut-off valve 62 Pressure Sensor 64 valve elements A1 First fork A2 Second fork E. Installation location M Junction V1 connection point V2 connection point V3 connection point V4 connection point Z1 First branch Z2 Second branch

Claims

1. An internal combustion engine (10) for a motor vehicle, comprising: an intake passage (16) through which air can flow; a compressor (20) disposed in the intake passage (16) for compressing the air flowing through the intake passage (16); an exhaust gas passage (24) through which exhaust gas from the internal combustion engine (10) can flow; and a secondary air system (52), the secondary air system (52) being fluidly connected to the exhaust gas passage (24) at at least one introduction point (E) and fluidly connected to the intake passage (16) at a first branch point (A1) disposed downstream of the compressor (20), wherein at least a portion of the air compressed by the compressor (20) can be branched from the intake passage (16) at the first branch point (A1) and can be introduced as secondary air into the exhaust gas passage (24) at the introduction point (E). The secondary air system (52) is also fluidly connected to the intake air flow path (16) at a second branch point (A2) arranged upstream of the compressor (20), so that at least a portion of the air flowing through the intake air flow path (16) upstream of the compressor (20) can be branched from the intake air flow path (16) at the second branch point (A2) by the secondary air system (52) and can be introduced as secondary air into the exhaust gas flow path (24) at the introduction point (E), and the secondary air system (52) has a secondary air pump (54), so that the air branched at the second branch point (A2) is supplied through the secondary air system (52) and supplied to the introduction point (E), the secondary air system (52) has a first branch (Z1), the first branch (Z1) is fluidly connected to the intake air flow path (16) at the second branch point (A2) and is fluidly connected to the exhaust gas flow path (24) at the introduction point (E), and the secondary air pump (54) is disposed within the first branch (Z1); the introduction point (E) is assigned to a combustion chamber of the internal combustion engine (10) and is arranged in an exhaust channel formed by a cylinder head of the internal combustion engine (10), the secondary air system (52) has a second branch (Z2) fluidly connected to the intake air flow path (16) at the first branch point (A1) and fluidly connected to the first branch (Z1) at a junction point (M); The internal combustion engine (10) is characterized in that a valve element (64) capable of adjusting the amount of the secondary air introduced into the exhaust gas flow path (24) at the introduction point (E) is arranged downstream of the confluence point (M).

2. 2. The internal combustion engine (10) according to claim 1, characterized in that in the first branch (Z1), a non-return valve (56) is arranged downstream of the secondary air pump (54), the non-return valve (56) closing in the direction of the secondary air pump (54) and opening in the direction of the introduction point (E).

3. 3. The internal combustion engine (10) according to claim 1 or 2, characterized in that a non-return valve (58) is arranged in the second branch (Z2), which closes in the direction of the first branch point (A1) and opens in the direction of the merging point (M).

4. 4. The internal combustion engine (10) according to claim 3, characterized in that an additional shut-off valve (60) is arranged in the second branch (Z2) upstream of the non-return valve (58) arranged in the second branch (Z2).

5. 3. The internal combustion engine (10) according to claim 2, characterized in that the junction (M) is arranged downstream of the non-return valve (56) arranged in the first branch (Z1).

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