GB2590942A

GB2590942A - Air intake system for use in an internal combustion engine

Info

Publication number: GB2590942A
Application number: GB2000227.5A
Authority: GB
Inventors: Thomas Holland Richard; Ramasamy Prabhu
Original assignee: Perkins Engines Co Ltd
Current assignee: Perkins Engines Co Ltd
Priority date: 2020-01-08
Filing date: 2020-01-08
Publication date: 2021-07-14
Anticipated expiration: 2040-01-08
Also published as: GB202000227D0; GB2590942B

Abstract

Disclosed is an air intake system 14 for use in an internal combustion engine 10. The intake system comprises a compressor unit 56 configured for receiving and compressing intake air to be guided into a combustion chamber of the engine 10; an air supply line 32 configured for selectively directing fresh air into the compressor unit 56; a bypass line configured for selectively directing fresh air from the air supply line 32 into an intake line 60 downstream of the compressor unit 56 and an exhaust gas recirculation line 44 configured for selectively directing exhaust gas of the engine into the compressor unit 56. The compressor unit 56 may be a supercharger and a separate turbocharger compressor 34 may be provided upstream of the compressor. A three-way valve (72) may be provided for controlling the flow of gas in the air supply line 32 and the EGR line 44 to the compressor 56. A control unit operating the system is also disclosed as is an internal combustion engine having the intake arrangement.

Description

Air intake system for use in an internal combustion engine Technical Field [0001] The present invention refers to an air intake system for an internal combustion engine and to an internal combustion engine which is equipped with such an air intake system.

Technological Background

[0002] For improving performance and efficiency of internal combustion engines, the use of turbocharger units is known which use engine's exhaust energy to compress air intake charge. In this way, more air and proportionally more fuel can be forced into a combustion chamber of the engine to provide greater charge density during combustion, thereby increasing power output and engine-operating efficiency.

[0003] However, upon combusting the charged air-fuel mixture, high temperatures in the combustion chamber may occur which affect emissions of the engine. Specifically, high combustion temperatures may cause the generation of nitrogen oxides (NO,.) which is a major driver of air pollution by contributing to, for example, the formation of smog and acid rain [0004] For avoiding such effects and thus for reducing the amount or quantity of nitrogen oxides in the exhaust gas of the engine, exhaust gas recirculation techniques are employed in internal combustion engines. According to these techniques, a portion of' the engine's exhaust gas is recirculated into the combustion chamber, thereby constituting a part of the air-fuel mixture to be combusted. In this way, the amount or quantity of gases inert to combustion is increased in the combustion chamber which act as absorbents of combustion heat, thereby reducing peak temperatures in the combustion chamber and thus the generation of nitrogen oxides.

100051 Due to the compressed air intake charge, the exhaust gas to be recirculated into the combustion chamber of a turbocharged engine needs to be elevated to a pressure level which is greater compared to a pressure prevailing in the air intake line. For doing so, the use of exhaust gas recirculating systems is known, in which exhaust gas to be recirculated into the combustion chamber is guided through a compressor or pump so as to be pressurized before being supplied into the air intake line.

10006] To that end, internal combustion engines are known which are further equipped with a supercharger to boost performance of the engine when being operated in a transient operating mode, during which engine load is substantially increased. Specifically, such supercharger are configured to support charge of intake air in a state, in which the performance of the turbocharger is not sufficient to compress the intake air to a demanded extent in order to reach a desired power output of the engine. For doing so, during the transient operating mode, intake air to be supplied into the combustion chamber is charged in subsequent steps, i.e. upon being subsequently guided through the turbocharger and the supercharger.

Summary of the invention

100071 Starting from the prior art, it is an objective to provide an improved air intake system for use in an internal combustion chamber which has a compact design and allows for implementing the above described engine functionalities, i.e. exhaust gas recirculation as well as supercharging intake air. To that end, it is a further objective to provide an internal combustion engine which is equipped with such an air intake system.

100081 These objectives are solved by the subject matter of independent claims. Preferred embodiments are set forth in the present specification, the Figures as well as the dependent claims.

100091 Accordingly, an air intake system for use in an internal combustion engine is provided which comprises a compressor unit configured for receiving and compressing intake air to be guided into a combustion chamber of the engine; an air supply line configured for selectively directing fresh air into the compressor unit, a bypass line configured for selectively directing fresh air from the air supply line into an intake line downstream of the compressor unit; and an exhaust gas recirculation line configured for selectively directing exhaust gas of the engine into the compressor unit.

[0010] Furthermore, an internal combustion engine is provided which is equipped with the above-described air intake system.

Brief description of the drawings

[0011] The present disclosure will be more readily appreciated by reference to the following detailed description when being considered in connection with the accompanying drawings in which: [0012] Figure 1 schematically shows an internal combustion engine which is equipped with an air intake system according to a first configuration; [0013] Figure 2 schematically shows the air intake system for use in the engine depicted in Fig. 1 according to a second configuration; [0014] Figure 3 schematically shows the air intake system for use in the engine depicted in Fig. 1 according to a third configuration; [0015] Figure 4 schematically shows the air intake system for use in the engine depicted in Fig. 1 according to a fourth configuration; and [0016] Figure 5 schematically shows the air intake system for use in the engine depicted in Fig. 1 according to a fifth configuration;

Detailed description of preferred embodiments

[0017] In the following, the invention will be explained in more detail with reference to the accompanying Figures. In the Figures, like elements are denoted by identical reference numerals and repeated description thereof may be omitted in order to avoid redundancies.

[0018] Fig. 1 schematically shows an internal combustion engine 10, also referred to as the 'engine' in the following, provided in the form of a reciprocating engine, such as a diesel engine, which is installed on a vehicle (not shown). The shown engine 10 comprises six cylinders 12, but is not limited to this application. In general, the engine 10 preferably comprises more than one cylinder, e.g. four, eight or more cylinders. Each cylinder 12 accommodates a piston which delimits a combustion chamber within the cylinder 12. The piston is configured for reciprocatingly moving within the cylinder 12 and is connected to a crankshaft of the engine 10 via a connecting rod. During operation of the engine 10, each one of the combustion chambers is supplied with an air-fuel mixture to be ignited therein so as to produce high-temperature and high-pressure gases which apply forces to and thus axially move the associated pistons, thereby rotating the crankshaft of the engine 10. In this way, chemical energy is transformed into mechanical energy. The air-fuel mixture to be supplied to and ignited in the combustion chamber is formed by mixing a fuel medium, i.e. diesel fuel, with intake air, including fresh or ambient air from outside the vehicle.

100191 For supplying the intake air into the combustion chambers, the engine 10 comprises an air intake system 14 which is connected to an intake manifold 16 of the engine 10 so as to guide intake air into the combustion chambers of each cylinder 12. Specifically, by means of the intake manifold 16, an intake air stream 18 provided by the air intake system 14 is split into separate intake air streams, each of which is guided to an associated one of the combustion chambers via separate flow passages of the intake manifold 16.

[0020] To that end, for supplying the fuel medium into the combustion chamber of each cylinder 12, a fuel injection valve or pump (not shown) is provided for variedly injecting the fuel medium into the combustion chamber so as to form the air-fuel mixture to be combusted.

[0021] Further, for expelling combustion gases from the combustion chambers, i.e. after combustion of the air-fuel mixture took place, the engine 10 comprises an exhaust system 20. Specifically, exhaust gases are separately expelled from the different combustion chambers and, by means of an outtake manifold 22, are merged to a common exhaust gas stream 24 which is guided into an exhaust gas line 26.

[0022] In the context of the present disclosure, the terms downstream" and "upstream" refer to a flow direction of gases within the engine 10, e.g. a flow direction of gases flowing through the air intake system 14 and the exhaust system 20.

[0023] The exhaust gas line 26 is provided with an exhaust gas treatment unit 28, particularly in the form of a particulate filter, which is configured to purify the exhaust gas, i.e. by removing particulates, such as soot.

[0024] The engine 10 is further equipped with a turbocharger unit 30 configured to use engine's exhaust energy of the exhaust gas stream 24 flowing through the exhaust gas line 26 to compress and thus to charge intake air flowing through the air supply line 32 of the air intake system 14. For doing so, the turbocharger unit 30 comprises a compressor 34 arranged in the air supply line 32. In this way, fresh air drawn into the air supply line 32 from the outside of the vehicle is passed through the compressor 34. The compressor 34 is mechanically coupled to a turbine 36 of the turbocharger unit 30 in a torque-transmitting manner via a shaft 38. The turbine 36 is arranged within the exhaust system 20 such that exhaust gas flowing through the exhaust gas line 26 is guided through the turbine 36.

[0025] By such a configuration, exhaust gas discharged from the cylinders 12 is expanded in the turbine 36 which rotatably actuates the turbine 36 together with the shaft 38 and the compressor 34. In other words, the turbine 36 is configured to convert energy of the exhaust gas into rotational movement of the shaft 38 so as to drive the compressor 34. In this way, upon rotatably driving the compressor 34, fresh air is drawn into the air supply line 32 and pressurized by the compressor 34 upon flowing through the air supply line 32. In other words, by driving the compressor 34, a fresh air stream 40 drawn into the air supply line 32 from outside the vehicle is directed into the compressor 34 which, after being guided through the compressor 34, constitutes a charged fresh air stream 41.

100261 Further, the engine 10 comprises an exhaust gas recirculation (EGR) system 42, also referred to as EGR loop, which is designed and configured to recirculate exhaust gas i e a part of the exhaust gas stream 24, flowing through the exhaust gas line 26 back into the combustion chambers of the engine 10. For doing so, the EGR system 42 comprises an EGR line 44 which branches off from the exhaust gas line 26 so as to guide an EGR stream 46 flowing through the EGR line 44 into the air supply line 32 of the air intake system 14. Upon flowing through the EGR line 44, the EGR stream 46 is guided through a cooler unit 55 for cooling the EGR stream 46 prior to being directed into the air supply line 32.

100271 As can be gathered from Fig. 1, the EGR line 44 may comprise at least one of a first junction passage 48, a second junction passage 50 and a third junction passage 52. The first junction passage 48 is designed to branch off from the exhaust gas line upstream of the turbine 36. The second junction passage 50 is designed to branch off from the exhaust gas line 26 downstream of the turbine 36 and upstream of the exhaust gas treatment unit 28. The third junction passage 52 is configured to branch of from the exhaust gas line 26 downstream of the exhaust gas treatment unit 28. For controlling and adjusting the amount and flow rate of exhaust gas guided into the EGR system 42 via the junction passages 4852, each one of the junction passages 48-52 is provided with a junction valve 54 for selectively directing exhaust gas therethrough.

100281 In the context of the present disclosure, the term "selectively directing" defines a characteristic of a component to control and regulate a flow rate of a fluid. Accordingly, such components are configured to selectively open and close a flow path of the fluid. To that end, such components may be configured to continuously or successively regulate a flow rate of the fluid between a maximum flow rate, e.g. associated to a fully opened flow path, and a minimum flow rate, e.g. associated to a closed flow path.

[0029] Specifically, in the shown configuration, the junction valves 54 may be provided in the form of a 2-way/2-position valve having an input port into which an upstream portion of the respective junction passage 48-52 opens and an output port into which a downstream portion of the respective junction passage 48-52 opens. Particularly, the junction valve 54 may be a proportional valve, i.e. which can be gradually or continuously shifted between an opened position and a closed position. In this way, the flow rate of exhaust gas flowing therethrough may be gradually or continuously adjusted between a maximum flow rate and a minimum flow rate.

100311 The basic structure and function of such an internal combustion engine 10 and its components are well known to a person skilled in the art and are thus not further specified. Rather, characteristics of the engine's air intake system 14 interlinked with the present invention are addressed and specified in the following.

100321 The air intake system 14 is configured to supply intake air into the combustion chambers of the engine 10 which, together with the fuel injected into the combustion chambers, forms the air-fuel mixture to be ignited. The intake air may include charged fresh air provided by the air supply line 32 and exhaust gas recirculated into the air supply line 32 by means of the EGR system 42. In dependence on an operating mode of the engine 10, the composition and characteristics, such as a pressure level, of intake air to be guided into the combustion chambers may differ. For example, in some operating modes, the intake air may consist of or mainly include charged fresh air. In other words, the intake air stream 18 directed into the intake manifold 16 of the engine 10 may be formed by the charged fresh air stream 41 or by merging the charged fresh air stream 41 and the EGR stream 46.

100331 The air intake system 14 comprises a compressor unit 56 configured for receiving and compressing intake air to be guided into the combustion chambers of the engine 10. Particularly, the compressor unit 56 is configured for receiving and compressing charged intake air, i.e, intake air charged upon being guided through the turbocharger unit 30.

100341 The compressor unit 56 comprises an inlet fluid-communicatively connected, particularly directly connected, to a compressor intake passage 58 of the air supply line 32. Specifically, the compressor intake passage 58 constitutes a downstream passage, i.e. a passage arranged at a downstream end of the air supply line 32. By such a configuration, the inlet of the compressor unit 56 is arranged downstream of the air supply line 32, i.e. its compressor intake passage 58.

[0035] Further, the compressor unit 56 comprises an outlet which is fluid-communicatively connected, particularly directly connected to an intake line 60 of the engine 10. The intake line 60 is arranged downstream of the compressor unit 56 and connects the outlet of the compressor unit 56 to the intake manifold 16 of the engine 10. In other words, the outlet of the compressor unit 58 is fluid-communicatively connected to the intake manifold 16 of the engine 10 via the intake line 60.

[0036] The compressor unit 56 may be provided in the form of any device suitable for compressing and pressurizing an intake air stream. Accordingly, such a device may also be referred to as a compressor, a pump or a charger, in particular a supercharger. Further, the compressor unit 56 may be electrically or mechanically driven.

[0037] In the shown configuration, the air supply line 32 is configured for selectively directing fresh air, i.e. at least a part of the charged fresh air stream 41, into the inlet of the compressor unit 56. More specifically, as set forth above, the air supply line 32 is fluid-communicatively connected to the turbocharger unit 30, i.e. its compressor 34, and configured to selectively Ode chortled air discharged from the turbocharger unit 30 into the compressor unit 56 [0038] For doing so, the air supply line 32 is provided with an air supply valve 62 for controlling and regulating the supply of fresh air into the compressor unit 56. Specifically, in the configuration depicted in Fig. 1, the air supply valve 62 is a 2-way/2-postion valve having an output port connected, i.e. directly connected to the compressor intake passage 58 of the air supply line 32 and an input port for receiving the charged fresh air stream 41, i.e. the fresh air stream 40 after being guided through the turbocharger unit 30. By such a configuration, the air supply valve 62 may be operated in an opened position, in which the charged fresh air stream 41 is directed into the compressor unit 56, and in a closed position, in which the charged fresh air stream 41 is prevented from being directed into the compressor unit 56. In other words, in the closed position, a flow path of the air supply valve 62 for guiding the charged fresh air stream 41 into the compressor intake passage 58 of the air supply line 32 is closed or shut off Accordingly, in the opened position, the flow path of the air supply valve 62 for guiding the charged fresh air stream 41 into the compressor intake passage 58 of the air supply line 42 is opened, thereby fluid-communicatively connecting the inlet of the compressor unit 56 to the turbocharger unit 30.

[0039] Particularly air supply valve 62 may be a proportional valve, i.e. which can be gradually or continuously shifted between its opened position and its closed position. In this way, the flow rate of the charged fresh air stream 41 through the air supply valve 62 may be gradually or continuously adjusted between a maximum flow rate and a minimum flow rate.

[0040] Further, the air intake system 14 comprises a bypass line 64 which is configured for selectively directing fresh air from the air supply line 32 into the intake line 60, i.e. downstream of the compressor unit 56. Particularly, the bypass line 64 is configured for selectively directing the charged fresh air stream 41 from the air supply line 32 into the intake line 60 downstream of the compressor unit 56, i.e. by bypassing the compressor unit 56. In other words, upon flowing through the bypass line 64, the fresh air to be guided into the combustion chambers of the engine 10 is prevented from being directed through the compressor unit 56.

[0041] For doing so, the bypass line 64 is configured to selectively receive fresh air from the air supply line 32 upstream of the compressor intake passage 58 of the air supply line 32. In other words, the bypass line 64 branches off from the air supply line 32 upstream of the compressor intake passage 58.

Specifically, in the configuration depicted in Fig. 1, the air intake system 14 is provided such that the bypass line 64 is configured to selectively receive fresh air from the air supply line 32 upstream of the air supply valve 62, i.e. before the fresh air enters the supply valve 62. Accordingly, the bypass line 64 branches off from the air supply line 32 upstream of the bypass valve 62.

[0042] The bypass line 64 is provided with a bypass valve 66 configured for controlling a supply of fresh air to be guided into the intake line 60 upon flowing through the bypass line 64. Specifically, in the configuration depicted in Fig. 1, the bypass valve 66 is a 2-way/2-position valve having an input port for receiving charged fresh air directed into the bypass line 64 and an output port for directing the received charged fresh air into the intake line 60. The bypass valve 66 may be operated in an opened position, in which the charged fresh air stream 41, at least a part thereof; is directed into the intake line 60 upon flowing through the bypass line 64, and in a dosed position, in which the charged fresh air stream 41 is prevented from being directed through the bypass line 64. In other words, in the closed position, a flow path of the bypass valve 66 for guiding the charged fresh air stream 41 through the bypass line 64 is closed or shut off. Accordingly, in the opened position, the flow path of the bypass valve 66 for guiding the charged fresh air stream 41, i.e. at least a part thereof, into the intake line 64 is opened.

[0043] Particularly the bypass valve 66 may be a proportional valve, i.e. which can be gradually or continuously shifted between its opened position arid its closed position. In this way, the flow rate of the charged fresh air stream 41 through the bypass valve 66 may be gradually or continuously adjusted between a maximum flow rate and a minimum flow rate.

[0044] As set forth above, the EGR system 42 comprises the FOR line 44 which constitutes a part of the proposed air intake system 14. Specifically, in the proposed air intake system 14, the EGR line 44 is configured for selectively directing exhaust gas from the exhaust system 20 of the engine 10 into the inlet of the compressor unit 56. For doing so, the FOR line 44 comprises an exhaust

-II-

valve 68 which is configured for controlling and regulating the supply of exhaust gas into and through the compressor unit 56.

[0045] Specifically, in the configuration depicted in Fig. 1, the exhaust valve 68 is a 2-way/2-position valve having an input port for receiving exhaust gas from the exhaust system 20 of the engine 10 and an output port for directing the received exhaust gas into the air supply line 32, i.e. its compressor intake passage 58.

[0046] By such a configuration, the exhaust valve 68 may be operated in an opened position, in which the EGR stream 46 is directed into the air supply line 32, and in a closed position, in which the EGR stream 46 is prevented from being directed into the air supply line 32. In other words, in the closed position, a flow path of the exhaust valve 68 for guiding the EGA stream 46 into the air supply line 32 is closed or shut off. Accordingly, in the opened position, the flow path of the exhaust valve 68 for guiding the EGR stream 46 into the air supply line 32 is opened.

[0047] Particularly exhaust valve 68 may be a proportional valve, i.e. which can be gradually or continuously shifted between its opened position and its closed position. In this way, the flow rate of the charged fresh air stream 41 through the exhaust valve 68 may be gradually or continuously adjusted between a maximum flow rate and a minimum flow rate.

[0048] As set forth above, the EGR line 44 is equipped with at least one of the first to third junction passages 48-52. Specifically, when being provided with the first junction passage 48, the EGR line 44 may be configured to selectively receive exhaust gas from the exhaust system 20 upstream of the turbine 36 of the turbocharger unit 30 and to guide the thus received exhaust gas into the compressor unit 56. Accordingly, when being provided with the second junction passage 50, the EGR line 44 may be configured to selectively receive exhaust gas from the exhaust system 20 downstream of the turbocharger unit 30 and upstream of the exhaust gas treatment unit 28 and to guide the thus received exhaust gas into the compressor unit 56. To that end, when being provided with the third junction passage 52, the EGR line 44 may be configured to selectively receive exhaust gas from the exhaust system 20 downstream of the exhaust gas treatment unit 28 and to guide the thus received exhaust gas through the compressor unit 56.

[0049] In a further development, the function of the exhaust valve 68 may be allocated to the at least one junction valve 54. Thus, in such a configuration, the exhaust valve 68 may be omitted. Accordingly, the above described configuration and operating modes of the exhaust valve 68 may also apply to the at least one junction valve 54. Further, in an alternative configuration, in which the engine 10 comprises only one of the first to third junction passages 48, 50 and 52, the junction valve 54 may be omitted. Accordingly, in such a configuration, the function of the junction valve 54 may be allocated to the exhaust valve 68.

[0050] The air intake system 14 further comprises a control unit (not shown) which may be a part of an electronic control unit of the engine 10 or which may be provided separately therefrom. The control unit is configured to control operation of the air intake system 14 and its components, i.e. its valves. Specifically, in the configuration depicted in Fig. 1, the control unit is configured for controlling operation of and thus actuate the junction valves 54, the air supply valve 62, the bypass valve 66 and the exhaust valve 68. For example, these valves 54, 62, 66, 68 may be electrically or mechanically, e.g. hydraulically, actuated by the control unit.

[0051] The control unit is configured to operate the air intake system 14 in different operating modes. Specifically the control unit is configured to operate the air intake system 14 in a transient operating mode, also referred to as a transition operating mode. In the context of the present disclosure, the term "transient operating mode" refers to an operating mode of the engine 10 during which engine power or load is increased and/or during which engine speed is accelerated. Thus, during the transient operating mode, the output torque and/or rotational speed of the engine 10 are/is increased. In other words, by being operated in the transient operating mode, the engine 10 is transitioned from a first operating state to a second operating state, wherein in the second operating state, the engine 10 is operated at higher load and/or at higher engine speed compared to the first operating state 100521 Further, the control unit is configured to operate the air intake system 14 in a non-transient operating mode, also referred to as a normal operating mode. In the context of the present disclosure, the term "non-transient operating mode" refers to an operating mode of the engine 10 during which engine power and/or engine speed and/or engine torque are/is maintained at a substantially constant level.

100531 More specifically, when being operated in the transient operating mode, the air intake system 14 is configured to direct fresh air into the inlet of the compressor unit 56, to reduce or stop the supply of exhaust gas through the EGR line 44 to be directed into the inlet of the compressor unit 56 and to reduce or stop the supply of fresh air through the bypass line 64 to be directed into the intake line 60. Accordingly, in the transient operating mode, the control unit may operate the air supply valve 62 in its opened position, the bypass valve 66 in its closed position and the exhaust valve 68 in its closed position. In this operating mode, fresh air, upon flowing through the air supply line 32, is subsequently guided through the compressor 34, the air supply valve 62, the compressor intake passage 58 and the compressor unit 56 before being directed into the intake line 60. In this way, the fresh air stream 40 is charged in two steps before being directed into the intake line 60. Specifically, the fresh air stream 40 is charged, at first, in compressor 34, which constitutes a first step, and thereafter in the compressor unit 56, which constitutes a second step.

100541 To that end, when being operated in the non-transient operating mode, the air intake system 14 is configured to stop or reduce the supply of fresh air through the air supply line 32 to be directed into the inlet of the compressor unit 56, to direct fresh air flowing through the bypass line 64 from the air supply line 32 into the intake line 60, and to direct exhaust gas flowing through the EGR line 44 into the inlet of the compressor unit 56. Accordingly, in the non-transient operating mode, the control unit may operate the air supply valve 62 in its closed position, the bypass valve 66 in its opened position, the exhaust valve 68 in its opened position and at least one of the junction valves 54 in its opened position. Thus, when operating the air intake system 14 in the non-transient operating mode, the EGR stream 46 is guided through and thus charged in the compressor unit 56 before being directed into the intake line 60. Further, the charged fresh air stream 41 is guided through the bypass line 64 before being discharged into the intake line 60, thereby bypassing the compressor unit 56. In this way, the charged EGR stream 46 and the charged fresh air stream 41 are merged in the intake line 60 before being directed into the combustion chambers of the engine 10.

[0055] The structural configuration of the proposed air intake system 14 allows that the compressor unit 56 serves for both charging the EGR stream 46, i.e. when the air intake system 14 is operated in the non-transient operating mode, and further charging, i.e. supercharging, the charged fresh air stream 41 when the air intake system 14 is operated in the transient operating mode. Compared to known configurations, in which the EGR stream and the charged intake air stream are pressurized or compressed with different and separately provided compression units, the proposed air intake system may contribute to a cost-, space-and weight-efficient design of the engine 10.

[0056] Fig. 2 schematically shows the air intake system 14 according to a second configuration which is intended to be used in the engine 10 depicted in Fig. 1. Compared to the configuration depicted in Fig. 1, the air intake system 14 according to the second configuration comprises a 3-way valve 70 which replaces the air supply valve 62 and the bypass valve 66 employed in the first configuration of the air intake system. In other words, the 3-way valve 70 constitutes a valve which provides for the functionality of the air supply valve 62 and the bypass valve 66. In this way, the 3-way valve 70 constitutes the air supply valve 62 and the bypass valve 66.

[0057] The 3-way valve 70 comprises an input port which is arranged in the air supply line 32 so as to receive the charged fresh air stream 41. Further, the 3-way valve 70 comprises a first output port connected, i.e. directly connected, to an upstream end of the compressor intake passage 58 of the air supply line 32 and a second output port connected, i.e. directly connected to an upstream end of the bypass line 64.

100581 Specifically, the 3-way valve 70 is provided as a 3-way/2-position valve, i.e. which can be actuated into a first position and into a second position. When being operated in the first position, the input port is fluid-communicatively connected to the first output port of the 3-way valve 70, while a connection between the input port and the second output port is interrupted. When being operated in the second position, the input port is connected to the second output port of the 3-way valve 70, while a connection between the input port and the first output port is interrupted. Particularly, the 3-way valve 70 may be a proportional control valve, i.e. which can be gradually or continuously shifted between its two positions so as to gradually or continuously adjust of flow rate of gas flowing therethrough.

[0059] In this configuration, the control unit is configured to operate the 3-way valve 70 in its first position during the transient operating mode of the air intake system 14 and to operate the 3-way valve 70 into its second position during the non-transient operating mode of the air intake system N. [0060] Fig. 3 schematically shows the air intake system 14 according to a third configuration which is intended to be used in the engine 10 depicted in Fig. I. Compared to the configuration depicted in Fig. 2, the air intake system 14 according to the third configuration comprises a further 3-way valve 72 which replaces the exhaust valve 68 employed in the second configuration. In other words, the further 3-way valve 72 constitutes a valve which provides for the functionality of the exhaust valve 68. Thus, in this configuration, the further 3-way valve 72 constitutes the exhaust valve 68.

[0061] As can be gathered from Fig. 3, the further 3-way valve 72 is arranged in the compressor intake passage 58 of the air supply line 32 and comprises a first input port arranged in the compressor intake passage 58 so as to receive the charged fresh air stream 41 and a second input port arranged at a downstream end of the EGR line 44 as to receive the EGR stream 44. Further, the 3-way valve 70 comprises an output port arranged in the compressor intake passage 58 so as to direct the received gas stream into the inlet of the compressor unit 56.

100621 Specifically, the further 3-way valve 72 is provided as a 3-way/2-position valve, i.e. which can be actuated into a first position and into a second position. When being operated in the first position, the first input port is connected to the output port of the further 3-way valve 72, while a connection between the second input port and the output port is interrupted. When being operated in the second position, the second input port is connected to the output port of the further 3-way valve 72, while a connection between the first input port and the output port is interrupted.

100631 In this configuration, the control unit is configured to operate the further 3-way valve 72 in its first position during the transient operating mode of the air intake system 14 and to operate the further 3-way valve 72 into its second position during the non-transient operating mode of the air intake system 14.

[0064] Particularly, the further 3-way valve 72 may be a proportional control valve, i.e. which can be gradually or continuously shifted between its two positions so as to gradually or continuously adjust of flow rate of gas flowing therethrough.

[00651 Fig. 4 schematically shows the air intake system 14 according to a fourth configuration which is intended to be used in the engine 10 depicted in Fig. 1. Compared to the configuration depicted in Fig. 1, the air intake system 14 according to the fourth configuration comprises the above described further 3-way valve 72, i.e. described in connection with the third configuration, which replaces the air supply valve 62 and the exhaust valve 68 employed in the first configuration. In other words, the further 3-way valve 72 constitutes a valve which provides for the functionality of the air supply valve 62 and the exhaust valve 68. In this way, the 3-way valve 70 constitutes the air supply valve 62 and the exhaust valve 68. The further 3-way valve 72 is actuated by the control unit as described in connection with the third configuration.

[0066] Fig. 5 schematically shows the air intake system 14 according to a fifth configuration which is intended to be used in the engine 10 depicted in Fig. 1. Compared to the configuration depicted in Fig. 4, in the air intake system 14 according to the fifth configuration, the bypass valve 66 is provided in the form of a check valve configured for allowing charged fresh air to be guided therethrough from the air supply line 32 into the intake line 60, while a flow therethrough from the intake line 60 into the air supply line 32 is prevented.

[0067] It will be obvious for a person skilled in the art that these embodiments and items only depict examples of a plurality of possibilities. Hence, the embodiments shown here should not be understood to form a limitation of these features and configurations. Any possible combination and configuration of the described features can be chosen according to the scope of the invention.

[0068] This is particularly the case with respect to the following optional features which may be combined with some or all embodiments, items and/or features mentioned before in any technically feasible combination.

[0069] An air intake system for use in an internal combustion engine may be provided. The air intake system may comprise a compressor unit configured for receiving and compressing intake air to be guided into a combustion chamber of the engine; an air supply line configured for selectively directing fresh air into the compressor unit; a bypass line configured for selectively directing fresh air from the air supply line into an intake line downstream of the compressor unit; and an exhaust gas recirculation line configured for selectively directing exhaust gas of the engine into the compressor unit.

[0070] The proposed configuration of the air intake system enables that the compressor unit is configured to compress both the fresh air provided by the air supply line and the exhaust gas provided by the exhaust gas recirculation line. Compared to known configurations, in which two separate compressor units are used to compress the fresh air provided by an air supply line and the exhaust gas provided by an exhaust gas recirculation line, the proposed solution contributes to a compact and efficient design of the air intake system.

[0071] The proposed air intake system may be employed in any suitable internal combustion engine, such as a reciprocating engine, in particular a diesel engine. For example, such internal combustion engines may be utilized or be installed in vehicles, such as vessels, or power plants, i.e. as main or auxiliary engines.

[0072] The compressor unit of the air intake system may comprise an inlet which is fluid-communicatively connected to the air supply line. Specifically, the air supply line may open into the inlet of the compressor unit. Further, the compressor unit may comprise an outlet which is fluid-communicatively connected to the intake line. Specifically, the output of the compressor unit may be directly connected to the intake line. In an installed state of the air intake system, in which the air intake system is installed in the engine, the outlet of the compressor unit may be fluid-communicatively connected to an intake manifold of the engine via the intake line.

[0073] The proposed air intake system may be employed in an engine which comprises a turbocharger unit configured for charging intake air. Accordingly, the air supply line of the proposed air intake system may be fluid-communicatively connected to the turbocharger unit, in particular a compressor thereof. For example, the turbocharger unit may be a multi-stage turbocharger unit. Accordingly, the air supply line may be configured for selectively guiding charged fresh air i.e. discharged from the turbocharger unit, into the compressor unit.

[0074] For being suitable for selectively directing fresh air into the compressor unit, the air supply line may comprise an air supply valve configured for controlling a supply of fresh air into the compressor unit. Specifically, the air supply valve may be provided or constituted by a shut-off-valve, particularly a proportional valve. Alternatively or additionally, the air supply valve may be provided or constituted by a 2-way valve or a 3-way valve, particularly a proportional valve, or any other suitable valve configuration. For example, the air supply valve may be provided or constituted by a 3-way/2-position valve.

100751 Further, the air supply line may comprise a compressor intake passage for fluid-communicatively connecting the air supply valve to the inlet of the compressor unit. Accordingly, the compressor intake passage may constitute a downstream end section of the air supply line.

100761 As set forth above, the bypass line is configured for selectively directing fresh air from the air supply line into the intake line, particularly by bypassing the compressor unit. Specifically, the bypass line may be configured for selectively receiving fresh air from the air supply line upstream of the compressor intake passage and guiding the received fresh air into the intake line, particularly downstream of the compressor unit.

100771 For being suitable for selectively directing fresh air into the intake line, the bypass line may comprise a bypass valve configured for controlling the supply of fresh air to be guided into the intake line upon flowing through the bypass line. Specifically, the bypass valve may be provided in the form of a shutoff valve, in particular a proportional valve for selectively guiding and adjusting a flow of fresh air through the bypass line. Alternatively, the bypass valve may be provided in the form of a check valve configured for allowing fresh air to be guided therethrough in direction from the air supply line to the intake line.

100781 Alternatively or additionally, the bypass valve may be provided or constituted by a 2-way valve or a 3-way valve or any other suitable valve configuration. For example, the bypass valve may be provided or constituted by a 3-way/2-position valve. In a further development, the air intake system may comprise a 3-way valve which constitutes both the air supply valve and the bypass valve. For example, the air supply line may be provided with a 3-way valve configured for selectively guiding fresh air flowing through the supply line into the compressor unit or into the bypass line.

100791 As set forth above, the exhaust gas recirculation line is configured for selectively directing exhaust gas of the engine into the compressor unit. For doing so, the exhaust gas recirculation line may comprise an exhaust valve configured for controlling and adjusting the supply of exhaust gas into the compressor unit. Specifically, the exhaust valve may be provided in the form of a shut-off valve, in particular a proportional valve, for selectively guiding and adjusting a flow of exhaust gas through the exhaust gas recirculation line.

100801 Alternatively or additionally, the exhaust valve may be provided or constituted by a 2-way valve or a 3-way valve or any other suitable valve configuration. For example, the exhaust valve may be provided or constituted by a 3-way/2-position valve. In a further development, the air intake system may comprise a further 3-way valve which constitutes both the air supply valve and the exhaust valve. For example, the air supply line may be provided with a 3-way valve which is configured for selectively guiding fresh air flowing through the supply line or exhaust gas flowing through the exhaust gas recirculation line into the compressor unit.

[0081] The exhaust gas recirculation line is preferably provided such that it is fluid-communicatively connected to the exhaust system of the engine, i.e, an exhaust gas line. For doing so, the exhaust gas recirculation line may be designed and configured for selectively receiving exhaust gas from the exhaust system upstream of a turbine of the turbocharger unit and to selectively guide the thus received exhaust gas into the compressor unit. Alternatively or additionally, the exhaust gas recirculation line may be designed and configured for selectively receiving exhaust gas from the exhaust system downstream of the turbocharger unit and upstream of an exhaust gas treatment unit, in particular a particulate filter, and to guide the thus received exhaust gas into the compressor unit. Alternatively or additionally, the exhaust gas recirculation line may be designed and configured for selectively receiving exhaust gas from the exhaust system downstream of the exhaust gas treatment unit and to guide the received exhaust gas into the compressor unit.

100821 In a further development, the air intake system may further comprise a control unit configured to operate the air intake system in a transient operating mode, in which the air intake system may be configured to direct fresh air flowing through the air supply line into the compressor unit, to reduce or stop the supply of exhaust gas through the exhaust gas circulation line to be directed into the inlet of the compressor unit and to reduce or stop the supply of fresh air through the bypass line to be directed into the intake line. For example, the air intake system may be configured to prevent the exhaust gas circulation line from guiding exhaust gas into the compressor unit and to prevent the bypass line from directing fresh air from the air supply line into the intake line. In this way, in the transient operating mode, the air intake system may employ the engine functionality of supercharging the intake air.

100831 Further the control unit may be configured to operate the air intake system in a non-transient operating mode, in which the air intake system may be configured to reduce or stop the supply of fresh air through the air supply line to be directed into the compressor unit, to direct fresh air flowing through the bypass line into the intake line, and to direct exhaust gas flowing through the exhaust gas recirculation line into the compressor unit. For example, the air intake system may be configured to prevent the air supply line from directing fresh air into the compressor unit In this way, in the non-transient operating mode, the air intake system may employ exhaust gas recirculation.

[0084] Furthermore, an internal combustion engine, in particular a reciprocating engine, may be provided which is equipped with an intake system as specified above Accordingly, technical features which are described in connection with the above air intake system may also relate and be applied to the proposed internal combustion engine, and vice versa.

Industrial Applicability

100851 With reference to the Figures, an air intake system for use in an internal combustion engine and an internal combustion engine which is equipped with such an air intake system are suggested. The suggested air intake system as described above is applicable in any suitable internal combustion engine. Further, the suggested air intake system, may replace conventional air intake systems and may serve as a replacement or retrofit part.

List of reference numerals engine 12 cylinder 14 air intake system 16 intake manifold 18 intake air stream exhaust system 22 outtake manifold 24 exhaust gas stream 26 exhaust gas line 28 exhaust gas treatment unit turbocharger unit 32 air supply line 34 compressor 36 turbine 38 shaft fresh air stream 41 charged fresh air stream 42 exhaust gas recirculation (EGR) system 44 exhaust gas recirculation (EGR) line 46 exhaust gas recirculation (EGR) stream 48 first to third junction passage second junction passage 52 third junction passage 54 junction valve cooler unit 56 compressor unit 58 compressor intake passage intake line 62 air supply valve 64 bypass line 66 bypass valve 68 exhaust valve 3-way valve 72 further 3-way valve

Claims

Claims What is claimed is: 1. Air intake system (14) for use in an internal combustion engine (10), comprising: - a compressor unit (56) configured for receiving and compressing intake air to be guided into a combustion chamber of the engine (10); - an air supply line (32) configured for selectively directing fresh air into the compressor unit (56); - a bypass line (64) configured for selectively directing fresh air from the air supply line (32) into an intake line (60) downstream of the compressor unit (56); and - an exhaust gas recirculation line (44) configured for selectively directing exhaust gas of the engine into the compressor unit (56).
2. Air intake system according to claim 1, wherein the compressor unit (56) comprises an outlet which, in an installed state of the air intake system (14) in the engine (10), is fluid-communicatively connected to an intake manifold (16) of the engine (16) via the intake line (60).
3. Air intake system according to claim 1 or 2, wherein the air supply line (32) is fluid-communicatively connected to a turbocharger unit (30) and configured for selectively guiding charged fresh air discharged from the turbocharger unit (30) into the compressor unit (56).
4. Air intake system according to any one of claims 1 to 3, wherein the air supply line (32) comprises an air supply valve (62, 70, 72) configured for controlling a supply of fresh air into the compressor unit (56).
5. Air intake system according to any one of claims Ito 4, wherein the air supply line (32) comprises a compressor intake passage (58) for fluid-communicatively connecting the air supply valve (62) to the compressor unit (56), and wherein the bypass line (64) is configured for selectively receiving fresh air from the air supply line (32) upstream of the compressor intake passage (58) and guiding the received fresh air into the intake line (32).
6. Air intake system according to any one of claims 1 to 5, wherein the bypass line (64) comprises a bypass valve (66; 70) configured for controlling the supply of fresh air to be guided into the intake line (60) upon flowing through the bypass line (64).
7. Air intake system according to claim 6, wherein the bypass valve (66) is provided in the form of a check valve configured for allowing fresh air to be guided therethrough in direction from the air supply line (32) to the intake line (60).
8. Air intake system according to any one of claims 1 to 7, wherein the air supply line (32) comprises a 3-way valve (70) which is configured for selectively guiding fresh air flowing through the supply line (32) into the compressor unit (56) or into the bypass line (64).
9. Air intake system according to any one of claims 1 to 8, wherein the exhaust gas recirculation line (44) comprises an exhaust valve (68, 72) configured for controlling the supply of exhaust gas into the compressor unit (56).
10. Air intake system according to any one of claims 1 to 9, wherein the air supply line (32) comprises a further 3-way valve (72) which is configured for selectively guiding fresh air flowing through the supply line (32) or exhaust gas flowing through the exhaust gas recirculation line (44) into the compressor unit (56).
11 Air intake system according to any one of claims 1 to 10, wherein the exhaust gas recirculation line (44) is fluid-communicatively connected to an exhaust system (20) of the engine (10) and configured for selectively receiving exhaust gas from the exhaust system (20) upstream of a turbine (36) of the turbocharger unit (30).
12. Air intake system according to any one of claims 1 to 11, wherein the exhaust gas recirculation line (44) is configured for selectively receiving exhaust gas from the exhaust system (20) downstream of the turbocharger unit (30) and upstream of an exhaust gas treatment unit (28).
13. Air intake system according to any one of claims 1 to 12, wherein the exhaust gas recirculation line (44) is configured for selectively receiving exhaust gas from the exhaust system (20) downstream of the exhaust gas treatment unit (28).
14. Air intake system according to any one of claims 1 to 13, further comprising a control unit configured to operate the air intake system (14) -in a transient operating mode, in which the air intake system (14) is configured to direct fresh air flowing through the air supply line (32) into the compressor unit (56), to reduce or stop a supply of exhaust gas through the exhaust gas circulation line (44) to be directed into the inlet of the compressor unit (56) and to reduce or stop a supply of fresh air through the bypass line (64) to be directed from the air supply line (32) into the intake line (60); and -in a non-transient operating mode, in which the air intake system (14) is configured to reduce or stop the supply of fresh air through the air supply line (32) to be directed into the compressor unit (56), to direct fresh air flowing through the bypass line (64) into the intake line (60), and to direct exhaust gas flowing through the exhaust gas recirculation line (44) into the compressor unit (56).

15, Internal combustion engine (10), comprising an air intake system (14) according to any one of claims 1 to 14.