WO2014207501A1

WO2014207501A1 - Air intake system

Info

Publication number: WO2014207501A1
Application number: PCT/IB2013/001691
Authority: WO
Inventors: Bertrand Cauvin; Fabien Lacroix
Original assignee: Renault Trucks
Priority date: 2013-06-24
Filing date: 2013-06-24
Publication date: 2014-12-31

Abstract

The present disclosure relates to an air intake system (12) for an internal combustion engine (10). The air intake system (12) comprises an air inlet (14), a first outlet set (16) comprising at least one first outlet (18, 20, 22), a second outlet set (24) comprising at least one second outlet (26, 28, 30), at least one exhaust gas recirculation inlet (32, 34) and an internal wall assembly (36) comprising at least one wall (38) for distributing recirculated exhaust gases from the exhaust gas recirculation inlet (32, 34) towards the outlets (18, 20, 22). According to the present disclosure, the internal wall assembly (36) delimits a first conduit portion (40) for conveying air to the first outlet set (16) and a second conduit portion (42) for conveying air to the second outlet set (24). Moreover, the internal wall assembly (36) is positioned in relation to the at least one exhaust gas recirculation inlet (32, 34) for distributing recirculated exhaust gases from the inlet (32, 34) towards the outlets (18, 20, 22, 26, 28, 30) via both the first conduit portion (40) and the second conduit portion (42).

Description

AIR INTAKE SYSTEM

TECHNICAL FIELD

The present disclosure relates to an air intake system according to the preamble of claim 1. Moreover, the present disclosure relates to an internal combustion engine. Further, the present disclosure relates to a vehicle.

BACKGROUND

An internal combustion engine of today may comprise an exhaust gas recirculation arrangement, also referred to as an EGR arrangement, in order to reduce nitrogen oxide emissions from the internal combustion engine. With an EGR arrangement, at least a portion of the amount of exhaust gases produced by the internal combustion engine is discharged into an air intake system of the internal combustion engine.

An example of an air intake system to which an EGR inlet is connected is presented in US 6,945,238. The air intake system comprises a conduit defining a passageway that conveys air to a manifold. An EGR inlet in the conduit enables EGR to mix with the air. A plate is sufficiently positioned in the passageway such that air in the passageway is divided into two streams, one stream on each side of the plate. The plate is positioned with respect to the EGR inlet such that a greater part of the EGR entering the passageway is diverted to flow only on one side of the plate. However, there is a risk that the air intake system disclosed in US 6,945,238 does not sufficiently mix the recirculated exhaust gas with the intake air.

SUMMARY

One object of the present disclosure is to provide an air intake system for an internal combustion engine in which recirculated exhaust gases and inlet air may be appropriately mixed before the mix reaches the outlets of the air intake system.

This object is achieved by an air intake system according to claim 1. As such, the present disclosure relates to an air intake system for an internal combustion engine. The air intake system comprises an air inlet, a first outlet set comprising at least one first outlet, a second outlet set comprising at least one second outlet, at least one exhaust gas recirculation inlet and an internal wall assembly comprising at least one wall for distributing recirculated exhaust gases from the exhaust gas recirculation inlet towards the outlets.

According to the present disclosure, the internal wall assembly delimits a first conduit portion for conveying air to the first outlet set and a second conduit portion for conveying air to the second outlet set. Moreover, the internal wall assembly is positioned in relation to the at least one exhaust gas recirculation inlet for distributing recirculated exhaust gases from the exhaust gas recirculation inlet towards the outlets via both the first conduit portion and the second conduit portion.

The internal wall assembly is preferably formed by a continuous wall, or plate. The internal wall assembly preferably has a height at least substantially commensurate with a height of the corresponding internal height of the air conduit in question. An air intake system according to the above implies that an appropriate mix of recirculated exhaust gases and intake air may be provided to the cylinders connected to the air intake system. Moreover, by virtue of the fact that the recirculated exhaust gas is distributed to both the first and second conduit portions, an appropriate mix may be obtained for a plurality of the cylinders connected to the air intake system.

Optionally, the first outlet of the first outlet set and the second outlet of the second outlet set are located at a lateral distance from one another along a lateral direction, at least a portion of the internal wall assembly being located between the first outlet and the second outlet in the lateral direction.

The above position of at least a portion of the internal wall assembly creates conditions for deflection at least a portion of the intake air at, or at least close to, the internal wall assembly. More specifically, the internal wall assembly may be designed for dividing the incoming air in two streams, one stream on each side of the internal wall assembly. The interna! wall assembly is preferably configured for directing a first of said streams towards the first outlet set and a second of said streams towards the second outlet set. Such a direction change may in turn result in a more turbulent air flow which in turn may improve the mix of gases. Optionally, the air intake system has an intended flow direction from the air inlet towards the first and second outlet sets, the internal wall assembly comprising an upstream portion located closest to the air inlet, the air intake system comprising a first exhaust gas recirculation inlet located in the first conduit portion and a second exhaust gas recirculation inlet located in the second conduit portion, each one of the first and second exhaust gas recirculation inlets being located at least partially downstream of the upstream portion.

The above position of the exhaust gas recirculation inlets implies that the recirculated exhaust gas is fed to the first conduit portion and the second conduit portion when the intake air flow has already been divided by the internal wall assembly. This in turn implies that the intake air flow will be, at least to some extent, turbulent when it is mixed with the recirculated exhaust gas. This in turns implies that an appropriate mix of the gases may be obtained.

Optionally, the internal wall assembly extends at least partially from the air inlet to the first and second outlet set.

Optionally, the air intake system extends in a longitudinal direction, a height direction and a lateral direction, the height and lateral directions forming an extension plane, wherein an intended flow direction from the air inlet towards the upstream portion of the internal wall assembly comprises a flow direction component that extends in the extension plane.

Optionally, the internal wall assembly comprises a first internal wall assembly portion extending from the upstream portion along a first wall axis in the extension plane. The internal wall assembly further comprises a second internal wall assembly portion extending from the first internal wall assembly portion along a second wall axis in the extension plane. The first and second axes form a first angle of at least 45°. Preferably, the second internal wall assembly portion extends from a downstream portion of the first interna! wall assembly portion and especially from an end of the first internal wall assembly portion opposite the upstream portion. Preferably, the first internal wall assembly portion and the second internal wall assembly portion form a continuous wall section. The above discussed lower limit for the direction change from the first internal wall assembly portion to the second internal wall assembly portion implies that the intake air will change its direction when flowing towards at least some of the outlets. Such a direction change may improve the mix of gases.

Optionally, the internal wall assembly comprises a third internal wall assembly portion extending from the second internal wall assembly portion along a third wall axis in the extension plane. The second and third axes form a second angle of at least 30° so that the air is deflected further in the same direction (clockwise or counterclockwise) as achieved via the curvature achieved via the first and second internal wall assembly portions. Preferably, the internal wall assembly forms a J- or U-shape or similar in cross section. Preferably, the third internal wall assembly portion extends from a downstream portion of the second internal wall assembly portion and especially from an end of the second internal wall assembly portion opposite the first internal wall assembly portion. Preferably, the second internal wall assembly portion and the third internal wall assembly portion form a continuous wall section. More preferably, the first, second and third internal wall assembly portions form a continuous wall.

By virtue of the direction change from the second internal wall assembly portion to the third internal wall assembly portion, it may be possible to increase the intake air flow direction change, and thus the gas mixing possibilities, further.

Optionally, the first axis has a first axis lateral component and the third axis has a third axis lateral component, the first and third axis lateral components extending in opposite directions.

A configuration according to the above implies that at least a component of the intake air flow changes directions on its way through the air intake system. This may in turn increase the possibility to increase the turbulence, and thus the gas mixing capabilities.

Optionally, the first wall direction is substantially parallel to the lateral direction.

Optionally, the second internal wall assembly portion is located between the first outlet set and the second outlet set in the lateral direction. Optionally, the air intake system is adapted to discharge fluid from the first outlet set in an outlet direction that is substantially parallel to the longitudinal direction.

Optionally, each one of the first and second exhaust gas recirculation inlets is oriented such that exhaust gas is discharged into the air intake system in a discharge direction that is substantially parallel to the longitudinal direction.

By virtue of exhaust gas inlets that are adapted to discharge recirculated exhaust gas in a direction that is parallel to the longitudinal direction, it may be possible to discharge the recirculated exhaust gas in a direction that is substantially perpendicular to the flow direction of the intake air. This in turn implies a possibility to obtain an improved gas mix.

Optionally, each one of the first and second conduit portions are adapted to be permanently open. As such, the air intake system preferably does not comprise any valves or hatches that are adapted to close either one of the first or second conduit portions.

Optionally, the upstream portion has an upstream portion thickness in the extension plane and an adjacent portion of the internal wall assembly has an adjacent portion thickness, the upstream portion thickness being at least two times greater than the adjacent portion thickness.

By virtue of the fact that the upstream portion thickness is greater that the thickness of an adjacent portion of the internal wall assembly, it is possible to increase the level of turbulence of the intake air flow that passes the internal wall assembly. Moreover, in the event that a negative pressure is obtained at one or more of the outlets, the thicker upstream portion may prevent a negative gas flow propagating from one or more of the outlets towards the air inlet. Optionally, the air intake system comprises an inlet manifold portion and an air conduit portion and wherein the air conduit portion comprises the air inlet.

Optionally, the at least one exhaust gas recirculation inlet is positioned at a junction between the inlet manifold portion and the air conduit portion. Optionally, a junction between the inlet manifold portion and the air conduit portion is positioned between the first and second outlet sets in a direction defined by the outlets of at least one of the sets of outlets. A second aspect of the present disclosure relates to an internal combustion engine comprising an air intake system according to any one of the preceding claims.

A third aspect of the present disclosure relates to a vehicle comprising an internal combustion engine according to the second aspect of the present disclosure and/or an air intake system according to the first aspect of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to the appended drawings, below follows a more detailed description embodiments of the invention cited as examples.

In the drawings:

Fig. 1 illustrates a truck comprising an internal combustion engine; Fig. 2 illustrates a cross-sectional perspective view of an embodiment of an air intake system;

Fig. 3 illustrates a cross-sectional view of a portion of the Fig. 2 air intake system; Fig. 4 is a rear side view of a portion of the Fig. 2 embodiment;

Fig. 5 is a front side view of a portion of the Fig. 2 embodiment, and

Fig. 6 illustrates a perspective view of the Fig. 2 embodiment.

It should be noted that the appended drawings are not necessarily drawn to scale and that the dimensions of some features of the present invention may have been exaggerated for the sake of clarity. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The invention will below be described for a vehicle in the form of a truck 1 such as the one illustrated in Fig. 1. The truck 1 should be seen as an example of a vehicle which could comprise an air intake system according to the present invention. However, the air intake system of the present invention may be implemented in a plurality of different types of objects, e.g. other types of vehicles. Purely by way of example, the air intake system could be implemented in a truck, a tractor, a car, a bus, a work machine such as a wheel loader or an articulated hauler or any other type of construction equipment. The truck 1 comprises an internal combustion engine 10.

Fig. 2 illustrates a cross-sectional view of an embodiment of an air intake system 12. The Fig. 2 air intake system suitable for being used in an internal combustion engine, such as the internal combustion engine 10 illustrated in Fig. 1.

Purely by way of example, the air intake system 12 may be made of a metal or a metal alloy, such as steel or aluminium, or can be made of polymer or composite material such as fibre reinforced polymer. Moreover, as a non-limiting example, the total volume of the air intake system 12 may be within the range of 10 to 40 litres.

The Fig. 2 embodiment of the air intake system 12 comprises an air inlet 14. Moreover, the Fig. 2 air intake system 12 comprises a first outlet set 16 comprising at least one first outlet 18. In the embodiment of the air intake system 12 illustrated in Fig. 2, the first outlet set 16 comprises three outlets 18, 20, 22.

Moreover, the embodiment of the air intake system 12 comprises a second outlet set 24 comprising at least one second outlet 26. In the embodiment of the air intake system 12 illustrated in Fig. 2, the second outlet set 24 comprises three outlets 26, 28, 30. In the shown embodiment, the two set of outlets, and the outlets within each set, are aligned along a lateral direction.

Further, Fig. 2 illustrates that the air intake system 12 comprises at least one exhaust gas recirculation inlet 32. In the Fig. 2 embodiment, the air intake system 12 comprises two exhaust gas recirculation inlets 32, 34. Additionally, the air intake system 12 illustrated in Fig. 2 comprises an internal wall assembly 36 comprising at least one wall 38 for distributing recirculated exhaust gases from the exhaust gas recirculation inlet 32, 34 towards the outlets 18, 20, 22, 26, 28, 30. As may be gleaned from Fig. 2, the internal wall assembly 36 delimits a first conduit portion 40 for conveying air to the first outlet set 16 and a second conduit portion 42 for conveying air to the second outlet set 24.

In the Fig. 2 embodiment of the air intake system 12, the first and second conduit portions 40, 42 are not completely separated. As such, the Fig. 2 air intake system 12 comprises a gap 41 , located between the internal wall assembly 36 and the outer wall assembly 43 delimiting the air intake system 12. The purpose of the gap 41 may be to allow cross-flow between cylinders (not shown) associated with the first outlet set 16 and cylinders (not shown) associated with the second outlet set 24. However, in other embodiments of the air intake system 12, the first and second conduit portions may be separated.

Moreover, Fig. 2 illustrates that the internal wall assembly 36 is positioned in relation to the at least one exhaust gas recirculation inlet 32, 34 for distributing recirculated exhaust gases from the inlet 14 towards the outlets 18, 20, 22, 26, 28, 30 via both the first conduit portion 40 and the second conduit portion 42. Purely by way of example, at least one, though preferably both, of the first and second conduit portions 40, 42 may be adapted to be permanently open. As such, at least one, though preferably both, of the first and second conduit portions 40, 42 may be free from valves, hatches or the like (not shown) that are adapted to close the conduit portion.

Fig. 2 also illustrates that the air intake system 12 may extend in a longitudinal direction L, a height direction H and a lateral direction T. The height and lateral directions H, T form an extension plane P. An intended flow direction from the air inlet 14 towards the upstream portion of the internal wall assembly comprises a flow direction component that extends in the extension plane P.

The lateral direction T extends along a lateral dimension, the longitudinal direction L extends along a longitudinal dimension and the height direction H extends along a height dimension. Fig. 2 illustrates an embodiment of the air intake system 12 wherein the first outlet 18 of the first outlet set 16 and the second outlet 26 of the second outlet set 24 are located at a lateral distance D_T from one another along a lateral dimension. At least a portion of the internal wall assembly 38 is located between the first outlet 18 and the second outlet 26 in the lateral dimension. Purely by way of example, the lateral direction T and the engine axis (not shown) of the engine (engine) to which the air intake system 12 is adapted to be connected may form an angle that is less than or equal to 30°. As a non-limiting example, the lateral direction T and the engine axis may form an angle that is less than 15°, optionally less than 10°. Fig. 2 further illustrates that the embodiment of the air intake system 12 illustrated therein has an intended flow direction from the air inlet towards 12 the first and second outlet sets 16, 24. Moreover, the implementation of the internal wall assembly 38 illustrated in Fig. 2 comprises an upstream portion 44 located closest to the air inlet 14 in a direction opposite of the intended flow direction.

Moreover, Fig. 2 illustrates, an embodiment of an air intake system 12 which comprises a first exhaust gas recirculation inlet 32 located in the first conduit portion 40 and a second exhaust gas recirculation inlet 34 located in the second conduit portion 42. Each one of the first and second exhaust gas recirculation inlets 40, 42 is located at least partially downstream of the upstream portion 44.

In the embodiment of the air intake system 12 illustrated in Fig. 2, the air intake system is adapted to discharge fluid from the first outlet set 16 in an outlet direction OD that is substantially parallel to the longitudinal direction L. Moreover, in the Fig. 2 embodiment, each one of the first and second exhaust gas recirculation inlets 32, 34 is oriented such that exhaust gas is discharged into the air intake system in a discharge direction that is substantially parallel to the longitudinal direction L. As such, and as is indicated in Fig. 2, the exhaust gas recirculation inlets 32, 34 are adapted to discharge recirculated exhaust gas in a direction that is substantially perpendicular to the flow direction of the intake air that passes the exhaust gas recirculation inlets 32, 34.

Fig. 2 further illustrates that the air intake system may comprise an inlet manifold portion 12' and an air conduit portion 12". The inlet manifold portion 12' comprises said first outlet set 16 and second outlet set 24. The air conduit portion 12" comprises the air inlet 14. The inlet manifold portion 12' and the air conduit portion 12" may be connected to one another at a junction 13.

Purely by way of example, and as is intimated in Fig. 2, the at least one exhaust gas recirculation inlet 32, 24 is positioned at the junction 13.

The air conduit portion 12" defines an air flow direction in its longitudinal direction from the air inlet 14 towards the junction 13. The inlet manifold portion 12' extends in a lateral direction T defined by an axis intersecting the first outlet 18 and the second outlet 26. The longitudinal direction of the air conduit portion 12" is substantially in parallel with the lateral direction T of the inlet manifold portion 12'. The air conduit portion 12" and the inlet manifold portion 12' may have a side wall defining the respective internal chambers in common. The junction 13 between the inlet manifold portion 12' and the air conduit portion 12" is positioned between the first and second outlet sets 16,24 in a lateral direction T defined by an axis intersecting the first outlet 18 and the second outlet 26.

The inlet manifold portion 12' may be defined by an external peripheral side wall defining a volume or chamber which is substantially tubular, which in the example extends along the lateral direction T. The air conduit portion 12" may be defined by an external peripheral side wall defining a volume or chamber which is substantially tubular, which in the example extends along the lateral direction T. In the shown example, the two portions extend along directions which are substantially parallel, but are offset one from the other, in this example along the height direction. The offset could be along the longitudinal direction. In the shown example, the two volumes are contiguous one to the other, so that the junction 13 can be seen as a common aperture in the external peripheral walls defining the volumes of the inlet manifold portion 12' and of the air conduit portion 12".

The two exhaust gas recirculation inlets 32, 34 are positioned at the junction 13 between the inlet manifold portion 12' and said air conduit portion 12". A pipe portion of each of the exhaust gas recirculation inlets 32, 34 project into the air stream chamber defined by the respective conduit portion. Each of the exhaust gas recirculation inlets 32, 34 has a cross section shape so that a first part of the inlet is positioned in the air conduit portion 12" and a second part of the inlet is positioned in the inlet manifold portion 12'. More specifically, each of the exhaust gas recirculation inlets 32, 34 has such an extension that it bridges a distance between the air conduit portion 12" and the inlet manifold portion 12', which distance is defined by a wall thickness of the inlet manifold portion 12'.

At least a portion of said internal wall assembly 36 is positioned at the junction 13 5 between the inlet manifold portion 12' and said air conduit portion 12". More specifically, the internal wall assembly 36 is arranged so that an upstream portion 44 thereof is located in the air conduit portion 12" and a downstream portion thereof is located in the inlet manifold portion 12'. The internal wall assembly 36 has a curved shape between the upstream portion 44 and the downstream portion for an at least 90° deflection of part of an

10 incoming air towards the second outlet set 24 during operation. In the shown example, the internal wall assembly 36 has a curved shape between the upstream portion 44 and the downstream portion for a substantial U-turn (i.e. 180° deflection) of part of an incoming air towards the second outlet set 24 during operation, while the other part of the incoming air on the other side of the internal wall assembly 36 is deflected to a maximum of 90°

15 (primarily achieved by a curvature of the side wall of the air conduit portion 12"). The engine^'s cylinders may be arranged in a row, especially along a straight line, which defines the engine's engine axis (not shown). Since the outlets 18, 20, 22, 26, 28, 30 are arranged for supplying the cylinders with air, the outlets are likewise positioned along a straight line. Purely by way of example, location of the junction 13 on the air intake system

20 12 may be such that when the air intake system 12 is connected to an engine (not shown), the junction 13 is located, in the lateral dimension, approximately in the centre of the engine's engine axis.

As a non-limiting example, at least a portion of the air conduit portion 2" may extend in a 25 direction that has a component that extends in the lateral direction.

The internal wall assembly 36 may extend at least partially from the air inlet 14 to the first and second outlet sets 16, 24. Fig. 3 illustrates a top view of the Fig. 2 air intake system 12.

30

Fig. 4 illustrates a portion of the Fig. 2 embodiment of the air intake system 12. As may be gleaned from Fig. 4, the internal wall assembly 36 may comprise a first internal wall assembly portion 46 extending from the upstream portion 44 along a first wall axis A in the extension plane P. In the implementation illustrated in Fig. 4, the first wall axis is 35 substantially parallel to the lateral direction T. Moreover, the internal wall assembly 36 further comprises a second internal wall assembly portion 48 extending from the first internal wall assembly portion 46 along a second wall axis A₂ in the extension plane P. The first and second wall axes A₂ may form a first angle a, of at least 45°. In the embodiment illustrated in Fig. 4, the first angle C is approximately 90°.

Moreover, in the embodiment of the air intake system 12 illustrated in Fig. 4, the internal wall assembly 36 comprises a third internal wall assembly portion 50 extending from the second internal wall assembly portion 48 along a third wall axis A₃ in the extension plane P. The second axis 48 and the third axis 50 form a second angle a₂ of at least 30°.

Further, in the Fig. 4 embodiment, the first wall axis A has a first axis lateral component and the third wall axis A₃ has a third axis lateral component, the first and third axis lateral components extending in opposite directions.

The second internal wall assembly portion 48 is located between the first outlet set 16 and the second outlet set 24 in the lateral direction T.

In the shown embodiment, the first and second conduit portions 40, 42 are delimited by the internal wall assembly inside a volume of the air intake systems which is itself delimited by an external peripheral wall of the air intake system. In the shown embodiment, the first and second conduit portions 40, 42 extend in part in the air conduit portion 12' and in part in the inlet manifold portion 12'.

As may be gleaned from Fig. 5, the upstream portion 44 may have an upstream portion thickness W_e, i.e. an extension in a direction perpendicular to the intended flow direction around the upstream portion 44, in the extension plane and an adjacent portion of the internal wall assembly may have an adjacent portion thickness W_a. Purely by way of example, the upstream portion thickness W_e may be at least two times greater than the adjacent portion thickness W_a. In the implementation of the internal wall assembly illustrated in Fig. 5, the upstream portion thickness W_e is approximately three times greater than the than the adjacent portion thickness W_a. Fig. 6 illustrates embodiment perspective view of the air intake system 12.

Finally, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.

Claims

1. An air intake system (12) for an internal combustion engine (10), said air intake system (12) comprising an air inlet (14), a first outlet set (16) comprising at least one first outlet (18, 20, 22), a second outlet set (24) comprising at least one second outlet (26, 28, 30), at least one exhaust gas recirculation inlet (32, 34) and an internal wall assembly (36) comprising at least one wall (38) for distributing recirculated exhaust gases from said exhaust gas recirculation inlet (32, 34) towards the outlets (18, 20, 22), c h a r a ct e r i z e d i n t h a t said internal wall assembly (36) delimits a first conduit portion (40) for conveying air to the first outlet set (16) and a second conduit portion (42) for conveying air to the second outlet set (24), and that said internal wall assembly (36) is positioned in relation to said at least one exhaust gas recirculation inlet (32, 34) for distributing recirculated exhaust gases from said exhaust gas recirculation inlet (32, 34) towards the outlets (18, 20, 22, 26, 28, 30) via both the first conduit portion (40) and the second conduit portion (42).

The air intake system (12) according to claim 1 , wherein said first outlet (18) of said first outlet set (16) and said second outlet (26) of said second outlet set (24) are located at a lateral distance from one another along a lateral direction (T), at least a portion of said internal wall assembly (36) being located between said first outlet (18) and said second outlet (26) in said lateral direction (T).

The air intake system (12) according to claim 1 or 2, wherein said air intake system (12) has an intended flow direction from said air inlet (14) towards said first and second outlet sets (16, 24), said internal wall assembly (36) comprising an upstream portion (44) located closest to said air inlet (14), said air intake system (12) comprising a first exhaust gas recirculation inlet (32) located in said first conduit portion (40) and a second exhaust gas recirculation inlet (34) located in said second conduit portion (42), each one of said first and second exhaust gas recirculation inlets (32, 34) being located at least partially downstream of said upstream portion (44).

The air intake system (12) according to any one of the preceding claims, wherein said internal wall assembly (36) extends at least partially from said air inlet (14) to said first and second outlet set (24).

5. The air intake system (12) according to any one of the preceding claims, wherein the air intake system (12) comprises an air conduit portion (12"), which comprises said air inlet (14), and an inlet manifold portion (12'), which comprises said first outlet set (16) and second outlet set (24), and wherein said air conduit portion (12") is connected to said inlet manifold portion (12').

6. The air intake system (12) according to claim 5, wherein the air conduit portion (12") defines an air flow direction in its longitudinal direction, wherein said inlet manifold portion (12') extends in a lateral direction (T) defined by an axis intersecting the first outlet (18) and the second outlet (26) and wherein the longitudinal direction of the air conduit portion (12") is substantially in parallel with the lateral direction (T) of the inlet manifold portion (12').

7. The air intake system (12) according to claim 5 or 6, wherein a junction (13) between the inlet manifold portion (12') and the air conduit portion (12") is positioned between the first and second outlet sets (16,24) in a lateral direction (T) defined by an axis intersecting the first outlet (18) and the second outlet (26).

8. The air intake system (12) according to anyone of claims 5-7, wherein said at least one exhaust gas recirculation inlet (32, 34) is positioned at a junction (13) between the inlet manifold portion (12') and said air conduit portion (12").

9. The air intake system (12) according to anyone of claims 5-8, wherein at least a portion of said internal wall assembly (36) positioned at a junction (13) between the inlet manifold portion (12') and said air conduit portion (12").

10. The air intake system (12) according to claim 9, wherein the internal wall assembly (36) is arranged so that an upstream portion (44) thereof is located in the air conduit portion (12") and a downstream portion thereof is located in the inlet

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1 1. The air intake system (12) according to claim 10, wherein the internal wall assembly (36) has a curved shape between the upstream portion (44) and the downstream portion for an at least 90° deflection of part of an incoming air towards the second outlet set (24) during operation.

12. The air intake system (12) according to any one of the preceding claims, wherein said air intake system (12) extends in a longitudinal direction (L), a height direction (H) and a lateral direction (T), said height and lateral directions (H, T) forming an extension plane (P), wherein an intended flow direction from said air inlet (14) towards said upstream portion of said internal wall assembly (36) comprises a flow direction component extending in said extension plane (P).

13. The air intake system (12) according to claim 12, wherein said internal wall assembly (36) comprises a first internal wall assembly portion (46) extending from said upstream portion (44) along a first wall axis (A,) in said extension plane (P), said internal wall assembly (36) further comprising a second internal wall assembly portion (48) extending from said first internal wall assembly portion (46) along a second wall axis (A₂) in said extension plane (P), said first and second axes (Ai, A₂) forming a first angle (OH) of at least 45°.

14. The air intake system (12) according to claim 13, wherein said internal wall assembly (36) comprises a third internal wall assembly portion (50) extending from said second internal wall assembly portion (48) along a third wall axis (A₃) in said extension plane (P), said second and third axes (A₂, A₃) forming a second angle of at least 30°.

15. The air intake system (12) according to claim 14, wherein said first axis has a first axis lateral component and said third axis has a third axis lateral component, said first and third axis lateral components extending in opposite directions.

16. The air intake system (12) according to any one of claims 13-15, wherein said first wall direction is substantially parallel to said lateral direction (T).

17. The air intake system (12) according to any one of claims 13-16, wherein said second internal wall assembly portion (48) is located between said first outlet set (16) and said second outlet set (24) in said lateral direction.

18. The air intake system (12) according to any one of claims 12-17, wherein said air intake system is adapted to discharge fluid from said first outlet set (16) in an outlet direction (OD) that is substantially parallel to said longitudinal direction (L) of the air intake system.

19. The air intake system (12) according to any one of claims 12-18, wherein each one of said first and second exhaust gas recirculation inlets (32, 34) is oriented such that exhaust gas is discharged into said air intake system in a discharge direction that is substantially parallel to said longitudinal direction (L).

20. The air intake system (12) according to any one of the preceding claims, wherein each one of said first and second conduit portions (40, 42) are adapted to be permanently open.

21. The air intake system (12) according to any one of the preceding claims, wherein said upstream portion (44) has an upstream portion thickness (W_e) in said extension plane (P) and an adjacent portion of said internal wall assembly (36) has an adjacent portion thickness (W_a), said upstream portion thickness (W_e) being at least two times greater than said adjacent portion thickness (W_a).

22. An internal combustion engine (10) comprising an air intake system (12) according to any one of the preceding claims.

23. A vehicle comprising an internal combustion engine (10) according to claim 22 and/or an air intake system (12) according to any one of claims 1 to 21.