WO2019145212A1

WO2019145212A1 - Optimised air intake circuit for a power train of a vehicle

Info

Publication number: WO2019145212A1
Application number: PCT/EP2019/051105
Authority: WO
Inventors: Thomas VENEZIANI
Original assignee: Renault S.A.S
Priority date: 2018-01-24
Filing date: 2019-01-17
Publication date: 2019-08-01
Also published as: FR3077092A1; FR3077092B1

Abstract

The invention concerns an air intake circuit (1, 100) for a power train comprising a cylinder head (9, 109) and a direct injection petrol engine (5, 105), said engine (5, 105) comprising at least one combustion chamber (6, 106), said intake circuit (1, 100) comprising a water/air exchanger (3, 103) and a plenum (4, 104) having at least one pipe (8, 108) intended to supply air to said at least one chamber (6, 106). The main feature of an intake circuit (100) according to the invention is that the plenum (104) is produced in two parts (111, 112), a first part (111) comprising each pipe (108) and a deflector (110) associated with each of said pipes (108), and a second part (112) linking said first part (111) to the exchanger (103), the first part (111) and the second part (112) defining an interface plane (120) that is parallel to the deflector (110).

Description

OPTIMIZED AIR INTAKE CIRCUIT FOR A GROUP

VEHICLE MOTOR POWERS

The invention relates to an optimized air intake circuit of a powertrain of a vehicle.

Schematically, a powertrain of a vehicle, comprises a fresh air intake circuit, a motor with combustion chambers and pistons, and an exhaust system capable of evacuating the exhaust gases from said chambers. The intake circuit generally comprises a water / air exchanger and a distributor composed of several ducts in parallel, each intended to convey fresh air into a combustion chamber of said engine. The exchanger is placed upstream of the distributor within the intake circuit and allows the air to cool before it enters the engine chambers.

An air intake circuit according to the invention is designed to lighten the powertrain and make it less bulky, while limiting the pressure losses and promoting the "tumble" in the combustion chambers of the engine.

As a reminder, the tumble is an aerodynamic movement of the roll-shaped gases inside the combustion chamber. The inlet gases are injected into the cylinders and specifically into the combustion chambers to generate "roller" vortices in the spark ignition engines, making it possible to achieve, using a particular shape of the head of the piston, a stratified charge of fuel in the combustion chamber. To do this, the fuel jet is deflected perpendicularly to the axis of the cylinder towards the ignition point of the mixture, namely the spark plug.

The invention relates to an air intake circuit of a power unit comprising a cylinder head and a spark ignition engine, said engine comprising at least one combustion chamber, said intake circuit comprising a distributor defining a plenum connected to at minus a substantially tubular and rectilinear intake duct for supplying air to said at least one chamber.

According to the invention, the distributor is made in two parts, a first part dug in the cylinder head and comprising a deflector associated with each of said conduits, and a second outer portion and sealed to the cylinder head according to an interface plane which is inclined with respect to a horizontal plane of junction of the cylinder head with a crankcase. In this way, compared to existing configurations, the first part of the plenum remains unchanged, only the second part of the plenum is delimited by a wall external to the cylinder head, to significantly reduce the weight of the assembly. It is sufficient for the second part of the plenum, to choose a lighter material and cheaper than that of the cylinder head, to lighten the air intake line and therefore the vehicle. It should be noted that the second part of the plenum may either be an independent piece manufactured separately, or be an extension of a housing housing the exchanger, and in this case, the housing and the second part are one and the same. part manufactured during the same operation. The deflector is a wall located upstream of a duct of the first part of the plenum, and the connection between the first part and the second part defines an interface plane between said parts, which is inclined with respect to the horizontal plane parallel to the joint plane between the cylinder head and the crankcase. Such a configuration results in a reduction of the pressure drops and promotes the tumble in the combustion chambers.

Preferably, the deflector is inclined relative to a horizontal plane of junction of the cylinder head with the cylinder block in the same direction as the interface plane.

Preferably, the distributor is attached to an exchanger extending along an axis parallel to the axis of the at least one conduit.

Advantageously, the second part is a frame having an elongated upper edge and an elongated lower edge interconnected by two triangular-shaped lateral edges, the upper edge being thin and extending along of a straight line, and the lower edge being spread out and extending in a plane so that said second portion delimits a prism-shaped core. Preferably, the two lateral edges are located at the ends of the lower edge and at the ends of the upper edge. Advantageously, the upper edge and the lower edge extend in a substantially horizontal direction.

Preferably, the upper edge and the lower edge are parallel, the length of the upper edge being less than that of the lower edge, so that the two side edges are divergent relative to each other. In this way, the air coming from the exchanger can be distributed in an enlarged manner thanks to the presence of the two diverging lateral edges, in the most extreme ducts of the plenum. The two side edges contribute to flaring the air outlet from the exchanger, to ensure an expanded distribution of air output of said second part.

Preferably, the second portion has an upstream opening opening in the exchanger and a downstream opening opening in the first part, said two openings being inclined relative to each other by an angle less than 45 °.

Advantageously, the second part has an upper flange originating on the upper edge and extending along it, said upper flange constituting an extension of said upper edge and for securing said second part to the yoke. Preferably, this upper flange has holes so as to allow the passage of fixing screws. This flange makes it possible to fix the second part of the plenum to the cylinder head while preserving the functional form of said second part. Indeed, this flange is an isolated element of the second part, which does not interfere with the passage of air from the exchanger.

Advantageously, the exchanger has a parallelepipedal shape, the upper flange extending perpendicularly to an axis of extension of said exchanger. In this way, once the second part has been positioned relative to the heat exchanger, the flange protrudes from said heat exchanger and thus allows easy use of a tool, such as a screwdriver to fix the screws that pass through said flange.

Preferably, according to one embodiment, the second portion has a lower lip with a beveled edge cooperating with a profiled strip fixed to the yoke, said lip being inserted between the yoke and said strip. This lip, in association with the slide, plays the role of a pre-positioning device of the second part on the cylinder head.

Preferably, the slider is bevelled.

Preferably, the second part is made of plastic material. Plastic has good mechanical strength while remaining light.

Another object of the invention is a method of mounting an air intake circuit according to the invention.

According to the invention, said method comprises the following steps:

> A step of insertion of the lip of the second part between the yoke and the slide, in order to pre-position the second part with respect to said bolt,

> A pivoting step of the second part around the end of the lip inserted between the yoke and the slide, so as to bring the upper flange of said second part against the yoke,

> A step of fixing the upper flange to the cylinder head,

If the exchanger and the second part of the plenum are two separate parts, a mounting method according to the invention comprises an additional step of connecting the exchanger with the second part, said connection being made sealingly. This connection can, for example, be realized by welding or screwing.

If the heat exchanger and the second part form the same part, said exchanger is mounted simultaneously with said second part, during the three preceding main stages.

An air intake circuit according to the invention has the advantage of being compact and contributing to lighten the mass of the vehicle, while reducing the pressure losses and while ensuring the tumble in the combustion chambers of the engine . It also has the advantage of being achieved through minor modifications of existing air intake circuits, and can therefore be easily implemented in existing vehicles.

The following is a detailed description of a preferred embodiment of an air intake circuit according to the invention, with reference to the following figures:

FIG. 1A is a side view of an air intake circuit according to the state of the art,

FIG. 1B is a view from another angle of the air intake circuit of FIG.

FIG. 2 is a side view of an air intake circuit according to the invention,

FIG. 3 is a perspective view of a second plenum part and an exchanger of an air intake circuit according to the invention,

FIGS. 4A, 4B and 4C are three side views of a second plenum part and a cylinder head of an air intake circuit according to the invention, respectively during a first, a second and third step of mounting said second plenum part in the cylinder head Referring to FIGS. 1A and 1B, an air intake circuit 1 according to the state of the art comprises schematically from upstream to downstream, an air inlet 2, a water / air exchanger 3, and a distributor with a plenum

4 attached to a cylinder head of a direct injection gasoline engine 5 and connected to air or gas inlet ducts opening into combustion chambers. Said combustion chambers 6 are each associated with a piston, the fuel injection being carried out directly in each of said chambers 6. Generally, intake valves 7 and exhaust valves 7 regulate the passage respectively of the air and exhaust gas through the intake ducts to said chambers 6. The plenum 4 is a piece placed downstream of the exchanger 3 and upstream of the engine 5, and which is connected to several ducts 8 arranged in parallel, each duct 8 being intended to supply combustion chamber 6 of the engine

5 There is thus at least as many ducts 8 as there are combustion chambers 6 in the engine 5. Generally, there are two intake ducts 8 per combustion chamber 6 in order to ability to generate a swirling airflow in the combustion chamber. The water / air heat exchanger 3 is fixed to a cylinder head 9 and the plenum 4 is partially hollowed out in said cylinder head 9. A baffle 10 is placed upstream of each pipe 8, to direct the flow of air in said pipes. 8 and thus improve the air supply conditions of each chamber 6.

However, this arrangement of the exchanger 3, the plenum 6 and the cylinder head 9 is not optimized in terms of compacting and lightening.

Thus, with reference to FIG. 2, in order to reduce the compaction and the mass of the arrangement of these elements, an air intake circuit 100 according to the invention comprises a two-part plenum 104, 112. More specifically, the plenum 104 comprises a first portion 111 including the ducts 108 and approximately corresponding to an existing plenum 4, and a second portion 112 being inserted between said first portion 111 and the water / air exchanger 103. This second part 112 may constitute either an autonomous part manufactured separately, or an extension of the exchanger 103, and in this case, said second part 112 and said exchanger 103 form a common piece part, manufactured during a single operation. To be more Specifically, the exchanger 103 is generally housed in a housing, and the second portion 112 of the plenum may be an extension of this housing. This second portion 112 of the plenum 104 is preferably made of a material which is lighter than that of the cylinder head 109. This material may for example be plastic. For the following description, we consider that the second part 112 is a separate piece, not part of the exchanger 103.

Referring to Figures 2 and 3, this second portion 112 of the plenum 104 is in the form of a frame, comprising an upper edge 113, a lower edge 114 and two side edges 115, 116 connecting said upper edge 113 and said lower edge 114. The upper edge 113 and the lower edge 114 are parallel and extend in a substantially horizontal direction. The upper edge 113 is elongated and thin, and extends along a straight line. The lower edge 114 extends in a plane and has a rectangular shape. The two side edges 115, 116 each have a triangular shape, and extend from the upper edge 113 to the lower edge gradually widening. They connect the upper edge 113 to the lower edge 114 at the ends of said edges 113, 114. The length of the upper edge 113 being smaller than that of the lower edge 114, the two side edges 115, 116 are divergent with respect to the other, being tightened at the upper edge 113 and progressively away from each other when they join the lower edge 114. In this way, the fresh air from the exchanger 103 can be routed in all conduits 108 of the plenum 104, including those in the most remote. The core of this second plenum portion 104 has the shape of a prism. This second portion 112 has two openings 117, 118 originating at the upper edge 113 and extending to the lower edge 114, making between them an angle less than 45 °. In other words, the two openings 117, 118 thus form a bend around said upper edge 113, whose angular amplitude does not exceed 45 °. One of the two openings 117 is intended to open into the exchanger 103 and another opening 118 is intended to open into the first portion 111 of the plenum 103. The lower edge 114 of said second portion 112 may be extended by a tab of attachment 140 or by a lip 121 extending along the entire length of said lower edge 114, said lip 121 being assimilable to an extension of the lower edge 114.

The upper edge 113 is extended by an upper flange 119 extending along said upper edge 113 over its entire length. This upper flange 119 has a plurality of holes for the passage of screws, for fixing the second portion 112 of the plenum 104 on the cylinder head 109.

The lip 121 and the flange 119 constitute two opposite ends of the second portion 112 of the plenum 103.

Referring to FIG. 2, the first portion 111 and the second portion 112 of the plenum 104 are affixed to each other so as to have an interface plane 120 which is substantially parallel to a deflector 110 present in said first part 111, upstream of the ducts 108.

The principle of an air intake circuit 100 according to the invention consists in replacing a part of the cylinder head 109 by the second part 112 of the plenum 104, allowing on the one hand, to compact all the elements relating to the circuit. air intake 100, and lighten said circuit 100. These two advantages are obtained by means of a judicious arrangement and a particular geometry of the main elements constituting the air intake circuit 100, namely the exchanger 103, the plenum 104 and the cylinder head 109. This arrangement has also been designed to limit the pressure drop and promote the tumble in the combustion chambers 6, 106 of the engine 5, 105.

A method of mounting an air intake circuit 100 according to the invention comprises the following main steps:

> A step of fixing a strip 122 in the shape of a dovetail to the cylinder head 109

> A step of insertion of the lip 121 of the second part 112 between the yoke 109 and said strip 122, in order to pre-position said second part 112 with respect to said yoke 109,

A pivoting step of the second portion 112 around the end of the lip 121 inserted between the yoke 109 and the slider 122, so as to bring the upper flange 119 of said second portion 112 into contact with the yoke 109, > A step of fixing the second portion 112 of the plenum 104 on the cylinder head 109, by screwing the screws through the upper flange 119 of said second portion 112. It should be noted that the upper flange 119 extends in a direction which is perpendicular to an axis along which the exchanger 103 extends. This upper flange 119 therefore constitutes a protruding protrusion, which is easily accessible by a tool, which may for example be a screwdriver.

Claims

An air intake circuit (1, 100) of a power train comprising a cylinder head (9, 109) and a spark ignition engine (5, 105), said engine (5, 105) comprising at least one combustion chamber (6, 106), said intake circuit (1, 100) having a distributor defining a plenum (4, 104) connected to at least one substantially tubular and straight inlet duct (8, 108) for supplying said at least one chamber (6, 106) with air, characterized in that the distributor is made in two parts (111, 112), a first part (111) hollowed out in the cylinder head and comprising a deflector (110) associated with each of said conduits (108), and a second outer portion (112) and sealingly attached to the cylinder head (9, 109) in an interface plane (120) which is inclined with respect to a horizontal plane of junction of the cylinder head (9, 109) with a crankcase.

2. Air intake circuit according to claim 1, characterized in that the deflector (110) is inclined relative to a horizontal plane of junction of the cylinder head (9, 109) with the crankcase in the same direction as the interface plane (120).

Air intake circuit according to Claim 1 or 2, characterized in that the distributor is attached to an exchanger (3, 103) extending along an axis parallel to the axis of the at least one duct (108). ).

Air intake system according to one of claims 1 to 3, characterized in that the second part (112) is a frame having an elongated upper edge (113) and an elongated lower edge (114) connected between them by two lateral edges (115, 116) of triangular shape, and in that the upper edge (113) is thin and extends along a straight line, and the lower edge (114) is spread out and extends in a plane, so that said second portion (112) delimits a prism-shaped core.

Air intake system according to claim 4, characterized in that the upper edge (113) and the lower edge (114) are parallel, and in that that the length of the upper edge (113) is smaller than that of the lower edge (114) so that the two side edges (115, 116) are divergent with respect to each other.

6. air intake circuit according to claim 3, characterized in that the second portion (112) has an upstream opening (117) opening into the exchanger (103) and a downstream opening (118) opening into the first part (111), and in that said two openings (117, 118) are inclined relative to each other by an angle less than 45 °.

An air intake circuit according to any one of claims 4 to 6, characterized in that the second portion (112) has an upper flange (119) originating on the upper edge (119) and extending along the latter, and in that said upper flange (119) is an extension of said upper edge (113) and secures said second portion (112) to the yoke (109).

8. Air intake circuit according to claim 7, characterized in that the exchanger (103) has a parallelepipedal shape and in that the upper flange (119) extends perpendicular to an axis of extension of said exchanger (103).

9. Air intake circuit according to any one of claims 1 to 8, characterized in that the second portion (112) has a lower lip with a beveled edge cooperating with a strip (122) profile attached to the cylinder head (109), said lip (121) being inserted between the yoke (109) and said strip (122).

10. Air intake circuit according to any one of claims 1 to 9, characterized in that the second portion (112) is made of lightweight material.