EP3134635B1 - Intake manifold for an internal combustion engine of an automotive vehicle - Google Patents

Description

The invention relates to an intake manifold for an internal combustion engine of a motor vehicle.

An intake manifold, also called a distributor, has the function of supplying, to each cylinder of the engine, the quantity of air necessary for complete combustion of the fuel.

Some engines are equipped with exhaust gas recirculation (EGR), which lowers the level of oxygen in the air fuel mixture. In general, these recycled exhaust gases are brought to the intake manifold by a metal pipe opening inside the intake manifold. In the latter, the diffusion of the recycled exhaust gases with the fresh air coming from the air filter is obtained by a gas diffuser, generally arranged at the junction between the supply pipe of the recycled exhaust gases and the intake manifold. In some engines, the intake manifold is made of a polymeric material and the diffuser is a metallic insert, for example stainless steel. This metallic diffuser comprises a frustoconical part, the larger diameter end of which is connected to the EGR pipe and the smaller diameter end is connected to a cylindrical part which protrudes inside the intake manifold. The free end of the cylindrical part, located substantially in the center of the intake manifold, has side openings for the diffusion of gases. This arrangement makes it possible to prevent the exhaust gases from coming into direct contact with the polymer material constituting the intake manifold, thus protecting the walls thereof from the heat of the EGRs. However, dissemination is not always optimal. In addition, this diffuser is generally welded to the mouth of the exhaust gas supply pipe. There is thus a risk of the diffuser becoming detached and of the latter falling inside the intake manifold, liable to disrupt the operation of the engine and damage it. Finally, such a diffuser made of metallic material is relatively expensive to produce.

The publication US 2012/180478-A1 proposes an intake manifold of an engine having a gas distribution by passages made on an element arranged in the inlet of said intake manifold.

There is therefore a need to improve the diffusion of EGR gases inside an intake manifold, in particular by making it safer and at lower cost.

To this end, the invention relates to a metallic air intake manifold for supplying air to the cylinders of an internal combustion engine according to claim 1. Thus, the passage forms a diffuser integrated into the intake manifold d 'air. There is thus no longer any risk of the diffuser disconnecting from the intake manifold, thus reducing the risk of engine failure. In other words, the air intake manifold according to the invention has a diffuser made in one piece with the manifold. This diffuser integrated into the wall of the intake manifold therefore does not include any protruding part towards the interior of the intake manifold from the wall of the latter, unlike the attached diffusers of the prior art. The arrangement according to the invention, however, makes it possible to obtain a good diffusion of the EGR inside the intake manifold by choosing an appropriate shape of the restricted section and of elongated shape, the portion whose section decreases allowing acceleration. gases. The intake manifold according to the invention can in particular be produced in a simple manner by molding, for example in aluminum.

Advantageously and in a nonlimiting manner, the passage may have a portion of flared shape between the restricted section and an internal end of said passage. Such a flared shape makes it possible to improve the redirection of the gases passing through said passage towards the interior of the intake manifold, in particular towards the cylinders of the engine. This shape The flare may extend from the restricted section or from a portion of constant section adjacent to the restricted section.

In particular, the portion of flared shape may have at least one shoulder, which may also promote the orientation of the gas flowing in said passage towards the cylinders of the engine.

In general, the shape of the portion of which the section continuously decreases can be determined in order to allow acceleration of the incoming gases, in particular sufficient to allow the diffusion of these gases. This determination is part of the knowledge of those skilled in the art.

According to the invention and for a simpler embodiment, the portion whose section continuously decreases may have a frustoconical or substantially frustoconical, symmetrical or asymmetrical shape. Correct acceleration of the incoming gases can for example be obtained with an angle at the top of the frustoconical or substantially frustoconical shape of 15 ° to 35 °, preferably 20 ° to 30 °. This angle may however be adapted depending on the shape of the intake manifold considered.

Advantageously and in a nonlimiting manner, the restricted section can extend at least in part in a plane inclined with respect to a plane containing the external opening of the passage. This can allow the gases flowing within the passage to be directed more efficiently to the cylinders to which the intake manifold is connected. Thus, for example, a part of the restricted section which extends in an inclined plane can make it possible to direct the gases towards a cylinder arranged at one end of the intake manifold, on the side where this inclined plane extends.

The restricted section may also extend partly in a first plane, for example parallel to the plane containing the external opening, and partly in at least one other plane inclined relative to the latter, depending on the orientation that the 'we want to give the incoming gases through the passage.

In order to improve the distribution of the gas flowing inside the passage to the cylinders of the engine, the restricted section may have an oblong shape with rounded edges, for example chosen from an oval, an ellipse, a shape similar to a pear, a crescent-like shape, a shape having two parallel edges connected by rounded ends, a shape having two parallel edges connected by portions of a circle with a diameter greater than the distance between the parallel edges, a combination of one or more of these shapes or any other oblong shape. These oblong shapes can extend in one or more planes, as already mentioned.

The restricted section may also have scalloped shapes rounded towards at least one cylinder of the engine to which said intake manifold is connected. In particular, the restricted section may have a notched shape in the direction of each cylinder of the engine, which may make it possible to promote the distribution of the gas flowing in the passage to this cylinder.

The invention also relates to an internal combustion engine comprising an air intake manifold according to the invention and a pipe for recycling the exhaust gases emitted by the engine, said pipe being connected to said external opening of said manifold. air intake.

The invention finally relates to a motor vehicle comprising an internal combustion engine according to the invention.

• la figure 1 est une vue de dessus d'un collecteur d'admission d'air selon un mode de réalisation de l'invention, raccordé à une conduite de recyclage des gaz d'échappement ;
• la figure 2 est une vue similaire à celle de la figure 1, sans la conduite de recyclage des gaz d'échappement ;
• la figure 3 est une vue en coupe selon la ligne AA de la figure 1 ;
• la figure 4 représente une vue en perspective du dessus d'un collecteur d'admission selon un autre mode de réalisation ;
• la figure 5 représente une vue en coupe selon la ligne AA de la figure 4 ;
• la figure 6 représente une vue agrandie de dessus de l'ouverture externe du passage de la figure 4 ;
• la figure 7 est une vue similaire à la figure 6 dans laquelle la section restreinte présente une autre forme.

The invention is now described with reference to the accompanying drawings, not limiting, in which:

• the figure 1 is a top view of an air intake manifold according to one embodiment of the invention, connected to an exhaust gas recirculation pipe;
• the figure 2 is a view similar to that of the figure 1 , without the exhaust gas recirculation line;
• the figure 3 is a sectional view along line AA of the figure 1 ;
• the figure 4 shows a perspective view from above of an intake manifold according to another embodiment;
• the figure 5 shows a sectional view along line AA of the figure 4 ;
• the figure 6 shows an enlarged view from above of the external opening of the passage of the figure 4 ;
• the figure 7 is a view similar to figure 6 in which the restricted section has another shape.

By substantially parallel, perpendicular is meant a direction deviating by at most ± 20 °, or even by at most 10 ° or by at most 5 ° from a parallel, perpendicular direction.

The figure 1 shows a metallic air intake manifold 10 for supplying air to the cylinders of an internal combustion engine. For this purpose, the intake manifold 10 has openings for connection to the cylinders. This intake manifold 10 is connected to a pipe 12 for recycling the exhaust gases emitted by the engine. This pipe 12 is also metallic.

The intake manifold 10 thus has an external opening 14 (visible figures 2 and 3 ) for connecting the exhaust gas recirculation pipe 12. As seen on the figure 3 , this external opening 14 communicates with a passage 16 passing through a wall 18 of the intake manifold 10.

According to the invention, the passage 16 is shaped to diffuse a gas coming from the external opening 14 towards the interior of the intake manifold 10. This passage 16 has in particular a portion 16a the section of which decreases continuously from the external opening 14 up to a restricted section 20. In other words, the portion 16a does not have parts of constant section between the external opening 14 and the restricted section 20. This restricted section 20 is shaped to direct a gas circulating in the passage 16 towards the cylinders of the engine to which the intake manifold 10 is connected. In the example shown on figures 1 to 3 , the intake manifold 10 is connected to four cylinders (not shown).

The portion 16a, the section of which continuously decreases, makes it possible to accelerate the gases entering the passage 16, thus promoting their diffusion inside the intake manifold 10. The shape of the restricted section 20 will allow the flow to be directed. of gas accelerated to the engine cylinders.

It will be noted that in the example represented figures 1-3 , the air intake manifold 10 has a passage 16, a portion 16b of which has a flared shape between the restricted section 20 and an internal end 17 of the passage 16, in other words between the restricted section 20 and the interior of the manifold d 'admission. This portion 16b of flared shape makes it possible to promote the direction of the flow of accelerated gas following its passage through the first portion 16a in the entire volume of the intake manifold 10 and in particular towards the ends of the intake manifold 10 which are connected to cylinders of the engine. This portion 16b of flared shape may in particular have a shoulder 22 for directing the gas flow in different directions inside the intake manifold 10. In this example, the flared section portion 16b is not directly adjacent to the restricted section 20, but is adjacent to a portion 16c of constant section itself adjacent to the restricted section 20.

The section portion 16a, the section of which decreases continuously from the example of figures 1 to 3 has a substantially frustoconical shape. The shape of the restricted section 20, visible on the figure 2 , is roughly oval. It is thus elongated in shape, its ends being directed towards the most distant cylinders to which the intake manifold is connected. In other words, the length of the restricted section 20 of elongated shape extends substantially parallel to a line connecting the connection openings of the intake manifold to the cylinders of the engine.

Here, the restricted section 20 extends substantially in a plane parallel to the plane containing the external opening 14.

The embodiment shown in figures 4 and 5 differs from the previous one in that the intake manifold 10 'is intended to be connected to 3 cylinders. The same elements are designated by the same reference numerals appended with a prime “'”.

In the embodiment shown in figures 4 to 6 , the portion 16'a whose section continuously decreases is substantially frustoconical and asymmetrical ( figure 5 ). The shape of the restricted section 20 'differs from the shape of the restricted section of the previous embodiment in order to distribute the gas entering through the EGR line (not shown) to the 3 cylinders to which the intake manifold 10' is connected. Thus, the restricted section 20 'is substantially pear-shaped (see figures 4 and 6 ) and extends in two planes inclined with respect to each other, as visible on the figure 4 . The restricted section 20 thus has two rounded indentations, one of which has a greater radius on the side of the intake manifold connected to two cylinders of the engine and the other of smaller radius on the side of the intake manifold connected to the third cylinder of the engine. .

It will thus be understood that the restricted section 20 ′ may have a variable shape depending on the shape of the intake manifold and on the position of the engine cylinders connected to this intake manifold. It may thus have an oval, elliptical, crescent, pear-shaped, bone-like shape ( figure 7 ), ...

It will be noted that in general, whatever the shape of the passage, the latter is produced in a part of the wall of the intake manifold which has a greater thickness to allow the attachment of the exhaust pipe for recycling the gases.

As shown on figures 1 and 3 , the exhaust gas recirculation pipe 12 is fixed in the usual way by a flange 24 and two screws 26 passing through the flange 24 and screwed into the bores provided for this purpose of the intake manifold 10. A metal seal is arranged between flange 24 and intake manifold 10.

The invention has the advantage of integrating in one and the same part the intake manifold and a diffuser for the recycled exhaust gases. This makes it possible to simplify the mounting of the exhaust gas recirculation pipe on the intake manifold, but also to limit the risks of loss of the diffuser by disconnection. In addition, the diffusion of the gases is improved by the particular shape of the walls of the passage forming the diffuser.

Claims (8)

1. Metallic air intake manifold (10, 10') for supplying the cylinders of an internal combustion engine with air, said intake manifold (10, 10') having an external opening (14, 14') intended to be connected to a pipe (12) for recirculating the exhaust gases emitted by the engine, said external opening (14, 14') communicating with a passage (16, 16') passing through a wall (18, 18') of said intake manifold (10, 10') and opening into the latter, characterized in that said passage (16, 16') is shaped so as to diffuse a gas coming from the external opening (14, 14') into said intake manifold (10, 10'), said passage (16, 16') passing through the wall (18, 18') of the manifold having a portion (16a, 16'a) of symmetric or asymmetric and frustoconical or substantially frustoconical shape, the section of which decreases continuously from the external opening (14, 14') to a restricted section of elongate shape (20, 20'), its ends being directed towards the furthest cylinders to which the intake manifold is connected, in order to accelerate and direct a gas circulating in said passage (16, 16') in the direction of the engine cylinders to which said intake manifold is connected, the length of said restricted section of elongate shape extending substantially parallel to a line joining openings for connecting the intake manifold to the engine cylinders.
2. Air intake manifold (10, 10') according to Claim 1, characterized in that the passage (16, 16') has a portion (16b, 16'b) of flared shape between the restricted section (20, 20') and an internal end (17, 17') of said passage.
3. Air intake manifold (10, 10') according to Claim 2, characterized in that the portion (16b, 16'b) of flared shape has at least one shoulder (22, 22').
4. Air intake manifold (10, 10') according to any one of Claims 1 to 3, characterized in that the restricted section (20, 20') extends at least partially in a plane inclined relative to a plane containing the external opening (14, 14') of the passage.
5. Air intake manifold (10, 10') according to any one of Claims 1 to 4, characterized in that the restricted section (20, 20') has an oblong shape with rounded edges, for example chosen from an oval, an ellipse, a pear-like shape, a crescent-like shape, a shape with two parallel edges connected by rounded ends, a shape with two parallel edges connected by portions of a circle with a diameter greater than the distance separating the parallel edges, a combination of one or more of these shapes or any other oblong shape.
6. Air intake manifold (10, 10') according to any one of Claims 1 to 5, characterized in that the restricted section (20, 20') has shapes that are notched and rounded in the direction of at least one engine cylinder to which said intake manifold is connected.
7. Internal combustion engine comprising an air intake manifold (10, 10') according to any one of Claims 1 to 6 and a pipe (12) for recirculating the exhaust gases emitted by the engine, said pipe being connected to said external opening (14, 14') of said air intake manifold.
8. Motor vehicle comprising an internal combustion engine according to Claim 7.

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