EP3085913A1 - Device for purifying exhaust gases, exhaust line comprising said device - Google Patents

Abstract

The purification device comprises: a first purification member (20) comprising a first substrate (22) having a first perimeter; a second purification member (24) comprising a second substrate (26) having a second perimeter; the first and second purification members being arranged side by side, so that respective first and second surfaces (42, 44) of the first and second substrates are placed facing each other. The first surface (42) has a first width greater than 7% of the first perimeter, the second surface (44) having a second width greater than 7% of the second perimeter, the first and second surfaces having respective shapes co-adapted to such so that at least one of the first and second surfaces is separated at any point from the other of the first and second surfaces by a distance of less than 30 mm.

Description

The invention generally relates to exhaust gas purification devices.

• un premier organe de purification comportant un premier substrat de purification des gaz d'échappement, les gaz d'échappement circulant dans le premier substrat selon une première direction, le premier substrat présentant perpendiculairement à la première direction une première section ayant un premier périmètre ;
• un second organe de purification comportant un second substrat de purification des gaz d'échappement, les gaz d'échappement circulant dans le second substrat selon une seconde direction sensiblement opposée à la première direction, le second substrat présentant perpendiculairement à la seconde direction une seconde section ayant un second périmètre ;
• les premier et second organes de purification étant disposés côte-à-côte et sensiblement parallèlement l'un à l'autre, de telle sorte que des première et seconde surfaces respectives des premier et second substrats sont placées en vis-à-vis.

More specifically, the invention relates to a device for purifying the exhaust gases of a vehicle, the device comprising:

• a first purification member comprising a first exhaust gas purification substrate, the exhaust gas flowing in the first substrate in a first direction, the first substrate having a first section perpendicular to the first direction having a first perimeter;
• a second purification member comprising a second exhaust gas purification substrate, the exhaust gases flowing in the second substrate in a second direction substantially opposite to the first direction, the second substrate having perpendicularly to the second direction a second section; having a second perimeter;
• the first and second purification members being disposed side-by-side and substantially parallel to each other, so that respective first and second surfaces of the first and second substrates are placed facing each other.

Such purification devices with a U-shaped architecture are frequently used in vehicles with rear-exit engines. They are placed in the engine compartment.

The Figures 1 and 2 represent a U-shaped purification device according to the state of the art. The first and second substrates 2 and 4 are cylindrical blocks having, perpendicular to the first and second directions, circular sections. The outlet of the first purification member is connected to the inlet of the second purification member by a volume 6, formed of a bezel 8 and a cover 10. The bezel 8 is a plate having two orifices 12, 14 of sections circular, to which the first and second purification members are attached. The orifices 12 and 14 are delimited by collars, visible on the figure 1 .

The inlet of the first purification member is defined by an inlet cover 15, visible on the figure 1 .

The constraints on the size of the elements placed near the engine block are becoming more severe. In this context, the invention aims to provide a purification device which is more compact.

To this end, the invention relates to a purification device of the aforementioned type, the first surface present, perpendicular to the first direction, a first width greater than 7% of the first perimeter, the second surface having, perpendicular to the second direction, a second width greater than 7% of the second perimeter, the first and second surfaces having respective shapes co-adapted so that at least one of the first and second surfaces is separated at all points from the other of the first and second surfaces by a distance of less than 30 mm, preferably less than 25 mm.

The fact that the first and second substrates are co-adapted therefore makes it possible to bring the first and second surfaces closer to one another. This makes it possible to increase the compactness of the purification device. By co-adapted forms, it is meant here that the shapes of the first and second surfaces allow such approximation to occur, over at least 7% of the perimeter of the first substrate and at least 7% of the perimeter of the second substrate.

Thus, it is not only substantially linear areas of the two substrates that can be placed next to each other. On the contrary, the shapes of the first and second substrates are chosen so that the two substrates can be side by side on significant portions of their respective peripheries.

In the state of the art shown on the Figures 1 and 2 , the circular section of the first and second substrates does not bring them considerably closer to each other. Only strips of very small perimeter widths of the first and second substrates can be placed in close proximity to one another.

• les première et seconde surfaces, prises perpendiculairement respectivement aux première et seconde directions, ont en tout point un rayon de courbure supérieur à 25% du premier périmètre ;
• les première et secondes surfaces sont bombées l'une vers l'autre ;
• au moins l'une des première et seconde surfaces, prises perpendiculairement respectivement aux première et seconde directions, présente un rayon de courbure compris entre 0,5 * (P₁/2π) et 2* (P₁/2π), où P₁ est le premier périmètre ;
• l'une des première et secondes surfaces est concave et l'autre des première et secondes surfaces est convexe ;
• au moins l'une des première et seconde surfaces est plane ;
• le premier organe de purification comprend une première enveloppe externe avec une première paroi périphérique qui, considérée perpendiculairement à la première direction, entoure entièrement le premier substrat ;
• le second organe de purification comprend une second enveloppe externe avec une seconde paroi périphérique qui, considérée perpendiculairement à la seconde direction, entoure entièrement le second substrat ;
• les première et seconde parois périphériques étant distinctes l'une de l'autre ;
• les première et seconde parois périphériques sont entièrement séparées l'une de l'autre sur au moins 75% d'une longueur de la première ou de la seconde paroi périphérique, prises respectivement selon la première ou la seconde direction ;
• le dispositif de purification comprend des entretoises interposées entre les première et seconde parois périphériques ;
• le dispositif de purification comporte une paroi périphérique unique à contour fermé qui, considérée perpendiculairement à la première direction, entoure entièrement les premier et second substrats ;
• le premier organe de purification des gaz d'échappement comprend une première nappe en matière fibreuse, interposée entre le premier substrat et la paroi périphérique unique, la première nappe, considérée perpendiculairement à la première direction, entourant entièrement le premier substrat ;
• le second organe de purification des gaz d'échappement comprend une seconde nappe en matière fibreuse, interposée entre le second substrat et la paroi périphérique unique, la seconde nappe, considérée perpendiculairement à la seconde direction, entourant entièrement le second substrat ;
• le dispositif comprend au moins un joint d'étanchéité en contact à la fois avec la première nappe en matière fibreuse, avec la seconde nappe en matière fibreuse et avec la paroi périphérique unique ;
• le dispositif de purification comprend :
  • une nappe périphérique en matière fibreuse interposée entre d'une part les premier et second substrats et d'autre part la paroi périphérique unique, la nappe périphérique, considérée perpendiculairement à la première direction, entourant entièrement les premier et second substrats ;
  • une nappe intermédiaire en matière fibreuse interposée entre les premier et second substrats ;
  • le premier organe de purification comprend une première enveloppe externe délimitant une première entrée de gaz d'échappement et une première sortie de gaz d'échappement ;
  • le second organe de purification comprend une seconde enveloppe externe délimitant une seconde entrée de gaz d'échappement et une seconde sortie de gaz d'échappement ;
  • le dispositif de purification des gaz d'échappement comprenant en outre un volume raccordant fluidiquement la première sortie à la seconde entrée ou la seconde sortie à la première entrée, le volume étant délimité par un couvercle rapporté directement sur les première et seconde enveloppes externes.

The purification device may also have one or more of the following characteristics considered individually or in any technically possible combination:

• the first and second surfaces, taken perpendicular respectively to the first and second directions, have in all respects a radius of curvature greater than 25% of the first perimeter;
• the first and second surfaces are curved towards each other;
• at least one of the first and second surfaces, taken perpendicular respectively to the first and second directions, has a radius of curvature between 0.5 * (P ₁ / 2π) and 2 * (P ₁ / 2π), where P ₁ is the first perimeter;
• one of the first and second surfaces is concave and the other of the first and second surfaces is convex;
• at least one of the first and second surfaces is planar;
• the first purification member comprises a first outer envelope with a first peripheral wall which, viewed perpendicularly to the first direction, completely surrounds the first substrate;
• the second purification member comprises a second outer envelope with a second peripheral wall which, viewed perpendicularly to the second direction, completely surrounds the second substrate;
• the first and second peripheral walls being distinct from one another;
• the first and second peripheral walls are entirely separated from each other by at least 75% of a length of the first or second peripheral wall, taken respectively in the first or second direction;
• the purification device comprises spacers interposed between the first and second peripheral walls;
• the purification device comprises a single peripheral wall with a closed contour which, considered perpendicular to the first direction, completely surrounds the first and second substrates;
• the first exhaust gas purification member comprises a first sheet of fibrous material interposed between the first substrate and the single peripheral wall, the first sheet, considered perpendicular to the first direction, completely surrounding the first substrate;
• the second exhaust gas purification member comprises a second ply of fibrous material interposed between the second substrate and the single peripheral wall, the second ply, considered perpendicular to the second direction, completely surrounding the second substrate;
• the device comprises at least one seal in contact with both the first web of fibrous material, the second web of fibrous material and the single peripheral wall;
• the purification device comprises:
  • a peripheral layer of fibrous material interposed between on the one hand the first and second substrates and on the other hand the single peripheral wall, the peripheral layer, considered perpendicular to the first direction, completely surrounding the first and second substrates;
  • an intermediate web of fibrous material interposed between the first and second substrates;
  • the first purification member comprises a first outer envelope delimiting a first exhaust gas inlet and a first exhaust gas outlet;
  • the second purification member comprises a second outer envelope delimiting a second exhaust gas inlet and a second exhaust gas outlet;
  • the exhaust gas purification device further comprising a volume fluidly connecting the first output to the second input or the second output to the first input, the volume being delimited by a cover attached directly to the first and second outer shells.

According to another aspect, the invention relates to an exhaust line comprising a purification device having the above characteristics.

• la figure 1 est une représentation schématique en coupe, d'un dispositif de purification conforme à l'état de la technique ;
• la figure 2 est une vue de face du dispositif de purification de la figure 1, le couvercle n'étant pas représenté pour laisser apparaitre la lunette ;
• la figure 3 est une vue en perspective d'un dispositif conforme à un premier mode de réalisation de l'invention ;
• la figure 4 est une vue partielle en coupe du dispositif de la figure 3 ;
• la figure 5 est une vue partielle, en perspective, du dispositif de la figure 3, le couvercle n'étant pas représenté ;
• la figure 6 est une vue de face, par l'arrière, du dispositif de la figure 3, les couvercles définissant l'entrée et la sortie du dispositif n'étant pas représentés ;
• la figure 7 est une vue de face, similaire à celle de la figure 6, d'un dispositif de purification conforme à un second mode de réalisation de l'invention ;
• la figure 8 est une vue agrandie d'une zone d'un dispositif de purification conforme à une variante du second mode de réalisation ;
• la figure 9 est une vue similaire à celle de la figure 8 pour une autre variante de réalisation du second mode de réalisation de l'invention ;
• la figure 10 et la figure 11 sont des vues de face illustrant un autre aspect de l'invention ;
• la figure 12 est une vue en perspective d'un dispositif de purification illustrant encore un autre aspect de l'invention ;
• la figure 13 est une vue en coupe, partielle, du dispositif de purification de la figure 12,
• la figure 14 est une vue en perspective, similaire à la figure 12, le couvercle externe n'étant pas représenté pour laisser apparaitre le cône interne ;
• la figure 15 est une vue de côté du dispositif de purification de la figure 12 avec une coupe partielle ; et
• la figure 16 est une vue agrandie d'un détail de la figure 13, illustrant une variante de réalisation de l'invention.

Other features and advantages of the invention will become apparent from the detailed description given below, for information only and in no way limitative, with reference to the appended figures, among which:

• the figure 1 is a schematic sectional representation of a purification device according to the state of the art;
• the figure 2 is a front view of the purification device of the figure 1 the lid is not shown to reveal the bezel;
• the figure 3 is a perspective view of a device according to a first embodiment of the invention;
• the figure 4 is a partial sectional view of the device of the figure 3 ;
• the figure 5 is a partial view, in perspective, of the device of the figure 3 the lid is not shown;
• the figure 6 is a front view, from the back, of the device of the figure 3 , the covers defining the input and the output of the device not being represented;
• the figure 7 is a front view, similar to that of the figure 6 , a purification device according to a second embodiment of the invention;
• the figure 8 is an enlarged view of an area of a purification device according to a variant of the second embodiment;
• the figure 9 is a view similar to that of the figure 8 for another variant embodiment of the second embodiment of the invention;
• the figure 10 and the figure 11 are front views illustrating another aspect of the invention;
• the figure 12 is a perspective view of a purification device illustrating yet another aspect of the invention;
• the figure 13 is a partial sectional view of the purification device of the figure 12 ,
• the figure 14 is a perspective view, similar to the figure 12 the outer cover is not shown to reveal the inner cone;
• the figure 15 is a side view of the purification device of the figure 12 with partial cut; and
• the figure 16 is an enlarged view of a detail of the figure 13 , illustrating an alternative embodiment of the invention.

The device 1 represented on the figure 3 is intended for the purification of the exhaust gases of a vehicle, typically of a motor vehicle equipped with a heat engine such as a car or a truck. The purification device 1 is intended to be integrated in an exhaust line. It is connected upstream to a collector sensing the exhaust gas leaving the combustion chambers of the engine, and downstream to a cannula for releasing purified exhaust gas into the atmosphere. The collector and the cannula are not represented. Other equipment is generally interposed between the purification device and the collector, for example a turbo compressor. Still other equipment, such as silencers, are interposed between the purification device and the cannula.

The purification device 1 comprises an exhaust gas inlet 16, fluidly communicating with the upstream part of the exhaust line, and an exhaust gas outlet 18, fluidly communicating with the downstream part of the exhaust line. .

Upstream and downstream are meant here relative to the direction of normal exhaust gas flow.

• un premier organe de purification 20, comportant un premier substrat de purification des gaz d'échappement 22 (figure 4), les gaz d'échappement circulant dans le premier substrat 22 selon une première direction D1 représentée sur la figure 4 ;
• un second organe de purification 24, comportant un second substrat 26 de purification des gaz d'échappement, les gaz d'échappement circulant dans le second substrat selon une seconde direction D2 (figure 4) sensiblement opposée à la première direction.

The purification device comprises:

• a first purification unit 20, comprising a first exhaust purification substrate 22 ( figure 4 ), the exhaust gas flowing in the first substrate 22 in a first direction D1 shown in FIG. figure 4 ;
• a second purification unit 24, comprising a second exhaust gas purification substrate 26, the exhaust gases flowing in the second substrate in a second direction D2 ( figure 4 ) substantially opposite the first direction.

The first and second directions D1, D2 are parallel and opposite to each other. Alternatively, they are slightly inclined relative to each other.

In the following description, the longitudinal direction will be called a direction parallel to, or substantially parallel to, the first and second directions.

The first purification member 20 further comprises a first outer casing 28 delimiting a first exhaust gas inlet 30 in the first purification unit, and a first exhaust gas outlet 32 out of the first purification unit.

Similarly, the second purification member 24 comprises a second outer envelope 34 delimiting a second exhaust gas inlet 36 inside the second purification member, and a second outlet 38 of exhaust gas out of the second purification member.

The first and second substrates 22, 26 are housed inside the first and second envelopes 28, 34 respectively.

The purification device 1 further comprises a volume 40, fluidly connecting the first outlet 32 to the second inlet 36.

As shown in the figures, the first and second purification members 20, 24 are arranged side by side and substantially parallel to each other. By this is meant that the first and second purification members have respective central axes parallel to one another, these central axes being typically longitudinal, that is to say parallel to the first and second directions.

The central axis of the first purification member is defined as the axis passing through the centers of all the straight sections of the first purification member, these straight sections being taken perpendicularly to the first direction. Similarly, the central axis of the second purification member corresponds to the axis passing through the centers of all the straight sections of the second purification member, these straight sections being taken perpendicularly to the second direction.

The first and second purification members are arranged side by side, in the sense that first and second respective surfaces 42, 44 of the first and second substrates 22, 26 are placed facing each other, c that is to say one face to the other.

According to one aspect of the invention, the first substrate 22 has, perpendicular to the first direction, a first section having a first perimeter, the first surface 42 having, perpendicular to the first direction, a first width of between 7% and 50% the first perimeter.

On the other hand, the second substrate 26 has perpendicularly to the second direction a second section having a second perimeter, the second surface 44 having, perpendicular to the second direction, a second width of between 7% and 50% of the second perimeter.

When the first substrate 22 has a constant cross section perpendicular to the first direction, the first perimeter corresponds to the perimeter of said section.

Likewise, the second substrate typically has a constant cross-section along the second direction. In this case, the second perimeter corresponds to the perimeter of this cross-section.

It is also possible that the second substrate has straight sections that vary slightly along the second direction. In this case, we consider second perimeter the average of the perimeters of all the straight sections of the second substrate.

The first width corresponds to the width of the first surface 42 taken perpendicular to the first direction.

The first width is taken along the perimeter of the first substrate 22.

Similarly, the second width corresponds to the width of the second surface 44 taken perpendicular to the second direction, following the perimeter of the second substrate 26.

The first width is greater than 7% of the first perimeter, preferably greater than 10% of the first perimeter, and even more preferably greater than 15% of the first perimeter. It is less than 50% of the first perimeter, which means that the first substrate 22 is not entirely housed in the second substrate 26, but is placed next to it.

Similarly, the second width is greater than 7% of the second perimeter, preferably greater than 10% of the second perimeter and more preferably greater than 15% of the second perimeter. It is less than 50% of the second perimeter, which means that the second substrate 26 is not entirely housed in the first substrate 22.

The first surface 42 has for example a constant width when following said surface 42 in the first direction. The first width then corresponds to said width. Alternatively, the first surface has a variable width when following the first surface parallel to the first direction. The width of the first surface considered in section perpendicular to the first direction is then chosen as the first width.

Similarly, the second surface 44 may have a constant width when it follows in the second direction, said width then corresponding to the second width. Alternatively, the second surface has variable widths when followed in the second direction. The second width is then considered as the average of the widths of the second surface considered in section perpendicular to the second direction.

The first and second surfaces 42, 44 have respective shapes co-adapted such that at least one of the first and second surfaces 42, 44 is separated at all points from the other of the first and second surfaces 42, 44 by a distance less than 30 mm, preferably less than 25 mm, a distance between the envelopes 28 and 34 less than 10 mm, preferably less than 5 mm.

The first and second surfaces 42, 44 extend longitudinally substantially the entire length respectively of the first and second substrates 22, 26.

Thus, in the example shown on the figures 3 and 4 each point of the first surface 42 is placed opposite a point of the second surface 44, but the opposite is not true, because the first substrate 22 is shorter than the second substrate 26.

Alternatively, the second substrate 26 is shorter than the first substrate 22, each point of the second surface thus being placed opposite a point of the first surface.

According to yet another embodiment, the first and second substrates are of the same length, each point of the first surface thus being placed opposite a point of the second surface.

The distance from one point of the first surface 42 to the second surface is taken by considering a direction perpendicular to the first surface and passing through said point.

In an exemplary embodiment shown on the Figures 3 to 8 , the first and second surfaces 42, 44 taken perpendicular respectively to the first and second directions, have in all respects a radius of curvature typically greater than 25% of the first perimeter. In other words, the first and second surfaces 42, 44 each have a curvature sufficiently small that they can be placed close to each other at all points.

In this case, the first surface 42 is preferably bulged towards the second surface 44, and conversely the second surface 44 is preferably curved towards the first surface 42. However, it is conceivable that the first surface 42 is concave towards the second surface. 44, and vice versa.

According to another variant not shown, at least one of the first and second surfaces 42, 44 is flat, and preferably the first and second surfaces 42, 44 are both flat.

According to an alternative embodiment represented on the figure 9 one of the first and second surfaces 42, 44, taken perpendicular respectively to the first and second directions, has a radius of curvature between 0.5 x (P ₁ / 2π) and 2 x (P ₁ / 2π) where P ₁ is the first perimeter, preferably between 0.75 x (P ₁ / 2π) and 1.25 x (P ₁ / 2π).

In other words, at least one of the first and second surfaces 42, 44 has a pronounced curvature.

Typically, and as illustrated on the figure 9 the first and second surfaces 42, 44 both have pronounced radii of curvature close to or substantially equal to each other.

In this case, and as shown on the figure 9 one of the two surfaces 42, 44 is concave. The other of the two surfaces is convex, and is engaged in the concave surface. The concave surface and the convex surface are substantially complementary to one another.

In the exemplary embodiment illustrated on the figure 5 , the first envelope 28 comprises a first peripheral wall 46 which, considered perpendicular to the first direction, completely surrounds the first substrate 22. Similarly, the second envelope 34 comprises a second peripheral wall 48 which, considered perpendicular to the second direction completely surrounds the second substrate 26. The first and second peripheral walls are distinct from each other. They did not come together with each other. They are tubular.

More specifically, the first peripheral wall 46 comprises a first central section 50 in which the first substrate 22 is housed, and a first downstream end 52 defining the first exhaust gas outlet 32. The first downstream end 52 is integral with the first downstream section 50, and extends the latter in the first direction, towards the volume 40.

Similarly, the second peripheral wall 48 comprises a second central section 54 in which the second substrate 26 is housed, and a second upstream end 56 defining the second inlet 36 of exhaust gas.

As visible especially on figures 3 and 4 the first and second peripheral walls 46, 48 are entirely separated from each other by at least 75% of the longitudinal length of the first or second peripheral wall.

In the example shown, the first peripheral wall is longitudinally shorter than the second peripheral wall, the first and second peripheral walls 46, 48 thus being entirely separated over at least 80% of the longitudinal length of the first peripheral wall.

More specifically, the first downstream end 52 of the first peripheral wall is in contact with the second upstream end 56 of the second peripheral wall, but the first and second central sections 50, 54 are entirely separated from each other. They are never in direct contact with each other

The gap 58 between the two central sections 50, 54 allows the peripheral walls to expand freely at high temperature.

In an alternative embodiment shown on the figure 3 , the purification device comprises spacers 60, interposed between the first and second peripheral walls, so as to maintain a spacing between the first and second central sections 50, 54.

The spacers 60 may have any suitable shape: metal tab, rod extending parallel to the first and second directions etc.

The variant embodiment of the Figures 3 to 6 , with two peripheral walls 46, 48 that are distinct and independent of one another, are particularly suitable in the case where the first and second surfaces 42, 44 facing each other have high radii of curvature.

As illustrated in the figures, the first central section 50 has, in section perpendicular to the first direction, a shape substantially corresponding to that of the section of the first purification member 22. A gap 62 of substantially constant thickness separates the first substrate 22 of the first central section 50. A mat of a fibrous material 64 is interposed between the first substrate 22 and the first central section 50. This mattress makes it possible to maintain the first substrate 22 radially and axially in position with respect to the first envelope. Similarly, the second central section 54 has, considered in section perpendicular to the second direction, a shape substantially corresponding to that of the second substrate 26. A mattress 66 is interposed between the second substrate 26 and the second central section 54.

So, as visible on the figure 6 the first and second central sections 50, 54 also have respective surfaces 68, 70 facing each other, and separated from each other by the gap 58. one of the surfaces 68, 70 is separated at any point from the other by a distance of less than 10 mm, preferably less than 5 mm.

According to a second embodiment shown on the Figures 7 to 9 , the purification device 1 comprises a single peripheral wall 72 with a closed contour which, considered perpendicular to the first direction, completely surrounds the first and second substrates 22, 26.

The single peripheral wall 72 includes a first zone 74 partially surrounding the first substrate 22, and a second zone 76 partially surrounding the second substrate 26. The first and second zones constitute the first and second peripheral walls 46, 48 of the first and second outer envelopes 28, 34.

In the variant embodiment of the figure 8 the first purification member 20 comprises a first ply 78 of fibrous material interposed between the first substrate 22 and the single peripheral wall 72. The first ply 78, considered perpendicular to the first direction, completely surrounds the first substrate 22. A zone 80 of this web is interposed between the first substrate 22 and the second substrate 26. The web 78 is provided to retain the first substrate 22 in position relative to the single peripheral wall 72.

Furthermore, the second purification member 24 comprises a second ply 82 of fibrous material, interposed between the second substrate 26 and the single peripheral wall 72. The second ply 82, considered perpendicular to the second direction, surrounds entirely the second substrate 26. An area 84 of the second web is interposed between the first and second substrates. Thus, the first and second substrates are separated from each other by the zone 80 of the first ply and by zone 84 of the second ply, the two zones being stacked one on the other. The second ply 82 is provided to hold the second substrate 26 in position relative to the single peripheral wall 72.

At least one seal 86 is preferably disposed in contact with both the first fibrous web 78, the second fibrous web 82 and the single peripheral wall 72. Typically, two seals 86 are arranged, on both sides of the two substrates, in the same plane as the zones 80 and 84. These seals prevent leakage of exhaust gas between the fibrous material plies and the peripheral wall. They also make it possible to press the first and second plies 78, 82 against the first and second substrates 22, 26, along the edges of these substrates.

The seals 86 are typically longitudinal rods made of a fibrous material.

Alternatively, and as shown on the figure 7 , the purification device comprises a peripheral layer 88 of fibrous material interposed between the first and second substrates 22, 26 on the one hand and the single peripheral wall 72 on the other hand. The peripheral layer 88, considered perpendicular to the longitudinal direction, completely surrounds the first and second substrates 22, 26.

Furthermore, the purification device 1 further comprises an intermediate sheet 90 of fibrous material, interposed between the first and second substrates 22, 26. More specifically, the intermediate sheet 90 is interposed between the first and second surfaces 42, 44. extends over the entire width of the surfaces 42 and 44. The intermediate web 90 divides the volume delimited internally by the peripheral layer 88 in two parts sealed against each other for the exhaust gas.

The first substrate 22 is housed in one of the two parts, the second substrate 26 in the other part.

The embodiment of the Figures 7 to 9 , with a single peripheral wall 72, is particularly well suited to the embodiment of the invention where the first and second surfaces 42, 44 have significant curvatures, as illustrated in FIG. figure 9 .

According to another aspect of the invention, independent of the first, the volume 40 is delimited by a lid 92 in the form of a cup, attached directly to the first and second outer shells 28, 34.

Specifically, the cover 92 has a bottom 94 and a peripheral edge 96 with a closed contour projecting from the bottom 94, the peripheral edge 96 being directly attached to the first and second outer shells 28, 34.

Here is meant by directly attached or reported the fact that the lid is not attached to a bezel-shaped piece such as the piece 8 shown on the figure 1 , this being in turn attached to the first and second envelopes 28, 34. Due to the absence of a spectacle-shaped part, it becomes possible to bring the first and second purification members 20, 24 one of them closer together. on the other and thus make the purification device much more compact. The lid is in turn smaller. The disappearance of the bezel, and the fact that the lid is smaller, to lighten the purification device and reduce the thermal inertia of this device. In addition, the number of connections is reduced, which makes it possible to reduce the number of weld seams.

The dimensions of the spectacle-shaped part, in particular the separation between the inlet and the outlet, are constrained, in the state of the art of the Figures 1 and 2 by providing enough material to form the necks surrounding the inlet and the outlet.

Typically, the bottom 94 of the lid is flat. The peripheral edge 96 has a tubular shape. Alternatively, the bottom 94 has a more complex shape, for example when an ammonia injection device or an ammonia precursor is mounted on the lid.

More specifically, the first and second purification members 20, 24 together define, at a end facing the volume 40, a continuous outer end surface 98, with a closed contour, the peripheral edge 96 of the lid being also continuous, closed contour. The peripheral edge 96 is directly attached to the outer end surface 98.

The outer end surface 98 is tubular. The outer end surface 98 is defined by the first downstream end 52 of the first envelope and the second upstream end 56 of the second envelope, without possibly the areas where they are pressed against each other.

Thus, in the exemplary embodiment of Figures 3 to 6 , the first downstream end 52 and the second upstream end 56 are part of two walls distinct from each other, the first downstream end 52 and the second upstream end 56 being contiguous to one another so as to define a closed contour continuous surface.

In the embodiment of Figures 7 to 9 the outer end surface 98 corresponds to the end of the single peripheral wall 72 facing the volume 40.

The peripheral edge 96 ends, opposite the bottom 94, by a free edge 100, with a closed contour, of shape conjugate with that of the outer end surface 98. The free edge 100 is pressed against the surface of the outer surface. outer end 98 and rigidly attached thereto, for example welded thereto.

The outer end surface 98 is engaged within the free edge 100.

Thus, the peripheral edge 96, and more precisely its free edge 100, internally delimits an opening 101 having, perpendicular to the first direction, a given surface. The first outlet 32 has a first surface perpendicular to the first direction. The second inlet 36 has a second surface perpendicular to the second direction.

The sum of the first and second surfaces is substantially equal to the given area.

Typically, the free edge 100 has a shape obtained by circulating a generatrix of determined shape, along a closed contour guide curve extending in a plane substantially perpendicular to the longitudinal direction. The generator has for example the shape of a line segment of longitudinal orientation. Alternatively, it has the shape of a line segment slightly inclined with respect to the longitudinal direction.

The closed contour guideline can have any kind of shape. It is for example oval with or without bending in the central part, elliptical or any other shape.

In the embodiment of Figures 3 to 6 , wherein the first and second peripheral walls 46, 48 are distinct from one another, the first downstream end 52 and the second upstream end 56 advantageously have first and second respective sections 102 and 104 pressed against each other. other, as visible on the Figures 5 and 6 .

The first and second sections 102, 104 are advantageously straight, that is to say rectilinear. They typically extend parallel to the first and second surfaces 42, 44. If the first perimeter length is referred to as the perimeter length of the first downstream end, and the second perimeter length is the length of the perimeter of the second upstream end, then the first and second sections 102, 104 respectively extend over at least 15% of the first perimeter length and at least 10% of the second perimeter length, respectively.

Preferably, first and second sections 102, 104 respectively extend over at least 20% of the first perimeter length and at least 15% of the second perimeter length respectively.

The first and second sections 102, 104 extend longitudinally over less than 25% of the longitudinal length of the first and / or second peripheral walls 46, 48.

As visible on figures 3 and 4 , the first downstream end 52 and the second upstream end 56 have, perpendicular to the first and second directions, first and second sections greater than those of the first and second central sections 50, 54.

In other words, the first downstream end 52 projects slightly outwardly of the first purification member relative to the first central section 50, and this over all or substantially all of its periphery. Similarly, the second upstream section 56 projects outwardly from the second purification member relative to the second central section 54, and this over all or substantially all of its periphery.

The first downstream section is separated from the first central section by an outgoing shoulder 106. The second upstream end 56 is separated from the second central section 54 by an outgoing shoulder 108.

This arrangement makes it possible to create the gap 58 between the central sections 50 and 54.

Due to this widening of sections, the first downstream end 52 and the second upstream end 56 do not participate in the blocking in position of the first and second substrates through the fibrous webs 64 and 66. This maintenance is carried out exclusively at level of the central sections 50 and 54.

As visible on Figures 10 and 11 , it is possible to create the first and second sections 102, 104 at the first downstream end 52 and the second upstream end 56 regardless of the shape of the first and second substrates 22, 26.

In the exemplary embodiment of Figures 10 and 11 , the first and second substrates 22, 26 are of circular sections, considered perpendicular respectively to the first and second directions. Alternatively, the first and / or second substrate has an oval shape or a race-track type shape, with two substantially flat sides or large radius of curvature, substantially parallel to one another, connected by arcs of smaller radius of curvature.

The first central section 50 has a cylindrical shape with circular sections. The first downstream end 52 comprises a portion 110 in an arc of a circle, extending over at least 60% of the periphery of the first downstream end, in addition to the straight section 102. The straight section 102 extends in a substantially tangent plane to the first substrate 22. It is connected to the portion 110 by flanks 112 connecting at the straight section 102 in a direction between the perpendicular to the straight section 102 and the tangent to the portion 110.

Straight section 102 is typically formed only at the ends of the canning.

Similarly, the second central section 54 has a cylindrical shape, of circular section adapted to receive the second substrate 26. The second upstream end 56 has an arcuate portion 114, extending over at least 60% of the periphery of the the second upstream end, in addition to the right section 104. The straight section 104 extends in a plane tangential to the second substrate 26. The straight section 104 is connected to the portion 114 by flanks 116 connecting to the straight section 104 in a manner direction between the perpendicular to the section 104 and the tangent to the portion 114.

According to yet another aspect, illustrated on the Figures 12 to 16 , the purification device 1 comprises an outer cover 118 and an inner cone 120 housed in the outer cover 118.

The first and second peripheral walls 46, 48 respectively have an upstream first end 122 delimiting the first exhaust gas inlet 30, and a second downstream end 124 delimiting the second exhaust gas outlet 38. The outer cover 118 is of size and shape chosen so as to cover both the first inlet 30 and the second outlet 38. This means that the first upstream end 122 and the second downstream end 124 are fully housed in the outer cover 118. In a variant not shown, the outer cover 118 is housed in the first upstream end 122 and in the second downstream end 124.

The inlet 16 and the outlet 18 of exhaust gas are formed in the outer cover 118.

The inner cone 120 has an outlet end 126 covering only the first inlet 30, and an inlet end 128 sealingly connected to the inlet 16.

More specifically, the outlet end 126 is housed in the first upstream end 122 or conversely the first upstream end 122 is housed in the outlet end 126.

The outer cover 118 has a generally cup-like shape, with a bottom 130 in which the inlet 16 and the outlet 18 are formed, and a side wall 132 extending around the bottom 130, and projecting from one side of the The side wall 132 is of closed contour, and protrudes longitudinally towards the first and second peripheral walls 46, 48.

As shown in the figures, the first and second peripheral walls 46, 48 have substantially the same length longitudinally. The first upstream end 122 and the second downstream end 124 thus together define another continuous external surface 134, closed contour, to which the side wall 132 is directly fixed.

The inlet 16 and the outlet 18 are delimited by necks 136 and 138 projecting outwardly from the purification device. The necks 136 and 138 protrude from the bottom 130 longitudinally on a side opposite to the side wall 132.

The inlet 16 is mechanically connected directly to the upstream equipment 140 ( figure 13 ).

More specifically, the upstream equipment 140 has an exhaust gas outlet 142, possibly extended by an exhaust gas circulation duct. The inlet 16 is mechanically connected either directly to the exhaust gas outlet 142, or directly to the duct. The neck 136 is rigidly fixed to the upstream equipment 140. For example, it is welded to a bicone 143 of the type shown in FIG. figure 16 it is itself connected to the upstream equipment 140, typically by a V-shaped collar. In a variant, the neck 136 is directly connected to a cone-flange of the upstream equipment 140, typically by a V-shaped collar. represented on the figure 13 the inlet 16 is fixed to the upstream equipment 140 by means of a flange 144.

Thus, at least the outer cover 118 is mechanically connected directly to the upstream equipment 140.

According to a first variant embodiment, the internal cone 120 is mechanically connected to the upstream equipment 140 only via the outer cover 118, typically by its inlet end 128. This situation is represented on the Figures 12 to 15 .

In other words, the stresses and stresses transmitted between the purification device and the upstream equipment 140 are transmitted mainly through the outer cover 118. These efforts pass especially, or even exclusively, through the connection between the outer cover 118 and the upstream equipment 140.

As a result, the outer cover 118 is made of a relatively thicker material, for example of thickness between 1 mm and 2 mm. The cover 118 is for example made of stainless steel, for example in 1.4509, 1.4510, 1.4512 or 1.4301.

The internal cone 120, because it does not take up effort, is made of a relatively less thick material than the outer cover 118, for example of thickness between 0.5 mm and 1 mm. For example, the inner cone 120 is made of stainless steel, for example 1.4509, 1.4510 or 1.4301.

In a second variant embodiment, illustrated on the figure 16 , the inner cone 120 is connected to the upstream equipment 140 with the outer cover 118. In other words, a single link 145 doubles, secures the inner cone 120 and the outer cover 118 to the upstream equipment 140.

This single link 145 is for example a weld. In the example shown, it secures the inner cone 120 and the outer cover to the bicone 143, the latter being connected to the upstream equipment 140.

As described above, because the outer cover 118 is made of a relatively thicker material, most of the effort will be transmitted between the purification device and the upstream equipment 140 via the outer cover 118. It is thus possible to realize the inner cone 120 in a relatively less thick material. The materials and the thicknesses of the outer cover 118 and the inner cone 120 are typically those described by the first embodiment.

As visible especially on the figure 13 , the inner cone 120 has a section widening from the inlet end 128 to the outlet end 126. The outlet end 126 is rigidly attached, in a sealed manner, to the first end upstream 122. It has for example an inner section complementary to the outer section of the first upstream end 122, the first upstream end 122 being engaged in the outlet end 126 of the inner cone.

The inlet end 128 of the inner cone is engaged in the neck 136. It is rigidly fixed to the neck 136 by any suitable means. Typically, the inlet end 128 has an outer section of complementary shape to the inner section of the neck 136. It is fixed for example by a weld line (not shown) to the inner surface of the neck 136. Alternatively, it is fitted without play, which contributes to the absence of force transmission through the internal cone.

Moreover, as visible on the figure 13 , the inner cone 120 and the outer cover 118 delimit between them a space 146 extending over the entire periphery of the inner cone 120 and fluidly communicating with the outlet 18. Thus, the exhaust gases leaving the second purification member 24 by the second outlet 38 will circulate around the internal cone 120, in the space 146, before being discharged through the outlet 18.

The arrangement described above has many advantages. Making the inner cone 120 of a thin material reduces the weight and thermal inertia of the purification device. Moreover, the fact that space 146 allows the circulation of exhaust gas leaving the second purification member around the inner cone 120, allows a rapid temperature rise of the inner cone 120, since this cone is exposed to the exhaust gas both by its inner surface and by its outer surface. Thus, in the case where the first and / or second substrate must reach a minimum temperature for the exhaust gas depollution is effective, this temperature is reached faster.

The first and second substrates may be of any type suitable for the purification of the exhaust gases. For example, for gasoline engines, the first substrate is a three-way catalyst and the second substrate is another three-way catalyst, or a particulate filter. For diesel engines, the first substrate is for example an oxidation catalyst, and the second substrate is for example a particulate filter. Alternatively, the first substrate is a PNA (Passive NOx Absorber, or passive NOx absorber) or a NOx trap (LNT Lean Nox Trap), and the second substrate is a particulate filter, or is a SCR type catalyst (Selective Catalytic reduction or selective catalytic reduction) or a catalytic filter SCRF type (Selective Catalytic Reduction Filter or selective catalytic reduction filter), or a SCRF type catalyst filter followed by a catalyst SCR type. In the case where the second substrate comprises an SCR type catalyst or an SCRF, a mixing device is provided in the volume 40, preferably. In this case, the purification device comprises a device for injecting a nitrogen oxide reducing product such as ammonia or an ammonia precursor, arranged to perform the injection upstream of the mixing device. The injection is typically carried out in volume 40. The injected product is for example the product sold under the trade name Adblue, or an aqueous solution of urea, or else ammonia gas (ASDS technology).

It should be noted that the first and second substrates 22, 26 do not necessarily occupy all the volume delimited internally by the first and second envelopes. As illustrated on the figure 15 one and / or the other of the substrates may occupy only a part of the longitudinal length of the first and / or the second envelope. The free volume is then likely to be used for the implantation of a device for injecting a nitrogen oxide reducing product, or a mixer, or any other suitable device.

Claims (15)

Device for purifying the exhaust gases of a vehicle, the device (1) comprising: a first purification element (20) comprising a first exhaust gas purification substrate (22), the exhaust gases flowing in the first substrate (22) in a first direction (D1), the first substrate (22); ) having perpendicularly to the first direction a first section having a first perimeter; a second purification member (24) comprising a second exhaust gas purification substrate (26), the exhaust gases flowing in the second substrate (26) in a second direction (D2) substantially opposite to the first direction; (D1), the second substrate (26) having perpendicularly to the second direction a second section having a second perimeter; the first and second purification members (20, 24) being arranged side by side and substantially parallel to each other, so that respective first and second first and second surfaces (42, 44) of the first and second substrates (22, 26) are placed facing each other;
characterized in that the first surface (42) has, perpendicular to the first direction (D1), a first width greater than 7% of the first perimeter, the second surface (44) having, perpendicular to the second direction (D2), a second width greater than 7% of the second perimeter, the first and second surfaces (42, 44) having respective shapes co-adapted such that at least one of the first and second surfaces (42, 44) is separated into any other point of the first and second surfaces (42, 44) by a distance less than 30 mm, preferably less than 25 mm. Purification device according to claim 1, characterized in that the first and second surfaces (42, 44), taken perpendicular respectively to the first and second directions (D1, D2), have a radius of curvature greater than 25% in all respects. first perimeter. Purification device according to claim 1 or 2, characterized in that the first and second surfaces (42, 44) are curved toward one another. Purification device according to claim 1, characterized in that at least one of the first and second surfaces (42, 44), taken perpendicular to the first and second directions (D1, D2) respectively, has a radius of curvature between 0.5 * (P ₁ / 2π) and 2 * (P ₁ / 2π), where P ₁ is the first perimeter. Purification device according to one of Claims 1 to 4, characterized in that one of the first and second surfaces (42, 44) is concave and the other of the first and second surfaces (42, 44) is convex. Purification device according to claim 1, characterized in that at least one of the first and second surfaces (42, 44) is flat. Purification device according to one of the preceding claims, characterized in that : the first purification member (20) comprises a first outer envelope (28) with a first peripheral wall (46) which, viewed perpendicular to the first direction (D1), completely surrounds the first substrate (22); the second purification member (24) comprises a second outer envelope (34) with a second peripheral wall (48) which, considered perpendicular to the second direction (D2), completely surrounds the second substrate (26); the first and second peripheral walls (46, 48) being distinct from one another. Purification device according to claim 7, characterized in that the first and second peripheral walls (46, 48) are entirely separated from each other by at least 75% of a length of the first or second wall device (46, 48), respectively taken in the first or second direction (D1, D2). Purification device according to claim 8, characterized in that the purification device (1) comprises spacers (60) interposed between the first and second peripheral walls (46, 48). Purification device according to any one of 1 to 6, characterized in that the purification device (1) comprises a single peripheral wall (72) with a closed contour which, considered perpendicular to the first direction (D1), completely surrounds the first and second substrates (22, 26). Purification device according to claim 10, characterized in that : the first exhaust gas purification member (20) comprises a first ply (78) of fibrous material interposed between the first substrate (22) and the single peripheral wall (72), the first ply (78), considered perpendicular to the first direction (D1), completely surrounding the first substrate (22); the second exhaust gas purification member (24) comprises a second fibrous material ply (82) interposed between the second substrate (26) and the single peripheral wall (72), the second ply (82) being considered perpendicular to the second direction (D2), completely surrounding the second substrate (26). Purification device according to claim 11, characterized in that it comprises at least one seal (86) in contact with both the first ply (78) of fibrous material and the second ply (82) of material fibrous and with the single peripheral wall (72). Purification device according to claim 10, characterized in that the purification device (1) comprises: a peripheral web (88) of fibrous material interposed between firstly the first and second substrates (22, 26) and secondly the single peripheral wall (72), the peripheral layer (88), considered perpendicular to the first direction (D1), completely surrounding the first and second substrates (22, 26); - an intermediate web (90) of fibrous material interposed between the first and second substrates (22, 26). Purification device according to one of the preceding claims, characterized in that : the first purification unit (20) comprises a first outer casing (28) delimiting a first exhaust gas inlet (30) and a first exhaust gas outlet (32); the second purification unit (24) comprises a second outer envelope (34) delimiting a second exhaust gas inlet (36) and a second exhaust gas outlet (38); the exhaust gas purifying device (1) further comprising a volume (40) fluidically connecting the first outlet (32) to the second inlet (36) or the second outlet (38) to the first inlet (30) the volume (40) being delimited by a cover (92) attached directly to the first and second outer shells (28, 34). Vehicle exhaust line comprising a purification device according to claim 1.

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