FR2878894A1 - EXHAUST VOLUME - Google Patents

Abstract

The exhaust volume (10) comprises a main enclosure (12) having on either side a passage (20A, 20B) for the circulation of the exhaust gases. It comprises at least one shell (30) in the form of a bowl having an opening delimited by the peripheral edge (36) of the shell, the or each shell (30) being sealingly connected to the outer surface of the main enclosure (12) along the peripheral edge (36). The main enclosure (12) comprises, facing the shell (30), a plurality of perforations (40) for placing the interior of the enclosure (12) and the interior of the shell (30) in communication. ).

Description

The present invention relates to an exhaust volume of the type comprising

  a main enclosure having on both sides an exhaust gas flow passage.

  Motor vehicles propelled by a heat engine are equipped with an exhaust line to limit noise and possibly to clean up the exhaust gases before their release into the atmosphere.

  The exhaust lines are provided, along their length, exhaust volumes for either forming exhaust silencers for damping the sound energy, or to contain pollution control organs such as a purification member catalytic or particulate filter.

  On low-priced vehicles, the exhaust volumes and, more specifically, the exhaust silencers are formed by a shell consisting of a rolled sheet whose longitudinal edges are connected to each other in particular by crimping. End walls, commonly referred to as "cups" are attached to each end of the shell by crimping or welding. Passages for the circulation of gases are predicted through the cups.

  Such an exhaust volume has a reduced price because of its low complexity manufacturing mode. However, the external shape of the exhaust volume can only be regular, that is to say consisting of a form of revolution such as a cylinder or a cone.

  For more high-end vehicles, it is known to provide exhaust volumes whose shape is optimized to provide a maximum volume exhaust, while having externally a small footprint. For this purpose, the exhaust volume has externally a complex shape complementary to that of the housing formed in the vehicle body to receive the exhaust volume.

  Thus, these exhaust volumes generally have a substantially parallelepipedal shape, each of the faces having projections and recesses to fit as closely as possible the complementary shape of the vehicle structure.

  Such exhaust volumes are manufactured from two half-shafts connected along their peripheral edge by an intermediate weld. Each half-shell is formed by stamping a metal sheet.

  The two half-shells provide the mechanical strength of the exhaust volume, so that the sheets used to form these two half-cups must be relatively thick and rigid. Thus, the stamping process of this sheet is relatively difficult to implement, which increases the total cost for such exhaust mufflers.

  The object of the invention is to propose an exhaust volume that makes it possible to obtain complex shapes externally in order to optimize the space occupied by the exhaust volume given the external constraints for its implementation.

  For this purpose, the invention relates to an exhaust volume of the aforementioned type, characterized in that it comprises at least one bowl-shaped shell having an opening defined by the peripheral edge of the shell, the or each shell being sealingly bonded to the outer surface of the main enclosure along the peripheral edge, and in that the main enclosure has, facing the shell, a plurality of perforations of communication of the inside the enclosure and inside the hull.

  According to particular embodiments, the exhaust volume has one or more of the following characteristics: the number of perforations is greater than 30; the diameter of the perforations is between 3.5 mm and 5 mm; - The shell is delimited by a sheet whose thickness is between 0.1 mm and 0.2 mm; - The main enclosure is formed of a sheet of thickness between 0.3 mm and 1.4 mm; the shell is delimited by an embossed sheet; - The shell is formed by stamping the embossed sheet; the space delimited between the shell and the outer surface of the enclosure is filled with fibers; it has fastening lugs secured only on the holster and not on the hull; the main enclosure is delimited by a rolled shell, the longitudinal edges of the shell being connected to one another in a longitudinal connection to form a tube, the enclosure being closed at each end of the shell by transverse walls reported and each traversed by an exhaust gas circulation passage; and the main enclosure is delimited by two half-shells stamped and contiguous.

  The invention will be better understood on reading the description which follows, given solely by way of example, and with reference to the drawings, in which: FIG. 1 is a perspective view of a first embodiment of embodiment of an exhaust volume according to the invention Figure 2 is a sectional view of the exhaust volume of Figure 1; Figure 3 is a sectional view of a variant of the exhaust volume according to the invention; and FIG. 4 is a perspective view of yet another embodiment of an exhaust volume according to the invention.

  FIG. 1 shows an exhaust volume 10 according to the invention, and more particularly, in the example under consideration, an exhaust muffler capable of being integrated in an exhaust line and intended to dampen the noise pollution due to at the pulsed regime of the exhaust gas flowing in the line.

  The exhaust volume comprises a main enclosure 12 defined by a shell 14 rolled and crimped. In the example considered, the enclosure 12 is generally cylindrical with a circular section. The shell consists of a generally rectangular sheet blank rolled so as to cause the opposite longitudinal edges to meet. These longitudinal edges are connected to one another, in particular by crimping, along a connecting line 16 extending along a generatrix of the enclosure.

  Alternatively, the closed shell has a frustoconical shape.

  At each end of the shell 14, the enclosure is closed by an end wall 18A, 18B commonly referred to as "cup". These walls are formed of a metal disc crimped around the periphery of the ferrule. An exhaust passage 19A, 19B is formed in each wall 18A, 18B and forms an inlet and an outlet for the exhaust gas. These passages 19A, 19B are each extended by an inlet pipe 20A and an outlet pipe 20B.

  The sheet used to delimit the enclosure and more specifically to form the ferrule 14 and the end walls 18A, 18B is a sheet of steel commonly used for exhaust lines such as steel-based ferritic type 1.45.10 or austenitic steel type 1. 43.01. The thickness of the sheet is between 0.3 and 1.4 mm and preferably between 0.4 and 1.0 mm, so as to ensure sufficient rigidity to the main enclosure 12 so that it is self-supporting that is, it is able to maintain its shape without any other support element.

  According to the invention, a complementary shell 30 is attached to the outer surface of the main enclosure 12 to form a complementary space 32. The shell 30 is formed of an embossed sheet which is shaped by folding or pressing in press.

  This shell delimits a bowl shape having an opening delimited by a peripheral edge 36.

  The shell 30 is sealingly connected to the outer surface of the enclosure 12 by a connection formed along the entire peripheral edge 36. In the example illustrated, the shell 30 is connected along two connecting lines 36A, 36B. extending longitudinally along the generatrices of the enclosure 12 and by two links 36C, 36D extending along semicircles in planes generally transverse to the enclosure 12.

  Preferably, the connection made along the peripheral edge 36 of the shell on the enclosure is carried out by knuckle welding or else by weaving, possibly by beating with the end walls 18A, 18B.

  In order to ensure communication between the interior of the main enclosure 12 and the space defined by the shell 30, a plurality of perforations 40 is formed through the shell 14 only to the right of the shell 30. These perforations are regularly distributed along the surface of the shell 14 covered by the shell 30. They each have a diameter of between 3.5 mm and 5 mm. The number of perforations is preferably greater than 30.

  Advantageously, and in order to reduce noise pollution, the space 32 delimited by the shell 30 is filled with glass fibers or ceramic fibers 42.

  The material used to form the shell 30 is advantageously constituted by an embossed sheet of reduced thickness and in particular between 0.1 mm and 0.2 mm.

  An embossed sheet consists of a sheet blank having a regular matrix of reliefs of reduced size formed by the sheet. These reliefs consist for example of nested hexagons, octagons, stars or any other complementary geometric shapes. Each element of the embossing pattern has an area of between 1 mm 2 and 50 mm 2.

  The forming of the thin embossed sheet is performed in a complex shape with cavities 52 or recesses 54 so that the shell 30 has a shape substantially complementary to the space available in the vehicle to receive the silencer.

  In addition, the exhaust volume includes tabs 56 for attachment to the vehicle structure. These tabs are secured, in particular by welding, only to the enclosure 12 and not to the shell 30.

  In this arrangement, the shell 30, even consisting of a small thickness, is held in shape by being connected to the enclosure 12 which is rigid.

  It is understood that such a silencer is of a reduced manufacturing cost since the bearing structure is formed of a rolled shell and crimped at the ends of which end walls are reported, structure whose manufacturing process is well controlled and cheap. Only a shell 30 is attached to the shell 14, this shell can be shaped even in a complex shape simply and inexpensively because of the great machinability of the embossed sheet used to form the shell.

  The presence of the shell delimits a space in communication with the interior of the enclosure 12 allows to provide a large volume exhaust silencer, but however a reduced manufacturing cost.

  Alternatively, such a chamber is used to receive a pollution control member such as a particle filter or a catalytic purification member.

  Insofar as its thickness is sufficient, the fiber layer acts as thermal insulation.

  In the variant embodiment illustrated in FIG. 3, the enclosure is formed by a shell extending over 360. In particular, the shell 14 is rolled over a turn and a half, so that the enclosure 12 has on one half a double thickness formed by the superposition of two beaches of the shell 14. As before, the edges of the shell are welded longitudinally not with each other but according to the surface of the running part of the ferrule following welds 60.

  Advantageously, the perforations 40 are formed in the median range of the ferrule delimiting the enclosure 12 with a single thickness. However, no perforation is formed through the chamber in the region where it is delimited by two thicknesses of the shell 14. The shell 30 is attached to the right of the single thickness region of the chamber 12 .

  Such a structure makes it possible to obtain a good mechanical strength and acceptable acoustic performances of the exhaust volume, because of the double thickness of the bottom of the enclosure, while making it possible to have an exhaust volume of relatively reduced, the upper part of the enclosure consisting only of a single relatively small thickness.

  Alternatively and whatever the embodiment, the perforations 40 are not distributed over most of! the surface of the enclosure facing the shell 30 but only in particular areas of the enclosure.

  Advantageously, these perforations are formed only on the sides of the enclosure 12, that is to say away from the region of the enclosure disposed immediately below the vehicle structure, thus avoiding too close proximity with the vehicle structure, which could lead to excessive heat transfer.

  According to yet another variant, in the case where the chamber 12 is subdivided into several chambers by internal walls, the perforations are selectively localized only to the right of certain chambers.

  In a variant, the shell 30 extends over only a portion of the surface of the enclosure 12, that is to say that it does not completely cover the wall of the enclosure 12 between the two walls of the enclosure. 'end. The links 36C and / or 36D are then made by welding on the current part of the lateral wall of the enclosure.

  According to yet another variant, the shell 30 extends beyond the end walls, so that 36C and / or 36D links are formed on the end walls 18A, 18B associated.

  According to another variant, the end walls 18A, 18B consist of convergent and divergent tubular profiles obtained by flow spinning.

  In the embodiment of FIG. 4, the enclosure 12 is formed not by a rolled sheet blank and welded longitudinally but by two half-shells 114A, 114B each formed by stamping and connected to one another by a peripheral longitudinal weld 116 made along a rim formed on each half-shell. The inlet 20A and outlet 20B ends are formed by openings formed between the two half-shells.

  Each of the two half-shells 114A, 114B is formed by stamping a sheet of sufficient thickness to ensure satisfactory rigidity of the enclosure.

  A hull noted 130 formed by stamping into an embossed sheet, similar to the shell 30 of the preceding embodiments, is attached to one of the two half-shells. Lights 140 are formed through the wall of the half-shell supporting the shell 130 to the right of the latter.

  In this embodiment, the same enclosure formed of two half-shafts made with simple shapes can be used to form several different series of exhaust volumes, which are distinguished from each other only by the shape of the hull 130 reported.

  This reported shell 130 being made of a material easy to shape, the manufacturing cost of different series of exhaust volumes is reduced.

Claims (11)

  1.- exhaust volume (10) comprising a main enclosure (12) having on both sides a passage (20A, 20B) for the circulation of the exhaust gas, characterized in that it comprises at least one hull; Cup-shaped cup (30) having an opening defined by the peripheral edge (36) of the shell, the or each shell (30) being sealingly bonded to the outer surface of the main enclosure (12) along the peripheral edge (36), and in that the main enclosure (12) has, opposite the shell (30), a plurality of perforations (40) for communicating the inside of the enclosure (12). and from the inside of the shell (30).   2.- exhaust volume according to claim 1, characterized in that the number of perforations (40) is greater than 30.   3.- exhaust volume according to any one of the preceding claims, characterized in that the diameter of the perforations (40) is between 3.5 mm and 5 mm.   4.- exhaust volume according to any one of the preceding claims, characterized in that the shell (30) is delimited by a sheet whose thickness is between 0.1 mm and 0.2 mm.   5.- exhaust volume according to any one of the preceding claims, characterized in that the main enclosure (12) is formed of a sheet of thickness between 0.3 mm and 1.4 mm.   6.- exhaust volume according to any one of the preceding claims, characterized in that the shell (30) is delimited by an embossed sheet.   7.- exhaust volume according to claim 6, characterized in that the shell (30) is formed by stamping the embossed sheet.   8.- exhaust volume according to any one of the preceding claims, characterized in that the space (32) defined between the shell (30) and the outer surface of the enclosure (12) is filled with fibers (42). ).   9.- exhaust volume according to any one of the preceding claims, characterized in that it comprises tabs (56) hooking secured only on the enclosure (12) and not on the shell (30).   10.- exhaust volume according to any one of the preceding claims, characterized in that the main enclosure (12) is delimited by a rolled shell (14), the longitudinal edges of the ferrule being connected to each other. another according to a longitudinal connection (16) to form a tube, the enclosure being closed at each end of the shell (14) by transverse walls (18A, 18B) reported, each having a passage (20A , 20B) of exhaust gas circulation.   11.- exhaust volume according to any one of claims 1 to 9, characterized in that the main enclosure (12) is defined by two half-shells (114A, 114B) stamped and contiguous.