FR2851961A1 - Turbo-compressor collector and exhaust collector connecting device for use in vehicle, has ring mounted axially on section of exit end of exhaust collector or on section of input end of turbo compressor collector - Google Patents

Abstract

The device (10) has a ring (48) that is mounted axially on a section of an exit end (38) of an exhaust collector or on a section of an input end (46) of a turbo compressor collector. The ends (38,46) are maintained in axial support against a down stream opening of the ring by a tie rod. The tie rod takes axial support against an upstream opening of the ring. The tie rod is interposed by a plain washer having a support surface.

Description

i

  The present invention relates to a sealing connection device for an internal combustion engine.

  The present invention more particularly relates to a device for sealing connection between the exhaust manifold of an internal combustion engine and the collector of a turbocharger which is rigidly fixed to the engine, the exhaust manifold having an outlet end which 10 is intended to be connected to the inlet end of the turbocharger manifold.

  A connection interface (10) between the turbocharger manifold (12) and the exhaust manifold (14) is generally provided in the form of a flat flange as shown in FIG.

  According to this known embodiment, the ends vis-à-vis the two collectors each comprise an outer collar (16, 18) provided with holes for the passage of fastening means (20) of the screw / nut type. The fastening means 20 hold the two flanges tight against each other, and a seal (22) is interposed axially between the two flanges.

  When the turbocharger is rigidly attached to the engine block, the thermomechanical stresses that apply to the connecting interface between the turbocharger manifold and the exhaust manifold are very important. These important constraints are explained in particular by the differential expansion between the exhaust manifold and the turbocharger manifold, these being made in different materials, therefore different expansion coefficients.

  This phenomenon is amplified on recently designed engines that emit a very high thermal energy in the exhaust gases.

  Since the flanges of the interface flange are made by molding, they generally have massive shapes that are very sensitive to expansion and that contribute to the increase in the thermomechanical stresses that apply to the interface.

  The forces produced by these thermomechanical stresses on the parts of the turbocharger and the exhaust manifold are detrimental to a good mechanical resistance of the parts over time, as well as to the tightness of the connection. However, the tightness of the connection is necessary to maintain the exhaust gas pressure and temperature.

  To solve this problem, it has been proposed to assemble the exhaust manifold with the turbocharger manifold by welding. But the thermomechanical stresses are too great, which can cause a rapid deterioration of the weld.

  Another solution considered is to make the turbocharger collector in one piece with the exhaust manifold. However, this solution requires the realization of cast iron collectors, which leads to an absorption of the calories conveyed by the exhaust gases in the collectors, while it is sought to transmit these calories to the catalytic converter.

  This solution also poses problems of flowability during the realization of foundry collectors.

  The invention therefore aims to remedy these problems by proposing a new sealed connection device making it possible to attenuate the stresses associated with the differential expansion between the materials of the exhaust manifold and the turbocharger manifold.

  For this purpose, the invention proposes a sealed connection device of the type described above, characterized in that it comprises a ring which is slidably mounted axially on the end section of the exhaust manifold, or on the section of pipe. the end of the turbocharger manifold, and in that the end of the turbocharger manifold, respectively the end of the exhaust manifold, is mounted on the ring.

  According to other features of the invention - the end of the turbocharger manifold, respectively the end of the exhaust manifold, is held in axial abutment against a downstream bearing of the ring by at least one tie rod which bears axially against an upstream range of the ring; - The connecting device comprises several tie rods 10 which bear against the upstream bearing surface of the ring with the interposition of a clamping washer having a bearing surface complementary to the upstream range; the upstream and downstream bearing surfaces of the ring and the complementary bearing surfaces which are formed in the clamping washer and in the end of the turbocharger manifold, respectively in the end of the exhaust manifold, have a profile overall. frustoconical or hemispherical, so as to form a sliding pivot type connection between the turbocharger manifold and the exhaust manifold; - The ring forms a dynamic seal for the connection between the two collectors.

  Other features and advantages of the invention will appear on reading the detailed description which follows for the understanding of which reference will be made to the appended drawings in which: FIG. 1 is an axial sectional view which schematically represents a device connection according to the state of the art; FIG. 2 is a block diagram illustrating the arrangement of a connection device in an internal combustion engine of a motor vehicle; - Figure 3 is a perspective view which schematically shows a connecting device made according to the teachings of the invention; FIG. 4 is a view in axial section similar to that of FIG. 1, which schematically represents the connecting device of FIG. 3. In the following description, identical, similar or similar elements will be designated by the same numbers of FIG. reference. In particular, the same references will be used for parts that are similar to those of the connection device according to the state of the art, described with reference to FIG.

  Figure 2 is a block diagram showing the arrangement of the connecting device 10 on an internal combustion engine 24 of a motor vehicle.

  The engine 24 comprises a motor unit 26 on which is fixed a cylinder head 28 and a turbocharger support 30.

  An exhaust manifold 14 is fixed on the cylinder head 28 so as to evacuate the exhaust gas to an exhaust line 32, which is equipped here with a catalyst 34.

  A turbocharger 36, which is attached to the engine block 26 via the carrier 30, is interposed between the exhaust end 38 of the exhaust manifold 14 and the exhaust line 32.

  The turbocharger 36 comprises a turbine casing 40 and a compressor casing 42 which are integral with a bearing housing 44 carried by the support 30.

  The turbine casing 40 comprises a turbocharger manifold 12, which is connected to the exhaust manifold 14 via the sealed connection device 10.

  Typically, the exhaust gases from the exhaust manifold 14 are thus fed into the turbine casing 40 through the turbocharger manifold 12, thereby rotating a turbine wheel (not shown) prior to to be evacuated to the outside by the exhaust line 32.

  According to a conventional operation of the turbocharger 36, the rotation of the turbine wheel makes it possible to compress intake gases in the compressor casing 42 so as to supercharge the motor 26.

  With reference to FIGS. 3 and 4, a sealing connection device 10 made in accordance with the teachings of the invention will now be described.

  For the description of the invention, an axial orientation along the axis A-A of the end portion 38 of the exhaust manifold 14 will be adopted without limitation.

  Elements will be qualified upstream, or downstream, with reference to the direction of flow of the exhaust gases in the manifolds 12, 14, which corresponds here to a movement from right to left, considering Figure 4 .

  FIGS. 3 and 4 show the outlet end 38, or downstream end, of the exhaust manifold 14 and the inlet end 46, or upstream end, of the turbocharger manifold 12.

  According to the teachings of the invention, the connecting device 10 comprises a ring 48 which is slidably mounted axially on the end section 38 of the exhaust manifold 14, and the end 46 of the collector of the turbocharger 12 is mounted on the ring 48.

  According to the embodiment represented here, the ring 48 comprises an upstream bearing surface 50 and a frustoconical downstream bearing surface 52, as well as an internal axial surface 53 which is designed to slide axially, in a sealed manner, on the outer axial surface of the section. end plate 38 of the exhaust manifold 14.

  The ring 48 thus has a profile, in axial section, generally trapezoid-shaped, here isosceles, the largest side of which is in contact with the end section 38.

  The end 46 of the turbocharger manifold 12 here comprises a flange 54 which extends radially outwards, and which is provided with a frustoconical bearing surface 56 complementary to the downstream bearing 52 of the ring 48. The surface tapered support 56 here forms the inner edge of the flange 54.

  The connection device 10 also comprises an annular clamping washer 58 which is provided with a frustoconical bearing surface 60 complementary to the upstream bearing surface 50 of the ring 48. The frustoconical bearing surface 60 here forms the inner edge of the washer 58.

  The frustoconical bearing surface 56 of the flange 54 of the turbocharger manifold 12 is held in axial abutment against the downstream bearing 52 of the ring 48 by the clamping washer 58.

  For this purpose, the connecting device 10 here comprises a series of tie rods 62.

  Each tie 62 passes through an axial hole 64 of the washer 58 and is screwed into a tapped axial hole 66 which is formed in the upstream radial face 68 of the flange 54. Each tie rod 62 comprises a head 70 which bears axially against the face 20 upstream radial 72 of the washer 58.

  According to an alternative embodiment (not shown) of the invention, the frustoconical bearing surfaces 50, 52 can be replaced by generally hemispherical profile bearing surfaces, the complementary bearing surfaces 56, 60 of the collar 54 and 25 of the washer 58. being then of hemispherical profile.

  The frustoconical, or hemispherical, shape of the bearings 50, 52 of the ring makes it possible to form a sliding pivot type connection between the turbocharger manifold and the exhaust manifold.

  This allows the two collectors 12, 14 to move slightly relative to each other, either by an axial sliding of the ring 48 on the end section 38 of the exhaust manifold 14, or by a globally sliding transverse bearing surfaces 56, 60 of the flange 54 and the washer 58 on the frustoconical bearing surfaces 50, 52, or hemispherical, of the ring 48.

  Advantageously, the ring 48 forms a dynamic seal for the connection between the two manifolds 12, 5 14. Thus, despite the relative movements of the exhaust manifold 14 relative to the turbocharger manifold 12, due to the vibrations to which are subjected parts or due to the expansion of the parts, the connecting device 10 according to the invention ensures a perfect seal 10 between the two collectors 12, 14.

  The ring 48 is for example made of a metal alloy which can be deformed slightly when it is constrained, so as to ensure a good seal between the exhaust manifold 14 and the turbocharger manifold 12, under the tension of the tie rods. .

  According to an alternative embodiment (not shown), it is possible to provide an additional piece forming a seal between the exhaust manifold 14 and the turbocharger manifold 12. In this case, the contact zones between the ring 48 and the exhaust manifold 14, as well as the contact areas between the ring 48 and the turbocharger manifold 12 no longer need to be sealed.

  According to another embodiment (not shown) of the invention, the flange 54 can be held in axial bearing 25 against the ring 48, without the interposition of the washer 58, the tie rods then bearing directly against upstream spans of adapted to the heads 70 of the tie rods 62.

  Of course, it is understood that, by a simple mechanical inversion, it is possible to mount the ring 48 on the collector 30 of turbocharger 12 and mount the end 38 of the exhaust manifold 14 on the ring 48 which then slides on the turbocharger manifold 12.

  The connecting device 10 according to the invention allows an expansion of the turbocharger manifold 12 and the exhaust manifold 14 without this expansion causes deterioration of the engine parts 24 or the sealing of the connection.

  An advantage of the connecting device 10 according to the invention is that it combines an assembly function and a sealing function.

  Another advantage of the connecting device 10 according to the invention is the favorable thermal balance due to the fact that the turbocharger collector 12 can be made of thin sheet metal.

  The connecting device 10 has been shown here with parts of generally cylindrical outer shapes. Of course, according to alternative embodiments (not shown) of the invention, the various parts of the connecting device 10 15 such as the flange 54, the ring 48, and the washer 58, could have different external shapes, for example triangular or rectangular shapes, in the same way that flat flanges can have different shapes.

Claims (5)

  1. Sealed connection device (10) between the exhaust manifold (14) of an internal combustion engine (24) and the manifold (12) of a turbocharger (36) which is rigidly fixed to the engine ( 24), the exhaust manifold (14) having an outlet end (38) which is adapted to be connected to the inlet end (46) of the turbocharger manifold (12), characterized in that it comprises a ring (48) which is slidably mounted axially on the end section (38) of the exhaust manifold (14), or on the end section (46) of the turbocharger manifold (12), and in that that the end (46) of the turbocharger manifold (12), respectively the end (38) of the exhaust manifold (14), is mounted on the ring (48).   2. Device (10) according to the preceding claim, characterized in that the end (46) of the turbocharger collector (12), respectively the end (38) of the exhaust manifold (14), is maintained in axial bearing against a downstream bearing (52) of the ring (48) by at least one tie rod (62) bearing axially against an upstream bearing surface (50) of the ring (48).   3. Device (10) according to the preceding claim, characterized in that it comprises several tie rods (62) which bear against the upstream bearing (50) of the ring (48) with the interposition of a clamping washer (58). ) having a bearing surface (60) complementary to the upstream bearing surface (50).   4. Device (10) according to the preceding claim, characterized in that the upstream (50) and downstream (52) surfaces of the ring (48) and the complementary bearing surfaces (56, 60) which are formed in the clamping washer (58) and in the end (46) of the turbocharger manifold (12), respectively in the end (38) of the exhaust manifold (14), have a generally frustoconical or hemispherical profile, so as to forming a sliding pivot type connection between the turbocharger manifold (12) and the exhaust manifold (14).   5. Device (10) according to any one of the preceding claims, characterized in that the ring (48) 5 forms a dynamic seal for the connection between the two collectors (12, 14).