Manifold For A Multicylinder Internal Combustion Engine

Abstract

A manifold for a multicylinder internal combustion engine which includes a plurality of outlets (1) comprises upper, lower and central shells (15, 5, 51) that are connected with one another and define inlet channels and outlet spaces (63, 65). A baffle plate (35) is attached to different shells (5, 15) by means of a fixed/movable bearing and can expand thermally without transferring thermal stresses to the shells (5, 15).

Description

The present invention relates to a manifold composed of a plurality of shells, for a multicylinder internal combustion engine.

In particular, the invention relates to a so-called three-shell manifold, in which a lower, an upper and a central shell are connected with one another on the edges, so that a plurality of inlet channels and a plurality of associated outlet spaces are provided. Each outlet on the engine block side opens into a separate, associated inlet channel of the manifold, which in turn continues into an outlet space. Generally, several inlet channels continue into a shared outlet space, in which the hot exhaust gases spread, expand and are cooled to some degree. The manifolds are exposed to extreme thermal stresses. These stresses are extreme in particular in the areas of the connecting weld seams between the shells and the wall sections which are impinged by the exhaust gas stream directly from the engine. Also, especially in a cold start, different sections of the manifold expand with varying degrees of rapidity and intensity, so that high tensions develop here in the areas of the weld seams.

The invention is intended to reduce these stresses on the weld seams and the walls and to largely uncouple the walls of the outlet spaces from one another in terms of forces.

This is achieved by a manifold for a multicylinder internal combustion engine which includes a plurality of outlets, comprising a plurality of shells connected with one another on the edges to provide inlet channels and at least one outlet space into which the inlet channels or at least some of the inlet channels open, and a baffle plate that is provided for the exhaust gas flowing in via at least one inlet channel and is associated with an outlet space, the baffle plate being firmly connected on the edge at one end with one of the shells and being displaceably connected with another one of the shells at an end remote therefrom.

The exhaust gas from the outlets of the engine which enters the manifold first impinges on the baffle plate which, as a consequence, is subjected to the highest thermal stresses. This baffle plate, however, does not connect shells directly with each other, but is displaceably attached to one shell, so that it can expand thermally without this resulting in tensions between the shells. Furthermore, the baffle plate distributes the flow in the outlet space, forming, as it were, a section of the wall thereof, and in this way provides for a more uniform and faster temperature distribution of the hot exhaust gas in the outlet space, so that the other wall sections of the outlet space are likewise subjected to more uniform and therefore lower stresses as a whole.

According to the preferred embodiment, the manifold according to the invention is provided with lower and upper shells connected with one another on the edges to provide outer inlet channels and an outlet space into which the outer inlet channels open, and a central shell connected on the edge with at least one of the lower and upper shells to provide at least one middle inlet channel located between the outer inlet channels and a second outlet space into which the middle inlet channel opens. The baffle plate is provided for the exhaust gas flowing in via the middle inlet channel and is associated with the second outlet space, and at one end it is firmly connected on the edge with one shell and at an opposite end it is displaceably connected with another shell.

According to the preferred embodiment, one end of the baffle plate is welded to a shell in order to arrange for a secure, rigid connection.

At the displaceable end, the attachment of the baffle plate is constituted e.g. by a U-shaped open end into which an edge projects, so that it is guided between the legs of the U-shaped end.

In this connection it is possible for the edge to be provided on the baffle plate or else, in preference, on a shell, so that in this preferred embodiment the U-shaped end is situated on the baffle plate.

One end of the baffle plate, for example, is attached to the lower shell and prevents the lower shell from being directly impinged by the flow.

The upper shell may have a cut-out in the region of the baffle plate and therefore have the shape of a U, so that the baffle plate is seated inside the “U” and possibly even fills it out completely.

Further features and advantages of the invention will be apparent from the description below and from the accompanying drawings, to which reference is made and in which:

FIG. 1 shows a diagrammatic sectional view of the manifold according to the invention in a plane parallel to the engine flange;

FIG. 2 shows a perspective top view onto the manifold according to the invention, with the central shell being illustrated partly cut open in the middle in order to expose a view onto the baffle plate; and

FIGS. 3 and 4 show perspective sectional views in the regions of the planes III-III and IV-IV, but slightly turned in order to expose the view onto the cut-open manifold in the area of the second outlet space.

FIG. 1 illustrates a manifold for a four-cylinder internal combustion engine, the internal combustion engine having four outlets 1 which, in relation to the cutting plane of FIG. 1, would be located above the plane of projection and are indicated by broken lines only for the purpose of an enhanced understanding.

The manifold, which is bolted to the engine block, has a flat, plate-like flange 3 (see FIG. 2) and three shells made of sheet metal and connected with each other, which define inlet channels for each outlet 1 and outlet spaces that combine a plurality of inlet channels.

A lower shell 5 made of sheet metal has a trough-shaped section 7 and four extensions which protrude to the flange 3 and have been reshaped to form a lower tube part 9, 11 and 13. Because of the sections performed, the fourth lower tube part is not shown in the figures. Each lower tube part 9 through 13 has the shape of a half-shell. The lower tube parts 9 through 13 project through corresponding openings in the flange 3 and are attached thereto.

Placed on the lower shell 5 is an upper shell 15 having an outer edge 17 which is welded and/or crimped to the outer edge 19 of the lower shell 5. The upper shell 15 has only two extensions pointing towards the flange 3, which have been reshaped into upper tube parts 21, 23 in the shape of half-shells (see FIG. 2). The upper tube parts 21, 23 are in contact with the two outer lower tube parts (lower tube part 9 and the lower tube part that is not shown) and are connected with the latter on the edges, so that two outer inlet channels 25, 27 are formed, which are associated with the outer outlets 1.

In the region of the middle outlets 1, the upper shell 15 has a depression (see FIG. 1) which extends remote from the flange 3 to closer to the flange 3 increasingly downward towards the lower shell 5. This depression is defined by a wall 29 facing the rear side of the flange and by side walls 31 which continue into the wall 29. The wall 29 has a cut-out 33, so that the upper shell 15, as viewed from the top, is formed in the shape of a U.

The width of the cut-out 33, as related to FIG. 1, is adapted to the width of the baffle plate 35, which has a lower end 37 welded to the lower shell 5, the weld seam being denoted by 39. The width of the baffle plate 35 is selected such that in the view according to FIG. 1, it covers both projections of the middle outlets 1. As shown in FIGS. 3 and 4, the baffle plate 35 extends from the lower shell 5 obliquely upward and away from the flange 3 towards the wall 29, which likewise extends obliquely upward and away from the flange 3.

The wall 29 and the baffle plate 35 partly run parallel to each other in the vicinity of the lateral edges of the baffle plate 35.

A U-shaped metal plate 43 which extends across the entire width of the baffle plate 35 is welded onto the rear side of the baffle plate 35, in the area of the upper end 41 thereof (see FIGS. 3 and 4). The metal plate 43 also extends downward along the lateral edges of the baffle plate 35. The baffle plate 35 and the metal plate 43 are somewhat bent away from each other behind the welding point, so that they constitute a receiving groove which is U-shaped in cross-section and open to the outside and which extends along the lateral edges and the upper end 41. The edge 45 of the cut-out 33 is inserted so as to be displaced within this receiving groove, so that a displaceable bearing is produced between the baffle plate 35 and the upper shell 15.

A central shell 51 is located above the area of the indentation of the upper shell 15 and the baffle plate 35. The central shell 51 has two extensions pointing towards the flange 3, which form upper tube parts 53, 55 and are connected with the middle lower tube parts 11, 13 of the lower shell 5 to define two middle inlet channels 57, 59.

The displaceable connection between the upper shell 15 and the baffle plate 35 may be, but need not be, limited to the upper edge 41. Rather, as described above, additionally or alternatively the lateral edges of the baffle plate 35 may also be correspondingly connected for displacement with the upper shell 15.

The lower and upper shells 5, 15 constitute a common outlet space 63 which extends beneath the baffle plate 35 and into which the two outer inlet channels 25, 27 open.

The two middle inlet channels 57, 59 open into a common, second outlet space 65 which is defined by the baffle plate 35, the middle portion of the upper shell 15, and the central shell 51.

Both outlet spaces 63, 65 lead to a single exhaust pipe 67 (FIG. 2), which is defined by the lower and central shells 5, 51.

The exhaust pipe 67 is divided in two by a tongue 81 of the upper shell 15 running transversely through the exhaust pipe 67, dividing it into an upper section for the middle inlet channels 57, 59 and a lower section for the outer inlet channels 25, 27.

This division of the flow is advantageous if a turbocharger operating according to the twin scroll concept is connected to the manifold.

As an alternative, the outlet spaces 63, 65 could also be united within the manifold, or else a shared outlet space could be provided.

The exhaust gas flowing into the middle inlet channels 57, 59 strikes directly onto the baffle plate 35 and is distributed by the latter in the second outlet space 65 to finally reach the exhaust pipe 67, from where it flows to the turbocharger and to exhaust gas purification systems.

Claims

1.-8. (canceled)

9. A manifold for a multicylinder internal combustion engine which includes a plurality of outlets, comprising: a plurality of shells connected with one another on the edges to provide inlet channels and at least one outlet space into which the inlet channels open, anda baffle plate that is provided for the exhaust gas flowing in via at least one inlet channel and is associated with an outlet space, the baffle plate being firmly connected on the edge at one end with one of the shells and being displaceably connected with another one of the shells at an end remote therefrom.

10. The manifold according to claim 9, wherein: the plurality of shells includes lower and upper shells connected with one another on the edges to provide outer inlet channels and a first outlet space into which the outer inlet channels open,the plurality of shells further includes a central shell connected on the edge with at least one of the lower and upper shells to provide at least one middle inlet channel located between the outer inlet channels and a second outlet space into which the middle inlet channel opens, andthe baffle plate being provided for the exhaust gas flowing in via the middle inlet channel and being associated with the second outlet space.

11. The manifold according to claim 10, wherein the baffle plate is attached to the lower shell.

12. The manifold according to claim 10, wherein the upper shell has a cut-out in the region of the baffle plate and is U-shaped.

13. The manifold according to claim 9, wherein the displaceably connected end of the baffle plate is located opposite to the firmly connected end.

14. The manifold according to claim 9, wherein one end of the baffle plate is welded to a shell.

15. The manifold according to claim 9, wherein the displaceable end is a U-shaped open end into which an edge projects and is guided therein.

16. The manifold according to claim 15, wherein the baffle plate has the U-shaped end.