DE29615840U1 - Exhaust manifold with flange - Google Patents

Description

Description:

The invention relates to exhaust manifolds with at least one flange for connecting the pipe manifold to an engine block and/or an exhaust system according to the preamble of claim 1.

Exhaust manifolds, which collect the hot exhaust gases coming out of the exhaust valves and lead them to the exhaust system, consisting of exhaust pipes, catalytic converter and silencer, were originally manufactured as cast parts. Compare, for example, US-A 2 847 819. The flange used to screw the exhaust manifold onto the engine block poses the greatest problems, as the flange must be screwed on gas-tight. In addition, modern engine construction prescribes certain shapes and thicknesses of the flanges, which led to high financial expenditure during casting. In addition, cast parts always have to be reworked, which is expensive, especially because of the complicated shapes.

For this reason, pipe manifolds are increasingly being used. These consist of manifold pipes of suitable length and shape or pressed half shells that are welded to a flange, which in turn then creates the connection to the engine block. A flange can also be provided at the other end of the manifold pipes to connect to the further exhaust system.

It goes without saying that special requirements are placed on the flanges, especially the flange to be connected to the engine block. For this reason, it has always been suggested that this flange should be given a high level of inherent rigidity. In this regard, compare

DE-OS 15 76 357, which provides a separate small flange for each cylinder outlet.

DE 31 29 351 C2 discloses a flange for pipe manifolds on combustion engines, which is divided in the direction of the thickness of the flange. The incoming pipe of the manifold is only welded to one part of the flange. This part of the flange is then welded to the other part of the flange. This is intended to better absorb the forces arising as a result of the thermal stress. Nevertheless, a separate, small-area flange is also provided for each cylinder outlet.

Finally, EP 0 178 430 Bl discloses an exhaust manifold with a flange for fastening the exhaust manifold to the engine block. The flange is made up of four relatively thin sheet metal plates, which are at least partially made of stainless steel. These are individually punched, stacked with the help of fitting holes and dowel pins to ensure a precise fit, and finally brazed. The top sheet metal plate is provided with a hole into which a manifold pipe can be welded. This flange is already suitable for two cylinder outlets.

All flanges disclosed in the literature mentioned above have in common that the required inherent stability is achieved by a high flange thickness, regardless of whether the flange is made of one piece, two pieces or four pieces. All of these flanges have a high material consumption, are heavy and expensive. They are also obviously not able to cover all of the cylinder outlets of an engine in one piece, for example four in the most common four-cylinder in-line engines.

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The present invention is therefore based on the object of specifying an exhaust manifold whose flange can be manufactured considerably more simply and lighter and thus also more inexpensively, whereby the required inherent rigidity and the required gas tightness are ensured for every size.

This object is achieved by an exhaust manifold having the features of claim 1.

The flange of the exhaust manifold according to the invention consists of a thin-walled sheet metal which, through suitable shaping in the deep-drawing process, has an edge angled at around 90°, at least partially all the way around, as well as through-holes and, if necessary, additional reinforcing beads. The gas-tightness is achieved by additional features running around the pipe openings and slightly protruding above the surface of the plate. These are produced during the deep-drawing of the sheet metal plate or after the deep-drawing of the sheet metal plate in a further operation, so that all sealing surfaces are absolutely flat. Machining post-processing can therefore be completely eliminated.

According to an advantageous development of the invention, corresponding protruding surfaces are also formed around the fastening openings. This means that all the ring surfaces surrounding the passages lie in the same plane. This ensures that the flange cannot be deformed when the fastening screws are tightened.

Tests have shown that sufficient dimensional stability of the flange is achieved if the height of the edge and/or the openings is at least equal to the thickness of the sheet.

Advantageously and depending on the application, the flange is made of non-refined steel.

The invention will be explained in more detail in the form of exemplary embodiments with reference to the drawing.

Fig. 1 shows a schematic representation of an exhaust manifold, flanged to a section of an exhaust system,

Fig. 2 is a plan view of the rear side of a flange for a four-cylinder in-line engine,

Fig. 3 is a section through the flange of Fig. 2 along the line IH-III,

Fig. 4 a plan view of the sealing side of a two-pipe flange and

Fig. 5 is a section through the flange of Fig. 4 along the line V-V.

Fig. 1 shows a purely schematic top view of an exhaust manifold. First of all, you can see a flange 10 that connects to an engine block (not shown) of a four-cylinder in-line engine. Four manifold pipes or shells 11 are welded to the flange 10. Two of the manifold pipes are joined together to form manifold pipes 12. These are in turn welded to a two-pipe flange 20.

The pipes 21 that carry the exhaust gas are in turn welded to a two-pipe flange 20. The two two-pipe flanges 20 are screwed together.

Fig. 2 as a top view and Fig. 3 as a section along the line III-III show the four-hole flange 10 in an enlarged view. It can be seen that the openings 13, in which the manifold pipes or shells II are welded, are designed as through holes. In addition, an approximately vertically angled, partially circumferential or completely circumferential edge 17 is also formed using the deep-drawing process. These two measures already guarantee the required rigidity of the flange 10. The flange 10 is preferably made of non-alloyed steel, e.g. St 52.

On the flange 10 you can also see a whole series of fastening openings 15, which in this embodiment are designed as simple holes and not as through holes. However, these can also be provided with through holes.

Ring-shaped surfaces 14, 16 can be seen running around the openings 13 and the fastening openings 15. Their surface protrudes slightly above the surface of the sheet metal plate. The surfaces of the ring surfaces 14, 16 are absolutely flat and lie in the same plane thanks to a corresponding non-cutting machining process. This ensures that the connection between the engine block and the flange is gas-tight and reliably prevents deformation of the flange when tightening the connecting screws (not shown).

Fig. 4 as a top view and Fig. 5 as a section along the line V-V show the two-pipe flange 20 in an enlarged view. One can again see the completely or partially circumferential edge 26 angled at about 90° and the passages 22 of the openings. Here are also the

Fastening openings 24 designed as passages.

An exhaust pipe 12, 21 is inserted into one of the openings 22. The connection is made using circumferential weld seams 27, 28, which can be attached either externally (item 27) or internally (item 28).

It has been found that even when using the widely used MAG welding process, only minimal, easily tolerable thermal distortion occurs. This can be further minimized when using the laser welding process.

Claims (5)

Protection claims: 1. Exhaust manifold with at least one flange (10, 20) for connecting the exhaust manifold to an engine block and/or an exhaust system, wherein openings (13, 22) into which the manifold pipes or shells (11) are welded and fastening openings (15, 24) for screws or plug bolts are provided in the flange (10, 20), characterized in that the flange (10, 20) is deep-drawn from a sheet metal plate, that a completely or partially circumferential edge (17, 26) angled at approximately 90° is formed, that the openings (13, 22) and at least some of the fastening openings (15, 24) are formed as passages and that sealing surfaces (14, 23) are formed around the openings (13, 22) and protrude above the surface of the sheet metal plate. 2. Exhaust manifold according to claim 1, characterized in that corresponding projecting surfaces (16, 25) are also formed around the fastening openings (15, 24). 3. Exhaust manifold according to claim 1 or 2, characterized in that the height of the edge (17, 26) and/or the passages (13, 15; 22, 24) corresponds at least to one time the sheet thickness. 4. Exhaust manifold according to claim 1, 2 or 3, characterized in that at least one flange (10) consists of non-alloyed steel. 5. Exhaust manifold according to one of claims 1 to 4, characterized in that the flange (10) has more than two openings (13) for manifold pipes or shells (11).