EP0849445B1 - Exhaust manifold and process for its manufacture - Google Patents

Description

The present invention relates to a trough-shaped Exhaust collector for an internal combustion engine with a Exhaust manifold, an engine-side mounting flange, which encloses several cylinder outlets, and an outlet connection comprising an outlet flange. It also relates to a method of manufacture of such an exhaust manifold.

The exhaust gas of several cylinders is generally known an exhaust manifold summarizing an internal combustion engine with several inlet pipes, one pipe junction and an outlet pipe, the inlet pipes each flanged to an outlet of an internal combustion engine are. Such exhaust manifolds are either heavy Castings designed for operation at high temperatures, as they usually occur with hot exhaust gases, are suitable. In addition to the expensive manufacture of the each casting is an elaborate cutting Rework required to fit the mating surfaces to manufacture individual inlet pipe flanges. Between The cylinder head and exhaust manifold flange is an additional one Gasket required to blow off the exhaust gases prevent. The manufacture of such castings is complex and especially with small quantities expensive. Assembly is also time and cost intensive.

The production of several is also known Input pipes, a pipe junction and one Exhaust manifolds having an outlet pipe by welding several single pipes. A corresponding one Manufacturing process is for example in the EP 0321869 A1. Furthermore, from the German patent DE 851421 the coverage several exhaust openings of an internal combustion engine known through a perforated tube. The exhaust manifold in a continuous one attached to the cylinder head Deepening without additional seals flanged and at its open end with a Exhaust pipe connected. Furthermore is from the German Utility model DE 29513513.1 an exhaust manifold known, which is formed from a deformed piece of pipe, which at one end by bruising and welding is closed. In the side wall of the exhaust manifold jump out domes, each one ring-shaped have a closed sealing projection.

The European patent application EP 0718480 A1 discloses a generic trough-shaped exhaust gas collector, its motor-side mounting flange encloses several cylinder outlets and theirs Exhaust gases collected in a common pan to which one common outlet connector connected to an outlet flange is. With such a device the heat losses at low operating loads considerably decreased, causing a rapid increase in Temperature of a downstream catalyst and thus an improved efficiency of the same causes. There are two in the aforementioned publication possible designs of the trough-shaped exhaust gas collector described. The first design is around a casting, which have similar weight and Has processing disadvantages, as in the beginning described prior art is the case. In the second design is one by deep drawing from sheet metal Exhaust manifold produced with an engine side welded thick-walled flange. This is where it comes from inevitably lead to welding delay, which is an elaborate Post-processing and the use of an additional one Seal requires.

US 4537027 A discloses an exhaust manifold, comprising an outer tub-like shell, an inner flat sheet metal part and a flange part, the three Individual parts are welded together. The inner flat sheet metal part and the flange part have openings through which the exhaust gas leaving the cylinder head in the from the outer tub-like shell and the inner flat sheet metal part bounded space enters. With the outer shell is an outlet connector with a Outlet flange firmly connected.

The object of the present invention is a trough-shaped exhaust manifold of the type mentioned to create the inexpensive to manufacture and at the same time easy to use during assembly is.

This object is achieved by an exhaust manifold and a method for its production with the Features of claims 1, 12 and 14 solved.

There are the exhaust manifold and the engine side Mounting flange from an integral Sheet metal part, with the motor-side mounting flange integrally formed with the exhaust manifold and on the edge of which is produced by shaping the sheet; for the sealing contact of the motor-side mounting flange of the mounted exhaust manifold on the The relevant cylinder head is on the engine side Mounting flange formed on a sealing edge. In which Sheet is a heat-resistant, deep-drawable Stainless steel sheet that is for use in hot Exhaust gas temperatures is suitable. By using it a deformed sheet metal component can be used in particular low quantities significantly cost compared to a Cast construction can be saved. In addition, the Exhaust collector wall thicknesses compared to one Cast part, can be reduced, resulting in a weight saving leads and - due to the lower heat capacity - for a faster start of a downstream Catalyst contributes. By the Fixing flange by reshaping the edge of the Exhaust gas collecting tray manufactured in one piece with this is formed, it is achieved that no welding delay occurs as in the prior art of Case is, which means costly machining post-processing is avoided. Furthermore, the low weight of the exhaust manifold and the low Easy assembly ensures the number of components. By forming a sealing edge in the motor-side mounting flange is also achieved that an additional seal is dispensed with can be, which also for easier assembly contributes. The sealing edge can for example be such be designed so that they over the flange level of mounting and sealing flange on the motor side (in hereinafter simply referred to as the mounting flange) protrudes and seals when assembled the flange of the cylinder head. Thereby prevents the sealing edge from blowing off hot exhaust gases. Furthermore, a sealing edge designed in this way acts like a bead and increases the stiffness of the motor side Mounting flange.

By providing a revolving erected On-board area on the motor-side mounting flange its strength is further increased. This can if necessary, an additional one, on the motor side Mounting flange attached loose flange plate (see below).

Another advantageous development of the present Invention provides that a loose flange plate the motor-side mounting flange on the Cylinder head is facing away from the side. Thereby becomes a more even distribution of the contact pressure on the entire mounting flange and thus on the Seal guaranteed. The loose flange plate provides even if the exhaust manifold and motor-side mounting flange from a relative thin sheet is made, a deformation-free, tight contact of the motor-side mounting flange on the cylinder head safely. The possible in this way Reducing the wall thickness of the sheet not only leads to a reduction in manufacturing costs and weight of the exhaust gas collector and to influence the Manufacturability; also the heat storage capacity of the exhaust manifold, which has a positive effect on the Efficiency of a downstream exhaust gas cleaning system affects.

The loose flange plate can be all-round, undivided his. However, for easier assembly, it can be in advantageously also be divided. The Material thickness of such loose flange plates is 5 mm to 10 mm, preferably 8 mm, being simple Structural steels can be used. By using it a loose flange plate is in the installed state Controlled parts sliding under the influence of temperature possible, which avoids tension in the material.

In a further development of the exhaust manifold, the Exhaust gas collecting pan with a wall thickness of 1.8 mm to 2.5 mm, preferably 2 mm. This will make it easy Construction with sufficient strength created. The exhaust gas collecting pan can be made from a conventional one single-layer sheet. A preferred one Further development of the invention is noteworthy characterized in that the exhaust manifold - and accordingly the molded-on mounting flange on the motor side - consists of a multi-layer sheet. This can in particular be constructed as a sandwich sheet, which two layers of sheet metal and in between a layer of fiber fleece or the like.

Furthermore, an advantageous further development of the present invention that the exhaust manifold a substantially constant cross section over the Has longitudinal extension. This causes the wall thickness of the sheet metal part after deep drawing total longitudinal extent of the exhaust gas collecting pan in is essentially the same.

Especially for reasons of fluid mechanics however, it should also be provided that the cross section the exhaust manifold towards the outlet increasingly expanded.

Finally, an advantageous embodiment of the present invention that the outlet port in Direction of the longitudinal extent of the exhaust gas collecting pan one end of the same is arranged. This will Exhaust gas flows within the tub a defined one Given the direction of flow.

Another advantageous embodiment provides that in an internal combustion engine with exhaust gas recirculation (EGR) the exhaust gas recirculation duct from the exhaust manifold is enclosed.

A method of making the above Exhaust collector consists of the (mechanical or hydromechanical) deep drawing of an originally flat Sheet metal, which creates a tub with molded on it circumferential mounting flange and a pipe socket Is formed, the punching out or Cut the flange contour and open the Pipe approach and welding an outlet pipe flange to the open pipe socket of the exhaust manifold. Deep drawing can also consist of several There are deep-drawing steps. In one of the deep-drawing steps a sealing edge is formed in the mounting flange on the motor side. An advantageous one The method can be further developed during the forming process the formation of a rim area on this flange provide. A suitable welding process is available MAG welding for the stainless steels used. The possibly provided through holes for the Flange fittings can be drilled or punched out his. Through this surprisingly simple and with manufacturing steps associated with little effort cost-effective production possible. Moreover can - especially when using a hydromechanical Thermoforming process - easy adjustments make different engine types of a series.

Another advantageous manufacturing process for Exhaust collector has one or more forming steps to form a trough-shaped structure with integrally connected to the motor side Mounting flange and one-sided pipe attachment on. This is followed by a punching or cutting process, in which the outer contour of the sealing flange as well if necessary, the holes for the flange screw connection and the Pipe attachment are punched out. A circulating or divided loose flange plate is then preferably 5 mm to 10 mm thick made of simple structural steel, with the outer contour and the position of the through holes match those of the sealing flange. After any necessary deburring and The loose flange plate is placed on for cleaning the mounting flange and welding one also deep-drawn outlet flange pipe.

Because there is no welding on the motor-side flange takes place occurs in the described methods in no welding distortion in this area, and that for a easily sealed connections to the cylinder head required accuracy is obtained without further Post-processing achieved.

Fig. 1

eine Seitenansicht einer Ausführungsform eines erfindungsgemäßen Abgassammlers;

Fig. 2

eine auslaßflanschseitige Ansicht des Abgassammlers aus Fig. 1;

Fig. 3

einen Schnitt entlang der Linie III-III aus Fig. 2;

Fig. 4

ein vergrößertes Detail IV aus Fig. 3; und

Fig. 5

einen Schnitt durch den Abgassammler nach Fig.1 im eingebauten Zustand.

The invention is described below with reference to an embodiment in conjunction with the accompanying figures. Show:

Fig. 1

a side view of an embodiment of an exhaust manifold according to the invention;

Fig. 2

an outlet flange side view of the exhaust manifold of Fig. 1;

Fig. 3

a section along the line III-III of Fig. 2;

Fig. 4

an enlarged detail IV of Fig. 3; and

Fig. 5

a section through the exhaust manifold according to Fig.1 in the installed state.

Fig. 1 shows an exhaust manifold with an exhaust manifold 1, a circumferential one-piece molded thereon engine-side mounting flange 2 and an outlet flange 3, which has a flange connector 15 with a molded on the exhaust manifold 1 pipe extension 4 is connected by a weld 6. The engine side Mounting flange 2 has in its peripheral area an all-round erected on-board area 5 that increases its strength. The Fastening flange 2 is included as a sealing flange circumferential sealing edge (see. Fig. 4) executed what the use of an additional seal is unnecessary. On the mounting flange 2 is a loose flange plate 9 put on. The one-piece, closed loose flange plate 9 before welding the Outlet flange 3 placed on mounting flange 2. The longitudinal extent of the exhaust manifold is one Many times larger than its width and depth, which the Design of the exhaust manifold for in-line and V-engines corresponds. In the latter, however, there are two exhaust gas collectors with mirror flanges to use.

Fig. 2 shows the exhaust manifold acc. Fig. 1 from the direction of the outlet flange 3, which has a triangular shape Floor plan with three through holes 7 for fastening screws having. Furthermore, the engine side Fastening flange 2 shown, the outer contour each at the positions of the through holes 8 for the flange screw connection has protrusions. On the outer edge of the mounting flange 2 is the on-board area 5 shown, the mounting flange in addition Stiffness gives.

Fig. 3 shows a section along the line III-III from Fig. 2 by the exhaust manifold. In addition to the Exhaust manifold 1 with the engine-side mounting flange 2, its rim area 5 and the weld seam 6 and the outlet flange 3 on the engine side Mounting flange 2, loose flange plate 9 shown. In the sectional view is also a Loose flange plate 9 and the mounting flange 2 aligned through hole 8 for one Flange screw recognizable. The outlet flange 3 with the Flange connection 15 is made in this embodiment made of the same material as the exhaust manifold 1, the wall thickness of the exhaust manifold 1 .mu.m can be a few tenths of a millimeter smaller. Width B and depth T of the exhaust manifold 1 have approximately that same order of magnitude.

FIG. 4 shows detail IV from FIG. 3, the sealing edge 10, which is shown by a distance t, which is approximately Is 0.5 mm, over the flange level of the motor side Mounting flange 2 protrudes. This lead fulfills a sealing function, creating an additional Seal between the mounting flange on the motor side 2 and engine block can be dispensed with.

Fig. 5 shows a section through the exhaust manifold and the loose flange plate 9 in the assembled state to one Cylinder head 11 with the intake valve 12 and the exhaust valve 13. The mode of operation of the sealing edge 10 clearly that on the flange of the cylinder head rests sealingly. This will blow off the hot exhaust gases from the outlet channel 14 avoided. The Exhaust collector shows compared to the prior art a cross-section with shallow depth, whereby the Pipe attachment with the outlet flange 3 streamlined diagonally and not vertically as in the prior art is attached to the outlet duct 14. When assembling the exhaust manifold only with the threaded holes in the Exhaust flange of the cylinder head 11 brought into congruence become. Then the on the motor side mounting flange 2 attached loose flange plate with specified Screwed torque. Then that will Exhaust pipe, not shown, with the outlet flange 3 connected.

Claims (14)

1. An exhaust manifold for an internal combustion engine with an exhaust collector pan (1), an engine side mounting flange (2), covering several cylinder outlet ports, and an outlet connection (15) comprising an outlet flange (3),
   characterised in that
   the exhaust collector pan (1) and the engine side mounting flange (2) form an integral sheet component, the engine side mounting flange (2) being one piece with the exhaust collector pan (1) with its edge produced by moulding the sheet metal, a sealing edge (10) being moulded in the engine side mounting flange (2) to provide tight contact between the engine side mounting flange (2) and the cylinder head.
2. An exhaust manifold according to Claim 1,
   characterised in that
   the engine side mounting flange (2) has a built up all-round rim area (5).
3. An exhaust manifold according to Claim 1 or 2,
   characterised in that
   a loose flange plate (9) extending all-round is placed on the side of the engine side mounting flange (2) away from the cylinder head
4. An exhaust manifold according to one of the Claims 1 or 2,
   characterised in that
   a split loose flange plate is placed on the side of the engine side mounting flange away from the cylinder head.
5. An exhaust manifold according to Claim 3 or 4,
   characterised in that
   the loose flange plate (9) is 5 mm to 10 mm and preferably 8 mm thick.
6. An exhaust manifold according to one of the Claims 1 to 5,
   characterised in that
   the wall of the exhaust collector pan (1) is 1.8 to 2.5 mm and preferably 2 mm thick.
7. An exhaust manifold according to one of the Claims 1 to 6,
   characterised in that
   the exhaust collector pan (1) is made of a multi-layer metal panel such as sandwich panel consisting of two layers of metal with an inlay arranged in between.
8. An exhaust manifold according to one of the Claims 1 to 7,
   characterised in that
   the cross section of the exhaust collector pan (1) is constant over its length.
9. An exhaust manifold according to one of the Claims 1 to 7,
   characterised in that
   the cross section of the exhaust collector pan (1) widens in the direction of the outlet.
10. An exhaust manifold according to one of the Claims 1 to 9,
    characterised in that
    the outlet flange (3) is arranged at one of its ends in the longitudinal direction.
11. An exhaust manifold according to one of the Claims 1 to 10,
    characterised in that
    on internal combustion engines with exhaust gas recirculation (EGR), the EGR pipe is enclosed by the exhaust collector pan (1),
12. A process of manufacturing an exhaust manifold comprising the following stages:

    deep drawing of an originally flat piece of sheet metal in which a pan with an engine side mounting flange is formed all round it with a sealing edge and a connection pipe at it;

    blanking or trimming the outline of the flange and opening the connection pipe;

    welding an outlet pipe flange on to the opened connection pipe at the exhaust collector pan.
13. A process of manufacturing an exhaust manifold as in Claim 12,
    characterised in that,
    in addition, an all-round built up edge area is formed at the engine side mounting flange during the deep drawing operation.
14. A process of manufacturing an exhaust manifold,
    consisting of the following stages:

    deep drawing of a flat piece of sheet metal, in which a pan with an all-round engine side mounting flange with a sealing edge and a connection pipe shaped at it is formed;

    blanking or trimming the outline of the flange and opening the connection pipe;

    making an all-round or a split loose flange plate;

    fitting the loose flange plate to the mounting flange, on its side away from the cylinder head;

    welding an exhaust pipe flange to the connecting pipe on the exhaust manifold.

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