EP1241330A2 - Method for making an exhaust manifold and exhaust manifold made thereby - Google Patents

Abstract

• Vorfertigen der Teilschalen (3,4,5,6;1,2) der Innenschale und der Außenschale;
• Fixieren jeder Teilschale (3,4;5,6) der Innenschale an einer Teilschale (1;2) der Außenschale;
• Zusammenfügen der Außenschale aus den zugehörigen Teilschalen (1,2)unter gleichzeitigem Zusammenfügen der Innenschale aus den zugehörigen Teilschalen (3,4,5,6);
• Fixieren der Teilschalen (1,2) der Außenschale zueinander unter Ausbildung einer gasdichten Naht.

A method for producing an exhaust manifold having a plurality of exhaust gas inlet openings and at least one exhaust gas outlet opening, the inner shell being composed of at least two partial shells (3, 4, 5, 6), which within one and at least predominantly maintaining a distance from one of at least two partial shells (1,2) assembled outer shell, comprises the following steps:

• Prefabrication of the partial shells (3,4,5,6; 1,2) of the inner shell and the outer shell;
• Fixing each partial shell (3, 4; 5, 6) of the inner shell to a partial shell (1; 2) of the outer shell;
• Assembling the outer shell from the associated partial shells (1, 2) while simultaneously joining the inner shell from the associated partial shells (3, 4, 5, 6);
• Fix the partial shells (1, 2) of the outer shell to one another to form a gas-tight seam.

Description

The present invention relates to a method for Manufacture of a plurality of exhaust gas inlet openings and having at least one exhaust gas outlet opening Exhaust manifold, the one at least predominant Maintaining a distance within an outer shell arranged inner shell includes. It affects an exhaust manifold for an internal combustion engine with a plurality of exhaust gas inlet openings and at least one exhaust gas outlet opening an outer shell and one inside of this at least predominantly maintaining a distance Inner shell.

Due to constantly changing requirements for exhaust manifolds for internal combustion engines has been in the past Years of preferred construction and manufacturing constantly changing. At first they were in use cast manifolds. As part of the targeted Reduction of vehicle weight to save fuel became their comparatively high weight recognized as disadvantageous; the development then went in Direction towards built manifolds, mainly in the form of Cup elbows, which consist of two welded together, half shells made of sheet metal joined together (compare e.g. EP 818616 A1, US 6,018,946 A and US 4,930,678 A). As part of the equipment from Motor vehicles with catalytic emission control devices then got with regard to a favorable starting behavior a reduction of the catalyst Heat losses in the area of the exhaust manifold Significance. This resulted in the development of double-shell exhaust manifolds with an inner shell and an outer shell, the inner shell at least predominantly, i.e. of apart from individual contact surfaces, a distance to the outer shell. Although by that distance Strictly speaking, the space between is regularly included Exhaust gas is filled, such manifolds are common referred to as air gap insulated (LSI) manifolds. a Relevant prior art form the EP 0717179 B1, US 5,768,890 A and EP 0955453 A2; also JP 07042547, EP 0779418 A1 and DE 4339290 A1 are relevant in this regard. For the production corresponding LSI manifolds come in combinations of different ones Procedure for use. All known LSI manifolds can be used independently of the specific manufacturing method with only one produce considerable manufacturing effort.

Regardless of the development line outlined above has already been proposed (see DE 3333591 A1) to manufacture an exhaust manifold by a formed from two welded half shells Inner shell also in two half shells molded thermal insulation shell is embedded, which in turn then in one of two half shells existing outer shell is inserted, the two half shells of the outer shell finally with each other be welded. Background for this development was a targeted reduction in heat radiation of the exhaust manifold to reduce heat generation in encapsulated engine compartments. That encapsulation the engine room was again a measure to reduce of air resistance, which in turn becomes a Reduction in fuel consumption should help.

The object of the present invention is one inexpensive with little manufacturing effort manufacturable LSI manifold and one for its manufacture to find a suitable method. It should be preferred also the risk that the exhaust gas-carrying parts Weld spatter stick, which occurs when operating the engine get into the downstream components of the exhaust system and can do damage there, reduced become.

This task is solved according to the present Invention by the method specified in claim 1. One made in accordance with the present invention Exhaust manifold is specified in claim 3. For the present invention is therefore important that both the outer shell and the inner shell from at least two partial shells are put together, each partial shell of the inner shell before assembly the outer shell from the associated partial shells fixed to a partial shell of the outer shell becomes. According to the present invention, therefore, is not first put the inner shell together and then the outer shell is assembled around this. Rather, due to the fixation of the partial shells the inner shell on a partial shell of the outer shell the inner shell and outer shell at the same time the associated partial shells put together. It does not apply in this way in particular the one with the isolated assembly the inner shell from the associated partial shells associated effort. In addition, what can also reduces costs, all components of the exhaust manifold according to the invention as inexpensive Execute deep-drawn parts.

The correct positioning of the partial shells of the inner shells in the assigned partial shells of the outer shell usually takes place via a (locally limited) Installation of the inner shell on the outer shell in those areas where the exhaust gas enters the inner shell or exits from this. In this context it should be noted that the present invention is by no means imperative that the inner shell extends over the entire extent of the outer shell; rather, the inner shell can also open up restrict a portion of the outer shell, such as how this is already known from EP 0717179 B1 (FIG. 1) is.

For fixing the partial shells of the inner shell to the assigned partial shells of the outer shell before assembling the outer and inner shell is suitable in particular a hole weld, each weld from the outer shell in the area of one in the concerned Partial shell of the outer shell arranged recess he follows. With such a hole weld in addition to the comparatively little effort, the special Advantage associated that no weld spatter on the exhaust gas-carrying surfaces of the inner shell of the exhaust manifold can reach, so that the risk of being detached Welding spatter downstream components of the Damage the exhaust system, significantly reduced if is not completely excluded.

Another preferred development of the invention Exhaust manifold is characterized in that the at least one outlet opening within a partial shell the outer shell is arranged. With this training in other words, the division of the Outer shell not through the outlet opening. Again, this is in terms of reduction the risk of downstream components of the exhaust system damaged by detached welding spatter be particularly cheap.

From the same point of view, it is particularly advantageous if each of the inlet openings of the invention Exhaust manifold within a part of the shell Outer shell is arranged, i.e. the division of the outer shell does not pass through the inlet openings. A particularly preferred development of the invention is characterized in that all Inlet openings and the at least one outlet opening arranged in the same shell of the outer shell are.

In no way within the scope of the present invention mandatory that the number of partial shells of the inner shell corresponds to the number of partial shells of the outer shells. For example, as below in the context of the description of a preferred embodiment in detail, for a four-in-one manifold the inner shell from four partial shells and the outer shell is assembled from two partial shells his. A comparable structure of the invention Exhaust manifold would also be in a four-in-two arrangement, for example possible.

Yet another preferred development of the invention Exhaust manifold is characterized by this from that the opposing partial shells the inner shell in the area of the parting plane overlap. In this way, a relatively high Achieve a level of gas tightness of the inner shell. Especially at least one of the two is preferred overlapping edge areas of the opposing Partial shells of the inner shells beveled. The favor resulting guiding slopes the fitting of the partial shells of the inner shell when manufacturing the exhaust manifold.

To support the cohesion of the partial shells of the Inner shell in the assembled exhaust manifold can the opposing partial shells of the inner shell with each other by means of a clamp, snap or Snap connection be connected, which when assembling the relevant partial shells of the inner shell locked.

Fig. 1

in perspektivischer Ansicht schräg von oben die untere Teilschale der Außenschale;

Fig. 2

die Außenschale gemäß Fig. 1 mit zwei in diese eingelegten und an dieser fixierten Teilschalen der Innenschale und

Fig. 3

in perspektivischer Ansicht die untere und die obere Teilschale der Außenschale mit den jeweils zwei an diesen fixierten Teilschalen der Innenschale unmittelbar vor dem Zusammenfügen der Innenschale und der Außenschale.

Fig. 4

veranschaulicht in perspektivischer Ansicht die zusammengefügte Innenschale des Abgaskrümmers gemäß den Figuren 1 bis 3.

The present invention is explained in more detail below on the basis of an exemplary embodiment illustrated in the drawing. The drawing illustrates a four-in-one manifold, the outer shell of which is composed of two partial shells and the inner shell of four partial shells. It shows

Fig. 1

in a perspective view obliquely from above the lower shell of the outer shell;

Fig. 2

the outer shell according to FIG. 1 with two partial shells of the inner shell inserted into and fixed to this

Fig. 3

in perspective view, the lower and the upper partial shell of the outer shell with the two partial shells of the inner shell fixed to them immediately before the inner shell and the outer shell are joined.

Fig. 4

illustrates in perspective view the assembled inner shell of the exhaust manifold according to FIGS. 1 to 3.

The exhaust manifold shown in the drawing includes an outer shell, which is composed of two partial shells 1, 2 and an inner shell made of a total of four partial shells 3, 4, 5, 6 is joined. It is a four-in-one manifold with four Exhaust gas inlet openings 7 and an exhaust gas outlet opening 8. All four exhaust gas inlet openings 7 and the exhaust outlet 8 are completely inside the lower shell 1 of the outer shell. The exhaust gas inlet openings 7 are exhaust gas inlet connections 9 assigned; in a corresponding manner is the exhaust outlet 8 an exhaust outlet 10 assigned. This makes it possible to attach to the outer shell of the manifold on the inlet side and outlet side Flanges to weld, the connection of the manifold with the neighboring components of the exhaust system or Serve cylinder head.

Act on all six components of the exhaust manifold it is deep-drawn parts made of sheet metal. The partial shells 3, 4, 5 and 6 of the inner shell are included made from a heat-resistant steel sheet.

As part of the production of the exhaust manifold two partial shells 3 and 4 of the inner shell in the lower Partial shell 1 of the outer shell inserted, as in Figure 2 is illustrated. You are just lying there adjacent to the exhaust gas inlet openings 7 and the exhaust gas outlet opening 8 and in the area of the two cutouts 11, the bulge-shaped inward Elevations are surrounded on the lower part of the shell Outer shell on; otherwise the partial shells 3 and 4 of the inner shell to the lower shell 1 of the outer shell a distance so that there is a "Air gap insulation" between the inner shell and the Outer shell results. The two partial shells 3 and 4 of the Inner shell will be after you get into the lower part shell 1 of the outer shell have been inserted, by means of each a hole weld from the outside of the lower one Partial shell 1 of the outer shell welded to it, the corresponding welds extend along the recesses 11.

The two partial shells 5 and 6 of the inner shell in the correct position with the upper one Partial shell 2 of the outer shell connected by appropriate Hole welds through the recesses 12 of the upper part shell 2 of the outer shell executed become.

In the next manufacturing step (see FIG. 3) the two pre-assembled modules 13 and 14 placed on one another. At the same time, the inner shell as well as the outer shell from the corresponding Partial shells put together. In conclusion, the upper part shell 2 and the lower part shell 1 of the outer shell by means of a circumferential weld seam with each other connected, the outer shell by means of that The weld seam is closed gas-tight. In contrast is the inner shell is not gastight. This means, it may well be through appropriate slots and gaps Exhaust gas that through the exhaust gas inlet openings 7 in the manifold enters the space between the Inner shell and the outer shell. However is the gas exchange in this area is so low that the Heat radiation to the environment is only slightly larger is compared to those exhaust manifolds where (also) the inner shell is gastight.

The conditions are illustrated in detail in FIG when the inner shell is joined together one of the exhaust gas inlet openings 7 opposing partial shells 3 and 5 of the inner shell each other on the edge. Here is the edge area 15 of the lower shell 3 of the inner shell in the area of overlap with the assigned upper Partial shell 5 of the inner shell bevelled towards the outside. In this way, guide bevels 16 arise which when assembling modules 13 and 14 the fitting together of the opposing ones Favor partial shells of the inner shell or support.

Claims (11)

Method for producing an exhaust manifold having a plurality of exhaust gas inlet openings (7) and at least one exhaust gas outlet opening (8), which has an inner shell which is composed of at least two partial shells (3, 4, 5, 6) and which within and at least largely maintains a distance an outer shell composed of at least two partial shells (1, 2) is arranged, comprising the following steps: Prefabrication of the partial shells (3,4,5,6; 1,2) of the inner shell and the outer shell; Fixing each partial shell (3, 4; 5, 6) of the inner shell to a partial shell (1; 2) of the outer shell; Assembling the outer shell from the associated partial shells (1, 2) while simultaneously joining the inner shell from the associated partial shells (3, 4, 5, 6); Fix the partial shells (1, 2) of the outer shell to one another to form a gas-tight seam. Method according to claim 1, characterized in that the partial shells (3, 4; 5, 6) of the inner shell on the assigned partial shell (1; 2) of the outer shell by means of a welded hole with a recess (11) made in the relevant partial shell of the outer shell ; 12) drawn weld seam can be fixed. Exhaust manifold for an internal combustion engine with a plurality of exhaust gas inlet openings (7) and at least one exhaust gas outlet opening (8), comprising an outer shell and an inner shell arranged within this with at least predominantly maintaining a distance, the outer shell and the inner shell each consisting of at least two partial shells (1, 2; 3,4,5,6) are joined together, characterized in that each partial shell (3,4; 5,6) of the inner shell is firmly connected to a partial shell (1; 2) of the outer shell. Exhaust manifold according to claim 3, characterized in that each partial shell (3, 4; 5, 6) of the inner shell is connected to the assigned partial shell (1; 2) of the outer shell by means of a welded hole made from the outer shell. Exhaust manifold according to claim 3 or claim 4, characterized in that the at least one outlet opening (8) is arranged within a partial shell (1) of the outer shell. Exhaust manifold according to one of claims 3 to 5, characterized in that each of the inlet openings (7) is arranged within a partial shell (1) of the outer shell. Exhaust manifold according to claim 5 and claim 6, characterized in that all the inlet openings (7) and the at least one outlet opening (8) are arranged within the same partial shell (1) of the outer shell. Exhaust manifold according to one of claims 3 to 7, characterized in that in a four-in-one design the inner shell is composed of four partial shells (3, 4, 5, 6) and the outer shell is composed of two partial shells (1, 2). Exhaust manifold according to one of claims 3 to 8, characterized in that the opposing partial shells (3, 5; 4, 6) of the inner shell overlap one another at the edge. Exhaust manifold according to claim 9, characterized in that at least one of the overlapping edge regions (15) of the opposing partial shells (3, 5; 4, 6) of the inner shell is chamfered to produce guide bevels (16). Exhaust manifold according to claim 9 or claim 10, characterized in that the opposing partial shells (3, 5; 4, 6) of the inner shell are connected to one another by means of a clamp, snap or snap connection.

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