DE2930730A1 - Hot gas conduit assembly - consists of composite aluminium hollow body with sheet steel end and gas impinges on steel deflector - Google Patents

Abstract

The composite aluminium hollow-body, sheet-steel closure, hot gas conduit, is basically as in 28 04 875. It comprises a one-piece elongated, partitionless aluminium extrusion plus mild- or alloy-steel sheet end pieces configured to complete space enclosure and cause a thermal down-gradient in gas flowing from inlet to outlet. The aluminium extrustion, is externally finned. It is shaped to leave an annular space (10) between it and a cylindrical or other sectional shape steel inner pipe. Holes (12) in the pipe (1) at the devices inlet allow some gas to flow into that space, impinging first on delfecting surfaces of the steel end piece (7). The flow paths recombine via holes (13) in the outlet end piece (8).

Description

description

In the construction application P 28 04 875.1 is a system of thermal Hot gas duct has been described whose constructive idea is elongated Hollow sections that do not have. Have transverse walls to enclose in closing body, which either consist of heat-resistant materials or in some other way the space-forming ones Have impact walls, which on the one hand have the necessary higher fatigue strength compared to aluminum walls and on the other hand the order of the hot gas throughput depending on the application, whereby in each case there is a thermal gradient between the inlet and the outlet from the device is achieved. A number of additional registrations carried out the further training of this system; are particularly mentioned here P 28 38 611.0 and P 29 27 679.7. In the former, a so-called direct hot gas short-circuit path introduced, which consists in the fact that the device incoming hot gas is divided into two different conduction paths, by which one branches off into a partial flow group of the bottom profile, while the other the hot gas is fed directly to the outlet closing body and thus an e.g. made of aluminum Manufactured hollow profile thermally relieved. In the latter is a new type of composite element Hollow profile / closing body shown, with which closing body and corresponding Nohl profile ends can be rigidly attached to each other and a very manufacturing process simple solution to the expansion problems associated with different materials is achieved, which always occur when hot gas throughput takes place. The present Additional registration is closely related to these two system refinements with regard to their claims 1 to 5. Claims 6 ff. represent an extension of the aspect set out in claim 6 of the Hauntanmelaung in relation to the implementation of hot gas pipes through, in particular, aluminum-limited interior spaces of hollow profiles is described and extends the measures outlined there by a porous and perforated sheet metal Material as used in silencers Absorption attenuation is known: it is not a fully insulating intermediate layer follows its gas permeability and causes a thermally equalized heat application the inner aluminum walls.

The structural arrangement in relation to claims 1 to 5 of these Additional registration is shown in FIG. Your task is to for the silencer groups between the engine outlet and largely made of aluminum necessary thermally sloping gas guide to create a cooling section, be which the extraordinary thermal conductivity of aluminum is used, although in the Limiting loads of such exhaust gas routing from internal combustion engines Hot gas temperatures occur at the level where aluminum has its melting point. to For this purpose, an annular space (10 in Figure 1) is formed, which carries the hot gas Steel tube (1) surrounds. In its entirety, this annulus consists of an interior the steel tube shape-like, so tubular aluminum hollow profile, which according to claim 1 of the main application without a transverse wall and enclosed in a sheet steel-limited closing body is: in an inlet closing body (7) and an outlet closing body (8). In A defined partial flow of hot gas is branched off into the annulus, namely in the way that hot gas jets from perforations (12) of the Sthalrohrwandung them act on the opposite sheet steel wall of the inlet closing body (7) and then pass the entire annular space (10) with a change in direction without in During this process, aluminum walls (3) are exposed to a baffle wall. A limited amount of gas is passed through the annular space by the passage of hot gas a contained heat accumulation of the surrounding aluminum body, the is designed so that (see claim 3) that is exposed to the direct application of heat Aluminum wall is only slightly larger than the inner sheet steel border of the annular space (10), whereas the wall surface exposed to the free atmosphere of the aluminum hollow profile, in particular by means of ribs, which step around a dustpan. At the limit of the greatest thermal load, measured as the gas temperature inside the steel pipe (1) opposite d @ Openings (12) is the sum of the flow cross-sections (12) determines the multiplier by which (cf. claim 3) the abstraction range of the hollow profile exceeds the circumference of the annular space walls, and the length of the Aluminum hollow profile body. The amount of gas arriving at the outlet closing body occurs with heat loss through the openings (13) downstream into the steel pipe again and that measured in the steel pipeline before the openings 12 and after the openings 13 The difference is applied to the cooling effect of this system. An ejector arrangement the openings 13 (see. Claim 4) causes an increasing flow rate in the steel pipe has a corresponding effect in the annular space (10). The advantage of such a cooling section is that radiator-like assemblies that require a large installation space make, are not required and the characteristics below the vehicle an elongated pipe of the usual type is retained. Also from the Thermal radiation emanating from the outer surface of the cooling fin tube is distributed. The annulus system at the same time fulfills the requirements for front silencers for vehicle exhaust pipes are usually placed within these lines and distribute their volume accumulations for a longer distance. Regarding the AD beam size that can be achieved the benefits are even more drastic. An example in a circular cylindrical calculation : a steel pipe (1 in Figure 1) with an outside diameter of 45 mm is selected and the outer boundary of the annular space (10), i.e. the aluminum tube, with an internal diameter of 56 mm, for example, ribs with a rib height of 10 mm (5 in FIG. 1) already have a rib Radiation range achievable, which corresponds approximately to an outer cylinder with a diameter of 200 mm. Are ribs around an aluminum tube similar in shape to the steel tube in an oval space requirement laid out, so the height of such a body smoked, that is, the lowest height of their oval section should not be more than about 60 mm.

The structural arrangement in relation to claims 6 to 10 becomes shown in Figures 2 to 5. For this is how in the preamble of the claim 6 expressed, above all the decisive point of view, according to a cooling path arrangement according to claims 1 to 5 in the provided up to the exit into the free atmosphere sound-absorbing follow-up groups to use those constructive simplifications that are possible if the exhaust gas enters these downstream groups with a lower temperature.

In addition, for such simplifications there is the fact that the Cooling section arrangement according to claims 1 to 5 at the same time a sound-absorbing effective Construction in the sense of known pre-sound absorbers in that (cf.Fig 1) A partial amount of gas branched off at the perforations 12, reflections on the impact wall 7 and other acoustically effective measures.

FIG. 2 shows such a simplification through an extremely lightweight construction by means of an only single-walled aluminum housing 7, for which the closing body 7 and 8 within the meaning of claim 1 of the main application P 28 04 875.1 for space formation required additional walls, in particular the transverse walls 24 and 22 contain. The claim 6 brings for such an inexpensive lightweight construction as a conductive Point of view of thermal gas flow to the expression, the hot gas inlet from one Inlet pipe 1 and a relaxation space 17 provided in the closing body 7 into a Make supply pipe group 18, from which the hot gas only in the downstream Part of the aluminum-limited interior 19 is released. In addition, that this amount of hot gas released into the downstream part of the space 19 only after reversal of the outwardly radiating walls of the closing body 8 in the upstream Part of the aluminum-limited space 19 runs back, wherein, as in addition from Figure 2 can be seen, a heat emission to the muffler outlet pipe 2, namely on its outer wall takes place; the amount of heat given off becomes the Free atmosphere is supplied without a detour and thermally relieves the single-walled ones Aluminum housing body 3. If this figure 2 is considered in the sense of claim 6, so is the insulation material drawn in it 20 eirschlie ~ i not to include its perforated sheet metal bracket 21 in the concept, because it represents in the H en special conditions represent an additional measure according to claim 8. The Claim 7 expresses that the aspect represented in claim 6 is thermal gas flow with the acoustic known from sound absorption technology Chain ladder, especially in an overlapping design, achieve good measurements.

FIG. 3 provides a complementary conceptual context this additional application already claims from the main application P 28 04 875 1, 2 and 4 known construction, in which a double-walled aluminum hollow profile is used (3), the implementation of Figure 1 of P 28 04 875, but also Figures 7, 8, 9 and 13 corresponds. There is a double countercurrent arrangement with him of the gas throughput provided, namely in the channel groups 25 and 26 with each other and at the interior throughput (27) compared to the channel group 26. Claim 9 brings with reference to this only the possibility of an additional inner lining of the space 27 with absorption material of a known type expressed.

In a manner similar to that of FIG. 3, FIG. 4 already brings one Construction represented by an earlier application in this context: In the patent application P 28 40 200.8 has been shown how to inexpensive Wise partial flow formations within sound-absorbing devices have thereby been achieved can nen that hollow profile lines made of aluminum, especially those with ribs are provided, arranged in a form-fitting manner in the interior of other hollow profile lines can be that, as Figure 5 shows, even enclosing the entire circumference Bundles of partial flow groups arise. In this respect, FIG. 4 is also an addition the construction of Figure 2, in which pipes for such a partial flow group (18) can be used. These tubes 18 of Figure 2 are with the partial flow lines 6 of FIGS. 4 and 5 are comparable. The related claim 10 relates only on the positioning of the absorption material around the perforated sheet metal cylinder 28 of the outlet pipe.

L e r s e i t e

Claims (10)

Name of the application: Composite systems aluminum hollow profiles with Sheet steel closing bodies Additional application to P 28 04 875.1 Patent claims 1. Guide system for hot gas throughput as a feed line to an exhaust system according to claims 1 and 10 of the main application P 28 04 875.1 by means of a single-walled elongated aluminum hollow profile without transverse walls, enclosed in a closing body made of simple or refined sheet steel, which have the additional walls required for space formation and the gas flow rate arrange as a thermal gradient between the inlet and outlet closing body, characterized in that an approximately cylindrical or profile-like steel tube of one in relation to the opposite wandur £; shape-like aluminum tube, which is sent with cooling fins on the outside, is surrounded at a distance in the way (see Fig 1) that between the two forms an annular space (10) from which the hot gas is supplied Steel pipe (1) via a sheet steel inlet closing body (7) a partial amount of hot gas is fed, which after passing through the sheet steel outlet closing body (11 with outer wall 8) in a downstream zone (2) of the steel pipe (1) (holes 1). 2. Device according to the previous claim, characterized in that the outlet openings (12), from which the partial amount of hot gas enters the annular space (10) arrives, are directed at sheet steel baffles of the inlet closing body and not on walls (3) of the aluminum hollow profile, which the annular space (10) as Limit the outer wall. 3. Device according to one of the preceding claims, characterized in that that the aluminum surface delimiting the annular space (10) on the outside with regard to its two-dimensional design that of the opposite steel pipe wall only by the additional amount exceeds that of the larger circumference of the outer wall of a relatively narrow Maintained annulus results, while that of the free atmosphere facing Wall surface of the aluminum hollow profile in particular by ribbing or other Way the area size of the steel pipe inner wall of the annular space (10) by a larger amount times, usually more than three times. 4. Device according to one of the preceding claims characterized in that that in the downstream area of the outlet closing body (11) the outlet opening (s; 13) from the annular space sequence (9/10/11) are arranged in such a way that the flow energy the amount of hot gas passed through the steel pipe (1) against the ejector effect achieved. 5. Device according to one of the preceding claims, characterized in that that the closing body holding the aluminum hollow profile with this on its respective Ends and are firmly connected to the steel pipe and the steel pipe within the Annular space area (zone 16) is divided and interlocking positively The ends form a sliding path that compensates for the expansions. 6. Guide system for the gas throughput of internal combustion engines in the free atmosphere according to claim 1 of the main application P 28 04 875.1, in particular as a sound-absorbing unit of an inlet section of the claims 1 to 5 of these Additional application described downstream, characterized in that (cf. Figure 2) a single-walled hollow profile (3; closing body) enclosed in the closing body 7 and 8) only then with a hot gas inlet fed in from the inlet closing body (7) an admission of its aluminum inner walls experiences when the amount of hot gas only in the downstream part of an interior space (19) delimited by aluminum is a supply pipe group (18) leaves and the amount of hot gas only after reversal at an outward radiating Wall (8) of the outlet closing body in the aluminum-limited upstream Interior part runs back to lUCh there the flow reversal on a sheet steel wall (24) to fully flow towards the outlet pipe (2). 7. Device according to the previous claim, characterized in that let the through the closing body oewir'te gas flow rate order in the form of an overlapping acoustic chain conductor (18/2). 8. Device according to one of claims 6 or 7 characterized -indicated, that the aluminum inner wall with perforated plate-containing porous absorption material is lined, which a uniform heat application of the wall in addition to its sound-absorbing properties (20/21). 9. Device according to claims 1 to 8 of main application P 28 04 875.1 with a double-walled hollow profile (see Bigur t) and a counterflow arrangement within its gas ducts (groups 25 and 26), characterized in that that even with an interior space (27) surrounded on all sides by such counterflow channels a gas-permeable lining according to claim 8 takes place. 10. Device with a partial flow group formed from two hollow profiles (6 in Figures 4 and 5) within a single-walled hollow profile forming the housing (3) characterized in that the lining with norösem material according to claim 8 on the inner wall of a single-walled raw profile or (Figure 4) in known Way as a casing around an outlet pipe (2), with its gas routing path is made of perforated sheet metal in the area of the casing (28).