This application claims the priority, under 35 U.S.C. ยง119, of German application DE 10 2006 024 269.6-13, filed May 24, 2006; the prior application is herewith incorporated by reference in its entirety.
The invention relates to an exhaust system for a motor vehicle, with an exhaust tailpipe cover which can be placed onto exhaust pipes and disposed in a cutout of a vehicle rear part.
Published, non-prosecuted German patent application DE 10 355 472 A1 discloses an exhaust tailpipe cover for an exhaust system of a motor vehicle, which exhaust tailpipe cover has an exhaust pipe with an inner pipe which is pushed onto it and deflects the exhaust gas flow downward toward the carriageway surface. The inner pipe is surrounded by a cover pipe.
It is accordingly an object of the invention to provide an exhaust system which overcomes the above-mentioned disadvantages of the prior art devices of this general type, which has an exhaust tailpipe cover which is exposed to as little thermal loading as possible and avoids transmitting heat to a surrounding vehicle rear part, in particular made of plastic.
With the foregoing and other objects in view there is provided, in accordance with the invention, an exhaust system for a motor vehicle. The exhaust system contains two exhaust pipes, a holding device, and an exhaust tailpipe cover supported by the exhaust pipes and disposed in a cutout of a vehicle rear part. The exhaust tailpipe cover is connected to at least one of the exhaust pipes via the holding device. Two individual inner exhaust pipes are disposed in each case between the exhaust tailpipe cover and the exhaust pipes and plugged onto the two exhaust pipes. The individual inner exhaust pipes are connected fixedly to the exhaust tailpipe cover and together create a continuous passage formed all a way around between the two individual inner exhaust pipes and the exhaust tailpipe cover accommodating them.
The advantages primarily achieved by the invention relate in that, by providing an air gap insulation between the inner exhaust pipes directly guiding the exhaust gas and an exhaust tailpipe cover, a direct transmission of heat to the exhaust tailpipe cover is avoided and therefore also the vehicle rear part made of plastic is not exposed to excessive thermal loading. This takes place by the exhaust tailpipe cover being connected to one or two exhaust pipes of the exhaust system via a holding device, and individual inner exhaust pipes being disposed in each case between the exhaust tailpipe cover and the exhaust pipes and being held such that they are plugged onto the two exhaust pipes and being connected fixedly to the exhaust tailpipe cover, with a continuous passage being formed all the way around between the two inner exhaust pipes and the exhaust tailpipe cover accommodating them. In the driving state, the passage can therefore act in a heat-regulating manner on account of air flowing through it.
So that a stable connection is provided between the exhaust pipes and the exhaust tailpipe cover, it is furthermore provided according to the invention that the holding device is fastened between the two exhaust pipes or else to only one exhaust pipe and a protruding holding tongue of the holding device is disposed in a vertical center plane of the two exhaust pipes, which holding tongue can be pushed into a groove-type receptacle, for example a T-groove-type receptacle, of the exhaust tailpipe cover and is held via a fastener. A threaded nut is fastened on the protruding holding tongue, and a threaded screw can be guided in a bore of the exhaust tailpipe cover to the threaded nut on the holding tongue and can be connected to the threaded nut. The threaded screw is fitted from the lower side of the exhaust system and also a laterally secure support is ensured via the interlocking holding of the holding tongue in the dovetailed receptacle, which is required in particular during vibrations on the exhaust system.
The inner exhaust pipes, which are disposed between the exhaust pipes and the exhaust tailpipe cover and which conduct exhaust gas directly, virtually form an extension of the exhaust pipes. The two inner exhaust pipes have a plurality of outwardly prestressed, resilient clamping elements on their outer circumferential surfaces, which clamping elements, when inserted in the exhaust tailpipe cover, are supported in a manner held by the inner wall and bring about a fixed connection to the exhaust tailpipe cover via screwing measures.
According to the invention, in order to fasten the two inner exhaust pipes in the exhaust tailpipe cover, mutually facing, protruding supporting limbs are fastened to the outer circumferential surface of the two inner exhaust pipes and, when introduced into the exhaust tailpipe cover, are supported, for example, on stops disposed adjacent to the groove-type receptacle and are secured via the screwing measures. The effect thereby advantageously achieved, according to the invention is that the inner exhaust pipes are connected fixedly to the exhaust tailpipe cover, and therefore no contact with the inner wall of the exhaust tailpipe cover can occur, even due to vibrations which occur.
Furthermore, the two inner exhaust pipes together with the two exhaust pipes can be plugged on directly by a widened pipe portion, and those free ends of the two inner exhaust pipes which face away from the widened pipe portion have, all the way around, an air gap with respect to the inner circumferential surface of the exhaust tailpipe cover at the discharge region of the exhaust gases. Removal of the exhaust gases of the internal combustion engine is therefore possible by the exhaust pipes via the inner pipes without the latter coming into contact with the exhaust tailpipe cover.
The inner exhaust pipes are each configured in the discharge region such that they widen in a trumpet-shaped manner, and an air gap is formed between the mouth regions of the exhaust tailpipe and the mouth regions of the inner exhaust pipes, with the inner exhaust pipes each being disposed continuously in the exhaust tailpipe cover at a distance from the inner wall, and the passage being produced. The passage between the inner exhaust pipes and the exhaust tailpipe cover can give rise, in the driving mode, to an air throughflow and, resulting therefrom, to heat being conducted away from the inner exhaust pipes which are heated by exhaust gases. In particular, if the exhaust tailpipe cover is painted, it is not damaged by thermal loading.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in an exhaust system, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
Referring now to the figures of the drawing in detail and first, particularly, to
The exhaust pipe 2 and the adjoining exhaust pipes 3, 4 are connected to the exhaust tailpipe cover 7 via a holding device 10 (
For this purpose, the holding tongue 11 has a fixed threaded nut 13 into which the fastening screw 14 is screwed, for which purpose the latter is inserted into a bore 15 of the exhaust tailpipe cover 7.
Furthermore, the inner exhaust pipes 5, 6 are connected to the exhaust tailpipe cover 7, for which purpose the inner exhaust pipes 5, 6 have, on their outer circumferential surface, two opposite supporting brackets 16, 16a which, when pushed into the exhaust tailpipe cover 7, are supported on steps disposed on a side of the receptacle 12 which can be secured in the steps via screws 17, 18. For a spaced-apart mounting in the exhaust tailpipe cover 7, a plurality of resilient clamping elements 19 are disposed distributed over an outer circumference of the inner exhaust pipes 5, 6 (see
So that the exhaust gas flow P can flow via the exhaust pipe 2 and the adjoining exhaust pipes 3, 4 into the inner exhaust pipes 5, 6, the latter have a tight connection to the exhaust pipes 3, 4. Their tight connection contains in each case a widened pipe portion 20, into which an opposite pipe end 21 of the exhaust pipes 3, 4 can be plugged.
The inner exhaust pipes 5, 6 are disposed in the exhaust tailpipe cover 7 in such a manner that an air passage K running all the way around is formed between the inner exhaust pipes 5, 6 and the exhaust tailpipe cover 7, and therefore, in the driving mode, an air throughflow can take place so that removal of heat is ensured and the exhaust tailpipe cover 7 is no longer exposed to any substantial radiation of heat and the vehicle rear part is kept largely free from harmful effects of heat.
The exhaust tailpipe cover 7 can be composed, for example, of an aluminum casting or of a sheet-metal part, with it being possible for the inner exhaust pipe 5, 6 to be composed of special steel, for example, titanium.
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10 2006 024 269 | May 2006 | DE | national |
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