Exhaust pipe

Abstract

A pipe (11), carrying exhaust gas, of an exhaust system (1) of an internal combustion engine (9), with a tubular body (15) carrying exhaust gas, and with at least one attachment part (12) separate with respect to the tubular body (15), which is added laterally to the tubular body (15) so that externally on the tubular body (15) a cavity (13) is arranged delimited at least partially by the attachment part (12), which extends in the circumferential direction (14) of the tubular body (15) over less than 360.

Claims

1. An exhaust gas carrying pipe of an exhaust system of an internal combustion engine, the exhaust gas carrying pipe comprising: a tubular body carrying exhaust gas; and an attachment part separate with respect to the tubular body, the attachment part being disposed laterally to the tubular body whereby externally on the tubular body a cavity is arranged delimited at least partially by the attachment part and the cavity extends in a circumferential direction of the tubular body over less than 360, the attachment part adding rigidity to the tubular body and comprising a shell body produced from one piece, the shell body, transversely to a longitudinal extent of the tubular body, has a U-shaped cross-section with two legs connected via a curved portion, the legs being fastened on opposite sides of the tubular body, the tubular body being perforated with a perforation in the region of the attachment part, the attachment part comprises a further tubular body produced from one piece, the further tubular body having a connection portion shaped complementary to an outer wall of the tubular body carrying exhaust gas, to which the further tubular body is connected so that the connection portion and the outer wall lie in a planar contact against one another, the connection portion extending from a respective one of the legs in opposite circumferential directions of the tubular body.

2. A pipe according to claim 1, wherein the cavity is closed to an exterior of the exhaust gas carrying pipe.

3. A pipe according to claim 2, wherein the cavity is at least one of fluidically and acoustically connected to an interior of the tubular body.

4. A pipe according to claim 2, further comprising sound-absorbing material wherein the cavity is at least partially filled with the sound-absorbing material.

5. A pipe according to claim 1, wherein: the attachment part is fastened on the tubular body on two sides of the tubular body facing away from one another; the attachment part is fastened on the tubular body on the respective sides of the tubular body by a weld connection; and the weld connection extends in a longitudinal extent of the tubular body along the tubular body.

6. A pipe according to claim 1, wherein the connection portion and the outer wall are perforated in the region of the contact between the connection portion and the outer wall.

7. A pipe according to claim 1, wherein the perforation of the tubular body comprises a plurality of openings, which are adjacent to one another at least one of axially and in a circumferential direction of the tubular body.

8. A pipe according to claim 1, further comprising closure elements wherein the cavity is closed in a longitudinal extent of the tubular body at each end by a respective one of the closure elements.

9. A pipe according to claim 8, wherein at least one of: at least one of the closure elements is fastened on the tubular body; and at least one of the closure elements is fastened on the attachment part or is formed integrally therewith.

10. A pipe according to claim 1, further comprising another attachment part separate with respect to the tubular body, wherein: the tubular body extends in a straight line; and the attachment part and the other attachment part are connected to the tubular body so as to be arranged at least one of in a circumferential direction of the tubular body and in a longitudinal direction of the tubular body and offset with respect to one another on the tubular body.

11. A pipe according to claim 1, wherein: the tubular body extends in a curved shape with a curve; the attachment part is arranged on an inner side of the curve; the attachment part is shaped so that the cavity, in a longitudinal extent of the tubular body is closed at each end by the tubular body itself; the attachment part comprises a shell body produced from one piece, which transversely to a longitudinal extent of the tubular body has a U-shaped cross section with two legs connected via a curve, which legs are fastened at opposite sides of the tubular body; and the two legs, at leg edges remote from the curve of the shell body, are curved in accordance with the curve of the tubular body.

12. An exhaust system according to claim 1, further comprising: an other attachment part separate with respect to the tubular body, the leg of the attachment part and a leg of the other attachment part are fastened on the tubular body by a single weld connection.

13. An exhaust system of an internal combustion engine, the exhaust system comprising: at least one exhaust gas aftertreatment device with an inlet side and with an outlet side; pipe sections carrying exhaust gas, the at least one exhaust gas aftertreatment device inlet side being connected to one of the pipe sections and the at least one exhaust gas aftertreatment device outlet side being connected to another of the pipe sections, wherein at least one of the pipe sections comprises: a tubular body carrying exhaust gas; and an attachment part separate with respect to the tubular body, the attachment part being connected to the tubular body and disposed laterally to the tubular body whereby externally on the tubular body a cavity is arranged delimited at least partially by the attachment part and the cavity extends in a circumferential direction of the tubular body over less than 360, the attachment part adding rigidity to the tubular body and comprising a shell body produced from one piece, the shell body, transversely to a longitudinal extent of the tubular body, has a U-shaped cross-section with two legs connected via a curved portion, the legs being fastened on opposite sides of the tubular body, the tubular body being perforated with a perforation in the region of the attachment part, the attachment part comprises a further tubular body produced from one piece, the further tubular body having a connection portion shaped complementary to an outer wall of the tubular body carrying exhaust gas, to which the further tubular body is connected so that the connection portion and the outer wall lie in a planar contact against one another, the connection portion extending from a respective one of the legs in opposite circumferential directions of the tubular body.

14. An exhaust system according to claim 13, further comprising sound-absorbing material, wherein: the cavity is closed to an exterior of the exhaust gas carrying pipe; the cavity is at least one of fluidically and acoustically connected to an interior of the tubular body; and the cavity is at least partially filled with the sound-absorbing material.

15. An exhaust system according to one of claim 13, wherein: the attachment part is fastened on the tubular body on the respective sides of the tubular body by a weld connection; and the weld connection extends in a longitudinal extent of the tubular body along the tubular body; the connection side and the outer wall are perforated in the region of the contact between the connection side and the outer wall.

16. An exhaust system according to claim 13, further comprising another attachment part separate with respect to the tubular body, wherein: the tubular body extends in a straight line; the attachment part and the other attachment part are connected to the tubular body so as to be arranged at least one of in a circumferential direction of the tubular body and in a longitudinal direction of the tubular body and offset with respect to one another on the tubular body.

17. An exhaust system according to claim 13, wherein: the tubular body extends in a curved shape with a curve; the attachment part is arranged on an inner side of the curve; the attachment part is shaped so that the cavity, in a longitudinal extent of the tubular body is closed at each end by the tubular body itself; the attachment part comprises a shell body produced from one piece, which transversely to a longitudinal extent of the tubular body has a U-shaped cross section with two legs connected via a curve, which legs are fastened at opposite sides of the tubular body; and the two legs, at leg edges remote from the curve of the shell body, are curved in accordance with the curve of the tubular body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings:

(2) FIG. 1 is a greatly simplified schematic diagram, in the manner of a circuit diagram, of an exhaust system with a plurality of exhaust pipes;

(3) FIG. 2 is a greatly simplified cross-section of an exhaust pipe, according to section lines II in FIG. 1;

(4) FIG. 3 is a cross-sectional view, similar to FIG. 2, but showing another embodiment;

(5) FIG. 4 is a longitudinal sectional view of the exhaust pipe according to section lines IV in FIG. 2;

(6) FIG. 5a is a side view of an exhaust pipe showing one of different embodiments;

(7) FIG. 5b is a side view of an exhaust pipe showing another of different embodiments;

(8) FIG. 5c is a side view of an exhaust pipe showing another of different embodiments;

(9) FIG. 5d is a side view of an exhaust pipe showing another of different embodiments;

(10) FIG. 5e is a side view of an exhaust pipe showing another of different embodiments;

(11) FIG. 6a is an isometric view of the exhaust pipe of the embodiment of FIG. 5a;

(12) FIG. 6b is an isometric view of the exhaust pipe of the embodiment of FIG. 5b;

(13) FIG. 6c is an isometric view of the exhaust pipe of the embodiment of FIG. 5c;

(14) FIG. 6d is an isometric view of the exhaust pipe of the embodiment of FIG. 5d; and

(15) FIG. 6e is an isometric view of the exhaust pipe of the embodiment of FIG. 5e.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(16) According to FIG. 1, an exhaust system 1 comprises a plurality of exhaust gas aftertreatment devices 2, an exhaust manifold 3 on the inlet side and a tailpipe 4 at the outlet side. In addition, the exhaust system 1 has a plurality of pipe sections 5, for example in order to connect two exhaust gas aftertreatment devices 2 with one another or in order to connect the exhaust manifold 3 with such an exhaust gas aftertreatment device 2. The exhaust gas aftertreatment devices 2 can be, for example, a catalytic converter 6, a particle filter 7 and a sound absorber 8. Expediently here respectively a housing 35 of the respectively exhaust gas aftertreatment device 2 is connected on the inlet side and/or on the outlet side to such a pipe section 5. In the example of FIG. 1, the tailpipe 4 is connected directly onto the sound absorber 8.

(17) The exhaust system 1 serves for the discharging of combustion exhaust gases from an internal combustion engine 9, which is equipped in addition with a fresh air system 10 for the fresh air supply. Expediently, the internal combustion engine 9, exhaust system 1 and fresh air system 10 are arranged in a motor vehicle, which is not illustrated further here.

(18) In the example of FIG. 1, two of the pipe sections 5 as pipe 11 carrying exhaust gas, which can also be designated below as exhaust pipe 11, are configured as follows. According to FIGS. 1 to 6, such an exhaust pipe 11 comprises a pipe section 15, which in operation of the exhaust system 1 serves for carrying a stream of exhaust gas, and an attachment part 12, which in operation of the exhaust system 1 is not flowed through by exhaust gas, which is a separate component with respect to the tubular body 15 and which is added to the tubular body 15. Here, a geometry of the attachment part 12 and its arrangement on the tubular body 14 are coordinated with one another so that externally on the tubular body 15 a cavity 13 is produced, which is delimited at least partially by the attachment part 12.

(19) As can be seen in particular from FIGS. 2 to 6, the attachment part 12 and the cavity 13 do not extend completely in a circumferential direction 14 of the tubular body 15, i.e. over less than 360 and preferably over a maximum of 180 along the tubular body 15 of the exhaust pipe 11. The tubular body 15 fulfils the exhaust gas carrying function of the exhaust pipe 11 and can therefore also be designated as a tubular body 15 which is flowed through or which carries exhaust gas.

(20) As can be seen in particular from FIGS. 2 and 3, the attachment part 12 is fastened on the tubular body 15 on two sides of the tubular body 15 facing away from one another. In FIGS. 2 and 3 respectively two weld seams 16 can be observed, which fix the attachment part 12 on the tubular body 15. It is particularly advantageous here if the respective weld seam 16, which can also be generally designated as welded connection 16, extends along the tubular body 15 in a longitudinal direction 17 or longitudinal extent 17 of the tubular body 15. The longitudinal direction 17 or respectively the longitudinal extent 17 of the tubular body 15 follows here a longitudinal center axis 18 of the tubular body 15, which can be straight-lined according to the examples of FIGS. 4 and 5a to 5d and 6a to 6d, or can be curved according to the example of FIGS. 5e and 6e. In particular, the respective welded connection 16 can extend over the entire length of the attachment part 12 in the longitudinal direction 17 along the tubular body 15.

(21) According to the embodiment shown in FIGS. 2 and 4, the attachment part 12 can be a shell body 19, which is produced in one piece, i.e. from one piece. The shell body 19 is equipped here with a substantially U-shaped cross-section transversely to the longitudinal extent 17 of the tubular body 15, in which two legs 20 are connected with one another via a curve 21. The legs 20, lying opposite one another, are fastened at opposite sides of the tubular body 15. In addition, in the preferred example which is shown here, the tubular body 15 is perforated in the region of the attachment part 12, i.e. is equipped with a perforation 22, which purely by way of example is formed by a plurality of separate openings 23. Hereby, an interior 24 of the tubular body 15 is coupled acoustically and ultimately also fluidically with the cavity 13. The cavity 13 is not flowed through by the exhaust gas here. The cavity 13 therefore serves as a sound damping chamber, e.g. as an absorption chamber or as a reflection chamber. According to FIG. 4, a sound-absorbing material 25, e.g. metal wool or suchlike, can be arranged in the cavity 13.

(22) According to FIG. 3, the attachment part 12, instead of being configured as a shell body 19, can alternatively be configured as a further tubular body 26, which is likewise expediently produced from one piece or respectively in one piece. This further tubular body 26, in contrast to the tubular body 15 carrying exhaust gas, is not flowed through by exhaust gas and has a connection portion formed of sections 36 and 37 with a connection side 27, which is shaped in a complementary manner to an outer wall 28 of the tubular body 15 carrying exhaust gas. As shown in FIG. 3, the connection sections 36 and 37 extend from the respective leg 20 in opposite circumferential directions of the tubular body 15. With this complementary connection side 27, the further tubular body 26 is added to the outer wall 28 of the exhaust pipe tubular body 15, such that the connection side 27 lies in planar manner against the outer wall 28. Hereby, an intensive heat transmission is achieved between the tubular body 15 carrying exhaust gas and the further tubular body 26 of the attachment part 12. In the example of FIG. 3 a sound absorption function for the exhaust pipe 11 is also provided. For this, the connection side 27 and the outer wall 28 are perforated in the region of the contact between outer side 27 and the outer wall 28. By way of example, the tubular body 15 carrying exhaust gas is again equipped with a perforation 22, which is formed by a plurality of openings 23. In contrast thereto, a perforation 29 of the further tubular body 26 is formed purely by way of example by a single opening 30, which covers the entire region of the perforation 22 of the tubular body 15 carrying exhaust gas. Likewise such a window-like opening may be provided in the tubular body 15 carrying exhaust gas, whilst then the further tubular body 26 has a perforation formed by a plurality of openings. The previously mentioned variant is, however, preferred, owing to the reduced flow resistances. Here, also, through the perforations 22, 29 an acoustic and ultimately also fluidic coupling is created between the cavity 13 and the interior 24.

(23) According to FIG. 4, the cavity 13 can be closed in the longitudinal extent 17 of the pipe 11 or respectively of the tubular body 15 carrying exhaust gas at each of its longitudinal ends or face-side ends respectively by a closure element 31. Hereby, the shaping for the attachment part 12 is simplified. In so far as no perforation 22 is provided, such closure elements 31 are basically not necessary in order to achieve the desired reinforcing of the tubular body 15 carrying exhaust gas or respectively of the exhaust pipe 11. If, however, the cavity 13 is to be used for sound absorption, the cavity 13 must be closed tightly on all sides, apart from the region of the perforation 22. In the example of FIG. 4, the two closure elements 31 are designed both with regard to the tubular body 15 carrying exhaust gas and also with regard to the attachment part 12 as separate components, which are added both to the attachment part 12 and also to the tubular body 15. However, corresponding welded connections or weld seams are not illustrated here. The respective closure elements 31 may be formed integrally on the tubular body 15 or integrally on the attachment part 12.

(24) With reference to FIGS. 5a-5e and 6a-6e, further basic features for other embodiments are now discussed, wherein the features explained below can basically also be combined arbitrarily with the features of the embodiments explained above.

(25) According to the variants of FIGS. 5a, 6a and 5d and 6d, the exhaust pipe 11 is, as a whole, straight-lined. The tubular body 15 therefore extends in a straight manner. In the embodiments of FIGS. 5a, 6a and 5c and 6c, respectively two attachment parts 12 are added to the tubular body 15. In the embodiment of FIGS. 5a and 6a, the two attachment parts 12 are arranged offset to one another on the tubular body 15 in the longitudinal direction 17 of the tubular body 15. In the variants of FIGS. 5a, 6a and 5b, 6b, the two attachment parts 12 are arranged lying diametrically opposite, i.e. offset to one another by 180 in the circumferential direction 14, on the tubular body 15. This makes it possible, in particular, to fix the two attachment parts 12 on the tubular body 15 via shared weld seams 16.

(26) In the embodiments shown in FIGS. 5a, 6a; 5b, 6b; and 5c, 6c, the attachment parts 12 are respectively dimensioned to be of equal size in the longitudinal direction 17. The two attachment parts 12 may also be dimensioned unequally.

(27) The embodiment of FIGS. 5c and 6c differs from the embodiment of FIGS. 5b and 6b in that the two attachment parts 12 do not lie precisely diametrically opposite one another, but rather are aligned to one another in an angle different from 180. This can be advantageous for the adapting of the exhaust pipe 11 to special installation situations.

(28) As explained, the attachment parts 12 can be arranged on the tubular body 15 exclusively for reinforcement purposes. This reinforcement proves to be particularly efficient when by means of the attachment part 12 said cavity 13 is created outside the tubular body 15 carrying exhaust gas, because thereby the area moment of inertia of the entire exhaust pipe 11 increases significantly. However, the embodiment is preferred in which the cavity 13 is used as a sound absorption chamber, so that an acoustic coupling exists between the interior 24 of the tubular body 15 and the cavity 13. For this, the cavity 13 must be tight with respect to an environment 32 of the exhaust pipe 11. As explained above with regard to FIG. 4, the closure elements 31 can be provided for this. These closure elements 31, however, are not illustrated in FIGS. 6a to 6d.

(29) According to the variant of FIGS. 5e and 6e, the exhaust pipe 11 or respectively the exhaust pipe tubular body 15 can extend in a curved manner, so that the tubular body 15 has a curve 33. The attachment part 12 is in this case preferably arranged on an inner side 34 of the curve 33 on the tubular body 15. Hereby, the curved pipe 11 can be reinforced particularly efficiently. In addition, the attachment part 12 according to FIGS. 5e and 6e can be respectively shaped in a targeted manner so that the cavity 13 at its longitudinal ends is closed respectively directly by the tubular body 15. This can be realized particularly simply when the attachment part 12 is configured as a shell body 19. Separate or additional closure elements 31 can therefore be dispensed with. As can be seen, in this side view the two legs 20 of the U-shaped shell body 19 then respectively have an edge remote from the straight curve 21 of the shell body 19, along which the weld seam 16 extends. This edge has here a curvature which corresponds to the curvature of the curve 33 of the tubular body 15, i.e. has substantially the same radius of curvature.

(30) While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.