DE20201612U1 - Exhaust manifold for internal combustion engines - Google Patents

Description

Patent attorneys Tergau & Pohl, Nuremberg &iacgr;&iacgr;·&iacgr;··!&iacgr; .* . &iacgr;&iacgr; .* Page &Iacgr;

2 Description

3 ■ ■ ■

4 Exhaust manifolds for combustion engines

6 .

7 The present invention relates to an exhaust manifold with the features of the

&bgr; Preamble of claim 1. Such exhaust manifolds consist of

9 The state of the art consists of an inner shell and a surrounding inner shell.

10 outer shell, whereby an air gap is left between the inner shell and the outer shell

11 is left free for the so-called air gap insulation of the inner shell against

12 of the outer shell. The disadvantage of these known exhaust manifolds is the high temperature differences between the inner shell and the outer shell, whereby

µ the thermal expansion coefficient of the austenitic inner shell is usually

is one and a half times as large as the corresponding thermal expansion coefficient

16 of the ferritic outer shell. To ensure that the usually 3 to 5

&igr;? mm large circumferential air gap between inner shell and outer shell at each

is place is preserved, the inner shell must be laboriously placed in the outer shell.

19 , for example with the help of expensive wire press rings. To compensate

20 Sliding seats must also be provided to accommodate expansion. The emergency

21 The difficulty of installing these sliding seats limits the design options

22 possibilities for the design of the exhaust manifold. The introduction of

23 of the sliding seats can lead to acoustic problems in the exhaust system.

24 Another problem is the high heat load on the inner shell of the 2s exhaust manifolds according to the state of the art. Because of this high heat load,

26 load are high temperature resistant materials for the production of the inner shell

27 are required, usually thin austenitic stainless steels. Overall, it is

28 Thus, in the case of air-gap-insulated exhaust manifolds according to the state of the art

29 is a complicated and expensive design. In addition, air-gap insulated

30 gas manifolds are increasingly criticized for their excessive structure-borne sound radiation.

31 lungs.

Patent Attorneys Tergau & Pohl, Nürriber| ij .1 | _f ·' ·! j ·' Page

&igr; Regarding design freedom and acoustic behaviour,

2 Cast manifolds are considered good. However, the disadvantage is their high

3 its weight and its high heat capacity.

5 Finally, single-walled constructions are also known, or double-walled

6 designs in which the outer shell is in contact with the inner parts over the entire surface

7 and inserted together into an inlet flange on the cylinder head in order to be welded from the inside. However, this is not possible due to manufacturing technology.

9 technically difficult. In addition, the durability of such solutions is problematic.

10 matic. In addition, with welds in the gas flow there is always the risk of

11 Damage to subsequent components due to loose welding residues.

13 Based on these problems, the invention is based on the object of

14 to further simplify the design of a two-shell exhaust manifold and to

15 to improve its operating performance or to adapt it to today’s requirements

16 to be adjusted.

18 This task is solved by the combination of features of claim 1 in

19 solved in an inventive way. The outer shell and the inner shell

20 standing exhaust manifold has at least one partial area in which

21 chem the outer shell and the inner shell lie flush against each other, as well as

22 at least one further sub-area which is designed such that between In-

23 an air gap is left between the inner shell and the outer shell.

25 Since the outer shell and inner shell are flush at least in part,

26 other, prevail on both the outer shell and the inner shell

27 similar component temperatures. The installation of sliding seats can be

28 between the inner shell and the outer shell in this area can be dispensed with, which

29 the exhaust manifold has been significantly simplified in terms of design. In addition, the

so areas in which the inner shell and the outer shell are flush with each other

When the operating temperature of the exhaust system is reached, they are effective

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Patent Attorneys Tergau & Pohl, Nuremberg · · ; · * · ; .· · J · .· Page

1 Surface elements for heat dissipation. In this way it is possible to

2 shell materials with lower high temperature strength. 3

4 The sections with air gap insulation between the outer shell and the inner shell

5 prevent unwanted high outer shell temperatures from occurring. This

6 Preventing high outer shell temperatures in turn results in high structural

7 Real strength of the outer shell in the areas with air gap insulation according to

β. Consequently, heat is only transferred from the inner shell to those areas

9 the outer shell, in which the inner shell on the outer shell

10 is flush. This way the heat is transferred from the inner shell to the

11 Outer shell equally adjustable.
12

13 Finally, it is possible to produce the inner shell and the outer shell by deep drawing

14, which allows for a high degree of design freedom.

15 . '

16 In addition, the aforementioned auxiliary bearings of the inner shell in the outer

17 outer shell can be dispensed with.

19 Claims 2 to 6 relate to constructive, partly inventive, developments

20 developments of the exhaust manifold according to claim 1 for the advantageous design

21 of the interface between the engine and the exhaust manifold. Claim 2 provides for this,

22 the outer shell and the inner shell are connected at the end with an inlet flange,

23 which in turn can be adapted to the engine block, preferably screwed on.

24 It is particularly advantageous to provide the pipe socket proposed in claim 5 in

25 to insert the input flange and to position it between the input

26 gear flange and the outer shell and the inner shell to be switched between.

27 This effectively prevents the hot exhaust gas from reaching the

28 flange directly, heating it up and damaging it through corrosion.

29 In addition, the exhaust manifold can be manufactured more easily with robots.

This means that it is possible to weld the outer shell in the

31 flange area with smoother transitions, i.e. larger radii,

32 while small radii can still be realized in the inner shell,

Patent Attorneys Tergau & Pohl, Nuremberg &idigr;&iacgr;.&iacgr;. , I I ,' . '. I .' Page

1 to ensure a streamlined exhaust gas flow. According to claim 3,

2 only the outer shell with the input flange, or according to claim 5 with the

3 pipe sockets, welded to the inlet flange. The outer shell is thus firmly attached to the

4 pipe sockets or indirectly attached to the inlet flange via the pipe socket.

5 In contrast, the inner shell in the final assembly state is only fixed with the aid of

6 of a sliding seat on the inlet flange or according to claim 5 on the pipe socket

7. This movable mounting of the inner shell allows a free

&bgr; Pushing the inner shell against the pipe socket or the inlet

9 flange to compensate for expansion movements of the inner shell. 10

11 Particularly advantageous is the joint arrangement proposed in claim 6.

12 Weld seam for pipe socket, inlet flange and outer shell. The weld

13 seam runs outside the exhaust gas flow on the outside of the

14 pipe socket. The fact that only one single

15 weld seams are required. The connection of the outer shell, pipe socket

16 and input flange by means of a weld increases the fatigue strength of the

17 exhaust manifold. The outer shell is thus, in a sense, bluntly connected to the rear

18 side of the inlet flange and therefore not inserted into the flange.

19 The inner shell is shortened at the ends compared to the outer shell. The inner

20 shell thus ends in front of the exhaust line side surface of the inlet flange

21 sches. Due to its movable mounting on the pipe socket, the inner

22 shell in the flange area. The pipe socket thus serves as a

23 exhaust gas routing and thus decouples the inlet flange itself from the exhaust gas flow.

24 On the other hand, the pipe socket is a mechanical guide for the inner shell.

25 The inner shell and pipe socket therefore form a floating bearing with

26. The inner shell is therefore in the area of the connecting flange of

27 largely decoupled from the outer shell, so that the thermal

28 Reduced load on outer shell, inlet flange and welded joint

29, which is particularly advantageous at the high exhaust temperatures of gasoline engines

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&igr; The manufacturing process proposed in claims 7 and 8 is advantageous

2 Half-shell construction for the outer shell and the inner shell. If outer

3 shell and inner shell are manufactured in separate tools, so they can be

4 be designed so that the inner shell in one or more areas

5 of the outer shell. In addition, a catalyst can be integrated into the exhaust manifold β through the offset inner shell.

&bgr; The manufacture of outer shell and

9 Inner shell made of the same material has the advantage that both have the same

to expansion coefficients. An approximately equal expansion is

11 of the inner shell and outer shell. It is particularly cost-effective

12 natural, both inner shell and outer shell made of a ferritic steel

13. By deliberately creating the heat transfer areas using μ of the sub-areas in which the outer shell and inner shell are flush with each other

15, significantly more heat is transferred via the external

16 shell than with conventional air-gap-insulated exhaust manifolds according to the state of the art. At low to medium exhaust gas temperatures

18 However, especially during the warm-up phase, only the preferably thin inner

19 inner shell is responsible for the heat absorption. This is especially the case at the beginning of the

20 Operation of the plant undesirable heat losses in the exhaust gas flow are

21 proposed construction is not higher than for a similar air gap insulated

22 manifolds.

24 From a thermal point of view, it is particularly advantageous - as shown in

25 claim 11 proposed - one or more sections of the exhaust manifold,

26 in which heat transfer takes place, i.e. inner shell and outer shell

27 are flush with each other, in such areas of the engine compartment,

28 through which the outside air, i.e. the engine cooling air flow, flows. On

29 In this way, the cooling of the inner shell takes place via these partial surfaces, so that

30 the cooling air flow required in the engine compartment removes excess exhaust heat

31 is discharged via the manifold wall. It is therefore essential that only at high

32 temperature load excess heat is dissipated.

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2 The invention is further described with reference to the following figures.

3 genes:

5 Fig. 1 a sectional side view of the exhaust manifold and

β Fig. 2 a plan view of the exhaust line side of the inlet flange,

7 in which the cut end sides (section Il - Il in

&bgr; Fig.1) of both the outer shell and the inner shell are fixed.

10 In Fig. 1, an input flange 2 extends in the vertical direction 1. In the input

11 gang flange 2 are provided with mounting holes 3 for the insertion of

12 mounting screws. These mounting screws are used to secure the input

13 flange 2 in the final assembly state is screwed to a μ engine block not shown in the figures.

16 A pipe socket 5 is inserted into a flange opening 4 in the inlet flange 2.

17 ben. This pipe socket 5 extends in the flow direction 6 which is perpendicular to the vertical direction 1. The pipe socket 5 closes with the inlet

19 flange 2 on the engine compartment side 7 of the input flange 2, while

20 the pipe socket 5 in the flow direction 6 from the engine compartment side 7 in flow

21 direction of flow 6 opposite exhaust line side 8 from the inlet flange 2

22 protrudes like a collar.

24 The end of an inner shell 9 as well as the end of an inner shell 9 are pushed onto the pipe socket 5.

25 also an outer shell 10 of the exhaust manifold. The outer shell 10 consists

26 consists of a lower outer half shell 10a and an upper outer half shell 10b.

27 The inner shell 9 consists analogously of a lower inner half shell 9a and

28 of an upper inner half shell 9b. The lower inner half shell 9a and the upper

29 Inner half shell 9b are, viewed in flow direction 6, on the exhaust gas flow

30 side 8 are brought together and connected well in front of the inlet flange 2. The section shown in Fig. 1 shows a portion of the exhaust manifold in which 32 inner shell 9 and outer shell 10 lie flush against one another throughout.

Patent Attorneys TergauÄ Pohl, Nuremberg· ···· · j · ,·*·· j ,·* Page

2 From Fig. 1 it is also apparent that both the inner shell 9 and

3 the outer shell 10 is also pushed onto the pipe socket 5 with its end sides.

4 are. With the help of a circumferential weld seam 11, both the input

5 flange 2 as well as the pipe socket 5 and the end of the outer shell 10 are firmly welded together. The inner shell 9, on the other hand, is only positively

7 is pushed onto the pipe socket 5 and between the inner casing of the outer

β shell 10 and the outer shell of the pipe socket 5 longitudinally displaceable in flow

9 direction of travel 6 movably mounted.

11 Fig. 2 shows the view according to arrow P in Fig. 1 onto the exhaust system side 8 of the

12 input flange 2. The inner shell 9 and the outer shell 10 as well as the pipe

13 nozzles 5 are shown in section, with the section running approximately in the line η H-II in Fig. 1. The viewing direction according to arrow P in Fig. 1 therefore runs in the flow direction 6.

&igr;/ Fig. 2 shows an input flange 2 with in the vertical direction 1 perpendicular

18 extending horizontally of several adjacent flange openings

19 4. Both the inner shell 9 and the outer shell 10 are in

20 half-shell construction, which can be seen from the reference numbers for the lower

21 outer half shell 10a and the upper outer half shell 10b each exemplary

22 is shown.

24 In Fig. 2, approximately halfway between the two flange openings 4 in horizontal

25 valley direction 12, a system area 14 is visible, in which the

26 Inner surface of the outer shell 10 flush with the outer surface of the inner shell 9

27. Viewed in the horizontal direction 12, next to this system area

28 area 14 areas formed with clear air gaps 13 between Au-

29 outer shell 10 and inner shell 9, more precisely between the inner surface of the

30 outer shell 10 and the outer surface of the inner shell 9. The functioning of the exhaust manifold according to the invention is - as already mentioned at the beginning - such that 32 over the contact areas 14, i.e. those partial areas in which the outer

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&igr; outer shell 10 is flush with the inner shell 9, a temperature exchange between

2 show outer shell 10 and inner shell 9, which in the embodiment both consist of

3 ferritic steel. In contrast, in the areas with

4 air gaps 13 provide thermal insulation between inner shell 9 and outer

5 bowl 10 realized.

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&bull; · « · List of reference symbols Inlet flange 1 Mounting hole 2 Flange opening 3 Pipe socket 4 Flow direction 5 Engine compartment side 6 Exhaust system side 7 Inner shell 8th lower inner half shell 9 upper inner half shell 9a Outer shell 9b lower outer half shell 10 upper outer half shell 10a Weld 10b Horizontal direction 11 Air gap 12 Investment area 13 14

Claims (11)

1. Exhaust manifold for an internal combustion engine with an outer shell ( 10 ) and an inner shell ( 9 ) arranged in the outer shell ( 10 ), characterized by - at least one partial area (= contact area 14 ) of the inner shell ( 9 ) which is flush with the outer shell ( 10 ) and - an air gap ( 13 ) between at least one further partial region of the inner shell ( 9 ) and the outer shell ( 10 ). 2. Exhaust manifold according to claim 1, characterized in that the outer shell ( 10 ) and the inner shell ( 9 ) are fixed at the end to an inlet flange ( 2 ) adaptable to the engine block. 3. Exhaust manifold according to claim 2, characterized in that the outer shell ( 10 ) is firmly connected, preferably welded, to the inlet flange ( 2 ) in the final assembly state. 4. Exhaust manifold according to claim 2 or 3, characterized in that the inner shell ( 9 ) is displaceably mounted on the inlet flange ( 2 ) by means of a sliding seat in the final assembly state. 5. Exhaust manifold according to one of claims 2 to 4, characterized by a pipe socket ( 5 ) interposed between the inlet flange ( 2 ) on the one hand and the outer shell ( 10 ) and the inner shell ( 9 ) on the other hand as a connecting part of the inlet flange ( 2 ). 6. Exhaust manifold according to claim 5, characterized in that the inlet flange ( 2 ), the pipe socket ( 5 ) and the outer shell ( 10 ) are welded together by means of a common weld seam ( 11 ). 7. Exhaust manifold according to one of claims 1 to 6, characterized in that the outer shell ( 10 ) is composed of two outer half shells ( 10 a, 10 b). 8. Exhaust manifold according to one of claims 1 to 7, characterized in that the inner shell ( 9 ) is composed of two inner half-shells ( 9a , 9b ). 9. Exhaust manifold according to one of claims 1 to 8, characterized in that the outer shell ( 10 ) and the inner shell ( 9 ) consist of the same material. 10. Exhaust manifold according to claim 9, characterized by a ferritic steel as material for the outer shell ( 10 ) and the inner shell ( 9 ). 11. Exhaust manifold according to one of claims 1 to 10, characterized in that at least one partial region (contact region 14 ) with an inner shell ( 9 ) lying flush with the outer shell ( 10 ) is arranged in the engine compartment of the vehicle in the cooling air flow of the internal combustion engine.