DE9314441U1 - Exhaust silencer for diesel engines, especially of commercial vehicles - Google Patents

Description

Patent Attorneys Tergau & Pohl, Nuremberg Il . &Idigr;"::":·"·""· Page 1

Description

6 Exhaust silencers for diesel engines

7 especially commercial vehicles

a The invention relates to an exhaust silencer for diesel engines

io especially commercial vehicles.

12 As a result of technological advances, the use of energy

13 diesel oil in conjunction with the trend towards a reduction in its

&eegr; Sulphur content, the proportion of pollutants in the exhaust gas is declining. The proportion

15 of solids, namely soot particles, and their particle size are in

is average also decreased. Since the gaseous pollutant content

&igr;? remained largely the same, it has increased in percentage terms due to the decline in

18 Soot content increased.

20 By optimizing the engine combustion process in conjunction with

21 low-sulphur diesel fuel, the soot particle emissions from modern

yes vehicle diesel engines are declining. This will make it possible in the medium term to

23 the applicable pollutant limits are exceeded by only one unregulated or

24 a regulated exhaust gas catalyst of correspondingly smaller size.

26 The invention is based on the object of improving the exhaust sound insulation and the

27 compliance with the applicable pollutant limits required

28 Reducing pollutants in a simple way. This solution

29 is that the functional structure of the silencer includes a

The exhaust catalyst is integrated as a functional component for sound insulation.

32 Especially for commercial vehicles (trucks and buses), this solution has the

33 Another advantage is the small space requirement. In such commercial vehicles,

34 namely for the installation of the exhaust system comparatively even less

35 installation space than in passenger cars. In tractors with semi-trailers, there is notoriously little space for an exhaust system. In addition, 37 commercial vehicles are designed to cope with ever larger operating radii.

Patent Attorneys Tergau & Pohl, Nuremberg* &iacgr;&idigr;. JIJ J J J "*· Page 2

&igr; correspondingly large fuel tanks mean less and less space

2 for the exhaust system.

4 Claim 2 ensures a special effectiveness of the catalyst as

5 Functional part for sound absorption in the exhaust silencer.

7 Claims 3 and 4 are based on the design of the usable

&bgr; catalysts.

10 There are basically different structural design options

11 embodiments. In the embodiment according to claim 5, a

12 rapid heat supply to the catalyst. This results in a rapid

13 Starting up the catalyst. This design is particularly suitable for &kgr; a silencer located far away from the engine.

ie The embodiment according to claim 6, however, is particularly suitable for

17 engines with large displacements where the silencing problem is greater

is than in engines with small displacement. This design is especially suitable for a

The exhaust silencer is designed to be mounted close to the engine.

21 In both systems, in the interest of space-saving accommodation,

28 of the functional parts can be advantageous if the exhaust gas flow to the gas outlet pipe

23 inside the silencer housing by approximately 180° opposite to the

24 Gas inlet pipe is diverted. This allows the exhaust gases to be directed to the additional

25 Heating of the catalyst carrier or the catalyst by exposure to

26 can be used from outside.

28 Claims 8 or 9 provide a particularly space-saving and

2a regarding the use of exhaust heat for additional heating of the

This catalyst has been usefully designed. The usually

The circular cross-sectional shape of the housing and catalyst wall gives the

sä Passage cross section between the free catalyst outer wall and the

33 The inner wall of the housing has a crescent-shaped shape, which allows the exhaust gas to pass through

34 is sufficient and beneficial for good heat exchange.

36 Another design provides for the arrangement of the exhaust catalyst between

37 two silencer chambers, with the catalyst being a

38 chamber-connecting pipe section and the partition wall.

Patent Attorneys Tergau & Pohl, Nuremberg H „ j**jj**j .*%**" Page 3

2 An exhaust gas catalyst consisting of a ceramic carrier is suitable

3 for integration into the silencer using expansion mat or wire mesh in the

4 silencer housings stored.

e The subject matter of the invention is shown in the figures as an example.

7 show:

9 Rg. 1 a longitudinal section through an exhaust silencer with integrated

10 Catalyst, which is the first catalyst in the flow direction of the exhaust gas.

11 Attenuation element in the functional structure is,

Fig. 2 is a solution in which the catalyst is inverted

13 Flow direction of the exhaust gas in the functional structure downstream

η attenuator is,

15 Fig. 3 a modified embodiment of the solution according to Fig. 2,

Fig. 4 shows a cross section through the silencer housing according to the

&igr;? Line IV-IV in Fig. 3,

Fig. 5 is a longitudinal section analogous to Fig. 1-3, in which the catalyst

ig between two silencer chambers, with a

20 constant flow direction for the exhaust gases,

21 Fig.6 the embodiment of a silencer with integrated

22 Catalytic converter with smaller outer diameter,

23 Fig. 7 is a cross-section along the line VII-VII in Fig. 6.

25 Within the essentially cylindrical housing 1, the

26 its outline shape also essentially cylindrical exhaust catalyst 2

27. Its arrangement is such that it serves as a functional part for

28 the sound insulation is effective. The catalyst 2 is mounted on the wall part 3 of the

29 housing 1. The exhaust gases of the engine are fed to the catalyst 2 from the so gas inlet pipe 4 in the flow direction 5. While maintaining the si flow direction 5, the exhaust gases exit the catalyst 2. At the end

32 of the housing 1, the exhaust gases enter a pipe bend 6, preferably in

33 a perforated U-pipe bend. The pipe bend 6 and the attached

34 adjacent to its convex side, with absorption material 24 made of mineral fibre

35 lined chamber form the damping part 19. In the pipe bend 6

36 the exhaust gas flow is diverted by 180° in the opposite direction 8. In this

37 In the opposite direction 8 it is attached to the outer skin of the catalyst housing or the

38 catalyst 2 along the gas outlet pipe 9, which is connected to a parallel

Patent Attorneys Tergau & Pohl, Nuremberg* I'. _t J ·; ; · * "*l Page 4

&igr; Axis next to the gas inlet pipe 4 at one end of the

&zgr; silencer housing 1.

4 In the embodiment according to Fig. 2, the exhaust gas flows through the

5 Gas inlet pipe 4 is also initially parallel to the housing axis 10. It is

β initially on the jacket of the catalyst housing or catalyst 2 up to

7 the closed other end of the housing. The guide of the

β hot exhaust gas flow in the feedthrough direction 5 on the catalyst housing or

9 along the catalyst 2 promotes its rapid heating. On the other

!o At the end of the silencer housing 1, the still uncleaned exhaust gas flow

n a deflection of 180° in area 11 of the silencer chamber, which is analogous

12 Fig. 1 front side with a damping part designed as a sound absorber 19

13. The diverted exhaust gas flow is fed through the inlet nozzle 12

14 into the catalyst housing and in the opposite direction 8 parallel to the

The housing axis 10 is guided through the catalyst 2. The catalytic

The cleaned exhaust gas then flows to the outlet pipe 9 of the system. The

&igr;? catalytically purified exhaust gas leaves the catalyst chamber via a

is the outlet funnel and is discharged from the silencer via the outlet pipe 9

is removed. The outlet pipe 9 is inside the silencer in the

so area of the damping chamber 25 perforated. The damping chamber 25 is

si sound absorption material 24, namely inside with steel wool 30 and outside with

22 Absorbent material 31 made of mineral fibre. The relative position of

23 Inlet pipe 4 and outlet pipe 9 correspond in the embodiment according to

24 Fig. 2 of the according to Fig. 1.

26 In the embodiment according to Fig. 3, the catalyst 2 is directly

27 adjacent to the deflection area 11. The exhaust gas flow enters

28 directly from the deflection area 11 into the catalyst body 2. The

29 analogous to Fig. 2 designed and effective damping part 19 contains here

30 also has absorption material on the inside made of steel wool and on the outside made of si mineral fiber. It forms a gas-permeable, over the entire

32 Cross section of the housing 1 extending sound absorber 32.

34 In the embodiments according to Fig. 1 - 3, the exhaust gas flow is

35 Flow direction before or after the catalyst 2 through funnel-shaped

36 widened or constricted pipe sections, which

37 Compensate for the difference in diameter between the catalyst 2 and the gas inlet or outlet pipe 4,9; 17,18. In these areas, the

Patent Attorneys Tergau & Pohl, Nuremberg* It , I ;; · ·**· ***i Page

&igr; of a conical shell designed gas guide cross-section as continuous

2 Broadband reflection point.

4 In the embodiment according to Fig. 5, the exhaust gas catalyst 13 is between

5 the two silencer chambers 14 in the silencer housing 15

6. The catalyst 13 forms a the two chambers 14

7 connecting pipe section. In this embodiment, the monolithic β catalyst 13 divides the silencer housing 15 into the two chambers 14. α The monolithic catalyst 13 is designed as the silencer chamber

10 partition wall is sound-insulating. The catalyst 13 is

11 of this design using expansion mat or wire mesh 16 in the housing 15

12. The inlet pipe 17 is supported on the front side by a base 26

13 and stored in the perforated bulkhead 27. The inlet pipe &pgr; 17 is provided with a perforated field 28 for the gas entry into the damping chamber.

is provided. The exhaust gas flow enters the perforated bulkhead 27 into the

The chamber 14 in front of the catalyst 13, flows through it and finally flows into

&igr;? the chamber 14 behind the catalyst. The end area of the silencer is

is a wall resonator and is filled with mineral fiber-like absorption material

19 filled in. In this embodiment, the flow direction 5

20 between inlet pipe 17 and outlet pipe 18 parallel to the housing axis

23 Fig. 6 is a modified embodiment of a silencer with

24 integrated exhaust catalyst 13, whose outer diameter, however, is

25 compared to the embodiment according to Fig. 5 is significantly smaller than the

26 Diameter of the housing 15.

28 Fig. 7 shows a monolith arrangement in which no exhaust gas flow is

29 Resonator chamber 22 between the exhaust catalyst 13 and the housing so occurs. The resonator chamber 22 is coupled to 31 the system through openings 23 in the bulkhead 20 and acts as a Helmholtz resonator.

Patent Attorneys Tergau & Pohl, Nuremberg _# . .... . &idiagr;I'.,I , '»,: ·, Page

List of reference symbols

1. Housing

2. Catalyst

3. Wall section

4. Gas inlet pipe

5. Flow direction

6. Pipe bend

7. Swelling mat

8. Opposite direction

9. Gas outlet pipe

10. Housing axis

11. Area

12. Entrance support

13. Catalytic converter

14th Chamber

15. Housing

16. Swelling mat

17. Gas inlet pipe

18. Gas outlet pipe

19. Damping part

20. Bulkhead

21. Bulkhead

22. Resonator room

23. Openings

24. Absorption material

25. Damping chamber

26. Floor

27. Bulkhead

28. Hole field

29. Bulkhead

30. Steel wool

31. Mineral fiber

32. Sound absorbers

Claims (1)

Patent attorneys Tergau & Pohl, Nuremberg,··.; ^.. ^ ^.. Page 1 · &igr; 93886 Expectations &bgr; 1. Exhaust silencers for diesel engines, especially for commercial vehicles, 10 characterized by 11 that within the silencer housing (1,15) an exhaust gas catalyst la (2,13) is effective as a functional part for sound absorption. &eegr; 2. Silencer according to claim 1, is characterized by ie that the catalyst (2,13) in the range of 2/5 to 4/5 of the longitudinal extension &igr;? of the silencer housing (1) or in the silencer housing (1) is arranged along the measured exhaust gas path. 20 3. Silencer according to claim 1, 21 characterized by 22 that the catalyst carrier used for the catalyst (2) is 23 monolithic form. 25 4. Silencer according to at least one of the preceding claims, 28 characterized by 27 that the catalyst carrier is made of metal or ceramic in honeycomb form 28 is. so 5. Silencer according to one or more of the preceding claims, 31 characterized by 32 that the catalyst (2,13) is connected from the gas inlet pipe (4,17) to this 33 coupled to the first damping element of the exhaust gas path 34 overall functional structure. se 6. Silencer according to one of claims 1 to 4, 37 characterized by 38 that the catalyst (2,13) is a in the direction of the exhaust gas path (U.-93886) Patent attorneysTergau& Pohl, Nuremberg,··. ; _t ·· .. Page 2 &igr; downstream, coupled to the gas outlet pipe (9,18) &zgr; is the attenuator of the overall functional structure. 4 7. Silencer according to claim 5 or 6, 5 characterized by 6 that the exhaust gas flow in the gas outlet pipe (9) within the 7 silencer housing (1) by approximately 180° in the direction opposite to 8 of the gas inlet pipe (4) is diverted and that the exhaust gases flowing through a catalyst-free a gas pipe (9 or 4) are used to heat the io catalyst carrier or the catalyst (2) are guided along the latter. 12 8. Silencer according to claim 7, is characterized by &eegr; - that the housing (1) and the catalyst (2) essentially form a is cylindrical in shape or has a cylindrical shell shape, ie - that the catalyst cross-section is smaller than the housing cross-section and &eegr; - that the catalyst jacket is in contact with the inside of the housing at this 18 is attached. 20 9. Silencer according to claim 8, 21 characterized by 22 that the catalyst jacket is attached to the gas outlet pipe (9) or the 23 Gas inlet pipe (4) is attached to the inside of the housing on the opposite side 24 is. 26 10. Silencer according to one or more of the preceding claims, 2r characterized by 28 that the catalyst (13) covers the silencer housing (1,15) in at least 29 two silencer chambers (14) and in the functional structure of the silencer, the bulkhead dividing the housing (1,15) and a si forms a pipe section connecting both silencer chambers (14). 33 11. Silencer according to one or more of the preceding claims, 34 characterized by 35 a functional structure with integrated catalyst (2) in the reflection design. 38 12. Silencer according to one of claims 1 to 10, (U:93886) I . I J **f ··« Patent Attorneys Tergau & Pohl, Nuremberg,·*, ; ."..**, Page 3 &bull; ■ · < &igr; characterized by &zgr; a functional design with integrated catalyst (2) in mixed 3 Reflection-absorption construction. 5 13. Silencer according to one of claims 1 to 10, 6 characterized by 7 a functional structure with integrated catalyst (2) in β absorption design. 10 14. Silencer according to one or more of the preceding claims, 11 characterized by 12 - that the catalyst (13), with smaller cross-section than the is silencer housing (15) in bulkheads (20,21) on the housing (15) &eegr; is stored, 15 - that no exhaust gases pass through the gap (22) between The catalyst body (13) and silencer housing (15) flow and &pgr; - that openings (23) in a gas inlet-side bulkhead (20) is space (22) to the exhaust system in such a way that the ig space (22) as Helmholtz resonator, sound energy destructive 20 is effective. 22 15. Silencer according to one or more of the preceding claims, 23 characterized by 24 that the integrated catalyst (2,13) in monolith form by means of a swelling mat or 25 Wire mesh (7,16) is mounted in the silencer housing (1,15).