acoustic zeuna

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Acoustic Development: Motorbike Muffler 31.09.02 ZS Motorrad-Team Detlev Rammoser +49 (0)821 4103 594 Conflict: Acoustic - Power - Design Initial Problem: - Pass by level: Tailpipe noise too loud - Subjective noise: Sound too aggressive - Pressure loss: Limit already reached - Design: Volume is fixed

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Page 1: Acoustic Zeuna

Acoustic Development: Motorbike Muffler

31.09.02ZS Motorrad-TeamDetlev Rammoser+49 (0)821 4103 594

Conflict: Acoustic - Power - Design

Initial Problem:

- Pass by level: Tailpipe noise too loud

- Subjective noise: Sound too aggressive

- Pressure loss: Limit already reached

- Design: Volume is fixed

Page 2: Acoustic Zeuna

Acoustic Development: Motorbike Muffler

31.09.02ZS Motorrad-TeamDetlev Rammoser+49 (0)821 4103 594

- Better damping of the specific frequencies

- Rapid evaluation of different principles with GT-Power(interference, volume distribution, resonators)

- Experimental validation

How this can be solved ?

Page 3: Acoustic Zeuna

31.09.02ZS Motorrad-TeamDetlev Rammoser+49 (0)821 4103 594

Basic system - resonances

U/min U/min

Acoustic Development: Motorbike Muffler

Page 4: Acoustic Zeuna

31.09.02ZS Motorrad-TeamDetlev Rammoser+49 (0)821 4103 594

Quick mesh generation with the muffler preprocessor (~1h)

Acoustic Development: Motorbike Muffler

Page 5: Acoustic Zeuna

31.09.02ZS Motorrad-TeamDetlev Rammoser+49 (0)821 4103 594

Basic muffler: principle layout

Acoustic Development: Motorbike Muffler

Page 6: Acoustic Zeuna

Transmissionloss 20 °C

-20

-10

0

10

20

30

40

50

60

0 100 200 300 400 500 600 700 800

Frequency [Hz]

TL

[d

B]

GTP Basis 20 °C

Exp. Basis 20 °C

31.09.02ZS Motorrad-TeamDetlev Rammoser+49 (0)821 4103 594

Model validation (basic muffler)

Acoustic Development: Motorbike Muffler

Page 7: Acoustic Zeuna

Transmissionloss 650 °C

-20

-10

0

10

20

30

40

50

60

0 100 200 300 400 500 600 700 800

Frequency [Hz]

TL

[d

B]

GTP Basis 20 °C

GTP Basis 650 °C

frequency shift f0

31.09.02ZS Motorrad-TeamDetlev Rammoser+49 (0)821 4103 594

Temperature influence: frequency shift

Acoustic Development: Motorbike Muffler

Page 8: Acoustic Zeuna

31.09.02ZS Motorrad-TeamDetlev Rammoser+49 (0)821 4103 594

Modified muffler

Acoustic Development: Motorbike Muffler

Page 9: Acoustic Zeuna

31.09.02ZS Motorrad-TeamDetlev Rammoser+49 (0)821 4103 594

Transmission loss of muffler variants

Basis with longer resonators

modified

Basis

Acoustic Development: Motorbike Muffler

Page 10: Acoustic Zeuna

31.09.02ZS Motorrad-TeamDetlev Rammoser+49 (0)821 4103 594

Modified system - highly reducedresonances

Acoustic Development: Motorbike Muffler

U/min U/min

Page 11: Acoustic Zeuna

Overall level [dB(A)]400 Hz

6th Order

600 Hz

8th Order

120 Hz

2nd Order 600 Hz

6th Order

31.09.02ZS Motorrad-TeamDetlev Rammoser+49 (0)821 4103 594

Basic system - order analysis

Acoustic Development: Motorbike Muffler

Page 12: Acoustic Zeuna

31.09.02ZS Motorrad-TeamDetlev Rammoser+49 (0)821 4103 594

Improvement of - 3 dB wrt. nearfield

- 3 dB

Overall level [dB(A)]

Acoustic Development: Motorbike Muffler

Page 13: Acoustic Zeuna

- 20 mbar

Basis with longer resonators

modifiedBasis

31.09.02ZS Motorrad-TeamDetlev Rammoser+49 (0)821 4103 594

Pressure loss analysis

Acoustic Development: Motorbike Muffler

Page 14: Acoustic Zeuna

31.09.02ZS Motorrad-TeamDetlev Rammoser+49 (0)821 4103 594

Conclusion

The technical solution:

- Elimination of the relevant frequencies by interference effects

- Quick evaluation of the variants with simple GT-Power models

- After 1st hardware loop promising results

Acoustic Development: Motorbike Muffler