Page 762 - Automotive Engineering Powertrain Chassis System and Vehicle Body

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Exterior noise: Assessment and control C HAPTER 22.1

Intake filter box with 300-mm sidebranch on a parallel-pipe snorkel
60
With sidebranch

Without sidebranch
50
40
Attenuation (dB) 30

–10
0 100 200 300 400 500 600 700 800 900 1000
Frequency (Hz)

Fig. 22.1-37 The effect of adding a sidebranch resonator calculated using APINEX software.

compliant to give adequate vibration isolation. In terms
of vehicle reﬁnement, interior noise concerns should
generally inﬂuence the mounting of the ﬁlter box.

22.1.3.14 Exhaust noise control
The earlier discussion of intake system design applies
equally to the exhaust system with the following notable
exceptions:
Fig. 22.1-38 Photograph of a production snorkel with sidebranch The inﬂuence of the ﬂow is much greater in the
mounted.
exhaust system due to the higher ﬂow speeds.

Intake filter box with simplified model of manifold and zip tube
90
With manifold and zip tube
80 Filter box only
70
60
Attenuation (dB) 50
40

30
20
10
0

–10
0 100 200 300 400 500 600 700 800 900 1000
Frequency (Hz)
Fig. 22.1-39 The inﬂuence of the intake manifold and zip tube calculated using APINEX software.

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