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US 4,501,341 AGranted
Low frequency muffler
OwnerAdrian D. Jonesinventor
Life of this patent
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Abstract
A muffler comprises two Helmholtz resonators, one tuned for high frequency and the other for low frequency. There is a resonance of the high frequency resonator volume's compliance and the effective tail pipe gas inertance which produces an undesirable low frequency noise. This is matched by the resonant frequency of the low frequency resonator, and suppressed thereby. A secondary effect to suppress noise at frequencies above said low frequency resonance due to the tailpipe gas inertance increasing linearly with frequency.
Claims6
A muffler comprising
- a first and a second Helmholtz resonator, the first having a relative volume compliance and relatively high resonance frequency and the second having a relatively low resonance frequency;
- a main exhaust pipe and a tail pipe having a relative acoustical instance, the mean exhaust pipe being in gas flow communication with each said resonator, and in gas flow communication with said tail pipe,
- and wherein the acoustical inertance of the tail pipe and the compliance of the high resonance frequency resonator being such that said low resonance frequency substantially matches the resonance of the combination of said high resonance frequency resonator volume's compliance and said tail pipe acoustical inertance.
Dependencies are inferred from the claim text.