US 12,071,874 B2
Sound attenuating engine exhaust system
Steve E. Williams, Cherry Valley, CA (US); and Kevin McClelland, Riverside, CA (US)
Assigned to K&N Engineering, Inc., Riverside, CA (US)
Filed by K&N Engineering, Inc., Riverside, CA (US)
Filed on Jan. 22, 2021, as Appl. No. 17/156,364.
Claims priority of provisional application 62/965,732, filed on Jan. 24, 2020.
Prior Publication US 2021/0231035 A1, Jul. 29, 2021
Int. Cl. F01N 1/02 (2006.01); F01N 1/06 (2006.01); G10K 11/16 (2006.01); G10K 11/172 (2006.01); G10K 11/175 (2006.01)
CPC F01N 1/023 (2013.01) [F01N 1/06 (2013.01); G10K 11/161 (2013.01); G10K 11/172 (2013.01); G10K 11/175 (2013.01); F01N 2490/15 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A sound attenuating engine exhaust system to convey exhaust gases away from an internal combustion engine of a vehicle, the exhaust system comprising:
an exhaust inlet configured to receive exhaust gases from the internal combustion engine;
a first resonator coupled with the exhaust inlet and configured to dampen at least one frequency of exhaust sound waves, the first resonator comprising a drain hole configured to allow moisture from the exhaust system;
an exhaust outlet for directing the exhaust gases out of the first resonator;
a second resonator configured to cooperate with the first resonator to dampen one or more frequencies of exhaust sound waves;
a resonant neck connecting the second resonator with the exhaust outlet and configured to cooperate with the second resonator to dampen the one or more frequencies of exhaust sound waves, wherein the resonant neck is disposed between an exhaust tip and the first resonator wherein the second resonator includes an exterior guide tube having a first length disposed between a first endcap and a second endcap; and wherein the resonant neck includes a first guide tube having a second length that extends from the first endcap into an interior of the exterior guide tube wherein the first length and the second length are tuned with respect to one another so as to dampen the one or more frequencies of exhaust sound waves by way of destructive interference and Helmholtz resonance; and
wherein an incident sound wave is encountered entering the resonant neck when a reflected sound wave arrives at the beginning of the resonant neck.