Patent ID: 7556123
Filing Date: 2009-07-07
Classification: F01N,F02M,G10K

Abstract:
1. A muffler duct comprising: a duct body of a generally cylindrical shape having an inside and outside defined by a circumferential wall; and a resonance box of a box shape having an inside and outside defined by a partition wall and mounted on said duct body, wherein a gas vent opening portion including a gas vent opening having a through hole shape and a gas-permeable member having a gas vent passage of a labyrinth shape for covering said gas vent opening is formed in said partition wall; wherein said resonance box houses a portion of said duct body therein; wherein said circumferential wall has a communication opening of a through hole opened in said resonance box, and wherein the communication opening is open and unobstructed; wherein the inside of said duct body and the inside of said resonance box communicate directly with each other through said communication opening; and wherein said gas vent opening portion is formed in said partition wall at a position to confront said communication opening.