Engine noise reducer

摘要

A noise reducer for an engine induction system comprises an outer duct having an inlet and outlet, and an inner duct having an inlet and outlet. The inner duct has a contained portion including the inner duct outlet and a portion of the inner duct adjacent to the inner duct outlet. The contained portion is contained in the outer duct with the inner duct outlet being adjacent the outer duct outlet. The noise reducer further comprises a closure extending away from the inner duct into engagement with the outer duct. The closure is spaced apart from the inner duct outlet along the axis of the inner duct. A resonance chamber is defined by the space between the contained portion, closure and outer duct. A chamber port is defined by the space between the inner duct outlet and the outer duct. The outer duct outlet is connectable to an upstream end of the induction system so that air flows through the inner duct prior to entering the induction system and the resonance chamber communicates with the induction system enabling sound waves from the induction system to enter and exit the resonance chamber through the chamber port. The resonance chamber has a cross section and length sized so that sound waves exiting said resonance chamber destructively interfere with sound waves in the induction system to reduce noise produced by the induction system.