Patent ID: 8256571
Filing Date: 2012-09-04
Classification: F01N

Abstract:
1. A muffler for raising an audible pitch of an internal combustion engine's exhaust note, comprising: an enclosed case having an inlet and an outlet; and a plurality of flow-directing components adapted to subdivide an inlet flow into a plurality of interior flows comprising: a flowtube extending between the inlet and the outlet to form a first substantially-direct interior flow passage providing the shortest flow length through the enclosed case between the inlet and the outlet; and at least two deflector plates spanning a distance between a top and a bottom of the enclosed case and oriented transverse to a longitudinal center axis of the case, and supporting the flowtube therethrough, wherein adjacent deflector plates are laterally offset from a longitudinal center axis in opposite directions with wide gaps between each deflector plate and alternating far sidewalls forming a tortuous passage providing a second interior flow passage between the inlet and the outlet and having a flow length at least about twice the flow length of the first interior flow passage, and wherein narrow gaps between each deflector plate and alternating near sidewalls form by-pass shortcut flow passages to provide at least one intermediate interior flow passage which splits off from the second interior flow passage between the inlet and the outlet, and wherein at least one of the at least one intermediate flow passage recombines with the second interior flow passage between the inlet and the outlet.