Internal combustion engine system for exhaust emissions control utilizing an acoustic catalytic muffler

Claim 1

In combination, an internal combustion engine having a cylinder, means for reducing the amount of pollutants including residual combustibles among the exhaust emissions from said cylinder comprising an exhaust system leading from an exhaust port of said cylinder, means for providing air in at least stoichiometric ratio adjacent and downstream of said exhaust port for combustion of said residual combustibles among said exhaust emissions in said exhaust system, means for controlling the back pressure in said exhaust system comprising valve means positioned therein downstream from said exhaust port functioning to restrict mass flow at the lower engine speeds above idle thereby to maintain a back pressure higher than the normal back pressure of said exhaust system without said valve means and opening at the higher speeds and mass flow rates when said normal back pressure without said valve means is above the imposed back pressure, and the improvement comprising an acoustic catalytic muffler construction located upstream and adjacent said valve means, said acoustic catalytic muffler construction comprising a casing having an inlet and an outlet and an annular mass of material within said casing, said mass of material supporting a catalyst compound for reducing the amount of pollutants among said exhaust emissions from said cylinder, said inlet of said catalytic muffler construction and said outlet thereof each having a diameter substantially equal to the inner diameter of said annular mass of material and all being located for throughflow of said exhaust emissions through said muffler construction, said annular mass of material being comprised of a plurality of fibrous sections having a general helical configuration, adjoining sections having contrasting helix angles.