Bi frequency tuning system comprising side branches

Abstract From the Canadian patent

An engine apparatus comprising an internal combustion engine having a cylinder with an exhaust port, an exhaust gas passageway system communicating with the exhaust port for providing a first compressive wave arriving at the exhaust port prior to closure thereof, and an exhaust gas side branch for providing a second compressive wave arriving at the exhaust port after the first compressive wave and prior to closure of the exhaust port, which side branch includes a valve member mounted within the side branch adjacent the entry end and selectively and alternatively movable between an open position wherein the valve member opens the entry end of the side branch, and a closed position wherein …