Internal combustion engine throttle valve assembly

Abstract From the Canadian patent

An automotive type internal combustion engine has throttle valves in each of the inlet manifold passages between the carburetor and engine cylinders, the throttle valves consisting of a venturi cooperating with a centrally movable plug together define a variable area convergent-divergent flow area for flow at sonic velocity to provide turbulent to the air/fuel mixture, which improves mixing and atomization of the fuel and therefore a more uniform mixture.