Patent ID: 7201142

Claim:
In a tumble control valve for an internal combustion engine, said valve including: a valve body having top and bottom internal surfaces together defining at least a segment of an internal cavity having a longitudinal axis; and a valve blade having top and bottom edges and pivotally movable through substantially about a 90° rotation between fully open and fully closed positions in said internal cavity, said fully closed position being defined by said blade lying substantially perpendicular to said longitudinal axis with said blade bottom edge lying in substantially sealed engagement with said bottom internal surface and with said blade top edge lying in spaced relation to said internal top surface and thereby defining a gap wherethrough air may flow and undergo tumble, said fully open position being defined by said blade lying substantially parallel to said longitudinal axis whereby air may flow between said blade and said top and bottom internal surfaces with no or at least reduced tumble compared to said fully close position, wherein the improvement comprises: at least a segment of said internal bottom surface and said blade bottom edge being cooperatively configured such that said substantially sealed engagement is maintained from said fully closed position through at least a segment of said 90° rotation as said blade pivots from said fully closed to said fully open position, wherein said internal top surface and said blade top edge are cooperatively configured to substantially maintain the size of said gap through at least a segment of said angular rotation as said blade pivots from said fully closed to said fully open position.