Valve assembly and method of machining.

摘要

Induction air flow to an internal combustion engine is controlled or measured by a butterfly valve member (18) which extends into undercut recesses (20, 22) on opposite sides of the valve bore (14). The valve member (18) rotates in excess of 90° between its minimum air flow position and its maximum air flow position and offers a relatively low normalized change in the flow area around the valve member.