Patent ID: 6138988
Filing Date: 2000-10-31
Classification: F02D,F05C,F16K

Abstract:
A butterfly valve (1, 21) for controlling the flow of a fluid, in particular the air flow rate entering an air distributor provided in a fuel injection device for an internal combustion engine, said valve comprising a housing (2, 22) made of a molded synthetic material, a conduit (3, 23) arranged in said housing for through fluid flow, a control shaft (5, 25) guided in the housing, a butterfly shutter (4, 24) located at right angles to the conduit and mounted on said control shaft, the butterfly shutter (4, 24) designed to move between a position in which the conduit is closed and the butterfly shutter is oriented substantially perpendicular to the conduit and a position in which the conduit is fully open and the butterfly shutter is oriented substantially parallel to said conduit, wherein the butterfly valve is comprised of a ring (6, 26) with an upstream end and a downstream end coaxial to the conduit (3, 23), the ring inserted between the housing (2, 22) and the butterfly shutter (4, 24), the ring provided with a transverse guide bore (17) designed to receive the shutter's control shaft (5, 25), and comprising an active inner surface (13, 33) forming a seat for said butterfly shutter (4, 24) in the shutter closed position, the ring (6, 26) made of a dimensionally stable preselected material, and the housing (2, 22) of a preselected material molded around said ring, said ring (6, 26) arranged to provide, when the shutter (4, 24) is closed, a set clearance between the ring (6, 26) active inner surface (13, 33) and the butterfly shutter (4, 24), said clearance permitting a minimum fluid flow rate which is time-constant regardless of variations in humidity or temperature.