Air-fuel intake system for an internal combustion engine

Claim 1

In an intake system for an internal combustion engine of the type comprising an intake pipe, fuel supply means for charging a fuel into said intake pipe so as to form an air-fuel mixture, an intake manifold for distributing the air-fuel mixture into cylinders of said engine, and a throttling system incorporated in said intake pipe between said fuel supply means and said intake manifold for controlling the flow rate of the air-fuel mixture to be delivered to said intake manifold, the improvement wherein said throttling system comprises: a stationary valve body having a surface spaced downstream from said fuel supply means by a predetermined constant distance in opposed relationship therewith and on which the charged fuel impinges, said stationary body being substantially in the form of a disc, a plurality of rods suspensing said stationary valve body from said intake pipe, and a movable tubular valve body having an outer wall surface, a part of whic is slidably closely engaged with an inner wall surface of said intake pipe downstream of said stationary valve body, and an inner wall surface which cooperates with at least a portion of the peripheral edge of said stationary valve body to define a valve opening in said intake pipe between said inner wall surface of said movable valve body and said portion of said peripheral edge, said inner wall surface of said movable tubular valve body being formed with recess means which cooperates with only a portion of the peripheral edge of said stationary valve body to define said valve opening until the opening area of said valve opening reaches a predetermined value, the valve opening being defined between the entire peripheral edge of said stationary valve body and the entire periphery of said inner wall surface of said movable tubular valve body when the opening area of said valve opening exceeds said predetermined value, said movable tubular valve body being movable relative to said stationary valve body in an axial direction of the former to vary the opening area of said valve opening, thereby controlling the air-fuel mixture charged into the cylinders of said engine.