Throttle body with slidable throttling valve

A central fuel injection type fuel feed system for an automotive type internal combustion engine including an air/fuel throttling body having wall means defining an air/fuel induction passage therethrough open at one end to air essentially at an atmospheric pressure level and adapted to be connected at its opposite end to the intake manifold of the engine to subject the passage to the varying vacuum levels therein, a fuel injector means concentrically positioned in the passage near the inlet thereto for discharge of fuel axially into the passage with a conical-like spray pattern, and an air/fuel throttling valve means in the passage for controlling the flow of air and fuel to the intake manifold, the valve means including an interengaging arrangement of an axially moveable dome-like valve member with an annular washer-like valve seat having a central opening, the arrangement defining a controlled air/fuel flow path between the member and valve seat varying in area as a function of the axial separation of the two, and aperture means in the dome-like member communicating the air to opposite sides of the member to essentially balance the pressure on opposite sides thereof, thereby reducing the force necessary to move the member axially, the passage of fuel through the controlled path effecting a shearing action of the fuel for atomizing the fuel.