Air atomizing throttle body

Claim 1

A central fuel injection type fuel feed system for an automotive type internal combustion engine including an air/fuel throttle body having an air/fuel 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 for discharge of fuel thereinto in a longitudinal direction with a conical-like spray pattern, and an axially movable sleeve type throttling valve for variably controlling the flow of air into the passage for mixture with the fuel sprayed therein, the valve and injector means together defining a variable area convergent-divergent air flow area between, the sleeve valve including a sleeve and annular air throttling means projecting radially inwardly of the sleeve and tapering progressively inwardly in an axial direction towards the intake manifold end of the throttle body, the fuel injection means including a cup-shaped member having an angled side wall portion cooperating with the throttling means to define the path varying in area as a function of the axial movement of the sleeve valve, the cup-shaped member including a plurality of circumferentially spaced air swirl slots directing the air radially inwardly towards the fuel injector means for mixture of the air with fuel discharged from the injector means for atomization thereof, the sleeve being formed with a second annular diffuser-like means contiguous to and downstream of the first mentioned ramplike means and diverging radially outwardly in an axial direction towards the intake manifold end of the passage, the junction between the ramp and diffuser-like means constituting a step providing a large pressure differential to the air flowing between the two.