fluidly connected to a space formed about the outlet end portion of the fuel injector 50 the housing 54 also has an inlet port and passage 64 which connects with the conduit means 56 as seen in fig1 conduit 56 in turn is operatively connected to a source of clean air such as from an air filter assembly not shown the inlet 64 extends into an interior space or chamber 66 having a valve seat forming member 68 an upper end the seat member 68 is positioned between the chamber 66 and outlet passageway 62 a valving member 70 normally blocks flow into the outlet 62 by engagement with the valve seat member 68 valve 70 is affixed to a movable shaft 72 which is capable of selective axial movement within the housing 54 specifically a reduced diameter upper end portion 74 of the shaft 72 extends through a bearing block means 76 and a lower end portion 78 of shaft 72 is attached to and guided by movements of a linear actuator assembly 80 a preferred form of the actuator 80 is an electric stepper type motor when input signals are applied to the stepper motor it responds by moving the shaft axially a pre designed amount per signal movement of the shaft downward positions the valve 70 away from the seat forming member 68 resultantly air is drawn from the inlet passage 64 into chamber 66 then through fitting 60 and next through conduit 58 and reaches the space about the fuel injector 50 more specifically air flows into the intake passage 34 at an outlet adjacent the outlet end portion of the fuel injector this produces a flow of air adjacent to the spray of fuel from the injector preferably the air is caused to enter the.