Abstract: An air intake apparatus for use in a spark-assisted diesel engine having a throttle valve mounted in an air intake connector connected with an air intake system of the engine, and a throttle valve actuating mechanism connected with a fuel regulating mechanism of the engine so that the throttle valve may be actuated or turned in the direction of throttling when the engine is operating at a partial load condition. The throttle valve actuating mechanism is connected through a mechanical device or the combination of the mechanical device and an electric device with the fuel regulating mechanism of the engine.