Abstract: An engine comprising a spark plug and a fuel injector in a combustion chamber and a temperature sensor used to judge if the gas temperature in the combustion chamber is a temperature at which self-ignition occurs when a spark is generated. Based on this judgement, a valve timing device is used to control the opening timing of the intake valve and maintain the gas temperature at a temperature at which self-ignition occurs when a spark is generated.

Abstract: A fuel injector comprising a needle valve and a stop member cooperating with the needle valve. The stop member selectively controls the maximum amount of lift of the needle valve to provide a smaller maximum lift or a larger maximum lift thereof whereby, when the required amount of fuel to be injected by the fuel injector is small, the needle valve is lifted to the smaller maximum lift, and when the required amount of fuel is large, the needle valve is lifted to the larger maximum lift.

Abstract: A two-stroke engine including a pair of intake valves which are symmetrically arranged with respect to a symmetrical plane including the axis of the cylinder. A masking wall is provided for each intake valve to mask the valve opening between the valve seat and the peripheral portion of the intake valve, which is located on the exhaust valve side, for the entire time for which the intake valve is open. These masking walls are also symmetrically arranged with respect to the symmetrical plane.

Abstract: Disclosed is a device for promoting the purification of exhaust gas in an internal combustion engine at the time of warm-up. The opening degree of the throttle valve of the carburetor is temporarily maintained open at about 20 degrees immediately after the engine is started. After this, the throttle valve is closed stepwise to its idling position as the temperature of the engine is increased. When the gear shift of the transmission is shifted from neutral to, for example, low gear, for driving a vehicle in the case wherein the opening degree of the throttle valve is being held open at about 20 degrees, the throttle valve is automatically closed to an opening degree which is smaller than 20 degrees.

Abstract: A dynamic pressure gas bearing device adapted to provide a floating support for a shaft rotating at a high speed and comprising a plurality of bearing pads each carried on a pivot and encircling the shaft. Each bearing pad comprises a relatively thin bearing shell having a part-cylindrical shape and a curved inner surface encircling the shaft and substantially complementary to the peripheral surface thereof, and a member made of an elastic material and associated with the bearing shell to substantially enclose the outer surface of the bearing shell and hold the bearing shell resiliently against the pivot.