IGNITION TIMING CONTROL SYSTEM

摘要

Spark timing control apparatus for an internal combustion engine having a throttle controlled intake passage for an air-fuel mixture. A vehicle is powered by the engine. A vacuum line from the intake passage downstream from the throttle valve is connected to a three-way valve which, in turn, has one conduit connected to a spark advance chamber and another conduit connected to a spark retard chamber. Another valve closes the vacuum line when the engine temperature is low. An electrical switch sensitive to velocity of the vehicle actuates the three-way valve electromagnetically to connect the vacuum line to either of said chambers for actuating a movable member which controls the ignition timing of the engine. The conduit leading to the spark retard chamber also leads to a vacuum chamber in an additional fuel supply system having a valve, so that when the spark is retarded the additional fuel supply is cut off.