Internal combustion engine

Claim 1

In an internal combustion engine, having a fuel mixture intake passageway, a throttle valve rotatably mounted across said passageway and movable from a closed engine idling position to a widely opened position, and defining an atmospheric side on one side thereof, and a vacuum side on an opposite side thereof, a throttle valve control means including therein a first diaphragm means defining a throttle control vacuum chamber on one side of the latter, said first diaphragm means being operatively connected to said throttle valve for rotating said throttle valve to a slightly opened position thereof in response to an intake vacuum pressure in said throttle control vacuum chamber, a first conduit selectively connecting said vacuum chamber of said throttle valve control means to said intake passageway at a point downstream of said throttle valve, vacuum control valve means operable in response to the intake vacuum pressure in said intake passageway for selectively communicating said first conduit with said intake passageway and with the atmosphere, respectively, and a distributor comprising a breaker plate and a vacuum servo means operatively connected to each other, said vacuum servo means including therein a second diaphragm means defining first and second vacuum chambers on opposite sides of the latter, respectively, said second diaphragm means being operatively connected to said braker plate for biasing said braker plate toward a spark timing advance position in response to vacuum pressure in said first vacuum chamber and for biasing said braker plate toward a spark timing retarded position in response to vacuum pressure in said second vacuum chamber, respectively, the improvement comprising: a first solenoid valve means and a second solenoid valve means for being actuated in dependency on engine speed, respectively, a second conduit connecting said first vacuum chamber of said vacuum servo means to said first solenoid valve means, a third conduit connecting said first solenoid valve means to said intake passageway at a position adjacent said throttle valve such that said third conduit communicates with the atmosphere side of said throttle valve when the throttle valve is closed in idle position and communicates with said intake passageway at the vacuum side of said throttle valve when the throttle valve is slightly opened, respectively, said first solenoid valve means communicating said first vacuum chamber in said vacuum servo means with atmosphere when engine speed is lower than a predetermined reference engine speed, and for communicating said first vacuum chamber with said intake passageway via said third conduit when the engine speed is higher than the predetermined speed, respectively, a fourth conduit connecting said second vacuum chamber of said vacuum servo means to said second solenoid valve means, a fifth conduit connecting said second solenoid valve means to said intake passageway at another position adjacent said throttle valve such that said fifth conduit communicates with the vacuum side of said throttle valve when the throttle valve is closed in idle position and communicates with the atmospheric side of said throttle valve when the throttle valve is slightly opened, respectively, and a sixth conduit connecting said second solenoid valve means to said first conduit, said second solenoid valve means communicating said second vacuum chamber in said vacuum servo means with said fifth conduit when the engine speed is lower than the predetermined speed, and for communicating said second vacuum chamber with said sixth conduit when the engine speed is higher than the predetermined speed, respectively.