Vehicle transmission with an automatic clutch

Claim 1

In an automobile having an accelerator (36); a gear shift lever (19) and a friction clutch having a driving element (3), a driven element (4) and yieldable means (6) for forcing said elements into contact with each other to effect an engagement of the clutch, a clutch control system comprising: a clutch actuator means (11) for operating said clutch including a pressure differential operated motor having a power element (11e) operably connected to one of said elements of said clutch and a vacuum chamber (11d); a source of vacuum (26); a clutch control valve assembly including a control chamber (17c), a clutch release valve means (21) for establishing an air flow communication between said vacuum chamber and said source of vacuum when a solenoid thereof (21e) is energized and for establishing an air flow communication between said vacuum chamber and said control chamber when said solenoid thereof is not energized, and an air-on valve means (17) for establishing an unrestricted air flow communication between said control chamber and the ambient atmosphere when a solenoid thereof (17h) is energized; said clutch control valve assembly further including an accelerator actuated valve means (30) for establishing a restricted air flow communication between said control chamber and the ambient atmosphere, said accelerator actuated valve means opening an effective flow area thereof in response to depression degree of said accelerator above a predetermined level; and a control circuit means for energizing said solenoids of said clutch control valve assembly, said control circuit means including a relay (40) including a relay coil (40a) and a normally open relay switch connected in series with said solenoid (21e) of said clutch release valve means (21), said normally open relay switch being closed upon energization of said relay coil; a throttle position responsive switch means (39) connected in series with said relay coil, said throttle responsive switch means being closed when a throttle valve opening is smaller than a predetermined level and being open when the throttle valve opening is larger than the predetermined level thereof; a shift switch (42) connected in series with said throttle position responsive switch means, said shift switch being closed upon manipulation of said gear shift lever; a vehicle speed responsive switch (47c) connected in series with said throttle position responsive switch means, said vehicle speed responsive switch being closed when the vehicle speed is lower than a predetermined level and being open when the vehicle speed is higher than the predetermined level thereof; and an actuator condition responsive switch (44) connected in series with said solenoid (17h) of said air-on valve (17), said actuator condition responsive switch being normally open and closed when said elements (3,4) of said clutch are disengaged from each other.