Dual stage fluid clutch motor with electric controls including time delay

A clutch control system for an automobile having an accelerator, a gear shift lever and a friction clutch including a driving element, a driven element and yieldable means for forcing said elements into contact with each other to effect an engagement of the clutch, the clutch control system comprising:

• clutch actuator means for operating said clutch including a pressure differential operated motor having a power element operably connected to one of said elements of said clutch and a vacuum chamber;
• a source of vacuum;
• a clutch control valve assembly including a control chamber, a clutch release valve for establishing an air flow communication between said vacuum chamber and said source of vacuum and cutting an air flow communication between said vacuum chamber and said control chamber when a solenoid thereof is energized and for cutting the air flow communication between said vacuum chamber and said source of vacuum and establishing the air flow communication between said vacuum chamber and said control chamber when said solenoid thereof is not energized, an air-on valve for establishing an air flow communication between said control chamber and the ambient atmosphere when a solenoid thereof is energized, and an accelerator actuated valve for establishing a restricted air flow communication between said control chamber and the ambient atmosphere in response to manipulation of said accelerator;
• and control circuit means for energizing said solenoids of said clutch control assembly, said control circuit means including a circuit portion including therein said solenoid of said clutch release valve, said circuit portion being effective to permit a current to pass through said solenoid of said clutch release valve upon gearshifting, said control circuit means including a second circuit portion including delay means for permitting current to pass through said solenoid of said air-on valve for a predetermined time after current passing through said solenoid of said clutch release valve has been cut, and a transistor electrically connected with said solenoid of said air-on valve means with its base connected with said delay means, whereby said solenoid of said air-on valve is simultaneously energized upon energization of said solenoid of said clutch release valve and said solenoid of said air-on valve is maintained energized for said predetermined time after said solenoid of said clutch release valve has been deenergized.