The determine shows the vacuum clutch system. This type of clutch makes use of the existing vacuum during the motor manifold to function the clutch. The vacuum clutch contains a reservoir, non-return valve, vacuum cylinder with piston, and solenoid valve.  But let us stay with the topic of cars these https://clutchplate00763.theideasblog.com/33506216/new-step-by-step-map-for-clutch-plate