A viscous fluid clutch comprising: - a clutch plate and a drive shaft , the clutch plate being fixedly driven by the drive shaft ; - a housing rotatably supported by the drive shaft , the housing surrounding the clutch plate , the housing comprising a work chamber defining a shear space for the viscous fluid between the housing and the clutch plate ; - a storage chamber for the viscous fluid, whereby the storage chamber is comprised in the clutch plate ; - a viscous fluid supply connection and a viscous fluid return connection connecting the storage chamber and the work chamber , whereby the viscous fluid return connection and the viscous fluid supply connection are comprised within the clutch plate ; - a first valve (109, 14 A-D) located in the supply connection, the first valve (109, 14 A-D) permitting to selectively increase the quantity of viscous fluid present in the work chamber ; characterized in that , the viscous fluid clutch is further comprising: - a second valve (110, 13 A-D) located in the supply connection and closing the supply passage when the drive shaft is at rest, the second valve (110, 13 A-D) being movable to an open position by a centrifuge force generated by rotation of the drive shaft exceeding a predetermined centrifuge force threshold; - a third valve located in the viscous fluid return connection , the third valve being a one-way valve selectively permitting the passage of viscous fluid from the work chamber to the storage chamber when the viscous fluid applies on the third valve a pressure which exceeds a predetermined viscous fluid pressure threshold; - a vent for venting gas from the storage chamber to the work chamber ; whereby an enclosure comprising the connected storage and work chambers is hermetic. - a clutch plate and a drive shaft , the clutch plate being fixedly driven by the drive shaft ; - a housing rotatably supported by the drive shaft , the housing surrounding the clutch plate , the housing comprising a work chamber defining a shear space for the viscous fluid between the housing and the clutch plate ; - a storage chamber for the viscous fluid, whereby the storage chamber is comprised in the clutch plate ; - a viscous fluid supply connection and a viscous fluid return connection connecting the storage chamber and the work chamber , whereby the viscous fluid return connection and the viscous fluid supply connection are comprised within the clutch plate ; - a first valve (109, 14 A-D) located in the supply connection, the first valve (109, 14 A-D) permitting to selectively increase the quantity of viscous fluid present in the work chamber ; - a second valve (110, 13 A-D) located in the supply connection and closing the supply passage when the drive shaft is at rest, the second valve (110, 13 A-D) being movable to an open position by a centrifuge force generated by rotation of the drive shaft exceeding a predetermined centrifuge force threshold; - a third valve located in the viscous fluid return connection , the third valve being a one-way valve selectively permitting the passage of viscous fluid from the work chamber to the storage chamber when the viscous fluid applies on the third valve a pressure which exceeds a predetermined viscous fluid pressure threshold; - a vent for venting gas from the storage chamber to the work chamber ; <EOS>