Compressor clutch with time delay control

Claim 2

Apparatus for reducing, during full throttle operation, the load placed on an automotive engine by an air-conditioner compressor which is driven by said engine through an electrically operable clutch having an operating winding which engages the clutch when energized, said apparatus comprising: a switch; a vacuum actuator responsive to relative pressure for operating said switch, said switch being opened when the manifold vacuum drops below a predetermined level; conduit means for connecting said vacuum actuator to the intake manifold of said engine; and an electronic delay circuit including an SCR in series with said winding and said switch and a unijunction transistor timing circuit for triggering said SCR into conduction a predetermined interval after said switch closes and applies a voltage across said SCR for de-energizing said winding when said switch opens thereby to reduce the secondary load on said engine during full throttle operation and for re-energizing said winding only after a predetermined delay following closing of said switch.

Claim 3

Apparatus for reducing, during full throttle operation, the load placed on an automotive engine by an air conditioner which is driven by said engine through an electrically operable clutch having an operating winding which engages the clutch when energized, said apparatus comprising: a snap-acting switch; means responsive to relative pressure for operating said switching means; conduit means for connecting said pressure responsive means to the intake manifold of said engine, the mechanical hysteResis inherent in the snap-acting switch causing the switch to open at a first value of manifold pressure and to close at a second, significantly different, value of manifold pressure; a triggerable semi-conductor current switching device of the type which, when triggered, latches into a conductive state; means for connecting said switch, said clutch winding and said semi-conductor switching device in series for connection to a d.c. power source; and electronic circuit means for triggering said semiconductor switching device into conduction after a predetermined delay following the application of the d.c. source voltage across said device, whereby said clutch is disengaged when the manifold vacuum drops below said first value thereby to reduce the secondary load on said engine during full throttle operation and is re-energized only after a predetermined delay following a subsequent increase in manifold vacuum above said second value.

Claim 4

Apparatus for reducing, during full throttle operation, the load placed on an automotive engine by an air conditioner which is driven by said engine through an electrically operable clutch having an operating winding which engages the clutch when energized, said apparatus comprising: a snap-acting switch; means responsive to relative pressure for operating said switching means; conduit means for connecting said pressure responsive means to the intake manifold of said engine, the mechanical hysteResis inherent in the snap-acting switch causing the switch to open at a first value of manifold pressure and to close at a second, significantly different, value of manifold pressure; a triggerable semi-conductor current switching device of the type which, when triggered, latches into a conductive state; means for connecting said switch, said clutch winding and said semi-conductor switching device in series for connection to a d.c. power source; and electronic circuit means for triggering said semiconductor switching device into conduction after a predetermined delay following the application of the d.c. source voltage across said device, whereby said clutch is disengaged when the manifold vacuum drops below said first value thereby to reduce the secondary load on said engine during full throttle operation and is re-energized only after a predetermined delay following a subsequent increase in manifold vacuum above said second value.