Sundstrand Corporation

James V Rector

Malcolm J McArthur

Gary Lester Goldberg

Paul E Hilgeman

David E Jeorling

Mahendra P Desai

Charles H Dutart

In a power transmission or generation apparatus having a source of heated pressurized air, the problem of achieving rapid controlled engagement of a hydraulically actuated clutch at low ambient temperatures is solved by utilizing a portion of that heated pressurized air for heating only that small control volume of hydraulic fluid within a clutch control circuit needed to achieve rapid actuation and stable control of the hydraulic clutch. Our invention is thus particularly applicable in a power transmission or generation apparatus having a gas turbine engine, or a turbocharged piston engine as the prime mover. With gas turbine engine powered units, our invention contemplates the use of compressor discharge air, rather than exhaust products for heating the hydraulic fluid. Similarly, for piston engines our invention contemplates the use of turbocharger discharge air rather than exhaust products. In one embodiment a clutch and a control circuit are provided in which the fluid volume of the control circuit is minimized, and fluid removal features are provided to effectively drain all residual fluid from a portion of the control circuit following disengagement of the clutch. On subsequent start-up from cold ambient temperatures, the drained portion of the control circuit is filled with pre-heated fluid prior to engagement of the clutch thus eliminating problems of slow response and controllability encountered due to cold viscous fluid in prior clutch control circuits.

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San Diego, CA, United States of America

James V Rector