Two-set point pilot piston control valve

摘要

The subject invention provides a compressor assembly <Bold>(20)</Bold> for an air conditioning system for a vehicle. The compressor assembly <Bold>(20)</Bold> is of the variable displacement angle wobble plate <Bold>(38)</Bold> type, and includes a housing <Bold>(22)</Bold> that defines a suction cavity <Bold>(24),</Bold> a discharge cavity <Bold>(26),</Bold> and a crankcase <Bold>(28).</Bold> An electronic control valve <Bold>(42)</Bold> controls the flow of a fluid between the discharge cavity <Bold>(26)</Bold> and the crankcase <Bold>(28)</Bold> for pressurizing the crankcase <Bold>(28)</Bold> to de-stroke the compressor assembly <Bold>(20).</Bold> The control valve <Bold>(42)</Bold> includes a pressure sensing member <Bold>(48),</Bold> which is responsive to a suction pressure to open fluid communication between the discharge cavity <Bold>(26)</Bold> and the crankcase <Bold>(28)</Bold> when the suction pressure is below a pre-determined set-point. The control valve <Bold>(42)</Bold> also includes an actuator port <Bold>(62)</Bold> in fluid communication with the discharge cavity <Bold>(26)</Bold> for urging the member <Bold>(48)</Bold> into the activated position to open fluid communication between the discharge cavity <Bold>(26)</Bold> and the crankcase <Bold>(28)</Bold> when the suction pressure is above the pre-determined set-point.