Patent ID: 9109511
Filing Date: 2015-08-18
Classification: F02C,Y02E,Y02T

Abstract:
1. An apparatus suitable for use in a compressed gas-based energy storage and recovery system, the apparatus comprising: a pneumatic cylinder having a working piston disposed therein for reciprocating movement in the pneumatic cylinder, the working piston dividing the pneumatic cylinder into, and defining therewith, a first pneumatic chamber and a second pneumatic chamber; a first hydraulic actuator coupled to the working piston to drive, or be driven by, the working piston, the first hydraulic actuator including a first hydraulic cylinder and a first hydraulic piston disposed for reciprocating movement in the first hydraulic cylinder, the first hydraulic piston dividing the first hydraulic cylinder into, and defining therewith, a first hydraulic chamber and a second hydraulic chamber; a second hydraulic actuator coupled to the working piston to drive, or be driven by, the working piston, the second hydraulic actuator including a second hydraulic cylinder and a second hydraulic piston disposed for reciprocating movement in the second hydraulic cylinder, the second hydraulic piston dividing the second hydraulic cylinder into, and defining therewith, a third hydraulic chamber and a fourth hydraulic chamber; and a hydraulic controller fluidically coupleable to the first hydraulic actuator and the second hydraulic actuator, the hydraulic controller operable to cause the first hydraulic actuator to displace the working piston in a first direction to compress gas contained in the first pneumatic chamber and in a second direction to compress gas contained in the second pneumatic chamber, the hydraulic controller operable to selectively provide or not provide pressurized hydraulic fluid to one or more of the first, second, third, and fourth hydraulic chambers in at least four combinations, each combination producing a different net actuator force on the working piston acting in the first direction, each combination having a different net hydraulic piston area,