Patent ID: 8376906

Claim:
An automatic transmission for a hybrid vehicle having a power plant including an internal combustion engine and an electric motor, said transmission comprising: a hydraulic circuit ( 110 ) having a source of pressurized fluid ( 112 ), said hydraulic circuit including an actuation circuit ( 114 ) that delivers pressurized fluid used to actuate components of said transmission and a cooling circuit ( 116 ) that delivers pressurized fluid used to cool components of said transmission; said source of pressurized fluid ( 112 ) including a first pump ( 134 ) operatively driven by the internal combustion engine of the hybrid vehicle and a second pump ( 136 ) operatively driven by the electric motor ( 138 ), a pair of check valves ( 152 , 154 ) disposed in series and in fluid communication with said second pump ( 136 ); said first pump ( 134 ) operable to supply pressurized fluid to said actuator circuit ( 114 ) and said cooling circuit ( 116 ) when operatively driven by the internal combustion engine; and said second pump ( 136 ) acting to supply pressurized fluid to said cooling circuit ( 116 ) when said first pump ( 134 ) is operatively driven by said internal combustion engine under certain predetermined conditions and said first check valve ( 152 ) is open and further acting to supply pressurized fluid to said actuation circuit ( 114 ) and said cooling circuit when said internal combustion engine is no longer operatively driving said first pump ( 134 ) and said first and second check valves ( 152 , 154 ) are open.