Hydraulic control for a park by wire system used in a multimode hybrid transmission

摘要

A servo valve for shifting a transmission between a park and out of park position includes a valve housing and a park servo. A first and second solenoid is disposed in the valve housing for transmitting a respective first or second signal to shift the transmission to the respective first or second state of operation. The park servo is fluidly connected to the transmission and is responsive to the first and second signals to shift the transmission to the respective positions. Fluid pressure within the valve housing moves a valve member therein to move a piston within the park servo to shift the transmission to the corresponding position. A third solenoid transmits a third signal in combination with the second signal to latch and hold the valve member in the corresponding position.