Method and apparatus for synchronized PTO control in a motor vehicle powertrain

摘要

One or more friction devices of a transmission coupled to an engine through a fluid coupling are used during engine neutral idle operation to control the state of the fluid coupling for synchronous engagement and disengagement of a PTO input gear with a transmission-driven gear. The fluid coupling includes an input member connected to the engine and an output member connected to the input shaft of the transmission, and the transmission friction devices temporarily ground the output member without mechanically coupling the transmission input and output shafts under specified enable conditions. This maintains the transmission input shaft in a stationary condition while an actuator engages or disengages the PTO input gear with the transmission-driven gear. Following engagement or disengagement of the PTO input gear, the friction devices are released to resume normal operation of the fluid coupling.