Abstract: The state of a fluid coupling in a motor vehicle powertrain is selectively controlled during neutral idle operation of the engine for increasing the engine temperature to a desired level. The fluid coupling includes an input member connected to the engine and an output member connected to the transmission, and the output member is selectively grounded under specified enable conditions to impose an engine load for raising the engine operating temperature. The output member is released to resume normal operation of the powertrain when the enable conditions are no longer met or an estimate of the fluid temperature in the coupling reaches or exceeds a predefined temperature.

Abstract: 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.

Abstract: A driver-initiated low traction control method limits the drive torque of a motor vehicle during operation on low traction road surfaces. The low traction control mode is initiated by actuation of a switch or by moving a transmission range selector to a Low range while the vehicle is substantially stopped, and terminated by further actuation of the switch or by returning the range selector back to the Drive setting. The low traction control mode limits the engine torque as required to limit the drive wheel torque and its rate of change, so long as cruise control is inactive, the accelerator pedal setting is less than a reference level, and the transmission is operating in a gear other than its top gear. When the low traction control mode is terminated, the engine torque limits are progressively removed in a way that does not produce perceptible acceleration or deceleration of the vehicle.

Abstract: A driver-initiated low traction control method limits the drive torque of a motor vehicle during operation on low traction road surfaces. The low traction control mode is initiated by actuation of a switch or by moving a transmission range selector to a Low range while the vehicle is substantially stopped, and terminated by further actuation of the switch or by returning the range selector back to the Drive setting. The low traction control mode limits the engine torque as required to limit the drive wheel torque and its rate of change, so long as cruise control is inactive, the accelerator pedal setting is less than a reference level, and the transmission is operating in a gear other than its top gear. When the low traction control mode is terminated, the engine torque limits are progressively removed in a way that does not produce perceptible acceleration or deceleration of the vehicle.