Patent ID: 9097342
Filing Date: 2015-08-04
Classification: F16H

Abstract:
1. A method for automatically limiting a torque on a driveline of a continuously variable hydro-mechanical transmission of a work machine having an engine, comprising steps of: sensing a pressure condition in a hydrostatic power unit of the transmission, and if the pressure is high, estimating the mechanical efficiency of the motor of the hydrostatic power unit by monitoring an operating mode to determine whether the operation of the hydrostatic power unit is in a generation mode or a regeneration mode, providing the pressure, and determining a motor speed thereof; providing an estimated torque output of the hydrostatic power unit based on the pressure, and if the pressure is high, including the mechanical efficiency of the motor in the estimated torque output; estimating a torque output of a planetary power unit of the transmission as a function of the estimated torque output of the hydrostatic power unit, a ratio of gears drivingly connecting the hydrostatic power unit to the planetary power unit, and ratios of the gears of the planetary power unit; estimating the torque on an output member of the driveline of the transmission as a function of the estimated torque output of the planetary power unit and ratios of gears drivingly connecting the planetary power unit to an output of the transmission; if the estimated torque on the output member is greater than a predetermined value, then changing an operating parameter of the transmission to reduce the torque on the output member without reducing speed unless the speed is greater than a second predetermined value, and if the speed is greater than the second predetermined value, then reducing speed without reducing power to other systems run by the engine.