Abstract: A transmission utilizes an output torque sensor that relies upon magnetization of a section of the output shaft. The sensor produces an electrical current that varies as the torque transmitted by the shaft varies. However, the relationship between output torque and electrical current is impacted by part-to-part variability of the shaft and of the sensor. Conventional methods of compensating for this variability are hampered because the sensors and shafts are not paired until they are assembled into the transmission. A portable test may be used to characterize each shaft and each sensor. This characterization data includes average zero torque current and variability of zero torque current with respect to shaft position. A mapping is selected based on the shaft characterization and the sensor characterization and programmed into the controller.

Abstract: A method of operating a transmission includes measuring an output torque, estimating a gearbox input torque using a model, and estimating gearbox component torques based on a detailed gearbox model. The model used to estimate the input torque varies depending on whether a torque converter is locked, open, or slipping. In some operating conditions, multiple estimates are available for gearbox input torque, impeller torque, or shift element torque in which case the models are adapted. When an estimated component torque is outside an expected range, a warning flag is raised and diagnostic data is saved. When an estimated torque approaches or exceeds a torque limit, the input torque command may be reduced to prevent component damage. A warning flag may also be raised and diagnostic data saved in response to a model parameter being adapted to a value outside of a predetermined range.

Abstract: A method of operating a transmission includes measuring an output torque, estimating a gearbox input torque using a model, and estimating gearbox component torques based on a detailed gearbox model. The model used to estimate the input torque varies depending on whether a torque converter is locked, open, or slipping. In some operating conditions, multiple estimates are available for gearbox input torque, impeller torque, or shift element torque in which case the models are adapted. When an estimated component torque is outside an expected range, a warning flag is raised and diagnostic data is saved. When an estimated torque approaches or exceeds a torque limit, the input torque command may be reduced to prevent component damage. A warning flag may also be raised and diagnostic data saved in response to a model parameter being adapted to a value outside of a predetermined range.