Techniques for utilizing a torque converter quadratic model to determine a maximum powertrain torque capability

A powertrain control method for a vehicle, the powertrain control method comprising:

• storing, by a memory associated with a control system of the vehicle, empirical operation data for a powertrain of the vehicle, the powertrain comprising a torque generating system including (i) at least one of an electric traction motor and (ii) an engine connectable in series at an input of a torque converter;
• determining, by the control system and based on the empirical operation data, maximum torques for the torque generating system at each of a plurality of breakpoints corresponding to different impeller speeds for the torque converter and different speeds of the torque generating system, wherein each breakpoint of the plurality of breakpoints corresponds to a change in a slope of the maximum torque for the torque generating system;
• identifying, by the control system and between two particular breakpoints, (i) a linear intersection point between the maximum torque for the torque generating system and the impeller speed for the torque converter and (ii) an intersection region between the two particular breakpoints;
• determining, by the control system, a quadratic polynomial representation of the impeller speed for the torque converter across the intersection region based on the empirical operation data for the torque converter;
• and
• utilizing, by the control system, the quadratic polynomial representation of the impeller speed for the torque converter across the intersection region to control the powertrain.