Patent ID: 8209097
Filing Date: 2012-06-26
Classification: B60K,B60L,B60W,F16H,Y02T

Abstract:
1. Method for operating an electro-mechanical transmission operative to transmit an output torque originating from an engine and first and second electric machines to an output member, the electric machines electrically-operatively connected to an energy storage system for electrical power flow therebetween, the method comprising: operating the electro-mechanical transmission in a fixed gear operating range state; determining a minimum power flow between the energy storage system and the first and second electric machines to meet an operator torque request based upon electrical power constraints and motor torque constraints comprising developing a mathematical formula representative of the power flow between the energy storage system and the first and second electric machines based upon clutch reaction torques, transmission speed ratios, and the motor torques from the first and second electric machines and the torque input from the engine, executing a partial derivative of the mathematical formula with respect to output torque to determine said minimum power flow, and equating said partial derivative to zero and solving for the output torque; controlling-a motor torque from the first electric machine based upon the minimum power flow; and controlling a motor torque from the second electric machine based upon the minimum power flow, a torque input from the engine and the motor torque from the first electric machine to meet the operator torque request in the fixed gear operating range state.