Patent ID: 8224544

Claim:
Method to launch a vehicle including a powertrain comprising an internal combustion engine and first and second electrical machines and an electro-mechanical transmission selectively operative to transmit torque to a driveline, comprising: operating the electro-mechanical transmission in a continuously variable mode to transmit motive torque from a first electrical machine to the driveline, the first electrical machine mechanically independent and decoupled from the internal combustion engine and the internal combustion engine mechanically independent and decoupled from the driveline when a clutch is selectively released; selectively increasing an operating speed of the internal combustion engine independently from the driveline speed when an operator torque request exceeds a predetermined threshold, the increased operating speed of the internal combustion engine providing increased power input to the second electrical machine to generate electrical energy transmitted to the first electrical machine to facilitate increased motive torque from the first electrical machine to the driveline and pressurizing the clutch for a subsequent actuation; and subsequent to selectively increasing the operating speed of the internal combustion engine and pressurizing the clutch, partially actuating the clutch providing partial coupling of the second electrical machine and the internal combustion engine to the driveline to transmit motive torque generated by the second electrical machine and the internal combustion engine to the driveline through a controlled clutch torque wherein the clutch is slipping, the clutch slippage increasing the driveline speed towards the increased engine operating speed to meet the operator torque request.