Powertrain Control of the Torotrak Infinitely Variable Transmission

The IVT control system can be viewed as having two distinct roles, namely that of steady state and transient torque management. Steady state management functions consist of setting engine power and transmission reaction torque to achieve optimal fuel economy, emissions and driver demanded wheel torque. The transient torque management function defines additional engine and transmission reaction torques, based on known inertia and plant responses, to manage the transition between these steady state operating points according to the driver's wishes, subject to plant constraints.

This paper gives a basic overview of the IVT steady state control functions, leading onto a detailed description of the transient torque management function. The software functions are illustrated in block diagram format, using simulation verification data plots and vehicle data logs for validation purposes.