Abstract: IVT delivers unique off road functionality for hybrid electric vehicle

IVT delivers unique off road functionality for hybrid electric vehicle

Michael Durack, Technology Director & Managing Director, Ultimate Transmissions

  • What do consumers want in off road functionality.
  • High wheel torque at low speed using very low power.
  • Full off road functionality under electric power only.
  • Reconfiguring conventional foot throttle for off road speed control.

An IVT transmission has the unique ability to deliver forward and reverse functions without disconnecting the engine from the wheels.  It creates very low speeds and high wheel torques within a transmission that is highly compact, lightweight and low cost.  It is ideal for application to vehicles with off-road functionality and can be combined with PHEV and MHEV strategies looking for fuel efficiency.

An IVT transmission using a toroidal traction CVT arranged in East West configuration, with 4WD functionality is presented.

A generic SUV fitted with this driveline is modeled using Simulink.  The vehicle is powered by a 3 litre V6 gasoline engine delivering 200kW of power and 320Nm of torque and a 50kW electric motor and controller delivering 200Nm of torque.  This vehicle has a number of operational modes including an off road mode designed to deliver very high wheel torques and low vehicle speeds.

An innovative control concept is proposed, when in off road mode, that converts the accelerator from a throttle to a speed controller delivering vehicle speeds of -1kph to 30kph. over the normal angular range of the accelerator pedal.  The driver has access to a form of low speed cruise control using his right foot as both a brake and a throttle.

A number of off-road maneuvers are modeled including those operating on electric power only.

The IVT can be seen as offering a number of advantages to the off-road market while reducing cost and incorporating hybridization strategies.


Michael DurackMichael Durack
Technology Director & Managing Director
Ultimate Transmissions

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