The unique characteristics of the Torotrak IVT are best achieved through a fully integrated powertrain control, rather than as separate engine and transmission components.
Torque control
In a conventional ratio controlled transmission the power from the engine is transmitted directly to the drive wheels through the transmission. The driving force is determined directly by the engine operating point and the transmission ratio.
The Torotrak IVT is a torque-controlled transmission. An electronically controlled pressure applied to the Variator sets the torque seen at the drive wheels. The engine throttle is then set to match the load generated by the Variator and the engine speed is maintained.
In a normal automatic the driver sets the engine torque demand, the computer sets the ratio, resulting in wheel torque.
In a Torotrak IVT the driver sets the wheel torque demand, the computer sets the engine torque and speed, resulting in ratio.
Control system design
Torotrak uses advanced electronics to quickly adapt and develop IVT to match the needs of our customers. The control system is developed in a “rapid prototyping” environment where control code is generated automatically from block diagrams and flow charts. In production these algorithms will be integrated into the standard vehicle electronic control units.
High performance with economy
By responding to driver demand - expressed through the accelerator pedal - and monitoring the engine, vehicle and transmission, the software algorithms generate control decisions for the engine throttle and transmission hydraulic system. This level of control can produce high performance when required, coupled with economy at all other times.
Flexibility of powertrain design
With the Torotrak IVT the driver 'drives' the transmission rather than the engine. This releases the engine from the constraints of driveability, allowing it to be run for optimal economy, emissions or, when required, ultimate performance. Consequently the Torotrak IVT provides ample opportunity for manufacturers to meet the ever more demanding legal requirements for fuel economy and emissions without sacrificing driveability or performance.
Benefits of optimum control
In essence, the degree of control freedom the Torotrak IVT offers ensures the engine can always be run at its optimum operating conditions. This results in:
- Improved economy
- Better performance
- Reduced emissions
- Smoother operation
- Lower overall noise levels
Flexibility of driving mode
Microprocessor control has almost unlimited potential to programme the transmission to exactly suit the individual driver's preferences. For example:
Recent developments have demonstrated that the Torotrak IVT can produce the characteristic feel of a torque convertor equipped automatic transmission. On the other hand, Torotrak IVTs can be programmed to mimic the feel of manual transmissions - satisfying the dedicated manual driver.
