At the heart of the technological advantage of the IVT is its inherent ability to allow the engine to run under optimum conditions. This advantage, when applied to a parallel-hybrid, allows car companies to provide the principal benefits of complex split-hybrid configuration but within a conventional vehicle layout. (A guide to the different type of hybrid electric systems can be seen here.)
The parallel hybrid system allows for a modular approach where the same vehicle can be offered with an IVT alone or with the addition of an electric motor for those customers who choose a hybrid electric version of the vehicle. This will allow vehicle manufacturers to respond quickly to the varying customer demand for hybrid electric vehicles.
Unlike most hybrids, which are relatively inefficient in steady state cruise conditions, the parallel IVT demonstrates high efficiency in real world driving conditions.
The diagram below shows a typical IVT hybrid configuration.
Torotrak is involved in a collaborative programme with Cranfield University to study the benefits of an IVT when applied to a parallel hybrid vehicle. Early modelling results predict a greater than 35% improvement in fuel economy with the parallel hybrid IVT when compared with standard fixed ratio automatics.
This level of fuel economy improvement compares favourably with some of the more complex and expensive hybrid architectures that are currently under evaluation by the automotive industry.
