Abstract
A mechanical hybrid vehicle driveline, incorporating a flywheel with high specific power density, a belt type continuously variable transmission (CVT) and an intermittently operated spark ignition IC engine, has successfully been developed and tested. The development of a detailed computer simulation model enabled the subdivision of energy flows and the location of energy losses in the driveline. The model is described in terms of physical components and experimentally obtained energy loss relations. The systems energy saving potential is discussed in the paper. Both measurements and calculations show that optimisation of the system and its components gives way to a significant improvement of total fuel economy.