Energy Recovery Systems for Engines 2008-01-0309

Energy recovery from IC engines has proved to be of considerable interest across the range of vehicle applications. The motivation is substantial fuel economy gain that can be achieved with a minimal affect on the “host” technology of the vehicle.

This paper reviews the initial results of a research project whose objective has been to identify system concepts and control methods for thermal recovery techniques. A vapour power cycle is the means of energy transfer. The architecture of the system is considered along with support of the fuel economy claims with the results of some hybrid vehicle modelling. An overview of the latest experimental equipment and design of the heat exchanger is presented. The choice of control architecture and strategy, whose goal is overall efficiency of the engine system, is presented and discussed. Some initial control results are presented. One important project aim is to identify and implement an optimal control method that allows an explicit balance, between the IC engine output and the recovered work from the vapour power cycle.

Initial simulation work shows that there are significant, potential, fuel economy advantages, between 6% and 31%, and that high efficiencies can be achieved at practical operating pressures. Conclusions point to the need to investigate and develop the system control dynamics.