Waste Heat Recovery Systems for Fuel Economy

The largest automakers strive to reduce carbon dioxide emissions to meet regulations by improving engine efficiency. A device that recovers a portion of the heat wasted in the exhaust gas could be a highly effective solution. It is believed that the most appealing technology is the Organic Rankine Cycle for its ability to recover heat from low temperature sources and its limited costs. However, Waste Heat Recovery (WHR) is still far from being employed in mass production light duty vehicles because there are still several unsolved problems. To assess the feasibility of such devices it is fundamental to develop a simulation tool able to replicate the behavior of a WHR system. This thesis discusses the main topics and pitfalls associated with the application of an Organic Rankine Cycle to recover energy in the operating of light duty vehicles. The simulation tool which was developed by the author to compare the design alternatives and quantify the potential benefits in terms of amount of energy that can be recovered, is illustrated and its functioning is explained in details. The simulation results are thoroughly examined