Nearly all car manufacturers are working to get the best fuel consumption from their engines. A few successful options have already been accepted by consumers. Now comes another method that’s gaining attention. This is a system to recover lost heat energy. It is the Turbosteamer and Thermoelectric Generator systems which BMW have researched for much of the last decade as part of its EfficientDynamics initiative to maintain performance while using far less fuel. Each uses waste heat from the radiator or engine exhaust to produce electricity that can power auxiliary functions like air conditioning and electric power steering.
Power from steam, and Seebeck Effect
The BMW Turbosteamer boils a fluid, stored at high pressure in coils that wrap around parts of a car’s exhaust system. As it boils, the fluid turns into steam that powers a turbine that turns an electric generator. The Thermoelectric Generator, on the other hand, generates an electric voltage in a special material via the Seebeck Effect, in which potential is created between two different thermoelectric semiconductors if their temperature differs. That technology was originally developed to power space vehicles by the U.S. National Aeronautics & Space Administration, better known as NASA. With recent refinements to produce more power, the Thermoelectric Generator produces up to 600 watts in the latest BMW application, where it’s installed in the radiator of a car’s exhaust-gas recirculation system. To be practical in a production car, BMW says, it will have to generate at least 1,000 watts (or 1 kilowatt).
10 percent efficiency improvement
BMW has configured the two systems into a single module that can be fitted into a production vehicle. Initial tests using a four-cylinder engine indicate that fuel consumption can be reduced by up to 10 percent on long-distance, high-speed trips. BMW will display the Turbosteamer in a BMW 5-Series sedan at the upcoming Frankfurt Motor Show; the Thermoelectric Generator is presently being tested in a BMW X6.
