It is well known that only a third of the energy provided by gasoline is used, much of it being lost through the heat released. Better control this heat, it is to increase the power while decreasing the consumption, it is to say if the subject is sensitive at all the car manufacturers.
Based on the principle of the steam engine, BMW has developed a technology called "TurboSteamer" to recycle this heat into energy. Promising results would have revealed an increase in the power of 13ch and 20Nm while the consumption drops 15% on a 4 1.8l cylinders mounted on a bench.
The principle is very complex but can be schematically summarized as follows: a water tank is heated by the exhaust line to 550 ° and the steam under pressure thus obtained is discharged into a specific expansion vessel and will be used to increase the pressure in the cylinders, in the spirit of a compressor. In this way, more than 80% of the heat energy contained in the exhaust gas can be recovered.
However, this technology can only be applied to gasoline engines, since diesel engines do not provide enough heat to be sufficiently efficient.
The Turbosteamer is the first provisional result after five years of intensive research work. The further development of the concept must now focus primarily on reducing and simplifying the different components. The long-term goal of the research project is to make it a series system, an objective that BMW believes is possible within the next ten years.