Back in 2005 BMW showed an interesting concept device that was designed to increase the overall efficiency of conventional ICEs. This system is dubbed the turbosteamer. It seems like an elegant way to recover energy that is otherwise wasted.

One of the better articles about the turbosteamer can be found: Here. Another article which includes the official BMW info about the system is: Here.

The system is based on the well-known and thoroughly developed technology of steam engines. Basically there are two circuits involved, a high pressure high heat circuit and a low pressure low heat circuit. The high pressure circuit uses water as the base medium and the low pressure circuit uses ethanol as the base medium.

The base engine in the prototype is BMW's N46B18 1.8L I4 that produces 115hp stock. According to the claims the system can extract over 80% of the waste heat from the exhaust. The steam system produces an extra 14hp bringing total engine output up to 129HP. Fuel consumption is reduced by 15%.

Now comes a question to be answered: How efficient is the turbosteamer system???