today

Hopefully the power unit is to be built on a silicon chip at the Massachusetts Institute of Technology and the engine is about the size of a 50p piece. It basically consists of a compressor, a combustion chamber and a spinning turbine. Etched silicon is used to construct it. The resulting microengine is made up of six silicon wafers piled on top of each other and bonded together. To bring down costs, up to 100 components are made on one large wafer and cut into individual units. The process begins with a tiny combustion chamber where fuel and air mix and burn at the melting point of steel. Turbine blades spin at 20,000 revolutions per second.

A mini-generator produces 10 watts of power and a tiny compressor raises the pressure of air in preparation for combustion. The cooling process is managed by sending the compression air around the outside of the combustor.

Separately it has apparently been proved that all the parts work so the challenge now is to test an integrated chip and it is hoped that a successful model, which may eventually lead to a steam powered unit, will be available by the end of this year.