MUNICH – BMW is reviving steam-engine principles in an auxiliary drive that it says can boost both power and fuel efficiency in ordinary piston-driven cars.
The automaker is testing a two-stage device called the Turbosteamer on a stationary conventional 1.8-liter engine at BMW headquarters here. The device works entirely on the waste heat from the engine. It converts more than 80 percent of the heat energy in the exhaust into usable power, said Raymond Freymann, head of BMWs advanced research and development subsidiary.
BMW could start building production vehicles with the system by the first half of the next decade, Burkhard Göschel, BMW board member for r&d, said in a briefing. It can be used on any combustion engine.
In trials on a test rig, the system when attached to a regular BMW four-cylinder,
1.8-liter Valvetronic engine reduced fuel consumption figures by 15 percent – and also generated an extra 13hp and 20Nm of torque.
The concept is hardly new – the first patent for a steam auxiliary drive harnessing exhaust heat was issued in 1914 to Wilhelm Schmidt of Germany.
The sheer size of a heat-recovery system had been the biggest problem in the past. But the Turbosteamer fits in a regular 3 series body.
All we lose is a bit of ground clearance, Freymann said.