THE internal combustion engine took a giant leap forward last week when an
American scientist showed how to extract more energy from a car’s exhaust gases
than was ever thought possible. The trick? Turn the exhaust system into a
laser.
Since the four-stroke petrol engine was invented in the mid-19th century,
engineers have been striving to extract the last ounce of power from it, guided
by the laws of thermodynamics. These laws predict that an engine’s efficiency is
ultimately limited by the temperature of the gases as they burn.
As the hot gases expand, they drive a piston through a…
