High-tech cars to make power from exhaust heat

Hydrogen car
Who needs hydrogen cars when we can harvest the heat from good old exhaust fumes?

If you've ever wondered why the heat from a car's engine can't be captured and converted into electricity (and who hasn't, frankly?), then you're in good company – that's precisely what a bunch of clever Japanese engineers have just managed to achieve.

The boffins at Tokyo-based Furukawa have solved a tricky engineering problem to create a thermoelectric conversion system that sits between the engine and the exhaust in a car to generate power from the hot gases.

Heat gradient

The tiny devices – 20 are used per car in the current prototype – work because they are made of a mineral that can maintain the heat differential between its two sides that is needed for the generation of electricity.

The skutterudite-based material keeps its hottest face at 720º C, while the opposite side can remain at around 50ºC with the aid of a little water-cooling. This allows the converter to operate properly and generate up to 33W of electricity.

Fuel saving

Apparently, that means 7 per cent of exhaust heat becomes electricity that can partially power a car, thereby reducing fuel consumption by 2 per cent. Furukawa says a commercial version should be ready in about three years.

Oh, and in case you're wondering, "Skutterudite is a cobalt arsenide mineral that has variable amounts of nickel and iron substituting for cobalt". So there.