Recycling heat

摘要

The limits of internal combustion mean that only a third of the chemical energy in gasoline and diesel's expensive hydrocarbon molecules is converted into useful work at your engine's crankshaft. What to do with the other two thirds, rejected as heat to the coolant and into the exhaust, is becoming a lot more important as OEMs look for the most cost-effective ways of improving fuel consumption. BMW, among others, is developing thermoelectric generators (TEGs) to tackle this problem. They use the so-called Seebeck effect, whereby a semiconductor generates an electric current when a temperature gradient is applied to it. The electricity can be fed into the vehicle network.