From the early '80s the motorcycle industry has been telling us that the future of the internal combustion engine lay in ceramics rather than metal, and that the result of the switch would be a revolution in massive power-to-weight ratios, frugal economy and ultra-clean emissions.
Time has past and we're still waiting for ceramic engines. On the face of it, once you'd come to terms with the idea of your engine being made from the stuff of chinaware, the idea seemed to be genius. Ceramics are far lighter than even aluminum, can be made with endless different properties, including immense strength, the ability to withstand – and insulate – incredible temperatures, and be close to frictionless without the need for messy oil-based lubrication.
When it cam to using ceramics in engines, the big bonus was their ability to cope with heat without expanding or melting, and several motorcycle manufacturers built prototypes to prove it. Heat is one of the single biggest problems of any internal combustion engine. It's unavoidable; when you burn petrol, your engine's going to get hot. But too much heat melts metal, so we need extensive cooling systems to take it away. The result is that a huge amount of the potential power of an engine is stolen – it's converted to heat, transferred to the cooling liquid, pumped into a radiator and expelled into the air in a constant cycle.
But if you can create a ceramic engine that contains all the heat, refusing to let it radiate outwards, that cooling system becomes unnecessary. Better still, with temperatures in the cylinder spiraling upwards to somewhere in the region of 6,000 degrees centigrade – way past the point at which you'd melt the pistons of a normal, metal engine – petrol can be burnt at a much leaner mixture than the normal 14.7:1 stoichiometric combustion ratio, and alternative fuels, like alcohol or ethanol, become more viable engine – the prototype ceramic engines were able to convert far more of the energy from burning fuel into power, with some designs claiming to convert more than 50 percent of the energy contained in their fuel into usable power. A really good, modern conventional petrol engine manages around 30 percent efficiency.
Currently some motorcycle manufacturers produce engines that have ceramic cylinder bore coating to reduce friction, the ceramic cylinder bore coating offers an average 4 percent performance gain.