Ceramic Valves. A valve is a piece of material that moves in and out of an opening to either block or allow flow through the opening.
Valves are used in gasoline and diesel engines to let the air-fuel mixture into the cylinder that houses the piston and also to let out the hot exhaust gases after the air-fuel mixture has been ignited by a spark from the spark plug.
The valves, which are presently made of metal, are exposed to the full force and temperature of the exploding gas-fuel mixture.
Replacing the metal valves with a higher-temperature and lower-weight material would increase valve life and increase engine efficiency.
Ten years ago, automotive manufacturers didn't believe that ceramics could survive as an engine valve, but they were wrong.
Siliconnitride, the same high-strength ceramic that works so well for bearings and cutting tools, also works beautifully for engine valves.
Siliconnitride valves have been run in high-performance race car engines, where materials are pushed to their limits.
They have also been run in passenger cars by several different automotive companies.
The most aggressive automotive company has probably been Daimler Benz.
They've successfully tested siliconnitride valves in engines in the laboratory and on the road for hundreds of thousands of miles and have proved that these ceramics meet all of the reliability requirements.
The only thing keeping them from putting ceramic valves into production is cost, but Daimler Benz is also getting very close there.
Don't be surprised to see cars with siliconnitride valves available in your dealer's showroom within the next few years.