IT'S not going to happen overnight. But if current research pays off, automobile engines will increasingly be made of a substance that's light, strong, and energy-efficient: ceramics. Some ceramic parts, of course, have long been used in the auto business. Spark plugs and some electronic components are ceramic, as are elements of the pollution-control systems in some of today's cars. There have been predictions that an ``adiabatic,'' or all-ceramic, engine - needing no radiator or cooling system, because it would allow no loss or gain of heat - would arrive by the year 2000.
Don't count on it, says Merton Flemings of the Massachusetts Institute of Technology, who sees ``absolutely no chance'' for an adiabatic engine in this century.
``The ceramic engine itself is a misnomer,'' says Richard B. McNamara, vice-president of ceramics for the Norton Company, Worcester, Mass. ``But the application of ceramics to engines is real,'' he notes. Norton is putting its money on the line in a joint venture with TRW Inc., to develop advanced automotive ceramics.
``We're looking for ways to ceramify the whole combustion chamber - the cylinder walls, piston cap, head, valves, and the sticking of ceramics to metal,'' Mr. McNamara says.
Ceramic parts are roughly 40 percent the weight of an equivalent metal component, and, if used on a larger scale, could someday lead to smaller engines and raise fuel economy as much as 20 percent. Ceramic parts could also outlast metal.
``By using a lighter-weight valve, you can theoretically cut the valve-spring force by about 40 percent,'' says McNamara. ``Thus it would take less energy to move the valve up and down. This translates into lower friction, which, in turn, means better fuel economy. Or you can take the light weight of the valve system, using the existing valve-spring loads, and get higher engine r.p.m., which means more output.''
Already there are a lot of developments in ceramics around the world, particularly in Japan. While the Japanese appear to have backed off from the high-heat adiabatic engine, some Mitsubishi engines already have ceramic parts, as do the turbochargers used by Nissan.
In the United States, Allied Signal's Garrett subsidiary, a major turbocharger producer, says it may soon put a ceramic rotor into production. Light and strong, a ceramic rotor could reduce turbo lag by taking less time to reach its operating speed. Also, ceramics would allow a higher-temperature exhaust in the turbocharger system.
Robert Frosch, director of the General Motors Research Laboratories, warns of problems still ahead. Ceramics, he says, are brittle. ``We're looking for ways that will make them more uniform and more controllable. Part of the problem has been not just that they break, but that they're different from metals or polymers, where the materials have fairly predictable characteristics. Simply, they deform and then break in understood ways. They don't break arbitrarily, as do ceramics.
``Ceramics have the bad habit of being extremely variable. Nothing whatever happens, and then the part goes smash. It isn't even precisely at the same stress level.'' Also, when metal and ceramics are used together, there is a difference in the thermal expansion and contraction of materials. McNamara says that Norton is working with the federal government's Oak Ridge Laboratory in Tennessee ``on ceramics-to-metal joining, in which we're trying to defeat the thermal-mismatch problem.''
Despite the problems still to be solved before the widespread application of ceramics to automotive engines, some observers predict that the automotive and aerospace industries could be spending as much as $10 billion on ceramics on by the year 2000. While Norton's McNamara backs off from the $10 billion figure, he says ``it certainly will be in the billions of dollars.''