When people generally think about downsized, highly boosted engines, they probably don’t take into account the fact that because within the cylinders there are higher peak temperatures and pressures, there are significant demands placed on . . . the spark plugs. What’s more, lean fuel mixtures and alternative fuels are more difficult to ignite.
And because the engines are smaller, because there are four valves, because there is direct injection and so there needs to be space for the fuel injector in the combustion chamber, and because the need for more space for coolant packages to help manage the thermal loads . . . there is less space for the spark plugs.
To address this, Federal-Mogul (federalmogul.com) has developed a new high-performance spark plug ceramic, SureFire Plus, that allows the manufacture of spark plugs that can deliver voltages of 42 kV or more (compared with 36 kV) and have a smaller diameter, 10 mm, for example, rather than 14 mm. Whereas spark plug insulators are generally made with 95% alumina and 5% glass, the new Federal-Mogul material is said to have “a significantly higher percentage” of alumina and the balance of various oxides that serve to minimize electrical current leakage through the ceramic material.
The characteristics of the material have required the development of a new manufacturing process to produce it. Rich Keller, director of product ignition engineering, Bearings & Ignition, Federal-Mogul Powertrain, said, “Developing a ceramic microstructure with superior resistance to high-voltage breakdown was a vital first step, but to make SureFire Plus a production reality required a develop-ment breakthrough in compaction process technology.” Federal-Mogul
plans to have SureFire Plus in high-volume production by May 2014.