Release: July 18, 1997
(Mercedes-Benz started a large scale field test with 1750 Mercedes C230 Compressor engines installed with ceramic valves)
NGK Insulators, Ltd. (President: Masaharu Shibata, Head Office; Nagoya) has provided ceramic valves for automotive engines to Mercedes-Benz (Germany) for its C230 Compressor since June 1997. (C230 Compressor --- Displacement: 2.3 liter, Model: Straight 4 cylinder 16 valves with super charger, Max. engine power: 142kw/5,300rpm, Max. torque: 280Nm/2,500 - 4,800rpm) The limited number of 1750 engines installed with ceramic valves are now field tested. Based on their results, Mercedes-Benz will consider gradually applying ceramic valves to other models.
NGK joined R&D of ceramic valves initiated by Mercedes-Benz approximately 10 years ago. In October, 1993, as a R&D base, NGK established NGK Ceramics Europe S.A. (President: Shun Matsushita (Director, NGK Insulators, Ltd.), Head Office: Baudour, Wallonne, Belgium), which has conducted several kinds of tests, such as an ability evaluation test by actually driving a car. On the other hand, Mercedes-Benz has already conducted a bench test with 17 engines for more than 8,500 hours; in addition, a driving test of 300,000 km. The favorable results from these tests impelled Mercedes-Benz to a large scale field test.
The applied ceramic valves are made of silicon nitride and approximately 60% lighter than the regular steel valves. This results in the advantages that fuel consumption is reduced due to decrease of friction loss, and the noise level of the engine is lowered. Thanks to the development of mass production technology, we obtained a prospect that the price for ceramic valves might come close to that for sodium sealed valves.
NGK has developed automotive ceramic products, such as a honeycomb substrate for automotive exhaust gas purification and a ceramic turbocharger rotor; however, this is the first time to employ ceramics for valves which are key components in valve train system. From the point of technology, to adapt ceramics to the parts which are required to stand extreme strain in engines is a revolutionary attempt. NGK anticipates net sales of 1 billion yen after 2000.