Silicon nitride valves for automotive engines

Silicon nitride (SN) has matured to a high strength and highly reliable ceramic material over the last decade, fulfilling the requirements of active components in high-performance applications. Among those, valves for automotive engines are at the center of attention, as SN valves offer a range of advantages compared to conventional metallic parts. In this paper, the state of development of materials and components, quality assurance, as well as results of application tests with various passenger cars are outlined. Economical aspects are also discussed.