Si ₃ N ₄ Ceramic Valves for Internal Combustion Engines

Silicon nitride (SN) valves promise significant reductions in weight and inertial force for valve trains because they are only two-fifths the weight of equivalent metal versions. This study evaluates how the higher engine speeds and lower valve spring loads that they permit contribute to higher engine output and greater fuel economy.

It also evaluates their reliability in the presence of valve bounce and other adverse conditions that ceramic valves normally fail to withstand. For this purpose, material studies, actual engine tests and finite element method (FEM) analysis were conducted. Long-term durability tests revealed that SN valves are capable of providing the necessary resistance to breakage.