Ceramic Engine Valves

Abstract

Current trends in spark ignition engines are toward multivalve engines capable of operating at relatively high speeds to maximize performance and fuel economy at acceptable emissions levels. Structural ceramics, with their low density and good high‐temperature properties, appear to offer potential as an alternative valve material to the steels, superalloys, and titanium alloys currently in use. Progress to date on materials development, component design, component performance, and engine testing indicates that silicon nitride valves will operate satisfactorily.