Engine valves are mechanical components used in internal combustion engines to allow or restrict the flow of fluid or gas to and from the combustion chambers or cylinders during engine operation. Functionally, they perform similarly to many other types of valves in that they block or pass flow, however, they are a purely mechanical device that interfaces with other engine components such as rocker arms in order to open and close in the correct sequence and with the correct timing. Engine valves provide precise, reliable control of critical engine functions for turbine clearance control, compressor bleed, anti-ice and engine start. Engine valve portfolio includes over 900 unique valve designs that are used on more than 200 different aircraft platforms. Typical applications include engine core compartment cooling, turbine active clearance control, transient bleed valves and nacelle anti-ice.