A range of spring loaded poppet valves designed to automatically stop the engine by closing the air intake should excessive overspeeding occur.

These D Valves are available for engines up to 805hp with air intake diameters of up to 229mm.

Once the engine has shutdown, the valve will be automatically reset.

Manual shutdown options are available with various length cables and different handles.

For small single cylinder engines, Chalwyn build the D valves with combined air cleaners.