Valves
Valves are used to ventilate an engine. During the compression and combustion cycle, they seal off the channels to and from the
combustion chamber and during intake and exhaust they release the gas lines. Air is brought into the chamber via inlet valves;
combusted gases are ejected to the exhaust via outlet valves. The ensuing enormous thermal loads place a great strain on the materials
used. Two, three or four valves are used per combustion chamber in ships' engines. The inlet valves, which are vented and cooled in
every combustion cycle, attain a valve disc temperature of over 500°C. The outlet valves, however, reach temperatures over 800°C.
They absorb heat during both the combustion cycle and the exhaust cycle and cool down by emitting heat from the valve seat and the valve
spindle on the valve guide.
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