Air start system

The air start system on a large slow speed diesel engine is made up of the following components; compressor, air reservoir (large cylindrical tank) associated piping, control valve (this is linked to the camshaft) and the air start valve.

On starting the engine, air is admitted to whichever cylinder has a piston just over top dead center, as the engine starts to turn the air start valve on the next cylinder in line opens to continue the rotary movement. As the engine contiues to rotate, fuel is injected into the cylinders, the engine is then under way and the air is cut off.