Air Starting of Marine Diesel Engines

By ShashankMech –B

Roll No. -82Reg No.- 080909328

INTRODUCTIONLarge Marine Diesel Engines are started

using high pressure compressed air. To minimise the risk of an air start

explosion, fuel is not injected into the cylinder whilst the air is being admitted.

There is a means to start the engine locally as well as from The Bridge .

International Association of Classification Society rules state

To protect starting air mains against explosion arising from improper functioning of starting valves

i. An isolation non-return valveii. A bursting disc or flame arrester

Different Parts at a glance

Air start valve When opened by the air signal from the distributor, compressed air at flows into the cylinder, forcing the piston down.

Bursting disk 1. A FLAME TRAP can also be used.2. Limits any pressure rise due to explosion by bursting.

Automatic valve Open only during air startingIncorporates

1. Non return valve 2. Slow turn valve

Air distributor One end attached to air main start valveHas number of pilot valvesOperated by means of a cam

Turning Gear Interlock If the turning gear is engaged ,this stops high

pressure air from reaching the air start control valve and thus the automatic valve

Air Start ReceiversCapacity of the receiversFunction of the receiverPressure gauge and drain are attachedManhole for inspection purposes

Air compressorsCharges the air receivers .Usually two stage reciprocating with inter

and after stage cooling are used. Relief valves are fit to each stage as is a high

temperature cut out.Intercoolers are fitted with taps on the water

side.

Thank You