INTRODUCTION This chapter presents the background of the study, the indicators of scavenging fire, the reasons of scavenge fire, the actions needed to prevent scavenge fire, and its effect to the engine and operation.
Two stroke crosshead engines are the most powerful diesel engines in the world. These engines have cylinder bores approaching 1metre with a stroke of over 2.5 meters. The crankshaft can weigh over 300 tons, with the engine weighing in excess of 2000 tons. Crosshead type of 2 stroke engines are the most used machine in the sea. There are two types of spaces that separates this type of engine. One is combustion space, it is formed by the cylinder liner, piston and cylinder head; and two is the scavenge space which is separated…show more content… The source of ignition comes from the sparks in the combustion area passing the piston rings and coming in contact with the flammable oil. It is part of the watch keeping engineers remit to be familiar with the causes, control and prevention of scavenge fires in the main engine. It is also imperative that the scavenge spaces should be cleaned out at every opportunity in port and regular inspection of the scavenge drains to the sludge tank carried out by the watch keeper (Willie Scott,…show more content… First, the blow past of combustion products which are caused by leaky, sticky or broken piston rings, worn out liner, defective cylinder lubrication, or lacking axial clearance of the piston rings. Second, the overheated piston which dissipates heat to the under-piston area caused by defective atomization and injection pressure, defective fuel pump timing, loss of compression, engine overload, failure of coolant circulation or insufficient cooling due to formation of scale. Third, the blow back of exhaust gases which is caused by exhaust back pressure or deposits on exhaust ports, fouling of grid before turbine inlet, fouling of turbine blades, choking of Exhaust Gas Boiler (EGB) or economizer gas outlet. Fourth, the presence of fuel oil in the scavenge spaces due to the defective fuel injectors, the incorrect pressure setting of injectors or fuel particles landing on the cylinder liner due to excessive penetration. Fifth, the excessive cylinder lubrication which is drained down to scavenge spaces. Sixth, there are plenty of oxygen during engine operation. Lastly, the multiple fouled