sixth semester

On some large bore, long stroke engines it was found that undercooling 1 FAR down the liner was taking place. Why is this a problem? The hydrogen in the fuel combines with the oxygen and burns to form water. 2 NORMAL this is in the form of steam, but if it is cooled it will condense on the liner surface and wash away the lube oil film. Fuels also contain sulphur, which burns in the oxygen and the products combine with the water to form 3 SULPHUR acid. If this condenses on the liner surface, then 4 CORRODE can take place. Once the oil film has been destroyed then wear will take place at an 5 ALARM rate. One solution is to insulate the outside of the liner so that there is a 6 REDUCE in the cooling effect. On the latest engines, the liner is only cooled by water at the very top, relying on the air in the scavenge space to cool the lower part of the liner.