- In general, fuels leaving the refinery have sodium content well below 50mg/kg. If the sodium content increases, which is normally caused due to seawater contamination. A 1% seawater contamination represents potentially a 100mg/kg increase.
- Vanadium is also present in the fuel oil, which combines with oxygen to form V2O5 (vanadium pentoxide), which combines with sodium to form sodium/vanadium complexes. It is well known that there are low melting temperatures of sodium/vanadium complexes of certain critical ratios.
- The most critical sodium/vanadium ratio is about 1:3. This will form a sodium/vanadium complex with a low melting point which will flow with the exhaust gases.
- It will get deposited as a hard and brittle layer on the cold surfaces such as exhaust valve spindles, turbocharger nozzles and turbine blades. This layer is highly corrosive and corrodes the metal. It is also brittle and breaks away exposing the metal for fresh attack especially when they get deposited on exhaust valve seats. The hard layer breaks and gives a cutting effect on the seat.
- Preventive measures can be taken such as keeping the temperature of the exhaust below the melting point of V2O5 and removal of sodium by proper purification and proper draining of the settling tanks. Therefore high sodium content in the fuel oil will result in corrosion and grooving of exhaust valves.
The electrohydraulic control mechanisms of the ME engine replace the following components of the conventional MC engine: Chain drive for camshaft Camshaft with fuel cams, exhaust cams and indicator cams Fuel pump actuating gear, including roller guides and reversing mechanism Conventional fuel pressure booster and VIT system Exhaust valve actuating gear and roller guides Engine driven starting air distributor Electronic governor with actuator Regulating shaft Engine side control console Mechanical cylinder lubricators. The Engine Control System of the ME engine comprises: Control units Hydraulic power supply unit Hydraulic cylinder units, including: Electronically controlled fuel injection, and Electronically controlled exhaust valve activation Electronically controlled starting air valves Electronically controlled auxiliary blowers Integrated electronic governor functions Tacho system Electronically controlled Alpha lubricators