4.1 Feature
4.1.1 High reliability and endurance
(1) By introducing structure of the underslung main bearing, strength and rigidity of each component is improved and reliability is ensured against increase of the maximum pressure of combustion.
(2) All bolts for the cylinder head, main bearing and connecting rod are carried out by hydraulic tightening by means of special hydraulic tool (connecting rod of 6N18L is angle tightening). This mode is designed for labor-saving at time of assembling and disassembling and ensures sure tightening force and makes it possible to operate for a long time without overhauling.
(3) In consideration of deformation and heat load, we have carried out forced cooling at the peripheral part under the cylinder liner collar, thin wall by means of inclined rib structure of the cylinder head combustion face and forced cooling between valves for the purpose of extending the life of parts.
4.1.2 Direct burning of heavy fuel oil is possible
(1) By adopting high pressure type injection pump, pinion lubrication etc., the engine can directly burn 700cSt at 50℃, heavy fuel oil and is based on the mono-fuel system where the same fuel can be used as in the main engine.
(2) In consideration of use of heavy fuel oil, the cooling type exhaust valveseat is adopted, laser hardening is given to piston ring groove, and nitriding treatment is given inside the cylinder liner, for the purpose of improving reliability and durability.
