In recent years, the steep rise in the price of crude oil and the demand for light oils; such as gasoline, kerosene and diesel oil, and the increased sophistication of oil refining technology, had led to a tendency towards the production of low quality marine residual fuel oil (hereinafter MFO) . Among the many types of degradation, the deterioration of the ignition and combustion quality of MFO in large marine diesel engines is of particular concern, as this causes such problems as poor combustion in diesel engines. In addition, there is an increasingly greater risk that these problems will be associated with serious problems, such as piston ring damage and abnormal wear on the cylinder liner.
The technical information here presents the results of the ignition and combustion qualities, and the general properties of actual marine fuel oil analysis. We used a constant volume combustion chamber instrument (Fuel Ignition Analyzer such as FIA) . Further, we describe the relationships between ignition, combustion quality, and the general properties and engine problems. Examples of countermeasures are described so that these problems caused by fuel oil, with poor ignition and combustion quality, can be avoided.
