Effects of Poor Fuel Quality
Poor physical properties of diesel fuel will affect the reliability of diesel engines. Diesel fuel is intended to cool and lubricate the fuel injection system. Poor lubricity will result in excessive wear and premature failure of injectors and fuel pump. Poor lubricity can be due to inadequate manufacturing of the fuel, using improper solvents or low quality additives. Severe processing of fuels can reduce the amount of surface protecting agents within the fuel. Fuels that are a heavier grade (require less refinement) will create combustion chamber deposits. These deposits will reduce the life of cylinder liners and rings. Low cetane numbers will also damage engines damage over time, resulting in engine knock, trouble starting, and black exhaust smoke.
Dirt and water are the most significant contamination factors found in diesel fuel. In some instances, fuel is replaced with water, kerosene, or other fluids between the refinery and the fuel pump in order to make a larger profit. Most natural contamination (dirt and water) originates from onsite storage tanks, delivery methods to fuel tanks, and fuel tanks themselves.
Injector Life Reduction: Injector life is reduced by about half with water content above acceptable levels. Water content should optimally stay well under 0.05% of volume. When fuel contains water, it will begin to show a haze and become more opaque. Water content above 0 .05% will cause damage to the fuel injection system.
Lubricity Reduction: The lubricating properties of diesel fuel are also affected by moisture displacing the fuel. When water passes through an injector, it immediately vaporizes, turning into steam. This high pressure process can damage the injector tips over time. Water also reduces the combustibility of the fuel being injected.
Bacterial Growth: Water promotes bacterial growth, which results in acidic conditions. These conditions promote corrosion in engine and fuel system components.
Asphaltene Formation: Asphaltenes can plug filters and damage injectors. They can also affect the combustion efficiency of the engine. Improper fuel droplet size due to damaged injectors, combined with asphaltene particulates, require higher temperatures and compression to fully combust.