Diesel Fuel Additives
The main purpose of diesel fuel additives is to maintain the function and condition of the fuel delivery system. Diesel fuel additives may be formulated for occasional use. Some examples could be to clean injectors, address changes in ambient operating temperatures or combat fuel quality issues. Additives are most effective, however, when used on a continuous basis, especially to prevent wear and deposits.
The following types of additives, which many additive companies combine for ease of use, are designed for specific purposes.
Cetane number improvers increase the overall efficiency of diesel fuel combustion. This results in reduced engine noise and smoke, lower emissions and better cold weather starting.
Injector cleaning additives are formulated to avoid internal diesel injector deposits and external deposits from forming in the nozzle. Fuel injectors are vital components of the fuel delivery system. They require continuous maintenance to ensure proper operation.
Lubricity additives are used to combat the low lubricity associated with ultra low sulfur diesel. Fuel pumps and injectors need lubricity additives to lower wear from metal to metal contact.
De icing additives use alcohols or glycols to prevent ice formation. This can result in blocked fuel lines and a blocked fuel filter. The alcohols and glycols act by dissolving in water, lowering the diesel fuel’s freezing point.
Additives that lower a diesel fuel’s pour point are called low temperature operability additives. They are also known as cold flow improvers. Most of these additives are polymers that combat the wax crystals and help lessen their effect on the fuel flow. This can be achieved by modifying their shape. Anti oxidants can be added to unstable fuels to fight the chain reactions associated with oxidation. Acid based reactions create fuel instability, and the stabilizers needed to prevent these reactions typically are strong basic amines. When small amounts of certain metals are dissolved in diesel fuel, such as copper or iron, a metal deactivator is needed.
Contaminant control additives handle the chemical pollutant problems associated with diesel fuel supply and storage. Fuel can become contaminated with bacteria and fungi due to air or water exposure. These types of additives are designed to control or eliminate contaminants from becoming larger issues. A small number of contaminants may not be a problem, but excessive contamination can corrode the fuel system and plug filters. This happens most in stored fuel, and the best additive to use is a biocide that readily mixes with both fuel and water. Demulsifies and corrosion inhibitors also help contain contamination.