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Maintenance Section Fuel Specifications
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Characteristics of Diesel Fuel
SMCS Code: 1250; 1280
The primary characteristics that affect engine operation and performance in cold temperatures are the following characteristics: Lubricity, Viscosity, Cetane Number, Cloud Point, Pour Point, and Moisture Content.
Refer to Special Publication, SEBD0717, “Diesel Fuels and Your Engine” for information about the following fuel properties: ignition quality, gravity (density), viscosity, cloud point, pour point, and sulfur content.
Lubricity and Low Sulfur Fuel
Note: The fuel lubricity is important. You should consider the fuel’s lubricity whenever you operate the equipment in arctic weather. Also, you should consider the fuel’s lubricity whenever you use fuels that are lower in viscosity. There are many aftermarket additives that are available to treat fuel. If the fuel’s lubricity is an issue, consult your fuel supplier for proper recommendations regarding fuel additives.
In the USA, a 0.05 percent limit on the amount of fuel sulfur in diesel fuel was mandated in January of 1994 for
The fluid’s lubricity describes the ability of the fluid to reduce the friction between surfaces that are under load. This ability reduces the damage that is caused by friction. Fuel injection systems rely on the lubricating properties of the fuel. Until fuel sulfur limits were mandated, the fuel’s lubricity was generally believed to be a function of fuel viscosity.
The process that is most commonly used to remove sulfur from fuel is called
of sulfur. Crude oils with low sulfur require little
The
All low sulfur fuels do not have a low lubricity. The fuel’s lubricity may be enhanced with additives. Many fuel suppliers treat the fuel with these additives. Do not use a fuel lubricity additive before you consult the fuel’s supplier. Some aftermarket additives may not be compatible with the additives that are already in the fuel. Some additive packages that are supplied by the aftermarket manufacturer may not be compatible with the seals that are used in fuel systems of some diesel engines. Other additive packages that are supplied by aftermarket manufacturers cannot provide proper performance in high temperature conditions. These additives may leave deposits because of the high temperatures that exist in the fuel systems of diesel engines.
Maximum life of the fuel system can be achieved by performing the following tasks: using a reliable fuel supplier, performing proper maintenance of the fuel system, and installing Caterpillar high efficiency fuel filters in the fuel system.
Note: Lighter fuels are frequently used in arctic temperatures. Lighter fuels may include the following fuels: Jet
Viscosity
The viscosity of the fuel is significant because the fuel serves as a lubricant for fuel system components. Arctic fuels need to have sufficient viscosity. The fuel must lubricate the fuel system at a temperature of 0C (32F) or below freezing. If the kinematic viscosity of the fuel is lower than 1.4 cSt as supplied to the fuel injection pump or to the unit injectors, excessive scuffing and seizure can occur.