Crude Oil
The term crude oil is used to describe petroleum-based oils/fuels that are not yet refined. They are essentially in the same state as when they were pumped from the earth.
Certain types of crude oils can be burned in Cat engines. In some cases, crude oil is a practical and economical fuel for diesel engines. Crude oils are evaluated individually and special equipment may be needed to condition the fuel. Minimum guidelines have been established to determine the suitability of crude oils as shown in Appendix 2.
Residual Oil or Blended Heavy Fuel
Oil (HFO)
Residual fuel (which resembles tar and contains abrasive and corrosive substances) is composed of the remaining elements from crude oil after the crude has been refined into diesel fuel, gasoline, or lubricating oil.
After the more desirable products have been refined, residual fuel can be combined or diluted with a lighter fuel to produce a mixture that can flow. This mixture is called blended or heavy fuel. Heavy fuels tend to create more combustion chamber deposit formations which can cause
increased cylinder and ring wear.
Blending may improve fuel density; however, adding alcohol (ethanol, methanol) or gasoline causes an explosive atmosphere in the tank and is not recommended. Cat 3600/C280 diesel engines, in general EPG applications only, can be modified to run on blended fuels, but extreme PREVENTIVE MEASURES MUST BE TAKEN, including following a thorough maintenance program and use of high quality fuel treatment equipment. For any other applications including marine, petroleum, industrial, etc. that require the burning of blended fuels, MAK Engines should be considered.
Blended fuel can lower fuel cost, but there are often significant trade-offs. Fuel price must be weighed against the following.
Fuel containment effects
Reduced engine component life
Higher maintenance and personnel costs
Reduced warranty
Distillate Fuel
Distillate fuels are refined from crude oil and are commonly referred to as diesel fuel, furnace oil, gas oil, or kerosene.
Marine Diesel Oil
Many different names are used for marine diesel fuels, which can often cause a misunderstanding. Four types of marine diesel fuel are generally recognized and available at bunkering ports around the world. However, not all of the types are available at every station.
Gas Oil
This is a light distillate fuel which does not contain any residual fuel. Gas oil is approximately ASTM No. 1 diesel fuel.
Marine Diesel
This is a distillate fuel that boils at a higher temperature than gas oil. The fuel varies from ASTM No. 2 diesel fuel to ASTM No. 4 diesel fuel. The composition can vary within the following range: ASTM No. 2 diesel fuel, No. 2 that is contaminated with heavier fuel in the bottom of the tanker, and No. 2 that is blended with as much as 20 % residual fuel.
Blended Fuel Oil
This is a blend of distillate and residual fuel. This fuel is blended to the viscosity that is requested by the operator or the engine manufacturer. Blended fuel is not recommended for use in Cat engines that are configured to use distillate fuel.
Residual Fuel
This is residue from the distillation of crude oil in a refinery. DO NOT use residual fuel in Cat engines that are configured to use distillate fuel.
Aircraft Jet Fuels and Kerosene Type Fuels
Aircraft jet fuels and kerosene type fuels may be used as a diesel engine fuel provided they meet acceptable limits. Adequate viscosity, particularly with kerosene type fuels is a major concern. For Cat engine fuel systems, a minimum viscosity of 1.4 cSt at 38ยฐC (100ยฐF) is required at the engine transfer pump to properly lubricate fuel system components. Kerosene type fuels
have lower energy content than diesel fuels and therefore will produce less peak power output and/or will require more fuel volume to do an equivalent amount of work.
Biodiesel
Biodiesel is a fuel that can be made from a variety of sources. Soybean oil and rapeseed oil are the primary sources, but alternate base stocks may include animal tallow, waste cooking oil, or a variety of other feedstocks.
In original forms, these oils are not suitable for use as a fuel in compression engines; they must first be esterified. Without esterification, these oils will gel in the crankcase and the fuel tank.
Ultra Low Sulfur Diesel (ULSD)
Ultra low sulfur diesel represents distillate fuels with โค15 ppm sulfur. It has been developed to reduce particulate engine emissions.