Glossary of Fuel Terminology – Diesel and Gasoline
Diesel Fuel
API Gravity: The American Petroleum Institute has created a density scale which is an inverse measure the relative density of petroleum products to that of water. Therefore, the lower the API gravity the more pounds per gallon.
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Typical API Gravity |
Pounds / Gallon |
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#2 Ultra Low Sulfur Diesel |
33 – 40 |
7.16 – 6.87 |
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#1 Ultra Low Sulfur Diesel |
35 – 45 |
7.08 – 6.68 |
ASTM: American Society for Testing and Materials; devoted to the standardization of methods of testing.
Biodiesel: An alternative diesel fuel made from vegetable or animal commodities, such as soybean oil and animal fat.
Cenex Premium Diesel Fuels: Are premium fuels blended to exceed the industry standards for high quality diesel. Diesel fuels that contain Cenex’s finely-tuned additive package, consisting of aggressive Detergents, Water Demulsifiers, Fuel Stabilizers, Corrosion Inhibitors, Lubricity Improvers and Cetane enhancers.
Demulsifier: An additive to reduce the amount of entrained water in the fuel.
FMXL: Dyed Ruby FieldMaster XL Premium Diesel Fuel
RMXL: Clear RoadMaster XL Premium Diesel Fuel
Seasonally Enhanced: Formulated for moderate climates and provides excellent shoulder season flexibility. Cenex Seasonally Enhanced products offer a CFPP of -25 °F.
Winter Aid IV: A cold flow improver with a Wax Anti-Settling Agents, used to extend the operability of the fuel.
WMXL: WinterMaster XL Premium Diesel Fuel with a typical CFPP of -55°F and an operability of -30°F.
CFI: Cold Flow Improvers are designed to extend the cold temperature operability of fuel by keeping wax crystals found in diesel fuels much smaller and acting as a dispersant to prevent crystals from grouping together, thereby allowing the fuel to flow unrestricted through fuel lines and filters as much as 15°F colder than the cloud point.
Cold Temperature Tests: Are a series of tests designed to determine the cold temperature operability of the fuel.
CFPP: Cold Filter Plugging Point is the lowest temperature in which fuel will pass through a standard test filter.
Cloud Point: The temperature at which wax crystals begin to appear in the fuel, forming a hazy appearance.
Cold Temperature Operability: The lowest temperature that a diesel fuel can function properly without cold weather performance issues.
Pour Point: The lowest temperature at which a petroleum product will pour or flow.
Color/Appearance: Physical appearance to identify a petroleum product.
Black: The sample has a dark discoloration, which is typically due to the presence of solid debris or oxidized fuel.
Dyed/cldy: The sample is dyed and has a cloudy appearance. This is typically due to water contamination.
Dyed/clr: The sample is dyed and has a clear appearance.
Derived Cetane Number: The measure of the ignition quality of a diesel fuel.
Distillation Range: The temperature range in which a petroleum product will boil.
IBP: Initial Boiling Point is the temperature at which the lightest fraction of fuel begins to boil.
FBP: Final Boiling Point is the temperature at which all of the volatile compounds of the fuel have evaporated.
Typical Distillation Temps |
Initial Boiling Point |
10 % |
50% |
90% |
Final Boiling Point |
|
Ultra Low Sulfur Diesel |
200 - 300 |
300 – 420 |
390 - 560 |
480 - 673 |
600 - 840 |
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Gasoline |
75 - 135 |
95 - 158 |
150 - 250 |
260 - 374 |
365 - 437 |
FBT: Filter Blocking Tendency test is used to determine the severity of flow restriction due to solid debris contamination.
Lubricity: A way of determining the ability of a fuel to resist wear. The lower the number the greater lubricity of the fuel.
µm @ 60C: The diameter of the wear scar is measured in microns (µm), at a temperature of 60 °C (140 °F).
Micron (µm): Is a unit of measure for distance, which is 1,000 times smaller than a millimeter. For example, human hair is typically 90 microns across.
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Lubricity Specifications |
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Regular #2 Ultra Low Sulfur Diesel |
520 Max |
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Cenex Premium ULSD Fuel |
460 Max |
Sulfur: Naturally occurring element found in crude oil considered a contaminant in finish fuel products. EPA regulates the concentration of sulfur allowed in fuels. For ULSD the maximum Sulfur concentration is 15 ppm.
ppm: Parts-per-million is one part Sulfur for every million parts diesel fuel.
Gasoline
Alcohol/Ethanol: is an alcohol based alternative fuel to gasoline that is produced from vegetable products like corn.
API Gravity: The American Petroleum Institute has created a density scale which is an inverse measure the relative density of petroleum products to that of water. Therefore, the lower the API gravity the more pounds per gallon.
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Typical API Gravity |
Pounds / Gallon |
|
Gasoline |
53 - 74 |
6.40 – 5.84 |
Distillation Range: The temperature range in which a petroleum product will boil.
EPA Volatility Class: EPA regulates the vapor pressure of gasoline to reduce emissions from that contribute to reduce the effects of ozone-related health problems.
IBP: Initial Boiling Point is the temperature at which the lightest fraction of fuel begins to boil.
FBP: Final Boiling Point is the temperature at which all of the volatile compounds of the fuel have evaporated.
|
Volatility Class |
Initial Boiling Point |
10% |
50% |
90% |
Final Boiling Point |
|
|
Summer Grade |
A |
75 – 135 |
95 – 158 |
170 – 250 |
260 – 374 |
365 – 437 |
|
|
B |
75 – 135 |
95 – 149 |
170 – 245 |
260 – 374 |
365 – 437 |
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|
C |
75 – 135 |
95 – 140 |
170 – 240 |
260 – 365 |
365 – 437 |
|
|
D |
75 – 135 |
95 – 131 |
150 – 235 |
260 – 365 |
365 – 437 |
|
Winter Grade |
E |
75 – 135 |
95 – 122 |
150 – 230 |
260 – 365 |
365 – 437 |
*Volatility is determined by location and season
Octane Number: A term numerically indicating the relative antiknock value of gasoline. The octane number of gasoline depends on its hydrocarbon composition, and is improved by adding an antiknock additive
RVP: Reid Vapor Pressure is the volatility of gasoline measured in psi. Higher RVP fuel is required for winter operation to ensure ease of ignition in cold temperatures, but too high of an RVP in summer may cause vapor lock in the fuel lines, preventing fuel from entering the combustion chamber.
psi: Pounds per Square Inch
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Volatility Class |
Regular Gasoline |
E10 Gasoline |
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|
Summer Grade |
A |
9.0 max |
10.0 max |
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B |
10.0 max |
11.0 max |
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C |
11.5 max |
11.5 max |
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D |
13.5 max |
13.5 max |
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Winter Grade |
E |
15.0 max |
15.0 max |
*Volatility is determined by location and season