Some simple facts about Cetane ratings on diesel fuel

Cetane ratings.

Diesel fuel has a cetane number or CN which is a measurement of the combustion quality of diesel fuel during compression ignition. The CN number is a important expression of diesel fuel quality among a number of other measurements.

The centane number is a measurement of a fuel's ignition delay, the time period between the start of injection and the start of combustion or ignition of fuel.

Generally, higher cetane fuels have shorter ignition delay periods that lower cetane fuels.

Most diesels run well with a CN from 40 to 55. Fuel with a high cetane number, with shorter ignition delays, provide more time for the fuel combustion process to be completed. Therefore, higher speed diesels operate more effectively with higher cetane number fuels.

There seems to be now performance or emmision advantage when CN is raised past 55. After this point, the fuel's performance hits a plateau.

In North America, most diesel is found at the pump in 2 ranges: 40-46 for regular diesel, and 45-50 for premium. Premium diesel may have additives in to improve CN and lubricity, detergents to clean injectors and remove carbon deposits, water disperants, and other additives depanding on local or seasonal needs.

To learn more about how using fuel additives in your diesel may improve the efficiency of your equipment, click here to go to the Diesel Fuel Additive page.

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