Cetane Number
The cetane number relates to the auto ignition quality of diesel fuel. The rating applies to diesel fuel similar to octane rating for gasoline. A measure of how readily diesel fuel starts to burn (auto ignites) at a high compression temperature. Diesel fuel with a high cetane number auto ignites shortly after injection into the combustion chamber and has a short ignition delay time. Diesel fuel with a low cetane number resists auto-ignition and has a longer ignition delay time. A minimum cetane of 40 is required for a optimal driveability and performance.