What is Cetane Number in diesel fuel?

Cetane Number (CN) is a measure that indicates the quality of diesel fuel and describes the level of cetane in the fuel. Coded C14 to C21, higher cetane number means the diesel fuel has better combustibility.

In other words, CN shows the ignition quality in the combustion chamber. Diesel fuel with higher CN also means that the fuel has better quality. With better combustion, engine runs more efficiently.

In Indonesia, the diesel fuel products marketed and sold are CN 48 and 51 as stipulated by the Decree of Oil and Gas Director General No. 3675 K/24/DJM/2006.

CN 48 and CN 51 corresponds to Euro I and Euro II where their maixmum sulphur content is maximum 3,500 ppm and 500 ppm, respectively. Sulphur content affects an engine’s emission level and the condition of common rail in modern diesel engines.

CN is the RON equivalent of gasoline. The higher value, the higher the quality of the diesel fuel.