Cetane

The cetane number, or index, is an indicator of the combustion speed of diesel fuel and the compression needed for ignition. Diesel with a lower cetane number provokes ignition delays and requires more time to complete the combustion process. In short, higher cetane numbers indicate better ignition quality. Thus, diesel with a higher cetane number is preferred by engine makers as it influences the engine’s efficiency.

The cetane number in diesel also influences the concentration of carbon monoxide (CO) and particulate emissions from diesel engines. A Concawe’s study showed that for each one number increase in cetane number, there is about a 5% reduction of CO and particulate emissions.

According to SANS 341:2016 (part referring to Clean Fuel 1 requirements), the minimum cetane number