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.

Singapore’s diesel specification only set the minimum cetane number at 51 in 2017. Prior to that, there was no minimum limit set by the National Environment Agency.

SGS Worldwide Fuel Survey (WWFS) results from diesel samples taken from 2013-2023 showed that the average cetane number was above 51. In 2023, the average cetane number of diesel samples was 56.33, and the lo