Quick answer
A high cetane number ensures diesel ignites more rapidly, reducing engine knock, noise, and pollutant emissions. It’s key for smooth, efficient operation.
Detailed answer
In a diesel engine, compression creates the heat needed to ignite the fuel. If the fuel ignites quickly (high cetane), combustion is cleaner and quieter. This reduces knocking, black smoke, and potential engine damage over time. Better ignition quality can also ease cold starts and cut back on harmful emissions. In countries where diesel is common, regulations often require a minimum cetane value—typically around 51—to balance performance and air quality. Drivers who use diesel with higher cetane may experience smoother acceleration, fewer rattles, and potentially minor gains in efficiency. All told, cetane number is a linchpin of diesel fuel quality.
