The quality of ignition in diesel fuel is assessed using which metrics?

The quality of ignition in diesel fuel is primarily assessed using the cetane rating, which measures the fuel's ignition quality. The cetane number indicates how quickly and efficiently the fuel will ignite when injected into the engine's combustion chamber. A higher cetane number generally leads to more complete combustion, reducing emissions and improving engine performance.

While octane ratings are critical in assessing gasoline fuels, they do not apply to diesel fuels. Instead, the cetane rating serves as the specific metric evaluating the ignition quality of diesel fuel. This is why the correct choice focuses solely on cetane rating and cetane number, which represent the essential criteria for determining diesel fuel's capacity for effective ignition. Other metrics such as fuel temperature and pressure, or viscosity and volatility, are not relevant to the ignition quality of diesel fuel in the same way that cetane numbers are.