G090618 The difference between octane rating and cetane number or rating?

The difference between octane rating and cetane number or rating?

ocatne number or rating is the measure of the resistance of gasoline against improper combustion or pre detonation of the engine(knocking ,spark n pinging).it is measured relative to the mixture of iso octane (2,2,4 trimetyl pentane )and n-heptane .

while as cetane number or rating is the measure of combustion quality of diesel oil or it is the measure of the ignition delay.tthe higher the cetane number of diesel the lesser is the ignition delay and vice versa.