Technician A says an 87 octane fuel is a blend of 87 percent octane and 13 percent ethanol. Technician B says an 87 octane fuel will experience detonation in a test engine at the same temperatures and pressures as a sample fuel blend of 87 percent isooctane and 13 percent heptane. Who is correct?

Question

Quizplus · Accepted Answer

Octane rating is a measure of a fuel's ability to resist knocking or pinging during combustion, not a percentage of octane in the fuel. An 87 octane fuel behaves like a blend of 87% isooctane and 13% heptane in terms of detonation resistance, as Technician B states.

Technician a Says an 87 Octane Fuel Is a Blend