Question 267Motor Plants - Assistant Engineer

You are correct, the statement "Ignition lag is reduced with fuels having a high cetane number" is the true statement concerning the cetane number of diesel fuel. The cetane number is a measure of the fuel's ignition quality, with higher cetane numbers indicating better ignition properties. Fuels with higher cetane numbers have shorter ignition delays, meaning the time between fuel injection and the start of combustion is reduced. This shorter ignition lag allows for more efficient combustion and better engine performance. The other options are incorrect because: A) the cetane number does not affect the amount of injection lag, which is determined by the fuel injection system design; B) the cetane number is not an indication of fuel viscosity, which is a separate fuel property; and D) the cetane number is in fact very significant in the diesel combustion process, as it determines the fuel's ignition characteristics.