ignition delay

Fuels with higher cetane number have shorter ignition delays, providing more time for the fuel combustion process to be completed.

The fuel's derived cetane number can then be calculated using an empirical inverse relationship to ignition delay.

In a particular diesel engine, higher cetane fuels will have shorter ignition delay periods than lower cetane fuels.

The ignition delay of the fuel can then be calculated as the time difference between the start of fuel injection and the start of combustion.

In particular, the panel warned that the hydrazine fuel for the lander's retrorockets might freeze in space, producing ignition delays, irregular pulses and possibly leading to a topsy-turvy landing.

Cetane number or CN is a measure of a fuel's ignition delay, the time period between the start of injection and the first identifiable pressure increase during combustion of the fuel.

This weakness may be eliminated by designs where the fuel is preheated well above its ignition temperature, so that its cooling during its dispersion still results in a minimal ignition delay on mixing.

Requirements for fuels to be used in diesel engines are the ability of the fuel to flow along the fuel lines, the ability of the fuel to lubricate the injector pump and injectors adequately, and its ignition qualities (ignition delay, cetane number).

When used in highly supercharged diesel engines with the corresponding low compression ratio of about only 14:1 or below, JP-8 causes troubles during cold start and idling due to low compression temperatures and following ignition delay because cetane index is not specified in MIL-DTL-83133G to 40 or higher.