on the definition of Start in shell autoignition
 

Hi all,

I found this in starcd users guide:

Start, End â€" Ignition starting and ï¬�nishing time or time step no., depending on the When? menu setting. Use a realistic value, e.g. the start of ignition, for the Start time but set the Finish time to a large number, so that ignition cut-off may be controlled solely by the limiting values speciï¬�ed above.

I can quite understand the realistic value of start of ingnition for spark ignition. But how do we define the ignition start of a compression ignition case then?

Mepgzzi