Pre/post ignition

[Danny Barrett]

As I understand, the most volitile constituents of the fuel are the smaller
molecules, such as methane which has an octane number of about 116. To me,
this would indicate that the volitiles are the least likely to pre-ignite.
The problem which I can see is that pre-ignition causes excess turbulence in
the gases in the cylinder, and this (along with the fact that peak cylinder
pressure occurs too early) decreases both the power, and the efficiency (or
so my Thermodynamics textbook says).

Danny Barrett.


>As I recall from a Texaco Research Film (?) from the early 70's,
>in a series of variable compression engines they were able to
>generate a pre-ignition event at 5-7d pre ignition.  
>  If someone has something more current/up to date, I'd like to
>hear it, cause the neural net involved with this is an old set.....
>  Just to stir things up,  wouldn't the most viotile stuff react first,
>leaving little or nothing combustable, for a post event?.  
>  Cheers
>Bruce