Accel enrichment

[Tony Bryant]

Why is accel enirchment (== throttle pump) needed? 

I'm talking about the momentary increase in required injector 
duration when the throttle is quickly opened, as opposed to constant 
running at WOT at that RPM.

For example a transition between from 15" vac to 0" (WOT) at say 2000 
RPM.

I'm trying to optimize this part of my algorithm, and I need to 
have some sort of understanding of what I'm trying to fix.

What is going on in terms of MAP, air flow velocity, pressure,
fuel vaporisation and VE?

What algorithm are in use, and what do they depend on?

Any help greatly appreciated.