things are happening fast enough, that it doesn't matter 'too much ' that
each injector opening period isn't timed with the intake valve.
So sure, the fuel injected 'hangs out' for a few milliseconds before the
intake valve opens ......but it works well enough.
No modern engine uses anything this crude of course..........the standards
for  emissions , good drivability, power, and fuel economy have risen
dramatically since .....since say, the first waterboxer vanagon in 1983 and
a half.   We've come a long way from there baby .

In more evolved systems...........
called 'sequential electronic port injection', each injector is fired
individually, in time with each cylinder's intake stroke.
Cam and crank position sensors are needed for that .......
not that big a deal..........I was even dreaming of retrofitting a Subaru
fuel injection system to a waterboxer.
Vanagon fuel injection is pretty crude I think.,

the ECU on a waterboxer only knows two things about the basic engine (
besides coolant temp, AFM input,  and that sort of thing ) .....
it only knows that the engine IS turning ( from the distributor ) and what
the rpm is, but that's it.
Mas crude hombre !

Scott
www.turbovans.com

----- Original Message -----
From: "Allan Streib" <streib@CS.INDIANA.EDU>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Monday, April 06, 2009 6:50 PM
Subject: digifant injection

> Another post got me curious, and I read a bit about how Digifant works.
> From what I read it seems that all 4 injectors fire together, which
> confuses me -- I would have guessed that each injector fired just as the
> intake stroke was starting for that cylinder.  Does the fuel vapor just
> sort of accumulate behind the intake valve until the intake stroke for
> that cylinder?  Surely 3/4 of the injection cycles are not "wasted"
> fuel??
>
> Allan
> --
> 1991 Vanagon GL