By the position of the butterfly.  When you lift your foot off the gas, the
valve closes and the air flow cuts to near zero.

Karl Wolz

----- Original Message -----
From: Jeff Nelson <ramjeff@EARTHLINK.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Tuesday, November 02, 1999 10:08 PM
Subject: AFM ?

> I was looking through a Bosch FI book today and noticed a statement
> saying that the ECU calculates the amount of fuel to inject by sensing
> the RPM and load on the engine.  I know the various sensors, throttle
> switch, etc. etc. are in there too...but the RPM and load seem to be the
> main inputs during steady driving.
>
> I also read that the engine load is mainly determined by the AFM, i.e.
> how much air is being drawn in.  How does this work???  It seems to me
> that the amount of air into the engine would simply be the displacement
> X RPM. How does the engine load affect the amount of air it consumes at
> any given RPM?
>
> Thanks,
>
> JN