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