MAP map or MAF map

[Garrett McWilliams]

Steve wrote:
>The upstream temp sensor in the hot wire sensor isn't there to measure
>the actual temperature of the incoming air but to determine the change
>in temperature between the heating element and the detection element.
>A simplified mass flow meter would consist of two sensors, one upstream
>and one downstream of the heating element. You would expect the down
>stream element to be warmer than the upstream one because of the (heat
>carrying) mass going in that direction. 
>So the difference in heating at the sensor is proportional to the mass
>flow rate.
>


I had thought the MAF sensor measured how much current it took to keep
the heated wire at a constant temperature, i.e. more air going through cools
it off more -> more current to maintain temp of the wire.  Is this also used
or am I way off base?

Garrett McWilliams