SeanR

I'm looking for the specs for the internals components of the MAF electronics. I know the pin outs and how the mechanics work but would like to know the graphical interaction between flow and resistance, resistors etc are mapped. How it is calibrated etc. I'm not looking to rebuild them but want to get a dang good idea how it works internally in relation to real time data.

SeanR

Oh we got some funny guys here LOL, thanks for the PM's.

the flyin' scotsman

Hot wires, rushing air, resistance changes, fluctuating voltages, output translation, all combined with various other sensorary input resulting in a signal transmitted to the injectors timed to throw some fuel into the combustion chamber at the same time piston is nearing TDC, valves are closed and the same time spark plug fires.

Time seems to be a common factor suggesting that an Oven Controlled Crystal Oscillator (OCXO) could be utilized to further enhance the alogorithmic metric.

Hope this helps

dr bob

MAF operation doesn't look at the changing resistance of the wire. Instead, the wire is heated to a certain temperature, temperature measured by a thermistor. The amount of current needed to maintain wire temperature is what changes as changes in mass air flow affect how much heat is carried from the wire. So the resistance of the wire is critical, as is the thermistor welded to the wire.

Speedtoys

..and IIRC, as cleaning cycles physically degrade the wire, the resistance changes..and that feedback loop works just fine, but you end up sending back erroneous results.

PorKen

AO

You could build your own test bed with one of these...

John Speake

As Ken has shown, the output voltage is measured from a varying current/vs air mass flowing through the sensor assembly. Uses a bridge circuit to give a compensated output.

Output is volts versus kg per sec air mass.

The response time of the MAF to changes of airflow is very fast, 1-3mS.