Th resistance of the wire is determined by its temperature, so the
information is equivalent, however you want to express it.

On Sat, Jul 5, 2014 at 4:42 PM, SDF ( aka ;jim lahey' - Scott ) <
scottdaniel@turbovans.com> wrote:

> the ecu doesn't read the temperature of the wires in the MAF sensor.
> it reads the change of resistance that occurs as more or less air flows
> over the wires.  The ecu is sending a small current through the wires.
> ( and a 'burn off' cycle is a common strategy )
>
> There are some MAJOR advantages of a MAF Sensor over an Air Flow Meter.
>
> - no moving parts ( ! ! ) no contacts to get dodgey or worn either
> - changes in humidity and barometric pressure are recognized by the ecu
> by how the Resistance of the wires change. Very 'smart' that way.
>
> I gather there have been attempts to make a MAF sensor for Digifant
> waterboxer fuel systems, without success.
>
> Scott
>
>
> On 7/5/2014 9:15 AM, David Beierl wrote:
>
>> At 02:16 PM 7/5/2014, Neil N wrote:
>>
>>> usually clean it when I replace the air filter. David's comment below
>>> makes me think that "yes", it burns off any oil during use. There is a
>>> protective mesh on this MAF.
>>>
>>
>> The one that I read up on long ago would heat the filament to at
>> least red hot, possibly white hot for a short time at some point in
>> either startup or shutdown cycle, possibly both.  Being platinum it
>> was much more resistant to that sort of insult than to anything
>> touching it.
>>
>> In use it would maintain the wire at a specific temperature and
>> monitor how much current was required at that moment to do so. That
>> would allow calculation of how much heat the wire was losing to the
>> flowing air and thus what mass of air was contacting the wire in each
>> measurement cycle.  And finally from that the mass flowing through
>> the intake.  I think maybe they kept the wire hot enough that
>> differences in intake air temperature were swamped - just short of
>> glowing tickles the back of my mind somehow.  What I'm not sure I
>> understood at the time and certainly don't remember now was how they
>> measured the temperature of the wire so they could control it.  I
>> have a bit of a feeling that it was something diabolically clever
>> that I thought would have to conflict with what else they were doing
>> with the wire,
>>
>> The wire needs unobstructed airflow (and hence heat transfer) on its
>> surface and because it's so thin very small particles on the surface
>> can have considerable effect.  I think it really has to run squeaky
>> clean all the time.
>>
>> Yrs,
>> d
>>
>>