AFM measurement/backpressure

[Mike (Perth, Western Australia)]

At 10:34 AM 12/3/2000 +0800, Bernd Felsche <bernie at perth.dialix.com.au> wrote:

>>The resistance of the wire varies with its temperature, so one approach
>>would be to measure the voltage required to hold the wire at a constant
>>current. The more air flow you have at a given IAT, the cooler the wire
>>gets.
>
>The current flow is directly related to the *mass* of the air
>flowing in. That is generally sufficient to determine the amount of
>fuel to inject.
>
>If you however desire air temperature - e.g. to adjust spark timing
>or to alter the injection to allow for vapourization in cold air,
>then you must sense this separately.

Most hot wire AFM's I've seen include an air temp sensor but its wired
into the wheatstone bridge which has the wire, on my Bosch AFM - its a
little vertical tongue in the middle of the circular hot wire assembly,
trouble is its not available as a separate signal to the ECU - just
adjusts the AFM output signal appropriately.

A separate one would be of some use - but with the performance level of
my engine at moment its of marginal benefit...



Rgds


Mike Massen

Ancient Sufi saying:
        "Should your God save you from adversity, choose another God"

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