Mass flow sensor qn..

[Craig Pugsley]

Hi,

In a local electonics magazine called 'Electronics Australia', there is
a collumn on automotive electronics.

In the most recent issue he had a cro trace of an 'Air mass meter'
output with the engine accelerating from idle to high speed in 0.9sec.

As you might expect, the output voltage increaed with time, HOWEVER,
there was significant 'pulsation' (about 20-30 % of the full scale reading)
in the output. Obviously at low RPM you would expect this to occur, but it was
ALSO occuring at higher RPM.

He posed the question to readers as to why this might happen (he didn't
know). Could it be that the sensor is sensitive enough to detect the
intake stroke of each cylinder? Or maybe some resonance effect?

(He didn't say what sort of sensor it was - I wouldn't have though a trapdoor
or hot wire sensor would respond so quickly. Could an ultrasonic (Karmann)
sensor work this quickly?)

Craig.

PS is anyone familiar with the 'PIC' range of microcontrollers/'basic
stamps'? None of them seem to have and a/d inputs or outputs.