Water injection?

[Eric Fahlgren]

Robert Wimmer wrote:
> 
> Will injecting a water/methanol mixture up-stream of hot-wire mass air
> sensor damage it or create erroneous readings?

I don't know about damage, but it seems to me that it doesn't
matter where you inject water as long as the MAF sensor has the
temperature sensor in the same place as the flow sensor.  If this
is the case, then you should get the same output from pre-sensor
with its smaller quantity of higher density charge, and from the
measurement of the hot-less dense charge produced by post-sensor
injection.

Of course if you are fully vaporizing the liquid before the sensor,
then this changes the O2 content of the charge and thus the mass
measurement has a different meaning than with just "pure" air.
I'd conclude from this that you want to inject after the MAF.

Note, if you are running an intercooled turbo system, you want
to inject after both the turbo and IC to get maximum cooling of
the charge.  I can explain why, but not until I've had a cup of
coffee this morning. :)

-- 
Eric Fahlgren                            Mechanical Dynamics, Inc
efahl at adams.com                          Ann Arbor, Michigan, USA
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