Custom MAF system: help w/ calculations

[John Dammeyer]

Hi,

My guess is the MAF systems still use some sort of Volumetric Efficiency
table or else you could use a percentage of intake valve open time since you
already have the flow rate.  If you work it backwards you can see that
sampling the MAF rapidly over the period of time that the intake is open
will give you a series of mass air readings that summed probably come close
to the mass of air in the cylinder.

Cheers,

John

----- Original Message -----
From: <james.drysdale at utoronto.ca>
To: <diy_efi at diy-efi.org>
Sent: Tuesday, January 23, 2001 5:14 PM
Subject: Re: Custom MAF system: help w/ calculations


>
> > Good luck with your endeavor.  Welcome here.  I won't say much about
> > UofT, other than to say I hail from Queen's, 'nuff said :)......
>
> Queens...was my second choice. Really. :)
>
> In regards to your post, I'll get a little more specific: I know from the
MAF
> the amount of air entering the engine (in kg/s)...but what time value do I
use
> to calculate the amount of air actually entering the engine, so I know how
much
> fuel to add to it? Is it the duration of an intake cycle?
>
> air_mass_into_engine (kg) = flow_rate_of_air (kg/s) * time(?) (s)
>
> fuel_to_add = air_mass (kg) / 14.7
>
> injector_pulse_width = injector_flow_rate (kg/s) / fuel_to_add (kg)
>
> (These are simplified versions of the equations that don't take into
account
> injector opening times, enrichments, etc.)
>
> I'm searching through the archives to see if this has been discussed
before
> (yikes...50 megs of text files!) but I'd still appreciate any input.
>
>
> Thanks,
>
> james
> --------------------------------------------------------------------------
--
> To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the
quotes)
> in the body of a message (not the subject) to majordomo at lists.diy-efi.org
>
>
>

----------------------------------------------------------------------------
To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org