[Diy_efi] Air/Fuel meter now working! And L-jetronic
amdcpu at hot.ee
Thu Jun 16 17:58:42 CDT 2005
----- Original Message -----
From: "Adam Wade" <espresso_doppio at yahoo.com>
To: <diy_efi at diy-efi.org>
Sent: Friday, June 17, 2005 1:34 AM
Subject: Re: [Diy_efi] Air/Fuel meter now working! And L-jetronic
> --- Astrona <amdcpu at hot.ee> wrote:
> > With NA engine and L-jet we also know only the flow
> > and not the real density.
> NA L-Jet applications have an AAP and an AAT sensor
> (sometimes the AAT sensor is inside the VAF), from
> which the ECU determines the density of the air.
Have you seen pressure sensor in L-Jets? I haven't heard!
> > But we can think so: when 0.5L air @2bar abs
> > pressure moves to cylinder, the same amount of air
> > needs to go through airflowmeter = 1L @ 1bar. It can
> > be a bit delayed.
> That is exactly my point. Those are the same air
> MASS, but the former will be seen as being only half
> the flow by the VAF. At that point, the mixture would
> become so lean that I would expect the vehicle to
> stall, UNLESS there is a way to "inform" the ECU of
> the density of air in the plenum.
Why only half???
> > At the same manifold pressure, temperature, throttle
> > position and RPM - we know the mass if we have
> > volumetric efficiency table (flow speed).
> L-Jet (not LH-Jet) has neither any tables (it's an
> analog ECU), nor has it a manifold pressure sensor
> (and neither does LH-Jet). Presumably there are what
> amount to VE tables for the LH-Jet, as it is a digital
> ECU, but I have not looked at an EPROM dump from one.
Although analog ECU's didn't have ROMs, they had maps.
Mapped by resistors. ;)
> > If added air flow (speed) meter, we could forget
> > these tables :D and put that system onto whatever
> > engine.
> Almost, but not quite, as cylinder filling is not
> always the same as what passes the MAF.
Yeah, with different cam for example, the same pressure in manifold will end
up different pressure in cylinder.
> > What WBO2-guys mean by AFM?
> Air-Fuel Meter.
It's not fear. :)
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