[Gmecm] BLM cell confusion
WopOnTour
wopontour
Mon Nov 14 04:50:48 UTC 2005
Wow
That just blows me away
I gotta take a closer look at that $1A calibration as it appears to break
all the rules that I thought I had somewhat straight in my head going back
over 20 years now.
Thanks for your insights
Regards
WopOnTour
----- Original Message -----
From: "Ryan Hess" <rgmecm at yahoo.com>
To: <gmecm at diy-efi.org>
Sent: Sunday, November 13, 2005 5:12 PM
Subject: Re: [Gmecm] BLM cell confusion
> Well according to Steve's previous post, it doesn't
> increment linearly, but rather is like a
> teeter-totter... The "plank" itself is always moving
> to the rich or lean (like the integrator trying to
> keep the engine stoich), and the pivot is moving to
> bring everything into a long term balance (the BLM to
> 128)
>
> It seems as though the increment of the BLM by one as
> the INT hits it's limits is common in most other
> applications (as you've seen with the 16 BLM cells),
> but I have to say that the $a1 is different. It's
> always trying to keep the int at 128 +/-4 (the INT
> "action" window). It also appears that the INT takes
> a much larger portion of the fueling equation.
>
> That's how I observe it, anyways...
>
> --- WopOnTour <wopontour at hotmail.com> wrote:
>
>> Well first you need to operate it so it's IN cell 2
>> (In gear with some RPM
>> above idle??)
>> In any cell, as integrator climbs small amounts of
>> injector pulse
>> width/delivery (bpw x 1.001?) are occurring. When
>> integrator hits it's high
>> clamp point (eg 138) it will increment BLM +1 and
>> reset integrator to 128.
>> This would result in an increase from the base
>> delivered fuel or base pulse
>> width x 1.01 This cycle will continue if the O2
>> feedback continues to show
>> leaner than stoich. So in your example if BLM in any
>> cell achieved 128+5
>> (133) when it finally achieved a stoich ratio this
>> would equate (depending
>> on calibration) to say bpw x 1.05 This value will
>> then remain "stored" in
>> this cell so that next time the vehicle is at the
>> same load (same cell) it
>> will commence immediately with a 1.05 factor. Of
>> course the opposite occurs
>> if O2 feedback is indicating RICHER than stoich.
>> Well that's the way I understand it anyway
>> Hope it helps
>> WopOnTour
>>
>> ----- Original Message -----
>> From: "Ryan Hess" <rgmecm at yahoo.com>
>> To: <gmecm at diy-efi.org>
>> Sent: Sunday, November 13, 2005 10:52 AM
>> Subject: Re: [Gmecm] BLM cell confusion
>>
>>
>> > Any other ideas about getting cell 2 to learn?
>> I'm
>> > really stumped here.
>> >
>> > Or - maybe you can explain the relationship
>> between
>> > INT and BLM? I think I read somewhere that one
>> INT
>> > step is 1/2 a BLM step? So could I say an INT of
>> 138
>> > would correspond to the current BLM + 5?
>> >
>> > Ryan
>> >
>> >
>> > --- Ryan Hess <rgmecm at yahoo.com> wrote:
>> >
>> >> That helps immensely, Gary, thanks!
>> >>
>> >> Since all the other conditions are being met,
>> I'll
>> >> just have to assume it's my BPW that isn't above
>> >> 1.08.
>> >> It's hard to tell when the ALDL data only puts
>> out
>> >> integers...
>> >>
>> >> But in starting to tune the main VE table, I
>> guess I
>> >> would want cell 2 'learn enabled' while I hold
>> the
>> >> engine at some specified RPM, and "anchor" the VE
>> >> table at that point with a BLM of 128 by changing
>> >> the
>> >> BPC vs EGR constant, then go open loop and start
>> >> tuning the VE via wideband.
>> >>
>> >> I guess the problem is in enabling block learn.
>> The
>> >> BPW you mentioned of 1.08 is in the low
>> hysteresis
>> >> constant... I don't understand hysteresis to
>> begin
>> >> with, but I assume if I changed it to 0.7, I
>> would
>> >> want to change the high hysteresis value to
>> around
>> >> 1...
>> >>
>> >> Ryan
>> >>
>> >>
>> >> --- Gary Evans <gary at garyandliz.com> wrote:
>> >>
>> >> > The $A1 code uses 3 BLM cells:
>> >> >
>> >> > Cell 0 = idle
>> >> > Cell 1 = part-throttle
>> >> > Cell 2 = "overrun" aka no load
>> >> >
>> >> > As you have discovered, cell 2 is entered on
>> the
>> >> > conditions of high
>> >> > (ish) RPM and low map, such as coasting with
>> the
>> >> > throttle closed. I'm
>> >> > not sure what the point of the cell is other
>> than
>> >> > for emissions
>> >> > purposes.
>> >> >
>> >> > From the ARUR bin, the vales required to enter
>> >> Cell
>> >> > 2 are:
>> >> >
>> >> > Map less than 32 kPa
>> >> > BPW less than 1.95 mSec
>> >> >
>> >> > There are also a number of conditions that must
>> be
>> >> > met for block
>> >> > learn to be enabled. MAP, BPW and RPM must all
>> be
>> >> in
>> >> > a certain range.
>> >> > For the ARUR bin, the conditions are:
>> >> >
>> >> > Closed loop conditions met (Coolant temp up,
>> >> engine
>> >> > run time met, no
>> >> > fault codes, o2 sensor ready)
>> >> > Charcoal canister not purging.
>> >> > RPM between 400 and 6375
>> >> > MAP above 22 kPa
>> >> > BPW above 1.08
>> >> >
>> >> > If you are just revving the car in neutral, it
>> is
>> >> > likely that one of
>> >> > the conditions is not being met. The time it
>> takes
>> >> > for the BLM to
>> >> > update is also dependent on how far the INT is
>> >> from
>> >> > 128. The table
>> >> > looks like this:
>> >> >
>> >> > ###########################################
>> >> > # F58 TABLE #
>> >> > # BLOCK LEARN DELAY TIME INTERVAL #
>> >> > # VS. DELTA BETWEEN INT AND 128 #
>> >> > # TABLE VALUE = SEC*20 #
>> >> > ###########################################
>> >> > 8997 52 82 F58A 4.1 SEC
>> >>
>> >> > 0 INT-DELTA
>> >> > 8998 4C 76 3.8 SEC
>> >>
>> >> > 2
>> >> > 8999 3C 60 3 SEC
>> >>
>> >> > 4
>> >> > 899A 32 50 2.5 SEC
>> >>
>> >> > 6
>> >> > 899B 2C 44 2.2 SEC
>> >>
>> >> > 8
>> >> > 899C 28 40 2 SEC
>> >> > 10
>> >> > 899D 24 36 1.8 SEC
>> >> > 12
>> >> > 899E 20 32 1.6 SEC
>> >> > 14
>> >> > 899F 1C 28 1.4 SEC
>> >> > 16
>> >> > 89A0 18 24 1.2 SEC
>> >> > 18
>> >> > 89A1 14 20 1 SEC
>> >> > 20
>> >> > 89A2 14 20 1 SEC
>> >> > 22
>> >> > 89A3 14 20 1 SEC
>> >> > 24
>> >> > 89A4 14 20 1 SEC
>> >> > 26
>> >> > 89A5 14 20 1 SEC
>> >> > 28
>> >> > 89A6 14 20 1 SEC
>> >> > 30
>> >> > 89A7 14 20 1 SEC
>> >> > 32
>> >> >
>> >> > So, a delta of 4 (INT at 124, for example) will
>> >> not
>> >> > start to move the
>> >> > BLM for at least 3 seconds.
>> >> >
>> >> > Each calibration will be a little different,
>> but
>> >> > that is the gist of
>> >> > it. With so few cells, the BLMs will naturally
>> >> vary
>> >> > with driving
>> >> > conditions. If it varies a lot then there is
>> room
>>
> === message truncated ===
>
>
>
>
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