[Gmecm] BLM cell confusion
Gary Evans
gary
Mon Nov 14 22:05:18 UTC 2005
Ah, ok, after reading Ryan's post, I see that the 16 cell code and
$a1/$88 code appear to handle INT quite differently. Interesting. I
will have to take a look at $8d and see how it works.
On Nov 14, 2005, at 1:41 PM, Gary Evans wrote:
> Small nit:
>
> The integrator does not need to reach the high clamp point to
> increment the BLM. If learning is enabled, any deviation of the INT
> more than 2 will begin to move the BLM after the specified wait
> time has bee reached. The further the INT deviates from 128, the
> sooner the BLM will update. See previous post on this subject.
>
> Also, the INT does not reset on a BLM value change... at least not
> on $88 or $a1
>
> Other than that, you are correct.
>
>
>
> On Nov 13, 2005, at 3:40 PM, WopOnTour 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
>>>> > for improvement in
>>>> > the tuning of your VE tables. In a perfect world,
>>>> > the VE tables would
>>>> > perfectly represent the exact airflow for every
>>>> > condition. In the
>>>> > real world it's never gonna happen, so don't spend
>>>> > too much time
>>>> > chasing "perfect" 128 values. Even filling your
>>>> car
>>>> > with a different
>>>> > grade of gas can throw the values by a few, so a
>>>> BLM
>>>> > of 124 is
>>>> > perfectly acceptable, nay, even excellent.
>>>> >
>>>> > If you do not have it already, I highly recommend
>>>> > getting ahold of
>>>> > the $a1 disassembly file and making an effort to
>>>> > understand the
>>>> > things the computer is looking for in its
>>>> operation.
>>>> > Even if you do
>>>> > not understand all the computer language stuff,
>>>> just
>>>> > looking at the
>>>> > tables and comments can be very enlightening.
>>>> >
>>>> >
>>>> > -Gary
>>>> >
>>>> >
>>>> > On Nov 10, 2005, at 8:07 PM, Ryan Hess wrote:
>>>> >
>>>> > > Yes, exactly. Entering cell 2 (by reving in
>>>> > neutral)
>>>> > > swings the INT to 137-ish, but the cell 2 BLM
>>>> > doesn't
>>>> > > change off 122. I don't know if learn enable
>>>> has
>>>> > some
>>>> > > kind of qualifier that I'm not meeting in
>>>> neutral
>>>> > > (MPH? MAP? BPW?) or what, but cell 2 appears to
>>>> be
>>>> > the
>>>> > > only one that doesn't move.
>>>> > >
>>>> > > An interesting side note is that my BLM data
>>>> > varies
>>>> > > widely depending on the driving that I do. But
>>>> -
>>>> > I
>>>> > > guess that's to be expected if the $a1 truly
>>>> does
>>>> > use
>>>> > > only 2 BLM cells (idle and off idle). I don't
>>>> > know
>>>> > > that it does. I can say that BLM cell 2 does
>>>> > appear
>>>> > > to be calculated from the cell 0 (idle) and cell
>>>> 1
>>>> > > (seems to be a changing TPS). I never see cell
>>>> 2
>>>> > > actually change, it only changes when you're in
>>>> > other
>>>> > > cells... "behind closed doors" so to speak.
>>>> > >
>>>> > > Now, from what I have seen in my data logs, it
>>>> > appears
>>>> > > as though the INT has to be off from 128 by 4
>>>>
>>> === message truncated ===
>>>
>>>
>>>
>>>
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