Re: Load (not)

["Ken Cory" <kcory@xxxxxxxxxxxx>]

Well, it feels like someone needs to make a record that Jim C.'s masterful
analysis is appreciated by the reader, even if it makes Bobo's head hurt.  I
don't mean that I understand all of it (I've often been a screwdriver and
ear man too), just that it really helps sometimes to get the absolute real
explanation, and Jim C. clearly has a handle on that.  Thanks, Jim
Ken Cory
kencory@domain.elided

- ----- Original Message -----
From: "Jeff Lloyd" <Jeff@domain.elided>
To: "Jim Conforti" <lndshrk@domain.elided>; <944@domain.elided>
Cc: <bmw-digest@domain.elided>
Sent: Tuesday, November 07, 2000 2:49 PM
Subject: RE: Load (not)


| Ugg.. Long words make Bobo Brain Hurt...
|
| All Bobo know how to turn round thing and press loud pedal
|
| Bobo like big metal thingy on top of engine and Wire thingy
| Bobo can turn wire thingy and motor make pretty
| Or ugly sound Bobo says computer evil
|
| Bobo needs screwdriver, not computer
|
| Bobo
| (BOBO for president in '04)
| Brought to you by (friends for Bobo and the National Carburetor
Association)
|
|
| (argh back to work)
|
|
| -----Original Message-----
| From: owner-bmw@domain.elided [mailto:owner-bmw@domain.elided]On Behalf Of Jim
| Conforti
| Sent: Tuesday, November 07, 2000 1:26 PM
| To: 944@domain.elided
| Cc: bmw-digest@domain.elided
| Subject: Load (not)
|
| Unfortunately, you've fallen victim to the disinformation.
|
| The "barn door" aka Vane AFM does NOT "max out" at 3-4000 rpm.
|
| All of this complete BS about Motronic comes directly from
| father Bosch who apparently allowed some writer to copy sections
| verbatim from the L-Jet Manual over to the Motronic Manual.
|
| (bad, BAD plagiarist!)
|
| In Motronic, if your air meter (be it Vane AFM or HFM/etc) maxes
| out inside the operating range, you are hosed good.
|
| Motronic needs exactly three things to calculate LOAD.
|
| 1) A signal from the air meter, normalized to "Q" airflow in kg/hr
|
| 2) A measure of current engine rpm "n"
|
| 3) A programmed injector size constant "Ki" (K sub eye)
|
| LOAD aka Tl (Tee sub ell) is calculated as:
|
|   Tl = Q / (n * Ki)
|
| LOAD is not just a representation of cylinder filling, but the
| theoretical Injector Time Open (Ti, Tee sub eye) needed to reach
| stoich (Lambda= 1) with the current injector setup assuming that
| the motor is "perfect".
|
| Which it isn't, hence there are fueling tables which are used as
| multiplicative corrections to LOAD to reach the actual Ti.
|
| Hope this clarifies.
|
| Jim Conforti
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