DIY_EFI Digest V4 #616

[CSH-HQ]

Is this univerally true for the gm ecms?.
Grumpy
>
>Hi All,
>
>Here's a simple method of calculating the required extra fuel for
>sudden load
>changes that will appeal to the programmers amongst us.
>
>This supposes that you are running speed/density from a fuel table.
>
>The TPS reading is taken from the A/D and placed on a stack.
>This is done say 10 times every say 10 msec until a "history" of TPS
>is
>available.
>
>As soon as a new reading is placed on the stack you do a 1st minus
>last to give delta TPS. If the number is equal to the max. possible
>delta you inject 100% of the Variable AccEnr ms  adding it to the Full
>Load fuel ms for that RPM.
>
>If its say 40 counts you add 40% of the AccEnr to the next injection.
>Some ECU's calculate the proportion lost to some cylinders due to
>their position in the cycle and add that to the next injection after
>that. This is due to the fact that when ever you inject it is only
>half the fuel that is supplied per
>rev of the engine and some cylinders will only get 50% of the
>enrichment.
>
>This is also true if the result is negative you can subtract the
>inverse and avoid the over rich "puff" that you get when the throttle
>is closed suddenly
>
>As you can see we are assuming that as the throttle is translating
>rapidly the MAP sensor will be reading close to atms very "SOON" thus
>we are using throttle translation as a predictor of ultimate load.
>
>Now of course the algorithm for the decay of the AccEnr is something
>that you didn't ask about but suffice to say you could make it a
>variable based on the rate of change of RPM and the starting RPM and
>the current load. There is quite a difference between "stabbing "the
>throttle to change down a gear and flooring your Acc in gear.
>
>
> Phil
>Injec Racing