EFI--Bosch Motronic

[Land Shark]

At 11:18 AM 7/15/96 -0500, you wrote:
>Land Shark <lndshrk at xmission.com>You wrote:  in regard to the Bosch Motronic
>system.
>
>
> It MEASURES air .. calculates LOAD from AIR and RPM and a constant (based
> upon injector size) then corrects for operation conditions (maps)
> to yeild injector PW ..
>
>
>So, let me see if I've got this straight. 

 Close .. but forget the GAS LAWS those are for MAP sensor systems..

>1. Sensory information (air volume, engine speed) is taken in by the controller
>
>2. Computations based on known, constant, well-established relationships
>like gas laws and whatnot  are performed to come up with a pretty good idea
>about         fuel demand, and relates that demand figure to injector gph
>flow rating.  Presumably this yields a duty cycle number that is used for
>the next step.

 Computation is done to calculate the base pulse width .. it is a theoretical
 pulse width for lambda=1 with the injector size and a VE of 1 figured in ..

>3. Then other sensory information (engine temp, air temp, throttle position?
>manifold air pressure etc.) is used to search the lookup tables for the
>appropriate             injector PW.These lookups are created through
>empirical work on the dyno or on the track. -[are there computations made
>here too?]

 No, the other sensory info, and the LOAD value and the RPM value calc'd above
 are used to find CORRECTIONS to the calculated base pulse width ..

 Mathematically it goes like this ..

 Q=f(Vafm)

 Tl = Q/(n*Ki)   LOAD, air per cycle, expressed as a time duration of the injectors

 Ti = (Tl*a*b*c...)+z (where a,b,c are the multaplicative corrections to make
                       the fueling proper, and z is the additive corr. for batt
                       voltage effects on the linearity of the injectors)

 Ti is what we open the injectors for .. Time fur Injection

 Hope this helps...

 Jim