Let's Talk ALGORITHMS

[Jim Conforti]

On Wed, 16 Aug 1995, Ennis Bragg wrote:

> 1)  What is meant by the Gas Constant of Air?

  R == the universal gas constant (tweaked for the mixed gas air)

  see any decent physics/chem bible ...

> 2)  How does one determine volumetric efficiency?

  Experimentally, generally Ve = f(MAP,rpm)

  It is then supposedly mappable to an EQUATION ... 

  i.e. no lookup table needed, all fits nicely in the eqn ...

  VE = K1(rpm)^2 + K2(rpm) + K3 +K4(MAP)

  As someone (sorry, forgot whom .. maybe mike?) pointed out earlier

> 3)  Once this equation is worked out, you have a good
>     starting point to derive a base pulse width, Right?
>     Now how do you factor in things like Throttle
>     Position Sensor, and Coolant Temperature Sensor?

  Once you know Mass Air Flow .. or Q ...

  (going to BOSCH mode ;)

  Load (Tl) = Q/(Ki*rpm)

  Where Load is the BASE FUEL INJECTOR PULSE WIDTH for stoich in ms.

  (This is the almighty secret of BOSCH Motronic :)

  and Ki is computed from the flow rate of injectors to make the injection
  quantity per 2 revs (per cycle) perfectly stoich. in a perfect world 

  From there ...

  Ti = (Tl * magic factors) + BVolt correction

  The REAL injection time is based on ideal multiplied by the various
  enriching and enleaning factors (like accel, decel, eng temp, etc)
  and then lastly we add the Batt. Volt. correction for slower injection
  opening at lower voltages ..

  Jim Conforti