16 x 16 lookup tables

Jonathan R. Lusky lusky at knuth.mtsu.edu
Thu Jun 30 01:37:31 GMT 1994


Ciciora Steve writes:
> Does anyone have any comments/suggestions to the above?  Am I on the right
> track?

I'm not familiar with the details of interpolation, so I can't comment
on that.  However I do believe that an 8x8 map is very inadequate.
16x16 plus interpolation is what my EFI Techinologies ECU used.

> In thinking about how a carb works, I would need a 'Modifier' for the EFI
> equivilent of a choke on a carb (works off coolent temp?) and a modifier for
> the accelerator pump (works off the rate at which the gas petal is being
> pressed down).  Besides for a ignition curve, what else would I need a lookup
> table for?

Okay, here are the curves that the EFI Technologies ECU I had used:

Fuel (16x16)
Spark (16x16)
Temperature Sensor Linearization
Injector Correction f(Throttle)
Battary Offset Correction f(Battery Voltage)
Transient Multiplier f(Watertemp)
Injection Correction f(Air Temp)
Injection Correction f(Water Temp)
Spark Correction f(Air Temp)
Spark Correction f(Water Temp)
Injector phasing f(RPM)

Except for the first three and the last one, all of those are multiplier
tables.  By that I mean the pulse width from the first two tables is 
multiplied by the value in the table for the given condition.  In our
setup, several of those curves were straight lines at 1 :).

Acceleration encrishment uses a constant multiplier and a constant decay
rate.  There is also a minimum throttle position threshold for
acceleration enrichment and a throttle position point for acceleration
enrichment saturation.  I believe accelration enrichment is scaled
linearly between those two points (as a function of throttle position
of course).

Does this help any?


-- 
Jonathan R. Lusky  --  lusky at knuth.mtsu.edu
 "Turbos are nice but I'd rather be blown!"
    68 Camaro Convertible - 350 / TH350
       80 Toyota Celica - 20R / 5spd



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