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[robert joseph dingli]

Hi Craig et al.

> Please tell us more about your injection computer! It seems you are one
> of the first people on this mailing list to get something up and going.
> What processor are you using? 68HC11? 8051? What method are you using,
> speed density (MAP sensor based), or with an airflow sensor of some
> description (trapdoor, hot wire, karman vortex). Tell us a bit about your
> algorithms, as this is always a talking point here.

Our system is based on, you guessed it, a HC11.  I originally used an
E2 chip with 2K of EEPROM which was very convenient but the 2K became
restrictive and now are using an E9 with 12K (UV EPROM for testing and
OTPROM for production).  The beauty of both versions is that they come
with a security option which is very important for commercial applications.
The system uses the traditional Bosch style speed-density lookup table
approach which is clearly described in their little red electronics
handbook.  I use manifold pressure as a load signal for most applications
that use intake plenums except rotaries which tend to have poor
vacuum signals.  Throttle position is used otherwise.  The system can
be switched between manifold pressure or throttle position based 
acceleration enrichment.

> I'm currently designing an ECU based on the 8051 family (80C552 to be
> precise), supposedly this chip was used in the bathurst skyline GTRs.
> My application is rotary turbos/peripheral ports so I plan on using
> speed-density, combined with throttle position for the peripheral ports
> (very little vacuum in a peri-port with more than about 1/4 throttle,
> and air flow sensors cost too much, unless I can make one). I have some
> measurements of an aftermarket ECUs performace if you're interested.

We've converted many a rotary including road reg RX2's,3's,4's and 7's,
rally cars, sport sedans, club racers, Super seven replicas, six ports,
brigdes ports, turbos etc.  A current project is a triple rotor 20B
twin turbo going into a heavily modified 323 drag car.  450 HP and 600 kg
should be a lethal combination.

I'd appreciate any info on available ECUs.

> Incidentally, has anyone else out there got a design to make a hot wire
> or karman vortex sensor? I wouldn't imagine hot wire would be overly
> difficult.

I wouldn't bother.  The last thing you would want to do is remake a part
that can be bought off the shelf.  Air mass flow measurement systems
have no benefit over speed-density systems except for OEM production
where the air mass flow sensor can compensate somewhat for production
tolerances.  They are expensive, fragile and require more complex
calibration.

> Cheers,
> Craig.

Robert

-- 
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             Robert Dingli           r.dingli at ee.mu.oz.au

Power and Control Systems                 Thermodynamics Research Lab
Electrical Engineering                    Mechanical Engineering
   (+613) 344 7966                           (+613) 344 6728
  University of Melbourne, Parkville, 3052, Victoria, AUSTRALIA
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