KISS Fuel Injection via PIC. Any interest?

[Simon Bosworth]

I only plan on having two injectors.  Fitting 2 injectors to each intake looked like a
pain.

Cheers,
Simon


rhuish at goldrush.com wrote:

> > Hello all,
> > with all this sudden interest in PICs, I am wondering if anyone else
> > would be interested in a KISS (Keep It Simple Stupid) EFI based on a
> > 16C73 PIC ?  I am planning to do one for my 74 MGB.  The 'design
> > guidelines' would be:
> >
> Interesting project, I've been planning to replace the SUs' with a 2.2 TBI
> (67 MGB-GT), but the thought of separate injectors interest me.
>
> > - To replace SU HS4/HIF4 carbs, which are pretty minimalist pieces of
> > equipment.
> >
> Sounds right, I get real tired of the weekly "Oil the carbs"! I expect fuel
> economy would also benefit.
> >
> > - Batch fired injectors.  Software would work for any number of cyls.
> >
> I'd rather fire them in pairs. The minimal cost of additional components hopefully
> would be offset in reliability.
> >
> > - Inputs would be TPS, Coolant temp, MAF or MAP, Air Temp ? and RPM
> > signal picked off distributor.
> >
> > - Injector pulse width would be based on maps stored in EEPROM.
> > Possibly using byte-wide EPROM + some interface 'glue' chips to enable
> > the PIC to access 'external memory', which normally doesn't do.  If
> > processing time allows a serial EEPROM would make interfacing dead
> > simple.
> > - The chip includes a serial port to provide a handy 'user' interface.
> >
> > This should be quite a simple system hardware wise.  It could be
> > prototyped on a SIMSTICK type board, ($6 from Wirz electronics).
> > The batch fire method removes the need for special pick-up wheels and
> > sensors; there is no need for synchronisation.
> >
> >
> > Use Sandy's very nice injector driver board for low impedance
> > injectors.  High impedance types would be simpler.
> >
> > It should provide at least as good a performance as any analogue system
> > without any greater hardware complexity.
> >
> > Potential points against such a system are:
> > - Developing the fuel maps may be a problem, at least for the first
> > person to try it for a particular engine :-)
> > - You may still need some sort of I/O board to condition the input
> > signals.
> > - Would it really be that much simpler and/or cheaper than the EFI332
> > system? and would it divert resources away from the EFI332 project when
> > it really needs all the help it can get?
> >
> > Looking for feedback,
> > Simon
> >
>
> Bob Cuda-65 - Angels Camp, Calif.
> cudabob at workmail.com
> http://www.goldrush.com/~rhuish/



--
------------------------
Simon Bosworth
simonb at primenet.com