Flywheel/Encoder patterns

[Mazda Ebrahimi]

Kalle Pihlajasaari wrote:
> 
> Hi There,
> 
> > An encoder giving absolute crank position would implicitly supply an
> > interrupt when the position changes value. Reading crank position directly
> > means you wouldn't have to fool with timers or counters to derive it. You'd
> > also know exactly what the position is upon start-up without having to store
> > the last known position info upon shutdown. No way around the cam sensor tho
> > that I can see.
> 
> I still have not figured out why one could not replace the distributor
> with a 512 line Grey/binary encoder with 9 bits of absolute crank position.
> 
> Make a backlash free coupling to the shaft and perhaps preload the
> shaft in the engine as well.
> 
> Absolute position to 1.4deg on the crank (0.7 on the cam shaft)
> 
> Cheers     *<<<-|
> --
> Kalle Pihlajasaari   kalle at ip.co.za   http://www.ip.co.za/ip
> Interface Products   P O Box 15775, DOORNFONTEIN, 2028, South Africa
> + 27 (11) 402-7750   Fax: 402-7751    http://www.ip.co.za/people/kalle

I might be wrong, but 1.4 degrees is alot of variation, especially for 
ignition timing.  That's one of the reasons alot of newer designs have 
gone away from traditional distributors.  Even the ones that have 
distributors, still use a crank signal for timing purposes and just use 
the distributor to distribute the spark.