crankshaft/flywheel encoder patterns

[kleenair at ix.netcom.com]

Mark Eidson wrote:
> 
> This is the same approach I have come up with but I'm only in the thought
> process.  Are you going to sequence your counters so that each cylinder will
> have a programmable injection timing?  This will also work for ignition.  I
> thought a phase locked loop running at a higher frequency would give more
> accuracy than 1 degree of cam rotation but can't figure out an easy to get
> the dynamic range required.  me
> ***************************************************************************
> * Mark Eidson                        Voice: (602)752-6513                 *
> * Staff Design Engineer                Fax: (602)752-6000              

Hi Mark,

Yes, I plan to sequence them, and I'm using the same approach for 
ignition coils.  Also, with one edge per crank degree, we can narrow our 
resolution to 0.5 degrees of cam rotation not 1 degree, and for my 
purposes this is accurate.  I know there are systems out there that claim 
they are more accurate, but I don't know beyound 1/2 degree if it makes a 
difference.

The reason I decided to go this route was to relieve the processor from 
too many interrupts.  I plan to set the processor up to be interrupted on 
every rising edge of the crank sensor (once every 2 degrees of crank 
rot).  When there is a rising edge on the CAM, I'll set angle to zero, 
and increment by two on every crank interrupt.  I then reload the 
counters (by writing to a memory location), when their proper angle comes 
up.

I'd like to discuss this more, but I'm out of time right now.  Write me 
back on what you think.