[Diy_efi] RE More ECU progress

[Steven P. Donegan]

Ian is in fact keeping his eye on 2 stroke applications. He is the one
working on the crank trigger area which will likely be hardware (ie
CPLD/FPGA). At most I would expect potentially a single set of inputs to
that logic that would be jumper or software selectable (I prefer the
latter) to give the logic the profile of what it is trying to measure.

The ION power supply/current mirror/ADC design, while fairly 'simple' in
the electronics sense is only up to usage at the moment with a scope - I
do have quite a few ION documents and papers including what you provided
Adam and will likely spin the more sophisticated closed loop usage of
ION data to a separate group - hopefully one with far more impressive
math skills than myself :-) And I am extremely interested in exploring
the entire envelope of ION+wideband O2+ouija board for efficiency all
the way to maximum HP.

I will be making slight (if any are required) changes on the ECU design
to support greater temperature range components. The power supply for
that board already is about 2x hardened over what Megasquirt uses (or
any other auto based DC supply I've seen to date). The preliminary
design data should be available on the web site after the coming weekend
assuming I have some time to work on it. Sometimes that daily job just
intrudes too much on hobbies :-)

On Wed, 2007-02-28 at 01:56 -0800, Adam Wade wrote:
> --- Ian Molton <spyro at f2s.com> wrote:
> 
> > It will take CAS and cam angle inputs, and use them
> > to compute the crank angle to better than one
> > degree. how much better will depend on how good 
> > our interpolation algorithms work).
> 
> One thing to keep in mind if we want to get the rotary
> engine crowd.  No cam, rotors have 3 "combustion
> chambers" per, and they rotate at 1/3 "crank"
> (actually called an eccentric shaft) speed.  So in
> practice, the fuel and spark events are equivalent to
> a 2 cylinder two-stroke engine (one spark and one fuel
> event per "crank" rotation).  To complicate matters a
> bit more, there is a set of trailing-edge spark plugs
> that fire substantially later.  They contribute very
> little to power or fuel economy, but clean up
> emissions a good bit by getting some of the unburned
> mixture at the trailing edge of the combustion
> chamber, which is a long, narrow rectangle that in
> profile looks not entirely unlike a set of cat-eye
> tail lights joined in the middle.  Many rotary owners
> will want to be able to drive these plugs as well. 
> Early Mazda rotaries used twin distributors (one for
> the leading and one for the trailing plugs); 1st gen.
> RX-7s used a single distributor with a complicated
> rotor to get the same effect (single coil and two
> plugs on each circuit).  2nd gen (and I believe the
> 3rd gen and RX-8) use 3 coils (one of each leading
> plug and one for both trailing plugs) triggered by
> ignitors, no distributor.  A common conversion for the
> 1st gen (and possibly earlier rotaries as well) is to
> use something like an MSD 6A on the leading plugs,
> using the two coils from a 2nd gen motor, and leaving
> the trailing plugs run off the distributor with their
> original coil.  We'll probably want to make several
> options available.
> 
> What's the status of closed-loop spark control?  Is
> this do-able under the current ion sensing setup?  I'd
> very much like that option; I believe at least one of
> the research papers I uploaded speaks to the practical
> application of ion sensing for that very purpose, and
> I believe it includes ion sensing traces for both
> over-advanced and over-retarded spark timing.  Of
> course there should be a regular open-loop map, both
> for a base for the ion sensing to work from and in
> case of ion sensing failure, as a backup.  The idea of
> having the ECU determine optimal spark timing on the
> fly, automagically compensating for engine and air
> temps, humidity, fuel mixture, etc. is something I
> find very desirable, not least of which is because it
> is very difficult for a typical DIY-er to be able to
> optimize a spark map without some high-dollar
> equipment most don't have ready access to.  A
> closed-loop setup would eliminate the need, as well as
> allowing compensation for things that cannot be
> adjusted for any other way (most notably humidity;
> this would even allow water injection on any engine
> without the need to figure out how much to adjust
> stock timing to make best use of it -- and I have data
> showing that it's quite possible for a typical
> gasoline-powered engine to make the same power with
> lower fuel consumption with a combination of water
> injection, spark advance over base, and a leaner
> mixture -- even under full throttle).
> 
> | Kawasaki Zephyr 615 (Daphne)       Kawasaki Zephyr 550 (Velma)|
> | "It was like an emergency ward after a great catastrophe; it  |
> |   didn't matter what race or class the victims belonged to.   |
> |  They were all given the same miracle drug, which was coffee. |
> |   The catastrophe in this case, of course, was that the sun   |
> |     had come up again."                    -Kurt Vonnegut     |
> | M/C Fuel Inj. Hndbk. @ Amazon.com -  http://tinyurl.com/6o3ze |
> 
> 
>  
> ____________________________________________________________________________________
> Have a burning question?  
> Go to www.Answers.yahoo.com and get answers from real people who know.
> _______________________________________________
> Diy_efi mailing list
> Diy_efi at diy-efi.org
> Subscribe: http://lists.diy-efi.org/mailman/listinfo/diy_efi
> Main WWW page:  http://www.diy-efi.org/diy_efi