[Diy_efi] RE More ECU progress

[Mike Yates]

woo...hoo.... that means I could potentially use your ecu for the
"stroked" rotary im designing.

Mike


On Wed, 28 Feb 2007 12:32:38 +0000, you wrote:

>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).
>
>My design can handle this as one of the chip registers is a cycle angle 
>register. This sets the maximum that the crank angle value can become 
>before it is reset to zero.
>
>obvious values are 720 for a four stroke and 360 for a 2 stroke :)
>
> > To complicate matters a
>> bit more, there is a set of trailing-edge spark plugs
>> that fire substantially later.
>
>Not a problem. simply hook up three more of the chips outputs to spark 
>driver MOSFETs and tell the CPU to add three more spark events to the 
>event table at the deisred advance.
>
>> What's the status of closed-loop spark control?  Is
>> this do-able under the current ion sensing setup?
>
>Well, the timing controller can certainly handle the programming of any 
>timing for spark.
>
>the practical implementation where the CPU reads the ion data and 
>processes it in order to recalculate the timings it programs into the 
>timing controller will have to wait until the system is on a runnable 
>engine.
>
>The point is - the hardware design _can_ do this already.
>
> > 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).
>
>Nice :-)
>
>the timing controller also would allow one to hook up injectors for gas 
>/ nos / water / anything else without any trouble at all. the controller 
>doesnt care what the event is for, it just triggers it.
>
>Hm, actually, Im going to increase the size of the fuelling table to 
>allow  other types of injector to be PWM'd too. Thanks for getting me 
>thinking on that one. I think 256 entries should be ample...
>
>(sheesh, here was me thinking 32 independant PWM'd outputs would be 
>enough... I think I'm going to have to use staggered timing on the PWM 
>clock to prevent silly loads being applied to the power source at high 
>frequencies...)
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