Ignition timing in conjunction with

Woodd, Michael wooddm at akcity.govt.nz
Thu Sep 19 22:39:56 GMT 1996


>There appears to exist a number of sensors to build
>an excellent self tuning EFI, yet the only sensor that
>anyone talks about for ignition timing is a knock
>sensor that just tells me - oops too much -
>self destruct sequence initiated.

I posted similar musings to an unreceptive audience
in efi332 a while back, could have been the house was
empty, but here I go again....

I have thought about this an awful lot, and plan to put
some of my ideas into practice, once I figure out how
to actually build the thing...

The only thing stopping you having a computer tweak the
engine parameters for you is that you have to have
*accurate* *results* from your measuring system.
It seems to me with an accurate performance measure-
ment system, anything is possible, but building an
*accurate* system is a bit of an ask.

Consider a car on an absolutely perfectly flat piece
of concrete, on an absolutely still day, with an
absolutely even ambient air temperature/pressure.  Now
theoretically, you can measure your acceleration and
speed down to a t, factor in total car weight (however you're
going to measure that...), drag coefficient if you like, RPMs...
whatever else you need to get torque and real horsepower.
I dont even know the physics well, but I figure it can be done.
Use some fuzzy logic to try to improve things over
multiple acceleration runs, hey presto, self tuning car.

But of course we all know that the original premise is
absolute B.S., even an aircraft runway would have trouble
delivering.  Bumps on the road will produce lumps in
the acceleration curve if you're measuring wheel speed,
how ill it know when we are climbing slight rises,
how will it know when we are cornering,
how will it account for headwinds...
What about putting this on my bike??!!

Of course there are sensors that could capture information
that could largely negate all of these, and I am keen to
try and implement most of them.  Put in a knock sensor,
and try to use EGO as much as possible, including in
non-steady-state situations, to make sure we are heading
in the right direction, *heaps* of memory to record
multiple instances of the same speed/RPM/TPS for
different spark/fuel parameters, historical EGO info...

My idea is to have this running for a race track environment,
where the car is doing multiple acceleration and speed runs,
repetitively, and I think given a baseline spark/fuel curve, it
could quite quickly approach the perfection asymptote...

I have no idea how complex the software will be to get there,
or what kind of processing grunt will be required.  I am
going to start with a '552!!!  What it is capable of I don't know,
but being of an empirical nature, I hope to find out.

>I truly hope that there are some good ideas out there.
>
 Where yours????? ;-)

Mike Woodd
(wooddm at akcity.govt.nz)
Anybody need a race car driver?  No, really, I'm quite good....



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