Current/New ION information

[Peter Gargano]

I just found this article by Ph.D. student Lars Eriksson from  Link=F6pin=
g
University, Sweden. The work was done in collaboration with Mecel AB and=20
SAAB Automobile AB. It's dated 25 November 1998.

Here is the summary:

   http://www.fs.isy.liu.se/~larer/Projects/ionint.html

And here is the actual article:

   http://www.fs.isy.liu.se/~larer/Projects/main.html

Put simply, this article cites research that says maintaining the peak=20
cylinder pressure at a particular number of degrees (after TDC) will
maximise engine efficiency and smoothness. This point is called the peak
pressure position (or PPP). The PPP varies with many environmental condit=
ions
such as inlet air temperature, humidity, etc. PPP can be estimated by mea=
suring
the ION current, and in particular the "shape" of the ION current. Knowin=
g=20
the current PPP value, the ignition timing can be varied to position the =
peak=20
pressure at the optimal point.=20

Perhaps a paragraph from the summary better describes the article...

>  We are studying a method for controlling the spark advance that is bas=
ed
>  on pattern recognition on the ionization current, in a fast inner loop=
.=20
>  An idealized model of the ionization current, with six parameters, is =
fitted
>  to the measured ionization current. Information extracted from the fit=
ted
>  model is then used to control the spark advance.=20

I'd recommend all interested ION project people look at this article as i=
t
also summarises much of the research that has been carried out to date. I=
t
also provides a common information database from which we can all work fr=
om.

So, we're talking about engine optimisation, not just knock/pre-ignition
detection!

regards,
--=20
Peter Gargano     mailto:peter at mail.techedge.com.au
Ph: +61 2 6251 5519            Fax: +61 2 6251 6646