Current/New ION information - (resent)

[Peter Gargano]

||  Sorry about the mangled text (I cut and pasted an 8 bit character
||  and it stuffed up the rest of the text...). Here it is again...

I just found this article by Ph.D. student Lars Eriksson from Linkoping
University, Sweden. The work was done in collaboration with Mecel AB 
and 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
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 conditions such as inlet air temperature, humidity, etc.
PPP can be estimated by measuring the ION current, and in particular 
the "shape" of the ION current. Knowing the current PPP value, the 
ignition timing can be varied to position the peak pressure at the
optimal point.

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

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

I'd recommend all interested ION project people look at this article 
as it also summarises much of the research that has been carried out 
to date. It also provides a common information database from which we
can all work from.

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

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