Digijet - Digifant

[Bernd Felsche]

Peter Gargano tapped away at the keyboard with:

> Bernd Felsche wrote:
> > Cylinder-selective knock control is available on all Digifants, not
> > just the supercharged ones.  This is documented in several SAE
> > papers presented by Volkswagen staff in the late 1980's. The
> > supercharged ones had boost control under persistent knock.
> 
> I take it that selective knock was handled by timing alone,
> or did it include mixture too? Was this in hardware, or
> just software (GM do timing in hardware)? Do you have an SAE
> reference, or a URL?

It's timing-only.  There's a bandpass filter (shown as an amplifier)
and integration hardware that's then fed into the microprocessor;
according to SAE 890388.

Jens provided me with details of SAE papers and some German-language
references that are pretty hard to obtain in Oz.

        SAE Paper #861586
        European and US Engine Design Concepts After Introduction
        of Unleaded Fuel in Europe
and
        SAE Paper #890388
        The Electronic Motor Management System DIGIFANT

You'll have to slow-order them from the SAE (http://www.sae.org) if
you want a copy; or maybe a library can find them - prehaps in a
proceedings volume. SAE's online catalogue only goes back to about
1990.

The papers aren't especially enlightening anyway; they outline some
algorithms, architecture and some design choices. I can only locate
the latter on my shelves; the former was more detailed, providing
timing information, etc. The latter is useful in that it illustrates
the incarnation for supercharged engines.

-- 
Bernd Felsche - Innovative Reckoning, Perth, Western Australia
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