Sensor Question

[Bernd Felsche]

Bruce tapped away at the keyboard with:

> From: "Bernd Felsche" <bernie at innovative.iinet.net.au>
> > There are 8 edges for timing in a 4-cylinder engine using a
> > hall-effect pickup in a distributor. They are accurately-machined.

> Might read some of the GM literature on that (hint, training
> literature on ignition systems).  It's copywritted so I can't
> mention it directly.

You just did mention it. Copyright prevents you from making copies
beyond fair use.

The GM literture would be similar to the lit. used by Volkswagen and
hence proprietary? In that case, it's restricted by much more than
Copyright - you'd have to physically sign an agreement not to
divulge details before being allowed to see the literature.

> > Flywheel teeth are not made very accurately.

> Have you read and compared (from various manufactureres) anything
> to support those statements, and would make them absolute truths?.

I'll rely on you as being the font of absolute truth as befits a
self-appointed deity.

Machinery design and engineering practice dictate the complexity and
hence the cost of machining gears. A low-duty, low-load gear
requires nowhere near the machining accuracy as those inside a
transmission; the duty cycle is so low, that the ring gear isn't
even lubricated.

If the machined and worn jitter of tooth signals is of the same
order as the crank speed variations, then an averaging filter to
eliminate jitter will also conceal initial crank speed variations.

On the practical side, Bosch abandoned the idea of using the
flywheel teeth in deference to a dedicated timing wheel, after
initial production and trials of Motronic.
----------------------------------------------------------------------------
To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org