Sensor Question

[Bernd Felsche]

Bruce tapped away at the keyboard with:
> From: "Bernd Felsche" <bernie at innovative.iinet.net.au>
> Subject: Re: Sensor Question
> > 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.

> So now you are advocating disclosing copywritten material yet when you
> mention email, it's a different matter.

The concept of Copyright has been explained before.

Email communications to an individual _also_ carries a reasonable
expectation of privacy. If it's not published, no Copyright exists.
For any correspondence to be published, it is the publisher's
responsibility to ensure that the correspondent approves of
publication.

> Rather then confuse the issue because of your statments, I'll just
> let things stand as I first stated them.

> > 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 you had the above referenced materials, you'd see what errors
> there are in your assumptions.

Try Morrison & Crossland's text on machinery, machinery handbooks,
Bosch Automotive Handbook, ...

> > 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.

> So from Bosch's experience you make a generate statement for all
> manufacurers, OK, fine.

Not all; just the ones willing to learn from somebody else's
mistakes. Bosch ie OEM to the majority of European manufacturers,
licences technology to North America and Japan.

If the cost accountants tell the Engineers that they can't afford to
put a separate timing wheel on a dispose-mobile, then the Engineers
have to make do as best they can. Should the TPU of the available
ECU require crank timing signals like that of a multi-tooth crank
timing wheel, then the flywheel is the lowest-cost solution for
manufacture as no ECU re-engineering is required.

If the manufacturer values quality and performance, then a separate
timing resolver is incorporated. Hence BMW, Volvo, Mercedes, Audi,
etc., use of a separate device; because it performs better and is
more reliable.
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