[Diy_efi] RE: [offlist] Strain gauge on engine mounts

[Daniel R. Nicoson]

Marc,

I think the original thought of the toothed wheel with inductive sensors
will be the most durable and less hardware intensive than going optical.
Mounting the stationary sensors will be an issue regardless of optical or
inductive sensors.  Ideally if the sensors could be mounted on the bearing
housing then only the bearing tolerances would be an issue.

If you had a 2-channel O-scope hooked up to both sensors you would easily
see the wave forms shift apart as torque was applied.  I'm sure there are
circuits out there that can create a difference signal based on the phase
difference.  Then you just relate the difference signal to specific torque
values.

A quick Google for "torque sensor toothed wheel"

http://www.eetasia.com/ARTICLES/2002MAY/2002MAY08_AMD_MSD_DA_AN02.PDF

http://www.gmtcny.com/eps.htm

Google "phase difference error signal"

http://www.analog.com/library/analogDialogue/archives/35-05/AD8302/

I'd bet it is all out there.

Have fun,


Dan Nicoson


> -----Original Message-----
> From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org]On
> Behalf Of Marc Reviel
> Sent: Wednesday, April 20, 2005 5:32 PM
> To: diy_efi at diy-efi.org
> Subject: RE: [Diy_efi] RE: [offlist] Strain gauge on engine mounts
>
>
> At 5:02 PM -0400 4/20/05, Daniel R. Nicoson wrote:
> >I would stay away from optical on the driveshaft.  A very dirty
> environment.
> >Your original thoughts of sensing the gear teeth phase may be
> more accurate
> >than you think.  You just need to get the right person involved with the
> >right experience.
> >
> >Dan Nicoson
>
>
> I was really thinking it would be temporarily active.  Protect (or
> remove) when not needed.  But you're probably right.
>
> Beyond dealing with run-out and jitter issues regarding the shaft, I
> keep coming back to the challenge to RIGIDLY mounting the sensors
> relative to each other. Any vibration relative to each other in the
> measurement axis will compromise the accuracy big time.  The best way
> to solve that is going with that replacement 1" shaft with more
> 'twist,' increase the SNR.
>
> Still thinking about various optical ways that might eliminate some
> of these factors... need more thinking-fluid (Fat Tire Ale).
>
>
> --
> Marc Reviel
>
> PowerLogix
> http://www.powerlogix.com
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