Thermal Sensor and Load Sensor

[Andrew W. Macfadyen]

I heard of radio telemetry being used for this type of application, but it
wouldn't be viable as a long-term solution.

Andrew Ghali wrote:

> >There is a rotary load sensor on the market.  The company is called 'Land And
> >Sea" , they make dyno stands and a real time on car dyno.
> >
> >The real time on car dyno uses a rotary strain guage that replaces the drive
> >shaft yoke.  From what I remember of their info sheet, there is also a front
> >wheel drive system avalible.
>
> The problem with strain gauges is that you'll need a) some sort of slip ring
> contacts for the rotating part or b) magnetic power and signal coupling to
> transfer as a variable frequency, right?  The problems with (a) are obvious;
> (b) is a bit complex and probably fairly expensive, and subject to calibration
> problems.  The concept of a phase-based sensor is old, and can utilize the
> same technology used in synchro/resolver equipment.  Yes, filtering would be
> required on any method - your data will be delayed a few turns of the shaft -
> not too bad?  The one problem that none of these methods addresses came up
> in a discussion with a Motorola automotive-group field application engineer:
> work hardening of the shaft.  You are depending on a known modulus of the
> shaft in order to determine the torque from its deflection.  That's what the
> Moto guy told me was the reason the method was not used in passenger cars.
> I suppose race cars with new shafts every race would have no problem, but in
> the long haul...
>
> As an aside; somebody mentioned MAP, RPM, & a cal table instead.  I'm no
> expert here but this seems pretty rough to me.  You'd have to add about a
> dozen other values in before you could get close - like advance/retard,
> AFR, engine temp, air temp, etc. then add in other constants like engine
> friction, efficiency, etc.  Once you had all that cal'ed from a series of
> dyno runs, the next time you changed your air filter, or over time as your
> rings and valve seats wear...
>
> I hope I haven't muddied this up too much.  I am intrigued about the
> commercial systems though.  I'd like to know how they've solve some of
> these problems and what approaches they used.  It's the engineer in me.
>
> Andrew