[Diy_efi] Strain gauge on engine mounts

Milosz Kardasinski miloszk
Wed Apr 20 01:55:00 UTC 2005


It's a good idea, however, it's really application specific. My motor mounts
are
very stiff; on top of that they have positive stops integrated into them
that prevent
the urethane from being over stressed. With my foot to the floor I hit the
stops
on a regular basis which could be a problem with this method.

What one could do is to make a simple brace that can easily be attached to
an
engine. Make the brace pivot on both ends so that the load is mostly axial.
Attach
the strain gauge to the brace and use the strain to compute torque.

The brace can be removed when not needed and is simple to service if the
strain
gauge should fail. Granted a dyno is the best method to measure torque or
even
one of those driveshaft meter things. However, we are thinking outside the
box
on this one...

Cheers,
M.


----- Original Message -----
> Gents,
>     Here is a relatively low tech thought for measuring engine torque.
>
>     We know that the engine rotates against the mounts with torque,
> therefore there should be a relationship between rotational movement of
> the block and torque - yes, nonlinear and different for each vehicle and
> will also vary with aging of the mounts and changing mounts  - would
> therefore require a calibration method - however if we measured the
> angular movement (could be done with optical or a variety of other
> sensor types ) then manually rotated the engine against the mounts
> (engine stopped, out of gear) while measuring the applied force by
> distance (torque) and logging the related sensor reading that should
> provide a reasonably close calibration - probably as close as any of the
> other methods mentioned.
>
>     A similar method could be used for measuring the torque at the
> wheels - linear displacement of the wheels relative to the body will be
> related to force (to the road) by distance (rolling radius of the wheels).
>
>     What think you? Flame away!
>
> Bill





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