[Diy_efi] measurement of tailshaft Twist

[mark krawczuk]

hi, how about  scribe/draw some  dead straight lines  along the length of the tail shaft, then u`ll see if  the shaft twists
mark 
t


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  ----- Original Message ----- 
  From: Bill Washington 
  To: diy_efi at diy-efi.org 
  Sent: Thursday, April 21, 2005 11:41 AM
  Subject: [Diy_efi] measurement of tailshaft Twist 


  Gents,
      A couple of questions:
      1. How would you compensate for vertical and horizontal movement of the tailshaft (due to engine movement) relative to the sensors? While it may be small I believe it could generate much larger phase errors than the signal that you are trying to measure.
      2. This method is only (possibly) suitable for rear wheel drive vehicles with an exposed tailshaft - I do not see how it could be implemented of front wheel drives (and even 4WDs where the torque is split between two - front and rear -  driveshafts) or vehicles with enclosed tailshafts (torque tubes).

      Thoughts???

  Regards
  Bill




-----Original Message-----
From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org]On
Behalf Of niche at iinet.net.au
Sent: Wednesday, April 20, 2005 8:03 AM
To: diy_efi at diy-efi.org
Subject: [Diy_efi] RE: [offlist] Strain gauge on engine mounts


At 07:51 AM 20/04/05, you wrote:
  
Not sure that is such a good idea Mike ... the rubber is non
linear ... just like the mounts would be, and resolving the
edges requires some very fast counters at high speed and
quite big counters at low speed ... plus who wants that much
slop in the drivetrain ... it's not like you can swap this
thing in and out all that easily is it?
    

Interesting point, think I misread this initially too, way too
many mailboxes here...

I think it should be possible to do this without any rubber,
and avoid any drivetrain slop and be fully differential
in respect of drivetrain lateral or even axial motion... !

I mean, consider this:-

a.   Toothed ring gear (pitch to be determined) on tail shaft
      close as possible to universal joint, firmly attached

b.   Second toothed ring gear as above but at furthest other
     end so max length of tailshaft between gears

c.   Tailshaft balanced appropriately

Question arises, would there be enough twist of the tailshaft
over the most appropriate length for the dynamic range of
torque measurement needed ?

ie. At lowest extreme the tailshaft twist may be so low that
there wont be much discernible phase shift for a coarse
pitch ring gear.
At highest extreme it may well skip a cycle if too fine pitch,
so a sync method would be needed if one is interested in
wide dynamic range - which obviously is fairly easy to implement...

Any mech structural engineers here care to estimate degrees
of twist for say 100 newton metres of torque over length of say
650mm and 80mm dia... ?


  
Regards from


Mike Massen
Perth, Western Australia
VL Commodore Fuse Rail that wont warp or melt !
http://niche.iinet.net.au
    

  


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