real-time engine torque measurement
real-time engine torque measurement
(OP)
anyone have a slick method for measuring real-time engine output torque in a running/installed engine? In my case, the engine and driven equipment each have multiple mounting locations, and the engine block is "rigidly" connected to the driven equipment. Could conceivably do strain gages on the crankshaft tail with a slip ring, but I was hoping for something a bit more robust (want 30k hours life).





RE: real-time engine torque measurement
RE: real-time engine torque measurement
Bring your wallet.
Mike Halloran
Pembroke Pines, FL, USA
RE: real-time engine torque measurement
Mike, yes, it looks like they've got what I'm after (especially the red disc one). I can see just from looking what you mean about the wallet.
RE: real-time engine torque measurement
Not sure if this can be adapted to your particular application, but if you have a single output shaft transmitting the torque, it may be suitable. (And parts are readliy available, cheap.) We've used this system with optical pickups as well to measure the phase shift, which promised to be simpler, however any dirt or oil covering the optical strips caused grief.
Robin Sipe.
RE: real-time engine torque measurement
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: real-time engine torque measurement
- Steve
RE: real-time engine torque measurement
Measuring at the mounts sounds like a good idea (one of the first I considered), but many such engines are packaged by third parties with unknown (to me) driven equipment, which might impact the results.
the concentric shafts idea sounds interesting. I'd been thinking about a 2-piece flyswheel for a similar setup. I wonder whether the system could be made robust enough for production use in an industrial piston engine application (~40L-70L total displacement). That's the end game, and might change the feasibility of some ideas.
RE: real-time engine torque measurement
I have checked the torque calibration on certain turboprop engines with a test instrument called a "Lebow", that mounts bettween the propeller and engine drive flange. It contains strain gages ( as mentioned ) and a slip ring affair for the telementry.
RE: real-time engine torque measurement
some tractors I have worked on with hydrolic gearbox have in place of a clutch a twopiece flywheel . the first half ridgidly connected to the engine the other half spring loaded to the first half and connected to the hydrolic pump . It has a magnet stuck on it with a pickup to read it position relative to the first half input, thus a torque value.
RE: real-time engine torque measurement
There are lots of ways to measure real time torque in a running engine. The easiest would seem to be using load cells at each engine mounting point. That is where the engine torque moment is ultimately reacted.
Turboshaft engines use a concentric drive and reference shaft arrangement, with hall effect sensors on each, for measuring torque. This shaft device is called a "torquemeter". But this would require you to engineer and build a fairly expensive piece of hardware.
The radial aircraft piston engines of the 40's and 50's used a floating ring gear in the reduction gearbox that had a helical spline on its OD. The thrust reaction forced the ring gear against a set of hydraulic pistons that pressurized a hydrostatic fluid circuit. The resulting circuit pressure was converted to a BMEP rate by a dial gage. This method would only be practical if you were designing and building your own gearbox.
If you want to do something super-high-tech (but expensive), check out this "magnetomechanical" gizmatron:
http://www.magcanica.com/products.html
Regards,
Terry
RE: real-time engine torque measurement
RE: real-time engine torque measurement
PB-II shown here http://www.magcanica.com/torque.html sounds very interesting - I wonder how long the magnetization lasts?
hemi - you'd have to assume that combustion is happening properly, which is one of the things I need to verify w/ the measurement.
RE: real-time engine torque measurement
Put a tubular spacer between the bellhousing flange and the load's flange. Put strain gages on that to measure the reaction torque.
Mike Halloran
Pembroke Pines, FL, USA
RE: real-time engine torque measurement
If you can access the flywheel or flexplate OD, a Hall effect sensor with a high sample rate should be able to measure the variations in angular velocities (at, say, the starter ring gear teeth) produced during any given crank rotation. The starter ring gear is a large diameter with lots of teeth, so it should give fairly good resolution.
Of course, you would need to do some mapping of the engine torsional characteristics beforehand, in order to make sense of the results you will get in operation.
Good luck.
Terry
RE: real-time engine torque measurement
RE: real-time engine torque measurement
If anyone is interested in this and please no tire kickers as he does not have the time for that, please respond to this thread and I will find his email address and post it. First though, I want to get his permission to do so.
Larry