PTO Dyno

[jimgerken]

If I read carefully enough, no body suggested an inertial dyno. Is that type out of the question due to the higher HP numbers you wish to measure?

 

[RobJ]

Personally, I'd fear tearing up a drive line hooking a dyno to my PTO with a hopped up engine. Wheel slipping is one thing,but how would you calculate a safe slip on a PTO?

I agree but it should be able to handle it. Basically to find out the max hp and torque curve, you load down the engine until it falls on it's face.

 

[RobJ]

So theoretically adding a turbo at 5 - 7 lbs of boost, a litte more fuel, and a little more timing will give you aproximatlly 10 - 12 hp.

Adding 7 - 10 lbs of boost will = 15 - 20 hp, 10 - 15 lbs of boost and an intercooler could get you upwords of 30 + hp.

hehe, all your math looks good until I got here. now you are guessing. Double the hp and isn't going to last long...the tractor internals either.

When I tested the diesels I rebuilt we had a water brake system. It had it's on tank under it. I think there were only 2 sensors, rpm and the torque pressure. Only 3 digital readouts, rpm, hp, torque. This was about 1980.

Sounds like a cool project but I still don't see the reason on turboing a 20hp diesel. But keep the info and pics comming!

 

[jgendr]

If I read carefully enough, no body suggested an inertial dyno. Is that type out of the question due to the higher HP numbers you wish to measure?

You have any links on the subject? I'm open to all possibilities and solusions.

You got to remember the the hp rating are anywhere from 10 - 100 hp and torques in the range of 100 - 2000 ftlbs. Inertial dynos work great for measuring hp and tq for trucks, cars and such but not very useful on this application. the threory it. put the pto in gear, put the tractor on WOT ( Wide open throttle ) and load it down to see Brake horsepower at the pto. This is easily used to calculate actual enging hp.

In the inertial application you start at a given rpm and measure the force when you hammer down. That's a great way for measureing your giddy up and go on a truck but the tractor runns too slow and geared for grunt.

I suppose you could use the same pricipal on the pto say from idle to WOT but you would need a heavy flywheel to measure the torque curve. Not out of the question though


Nice input keep it coming

 

[neucam]

I'm proud to say that my 01 dodge lay's down and impressive 535hp and 1132lbf of torque where the rubber meets the road and I get an impressive 23 mph on the highway. We certify these numbers on a big dyno machines at our events.

I do not understand, dyno figures told you you were getting 23mpg. In real life a dodge diesel PU stock or modified only gets that figure at 55mph light throttle no load. In real life it barely gets 18.

 

[jimgerken]

Inertial dynos do not measure force. The data collected is simply rpm and time to accelerate a known mass. If you think about it, that's all you need to calculate torque (and hp). google "TDK inertia dyno". this explains it very well, but keep in mind what they are describing is for gocart engines. Its your job to size it for your application. Just a suggestion.
For small tractor use, I would think it would be an afternoon's job to take a 540 rpm hay baler impliment, add a once-per-rev counter (optical), and a pc to count and convert to rpm, graphing results. The baler is made for 50 HP or more, so any engine smaller will spin up the flywheel with measureable time lag. Calculate the mass of the flywheel, and you have everything you need.

 

[SPYDERLK]

Inertial dynos do not measure force. The data collected is simply rpm and time to accelerate a known mass. If you think about it, that's all you need to calculate torque (and hp). google "TDK inertia dyno". this explains it very well, but keep in mind what they are describing is for gocart engines. Its your job to size it for your application. Just a suggestion.
For small tractor use, I would think it would be an afternoon's job to take a 540 rpm hay baler impliment, add a once-per-rev counter (optical), and a pc to count and convert to rpm, graphing results. The baler is made for 50 HP or more, so any engine smaller will spin up the flywheel with measureable time lag. Calculate the mass of the flywheel, and you have everything you need.

Yould have to know the mass and inertial moment of all spinning[rotationaly accelerating] parts of the driveline. Tractor engines, flywheels, transmission, etc, are heavy for their HP compared to a kart settup. When being accelerated at higher and higher rates as you "hop up", those parts become increasingly parasitic to the measurement and must be factored in.
larry