PTO Dyno

[RonMar]

I don't see how or why you would attach the PTO pump to a lever arm and
how that gives you a torque measurement. If you want to use a lever arm
for torque measurement, then you are simply back to a driveshaft and brake,
with a lever to hold the brake.

Yes, use the pump like a hydraulic brake. Then as mentioned, you only need to measure the weight at the end of a known arm and RPM to calculate available HP. Any brake and lever arm method is going to turn that drag force applied into heat. Now, you can spray on water to cool the brake drum or rotor to deal with this(messy), or you could use a hydraulic cooler on the low pressure side of the restricted flow from the pump load system, back to the reservoir. Much cleaner in operation IMO...

With the variables involved with gathering these numbers from a restricted hydraulic flow, you would need to monitor, in addition to RPM, flow and pressure to make it as accurate as the braked lever arm already is.

Arthur Bell, when developing the first Bell helicopter returned test engines to vendors for failing to meet their claimed/contracted HP to Weight ratios. He determined this by measuring the torgue force applied to the helicopter tail boom at a given RPM, using a pull scale attached to a fixed object with a rope...

 

[dfkrug]

What you said in post #20 was right- calibration and some care is needed. The formula here is to calculate the hydraulic HP delivered by the pump. It does not tell you the amount of power it takes to drive the pump. It tells you the HP the pump is delivering to the point where the measurement is taken. Youd have to be careful in order to get good answers at different HPs. Pressure would have to be measured at the pump port for one thing, otherwise flow losses would cause an error from one flow setup to the next. Best measure torque and rpm on the input shaft.
larry

Yes, the formula gives the power delivered (dissipated) by the pump, as
I said. And it only indirectly gives the power needed to run the pump.
These hyd systems are generally regarded to be about 85% efficient, as
I also stated. So a .85 factor is used and callibrated with a known unmodified
tractor or 2.

But although I think a PTO pump and adjustable relief setup is an elegant
approach, it is certainly not cheap, as PTO pumps ARE expensive. JGENDR
correctly points that out. The drive shaft and brake has its advantages.

 

[jgendr]

Well I got in touch with the gentleman that built the pto Dyno today. He is sending me some more detailed pics and info on how he did it. Great guy to talk to!!!! He says he has like $25 in electronics and maybe $100 in the whole project. He says it good for up to 75 HP and over 1000lbft of torque!

NICE!!!!! When I get this thing together I'll be ready to test!!! And If all goes well, anybody interested can PM me and we'll see if we can put together a get together and do some dyno testing if your interested.


More to come soon!!

 

[dfkrug]

Well I got in touch with the gentleman that built the pto Dyno today. He is sending me some more detailed pics and info on how he did it. Great guy to talk to!!!! He says he has like $25 in electronics and maybe $100 in the whole project. He says it good for up to 75 HP and over 1000lbft of torque!

Sounds like a great project....and VERY reasonable costs, too. I look forward
to seeing pix of your dyno.

 

[California]

I am planning on useing a turbo from an Mercedes Benz 300TD

I wonder if a turbo off a Smart Car would be a better match. I'll guess those are 1500cc and turn 7,500 rpm.

Your Yanmar is what, 1,5000cc?? And it turns 2,500 rpm max.

A turbo off a car with 3x the airflow should be sufficient, I would think.

 

[SPYDERLK]

[[[Yes, the formula gives the power delivered (dissipated) by the pump, as
I said.]]] And it only indirectly gives the power needed to run the pump.
These hyd systems are generally regarded to be about 85% efficient, as
I also stated. So a .85 factor is used and callibrated with a known unmodified
tractor or 2.

But although I think a PTO pump and adjustable relief setup is an elegant
approach, it is certainly not cheap, as PTO pumps ARE expensive. JGENDR
correctly points that out. The drive shaft and brake has its advantages.

[[[No, including the energy of its output the pump dissipates the entire PTO HP, and you didnt say. The pump outputs/delivers approx 15% less than input, and the formula was used on output, without correction, to be the PTO HP.]]]

The fact that it was an indirect relationship was lost in #25, and should have been restated there and in every case where special measures are needed on a case by case basis to produce accurate results.

Hydraulics is a good approach. As you say, if the hardware is not on the shelf idle youre going to spend some $ setting it up.
larry

 

[jgendr]

To All Interested,

I contacted the gentleman on his dyno that he built, He updated his website with more detaild pictures and info on building it.

Great Guy and great job!!!!

If you are interested in this project check out his updates:

Tractor Dynomometer

It's time to play Folks !!!!! LOL


California:

Most of those turbos that you are refering to are t3 t4 type turbos and a gas turbo will not spool as fast as we want. You are correct there, however the mercedes Benz 300 SD is a diesel, and has the smaller exhaust turbine which will make it spool quickly for my application. Yes It will make more boost than I actually need, but the other nice feature it has is an adjustable waste gate where you can set the boost that you want! Something most of the Gassers cant do unless you use an external waste gate which addes $$$$ to the project.

This is gonna be fun!!!!

 

[dieselgeek]

California:

Most of those turbos that you are refering to are t3 t4 type turbos and a gas turbo will not spool as fast as we want. You are correct there, however the mercedes Benz 300 SD is a diesel, and has the smaller exhaust turbine which will make it spool quickly for my application. Yes It will make more boost than I actually need, but the other nice feature it has is an adjustable waste gate where you can set the boost that you want! Something most of the Gassers cant do unless you use an external waste gate which addes $$$$ to the project.

This is gonna be fun!!!!

There is no designation by turbo manufacturers as "gas type" or "diesel type" - also, most OEm turbos include a wastegate but not necessarily all are adjustable to the range you're looking at.

What's the displacement on your tractor engine? I have a feeling the 300D-T turbo off the inline 5 mercedes, which displaces 3.x liters, is going to be way too big to provide the low boost you're looking for. The best way to find the right junkyard turbo is to calculate your engine's airflow in CFM, then lay that over a compressor map which is available for nearly every OEM turbo out there. Not2Fast: Where Science Hits The Road is run by a friend of mine, he's got maps and a program that lets you key in your engine specs - it might work for this application. If confusing, let me know and I'll try to help you find out exactly what turbo would fit your needs. My gut says something off a 2 liter (or smaller) turbodiesel, like a VNT turbo off a wVW TDI engine, or possibly a 14B turbo of a 2 liter Mitsubishi gas engine, is going to be more appropriate.

-scott

 

[Treemonkey1000]

To All Interested,

I contacted the gentleman on his dyno that he built, He updated his website with more detaild pictures and info on building it.

Great Guy and great job!!!!

If you are interested in this project check out his updates:

Tractor Dynomometer

It's time to play Folks !!!!! LOL

This is gonna be fun!!!!

So Jgendr how is the dyno project going?

 

[jgendr]

Gettin Parts and doing auto cad drawings now!!!


Ive got the schematics from the gentalman that designed it, and working on getting the electronics or researching data loggers now