Dyno Installation

[NewfieEng]

I have been assigned the task of installing a Dynamometer for my company’s engine shop. I have had some experience with Dynos, but not much. The Dyno is already purchased all I have to do is install it and get the computer up and running for it. This seems like a bit of a daunting task but I love a good challenge so I am giving it a try.

Before I even start trying to do what is asked of me, I want to familiarize myself with Dynamometers and different types of software that are used.

Does anyone out there know of some useful websites or articles on the basics of Dynos?

I know what they do and the theory on how they work, what I need to learn more about it the actual parts of a dyno and the electrical/mechanical requirements for installation. I know this depends a lot of the type of dyno (water brake or other types), but general information on all type of dynos is what I am in search of.

Any help would be appreciated

 

[dgallup]

Well, you really need to let us know if it is an adsorbtion or an inertia dyno because they work in fundamentally different ways. Adsorbtion dynos typically run at constant speed and have to dissapate all the power the engine is producing. There are many ways to do this. Inertia dynos, like the speed shops use, do not dissapate any power and can not opperate at constant speed, they are purely transient beasts. All the engine power is converted to kinetic energy by spinning the dyno inertia up to speed. Then you have the emmissions dynos that are a combination of the two. The control software is totally different.

 

[CNGBrick]

A good read is "Engine Testing Theory and Practice" by Michael Plint and Anthony Martyr, ISBN 0-7680-0314-8, available through SAE. I recommend reading it before you start your installation.

Richard Thomas

 

[NewfieEng]

I am pretty sure it is an inertia dyno that uses water to disipate power.

 

[Warpspeed]

There are three distinctly separate aspects to this.

First there is the control of the actual dyno itself. That will obviously depend on the method of power absorption used, but basically it should control water flow, or the dc drive current in the coils of an eddy current machine. It will need to control engine Rpm in some way, by measuring Rpm and using that to control the load. You may require constant Rpm to be held, or need some sort of ramping of Rpm, depending on how you wish to test. With an inertia dyno, a fairly simple control system will be needed, but it will still require some sort of control system for safety reasons, and braking, if for no other.

It may be very difficult or impossible to find off the shelf software to do exactly what you want. Mainly because of the different types of dyno and different applications and interfacing requirements. A dyno guru may be needed to build something and write some software.

The second requirement is a lot easier. Something is required to read the power produced by measuring Rpm, torque, or perhaps time with an inertia dyno. Commercial software is fairly readily available that will read and plot the output from a dyno, display figures, and record results. These software packages look good, but remember they will not usually CONTROL the dyno, only read the output.


The third requirement is all the other instrumentation to go with the basic dyno. Temperatures, pressures, flows, and so on. Some sort of data acquisition and logging will definitely be needed, and that too should be fairly easy to purchase commercially.

I guess it all comes down to how deep your pockets are.

 

[mburgess]

This is a little off the topic but one thing that is often overlooked with dyno installations is the ventillation setup of the dyno room. If this is not done adequately there is the obvious health risk of build up in exhaust fumes.Also alot of heat is generated, this in itself can often distort your results.
Regards,
MB

 

[Warpspeed]

Yes, heat, fumes and noise are always big problems to overcome.

But also think of safety. Some sort of sudden structural failure can be very dangerous. So orientate the dyno so any flying parts will hopefully be in a relatively safe direction.

Sudden flash fires on dynos are far from unknown too, so be prepared.

 

[BobM3]

If you can't find off-the-shelf software for control and readout, you might want to look at National Instruments Labview Software (

http://www.ni.com).

It's customizable and they offer conditioning for readouts and current and voltage outputs to drive the loading mechanisms.

 

[GregLocock]

Make sure you are well set up to handle oil fires. I think in 3 years I saw 4 serious oil fires on our dyno (for good reasons).

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[WilliamH]

NewfieEng,

"Does anyone out there know of some useful websites or articles on the basics of Dynos?"

Go to Superflow.com. There is a tremendous amount of information regarding dynamometers and test cell construction there.

In over thirty years of operating engine dynos, the most overlooked aspect of cell design is adequate air replacement. We operate more than one engine dyno cell here and pay utmost attention to ALL fluids (temps, etc) including air.

If repeatability is to be within reasonable variance, cell air must be FRESH OUTSIDE AIR at all times during the pulls. That means NO vapors of any kind from the engine or cooling system lingering in the cell.

We also calibrate our dynos daily and log this information as part of our quality program.

 

[Craighell]

If your dyno is an inertia dyno, it won't use water. It could be an inertia dyno with a water brake attached for steady state/ step and hold testing.

I agree that air flow through the room is of utmost importance. Plan on feeding 150 cfm of fresh air for every 100 hp. Then add to that 900 cfm to cover exhaust contamination for evry 100 hp. That said 500 hp testing will require 5250 cfm of air in and out of the room (at a minimum!). I try to double that vaue, my self.

Good luck with your project.

 

[mburgess]

Don't just look at airflow for required HP, also look at the volume of room & the number of airchanges per/min. Think if you had an engine blow & an oil fire you could have a large build up of gases. As WilliamH state you need fresh outside air, introduce it at a low level into the room & exhaust at high & low level with a flexible duct & shroud for the exhaust pipe. You would want at a minium two complete airchanges per/min. For the exhaust pipe normal a/c flex will melt or blow out from the engine pulses. There is a bendible aluminium flex (known as "sidewinder" here in Aus) availible that can be used for the 1st meter then a heavy duty industrial flex can connect it to your exhayst ductwork.
Regards,
MB

 

[schmidtj86]

"Engine Testing Theory and Practice" second edition is a great SAE book by Michael Plint and Anthony Martyr.

Covers almost all aspects of equipment choices and designs, building dyno cells, and engine testing. I highly recommend it.

 

[gmh265]

I found this writeup just after we installed our second dyno test cell and found it interesting and partly informative.

http://www.theoldone.com/articles/Dyno_Room/building_a_dyno_roomfinal.htm

 

[kenre]

i have used dyno datalogging and software from

http://www.performancetrends.com

may not be what your looking for buts its another option.

Ken

 

[Craighell]

Also check out this page:

http://www.stahlheaders.com/Lit_measurement_1.htm