Q&A Forum
I have seen several on this forum building hydraulic pump style dynos.
Several have attempted to use a stepper motor on the flow control valve.
They seemed to struggle with their design and asked questions, but I have not seen a working version posted.
Here is what I have put together for kart engines. (mainly 15-30 hp)
34cc pump @ 3000 rpm
1" input line
3/4" output line
I initially purchased a 3/4" flow control valve, but I also now have a 1" valve. Some say the smaller valve is harder to turn and I can use the larger valve if it helps.
My question is what size stepper motor have people successfully used in a similar application?
Jeff
Thankyou very much!!!
Thank you for sharing those.....great information !!
Jeff
2nd file , seems the first one worked. Bare in mind there maybe different approach now that we are in 2020.
Hi, if you will find the pdf post here, it is usefull. Yoday I added the 2nd fan to drive out air from dyno cell, now the 2 fan drives out air at 3700m3/h, so the air in the dyno room changes 5 time for minute.
Sorry for the long delay had to search back all the way to the year 2009, I just hope the files ain't to large. Here it goes and if it fails I will email the files to Jostein and he can post them. Fingers crossed and it works now! I have two files to post happy reading.
Hi, if you will find the pdf post here, it is usefull. Yoday I added the 2nd fan to drive out air from dyno cell, now the 2 fan drives out air at 3700m3/h, so the air in the dyno room changes 5 time for minute.
Hi captndiet how is your build coming along ?
"DYNO ROOM CFM DEMANDS" fresh air supply to a enclosed dyno_room is very tricky.
Nothing beats a direct ducting air system to outside atmospheric air pressure source hanging over the test engine intake . But you might drive your neighborhood crazy.
Like Eric mention home dyno rooms are limited with house hold power supplies avaliable to tester.
From memory I think Eric was developing his 125cc gokart racing engines. Which a 125cc engine compared to a 500cuin prostock engine will have totally different demands for dyno_cell build.
I have a PDF file somewhere that superflow have well documented the process of setup a dyno_cell just have to located it and post it up here on the forum_board.
Have a look at this nice setup
http://www.theoldone.com/articles/Dyno_Room/building_a_dyno_roomfinal.htm
MERRY CHRISTMAS EVERYONE!
The fan that drive out exhaust gasses is about 2000 m3/h. The fan that drive out air in my dyno cell is about 1800m3/h 220v. I think it is difficult to have 10 times bigger fan with home electric system.
I work out of the dyno cell. Today I sealed the cell and I have done some test. In garage no smoke and little smell inside dyno cell.
Eric
The amount of airflow the manufacturers recommend is much higher than your or I would imagine.
“With a dynamometer test cell, we want the air to change eight to ten times a minute, and it needs to go across the engine. I’ve been in test cells before where I walk around and the air comes out of the ceiling, goes straight across the floor, and out the back – the engine never sees it. You need to figure out the cubic feet of the room and multiply it by ten to determine the volume of air you need to properly feed the engine,” (Bret Williamson @ SuperFlow Dynos)
https://www.enginelabs.com/news/aetc-2013-superflow-discusses-dyno-layout-design-achieving-results/
Small Engine Cell = 8' wide x 8' deep x 8' high, CFM calculations work out to a minimum of 5,000 for a small engine cell. (Land & Sea Dynos)
https://www.dynomitedynamometer.com/dyno-tech-talk/dynamometer_test_cell_consruction.htm
Hitting these flow numbers would not be hard for me, but keeping the incoming air temperature stable would be.
Jeff
I use 2 fan, one in the exhaust silencer and one at the top of the room to drive out any other exhaust smoke. But in not completely satisfacted, there is a lot of smoke aniway.
What you'd want for this kind of aplication is a pilot operated proportional pressure relief valve....
once you start thinking that way it makes a lot of sense....
Nice !!!!
How are you handling the air in / air out?
Do you use a fan on the exhaust tube ?
Jeff