Gallery, Projects and General > How do I??

Dynamometer - a friend questioned and i have no idea.

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NeoTech:
Dynamometers is a interesting subject.. So i started to pondering this a couple of days ago. And i could not wrap my head around it really..

But here is my theory anyway.. And this is for a inertia brake simulator type dynamometer.

Let us say we a have a high volume high rpm gear pump connected to the output shaft of an engine/transmission. It would be free to rotate with the motor so a 1m torque arm would be attached to the pump, that inturn connects to a loadcell so the arm is pulling on the loadcell.

Now to take a sweep measurement of this, you would i imagine read a some form of rpm signal, and you do that like 30 or 60 times a second. And control the braking action on the gearpump by basicly making it  harder to pump oil through an orifice. I imagine this could be hooked into a micro controller that reads the torque and rpm sensor and adjusts the brake by means of actuating a stepper motor or something and then just read the signal from a serial connection on a pc.


Am i completely off my rockers?

redshift:
Neo, show this to your friend.  http://dtec.net.au/Inertia%20Dyno%20Design%20Guide.htm
What engine does he want to test? Let me know I maybe able to help.
Dave

NeoTech:
Ah well we build drag racing cars basicly. So it would be Bigblock chevy V8 engines, at around 1000-1200hp and 900-1400lbs/ft.

redshift:
Mmmm, a little different to the 6 - 30 bhp Kart engines I pay with. So I cant be of help but would be very interested in the solution you come up with. Eddy current or water brake? Water brake looks more like a possible solution at that level of power. Have you any pics of the vehicle that the engine is used in?
Dave

NeoTech:
That motor sits in this car atm; http://www.roughedge.se/blogg/wp-content/uploads/2014/06/20140619-184902-67742825.jpg

And are awaiting fuel injection and a new rear axle cuz i shot the 12 bolt gm axle to hell this summer..  *wiiih* And with the multipoint fuel injection i hope to find the last bit of power out of it.

I am looking at waterbrake solutions now, it all seems like a damn hassle tho, how would one control the inflow of water in relation to the RPM and at the same time have it to be exact enough to retard the motor enough for a controlled rpm curve...  The best would be to find 2 telma 1700lbs, 6000rpm eddy current brakes froma lorry.

The benefits of water or eddy current brakes tho is that you can self learn the engine efi under simulated load and create the complete map without getting on the road at all.

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