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Acceleration runs  

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(@2teng)
Member

I'm trying to understand the limitations of acceleration runs using an eddy current brake. The application will be motorcycle and most likely an engine Dyno not a chassis Dyno. 

 

Is there a practical limit on the acceleration rate? For instance if I wanted to get a 4th gear power run say over 10s is that feasible?

 

Logically i imagine 2 approaches... Set the Dyno to accelerate at a nominal rate...say 800rpm / second

Or set the Dyno to maintain a constant torque and get a resulting acceleration. Emulating an inertial Dyno.

 

Is there another way ? 

 

Thanks for any responses

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Posted : 24/01/2020 12:12 pm
(@walter)
Member

Hi! yes, you can use RPM CUrve, you can put time of the ramp test. ive been using that mode since i got Yourdyno +2 years and worked good since all test i did, took 12 seconds...just recently tested Power sweep mode, since i had recently 2 "problems" testing a diesel cars, found the error there, right now im using power sweep and runs really good. you can try to calculate total time of the test using power sweep too..but maybe it will not works good if you use big brakes.

 

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Posted : 24/01/2020 1:27 pm
(@2teng)
Member

Thanks for reply....very useful. Have you found the rpm curve to produce repeatable results?

 

When you say power sweep what is the Dyno doing? Constant torque through the power range or something else?

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Posted : 24/01/2020 3:24 pm
(@walter)
Member

Yes, in my hub dyno, difference if all correcctions are the same, including the car, is less than 0.1hp. last test that got results like that was BMW 193hp, reading 193.17hp and other 193.60 or so.. very accurate if everything is ok.

Power sweep is very similar to RPM Curve, just less things to put..id say it's better for ramp test.

you introduce starting RPM, time waiting for the dyno to get rpm stable and end rpm of the test. you can configure the "time" of the test by setting up rpms x seconds.

In RPM curve, you really can do the same, put starting rpm, you put the time  and end rpm for test but different way, rpm curve will works for other test too like make a "curve" for acceleration and desaceleration while you are a full throttle or something like that, power sweep is good for ramp test only.

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Posted : 24/01/2020 3:57 pm
(@2teng)
Member

Excellent information...thank you...👍

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Posted : 24/01/2020 4:15 pm
(@2teng)
Member

One question...are you able to produce an average run using previous runs?

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Posted : 24/01/2020 4:24 pm
(@walter)
Member

Not really, there isnt any way to do yet in Yourdyno, anyway you can use math for calculate it 😀

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Posted : 26/01/2020 12:56 am
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