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rd94 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rd94 Quote  Post ReplyReply Direct Link To This Post Topic: CVT
    Posted: Mar/01/2018 at 10:14am
I am new to the competition and want to get more knowledge about cvt tuning.
I have gone through the aenn clutch handbook but I'm still not convinced on how to approach the tuning in real life.
Can anyone give some detailed steps/procedure to carry out tuning?
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Andy.R View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Andy.R Quote  Post ReplyReply Direct Link To This Post Posted: Mar/02/2018 at 2:08am
Simply put, start playing around with settings. You will learn much by changing weights, preload, helix angles, ramp angles, etc. Once you start changing variables, you can see what is affected by those changes. Get RPM data from both the primary and secondary to quantitatively tune, or even acceleration times & a cheap camera if you are on a limited budget. I'll give you a starting hint, primary weights are the first thing to tune and somewhat dial in. 

Best of luck!!Smile
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Bantu View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bantu Quote  Post ReplyReply Direct Link To This Post Posted: Mar/06/2018 at 10:38pm
Hellow people. I have a Design project whereby I gotta optimize a mini-baja CVT for better speed and hill climb. Any ideas as to where do I start doing this optimization?
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Andy.R View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Andy.R Quote  Post ReplyReply Direct Link To This Post Posted: Mar/06/2018 at 11:18pm
Really ..... please read what I wrote in the last message. 
Andrew Raudabaugh
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rd94 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rd94 Quote  Post ReplyReply Direct Link To This Post Posted: Mar/12/2018 at 1:03am
Thanks buddy..
I have a much better idea now and have decided on using a simulation model using MATLAB to start things up.
Also I tried using hall and ir sensors for rpm measurement of the pulleys but they also give a considerable amount of error.
What technique did you use for rpm counting?

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Bantu View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bantu Quote  Post ReplyReply Direct Link To This Post Posted: Mar/14/2018 at 1:44pm

My name is Bantu Keyizana residing in South Africa. I am a student at Nelson Mandela University (NMU) doing my BTech in Mechanical Engineering. In my Design Project, my lecturer asked me to optimise the CVT of the Mini Baja for better performance in acceleration event and hill climb event. I am not given any set of requirements/specification. Therefore I am expected to do my own research and make up my own requirements/specification. Please help me with the following questions with regards dynamic events of the mini Baja competition.

 

1. What was the least weight of the entire Mini Baja  in the previous mini Baja competition excluding the driver?

2. How long was the track for linear acceleration event?

3. What was the least time achieved by the Baja during the acceleration event on that specific track?

3. On Hill climb event, what was the steepest inclined? 

4. How long was the inclined track? 

5. What was the least time achieved by the Baja during the hill climb event on that specific track?

 

 

Regards

Bantu Keyizana

0739031847

 

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RLM View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote RLM Quote  Post ReplyReply Direct Link To This Post Posted: Mar/15/2018 at 7:07am
- please review past results for dynamic times. these results are available online with a little research.
- all baja vehicles weigh different amounts. anywhere in the range of 270# to 800#
- track data is not typically disclosed. I can tell you that the hill climb is steep and varies in length from event to event. 
- the accel run also varies but is typically between 100' and 150', though the surface it is performed on varies greatly. 

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rd94 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rd94 Quote  Post ReplyReply Direct Link To This Post Posted: Mar/20/2018 at 11:36pm
Has anyone tried a simulation model for CVT Tuning?
How accurate has it been to the actual testing values?
what software did you try it on?
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brianballewsr20 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote brianballewsr20 Quote  Post ReplyReply Direct Link To This Post Posted: Dec/10/2019 at 10:14pm
I built a very complex model in matlab as part of my thesis in 2016. I had no experimental data to valid the model though. Took several minutes to run a 10sec simulation, even when using the MXfunctions to convert to C code. Many of the problems are based on measuring/defining model perimeters and boundary conditions.

https://scholarworks.uark.edu/etd/1375/
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Iron Man Quote  Post ReplyReply Direct Link To This Post Posted: Feb/24/2020 at 12:31am
Matlab is essentially useless for theoretically calculating optimal tunes, believe me I've tried and failed. Get a tiny tach and watch it as you accelerate. Change the ramp angles, weights and springs in the primary to keep your rpm as high as possible without hitting the rev limiter. More spring force=more rpm, less weight=more rpm, steeper angles=more rpm.
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