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Use of MATLAB for CVT Tuning

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Vladmir123 View Drop Down
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    Posted: Sep/19/2012 at 3:22am
We're currently making a CVT model using Simulink on MATLAB and are having trouble with choosing the parameters. we wanna include the two springs, the helix ramps and the flyweight but are having a problem when v enter the variables into MATLAB and on testing it out, we get different values on actual testing of the engine and CVT. Does anyone know how to do this ? if anyone has used MATLAB to do this, please do help us out with the model used
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sandres913 Quote  Post ReplyReply Direct Link To This Post Posted: Sep/19/2012 at 10:03am
"v enter the variables" - velocity of the sheaves? If you don't mind me asking, what method are you using to solve it? Force balance or energy balance?
I think Priyank was doing the same thing, if he doesn't post here, you might try sending him a private message about it.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Vladmir123 Quote  Post ReplyReply Direct Link To This Post Posted: Sep/21/2012 at 3:04pm
We initially thought of going with force balance but after going through a couple of posts online and talking to Priyank, we're considering energy balance. we're still not sure how to go about writing the equations and as to how many parameters to include. There's too many variables to consider. working on that
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Priyank Quote  Post ReplyReply Direct Link To This Post Posted: Sep/25/2012 at 3:19am
It's difficult, time consuming, and might seem way off the actual values, but with a few iterations and a change of values here and there, you'll get what yo want !
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sandres913 Quote  Post ReplyReply Direct Link To This Post Posted: Sep/25/2012 at 9:44am
Originally posted by Priyank Priyank wrote:

It's difficult, time consuming, and might seem way off the actual values, but with a few iterations and a change of values here and there, you'll get what yo want !

Definitely agree on the time consuming part. Did you end up using energy balance or force balance? My force balance model is done up to the torque sensing cam, which I haven't had a chance to model yet. I can already see a few problems with the force balance method, but it might look better once I measure my spring constants and weights.

Also, how did you treat the secondary spring? I was thinking of assuming that spring was purely in compression, neglecting the torsion portion of it.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Priyank Quote  Post ReplyReply Direct Link To This Post Posted: Sep/30/2012 at 11:53pm
I started with force balance, but it didn't just feel right. I feel energy balance is a more holistic thing; force balance just makes things difficult and less accurate.
But overall too, this complete software program with tuning would not be an exact picture.
We have to, HAVE TO, run millions of test. there's a lot of calibration and tweaking in the final function.

And although the thing looks pathetically difficult, it's where the fun begins :D
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sandres913 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/01/2012 at 10:04am
Yeah that's what I figured. Oh well, I was getting ready to scrap my force balance steady state excel sheet anyway. Finally got Matlab on my laptop Smile

I would argue the bit about force balance being more difficult, maybe not the less accurate part though. It could make things so much simpler than they need to be. K.I.S.S. :P
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Priyank Quote  Post ReplyReply Direct Link To This Post Posted: Oct/02/2012 at 1:29am
Force balance is obviously easier to imagine and model, but it just does not give the right values, i don't know why :(
So, i left it and went for energy.

Which CVT are you currently working on ?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sandres913 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/02/2012 at 12:12pm
I was working on CVTech, but things change and bing bang boom we might be getting the Gaged GX-9. So I might make the program extreeeeeemely modular, possibly splitting the thing up so it references sub-routines and selects either a roller weight or block weight program dependent on program settings, for future generations.

Still not looking forward to analyzing that secondary cam again. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Priyank Quote  Post ReplyReply Direct Link To This Post Posted: Oct/03/2012 at 11:46am
I have heard so much about the Gaged GX series. If it wasn't about the affordability and ease, i would have loved to go for it.

How is it different from the good ol' CVTech ?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Soccerdan7 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/03/2012 at 12:42pm
much lighter
different ratios
less overdrive
primary has independent ramps and weights to tune each separately
secondary is rollers instead of sliders and has a fully caged helix (on both sides of roller) so it doesn't slam back on backshifting
tons of part options for ramps, helixes, springs, etc
quality / workmanship of parts is way higher
double cogged belt is much nicer and more efficient
can make your own weights since the shape doesn't matter


You can manually customize the CVTech to do about half to 2/3 of this list but it still won't be competitive in terms of weight and quality. It is expensive, but you get what you pay for and Bill will help you out and recommend parts to customize it for you.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Priyank Quote  Post ReplyReply Direct Link To This Post Posted: Oct/03/2012 at 12:46pm
:(
I want a gaged now !!

I was about to ask this query...

My CVtech has a unique shapes for the weights, and althgough i can find the weight i want, as calculated by my program, no way can i manufacture them, simply because of the shape issues.

CVTech is kinda limited to work with. At the max, springs can be changed, weights made lighter...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Priyank Quote  Post ReplyReply Direct Link To This Post Posted: Oct/03/2012 at 12:48pm
I can do the fancy programming stuff, but i am unable to find a way to manufaccture them...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DomUL Quote  Post ReplyReply Direct Link To This Post Posted: Oct/03/2012 at 12:58pm
Gaged is definetly a more refined option! However the amount of parameters that you can tune with a CVTech is still way enough for you to tune all year long and still have much more to do (I can relate by all my sleepless nights!). I would say the difference of ratios and the price are the big deal between the two. But as Danny mentionned though, Gaged got many advantages performance wise!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Priyank Quote  Post ReplyReply Direct Link To This Post Posted: Oct/03/2012 at 1:00pm
Alright...let me perfect my CVtech first :)
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Originally posted by Priyank Priyank wrote:

:(
My CVtech has a unique shapes for the weights, and althgough i can find the weight i want, as calculated by my program, no way can i manufacture them, simply because of the shape issues.

The way I thought of making them was to take the material to a mill (or CNC mill if available) and do the rounded top first, then flip it down, machine it to a rectangle, then flip it again and machine the bottom radius. This is a thought though, haven't done it.

We don't actually have the Gaged yet, we're going through the process of acquiring it.

Like what has been said, the price is generally the killer. But if you need help justifying it, just think of it like this. The CVTech has its own version of adjustability, what with comparatively complex weights, custom springs and only one OEM secondary helix option. The Gaged is fully modular, the weights are fairly easy to machine, the parts are all available for replacement/upgrade, and the biggest thing is that Bill actually attends the competition, which can be invaluable in a pinch or to simply talk to the man that made this thing. The amount of support and customization offered by the Gaged means you can use it for years down the road and remain competitive. $200 CAD every year or $1000 USD up front plus minor maintenance/upgrade. Now if you keep your cars together year-to-year, CVTech might still be okay, or at least an option to keep those cars running and just put the Gaged in the new cars.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Nick914 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/03/2012 at 1:09pm
Cue I got from a CVtech guy: a 275g mass with up to 1" hole in it covers a wide range of mass and still works fine
Nicholas Lefebvre

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Soccerdan7 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/03/2012 at 11:34pm
Originally posted by Priyank Priyank wrote:

:(
I want a gaged now !!

I was about to ask this query...

My CVtech has a unique shapes for the weights, and althgough i can find the weight i want, as calculated by my program, no way can i manufacture them, simply because of the shape issues.

CVTech is kinda limited to work with. At the max, springs can be changed, weights made lighter...

Yes, the Gaged is pretty awesome but it takes a while to try and get it right. We had problems since our old cars had different gearbox ratios and were 80 lbs heavier so we could not start seriously tuning until the new car was drivable.

You can get creative with adding or removing CVTech weight while still using the same plastic pieces to control sliding. It is easier to drill out the existing weights, but you can add it back. How different is your theoretical weight from the normal CVTech weights?

You can also change more than just that on the CVTech. We converted the secondary sliders to rollers, made our own multi-angle secondary helix and replaced the huge steel dome on the primary with a carbon piece in addition to endlessly messing with weights and springs. FEI has done a similar amount of work in terms of modifications and I have no idea what Laval, ETS, and Sherbrooke do, but it seems to work well.

Also, when in doubt gear higher than expected as you can get great top speed performance (like we did in 2010 or Laval in recent years) without much of a tradeoff in acceleration performance.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Priyank Quote  Post ReplyReply Direct Link To This Post Posted: Oct/05/2012 at 12:25am
About the gaged, i sent them a mail for something lesser.
$825, is a butt load, when it comes to my local currency. Let's see what they say.
I would love to have it.

And yes, CVTech is enough to work with for a fresh man like me, but this is ginna be my last, so just want to push it a little.

And i wouldn't become that experimental with my CVT. No one sells them in India, and god forbid, if the CVT doesn't work properly afterwards, I'd gotta kill myself :p
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Priyank Quote  Post ReplyReply Direct Link To This Post Posted: Oct/05/2012 at 12:28am
I have to add some weight, don't exactly how much.
Adding is gonna be problematic.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Nick914 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/05/2012 at 8:00am
300g masses exist, but might be harder to find (available in europe)
There are other things you can do instead of using heavier masses (see clutch tuning handbook)
Just sayin'
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sandres913 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/05/2012 at 10:33am
What springs are you using? And why do you want to add weight?
Shaun
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Priyank Quote  Post ReplyReply Direct Link To This Post Posted: Oct/05/2012 at 9:33pm
Need to make my CVT more sensitive to the change.
Increasing masses, i would make it shift at a lower RPM.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote RonGeorge Quote  Post ReplyReply Direct Link To This Post Posted: Oct/06/2012 at 6:57am
I hope you make such a GUI for Gaged clutch.  I recommend that the OP make better use of a short development time that is typically given in Baja to tune the vehicle on the field.  Whether its CVtech or Gaged, I think the number one cause of clutch to clutch performance variability is the rubber belt and since these devices are friction limited, you want to try different combinations and see what works best. MATLAB will spit you results based on your assumptions and the model, the real world may tell you something different. So then, you must understand what is the real value of a computer simulation and whether the cost/time of developing the program has any perceivable impact on field performance. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote andrewg Quote  Post ReplyReply Direct Link To This Post Posted: Oct/07/2012 at 3:03pm
can a custom made cvt be used in competition, or does a commercially produced cvt have to be used?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DomUL Quote  Post ReplyReply Direct Link To This Post Posted: Oct/07/2012 at 4:36pm
You can use everything you create for your powertrain (CVT and Transmission). Just be sure you have the proper guards and you'll be ok.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote andrewg Quote  Post ReplyReply Direct Link To This Post Posted: Oct/07/2012 at 9:22pm
thanks for the info. also does anybody have any insight on making a cvt have forward and reverse?

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Soccerdan7 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/07/2012 at 9:47pm
Originally posted by andrewg andrewg wrote:

thanks for the info. also does anybody have any insight on making a cvt have forward and reverse?


Based on this thread and your other one, I HIGHLY advise you to research CVTs and the competition in general first before trying to design your own CVT. The rules are very clear about this sort of stuff and you should read them front to back several times if you are still having questions like this.

A CVT (in this context) is simply a single stage reduction with a range of gear ratios. All off the shelf items require additional reduction in the form of a gearbox or chain reduction, and that is where you incorporate the reverse gear. The CVT simply spins the same direction as the engine output.

Designing a CVT is a huge undertaking and only 3 or 4 teams have had them at competition (Michigan, Michigan Tech, UMBC, anyone else?) and a few other have attempted it or have it in the works based on rumors I have come across. You need to exhaust the options of your stock CVT, be comfortable tuning it and understanding how it works, make major modifications with successful results and have solid reasoning before starting this project. Off the shelf CVT's provide you a great platform to work from and the gains of a custom one are rather small, so you need to be a pretty advanced team with specific improvements in mind to make this worthwhile.

I may sound a bit condescending in this post, but you really need to do some more research.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote andrewg Quote  Post ReplyReply Direct Link To This Post Posted: Oct/10/2012 at 12:06am
Soccerdan7
 
thanks for the feedback also, where in the rules does it talk about drivetrain/tranmission and what you can a cannot have because I have read the rules many times and still have not come across it

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Post Options Post Options   Thanks (0) Thanks(0)   Quote sandres913 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/10/2012 at 12:11am
Originally posted by andrewg andrewg wrote:

Soccerdan7
 
thanks for the feedback also, where in the rules does it talk about drivetrain/tranmission and what you can a cannot have because I have read the rules many times and still have not come across it


That's because it doesn't exist. As long as all power comes from the Briggs, they don't care what method you use to transmit that power, so long as it's guarded in a safe manner such that rotating parts cannot fly apart and injure someone and nobody can stick their hand in and lose a finger
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Soccerdan7 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/10/2012 at 10:09am
Originally posted by andrewg andrewg wrote:

Soccerdan7
 
thanks for the feedback also, where in the rules does it talk about drivetrain/tranmission and what you can a cannot have because I have read the rules many times and still have not come across it


If it isn't covered in the rules, you can do whatever you want. My point is that if you have read the rules "many times" you should realize this. And if you are unsure about something like this, you should probably use the off the shelf item to start with to get a car working and tuning and improving. How else will you know what you want out of your custom CVT?

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Akron 1998 to 2004 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/10/2012 at 5:08pm
Originally posted by Soccerdan7 Soccerdan7 wrote:

Originally posted by andrewg andrewg wrote:

Soccerdan7
 
thanks for the feedback also, where in the rules does it talk about drivetrain/tranmission and what you can a cannot have because I have read the rules many times and still have not come across it


If it isn't covered in the rules, you can do whatever you want. My point is that if you have read the rules "many times" you should realize this. And if you are unsure about something like this, you should probably use the off the shelf item to start with to get a car working and tuning and improving. How else will you know what you want out of your custom CVT?

The rules focus on safety issues and are deliberately not specific on design options so as to allow engineering creativity. 

Do you want to design a CVT because you think available models are deficient or do you just not think this competition is challenging enough?

If you think available CVTs aren't sufficient, what is it you'd like to have on a CVT wish list?

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Akron 1998 to 2004 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/10/2012 at 5:14pm
Originally posted by andrewg andrewg wrote:

thanks for the info. also does anybody have any insight on making a cvt have forward and reverse?

Mount the secondary CVT pulley to a planetary gear box.  Lock different portions of the planetary system to achieve forward or reverse.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Priyank Quote  Post ReplyReply Direct Link To This Post Posted: Oct/18/2012 at 11:54pm
This dude is taking things to a new level.

CVT's in the market are amazing enough to rely on them. I've been working on CVT's for a long time now, and the gurus here have guided how to tame my CVTech, leave alone a gaged one, that is an entirely new level to work upon.

Are you suggesting that you wanna transcend gaged as well ?
CVTech is enough a challenge for me :/
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Priyank Quote  Post ReplyReply Direct Link To This Post Posted: Oct/18/2012 at 11:56pm
On that note, can anyone tell me how well a Jeffco gearbox works ?
I mean, is it good enough to spend that butt load of money on that ?
RPM is too expensive :(
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Akron 1998 to 2004 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/19/2012 at 12:51pm
Originally posted by Priyank Priyank wrote:

Are you suggesting that you wanna transcend gaged as well ?
CVTech is enough a challenge for me :/
 

I think you guys are giving Gaged CVT too much hype.  Definitely a well built piece of CNC pornography.  However, it appears to have a high ratio of just 0.75:1 (correct me if I'm wrong).  That seems ideal for a flat track junior dragster but I think Baja needs more for a down hill run.

 

The CvTech High 0.43:1 seems like too much overdrive.  Not sure if its usable.  The efficiency would definitely be low at that ratio.

 

I think one of the Comet 700 series is optimum (easily tuned with available parts):

770 high 0.76:1

780 high 0.69:1

790 high 0.54:1

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Priyank Quote  Post ReplyReply Direct Link To This Post Posted: Oct/19/2012 at 12:55pm
Never reached 0.43. Stayed around 0.6
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DomUL Quote  Post ReplyReply Direct Link To This Post Posted: Oct/19/2012 at 1:01pm
Originally posted by Akron 1998 to 2004 Akron 1998 to 2004 wrote:

 

The CvTech High 0.43:1 seems like too much overdrive.  Not sure if its usable.  The efficiency would definitely be low at that ratio.

 

 
We are using most of this high ratio so it's definetly possible to use some of that overdrive. Sure the efficiency will drop near the end but if you can reach it you'll have some interesting top speed! Illinois 2011 and Wisconsin 2012 were pretty fast (same as Washington this year and Rochester too) and we acheived interesting speeds
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Soccerdan7 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/19/2012 at 1:34pm
Originally posted by Akron 1998 to 2004 Akron 1998 to 2004 wrote:

 

I think you guys are giving Gaged CVT too much hype.  Definitely a well built piece of CNC pornography.  However, it appears to have a high ratio of just 0.75:1 (correct me if I'm wrong).  That seems ideal for a flat track junior dragster but I think Baja needs more for a down hill run.

 

The CvTech High 0.43:1 seems like too much overdrive.  Not sure if its usable.  The efficiency would definitely be low at that ratio.

 

I think one of the Comet 700 series is optimum (easily tuned with available parts):

770 high 0.76:1

780 high 0.69:1

790 high 0.54:1


The Gaged is overpriced and overhyped, but small size, weight, and high(er) degree of tunability are very nice. You could run a CVTech out of the box and it would be decent for most cars and then there's really onles 4 things you can change unless you start making custom components. The Gaged has a few more and the lower weight and friction make it perform better. We didn't have a problem with the lower top end last year as we were pretty quick in Auburn (other issues slowed us down a bunch in Wisconsin), you just need to adjust the rest of your gear reduction accordingly.

I don't know much about the Comets but several good teams have run them in the past, so they must be pretty good.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Akron 1998 to 2004 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/19/2012 at 2:18pm
Originally posted by DomUL DomUL wrote:

 
We are using most of this high ratio so it's definetly possible to use some of that overdrive. Sure the efficiency will drop near the end but if you can reach it you'll have some interesting top speed! Illinois 2011 and Wisconsin 2012 were pretty fast (same as Washington this year and Rochester too) and we acheived interesting speeds
If there is top end you're not using, that means you could have had more low end for tractor pull.  However, if its not broke don't fix it.  You seem to be doing fine.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Soccerdan7 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/19/2012 at 2:22pm
Originally posted by Akron 1998 to 2004 Akron 1998 to 2004 wrote:

  You seem to be doing fine.

Understatement of the year.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DomUL Quote  Post ReplyReply Direct Link To This Post Posted: Oct/19/2012 at 6:07pm
Originally posted by Akron 1998 to 2004 Akron 1998 to 2004 wrote:

If there is top end you're not using, that means you could have had more low end for tractor pull.  However, if its not broke don't fix it.  You seem to be doing fine.
 
Yes you are right... I was too much focused on the top speed in my answer. Baja is a lot about acceleration and reacceleration in many difficult conditions so you should not neglect the low end. Top speed will only serves you well in long straights which is pretty limited (maybe once a lap) and relatively long downhills.
 
Since i'm on the project, we've always tried to have an all around car that can perform well in all conditions so we tried to have a right balance between high end and low end. This can be done in some ways and surely with CVT tuning. In the past few years (hopefully in the future too) we were among the fastest cars but i'm sure there is plenty of ways to get Baja cars notably faster.


Edited by DomUL - Oct/19/2012 at 7:25pm
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http://minibaja.gmc.ulaval.ca/
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ballast Quote  Post ReplyReply Direct Link To This Post Posted: Jul/05/2013 at 3:59pm
I have worked with CVTech for a year with just cones and stopwatch. Now I am considering to try Matlab codes to get the numbers for tuning. I can pretty much understand the force balance method; i.e the amount of centrifugal force required to overcome pretension and then the sideforce and so on. But i read you guys saying that energy balance is superior to force balance. But there is where my problem begins. As i understand it, the energy produced in the engine appears at crankshaft, stabilized by the flywheel, transmitted to the primary clutch and so on till wheels. 
But I don't know where to start the energy balance. Is it the energy required by the flyweights to overcome the strain energy stored in the springs? In that case how much energy is transferred to flyweights? I don't know if I am even speaking sense.I can't figure out where to begin from...

Sorry. It went too long. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote km2014 Quote  Post ReplyReply Direct Link To This Post Posted: Jul/05/2013 at 7:36pm
Hey, guys! I am currently working on a force balance model of the Gaged GX9. I'm trying to get a feel for the sort of thing other Baja people have done.

For the people who said that the force model was inaccurate, how detailed were the models that you had? Did they include belt stretch and belt slip? Did they use the Coulomb friction model or a more detailed model? Tight and slack belt side tension? I am not trying to criticize or anything, since some of these factors are really nitpicky. I am just curious as to the extent the modeling has been done. The work that I am doing is for an undergrad thesis rather than for the team specifically, so I am trying to include as much as possible.

Like I said, I am using the force model. The sources (v-belt in general and CVTs specifically) I recall seeing all use force balance as well. Could anyone tell me a bit more about their energy balance, maybe in a PM? I'm not looking for specifics, obviously, just general methodology.

Thanks!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote zglazer Quote  Post ReplyReply Direct Link To This Post Posted: Jul/05/2013 at 8:49pm
Originally posted by ballast ballast wrote:

I have worked with CVTech for a year with just cones and stopwatch. Now I am considering to try Matlab codes to get the numbers for tuning.
If your objective is to use simulations from a mathematical model of the CVT to replace vehicle testing for tuning purposes, you're on the wrong track. The results you get from simulations will be nowhere near as meaningful as what you will get from actual testing on a baja. Your time would be much better spent designing and building a set of photogates so you can get more accurate values from your testing.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ballast Quote  Post ReplyReply Direct Link To This Post Posted: Jul/06/2013 at 6:44am
Originally posted by zglazer zglazer wrote:

If your objective is to use simulations from a mathematical model of the CVT to replace vehicle testing for tuning purposes, you're on the wrong track. 

Really? I think I don't believe so strongly in that statement. Yes, simulation is a tedious process to get it right. But when you are tuning with a stopwatch, and get undesirable results in a test, then you ll be lost in darkness with millions of variables a CVT depends on and you have to run the entire logic in your mind to get the next number for tuning. Matlab simulation saves that trouble; it runs the logic for you and you can get the next number without much trouble.

Guys anyone who got the Matlab thing right, give me an idea/the basic assumptions to start coding an Energy balance model. Or is energy balance even required??
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Post Options Post Options   Thanks (0) Thanks(0)   Quote zglazer Quote  Post ReplyReply Direct Link To This Post Posted: Jul/06/2013 at 12:16pm
There are only a few different parts you can change in a CVT (especially few if you're using the CVTech rather than the Gaged which is much more configurable), and it is not especially difficult to run through the full range of possible setups with the parts you have. With the MATLAB simulation on the other hand, you may not ever be able to get it to a state where the results it provides are consistent with the results you get from running the same setups on your actual car, in which case the simulation is completely useless to you.

MATLAB simulation is not a replacement for testing, period.
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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 12:58am
Hello guys..
I am new to the competition and was trying the simulation approach towards cvt tuning.
I have been working with the car for some time now but I'm having some problems with the driveline model.
The variable ratio transmission model does not use any parameters such as the weights , cam and spring profile.Is there any way to add these to the simulation model.
Also I have attached the pic ...please help 
uploads/4671/cvt.PNG
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