How a Continuously Variable Transmission Works
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- Опубліковано 20 чер 2023
- Here's a look inside a continuously variable transmission and how it works!
A continuously variable transmission uses a steel push belt to transfer power from an input variator to an output variator. The diameter of the belt's input and output shaft varies, which determines the drive ratio.The variators are hydraulic cylinders that have a cone shape to the pulley section that interface with the belt. When fluid is added, the belt is adjusted to ride on a larger diameter. Meanwhile, fluid is released from the opposing variator, allowing the belt to ride on a smaller diameter. Both variators must be adjusted together for belt tension to be retained.
A planetary gear set on the output variator allows a change in direction for reverse gear, as well as a two speed step to increase the range of the CVT. Similar to an automatic transmission, a valve body controls how much fluid is applied to the variators, planetary clutches and torque converter.
Typical failures with CVT's include overheating - which is likely due to too much load on the unit from driving uphills, overloading the vehicle, worn fluid or towing conditions.
Furthermore, if belt tension cannot be retained, the belt will slip and shudder. Finally, since the belt itself is fragile and made up of hundreds of pieces, any minor alignment or over application of torque can cause it to catastrophically disintegrate.
he CVT in this video is a Jatco CVT-7 unit from a 2020 Chevrolet Spark with only 2000km on it. The vehicle was in a collision and the engine and transmission were working units when removed!
This is the Camera I use:amzn.to/3oaRcZX (US)amzn.to/3KWQ2uU (Canada)Link to Etsy shop where you can purchase speedkar99's brother's socks, t-shirts or hoodies: www.etsy.com/ca/shop/Speedkar... on Instagram and Tiktok / @speedkar9speedkar99 on Facebook and Linkedin: / subscribe for more videos just like this:ua-cam.com/users/subscription_... - Авто та транспорт
It's amazing you can transmit any power at all with such a small surface area between cone and belt. I know CVTs are usually stuck on low power engines, but I'm surprised they don't just slip the moment you give it full throttle.
I agree but think of the hydraulic pressure in the variators squeezing on that belt!
Oil pump boost preasure from 5 bar to 50. Cruising speed between 0-15 kW can be 7 bar. Kickdown will first boost oil preasure than engines throttle. Cvtz50 app and obd2 are like movie for me while driving. Locking torque convert are also depended of throttle, hills, mass, oil temperature.... Interesting machine.
The Throttle pedal controls only the engine, gearbox reads engines parameters, gyroscope, speed and insertion. Downhill is also interesting, it revs higher to steepest downhill to keep the speed....
Mine slips occasionally in low gear trying to accelerate, very annoying. Getting it looked at soon.
@@richardoneill7291 slips or adjusting ratio? be sure or it will be expensive. buy obd2 and CVTz50 app
I'm daily driving on a Honda CVT with over 112K miles and zero issues. Fluid changes are important! I do floor it from time to time for fun, and I'm not babying it on the highway passes by any means, but my engine peaks at under 190 HP. I've learned from the tuning community the transmission can handle up to roughly 250 HP, but I don't have the money to verify that. As far as torque tolerance in general goes, though... More modern CVT-based setups often have a single-gear automatic for launching the car from a stop, to reduce the load on the CVT from the sudden massive torque of moving a stopped car. I don't have that on mine, since it's a 2013.
What shocks me about the metal belt CVTs is that there aren't any visible notches or anything on the cones for the belt to grip, despite the fact that belt slippage could potentially kill the transmission. I've also seen a teardown vid of a Honda CVT from a CR-V. It has some similarities and differences. In that video, the belt had slipped. The only visible indication of how it had failed was some scratching on one of the cones, as the other cones had nice, evenly machined surfaces. No debris or anything.
What a pleasant guy to listen to with great love to his brother and nice sence of humor not mentioned good knowledge of cars. Thanks 👍
Ikr he’s like the chill alternative uncle you’re seeing 2 times a year and always tells cool relatable short-stories
You are welcome. Glad you like my videos.
Early CVTs were quite notorious for their reliability issues but newer ones aren't really that bad. Where I live, the first Honda City and Toyota Vios with CVTs have passed their 10-year mark and are still running with no issues. What can really put you off when driving a CVT is how it feels.
Jatco CVT are still crap. I'd never buy a Nissan with a CVT
AISIN K311 K313 FTW
HATE the way CVTs drive. Sloppy and unpredictable
I agree, Nissan made a bad name for CVTs but there sure is alot of them out there!
@@markgriz I have a 2010 Alitma 110k and I've been changing the fluid every 30-40k so far so go. That's the only way they will last and without hard accels.
Love your videos! My dad was a mechanic, so I enjoy the content. And your detail. Also, thanks to your brother for his clothing!
You are a Genius! Every part has a different name and you named them all! Fascinating video.
Amazing design and engineering! That double planetary gear setup fascinates me. To conceive of that, and then actually build it, is WAY beyond my pay grade!
Excellent video! Very informative with a few sprinkles of your brother's clothing jokes amongst a few others. I sometimes get mesmerized when you unbolt everything with your editing magic. Excellent narration during your dismantling process. Just wonderful. Well done sir. 👍
Last year, I went to the DAF museum in Eindhoven, The Netherlands, where the CVT originates. It was first called “Variomatic” transmission and used in the first DAF cars such as the 600 (about 1959) and in later models like the Daffodil and 33. Many mechanicals of the drivetrain in those cars were external not like CVTs and differentials of today. Really worth a visit. They have old open sectioned CVTs on display.
Excellent and interesting video, as always, on a modern CVT. Really interesting stuff. Thanks for the tour!
Thank you for making this video. That was an awesome explanation of a very complex piece of machinery. Even I could kind of understand how it worked after watching your video.
Amazing explanation. Even if I watch this video 20 time I'm not be available to put that transmission back together, so many components, but I understand better the whole concept, thanks for sharing this video.
I'm always amazed on how much you know about how things work. You are pretty darn good at what you do
Thanks. I do a little research but the best way to learn is to tear things down with your own hands
Awesome content! This is why I have notifications on for this channel!
Thanks for subscribing and watching!
I remember in the early 1980s someone heard my brother was a brilliant engineer and gave him a bright orange, low mileage Volvo 66 (a rebranded DAF) with a locked transmission to fix, they said if he could sort it out he could have it for free, because absolutely nobody could figure out what the problem was and why it never ran right, not even the main dealers. He puzzled over it for weeks, took things apart and studied them, then rebuilt it and observed it working, trying to resolve various problems. He had me listening to vacuum pipes while he worked the controls until one day a pipe nearly sucked my brains out and he suddenly understood how it worked! After drawing diagrams on paper and retiring to bed he was up early next day and had it working perfectly within a few hours. That car then ran faultlessly for years and he even designed an electro mechanical modification so that he could manipulate the gearing at will by flicking a switch. He said at the time that he had various ideas on how to improve it and that he believed that one day most cars would have cvt transmissions. Shame he lost his way later in life when he decided he was going to be a famous pop star. Don't know what eventually happened to the car and alas these days we don't speak, because as you may have gathered, he's a nutter!
Nice brother
This speaks to my inner child when I took EVERYTHING apart.
Thank you for your service, little blue glove.
I love taking things apart just to see what's inside.
I'm not much of a person to put it back together though.
I love the use of family members clothing and the environmentalism. Hilarious. Keep up the great work!
Thanks!
Environmentalism is key here
Clean up after your mess
And take car parts apart before scrapping them, making best use of them
The best explanation I've ever seen... Thank you...
WOW THANKS FOR A GREAT VIDEO!!! right to the point no drama. Great info I wished all youtube vids were like this one thanks again love it.
Glad it was helpful!
I just did a CVT flush the other day on my Civic🙌 i do it every 30k miles and thankfully still running good. My Honda has 108k miles
I love your vids they are very educational and informative.
and funny!!
@@CyriacS I'm drinking my coffee and he says since his brother is married he wont be needs his dress pants. I had to clean up my coffee mess.
I love you
@@rayc.8555 Cleaned up with dress pants too?
Whoops!
Great video. I learned a lot. Thank you
Great video. Thank you.
You are welcome
Great content as usual Speed
Mind blowing engineering 😮
It's amazing
Nice explaining... Good work
Than
You are so good at your craft bro ! Learning so much from you as an upcoming car UA-camr !
Thanks...what about me makes it good?
@@speedkar99 how you dive into details and articulate every system in the engine set up feels like a physics class practical
Kinda amazed at 1. How rotational motion is channeled here and there by all the engineering time & machined components; gears, fluid, clutch disks, electronic/electrical gizmo's plus a metal belt makes something move with less green house gases overall. Seems like a oxymoron. 2. How you still live in a house "borrowing" or so sure "not needing" your kin's what ever. Your a peach, I laugh through out most of video on those off the wall comments. Well done! The mechanical explanation & show & tell are awesome but I think you know that. Great job.☺😆
I couldn't agree more! These devices are so complex and it's amazing to see how each one is mass produced to such a high level of prescion to work cohesively
I have a Subaru Legacy 3.6r with a CVT, absolutely love it. 250hp is not a small amount and it handles it very well.
@speedkar99 : You should have more subscribers... Great content and delivery. Keep up the good work! This is how a demonstration video should be made. I can tell you put a lot of time / effort into your videos. Thanks!
Thanks. Yes it's alot of effort, I'm glad you can learn something from it.
Please share on your network and share the knowledge! Thanks
Thank you for the brake down of that transmission my father gave me one Nissan rogue 2010 and I drive it with care and change the oil at soon I can to see how is going to be.Thanks for you videos
I really like your video style!
Thanks! More to come
Hi, your deadpan style of humor had me laughing more than usual with this one.
Oh, and I DID learn something too, thanks.
Haha
Glad you were entertained
Very interesting! In 1959 the Dutch DAF model 55 used 2 belt driven variators to skip the differential. It was the first car to be allowed to be driven by the disabled unable to operate a stick shift. We had a belt driven variator in a drill press and Italian Piaggio was experimenting with their Ciao series of mopeds. Yamaha has great success in their quad bikes with it. Going to steel belts, I had my reservation on how the oil is going to stand up with heavy loads. Personally my choice on auto reliability goes to Toyota Borg Warner units. Looking into the future, Peter Rawlinson has placed his differential right inside the axle of an electric motor. This mimics Subaru's claims of equal torque on each wheel.
Love that name.
Thanks for the information! Didn't know that
I've found the same thing, nothing makes more of a mess coming apart than an automatic transmission. Also i like when other people put words to my mechanical philosophy; I'll just take bolts out and see what happens.
Yep
Great video! I find CVT's marvelous, acceleration is very smooth and linear without the drops in power from conventional automatic or manual transmissions.
Jesus christ
@@POVwithRCpeople like you are the reason I don't shed a tear when another manual is dropped. Act like an adult and don't let other people's preferences offend you, snowflake.
until they break....
No "drops" in acceleration but lost so much power.. and money 💸
As do many other commuters, which is what these are designed for.
Good video. One of the best I’ve ever seen on u tube.
Appreciate that
The DAF 600 was the first car mass-produced with a continuously variable transmission (CVT) - the innovative DAF Variomatic system.
It's impressive how you busted 2 nuts in the disassembly process! 😅😂😅
Yeah its been a while since, so it wasn't too difficult this time around
This thing is amazingly complex.
I've never seen so many 10 mm's holding something together - glad you didn't loose your socket
Saludos desde México compa!!
would like to see a tear down of the hyundai IVT trans, from schematics i read a totally different design and how it operates.
That would be awesome if I can find one
Wow, I already kinda knew this from my little Scooter! I think most believe CTVs are more complicated / expensive than regular transmissions.
They sure might be.
I actually subscribed because of that dry phenomenal humor
Thanks!!
I run away as fast as I can when I hear CVT in a car😂
Yeah I'm disinterested
Some brands are far worse
CVT: crappy volatile trainwreck
I bought a cream puff Altima with a cvt. I wouldn’t have bought it had I known. That was 8 years and 126k miles later. I maintain the trans and don’t drive it like a rally car and feather the accelerator. Hoping for 200k
Change your CVT tranny fluid when the owners manual states and you should be good to go. Most CVT owners who cheap out and use the wrong tranny fluid usually have CVT issues........
I've got a 2014 Altima with 191,000 miles w/ original trans, I do complete drain and fills every 30k, hope this helps!
@@MrIMCP well said, most car owners dont follow the owners manual and then blame the Car brand. Change your tranny fluid its that simple.........
As long as you keep draining and filling with the CORRECT MANUFACTURER SPECIFIED CVT fluid, you should be good to go.
Nice!
At mark 15:44 you explained how the “lock up” occurs... so when that happens is when u put it in gear and you feel a bump or thump “engagement” . How would you lessen that hard engagement? And what causes to get worse?
I have a Rogue and it sometimes does that.
If the hydraulic fluid is being sent too quickly it will cause a hard shift.
That could be due to the programming but also if the clutches are worn and just slip and grab.
Fluid condition and temperature may also be factors in addition to engagement speed.
Finally check your engine and transmission mounts
Do you have a video with Honda CVT? And a new Toyota one, with mechanical first gear?
No
amazing man
I would love to see you take apart a Hyundai/Kia IVT. I have a ‘23 forte and am curious to know the differences between that and other CVTs. The IVT has a chain instead of a belt which supposedly makes it more reliable.
Thanks for sharing
Outstanding 100/100
Honestly folks CVTs are for budget vehicles and consumers who want good gas consumption, if you dont like the CVT save your coins and buy a tradition automatic or manual........
True.
Can you please do a mechanical review on the Ford Maverick Hybrid? I'm interested in this vehicle but I'm not sure how reliable it's going to be with the hybrid and CVT drivetrain.
very informative! Never seen a 2 speed auto inside a CVT, interestingu! What was the problem that rendered this 2000km car into scrap?
The car was totalled. I bought the front end
When I first got my Malibu, getting used to the cvt was like learning how to use the gas pedal all over again. White line racing L's really stacked up tho
Ok
Today is a Thanksgiving Day for me, if that makes sense. Your video is just what I needed, thank you. BTW spice cake for dessert.
I'm glad you feel better today 😃
There's no better teaching aid than a toothbrush and your brother's best dress pants.
Yep!!
Does the Daihatsu D-CVT also use the same 2 speed planetary gearset? From their marketing it looks like its a completely separate gear train that bypasses the CVT part at high speeds.
Daihatsu dual mode cvt is opposite of Toyota's Direct shift cvt
My 1969 Ski-doo Elan had a CVT too.
I suppose you kinda get used to it. I don't think I could do it that quickly, Amazing!
Nah I like fast cars. CVT not for me
Glad it worked!
Not sure about that lol
Very interesting thank you.
Glad you enjoyed it
Dude you awesome man
Thanks. You too
Am just wondering how you will replace back each part you dismantled, please come Tanzania we have Mitsubishi Outlander of ours but we don't have much mechanics even proper oils
I don't replace these parts. It's scrap
Dude how did you learn what the parts are called and what their jobs are? I mean, this is fascinating.
Lmao, you are funny as hell😂! Those small jokes make the already good video even better
Well thanks!
The Jatco CVT in my Suzuki Kizashi worked fine, sold at 140k miles. FYI: Never did a fluid change.
My car won't move when I'm drive but will move in reverse. Initially I heard a vibration and loud noise and then it stopped moving. Do u think it could be the belt?
You sound super familiar with the components. Would love to see you put it back together though. 😂 But you didn’t look like you were going to, why did you have to take it apart in the first place? 🤔
What is the material of the CVT belt? Rubber? Metal?
Man, how do you remember all that information? My head was spinning. LOL.
Hoping the CVT in my 2020 Accord holds up.
I do some research but learn as I go.
I also have a cheat sheet with a cross section view
@@speedkar99 Well, you never skipped a beat. Well done and helped me understand CVTs a little bit better.
I’m surprisingly watching all the videos on this channel😂 I don’t even know why.
Well thank you then 😊
very satisfying bolt removal
Glad you like it. It takes patience to edit.
can you do the "Subaru Performance Transmission" line of CVT thanks
I have a conventional Subaru transmission in gonna be taking apart soon for the AWD system.
The CVT would be awesome!
Has Nissan improved CVT reliability recently compared to previous years?
Would driving at 100 or 140 km/h for a long distance damage a cvt transmission?
No
Thanks man!
No problem!
Crezy (over) engineering. How much in labour costs to change one of the hydraulic pump solenoids?
Why? Just change the car!
Hey man I got a Rotax 717 Jetski engine that was seazed. It could be a cool teardown video. If you like you just pay for the shipping, I was going to send it to get scrapped either way and I thought you can do a teardown video instead.
How does the belt grip the variator ?
Pressure!
My car have almost 104 thousands mile on it, do you recommend I change the cvt fluid? Or just leave it, it is 2020 spark
Yes change it
just to be sure, some people told if change it, the transmission will be damaged.
Nothing will happen if I change it?
@@speedkar99 thank you for your time and advise
The Williams Formula 1 team built a F1 car with a CVT back in the late 80's/early 90's (I think), it was instabanned by the FIA.
Why? It can run 600 kph ?
@@playstation2bigs Because the gearbox can vary its ratio infinitely it can keep the engine at peak power, so it delivers all 800bhp all the time, and because it never changes gear in the conventional sense, the power is not cut between gearchanges. Search 'williams f1 cvt' as there are some videos on it with more detail.
I would like to know the theoretical benefit of a CVT transmission? Did the engineers think this through? Did they test it for reliability & longevity? It seems like a lot of components for very little benefit over a regular automatic transmission.
The benefits are the infinite gear ratios allows for better fuel efficiency, and they are generally smaller and less complicated to manufacture than regular automatic transmissions. And not all CVTs are created equal. These Jatco transmissions are historically less reliable than say a Toyota or Honda built one.
Yes, CVTs have been around for two decades and tested well enough. They provide efficiency over an automatic. Weither or not it provides financial benefit is another question.
Smaller, less weight. small cars. Longevity no
We've had plenty of 3rd gen prius's make it 400-500k miles or more for our courier fleet.. almost all the Ford transits's auto transmissions were toast before 150k miles..
I've heard nissan's have bad CVT's?, and are any subaru's reliable anymore? I guess its just like it always was, you gotta stay away from certain years/brands
@@rogerwilco1777 Prius is irrelevant to this discussion, because Toyota Hybrid transmissions are planetary gear + 2 electric motor "e" CVTs. They have absolutely nothing to do with 2-pulley CVTs like the one shown in this video.
I have a Subaru with a CVT, and it has noticeable “gear shifts.” What’s up with that? It does the normal CVT thing where it keeps the engine within a certain power range, but it also seems to shift gears and the higher trim levels have paddles that let you choose 7 different speeds. An explanation of that would be awesome.
I've heard someone added that because people weren't comfy with the missing shifts, so they added jolts via software. But also as he said, this one had a hi/lo range shift.
Most modern CVTs have simulated gearshifts for a more traditional feel. It’s basically a software thing if I’m not mistaken.
Although Toyota’s “Direct Shift CVT” for 2.0 engine in Corolla and Corolla Cross there’s a physical first gear for better acceleration at launch and then it shifts into CVT.
Anyone else here actually like CVTs despite their inherent faults? After living with four speed automatics a CVT feels like the future.
I got it in my crv and i love it. Unparalleled smooth acceleration. It does kinda make me nervous but ill change oil on early schedule and see what happens at least its a honda. And it does fake shift a little bit but only if you have a sloppy right foot
@@EpicDrew15 i have a renault koleos, same engine and cvt as xtrail, probably same cvt as rogue (jf011). i love it for that car and the use of that car. just family stuff, travelling anywhere without drama, etc. wouldn't want anything like this in a sportscar or hardcore offroader, but for a comfy family suv its perfect.
A CVT is to automotive experiences as a fleshlight is to relationship experiences. It begins and ends with utility and no joy.
@@POVwithRC yeah well, I traveled all around south america, nearly half of it on gravel, driving on isolate virgin beaches, even climbing vulcanos and such, on my cvt Renault. I wouldnt say it was no joy. Also, i wouldnt have done it with such pleasure in any other of my MT cars. Not while showing places to my daughter, talking to my wife, eating, driving... For a pure driving experience on such locations, i prefer a bike.
@@POVwithRCspeak for yourself because I prefer them. Let people enjoy things.
Now that I've taken it apart I'm gonna go ahead and put it back together
I chose to go with the desk ornament on that one
The oil control valve on a cvt oil pump does go bad causus the variator to and belt to slip.
Good to know
Was the car that you got the cvt from totaled?
read the desc. it probably was.
Yeah. It was rear ended and I bought the front.
I am actively looking for a city runabout with manual gearbox or even a torque converter auto. Where I live, I can't find anything. The only small ish car I found is an Indian made Suzuki Ciaz which I don't like and is too expensive for what it does
Stick with the manual transmission if you want longevity
was the car totalled ? Since it has 2000 km.
Yeah it was smashed in the back so I bought the front
CVT's are really great for MPG, just with any tranny change fluid more then recommended. Every 30-40k IMO with approved fluid. How about a replaceable belt?...they would never do that...These are non repairable, like the rest of the POS car.
Agreed. They are one time units built to a function.
Do all CVT cars come with a torque converter?
Yes. eCVT's on the other rhand have just a flywheel.
@@speedkar99 Wrong. Honda Civic CVTs don't have a torque converter. They have a start clutch.
OMG, seeing how you use grinder to open that machine, i definitely sure this machine belongs to your brother, he doesnt need it anymore cause he is married 😂😂. Awesome video and knowledge tough
Hahaha
this gearbox has more moving parts than a perpetual calendar mechanical watch :D
I feel like an automatic transmission is more complex. See my Jeep 8 speed video
ha aha ahah ahah hah aha. Busted both nuts on that one!
@12:24 I was thinking I'd seen this video before but i noticed it was new. I was confused af.
🤫
looks like there is a lot of potential failure points in that transmission .. designed by the sales team I would guess
The ultimate money gobblers
Yes there is.
Automatics, while generally more reliable, have more wear points
What is the area of the failure?
What failure?
The same gearbox is in Mitsubishi Mirage (Space Star in EU, 850 kg car), but it has the electric oil pump for Start/Stop to prevent low oil pressure. The same gearbox is in much heavier Nissan Leaf and others. This model has nothing in common with older models. Good video, thank you!
If GM uses the CVTs made by their Korean subsidiary - how can this be also be in the Nissan Leaf (which is a single reduction gear that never changes ratios)
There is no CVT in an electric car, i.e. Nissan Leaf.
My bad, Juke.
@@mantatrip9319 Then I agree 🙂
Good to know. Jatco makes CVT'S for more than just Nissan.
Good day from Waterloo. So u got your bro. dress shirt & pants , poor fellow won't have much left.
My riding tractor has cvt only with belt. Boy clean oil is important
Now it is his jeans boy o boy. LOL Thanks very good video.
You are welcome!
Yep I got my brother again, too bad