Continuously Variable Transmission
 

Am I the only one interested in the future of this technology from a performance perspective?
Didn't they get banned from F1 cars for giving rich teams an unfair advantage over poor teams?

I could be the only one, but remaining in the optimal rev-range throughout all speeds seems incredibly nifty to me.

I understand that they have their problems, and I don't think they're ready for a true performance rig, but I'm quite interested in the future of this sort of tranny.
:popcorn:

Yes and yes.

Quite ambiguous, thank you.

CVTs are the future for any engine that has a power curve.

I specifically said power curve because depending on the motor type (electric or internal combustion) if the power to motor speed graph is practically flat, there is no need for a transmission really. Put that power directly on the wheel! This harkens back to the four engines on four wheels concept they had. Transmissions are the single biggest loss of power before making any productive work so why not eliminate the tranny?

i'll gladly take my ancient-style dry plate clutch and synchronized manual transmission. with a clutch pedal.

CVTs are cool for some stuff, but i don't want ANY part of one in a sports car. :)

-Mike

I was wondering who would be the first.
I take it you prefer carbureted engines too, eh?
:iono:

If you're unclear as to my message, I'll just say "Thank you for providing no actual argument or real input and acting like a jackass who feels it necessary to cling to old technology just because you're used to it."

I can agree with the bit about each wheel having an engine thing, but how does that remove the power curve?
(I ask merely for information. Not just trying to contest your point.)

You are most welcome :thumbup:

When I get some time of from work I will elaborate more on this. I'll explain my answer and add more info as well.

I agree with you here.
Technology is a great thing. Can you imagine what it will be like when they have a cam-less motor running on solenoids. Infinitely variable lift and duration? Yes please.

Only problem I see with that is imperfect gadgetry. Small gadgets tend to fail, and the more gadgets you have within an engine and the more often they move, the higher chance of failure you have.
Part of the reason I like the idea of Wankel engines, in fact. Fewer moving parts.
:popcorn:

Edit:Also, that kind of thing relies on sensors, rather than a cam, obviously... this brings benefits, but also reliability problems and problems diagnosing problems when problems arise.

there is less driver skill required when driving a CVT or any other form of auto than with a proper manual transmission. less overall control.

i love plenty of technology, but i also still want some amount of skill required to be able to pilot a sports car quickly around a road course. :) CVTs take some of that away.

also, on a personal note, i quite dislike the feel of CVTs. believe me, i know they're really neat and have substantial benefits over normal automatics. i'm not a technology hater! i just happen to be a little bit of a snob/purist sometimes, haha.

-Mike

I cant really think of a sensor they would have to add. CKP and TPS would be the two major ones (already in use) just need a the software programed for the correct valve movement at any given throttle position and crank angle. It would be like all-time V-TEC but not gay. And yes im sure there is a LOT more needed for a cam-less motor to work.

I do agree with you though.

Ya failure is likely with the first few gens of a motor like this, but you can say the same thing about the CVT performance tranny. Everything breaks eventually. Like that wankel at 40,000 miles ;)

Meh. I'm interested in the overall performance of the machine. There will always be someone who's better at using it than everyone else.

Which is why I said "the idea of" a wankel. Theoretically, very reliable engines.. unfortunately, the application does not always live up to theory.
:cry:

wankels are quite reliable, until they are modified :(

Didn't mean to come across as "eliminating the power curve" but eliminating or at least minimizing the tranny. Even electrical motors with instant torque at 0rpm is not really accurate. Technically, it 95-99% torque at very low RPM. There is no such thing as instant in real life.

The best is when I have make an electrician understand that.

Ah. Fair enough, but does it continue at high revs? If it has a small range, it doesn't really matter where that range lies, if I'm getting this right. It'd still need a tranny.
If the torque continues up to high revs, then I guess you could just put a ratio usually seen on 6th gear on it, and it'd pull as hard as it can the whole way up, right?

Well the perfect powerplant would be instant 100% power and constant throughout a large range in speed. This way a transmission is not needed and cuts down the inefficiencies. Yes, it could multiply using a ratio via a tranny but if you had the perfect engine why bother sapping out the power of it using a tranny?

Then again, I'm no car engineer... I just love driving them.

The perfect tranny wouldn't sap power.

Ah but if you had no tranny, you have no sap!

Imagine a 18" wheel. It will take roughly 2315 revs per minute to achieve a wheel speed of equivalent of 200km/hr (200km/hr = 200,000m/hr = 138,889 revs/hr = 2315 RPM).

Now imagine if that wheel were directly coupled to say something like an electric motor? Now imagine if that motor were say the size of the wheel itself? At that point, sure a tranny might be able to multiply the output but would the weight justify it?

This is where my knowledge ends. I wish there was an automobile engineer who could chime in.

18" wheel has a circumference of 18*pi inches = 56.55 inches or 4.7 feet.
One mile is 5280 feet.
An 18" wheel (assuming that includes the tire, as I have been) would need to rotate at 1120 rpms to go 60 mph. (About 100 km/hr right?)
This is well within the range of electric motors, so we move on to power.
The electric engine in a prius generates 44 HP, IIRC. Two, assuming enough power to run both, would output 88 HP.
Tesla's 375 volt motor makes 288 HP and 273 lb/ft of torque. Makes constant torque up to 5000 RPMs and its power peaks where the torque starts to drop off. With 1:1 ratio, 5000 RPMs = 268 mph on an 18" wheel.
I don't know the size of either of these motors, but I'd guess the Prius motor is closer to the size of the wheel. Personally, I'd just put the Tesla motor in the center between both rear wheels, maybe a straight 2:1 gear ratio (Which would put 4480 (engine) RPMs at 120 MPH), or something connected to a drive shaft, connected to the wheel.
Even 88 hp though, combined with the low CoG from having batteries in the floorboards, it probably wouldn't be hard to make it lighter than a conventional car, but don't quote me on that.

Whats wrong with Carbureted engines?

Early Mazda wankels had their share of problems, but much of the Apex issue can be resolved using FD seals.

On a sidenote, the dark myth behind wankels being impossible to work on is completely bullshit. It is by far the simplest engine I've ever had the pleasure of helping tear apart and rebuild. I mean its REALLY simple. So even if it does go out, you can (with some practice), remove, tear down, and rebuild a wankel within a day. Getting everything setup properly again can be a hassle, the but the actual tear down and rebuild? Stupid easy.

What's wrong with horse-drawn carts?
Srsly. We should have stopped developing new technologies ages ago.

Cleaning up the poop and maintenance.

But you missed the point. There's nothing wrong with liking Carbureted engines. Yes, FI brings more pro's, but mechanically there's nothing wrong with driving a Carb'd car. If anything, its simplicity is its greatest asset.

Would I carb the AE86? Nah. Would I swap an EFI engine into a 240zx? Hell no.

Someone's gotta clean up the junk and maintain every vehicle ever made. Just because you don't see it doesn't mean your car makes no waste.

... but that's beside the point. I didn't say there was anything wrong with liking carb'd engines. I was just saying, if you were designing a motor today (assuming you had the knowledge required already), you probably wouldn't put a carb on it.
:iono:

Well I'd rather change oil than clean up horse shit. Smells better.

Though I'd probably rather clean up horse shit than change diff / tranny oil. Horse shit smells better.:bellyroll:

Fair enough. I have to change the ATF in my civic soon. Not looking forward to it.
:thumbdown:

Ah, but you can't fertilize your veggie garden with used oil!

back on topic- Transmission oil is pretty rank. I'm not looking forward to changing the tranny oil in my Celica. Not because it's rank, but because I practically have to contort my body in order to accomplish the task.

Well... you could.
I'm just saying... it's an option.
:iono:

I've had the chance to compare a CVT head-to-head with a 6-speed automatic. It's a perfectly economical choice for people who consider driving to be a chore. If you don't care how it feels, that's fine for you, and more economical.

I like to compare it to going from 0 - 100 MPH on a runway in an airplane, or going going from 0 - 100 MPH on a runway in an automatic BRZ. The airplane doesn't shift and just provides steady acceleration, while the BRZ shifts through the gears from 1st to 6th. The BRZ is much more exciting, while the airplane is much more comfortable and even relaxing.

A direct-drive electric motor is even more efficient than a CVT, since there are no power-train losses. Why not go electric?

This is from 2010. He hasn't been on this forum since 2011. I don't think he cares. How did you even find this thread?

Yes

Heheh, tranny. Do a google image search with that term and you will get something with more balls than a CVT.

There is a place for these, but not in any sort of performance car. Some grocery getter, sure, why not? It's low stress and nobody is in a hurry, perfect situation for a scooter drivetrain.

http://www.scootercommunity.com.au/b...%20scooter.jpg

You described an electric car. Yes please!

[ame="https://www.youtube.com/watch?v=uXq9j8M-KpU"]Electric car vs bike: Citroen Survolt vs Agni Z2 - YouTube[/ame]

I'm sure the OP is a fan of the rotary, I mean, it's new and all things new must be better, right? :bonk:

https://theweedfeed.files.wordpress....h-paradise.jpg

Exactly.

No idea how this thread got resurrected but I am having a blast watching Themad ragging on guys that haven't been here for 4 years.

in a nutshell this is the new koenigsegg regera

VALIDATE MY RAGE, DAMMIT! :mad0260:

http://1.bp.blogspot.com/-42WHv_-X5Q...age%2BQuit.gif

He is owning them so hard...they won't even respond.

It'll be a cold day in Hell before I own a car equipped with a sh*tty CVT