CVT Disadvantages
lol, the disadvantages that wikipedia has listed are quite humorous as they pretty much are advantages in reality. That and it describes the Typical American thought process when it comes to the way things should work.
Advantages
Disadvantages
|
I didn't know the jerk during a shift was because the car was using so much power! Thank goodness I learned this *rollseyes*
|
lol, when I accelerate in a normal Auto car, you don't feel the shifts cause of how little I'm using the gas. That and I keep my Jeep running good :thumbup:
I didn't know that having a smooth running car was an advantage! wait.. its also a disadvantage??? WTF!? *brain explodes* |
Quote:
Seriously, what's wrong with a double edge sword? I'd have more of a problem with the hilt-less sword :p |
So... CVTs are used in heavy equipment!?!?!? I thought they were not in high production because they couldn't handle torque?! Why aren't all the EV people jumping all over this tech? Why aren't all the elctric motor companies offering computer controlled CVTs matched to their motors????? I love driving standard, but hell, a CVT would be sweet...
I would love to see a car with a "manual cvt" ... instead of a gear shift, a smooth lever :) |
Quote:
|
Bleh, that's gross... i want a smooth lever that allows me to control the CVT ratio infinitely. Why on earth would anybody who knows anything about driving a sports car WANT to force the tranny to a ratio where the revs drop out of the prime zone?
|
I hate 'em
My wife has an altima V-6 with CVT. Just getting off of the gas pedal is akin to applying the brake. It has no coast in gear kind of affect. I also believe that if I were shifting a manual, I'd almost always be in a higher gear than it chooses for me. Both of these cost me at the pump.:(
|
That is entirely caused by bad software. Do you know if the gas pedal is cabled to the throttle plate? I would think that a truely perfect CVT system would use a computer controlled ratio AND throttle plate, making the pedal only a "speed setting" pedal... keep your foot where it is and the control system should align its throttle position and RPM on the best BSFC location for cruising.
|
the biggest problem CVT's have with people operating them is actually the "motorboating" effect. you press the pedal and the engine speeds up but you dont, untill it gets the ratio's and friction setup right. there are many out there now that dont do this. my sister loved hers in her saturn ion
|
So in effect, ALL of the dissadvantages are in user PERCEPTION? And the advantage is that it makes the car more powerful and fuel efficient? Well we got used to replacing horses with engines, i think we can get used to the motorboat effect and coasting with your foot on the gas.
|
My mom's caliber has CVT with "Autostick"
Basically, its a clutchless manual sort of thing. when your shifting manually, you can control what gear you want it to be in. The quietness is a factor when using the autostick option because you have to look at your Tachometer cause the car is so dang quiet. But I love it. when you accelerate, it goes to just under 2000 RPM and stays there, and when you get to 55, it is still there. and its so smooth. *drools* I can't wait till I get it, I'll be 2 years into college, but It'll still be better than driving my Jeep around thats for sure. I can pull the max out MPG's on my jeep by driving like an idiot. I don't know how people complain about getting like 23 mpg in it. How do they do it??? I got 30.6 driving 75 from here to Kansas city and when I got there thats when we filled up. Also, when your listening to music, the details from your music really sing.. mmmm |
What is Autostick and how does it relate to CVT?
|
Its a feature that the Caliber R/T's CVT2 transmission has that allows you to shift like its a manual, but on an automatic transmission. It creates simulated Gear ratios that allow you to control the ratio of the CVT's belt/pully's whatever type of CVT it is so that you can have more control in situations like snow, acceleration, and want an overall Manual transmission experience without the actual manual transmission. Makes it good if you like driving stick but your wife has no idea how to drive stick. You can also keep it in a high gear ratio around town to lower RPM's.
When using the Autostick feature in the Caliber, 1/4 mile times are faster and you don't have to wait for the computer to decide what position the V belts need to be at in order for the best gear ratio, you decide that, and launches are faster. Autostick is only available on the higher end models, mostly for performance applications. But you can also use it in town or while coasting downhill for better coasting and lower RPM's for better fuel economy. You gotta know how to drive it though. |
I wish i had funding dollars because i could totally develope a control algorith that would be way more advanced that anything that you all are telling me that production cars do.
It is absolutely SILLY that this autostick mode would have a faster quarter mile than CVT mode. CVT mode should simply lock the engine RPM at max power and change the gear ratio to suit wheel speed. It should not be beatable in acceleration OR mpg. |
Quote:
|
yea, the main reason is price. otherwise, it will either not sell or no one will buy it. they kept it simple and went with nissan's already developed technology.
|
All i'm proposing is a better control system for the CVT, no mechanical changes... except that i would want the gas pedal to be an elctronic input and have actuators at both the throttle plate and the cvt gear so both engine and tranny are in my control.
I think the only hurdle is that people are dumb... which really blocks most of the world's progres... it would just feel "different" and that my drive off the idiots. It would always cruise at the throttle/rpm that would produce the required HP to maintain speed while being at the most efficient available point on the BSFC chart, and at pedal positions above neutral it would seek points on the chart with scaling hp, so at full throttle it would seek its way to the greatest hp output. Hard to describe in 500 words or less, but I understand myself so it must be possible :) |
I agree with Matt 100%! CVTs are great, in concept, but all the stupid people of the world that think they need to jackrabbit everywhere have made the execution way off target for efficiency. They're capable of being lighter, smaller, more efficient, more quiet, and have a wider total spread of ratios compared to a geared transmission regardless of all the available ratios in between min and max. The ONLY disadvantage I see them having is the slightly limited torque handling which could make low speed, high ratio driving difficult/a little less efficient/damage the trans, but I'm talking <20mph, top gear/ratio/whatever. I can also kind of understand the weird sensation of watching the speedometer rise and not the tach, but I would think the hoards of drones that have been driving mushy automatics forever would be used to this. I, being a 12 year veteran of the 5 speed, automatically think "Great, there goes my clutch!" This is just something that will seem more natural with time for me and the rest of society. I don't understand why the programming on the CVTs is fixed. Sports cars have buttons for their automatics that allow them to shift quicker. I don't even need manual slide ratio control like Matt wants even thought that would be sweet! All I need is a button (like sport shift or 4wd) or a selector (like the knob that chooses defrost or floor, does any vehicle use those anymore) that would let me choose "granny" mode or "lead-footed idiot" mode and maybe even another option in between. That's what it would take to get me out of my manual.
Anything that's programmed for the status quo and unchangeable is not for me, because I am not the status quo and I don't think anyone else here is either. If someone here is satisfied with the status quo why are they on a modding website of any kind? |
Quote:
New CVT's use advanced lubricants that allow them to do this. Tractors now Use CVT. Old CVT's before 2005 had the low torque problem, but that has now been fixed. |
Quote:
|
...technically isn't a sports car with paddle shifters technically an automatic?
|
Quote:
or do you want to call the 4 wheel drive, selectable automatic, rear engine ungodly fast cars they produce "non-sports cars"? I remember hearing that "sports car" was defined by a manual transmission, front engine rear drive 2 door car. which would make the top sporty cars, not sports cars, but the miata fits... seems a little backwards. or wait, well, they DID come up with another term..... "super car" which I belive the ferraris and porcshes and the lambo's fit into (well the lamb is more of a hypercar - all show with a big engine but not "fast" like a supercar) |
Quote:
|
Quote:
|
DPV - can you coast engine-off with the Caliber's CVT? What does the user manual say about towing?
|
... I'd have to check that out actually. I'll make a note of that in the back of my noggin...
I know that when you have your foot off the gas fuel cutoff is pretty much instant and it doesn't seem to kick back on until around 15 or so mph. once in MO i was going down a steep grade using no gas for about 2 miles and it kept around 65-70mph, but the thing slows down so much when you take off the gas pedal you never really have to use your brakes if you slow down early like I do (save money 2 ways! woo) |
Quote:
|
CVT tranny's are lighter and smaller than their automatic counterparts.
And the Caliber uses these type of lubricants, so its not just earthmoving equipment that uses the "new" lubricants. |
Quote:
Usefully, when changing virtual gears, the change was slurred. This allowed the revs to stay within about 2-300rpm when going through the gears. Aside from the awful 5 second pre-programmed start routine, the gearbox was the best I've ever driven. Here's a clip of the car in action: Focus CVT in action Cheers, Andy |
Quote:
|
All times are GMT -4. The time now is 04:24 PM. |
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com