"Raphmoe" (raphmoe)
11/12/2014 at 08:23 • Filed to: raphmoe, transmissions, save the manuals, manuals, cvt, toyota, beige
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"Raphmoe" (raphmoe)
11/12/2014 at 08:23 • Filed to: raphmoe, transmissions, save the manuals, manuals, cvt, toyota, beige | 4
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Good evening and welcome to Raphmoe analysis, where your humble journalist looks at a topic of car culture and writes about it like you've never heard about it before.
I have driven many miles in a Prius (my parents own the car), and am convinced that no other transmission would work as well with the hybrid drivetrain. It's designed to work together harmoniously for efficiency and acceptable performance, and the damned thing stubbornly returned 45 mpg in mixed driving no matter how hard I thrashed it and redlined it.
There are precedents for performance vehicles with CVTs that are very thrilling (snowmobiles, anyone?), but because we're accustomed to a sharply-escalating engine sound indicating performance in cars, I don't think we're ready to accept them.
But consider this: most drag racers are automatics, right? With ultra-high stall, non-locking torque convertors, they act and sound pretty much like a CVT. And they're designed for maximum acceleration, right? No reason we can't adapt that line of thinking to performance cars that are made to handle a road course or a twisting country highway, too. It's just going to require a shift in perception about what a performance car should sound like and how much control we should have over the gear ratios.
Now, some of you may be asking me at this point: Raphmoe we want a manual! Well, Manual CVT transmissions would work, and here's how:
I can imagine a set of programmable ratios activated by paddles, which only change upon command, then add a standard, pedal-activated clutch before or after the CVT pulleys.
Hell, you could even take it one step further and introduce a video game-style stick shift, in which the gates are switches that activate the chosen ratios. And you could have different sets of programmable ratios, for surface streets versus highway (or just have 8 ratios, then skip a few when you don't want or need them, though it gets easier to get lost in the shift gates with so many ratios, I'm sure).
Another notch? Have a full auto mode that can be activated when the car is being driven by a valet or if your significant other is a non-enthusiast that doesn't care for self-selection of ratios.
Sound off in kinja below on what you think.
BJ
> Raphmoe
11/12/2014 at 08:31 |
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I can imagine a set of programmable ratios activated by paddles, which only change upon command, then add a standard, pedal-activated clutch before or after the CVT pulleys.
!!! UNKNOWN CONTENT TYPE !!!
Another notch? Have a full auto mode that can be activated when the car is being driven by a valet or if your significant other is a non-enthusiast that doesn't care for self-selection of ratios.
I think you've just described a paddle-shifted sequential automatic transmission. I hate to have to break it to you, but not only is this no longer a CVT, but it's also been done before...
Cé hé sin
> Raphmoe
11/12/2014 at 08:32 |
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It could be done but you'd end up with an inefficient transmission with mushy "gear" changes. There's a reason why nobody has recently tried this.
Mind you there have been CVTs with manual clutches in the past - some motorcycles had them.
MasterMario - Keeper of the V8s
> Raphmoe
11/12/2014 at 08:38 |
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if they made a CVT work to the full advantage of a CVT I think more enthusiasts would be on board. just think...you stomp on the throttle the engine goes to its peak power rpm and just stays there, then the CVT continually changes the speed of the car for you. the fact that CVTs are kind of in between a normal transmission and a true CVT right now (false "gears" and limited ratio continuity) I think are their main down fall right now
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Raphmoe
> BJ
11/12/2014 at 08:38 |
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Hard to say for sure.
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Cé hé sin
> Raphmoe
11/12/2014 at 08:39 |
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"...then add a standard, pedal-activated clutch before or after the CVT pulleys."
Before. Always before, you want to avoid the extra torque of bottom "gear".
roflcopter
> Raphmoe
11/12/2014 at 09:08 |
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I actually had a similar-ish idea for F1 a while ago...
You put CVTs in the cars, you leave the paddles, make them pressure sensitive(like Xbox triggers) and let them control the gear ratio up or down. Now you can increase engine braking into a turn, jump right back to your powerband and go. This would actually be a lot more challenging for drivers than it is currently and would make the cars faster and make the work for engine builders easier(which they desperately need right now).
Sweet Trav
> Raphmoe
11/12/2014 at 09:10 |
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Raphmoe,
I work closely with CVT transmissions and their design at work. one of the key elements is the torque handling capabilities of the main band, or the temperature of an extroid CVT transmission oil. Add to the fact that the bearings which the primary and secondary drum are loaded in different and varying ways, exposed to crazy amounts of heat they aren't currently a realistic high performance solution.
for lightweight low torque cars, yes they could be lots of fun, however, for our big honking V8 monsters... nope.
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Sweet Trav
> Raphmoe
11/12/2014 at 09:15 |
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Also, some good reading on CVT Transmissions.
http://www.nissan-global.com/PDF/tcvt_e.pdf
Shift24
> Raphmoe
11/12/2014 at 09:20 |
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Another reason they have not taken off is they don't have the reliability of the standard torque converter automatic. Now I would understand if they were cheaper and easier to fix but they're not. Also not many shops dont know how to work on a CVT so most just don't. Also parts are hard to get for some, GM used CVTs in the mid 2000's on cars and then quickly abandoned them after reliability problems so parts and transmissions are hard to come by. Granted it is a better technology and in theory should replace the normal slush box but its newer with small support right now.
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BJ
> Raphmoe
11/12/2014 at 09:38 |
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Oh snap, I just realised that that was intentional...
—-> JOKE
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——> MY HEAD
Jonathan Harper
> Raphmoe
11/12/2014 at 11:56 |
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Sound off.
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Raphmoe
> Jonathan Harper
11/12/2014 at 15:26 |
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Huh?
I am quoting my favorite writer on Jalopnik, Mr. Orlove, "sound off in kinja" is a great way to generate discussion on interesting articles on car culture. Here are a few examples:
http://jalopnik.com/5971345/watch-…
http://jalopnik.com/5950722/a-stun…
http://jalopnik.com/what-the-hell-…
etc.
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Jonathan Harper
> Raphmoe
11/12/2014 at 15:29 |
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And I subsequently sounded off with a sound off.
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Raphmoe
> Jonathan Harper
11/12/2014 at 15:33 |
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Sound on.
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Jonathan Harper
> Raphmoe
11/12/2014 at 15:34 |
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Raphmoe
> Jonathan Harper
11/12/2014 at 15:35 |
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Captain of the Enterprise
> Raphmoe
11/12/2014 at 15:36 |
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For a performance application CVT are good for acceleration but are harder to throttle steer because you can't downshift going into a corner so you would have to trail brake to keep the cvt in the ratio you wan't
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Jonathan Harper
> Raphmoe
11/12/2014 at 15:39 |
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Captain of the Enterprise
> Raphmoe
11/12/2014 at 15:55 |
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Also HNNNNNNNNNNNNNNNNNNGGGGGGG
HONDAD
> Raphmoe
11/13/2014 at 09:44 |
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Am I mistaken in thinking the Honda CRZ was the first car with both a CVT and a manual transmission? And I've always been confused by this setup, because isn't the shifting just basically faking it? Kind of like how newer cars with CVTs pretend to be automatics and act like they're shifting even though it's unnecessary.
{Edit} I was mistaken. It was the first hybrid with a manual.
blackjack666
> MasterMario - Keeper of the V8s
11/17/2014 at 03:41 |
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Maybe I can't read, but isn't this what a CVT already does at full throttle? Except Audis's Multritonic in Sportmode.
I have long driven a Mercedes CDI with the Autotronic transmission for commuting and really preferred it thanks to the low revs and the engine kept just at it's peak of torque. Barely came over 2000rpm with normal driving. On the Autobahn though, the transmission rather likes to rev a lot instead of using the torque though I think this is more of a software problem.
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MasterMario - Keeper of the V8s
> blackjack666
11/17/2014 at 08:32 |
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I have only driven a couple CVT vehicles, but from my experience and from what I've heard CVTs are rather limited in being used to their full potential. They aren't strong enough or reliable enough for high horsepower engines and that the those limitations have led to a current generation of CVTs that aren't able to be used to their full potential. They are well suited to general daily driving in their current state, but as far as I understand they aren't developed enough to the point to be used in motorsports or even sporty cars yet.
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blackjack666
> MasterMario - Keeper of the V8s
11/17/2014 at 14:13 |
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Yeah, I've also heard that especially torque is a huge problem