I don't know about "good" or "bad", but they tend to be less responsive and create more of a spongy, floaty feel. In terms of creating a more connected driving experience, the best would be either manual or dual clutch systems. Obviously you can create good or bad transmissions in all of these categories and you may prefer a softer ride - there are customers who pay a lot of money for a softer ride or even be driven along, it just depends on what you want.
> but in regular drive, the lack of hard shift is really pleasant.
I sometimes drive an US-designed car with, I assume, an US-designed automatic transmission (traditional planetary sets + torque converter) and I was actually surprised it doesn't shift very smoothly, worse than a good driver on a manual and much worse than dual-clutch transmissions. With the latter it's pretty much impossible to tell when it is shifting if you cannot hear the motor rev.
(When you switch that car to 4L... oh dear, every shift feels like a learner driver learning to shift with the entire car jerking around. Everyone nods in approval!)
> I sometimes drive an US-designed car with, I assume, an US-designed automatic transmission
regular Automatic transmissions (not CVT) have been commoditized and are usually subcontracted out to dedicated vendors that make transmissions and sell them to auto manufacturers all around the world, so the nationality of the car vendor isn't going to tell much about transmission quality.
For example, the largest market share of car automatic transmissions belongs to (Japan based) Aisin, which sells transmissions to Ford, Toyota, BMW, Skoda, Chevrolet, Suzuki, Volvo, Hyundai, and many others.
https://en.wikipedia.org/wiki/List_of_Aisin_transmissions
A lot of the bus and truck transmissions are made by (US-based) Allison and they are sold all over the world and have the largest share in duty engines.
https://en.wikipedia.org/wiki/Allison_Transmission
There is large variability in perceived transmission quality, depending on everything from how the software controls it to form factor (real wheel or front wheel) to issues of reliability and build quality, but there are excellent US transmission vendors as well.
Even in the world of PEV there is a trade off between fuel economy and performance, so this has nothing to do with transmissions.
The fact that you use energy stored as electricity does not get around the laws of inertia or air resistance -- accelerating a mass quickly will always require more energy than accelerating it slowly. And in the PEV world, since re-charging can take an hour instead of a minute, the consequences of draining the battery more quickly are going to be more of an annoyance.
Transmissions come up in that this is how some automakers meet efficiency requirements -- by taking away some control over acceleration from the driver by using a transmission that is programmed to shift gears in the higher rev ranges, with no manual override. But this makes the car less responsive.
Here, Tesla's brilliance shines, not because it doesn't have a transmission -- they can and do put in software that limits acceleration, so they could have done the same thing to improve range, but onlike others that improve efficiency by making the car less responsive to the driver, they improve efficiency by having a more efficent engine or a lighter car, while keepig the car very responsive to the driver. The real brilliance of Tesla is in building cars that are fun to drive (read, responsive), and indeed most of the innovation of electric cars that has been successful in the market was based around improving acceleration and adding more torque, making the car more fun to drive. That's why models like the Tesla or the old Ferrarris with electric assist are much loved by drivers, even though models like the Leaf and Bolt are not. Drivers care about good handling.
> Even in the world of PEV there is a trade off between fuel economy and performance, so this has nothing to do with transmissions.
CVTs are not efficient because they control the rate of acceleration. You can over-rev a CVT and get as much acceleration as your engine (and it's transmissions losses) will allow. CVTs are efficient because they allow the engine of the car to operate in its most efficient power range more of the time.
EVs run into this same issue, but the way Tesla anyhow solved for it is pretty wild. Dual motor Teslas have 2 different motor/ drivetrain gear ratios. The rear wheels are most efficient at lower speeds and when you are driving slower, they get most of the power. The front wheels are most efficient at higher speeds and when you are driving faster, they get the most power. This way the most efficient motor is always doing the most work at any time. This is likely why the AWD Teslas have so much more range than the single engine/ RWD models.
There is a good article talking about EV transmissions here, the bit about Tesla's 2 gear ratio setup is about 12 paragraphs in.
I can't speak for nowadays, but my experience with early non-hybrid CVT vehicles was negative. I test drove a Nissan Versa and the engine was sitting at around 4k RPM doing 60 MPH on the highway. It was very loud for a small hatchback, and generally unpleasant to drive.
I think I tested the Versa in 2008. I specifically raised this concern with the car salesman who was sitting in the passenger seat; he insisted it was normal. Weird!
I had a CVT car, and that never gave me any problems (over 180K kms).
My newer car has a traditional automatic - the only reason I didn't go for a CVT is simply that the model I have doesn't come with that option (otherwise I would have opted for it).
They're supposed to be more fuel-efficient, I guess? I've only driven one or two, but my perception is that they're slower to respond.
My minivan has a 9-speed automatic transmission and the engine spends 99% of its time either off, idling, or around 1.9k rpm, so it seems like it's efficient enough.
No. It's like when some some old farts try to tell you that 24fps is just great for movies. The reality is only that people are accustomed to the lower temporal quality of 24fps movies from childhood onward, and don't like the change to something better.
Unless you have some evidence proving me wrong, my feeling is that the people who don’t like them are very loud is saying so, while the rest of us simply focus on other things. Some manufacturers like Nissan just did a really bad job tuning their CVTs at the beginning, but I hear this has since been addressed. I never had a problem with the CVT in other vehicles.
Is that a good thing?