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The diversity in today's transmissions is finally bringing in a golden age... except for manual transmission fans (though still the most economical option, auto
by dragontamer 3y ago
The diversity in today's transmissions is finally bringing in a golden age... except for manual transmission fans (though still the most economical option, automatics have grossly improved with all of these new technologies).
* Hybrids are largely "Power Split Devices" (Toyota / Ford / etc. etc.) which use a planetary gearset to kinda-sorta make a CVT-like approach.
* CVTs with belts and/or cones are all available, to varying qualities.
* Dry DCTs have created sub-100ms shifts in automatic transmissions
* ZF8 (wet-clutch planetary gear / torque-converter traditional automatic) has sub 200ms shifts (~150ms or so for the typical ZF-8). Just old tech but done exceptionally well today.
- whalesalad 3y agoCVT's are 100% pure trash. Dig the ZF8 in my RAM a lot. Did not like the 10 speed in my F-150, ZF is much better.
- zubiaur 3y agoAgree on pure IC ones. Hybrid ones, like the one on the Prius, while still technically a CVT, are nothing like the jatco crap Nissan and others had been putting on IC cars. They are quite reliable.
- kQq9oHeAz6wLLS 3y agoThe later Nissan CVTs are apparently fine, although they were unable to overcome the damage done to their reputation.
- brendoelfrendo 3y agoThe "eCVT" in the Toyota hybrid system isn't a CVT at all, but rather a system that uses the electric motors with planetary gearsets to keep the engine operating as close to its optimal RPM as possible: https://youtu.be/O61WihMRdjM?si=hPoLm8EZnbiLH60h https://youtu.be/O61WihMRdjM?si=hPoLm8EZnbiLH60h
- hinkley 3y agoI think it was Honda who tried out a 2 motor planetary gear setup to eliminate the transmission and I don't know why it was abandoned because it was brilliant. The idea was that you need a certain velocity and torque to hold the drive train at a given speed, and instead of using reconfigurable gearsets for that, you use a differential, and one of the output shafts is sometimes an input shaft. One of the output shafts is attached to the wheels, the other to a motor. At some speeds output shaft B is stationary. To accelerate, you feed power into the motor and now it's speeding up shaft A. At lower speeds, you bleed power off of shaft B by running the motor as a dynamo, using it to charge the batteries and run auxiliary equipment. In the hybrid version there was an ICE on the input shaft (or an ICE and a ganged electric motor) but on a full electric you could run two motors with different torque curves and balance the inputs for each speed.
- organsnyder 3y agoMy Pacifica PHEV has that configuration. It works very well.
- kube-system 3y agoToyota is the manufacturer famous for their 2-motor planetary setup (they call it Hybrid Synergy Drive), and they've licensed it to a couple of other manufacturers, like Ford and Nissan. Honda's old system, 'IMA', which was a traditional ICE drivetrain with a motor assist. They abandoned it because mild hybrids don't really deliver a good value. It's a lot more cost for not very much improvement in economy. Honda's new system, E-drive, usually operates like an EV with a generator attached, but it also has a lock-up clutch to allow the engine to direct drive the wheels in cruising conditions.
- dragontamer 3y ago> 2-motor planetary setup (they call it Hybrid Synergy Drive) 3-motor actually. https://eahart.com/prius/psd/ https://eahart.com/prius/psd/ 2x Electric Motors + 1x ICE motor. Its a bit confusing but there's a lot of Youtube demos, webpage-demos, and simulations to help you understand how it all works.
- queuebert 3y agoThe 10R80 in the F-150 has known problems, while the ZF8 is one of the best transmissions currently made. It's also used in BMWs, the Toyota Supra, and the new Ineos Grenadier. Having driven it, my only issue was that it was slow to switch from deceleration/engine braking mode to acceleration mode. That programming allows it to feel more like a manual when you let off the gas, but it takes a good fraction of a second to switch between them.
- whalesalad 3y agoMy truck in tow/haul mode behaves very well with engine braking. Very responsive. I’m guessing it’s a software thing.
- mordechai9000 3y agoI love driving my manual, although I recognize in this day and age that is probably kind of silly on my part. Are the new automatic transmissions really as much an improvement in fuel efficiency as the manufacturers claim? I'd like to justify buying another manual, but I can't ignore a 4 mpg gain in fuel efficiency.
- harkinian 3y agoI think the reason automatic is more efficient is you'll often get more gears, maybe like 12, so it stays closer to the most efficient RPM. And it'll shift way up just cause you let off the gas for a second, so engine-braking is minimal. Stickshift drivers can maaybe do that, probably not. I can see those two things saving 4 MPG. Also have no idea if the EPA tests account for average stickshift driving habits. And all that is without considering hybrid tech.
- kube-system 3y agoI've had a couple of hybrids and I've always been able to hit the EPA numbers as long as I'm not driving in the mountains. And on state highways I can usually beat them. Some of the numbers hybrids are putting down are damn good these days. The base Camry hybrid starts under $30K and gets >50mpg.
- oangemangut 3y agoif you use fuel consumption instead fuel economy to look at it the differences can be small. I have both auto and manual transmission vehicles, and for me personally, I almost always beat the rated consumption numbers in manual and rarely beat it in the auto. This just boils down to how I drive; I end up going much slower when driving manual (in a small Ford Ranger pickup) than I do in either auto.
- carbine 3y agoI love driving my manual too and would like to beg you to keep buying them -- the few of us that still appreciate them are the only shred of remaining market
- bluGill 3y ago
- hinkley 3y agoI got my dual clutch in 2010 and have barely felt guilty about not driving stick since then. Particularly because in Volkswagen's rendition of DCT, the car will react to riding the brake by using engine braking. There are certain hill shapes where it doesn't really work, but it works nearly perfectly on shallow inclines. Light tap at the top and it will hold speed the entire way down. People will often point out that you can use the override but I feel like that misses the point. There's what a person can do, and what they will do, and when we are talking about something like global fuel economy and carbon emissions, 'will do' is the only metric that actually matters. And hybrid electrics and DCTs fare better in the 'will do' category.
- kube-system 3y agoI wish more people knew how the power-split devices in modern hybrids worked. The 'eCVT' and similar terminology they often get just doesn't do it justice. They're a beautiful design, and entirely different than 'CVTs' as most people know them. Some of these designs are mind-blowingly simple. My favorite is Honda's E-drive: https://www.youtube.com/watch?v=QLUIExAnNcE https://www.youtube.com/watch?v=QLUIExAnNcE
- deleted 3y ago[deleted]
- harkinian 3y agoMakes it hard to explain to people what my DuoSelect is.
- grujicd 3y agoSome of new hybrids remove transmission altogether - Honda and Nisan use ICE as a generator and wheels are powered by electrical motor. Honda hybrids also have a clutch to connect gas engine directly to the wheels on motorway speeds to improve efficiency. And it simulates sound of gear changes during acceleration even if there are no gears whatsoever, since that's apparently what makes it more exciting and enjoyable to us petrolheads: https://www.youtube.com/watch?v=1JbpJR4frGY https://www.youtube.com/watch?v=1JbpJR4frGY
- throw0101b 3y ago> Honda and Nisan use ICE as a generator and wheels are powered by electrical motor. In some ways I'm surprised that more EVs don't have this as an option: * https://en.wikipedia.org/wiki/Range_extender https://en.wikipedia.org/wiki/Range_extender
- andruby 3y agoIt’s a lot of extra weight to carry around and extra systems that can break and need maintenance. Especially tricky since they’re only expected to be used sparingly. Batteries keep going down in price and weight
- dragontamer 3y agoToyota's Power Split Device seems like a superior design to me. 1. Change the engine to Atkinson Engine. This makes low-end torque terrible. 2. Make up for low-end torque by paring a small 80 horsepower electric motor (which handles 0rpm exceptionally well). Atkinson Engine does 2000+ rpm / highway speeds exceptionally well. Use a computer + a 3rd electric motor to configure the planetary gears to make the EV motor #1 and ICE engine cooperate best. 3. Beef up the alternator into a proper generator (to charge the battery when its low). Use the motors to hold the car still if stopped at a stop-light but keep the ICE engine on the generator to build up the charge you need to take off later. 4. Use the EV motor as the starter (hook it up to the engine to start it up, much like a traditional starter). -------- As such: the Power Split Device removes the alternator, starter, and traditional transmission (with the EV motor#1 and EV motor#2 + computer allowing different configurations / rotations to recreate alternator / starter / transmission-like behaviors). With... here's the big magic... the ICE + EV Motor being able to assist each other on the highway. (Honda's ICE as Generator approach leads to 100% ICE on the highways). Toyota Prius has a better ability to mix EV vs ICE (even the ability to run 100% EV at the push of a button, though at dramatically worse performance since IIRC its only a sub-100hp electric motor).
- mullingitover 3y agoI used to love driving a manual transmission, but if you live in a city you have to be a masochist to use them. I drove a six speed on a 30-40 minute commute on the 101 in LA for just a few months and started developing knee pain from constantly using the clutch. I wish Honda made a Civic Type R with a DCT.
- bluGill 3y agoI found the clutch was easier once I started finding the average speed of traffic and did that instead of changing speed to keep up. Those large gaps were safer too.
- harkinian 3y agoPeople abuse the gaps in some places.
- lotsofpulp 3y agoAlso known as using available road capacity.
- sandworm101 3y agoI totally acknowledge that automatics are now technically superior in most ways. But I just cannot stand the robot between me and what I want the car to do. When I am stuck in a snowbank and want to rock the car, or am about to pass a tuck on a mountain highway, or want to engine brake down a long hill, I don't want an unpredictable machine trying to decide when and if to shift. I would buy an automatic that would never shift unless told so to do, but such things are not available on consumer cars. Automatics are also just one more unfixable thing to go wrong. An automatic has so many moving parts, most of which are tiny little things buried deep inside. Manuals just run forever, needing at most new clutch plates or slave cylinders, things external to the actual transmission. Fixing anything to do with an automatic is akin to automotive heart surgery.
- 15155 3y ago> I would buy an automatic that would never shift unless told so to do, but such things are not available on consumer cars. DCTs will absolutely give you this experience. Most don't expose a UI for shifting from directly to any gear arbitrarily, though.
- actionfromafar 3y agoVolvo had at least in 2015 automatics which would not shift unless told.
- hcarvalhoalves 3y agoVW/Audi DCT has manual mode that allows shift up/down and stays set on a gear. The only difference is it won’t comply if you aggressively downshift or will eventually shift up if you rev too much.
- sandworm101 3y ago>> The only difference is it won’t comply Ya, I don't want to get into an argument with my car. I want a transmission that will actively allow the engine to stall, or let the rev limiter do its thing. I also want a clutch that I control, one that will engage when I ask it rather than a second later, which is a bigger deal in snow/mud/rock. A couple weeks ago I had to rock my car out of some deep snow (snowed-in parking spot). An automatic just will not engage/disengage fast enough on command for such trickery.
- fragmede 3y agodon't forget the part where EVs are making transmissions themselves obsolete. there are still underlying gears, but there's just not a transmission in the same way.
- dragontamer 3y agoIsh. I think EVs in the long term will use two gears. 1-gear transmission seems... ill-suited. Its only possible on grossly-overpowered EVs (ex: Tesla). Economical cars like Leaf would likely benefit from a 2nd speed. Honda Accord Hybrids have a silly design: EV Motor is permanently on low-gear, while ICE-engine is permanently on high-gear. You could call it a two-gear system, but perhaps its two motors each permanently attached to a single gear without any traditional "transmission" (aka: system to change gears). Just a computer that is deciding to take more (or less) power to the ICE vs EV. ------------ EVs are well known to have poor highway cruising economy. I do wonder if a 2nd gear would help them out.
- fragmede 3y agoyou're right, I think. two gears to one electrical motor is still way simpler than some 8-speed auto edcvt hybrid monstrosity though.