https://www.motor1.com/news/743104/lucid-two-speed-electric-vehicle-patent/
Lucid Could Use Two-Speed Transmissions in Future EVs
The American automaker is interested in two-speed transmissions that allow electric motors to operate in ideal ranges at different speeds.
Of course you would be adding another component and and complication to an EV. Seems to move toward defeating the EVs have less components parts and simple to maintain argument.
OK, but there is a sweet spot for electric motors, as they spin up to between 25% and 75% of their max rated speed. Suppose you could give the EV another 20% of range by moving Gear 1 down a little to make slower speeds more efficient, match the crossover point, and move Gear 2 up a little to make higher speeds more efficient.
Would you be willing to trade âmore complexityâ (that you wouldnât see, but would pay for) for another x% of range? Give that range anxiety is one of the larger stumbling blocks for people, I presume there is some segment of the buying public that would.
I can only see that this escalates into multi speed transmissions added to an EV.
I believe we are up to 10 speed transmissions now on IC vehicles. Where does it end?
Just what I was thinking. âŚand that narrative about EVs having dramatically fewer parts than ICE vehicles fades away.
Steve
Maybe. But Lucid is a niche automaker that only sells a few thousand cars a year so they donât really matter much overall. If I see one of the biggies in EV (BYD, Tesla, Hyundai, etc) come out with a multi-gear vehicle I might think about it some more. I assume those larger companies would have studied the issue sufficiently to come to a conclusion that it is worth adding.
Sure, but youâd be surprised how many innovations came from smaller manufacturers before the big boys adopted it. Power windows, drum brakes, and others didnât start at GM or Ford. Sometimes theyâve âstudiedâ it but decided it was too much trouble because they already had their production lines tooled, suppliers set, and so on. Then comes along the feature (automatic transmissions!) and everybody has to have it.
I have no dog in this fight, I donât really care about this one. I will say this: in 60 years of driving I have had a transmission issue once. I have had a bazillion gas motor issues, from oil change to spark plugs to timing belts to,⌠well you get the idea. If they offered a transmission that bumped my range from 300 to 500 miles, and maybe someday it would require a lube or something, I would take that leap.
Surprised to see owners of EVâs here complaining about the possibility of changing the paradigm, even if only slightly, possibly for dramatic improvement. As I have read about the auto industry, it has never stopped changing: from the Model T to drum brakes to the WWII Jeep to Oldmobileâs Hydramatic, the ascent of disc brakes, muscle cars, fuel injection, blah blah blah.
Iâm pretty sure EVs are going to go through similar - even if very different - changes over the life of the industry.
Thereâs already a step down gear between the motor and drive train, since most electric motors for RVs spin at 10,000 to 20,000 rpm.
intercst
Engineers added multi speed transmissions to ICE vehicles along time ago to improve their miles/gallon. So why complain about EV vehicles doing the same thing. Seems logical to me. These transmissions are highly reliable, and they are low maintenance. We do not hear any complaints from ICE drivers about their transmissions.
I wouldnât be at all surprised. In fact, so many innovations come from small companies that the big companies often simply buy the small company to gain their technology (and not have to license it forever).
If this were the case, you can be sure, absolutely sure, that all the big EV manufacturers would add it!!!
I know Ford & GM has had problems with their transmissions.
Your articles note that Fordâs 10-Speed and GMâs 8-Speed transmissions had problems and some were software problems. EVâs are not going to 8 or 10 Speed Transmissions. Software problems are not transmission problems. Lots of multi speed car and trucks on the streets and highways without any transmission problems.
IMO the increase would be much smaller. I would say they might add 10%, but not 40%.
This is why most EVâs are advertised as having one-speed transmissions, because they do. But since it is a single speed there is no shifting to another gear ratio.
Multi-gear transmissions are all about efficiency and performance in ICE cars. There is zero reason to believe it would not boost both in an EV as well. In fact, Formula E race cars have multi-gear transmissions. Whether we want them or not is a different story. I do like not having that maintenance in my Acura ZDX. But I will admit, if it had a drastic impact to highway efficiency and range I would think twice about it.
I donât think thatâs the question here. Nobody (nobody who is informed) argues that it wouldnât boost efficiency. It is pretty much an obvious conclusion that if you can keep the electric motor in its range of âsweet spotâ for efficiency longer, that you wonât get more efficiency overall. The actual question is - is it worth adding the relatively complex component (compared to the general scarcity of moving parts in EVs) to the vehicle to gain that efficiency? If the big EV makers determine that it is indeed worth adding, they will surely add it at some point.
Thatâs why it would have to have a drastic impact to highway range before I would want one in my EV. Iâm not convinced it would, at least not yet.
It is worth noting the original Tesla Roadster (the one before Elon came along) had a two-speed transmission because without it it could not meet both the promised acceleration and the promised top speed without it. Gear it for top speed and it would not accelerate quite fast enough. Gear it for acceleration and it topâd out about 20mph shy of target.
All of these CVTs (i.e., continuously variable transmissions) appear to be crap. Even the ones from Japanese manufacturers.
intercst
The reason Lucid is doing it is because they like to âone upâ Tesla and Hyundai regarding efficiency. And they can do it because they only sell a few thousand cars a year, so the extra cost is buried in all sorts of other much higher overall costs. They really like to trumpet their status of âmost efficient EV availableâ as a core part of their strategy. But there are two problems with that part of their strategy:
But they really do make nice looking and good performing cars. But, of course, I would not buy one right now because they are still in danger of failing (as soon as Saudi decides to stop funding them, itâs over) and then you end up with a vehicle that canât be serviced and will essentially reach end of life at the first big problem. Like all the Fisker vehicles out there. I would only buy a vehicle from a company that I am reasonably certain will exist through the entire period of my ownership (which is usually about 10 years).
Also, I donât think the impact has to be âdrasticâ, even a 10% improvement in efficiency might make it worth adding ⌠if, and only if, the design can be made to be sealed, low to no maintenance, and extremely reliable.
This paper suggests that the improvement would be on the order of 2% to 20% on various driving cycles.
Multi-speed Gearboxes for Battery Electric Vehicles: Current Status and Future Trends
A difference of 20% in energy
efficiency results was found between the worst and best
combined electric motor and gearbox. Since EVs typically
utilize electric drivetrains, which are highly optimized for
efficiency, it is likely that no more than a few percentage
points of range could be gained with a multi-speed gearbox.
To conclusively determine the benefits of multi-speed
traction systems, it is imperative that more research be done
using production electric drivetrains as a benchmark.
See chart on page 13 where most of the possible gains are 2% - 7% on the US EPA cycle
Mike
Mike