Well, magnet-less separately exacted synchronous motors with the exact same architecture have existed since ... checks notes ... over 100 years, so it took me a while to digest the whole marketing fluff where they use an entire page to explain how an electric motor works, and see what's so special about this besides the claim that it's now "up to 90mm more compact axially".
It seems like the big innovation here is that it doesn't use slip rings and brushes anymore, and the power to the rotor is now transferred via induction coils:
"energy is transferred inductively, i.e. without mechanical contact, into the rotor, generating a magnetic field by means of coils. Thus, the I2SM does not require any brush elements or slip rings. Furthermore, there is no longer any need to keep this area dry by means of seals. As with permanently magnetized synchronous motor, the rotor is efficiently cooled by circulating oil."
The good part is there's no more brushes to wear out and no dry seal needed so the motor can now be oil cooled from the inside as well, but to me it raises the big question about the power losses incurred by the energy that's transferred to the rotor via induction versus the previous direct contact via brushes and slip rings.
In an ideal brushless drive, the strength of the magnetic field produced by the permanent magnets would be adjustable. When maximum torque is required, especially at low speeds, the magnetic field strength (B) should be maximum – so that inverter and motor currents are maintained at their lowest possible values. This minimizes the I² R (current² resistance) losses and thereby optimizes efficiency. Likewise, when torque levels are low, the B field should be reduced such that eddy and hysteresis losses due to B are also reduced. Ideally, B should be adjusted such that the sum of the eddy, hysteresis, and I² losses is minimized. Unfortunately, there is no easy way of changing B with permanent magnets.
Essentially, this new tech combines the best of Permanent Magnet Brushless DC and Induction motors. It allows you to change the magnetic field B without contact.
The losses in the shaft coils are low when B is low so the gains in efficiency for an "eco mode" would be excellent as you modulate B for low torque and you would still retain the ability to crank up the power in a "sport mode" at the cost of efficiency.
> Unfortunately, there is no easy way of changing B with permanent magnets.
There’s the old semi-permanent magnet trick, although this only allows a couple of discrete field strengths, not continuous tuning. Basically, a neodymium (or other hard) magnet and alnico (or other soft) magnet are put in parallel, surrounded by a pulse winding. A pulse can flip the magnetization of the alnico, but not neodymium, so you get field strengths of either neo + alnico or neo - alnico. (This is most often used sized for similar strengths to turn a “permanent” magnet on or off, but can be used in non-equal strengths as desired.)
Exactly. The B field can be cranked up for short a duration to maximize torque. The rotor could also have much lower inertia.
I sketched out this same topology, with inductively coupled coils for the rotor's magnetic field. If you don't need the fields to reverse (they wouldn't with a magnetic field). Then you could still have small PMs in the rotor with a coil to provide boost field for additional torque during acceleration.
Brushes and slip rings seem like they would be more efficient, but they are adding friction and sparking that isn’t part of this, and as they wear become less efficient. BLDC showed that induction wins through one conversion, but this is making 2.
Simple napkin math: If you compare BLDC to Brushed efficiency. Best BLDC is 90% efficiency and best brushed is 80%. Even if the inductive rotor loses as much energy as the complete BLDC motor, it would still perform on par with a brushed motor.
I don’t understand why this is being downvoted? Is this a terminology thing? I design my own brushless motor controllers. A brushless motor operates by generating a magnetic field in fixed coils and using that magnetic field to directly act on magnets.
Wikipedia defines magnetic induction thusly: “Electromagnetic or magnetic induction is the production of an electromotive force (emf) across an electrical conductor in a changing magnetic field.”
So basically using a changing magnetic field to create voltage in a conductor. While it is true that induction occurs in a brushless motor as a secondary effect (the rotating rotor induces back EMF on the stator coils), the primary mechanism of movement is a magnetic field physically acting on permanent magnets - no induction involved.
This is distinct from an AC induction motor, about which Wikipedia says: “An induction motor or asynchronous motor is an AC electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding.”
Basically in an induction motor, induction is a required effect for the operation of the motor, rather than a side effect as in a brushless motor.
So while induction occurs in a brushless motor, if induction could be magically disabled the motor would still work. This is not true for an induction motor.
Indeed, BLDC doesn't use EM induction to excite the rotor, instead it uses directly macroscopic magnetic force due to current in stator acting on the permanent magnets in the rotor.
The EM induction is present in the winding of the stator, and to some extent has to be present, to keep the current there low enough, otherwise we would get locked stator situation, and the winding would burn out.
To be fair, is practically on one of the first lines of the press release: "...In contrast to the magnet-free concepts of so-called separately excited synchronous motors (SESM) already available today..."
That's the normal/traditional advantage of "brushed" motors vs synchronous motors, but the brushed motors have the massive disadvantage of having a mechanical contact (the brushes) that wear off, need to be sealed, etc. The advantage here is that it behaves like a brushed motor, but without the brushes!
Out of interest, what could make such a design better than a traditional inductive motor? Such motors already suffer inductive losses, and do not need slip rings or brushes, and presumably do not an additional set of windings to transfer power to excite the stator?
Just could the two sets of coils be optimized for their own purposes?
Inductive coupling in an ASM is at the drive frequency (hundreds of Hz), inductive coupling in an inductive electrically excited SM can work at an arbitrary frequency, e.g. 100 kHz. You can also see in the ZF release how small the coils for transferring the excitation current are compared to the main windings, they are the small rings on the left side.
>what could make such a design better than a traditional inductive motor
Traditional induction motors, compared to these with wound rotors, are heavier and bigger in size for the same power output, and have less efficiency especially at starting/low-speeds.
So then it comes down to cost? If this is cheaper than a motor and vfd, then it's still a win?
Source: the one time I restored a massive JT Towsley jointer and had to get a vfd for the giant motor I had to put on it. In other words, I have no idea what I'm really talking about.
Oh I was just going to comment that those looked like some sort of brushes and thus that would negate other advantages, but after reading your comment and carefully reading the notice yeah that is definitely great! Induction coils instead of brushes for the rotor current def seems like a key advantage/development.
The animation seems to show that the rotor has a DC (ie. constant) field. That is easy to do with slip-rings and a DC current source, but with any induction mechanism, there must be a rectification stage on the rotor. They don't show any of that.
I'm wondering if performance could be improved by controlling the polarity of the rotor coil fields, to push against the stator-induced ones. Since some semiconductor rectifiers are necessary in the stator, it doesn't sound much more complex to control the polarity. Part of the control logic could be handled before the inductive power transfer mechanism, by modulating the frequency, though it gets complex as you probably want to tune the resonant frequencies of the sender and receiver.
Wind turbines work that way. Early wind turbines had to mechanically rotate at a fixed speed to match the grid. With modern ones, the field is sometimes electrically rotated to adjust for rotor RPM. This can be done quickly as the wind changes. The range of control is not large, though. This is a quick adjustment made electronically until the blade pitch can slowly be changed by motors to re-tune the wind turbine for the current wind speed. Look up "doubly fed induction generator".
Interesting to know, thank you. They seem to mostly use this to adjust the frequency of the induced current in the stator, as they control the rotation speed of a "virtual rotor" (rotation of the rotor + rotation of the magnetic field around the rotor).
That's indeed similar, but in the wind turbine use-case, the stator is passive. A direct application could be to tune the torque/speed response, or improve motor weight by reducing the number of coils on one of the elements.
It's common for large, power station sized, generators to have that. The field windings are on the rotor, and the heavy power comes out from the stationary armature windings. To power the field windings, there's a smaller generator as part of the machine, but it's the other way round - stationary field, rotating armature producing power. The output of the smaller generator is rectified by diodes on the rotor to provide DC power for the main rotating field. No commutators or slip rings. No wear, no arcing.
Yes, but these ones with externally excited wound rotors have the advantage of more torque and efficiency at compact packages but have had the disadvantage of brushes that would wear out, create carbon dust and electrical noise.
So it's the `I2` from the `I2SM`-name which is the key part, referring to the induction of current into the outer coils, and then the magnetic induction to create the forces.
> The good part is there's no more brushes to wear out and no dry seal needed so the motor can now be oil cooled from the inside as well, but to me it raises the big question about the power losses incurred by the energy that's transferred to the rotor via induction versus the previous direct contact via brushes and slip rings.
Slip ringed motors can be perfectly oil cooler as well. And you will need oil seals and drains in under any circumstances you use oil cooling.
The most usual kind of motor with permanent magnets, is just a synchronous motor, where, in order to remove the power supply needed by the rotor windings, the rotor windings are replaced by permanent magnets.
Here, in order to achieve the same brushless operation like when using permanent magnets, the rotor windings are kept, but the electrical current needed by them is transmitted to the rotor wirelessly.
For this to work, I suppose that the rotor includes some kind of semiconductor rectifiers and the rotor current is induced at a frequency much higher than the rotation frequency.
This should indeed have characteristics similar to the permanent magnet motors, except that it is not clear if the energy efficiency can be equally good.
A permanent magnet rotor is equivalent with a rotor having superconducting windings, so it has no losses due to the electrical excitation currents (though it may have losses due to other causes, e.g. hysteresis and eddy currents).
This motor will have extra losses in the copper windings of the rotor and in whatever kind of rectifiers it uses.
Nevertheless, perhaps these extra losses are small, so the efficiency can be much higher than that of asynchronous motors (like initially used by Tesla) and only a little lower than that of the permanent magnet motors.
> except that it is not clear if the energy efficiency can be equally good.
There are potentially ways energy efficiency can be better...
It's possible to produce stronger (ie. more flux density) magnetic fields with electrical currents than with neodymium magnets. Those stronger fields mean flux paths can be shortened and (for the same mass of copper), wires can be shortened and resistive losses reduced.
However, I haven't done the math to see if those effects are of a significant enough magnitude.
In a brushless DC magnet rotor, there is little energy loss, the magnets aren't very conductive.
Here, we have additional current and newly introduced Joule losses in the rotor. It is not clear that these can be kept low enough so the result is as good.
Stronger magnetic field due to high current in the rotor does not directly imply higher efficiency, it only directly implies higher torque, which gives the car higher acceleration. We don't need to increase this strength, current motors are plenty strong. This top torque mode of operation usually goes with decreased efficiency, due to high currents and high Joule losses. The best efficiency is likely to be achieved when ohmic and friction losses are kept low, thus currents as low as possible everywhere, induction coupling frequency dynamically governed to be at the optimal value dependent on the angular speed.
The only obvious advantage of the marketed motor is smaller size and likely lower weight. I'm afraid price will be a disadvantage.
It's just an inductively excited synchronous motor; this is a decades-old design being brought out again to satisfy the current trending buzzwords in the industry.
(The most powerful motors have always been wound-field designs, since huge permanent magnets are extremely difficult to make and even more difficult to handle at all.)
All the inductively excited synchronous motors described in those patents work due to including semiconductor rectifiers in the rotor.
It is likely that today this concept from more than a half of century ago can be revived at a much higher level of performance, due to the present ability of making optimized designs and due to the fact that now much better rectifiers are available, e.g. silicon carbide Schottky diodes.
I suspect this ZF motor is like what is described in this paper [1]. An air gapped transformer is used to transmit power to the rotor and diodes rectify it. See Figure 1.
This [2] appears to give a good summary of PSM vs ASM vs EESM and introduces iEESM (i is for inductive excitation instead of brushes, sounds like the ZF motor) at slide 14.
[1] Design of Inductive Power Transmission into the Rotor of an Externally Excited Synchronous Machine
It does not matter whether the driver generates AC or chopped DC, when passing through the gap between stator and rotor, any DC component is removed.
To provide the DC component needed by the excitation current, a rectifier is required, or at least a nonlinear impedance, but the latter would have a lower efficiency, due to higher AC components that would cause losses without providing useful torque.
A brushless synchronous motor which relies on an electric excitation current in the rotor (i.e. not on permanent magnets, hysteresis or variable reluctance) cannot generate the required excitation current when only linear circuit elements are present in the rotor.
> The Consolidated ZF Group is represented with 168 production locations in 32 countries as well as 19 main development locations in nine countries. In fiscal 2022, ZF reported sales of €43.8 billion with approximately 165,000 employees worldwide. The company spent 7,8 percent of its sales on research and development in 2022.
I work for zf. There are two large plants in south carolina. One that supplies the bmw plant here and another that makes transmissions for most of the major auto manufacturers and parts for tesla. We have a few thousand employees at the plant I work at. They are investing a fair amount of money and time in setting up more manufacturing here(US). Fun fact I get to ride a tricycle around the plant.
And all Zf transmissions had a major design fault up until the current 8 Speed. Now they are pretty good. Not only European cars use them, many Chrysler/Dodge/Jeep/Ram cars have ZF 8 speeds in them.
Yes, it is that Zeppelin Foundation. 1947 the old militarist Zeppelin Foundation got dissolved and a new one got formed. It is not exactly „owned“ by the city, but controlled by the city and the city is the benefactor, but not for the general budget, but for Science, Education, Art, Culture, Sports and some more.
The foundation ownes another Company: Zeppelin GmbH with ~10000 employees and a revenue of 3.7B. So also not exactly small. Zeppelin GmbH is the “real deal”. They built the Zeppelins back in the day and with their daughter Zeppelin Luftschiffbau GmbH they are building the new Zeppelin NT. the 3 current “Goodyear Blimps” are not some generic Blimps, but modern Zeppelins.
The commenters saying that this is old news and that magnet-free brushless motors have existed for a long time miss the main point. ZF claims to have one that is competitive with traditional designs utilizing rare earth materials.
Even ten to fifteen years ago the effort German automakers put into saving a milligram Dysprosium here and there - not only in the drive motor but every electric motor in the vehicle - was insane. I'm out of automotive for a couple of years now, but I can only imagine that this pains must have increased dramatically.
Because of all this effort, a motor without rare earth metals would only have to be nearly as good as the competition to still be a huge deal.
I always had a strong interest in security and that's the direction I developed even when still in automotive. When the opportunity came to work for a security company I switched.
It still boggles my mind how much power a modern electric motor gets from such a small package. I'm so used to big engines weighing hundreds of pounds making maybe a couple hundred horsepower. Now we have electric motors making quite a lot more (and not to mention insane torque) that I could easily pick up with my hands.
There are motors with peak efficiency about 90%. The first one of those I ran into was fifteen years ago. Which means not only is it possible but the patents will have expired, if not now then soon.
Power density has gone almost too far. There’s one pancake motor I’ve seen recently where the shape of the enclosure is dictated by mounting concerns. You have to be able to mount the motor to something it can’t tear apart. If they shrunk that motor another 20% then it would be half housing. I’m not sure where you go from there. Thinner? Motor per wheel?
Motor per wheel sounds interesting. As I understand it’s not ideal for handling because of unsprung weight. Maybe that will change? Would be very excited about the prospect of converting cars to purv (somehow)
Does anyone have a raw materials cost breakdown of motors? Are the neodymium magnets actually a big chunk of the cost? Or is it more of a "we'll get government grants for inventing a type of motor that doesn't require a material that China has strategic control over".
I know press releases never describe anything that's actually novel, but it looks like they're just describing an asynchronous induction motor? I'm wondering if this release is implicitly pretending that some "low slip ratio" motor is "basically" synchronous
Just guessing, does ZF mostly put out induction motors, and they need to make them look less unfashionable so that people choose them for new designs?
ZF is generally known for gearboxes, a huge amount of manufacturers use their transmissions in their cars. New corvette uses a zf 10 speed I think, same with vw and BMW.
I saw a video recently of Tesla bragging that they had a new motor with only 3(?) powerful magnets in it.
This makes me think that less magnets is a good thing - can anyone explain to me the reason to use less magnets in motors? (To me it just seems that less magnets would make it harder to spin with a magnetic field, but I'm no engineer).
If having fewer magnets means less rare earth consumption for the same performance, then that's a benefit in itself - the same one as is being claimed for this motor.
I think it just dictates the number of poles the motor has? The fewer the poles the less torque it has, but higher RPM. Either way you have to gear it down for EV use, so I suppose it doesn't really matter much in the end, except if it makes the rotor less likely to explode.
I would've expected very high pole counts to be more practical though, since a lower RPM is more manageable in terms of bearings wearing out. On the other hand, steppers have a high pole count and their efficiency is crap so maybe they can get more power out with fewer poles.
Maybe not your experiences, but, to me, their transmissions:
* hastened the inevitable transition away from manual gearboxes in cars
* gave a bit of a “last hurrah” to ICE powertrains in general
Quick-shifting, gobs of gears, lockup torque converters, and reliable to boot. I don’t hear the word “slushbox” being thrown around like it was previously to describe automatic transmissions. And I credit it mostly to ZF.
As an owner of an M4 with the ZF 8 speed, I can attest that it’s not a slushbox. It’s completely changed my mind about how a manually-shifted auto transmission with a torque converter can behave, and I don’t see any reason to ever go back to a true manual. My only real complaint is that 8 is too many gears so they are naturally narrower and the car ends up being designed around keeping your engine speed in a fairly small band, and low end torque suffers.
This is about their automatics, but parts availability (especially aftermarket) and service information is relatively scarce and expensive compared to e.g. GM/Allison. Their bus/truck transmissions also shift quite roughly, almost like a manual.
ZF is what I'd consider very stereotypically German engineering: optimised for efficiency and cost, at the expense of longevity and serviceability, with very little margin for overload.
There's a difference between what the layman has been led to believe by Big Deutschland, and the reality experienced by those who actually have to deal with German designs. A lot of them are interesting and "elegant" on paper, but the good experiences usually end there. It feels like the fun factor of the design process is what's prioritized most heavily, which is great for the designers (and I don't say this facetiously; the fun is the #1 reason to do it at all, and I'm glad they make a living off it), and not-so-great for the poor fucker that has to repair a VW.
That's not to say that they always shit things up. I'll take Wago nuts over American style ones any day of the week. VW's VR6 engines are a simplification that would probably make my life a lot easier if I didn't have to buy them with the rest of the VW vehicle attached. There is so much more vision coming out of Germany in industrial controls than anywhere else it's outrageous. Life has its ups and downs, I guess.
> In contrast to the magnet-free concepts of so-called separately excited synchronous motors (SESM) already available today, ZF’s I2SM (In-Rotor Inductive-Excited Synchronous Motor) transmits the energy for the magnetic field via an inductive exciter inside the rotor shaft. This makes the motor uniquely compact with maximum power and torque density.
Permanent-magnet-free would be more accurate, this is sort of like a BLDC motor, except that if I understand this correctly they use some kind of wireless charging to power coils on the rotor? Doesn't wireless charging have only like 70% efficiency?
A regular BLDC motor is already using induction. See this video.
The 70% number you are referring to is for a flat coil through a much greater distance than would be needed here. For the new design, I imagine another set of coils inside and separated from the rotor, and the magnets on the rotor replaced by a simple ring. The induction coils would need to be offset to produce torque on the ring. Yes, it would be less efficient because you are using power to produce the magnetic field. However, no rare earth metals are required.
There is EM induction happening in the stator coils, but it is not substantial to how the motor effect comes about. This effect is due to magnetic force of the coil poles acting on the permanent magnets, no induction is needed to create this effect (thus it exists even when instantaneously, EM induction in any one coil is zero).
This sounds like it's an induction motor where the inductors are on the spinning part (the rotor - or maybe in both?)
People are downplaying this, but I'm not so sure (yes I know about synchronous motors, etc), but there sure it is covered in marketing fluff (which is not wrong per se - if tesla passes gas people would have been all over it)
The obvious comparison is to an AC (asynchronous) induction motor, which also has no magnets and couples energy into the rotor inductively. These are widespread. I didn’t see anything on the website about how their design is better.
There’s no doubt in my mind that EVs are the future, it’s just hard to fault people who don’t want to pay more for an objectively worse overall product.
For the record, I think within the next 10 years that will change but I don’t think 5 ton EV trucks are the answer.
The whole story has salient parallels — parts suppliers were either reticent or inexperienced, fuel was cheap but not widely available, motors were slow, investors put money in before the market was there, founders lamenting the state of the modern laborer, early adopters stuck needing parts for vehicles orphaned by suddenly defunct manufacturers, and the guy getting all the money and attention is a wealthy idiot making self-crashing death traps who relies on free advice from his witless fans to avoid failure and profit. There's even a cameo from early EV manufacturer Electric Vehicle Company in 1899.
Tangentially, this is evocative:
> In the uncertainty of what the public would want, a great many strange contraptions were put together. Joseph Barsaleaux, a blacksmith of Sandy Hill, New York, built a motor horse. In his device, the horse moved on a single wheel about two feet in diameter, with the wheel attached to the shafts just as was a live horse. Reins attached to the mouth of the horse served as a steering gear, because the machinery was inside the horse and had to be regulated some way. The contraption weighed about 550 pounds, had a cruising speed of six miles an hour, and attracted some serious attention.
EV makers should probably stop trying to make mechanical horses — EV motors and cars that aren't competitive with ICE equivalents — and find a form factor that better suits both the market and the current state of the technology. Class 2 ebikes and small carts feel closer to that answer on short runs, but the long-haul equivalents are still missing.
Hell, Winton in this story is a bicycle manufacturer who makes his first horseless carriage from bicycles.
I don't disagree, but there's one major difference at play here. Those early horseless carriages--and maybe even the first ~9 decades of automobiles--were objectively simple, maintainable, rebuildable machines. Many examples from that early era are still running. None of them had proprietary computer systems, delicate plastic parts, etc.
I think it's substantially less likely that there will be any vehicles from the first couple decades of this century running 100 years from now. And it's an important part of sustainability, cost of ownership, etc.
It's hard to see the point in owning a vehicle from this century unless manufacturers start building them to be good transportation tools instead of what they appear to have become--a means to sell a financial instrument (a car loan), an ads serving platform, and a data collection mechanism. For me personally that is really the biggest barrier to owning an EV.
That doesn't disagree with what he's saying though; it's still in a transition phase. Range loss issues from cold weather and/or towing are still a concern, inability to charge at home is a concern, large upfront costs are still a concern, the weirdness of fast charging stations is still a concern. They're solvable issues and in time will be, but they're issues lot of people don't want to deal with while things are still in flux and don't see enough value in paying the cost of being an early adopter.
We had a friend end up with an ev rental they didn’t ask for ans holy shit did that ruin her weekend. Technology Connections has been talking about it recently. Tesla is winning as a power delivery standard mostly because third party charging networks are such a giant clusterfuck.
She couldn't find a charger that would charge in under six hours. She was only here for 3 days. 12 hours of charging is most of your waking hours.
She plugged it into my house the first night. We realized the next morning it wouldn't hit 100% until after she was due to return the vehicle. She picked up the car at the next airport over and drove the scenic route to our house. All of the chargers on that route were adding miles slower than 1 per minute, which means one hour of charging per hour of driving. She barely got here before sunset.
I have an ancient electric car with low range, so I signed up for all the services. They by-and-large absolutely suck, broken machines, broken websites, broken software, bag of broken in a bucket of broken.
I can understand how that could ruin someone's trip.
... except the EV is objectively better, not worse.
Literally the only thing an ICEV can claim superiority on is refueling time. And even that comes with big caveats: it only applies to road trips, and even then it's unrealistic. Around town, refueling an EV takes essentially zero time, far less than an ICEV. On a road trip, the ICEV does refuel faster, but in real life road trip stops are typically 15-20 minutes anyway, and that's enough to refuel a modern EV.
What's exciting is that while EVs are already objectively better, the underlying technology is still evolving quickly and the future is very bright. We're already able to do things with EVs that aren't even possible with an ICEV, and this is just the beginning.
Now, go live in a cold climate for a while, a little outside of a city.
There’s no single dimension of experience to rate these things on. I know several people who want an EV, but have been, fairly, dissuaded by their EV owning neighbors, especially when “per dollar” comes into play.
I'm not EV fudster, but for me gasoline cars are better in every aspect. May be except maintenance (I'm not sure, but I expect that I don't have to change oil every year in an electric car). I don't have money to buy two cars, so I need one versatile enough car. I can bring 100L gasoline with me to add 1000 km range on top of existing 500 range. I can charge it within 5 minutes, not 5 hours. It does not get worse with every year, because there's no degrading battery which costs like half a car. Probably the only thing that's better about EV is that electricity is the same everywhere, I can't charge it with bad electricity mixed with water in the old station, LoL.
Electric cars probably are the future, but I don't like this future. They don't have a soul.
If you carry 100L of petrol around in your car you must admit you are a very niche segment.
I've driven in dozens of countries, sometimes very far from fuel stops, but I've never once had the need to carry any additional fuel inside my vehicle. I think the furthest I can ever remember being from a petrol station is about 120 miles.
> I can bring 100L gasoline with me to add 1000 km range on top of existing 500 range
This is the big advantage.
> not 5 hours
This one is mixed. You can charge the EV at home for ordinary use. That's better.
For road trips, you can use DC fast charging to add a bunch of range in 30 minutes. This is worse, requiring combining charging and meal stops.
PHEVs are a decent compromise, though: you can do basically all of your driving electrically, and then burn a little bit of gas on road trips.
> It does not get worse with every year
Sure gasoline vehicles become more maintenance heavy and terrible over time. EV degradation is probably around 10-15% range lost after 5 years typical today.
> May be except maintenance
Odds are you don't deal with brake pads anymore, and yes, no oil changes. The sheer torque of most models feels like a spaceship when you press down the gas pedal.
>> I can bring 100L gasoline with me to add 1000 km range on top of existing 500 range
> This is the big advantage.
No, absolutely not. Who brings 160 lbs of gasoline with them anywhere? That's twice as much as an average cars gas tank. How many people do you know that have ever brought any gas on any trip ever?
The "advantage" of being able to drive 12+ hours without taking a couple hours to charge is absolutely ridiculous. It's not something people do or should do. The only reasonable circumstance is if you're on a camping trip or something, and somehow driving hundreds of miles without passing a source of electricity- in which case yes, use a gas/ethanol car.
In my honest opinion, it's a ridiculous demand that you should be able to drive 800 km without taking more than 5 minutes to stop. It's minimum 6 hours of driving, and like 30-40 minutes of charging. It's petulant to complain about that like it's a real issue.
The real advantage is cost. It costs a lot of money to get a large battery that can charge quickly, when a $20k Civic can do it. Smaller the EV, the slower the charge, and the more inconvenient it is.
> The "advantage" of being able to drive 12+ hours without taking a couple hours to charge is absolutely ridiculous. It's not something people do or should do.
One person shouldn't drive 12 hours, but it's not bad for two people to split. It's not unreasonable at all if you have three drivers.
Yes, you'll probably stop somewhere to eat and use the restroom. If that somewhere happens to have decent food, and a fast charger, and the fast charger doesn't have a line longer than your mealtime, then an EV would probaly work out. If those stars don't align, your long day of driving got even longer.
I don't bring gas cans on long trips, because gas stations are ubiquitous; but I have enough gas equipmemt at home that I keep them at home, and I use them to fill up my cars at home regularly to keep the gas fresh, and avoid paying the markup of my nearest gas stations.
PHEV is a better choice than either IMHO. You get two year maintenance windows, you get long distances between fueling, you can use electric for local trips if it makes sense, you can live in an apartment with no charging infrastructure, you get reduced brake wear, you get a lot of low end torque if that's relevant to you. You probably lose out on cargo space though, cause PHEVs tend not to have handy places to stash the batteries. Oh, and internet people will argue that it's the worst of both, and you'll have to ignore them.
It's not necessarily at one stretch, it could also be for several days camping away from services.
One of the places I've long wanted to go is about 100 miles from the nearest town with a gas station, but the roads are particularly rough so I don't expect to get highway mileage or anything close to it. In my past off-roading I've gotten roughly half my highway mileage, so let's say it costs 200 "miles worth of gas" to get there.
If it takes 200 miles to get in, it also takes 200 miles to get back out, plus some margin for error, plus whatever I burn while I'm there. A few days of cooking and stuff can burn a few gallons, more if I'm also running the fridge, which is really nice on a long trip. Add that I might want to visit a few sites over a few days, and I could easily see needing more than my existing 500-miles-in-ideal-conditions range.
It's trivial for me to carry another 10 gallons, which doubles my highway range to 1000 miles, and that's with one of the most fuel-efficient hatchbacks on the road. A larger vehicle would need quite a bit more.
I simply don't know a way to do that with an EV.
Now admittedly that's a contrived example, but it's a just-slightly-more-extreme version of some real trips I take from time to time, and it's a trip I do honestly plan to take one of these days.
> The only reasonable circumstance is if you're on a camping trip or something, and somehow driving hundreds of miles without passing a source of electricity- in which case yes, use a gas/ethanol car.
But is it, actually, the only reasonable circumstance? That's an exceptionally strong claim.
To be clear, I wouldn't carry 160 lbs of gasoline with me, but I've absolutely done drives where I've stopped for gas twice and been driving >99% of the time, which electric cars can't do.
> The "advantage" of being able to drive 12+ hours without taking a couple hours to charge is absolutely ridiculous. It's not something people do or should do.
I pretty regularly drive between Washington, D.C. and northern New Hampshire. That's about a 9hr drive under good traffic and weather conditions, 575mi. My truck gets about 13.5mpg and has a range of around 300mi, so I have to stop for fuel once. It's nice to get out of the car every 4hr or so anyway. If I was driving, say, a Rivian that gets ~400mi/charge I would also only have to stop once, but the stop would take about an hour and a quarter [1]. I could probably live with that, and I'd appreciate not burning as much dino juice.
However, I recently did that trip with the truck totally freighted, towing a two axle trailer. I got 9.5mpg, which is about 65% what I get empty, putting my range at ~200mi/tank. I had to fill up twice. A Rivian under similar conditions will be getting about 260mi/charge. That means I'd have to charge twice, adding 2.5hr to what's already a 9+hr trip.
Another thing my truck can do is go off road. It has a mild suspension lift, and locking differentials front, center, and rear. It runs slightly taller than stock tires to give it more ground clearance. I can roll over 2-3ft high rocks without having to think too hard about it. Under these conditions, I expect to get even worse than 65% of my empty highway mileage. 50% is common, and it can even be as bad as 35% in really technical terrain. Ignoring the fact that the Rivian would likely break if I tried to take it places my truck can go off road that translates to something like 150-200mi/charge. And if you're actually taking it off road you better plan for plenty of reserve, because there aren't any chargers there.
> Who brings 160 lbs of gasoline with them anywhere?
Someone who wants to get there, most likely. If you calculate you need to make it a certain distance, and you know your expected fuel burn rate, then you can count up the number of jerry cans you need. In this case they needed 5 of them.
So it's a question of capability, right? My truck is in some ways more capable than the EV alternative. One capability I have is to be able to throw some cans in the back and extend my range. Another capability I have is being able to travel long distances under adverse conditions.
Crucially, though, the capability my truck has that the competition lacks is I can fix it and maintain it without having to hire a specialist. It has simple, impeccably engineered field serviceable systems.
And it cost 1/6 what a Rivian would.
If someone makes an EV with these capabilities, I'll buy it, even if it does cost as much as a damn house. Until then, I'll stick with my old truck.
10 to 80 leaves me 70% effective capacity, so that's 0.7 * ~400 = ~280mi/charge. This would mean on my 575mi drive I'd spend 3 * 40min = 2hr charging. So it'll take me 11hr to do a 9hr drive.
Let's say I was towing. That would give me ~180mi/charge. On the 575mi trip I'll have to charge 4 times, so 2hr40min.
So that's actually worse than I calculated before in both cases.
EDIT: it seems to me this technology isn't ready for production yet. Or, at least, it's best suited for subcompact vehicles that don't get loaded heavily.
EDIT2: I get it, though. If I lived in a city or a suburb and used my car exclusively as a grocery getter + commuting rig, it might make sense to run an EV--if there was a good one available at a reasonable price. But that's the other thing. They're all expensive, unmaintainable, and packed full of useless infotainment garbage and a whole bunch of plastic--just like everything else built this century. So really what's the point of using electrons from the grid instead of gasoline from the pump if I have to get a new car every 5-10yr? Instead, I'll maintain my (currently) 25-30y.o. vehicles s.t. they'll last a further 20 years thereby having prevented something like 10 cars from ever having to be built in the first place. And I own them outright, so no car payment.
> You wouldn't start full? Using your numbers, 250*.9 + 180 + 180 makes the trip in two charges.
Sorry, you're quite right. So towing it'll be 2hr of charging for 9hr of driving, empty it'll be 80min for 9hr.
I don't really buy the meals argument, though... I can't recall when I've ever stopped for a meal while driving somewhere. Even on long road trips (like 4k+ mi) I prefer not to eat whole meals during the day as I find they make me less alert and sleepy, especially given the lack of physical activity driving entails. That's not to say it would be impossible, or bad even, to take a few half hour breaks during a day's drive. I hope some day a car manufacturer decides to make a simple, decent, 25+yr vehicle again. No plastic, repairable, maintainable. I'd love to buy one.
> Let's say I was towing. That would give me ~180mi/charge. On the 575mi trip I'll have to charge 4 times, so 2hr40min.
You wouldn't start full? Using your numbers, 250*.9 + 180 + 180 makes the trip in two charges. Stopping a couple of times for meals makes it take no net increase in time.
edit: It definitely doesn't work for everyone and every use case, but it's much better than you calculate. The EV road trips I've taken have been slightly inconvenient but the day to day convenience of at home charging makes up for it.
Also I don't understand why you're continuing to edit your message long after I replied.
Furthermore: for all the whining people do about "sitting around waiting for it to charge", those people conveniently leave out all the time they spend driving to/from and waiting at a gas station...whereas many EV owners just get home and take about 30 seconds to plug in.
So, for the tradeoff of having to wait ~20 minutes instead of 5 to fuel up on a long trip, you get to not spend ~5 minutes every week or two driving to a gas station and filling up.
Most Americans don't even drive enough per day to make it necessary to have level 2 in-home charging.
Those are all pretty tired arguments, and already debunked thoroughly. I spend a lot less time refueling my EV than I ever did on my ICEVs. And it doesn't take me any longer for a road trip stop than it did before, I always took 15-20 minutes to take a leak and stretch. Almost nobody does a 5 minute in-and-out on a road trip. You might, but you also carry 100L of gasoline with you, which is very uncommon. And as someone who's owned vehicles with gas tanks in the passenger compartment, I strongly recommend against it.
> Electric cars probably are the future, but I don't like this future. They don't have a soul.
Now you're being honest. You don't like them because they're too quiet. That is a valid opinion.
I live in a large city, I drive a small car and I only drive about 3000 miles per year. Right now gas is ~$5.35/g at the station down the street and it's ~0.18/KW. It takes 114KW to "fill" a Tesla S, so ~$20.50. The range on a Tesla S is 405 miles, so ~19.75 miles /dollar. My VW gets ~30MPG or ~5.6 miles/dollar. The numbers make sense as does the range, I don't know many people who drive over 400 miles per day ever. The issue as I see it is quality and price, Tesla is sub-Kia quality at BMW prices. Honestly I think a lot of people are just looking for an excuse not to move to an EV, just like they did with going to unleaded gas or using LED bulbs. Everything is going electric and people that can't see that are just willfully blind -the Saudis knew this years ago, I'm not sure why so many people think it's a surprise.
As far as soul, what is stopping auto makers from making cool looking cars, honestly I don't know. One of the things I thought was cool about the Tesla 1 was that it was a good looking convertible and not something that looked like a rolling doorstop (Prius). Maybe EV will usher in a new generation of car makers that will make good looking cars again, we can hope.
> not something that looked like a rolling doorstop (Prius)
Cars are shaped the way they are today for aerodynamic reasons.
> I live in a large city, I drive a small car and I only drive about 3000 miles per year.
Hopefully you can see that what works for you doesn't work for everyone.
Living in a city and only driving 3000 miles a year... Have you considered not owning a car at all? :)
Given your figures, at 3000 miles per year it would take 108 years for the improved fuel economy of the Tesla S to pay for its added cost over a Kia with comparable build quality.
This is part of the reason you don't see the improved $/mile being so heavily advocated for EV's especially high end ones: The improvement isn't enough to pay for the added cost, unless you're a very heavy user and heavy users have more range, recharging locations, and recharging time concerns.
A significant difference is that I can get around that range for a few grand, with an ICE. It’s disingenuous to omit initial battery/costs of ownership from these calculations. $/mile the actual metric (and that’s even difficult with the road tax evasion that EVs currently enjoy).
I own an EV, and love it, but I also suspect it’s going right to the dump after the battery gives out.
I find the ability to understand the concept of a car's "soul" to a very reliable way to separate them out.
Why? Because "soul" doesn't mean the immortal soul endowed by our Creator. It refers to the feel and responsiveness of a car. The car's personality, if you will. It refers to every unique behavioral trait that the car has acquired through its design and life been driven.
On my old truck the clutch would feel different after my wife drove it. It took a few miles to get the feel back. It drove better with a couple hundred lb on the bed. On my '13 golf I can feel a slight "give" on the steering from wear. I can feel the car and drive it through a corner with the wheels slightly squealing [1]. Thats the edge grip. On the KIA I can feel the difference in the engine and transmission (especially) behavior before and after the oil has warmed up. On the Golf, the shifter is "lazy" until she warms up.
Within 10 miles of getting a new set of tires I know if I hate them or love them. I get a feel for their limits.
I hate renting cars. Despite the low millage, they feel worn and lose. I also feel like a fish out of the water in a car that is not mine.
As you add mechanical/electrical complexity these various feedbacks from the car are washed away. Professional drivers hate these aids. This is widely known in the aviation industry and many planes add artificial feel to give pilots feedback on the fly-by-wire systems.
So ya, a good driver feels as if his car has a "soul" just like a good pilot can feel his plane's "soul". There's no immortal soul in a car, no consciousness, but there is a whole lotta love.
It sounds like your assessment of the complexity of a vehicle is specifically tuned to mechanical features of cheap gasoline cars. I would suggest it might be more accurate to describe this as personality instead of soul.
Unsurprisingly electric vehicles, which do not have clutches or transmissions at all, or temperamental engines with inconsistent power curves, will exhibit little signal in the areas you have tuned yourself to perceive. This does not indicate anything about them in a universal way.
Your response indicates that you are perhaps incurious about the nuances of driving an EV. Since it sounds like you have invested a lot in sensing personality specifics of gasoline vehicles, this makes sense.
Perhaps early EV attempts were muted in their expression of activity personality. Entry level Teslas certainly are not fun to drive in the same way as an old Golf. Have you tried the Ioniq 5?
You extrapolated a lot about myself from an explanation of what constitutes a machine's personality.
For starters, I wouldn't call the Golf cheap. As to my "old" truck, if had 30k miles when I traded it in. I used "old" as in "previous". As to the Golf, it has <60k miles on it. As far as Im aware, EVs still have steering columns that loosen overtime.
EV do have their own characteristics, namely low end torque and insane amount of engine braking. They're also heavy hogs. I am not the poster who said EVs lack a "soul", I just explained what "soul" meant to someone who snickered at the idea of a machine having a "soul"; I introduced the idea that the "personality" is better suited and explained why.
I have no bias against heavy, torquey, rear wheel drive sedans - my first car was a crown vic, and I loved it for what it was.
As to my interest in EVs, you're right, I don't like them. I think they are unconscionably immoral in their impact on the environment (by taking precious batteries from hybrids that have a greater impact on CO2) and the labor (ie Congo) market.
But I am not a tech-dinosaur for in transportation. The manual tranny is long dead, having lost any advantage twenty years ago. I believe that hybrids should be highly promoted, no matter how insipid Toyotas are.
Infact, if I'm being completely honest, I dont even like cars. If much rather ride a motorcycle, and I believe that, for environmental reasons, the wider the vehicle the lower its speed limit should be. Cars should be limited to 40 mph by the factory. Trucks to 30, motorbikes 90 :D
Toyotas are boring. BMW and Honda (the cars too) were fun. Cars are expensive appliances, and most people are terrible drivers distracted by their phones.
Nah, when you've spent ten thousand hours doing something, you get a feel for it. It's not a sentient being, but it gains a feeling and a significance beyond what's printed on the window sticker. (I would argue that sentient beings don't have souls either. It's just a shorthand for a poorly-defined set of attributes and behaviors.)
A lot of people anthropomorphize machines, as it helps engage our built-in anticipation instincts to track when the machine will be "hungry" or "tired" without expending conscious thought. If the machine starts to sound or feel different, even in ways we can't put into words, that may surface as a sense of "attitude" or "unhappiness", and it may do so long before the difference would be dramatic enough to merit other mention. On-board diagnostics are great at identifying certain malfunctions in the engine and a few other systems, but driveline and suspension are still largely unmonitored except by ear, by feel, and by intuition. And there are still plenty of engine conditions that manifest as a gut feeling long before they set a DTC. Getting something checked out when it feels "off", versus waiting until it fails more obviously, may avert an unscheduled mishap in the middle of a cross-country roadtrip.
There are certainly lots of people who haven't spent that much time behind the wheel, or whose coming-of-age wasn't inextricably linked to the jingle of keys as a symbol of freedom and independence, or whose appreciation of rock and roll doesn't equate the growl of an electric guitar with the growl of an engine. Those people are to be forgiven for not seeing cars as having souls, but that lack of imagination on their part should not limit the imaginations, or the useful instincts, of the rest of us.
EVs have their own quirks and feelings, but there's not such a complicated web of air and temperature and chemistry and hydraulics and cable-stretch and dozens of individual bearings and mounts and linkages behind their behaviors. And they don't have a century of hot-rodding culture built up around them yet, no flames painted on the side, nor any combustion to inspire same. No exhaust notes to tune; if an EV's noises show up in music, it'll be more like Aphex Twin than Van Halen. Which is all well and good, but all of these things move EVs farther from any of the behaviors that we refer to with the shorthand of "soul".
Brakes tend to last much longer because the car uses the motor to brake. Some Tesla motors are oil-cooled, some are just air cooled and the reducer just uses grease[1] instead of oil. There are no piston rings, no blow-by, no sliding friction, no wear items, the temperature stays below 100 C, the pressure is always ambient, and the case is completely watertight. The oil/grease can last practically forever.
> I can bring 100L gasoline with me to add 1000 km range on top of existing 500 range.
Driving 12 hours at a time is unsafe and you should not do it. If you are regularly driving 1500 km into wasteland, an electric car is not for you. If you only do it a few times a year, I recommend renting.
> I can charge it within 5 minutes, not 5 hours.
Have you not heard? They can charge 200 miles in 15 minutes.
> It does not get worse with every year
It's a car. They absolutely get worse every year. Driving at high speed over bad roads takes a toll and all cars fall apart over time.
> Electric cars probably are the future, but I don't like this future. They don't have a soul.
Did televisions, before flatscreens replaced them? I don't think so. I think it was just the nostalgia for a time when it was new and important. But a car now is a conveyance. 99.99% cars have as much soul as an elevator- another thing that used to be special and personal.
If you want soul in the thing you drive to work, you always had to buy something special. You did not find it in a Honda Civic. If you want that, buy a motorcycle, or an E100 car. Those things will still exist even if EVs completely replace gasoline, because they just aren't the same thing.
You are not afraid of electric cars replacing racecars, or grand tours through the mountains or deserts or forest. You are sad about electric cars replacing 8 lanes of LA traffic, of I-98 being quiet, of less children with asthma. That's a silly thing to be sad about. The soul of driving is not going anywhere.
[1]: Because I NEVER tire of saying it: grease is amazing. It seems inefficient because it's thick like peanut butter, but it's the best. It's shear-thinning, so that as soon as it starts moving, it spreads into an incredibly thin low-viscosity layer that's just as frictionless as oil. Unlike oil, it never drips off, never needs pressure, always covers the surface. Contamination works itself out automatically (unlike in oil, where it's recirculated). It's chemically and thermally stable. Grease is the BEST.
The SSL cert on your website is probably expired (cloudflare is warning about it). I suggest you just use letsencrypt and auto renew with certbot, or whatever they use these days.
If designed well, this type of motor could do regenerative braking too. It's a matter of proper control of current in the stator and rotor and their phase difference, thus mostly electronics.
The innovation here is in the packaging, fitting the brushless inductive power coupling for the field excitation inside the shaft. T
he idea of using a high frequency rotating transformer or inductive coupler to transmit current to the field winding without using brushes and slip rings has been investigated by a number of companies, universities, and national labs.
A good survey paper of excitation systems for wound field synchronous machines or electrically excited synchronous machines is.
J. K. Nøland, S. Nuzzo, A. Tessarolo and E. F. Alves, "Excitation System Technologies for Wound-Field Synchronous Machines: Survey of Solutions and Evolving Trends," in IEEE Access, vol. 7, pp. 109699-109718, 2019, doi: 10.1109/ACCESS.2019.2933493.
An example of a high frequency transformer or inductive coupling developed by General Motors is detailed for example in the following paper.
C. Stancu, T. Ward, K. M. Rahman, R. Dawsey and P. Savagian, "Separately Excited Synchronous Motor With Rotary Transformer for Hybrid Vehicle Application," in IEEE Transactions on Industry Applications, vol. 54, no. 1, pp. 223-232, Jan.-Feb. 2018, doi: 10.1109/TIA.2017.2757019.
Below is some work done by Oak Ridge National Lab on rotating high frequency transformers for field excitation.
T. Raminosoa, R. H. Wiles and J. Wilkins, "Novel Rotary Transformer Topology With Improved Power Transfer Capability for High-Speed Applications," in IEEE Transactions on Industry Applications, vol. 56, no. 1, pp. 277-286, Jan.-Feb. 2020, doi: 10.1109/TIA.2019.2955050.
The field excitation current is typically provided using a single phase high frequency transformer (20 to 100 kHz switching frequency) which is then rectified by a rotating full bridge rectifier.
Just to clear up some of the misconceptions in the comments. In state-of-the-art electric vehicles there are basically three main machine topologies that are used for the main traction machine.
- Interior permanent magnet synchronous machines (IPMSMs): A large number of OEMs and suppliers use/supply this motor topology, e.g., General motors, Tesla model 3, Ford, etc.
- Induction machines (IMs): Also used by a large number of OEMs and suppliers, e.g., Tesla model S and X, G.M. for assist motors, etc.
- Wound field synchronous machines (WFSMs) [in Europe more commonly known as electrically excited synchronous machines (EESMs) but they are the same thing] - Currently used in Renault and some BMW models. A large number of suppliers are developing them.
Each of the machine topologies has tradeoffs compared to the others, cost, manufacturing CapEx, supply chain risk, drive cycle efficiency, difficulty of control, failure modes, cooling complexity, etc.
WFSMs or EESMs have some potential advantages over IPMSMs or IMs for some applications.
- They don't contain rare earth permanent magnets eliminating the supply chain and price volatility associated with them.
- In terms of drive cycle efficiency generally they are more efficient than IMs and if the drive cycle is dominated by moderate torques and highspeeds they can exceed the drive cycle efficiencies of IPMSMs.
- They are very easy to field weaken and theoretically can have an infinite constant power speed range.
- The field excitation can be controlled to provide unity power factor potentially allowing the stator inverter to be downsized.
The main negatives of WFSMs or EESMs compared to IPMSMs or IMs are:
- The field excitation is more complicated and requires power electronics either for brushes and slip rings or inductive power transfer approaches.
- The cooling of the field winding is difficult and typically spray/jet cooling of the end turns or at a minimum through shaft cooling.
- The control of WFSMs or EESMs is considerably more complicated than IPMSMs or IMs.
This is not new, if you have a car with any fossil fuel motor, you likely already have a similar device: your alternator. By applying a voltage between 2 and 13 to the exciter coil, you can adjust how much is drawn from the primary winding.
A car alternator uses brushes or slip rings to get power to the excitation coils, which is a big part of what the motor in the article has been designed not to use.
It seems like the big innovation here is that it doesn't use slip rings and brushes anymore, and the power to the rotor is now transferred via induction coils:
"energy is transferred inductively, i.e. without mechanical contact, into the rotor, generating a magnetic field by means of coils. Thus, the I2SM does not require any brush elements or slip rings. Furthermore, there is no longer any need to keep this area dry by means of seals. As with permanently magnetized synchronous motor, the rotor is efficiently cooled by circulating oil."
The good part is there's no more brushes to wear out and no dry seal needed so the motor can now be oil cooled from the inside as well, but to me it raises the big question about the power losses incurred by the energy that's transferred to the rotor via induction versus the previous direct contact via brushes and slip rings.
Those coils seem to be quite far apart from one another, have a look at this moment in their video: https://press.zf.com/press/en/media/media_60352.html?kaltura...