Very cool. Good to see more axial flux motors in the wild - will be interesting to see if they become the new standard in future. With smaller material costs the cost to manufacture at scale could actually become lower than radial
I expect radial will still dominate for at least another decade or so outside of premium performance focused cars. Radial has been battle-tested and proven. Axial still has a few more years to prove it's reliability in the field. Higher loads and stresses, tighter tolerances could make the axial motors less reliable overall especially at mass market trims. Mercedes is probably over-engineering for reliability and performance on the premium car
Radial is also "good enough" for most applications. The efficiency, form factor and weight improvements of axial is nice, but they aren't the limiting factor. Radial is already highly efficient, reasonably light and small. The real level for weight is the battery
AndrewDucker 3 hours ago [-]
It would have been awesome if that article had, at any point, explained what an electric axial flux motor was, and why anyone might want one.
chinathrow 3 hours ago [-]
Click "More" and scroll down:
"In contrast to conventional radial flux motors, the electromagnetic flux in an axial flux motor runs parallel to the axis of rotation. The key components are arranged in a disc‑shaped layout: two rotors sandwich the stator from the left and right. This design enables an especially compact motor architecture, high power and torque density, and new freedoms in drivetrain packaging. In the new Mercedes‑AMG GT 4‑Door Coupe, the motor at the front axle is just under nine centimetres wide; the two motors at the rear axle each measure around eight centimetres in width. The three axial flux motors are integrated per axle into so‑called High Performance Electric Drive Units (HP.EDU), where they are combined with a compact input planetary gearbox in a single housing."
giancarlostoro 44 minutes ago [-]
Really the kind of thing that should be earlier in an article about… that very thing the reader is wondering about, but maybe we arent the target audience?
swiftcoder 1 hours ago [-]
This is the same design that enables the PCB Stator Motors, right?
lsowen 2 hours ago [-]
A very good YouTube video from Munroe Live (an engineering firm specializing in "design for manufacturing") explaining it: https://youtu.be/dCO633KE7RA "Axial Flux Motors Explained"
Visited Astrall Dynamics, a Chinese startup that builds quadrupeds with axial flux motors here in Shenzhen. Super cool to see the robots in actions, carrying 60kg of weight up over 20 flights of stairs quite rapidly. The high torque at the compact form factor was super impressive. As far as I understood they are more complex to manufacture, especially at scale.
kenanfyi 3 hours ago [-]
“What“ might be a long answer, but why anyone might want one is to have increased torque density for the given volume and diameter. So they are thin motors where the generated flux is parallel to the shaft. And they are like the standard PMSMs where you apply the same driving algorithm from the inverter side to use them.
altairprime 20 minutes ago [-]
Consider the thousand or so comments at https://hn.algolia.com/?q=axial for more details. While it’s no substitute for a well-written comprehensive article, it certainly is a smorgasbord of answers.
jorams 3 hours ago [-]
It's a bit buried, but it does:
> In contrast to conventional radial flux motors, the electromagnetic flux in an axial flux motor runs parallel to the axis of rotation. The key components are arranged in a disc‑shaped layout: two rotors sandwich the stator from the left and right. This design enables an especially compact motor architecture, high power and torque density, and new freedoms in drivetrain packaging. In the new Mercedes‑AMG GT 4‑Door Coupe, the motor at the front axle is just under nine centimetres wide; the two motors at the rear axle each measure around eight centimetres in width. The three axial flux motors are integrated per axle into so‑called High Performance Electric Drive Units (HP.EDU), where they are combined with a compact input planetary gearbox in a single housing.
creativeSlumber 3 hours ago [-]
> The three axial flux motors are integrated per axle
I wonder why they need tree motors per axle.
roelschroeven 2 hours ago [-]
It's poorly worded. There aren't three motors per axle, there are three motors total: one on the front axle and two on the rear axle.
manarth 2 hours ago [-]
The translation's a little woolly.
For the AMG GT4 there will be 3 motors: two at the rear, and one at the front.
My interpretation (and my German's pretty lousy) is that each motor is combined with a gear system in a single package, and they're calling the overall package (motor plus gears) a High Performance Electric Drive Unit (HP.EDU).
The two rear motors will probably be independent, so no need for a mechanical rear diff (it'll be electronically controlled).
There's no mention of a front diff, so it's unknown whether that's built into the front HP.EDU or is a separate mechanical diff).
DFHippie 2 hours ago [-]
I got the impression that there were three motors altogether and they were integrated with the axles.
PxldLtd 1 hours ago [-]
Here's a great Instructable on building one yourself, much better explanations in there.
Then all you need is a good recording and decent headphones
bayindirh 28 minutes ago [-]
A good recording and a sound system which can move the exact amount of air that the engine has moved, to be precise.
aduty 2 hours ago [-]
Since they're relatively compact they will probably start stacking them. Like pancakes.
WJW 2 hours ago [-]
Stick two of them together on the same axle then.
numpad0 2 hours ago [-]
Most motors have N-S axis of magnets aligned tangential to the axis of rotation. Axial flux motors have N-S poles parallel to rotation. This allows motors to be thinner and wider as well as anyhow more lighter and sometimes easier made. Whether they make sense depends, it seems.
stasomatic 1 hours ago [-]
This sounds straight out of an 89’s sci-fi flick. What time we get to live in!
The AI voice is annoying, the content is as personal a a vanilla yogurt but the animation is clear.
LoganDark 2 hours ago [-]
I would be careful about that video, it seems relatively "explaining this new amazing innovation that has no/negligible downsides (please invest in us)" rather than "explaining the practical pros & cons of this technology".
Thanks for posting this. Axial flux motors aren't some new sci-fi invention. We've had them in gadgets for a long time like in the floppy drive example. This is just one of the first industrial scale implementations of high-torque applications.
As far as I understand it's so small and lightweight you can put one on each wheel and remove brakes and still save weight (something something unsprung weight bad).
verminator468 58 minutes ago [-]
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kenanfyi 3 hours ago [-]
I remember when YASA announced it and when MB bought them. Amazing technology and advancement in electric motor design. Good to see they somehow try to commercialize it.
latentframe 39 minutes ago [-]
An interesting part here is probably manufacturing and not the motor itself : going from a prototype to something you can mass produce reliably is often the hard part
Urahandystar 2 hours ago [-]
Glad YASA's achievements are being realised but the UK really needs to get it act together so we can fully realise the next tech breakthough.
krn1p4n1c 43 minutes ago [-]
I would guess that hydro and other generator forms would benefit from this design as well?
Personally I’d love to see this make it’s way into power tools and CNC motors.
aetherspawn 30 minutes ago [-]
Probably not. A huge disadvantage of axial flux motors is they have a large number of poles, which means that they get less efficient at high speed because they require say 5x as much switching.
This makes them kind of unsuitable for power generation and really high power motors (despite their power density) where the main way you get more power is just to spin really fast.
The other disadvantage is they have such a low amount of material in them, that the stator overheats really easily. And the topology of the motor makes it really difficult to get the heat out efficiently, which again limits their maximum power.
Waterluvian 16 minutes ago [-]
That is one angry looking car.
ianpurton 2 hours ago [-]
The main benefit here seems to be smaller and lighter for the same power output.
jansan 1 hours ago [-]
Four years ago, when YASA's invention was discussed on HN, it attracted very little interest. Mercedes apparently saw more potential and decided to invest.
Tangential, how much regen can this system support?
For example, can a car with 200kW propulsion have a 400kW regen (Tesla has upto 65) and are cost effective like friction brakes?
masklinn 1 hours ago [-]
> can a car with 200kW propulsion have a 400kW regen
At the motor level it should be the same, in propulsion you’re converting current to torque and in regen you’re converting torque to current, with the same hardware. The high voltage wiring is the same and will set the same limit on current regardless of direction.
I believe bidirectional inverters are generally symmetrical as well, so that should not be a factor.
Which I reckon leaves two factors:
1. Battery C rates, afaik pretty much all chemistries have a higher discharge rate than charge rate, especially when trying to maintain them for a long time, so by that account regen power would at most be the same as propulsion (if the entire power train is sized for the battery’s charging rate).
2. Artificial limitations, obviously you could always artificially under-prop, though that seems unlikely outside of niche applications.
tldr: I don’t think so, except on a technicality (that you can artificially hobble propulsion).
wjnc 2 hours ago [-]
Am I reading you right that breaking power (that you want to regenerate in the system) >> speeding power? Obvious now I come to think of it, and still pretty nifty new thing learned if true!
rdksu 2 hours ago [-]
Only if they could mass produce flux capacitor.
wizardforhire 2 hours ago [-]
This is gonna be wild in a few years when these things are parted out the way tesla motors have been…
Everything about these is crazy!
Ah, another fantastic British innovator (YASA) having to realize its potential (and ultimately the downstream economic benefits of commercialisation) abroad.
Brought to you by the only country to have a space programme and abandon it.
fancyfredbot 21 minutes ago [-]
Britain didn't abandon it's space programme. It abandoned a launch rocket programme though. That was over 50 years ago and the rocket was less capable and more expensive than alternatives at the time.
globular-toast 3 hours ago [-]
Did they have to? My impression is British companies sell out as soon as they can these days. Is this something that could be changed with policy? Does Germany incentivise running companies more? Or is this cultural, e.g. British people are more risk averse?
herodoturtle 3 hours ago [-]
I suspect it has more to do with Germany’s industrial scale in the automotive space (as opposed to incentives or culture).
ahartmetz 1 hours ago [-]
Yeah. Traditional car makers have enormous demand for EV innovations. Germany has more and bigger traditional car makers.
Urahandystar 2 hours ago [-]
It's very difficult to raise late stage capital in the UK, especially for deep tech. We invent so much but our capital ecosystem is all tied up in land and our pensions providers don't want to know.
mytailorisrich 2 hours ago [-]
The UK is by far the best country to raise venture capital in Europe, and is the third largest market in the world after the US and China...
JumpCrisscross 2 hours ago [-]
> UK is by far the best country to raise venture capital in Europe
For late stage? Continental Europe has its banks and industrial policy. America and China have their deep pockets. Scaling out of the UK is incredibly hard, doubly so post Brexit, that’s why they sell early.
mytailorisrich 2 minutes ago [-]
I think continental Europe has nothing on the UK when it comes to banks and financial markets. The UK has the deepest pockets in Europe because it is a hub for global capital. Brexit does not seem to have made a difference:
"Most late-stage capital comes from the US and UK."
joe_mamba 1 hours ago [-]
>Continental Europe has its banks
UK has City of London that dwarfs the banks of continental Europe. we're talking big banks, Fintech, HFT, etc. When you deal with Austrian banks you realize they're 10-20 years behind the UK.
> and industrial policy
Continental Europe has a large but somewhat inefficient(compared to Asia) and heavily subsidized industrial policy, acting more a a jobs program for politicians chasing votes and state subsidies, that the UK gave up on during Thatcher(for better and worse), and stayed in the niche, low volume but highly important aerospace and defense parts that dwarfs that of continental Europe.
Ofc that also means the labor market in UK is very K-shaped. Highly paid skilled niche jobs in London and the university research centers, and then a wasteland everywhere else.
jemmyw 3 hours ago [-]
I think Germany has tax rules that make exits harder, whereas it's very easy in the UK to sell. If you have a more free market next to protective ones it makes sense that your IP is going to flow in that direction.
throwaway132448 26 minutes ago [-]
It’s cultural. It is not difficult to raise a lot of money in the UK. The problem is that the UK (government, investors, employees and employers) got so high on the margins of services and finance in the 90s, that it has never recovered from this all-consuming addiction. Everything else simply attracts no interest comparatively, economic diversification be damned.
3 hours ago [-]
jackson281 2 hours ago [-]
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eptcyka 3 hours ago [-]
Never become dependent on doing hideously complicated things. You will eventually struggle to choose to do something more efficient, as the european auto industry is currently displaying. The car where thid motor will be used will, given current market sentiment, be a massive flop. Here they are showing off how complex the manufacturing process is. Surely we’d all be better off with simpler and cheaper processes.
Ye, and I’d wager China will put that motor into affordable vehicles first, not some BS AMG GT 4 door/4 seat hyper car.
epolanski 2 hours ago [-]
Mercedes always brings their latest technologies to the highest tier of cars first. Almost every major innovation has first debuted on the S class
rcxdude 50 minutes ago [-]
Efficiency and cost savings at scale usually involve an increase in complexity: in mass manufacturing, complexity is generally a fixed cost and so can be amortized over larger volumes.
citrin_ru 2 hours ago [-]
A typical modern car is already hideously complicated and a different type of motor would not change this.
What is the current market sentiment? Share of EVs is slowly rising so having a good motor as important as ever.
IshKebab 2 hours ago [-]
He says, typing on one of the most hideously complicated things humanity has created.
vrganj 2 hours ago [-]
By that logic we should all just be writing assembly manually. Screw hideously complicated higher level languages. Screw LLMs in particular, so complicated!
epolanski 2 hours ago [-]
> Never become dependent on doing hideously complicated things
Is Mercedes stupid?
How did Carl Benz dare to do something as hideously complicated as building the first gasoline-powered car in history?
And why did they kept inventing complicated stuff that ended in all modern cars like ABS, adaptive cruise control, direct fuel injection, emergency brake assist, etc, etc?
eptcyka 2 hours ago [-]
Not all of those inventions are bad. But not all of them are coming from a place of necessity. All of them do increase complexity. My gripe with Mercedes is not that they are constantly pushing boundaries on what can be done with more tech. My main gripe is that the EVs they are building are essentially as complex as the ICE cars and follow largely the same design principles as the ICE cars. For instance, in the EQS, instead of applying engine breaking when the driver takes their foot off the pedal, they went to great lengths to _move the break pedal_ in proportion to the amount of engine breaking that is currently being applied as per the VCUs command. And yet the door cards on the EQS are not up to the standard of an S class.
My main gripe with MB is that they have this new technology that could simplify things and let them build a better product. Instead of building around it, they shove it in to their existing designs. I was expecting an electric S class to be more akin to a Lucid Air sans the teething problems of a new company. Instead, we get weak attempts at solving non issues.
And whilst they are certainly not in the market of producing affordable vehicles, I would hope that using EV tech they could create a better version of their existing fleet. I do not think anyone buying an A class cares about the 4 popper under the hood - losing it and simplifying radically, in my mind at least, would give them more budget and leeway to create a more compelling product.
manarth 2 hours ago [-]
> "instead of applying engine breaking when the driver takes their foot off the pedal, they went to great lengths to _move the break pedal_ in proportion to the amount of engine breaking that is currently being applied as per the VCUs command"
Regenerative braking slows the car more aggressively than an ICE where you take your foot of the gas, so the pedal change isn't putting on the brakes, it's communicating to a driver used to ICE that the car is slowing more than might be expected.
There may also be a sports-related reason for people who habitually left-foot brake.
petre 1 hours ago [-]
It depends how much you draw from the motor/generator. One can modulate it as they want, whatever can't go into the battery due to chemistry or drive constraints can be disposed of as heat.
eptcyka 1 hours ago [-]
You clearly have never used a car like that. You develop muscle memory for where the pedal is - finding that the pedal is not where it used to be does not inspire much confidence.
Every other manufacturer has managed to control regen breaking via throttle modulation - even ICE hybrid cars have been doing that for ages.
manarth 36 minutes ago [-]
I've used left-foot-braking in my (ICE-powered) daily driver for years.
Regenerative braking is very different to taking your foot off the accelerator in a conventional ICE car, it's much more powerful a stopping force than traditional engine-braking.
I understand the rationale for moving the pedal to illustrate the amount of "braking" force. I'll admit I'm not exactly a typical driver though.
flohofwoe 2 hours ago [-]
The equilibrium of "good enough vs technological simplicity" for cars was probably reached in the 1950s. Everything after that was more or less solving "non-issues" with ever-increasing complexity ;)
KingOfCoders 2 hours ago [-]
And why had that cars be to be refueled in pharmacies?
I expect radial will still dominate for at least another decade or so outside of premium performance focused cars. Radial has been battle-tested and proven. Axial still has a few more years to prove it's reliability in the field. Higher loads and stresses, tighter tolerances could make the axial motors less reliable overall especially at mass market trims. Mercedes is probably over-engineering for reliability and performance on the premium car
Radial is also "good enough" for most applications. The efficiency, form factor and weight improvements of axial is nice, but they aren't the limiting factor. Radial is already highly efficient, reasonably light and small. The real level for weight is the battery
"In contrast to conventional radial flux motors, the electromagnetic flux in an axial flux motor runs parallel to the axis of rotation. The key components are arranged in a disc‑shaped layout: two rotors sandwich the stator from the left and right. This design enables an especially compact motor architecture, high power and torque density, and new freedoms in drivetrain packaging. In the new Mercedes‑AMG GT 4‑Door Coupe, the motor at the front axle is just under nine centimetres wide; the two motors at the rear axle each measure around eight centimetres in width. The three axial flux motors are integrated per axle into so‑called High Performance Electric Drive Units (HP.EDU), where they are combined with a compact input planetary gearbox in a single housing."
Edit: a video from them on this particular YASA tech being discussed : https://youtu.be/m507ryWhc6c
> In contrast to conventional radial flux motors, the electromagnetic flux in an axial flux motor runs parallel to the axis of rotation. The key components are arranged in a disc‑shaped layout: two rotors sandwich the stator from the left and right. This design enables an especially compact motor architecture, high power and torque density, and new freedoms in drivetrain packaging. In the new Mercedes‑AMG GT 4‑Door Coupe, the motor at the front axle is just under nine centimetres wide; the two motors at the rear axle each measure around eight centimetres in width. The three axial flux motors are integrated per axle into so‑called High Performance Electric Drive Units (HP.EDU), where they are combined with a compact input planetary gearbox in a single housing.
I wonder why they need tree motors per axle.
For the AMG GT4 there will be 3 motors: two at the rear, and one at the front.
My interpretation (and my German's pretty lousy) is that each motor is combined with a gear system in a single package, and they're calling the overall package (motor plus gears) a High Performance Electric Drive Unit (HP.EDU).
The two rear motors will probably be independent, so no need for a mechanical rear diff (it'll be electronically controlled).
There's no mention of a front diff, so it's unknown whether that's built into the front HP.EDU or is a separate mechanical diff).
https://www.instructables.com/Designing-and-Building-an-Axia...
https://en.wikipedia.org/wiki/British_Racing_Motors_V16
Personally I’d love to see this make it’s way into power tools and CNC motors.
This makes them kind of unsuitable for power generation and really high power motors (despite their power density) where the main way you get more power is just to spin really fast.
The other disadvantage is they have such a low amount of material in them, that the stator overheats really easily. And the topology of the motor makes it really difficult to get the heat out efficiently, which again limits their maximum power.
https://news.ycombinator.com/item?id=31701133 Inside Yasa: how a British firm is revolutionising electric cars (2 points | 0 comments)
For example, can a car with 200kW propulsion have a 400kW regen (Tesla has upto 65) and are cost effective like friction brakes?
At the motor level it should be the same, in propulsion you’re converting current to torque and in regen you’re converting torque to current, with the same hardware. The high voltage wiring is the same and will set the same limit on current regardless of direction.
I believe bidirectional inverters are generally symmetrical as well, so that should not be a factor.
Which I reckon leaves two factors:
1. Battery C rates, afaik pretty much all chemistries have a higher discharge rate than charge rate, especially when trying to maintain them for a long time, so by that account regen power would at most be the same as propulsion (if the entire power train is sized for the battery’s charging rate).
2. Artificial limitations, obviously you could always artificially under-prop, though that seems unlikely outside of niche applications.
tldr: I don’t think so, except on a technicality (that you can artificially hobble propulsion).
If you’re not caught up https://youtu.be/m507ryWhc6c?si=Hq3dfjXYxEIlYzeo
Brought to you by the only country to have a space programme and abandon it.
For late stage? Continental Europe has its banks and industrial policy. America and China have their deep pockets. Scaling out of the UK is incredibly hard, doubly so post Brexit, that’s why they sell early.
https://www.uktech.news/funding/late-stage-funding-surges-as...
Regarding AI (since that's the hot thing of the day), but IMO indicator of where the money is:
https://digital-strategy.ec.europa.eu/en/library/funding-ai-...
"Most late-stage capital comes from the US and UK."
UK has City of London that dwarfs the banks of continental Europe. we're talking big banks, Fintech, HFT, etc. When you deal with Austrian banks you realize they're 10-20 years behind the UK.
> and industrial policy
Continental Europe has a large but somewhat inefficient(compared to Asia) and heavily subsidized industrial policy, acting more a a jobs program for politicians chasing votes and state subsidies, that the UK gave up on during Thatcher(for better and worse), and stayed in the niche, low volume but highly important aerospace and defense parts that dwarfs that of continental Europe.
Ofc that also means the labor market in UK is very K-shaped. Highly paid skilled niche jobs in London and the university research centers, and then a wasteland everywhere else.
What is the current market sentiment? Share of EVs is slowly rising so having a good motor as important as ever.
Is Mercedes stupid?
How did Carl Benz dare to do something as hideously complicated as building the first gasoline-powered car in history?
And why did they kept inventing complicated stuff that ended in all modern cars like ABS, adaptive cruise control, direct fuel injection, emergency brake assist, etc, etc?
My main gripe with MB is that they have this new technology that could simplify things and let them build a better product. Instead of building around it, they shove it in to their existing designs. I was expecting an electric S class to be more akin to a Lucid Air sans the teething problems of a new company. Instead, we get weak attempts at solving non issues.
And whilst they are certainly not in the market of producing affordable vehicles, I would hope that using EV tech they could create a better version of their existing fleet. I do not think anyone buying an A class cares about the 4 popper under the hood - losing it and simplifying radically, in my mind at least, would give them more budget and leeway to create a more compelling product.
There may also be a sports-related reason for people who habitually left-foot brake.
Every other manufacturer has managed to control regen breaking via throttle modulation - even ICE hybrid cars have been doing that for ages.
Regenerative braking is very different to taking your foot off the accelerator in a conventional ICE car, it's much more powerful a stopping force than traditional engine-braking.
I understand the rationale for moving the pedal to illustrate the amount of "braking" force. I'll admit I'm not exactly a typical driver though.
https://de.wikipedia.org/wiki/Datei:Wiesloch_Stadtapotheke_E...