Protean has a production ready hub motor for cars

[zappy]

Let's see, what other configurations might be at least some fun with a 100hp hub?

le jamias contente (the Never satisfied) is overdue for a hub motor technology upgrade. it is a 114 years old, the first car to break 100km/h speed record and it was an EV!
I would much prefer to drive around in le jamias contente , than that over stylized rubbish red "AERO".
le jamias contente has a wind in the hair, Whylie Coyote sitting on the acme rocket look i prefer and probably similar drag to the AERO.


Although lots of unsuspended weight is not ideal, our hub motor bikes rear wheel weighs over 10kg on a 40kg machine or 25%, But to be fair its more like 10kg of unsuspended weight on the rear out of a total of 130kg all up weight and 9" of travel. Motorcross bikes have similar ratios but 12" of travel and they go on some of the bumpiest roads imaginable. So unsuspended weight is not ideal but is an often over stated performance hit, especially in regards to shopping trolley type cars operating on smooth suburban type roads with only 4.5" of suspension travel, full droop to full bump. The ford F series is the biggest selling vehicle, in the worlds largest market for over 30 years! and its stupid(virtually unchanged) live rear end would weigh more than these up scaled bike hub motors. Nascar also uses same junk etc.
Like our bikes cars real estate area is at a premium. Imagine the new design flexibility with no need for an engine bay and radiator grill.(radiators have a drag coefficient of around 1.0 or equivalent to a house brick). I'm not saying hub motors are the ultimate electrically(they have to be bigger than an equivalent high revving geared motor) but it does mean vehicle manufactures can mass produce hub motor corners and bolt them to any body shape.
dg said

It also requires running power cable out along the suspension arms where they are exposed and easily damaged. This design seems to create more problems than it solves.

We already run abs wires, high pressure hydraulic brake lines etc. and drive shafts. Running some cables is a lot simpler/lighter than running mechanical joints that need to transmit lets see, standard car 300Nm motor, 3:1 1st gear reduction, 4:1 diff gear equals 3600Nm! That has to be heavy/expensive.
Just some thoughts.
Zappy

 

[liveforphysics]

I see lots of problems with hub motors in cars. The unsprung weight will hurt ride in addition to handling. I don't see that saving a couple halfshafts is really worth bothering with. And why put the controller in high heat high vibration environment? It also requires running power cable out along the suspension arms where they are exposed and easily damaged. This design seems to create more problems than it solves.

I used to think that as well, but after a few years of looking at where the losses come from in an electric drivetrain system, I can respect somebody making the added unsprung weight trade-off to try to achieve the ultimate in low-losses direct drive system. No gearing or power transfer losses, big simple low RPM electric motor turning relatively slowly can be extremely efficient if designed properly for the application.

Also, let's not forget that just because it would wreck the handling of a CRX or Elise etc, doesn't mean it would even need to weight more than the existing gawdy huge heavy 20" wheels and tires people put on luxury cars and non-performance stuff. Not saying there aren't performance light rims offered in 20" sizes, just saying people have been adding ~25lbs a wheel to otherwise stock lowered cars for about the last decade or so and typically say they like the handling of the car better afterwards. As a guy who road races a bicycle with an entirely unsprung rear-end at >100mph, I can tell you unsprung weight isn't as ideal as sprung mass, but it's not quite as much of a deal breaker as most folks would think.

 

[-dg]

Perhaps. Of course most of those 22" rims are getting added to truckish things which already have high unsprung weight and which are already pretty compromised for handling. But in a sensible car, eg Honda Accord or smaller, most of the OEM designs have fairly low unsprung weight and I suspect that an extra 70 lbs would be detrimental.

I agree the simplicity is appealing but I think that CV joints are pretty low loss. I also wonder in accident if the wheel is torn off or something impinges into the wheel well about electrical safety, it the potential for shocks, sparks etc. It is would be much easier to protect the cabling with a pair of center mounted back to back motors directly driving a half shaft. This would still have the same direct drive motor load and speed properties as a hub motor..

 

[The Stig]

All-Electric Ford Fiesta With Rear-Wheel Drive

all-electric, rear-wheel drive vehicle using wheel hub motors

The project was designed in close cooperation with Ford, though it isn’t an official Blue Oval project, but rather the brainchild of Germany-based Schaeffler.

Looks like some pro's may produce some hub motor cars

Perhaps. Of course most of those 22" rims are getting added to truckish things which already have high unsprung weight and which are already pretty compromised for handling. But in a sensible car, eg Honda Accord or smaller, most of the OEM designs have fairly low unsprung weight and I suspect that an extra 70 lbs would be detrimental.

The honda accord is a fully highway capable sedan. By low-performance we mean city cars. Like compact cars or like any of the non-luxury EV's of today. Except a Hub motor car might actually be quite a lot more affordable because the manufacturer saves loads of money from avoiding designing and building and custom controller+motor+u-joints+halfshafts+suspension arms to accomodate/the entire rear disk brake system. Instead you just stick a hub motor on which is cheap because they can be built in masses and adapted to many different platforms. Plus you get even more space in the car. You get a compact car with a the space of a station waggon. It would be o.k. on the highway... but as Luke said it would be a good deal, I'd say especially for a city car like a fiesta or smart like current basic EVs which have shown there is a market.

I also wonder in an accident if the wheel is torn off or something impinges into the wheel well about electrical safety, it the potential for shocks, sparks etc.

Realistically I can imagine they would be quite safe with electrical cut-off and safety features. You may be able to think of a failure mode that would result in an injury or death I dunno but it would probably be an unlikely one

 

[Punx0r]

Exactly.

Hubmotors would potentially allow a car manufacturer to offer an electric version of an existing model at a low cost (which it would need to be, as sales will inevitably be low).

The body shell could remain almost unchanged, save perhaps for a few holes to run cables, or mounting brackets for the electrics. These additions could be made by hand to standard shells by pulling them from the line before they go into the paint shop, then put them back on line. I believe this has been done for decades on limited edition/high performance special models of popular cars. It's hugely expensive to make changes to the bodyshell and converting a FWD car to RWD electric (with inboard motor(s)) would mean that.

With hubmotors you just need to change the suspension, nice and easy bolt-on stuff. Easily redesigned, manufactured and assembled. Similar story with replacing the ICE with a battery - just repurpose existing mounting points.

 

[The Stig]

Heres something we could get with hub motor city cars. Wheels that can turn 90 degrees for sideways parking!

Watch from 1:03

[youtube]yfs5z0Lg1Xc[/youtube]

 

[Hillhater]

Exactly.

Hubmotors would potentially allow a car manufacturer to offer an electric version of an existing model at a low cost (which it would need to be, as sales will inevitably be low).
....With hubmotors you just need to change the suspension, nice and easy bolt-on stuff. Easily redesigned, manufactured and assembled. Similar story with replacing the ICE with a battery - just repurpose existing mounting points.

Since the majority of "city" car likely candidates for EV conversion are already FWD, why change that to RWD ?
It seems to me to be much simpler & cost effective to pull the ICE & Gbox, then hook up the drive motors(s) direct to the drive shafts leaving all the existing suspension , brakes, hubs , etc as stock.
All other things being equal, ( brakes, wheel , tyre etc) a hub motor must add 20+ Kg ( Protean is 31kg !) to each wheel. Now its not just "handling" that suffers, but imagine that extra 20+kg hitting a pot hole, or a rock at 100km/hr ! . the extra impact on the tyre & wheel is enormous and damage much more frequent....to say nothing of the rough ride !

 

[-dg]

Since the majority of "city" car likely candidates for EV conversion are already FWD, why change that to RWD ?
It seems to me to be much simpler & cost effective to pull the ICE & Gbox, then hook up the drive motors(s) direct to the drive shafts leaving all the existing suspension , brakes, hubs , etc as stock.
All other things being equal, ( brakes, wheel , tyre etc) a hub motor must add 20+ Kg ( Protean is 31kg !) to each wheel. Now its not just "handling" that suffers, but imagine that extra 20+kg hitting a pot hole, or a rock at 100km/hr ! . the extra impact on the tyre & wheel is enormous and damage much more frequent....to say nothing of the rough ride !

Earlier the point was made that half-shafts and CV joints were expensive. Not really. Honda Civic half-shafts including both CV joints seem to be available online for well under $100. I assume factory cost can't really be much more. I doubt even diffs are that expensive. And once the motor is fixed to the chassis it can be hooked up to forced air or water for cooling. Since heat removal is the main limit on power for electric motors this allows a smaller lighter cheaper motor than a pair of passively cooled hub motors.

 

[Hillhater]

But if you go with a single motor, then you need a diff with its consequent cost, weight, space, and losses. !
Ultimately, that may all be offset by the cost, weight, efficiency etc etc gains from using a single motor, but that is unknown speculation until detail design is done.
I was simply proposing alternative location of these low rpm "Hub" motors whilst still avoiding power train losses or modifications to suspension and brakes.
I dont think a vehicle chassis designed for FWD , should be randomly switched to RWD...that is a big call.
..and i doubt there are many professional chassis engineers who relish the thought of a lot of unsprung weight in the wheel hubs.

 

[The Stig]

The battery will require a pretty complete chassis redesign anyway so the hub motor is just a much smaller and easier package to incorporate into that new design. As we've said the unsprung weight would be noticeable on the highway... but under 70 Km/h most non-techincal mainstream users won't notice. It could be a bigger hit outside the US where there is less highway driving.

 

[Chalo]

[...]once the motor is fixed to the chassis it can be hooked up to forced air or water for cooling. Since heat removal is the main limit on power for electric motors this allows a smaller lighter cheaper motor than a pair of passively cooled hub motors.

Sustained power output is not the measure of what is practical for transportation. Enough is enough; too much causes problems.

Extreme power to weight is also not a measure of practicality, since it implies a system that is not fault tolerant and will burn itself up if something goes wrong. Eliminating forced cooling means one less critical system to fail. And what is lighter or cheaper about adding an entire mechanical system over what would otherwise be necessary?

 

[Hillhater]

The battery will require a pretty complete chassis redesign anyway ....

I thought we were suggesting low cost "conversion" of existing designs ?
I would have thought the empty ICE engine bay would be the logical place for a custom shaped pack !

 

[The Stig]

Maybe for a DIY garage conversion. But I was referring to what car manufacturers might produce, and I don't think a manufacturer would put all that weight up front and up high where the ICE engine normally sits just above the frame, non of the modern EVs have been produced like that... Ideally it would be in the floor like where the Model S has it or on the floor and centered like where the volt has it. I think the chevy spark has it more towards the back... not sure why they did that but that would work better for a RWD hub motor car, having more weight on the drive wheels.

 

[Hillhater]

.. not sure why they did that but that would work better for a RWD hub motor car, having more weight on the drive wheels.

There are sound reasons why most modern passenger cars have gone to FWD, safe handling being one of the main considerations.
Weight distribution, and use of space are others.
These hub motors are proposed as an easy way for manufacturers to convert existing designs, if you have to re-engineer the chassis, you are designing a whole new product.

 

[Samd]

Thats a real shame about that canadian innovation.

I'm being a bit cheeky here. But it's the point that matters. You guys haven't struck hub motors on cars before? Imagine if Ferdinand Porsche Snr hadn't bothered with petrol engines 113 years ago.
What would be the state of vehicles today?

http://www.autoconcept-reviews.com/cars_reviews/porsche/lohner-%20porsche-electric-motor-in%20wheel-1900/cars_reviews-lohner-porsche-electric-motor-in%20wheel-1900.html

Excerpt:
When the World Exhibition in Paris opened to the public on April 14th 1900, car enthusiasts found that the outstanding new invention was an electric vehicle - the Lohner-Porsche. Its front wheels were driven by what were known as wheel hub motors, which Ferdinand Porsche - who was 25 years old at the time - had developed as head engineer of the car company "k.u.k. Hofwagenfabrik Jakob Lohner & Co." in Vienna-Florisdorf. Porsche as a Company will only appear 47 years later but the electric hub wheel drive invented by Professor Ferdinand Porsche - the future founder of Porsche Company - will be applied in several occasions like for the NASA Lunar Roving Vehicle of the Apollo Missions on the Moon and even today in some electric cars projects.

 

[The Stig]

.. not sure why they did that but that would work better for a RWD hub motor car, having more weight on the drive wheels.

There are sound reasons why most modern passenger cars have gone to FWD...

I dunno, I would think the main reasons for FWD would be because the ICE engine is in the front. Then by going with FWD you save space, you save on drive shafts, and you have more weight on the drive wheels. Maybe handling a bit too for accelerating out of corners

I'm not aware of any big problems with RWD, high end cars are made that way... BMW merc Ferrari etc...


Samd, that quite a revelation!

 

[Hillhater]

.. not sure why they did that but that would work better for a RWD hub motor car, having more weight on the drive wheels.

There are sound reasons why most modern passenger cars have gone to FWD...

I dunno, I would think the main reasons for FWD would be because the ICE engine is in the front. Then by going with FWD you save space, you save on drive shafts, and you have more weight on the drive wheels. Maybe handling a bit too for accelerating out of corners

I'm not aware of any big problems with RWD, high end cars are made that way... BMW merc Ferrari etc...
!

Well they could design cars with the engine in the rear.. like Porche 911, VW Beetle etc.. but why do you think they tend to avoid that these days ?? ..( think:..Corvair ?)
Its accepted now that FWD and front engine ( forward weight distribution) gives the safest handling characteristics (IE:understeer) for the "average" driver.

 

[The Stig]

Having the motor in the front of the car is cheaper because thats right next to where the radiator can go.

It would be easy to achieve a slightly front heavy car but the battery would still have to be in between the axles, but placing pack closer to the front axle slightly. The improved traction control of eDrive would prevent any rear wheel spin that might occur when accelerating at low speeds.

 

[Punx0r]

I think some posts in this thread forget the practicalities of car production...

Producing a new car is very, very expensive.

An electric car will (barring a miracle) sell in low numbers

Therefore a manufacturer would lose huge heaps of money trying to produce an EV from scratch.

The obvious solution is to adapt, as cheaply as possible, an existing ICE model.

People put hub motors on bicycles because it's dead simple and fits straight into the existing frame. Similar logic applies to cars. Putting a motor(s) where the ICE used to be is likely to involve new subframes and mounts at a minimum. Better than needing modifications to the monocoque, but still serious $$$.

Mass production tooling is *very* expensive. The sheet steel parts are pressed from is very cheap, but the dies are horrendously expensive. It works only on a large scale, which EV's generally aren't. Someone mentioned that a Honda driveshaft can be had for $100. That's great if that shaft happens to fit the EV you're designing. If it doesn't then the design and tooling for a custom one might work out at $100 each if you buy a warehouse-full...

 

[MitchJi]

Hi,

Probably not what you are expecting :
http://www.greencarcongress.com/2013/12/20131212-protean.html

Protean Electric and FAW-VW developing production-intent electric propulsion system with in-wheel motors
12 December 2013

In-wheel electric drive developer Protean Electric is partnering with FAW-Volkswagen Automotive Co., Ltd. (FAW-VW) in China to develop a new electric propulsion system that will include Protean Electric’s Protean Drive with intent towards a demonstration vehicle program and production.

FAW-VW will create a new rear-wheel drivetrain for an electric vehicle (EV) based on the new Bora compact sedan, utilizing two Protean in-wheel motors. This cooperation began several months ago; all bench testing, engineering calibration and on-site application support is expected to be completed within a year. Protean Electric will also assist FAW-VW in the development of safety and vehicle controls that can be applied to additional vehicle programs.

This is a two-phase project that will capitalize on the torque and packaging freedoms that Protean Drive can bring to an automaker. Our technology will return the space to the new Bora vehicle platform that was formerly occupied by an in-board motor and powertrain.
—Kwok-yin Chan, CEO of Protean Holdings Corp.

Protean Electric introduced its production in-wheel motor at the 2013 Society of Automotive Engineers World Congress in Detroit. Volume production is targeted to begin in 2014, out of Protean’s new manufacturing facility in Liyang, China.

The permanent magnet synchronous motors reside in the space behind the wheel. Protean’s new production motor provides a 25% increase in peak torque compared with the previous generation’s design and can deliver peak output 1,000 N·m (735 lb-ft) and 75 kW (100 hp), with 700 N·m (516 lb-ft) and 54 kW (72 hp) continuous. (Earlier post.) Protean says that its new production motor provides the highest torque and power density of any leading electric propulsion system.

In a paper presented at the EVS 27 conference in Barcelona, Gareth Roberts from Protean and Alessandro Galeazzi from SKF Automotive (a strategic partner of Protean), noted that:

The performance gain with respect to other more conventional arrangements is due to the full integration and synergies created with the mechanical components and in particular the wheel bearing. The final performance is connected to the ability of the wheel bearing to provide the required stiffness that controls the reduction of the air gap between the motor rotor and stator.

… There are three geometric factors that make up the motor air gap: the diameter Z, the motor length X and air gap length Y. For motor performance, it is desirable to maximise the diameter and motor length and minimise the air gap length.

The control of this air gap under different operating conditions is vital to ensuring efficiency and high levels of performance targeted by the In-Wheel motor. Road loads in their worst cases however, represent a significant challenge in maintaining the optimum level of air gap, hence the need to tightly control its variation. Furthermore, there is a risk of magnets touching the wound teeth if too much variation is allowed, with serious consequences for mechanical damage, performance and durability of the In-Wheel motor. The wheel bearing design and in particular the tilting stiffness, influence the design of the motor length and airgap length, which in turn influence the motor performance.

Protean engineers inverted the conventional motor design; the rotor is on the outside and the stator on the inside. This improves performance, makes it compact, and provides space inside the motor for power electronics and controls, the company says.

Each in-wheel motor, with an operating range of 200 - 400 Vdc, comes with its own integrated power and control electronics, which communicates with the vehicle by utilizing a common vehicle control system. Other features of Protean’s in-wheel motors include:

Mass of only 34 kg (75 lbs.) per motor
Integrated friction brake
Superior regenerative braking capabilities, which allow up to 85% of the available kinetic energy to be recovered during braking
Fits within a conventional 18" road wheel

Protean has developed multiple vehicles with various global OEMs for demonstration in the US, Europe and China.

Protean has been awarded 33 patents for its technology and design, with 101 additional international patent applications pending.

 

[gogo]

How hard is it to put all that heavy crap inboard and run an axle out to the wheel? The unsprung weight has to be horrendous.

 

[dogman dan]

I tend to agree with that. but then you eliminate the drive shaft, cv's etc. This frees up space for a big battery tray. But you can still have lots of battery space and use a fairly normal rear differential. Look at a golf cart for example.

 

[John in CR]

The motor only weighs 34kg. That seems to include the brake rotor and caliper, so the unsprung weight compared to a normal rear car hub isn't too bad, at least not for a heavy car. On my 64kg ebike, the motor+wheel+brake+swingarm+battery enclosed in the swingarm weigh more than this big motor. Sure a lot of that has less impact since it's closer to the pivot, but the main weight (motor and wheel) are on a pretty long swingarm.

What I worry about is the motor being on a single sided axle and what is demanded of the bearing. They mention that issue in the article as being a primary hurdle, because it not only supports the wheel, but it maintains the motor's magnetic gap too.

 

[liveforphysics]

I like it.

 

[Punx0r]

Control gear inside the motor? Surely not the controller?