IMO; I think it could go a long way to making electric vehicles and hybrid vehicles more of a viable alternative to gas and/or diesel powered vehicles.
Glad to hear this company hasn't fizzled out. I've been watching these motors since PML flightlink first put them in a mini: www.gizmag.com/go/6104
Hopefully they will become available to consumers once mass production hits full swing, not just to OEMs. I would gladly invest in four motors and the master controller, maybe even two sets. With the longevity of well made electric motors it could be integrated into something like the "skateboard" concept. With the powertrain integrated into a base unit and the rest of the vehicle being modular so it can be upgraded and reconfigured as the owners needs change. You buy your first vehicle then instead of buying a new everything ever 5-10 years you just replace the part that is cheaper, based on car experts stating the power train is 66% of the cost of a vehicle.
I was hoping for some comment about the (supposed?) problems with unsprung weight. The 31Kg (per wheel) is going to be quite a thud, making for a rough ride and handling problems, or so I have been told.
Of course, most people are more interested in motors with a half or a third of that power and even less in torque.
Each wheel weighing 31 kg + rim + tire? What about unsprung mass and it's influence on car's driveability?
Every time someone shows a good example of in-wheel motor (there have been in-hub engines as well) I imagine that those people do not have a clue about the suspension dynamics.
In-wheel motors are well only for cars that travel in straight line on perfectly smooth surfaces.
So unless the weight of the motor is down to say about tenth of it's current mass (impossible I believe) it's a big thumbs DOWN.
well, you are forgetting that normal gas engined cars have gearboxes and final drives. pretty sure that when taking ratios into consideration you can get cars with more first gear torque than that
and unsprung weight is also an issue. add the weight for brake components, rim and tyre and you'd be looking close to 50kg.
cornering is compromised too. would really be a massive gyro
Protean Electric has published studies done on the issue of unsprung mass and its effect on the vehicle, one of which is called 'Unsprung Mass with In-Wheel Motors - Myths and Realities' which can be found here:
It is not as if they don't know what they are talking about, like some of the people make out here.
Angus, I'm sorry to say this but you were so busy trying to write clever prose "According to my math, those torque numbers destroy any gas powered options that currently exist" that your forgot to actually do any real thinking or math. Don't feel too bad though, you're not the first to make this mistake, possibly Protean's web site doesn't help to dispel the myth. The Protean motor makes it's torque at the wheel while a conventional V8 has about 10:1 in reduction through the transmission and differential to the wheel-- so a mid-range 400 ftlb V8 makes 4000 ftlb of torque at the wheel in 1st gear, pretty much destroying the Protean for off-the line performance.
"so a mid-range 400 ftlb V8 makes 4000 ftlb of torque at the wheel in 1st gear"
And how much smoke does it generate at the wheels when it does this?
Unsprung mass is a problem for 'dumb' systems; which frankly aren't that great even with regular 'light' wheels. Individual wheel monitoring should mitigate grip problems, and smarter suspension should better handle shocks. More complexity is not ideal, but it is probably worth the potential fuel savings, possibly offset by a reduction in drive train complexity, and might actually produce a more comfortable driving experience.
Make it fully sealed completely waterproof and dust / dirt / mud proof and you have the basis for an extremely capable 4WD. Forget about batteries and fuel cells for now, spend R&D dollars and effort making better electric motors and run hybrid systems until the batteries catch up. A small battery bank coupled to a standard ICE motor stripped down to do nothing more than act as a generator, no gearbox, no drivetrain - to me this is the short term win-win situation.
Studies that support the position of the company that commissioned the study are always suspect especially when it goes against decades of experience. I never made the change from steel to light alloy rims in a car where it made a notable difference but a friend that put steel roll-flat inserts into his truck said, "It makes the truck handle like a pig but my mom and baby sister can now drive it someplace safe if they get a flat."
I would probably get along just fine with the weight but I think electric hybrids are just stupid. I'll use a much more cost effective system.
Unsprung mass is sure an issue, though generally overrated. Even with the math done right, the performance of this motor is way greater than the average electric car will ever need, and you could mount four of these, so it will be possible to make it much lighter in the end.
I've put steel rims on my electric car during winter. It wasn't all that bad, given the speeds I drive and the usual route I take. We're not talking race cars here, are we?
Then, as an experiment inspired by a friend of mine, I chose to use narrower tires and steel rims (135 instead of 185), and that more than compensated for the steel rims' weight and increased range by nearly than 10%. I'll keep the steel rims now. There is no use in putting super wide tires on cars if you want efficiency. Everybody does presentations with super wide tires because it looks cool, but they simply don't make sense in everyday life. This says someone who lives in a country that has no speed limits on highways. It makes even less sense in most other countries.
Passing from the 1990's American gasoline automotive paradigm to the 21st century practical and pleasing Electrics may find the casting off of many, once necessary features, remembering of course, the first cars we actually sold with buggy whips attached?
My Questions: Can very much higher voltage systems - 1, reduce hub motor masses? - 2, reduce storage systems masses? - 3, reduce recharging times?
Transmissions. They multiply torque. A lot.
They didn't cover it in this article so the confusion over unsprung weight is understandable. If you look at this article http://www.gizmag.com/go/6104/ which was their first demo and a retrofit not a completely new design, they state: "The in wheel motors and magnesium alloy wheels, and tires, have a total mass of 24kg. The original assembly mass on the MINI One was 22.5kg. With so little difference in unsprung mass…"
The unsprung weight is actually impacted very little. To understand these motors you have to re-imagine the automobile. These motors replace pretty much everything we have become accustomed to in vehicle design. There is no longer an “engine” or gas tank but this weight is replaced by controllers and batteries. On the ground side of the suspension there are no calipers, disks or brake pads, no driveshaft/transaxle, nothing at all between the "engine" compartment and the wheels but cables connecting to the master motor controller and these motors. The mounts for these will look very much like the non drive wheels on current cars.
When doing the mental math it is first necessary to subtract all that mass before adding in the mass of these motors. Since it looks like in this iteration they have fully integrated the motor into the wheel you can subtract the weight of the wheel as well leaving only the tires as residual unsprung weight. Taking into account for how much unsprung mass is removed prior to adding these motors I’d be surprised if anything but the smallest cars experienced a significant unsprung weight increase.
VirtualGathis makes some good points, but unless the wheel motors can do something (like reverse polarity?) to get the car to a complete stop and to hold on a hill, the brake componentry will need to remain. However, if the wheel motors can recover 85% of the kinetic energy during braking, it may follow that the brakes could be much smaller than normal.
Bruce H. Anderson
I understand the concern about unsprung weight. I do agree with Routledge. Active suspension systems would handily solve that problem. I'd like to see more diesels running at constant speed- no more than 1000 rpm. in hybrid cars though.
I find this intriguing; but I'm a proponent of keeping un-sprung weight light. If they could reduce the weight and size by dropping the output to 200 ft/lbs. and move the motors inboard to where the differential would be on a normal car; they might have the start of a practical lightweight powerplant for a fun sportscar or just plain economy transport.
I understand the concern of excessive unsprung weight affecting handling of the vehicle. I find it interesting that nobody mentioned the fact that a lower center of gravity will greatly increase the handling and may even completely offset the difference caused by additional unsprung weight. Looking at most sports cars, the engine is the largest single source of weight in an automobile other than the body and chassis. Where does the motor sit...on a plane that is considerably higher than the axles of the vehicle. Take the combination of eliminating that lever when in a corner along with the ability to independantly apply power to any one wheel during cornering and you have a vehicle that will handle very, very well.
I think this would be a great add on for all then fuel efficient fwd cars, could act as a great way of reducing fuel used in the low speeds and gears.
Check out RST-V from General Dynamic Land Systems: 4 motor-in-wheel, all terrain military vehicle. It has the same top speed of the Humvee it replaces, and leaves the Humvee in its dust in every other test.
re; Stephen Wyman
Did they happen to compare price?
The main issue I have come across with unsprung weight is hitting potholes and corrugations in the middle of a corner with the centrifugal effect.
The could be fairly awesome as the rear wheel in a trike with either batteries as a floor and possibly a generator over/next to it. Just remember to put some storage space in the nose
There are a couple of coments about the weight at 31kg per wheel impacting handling. I recently pulled a Mazda MX5 apart and the sprung mass each is about 40kg per corner. This includes the tyres and suspension arms, but it indicates that 31kg for the hub, brakes and motor doesn't look too bad.
@Bruce H. Anderson - These motors have an integrated parking brake that is not reliant on electricity. As far as stopping an electric motor. To see how this works in person get an electric motor with a light load on it, for safety, get it spinning then short the leads. It'll bang to a stop very quickly. There is a link to the explanation form a motor manufacturer below. This reverse field that it creates is the reason regenerative braking is possible with electric motors. The mini QED reports stated that they were able to get nearly the full strength of the motor as brake force so it demonstrated the equivalent of 600hp of brake force with no friction braking whatsoever. Trains use it today as "dynamic braking" to preserve the life of the friction brakes. Instead of recovering the energy though it gets dumped as heat via a resistive coil.
Here is an explanation of electric motors stopping themselves: http://www.electricmotors.machinedesign.com/guiEdits/Content/bdeee5/bdeee5_3.aspx
Build me a COE (Cab Over Engine) styled utility , pick up, van, or crew cab with one of these motors on each corner! We have seen the end of the long nosed U.S. styled gas guzzling bullshit and good riddance to it.
Electronic/active suspensions have been invented 20 years ago and they costed a lot; with today technology they should be a lot more reliable and a lot more cheap, so I don't see the reason to still keep applying passive suspensions to modern cars. (?)
Probably even an Arduino at 16 MHz could handle needed realtime processing for an active suspension! :-) But 20 years ago we had 16 MHz desktops!
@ Luca Sentini "They" have fitted todays cars with "active suspension"....The "Magic Ride" system of the S Class Merc is a true "active system" it looks at the road ahead and accurately readies the shocks/springs to suit, very clever.
But the turbine/electric motor cars were promised as the "Future Car" in 19402/1950s Jaguar/Chrysler designs, and very good they both were too.