PML Builds 640hp Electric/Hybrid MINI

[MaxDraco]

PML Builds 640hp Electric MINI

Text & Photos courtesy PML FlightLink Ltd.
edited 07-24-2006



http://www.worldcarfans.com/news.cfm/country/ecf/newsID/2060724.006/mini/pml-builds-640hp-electric-mini


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Surely it can?t be an Electric Mini?!
While all the world?s most famous motoring names look on, a British company, PML, has chosen the UK?s most prestigious motor show as the venue to strip away all the misconceptions surrounding electric/hybrid vehicles and to showcase a truly awesome car. Featuring four revolutionary electric wheels, the standard BMW Mini One you can see on Stand 270 is predicted to have a top speed approaching 150mph and to out-accelerate a Porsche 911 Carrera from 0-60mph. Brake horsepower is a stunning 160bhp per wheel - 640bhp in total.

The car, dubbed the Mini QED, has been designed to run for four hours of combined urban/extra urban driving, powered only by a battery and bank of ultra capacitors. For longer journeys at higher speeds, a small conventional internal combustion engine (ICE) is used to re-charge the battery. In this hybrid mode, fuel economies of up to 80mpg can be achieved.

Explains Martin Boughtwood, PML?s MD: ?Until now, most electric vehicles have been little more than souped-up milk floats, limited by range and speed, with compromised performance. For those with a green conscience who also value an enhanced motoring experience, there is still something missing.

?Working in partnership with our customer, Synergy Innovations, we set out to demonstrate what our electric wheel technology is capable of. We simply took a standard BMW Mini One, discarded the engine, the disc brakes, the wheels, and the gearbox. These components were replaced by four of our electric wheels, a lithium polymer battery, a large ultra capacitor, a very small ICE with generator (so small it almost fits alongside the spare wheel), an energy management system and a sexy in-car display module.?

The benefits of PML in-wheel drive technology are;

It is adaptable to other vehicle chassis
It eliminates the need for gearing and mechanical drive train
It allows more space inside the car
The vehicle has three driver-selectable modes of operation:

Eco mode for town/city frequent start-stop driving;
Normal mode for daily commuting and ICE- equivalent operation, and
Sport mode for super car performance.
Other notable features include:

? No (mechanical) brakes means returned energy!

All braking is performed by the wheel motors acting as very efficient electrical generators which return almost all of the energy back to the battery system. The beauty of this dual-circuit, ultra safe system is that your green conscience can be quite content even when accelerating hard, since you are assured of collecting most of the expended energy when it is time to slow down rapidly.

ABS as standard ? even when accelerating
Because the wheels are high performance motors, ABS comes as a standard function built into each wheel?s software. Now anti-skid can also be applied to acceleration since the motor can smoothly control torque delivery to/from the road in both cases. Flooring the brake or accelerator hard merely results in controlled maximum torque, giving the shortest possible stopping or acceleration time.

Clever wheels
The technology eliminates the need for crude differential gears to share power between left and right sides. The wheels are in constant communication with each other deciding 1000 times each second how much torque share is optimum for the current driving conditions. Should one wheel detect a slippery surface and take appropriate anti-skid actions, the other wheels are aware of this instantly and adopt an appropriate compensating strategy to keep the vehicle as stable as possible.

640 brake horsepower ? for life!
Each wheel develops 160bhp - 640bhp in total. The original Mini One develops less than 100bhp with an engine that weighs nearly double the weight of the four electric wheels! Apart from wheel bearings there are no wearing parts in the electric wheels; this means the horsepower stays for the life of the vehicle - and beyond.

Simple, safe, versatile charging
As the battery level reduces, the rear mounted ICE/generator starts to automatically top up the battery. So when you arrive at your destination you can simply park the vehicle knowing that when you return the battery will be replenished. Alternatively you can take advantage of lower cost mains electricity and plug in to recharge. So you never need to worry about battery capacity or how to recharge. During operation, as the battery level falls the generator cuts in, enabling an average speed of 60 ? 70mph to be sustained with no further battery depletion.

Super capacitor ? super acceleration
Capacitors are used to store electrical energy. The difference between batteries and capacitors is that capacitors can release/absorb their energy 10 times faster than a battery. For acceleration or power boost at higher speeds the capacitor enables nitro-like performance, more than doubling the power from the battery during these events. Very efficient energy recovery means almost nothing is wasted during stop/start city travel.

Energy flow management
A significant key to super performance is optimum energy management which continuously decides where the energy flow should be ? battery, super capacitor, generator or wheels. By clever optimisation of the flows, best use can be made of available reserves, enabling a fun driving experience whilst protecting the planet.

Small engine and generator
The small ICE weighs a mere 15kg (less than 1/10th of the original Mini One engine) and delivers peak power of 20kW and continuous power of 15kW. A high efficiency electrical generator is fitted to the engine to provide power when the battery depletion level demands. The key point is that the engine is run at a continuous speed and load ? which results in optimum efficiency fuel conversion. After delivering the energy to the battery system the mileage equivalent translates to between 65 and 80mpg!

In-car display
With all this advanced technology the driver needs to have clear and complete information presented. The in-car display module uses the latest touch screen technology with intuitive display and scroll options. Selectable driving modes allow economy mode to sport boost mode at a touch. Displaying available mileage allocated by battery and fuel along with boost status, the display gives comprehensive information. As well as standard speed, diagnostic and status functions, the display is GPRS enabled allowing future options of:

Remote diagnosis of any fault
Auto tracking of speed limits (optional!)
Auto management of generator to prevent inner city operation
History storage and system configuration interface
QED: What Next?
Having developed it?s high performance in-wheel drive systems, PML worked in partnership with Synergy Innovations to demonstrate, once and for all, that environmentally-friendly Electric/Hybrid vehicles can maintain or even surpass the performance of cars powered by conventional internal combustion engines.

Furthermore, Martin Boughtwood predicts that developments in battery and ultra capacitor technology in the near future will eliminate the need for any charging ICE and generator. Although PML?s Electric/Hybrid Mini will not be generally commercially available, the company is interested in discussing possible one-off orders and collaborations.

Who is PML?
PML (originally Printed Motors Limited) invented and patented the printed armature motor some 40 years ago. The printed armature motor was the first ?pancake? format motor and led the world in compact high performance brushed motors. In the last 4 years, under private ownership, PML has concentrated on the pancake format brushless electric traction ?wheel motor? and wind turbine generators. This year marks the launch of several new products pushing forward direct (gearless) motor drive systems. Synergy Innovations was set up to research and develop alternative approaches to use of the planet?s resources and has partnered with PML over the last 8 months to help turn the vision of the electric Mini QED into reality.

The Mini project was undertaken to demonstrate the super high performance now possible from PML Hi ? Pa drive and QED technology. With very high efficiency, light weight and extreme levels of reliability, PML wheel drive systems are suited to harsh environments needing high levels of safety.

Set to take off in a big way, PML is a British company investing heavily in R&D to take advantage of the benefits of super efficient lightweight wheel motor drive systems in a global economic climate looking for major changes in transport efficiency improvements.

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[Carl Morris]

I was waiting for somebody to do that...but what's the unsprung weight on each corner? As in, how heavy are those motor/wheels? Also, with a true 640awhp, those performance claims seem underwhelming. Perhaps the lack of gears means that the total hp available at lower speeds is far below peak hp? Also I'd expect a much higher top speed...perhaps power is falling off quickly at higher speeds?

[Outlaw]

it has 160 hp per wheel....so on a AWD dyno i think it would only put down 160hp...right or no? for it to perform like an actual 640hp car, it would need to have 640hp at all 4 wheels.... or am i completely wrong and stupid?

[Carl Morris]

it has 160 hp per wheel....so on a AWD dyno i think it would only put down 160hp...right or no? for it to perform like an actual 640hp car, it would need to have 640hp at all 4 wheels.... or am i completely wrong and stupid?

Do you really want me to answer that? :-)

Seriously though, I think it will put whatever horsepower all 4 motors can generate to the rollers. If only one of the 160hp motors were "on", you'd see 160hp at the rollers, right? And what that really means is that the rollers would be accelerating at X revolutions/time/time at Y speed. In other words, X acceleration means different amounts of horsepower depending on how fast the rollers are spinning, just like accelerating in your car at 0.5g requires twice as much horsepower at 100mph than it does at 50mph.

So, when you're putting 160hp to one wheel and generating X acceleration at the rollers, if you fire up a second (or third or fourth) motor the rollers should be accelerated even faster, right? That will show up as additional horsepower in the dyno graph.

[Outlaw]

Do you really want me to answer that? :-)

Seriously though, I think it will put whatever horsepower all 4 motors can generate to the rollers. If only one of the 160hp motors were "on", you'd see 160hp at the rollers, right? And what that really means is that the rollers would be accelerating at X revolutions/time/time at Y speed. In other words, X acceleration means different amounts of horsepower depending on how fast the rollers are spinning, just like accelerating in your car at 0.5g requires twice as much horsepower at 100mph than it does at 50mph.

So, when you're putting 160hp to one wheel and generating X acceleration at the rollers, if you fire up a second (or third or fourth) motor the rollers should be accelerated even faster, right? That will show up as additional horsepower in the dyno graph.


haha, you could call me stupid, its fine, but it sounds like your not so sure... i think with a top speed of not even 150mph, i maybe right.

[Carl Morris]

haha, you could call me stupid, its fine,


Just giving you a hard time, I figured since you asked I might as well harass you :-). If I actually looked down on anybody a second and a half faster than me, that would say more about my stupidity than theirs...


but it sounds like your not so sure... i think with a top speed of not even 150mph, i maybe right.

I'm an engineer, I make an effort not to sound sure unless I've verified it myself. If they really are 160hp motors, and full current is being delivered to them, I'm confident that more than 160hp will show up at the rollers. I'm guessing that the funky top speed is due to the lack of a transmission. An electric motor has a hp curve too, and without the ability to shift into a higher gear they are probably well beyond the hp peak at 150mph. That's the only reasonable explanation I can think of, unless the mfg intentionally limits them at higher speeds.

[Sparetire]

Great. No skill involved in breaking or acceleration. Just fraking great. Huge understeer from massive un-sprung weight. Sweet.

I see bored people.

[Carl Morris]

Great. No skill involved in breaking or acceleration. Just fraking great. Huge understeer from massive un-sprung weight. Sweet.

I see bored people.

You sound like one of those old guys complaining about ABS :-).

I realize lots of unsprung weight will suck for anything less than perfectly smooth pavement. I'm not understanding why it will create more understeer, though? Are you talking about some kind of gyroscopic effect from needing to rotate all that mass that's spinning on a different axis?

[Sparetire]

Yeah, now that I ponder it more, the massive unsprung weight would not nessesarily lead to understeer. In fact that car is overall probably remarkably well sort weight-wise. Talk about even corner weights!

There has to be a way to mount the motors in the car and use a CV shaft to transmit the power to a conventional wheel hub. If they do that then holy crap.

And while I'm 24, I'm a miserly old bastard at heart. Saving food money for DSM stuff in school ensured that :D.

[ErikW]

I may be wrong, but in my observation I've noticed that electric motors have great and even torque range compared to the combustion engine. This would probably explain the fact that this car can keep up with a 911 in acceleration.
Reading on. The on board computer has some sort of control as to how much each wheel uses, thereby using this technique as a clutch and limited slip system. That being said, This could prove to be useful especially when turning the wheel to prevent oversteer (or understeer).
Equal corner weighting could be near perfect. Compare that to the most exotic sports cars out there and they couldn't even dream of this.
150mph? Maybe it's out of it's peak power, but then again, it's hard to think electric motor with no (conventional) clutch system. Without the clumsy clutch parts, the available power now can be used almost instantaneously. This is a major performance benefit by itself.

[Carl Morris]

Yes, electric motors have very nice torque characteristics starting from zero rpm, which is why you can get away with using them without a transmission or clutch. But decent torque at very low rpm is no match for a bit less torque multiplied several times by drivetrain reduction. If the car really has 600+hp, at some speed where the motors are at their "happy" rpm, the car is going to accelerate very hard relative to the competition. But the performance may be relatively weak at low and high speeds, and the performance numbers would suggest that's the case.