The Copenhagen Wheel

[Colin63]

http://senseable.mit.edu/copenhagenwheel/

This looks like technology that could have a real future. Although this prototype is being portrayed as a chic accessory and one which makes separation from a smart phone even more unimaginable for techno sapiens, the ability to harness lost energy and use it to make hills a bit less tiring must have a place in helping weaker or reluctant cyclists out on the road. It even looks good which probably doesn't please the electric bike manafacturers

[Cunobelin]

We rant about motorists using mobile phones.......

The distraction of using a phone to change gears or power must be as dangerous as texting or calling?

[[XAP]Bob]

Presumably the phone is mounted on the bars somewhere, and there must be an alternative means of control....

Mind you it'd never get power, my front wheel does the braking, that's where it's needed - also makes it simpler to retrofit, simpler in design and simpler for control wires...

A front wheel "super capacitor" motor could be kind of fun...

[Colin63]

Are iPhones waterproof?

I'm sure one of these could be run without an iPhone, just a couple of buttons to engage and disengage would be a more universally useful option.

[tali42]

EDIT: Quote correctly attributed (I think there is a bug in the forum software!)

the ability to harness lost energy and use it to make hills a bit less tiring must have a place in helping weaker or reluctant cyclists out on the road.

I am very skeptical of the idea of a regenerative braking system for bicycles.

My immediate question is, how much power do I get back at the wheel after I've used the Copenhagen Wheel to stop, 25%, 50%, 75%..., no system can be 100% efficient in return power when moving off after stopping. It needs to be a lot to justify the extra weight and cost. There isn't any technical data on the website that I can see.

I think that if there has been some breakthrough in this regard, the inventors would be selling the wheel sans the kitchen sink (all the other functions they tout could just as easily be done by a box clipped to your handlebars, or an extension for a smart phone). So why do we need everything but the kitchen sink? Is the regenerative braking a gimic for the rest of the electronics?

I can imagine that it might (if it is very efficient) come into its own riding over undulating terrain where the cyclist would apply the brake continuously when descending to maintain a safe speed and get some of the energy back when ascending. In this case, Copenhagen seems like an odd choice for a namesake, being flattish. And it has to be quite a bit of a hill before I need to ride the brake, usually I just stop pedaling.

[Cunobelin]

the ability to harness lost energy and use it to make hills a bit less tiring must have a place in helping weaker or reluctant cyclists out on the road.

No I didn't!

[MikewsMITH2]

I worked on the development an electric delivery van back in the 70's. It was fitted with regenerative braking, but the main use of the regen braking was to prevent excessive brake wear caused by the lack of engine braking which is experienced with conventional internal combustion engines magnified by the greater weight of the vehicle due to the battery pack. The regen braking actually didn't put much power back into the batteries as it generated too high a current over too short a period and it simply isn't possible to get the charge into the batteries in the short time of a braking cycle (typically a few seconds) without overheating and damaging the batteries. We were using lead acid batteries. the problem may not be quite as bad with some newer battery technologies which will allow higher charge currents, but batteries are still relatively inefficient at storing energy. People don't normally worry too much about the efficiency of charging batteries as mains power is cheap and plentiful. Also it is difficult to design one machine which functions efficiently both as traction motor and a generator. Controlling regen braking isn't a simple push button affair either. The driver (rider?) has to be able to modulate the braking in order to slow down and stop smoothly and the battery temperature and charge current has to be carefully monitored to avoid damage to the batteries and overheating the motor/generator

i worked on "shaping" the accelerator and braking response so that the driver could accelerate and slow down smoothly, Remember this was before the invention of the microprocessor so it was quite complex analogue engineering. The smart phone would do an excellent job comparitively.

Regen braking would work best as a "drag brake" for descending long hills so the waste power could be got efficiently into the battery pack. I suspect the reason why the wheel is fitted to the back is that it isn't a very effective brake and the front wheel is needed for conventiona lbraking to be able to stop quickly! if they have succeeded in making this wheel useful then it is no small achievement. On the other hand it might just be a big spring. like in those pull-back toy cars. That might work better in fact! I wouldn't mind one on the tandem!

[thirdcrank]

We rant about motorists using mobile phones.......

The distraction of using a phone to change gears or power must be as dangerous as texting or calling?

Haven't you heard of handsfree?

[fivebikes]

My car, a Toyota Prius uses regen braking quite well. Any deceleration or downhill motion recharges the NiMH battery pack which can provide enough power for a leisurely (below 30 mph) drive for a few miles providing no sudden acceleration is required. Enough to get through a town centre such as Huddersfield for example. A couple of miles of non polluting driving in an urban environment shared by cyclists and pedestrians has got to be good!
The technology is pretty sophisticated and is expensive...I believe Toyota made little or no money on the cars and this may still be the case. The batteries and electric motor are weighty too so aluminium panels are used to compensate. I guess from all of this the Copenhagen could be pricy!
To be useful as a motive energy source in a bike I'm guessing the weight of adequate batteries and ancillaries would be significant and the unit looks pretty small to pack any kind of punch!
I'm not against powering stuff from a bike, I have dynamos on my Brompton and old Claud Butler which are great but excess energy saved after lighting only provides 5 or 6 mins of standlight power when stopped. I know this is stored in a capacitor rather than a regular battery but I can't begin to guess how long it would take to recharge a pair of AA cells for longer run times.
As for the wheel, all the smart phone and pollution monitoring stuff looks a bit like a Clive Sinclair idea of the C5 variety! The pics even echo that design in some ways.
Whilst more than a little sceptical about the wheel's real world benefits I'd love to be proven wrong! Maybe in a few years we will be retrofitting them to our Mercians etc!
Cheers!

[fatboy]

Another perpetual motion machine! I don't reckon that the sums would add up for this and you'd expend more extra energy by having this thing than you'd ever get back. All that extra weight in the wheel has to be hard to get started. I reckon that a bike with gears would be better and that's just what I've got!

I have to say that I don't get the Hybrid car idea in terms of reducing fuel consumption as the power to charge the battery could be used to drive the wheels. Also the batteries mean that the car weighs more, so the only thing that might do a bit is regenerative braking.

Overall I'm not convinced by Hybrid cars and this bike is no more convincing to me.

[Si]

An epic case of trying to re-invent the wheel?

All that extra weight to accelerate or to climb with vs what you get back from it? Not sure that it's a trade off I'd go or. hen you ad in the faff of having to have an
expensive phone attached to the bike and changing gear on a small screen that's jumping about all the time - nope, not for me.

I can see that there might be a bit of mileage in the regen braking but tying it in to the phone is just adding bells and whistles for the sake of it. The beauty of a bike, to me, is its simplicity.

I think that learning to anticipate what's happening up the road such that you have to brake less would be a suitable first step before getting one of these things.



Also, chain's a bit slack.

[mark_w]

So what happens when your phone crashes or the App won't load when you want to go out for a ride?

I think the regenerative braking and almost 'kers'-type boost of power is a nice idea, but I agree with Si - unless it's uber-light it'll be an overhead on top of something that isn't needed anyway. And if it was uber-light, it would also by design be uber-expensive.

Someone was telling me that the in thing in 2010 will be wireless gear change systems (Shimano Di2 et. al.) which worry me - what if your controller battery dies during a race, or you end up controlling someone else's gears? It's a nice idea but heavily open to abuse.

[frank9755]

I worked on the development an electric delivery van back in the 70's. It was fitted with regenerative braking, but the main use of the regen braking was to prevent excessive brake wear caused by the lack of engine braking which is experienced with conventional internal combustion engines magnified by the greater weight of the vehicle due to the battery pack.

Regen braking would work best as a "drag brake" for descending long hills so the waste power could be got efficiently into the battery pack.

Presumably this is some sort of design project, not an actual product.

Regenerative braking has been looked into by electric bike manufacturers, but hasn't taken off because bikes simply don't generate enough energy, being far lighter than cars and mostly travelling at slower speeds. It's a good idea in theory but in practice the small benefit is not worth the effort. There is only one mainstream e-bike manufacturer which does use it - the (high priced) Canadian firm, Bionx. But even for them the regenerative aspect is just a way to increase the range between charges slightly, not the main power source.

[MikewsMITH2]

Presumably this is some sort of design project, not an actual product.

Oh no it was a real vehicle. Leyland vans provided the vehicle platform, Chloride the batteries and CAV the motor,I have a pic somewhere in the loft of the DofE riding in it. It went into limited production and Midland Electric amongst others had a fleet of them driving around Birmingham. Top speed was around 40 MPH and range about 50 miles. If you look at the attachment you will see that at least 350 were built. Later on they built a taxi and a hybrid car like the Prius (so don't think Hybrid is a new idea).

See this link http://www.sae.org/technical/papers/840477

There are also papers on regen braking in the SAE archives.

It took more than 12 years to get into production though, I was working on it in 1972!

I would imagine the Copenghagen wheel would also put power into the batteries whilst pedalling on the level too. This might work well in flat Denmark. Not sure about hilly Dorset though! BTW the Prius uses the petrol engine to charge the batteries. The regen braking will put little into the batts.

[frank9755]

Mike,
Apologies!
I meant that I thought the copenhagen wheel was a daydream rather than a serious project, not your work.
I can see that using the qoute from you as evidence made it look otherwise, and made my post appear a bit rude! Not my intention at all - very sorry!