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gruff

car power

now this is a good idea and i hope it takes of.
http://news.bbc.co.uk/1/hi/england/somerset/4535408.stm
sally_in_wales

That is such a good idea, can you imagine how much could be generated by a few of those at busy road junctions!

Wonder how practical a scaled down version would be built into all your household steps! Could you actually generate anything worthwhile?
Bernie66

Could "traffic calm" and power the street lights. Feel A little sorry for the cyclists if the councis put them every 20 yards though!
sally_in_wales

Perfect example of why seperate cycle lanes are necessary! Agree it owuld probably be very uncomfy to cycle over
Milo

It's a wonderful idea!!

I think a lot of cyclists would enjoy it though, bunny-hops galore! called. It could liven up a journey.
2steps

thats a great idea Smile
Treacodactyl

Erm, this means petrol/diesel energy is being used to power traffic signs, cars will have to use higher revs to get over them burning more fuel. I would have thought solar or wind would be a better source of power, especially if they cost 25k each.
dougal

I wondered how long it would be before anyone spotted that!

Its pretty silly from an energy point of view, in almost all locations.
Its pretty expensive for a speed bump.
And the cost doesn't allow for the need to keep trafficlights working when there is little traffic - like at 3am on Sunday morning. Batteries and their controllers are extra. And need looking after.

The company's website refers to it using "waste kinetic energy" from the traffic.
The energy is only being 'wasted' if a vehicle is under braking when it crosses the 'ramp'. Otherwise useful energy is being stolen, and will be replaced by burning more petrol/diesel. And economically its inefficient because the road fuel petrol/diesel is taxed massively more than power station fuel.
The ramp needs to be in a zone where the traffic is slowing - but should never stop, (which would block the ramp). Generally, IMHO, traffic lights don't work like that.
However most motorway exit slip roads *do* work like that. But I'm not keen on the idea of high speed (50/70 mph?) traffic hitting such an obstruction.

I rather think that there might be a considerable road safety issue. Especially when the road surface is slippery.

And the *amount* of energy being generated is *tiny*.
They talk glibly about generating at 5 to 50kW. Firstly that is a rate. And I think that it can only apply during the fraction of a second that a wheel is squeezing the ramp. (A small car engine, like a VW Polo, generates 50kw flat out - imagine a sudden momentary slow down like having 10% of maximum power being applied as reverse thrust - not pleasant or comfortable.)
However, how much of the time is the ramp going to have a wheel crossing it? IMHO much, much less than 1% of 24/7. So instead of generating 5 or 50kw, its *overall* average performance might be 50 watts or so - not enough for 1 light bulb.

If people treat it like a speed bump, slowing down beforehand, crossing gently and then accelerating away - the energy stolen by the ramp will only be a tiny fraction of the energy wasted in slowing down and reaccelerating.


This idea, once examined in detail, seems so daft that it should have been killed before it even got onto the drawing board.

If the energy used to operate traffic lights were significant - which I strongly doubt - then lets have laptop-technology low wattage controllers and LED 'bulbs', and buy in renewably sourced electricity to run them. Much cheaper, much simpler and much better for the environment.
Mat S

I'm with Dougal - about as clever as putting a wind turbine on top of your car.
sally_in_wales

Shame Sad I thought it was a great idea- but I was assuming it would work fairly well as the report said it had been tested and all that. Oh well. I still like the idea of being able to 'claw back' some energy from moving traffic, but do accept the whole laws of physics thing
Rob R

No point me re-typing what dougal has so eloquently explained- When I first read the post I was beginning to think it was something to use the engines tick over power when stationary or the wasted heat from exhaust- if someone can come up with an idea on those lines, then we really are reducing waste. Smile
Milo

Well, WW, don't be deterred by the negativity - I still like this idea, as an idea and I guess if everyone stomped on the ramp as hard as they've recently stomped on the idea, then that'd generate some energy too.

Doubtless the gearing can be modified to create more below ground action relative to the distance that the ramp is depressed and the cost would be very likely to come down as it does with nearly every new "gadget".

I can't find an official website for the ramps, but would question that the speed at which the ramp is depressed is particularly relevant to power output and surely, in my non-scientific opinion, it is not beyond possibility that a lengthy succession of ramps located in an area where the speed limit is already low would be very effective.
Treacodactyl

I'm sure there's a bit more to them than the story, such as a cunning way of installing traffic calming measures and claiming they are a good way of generating power. I wonder what sort of power they would get from a solar and battery set-up for the same price?

As for the principle of energy is never created, it's just changed from one state to another I'm afraid not much can be done with that one. Wink The energy generated comes from the fuel in the vehicles. Ideas that harness the breaking energy and store this to power an electric motor to start the vehicle off again are great ideas provided their extra weight doesn't outweigh their gains.
Milo

Quote:
a cunning way of installing traffic calming measures and claiming they are a good way of generating power.


Well, sokay by me. Driving is a dangerous activity, so traffic calming measures are good, aren't they.

Quote:
The energy generated comes from the fuel in the vehicles. Ideas that harness the breaking energy


Or braking? As in slowing down? It's got to be done, hasn't it. Just a question of where really. Perhaps it's quite possible to drive over sensibly located ramps at 30mph in a high gear and accelerate away at the end of a succession of ramps as one would quite normally from a speed hump.

Quote:
and store this to power an electric motor to start the vehicle off again are great ideas provided their extra weight doesn't outweigh their gains.


What extra weight, Treo? (This is getting heavy, dude!).
Treacodactyl

Milo wrote:
Well, sokay by me. Driving is a dangerous activity, so traffic calming measures are good, aren't they.


I'm not that keen on many of them but that's a whole new topic. Having had a speed bump cause a potentially very dangerous failure on my cars suspension, while driving over one at less than 10mph, they are another scheme that penalises everyone rather than the bad drivers IMHO.

Quote:
The energy generated comes from the fuel in the vehicles. Ideas that harness the breaking energy


Milo wrote:
Or braking? As in slowing down? It's got to be done, hasn't it. Just a question of where really. Perhaps it's quite possible to drive over sensibly located ramps at 30mph in a high gear and accelerate away at the end of a succession of ramps as one would quite normally from a speed hump.


Where are these humps to be mounted? Near traffic lights where cars will have stopped already and then accelerate over them to drive off? Even if they are sited so that cars hit them at speed most good drivers would slow down before they got to the 'bump' in the road and then drive, i.e. accelerate, over them. That's good driving.

Quote:
and store this to power an electric motor to start the vehicle off again are great ideas provided their extra weight doesn't outweigh their gains.


Milo wrote:
What extra weight, Treo? (This is getting heavy, dude!).


To store the extra electricity you would need a larger or additional battery, nip into a garage one day and try and lift one. You would also need a method of converting the energy from kinetic (motion) to electrical so a generator would be required. There are various designs out there if you wish to google.
dougal

Milo -
I hope you noted my positive suggestions towards the energy cost of traffic lights.
These ramps are a daft solution to an essentially non-existant problem, and are likely born out of a lack of understanding of the basic physics/science/engineering.
These things would be an expenditure of quite a lot of money, specifically in order to increase petrol/diesel consumption.
Bad idea.
If you really want to see the promoter's website, its linked at the right hand side of the BBC page http://www.hughesresearch.co.uk/

If we can get beyond the concept that *all* energy used for personal transportation is wasted, and assume the journey is needed, the driver reasonably skilled, the car appropriately sized and well maintained, etc...
We eventually get to the point when we can say that the only time that energy is really and truly being *wasted* is when the vehicle's kinetic (movement, proportional to the speed squared) energy is dumped as heat energy during braking.
{Incidentally, this leads to the realisation that much of the skill of (fuel) economical driving is to *minimise* the use of the brakes, by thinking ahead to avoid unneccessary acceleration and pre-emptively lifting off early instead of braking hard and late.}
Causing traffic to slow down suddenly (dumping kinetic energy to brake heat) is bad for fuel consumption. And pollution. Hence enlightened traffic management is about keeping the vehicles movng steadily (not braking and accelerating) and maintaining a safe and appropriate speed.



However, as TD notes, there are other ways to absorb the kinetic energy and slow the vehicle, rather than simply dumping it as frictional heat.
Today, you can buy "hybrid" cars from Honda and Toyota that slow the vehicle by 'engaging a dynamo to charge a battery'. When the car accelerates away, the battery-stored energy drives an electric motor to return the energy to the form of kinetic (movement) energy.
That is a simplification of how these hybrids work. But its broadly true.
Other systems have been tried, including using hydraulic chargers/motors and storing the energy in a spinning flywheel.
I think that the electric ones are the only ones that have made it to the point of going on sale.
The problem that TD notes is that this extra kit (motors/chargers and batteries or their alternatives) adds to the weight of the vehicle (batteries are not light) which tends to make it more thirsty on fuel, and carries additional resource costs.
{Side note - a hybrid engine permits the vehicle to be more efiicient, but it doesn't per se make it an efficient vehicle...}

One technical problem with today's hybrids is that today's batteries cannot be fully charged really, really quickly - like during a few seconds of braking. So some, but nowhere near all, of the braking energy wastage can be avoided, and only some of the energy can be reused.
In the near future, I expect Nanotechnology batteries (prototypes already demonstrated) to be able to absorb much more of the braking energy, because their Nanotech design permits much faster charging.
Milo

I hope you noted my positive suggestions towards the energy cost of traffic lights.

Yes.

These things would be an expenditure of quite a lot of money, specifically in order to increase petrol/diesel consumption. Bad idea.

You've lost me, (it's not difficult!), but you're surely not saying that these ramps might be put in place in order to increase fuel consumption.

If you really want to see the promoter's website, its linked at the right hand side of the BBC page http://www.hughesresearch.co.uk/

Course I do, but it won't open at present.

the only time that energy is really and truly being *wasted* is when the vehicle's kinetic (movement, proportional to the speed squared) energy is dumped as heat energy during braking.

{Incidentally, this leads to the realisation that much of the skill of (fuel) economical driving is to *minimise* the use of the brakes, by thinking ahead to avoid unneccessary acceleration and pre-emptively lifting off early instead of braking hard and late.}

Indeed, and so with adequate warning one can take ones foot off the accelerator and without braking reach the right speed for driving over the ramps.

Causing traffic to slow down suddenly (dumping kinetic energy to brake heat) is bad for fuel consumption. And pollution. Hence enlightened traffic management is about keeping the vehicles movng steadily (not braking and accelerating) and maintaining a safe and appropriate speed.

No probs with that. And I take your points about the hybrids, but can't (yet) see their relevance to the ramps.
Treacodactyl

Milo wrote:
Indeed, and so with adequate warning one can take ones foot off the accelerator and without braking reach the right speed for driving over the ramps.


No. You should never tackle a ramp at speed so a good driver would slow and then *drive* over them. You also seem to forget that there is likely to be a stationary car infront due to the concept of queues at traffic lights.

I mentioned hybrid cars as an example of a *better* way to harness excess braking energy.
dougal

dougal wrote:
These things would be an expenditure of quite a lot of money, specifically in order to increase petrol/diesel consumption. Bad idea.
milo wrote:
You've lost me, (it's not difficult!), but you're surely not saying that these ramps might be put in place in order to increase fuel consumption.

The ramp takes energy from the car.
The car's energy comes from petrol/diesel.

The only way the ramp can take energy from the car *without* increasing fuel consumption is if the ramp ***substitutes*** for the car's brakes to slow the car.
The actual slowing down must be achieved ***by*** the ramp itself (NOT slowing down **for** the ramp).
**Any** other energy taken by the ramp is achieved at the direct cost of additional fuel consumption.
**Any** additional slowing beyond what the traffic would do without the ramp costs extra fuel.
**Any** slowing specifically *for* the ramp, wastes additional car fuel energy to the brakes, increasing the fuel consumption while generating no extra energy in the ramp - ie it reduces the efficiency of generation.

The ramp energy comes either as a *substitute* for brake heat or from extra fuel consumption.
There is no such thing as a "free lunch".


milo wrote:
I take your points about the hybrids, but can't (yet) see their relevance to the ramps.
The ramp claims to reclaim some of the energy 'wasted' on braking, but only at particular points on the road network.
'Hybrid' vehicles do reclaim some of the energy that would otherwise be 'wasted' on braking - every time they slow down, everywhere they go. And do it today.

I believe that the tiny amount of energy such a ramp might generate would be achieved at the expense of the wastage of lots of *additional* petrol/diesel.
As Treacodactyl noted, the Hybrid loses some of its extra efficiency by carrying around batteries and motor/generator. However, the practical results that such vehicles give show that its well worthwhile to transport the extra kit. They *do* achieve better mpg - they *are* more fuel efficient.

I strongly doubt that these ramps would generate much power - and lets talk kWh 24/365 rather than instantaneous kW rates as a vehicle crosses the ramp - and what little was generated would be at a cost of additional fuel consumption, making the power generation grotesquely inefficient.
jema

Coming in late here, minute I started reading this thread though I thought doh basic physics "conservation of energy" someones trying to get something for nothing and that simply does not work Sad

I am trying hard to convince myself that the criteria so eloquently explained by Dougal that the ramp must substitute for when a car would be breaking, can be met in any real and significant way Confused I can think of some roundabout approaches on dual carriage ways where it might just work. But i'd need some serious convincing even there.
cab

Apologies for taking this all in a rather light hearted way, but I'm reminded of this article here:

http://www.sullivan-county.com/id3/thermodynamics.htm

This is basic thermodynamics. Unless the energy here is being gained by using the cars deceleration (so you'd put a device in a location where cars are slowing down anyway, and take a cut of that reduction in the cars momentum), and it doesn't loook like it really is, then this device is merely a way of using some of the cars fuel to power the lights.

If you're going to have traffic calming measures anyway (there's an oxymoron if ever there was one!) then by all means get some of the wasted energy out of them. But there's no such thing as a thermodynamic free lunch!
Milo

Never while posting on any topic on any forum anywhere have I felt so perplexed and apparently misunderstood (and been almost accused of being a crap driver), but I'm still of the opinion that a competent driver can, without braking, slow his vehicle to a speed suitable for driving over ramps (whatever they might be powering).

Locations abound where a reduction from 40 to 30 and back to 40, or from 30 to 20 and back to 30mph in an urban setting is entirely appropriate and I don't expect it matters greatly if the ramps are not located right alongside the equipment requiring the electrical power.
Treacodactyl

Milo wrote:
Never while posting on any topic on any forum anywhere have I felt so perplexed and apparently misunderstood (and been almost accused of being a crap driver)


May I suggest it might have something to do with being too idealogical without thinking through the facts? When it was first pointed out that the laws of physics meant the energy would come from fuel you appeared to try and say the laws could be changed. Laughing

Going back to the ramps, I bet if you ask a driving instructor what you should do with a speed bump they would say slow right down and drive over it. I suppose you could train drivers to no do this on these new ramps but I doubt I would listen as what happens when they stop working? Either through a fault, debris lodge in them or a vandal wedging something in them? Hitting one at 40mph that stay up who knows what may happen.
Behemoth

The only way I could see these wroking is in sequence like the 'speed cushions' we seem to have a lot around here. These you can drive over without discomfort if you 'hit' them at under 30mph and straight. Put a sequence of these in along a road and you limit the max speed to 30 without any braking. Any faster and you start to get jarred and enter a stop/start way of driving. However, I'm sure it would take some driver education to convince us that you shouldn't slow down when confronted with a metal ramp in the road.
sally_in_wales

I'm still disappointed that it doesnt seem to work Sad When I read it I was under the impression it was the weight of the car passing over the splunger, rather than the forward momentum that worked the uppy downy thing that generated the power. However, physics was never my strong point Rolling Eyes
Behemoth

Physiscs was made up by a Yorkshireman - bascially you don't get owt f' nowt.
Treacodactyl

sally_in_wales wrote:
I'm still disappointed that it doesnt seem to work Sad When I read it I was under the impression it was the weight of the car passing over the splunger, rather than the forward momentum that worked the uppy downy thing that generated the power. However, physics was never my strong point Rolling Eyes


It is, but for the weight of the car to press down something has to power the car up onto the ramp in the first place. If the car is almost stationary, for example in a traffic light queue, then you would have to use extra revs to get onto the ramp.

I'm sure there's more to the story than the article though. i.e. reasons for the ramps that's not been mentioned.
cab

Milo wrote:
Never while posting on any topic on any forum anywhere have I felt so perplexed and apparently misunderstood (and been almost accused of being a crap driver), but I'm still of the opinion that a competent driver can, without braking, slow his vehicle to a speed suitable for driving over ramps (whatever they might be powering).


That, depending on the location, can be true.

Quote:

Locations abound where a reduction from 40 to 30 and back to 40, or from 30 to 20 and back to 30mph in an urban setting is entirely appropriate and I don't expect it matters greatly if the ramps are not located right alongside the equipment requiring the electrical power.


But the car is still losing kinetic energy, it is slowing down. To speed up again costs more energy.

If the ramp is the causative agent of slowing the car down, then it might be a good way of getting energy out without waste. That would mean (1) rapid, uncomfortable deceleration, (2) damage to the car, and (3) absorbing one hell of a shock.
Milo

Quote:
The only way I could see these wroking is in sequence like the 'speed cushions' we seem to have a lot around here.


That's how I imagined these to be.

Quote:
These you can drive over without discomfort if you 'hit' them at under 30mph and straight. Put a sequence of these in along a road and you limit the max speed to 30 without any braking. Any faster and you start to get jarred and enter a stop/start way of driving.


Sounds just fine to me, IF located within a stretch of road where it makes sense for the speed to be 30, (or less).

The photo with the Beeb's article is from a curious angle. From the diags on the inventor's website the burmps do appear to be small and gentle.
Rob R

I think perhaps there is a point being missed on this article- having looked at the article again, the point of the ramps seems to me not to be a way of reducing energy wastage or reducing CO2 emissions from power generation but rather it is about generating *free* power for the local authorities. Or to put it another way, getting the motorist to pay to power the street lights & signs (despite them trying to deny this in an FAQ).

Basic physics shows that energy is constant- it can neither be created nor destroyed, only its form can be changed, not its existance. The clever bit of this invention seems to be in basic economics, however, as a cost cutting exercise for the authorities. Rolling Eyes
Milo

Quote:
The clever bit of this invention seems to be in basic economics, however, as a cost cutting exercise for the authorities.

But not therefore necessarily a bad thing?
jema

Milo wrote:
Quote:
The clever bit of this invention seems to be in basic economics, however, as a cost cutting exercise for the authorities.

But not therefore necessarily a bad thing?


By that definition very much a bad thing! Authorities up pollution as a cost cutting exercise Sad
Rob R

Depends on your perspective- unless they are very carefully positioned, they are bound to cost the motorist (and the environment). The idea that cars only slow down at traffic lights suggests to me that it is a cost saving exercise 'pretending' to be something it isn't.
tawny owl

Milo wrote:
Well, sokay by me. Driving is a dangerous activity, so traffic calming measures are good, aren't they.


But not speed bumps - they're inefficient and dangerous in themselves, particularly when many councils ignore the rules about what height and length they're supposed to be.

Many ambulance services are very unhappy about them, with good reason. If there were to be loads of these all over the place, as the article hints, then it could well cause huge problems during patient transport, particularly for spinal injuries.

Even to private owners - what if you were carrying your frail granny or your poorly cat in the back and had to go over a long series of these bumps? Even taking great care, you're still going to cause great discomfort. Or a kid who has a tendency to get car sick? From personal experience, I can tell you a load of speed bumps is almost guaranteed to set off a puking fit. In addition, I reckon having as many as is intimated in the article will end up damaging cars over a long period of time, thus contributing to waste, on top of the lost power.
cab

tawny owl wrote:

But not speed bumps - they're inefficient and dangerous in themselves, particularly when many councils ignore the rules about what height and length they're supposed to be.


As a cyclist I despise them. Motorists often have a habit of tearing up to them, going past you, and then pulling right in while braking in front of you, as they try to pick the best line over the humps. The consequence is that they risk pulling right into you or, at least, braking hard right in front of you.

Bloody awful things.
Treacodactyl

tawny owl wrote:
But not speed bumps - they're inefficient and dangerous in themselves, particularly when many councils ignore the rules about what height and length they're supposed to be.


IIRC some councils are removing speed bumps due to the problems they cause. They can cause more pollution due to people slowing and speeding up all the time and are one of the reasons people give for driving 4x4s around in towns. 4x4s certainly cope much better with speed bumps and all the potholes that never seem to get filled.
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