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fostertom
Net Member
United Kingdom
505 Posts |
 Posted - 05 Mar 2010 : 08:14:58
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From http://www.bdonline.co.uk/story.asp?storycode=3159328&origin=BDweeklydigest
Putting the planet in the driving seat
05 March 2010
The gasoline-powered private automobile is like a geriatric rock star. It has been with us for more than a hundred years. In its youth it served as a powerful icon of modernity and personal freedom (it still has its Top Gear groupies) but those days are long gone.
Now, its obnoxious downsides far outweigh any pleasure that it continues to give. And it has never managed to kick a really nasty hydrocarbon habit.
A typical modern automobile can attain speeds of more than a 100mph, but average urban traffic speeds rarely exceed 20mph. It has a range of about 300 miles, but most urban drivers log fewer than 25 miles per day. It weighs about 20 times as much as its driver and for around 80% of the time it sits doing nothing useful apart from consuming scarce urban real estate, costing money and embodying energy and materials that could be put to better use. It is ridiculously over-engineered and over-priced for the role of providing personal urban mobility.
Fortunately, the convergence of relevant technologies now enables the development of a fundamentally different type of vehicle for this purpose — the lightweight, intelligent battery-electric automobile (it is almost always the convergence of emerging technologies, rather than a single technological breakthrough, that opens the way for disruptive new products). Battery technology is not yet everything we would like it to be, but the latest lithium-ion batteries are good enough to put battery-electric vehicles over the threshold of feasibility.
Compact, inexpensive, high-performance electric motors and power electronics enable vehicles with digitally controlled motors in the wheels, rather than a central motor and traditional power train, which provides more space inside on the same footprint.
Electronics and software can replace mechanical controls — transforming automobiles into smart, wirelessly interconnected robots on wheels.
My colleagues and I, working at MIT and General Motors, have recently been able to demonstrate the possibility of a 1,000lb automobile based on these principles, as compared to about 3,000lb for a Prius or 4,000lb for a typical SUV. When parked, they are less than 100 inches long and should do better than 200 miles per gallon.
We can expect to realise major energy and carbon benefits— for example, from the optimised integration of electric charging infrastructure with smart grids and clean, renewable power sources.
The technological barriers to implementation of clean, sustainable, personal urban mobility systems are falling fast. It is now mostly a matter of political will, design and policy imagination, and resourceful pursuit of new business models and opportunities.
It is a strategic moment. If we can effectively grasp it, we can begin designing automobiles to satisfy the needs of cities rather than cities to meet the requirements of automobiles.
Postscript :
Reinventing the Automobile by William J Mitchell, Christopher E Borroni-Bird, and Lawrence D Burns, is published this month by MIT Press.
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julian
Forum Admin
United Kingdom
2834 Posts |
Posted - 05 Mar 2010 : 09:26:28
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Typical twoddle
A car does what it needs to do - top speed might be 100mph but that is a side effect of being able to cruise at legal speeds comfortably and economically. If you could guarantee 100% that a given car would never leave the urban environment then by all means give it a top speed of 40mph but keep in mind that it could never go on a motorway as a result. If for *any* reason it has to go further than 30 miles in a single trip you need a bigger fuel tank - just in case, if you want to go long distance then you need the redundant capacity to do those distances. If you are going to be the only in the car, ever, then by all means give it just a single seat but if for any reason you want to carry your family then you need the 4/5/7 seat arrangements that are common to most cars, if you need luggage space for any reason then you will need the carrying capacity.
This isn't just about making it fun - this is about practicality. The smart car may have been (relatively speaking) a commercial success but it is still a fundamentally flawed vehicle outside of its native environment which means most owners need 2 cars - the smart car for day-to-day and something bigger for everything else (like doing the weekly shopping).
The ideas that the authors are spouting are good and to a large degree correct but typical of academia they have no place in the real world - or at least no place outside of north american cities.
The real practicalities remain - not least of all how to get an electric vehicle with a range of 50 miles to refuel in a meaningful period of time for when you need to do more than 50 miles.
Attempts at making such vehicles fun are still struggling although the big "supercar" manufacturers are now dipping their toes in the water - Ferrari with their KERS for the common people and Porsche with hybrid electric. It has taken the best part of 20 years for such things to become properly viable for domestic vehicles though.
Attempts at truely wireless control systems are likewise limited, nice idea in principle but the failsafes are sorely lacking, even the throttle-by-wire systems in cars now are limited and require some re-education of the driver. Toe-and-heel? No - doesn't work. Left foot brake? No - can't do it. Why? because the only way that a throttle-by-wire system is allowed on the roads is if the throttle closes whenever the brakes are used. Ever wonder why so many Clio V6s ended up in ditches - yep you guessed it, even the most experienced of drivers were caught short coupled with a lively short wheelbase. So what are they going to do for wireless steering and brakes? What happens when the ECU gets the automotive equivalent of a blue-screen-of-death? On planes it means multiple redundant control systems but such things are practically unheard of in cars.
And what about that 1,000lb automobile? The likes of the old cinq and sei weren't far off, managed to provide seating for 5 (at a squish) so it isn't a particularly long shot. 100 inches long isn't far off either, in fact that pretty much describes the entirety of the older supermini concept (they seem to be getting bigger now), so what we're really talking about here is introducing overweight americans to the concept of microcars which they have steadfastly rejected for as long as the car has been around.
Someone go out, find messrs Mitchell, Borroni-Bird and Burns and give them a force-fed education in automotive history, preferably using a lump of clue-by-four |
1998 Seicento 600M - extreme version
2000 Ford Explorer LPG'd up but well and truely f****d
1978 Replica Icsunonove w/Uno Turbo power (250bhp+ and 600kg)
2009 Abarth 500 |
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fostertom
Net Member
United Kingdom
505 Posts |
Posted - 05 Mar 2010 : 13:44:09
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V gd julian - esp the bit about 'what we're really talking about here is introducing overweight americans to the concept of microcars'. I'll feed some of that back into BD any-answers where it came from.
In an electric car, what would non-fly-by-wire throttle and (regenerative electric) brake look like? |
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julian
Forum Admin
United Kingdom
2834 Posts |
Posted - 06 Mar 2010 : 03:55:26
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The current technology does not allow for pure regenerative braking, the systems we have at the moment still require conventional brakes as well but on top of that what would happen if the regen-brakes fail due to electrical fault? You still need some level of mechanical/friction braking to ensure that the car is capable of stopping and to do that you must have mechanical/hydraulic backup - in fact current legislation states that you must have a mechanical handbrake to cover for failure of the hydraulics and for good reason. True the hydarulics are generally more reliable than the mechanical backup and it is typically the handbrake that fails roadworthyness tests, not the hydraulics but the point remains.
The electronic throttle control is already established, it is the steering that really worries me - I've seen some of the concepts and proposals. First of all I'm really rather attached to the concept of the steering wheel, it offers progression, balance, finess and ease-of-control in one very simple mechanism. The idea of joysticks in cars (outside of passenger entertainment systems) is crude to say the least and ignores much of the problems such things can present (anyone familiar with a joystick knows what I am talking about). The american military went through all of this decades ago when they stuck a pure electric control system in the F16 - they got it to work in the end but even today the pilots gripe about it in between blessing the plane for its agility - but that is a plane, not a car. You don't tend to find military jet pilots half dozing at the wheel, gesticulating at drivers or retuning their stereo - not forgetting the rigorous maintenance schedule such planes have to go through to remain airworthy. Even assuming you don't go down the joystick route and stick with a steering wheel you still have the problem of what to do when things go wrong, where are the mechanical backups that allow you to retain at least a level of steering control in the event of primary control system failure? Sure we have power assisted steering and on some cars it is practically impossible to steer without the power assistance (you wouldn't want to do much with my explorer without it) and the same applies to brakes - failure of these systems are not a happy place to be when you get caught out but equally the systems still work you just have to be brutal with them. Failure of an electrical control system is potentially catestrophic.
The irony is I would welcome the innovation and freedom but from an engineering point of view and a safety perspective I cannot put any kind of support behind such ideas. They are pipe dreams and little more. |
1998 Seicento 600M - extreme version
2000 Ford Explorer LPG'd up but well and truely f****d
1978 Replica Icsunonove w/Uno Turbo power (250bhp+ and 600kg)
2009 Abarth 500 |
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sumplug
Moderator
United Kingdom
5112 Posts |
Posted - 06 Mar 2010 : 08:26:16
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Lets just correct what he said in that article. Zero emission Internal combustion cars are already with us. Saab for example has on its American models, a closed loop exhaust system that produces nothing but H2o.
Batteries have a certain life, What will the cost be to an owner and the enviroment to replace these batteries? The green movement, never mention these issues, but dead batteries need to be disposed of..
What are battery powered cars like fully loaded up? I bet they soon use up their power supply!! And the time it takes to recharge. 16+ hours.! Not exactly 'friendly user' is it? Then bring in the cost factor to buy a decent battery car, and then the £96000 for a Tesla smacks you right in the mouth!!
Andy. |
Fiat Coupe 20vt
Audi A6 Avant 4.2 Sport LPG
??? Wait and see!!
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julian
Forum Admin
United Kingdom
2834 Posts |
Posted - 06 Mar 2010 : 12:36:05
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The lithium based batteries that are the current favourite are certainly not what you'd call green but are far better than the old nickel-cadmium based affairs and way, way better than wet cell batteries with lead acid in them. The upside is that they are much less toxic, fully recyclable and with proper conditioning last much, much longer than the old batteries too, not to mention the better power density and versatility of physical design. The cost is the bit that is hard to swallow but largely because at the moment supply is something of a problem, with a ramp-up in production as would be needed for large scale production of electric cars based on this technology the cost of the batteries comes down substantially.
The big point about the article that started this thread was not zero emissions, it was moving away from hydrocarbon fuel and all the forward looking technologies that go with such a move. Like I said before, as a bluesky exercise it really isn't that bad - it is the real world that gets in the way.
The largest factor though is the recharge problem - everyone recognises it for what it is (a noose around the neck of battery powered cars) and it is where a lot of effort is going into finding a solution. There is talk of standardising the battery pack so that a visit to the "petrol" station means ejecting the old pack and inserting a new fully charged one but the power density issue is still an issue compared with hydrocarbons but given most petrol stations have substantial underground tanks it isn't such a huge stretch of the imagination to see such things uprooted and replaced with underground charging stations for the packs.
There is no doubt at all that something has to be done to improve the power density further - JC and co proved this with the Tesla, it is supposed to last 200 miles but they finished it off in under 50. Admittedly said individuals are hooligans when it comes to testing cars and prone to breaking things but the results are still valid. 50 miles of foot to the floor driving in the "relatively" light Tesla was all it could manage. How you get 200 miles out of one is something of a mystery but not really different from getting the range listed in the brochure of any car. The problem isn't far different from that faced by the Vauxhall/Opel relative to the Tesla - the VX220/Speedster, it was supposed to have a similar range but any attempt at driving the car with anything other than utter reservation meant a practical range of about 60 miles, on the track you would struggle to see half that. |
1998 Seicento 600M - extreme version
2000 Ford Explorer LPG'd up but well and truely f****d
1978 Replica Icsunonove w/Uno Turbo power (250bhp+ and 600kg)
2009 Abarth 500 |
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fostertom
Net Member
United Kingdom
505 Posts |
Posted - 09 Mar 2010 : 13:51:34
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Yes I know these need proper brakes as well as regen, and I also wd deplore fly-by-wire controls - don't even like power steering. Why wd that be part of the package? when in such a lightweight even servo braking might be unnecessary. Electric cars shd be an opportunity for simplification and more, not less direct controls.
That being the case, returning to the original question, which has been diverted into grumpy 'it'll never fly' stuff - How will Fiat make this fun? Don't tell me they're not thinking about how to give electric cars that bit of Latin pizzaz. |
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julian
Forum Admin
United Kingdom
2834 Posts |
Posted - 09 Mar 2010 : 14:50:15
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The disconnection between the road and the driver is something the likes of MIT (and others) have been playing with for the last ten years. Do some digging and you'll find plenty of examples of fully virtual control systems in prototype "electric" cars. It is all part of the "package" that the dreamers are working on.
As for fun? The Tesla is a prime example of elecric cars not being boring, even if it is hugely compromised on price and some aspects of performance (handling and range in particular). We've seen electric cars in IRL over the last few years (what happened to them I have no idea) and the KERS system in F1 more than illustrates the viability of the systems even if they still need some fine tuning to make them user friendly.
For Fiat - fun means nippy performance, responsive handling and comfortable responses at cornering speeds a good 20% higher than other european countries consider necessary (probably the prime reason we enjoy small fiats so much). Just because you don't have a peaky, noisy and largely ineffectual (lots of noise and drama but not much go) petrol motor in the front doesn't really change things that much. The loss of the aural element is something that most petrolheads are dreading but it is largely inevitable, the rest though is pure Fiat. That said Fiat are paving the way for small, highly efficient combustion engines to the extent that many other manufacturers are paying Fiat for the tech under license or just buying in engines. Such designs may be prolonging the agony of withdrawal from hydrocarbon fuels but at least they are proving it can be done and are not dependent on the use of fossil fuels to do it. Much of the work has gone into using renewable hydrocarbon fuels instead so perhaps we can consider it more of a bridge then... |
1998 Seicento 600M - extreme version
2000 Ford Explorer LPG'd up but well and truely f****d
1978 Replica Icsunonove w/Uno Turbo power (250bhp+ and 600kg)
2009 Abarth 500 |
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fostertom
Net Member
United Kingdom
505 Posts |
Posted - 10 Mar 2010 : 08:35:53
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Good background info - thanks.
In particular, what will be the effect, on 'fun', of
lighter weight, particularly no heavy lump up front (but batteries under the back seats)
forward driving position due to no engine bay in front of the passengers' feet
skinnier tyres
lighter direct-mechanical controls
electric motors' max torque from zero revs
etc |
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julian
Forum Admin
United Kingdom
2834 Posts |
Posted - 10 Mar 2010 : 12:01:51
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We can take a good guess as to the effects of weight - this is extremely well understood but I think most people underestimate how heavy those batteries are - and all the electrics and heat dissipation equipment. The good news is that it is all very low down which is great for CoG and can be put in more considerate positions to achieve better weight distribution.
Eco tyres are not necessarily narrower - the results will be a trade off between grip, wear endurance and economy. Anyone who has driven a typical american family car will appreciate how rubbish the ultra hard wearing tyres they are fitted with really are and why euro/jap import tyres are so immensely popular with enthusiasts there while we struggle to really feel the difference between brands. The only thing they have in their favour is that barring punctures the tyres may well outlast the life of the car.
The one thing that has made electric motors viable for use in domestic cars has been the developments in power control. As pointed out the electric motor by itself is only really good for getting the car moving because once it is spinning the torque drops off dramatically. Power controlers have given the engineers the ability to extend the effective performance range of the motors while avoiding some of the huge power drain that otherwise results. Obviously there is gearing choice as well when you use a single big motor but the current trend is towards one motor per wheel so a gearbox just doesn't work (or fit), there is still some gearing involved but not in the conventional sense. |
1998 Seicento 600M - extreme version
2000 Ford Explorer LPG'd up but well and truely f****d
1978 Replica Icsunonove w/Uno Turbo power (250bhp+ and 600kg)
2009 Abarth 500 |
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fostertom
Net Member
United Kingdom
505 Posts |
Posted - 11 Mar 2010 : 05:23:41
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| So no real pointers then, to what electric cars will, or could (we wish) evolve into, in terms of driving fun? No guesses as to what Fiat's unique emphasis could, or should (we think) be? |
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julian
Forum Admin
United Kingdom
2834 Posts |
Posted - 11 Mar 2010 : 05:42:22
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The question is how will Fiat use the technology in small cars (forget big cars for the moment). Are we talking about super economy to achieve range? A new smaller class of vehicle (compared to the current range of Fiats)? Or are we talking about more of the same - nothing special in any particular field except relatively cheap, nippy around town and fun to drive?
Due to the battery requirements, larger cars are going to be just as heavy as they are now and suffer all the same problems, plus Fiat still haven't quite figured out what the european market wants from a large family car and no idea at all about what the americans want out of such a car. Alfa remains a relatively niche market despite the "prestige" factor, Lancia is sadly a dying brand and no-one in their right mind buys a big Fiat outside of Italy (allegedly - I can't talk as I owned a Marea and loved it). Small cars though is another matter but can Fiat keep it all within the design envelope that they know and understand? |
1998 Seicento 600M - extreme version
2000 Ford Explorer LPG'd up but well and truely f****d
1978 Replica Icsunonove w/Uno Turbo power (250bhp+ and 600kg)
2009 Abarth 500 |
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sumplug
Moderator
United Kingdom
5112 Posts |
Posted - 11 Mar 2010 : 06:33:44
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I hate talking about battery powered cars, but the way forward is fully plastic cars to make them as strong and as light as possible. Batteries with charged power and a roof panel to constantly charge the batteries. Wheeled power and maybe a small 2 cylinder engine for limp home mode, if you run out of power.
Large cars will need some sort of extra power, like an efficient small engine, plus batteries, So Keep the hybrid idea going. Works fine.
Andy. |
Fiat Coupe 20vt
Audi A6 Avant 4.2 Sport LPG
??? Wait and see!!
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fostertom
Net Member
United Kingdom
505 Posts |
Posted - 11 Mar 2010 : 08:10:32
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Andy, a PV on the roof wd be fine but nowhere near big enough to be worth it. An array at home charging the car, at least Mar-Oct, wd be a fine use in principle of PV investment - except that the new feed-in-tarrifs (FIT) make it more advantageous to sell output to the grid, than to use yourself.
How wd a limp-home IC engine work, with elect motor in ea hub so no transmission/driveshafts?
Julian, what kinds of elect car wd we like to see?
Super-economy max range might be a whole new class of car, only possible in lightened simplified elect car form. What wd it look like?
The functional equiv to the current range of small Fiats wd be not just 'more of the same', but smaller lighter and simpler, maybe not needing power-anything, not even servo brakes.
What other classes can we anticipate? What would we like?
I'm sure that SFC people can imagine a life without thy IC engine - or maybe it's really curtains? |
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julian
Forum Admin
United Kingdom
2834 Posts |
Posted - 11 Mar 2010 : 11:52:00
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The problem with "lighter" is that the likes of the seicento shell is pretty much as light as you can realistically go with current materials *and* retain the crash safety. The smart car isn't all that light (about 50kg heavier than a seicento) despite its compact dimensions and despite an incredibly rigid safety cell isn't particularly safe but still better than the aforementioned sei which predates the strict ncap tests that we rate everything by now.
Keeping in mind that we could shrink the car dimensions down a bit, hike the shell safety up and go for lightweight non-structural panels the total weight saving isn't huge. The big saving is taking the conventional IC drivetrain out but the electric drivetrain isn't going to be any lighter so realistically you aren't saving any weight at all so we have a practical plateau in terms of vehicle mass and I estimate that at between 700kg and 800kg. If you want to keep the weight down then the cab forward concept like the Smart is not the way to go - the safety cell gets too heavy and you get all sorts of new safety issues. Keeping a conventional shape allows for real crumple zones.
Of course the current range of Fiats are not that small or light, bloat has taken hold when you compare with the previous range and while it has made for a more luxurious feel it is a backward step in the respect of size and weight.
Power steering would still be there if only because it is what people are used to now, the brakes are an unknown as it depends on other systems but with an energy recovery system you effectively have assistance to the brakes in terms of what the pedal does but not a servo but where would your servo be getting a vacuum from anyway?
One of the key factors in the "electric car of the future" is the co-operative train where 2 or more cars hitch together to assist in power delivery and aerodynamics - at least that is what the dreamers keep coming back to. I've no idea how this would work but it might considerably help with long range economy but it means an all or nothing approach as a mix of old and new technology on the roads could prove near impossible to accomodate. The safety aspect of this scares me somewhat and perhaps more importantly I can see the day when travelling on the motorway means sacrificing control of your car to an AI in order to achieve the required level of safety and traffic flow control that would be needed. |
1998 Seicento 600M - extreme version
2000 Ford Explorer LPG'd up but well and truely f****d
1978 Replica Icsunonove w/Uno Turbo power (250bhp+ and 600kg)
2009 Abarth 500 |
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fostertom
Net Member
United Kingdom
505 Posts |
Posted - 12 Mar 2010 : 04:24:07
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Good stuff.
Are we saying that elect motor/regen brake in ea hub+batteries+electronics is as heavy as engine+transmission+driveshafts+tankfull of petrol, so no weight saving? is there hope of yet lighter batteries, or more energy-density per battery?
Perhaps the batteries shd go in what used to be the engine bay, for long nose+impact-absorbtion mass.
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How will Fiat make this fun?
