Slashdot Mirror
The World's Fastest Electric Car
Roland Piquepaille writes "In this review, Forbes.com looks at the fastest electric vehicle in the world, the tzero roadster built by AC Propulsion Inc. 'The tzero does 0 to 60 mph in 3.6 seconds, according to the company, and it does it on only 200 horsepower.' The company says it starts faster than a Ferrari F355. It also has a limited range of 280 to 300 miles at 60 mph on a single charge. The company expects a price somewhere between a Porsche and a Ferrari, but Forbes says it carries a $220,000 sticker price. This overview contains more details and links. It also includes a rendering of the Tzero. Please note that the Forbes article has a very different focus from the one mentioned in a previous Slashdot reference."
It also only has an 80 mile range...
Power plants are incredibly more efficient at producing electricity than your car engine.
What?
Rather than being 'design to fail' after the warranty expires; it is more likely that they are designed for their own purposes. Then rigorous testing will show the average time that the item will fail, and the warranty date is set to a time after that point at which they can still afford to have a warranty and not be losing money.
The phrase "Designed to fail after the warranty expires" is misleading. The warranty date is set after the product is designed, built, and tested.
What?
If you read the article you would know that the range of 100 miles was the range of the vehicle with some older battery. With a 'new li-ion' one, the range was increased to 280 to 300 miles.
The substantial storage capacity of electric car battery packs would also give benefits for the electrical grid (which should be high on our list of priorities after 8/14/2003). See the papers at acpropulsion.com about vehicle-to-grid ancillary services.
And no, I have no relationship with these guys, I just think they're clever and have a damned good idea.
Scientists restrict study to entire physical universe; creationist
The most important fact here is that most powerplants are not emitting their pollution directly onto crowded downtown streets.
Whether they emit more pollution en masse than vehicles do is irrelevant, as those are not normalized statistics. Electricity is used for just about everything these days, but combustion engines are used for transportation and very little else. Is it really any wonder that power plants generate more pollution? They're providing much more power overall, even despite transmission line losses (which are quite low, compared to the inefficiency of a typical gasoline combustion engine).
If you could take away 33% of the CO2 emissions (vehicles) and add back maybe 10% of that by adding new power plants, does that sound like a good deal to you? They're more efficient, it really is that simple.
Random and weird software I've written.
3000$ was the number that thay were quoting for the lead-acid.
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"Put 100 megawatts of power into a transmission grid and I doubt much more than 50 or 60 megawatts come out the other end."
False. Modern transmission systems can achieve under 2% loss in large-scale power transmission. And that's talking about a scale of Terawatts Hours, not Megawatts (keeping in mind that as the amount of energy lost in transmission is proportional to the amount of energy transmitted). Granted the site is for the UK power grid, but it shows you that any modern transmission system is ridiculously unlikely to be operating at 50% loss on a megawatt scale, even when dealing with distribution levels (transmission refers generally to connected substations, etc. on the power grid, distribution refers to how it gets to your house from there).
--- What
Learn about torque. Electric motors generate tons of it at any speed. Gas engines don't. Most people havent a clue what horsepower actually is. these days its a well abused marketing term. Sort of like claiming mhz in a computer processor defines how fast it computes.
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IMO, I think this vehicle is overpriced. Most electric motors will out-accelerate equivalent gas-powered ones. Here are some links to other fun electric vehicles that the common man can actually afford:
An electric crotch-rocket style motorcycle for $6800 at Electric Motorsport
An electric dirt-bike for $4699 at Electric moto
My buddy turned on his Honda hybrid for me yesterday and it said he had been getting 65 mpg. That was in LA traffic.
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200hp is more hp than my turbo-charged internal combustion engine car. My car has a speed limiter on it set to 220kph, but it can certainly go faster if that's removed. 200hp is a lot, even if it seems miserly in these days 500+hp.
The problem is that your basic assumptions about gas engines are completely incorrect. From a consistent work/power aspect they are quite shit. Take a look at this dyno graph:
Ferrari 360
The line with the hump in the middle is the torque, the line that goes mostly from bottom left to top right is the horsepower. You'll notice that at idle, the Ferrari makes about 60 horsepower. Not much, huh?
The beauty of electric motors is that they have a constant power output at any speed. If this electric car were tested on the dyno, the graph would be a FLAT LINE at 200HP. The electric car's secret is that it's able to gain speed very early (before the gas engine has time to realise it needs to start working).
Your MR2's peak power output would be the electric car's *constant* power output, even at zero rpms when launching.
Actually, it would probably be more practical to put the motors where traditionally the differentials would go, and embed the planetary gear set in the motor itself. This allows two motors and a lightweight suspension.
Healthcare article at Kuro5hin
Regenerative braking doesn't recover all the energy. I apologise for not making that more obvious. The wastage due to friction {an absolute, not a percentage} is directly proportional to mass -- so heavier vehicles are less efficient.
I think you are also being quite pessimistic about the efficiency of internal combustion engines. With proper engine management and continuously-variable transmission systems, engines are much more efficient today than they used to be. An ordinary car has only five gear ratios, so the engine speed has to vary greatly to cover a range of road speeds. An engine driving the wheels through a CVT keeps constant revs except during acceleration. As long as you press hard on the gas pedal, the engine speeds up; when you relax your foot, the engine starts slowing down and the transmission adjusts to make up the road speed. When you press the brake, the transmission adjusts to match the road speed to the still-slowing-down engine, so it will be ready to drive again when required. When maintaining any constant speed, the engine maintains the same constant revs. The transmission ratio is adjusted so gradually that a clutch is only needed when the vehicle is coming to rest. Modern electromagnetic clutches are better than centrifugal clutches, because they disengage more positively.
Better-refined fuels - which would almost certainly become the norm anyway with the adoption of biomass-derived replacements for petroleum - and leaner fuel-air ratios would eliminate the need for catalytic converters {themselves a bodge, sacrificing fuel efficiency for slightly cleaner emissions} as the products would consist of just carbon dioxide and water vapour, and no unburned fuel. The exhaust products would still carry away kinetic energy, but some of this could be recovered with a turbocharger. With the engine doing near-constant revs, the turbo could be active almost full time - achieving an efficiency close to the theoretical maximum.
I've no problem with the idea of electric vehicles per se {and modern electronic control systems have the same benefits as CVT}; I just don't think lugging a heavy battery around is the best way to do it. But for public transport systems powered by means of overhead wires, electricity certainly has advantages.
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