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Tesla Motors Is Delivering Cars
jamie found the news that Tesla Motors is delivering roadsters in California. (We've been following developments on the Tesla front for a couple of years now.) According to a letter from the CEO, "9 production Roadsters have arrived in California, another 3 arrive this weekend, and they will keep arriving at the rate of 4 per week... In fact, currently there are 27 Roadsters in various stages of assembly." The early owners must be proud, but there could be complications.
Erm, the title has an error.
America, Home of the Brave.
Gearboxes are really for converting torque to rotation. IC engines have limited rpm ranges and "optimal" torque and power rpm bands. The gearbox is there to allow effficient use of these zones.
Electric motors have a very flat torque curve all along the rpm range (torque starts right after 0 rpm). Also Electric engines usually have a much wider rpm range and their efficiency in converting energy to mechanical energy is much more constant tha for IC engines where the efficiency drops very quickly when you approach max rpm. Hence a gearbox is only so useful for an electric car.
Mind you as well that electric motors have bags ans bags more of torque than IC engines and as such a reduction gear is not really necessary to get teh car in motion (as with a 1st gear in a regular car). This high torque is also a challenge for designers as traiditional design gearboxes flop with electric engines.
Hope that helps you understand why there are only 2 gears on this car.
Artificial intelligence is no match for natural stupidity
It looks like the thing that has largely fixed the EV issue is the laptop computer/mobile phone - which has justified the research effort into lithium batteries.
From a volume point of view in the short term the manufacturer to watch is Mitsubishi: they have a joint venture factory with Yuasa, and last week they delivered a test sample EV to a Japanese police force (they already have them with Tokyo utilities.) The Miev may not be as large and fast as the Tesla, but it is likely actually to be affordable. $100000 will only appeal to the rich who want a status symbol, as the payback compared to (say) a Mercedes Bluemotion clean Diesel will be forever. But a $30000 commuter vehicle may well make economic sense. I could justify one right now if oil reaches $200/barrel.
In fact, there are reports that sales of the EVs currently available are very poor, presumably because people who might have bought one as a third car are spending the money on new, efficient vehicles which will show a real cost saving in a sensible payback period.
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."
Actually I was wondering why it doesn't have just the one ratio. I assume the reason was to get a nice high maximum speed, ie, the top gear is an overdrive.
Yep. And they've decided to scrap it in favour of a single speed, slightly higher ratio gearbox on newer models, also. I think they'll start delivering those in about 6 months or so, from what I read on their blog.
(torque starts right after 0 rpm)
Close, but the torque starts right at 0 rpm. Actually for most electric motors, the torque peaks at 0 rpm. Thats why there's no need to "idle" the electric motor when the vehicle is stopped, and also why there is no "torque convertor" as in automatic transmission equipped IC engines.
Besides, if there was no torque at 0 rpm, then it would never begin to move...
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
Close, but not quite. I don't exactly remember why the curve looks like that, something do to with inductive reactance.
Those are AC motors.
Here's some info on DC motors. (Note the curves are theoretical, and simplified).
http://lancet.mit.edu/motors/motors3.html
Torque is max at 0 RPM.
TANSTAAFL GIGO Acronyms to live by!
Carbon fiber is itchy as hell when it fractures, but it isn't hazardous. I'm an engineer with a Plastics/Elastics manufacturing firm. One of our materials is a wound carbon fiber / PEEK composite. Our machinists cut it on a lathe, and it gets everywhere. Just itchy, though.
Prove it. Find 5 patents that are owned by "Big Oil". Also, define "Big Oil".
Okay, Big Oil should be pretty easy. From this wikipedia page, you'll get ExxonMobile, Royal Dutch Shell, BP, Chevron, ConocoPhillips, and Total S.A. And they don't register these patents under their own names- they use subsidiaries. For example, Chevron owns Cobasys, a NiMH battery maker.
5 Patents? Hell, I can find you at least 40.
Do I get a cookie?
Sigs are for losers
I can give you 125 examples.
According to Wikipedia, Cobasys and ECD Ovonics hold 125 patents for battery technology, particularly NiMH battery technology. They produced the batteries that powered the ill fated EV1. In 2001, Texaco (now Chevron) bought Cobasys. Since then, they have refused to sell automotive batteries or license the technology to smaller players. Since the big players were not interested in electric cars (perhaps because of influence from Big Oil), this effectively killed electric cars.
They have also actively used their patents to prevent others from selling NiMH batteries for automotive purposes in the US. In 2001, same year as they were bought by Texaco, they sued Panasonic EV Energy for patent infringement. The results were that Panasonic is restricted from selling commercial quantities of some batteries in the North American market until 2010.
cant name 5 patents but I CAN name one very important one. Try making and selling Nickel Metal Hydride batteries suitable for electric cars and see how far you get.
You mean like the large-format NiMHs in the Vectrix scooters?
You will likely be sued by a company you haven't heard of called Cobasys for violation of their patent on NiMH battery tech.
Cobasys has repeatedly made it clear that they will deal in large orders for large format NiMH, but not small orders. There haven't exactly been people lining up around the block wanting large orders of large-format NiMHs, however. It's old tech, inferior in about a dozen different ways to the modern automotive li-ions.
FYI, Cobasys only holds the patent rights on said large format NiMHs in the US, not internationally. Oh, and they've cross-licensed their patent portfolios with PEVE (who they initially sued for making NiMHs for sale in the US without paying them); PEVE now has the right to make large format NiMHs for sale in the US. The fact that they haven't should speak volumes for the demand of said batteries.
NiMH was top of the line tech back during the original CARB ZEV mandate. It no longer is.
No, she's fine. My associate is vomiting for a totally unrelated reason.
The Tesla Roadster shuts itself down when the battery is "empty". Of course, it's not really empty, it just disables itself to prevent permanent damage to the battery system.