Tesla finishes development of new drivetrain, ready to start building real cars
It looks like the wait might soon be over for aspiring Tesla Roadster owners as the company has just announced that it has completed validation of the upgraded drivetrain 1.5. Tesla has so far delivered 27 cars to customers with the interim drivetrain and another 23 cars are in progress. According to Tesla SVP Darryl Siry, 11 more cars will have the interim drivetrains installed for initial delivery. From that point on, within the next 2-3 weeks, the company will start installing the new drivetrains - including the upgraded motor, power electronics and single speed gearbox. For production, veteran transmission manufacturer BorgWarner will build the gearboxes for Tesla. Over the last several months, Tesla has been testing cars with the same transmission design manufactured both by BorgWarner and in-house at Tesla but ultimately chose BorgWarner.
Now that the powertrain is ready, Tesla will ramp production starts from four cars per week to ten per week. By next March, Tesla hopes to be up to 40 cars per week. The upgrades mean the Roadster's motor now goes from 211 to 280 lb-ft of torque, while the range also increases by ten percent to 244 miles. Over the coming months, the 38 cars that are delivered with interim powertrains will also be retrofitted with the new hardware. Sounds like it's time for another Tesla Roadster drive.
[Source: Tesla Motors]
Tesla Motors Selects BorgWarner for Production of New Gearbox for Tesla Roadster
Deliveries of 27 Roadsters Completed to Date, Production and Delivery of Roadsters To Accelerate With Final Powertrain Solution
SAN CARLOS, Calif.--(BUSINESS WIRE)--Tesla Motors Inc. has selected BorgWarner Inc. for the production of a single-speed gearbox for the Tesla Roadster and is initiating a ramped-up production rate. So far, 27 customers have taken delivery of Roadsters.
Tesla engineers developed the specifications for the new gearbox and provided them to BorgWarner. The new gearbox is an integral part of an enhanced powertrain with significant performance and efficiency improvements. The new powertrain delivers about 30% higher motor torque on a single gear ratio, and it achieves a 10% higher EPA combined range.
"Last December, when the two-speed transmission designed by a previous supplier proved not to be durable, we announced we would modify our approach," said JB Straubel, Chief Technology Officer of Tesla Motors. "By using a more powerful inverter and an enhanced motor design, we were able to implement a single-speed gearbox and still achieve our original performance goals. In fact, the new setup is superior in almost every way."
The new gearbox is designed for the higher peak torque levels of the new Roadster powertrain, which has increased from 286 Newton-meters (211 foot-pounds) to 380 Newton-meters (280 foot-pounds). The new powertrain achieves an EPA combined range of 244 miles on a single charge, up from Tesla's previously announced EPA range of 221 miles.
Production of Tesla Roadsters began in March, and the first vehicles were built with an interim transmission design. Customers who own Roadsters with the interim transmission can have their powertrain upgraded free of charge.
Tesla Motors starts production of 10 new Roadsters each week. Customers typically take delivery four to six weeks after production begins. The company expects production starts to ramp up to at least 20 vehicles per week within a few months and 40 per week by early 2009.
"Successfully implementing the new gearbox in less than a year was an incredible technical challenge and huge accomplishment for Tesla's engineers," said Ze'ev Drori, Chief Executive Officer of Tesla Motors. "Now that we have a final powertrain design, in a matter of months there will be hundreds of Tesla Roadsters across the country. We're heralding nothing less than a new era of the automobile."
About Tesla Motors
Tesla Motors develops and manufactures electric vehicles with exceptional design, performance and efficiency, while conforming to all U.S. safety, environmental and durability standards. The Tesla Roadster is the only highway-capable production electric car of any kind for sale in the United States. With a 0 to 60 mph acceleration of 3.9 seconds, a 14,000 rpm redline, and the fastest top gear acceleration of any production car tested by Car & Driver magazine in 2007, the Tesla Roadster is unique in providing super car performance, zero emissions and extraordinary efficiency. For more information, visit www.teslamotors.com.
Reader Comments (Page 1 of 1)
Serge 5:56PM (9/09/2008)
Looks like TM is on track with power-train 1.5 implementation. This is the first mention I've seen of range increasing by 23 miles. It will be interesting to see what the real-world results (as tested by Martin Eberhard) look like. Exciting ...
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Gordio 7:33PM (9/09/2008)
Why don't they put more than two gears? Doesn't more overdrive = more distance? especially if peak torque is at zero rpm.
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Jameson 8:15PM (9/09/2008)
Because electric motors don't have the same internal friction losses at higher RPMs as piston engines so they can afford to have it spin quite fast on the highway. With an electric motor you only have the rotor spinning in free air and a few bearings vs. the piston rings, crank bearings and valvetrain of a normal engine. As you can see by the 10% range increase it's actually more efficient to have a single speed than a two speed.
Chris M 9:19PM (9/09/2008)
IC engines can only operate over a modest range of speeds, and their peak efficiency is in a relatively narrow speed band. For them, multiple gears are essential and overdrive makes sense.
Electric motors operate over a very wide range of speeds, and their peak efficiency also covers a wide speed range. The first Tesla Roadster used a 2 speed transmission just to get a blazing 0 to 60 time (first gear) and a reasonable 120 mph top speed (2nd gear), but the transmission simply couldn't handle the massive torque and failed too soon, as did another 2 speed transmission model they tried. A multispeed transmission wouldn't have offered any benefit, would have added weight and cost, and probably wouldn't have lasted any longer than the two speed units.
With improvements to the motor controller, a two speed transmission wasn't needed, and a simpler and much sturdier fixed gear unit is used instead. Note that the "fuel economy" actually increased slightly, as the single speed is lighter and has fewer moving parts.
Andy 9:43PM (9/09/2008)
That's interesting information.
The UK based lightning car is planning to use direct drive wheel hub motors. I seem to remember their claimed miles per KWh (from the battery pack spec') is better than Tesla. With a heavier car.
I'm wondering if their motor and drivetrain configuration is more efficient or can they claim more available Ah from the altair pack?
Of course Lightning have not actually demonstrated anything yet. Too bad they are not as open as Tesla (hat tip) in the development process.
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GoodCheer 10:15AM (9/10/2008)
"their claimed miles per KWh is better than Tesla.
(....) or can they claim more available Ah from the altair pack?"
A kWh is an amount of energy, an Ah (at a given pack voltage) is also an amount of energy. Getting more Ah from a pack would not change the miles per kWh, it would only change the miles per charge.
You question is a bit like asking if you can get more mpg by getting a bigger gas tank.
If they get more miles per kWh, it can only be from greater efficiency, be that in the drive train, aerodynamics, or domestic loads.
Mulad 10:43PM (9/09/2008)
I've just been wondering if they'll get the Tesla to show up on the EPA's fueleconomy.gov site once they ramp up to full production with the finalized drivetrain. I suppose the company's production may remain too low to get listed, though.
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jake 11:04PM (9/09/2008)
At peak production, Tesla plans around 2000 Roadsters per year, so they'll probably be too low in production to be listed (I'm not sure if the EPA has a production limit for listing though). Probably when Tesla makes their Model S then they'll get on the list for sure, with 20,000 units per year.
But this is good news for Tesla, since they are on time because they promised the 1.5 drivetrain will be ready by car #40 in September. The range increase also makes it nearer to the 250 miles that they originally targeted years ago when it was first introduced.
BlackbirdHighway 5:37AM (9/10/2008)
I had contacted the EPA about the fueleconomy.gov site some time ago to ask them why they didn't list the Tesla Roadster.
They replied that it was up to Tesla to send them the information and give them permission to add it, and Tesla hadn't done that.
From the EPA: "It is my understandings that the Tesla Roadster has been certified by the EPA, however, it is up to Tesla to decide when to release the estimates to the public if they intend to release them before the car arrives in showrooms."
I assumed that Tesla wanted to wait because the range/mileage would change slightly with the new drivetrain. Tesla has already had to change their range number several times, with some loss of credibility, so I'm sure they wanted to wait until they had the final numbers.
Now it seems the new drivetrain is finished and higher production numbers are being ramped up, so maybe Tesla will finally post it up on fueleconomy.gov.
TEG 3:15PM (9/11/2008)
This is fantastic news that the new drivetrain passed all their tests and is ready for production. After so many false starts with their earlier transmissions, it is great to finally have this dealt with.
Performance is better, range is better, drivability is better, win-win-win.
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