I'm a big fan of "German engineering"--that combined focus on power and precision that distinguishes the better automobiles designed or manufactured in Germany.
At Frankfurt's International Motor Show, BMW will be showing off two new hybrid cars intended to deliver the full promise of German engineering. This is no small thing because most hybrid cars to date have been lightly built and somewhat underpowered in order to improve fuel economy.
The two new BMWs are more like previous offerings from that company: big, solid cars with lots of power to maintain performance in spite of the weight. They're also real cars, not just prototypes.
Fortunately, I don't need to describe these new cars here; there's a great article by Antuan Goodwin over on CNET's Car Tech blog that does a fine job of that (see "BMW unveiling two big hybrid models at Frankfurt"). What I would like to do instead is to drill down into their respective powertrains, which represent two different solutions to high-performance hybrid design, using images provided by BMW.
The ActiveHybrid X6, due to go on sale in the U.S. later this year, represents one end of the spectrum: higher-power electric motors and a larger battery pack. As the first image shows, the new X6 model has a twin-turbo V8 gas engine with 400 horsepower. Though this is a reasonably efficient engine for its size, it certainly wasn't chosen primarily for its fuel economy.
BMW's ActiveHybrid X6 uses a large NiMH battery pack and a new transmission with two integrated electric motors to augment its 400-horsepower gasoline engine.
(Credit: BMW)The large NiMH (nickel metal hydride) battery pack is also visible in this view, mounted above the rear drivetrain components and below the floor of the luggage compartment. This battery pack holds 2.4 kWh (kilowatt-hours) of energy; BMW also specifies a "nominal" 1.4 kWh figure, but doesn't explain the difference between total capacity and nominal capacity. I suspect the difference may be related to improving battery lifespan, or perhaps provide some extra storage to ensure that electric braking assist (regenerative braking) is always available. BMW does say that this braking mode can generate as much as 50 kilowatts of power and 0.3 g of deceleration force.
In the following view of the X6's transmission, the electric motors are shown built right into a new transmission that BMW describes as an "electric continuously variable transmission"--the electric motors and three planetary gearsets work together to provide the equivalent of seven gear ratios.
The transmission in the ActiveHybrid X6 has two integrated electric motors totalling 177 horsepower.
(Credit: BMW)Interestingly, with ratings of 91 and 86 horsepower respectively, the two electric motors could provide a total of 177 horsepower, but the vehicle isn't designed to operate that way. BMW specifies a maximum system output for the ActiveHybrid X6 of 480 horsepower, reflecting a maximum contribution from the electric motors of around 80 horsepower.
Part of the issue here is that the battery pack is rated at a maximum output of 57 kW, roughly 76 horsepower, so there isn't enough electrical power to drive both motors at full power. I expect there are also some issues related to heat and torque, but BMW hasn't offered a full explanation of this limitation.
It's also interesting to note that while the new X6 supports a pure electric drive operating mode, it's only good up to 37 mph and 1.6 miles. This figure is well below the energy capacity of the battery pack, probably reflecting more limitations imposed in the name of long-term reliability.
The ActiveHybrid 7, a hybrid version of BMW's 7-series luxury sedan due out in the spring of 2010, takes a very different approach. It has only a small electric motor positioned between the engine and transmission, and it comes with only a small lithium-ion battery pack. The following figure shows that the battery pack is located to the side of the trunk, leaving plenty of space for golf bags. (BMW says that four standard bags will still fit, which I suppose is a critical specification for 7-series customers.)
The ActiveHybrid 7 is powered by a 440-horsepower gasoline engine and a small 20-horsepower electric motor with a lithium-ion battery pack.
(Credit: BMW)Zooming into the transmission in the following picture, we can see the pancake-style electric motor in front of what appears to be a fairly conventional 8-speed automatic transmission. In its press release, BMW does emphasize that this is a new transmission design "specifically tailored to the demands of hybrid technology," but the release doesn't explain how this gearbox differs from the 8-speed automatics on previous BMW cars.
The ActiveHybrid 7's electric motor is tucked away between the gas engine and a conventional 8-speed automatic transmission.
(Credit: BMW)The new 7's electric motor produces a mere 15 kilowatts, roughly 20 horsepower. Together with the gas engine, the vehicle's maximum output is rated at 455 horsepower. The electric motor also functions as a starter motor for the gas engine and a generator to charge the two batteries on the car: a conventional 12V lead-acid battery and the 120V lithium-ion pack in the trunk.
The latter is a small pack storing only 400 watt-hours of energy--that's about like eight average laptop batteries. BMW doesn't mention whether the new 7 can run solely on the electric motor, but I doubt it; 20 horsepower probably isn't enough for that. Certainly the range would be negligible given the low battery capacity.
Instead, BMW describes the value of the electric motor in terms of two uses: first, it's powerful enough to restart the gas engine almost instantly (in less than one rotation of the crankshaft) so the engine can be shut down at stoplights, just as the Toyota Prius does. Second, the electric motor provides supplemental power while the gas engine is running, thus improving overall fuel efficiency. Since the battery can be charged by recovering braking energy, the power from the electric motor is often free.
BMW says the hybrid systems in the ActiveHybrid 7 were developed jointly with Daimler, maker of Mercedes automobiles. This partnership also led to some Mercedes models, and indeed, Mercedes has also introduced hybrids with powertrains similar to that of the ActiveHybrid X6. (Mercedes is announcing a new S500 hybrid in Frankfurt but didn't provide such nice pictures, so I didn't include it in this post.)
Both of these approaches will need to be developed substantially before they can reduce the total cost of owning and operating a motor vehicle. But it's clear that BMW, having waited this long to get into the hybrid car business, is giving its customers two very different choices. What the company does in the future will probably depend on how its customers respond.
German automotive giant Daimler has invested in electric-car company Tesla Motors and plans to use Tesla's battery packs in its Smart electric car due later this year.
At a Tuesday press conference held at the Daimler museum in Stuttgart, Germany, Tesla CEO Elon Musk and Daimler management board member Thomas Weber said the contract between the two companies calls for joint collaboration on the Smart electric car and future models.
Daimler has invested a "double-digit million-dollar sum" to acquire about a 10 percent stake in California-based Tesla, Weber said.
An electric Smart car being tested in Berlin as part of an electric-car trial.
(Credit: Daimler)"We are about to combine the best of the old and new school," Weber said during a press conference, which was Webcast. "We are both deeply convinced that electric powertrains will play a major role in sustainability mobility."
The two companies last year announced that Tesla would supply the lithium ion battery for the Electric Smart EV, a small town car. Telsa designs and makes the packs using battery cells used in consumer electronics.
Daimler plans to test those cars this year and to mass-produce the Electric Smart EV in 2012, Weber said.
The company, which has been working on electric-vehicle technology since the 1970s, chose to partner and invest in Tesla to help Daimler bring cars to market quickly, Weber added. "The first priority was to find the quickest and most straightforward solution," he said.
The technical collaboration calls for Tesla to supply battery packs and electric powertrain, and for Daimler to offer auto manufacturing and design expertise in a range of areas, such as safety and mass production, Musk said during the press conference.
"We look forward to future areas (of collaboration)," Musk said. "Smart is just the beginning."
(Credit:
Daimler)
Looking ahead to the future, the trainees of Daimler AG at the Sindelfingen Mercedes-Benz plant have built a Roadster with fuel cell drive, the company announced today.
For about a year, more than 150 trainees and dual education system students worked on the overall concept, development, assembly, and completion of the F-Cell Roadster. This project involved junior employees from the fields of automotive mechatronics, model building, electronics, coating technology, manufacturing mechanics, product design, and interior appointments. The project focused on ways to integrate alternative drive systems into training with hands-on experience.
The Roadster incorporates stylistic elements from every era of Mercedes-Benz's history, such as the carbon-fiber bucket seats with hand-stitched leather covers and the distinctively styled fiberglass front section, based on the component from the Formula 1 racing bodies, according to the company.
(Source: Daimler)
Updated at 1:35 p.m. PT with corrected information on the supply arrangement and additional details.
Tesla Motors has signed a deal to supply power train components to Daimler for an electric version of the German auto giant's Smart mini-car, called the Electric Smart EV, which is expected to be available within two years.
Elon Musk, the CEO of Tesla, announced the deal at the North American International Auto Show in Detroit on Tuesday. On Sunday, Tesla unveiled a higher-end Sport version of its Tesla Roadster electric sports car.
Tesla will supply the battery pack and on-board charger for 1,000 Electric Smart EVs, a company representative said on Tuesday. Musk told told The Detroit Free Press that Tesla has been working on the deal for about a year and a half.
Tesla showed off the power train and battery pack of the Tesla Roadster at the North American International Auto Show this week.
(Credit: Sarah Tew/CNET Networks)"If the 1,000 vehicle fleet makes sense and the economics are compelling, that will expand to tens of thousands of vehicles per year," Musk was quoted saying. Daimler "sees the electric Smart as being a large percentage of EV (electric vehicle) sales."
Tesla is ramping up production of its first car, the Roadster, while looking to earn money through its power train business. Daimler is its first auto manufacturer customer.
A deal between Tesla and Daimler had been rumored for months.
In August, Financial Times Germany reported that the supply agreement was for electric Smart cars planned for a pilot to test lithium-ion battery Smart cars and a network of charging stations in Berlin, Germany.
Auto giant Daimler and German utility RWE will launch a network of 500 battery-charging stations next year, a trial meant to give electric car drivers the freedom to power up while on the go.
The project, called e-mobility Germany, will have Daimler and its Smart subsidiary supply 100 electric town cars. RWE will install and run the charging stations in Berlin, the companies announced last Friday.
A charging station and electric car, part of the "e-mobility Berlin" project to build a network of charging stations.
(Credit: Daimler)Charging stations are expected to be installed at people's homes as well as public spaces, such as offices, shopping centers, and parking lots.
The cars' lithium-ion batteries (from an undisclosed supplier) will be optimized for rapid charging and longer range. Those same batteries will be used in a Mercedes hybrid model as early as next year, the companies said.
The effort, modeled on a similar effort in London, is being financially supported by German government agencies as part of environmental policy.
"Our joint initiative is a good example of what can be achieved when policy makers, energy suppliers, and the automotive industry all work together toward the same goal," said Dieter Zetsche, chairman of the Board of Daimler, in a statement.
Project Better Place, founded by former SAP executive Shai Agassi, is taking a similar approach in an effort to make electric car ownership more attractive.
It has signed on the governments of Israel and Denmark to test a system where electric car drivers in a restricted driving area can replace batteries in a network of stations.
Utility RWE said it envisions that car batteries from the 100 electric cars in Berlin could feed electricity back into the grid to lessen the load during peak times.
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