BMW's Vision EfficientDynamics concept uses a gas engine and three electric motors.
(Credit: CNET)
Japanese automakers pioneered hybrid cars, but German companies have been slow to join in. At the Frankfurt auto show, BMW, Mercedes-Benz, and Porsche showed off their latest efforts, a mix of research and production vehicles. Most of these cars don't stint on the power, merely using hybrid systems to boost efficiency without shooting for stellar fuel economy.
Volkswagen also comes in with a hybrid concept in its quest to build a car that will only burn one liter of fuel over 100 kilometers. And Lexus shows off a luxury compact concept with a full hybrid power train as a way of testing the waters in the European market.
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.
Young oil palms waiting to be planted.
(Credit: Neste/Ismo Henttonen)In Berlin on Tuesday, Daimler and Finnish oil company Neste Oil announced the results of a year-long pilot project in which 14 Mercedes trucks and buses ran on nothing but sustainable biodiesel for one year.
Specifically, five medium-duty Mercedes-Benz Atego trucks, five heavy-duty Mercedes-Benz Actros vehicles, and four Mercedes-Benz Citaro city buses were run exclusively on Neste's sustainably produced NExBTL renewable diesel fuel.
The biofuel, which includes hydrotreated vegetable oil (HVO) made from palm oil, is something Neste has been known to be working on in order to meet its goal of "100 percent sustainably produced" oil by 2015.
The result after one year was a 15 percent decrease in nitrogen oxides, and, when taking into account the entire food chain from plant cultivation to car engine use, the CO2 emissions caused by the vehicles were reduced by over 60 percent, according to project statistics provide by Neste.
The project has now been extended to three years with more results to be reported in 2011.
The Chevrolet Equinox Fuel Cell takes part in the Hydrogen Road Tour.
(Credit: GM)Electric cars have been getting plenty of buzz lately, but the development of hydrogen fuel cell vehicles is still going strong. The California Fuel Cell Partnership, along with Powertech Labs, National Hydrogen Association, and U.S. Fuel Cell Council, will seek to regain the spotlight with a road trip to demonstrate the practicality of these vehicles.
The road tour route runs up the West Coast, from Chula Vista to Vancouver.
(Credit: California Fuel Cell Partnership)Twelve fuel cell cars from seven automakers will drive from Chula Vista, in Southern California, up to Vancouver, Canada, a trip of 1,700 miles. Vancouver was chosen for the destination because it will play host to the 2010 Winter Olympic Games, where a fleet of fuel cell buses will provide transportation.
Fuel cell cars that will be making the trip include the Chevy Equinox Fuel Cell, Mercedes F-Cell, Honda FCX Clarity, Hyundai Tucson FCEV, Kia Borrego FCEV, Nissan X-Trail, Toyota FCHV-adv Highlander, and Volkswagen HyMotion. The cars, which have ranges of 200 to over 500 miles, will be relying on a mobile refueling station for their hydrogen needs.
The tour starts on May 26 in Chula Vista, and ends on June 3 in Vancouver. Stops have been scheduled along the route so the public can get a chance to see these cars. Check the Hydrogen Road Tour '09 Web site to see if there's an event near you.
We had a random encounter with this hydrogen-powered F-Cell vehicle.
(Credit: CNET)While out testing the very stylish Aston Martin DB9 Volante in the Santa Cruz Mountains recently, we ran across the car's opposite, a Mercedes-Benz F-Cell research car. We caught up with the F-Cell (easily) and followed it to a vista point, where we cornered its driver and started grilling him about the car. It's not often you see the future of the automobile out in the wild like this.
This F-Cell was from the first generation, built into Mercedes-Benz's A-class platform, a small vehicle that's not sold in the U.S. Its 5,000-psi hydrogen tank feeds a fuel cell that produces electricity, in turn powering an 87-horsepower electric motor.
The driver of the car was a Mercedes-Benz engineer stationed with the car in Palo Alto, California. The company maintains many test fleets. He had pulled into the parking lot not because he thought James Bond was on his tail, but to plug his laptop into the F-Cell and download diagnostic data. Mercedes-Benz has logged well over a million miles with these F-Cell cars, and every mile yields useful data about performance in the real world.
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(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)
The Mercedes-Benz ML320 BlueTEC was unveiled at the New York auto show.
(Credit: CNET Networks/Sarah Tew)Mercedes-Benz showed off the BlueTEC ML320 SUV at the 2008 New York auto show. According to Mercedes-Benz, its AddBlue technology makes the ML320 the world's cleanest diesel. The ML320 BlueTEC uses a turbocharged diesel 3.2-liter V-6 engine, producing 210 horsepower and 398 foot-pounds of torque. That engine is mated to a seven speed automatic transmission, giving it wide range of gear ratios appropriate for city and freeway driving. The ML320 BlueTEC represents the first use of AddBlue technology in the U.S. AddBlue is a urea-based liquid that, when injected into the exhaust stream, converts 80 percent of the nitrogen oxide into ammonia. The ML320 has a 7 gallon tank for AddBlue that needs refilling every 10,000 miles. With AddBlue, the ML320 meets the emissions requirements of all 50 states. Mercedes-Benz will follow the ML320 BlueTEC with R-Class and GL-class BlueTEC models.
The Mercedes-Benz S400 BlueHybrid will use lithium ion battery technology.
(Credit: CNET Networks)Current mass-produced hybrid cars use nickel-metal hydride batteries, but Mercedes-Benz says it will launch the first hybrid with lithium ion batteries. Lithium ion batteries are more efficient than nickel-metal hydride batteries and have a better weight-to-power ratio, and are used in the all-electric Tesla roadster as well as in many plug-in hybrid conversions. But large stacks of lithium ion batteries can overheat, a serious problem in an automotive application. Mercedes-Benz announced it has 25 patents around making lithium ion suitable for cars, detailing a key breakthrough of integrating the battery with a car's climate control system, which maintains the battery temperature at between 60 degrees and 95 degrees Fahrenheit. In this temperature range, lithium ion batteries offer optimal performance and long life.
Mercedes-Benz will first use lithium ion batteries in its S400 BlueHybrid, launching in 2009. The S400, unveiled at the 2007 Frankfurt auto show, will use a 3.5-liter V-6 engine complemented by the hybrid system. Mercedes-Benz claims 30 mpg for the S400 and a 0 to 62 mph time of 7.3 seconds with its 300 horsepower.
The new face of Mercedes-Benz
(Credit: CNET Networks)Mercedes-Benz is apparently planning to use next week's Geneva auto show to unveil two new fuel-efficient versions of the C-Class sedan in the first example of a new line of "eco variants" of its main model lineup. According to Just Auto, Mercedes is planning to roll the strategy out to 20 other models over the course of the next year. BMW is also expected to launch a green concept car at the Geneva show. Both luxury German automakers are likely to be among the hardest hit by new European Commission legislation for stricter emissions and fuel efficiency standards, and consequently have been making efforts to find more efficient versions of their performance-focused lineups. At last year's Frankfurt auto show, Mercedes showed off a number of diesel-electric hybrid concept cars that are scheduled for production in 2010 as well as its Diesotto engine, which uses turbo charging, direct injection, and diesel-like compression to maximize power and fuel economy.
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