Here is a somewhat lengthy article you may find interesting .
Harvey
Daimler-Benz Unveils PEM Bus Demonstrator, PEM Subcompact to Follow This Fall
STUTTGART, GERMANY - Almost exactly a year after unveiling its milestone consumer-friendly PEM fuel cell NECAR II minivan (H&FCL June 96), German car-maker Daimler-Benz followed up by introducing its first hydrogen-fueled PEM city bus NEBUS (new electric bus) demonstrator at a standing room-only press conference here last month.
And some time this fall - possibly at the Frankfurt Auto Show - the German carmaker plans to complete its hydrogenous hat trick by presenting the third ace up its sleeve - the reformed-methanol PEM fuel cell version of its new subcompact, the so-called A-Class model, according to a company executive.
NEBUS is the fuel cell version of Daimler-Benz's O 405 N model, a 12-meter, low-floor city bus with 34 seats plus standing room for 24 straphangers. The Ballard-designed fuel cell consists of ten 25 kW stacks of 150 individual cells each, providing a total output of about 250 kW (about 340 metric HP). Of that total, 190 kW (260 HP) are available for traction, electrical systems and air condition- ing.
Compressed hydrogen is carried in seven 150-liter, 300 bar roof- mounted gas bottles that hold about 45,000 liters of compressed gaseous hydrogen. Depending on the daily drive cycle pattern, this is sufficient for up to 250 km (156 miles), "more than enough for the average daily requirements of 140 to 170 km (88-106 miles)," said Dr. Kurt Lauk, Daimler's management board member responsible for utility vehicles.
Electric Hub Motors
A major innovation is the use of infinitely variable 75 kW (about 100 HP) max. asynchronous electric hub motors in lieu of a conventional electric motor driving the rear wheels. The drivetrain was designed and built by German transmission maker ZF. Daimler- Benz says this is comparable to the output of conventional diesel engines in current European transit busses.
Another innovation is the use of solar cells integrated into roof vents that can be opened in hot weather. The current they produce is used to operate ventilation and air conditioning ducts.
Added Lauk, "The launch of the fuel cell bus is a vivid example of how the corporation, as part of its innovation management, exchanges technology know-how between the central research and the utility and passenger vehicles areas, benefitting future prod- ucts."
Lauk said the impending availability of zero- or near-zero emission busses should call for a reevaluation of German subsidy p- olicies which are partially based on the assumption that rail transit such as subways and commuter trains is especially benefi- cial for the environment. Noted Lauk, "If these subsidies were to be continued and prorated according to number of passengers served, then busses should have received an additional DM 9 billion ($5.3 billion). That would have been enough to buy a fleet of 1,800 fuel cell busses at prototype prices - enough to allow the cities of Hamburg, Duesseldorf and Munich to completely exchange their existing bus fleets for fuel cell fleets."
This first prototype was scheduled to get its initial interna- tional airing at the World Public Transport Congress, held here in Stuttgart, in the first week of June.
Klaus-Dieter Voehringer, member of the management board for research and technology, cautioned the fuel cell bus is still a pilot project. "We will make the basic decision whether we will start the fuel cell's series development before the year 2000," he said. Still, given the rapidity of introduction of various fuel cell vehicle prototypes in quick succession, outlays in the hun- dreds of millions, the intertwining of Daimler-Benz with Ballard and other signs make it seem that in their heart of hearts, Daimler-Benz top management has pretty much committed itself to the plunge.
20 Fuel Cell Busses By 2000
Dr. Ferdinand Panik, Daimler-Benz Senior Vice President and head of fuel cell activities, told H&FCL in a transatlantic phone interview that the bus would first be tested in house for roughly the next six months by the company. "After that, in 1998, I'd like to have it run somewhere as a demonstrator. Beginning in 1999 or 2,000, we want to build and deploy about 20 busses worldwide to get feedback and launch initial marketing," he said. He counts the six Ballard fuel cell busses now under construction for Chicago and Vancouver (H&FCL, Apr. 96, Oct. 95), as part of that total, he said, "But, we've probably progressed another step in terms of fuel cell technology" beyond those six, he added.
"The point is not to push out one bus after another cookie-cutter fashion just to show them off," Panik said. "We now really want to approach customers. For that we need a phase of solid development, and that's what I intend to do to achieve solid technology."
Also, costs need to be reduced a great deal, Panik added. He estimated the cost of the first prototype bus at about DM 2 million ($1.2 million), "but in two years, I'd say about DM 800,000 ($470,000)."
Panik acknowledged that while the wheel hub motor concept is more energy-efficient, it has the disadvantage of increasing "unsprung weight," - the mass of material that bounces up and down on the road without benefit of damping by the suspension, reducing comfort and handling ease. However, NEBUS also incorporates an active electronically controlled suspension system, that keeps the bus level even in curves, smoothes bumps and affords better driver control. In fact, it can be tuned to induce the bus to lean into a turn, like a motorcycle rider.
So far hub motors are envisioned only for busses, Panik said. Passenger cars, with their much higher comfort requirements, are unlikely to be equipped with the system.
Voehringer told the roughly 240 reporters that Daimler-Benz is looking at fuel cell applications for other transportation systems as well as stationary use. Without providing details, he said the company expects to introduce a decentralized stationary fuel cell system ready for deployment within the next twelve months. Panik amplified by saying this referred to both Ballard PEM systems as well as molten carbonate fuel cells under development at Daimler's MTU subsidiary.
Also well under way is development of an on-board methanol reformer system which Voehringer said the company expects to unveil reasonably soon. "For the future we're betting on methanol," he added, "a liquid and chemical raw material that is available in large quantities, that can be produced from biomass, and refueling can be done just like gasoline today."
PEM A-Class Subcompact Before End of Year
In the interview, Panik said also that the PEM fuel cell prototype version of the new A-Class subcompact operating on reformed methanol would be shown publicly before the end of the year. While it's not certain, it's reasonable to assume this prototype may debut at this September's Frankfurt Auto Show, traditional venue for German carmakers to show off their latest and sexiest.
He confirmed the methanol reformer is a variant of steam-reform- ing, developed in-house by Daimler-Benz, that it would be small enough to fit into the A-Class envelope, and that there would be no larger intermediate version - a methanol PEM package installed in a larger, less constrained standard station wagon or sedan - first.
Panik said so far there are no technical papers on the system, "but we'll have them as soon as we launch, and that's going to be soon."
Despite its emphasis on methanol as a consumer-friendly fuel, it was clear, however, that Daimler-Benz has not written off hydrogen at all. Board member Lauk said, for instance, there is no need wait for methanol advances: "A fuel cell bus powered by hydrogen has a range of 250 km (156 miles), which is absolutely sufficient," especially in view of tankage technology which has made significant advances, he noted.
Interest in "Carbon Whiskers"
Panik added the company is working "closely" with Drs. Terry Baker and Nelly Rodriguez, chemists at Northeastern University, Boston, MA who have developed a "carbon whiskers" hydrogen storage concept that they say stores an incredible 75% hydrogen by weight and that conceptually would permit design of a 5,000 mile range refueling system (H&FCL, Feb. 97).
Panik said so far Daimler-Benz has not conducted independent tests of its own of the Rodriguez-Baker technology, mainly because the sample size has been too small. "That's something that's still ahead," he said. But, he added, "what we have seen so far has actually been quite convincing.
"Even if we don't achieve 100% of our dreams - even 50% would be pretty good," he said.
Small, Quick-Response Fuel Cell Team
A main reason for the rapid progress of the Daimler-Benz-Ballard fuel cell program seems to have been the creation of a small quasi- independent corporate entity about a year ago dubbed "Projekthaus Brennstoffzelle," which translates roughly into "Fuel Cell Project Center." Panik, who heads the center, explains that it combines under one management roof all relevant departments: production, purchasing, sales, public relations, finance and development. Total staff is about 150. The center is housed so far in offices in Esslingen, a suburb of Stuttgart, but it will move shortly to a brand-new building somewhere in the vicinity - Panik won't reveal the location "because we're still deciding between locations, and I don't want to tip our hand" - which it will share with Ballard's staff in Germany.
Creation of the center was the idea of Daimler-Benz top manage- ment, says Panik: "Because this subject is so strategically impor- tant, and because we wanted to do this quickly (it was decided) not to make it part of the Daimler-Benz organization but to operate like a small company that drives everything," said Panik. |
