Earlier this year, the first-ever manned flight of a fuel cell-powered light aircraft completed testing in Spain. It was modified by Boeing Research & Technology Europe to incorporate a hybrid low-emission engine, containing a proton exchange membrane (PEM) fuel cell power system and lithium-ion batteries to power an electric motor coupled to a conventional propeller. Another recent fuel cell first was the Suzuki Crosscage, a hydrogen-fuelled concept motorcycle unveiled at the 2007 Tokyo Motor Show. What is common to both is Intelligent Energy, a specialist company that provided the fuel cell power systems and which has just unveiled its latest project in the automotive sector.
This is a relatively new company that came into being just seven years ago. However, almost at once it acquired Advanced Power Sources, a UK research and development company based at Loughborough University that had been working on the early prototyping of fuel cell products and pre-commercial development of its proprietary fuel cell technology since 1995. It then acquired U.S.-based Element One Enterprises in May 2003 that specialized in fuel processing, hydrogen generation and hydrogen refueling technology. This was followed 11 months later by the purchase of Meso Fuel Inc., a New Mexico company with strong links with the U.S. defense community, developing micro-devices for the conversion of liquid and gaseous hydrocarbons into pure hydrogen for storage and use in PEM and other fuel cells. It is therefore a bit of a powerhouse of a company.
Its latest venture is a collaborative research project with the PSA Peugeot Citroèn Group, Bosch and Prodrive which has resulted in the development of a concept fuel cell vehicle. What makes this program stand out, though, are the claimed technical advances plus the relatively low cost of the program. While the French automaker and Bosch have not revealed the amount of funding they have put into the three-year project, Intelligent Energy and its UK partners including Prodrive received $7.75-million from the UK government, $3.4-million of which was targeted at partially financing the design of the fuel cell system. The end result of this program that commenced in early 2005 is the "H2Origin," a conventional electric vehicle with integrated fuel cell technology but with a 300-km (186-mile) range and the ability to operate at temperatures as low as -20°C. This was to meet PSA Peugeot Citroen's specific goal of being applicable for a future-generation delivery vehicle which requires frequent stop-and-go driving, in urban and suburban environments.
The all-metal 10-kW PEM fuel cell power system for this new project relies on Intelligent Energy's Series 7 design that features power densities that are in excess of 2.5 kW per liter, which it claims are class leading, and reduced component count. This ensures that they are more compact and far simpler than conventional fuel cell systems and are easily integrated within a diverse range of applications. They have a lifetime of 5,000 hours, or about five years, assuming an average use of three hours per day. Integrated humidification and innovative cooling, which operates without the need for secondary coolant circuits, eliminate much of the conventional system component count, resulting in fuel cell power generation systems that are compact, high performing, reliable and less costly to manufacture.
Intelligent Energy also claims that its fuel cell stacks and systems are set apart from conventional systems by the fact that they are designed from first principles, combining novel fluid and thermal management techniques with metal plate architecture. The cell packing density can be twice as high as in conventional designs, maximizing volumetric power density. This meant that when it came to vehicle packaging, the fuel cell could be fitted more easily under the hood, therefore retaining payload volume similar to that of a production vehicle. A side benefit of this is that it would keep R&D and tooling costs under control in adapting the vehicle to fuel cell operation—a considerable advantage if this technology is to be incorporated into future production vehicles, maintain the developers.
One of the weaknesses of fuel cells is their sensitivity to temperature due to the generation of water in the electrochemical cycle characteristic of fuel cells. However, Intelligent Energy claims to have overcome this with the project objectives at the outset calling for the achievement of full power inside two minutes at temperatures down to -20°C. This is due to the addition of heating systems, together with the incorporation of "start and stop" engine control strategies. Furthermore, the system includes a fuel cell cooling module for optimal operation at temperatures up to 37°C. This temperature range therefore allows vehicles to be operated in a wide variety of climates, excluding only certain exceptionally hot or cold areas of the world. However, this does not preclude the maximal operation of this system in temperatures outside this range in the future.
"Our fuel cell expertise and systems integration capabilities have been proven yet again in developing the power system and incorporating it into this vehicle," says Henri Winand, CEO of Intelligent Energy. "We have made the fuel cell system robust and compact enough for real-world clean motoring applications and have gained invaluable experience through the collaboration with PSA Peugeot Citroèn."
Another problem area that the program has addressed is that of hydrogen storage. PSA Peugeot Citroèn is participating in a joint European program (StorHy-Storage of Hydrogen for Automotive Applications) between vehicle manufacturers and technology partners centered on the storage of hydrogen at a pressure of 70 MPa. This is important because storing hydrogen under this sort of pressure improves the range of electric vehicles as it increases the amount of hydrogen that can be kept in a given volume by nearly 70%. With the H2Origin project, it claims that it has developed a novel hydrogen storage system in which the carbon fiber and resin hydrogen tanks are similar to those used by scuba divers. They have been put through extremely rigorous tests to ensure their resistance to fire, shock and pressure. They have been located on a sliding platform on the H2Origin concept car and housed in the rear cargo area of the vehicle, a design already used on other technology demonstrators, including the Taxi PAC. The advantage of this is that it keeps most of the standard payload area available for cargo.
While the H2Origin represents a considerable advance in many areas, the project partners still acknowledge that there is still some way to go before such a vehicle becomes a commercial reality. They point to cost, weight, durability and reliability issues that all need to be addressed before such a technology can become a viable alternative to the internal combustion engine. Which is where another concept car, also partially funded by the UK government, makes an appearance. With backing from Energy Saving Trust's Low Carbon R&D program, funded by the UK Department for Transport, MIRA has unveiled a retro-fit hybrid conversion that it claims unlocks the potential to save 61% on fuel costs and lower tailpipe emissions by 39% without designing a new car. As a "plug-in hybrid" the vehicle can charge its batteries by running its engine or by plugging into the mains. Plug-in hybrids are at the vanguard of new vehicle design yet MIRA claims it has taken the idea one step further to make the concept far more practical and useful for motorists.
"Despite advances in powertrain technology you can still obtain electricity from your domestic provider far cheaper and greener than you can produce it via an automotive combustion engine, so 'plug-in' hybrids make sense," says Derek Charters, MIRA's Advanced Powertrain Manager. "With this project, we've removed the primary limitation of the 'plug-in' hybrid concept by allowing the battery pack to come to the mains, rather than having to park right next to a socket which is more than a little difficult if you live in an apartment." Known as the Hybrid 4 wheel drive Vehicle (H4V), it is based on the small Skoda Fabia. The 50/50 hybrid derives power jointly from a 60-kW gasoline engine at the front and two 35-kW inboard motors powering the rear wheels through MIRA's clever e-differential. Overall, the H4V differentiates itself from the standard model by returning 53 mpg (U.S.), as measured on the EU drive cycle whilst general levels of performance, such as top speed and acceleration, are similar to that of the standard car.
The battery pack is arranged into three portable cassettes each capable of storing 30 kW that can also power external devices, including a range of lifestyle accessory items. The very latest nano-particle technology has been applied to increase the energy density of the lithium-ion phosphate batteries which ensures the energy pack is as lightweight and compact as possible while delivering superior voltage stability over the charge range. The same battery technology is evident in the separate low voltage circuit used to start the engine, insuring the car's impeccable "lead free" green credentials.
"MIRA's hybrid vision is to lower tailpipe emissions and deliver better fuel efficiency than an equivalent diesel, at a diesel level 'on-cost' whilst delivering driver delight features such as an EV mode and 'two-pedal' town driving," says Charters. However, MIRA claims that out-and-out super-frugal figures were never part of its aim-if it was, it would not have chosen the Fabia-as it wanted to prove the point that the base car was largely unimportant. What is important, though, is that the donor vehicle's specification includes modern features such as a throttle-by-wire system and some other basics to avoid duplicating unnecessary workload.
"This project has designed a new system allowing hybrids to be more flexible and practical for every day use," says Philip Sellwood, Chief Executive of the Energy Saving Trust. "With over 20% of the UK's total carbon emission produced by road transport every year, these advances in technology are vital. Over 80% of people believe that climate change is having an impact on the UK right now, so it is important to bring more technology like these to the market place."