The first Mercedes-Benz fuel cell car was a wagon that had to drag around over 1500 pounds of fuel cell paraphernalia, compromising performance (56 mph top speed) and range (limited to 80 miles). As is the way with technology, things have become smaller and better. Currently, M-B has 100 fuel cell vehicles being tested around the world, from which a team of 150 scientists and engineers extract valuable information to prepare a true car of the future.
Being 40 percent smaller, the fuel cell stack in the F600 Hygenius fits under the cabin. It can start in cold temperatures (down to minus 77 degrees F), courtesy of the new gas-to-gas humidifier and plastic film which expels water left in the stack when the driver powers down at the end of a drive (so no risk of the system freezing). Maximum output is 115 hp and top speed moves up to 106 mph, with an equivalent consumption of 81 mpg and a 248-mile range. Newly developed tanks can hold the eight pounds of hydrogen at a 700-bar pressure, twice as much as before.
During normal acceleration, the electric motor is fed energy from the fuel cell (up to 90 hp). An electric turbocharger forces air into the fuel cell. Any extraneous energy goes to recharge the high-voltage battery. When starting and overtaking (a sudden need for more power), the battery comes into play and helps raise output to its maximum. On low-speed maneuvers, the battery is the sole energy provider, generating up to 75 hp (the new lithium-ion device doubles the former nickel metal-hydride output). If braking, the motor changes functions automatically and acts as a battery charger. The prompt response and silent operation of this fuel cell system makes the F600 pleasant to drive, especially in urban areas.
The under-the-vehicle positioning of the tank, motor and battery make it possible for a compact car (171 inches) to offer generous interior space (37 inches between the driver's and the rear passenger's seat, roughly the roominess of an E-Class). And the rear seats can slide back 16 inches to create 53 inches of legroom.
Interior flexibility is highlighted by backrests that swing forward and support a rearward-facing occupant, presenting new possibilities for child safety and simplifying the task of attending to children when traveling. The driver also benefits from a two-piece backrest that relieves strain on the spine and features cushions with electric motors that enable precise adjustment to the contours of the driver's back. Once molded to the body, the backrest follows any movement.
The dashboard concept (a creation of the Como Italy design studio-the exterior was styled in Japan) abandons convention with a top section that appears to be suspended. Between the front seats is a sophisticated command controller that can differentiate between the two front occupants: recognition is based on electrical signals transmitted from the skin, after which, pre-set preferences can be applied (temperature, seat adjustment, etc.). The command screen can also be swiveled to give the front passenger a better view and prevent the driver from being distracted. Virtual displays divert and enlarge images projected to a point 55 inches ahead of the driver (no need to refocus from distance viewing to close-up).
The fact that Toyota announced that its future hybrids and fuel cells will not feature lithium-ion batteries has raised eyebrows. Rosario Berretta, manager of M-B's fuel cell fleet, explains: "We conducted all the necessary safety tests and there is no reason to postpone the use of lithium-ion batteries. We would not introduce them had we any kind of question."
Pricing is still unknown, but engineers and marketers are aware that it will most likely flop if it costs more than 20 percent over the retail price of an identical car with an internal combustion engine. Aside from the infrastructure and hydrogen supply issues, the vehicle still faces a major technical challenge: system durability is currently at 2,000 hours/62,000 miles (peaking at 3,000 hours/93,000 miles under controlled conditions). But Mercedes knows that, in order to match a standard vehicle's longevity, it will need to reach around 4,000 hours/124,000 miles.