For those who have followed the vicissitudes of Mercedes-Benz’s fuel-cell development, the arrival of the prototype F-cell B-class in Britain is a tribute to the dogged determination of a generation of engineers.
This goes right back to the first Necar 1, a van filled to the gunwales with fuel-cells, wires and tanks that I saw staggering around a car park at Ulm University in 1994.
In 1999, the proselytising of Dr Ferdinand Panik over Necar 4, the first drivable fuel-cell car, was much criticised, but at least it pushed the technology in front of the press, public and politicians.
Through subsequent Necar models and the dark days of the merger with Chrysler, Mercedes engineers have gnawed away at the problems, and in November it brought two F-cell B-class models to participate in the Brighton-to-London low-carbon car run.
Two? That’s because in Britain there’s nowhere to fill up with hydrogen fuel. So while total tank capacity of 3.8kg of gaseous hydrogen fuel in three 10,000 psi spun-carbon tanks will take each car about 240 miles, Mercedes engineers didn’t want to risk an embarrassing failure.
Not that there was much chance of that, as the B-class is an extraordinarily complete vehicle, even down to the special instrumentation that indicates the recharging capacity in the 1.4kWh lithium-ion battery.
While the Honda FCX Clarity has received the plaudits as the world’s most advanced fuel-cell car, Mercedes has taken a different route to achieve similar ends.
The sandwich-floor construction of the B‑class was originally designed for the A-class as a means of packing the driveline under the floor to maximise passenger space.
It had its problems, not the least of which was a failure to pass the fiendish elk swerve test in 1997, but it is nevertheless very clever and has come into its own with the different packaging requirements of fuel-cell and battery electric cars.
The Mercedes fuel cell was born out of the company’s co-operation with Canadian specialist Ballard, but this unit is a radical departure. It still uses bulky carbon separators between the cells, but instead of a power-sapping and potentially noisy mechanical compressor pushing air into the cell it uses an electric fan, which draws less current, is quieter and also allows the cell to be easily purged of water when the motor is stopped, to prevent low temperatures from causing damage. To this end, they are surrounded by a sort of hi-tech pan scourer that allows fast draining of the 107bhp (80kW) units.
Mercedes claims the new cell system has been optimised for the B-class and is about 40 per cent smaller and 30 per cent more powerful than the A-class system it replaces. The fuel-cell has been restart-tested down to -13F (-25C).
Performance is quoted at 0-60mph in 11.4 seconds with a top speed of 106mph. Starting is a matter of turning a key and waiting a couple of seconds for the systems to check the integrity of the fuel cell and hydrogen lines.
Then you’re off. Lots of torque at low speed, pleasingly silent operation and swift mid-range acceleration are the most noticeable points. We drove around Surrey and onto the M25, where the B-class mixed with fast-moving traffic with no problems.
Lifting the throttle results in instant deceleration, which feels a little weird, and we’d prefer the option of coasting until you brake, but that’s a minor criticism.
Other than that it’s a credit to maturing fuel-cell technology and the engineers. It is as quiet as a kettle and produces no more emissions, but questions remain over the hydrogen infrastructure and particularly the high cost of on-board storage.
Mercedes will have 200 on test in America and Europe. It would be nice to think they’d be tested in Britain as well, but we can’t fill them up. Is anyone out there listening?
