First Drive Review
This May, the Mercedes-Benz B-class F-Cell will be the second fuel-cell-powered car to be delivered to consumers (Honda’s FCX Clarity being the first). What you might not know is that Mercedes-Benz was the first manufacturer to produce a fuel-call vehicle. Dubbed the NECAR5 (“new electric car”), it debuted in 1994 and was a single-seat van. Its fuel cell, battery pack, electric drive unit, and associated control devices took up all the interior space, making the van impractical for consumers, or just about anything other than research and marketing.
By 1999, Mercedes had shrunk the size of its system enough so that it could fit into the sandwich-floor architecture of the A-class. That version never made it to production, but in 2004, 10 Berlin residents were given fuel-cell-powered A-classes to drive. Those vehicles were precursors of the 2011 B-class featured here.
Did You Sleep Through Science Class?
The B-class is based on A-class architecture. The aforementioned sandwich design (a hollow void beneath the cabin floor that, among other things, funnels the engine below the passengers in a frontal collision) makes it an ideal candidate for alternative powertrains, as it provides a place to put some of the technology. This B-class actually has identical interior dimensions to its gas- and diesel-powered brethren. The only noticeable difference inside is the lack of a movable cargo shelf; the shelf is locked in the higher (normal to the untrained eye) position to make room for the battery pack.
What makes this B-class F-Cell a zero-emission car is its polymer electrolyte membrane fuel cell. Yes, it’s a mouthful. The simple explanation is that the fuel cell converts high-pressure hydrogen (H2) and oxygen (O2, gathered from the air) into electrical energy and water (H2O). It is some fancy chemistry, but it boils down to reverse electrolysis. If you recall junior-high science, when an electrical current is introduced to H20, the result is H2 and O2. For the fuel cell to produce energy and H2O, H2 is fed through a membrane that allows H2 protons, but not H2 electrons, to pass. Those protons join with the O2 on the far side of the membrane to complete H20, and the leftover H2 electrons (once the poles are aligned) generate an electrical current, thus powering the vehicle’s electric motor. Got that? If not, just remember it is reverse electrolysis, and you’ll survive a conversation with anyone holding a liberal-arts degree.
Actually moving the B-class F-Cell from point A to point B is a 134-hp electric motor coupled to a single-speed, direct-drive transmission. On startup, the motor gets the juice for movement from a 1.4-kWh lithium-ion battery array. The battery cells are the same as those used in Mercedes’ S400 hybrid, although there are many more of them here. The fuel cell kicks in at about 7 mph, delivering the needed wattage. The changeover is undetectable unless one is staring at the energy-flow display readout (similar to any hybrid’s display). The fuel cell and the battery will supply juice simultaneously, but only for brief moments, like when passing on the highway. It is similar to an overboost feature on a turbocharged engine. You can engage the battery boost by tripping the kickdown detent in the accelerator, and then the extra grunt can be felt.
Lease Now, Maybe Buy Later
California will get the majority of the 70-or-so F-Cell Bs slated for the U.S., with some ending up in Washington, D.C., too. The first cars will be on the road in May. Mercedes is following the Honda approach to fuel-cell ownership: You can’t own one, at least for now. All the F-Cells will be leased (all maintenance and nonaccident repairs included) for about the cost of a nicely optioned C-class. That translates to a monthly payment of about $800 to $1000, which is quite a bit more than the $600 per month commanded by the Clarity. Also, Mercedes is not sure how many individuals will be getting a B-class. The company wants to have as many people drive the cars as possible, and it hopes to have a majority of the U.S. allotment in fleets. So the LAX Hertz may get a couple to rent.
The hydrogen infrastructure is one of the biggest limiting factors to getting hydrogen-powered cars into the garages of the masses. This car’s three 10,153-psi carbon-fiber tanks (total capacity is 8.2 pounds) require H2 flow of about 11,600 psi to top off in about three minutes. By comparison, the FCX stores H2 at 5000 psi, a pressure at which more hydrogen stations can operate, meaning there are more available refueling locations. The Merc’s range is about 250 miles in combined driving situations, so owners won’t want to travel too far from a suitable filling station; 11 such stations are planned for the Los Angeles area by the end of 2010. Mercedes claims there will be 40 stations of this type by 2015. That’s good, because Mercedes also plans to sell—yes, sell, not just lease—fuel-cell vehicles in the U.S. by 2015. We’ll believe that when we see it.
Still a Real Car
The utility of the hatchback makes sense to us, but most of our fellow Americans wouldn’t be caught dead in one. Perhaps this B-class’s advanced tech could sway them. The high roofline allows for good front and rear headroom, and there is enough space in the back seat for two adults; three could squeeze in for a short trip. As stated before, cargo space is slightly limited when compared with that of a regular B-class, but there is plenty of room for a four-person weekend getaway.
Driving the F-Cell is relatively benign. There are no weird actuator sounds, no beeps. And there will be no gimmicky clean-energy slogans slathered across the doors, like those on our test car in Europe. The car weighs roughly 3750 pounds (about 550 more pounds than a standard internal-combustion B-class), and it accelerates like any small European compact—slowly, by U.S. standards. The power-to-weight ratio is slightly worse than the FCX’s, so 0-to-60-mph runs in the mid-nines are expected, as are quarter-mile runs in the high 17s. But the low-end torque (max torque is available at 0 rpm) makes it fell rather peppy. Fully electric steering comes without any real feel, but none was expected. The F-Cell uses regenerative braking, and this usually makes for a totally limp-feeling and nonlinear brake pedal. But brake feel, although light, is surprisingly smooth and linear, especially when we compare it to the pedal in the S400. Around town, the F-Cell is eerily silent, with just a little hum from the motor.
Abundant Energy
So where does hydrogen come from? Well, it’s the most abundant element in the universe. It’s in the air we breathe. A bunch of it burned up in the Hindenburg. And some of the H2 that Americans will be fueling their cars with will come from H2 farming locations. The cleanest of these use renewable energy, like wind, to power the collectors. Hydrogen is also a byproduct of some biomass manufacturing processes. There is enough produced to power about 750,000 cars a year, so Mercedes has a long way to go if it wants to use up all that byproduct H2. The first step is making the technology affordable, but if the inventor of the automobile ends up making production cars powered by fuel cells, then the technology is likely here to stay.
