Compared to the violent little explosions of air and fuel that take place within the cylinders of an internal combustion engine, the rotation of magnets within an electric motor is a quiet and elegant way of creating power for motive force.
However, in being devoid of aural stimulation this near silent mode of propulsion lacks half the ingredients that normally stir the emotions of enthusiasts. An impressive rush of torque apart an electric motor simply lacks the visceral accompanying sounds that we associate with speed.
Yet if you use an electric car for commuting with zero emissions and background silence as a calming influence, leaving a piston engined car as a source of stimulation for the weekend, then it suddenly all makes sense.
Today we are riding shotgun in the GLC F-Cell, a car that you will be able to buy from your local Mercedes dealer before the year is out. The fruit of Mercedes’ research into using hydrogen fuel cells to produce the power for an electric motor, the F-Cell (Fuel Cell) is a more versatile alternative to the pure electric car, which remains a non-starter where range and refuelling speed remain significant stumbling blocks compared to conventional cars.
Bereft of the sound of an internal combustion engine the cabin of the GLC F-Cell is as quiet as any electric car. This means that as you go down the road the relative silence draws attention to sounds normally masked by engine noise. Thus the relatively low rolling noise made by the tyres of the standard GLC suddenly leap into prominence.
Tyres have become much quieter in recent years, encouraged by EU and Swiss legislation aimed at the reduction of vehicle drive-by noise. The only way to reduce the tyre noise heard in the F-Cell’s cabin would be to adopt the tyre technology used to further improve acoustic refinement in the Mercedes-Maybach. This features a band of special acoustic foam bonded to the inside of the tyre aimed at reducing rotational noise by at least 6.0 dB.
The GLC is the only car in its class to offer air suspension as an option. Our F-Cell was so equipped, and so managed to deliver a cosseting ride despite the 20-inch diameter wheels shod with 255/45R20-inch tyres that give it its purposeful stance.
Because an electric motor delivers peak torque just above zero revs, electric cars are noted for their strong acceleration, and even from the passenger seat I could feel the instant and relentless surge each time my test engineer driver depressed the drive-by-wire throttle on a clear stretch of road.
If you are a torque junkie, the thrust will be addictive, and the knowledge that you are having fun while emitting only oxygen and water into the atmosphere is a bonus.
The F-Cell is significant for several reasons, not least because Mercedes and Toyota have both thrown their not inconsiderable weight behind the technology, whilst continuing to develop pure electric vehicles in parallel. When you consider that Toyota, currently the second largest car manufacturer in the world, was the industry pioneer of hybrid cars for the masses, for them to now back the Fuel Cell horse is not something to be taken lightly.
Hydrogen as an automotive power source has been on the cards for many years, but not originally in Fuel Cell form. BMW and others experimented with it as far back as the 1990s using it as an alternative fuel for existing internal combustion engines, with water and oxygen being the tailpipe emissions.
Fuel Cell technology comes at the problem from another way by using hydrogen in a chemical reaction to generate the electricity that powers the electric motor and charges the battery.
As the size and weight of the hydrogen motor is close to that of a petrol or diesel engine, the frontal crash performance is unchanged. The battery pack at the rear is identical to the GLC Hybrid, so no change in mass distribution there either. With a kerb weight close to that of the Hybrid version the GLC retains similar chassis dynamics.
That however, is where similarities to the petrol or diesel GLC end. Hydrogen is very light and the difference in weight between full and empty tanks is about 2.0kg. Compare that to the significant 30kg weight difference between a full and empty petrol tank and it is clear that the F-Cell has a more consistent mass distribution, so its handling will be totally consistent no matter what the state of its hydrogen supply.