A touch of green goes a long way

MANILA, Philippines - It was only a matter of time. With manufacturers like Ford, Honda, GM, and Toyota pumping out hybrid cars (most notably Toyota for making its Prius locally available), a luxury car maker like Mercedes-Benz had to get onto the eco-bandwagon. And as Donald Trump would say, “Think Big!”.

For its first venture into the technically complicated world of environmentally friendly cars, M-B decided to immediately set the bar with its flagship S Class. Realizing that an all-electric drivetrain was still years away from viability, M-B set about making the best possible hybrid drivetrain possible for the S Class, a system that would not only lessen its environmental impact but which would also improve on its performance.

To go about this, engineers came up with a lithium-ion battery, making the S 400 Hybrid the first production car in the world to have the type (other hybrids use Ni-Mh batteries). Just like with cellphone batteries, the li-ion type has several advantages over Ni-Mh. It has a higher energy density, better electrical efficiency, takes up less space, and weighs less compared to a Ni-Mh. The S 400 Hybrid’s battery merely takes up the same space in the engine compartment as a conventional starter battery. While the li-ion battery provides electrical power for the car’s various components such as the headlamps, ECU, and power assist, it’s also paired to an electric motor that acts as a starter and generator.

This 3-phase AC external rotor magneto motor develops peak output of 20 HP and a starting torque of up to 160 Nm with an operating voltage of 120 Volts. On the other hand, the conventional 3.5-liter V6 has also been engineered for optimal performance, using the Atkinson principle of a longer expansion phase than the compression phase for improved thermal efficiency and reduced fuel consumptions. A new cylinder head, different pistons and a modified camshaft with different camshaft control increase the output by 7HP to 279 HP. Finally, the 7G-Tronic 7-speed automatic transmission has also been specially configured for the hybrid drivetrain, featuring specific software programming and an auxiliary oil pump.

So how does the hybrid system work? An ECO start/stop function detects when you’re coming to a stop at less than 15kph, switching off the V6 and shutting down fuel consumption. When it’s time to move, the electric motor restarts the main engine quickly and imperceptibly, as well as providing a little extra boost to get up to speed. At cruising speed, the engine management system automatically moves the load point of the V6 over to lower fuel consumption. Rolling to a stop, the system has a “recuperative function”. The electric motor acts as a generator and converts the rolling kinetic energy into electrical energy, storing this into the li-ion battery. The system also features “regenerative braking”, which increases generator output when the driver steps on the brake pedal, creating more electrical energy while also increasing the braking effect. On highways, the hybrid system is not as important as the heavy S 400 body needs every horse that the conventional V6 can provide. In this case, the specific modifications to that engine and the 7G-TRONIC automatic transmission come into play, reducing fuel consumption and lowering fuel consumption without sacrificing performance.

Combined with other energy saving features such as a reduced belt drive, electric power steering and A/C compressor, Atkinson combustion process, and new camshaft load points, the S 400 Hybrid system saves up to a claimed 0.9 liters of fuel per 100 kilometers on the highway. In the New European Driving Cycle, the combined city/highway fuel consumption is only 7.9 liters per 100 kilometers (12.66kpl). At 186 grams per kilometer, it also has the lowest C0₂ emissions for its vehicle and performance class, and even improves on the conventional S 350’s fuel consumption by up to 2.2 liters per 100 kilometers, and C0₂ emissions by nearly 21 percent.

Price? A mere P10,200,000, which begs the question “Why would the multi-millionaire who can afford this car care about such a trivial thing as fuel consumption?”. Ah, but you see, even tycoons like to do their bit for Mother Earth. Just because they can afford a car that costs as much as a nice house and which comes with all the trimmings like premium leather, concert-quality audio, and electronics derived from the Space Shuttle doesn’t mean they’re carefree enviro-slobs.

With reduced fuel consumption comes reduced emissions. And reduced emissions means a smaller carbon footprint. Which means an S 400 Hybrid owner theoretically has a smaller role in global warming.

What’s more, the car is heavily into the “Recycle” mantra. The li-ion battery is rated up to 300,000 kilometers, and its recycling/disposal process produces 18% lower C0₂ emissions than a comparative model. A total of 45 S-Class components such as wiring ducts and underbody panels are made from recycled, high-quality plastics. 27 components are also produced from natural materials, such as the wool seat upholstery and the coconut fiber-and-natural-latex driver’s backrest.

Just to maximize its material consumption, the backrest cladding uses wood-fiber, and the attached retention points are made directly from the waste materials during the production of the cladding, allowing a closed materials loop.

Fuel-saving drivetrain, recyclable materials, lower emissions... even for those who turn everything they touch into gold, a little bit of green in the S 400 Hybrid can surely go a long way.