The S-Class is a flagship sedan manufactured by the German automotive giant. It first came in 1972 and soon became a world-famous luxury sedan. Everything in this opulent car is a marvel of engineering including its engines and transmissions. Let us have a look at the powertrain of the S-Class.

Engines

Mercedes-Benz paid tribute to the almighty V12 by introducing an AMG S65 Final Edition; only 130 examples were developed worldwide. It was aimed at collectors of prodigious twelve-cylinder automobiles. Presently, this über-luxurious sedan only comes with V6 and V8 engines. However, Mercedes-Benz has brought only the six-cylinder motors to India.

OM 656 - Diesel

Firstly, there is an inline-six diesel engine which is the most powerful diesel fitted to a Mercedes-Benz vehicle ever. This is an advanced diesel engine created to deliver more power while consuming less fuel and emitting lower emissions. To achieve that, Mercedes-Benz has utilised stepped-lip bowl piston geometry, two-stage turbocharger and camtronic variable valve-lift control for the first time.

The cylinder block is made of aluminium whereas the pistons are of steel. Moreover, to reduce fuel consumption and emissions the brand has applied extremely thin, low-friction ‘Nanoslide’ coating to the interior of the cylinder wall. It also uses AdBlue technology, multiway exhaust-gas recirculation and near-engine exhaust gas after treatment to further reduce carbon emissions.

Codenamed OM656, this is a 2,925cc straight-six turbocharged diesel engine producing 335bhp between 3,600 and 4,400rpm while delivering 700Nm of torque from 1,200 to 3,200rpm.

M 256 - Petrol

Mercedes-Benz has begun electrifying its cars by developing hybrid powertrains such as the one paired to the M 256 inline six-cylinder petrol engine. This all-new engine is designed to incorporate a 48-volt mild-hybrid system. Moreover, there is an electric turbocharger, electric auxiliary compressor and an integrated starter-generator; all combined, it not only provides extra boost but also supplies power to the water pump, air conditioning compressor, lights, 12V sockets, infotainment system and various control units.

To put it simply, the integrated starter-generator ensures zero turbo lag while providing additional boost power before the primary turbocharger kicks in. It is also responsible for energy recovery by regenerative braking. This complete system also looks after the engine start/stop system. With this mild-hybrid technology, Mercedes-Benz has been able to reduce CO2 emissions by about 15 per cent in comparison to the previous generation V6 engine. The M256 is also more fuel-efficient at 12.34kmpl.

A 2,999cc straight-six twin-scroll turbocharged petrol motor is capable of generating 362bhp between 5,500 and 6,100rpm while delivering 500Nm of torque from 1,600 to 4,500rpm. The 48-volt electric motor provides an additional boost of 20bhp and a whopping 220Nm of torque.

Transmission

Both the six-cylinder engines are coupled with a nine-speed torque-convertor automatic. The brand calls it the 9G-TRONIC. Besides, this transmission ensures a smooth transition between the two gear shifts. The nine forward gears also help to keep the engine at lower rpm for better fuel efficiency. This fully electronically-governed gearbox also reacts to the various driving modes and changes its character accordingly.

Pioneering features

In 1981, Mercedes-Benz introduced seat-belt pretensioners in the S-Class. And now, roughly after three decades, the brand has showcased pioneering rear-seat frontal airbags technology. They are not just any ordinary airbags; because these airbags use ambient air and tubular structure to be packaged efficiently. With these airbags for the rear-seat passengers, the brand-new S-Class gets a total of ten airbags.

Another extraordinary feature of this sedan is its rear-wheel steering. Many cars have this feature, but the S-Class has taken it to the next level. The rear wheels can turn up to ten-degree either in the opposite direction of the front wheels or in the same direction. For instance, when the car approaches a roundabout the rear wheels turn in the opposite direction to reduce the turning radius, on the other hand, they move in the same direction, to help the car go faster around corners and maintain stability and steering precision.