Merc readies strategy to go green with smaller, more powerful engines

The prospect of more stringent emissions regulations and, of course, the massive trend towards electric and hybrid engine technology is driving car manufacturers to develop new engine lines. If future-proofing was the buzz word sometime ago, today that future is already upon us and so new engines planned for the next few years will have to be compatible for accommodating a possible hybrid powerplant immediately after.

Mercedes-Benz is one of the early announcers of its strategic engine initiative. Said to be the biggest in its history, the German luxury car brand will launch a slew of new powertrains in 2017.

After the launch of the new 4-cylinder diesel engine in spring 2016, next year will see the addition of four more members to the all-new family of engines: six-cylinder in-line engines in both diesel and petrol versions, a new 4-cylinder petrol engine and a new biturbo V8. An official statement from Mercedes mentions that there will also be world premieres for ground-breaking technologies, such as the Integrated Starter-Alternator (ISG), the 48 V electrical system and the electric auxiliary compressor (eZV).

The new six-cylinder in-line petrol engine represents an outstanding example of electrification, including a 48 V electrical system. New, intelligent turbocharging eg., with an electric auxiliary compressor (eZV), as well as an Integrated Starter-Alternator (ISG) provide the guarantee of drivability with no turbo lag. The ISG is responsible for hybrid functions, such as boost or energy recovery, while allowing fuel savings that were previously reserved for high-voltage hybrid technology. According to Mercedes-Benz, the bottom line is that the new six-cylinder in-line engine offers the same performance as an 8-cylinder mill while being much more fuel-efficient. The new petrol engine (internal code: M 256) launches next year in the new S-Class.

The 48 V electrical system serves not only high power consumers, such as the water pump and air-conditioning compressor, but also the Integrated Starter-Alternator (ISG), which also supplies energy to the battery by means of highly efficient energy recovery. In comparison with the previous V6, the CO2 emissions from the engine have been reduced by around 15 per cent.

The new top-of-the-line engine in the premium diesel family is likewise a six-cylinder in-line unit. The characteristics of the OM 656 include the stepped-bowl combustion process, two-stage exhaust turbocharging and, for the first time, the use of CAMTRONIC variable valve timing. Its design features a combination of aluminium engine block and steel pistons as well as a further-improved coating of the cylinder walls. Although there is a significant increase in output compared with the previous OM 642 (over 313 hp instead of 258 hp), the new engine’s fuel consumption is over seven per cent lesser.

Like the already unveiled four-cylinder OM654, the new six-cylinder diesel engine OM 656 is likewise designed to comply with future emissions legislation.

The Mercedes-Benz release also talks about the new V8. Said to combine power delivery with high efficiency the new biturbo (internal code: M 176) is claimed to be one of the most economical V8 petrol engines in the world. Its special features include cylinder shutoff at part load as well as the positioning of the turbochargers in the V between the cylinder banks. From its 3,982 cc displacement, the new V8 biturbo produces over 476hp with a maximum torque of around 700Nm from 2,000 rpm. The new engine’s fuel consumption is about 10 per cent lesser than its predecessor, which is rated at 455 hp. The new V8 will launch with this technology next year in the new S-Class.

For lower fuel consumption, when operated at part load the new M 176 shuts off four cylinders simultaneously by means of CAMTRONIC valve timing. This reduces the pumping losses while improving the overall efficiency of the remaining four cylinders by shifting the operating point towards higher loads.

Many luxury car makers are investing in high-tech 4-cylinder engines and Mercedes joins in with this new two-litre unit. This engine with a specific output of around 100 kW is the new Top-type petrol engine from Mercedes-Benz (internal code: M 264). This unit explores into output regions previously reserved for high-displacement six-cylinder units and at the same time consumes significantly less fuel than a comparable six-cylinder engine says the Merc release. The engine's special features include twin-scroll turbochargers, belt-driven 48 V starter-alternator (BSA) and electric 48 V water pump.

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