2018 Mercedes-Benz S-Class adds hybrid in-line six options

MERCEDES has revealed a second version of its all-new electrified in-line six-cylinder engine will join the refreshed S-Class range, packing a more conservative but still juicy 270kW.

The German car maker also confirmed a 320kW version of the same engine will also be offered as part of the mid-life S-Class line-up, as previously revealed by Wheels in June.

Until fresh S-Class information emerged, the new straight-six unit had only been detailed in its most potent form for the S-Class and Mercedes-AMG CLS 53, but it’s now clear the engine is more versatile than originally revealed.

With at least two states of tune, the spicy but frugal electrically boosted straight six looks set to proliferate the Mercedes range with a number of different power outputs potentially applying to a wider range of vehicles, with the AMG CLS and S-Class already lined up.

Under the bonnet of the CLS 53 the turbocharged M256 will pump out 320kW – and an undisclosed amount of extra torque – but can tap another 50kW from an electric motor when needed.

However, under the bonnet of the more comfort and efficiency focused S-Class, the hybrid six works differently.

Under petrol power alone, the S500’s six-pot produces 320kW and 520Nm. Its electric booster adds just 16kW but a hefty dose of torque: 250Nm. Compared with the previous V8-powered S500, the new electrified version cuts CO2 emissions by 22 percent, but equals its power.

The size of the powertrain is made smaller by combining the role of alternator, starter and drive motor into just one unit, while most of exhaust gas and emissions control hardware has moved to under the bonnet.

With the advent of high-energy electrical consumers including drive motors, active suspension and electric compressors, Mercedes will introduce a higher voltage electrical system with the new hybrid drivetrain, but while others including Audi have opted for a more standardised 48-volt approach, the new Mercedes six runs a 49-volt system – according to the official press release.

Australian specifications are yet to be finalised ahead of the six-cylinder S-Class’s arrival late this year, but given the German brand’s local portfolio trend, it is possible only the more potent S500 version will be offered, while the S450 will remain the preserve of European and other global markets.

Despite the impressive performance from just 3.0 litres, Mercedes reports that the large sedan will still return an average fuel use figure of between 6.6-7.0L/100km depending on the variant.

In Europe’s diverse and variant spread-friendly market the S-Class sedan will be offered in 24 versions covering a number of combinations of rear and 4Matic four-wheel drive, long and short wheelbase as well as a choice of badges from the AMG and Maybach stables.

Australia will take a slimmer range which currently extends to 12 options including Mercedes-AMG and Mercedes-Maybach options.