Frankfurt show: Mercedes plugs into S-Class fuel miser

MERCEDES-Benz has released details of a plug-in hybrid S-Class saloon that sips about the same amount of fuel as a motor scooter.

The petrol-electric S500, sipping just 3.0 litres of fuel for every 100 kilometres it travels, will make its debut at next month’s Frankfurt motor show.

It follows on from the 4.4L/100km S300 BlueTec Hybrid and 6.6L/100km S400 Hybrid featuring diesel-and petrol-electric drivetrains, but the range-topping S500 is the first plug-in hybrid model in the S-Class family.

Mercedes-Benz Cars Australia is said to be looking into the S500 Plug-In Hybrid for the Australian market, but it is believed that variant is not the top priority for the local S-Class line-up. However, if it does get the green light, could appear several months after the launch of the rest of the range in December.

The S500 Plug-in Hybrid combines a 245kW/480Nm 3.0-litre turbo V6 petrol engine with an 80kW/340Nm electric motor, and is capable of an electric-only driving range of just under 30km.

Mercedes claims the S500 Plug-In generates 69 grams of carbon dioxide per kilometre – making it better for the environment than a Toyota Prius – and says the 3.0L/100km fuel use figure “sets a new benchmark for luxury saloons that just a few years ago was thought virtually impossible”.

The lowball fuel figure also puts Mercedes-Benz well ahead of some of its main competitors, including BMW’s petrol-electric ActiveHybrid 7 which combines a 3.0-litre in-line six-cylinder engine with an electric motor for fuel economy of 6.8L/100km, while Japanese luxury brand Lexus’ V8-engined hybrid LS600h produces an official figure of 8.6L/100km.

Mercedes-Benz says the high-voltage lithium-ion battery in the S500 has 10 times the energy content of batteries in the S300 and S400 and can be charged by an external source, as well as via the V6 engine.

The car-maker says the batteries in both the S300 and S400 Hybrid models are charged by the combustion engine while braking or coasting.

The driver can choose from four hybrid driving modes in the S500 plug-in, including hybrid, electric-only 'E-Mode', 'E-Save' which maintains a fully charged battery for use at a later time, and 'Charge' which charges the battery while driving.

The combined petrol-electric power pushes the S500 from 0-100km/h in 5.5secs, not quite as quick as the non-hybrid 4.7-litre V8 S500 that covers the same distance in 4.8secs. Top speed is 250km/h.

All three hybrid models in the 2013 S-Class range feature an “anticipatory engine management system” that uses navigation data to map out the likely route for eight kilometres, as well as taking into account the current driving conditions.

The system then determines the section of the route that is the most appropriate time to recharge the battery, such as on downhill runs.

To further improve fuel efficiency in the big limo, Mercedes uses a haptic accelerator pedal that provides the driver with feedback about when the combustion engine will kick in.

More details, including final Australian specifications and pricing are due closer to the S-Class range’s December launch date.