Driven: S500 Plug-In leads new Mercedes hybrid plan

MERCEDES-BENZ has kicked off its global plug-in hybrid electric vehicle (PHEV) rollout with the debut of its S500 Plug-In Hybrid limousine that sips less fuel than most light cars and is scheduled to be launched in Australia inside 18 months.

The German luxury car-maker’s first PHEV – one of 10 to be launched in the next three years, with others to follow by 2020 – goes in sale in Europe this month and starts a new chapter for the company, marking a shift in emphasis from mild to plug-in hybrid powertrains in an effort to meet stricter European emissions standards that come into force in 2020.

Speaking at the global launch in Germany last week, Daimler AG board member and head of Mercedes-Benz research and development Thomas Weber described the S500 Plug-In as the “spearhead” of the company’s hybrid strategy as it works to reduce its CO2 fleet average to 95g/km by 2020.

“The S500 Plug-In Hybrid marks a major step on our road to zero-emission mobility,” he said. “That is our clear objective. And on our way towards that goal we will adapt our fleet consumption to evermore tight CO2 emission limits.”

Described by Dr Weber as the “most efficient and intelligent S-Class ever”, the S500 Plug-In Hybrid matches a 245kW/480Nm 3.0-litre V6 twin-turbocharged petrol engine with an 85kW/340Nm electric motor for a combined output of 325kW/650Nm.

This is just 10kW/50Nm shy of the output of the regular S500 that is powered by a 4.7-litre V8, but while the PHEV sips just 2.8 litres per 100km on the official European combined fuel economy cycle – equivalent to 65g/km of CO2 – the non-hybrid version consumes 9.2L/100km and emits 215g/km.

Dr Weber said Mercedes is the leader in the luxury segment for environmentally conscious motoring, and highlighted the brand’s gradual reduction in fleet emissions over the past 20 years.

“We have massively reduced our CO2 fleet emissions in Europe: from 230 grams in 1995 to 134 grams last year,” he said.

“Average consumption has fallen by more than 40 per cent. The fact is that Mercedes-Benz is now the most efficient brand in the premium segment and has best-in-class figures for consumption in many vehicle classes.”

Dr Weber said there are no compromises when comparing the plug-in S500 with the internal combustion version, and that S-Class buyers will appreciate the benefits a hybrid drivetrain can bring.

“Our demanding S-Class customers do not want to make compromises. They expect the very best of driving fun, comfort and efficiency. And that is exactly what they get,” he said.

The S500 Plug-In Hybrid is set to arrive in Australia about the same time as the next model in the global rollout – the C350 Plug-In Hybrid – either late 2015 or early 2016.

Mercedes-Benz Australia/Pacific is keen for the hybridised S-Class to be priced identically to the regular S500 V8, which retails in Australia for $309,530 plus on-road costs in long-wheelbase guise (there is no short-wheelbase S500 Plug-In).

Mercedes-Benz Aust/Pac senior manager of public relations, product and corporate communications David McCarthy said that once compliance work is completed on the plug and cable to ensure it fits Australia’s power grid, it will be easier to introduce more plug-in models.

Mr McCarthy said that each new plug-in hybrid model Mercedes introduces in Europe will need to pass a business case to determine its viability for the Australian market, and added that the new hybrid strategy marks a shift from the company’s earlier plan.

“Our hybrid strategy to date has been diesel-based and the plug-in hybrids are a completely different matter,” he said. “The plug-ins that are coming are petrol. The reason for that is because the markets that are going to take this in the largest number prefer petrol.

“Over time that may well change, but for us it’s not a concern. We are happy where E300 hybrid is going, and S300 (BlueTec Hybrid), we are about to release C300 BlueTec Hybrid.

“Obviously we already make electric cars – the B-Class and the Smart (Electric Drive). We are a shareholder in (EV-maker) Tesla. So we are absolutely at the forefront of that technology”.

The only thing differentiating the hybrid and non-hybrid S500s is the badge on the bootlid identifying it as the S500 Plug-In Hybrid, and that is just how Mercedes wants it.

Perhaps unsurprisingly, no other car in its class comes close to the fuel consumption of the Plug-In, with Audi’s frugal A8 3.0 TDI diesel sipping 5.9L/100km, BMW’s 730d diesel drinking 5.6L/100km, while Jaguar’s XJ 3.0D consumes 6.1L/100km.

Interestingly, BMW’s ActiveHybrid 7 consumes 6.8L/100km and the Lexus LS600h V8/mild hybrid returns 8.6L/100km.

The S500 Plug-In features an 8.7kWh high-voltage lithium-ion battery that is replenished via a 3.6kW onboard charger, and the socket is hidden in the right-hand rear bumper. The battery is housed in a water-cooled storage unit and the whole set-up weighs a total of 114kg and has a volume of 96 litres.

Charging can take two hours with a wallbox at home or charging pole (400V, 16A), or a regular 230-volt connection can also charge the S500 in about two hours and 45 minutes.

A Mercedes-Benz executive said the Plug-In adds about 230kg of weight to the regular S500 LWB, which weighs in at 2015kg.

The inclusion of the battery pack in the rear of the car means luggage space is impacted, with the capacity dropping from 530 litres to 395L for the electrified S500.

Mercedes says the ledge created by the battery pack in the boot is the perfect size for carry-on-sized luggage, and the car-maker maintains that the S500 can still carry a couple of golf bags.

Performance-wise, the Plug-In can dash from zero to 100km/h in 5.2 seconds, which is only slightly slower off the mark than the V8-powered variant that covers the same distance in 4.8 seconds. Top speed is 250km/h, and in electric mode is restricted to 140km/h.

The big Benz has an electric range of 33km and an “intelligent operating strategy” helps the driver achieve optimal fuel efficiency.

Mercedes says an ‘intelligent operating strategy’ attempts to ensure that, where possible, the battery is depleted at the end of an uphill stretch so that it can be recharged on the downhill run, while the system also aims to ensure the battery is fully recharged when the vehicle reaches urban areas so that it can operate on electric mode in stop-start city traffic.

Other fuel-saving technology includes the haptic accelerator pedal that produces a double pulsing sensation when coasting, encouraging drivers to take take their foot off the accelerator to help recuperate energy.

The transmission is based on Mercedes’ 7G-Tronic Plus seven-speed automatic, and the parallel hybrid modular system the S500 uses features an additional clutch between the electric motor and combustion engine.

Our drive in the S500 Plug-In Hybrid around the streets of Stuttgart and the surrounding countryside offered a mixture of conditions to test the car’s petrol-electric drivetrain.

Inside, there is no real difference to the regular S500, save for a couple of extra hybrid-related displays on the massive digital instrument cluster.

The seats up front and in the back feel like they are made for royalty, and the cabin offers copious space for all occupants. We tested a number of settings on the massage function and can give it two big thumbs up.

Standard gear includes pre-entry climate control that includes heating or cooling of the air, seats, steering wheel, armrests and centre console prior to getting into the car.

LED headlights and tail-lights, leather upholstery, Comand online connectivity system, ambient lighting, Airmatic air suspension and a touchpad are all standard, while the Pre-Safe system, Collision Prevention Assist that includes adaptive braking, a fatigue warning system, cross-wind and traffic sign assist are also included.

The W222 S-Class offers a comfortable, calm and quiet ride and the inclusion of hybrid power has enhanced this even further. Whisper-quiet on take-off, there is a subtle noise when the petrol V6 kicks in on harder acceleration, but it is smooth and less intrusive than some other hybrids we have driven.

In fact, when coasting, the only noise we encountered was the occasional bump when travelling on pot-holed streets.

The addition of a hybrid powertrain has done nothing to diminish the plush ride of the S-Class, and the extra weight is barely noticeable. While the Plug-In is slightly slower off the mark than the V8, most buyers would not notice, or care.

The sheer size of the S-Class means it is not the most agile car when cornering – bodyroll is apparent and the suspension set-up makes for a supremely cushioning ride that is expected in a vehicle of this ilk.

In the end, our fuel consumption reached 7.9L/100km, and while this is well above the 2.8L/100km official rating, it was due to some spirited driving via a combination of city, highway and country driving in both electric and petrol modes.

Hybrid power does not appeal to everyone, and buyers that can afford a $300,000-plus luxury limousine may not be too fussed about saving a few dollars at the petrol pump.

But the technology in the S500 Plug-In Hybrid is impressive, the ride is sumptuous and the only real downside is the reduced luggage space.

But if you can live with a few less available litres in your boot, and if Mercedes-Benz Australia can bring the S500 Plug-In here at the same price as the V8, it could be worth checking out.