Hybrid Car Review: 2015 Mercedes Benz S550 Plug-in Hybrid

This is an automotive column at Examiner.com written by Sebastian James, publisher of Hybrid and Electric Car News. Enjoy, and be sure to subscribe to his posts.

The car in the video above is the 2015 Mercedes Benz S550 Plug-in Hybrid sedan.

S-Class. Plug. In. Hybrid.

It’s not a joke.

It’s not the end of the world.

Nor did you see pigs with wings.

And that wasn’t a monkey, it was the burrito you had for lunch yesterday.

A vehicle like this invites comments about affluence, affordability and various problems of the top 1% of the First World. Does anyone need an S550 PHEV? No. Do they need an S550? Again, no.

But if a person can afford to pay for an S550, if they can afford to own one, and they want it to be a 5,100 lb., 7-speed automatic, 6-cylinder V-6 that generates 436 horsepower with 479 lb./ft of torque that gets an unofficial 21 mpg; then THIS is their new Mercedes Benz S-Class.

2015 Mercedes Benz S550 PHEV, 3/4 front view

This new battleship is the leader of a small flotilla of S550’s with different powertrain combinations. Mercedes had introduced gasoline, diesel and hybrid variants in previous years. This is the first year for a plug-in hybrid.

The Euros are starting to move towards America when it comes to hybrid technology. No one likes to pay for fuel, and their prices are even higher than ours.

My belief is that the trick with getting Europeans to embrace hybrids–especially plug-ins will be a combination of performance AND making it easy to charge. Performance-wise, 479 torques means 0-62 in 5.2 seconds. Ease of charge? According to Mercedes, the 2015 S550 will take about 4 hours to reach full charge from a standard wall socket. They say it will take under 3 from a 230-volt outlet:

The new S-Class can be charged in two hours anywhere in the world, e.g. at a wallbox or a charging pole (400 V, 16 A). Alternatively, charging via house connection is also possible. Depending on the connection a charge time e.g. of two hours and 45 minutes can be attained (with 230 V and 13 A). The operating data from the charge process and the available output are continuously transmitted to the vehicle’s energy management system, which then controls the charge process. The on-board charger is located near the battery to ensure the optimal length of connecting cables and cooling water lines.

Their engineers are working on a wireless induction charging station. It’s not ready to roll out yet. Wealthy Euros everywhere could literally park the car over a pad and it will recharge wirelessly.

Charging the 2015 Mercedes Benz S550 Plug-in Hybrid

But if they had to actually physically take action to charge the car, access to the battery is through a small flap just above the bumper hiding the socket. The socket leads to a trunk-mounted, water-cooled, 250-pound battery. The bulk of all of this cuts boot storage to 12.2 cubic feet. To stop unauthorized charger detachment, the connection can only be unlocked by the key holder.

2015 Mercedes Benz S550 Plug-in Hybrid Engine Compartment

“The S550 PLUG-IN HYBRID is the first luxury sedan with the performance of a V8 and the fuel consumption of a compact model. The greatest challenge in this is to translate efficiency into superior performance. In this respect there is a highly interesting parallel with our successful Formula 1 racing car, which likewise has a turbocharged V6 engine and a high-tech hybrid drive,” says Prof. Dr. Thomas Weber, member of the Daimler Board of Management responsible for Group Research and Mercedes-Benz Cars Development.

Although the official stats have yet to be released, our friends at Car and Driver unofficially say the S550 achieved 21 mpg during their first drive. Not necessarily the consumption of a compact car, but significantly better than that of a rank-and-file S-Class.

Here are some of their thoughts on the hybrid power plant:

The 114-hp electric motor is integrated inside the seven-speed automatic, and it is powerful enough to propel this S-class to 87 mph on electricity only. Using a light touch on the accelerator, it can go for 20 miles on a full charge before the direct-injected, twin-turbocharged 329-hp V-6 kicks in. We estimate that the hybrid powertrain will hurl the big Benz to 60 mph in 5.2 seconds. Top speed is governed at 130 mph for the U.S., but it’ll do 155 mph in Europe.

Before we go farther, let’s talk about the electric motor. Usually these are mounted near the gasoline engine. Some, like Porsche, are mounting electric motors directly to each wheel, depending on the drive configuration.

2015 Mercedes S550 Plug-in Hybrid Nameplate

In the case of the S550, Mercedes decided upon a slightly different approach. They have mounted a small clutch in between the diesel and the electric motor. Here’s what their engineers have to say:

On the one hand, it decouples the combustion engine during purely electric operation; on the other hand, if the combustion engine is employed it affords the possibility to move off drawing on the performance of a wet start-up clutch. The clutch then substitutes for the torque converter and requires no additional space owing to its complete integration in the torque converter housing.

2015 Mercedes Benz S550 Plug-in Hybrid, turning

There are mixed reviews on how the additional technology and weight impacts the ride and road comfort of the S550. Car and Driver thought the additional 650 pounds made the car “cumbersome” in the corners. When the people at Autoweek.com took the S550 for a spin, they were a bit more generous:

Just like the standard S-class, the Hybrid rolls over bumps as if they were soft pillows in the road. Even in sport suspension mode, we still felt coddled by the air spring, single-tube shock, multilink setup. It didn’t feel quite as stiff as the standard S550, which corners amazingly flat when driving “enthusiastically.” The steering is suitably smooth for a big sedan like this, so don’t look for a ton of feel.

2015 Mercedes Benz S550 Plug-in Hybrid Intelligent Drive Panel

To help squeeze as much economy as possible out of the powertrain, Mercedes engineers have devised something called the Intelligent Operating Strategy. It is a combination of onboard cameras, engine and transmission computers linked to steering and the accelerator pedal. You saw some of this in action in the MotoMan video linked to this article. He called it ‘Magic Vehicle Control’. Here’s how Mercedes describes it:

In the background, the intelligent operating strategy automatically selects the ideal combination of internal combustion engine and electric motor and in so doing not only adapts its strategy according to the charge status of the battery; in transmission mode E+ it also foresightedly adjusts it according to the traffic or route. But anyone wanting to can also intervene manually and with the aid of four operating modes and three transmission modes regulate the hybrid interplay themselves. Here, what is known as the haptic accelerator pedal supplies the driver with feedback on the switch-on point of the combustion engine or signals via a double impulse when they should take their foot off the accelerator for sailing and recuperating.

You read that right. Or if you don’t know what ‘haptic’ is, read on. Based on the driving mode you’re in, the accelerator pedal of the 2015 Mercedes Benz S550 will vibrate, telling you the optimal time to take your foot off the gas. It will also give you a physical cue when not to push on the pedal as well.

Wives and parents are rejoicing worldwide. Finally, the car will be able to tell men and teenagers to slow down.

Here’s a closer look at each driving mode:


Hybrid: As the name indicates, this standard mode offers hybrid driving, i.e. combines the operation of electric motor and combustion engine. The extent to which the electric motor is used to optimize consumption, or with boost function for especially dynamic acceleration, depends – apart from the customer’s driving style – on the battery charge status and the chosen transmission mode.

E-mode: In this operating mode the S550 PLUG-IN HYBRID runs purely electrically as much as possible. To ensure that the driver does not inadvertently engage the combustion engine by stepping on the accelerator, the haptic accelerator pedal with pressure point is automatically activated in this mode. The combustion engine engages only when the driver overcomes the pedal’s distinct pressure point.

E-save: Here the charge status of the battery is preserved as it was when this operating mode was activated. For example, a fully charged battery can be held available if purely electric driving in a big city is on the agenda later. Electric driving in especially favourable situations, for instance after brief stops, is still permitted, but is metered so that the charge status does not fall below the value set by pressing the button.

Charge: Here the high-voltage battery is charged during vehicle operation with the aid of the internal combustion engine. Electric driving and boost operation are completely dispensed with. Under optimal conditions a run-down high-voltage battery can be fully charged in just about half an hour.

2015 Mercedes Benz Plug-in Hybrd, side view

Back in 2008 or 2009, GM decided to bolt a hybrid engine in a Cadillac Escalade. The idea was a ham-fisted attempt at trying to look ‘green’ while achieving a fleet mileage figure. It failed in terms of being taken seriously by the market.  Since then attempts to create a green flagship sedan or SUV have met with a range of similar results.

Time will tell if the 2015 Mercedes S550 PHEV breaks the cycle of failure. The new vehicle will go on sale in California in 2Q 2015, and the rest of the US as a 2016 model year vehicle.




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Copyright 2014 Hybrid and Electric Car News



Sebastian James


Accept no substitutes

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