First Drive: Mercedes’ C 350e plug-in hybrid

The Mercedes-Benz C 350e is the tip of a very big iceberg.

This new version of the C-Class sedan is only the second plug-in model from Mercedes. It goes on sale this September behind the S-Class plug-in that’s hitting dealerships now.

But by 2017, Mercedes plans to have 10 plug-in hybrid cars and SUVs on the market as part of what it calls the “hybrid offensive.”

Mercedes isn’t the only luxury European brand falling in love with the plug-in hybrid. Over the next several years, Audi and BMW will also use plug-ins to diversify their lineup of green vehicles beyond just diesel engines.

The reason is twofold: diesels have yet to gain the respect in the U.S. that they command among European luxury buyers. And plug-in hybrids -- which have gas-powered engines but can also run purely on electric power -- emit less CO2 than diesels. This gives plug-ins a crucial advantage as cities and countries crack down on emissions.

“Plug-in hybrids are a key technology on the road to the local emissions-free future of the automobile,” Thomas Weber, head of research and development for Mercedes-Benz, said while announcing the C 350e. “Plug-in hybrids offer our customers the best of both worlds.”

If those worlds are performance and efficiency, the C 350e has them covered.

It’s powered by a 1.9-liter turbocharged four-cylinder engine and an electric motor. Total power is 275 horsepower and 443 pound-feet of torque. A seven-speed automatic transmission pushes power to the rear wheels.

The C 350e can do zero to 62 mph in 5.9 seconds, which makes it slower than the C 400, but faster than the base gas-powered C 300 sedan.

That’s notable because it’s also heavier than the C 300 -- about 500 pounds heavier, thanks largely to the addition of the 60 kW electric motor and the lithium batteries.

Those batteries are loaded into the floor of the trunk, eating up less than a cubic foot of cargo room. As an added bonus, Mercedes kept the fold-down rear seats, a neat trick many other hybrid sedans lack.

The batteries recharge fully in about 90 minutes with a 220-volt outlet or three hours with a conventional 110-volt outlet, Mercedes said. The C 350e can travel about 19 miles on electric power alone before kicking on the gas engine to power the car and to recharge the batteries.

The batteries also get recharged through an innovative trick that uses the car’s radar to detect a slower-moving car ahead of it. When it does and the driver is accelerating, the C 350e will send two subtle pulses through the gas pedal. This alerts the driver to take his foot off the accelerator, after which the Mercedes automatically slows down to the same speed as the car ahead, and in the process recharges the batteries.

We spent half a day driving the C 350e in and around San Francisco. We started with about 13 miles of electric-only range and after just under eight hilly miles of stop-and-go traffic, we had depleted them. Under pure EV power, the car had plenty of smooth, silent get-up and made for easy driving around the busy city streets.

The car’s transition from electric power to gas was seamless, though you could definitely hear the engine turn on. It runs a little rougher than we’d hope for something wearing a Mercedes badge, but the car still packed much of the segment-leading refinement we were smitten by when we tested the base C 300.

The car has various drive modes that affect how to mix the electric and gas power. In any of them, the car had good pickup from a dead stop. Drivers won’t mistake it for the more assertive twin-turbo V-6 in the C 400, but the C 350e blends performance and efficiency well.

With dozens of cities throughout Europe adopting rules that allow only zero- or low-emissions vehicles to enter city limits, plug-ins like this C 350e have features that make sure the car is prepared to enter a city with a full battery to drive on electric power only.

The Mercedes has a feature that will use the gas engine to fully charge the batteries while driving to maximize its electric-only range once inside the city limits. Drivers can also tell the C 350e to save its current state of charge and rely only on the gas engine.

The car also has a pair of stout sport modes that we relished on open, winding roads. These settings progressively firm up the car’s suspension and steering, quicken the gear changes and sharpen the throttle response.

After about 70 miles of driving in a variety of conditions, we averaged a very respectable 32.2 mpg.

Mercedes hasn’t confirmed the base price of the C 350e, but it will likely start between $43,000 and $45,000. That’s at least $3,700 more than the cheapest C 300, a reasonable jump considering the added technology.

This won’t be the only green C-Class Mercedes will offer. Next up in this compact sedan family will be the C 250 diesel, which will serve as the entry point for the C-Class lineup when it goes on sale, likely by 2016.

The next plug-in hybrid on the docket is the GLE, Mercedes’ mid-size SUV that was formerly known as the ML. Look for it later this year as the automaker continues its plug-in hybrid onslaught.

In the meantime, Mercedes hit the sweet spot it was aiming for with the C 350e. It blends efficiency and performance in a compelling package that will suit a wide range of buyers both in the U.S. and abroad. It’s a promising tip of that very large iceberg.