Frankfurt Auto Show: Mercedes developing plug-in hybrid

    Mercedes-Benz Vision S500 Plug-In Hybrid Concept

Mercedes-Benz has offered a peek into its future at the Frankfurt Auto Show with a car it calls the Vision S500 Plug-In Hybrid Concept.

The full-size S-Class sedan combines a 3.5-liter V-6 engine, presumably the same 275-horsepower powerplant that is in the recently introduced S400 Hybrid, with a 60-horsepower electric motor.

Unlike the S400 mild hybrid, which does not operate on electrical power alone, the S500 Plug-In can travel up to 18.5 miles on a single charge of its 10-kilowatt-hour lithium-ion battery pack.

In other respects, the powertrain design for the Vision S500 Plug-In is basically the same as the S400 Hybrid. The electric motor is located between the engine and the 7-speed automatic transmission. Under full power, the engine/motor combination can accelerate the Plug-In from a stop to 60 mph in less than 5.5 seconds.

The German manufacturer says recharging of the S500 hybrid will take 4 1/2 hours from a standard household outlet, 60 minutes from a 20-kilowatt-hour source.

The battery also is charged through regenerative braking, which turns the car’s alternator into a generator when it is coasting and braking. The powerplant shuts down when the car is stopped for a traffic signal and restarts automatically when the driver’s foot moves back to the accelerator.

Mercedes-Benz officials did not indicate when the S500 Plug-In Hybrid would go into production but Dr.Thomas Weber, a member of the management board, said “I see it being included in the next generation of the S-Class.”

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