Mercedes-Benz Details Plug-in Hybrid S-Class Sedan

Daimler AG's Mercedes-Benz unit has released details about the S 500 BlueTEC plug-in hybrid luxury sedan it will begin delivering this month.

The big sedan promises a net 436 hp and 479 lb-ft of torque, acceleration from zero to 100 kph in 5.2 seconds and the ability to drive 20 miles in electric-only mode.

The car is certified under the optimistic New European Driving Cycle at 2.8 liters per 100 km (84 mpg U.S.) and 65 grams of carbon dioxide emissions per kilometer.

The S 500 plug-in's modular powertrain consists of a 3.0-liter V-6 bi-turbo gasoline engine rated at 333 hp and 354 lb-ft of torque and an 85-kW electric motor that makes 251 lb-ft of torque. The car carries a 250-lb water-cooled 8.7-kWh lithium iron-phosphate battery capable of delivering between 270 volts and 430 volts, depending on operating demands.

The car uses a modified version of Daimler's 7-speed automatic transmission. An addition clutch enables the gearbox to decouple the piston engine when the powertrain is operating in electric mode.

A 3.6-kW onboard charger replenishes the battery. Mercedes says charging can be accomplished in two hours with a 400-volt, 15-amp connection. A European household connection (230 volts and 13 amps) takes an additional 45 minutes.

The powertrain is designed to launch the car in electric mode, turn on the piston engine when needed for extra power and revert to electric-only propulsion whenever possible. The engine automatically switches off whenever the vehicle is coasting. The driver can select among four increasingly aggressive eco modes, plus three transmission modes including one that locks out the pure electric mode.

A second-generation recuperative braking system uses the electric motor for initial braking before seamlessly activating the mechanical wheel brakes. A haptic accelerator pedal signals the driver with a double pulse to suggest when to allow the car to coast or use regenerative braking.

Mercedes says the S 500 plug-in's engine can be used to full charge the onboard battery in about 30 minutes. To help optimize efficiency, the car's energy management system can use the navigation system to calculate an optimal all-electric, charging and recuperative operation strategy.