Following the S400 hybrid which successfully turned from a concept into a real car, Mercedes is launching another identical project, this time time the S500 plug-in hybrid. Although it’s called S500, the petrol engine in this car is a 3.5 liter V6 which is combined with a lithium-ion battery and of course an electric motor from the hybrid module. This will result in fuel consumption of only 3.2l/100km and 74g/km of CO2 which are astonishing numbers considering the size and class of the car.

The high-performance battery and the 44 kW/60 hp Hybrid module enable the vehicle to drive up to 18 miles purely on electricity. That is completely sufficient for many trips within cities, where the Mercedes-Benz S500 Plug-in Hybrid Concept is quick and very comfortable without producing any local emissions. The gasoline engine automatically adds its power to that of the electric motor when travelling at high speeds or driving up steep inclines. Before closing the clutch in such cases, the vehicle electronics synchronises the engine speed with the Hybrid module’s rotational speed so that the engine is activated extremely smoothly without the driver noticing.

The lithium-ion battery not only serves as an energy storage device for the elec-tric motor in the Mercedes-Benz S500 Plug-in Hybrid; it is also linked via a DC-DC converter to the 12-volt on-board network, which provides power to standard consumers such as the headlamps and various comfort devices. To ensure a consistently high level of electrical efficiency, the voltage transformers are water-cooled via an additional low-temperature circuit.

Special power electronics are required for operating the three-phase AC electric motor in the high-voltage direct current grid, and the inverter for this task is hou-sed in the engine compartment. Because the power electronics system itself is heated by the electric current thus created, it too is integrated into the low-temperature cooling circuit. Mercedes-Benz employs standardized components for the power electronics system as well, enabling them to be efficiently com-bined with different electric motors and battery types across all model series.

Mercedes-Benz S500 Plug-in Hybrid Concept – Technical Data

• Combustion engine (gasoline)
  • No. of cylinders/arrangement: V-6, 4 valves per cylinder
  • Displacement: 3.5 l
• Hybrid module
  • Type: Permanently excited synchronous machine
  • Rated output: approx. 44 kW/60 PS
  • Rated torque: 184 lb-ft
• Performance and fuel consumption
  • Acceleration 0-60 mph: 5.4 s
  • Top speed: 155 mph (250 km/h)
  • Fuel consumption: 3.2 l/100 km (combined)
  • CO2 emissions: 74 g/km (combined)