In a pre-Frankfurt Motor Show announcement, Mercedes-Benz revealed its latest gasoline hybrid, the Vision (experimental/concept) S 500 Plug-in, a high-performance luxury sedan claimed to achieve a combined fuel consumption of 3.2 L/100 km and CO2 emissions of only 74 g/km in the NEDC cycle. It has the ability to travel for up to 30 km (19 mi) on electric power alone; it has a 44-kW hybrid module and a 10-kW·h lithium-ion battery.
Its internal combustion engine is a 3.5-L V6 with a next-generation fuel injection system. Performance figures for the Vision S 500 hybrid include 0-100 km/h (0-62 mph) in 5.5 s. The car is a precursor of a production version expected to appear in the model lineup of the next generation S-Class.
Mercedes-Benz’ boss Dr. Dieter Zetsche, said: “The Vision 500 Plug-in Hybrid is a new milestone on our path towards zero emissions mobility.” He said that, although a luxury car, it consumed less fuel than current compacts. “This shows that our top models will also be able to combine automotive fascination with responsibility for the environment.”
And Mercedes’ R&D Main Board member, Dr. Thomas Weber, added: “Although it will take some time before this model can go into series production, our engineers will be working full steam to carry out the necessary integration measures and ensure that all components can meet the tough everyday demands required of a luxury long-distance sedan. We’ve already got all the key technology we need for such a dream car, which is why I see it being included in the next generation S-Class.”
The S 500’s hybrid design echoes, in general terms, the compact, disc-shaped 15-kW electric motor of the S 400 hybrid, although it is almost three times more powerful.
For the S 500, the hybrid components can be incorporated into Mercedes’ 7G-Tronic seven-speed automatic transmission’s housing, obviating any intrusion into the S-Class’ interior. Other Mercedes models are to be based on the architecture.
The S 400 hybrid has its 0.9 kW·h battery tucked into the engine compartment but the much higher performance (10 kW·h) Vision S 500’s, needs more space and is positioned in the trunk behind the rear seats, which helps front:rear weight balance.
Compared to the S 400, the S 500 gets an additional clutch between the engine and electric motor, decoupling both in electric-drive mode.
The rapid charge cycle of the S 500 takes “less than 60 minutes” according to Mercedes. Charging capacity is 20 kW. A regular charge from a household socket with 3.3 kW takes around 4.5 h from total discharge to fully charged.
The battery is linked, via a dc-dc converter, to the car’s 12-V onboard network. Voltage transformers are water-cooled via a low-temperature circuit.
The car has an onboard charger in the trunk that controls the recharging process and is protected against short circuits, voltage reversal, and voltage surges. It monitors voltage, charge level, and charge time.
The inverter for the three-phase ac electric motor is positioned in the engine compartment and also shares the low-temperature circuit. The power electronics system uses standard components.
Weight is always a central issue with hybrid systems. Mercedes puts the total weight of the electrical components of the Vision S 500 at 215 kg (474 lb), with the battery weighing in at 130 kg (287 lb), saving at least 50 kg (110 lb) against a nickel metal hydride (NiMH) battery.
A regenerative braking system is used and the engine has a stop-start capability.
As well as the S 400 and S 500 hybrids, Mercedes has the Vision E 300 BlueTEC hybrid diesel, expected to be available in Europe in production form within two years. It uses the company’s new 2.2-L four-cylinder diesel engine—but producing 168 kW (225 hp) compared to the already highly efficient 150 kW (201 hp) of the current 250CDI—with the 15-kW hybrid module from the S 400 hybrid. The Vision E 300 BlueTEC hybrid can achieve a fuel consumption of 4.5 L/100 km, corresponding to emissions of only 119 g/km.