The Geneva Motor Show will see the debut of two new Mercedes-Benz preproduction models that combine state-of-the-art diesel technology with the 9G-TRONIC 9-speed hybrid transmission. Until 2022 there will be 50 vehicle varieties with electric engines in the portfolio of Mercedes-Benz. Delivery of the first models is scheduled for late summer 2018.
Plug-in hybrids offer customers the benefits of two worlds: in town, they run in all-electric mode, while on long journeys they profit from the range of the combustion engine. Mercedes-Benz will for the first time combine the state-of-the-art four-cylinder diesel with the third-generation hybrid drive. The result: even higher efficiency, remarkable ride comfort and dynamic performance as well as an impressive range.
Soon to launch: plug-in diesel hybrid in C- and E-Class
As the strengths of plug-in hybrids come to the fore, especially in larger vehicles and on mixed route profiles, Mercedes-Benz is now opting for this powertrain concept from the C-Class upwards. Mercedes Benz will for the first time pair its state-of-the-art diesel engine with an externally chargeable hybrid system. Like the S 560 e (combined fuel consumption 2.1 l/100 km, combined CO2 emissions 49 g/km) , the C- and E-Class plug-in diesel hybrids will in future use third-generation hybrid technology.
The combination of the new OM 654 four-cylinder diesel engine with the latest-generation 9G-TRONIC 9-speed hybrid transmission promises to enhance the experience of locally emission-free mobility while at the same time offering emotively appealing driving pleasure.
The new on-board charger doubles the charging rate. A discharged battery can thus be fully recharged in two hours at a wallbox, for example in the convenience of one's own home. This is possible within around seven hours even at a conventional domestic power socket.
State-of-the-art diesel: OM 654
The new plug-in diesel hybrids in the C- and E-Class will share the new OM 654 four-cylinder diesel engine. This ultra-modern engine family opens up new dimensions in efficiency. It is the first passenger car diesel engine to use the stepped-bowl combustion process – named after the shape of the combustion bowl in the piston. The innovations also include the combination of an aluminium engine block and steel pistons, as well as the further-improved NANOSLIDE® coating of the cylinder walls. The internal friction has been reduced by around 25 percent.
On top of this, the engine is also more compact than its predecessor. All components relevant for efficient emissions reduction are installed directly on the engine. Thanks to the near-engine configuration, exhaust aftertreatment has a low heat loss and excellent operating conditions.
Third-generation hybrid drive: more powerful, more compact
The third-generation hybrid transmission is based on the 9G-TRONIC automatic transmission. The torque converter, clutch and electric motor are housed in the innovative hybrid drive unit. The compact design was achieved by integrating and connecting the separating clutch, torsional vibration damper and torque converter lockup clutch within the rotor of the electric motor. The torque converter with its powerful and highly efficient hydraulic circuit offers the customary smoothness when pulling away in hybrid mode. Developed together with Bosch as part of the EM-motive joint venture, the electric motor was specially designed for the 9G-TRONIC plug-in hybrid transmission. The equally new power electronics have allowed further increases in output and torque compared with the second generation.
Intelligent operating strategy with ECO Assist
The new hybrids provide the driver with comprehensive assistance in terms of predictive driving and fuel-saving: the driver is prompted when appropriate to come off the accelerator and assisted by innovative functions such as coasting and energy recovery. For this purpose, navigation data, traffic sign recognition and information from the intelligent safety assistants (radar and stereo camera) are linked and processed. The haptic accelerator helps the driver to achieve an economical and comfortable driving style. A variable pressure point in the pedal, for example, tells the driver that the maximum electric power is being delivered. If the driver continues to press the pedal beyond the pressure point, the combustion engine kicks in. A perceptible resistance in the haptic accelerator advises the driver to take their foot off the accelerator. If the driver follows this recommendation, the combustion engine is switched off and decoupled from the powertrain.
Within the limits of the system, ECO Assist controls the overrun mode according to the situation as soon as the driver takes their foot off the accelerator. The driver is also given a visual prompt to do this. At the same time, a diagram gives the driver the reason for the recommendation.
Performance to suit the driver's wishes: four hybrid modes
Depending on the driver's wishes, four operating modes can be preselected. They are:
• HYBRID: Default setting; all functions, such as electric driving, boost and energy recovery, are available and used according to the driving situation and route profile
• E-MODE: Electric driving, for example in the city centre. The accelerator signals the pressure point at which the combustion engine is started
• E-SAVE: The charged battery is held in reserve to allow driving in all electric mode later
• CHARGE: The battery is charged while driving.