After teasing us with a E400 BlueTEC hybrid years ago at NAIAS, Mercedes once again introduced new plug-in DIESEL hybrids at the Geneva Auto Show earlier this month.  Will this be the next frontier of powertrain design?

For a variety of different reasons that we won’t get into here, fully electric cars are not yet an option for mainstream, mass-market use.  However, increasingly strict emissions regulations on NOx and CO2 have respectively made traditional diesel and gasoline powered vehicles harder to engineer, never mind the possibility of outright bans on traditionally powered vehicles in cities like London.  A plug-in hybrid seemingly bridges this gap – allowing the benefits of electric drive immediately today without the limitations that all-electric drivetrains have with current technology.

The new diesel plug-in hybrids will be introduced on the C-Class and E-Class in Europe by the end of 2018.  The drivetrain package is designed to scale up, and may be introduced into larger sedans and commercial vehicles later on.  These models will also incorporate all the Mercedes fuel-saving technologies, such as ECO Assist.

Mercedes has long been the worldwide leader in diesel engine technology, so it is exciting to see them combine their diesel dominance with advanced drivetrains.  These new diesel-hybrid models will use their state of the art OM654 engine, which we reviewed in an earlier article.  This engine includes a wide range of technology upgrades to drastically improve efficiency and reduce emissions.

This all new engine gets combined with Mercedes’ new, third-generation, hybrid system.  This 3rd gen system utilizes a 90kw electric motor powered by a 13.5 kWh lithium-nickel-manganese-cobalt battery, which has twice the capacity at the same size as Mercedes 2nd generation hybrid battery.  Being a plug-in hybrid, these new vehicles can be charged at home using a Mercedes-Benz “wallbox”. Fully charged, the new C and E-Class diesel hybrids can travel up to 30 miles on electric power alone.

The whole drivetrain intersects in the new Mercedes 9G-TRONIC transmission.  The electric motor exists and takes the place of the traditional clutch and torque converter design, resulting in a very compact overall hybrid package.  Additionally, the high voltage system allows things like electric steering and impressively an electrically driven air conditioning compressor. Taking both of these things off the accessory belt system will further improve fuel efficiency.

Combining a state of the art diesel engine & newest generation electric drivetrain should result in a very impressive vehicle.  While fuel economy numbers are not released yet, Mercedes is advertising that the combined torque both vehicles will be around 516 ft/lbs.  This won’t be a slow drivetrain, and the combination of electric motor and torquey diesel will make driving these models a really enjoyable experience.

Pricing for Europe hasn’t been announced, but, since models in Europe are priced higher than their US counterparts, you can expect these new generation diesel hybrids to command a premium.  Mercedes has historically saved hybrid drivetrains for their top-end models, which may be the case here as well. Predictably there is no news about bringing these to the US.