Mercedes-Benz is preparing to phase out its current range of V6 engines to return to inline six-cylinder powertrains. Reports have now emerged of a "mild hybrid" system to also feature as part of the straight-six engine range.
The latest information (though yet to be confirmed) comes out of the USA, courtesy of Car & Driver, claiming that the all-new modular engine will arrive with a 48-volt mild hybrid system as standard.
The term “mild hybrid” indicates that the six-cylinder petrol engine will be be accompanied by a combined starter-alternator unit, mounted to the crankshaft.
Although not strong enough to drive the vehicle by itself (as can a "full-hybrid"), a mild-hybrid unit provides assistance to the petrol engine when under load or allow it to shut down when coasting, braking or when stopped. It provides an estimated 13-15kW of extra power.
It’s also much stronger than a normal starter motor, meaning that the engine can be re-started from idle-stop rest much more quickly than a traditional system. The unit can also operate as a generator, harvesting up to 15kW of power under regenerative braking.
While the hybrid capabilities of the system are modest, the new 48v system aims to reduce fuel consumption by between 10 and 15 percent in normal driving conditions.
The petrol engine meanwhile will reportedly wear the M256 designation, and be based on the same modular architecture as the new OM654 diesel engine that will debut in the new E 220 d variant of the all-new E-Class range, set to debut in Australia soon.
Power targets for the M256 are yet to be announced, but, like the V6 engine it replaces, the new straight-six engine will likely be available in a number of outputs depending on the application. Turbocharging can also be expected to be an integral part of the new engine range.
The updated S-Class range, set to be unveiled later this year will be the first vehicle to house the new engine.
Mercedes-Benz however is understood to have a rapid roll-out planned for the new powerplant which will eventually make its way across the entire longitudinally-engined Mercedes range.
All petrol straight-six cars will feature the mild hybrid system, which will take the place of Benz’s existing non plug-in hybrid range. A new diesel inline six, based on the same component set is also set to follow, replacing the current diesel V6.