Part 2 of the five-part series on the electrification of mobility at Mercedes-Benz
The 48-volt electrical system: the way to the “mild” hybrid at Mercedes-Benz
In addition to the first particulate filter for gasoline engines (from 2017), there are further developments on the road map for the “classic drives” at Mercedes-Benz. Because even with all the euphoria about the future, the combustion engine and the diesel are still alive. It is still these engines that move us every day. There are still no alternatives for some application purposes and customer requests and as long as this is the case, the further development of these units is on the agenda.
This can be the 48-Volt electrical system
Raising the on-board voltage from 12 to 48 volts means lowering the currents that flow to obtain the same power. This can be used to reduce the cross-section of lines, for example, which in turn leads to fuel savings through less weight. But - that's not the biggest advantage of the system.
Recuperation, boost and start & stop with 48 volts
The fourfold voltage enables efficient start-stop systems, which in the case of the six-cylinder in-line engines and in connection with an automatic transmission at Mercedes-Benz will lead to the use of an integrated starter-generator. This electric motor works in a similar way to the electric motor of the plug-in hybrid variants, but without the need for the high-voltage system, as its power consumption is limited. The integrated or belt-driven starter generator is also a very durable solution for start-stop systems.
Integrated starter generator
An integrated starter generator can have a supportive effect both when accelerating and when recuperation is more efficient. In combination with the 48-volt on-board network and a 48-volt battery, efficiency and driving comfort increase. An integrated starter generator also serves as a starter and yet acts much more sensitively than this. Start-stop systems will then no longer be perceived as troublemakers, but will be praised for the increase in efficiency while maintaining comfort. The integrated starter generator will only be considered for high-priced variants. For the vehicles in the smaller classes - for example the A-Class with a four-cylinder engine - the belt-driven starter generator is in the planning.
Belt-driven starter generator
The cheaper solution is a replacement for today's alternator. Also acts as a “dynamo” as well as an electric motor. The use of 48-volt technology makes this system more efficient than it was previously possible to implement. The installation instead of a classic alternator, which does not contribute to the start-stop system and does not have a boost function, is not much more complex. Converting existing systems to a 48-volt RSG is therefore a manageable task on the cost side.
48 volts will also electrify the “classics”
Everyone understood that there is no getting around e-mobility. And even if we will live and drive with bridge technologies (PHEV) or classic drives for a certain time - the leap in development towards the 48-volt electrical system will at least lead to the electrification of classic drive systems. Elsewhere, such hybrids were called “mild hybrids” - at Mercedes-Benz one speaks of the electrification of the drive train. Both are right .. and that's a good thing!
Read even more about E-strategy at Mercedes-Benz:[divider] [/ divider]
- Part 1 - The fuel cell SUV
- Part 2 - The 48-volt technology for classic drives (from June 17.6)
- Part 3 - The electric car platform from Mercedes-Benz (from June 24.6th)
- Part 4 - B2B e-mobility in the city (from 1.7.)
- Part 5- The new smart Electric Drive (from 8.7.)