Development of 48V powertrain systems at Mercedes-Benz

Abstract

Technical solutions to conventionally reduce the fuel consumption and CO2 emissions of combustion engines have been largely exhausted. In order to cope with continually increasing requirements via legislation and customers’ expectations, more costly and technically complex solutions must be investigated and introduced to meet these requirements. These technical and legislative challenges are also constrained by providing the customer the high level of performance and comfort they are accustomed to in a premium segment vehicle from Mercedes-Benz, while keeping the additional costs for the customers to a minimum. The 48V electrification of the powertrain and a number of auxiliaries has a great deal of potential to achieve these goals. Introducing a 48V system can be a cost-efficient, entry-level hybridization offering a large amount of the functionality of high voltage hybrids at a fraction of the cost. This makes it an attractive step in lowering the overall fleet consumption of a vehicle manufacturer for customers who are not interested in a plug-in hybrid or an electric vehicle at this time.

In additional to fuel consumption improvements, the increase of the voltage level allows for additional electric power which can be used to electrify auxiliaries which are currently mechanically powered. Furthermore, the additional electrical power can be used to satisfy the ever increasing power requirements for comfort, infotainment and safety or autonomous driving systems.

There are numerous topologies for the hybridization of a powertrain with a 48V system, two systems introduced at Mercedes-Benz with the newest motors will be discussed in detail and their functionality will be compared. Following this, further applications will be evaluated and the future compatibility of 48V systems will be characterized.