The tailored powertrain for 48 V – options for the gasoline engine – chance for future Diesel engines

The next steps of fuel consumption legislation will require a combination of engine measures with various electrification measures, dependent on the vehicle segment, to reduce the energy demand targets of the vehicle. The introduction of 48V electrical architecture provides increased electric recuperation and limited electric driving at lower cost compared to full hybrid solutions, offering considerable fuel reduction potential in the WLTC.Current belt starter-generator systems (P0) already realise direct recuperation and torque boost functions. Additionally they can support a highly effective electrical supercharging system. More flexible powertrain architectures with a clutch to disconnect the engine form the driveline (P2,P3,P4) allow pure electric driving in a limited range, or simplification of the base engine towards the goal of a beltless engine. Demand controlled, electrical auxiliaries are already in series production for the cooling-, vacuum- or air conditioning systems. Additional areas of interest are the oil system and variable elements in the valve train or crank train.The optimum balance of electrical and mechanical functions on the base engine and its periphery requires an application dependent evaluation with the aim of minimized overall system complexity and cost as well as added customer value.In previous papers [13, 14, 16] this had been evaluated for a gasoline engine application.In this paper, the electrical efficiency potential of the 48V E-Motor is compared in different architectures and dependent on the electrical power. Furthermore the effects of friction and power loss of electrified components are investigated in detail for the relevant driving conditions. The implementation of the accessary electrification has been investigated for a conventionally optimized gasoline and diesel engine in a Csegment vehicle with the aim of a tailored 48V base engine and focus on modular functional integration.