48 V P2 Hybrid Vehicle with an Optimized Engine Concept - Optimum Drivability with Excellent Fuel Economy and Cost-Efficiency

摘要

The vehicle concept presented in this paper is aimed at the market between the 48 V starter generator systems and high-voltage hybrid systems. The 48 V hybrid system presented here, which offers a highly attractive cost-benefit ratio, enjoys a special significance as one of the few P2 hybrid vehicles incorporating a manual transmission. To ensure both significant CO_2 savings and excellent drivability, a high-compression turbocharged gasoline DI engine was combined with "late intake valve closing" and a RaAx turbocharger. This engine concept was used as a basis for creating a highly efficient overall powertrain with a 48 V P2 hybrid system. The concept incorporates synergies that can be leveraged through the combination of an optimized combustion engine and 48 V technology. An electrically heated catalyst enables innovative operating modes in compliance with the emission legislation. The central component of the hybrid system is a P2 hybrid module, which enables greater recuperation potential than a P0 belt starter system, as well as all-electric driving maneuvers and, in turn, a CO_2-optimized operation strategy. It is characterized in particular by an electric motor that is positioned parallel to the transmission input shaft. The emachine is connected to the driveline via a belt drive that includes as well a variable piston- A/C compressor with a magnetic clutch. In addition to a "K0" clutch for disengaging the combustion engine the hybrid module includes the also integrated automatic "K1" drive clutch. Among the features of this P2 hybrid architecture is the option of electric vehicle air conditioning at zero oncost and all-electric low speed driving mode. The latter lays the foundation for automated parking, even for manual transmission vehicles. The ability to start the engine quickly and smoothly via the 48 V electric motor - comparable with a starter generator system - is also still available. The restart refinement is prerequisite for a CO_2-optimized overall drive strategy, which combines the optimum drive methods of the overall powertrain while simultaneously ensuring a refined driving experience. The hybrid module can be universally combined with manual and automatic transmissions of any type.