Dedicated Hybrid Powertrains for Passenger Car Applications: Evaluation of Gasoline Engine Concepts and Powertrain Topologies

Authors

Dipl.-Ing. M. Krüger, Dr.-Ing. J. Schwarzer, Dr.-Ing. E. Schünemann, Dipl.-Ing. J. Tophoven, Dipl.-Ing. J. Gömmel, Dr.-Ing. V. Neubert, Robert Bosch GmbH, Stuttgart:

Year

2023

Print Info

Production/Publication ÖVK

Summary

Hybrid powertrains can contribute significantly to the worldwide effort of further reducing CO2-emission in the passenger car segment. It must be assumed, that, in some regions of the world, future regulatory requirements can just be satisfied through the application of high-efficiency hybrid technologies, or their application might even be explicitly mandated. A good example are the development targets described in the China Technology Roadmap 2.0 [1]. Bosch is working on comprehensive solutions to satisfy these requirements, the so-called dedicated hybrid powertrains: through specific optimizations of the SI engine for its operation within an electrified powertrain and through matching of the electric powertrain with the transmission, efficiency potentials are exploited in the best possible manner. To identify target leading approaches, in this study, different Dedicated Hybrid Engine (DHE) concepts were systematically considered and, based on generic engine maps, compared in a D-segment vehicle using powertrain simulation. The efficiency assessment was done in combination with different market relevant hybrid-topologies. Here, the comparison between a P2-hybridisation and DHT-concepts was of particular interest (Dedicated Hybrid Transmission: serial-parallel, serial). To validate the theoretical potential of the single DHE technology bricks, they then were step-by-step integrated into a concept engine and evaluated on the engine test bench. Engine test results and powertrain simulation confirm that the full potential of hybridization can only be realized through holistically optimized hybrid-powertrains with DHE and DHT. Application of these powertrains, e.g. in the very relevant D-vehicle segment, will enable meeting future requirements, as proposed e.g. by the China Technology Roadmap 2.0.

ISBN

978-3-9504969-2-5