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The Future of Mild Hybrid Systems in the Transmission
ISSN: 0148-7191, e-ISSN: 2688-3627
Published January 10, 2017 by SAE International in United States
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An innovative mild hybrid transmission concept is presented and the opportunities described that arise from the addition of an e-machine to the transmission system and the introduction of a freewheel mechanism. Design studies and simulation have shown that hybridising elements of the transmission system can extend the efficiency gains of 12V engine-based mild hybrid systems, specifically in small passenger cars. In addition, combined with the freewheel mechanism, this concept adds desirable features and functionality that justify its cost. The paper will demonstrate how some of this functionality will enable hybridisation of a far broader range of vehicles, helping manufacturers to significantly reduce their fleet CO2 emissions. While the energy storage requirements over a standard drive cycle for such a system have been shown in simulation to be well within the capability of a 12V battery pack, the peak power limitations of a 12V machine, if not addressed correctly, can lead to issues around driving refinement and safety. As well as reviewing the impact on transmission design and control, the paper also examines how the electrical system can be designed to overcome these limitations.
CitationHoward, J. and Savage, M., "The Future of Mild Hybrid Systems in the Transmission," SAE Technical Paper 2017-26-0101, 2017, https://doi.org/10.4271/2017-26-0101.
- Navigant Research, “Stop-Start Vehicles: Onboard Energy Storage, Lead-Acid Batteries, Lithium Ion Batteries, and Ultra-capacitors: Global Market Analysis and Forecasts”- Published Q2 2015
- Coppin, O., “12+12V architectures for CO2 emissions reduction through inno vative components and functionalities” - 13th International CTI Symposium 2014, Germany - Valeo Powertrain Systems - France, Dr. Ing. Oliver Coppin
- “48 Volt Electrification: 3rd International Conference Automotive 48V Power Supply Systems 2015 - The next step to achieving 2020 emissions - Els Peter
- SAE International Surface Vehicle Recommended Practice, “Laboratory Measurement of the Composite Vibration Damping Properties of Material on a Supporting Steel Bar,” SAE Standard J1637, Rev. Aug. 2007.
- Reeve, J., “A study of compact architectures using multiple 48V e-drives to create a low cost 30-45kW full hybrid system” - 9th International CTI Symposium 2014, Germany