Design, Implementation, and Evaluation of an Innovative Vehicle-Powertrain Eco-Operation System for Plug-In Hybrid Electric Buses

Transit buses serve a vital role in sustainable transportation systems, providing mobility to millions of passengers daily. These buses primarily operate on fixed routes in urban areas, leading to frequent stops at bus stops and traffic signals, which contribute to them having low fuel economy. In recent years, hybrid electric buses and plug-in hybrid electric buses (PHEBs) have gained significant interest in transit applications. However, the energy efficiency of early HEBs and PHEBs is limited as they rely primarily on simple charge sustaining strategies. This paper presents the design, implementation, and validation of a Connected Eco-Bus system that utilizes connected and automated vehicle technology to improve the energy efficiency of a power-split PHEB. The system co-optimizes the PHEB's vehicle dynamics and powertrain controls by leveraging connectivity and partial automation (Level 1) capability. A case study is conducted with the Connected Eco-Bus system operating on a typical urban route where its performance is evaluated through both microscopic simulation and Dynamometer-in-the-Loop testing. The results demonstrate that the Connected Eco-Bus system can achieve energy efficiency improvements of up to 32.4%, which would thereby contribute to a more sustainable transportation system.