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Title: Simulations of the Fuel Economy and Emissions of Hybrid Transit Buses over Planned Local Routes

We present simulated fuel economy and emissions city transit buses powered by conventional diesel engines and diesel-hybrid electric powertrains of varying size. Six representative city drive cycles were included in the study. In addition, we included previously published aftertreatment device models for control of CO, HC, NOx, and particulate matter (PM) emissions. Our results reveal that bus hybridization can significantly enhance fuel economy by reducing engine idling time, reducing demands for accessory loads, exploiting regenerative braking, and shifting engine operation to speeds and loads with higher fuel efficiency. Increased hybridization also tends to monotonically reduce engine-out emissions, but trends in the tailpipe (post-aftertreatment) emissions involve more complex interactions that significantly depend on motor size and drive cycle details.
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  1. ORNL
Publication Date:
OSTI Identifier:
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: SAE International Journal of Commercial Vehicles; Journal Volume: 7; Journal Issue: 1
Research Org:
Oak Ridge National Laboratory (ORNL)
Sponsoring Org:
EE USDOE - Office of Energy Efficiency and Renewable Energy (EE)
Country of Publication:
United States