Electrification of heavy-duty trucks has received significant attention in the past year with states such as California requiring a percentage of tractor trailers, delivery trucks and vans sold to be near-zero emissions by 2035. However, the relatively lower energy density of batteries in comparison to diesel fuel as well as the operating profiles of heavy-duty trucks makes the application of electrified powertrain challenging. As the heavy-duty industry deals with solving challenges around application of electrified powertrain with respect to operating profile, payback period, cost, range and charging infrastructure, there are two alternative paths that appear to be viable to meet future regulatory demands. As a near-term solution for the 2024-2030 timeframe, hybridization of the conventional diesel powertrain seems to be the most attractive approach for meeting greenhouse gas standards with an acceptable payback period. For the longer-term, 2030 and beyond, wherein low CO2 or near-zero emission vehicles need to be considered, the pathway towards range extenders, battery electric and fuel cell vehicles will gain prominence.To investigate the potential of these alternate powertrain concepts to meet future fuel economy and emission standards, FEV has developed a model-based design approach for system level sizing and optimization of electrified powertrain components. In this study the approach has been applied for a Class 6-7 vocational truck, which typically experiences low speed driving with frequent start-stops. A dynamic model for the baseline diesel vehicle was developed and calibrated to test data including fuel efficiency and engine-out NOx emissions. The baseline diesel vehicle was then updated with hybrid powertrain components to evaluate parallel hybrid (P1, P2, P3, P4), all-electric, diesel range extender, gasoline range extender, Compressed Natural Gas (CNG) range extender, and fuel cell range extender configurations. The powertrain components for each configuration were optimized using a Design of Experiments (DOE) approach that applies the Gaussian Process (GP) modeling technique. The study analyzed several key parameters for architecture selection including cost of ownership, fuel efficiency, emissions, payback period, lost payload opportunity, range, and battery life. Overall, the analysis showed that for a near-term less-disruptive scenario wherein the conventional diesel powertrain layout is preserved, a 48V P3 parallel hybrid architecture is the most cost-effective solution. While for a near-term more-disruptive scenario, the Internal Combustion Engine (ICE) based Range Extender Electric Vehicle (REEV) shows the highest potential to reduce greenhouse gas emissions while achieving lower cost of ownership than the baseline diesel vehicle. For a longer-term more-disruptive scenario, the all-electric vehicle configuration can achieve parity with the baseline vehicle cost of ownership provided the vehicle driving range requirement is limited to 100-150 miles. The analysis further highlights that the overall benefit of an all-electric powertrain solution is significantly dependent upon the advancements in battery technology and the vehicle range requirements.

System Level Modeling Approach for Evaluation of Hybrid, Electric and Fuel Cell Powertrain Solutions in Medium Heavy-Duty Vehicles

Paper Proceedings: https://asmedigitalcollection.asme.org/ICEF/ICEF2021/volume/85512

ASME 2021 Internal Combustion Engine Division Fall Technical Conference (ICEF2021)

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.