Combined Sizing and EMS Optimization of Fuel-Cell Hybrid Powertrains for Commercial Vehicles 2019-01-0387
During the last years, fuel-cell-based powertrains have been attracting a lot of attention from vehicle manufacturers for reducing vehicle-related Greenhouse Gas (GHG) emissions. Amongst the different fuel-cell types, Proton Exchange Membrane Fuel-Cells (PEMFC) have the greatest potential for utilization in automotive applications, due to their relatively high technical readiness, market availability and utilization of hydrogen (H2) fuel. In addition, Solid Oxide Fuel-Cells (SOFC) show good potential due to existing re-fueling infrastructure for light hydrocarbons (e.g. diesel). This study focuses on the application of both PEMFCs and SOFCs in Fuel-Cell Hybrid Electric Vehicle (FCHEV) architectures for commercial vehicles. Delivery vans in the 2.5t-3.5t weight range, coach buses and tractor-type long-haul trucks are considered energy-driven types and highly suitable for fuel-cell systems, which have high energy densities but low power densities. Due to the complexity of such hybrid architectures, powertrain design loops can be time-consuming. This study proposes a combined component sizing process with Energy Management (EMS) optimization for determining powertrain performance and total system costs. In the suggested approach, the initially considered design space is reduced to a lower number of feasible power source combinations based on initial estimations, fixed component efficiencies and vehicle performance requirements. An optimization algorithm is then utilized for all the feasible combinations on different drive-cycles, i.e. the time-based WLTP drive-cycle for delivery vans and modified distance-based VECTO drive-cycles for coach buses and long haul trucks, with more detailed component performance characteristics. The suggested design approach for FCHEV powertrain architectures is analyzed and presented.
Tommi Jokela, Athanasios Iraklis, Bill Kim, Bo Gao