Model based engineering and realization of the KAYOOLA Electric City Bus powertrain

In the race to decrease the well-to-wheels fuel consumption and improve environmental stewardship, automakers and researchers worldwide have moved to electrify the vehicle powertrain for personal and public transportation. The Center for Research in Transportation Technologies at Makerere University is exploring electric vehicle transportation technology as a plausible solution to traffic issues in Uganda´s urban centers and cities. Electric vehicle transportation in Africa´s cities is a practical solution due to the fact that most of these cities are on a relatively small area; distances involved are small. This paper presents the technical, operational and functional aspects that were considered in the design of the KAYOOLA Electric City Bus, which has a drive cycle that suits the public transport system in Kampala City in Uganda. Since Battery Electric Vehicles have specific on-board energy, the powertrain for the KAYOOLA electric city bus was designed following the specific road-load requirements of typical city drive cycle from data obtained from actual road measurements in Kampala city. For range extension, Onboard solar charging is incorporated. To accurately predict performance, Autonomie-Modeling and simulation tool kit for light and heavy duty vehicles developed by Argonne National Laboratory was used to model and simulate the entire powertrain, noting effects of the grades, range, speed and drive cycles on the battery SOC and voltage. Design iterations are made to meet performance targets. This approach was employed to reduce time between concept development and prototyping while maximizing efficiency. The results shall inform the integration of key powertrain technologies into the KAYOOLA Electric City Bus.