TY - JOUR TI - Numerical analyses of a hydraulic hybrid powertrain system for a transit bus AU - Kitanović Marko AU - Popović Slobodan J AU - Miljić Nenad L AU - Mrđa Predrag D JN - Thermal Science PY - 2020 VL - 24 IS - 1 SP - 159 EP - 170 PT - Article AB - A dynamic programming optimization algorithm has been applied on a transit bus model in MATLAB in order to assess the fuel economy improvement potential by implementing a hydraulic hybrid powertrain system. The numerical model parameters have been calibrated using experimental data obtained on a Belgrade’s public transport bus. This experiment also provided the representative driving cycle on which to conduct simulation analyses. Various functional parameters of a hydraulic hybrid system have been evaluated for obtaining the best possible fuel economy. Dynamic programming optimization runs have been completed for various hydraulic accumulator sizes, preload values and accumulator foam quantities. It has been shown that a fuel economy improvement of 28% can be achieved by implementing such a system. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR35042: Research and Development of Alternative Fuel and Drive Systems for Urban Buses and Refuse Vehicles with Regard to the Improvements of Energy Efficiency and Environmental Characteristics]