Toyota Mirai: Powertrain Model and Assessment of the Energy Management

Toyota Mirai is a widely known fuel cell hybrid vehicle and its powertrain represents a benchmark for engineers and researchers. This work presents a lumped-parameter low-order model of Toyota Mirai powertrain and an assessment of the energy management focused on fuel economy and battery and fuel cell degradation. In addition, a rule-based strategy is proposed to reproduce the behavior of Toyota Mirai energy management strategy. The powertrain model and the proposed strategy are validated against experimental data. The assessment of the energy management is performed by comparing the Toyota Mirai strategy with optimal strategies obtained offline via dynamic programming. Different optimal strategies are computed by including the demand of the fuel cell and the battery in the cost function. Simulation results show a high correlation between the proposed model and strategy compared to the experimental data. Comparison of Toyota Mirai strategy with the optimal strategies reveals a small margin for improvement in fuel economy and higher margins in terms of demand of the fuel cell and battery.