Energy balance and hydrogen exhaust emissions of the second-generation Toyota Mirai
Breno Mendes Alves, Pierre Savignac, Pierre Leduc
Abstract
Fuel Cell Electric Vehicles (FCEVs) stand as a promising alternative to conventional Internal Combustion Engine Vehicles (ICEVs), offering lower greenhouse gas emissions and more efficient onboard energy utilization, while presenting an extended range in comparison to Battery Electric Vehicles (BEVs). This paper delves into the performance evaluation of the Toyota Mirai II FCEV, a leading model in the market. It emphasizes key performance metrics such as energy consumption, power balance, and tailpipe emissions on controlled test-bench experiments, including its response to varying driving conditions and energy demands. Many variables of the powertrain were assessed, including electrical measurements, as well as measurements of the cooling loops and of the exhaust gases. The energy transformation processes happening within this architecture can then be analyzed, detailing the performances of the fuel cell system. Fuel cell stack LHV efficiency peaked at low power demands at around 70 %, which dropped to 54 % near maximum output stack power at around 130 kWe. These values drop to 62 % and 46 %, respectively, when considering efficiency at the fuel cell system level. Hydrogen consumption on a WLTC driving cycle was accounted at 0.8 kg H2 /100 km. At steady-state power demands, hydrogen purges were measured between 0.8 % and 2.4 % of the total amount of fuel used. This study enriches the ongoing dialogue surrounding sustainable transportation solutions by conducting a data-driven analysis of the Toyota Mirai II .