Energy Management of Hydrogen Hybrid Electric Vehicles -- A Potential Study

Abstract

The hydrogen combustion engine (H_2ICE) is known to be able to burn H_2 under ultra-lean conditions, while producing no CO_2 emissions and extremely low engine-out NO_x^eo emissions. Immediate goals, as for instance the upcoming EURO 7 NO_x limitations, can be reached more easily as extremely low engine-out NO_x^eo emissions facilitate the reduction of the overall tailpipe NO_x^tp emissions. In this work, the feasibility of achieving consistent reductions in NO_x^eo emissions through the implementation of electric hybridization of an H_2ICE-equipped passenger car (H_2-HEV), combined with a dedicated energy management strategy (EMS) is discussed. In particular, the mixed H_2-HEV architecture is investigated and compared to a series H_2-HEV, a parallel H_2-HEV, and a base H_2-vehicle, which is only equipped with an H_2ICE. For hybrid vehicles, a low H_2 consumption and low NO_x^eo emissions are conflicting objectives, the trade-off of which depends on the EMS and can be represented as a Pareto front. Overall, through the utilization of a dedicated energy management calibration, the mixed H_2-HEV demonstrates the capability to consistently achieve extremely low engine-out NO_x^eo emissions. For a broad range of driving missions, the mixed H_2-HEV is able to decrease the engine-out NO_x^eo emissions by more than 90%, while, at the same time, the H_2 consumption is decreased by over 16%, compared to a comparable non-hybridized H_2-vehicle. These significant emission reductions are possible without having to modify the exhaust-gas aftertreatment system, or the optimization of any of the individual drivetrain components, but solely by setting the EMS calibration accordingly.

Tasks

Reproductions