Conversion of a Small Size Passenger Car to Hydrogen Fueling: Focus on Vehicle Dynamics and ECU Remapping Requirements 2023-24-0065

Converting spark ignition (SI) engines to H₂ fueling is an attractive route for achieving zero carbon transportation and solving the legacy fleet problem in a future scenario in which electric powertrains will dominate. The current paper looks at a small size passenger car in terms of vehicle dynamics and electronic control unit (ECU) remapping requirements, in the hypothesis of using H₂ as a gasoline replacement. One major issue with the use of H₂ in port fuel injection (PFI) engines is that it causes reduced volumetric efficiency and thus low power. The vehicle considered for the study features turbocharging and therefore complete or partial recuperation of lost power is possible. Other specific requirements such as injection phasing were also under scrutiny, especially as PFI was hypothesized to maximize cost effectiveness. A 0D/1D model was used for simulating engine running characteristics as well as vehicle dynamics. One of the main conclusions is that at low rpm there should be only a minor influence on vehicle dynamics, while at the higher end completely comparable performance is achievable. In terms of acceleration, the small passenger car considered for the study loses around 10% performance between 0-100 km/h, but it is possible to have same dynamic response when accelerating from 70-120 km/h. After optimizing the gear shift strategy, the energy consumption between gasoline and H₂ version are the same, with zero tailpipe CO₂ emissions for the hydrogen.