Air-path control of a heavy-duty hydrogen internal combustion engine

Abstract

Hydrogen internal combustion engines (H2-ICEs) offer a promising zero-carbon option to conventional diesel engines in the heavy-duty industry. This technology presents challenges in air-fuel ratio (AFR) control due to the wide flammability range and fast combustion characteristics of hydrogen. Maintaining the relative AFR (λ) value within acceptable limits is critical to reducing NOx emissions while ensuring stable engine operation. This thesis studies the feasibility of implementing an air-path λ-control strategy to improve AFR regulation in the engine. A grey-box modeling approach was employed to map system parameters for the gas transport dynamics, utilizing engine test cell data collected under various operating conditions. The estimated parameters were then used to design and tune a feedback controller with dead time compensation. The control strategy was tested in a simulation environment, demonstrating improved λ tracking with minimal impact on the engine performance compared to a baseline strategy. The results demonstrate that air-path lambda control is a promising approach for managing the air-fuel ratio in H2-ICEs, with potential for further improvements under extended operating conditions.