Modelling hydrogen combustion in a spark-ignition engine using the imperfectly stirred reactor model

This study presents a zero-dimensional (0D) imperfectly stirred reactor model for predicting combustion modes in hydrogen spark-ignited engines, including normal, knocking, fast flame, and detonation conditions. Sixteen test cases are evaluated using three chemical mechanisms, with four cases representing each combustion mode. The results show that the 0D model effectively distinguishes combustion modes, with the main challenge being the differentiation between fast flame and detonation, which can be resolved by comparing auto-ignition time and combustion duration. The Keromnes and Konnov mechanisms show similar results whereas the Burke mechanism predicts longer combustion durations. The sensitivity analysis on unburnt gas temperature stratification reveals that normal combustion occurs in a more thermally homogeneous field whereas for knocking conditions, the 0D model requires a larger temperature variation in the end-gas to be accurate. Overall, the 0D model provides promising results for determining the combustion mode in hydrogen-fuelled SI engines. • A low-order model is proposed for hydrogen engine combustion mode determination. • It is validated with 16 cases and 3 chemical mechanisms. • The model can distinguish normal, knocking, fast flame and detonation conditions. • Unburnt gas temperature stratifications of 50 K can be used for most conditions.