Feasibility analysis of a direct injection H2 internal combustion engine: Numerical assessment and proof-of-concept

The present study is a proof-of-concept investigation of a lean hydrogen internal combustion engine aiming to understand and address its critical thermo-fluid dynamics aspects, by means of a multi-fidelity computational fluid dynamics approach. Starting from an existing gasoline engine, the influence of the most relevant parameters and components on performance and efficiency is investigated using both one- and three-dimensional simulation tools, with the goal of defining a comprehensive strategy for adapting the engine design to the new requirements imposed by the hydrogen fuel. In particular, the following parameters affecting the retrofit effectiveness are analyzed and modified by the authors: turbocharging system, injection strategy, compression ratio, valves timing and intake ports design. Promising performance are achieved with the final configuration, revealing that substantial improvements can be obtained through a dedicated design: the BMEP is consistently above 17 bar with a peak brake efficiency higher than 40%.