A Fast and Reliable CFD Approach to Design Hydrogen SI Engines for Industrial Applications

SI engines fueled with hydrogen represent a promising powertrain solution to meet the ambitious target of carbon-free emissions at the tailpipe. Therefore, fast and reliable numerical tools can significantly support the automotive industry in the optimization of such technology. In this work, a 1D-3D methodology is presented to simulate in detail the combustion process with minimal computational effort. First, a 1D analysis of the complete engine cycle is carried out on the user-defined powertrain configuration. The purpose is to achieve reliable boundary conditions for the combustion chamber, based on realistic engine parameters. Then, a 3D simulation of the power-cycle is performed to mimic the combustion process. The flow velocity and turbulence distributions are initialized without the need of simulating the gas exchange process, according to a validated technique. However, coupled 1D-3D simulations of the engine scavenging can be carried out as well to increase the accuracy of the predicted intake valve closing (IVC) flow fields. The proposed methodology was validated against experimental measurements from a pent-roof single-cylinder spark-ignition (SI) engine, in which different values of hydrogen-air dilution were investigated. The achieved results were able to capture the measured pressure and heat release trends, demonstrating the industrial applicability of the presented methodology.