Experimental and Numerical Investigation of a Passive Pre-Chamber Jet Ignition Single-Cylinder Engine

In the framework of an increasing demand for a more sustainable mobility, where the fuel consumption reduction is a key driver for the development of innovative internal combustion engines, Turbulent Jet Ignition (TJI) represents one of the most promising solutions to improve the thermal efficiency. However, details concerning turbulent jet assisted combustion are still to be fully captured, and therefore the design and the calibration of efficient TJI systems require the support of reliable simulation tools that can provide additional information not accessible through experiments. To this aim, an experimental investigation combined with a 3D-CFD study was performed to analyze the TJI combustion characteristics in a single-cylinder spark-ignition (SI) engine. Firstly, the model was validated against experiments considering stoichiometric mixture at 3000 rpm, wide open throttle operating conditions. Then, after the robustness of the proposed approach was assessed, a sensitivity analysis on the relative air-to-fuel ratio (i.e., 1.4) was investigated in order to highlight and to compare the propagation of the flame/reactive products jets from the pre-chamber to the main chamber.