Numerical and Experimental Study of Passive Pre-chamber Turbulent Jet Ignition on Wankel Engine

This study aims to increase the flame speed in the Wankel engine by using turbulent jet ignition. The Wankel engine suffers from poor exhaust emissions and high fuel consumption due to insufficient combustion speed and the inability to spread the flame throughout the shallow structured combustion chamber. With the hot turbulent flame jets obtained through the orifices, the turbulence level of the combustion chamber and the flame speed can be increased, as a result, the fuel consumption can be reduced. Various pre-chamber geometries were simulated with the Converge Studio program to determine the geometry features that can give better results. Taguchi method and ANOVA (Analysis of variance) tests were conducted to optimize the parameters and levels. Afterward, passive pre-chamber tests were conducted on a single-rotor Wankel test engine in the Istanbul Technical University Automotive Laboratory. Several load and speed operating conditions were tested, and results were compared with the base engine that has the classical spark ignition system. During the experiments, the parameters were kept constant to see the direct effect of the pre-chamber on the combustion rate. The preliminary results show that classical spark ignition engine has better specific fuel consumption and HC emissions in general. However, the turbulent jet ignition system with a passive pre-chamber has the potential to improve the Wankel engine performance at certain operating conditions.