Flame Propagation Analysis of Anhydrous and Hydrous Ethanol in an Optical Spark Ignition Engine

The present study aims to evaluate the intrinsic differences in in-cylinder combustion in low load and low-speed conditions by applying experimental and numerical techniques. The experimental apparatus consisted of an AVL5406 SI-PFI single-cylinder with optical access operating under two different fuel delivery methods: Port Fuel Injection (PFI) and Direct fuel Injection (DI) with anhydrous ethanol (E100) and hydrous ethanol (E96W4). The outcomes of the engine-like conditions tests were evaluated based on the quantitative analysis of the flame propagation and on the thermodynamic data obtained using INDICOM. A Video Scope VS4-1845HS high-speed camera providing cycle resolved UV-visible digital image captured the natural emission of the flame for each test. Forthwith image acquisition, the flame propagation characteristics were post-processed through image segmentation techniques. Finally, relevant literature was revised to support the results and findings obtained at this time. The contribution of this study to the internal combustion engines research remains in gathering more information about in-cylinder flame front propagation and combustion stability for E96W4 and E100 ethanol under partial load and stoichiometric and lean conditions.