A Study about Imaging Post Processing in Flame Front Detection in an Optical Research Engine Operating with Anhydrous Ethanol

Resumo

Copyright © 2017 SAE International.In the last few decades a significant effort has been stablished in the automotive industry as well as in academic community towards increasing the renewable fuels applications in internal combustion engines, such as alcohol and gas derived sources. Meanwhile, turbo charging direct-injection spark-ignition engines have become fundamental features to achieve downsizing purposes, increasing power generation efficiency and attending high restrictive emissions regulations that have being taking place recently. For this study, experimental tests were carried out in a single cylinder research engine considering direct injection (DI) and port fuel injection (PFI) operations with anhydrous ethanol. The aim of this paper is to present a review and conduct further investigation about methodologies applied for imaging post processing considering chemiluminescence technique applied in an optical research engine. Crank angle resolved OH∗ and CH∗ flame chemiluminescence images were acquired in cycle based temporal evolution for consecutive engine cycles. Distinct intensification setups were adjusted based on an intensifier usage to evaluate its influence on radicals' evolution and on flame front determination. Forthwith image acquisition, a post processing routine was conducted in order to determine flame radius, and speed through distinct image segmentation and algorithms techniques. Finally, former researches are referenced and compared to current results in order to better correlate the study conducted. The contribution of current research work within the state-of-the-art in optical engines researches remains in the adoption of different cameras set up and post-processing methods for the characterization of flame behavior in an optical spark ignition (SI) engine fueled with anhydrous ethanol.