Three-dimensional measurements of the in-cylinder diesel flame development under low crank speeds based on computed tomography

Understanding the dynamics of the combustion process in the combustion chamber is critical to improve the performance of the engine. The computed tomography technology makes it possible to reconstruct the three-dimensional distributions of flame chemiluminescence signals which can be used to analyse flame development processes inside the combustion chamber. In this study, the flame intensity distribution and evolution inside an optical engine are reconstructed under multiple low crank speeds, by utilizing cross-interface computed tomography. The reconstructed flames provide 3D information on flame volume and intensity evolution, which presents superiority on clarifying the effects of crank speeds on flame development. Meanwhile, flame development along the piston movement direction is analysed based on the 3D results. The study reveals the 3D structure of the in-cylinder flame and makes it possible for further investigation of the 3D information of the in-cylinder combustion process in the future.