Laser diagnostics for spray of spark ignition direct injection (SIDI) combustion system

The technologies for development of spark ignition direct injection (SIDI) engines still need further research in China. Advanced spray laser diagnostics, three dimensional computational fluid dynamics (3-D CFD) modeling and the combustion diagnostics based on optical engine play leading roles in the development of SIDI combustion systems. Among these technologies, advanced laser diagnostics is becoming increasingly important, because through laser diagnostics one can realize visualization and quantitative measurements of in-cylinder processes, which are essential for validation of CFD modeling and understanding the physical phenomena in the mixture formation and combustion processes. This paper summarizes and compares various technologies in spray laser diagnostics which are used to provide information for modern SIDI combustion system development. The review includes diagnostics for spray structures, flow fields, droplet sizes and fuel evaporation, which enables optimization and matching of the spray, air flow and the combustion chamber of an SIDI combustion system.