Review of optical diagnostic technique for diesel spray

—To enhance the fuel efficiency and reduce both NOX and soot emissions in diesel engine, it is essential to
understand the mixture formation and the combustion process in the cylinder. The injection parameters such as pressure, mass and multiple approaches as well as the impingement play an important role in mixture formation, combustion process and emissions. Previous works have addressed various optical diagnostic techniques. This review describes those factors mentioned above systematically to clarify the diesel spray in the compression ignition engine. Therefore, a diesel vehicle with better fuel economy and low emission that meets thestringent regulation across the world could be realized.