Measurement of Emission Particulate Concentration in Direct Injection Gasoline Engines and Visualization Observation in the Cylinder

Abstract

In this study, a new engine measurement system was developed to investigate the formation and emission processes of particulate matter in the DI gasoline engine. The developed engine has an optically accessible sapphire window to visualize the combustion process, in addition to particulate emission measurement. Using the developed system, the effect of injection timing on particulate emission was investigated. As a result, it is found that the fuel film is formed due to the fuel impingement on the piston top surface with the excessively early or late injection timing. At the conditions, the luminous flame can be observed during the combustion of the fuel film attached on the wall and the exhaust particulate number concentration is increased.