Effect of Starting Idling Condition and Mixture Concentration of a Turbocharged GDI Engine on Particle Emission
This is an experimental research on the distribution of particulate emissions in the exhaust gas of a turbo-charged gasoline direct injection(GDI) engine by using a fast particle spectrometer (DMS500). The results showed high particulate emissions within a few seconds after startup. As the machine continued to warm up, the accumulation mode particulate emissions reduced. In hot idling condition, nucleation mode particulates were the dominant exhaust particulates . With the excess air ratio reduced, the peak cylinder pressure increased, the combustion duration short-ened, the average temperature inside the cylinder gradually increased, post-combustion cylinder temperature decreased and the oxygen content in the mixture lowered, which were conducive to soot formation and elevated cyclic variations when using lean gas. At low load, the accumulation mode particulates were sensitive to the change of the excess air ratio. After we increased load and speed, concentrations of accumulation mode particles decreased, which was demon-strated by the decreasing excess air ratio and increasing concentrations of accumulation mode particles. When using concentrated mixture, exhaust particulate mass rapidly increased. In the experimental conditions, the geometric mean diameter (GMD) and count median diameter (CMD) of exhaust gas particles were basically less than 10 nm. When the excess air ratio is 0.8, the values of GMD and CMD particulates were comparatively large.
gasoline direct injection enginecylinder pressureheat release rateparticulate
NETL
NSTL
万方数据
维普
