Detailed Investigation of Multiple Injections in DI Diesel Engines

Diesel injection is known to influence the combustion efficiency and the production of particulate and NOx emissions. Recent developments in the fuel injection including split injection wherein the fuel is injected in two or three pulses rather than with a single injection have led to significant improvements in terms of the reduction in the emissions. To date, the experimentation on these methods has focused primarily on varying the rise time, duration, and dwell between the injections while observing the outcome in terms of chamber pressure, heat release, and emissions. It is the purpose of this work to investigate the details of the atomization, fuel penetration and mixing under the split injection strategies. Laser light sheet imaging with image processing will be used to study the global features of the transient spray events. The PDPA will then be used to probe the details of the spray obtaining time-resolved drop size and velocity data at representative points within the pray plume. Conditions that mimic those used by Reitz at the U. of Wisconsin to obtain improved performance will be studied in the Phase I project. These data will be acquired in a pressure chamber operated at type diesel cylinder pressures.