This research focused on the effects of split injection on combustion in a diesel environment. It was done in a specially designed engine-fed combustion chamber (swirl ratio of 5) with full field optical access through a quartz window. The simulated engine combustion chamber used a special backwards spraying injector (105°).The electronically controlled injector could control the size and position of it's, two injections. Both injections were through the same nozzle and it produced very rapid injections (1.5 ms) with a maximum injection pressure of 130 MPa.Experimental data included: rate of injection, injector pressure, combustion chamber dumping (NO & NOx concentrations), flame temperature, KL factor (soot concentration) combustion pressure, and rate of pressure rise.Injection rates indicate that the UCORS injection system creates very rapid injections with the ability to produce controllable split injections. From combustion pressure data, a split injection can be injected earlier in the combustion cycle while creating a similar pressure history to a single injection.These experiments indicate that a split injection initially produces less soot but a single injection oxidizes its soot rapidly to similar levels. A split injection reduces NO and NOx by 50 - 60 % when compared to a single injection while limiting the peak rate of pressure rise to 75% of a single injection.