An obstruction is employed in a combustion chamber of an internal combustion engine. The obstruction is located within the chamber to generate turbulence and break-up or disrupt the soot rich zone within a directly injected quantity of fuel that is burning. More specifically, a ring disrupts fuel jets directly injected into the combustion chamber that impact on or are influence by the ring. The ring can be suspended from the piston or from the fire deck. Post-type obstructions help generate turbulence and are also targeted at disrupting the soot rich zone of the burning fuel jets. A method involves disrupting the soot rich zone or reducing soot generated within the combustion chamber and increasing burn rate by impacting the fuel jets on an obstruction within the chamber.