Investigating the effects of turbulence inducement on diesel engine combustion and emission characteristics

In the present work, the effects of inducing in-cylinder turbulence through bluff bodies or internal jets are experimentally investigated on a direct injection diesel engine. The bluff bodies are placed horizontally across the piston cavity in the form of rods or rods wound with thin wire in different arrangements. The jet turbulence is introduced by holes on the piston crown, allowing a tangential entry of the working fluid into the piston cavity along the direction of swirl. The changes in performance, emission and combustion characteristics of the engine, due to these arrangements, are analyzed In general, horizontal bluff bodies do not result in significant advantage in fuel economy and smoke levels, but some reduction in NOX concentration is observed. More importantly, it is observed that the internal jets introduced through the tangential holes showed improvement in the engine brake thermal efficiency and exhaust smoke level with a marginal increase in NOX concentration.