Experimental Study on Smoke and NO_x Reduction by High-Turbulent Two-Stage Combustion in Diesel Engines : (Trials of Variety Types of Piston Configurations, EGR Combination, and Fumigation)

Abstract

The authors previously reported significant reductions of particulate emissions by generating strong turbulence during combustion process. Extending this, it was attempted to reduce NO_x, particulate, and fuel consumption simultaneously by two-stage combustion ; forming a fuel rich mixture at the initial combustion stage to prevent NO_x formation, and inducing strong turbulence in the combustion chamber at the later stage of combustion to oxidize the particulate. The purpose of this study is to examine the further potential and extent of the two-stage combustion for the emission control. The paper shows experimental results for variety trials of piston configurations, EGR-combinations, and fumigation technology together with the two-satge combustion system. The result was not successful for realizing apparent improvement in emission and fuel consumption over wide range of operating conditions, although simultaneous reduction in NO_x and smoke was possible at limited conditions with the two-stage combustion. The paper provides information for discussing points to be investigated in the next stage and options for future combustion control technology.