Piston configuration for reducing smoke and particulate emissions from direct injected engines

Abstract

A diesel cycle, direct injected internal combustion engine is provided with a piston recess or bowl into which fuel is injected each combustion cycle. One or more reaction chambers adjacent the piston recess are in communication with the recess through an array of discrete orifices located along the side wall of the recess. Partial reaction of fuel and air in the reaction chambers each combustion cycle produces radicals including intermediate species for seeding a fuel air mixture of a following combustion cycle through a delayed discharge of radicals from the reaction chamber into the piston recess. The discrete orifices are arranged in a specific array that ensures a desired chaotic flow in the reaction chambers and maximum interaction between radicals discharged from the reaction chamber and the soot cloud formed in the combustion chamber upon ignition of the fuel air mixture in the piston recess. Two or more rows of orifices may be used with at least one row located centrally along the reaction chamber cross-section and at least a second row intersecting the first row and arranged diagonally or vertically relative to the first row. The diagonal or vertical row includes orifices that intersect the reaction chamber tangentially at upper and lower regions thereof. The disclosed apparatus results in an exhaust effluent having markedly reduced smoke and particulate components.