Emission Formation in CI Engines

Schematic of a diesel injection spray is shown in Fig 2.3 .  A fully developed diesel spray may be considered to consist of three distinct regions based on the variations in fuel-air equivalence ratio, across the cross section of the spray as seen radially outwards from the centreline of spray.

• A fuel rich core where fuel-air equivalence ratio is richer than the rich flammability limits i.e.,
• Flammable region  in which   lies within the rich and lean flammability limits, i.e.,
• A lean flame-out region (LFOR) where is lower than lean flammability limits and extends up to the spray boundary i.e.,