The smoke emission reduction is most significant with the emulsion as seen in Fig. 10. There is a little change in the smoke level between the pure diesel and water injection methods. This
could be due to the absence of the micro-explosion phenomenon even though there is an additional benefit from increase in OH concentration and premixed combustion phase by long ignition delay.
Thus the micro-explosion phenomenon may play a major role to control smoke level with water-in-oil emulsion.