Contour plots of NO emission as a function of water emulsification
ratio and intake oxygen concentration under 57% and 100%
loads are shown in Fig. 5 respectively. Dashed linewas marked asNO
emission of the baseline, and the area of combination of water
emulsification ratio and intake oxygen concentration was divided
into two parts. In the diagram of the top left area, NO emission was
lower when compared to that of the original engine, indicating that
the NO emission of water emulsified diesel combined with intake
oxygen concentration in this area can be reduced compare to that of
the original engine. However, the bottom right corner is opposite.
From comparison of Fig. 5a and b, it can be found that compared to
the condition of 180 Nm, low NO emission area was wider at the
condition of 100% fuel throttle. It is consistent with the abovementioned
phenomenon that more supply of fuel under high load
condition would lead to an increase in moisture content in combustion
chamber and a greater inhibitory effect on NO emission.
3.3. The effect of water emulsion ratio and oxygen-enriched on
BSFC
As shown in Fig. 6a, when engine fueled with pure diesel (0%
water), the BSFC curve of engine is relatively straight, it means that
the increase of intake oxygen concentration had little influence on
BSFC, and the BSFC of 22%e24% intake oxygen concentration is