Effect of Gasoline Fuel Additives on Combustion and Engine Performance

SM
D
, µ
m
Pressure, bar
100% Dodecane
25% Hexene/75% Dodecane
50% Hexene/50% Dodecane
75% Hexene/25% Dodecane
100% Hexene

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5.2 Droplet Sizing with Alternative Fuels 
129 
would suggest similar changes in SMD with incremental composition variation could 
be expected, it should be noted that changes in flash points [245, 246, 247] and boiling 
points [248, 249] for binary mixtures are not linear. However, due to limitations in 
experimental repeatability, the effect of this was not reflected in the results. 
Additional investigation into the effect of fuel temperature on dodecane and 
hexene was carried out. For these sets of experiments only a 50/50 binary blend of 
hexene and dodecane was studied. All sprays were carried out at 110bar injection 
pressure. For hexene temperature was increased to within 20 °C of fuel boiling, for the 
50/50 mixture to the boiling temperature of hexene and for dodecane to the maximum 
system capability of just under than 90 °C. The fuel temperature was measured with 
a K-type thermocouple placed through the injector cap into injector reaching just 
behind the needle mechanism to give the most accurate reading during the 
experiments. 
Dodecane and hexene SMD dependence on temperature is presented in Figure 
5.14. For both pure fuels and the 50/50 mixture, a larger temperature increase is 
necessary to produce a similar reduction in SMD as for diesel. 
Figure 5.14: Temperature dependence of hexene and dodecane fuels in pure and 50% 
binary blend form on SMD at minimum transmission 
Table 5.2 demonstrates closeness of hexene (and dodecane to an extent) 
properties to that of gasoline rather than diesel. This is especially evident in their 
density and carbon chain length. Viscosity measurements displayed in the following 
sections further validate this claim. Wang and Lefebvre [250] found, when comparing 
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