Effect of Gasoline Fuel Additives on Combustion and Engine Performance

T
ra
ns
m
is
sio
n, 
%
Pressure, bar
16 Degrees
20 Degrees
25 Degrees

---

5.2 Droplet Sizing with Alternative Fuels 
126 
transmission levels seem to flatten out. It should be pointed out that this behaviour 
was not seen in gasoline fuels where the transmission levels decreased evenly 
throughout the pressure range. 
In order to obtain better understanding of fuel viscosity changes, experimental 
values for diesel viscosity changes with temperature, as found by Esteban et.al. [241], 
were compared to the temperatures obtained in current experiments. This can be seen 
in Figure 5.11. It shows that viscosity can be estimated to reduce by at least 10 % with 
each of the temperature increases. This would suggest at 50 bar injection pressure, a 
20 % decrease in fuel viscosity is followed by a decrease of 7.1 % in SMD. At higher 
pressures a general trend of even larger SMD decreases with increased temperature 
seems plausible. 
Figure 5.11: Comparison of diesel fuel viscosity dependence on temperature and estimated 
Malvern measurements conditions 
5.2.2
 
Mixtures of Single Component Fuels 
Several pure fuels were investigated in order to see effects of fuel carbon chain 
length and molecular structure. Additionally experiments were carried out on 
temperature effects and binary blends on SMD. All mixtures were prepared by 
volume. Experiments on hexene and dodecane were carried out to investigate effects 
of carbon chain length and hence volatility on SMD. Additional mixtures at 25 %, 50 
% and 75 % hexene were analysed. Hexene boiling point is about a third of that of 
dodecane and it was expected to produce smaller droplets as a consequence of 
1
2
3
4
5
6
7
0
10
20
30
40
50
60
70
80