Effect of Gasoline Fuel Additives on Combustion and Engine Performance

SM
D,
 µm
Pressure, bar
Base
1X
10X
Base After

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5.2 Droplet Sizing with Alternative Fuels 
123 
Figure 5.8: SMD for gasoline with FM-O at minimum transmission 
5.2
 
Droplet Sizing with Alternative Fuels 
This section describes droplet sizing results with fuels other than gasoline and 
gasoline additives. Previous work with gasoline bound additives showed that very 
little if any effect can be seen from usage of additives. Since it is essential to 
understand effects from various sources under varying conditions on fuel sprays, it 
was deemed useful to carry out further tests to see what and to what extent does affect 
fuel atomisation. The droplet size analysis was carried out under the same conditions 
as described Chapter 4. 
Moreover, temperature effect of some fuels and binary mixtures was 
investigated. Due to the effect of temperature on fuel viscosity and surface tension and 
its effects in turn on SMD. Overview of the fuels tested is given in Table 5.2. 
5.2.1
 
Diesel Fuel 
Among alternative fuels investigated was diesel fuel. Globally, it is estimated 
that 2/3 of all new passenger cars are diesel vehicles [240] and consequently it was 
considered valuable to compare diesel sprays under identical conditions to gasoline 
sprays. Diesel fuel was tested at injection pressures of 50-120 bar and SMD 
measurements taken at minimum and 50% transmission instants. In addition, 
temperature effect on SMD was investigated. This was carried out to study the effect 
of viscosity change on SMD. Whilst evaporation rates are bound to be affected by
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