Effect of Gasoline Fuel Additives on Combustion and Engine Performance

 
 

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5.1 Gasoline Spray Investigations with Additives 
116 
 
 
 
 
Chapter 5 
5
 
Droplet Sizing with Additives and 
Alternative Fuels 
Chapter 5 describes the results from an investigation into the fundamental 
effects of fuel additives on GDI spray formation. In Section 5.2, analysis of four single 
component fuels and a base diesel fuel is additionally presented to enable better 
understanding of the effects that fuel additives exhibited on base gasoline. The 
equipment and methods used in the experimental and data analysis are identical to 
those described in Chapters 3 and 4. In Section 5.3, surface tension and viscosity 
measurement analysis and discussion is presented.
5.1
 
Gasoline Spray Investigations with Additives 
The need for better efficiencies and ever increasing government regulation on 
fuels and emissions has made use of fuel additives the norm in modern engines. 
Although often overall benefits are known to result from the use of additives, the 
mechanisms at work are often not understood. This is especially true for recent 
utilisation of DI fuel systems in gasoline engines. The first part of the current study on 
fuel additive effects was to determine the extent to which fuel additives affect the 

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5.1 Gasoline Spray Investigations with Additives 
117 
physical properties of fuels through analysis of fuel sprays under various conditions. 
The following sections will present the findings of the investigations. 
5.1.1
 
Experimental Additives 
Fuel additives used in the current study are mostly in commercial use. The 
categories are as described in Section 2.1: deposit control additives, friction modifiers, 
combustion improvers, drag reducing agents, anti-static additives and carrier fluids. 
Additives are added to base fuel in quantities of parts per million. In current study this 
is equivalent to adding a milligram of additive per litre of fuel. Base gasoline fuel used 
in the study corresponds to European Standards EN228. 
Table 5.1 displays the additives and the labelling system used for experimental 
work. Due to their proprietary nature, it is not possible to disclose the exact
Additive Group 
Additive 
Treat Rate (1X), mg/L 
Anti-Static
Additive 
AS-A 
2 
Carrier
Fluid 
C-B 
100 
Combustion Improvers 
CI-E 
250 
CI-F 
250 
CI-H 
250 
CI-I 
1000 
Deposit Control 
Additives 
DCA-A 
100 
DCA-B 
100 
DCA-C 
100 
DCA-G 
100 
DCA-M 
100 
DCA-N 
100 
Drag Reducing Agents 
DRA 
30 
DRB 
30 
Friction
Modifiers 
FM-A 
100 
FM-N 
100 
FM-O 
100 
Viscosity
Modifier 
Lauric 
diethanolamide 
1000