1.1  Introduction and Intent.

The intent of this FAQ is to provide some basic information on gasolines and
other fuels for spark ignition engines used in automobiles. The toxicity and 
environmental reasons for recent and planned future changes to gasoline are
discussed, along with recent and proposed changes in composition of gasoline.
This FAQ is intended to help readers choose the most appropriate fuel for 
vehicles, assist with the diagnosis of fuel-related problems, and to 
understand the significance of most gasoline properties listed in fuel 
specifications. I make no apologies for the fairly heavy emphasis on 
chemistry; it is the  only sensible way to describe the oxidation of 
hydrocarbon fuels to produce energy, water, and carbon dioxide.

1.2  Acknowledgements.

Thanks go to all the posters in sci.energy and rec.autos.tech who spend
valuable time responding to questions. I would also like to acknowledge
the considerable effort of L.M.Gibbs of Chevron, who has twice spent his 
valuable time courteously detailing errors and providing references 
for his corrections. All remaining errors and omissions are mine.

1.3  Abbreviations.

AKI = Antiknock Index of Gasoline ( (RON+MON)/2 )
CI = Compression Ignition ( Diesel )
Gasoline = Petrol ( Yes, complaints were received :-) )
IC = Internal Combustion
MON = Motor Octane Rating
Octane = The Octane Rating of the Gasoline 
RFG = Reformulated Gasoline ( as defined by US Clean Air Act )
RON = Research Octane Rating
SI = Spark Ignition ( Gasoline )