Description: Gasoline is a complex
mixture of hydrocarbon-based components and additives that are
specifically formulated for different climates and conditions. The
properties of any given blend of gasoline must deliver good engine
performance under a wide range of operating demands. Gasoline
quality guidelines have been established by the American Society for
Testing and Materials (ASTM) and are considered the minimum for a
gasoline to be offered on the market. Companies often go beyond the
guidelines to provide more unique formulations to meet specific
motorist needs. Because of the Clean Air Act Amendments of 1990,
motorists in some areas of the country have been required to use
"reformulated" gasoline (RFG) to reduce emissions of ozone-forming
(smog) and toxic
air pollutants. The predominant RFG areas lie in California, the east coast, the Chicago/Milwaukee metro area, Dallas/Houston Texas, and a few others. RFG consists of a different blend than regular gasoline to reduce emissions.
Purpose: Quite simply, gasoline
provides the heat energy necessary to power the
engine in most vehicles. Gasoline also contains various additives that
may prevent deposits on fuel injectors and intake valves,
guard against corrosion in the fuel system, and prevent icing of
fuel lines.
Maintenance Tips/Suggestions: As a motorist, the most important
information you need to know refers to a gasoline's anti-knock index
(AKI)—a numerical representation of a gasoline's ability to resist
engine knock, also known as "pinging." The AKI number is an average
of the Research Octane Number (RON) and the Motor Octane Number (MON). This is the number displayed
on the black-and-yellow placard at the gasoline pump. Because of the
averaging effect of the two numbers, you may find
that
your car performs better on
one brand of gasoline with
87 octane than another. It's best to follow your car
manufacturer's AKI recommendation when choosing gasoline, although there is no advantage
to using a gasoline with a higher AKI than
is needed to run without knocking. Generally speaking, the AKI numbers
at the pump reflect the "grades" of gasoline with names attached
to escalating AKI numbers. Hence, "regular", "mid-grade" and "premium." These grades
are somewhat of a misnomer, as they
don't reflect overall better quality as AKI numbers increase; the
numbers reflect only higher anti-knock capabilities.
