Concerns over U.S. gasoline octane requirements and benefits have again captured the industry spotlight.
American Petroleum Institute says U.S. motorists are not buying more octane in their gasoline than their vehicles need.
According to a new API study, "Americans buy more regular and less midgrade gasoline than the vehicle fleet technically requires but about the right amount of premium gasoline."
Study parameters
To determine the octane requirements of vehicles, the study relied mainly on data collected by the Coordinating Research Council, a nonprofit organization supported by the oil and auto industries. It determines gasoline octane requirements using statistical surveys and laboratory tests under specified conditions such as temperature, barometric pressure, and humidity. The API study also used data from the American Automobile Manufacturers Association and the Department of Energy.
The research compared octane requirements with market shares and recognized the influence of economic variables in motorists' fuel purchases. It also examined the significance of recent vehicle engine changes, such as the growing use of knock sensors, and the growing percentage of utility vehicles, vans, and light trucks in the U.S. auto fleet.
The study concluded vehicle octane requirements are estimates subject to uncertainty due to manufacturing tolerances, variations in driving circumstances, and the growing prevalence of knock sensors. Actual vehicle performance experience may deviate from octane recommendations contained in owners' manuals.
It said knock sensors and altitude compensators have changed the consequences of engine knock, which in turn may have contributed to the "overbuying" of regular gasoline and the "underbuying" of midgrade gasolines.
Octane buying patterns
The study said motorists' purchases of gasoline grades roughly match vehicle octane requirements.
"However, regular grade gasoline sales account for almost 68% of the market, while an estimated 62% of the vehicles have octane requirements satisfied by regular grade gasolines.
"By contrast, 19% of the vehicles are estimated to require midgrade gasolines while the midgrade market share is only 12%. Premium grade sales account for 20% of the market, and about 19% of the vehicles in use require premium gasolines."
The study found market share of regular grade gasolines jumped sharply as a result of temporarily higher prices during the l990-91 Persian Gulf crisis and the economic recession of the early 1990s. The market share of premium gasolines fell and did not recover.
It noted the content and effectiveness of gasoline additives differ from brand to brand, and some premium grades contain bigger doses of additives than regular and midgrade gasolines. These differences can affect vehicle performance.
API also said, "Overbuying of premium gasolines is not prevalent, if it occurs at all. It said about a fifth of the vehicles in use need more octane than they are provided by midgrade fuels and approximately one fifth of gasoline sales are premium grade."
Copyright 1996 Oil & Gas Journal. All Rights Reserved.
