Engine-Design Trends Lead to Increased Demand for High-Octane Gas

Apr 6, 2016

*See informative info-graphs by clicking the photo gallery below

Since 2013, the share of premium gasoline in total motor gasoline sales has steadily increased to 11.3 percent in August and September 2015, the highest share in more than a decade. Although lower gasoline prices may be supporting demand for premium gasoline, the upward trend in sales is more likely driven by changes in fuel requirements for light-duty vehicles (LDV) in response to increasing fuel economy standards, which will have widespread implications for future gasoline markets, accoreding to the U.S. Energy Information Administration (EIA).

The latest Corporate Average Fuel Economy (CAFE) regulations, which were finalized in October 2012, set automaker LDV fleet-wide fuel economy for model years 2017-21 to a range of 40.3-41.0 miles per gallon (mpg), with standards for model years 2022-25 rising to 48.7-49.7 miles per gallon. To meet these standards, automakers are implementing a wide range of technical solutions to improve fuel economy.

These solutions include, but are not limited to, weight reduction, conventional engine and transmission efficiency improvements, better aerodynamics, and further development and sale of hybrids and electric vehicles. One significant trend is engine downsizing coupled with turbocharging, according to EIA.

The octane rating of gasoline is an indicator of its resistance to spontaneous combustion. The higher the octane rating, the greater the resistance to preignition, the fundamental cause of engine knock. Use of higher-octane gasoline can offset the increased risk of engine knock caused by increasing engine compression. This higher octane is the reason why premium fuel has historically been required in performance and luxury vehicles that maximize power and torque.

In model year 2009, turbocharged vehicles accounted for 3.3 percent of new gasoline-fueled LDV sales. By model yearl 2014, their share was more than five times greater, at 17.6 percent of the market. The growth in market share of turbocharged LDVs reflects increased use of turbocharged engines in popular vehicle models. In these cases, the turbocharged models have higher fuel economy and more power than the naturally aspirated engines they replaced or supplemented. This trend is expected to continue, and turbocharged engines are projected to account for 83.3 percent of the LDV market by 2025.