While a few automotive executives would like to see octane boosted in gasoline, the U.S. Environmental Protection Agency (EPA) likely won’t be looking at it for years.
Dan Nicholson, General Motors’ vice president of global propulsion systems, said that GM could boost fuel economy in most engines by about 5 percent if U.S. fuel had the same higher octane gasoline as what’s being used in Europe. That comment was made during a conversation with Automotive News technology and engineering reporter Richard Truett, who examined how automakers and the EPA are looking at it.
The EPA sees that potential, but thinks nothing will be moving forward on it until after 2025 when new fuel economy and emissions standards take effect. Shaping that policy change is likely to be a few years out, but lobbying by automakers is starting to be noticed, Truett said.
Regular and premium gasoline grades are four to six octane lower than comparable grades of European gasoline, but the calculations are different and difficult to compare. American gasoline octane is calculated using averages from RON (research octane number) and MON (motor octane number). That’s done differently in Europe; for example in Germany, regular gasoline is usually 95 octane and premium is 100. It’s based on the RON scale in Germany.
Octane is based on measuring how much compression fuel can tolerate before it ignites. For automakers in the U.S. market, higher octane can raise engine compression ratio and increase power output. The ability to increase that output allows engineers reduce engine size and cut vehicle weight.
Ford’s EcoBoost engines, especially the one powering the F-150 pickup, highlight that potential. The latest 3.5-liter twin-turbo V-6 engine produces more power many of Ford’s previous big block V-8 engines.
Chris Grundler, director of the EPA’s office of transportation and air quality, recently said at an automotive conference that the agency does recognize fuel has a part to play in the auto industry meeting tougher standards.
Grundler said the EPA has been collecting data about the potential for higher octane gasoline to reduce emissions.
“After 2025, we should talk about what the future fuels should look like and what is the optimum mix of vehicle and fuel technologies,” Grunder said during the conference. “It is not as simple as the automakers might think it is under the law, and we have to follow the law. We have had requests to regulate octane for many years.”
Making policy on octane levels is still fairly new for EPA, Grundler said. The agency didn’t address it until 2007 when the Supreme Court ruled that greenhouse gases are harmful. Since then, it hasn’t been as easy as asking engineering experts to agree on a set level for higher octane ratings.
“For us to intervene and set fuel standards, we need to show that there is an air quality benefit or that, absent regulations, that it is somehow inhibiting the after-treatment or other parts of the vehicle. And that the benefits outweigh the costs,” Grundler said.
Using more ethanol to increase octane is one method used, but it’s not guaranteed to accomplish intended results. One concern automakers express is that ethanol replacing gasoline is less energy dense, and higher concentrations of ethanol require automakers to make changes to a vehicle’s fuel systems. These concerns come up during debates over whether E15, with 15 percent ethanol and 85 percent gasoline, is going to work well in engines.
While some ranking powertrain and engineering executives champion increasing octane, their corporations tend to stay out of it, Truett said. Their main concern comes from using higher octane driving up gas pump prices, which makes car owners complain.
Truett believes that increasing octane would be washed out in fuel prices over time. An example he cites comes from introduction of sulfur to diesel fuel a decade ago. The oil industry cried out that diesel prices would be skyrocketing, but lately its been costing less than regular gasoline around the country.
He predicts that once the octane issue enters the spotlight, the EPA will hear from automakers, oil refiners, the ethanol industry, environmentalists, consumer groups, and others. None of them want their business models and lives disrupted, Truett said.