(Photo: Ethanol production in Iowa. Credit: National Renewable Energy Lab)
The US Department of Energy just released two new studies related to fuel and engine co-optimization. One study identifies high-octane blendstocks for gasoline to create better performance. The other quantifies the fuel efficiency potential associated with different fuel properties.
Both studies were completed by the DOE’s Co-Optimization of Engines and Fuels initiative (Co-Optima). Launched on October 1, 2015, Co-Optima is an R&D collaboration among the DOE, nine national labs, 13 universities, an external advisory board, and industry partners to transform transportation fuels and vehicle, maximizing performance and energy efficiency while minimizing environmental impact and accelerating adoption of new combustion strategies.
Target applications for Co-Optima’s early-stage research cover the entire on-road fleet. The initiative aims to improve light-duty vehicle fuel economy more than 35% in relation to a 2015 baseline and improve heavy-duty fuel economy by up to 4%, which represents up to $5 billion savings in annual fuel costs.
In addition, the initiative is seeking to provide the market pull for up to 25 billion gallons annual of domestically-sourced fuel. Their goals also include identifying lower-cost pathways to reduce emissions and leveraging diverse American fuel resources.
The study “Fuel Blendstocks with the Potential to Optimize Future Gasoline Engine Performance” identified eight high-octane blendstocks from five chemical families that could produce better performance when blended into gasoline, based on interim results:
- Alcohols: ethanol, iso-propanol, n-propanol, isobutanol
- Ketones: cyclopentanone
- Furans: a 40:60 mixture by weight of methylfuran:2,4-dimethylfuran
- Alkenes: di-isobutylene
- High-aromatics mixtures
These blendstocks “have shown the potential to increase boosted spark-ignition engine efficiency, meet key fuel quality requirements, and be viable for production at commercial scale by 2025–2030,” the Co-Optima report says. The authors noted that this list should not be viewed as final or limiting. “Blendstocks within these five chemical families could be added or removed as more data and information become available.”
Renewable Fuels Association president and CEO Bob Dinneen lauded the Co-Optima study results, saying publicly that they show that “ethanol is a phenomenal source of octane for high-octane fuel blends.” He also highlighted ethanol characteristics, such as high octane sensitivity and heat of vaporization, that make it an attractive component for high-octane fuel blends.
“Pairing advanced internal combustion engine technologies with high-octane, low-carbon fuels like E25 or E30 would be the lowest cost means of complying with increasingly stringent GHG and fuel economy requirements through 2025 and beyond,” Dinneen said. It’s worth underscoring that ethanol production in the US still remains complex and politically-charged.
A second Co-Optima study, “Efficiency Merit Function for Spark Ignition Engines,” presents a new mathematical equation that quantifies the fuel efficiency potential associated with different fuel properties. “The goal of this research is to provide American industry with the scientific foundation needed to maximize vehicle and fuel performance and efficiency, thereby enabling increased fuel economy and more affordable transportation,” the DOE’s announcement says.
For the next phases of the research, Co-Optima plans to validate the potential fuel efficiency improvements through engine testing and the initiative expects to start looking at fuel efficiency gains in heavy-duty diesel engines.
These studies come at a time when companies are seeking news ways to reduce fleet emissions and improve fuel efficiency. Last year Pittsburgh-based Hyliion announced an electric system that can convert long-haul diesel trucking fleets into hybrid ones, promising fuel savings. Tesla teased an all-electric semi-truck line and Nikola Motor Company chose a new manufacturing site for bringing its hydrogen-electric semi-trucks to market.
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