Caterpillar and ORNL cooperate on methanol-fueled four-stroke R&D

The ORNL and Caterpillar collaboration focuses on a four-stroke internal combustion marine engine that will be modified to run on methanol at the Department of Energy’s National Transportation Research Center. The research supports efforts to decarbonize the marine industry by using alternative fuel sources. [Photo: Genevieve Martin, ORNL/U.S. Dept. of Energy]

The U.S. Department of Energy’s Oak Ridge National Laboratory (ORNL) and Caterpillar Inc. have entered into a cooperative research and development agreement, or CRADA, to investigate marine methanol-fueled four-stroke engines.

While methanol has been much in focus as a fuel for large, two-stroke powered oceangoing vessels, the availability of methanol-fueled four=strokes could see its adoption across a broad range of vessel types. ORNL, which categorizes the marine industry as a hard-to-electrify transportation sector, says that methanol is an attractive fuel alternative to diesel as it reduces carbon emissions and also reduces emissions of nitrogen oxides and sulfur oxides. In addition, its relatively high energy density makes it easier to store on marine vessels than gaseous fuels meaning it can be more easily integrated into overall existing engine design and operation.

However, methanol is more difficult to ignite than diesel. Under the terms of the CRADA, ORNL researchers will work with Caterpillar over the next few years to identify, develop and test hardware configurations and operating strategies required to maximize use of methanol in engines retrofitted for methanol.

Research will be conducted on a Caterpillar in-line six-cylinder marine four-stroke engine that has been modified for methanol use and installed at DOE’s National Transportation Research Center at ORNL.

New methanol-fueled four-stroke engine designs will also be considered, and several engine combustion strategies will be explored including dual-fuel, dimethyl ether reforming and spark-ignited prechambers. Caterpillar will support ORNL by providing additional materials and research expertise to enable engine performance, efficiency and durability while reducing GHG and other emissions.

“We look forward to working with Caterpillar to develop near-term combustion strategies that can be retrofitted on existing engines to realize immediate reductions in carbon emissions. We also will develop long-term combustion strategies for new engine technologies that achieve 100% displacement of diesel fuel with methanol,” said ORNL’s Jim Szybist, section head for propulsion science. “The research we conduct over the next few years will be a significant contributor to decarbonization efforts globally.”

The project supports DOE’s Vehicle Technologies Office’s focus on reducing GHG emissions from off-road vehicles included marine vessels. These sectors are significantly more challenging to decarbonize than on-road, light-duty transportation applications and require unique solutions.

“Caterpillar is proud to be working with ORNL as we develop the technology for a lower carbon future,” said Brad Johnson, vice president of Caterpillar Marine. “Our marine customers across the U.S. have been clear that methanol will play a key role in their journey to net-zero emissions. The maritime industry has unique challenges that can’t necessarily be met by technologies being developed for other transportation sectors, so it is important to have this collaboration with ORNL to accelerate the technology and set the path for the future/“