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Fuels Performance

This is the September 2016 issue of the Transportation and Hydrogen Newsletter.

September 26, 2016

A photo of a worker using a small crane to lift a cylindrical tank.

Compressed natural gas (CNG) tanks, such as those shown above, should be retired from service following a safety protocol and manufacturers' instructions, according to NREL's CNG tank decommissioning video.

Video Promotes Safe CNG Tank Decommissioning Practices
A video on CNG fuel tank defueling, decommissioning, and disposal, developed by NREL as part of the lab's safety assurance work, is being used to instruct transit agencies and others about safe CNG tank end-of-life practices. The video was previewed at the American Public Transit Association's Clean Propulsion and Support Technology Committee meeting in May and showcased at the National Clean Cities Coordinator Training Workshop in August.

Evaluating Biodiesel Performance in Modern Engines

NREL is working cooperatively with the National Biodiesel Board on research that assesses several aspects of biodiesel compatibility with engines, vehicles, and fuel-handling infrastructure. Several cooperative studies were recently conducted that examined how biodiesel performs with new diesel emission controls technology, how it affects engine-out nitrogen oxide and diesel particulate filter performance, and how it can be stabilized for longer-term storage. The results are detailed in the report Biodiesel Performance with Modern Engines.

Fuel Combustion Lab Escalates Research Capabilities

Two new additions to NREL's Fuel Combustion Laboratory considerably increase capabilities to characterize fuels at the molecular level and predict a fuel's effect on engine performance and emissions. The Advanced Fuel Ignition Delay Analyzer expands the lab's capacity to screen small quantities of fuel compound candidates. The Fuel Ignition Tester furthers the development of novel fuel-ignition experimental techniques that complement existing engine-based methods. Both pieces of equipment serve as constant-volume combustion chamber platforms for fuel-ignition kinetics research.

Co-Optima Wraps Up First Year of Landmark Initiative

The Co-Optimization of Fuels & Engines (Co-Optima) initiative, a DOE effort in collaboration with eight other national labs, wrapped up its first year with a webinar providing an in-depth overview of the project and its progress. In this inaugural year, researchers surveyed hundreds of bio-derived blendstocks to identify more than 40 molecules/mixtures with properties beneficial to advanced spark-ignition engines, and analyses are underway. Simultaneous engine experiments were used to refine an engine merit function, and detailed combustion simulations have been initiated.

Biofuel: What Formula is Best for Spark-Ignition Engines?

Government-mandated increase in the use of renewable fuels, such as that derived from biomass, is driving NREL research to improve the efficiency of such fuels in direct-injection spark-ignition engines. In one NREL study, different biomass-derived oxygenates were blended in various levels with gasoline, and the impact on knock resistance and fine particle emissions was examined. The outcomes of the study, presented in a recent paper, provide fuel properties and performance data to help improve the efficacy of biofuels.

Publications Page and Website Serve Up Fuel-Specific Resources

The U.S. Department of Energy's Clean Cities program publications web page and its sister website, the Alternative Fuels Data Center (AFDC), offer users a wealth of current information about alternative fuels and vehicles. Among the most popular publications are the fuel-specific fact sheets, such as the recently published Propane Basics and Natural Gas Basics fact sheets and the At A Glance: Electric-Drive Vehicles brochure. The AFDC website is dedicated to alternative transportation fuels, including those just now emerging in the transportation sector.

Assessment of ASTM Biodiesel Standard Yields Positive Results

As part of its ongoing research on oxidation stability, NREL verified the accuracy of ASTM International specifications for biodiesel stability brought into question by new high-pressure common-rail fuel systems that subject diesel fuels to higher temperatures and pressures. As reported in a recent paper, after exposure to high temperatures and high pressures, relatively few signs of fuel degradation or instability were observed, providing a measure of confidence that the ASTM requirement supplies adequate protection for modern fuel systems.

Learn more about NREL's Transportation RD&D including Fuels Performance and Hydrogen and Fuel Cells, as well as partnership opportunities.