Reactivity of Novel High-performance Fuels on Commercial Three-way Catalysts for SI Engine Emissions Control

Josh  Pihl, Oak Ridge National Laboratory

Reactivity of Novel High-performance Fuels on Commercial Three-way Catalysts for SI Engine Emissions Control

Josh Pihl, Sreshtha Sinha Majumdar, and Todd Toops

National Transportation Research Center, Oak Ridge National Laboratory

 

 

The Department of Energy (DOE) “Co-Optimization of Fuels and Engines” initiative aims to simultaneously develop novel high-performance fuels along with highly efficient engines to reduce petroleum consumption. For light-duty gasoline-fueled vehicles operating under stoichiometric conditions, commercial three-way catalysts (TWC) are extremely effective at meeting the stringent emissions regulations on deleterious pollutants such as nitrogen oxides (NOx), carbon monoxide (CO) and non-methane organic gases (NMOG). However, most of the regulated pollutants escape from the vehicle exhaust under cold-start conditions when the TWC is below the critical light-off temperature. Thus, commercialization of these advanced engines operating on the novel high-performance fuels is dependent on cold-start compliance with the U.S. EPA regulations.

We have conducted an extensive study on the reactivity of pure high-performance fuels on a hydrothermally-aged TWC under synthetic engine-exhaust conditions to select candidate fuel blendstocks with promising light-off characteristics to mitigate cold-start emissions. The results from our studies revealed interesting and important catalyst light-off trends based on the functional groups of the fuels investigated such as alkanes, alkenes, alcohols, ketones, esters, aromatic ethers, and non-oxygenated aromatic hydrocarbons. As real-world fuels are multi-component blends, the TWC light-off temperatures were also measured for 10-30% (by vol.) of the selected blendstock candidates blended into a surrogate blendstock for oxygenate blending (BOB). The impact on the CO and NOx conversions based on the fuel light-off characteristics will also be presented.