Unambiguous Identification of Key Molecular Species in Deposits Responsible for Increased Pollution from Internal Combustion Engines

Abstract

<div>Clean and efficient internal combustion engine performance will play a significant role in</div><div>the move to a decarbonized energy system. Currently, fuel deposit formation on engine</div><div>components negatively impacts CO2 and pollutant emissions, where previous attempts at</div><div>deposit characterization afforded non-diagnostic chemical assignments. Here, we uncover</div><div>the identity and 3D spatial distribution of molecular species from gasoline, diesel injector</div><div>and filter deposits with the 3D OrbiSIMS technique. Alkylbenzyl sulfonates, derived from </div><div>lubricant oil contamination in the engine fuel cycle, were common to samples, we</div><div>evidence transformation of the native sulfonate to longer chain species by reaction with</div><div>fuel fragments in the gasoline deposit. Inorganic salts, identified in both diesel deposits,</div><div>were prevalent throughout the injector deposits depth. We identified common polycyclic</div><div>aromatic hydrocarbons up to C66H20, these were prevalent in the gasoline deposits lower</div><div>depths. This work will enable deposit mitigation by unravelling their chemical</div><div>composition, spatial distribution, and origins.</div>