Abstract
Two gasoline turbocharged direct injection (GTDI) and two diesel soot-in-oil samples were compared with one flame-generated soot sample. High resolution transmission electron microscopy imaging was employed for the initial qualitative assessment of the soot morphology. Carbon black and diesel soot both exhibit core-shell structures, comprising an amorphous core surrounded by graphene layers; only diesel soot has particles with multiple cores. In addition to such particles, GTDI soot also exhibits entirely amorphous structures, of which some contain crystalline particles only a few nanometers in diameter. Subsequent quantification of the nanostructure by fringe analysis indicates differences between the samples in terms of length, tortuosity, and separation of the graphitic fringes. The shortest fringes are exhibited by the GTDI samples, whilst the diesel soot and carbon black fringes are 9.7% and 15.1% longer, respectively. Fringe tortuosity is similar across the internal combustion engine samples, but lower for the carbon black sample. In contrast, fringe separation varies continuously among the samples. Raman spectroscopy further confirms the observed differences. The GTDI soot samples contain the highest fraction of amorphous carbon and defective graphitic structures, followed by diesel soot and carbon black respectively. The AD1:AG ratios correlate linearly with both the fringe length and fringe separation.
Highlights
Due to increasingly stricter emission regulations, automotive companies strive for new ways to optimize internal combustion engines
Two gasoline turbocharged direct injection (GTDI), two diesel engines, and one carbon black sample were analysed for their nanostructure characteristics:
While the diesel samples only diverge slightly from the highly ordered carbon black, the GTDI samples show a greater diversity in structure types
Summary
Due to increasingly stricter emission regulations, automotive companies strive for new ways to optimize internal combustion engines. Uy et al [18] observed similarities in the morphology between diesel and GTDI soot samples The latter exhibited higher concentrations of wear metals and oil additives, as well as some regions with a sludge-like structure. Following initial advances by Vander Wal et al [38] towards quantitative measurements, Yehliu et al [39,40] developed an algorithm comprising image processing and geometric analysis of the fringes with improved quality Using this algorithm, Jaramillo et al [41] identified the fringe length and tortuosity for soot from a diesel powered industrial forklift to be 1 nm and 1.17 respectively, while fringe separation was not. The effect of sample cleaning procedures on the data quality was assessed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
