AUTHOR=Guo Hongsheng , Li Hailin , Guzzella Lino , Shioji Masahiro TITLE=Editorial: Advances in Compression Ignition Natural Gas–Diesel Dual-Fuel Engines JOURNAL=Frontiers in Mechanical Engineering VOLUME=7 YEAR=2021 URL=https://www.frontiersin.org/journals/mechanical-engineering/articles/10.3389/fmech.2021.642187 DOI=10.3389/fmech.2021.642187 ISSN=2297-3079