Review of Selected Fuels Used and with Potential for Fueling Compression-Ignition Engines

This paper reviews selected biofuels that are currently in use, as well as fuels considered promising, for powering compression-ignition (CI) engines, including Common Rail systems. The review focuses on fuel properties, production pathways, operational compatibility, and the effects on engine performance and exhaust emissions. The objective is to systematize the current state of knowledge on biodiesel, hydrotreated vegetable oil (HVO), biomass-to-liquid (BtL), F-34, and sustainable aviation fuel (SAF), and to identify their key advantages, implementation constraints, and research gaps relevant to transport and power-generation applications. The paper compiles and compares published studies on fuel production routes and on the consequences of fuel use in CI engines with respect to performance and pollutant emissions. As an outcome, the available evidence is synthesized, fuels with the highest implementation potential are indicated in the context of emission reduction while maintaining required operational functionality, and priority areas for further research are highlighted, including the still insufficiently characterized effects of SAF on CI engine operation and emissions.