The two-stage injection processes of three fatty acid esters, methyl laurate, methyl oleate and ethyl oleate, were investigated and compared with that of fossil diesel using a high-pressure diesel engine common rail injection system. The injection characteristics studied included injector inlet pressure characteristics, and rate and quantity of fuel mass injected per cycle. The effects of fuel properties and injection dwell time between the pilot and main injection events were also considered. Differences in the fuel properties of diesel and fatty acid esters caused modest changes in the main injection quantities and fuel pressure fluctuation characteristics after the end of injection, and the changes were affected by different injection pressures. The injection dwell time was also found to influence the injector inlet pressure characteristics at the start of the main injection event and thus the amount of fuel injected during main injection was slightly changed. (C) 2015 Elsevier Ltd. All rights reserved.