Methodology for the validation of fuel consumption in diesel engines installed on board military ships, using diesel oil and biodiesel blends

Maritime transport accounts for 90% of global trade, and therefore, the levels of air pollution from ships are high. In this respect, MARPOL 73/78 suggests the use of biodiesel in diesel engines installed on board ships as an alternative in order to reduce emission levels, while still ensuring torque and power supply, for which they were designed. In this regard, the contribution of this work is to present a methodology for the prediction of biodiesel blend consumption in engines installed on board military ships. For this purpose, a one-dimensional, quasi-steady thermodynamic model was developed, comprising a diesel engine operation cycle. Since biodiesel has lower heating value than diesel oil, fuel consumption increases, so the nonlinear Levenberg–Marquardt optimization technique was used to evaluate the injection duration. The method implemented was validated using statistical tools, with experimental data obtained in a direct injection single-cylinder diesel engine, installed on test bench, using several soybean biodiesel blends, and the results showed good accuracy related to performance parameters. Finally, a direct injection diesel engine with common rail installed in a military ship was chosen as case study, and the results demonstrated that in order to maintain engine performance, fuel consumption increases as the biodiesel content increases in the blend.