Multi-objective optimization of fuel injection performance of a common rail injector

The improvement of injector performance is important for the operation of common rail (CR) fuel systems. In this study, the optimization work has been carried out on a large-flow common rail injector. First, to simulate the injection process, a one-dimensional (1-D) model was developed and validated against the experimental data. The mathematical approximation model was also established to correlate the injection performance with the factors. Then, a multi-objective model by taking three design objectives into account was established and solved. Finally, Pareto front was obtained and the final optimization solution was determined. Furthermore, an extensive validation and analysis for the optimized results under various operating conditions was also carried out. Results shows that the three objectives, total response time, injection pressure fluctuation and injection pressure drop respectively, are improved by 11.75%, 39.12%, and 10.03% under the typical condition. And the proposed multi-objective optimization program based on design of experiment (DOE) technique, response surface methodology (RSM) and Elitist Non-dominated sorting genetic algorithm (NSGA-II) in present work can exhibit a good capability to optimize the problem of the injection performance in a CR fuel system.