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A novel high-speed electromagnetic actuator for electronic fuel injection system (EFIS) of diesel engine is proposed in this paper. By using a permanent magnet and an annular flange, the design of the novel actuator aims to overcome the inherent drawbacks of the conventional solenoid electromagnetic actuator, such as high power consumption and so on. A method of multi-objective optimization combined with response surface methodology and Genetic Algorithm (GA) is employed to obtain the optimal design of the novel actuator. First, combined with design of experiments and finite element analysis, the second order polynomial response surface models (SOPRSM) of electromagnetic forces are produced by the least square principle. Second, the complete multi-objective optimization mathematical model (MOMM) of the novel actuator based on SOPRSM is built, aiming to maximize the net electromagnetic force on the armature and minimize the drive current.

Electronic in-line pump system (EIPS) is an electronic controlled fuel injection system which meets China's emission regulations. In this paper, a numerical model of EIPS was developed in AMESim for the purpose of creating a tool for simulation experiments. Experiments were conducted at the same model conditions to validate the model. The results are quite encouraging and in agreement with model predictions which imply that the model can accurately predict the dynamic injection characteristics of EIPS. The design of experiments was performed using a 2-level-5-factor face-centered central composite design (FCCD) method in order to study the interactive effect of factors on fuel injection quantity fluctuation (FIQF). The factors studied were supply fuel pressure, cam linear velocity, control valve lift, needle spring pretightening force and nozzle flow coefficient.

High-speed solenoid valve (HSV) is one of the most critical components of electronic control fuel system for diesel engine, whose dynamic response characteristics have a direct impact on the key performance indicators of diesel engine. For the improvement of dynamic response speed of HSV, a design method of multi-objective optimization based on response surface methodology and genetic algorithm (GA) is employed. Firstly, the finite element model (FEM) of HSV was developed and verified. Secondly, the second order polynomial response surface model (RSM) of the electromagnetic force was constructed by the method of optimal latin hypercube design along with the FEM of HSV, taking the key structural parameters of armature and iron core as variables. Then the multi-objective optimization mathematical model (MOMM) of HSV based on RSM was analyzed and established, taking the electromagnetic force and the mass of armature as objectives.

In this paper we have obtained real-time series of in-cylinder pressure by carrying out some experiments and studied the in-cylinder pressure cycle-to-cycle variations in a diesel engine. By using recurrence plot (RP) and recurrence quantification analysis (RQA), we have investigated the dynamical characteristics of combustion in diesel engine through the in-cylinder pressure cycle-to-cycle variations. The results show that the combustion process exhibits many chaotic features and deterministic nature, the qualitative and quantitative change in combustion can be easily related to patterns in recurrence plots (RPs) and RQA, and combustion system is sensitive to initial conditions. The conclusions of our research work may be helpful in developing effective control strategies to improve diesel engine performance.