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In order to improve the efficiency and quality of a permanent magnet synchronous generator (PMSG) for vehicles, the parametric model and finite‐element model of the generator are established. The influence of seven structure parameters on three performance parameters is obtained by simulation analysis, and the sensitivity values of the parameters are given. According to the simulation results, it can be seen that the structure design parameters have higher degrees of freedom, and the relationship among parameters is complex. Using three multidimensional functions as test functions, the precision of the fitting method proposed in this paper is compared with that of the traditional methods. The test results show that, compared with the other methods, maximum projection (MaxPro) sampling and the Kriging method can select as fewer samples as possible while guaranteeing the higher fitting precision. Then, the Kriging surrogate model, which reflects the nonlinear relationship between the structure and performance parameters, is established, and the prediction precision of the model is verified. Based on the surrogate model, the performance of the generator with three performance parameters as optimized objects is optimized by use of elitist nondominated sorting genetic algorithm (NSGA‐II), and a Pareto optimal solution set of the objective function is obtained. Three of the optimal solutions are selected for finite‐element verification. The results show that the Kriging surrogate model can provide better global and local prediction between input and output variables. It is further proved that the samples obtained by MaxPro sampling can fully reflect the characteristics of the design space. The optimized objects can be weighed according to the optimal decision based on the results of multiobjective optimization through the Kriging surrogate model. The effectiveness of the optimization method is verified. It is of great engineering significance to improve the performance of generators, and the optimal model obtained by this method has an important reference value for prototype trial production. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

A technology roadmap of EGR + DOC + DPF for reducing diesel vehicle emission is adopted for a light-duty diesel vehicle of Foton. A compound regeneration scheme of FBC + burner + DOC for DPF is devised, and a 100,000 km durability test is conducted. The changing law of the filtration efficiency of DPF and the effects of ash on filter are analyzed and the effects of engine emission deterioration and DOC aging on CO and HC emissions are compared. The results of test show that the aging of DOC can lead to excess emission and is the bottleneck of system application. [ABSTRACT FROM AUTHOR]

The mathematical model for the pressure drop of wall-flow diesel particulate filter (DPF) is established and verified by test. Through a simulation with the model, the effects of filter structural and operating parameters on exhaust back pressure (EBP) are analyzed. The results show that the increases in the diameter and length of filter have positive effects on reducing EBP, the smaller length/diameter ratio of filter can further reduce EBP while increasing the wall thickness of filter may make it rise; The reasonable increase in filter's channel number per unit cross section is conducive to the reduction in pressure drop of filter with particulates cumulated, but overdoing will cause reverse effects in thicker filter wall; With particulate cumulating in filter increasingly, the EBP goes up slightly more than linearly; The rises in both exhaust flow and temperature may increase EBP with the effect of exhaust temperature on EBP more obvious in higher exhaust flow, and the EBP rises as the exhaust flow increases with a higher rising rate in heavier soot deposit. [ABSTRACT FROM AUTHOR]

The main principles to determine the right moment for the regeneration of diesel particulate filter (DPF) is proposed, the features of different judgment methods on regeneration schedule are compared, and the numerical simulation and experimental study on the pressure drop of filter are carried out. Then a new judgment scheme on regeneration schedule is proposed, in which the right time for DPF regeneration is determined by calculating particulate matters deposition according to the flow rate, temperature and back pressure of exhaust gas, based on the pressure drop model for filter. The results of study show that the soot mass limit is 4g/L for cordierite filters and 8g/L for SiC filters, without considering the specific regeneration control strategy. [ABSTRACT FROM AUTHOR]