The optimization of power parameters is the key to the design of pure electric vehicles. Reasonable matching of the relationship between various parameters can effectively reduce energy consumption and achieve energy sustainability. In this paper, several vehicle performance indexes such as maximum vehicle speed, acceleration time and power consumption per 100 km were used as optimization target vectors, and transmission ratio was used as optimization variable to establish the optimization problem of parameter matching. Then, the feasible domain of the transmission ratio was obtained by taking the lowest performance index of the vehicle as the constraint condition. In the feasible domain, the multi-objective genetic algorithm is used to solve the optimization problem. The Pareto optimal solution set is obtained for fixed ratio transmission and two-gear transmission, which is used as an alternative solution set. The final parameter-matching scheme is determined by comparing the alternative scheme set of different motors comprehensively. The results show that the competition relationship between multiple optimizable indexes can be described effectively by solving the Pareto front. Specifically, the Pareto optimal solution set for the motor A + fixed transmission scheme is 1.33~1.85; the Pareto optimal solution set for the motor A + 2 transmission scheme is [1.72, 0.98]~[2.99, 1.57], and the Pareto optimal solution set for the motor B + 2 transmission scheme is [2.99, 1.40]~[2.99, 1.57]. The motor A + fixed transmission scheme does not require A clutch and does not require designing a shift algorithm. Therefore, after comprehensive consideration, the motor A + fixed transmission ratio transmission scheme is set as the final scheme.

In this paper, based on the coupling calculation of Simulink software and GT-Power software, an Optimizer model method was proposed for a 16V265H diesel engine to study the effects of different ratios of biodiesel (B0, B10, and B20) on the performance of a 16V265H diesel engine at 1000 rpm and 75% load. Firstly, the four parameters of diesel engine power, BSFC, soot emission, and NOx emission were taken as the result variables of the optimization model. Taking the intake and exhaust timing of the diesel engine as the independent variable of the optimization model, the maximum power, minimum BSFC, and minimum diesel engine emission were studied and analyzed. Finally, the performance parameters were comprehensively analyzed to determine the best intake and exhaust valve timing. Moreover, based on the model optimization, the diesel engine’s BSFC and power performance were compared, and the optimal intake timing scheme for the diesel engine with different biodiesel ratios at 75% operating conditions was obtained. The results showed that the maximum power, optimum BSFC, and minimum emissions of the 16V265H diesel engine with different ratios of biodiesel and different intake valve timing angles were also different. Under 75% load conditions, the BSFC reduction rate was up to 6.32%, and the power increase rate was up to 5.87%. In addition, by optimizing the model with B10 biodiesel and the intake valve timing close to 202°CA and the exhaust valve timing close to 98°CA, the diesel engine had the lowest NOx emission; with B10 biodiesel and the intake timing at 180°CA, the diesel engine had the lowest BSFC; and with B10 biodiesel and the intake valve timing close to 179.5°CA, the diesel engine had the maximum power. In conclusion, the diesel engine is best with B10 biodiesel. This research method can provide a reference for implementing variable intake system technology for the 16V265H diesel engine.

In this paper, the simulation model was established based on GT-Power software, and a scheme using the Miller cycle based on biodiesel was proposed. Taking diesel engine 16V265H as the research object, the accuracy of the simulation model was verified by experiments. Combined with the comparison of physical and chemical characteristics of biodiesel and the experimental analysis of biodiesel under three different combinations, it was concluded that low ratio biodiesel was the best choice to meet the power, economy, and emission performance of diesel. Through the simulation scheme of the two Miller cycles for pure diesel (B0) and biodiesel (B10) under different load conditions at 1000 rpm, the NOx emission performance of pure diesel in a Miller cycle was significantly improved. On this basis, the comprehensive performance of the two Miller cycles was compared with biodiesel. The results showed that both the Miller cycles could reduce NOx emission. Combined with other key performances of a diesel engine, the best scheme to improve the performance of the diesel engine was to burn B10 biodiesel and overlap angle the Miller cycle of the variable valve at 30 °CA. The scheme has guiding significance for the application of the 16V265H diesel engine.

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This paper introduces the theoretical basis and optimization method of diesel engine working process theory. By comparing two Miller cycle schemes of B20 biodiesel under different load conditions of 1000 rpm (100%, 75%, and 50%), the best Miller cycle scheme and the best Miller degree were found. Then, based on the Miller cycle scheme, its performance was optimized and analyzed, and the best intake timing scheme of the B20 biodiesel engine under different working conditions was obtained. The results show that the performance of B20 biodiesel in variable valve overlap angle Miller cycle is better than that in variable cam profile Miller cycle, and the effect is the best when the Miller degree is 30 °CA. When B20 biodiesel is used under 100% and 50% load conditions, the maximum power under the two loads is in the area near intake valve timing 179 °CAA and exhaust valve timing 174 °CAA, and intake valve timing 224.5 °CAA and exhaust valve timing 119 °CAA, respectively. Fuel consumption, soot emissions, and NOx emissions also have the corresponding best performance intake valve and exhaust valve positions.