Based on the test data of diesel/natural gas dual-fuel engine, a prediction model of GA-BP neural network was established based on BP neural network and genetic algorithm optimization with engine torque, speed, fuel injection timing, fuel injection pressure, natural gas alternative fuel and excess air coefficient as input parameters, and the brake specific fuel consumption, CO, NO_x, THC emissions and soot emission as outputs, and the predication results were compared with test values for verification. The research results show that GA-BP neural network model has better predictive performance than BP neural network model. The Mean Absolute Percentage Error (M_APE) predicted by the GA-BP neural network model for the five output parameters is less than 6%, and the coefficient of determination R² is greater than 0.97, and the model has high prediction accuracy and generalization ability.

In order to solve the problem of excessive low frequency road noise of a vehicle model, this paper used the dynamic stiffness method of working load identification to derive the correlation between body side force and chassis attachment point transfer function, body attachment point transfer function and bushing dynamic stiffness parameters. On this basis, the road noise simulation model of the whole vehicle was established, and the contribution of the transmission path was analyzed. The torsion beam bushing was identified as the main transmission path. By reducing the stiffness parameters of the bushing, the force on the body attachment point was improved, so as to reduce the noise inside the vehicle. The real vehicle verification results show that the low frequency low dynamic stiffness and high damping hydraulic bushing can improve the low frequency road noise problem in the vehicle, and improve the impact residual vibration performance.

In order to solve the defect of water leakage of the positioning pin of the door trim during the trial assembly stage of a vehicle model, this article searched for the cause from water management of the door system, positioning method of the door trim, sealing structure of the door trim, and seal material. It is found that the positioning pin through the door sheet metal locating hole is impacted by large water flow, and the sealing pad of the positioning pin blocking the sheet metal hole has less compression on the sheet metal, the gravity and impact force of water is greater than the sealing force of the sealing pad, water pushes the sealing pad apart and flows along the sealing pad to the inside of the door trim. The stress and deformation of the foam cushion block of the positioning pin seal of the door trim were studied. Increasing the thickness of the foam cushion block of the locating pin and increasing the support rate of the positioning pin base to the foam cushion block of the positioning pin will increase the compression of the positioning pin seal cushion block to the sheet metal, and make sure the sealing force of the foam cushion block is greater than the thrust of water on it, the defect was thus solved, and the design and verification criteria for the door trim board positioning and water management were optimized.

In order to explore the main cause for exceeding the limit of driver’s right calf injury in European New Car Assessment Program (Euro NCAP) Mobile Progressive Deformable Barrier (MPDB) collision conditions, the driver’s right leg was analyzed by the dummy’s leg injury evaluation method. Through analysis of the test results, it is concluded that the excessive bending moment on the leg is the main cause of exceeding the limit of driver’s calf injury. The mechanism of calf injury and stress process were analyzed, and the pedal displacement was associated with the leg injury index. The results show that the impact of the foot is affected by the deformation of the accelerator pedal, resulting in excessive bending moment of the calf.

In this research, a one-dimensional heat transfer model was built for a specific thermoelectric module to better estimate property of thermoelectric generator and optimize structure. The three-dimensional flow field and heat transfer models were also established for different thermoelectric generator structures, those two models were coupled to realize the direct display of power output of thermoelectric generator. Based on the coupled models, thermoelectric generators with four different structures were compared and analyzed. The results show that, under the conditions of exhaust gas temperature 523 K and flow rate 0.02 kg/s, the maximum net power output of the heat exchanger structure with staggered fins and a fin spacing of 10 mm and an angle of 8° is 133 W, which is about 14% higher than that of the basic control group with neatly arranged fins and no angle of opening.

In order to analyze the properties of tire effective rolling radius and load radius, the uniform design method was used to test the effective rolling radius and loaded radius under different conditions. The results show that the trend of the rolling radius and load radius affected by speed, air pressure and load is basically the same, but the influence degree is different; the influences of camber angle and side slip angle on effective rolling radius and load radius are different; with the increase of tread wear, rolling radius and load radius decrease. Using the partial least square regression method, the regression equations about effective rolling radius and loaded radius are obtained. It is proved that the regression equations have high accuracy.

In order to ensure the safe use and healthy development of lithium-ion batteries, this paper elaborates the working mechanism, failure mechanism and failure mode of lithium-ion batteries. On this basis, the paper summarizes corresponding mitigation measures and indicates that development of computer failure analysis simulation technology, optimization of lithium ion batteries development plan and the development of solid lithium ion batteries are of great significance for the future development of lithium ion batteries.

A three-dimensional model of the fuel cell was established by COMSOL software, and the effects of three parameters (operating temperature, oxygen concentration and membrane thickness) on the performance of the fuel cell were studied. The results show that the fuel cell performance can be improved by increasing the operating temperature, and the suitable operating temperature range is 160~180 ℃. The output performance of the fuel cell is obviously improved by increasing the oxygen concentration, but the fuel cell performance is reduced by increasing the thickness of the film. The optimal membrane thickness is 20~ 60 µm.

In order to explore the impact of rims with different widths on handling stability, the tire contour scanning test, static stiffness test and six-component force test, subjective evaluation test and objective test of real vehicle handling and stability were carried out. The static characteristics of tires with different widths of rims were analyzed and compared through static test and research on the bench. The actual dynamic performance of tires was analyzed and compared through subjective and objective test of real vehicle handling and stability. The change trend of vehicle handling stability was explored when the same tire was mounted on the wheel hub with different width. Bench test results show that the wider the wheel hub is mounted, the higher the vehicle handling stability is. The subjective and objective test results of the real vehicle also confirm this conclusion.

To obtain the vehicle’s sprung mass and unsprung mass accurately, this research used the characteristics of the relative positions of the sprung mass and unsprung mass, with the height of the vehicle’s center of gravity with different body attitude as the reference, to derive the parameters required to calculate the unsprung mass, then calculate the corresponding unsprung mass based on the measured vehicle gravity center height and other parameters. Finally, the unsprung mass was weighed by disassembling a real vehicle. Test results show that the results of calculated unsprung mass are close to those of measured results, which proves that the research approach is feasible.