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 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.

To solve the problem of abnormal friction noise of sunroof sealing strip on bumpy road, the frequency response analysis of vehicle input load signal simulating real road conditions was carried out. Firstly, an abnormal sound Evaluation Line (E-Line) was defined between the car body and the sunroof. Because the seal and the sunroof produced to-and-fro movement in Z direction and Y direction, the maximum relative displacement in Y direction and Z direction in each E-Line was obtained by calculation. Secondly, stick-slip test between sealing strip and PU surface was carried out on friction test bench to obtain the minimum abnormal noise displacement of seal. Finally, the results of simulation and test were compared to judge whether there was abnormal noise risk. The results show that by controlling the relative displacement between sunroof and vehicle body and the minimum abnormal noise displacement of seal, the risk of abnormal friction noise of seal can be reduced in the vehicle development stage.

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.

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 solve the defects of decreased vehicle comfort of pure electric passenger car when air conditioning system is turned on to cool the power battery, this paper, combining actual development projects, determined the typical travel chain of electric vehicle according to the sales target area of developed vehicle, and formulated the annual calendar driving conditions of electric vehicle according to the travel chain. The vehicle bench environment simulation test was carried out according to the annual calendar driving conditions, and the statistical analysis of the battery temperature distribution in three states of the vehicle in driving, charging and storage within one year was completed according to the test results. The battery cycle life evaluation was completed, and the influence of each operating condition of the vehicle on the battery life attenuation was decomposed, and the battery cooling system control strategy was optimized. The results indicate that, the proportion of cooling system engaged in the battery cooling process decreases greatly, air conditioning comfort improves obviously.

In order to explore an effective test method for the thermal management performance of 48 V power battery, the thermal management performance of 48 V battery was studied and tested on a vehicle equipped with P0 mild hybrid system under different test conditions, ambient temperature and air conditioning mode. The results show that the World Light Vehicle Test Cycle (WLTC) is the most suitable to verify the thermal management performance of the 48 V battery. The high temperature performance of 48 V battery can be effectively verified by continuously performing 5 WLTC test cycles at a high temperature of 30~50 ℃, the low temperature performance of 48 V battery can be effectively verified by continuously performing 8 WLTC test cycles at low temperature of -25 ℃. The internal and external circulation mode of the air conditioner impacts the thermal balance temperature of the 48 V battery remarkably.

In this paper, the applicability of DIN 75220 Aging Automobile Components in Solar Simulation Units to the typical dry, humid and hot climate environment in China was studied by comparing and analyzing the light, temperature and humidity conditions and vehicle test results in the environmental chamber and atmospheric exposure tests. The results show that the nighttime temperature of the simulated dry hot climate environmental cycle conditions in DIN 75220 standard is higher than the winter nighttime low temperature of domestic dry hot climate environment, and the nighttime temperature and humidity in the simulated humid hot climate environmental cycle test conditions is lower than the nighttime temperature and humidity in the domestic humid hot climate environment. The cycle test of DIN 75220 for 600 h is equivalent to 6~7 months of dry hot atmospheric exposure test and equivalent to 8~9 months of humid & hot atmospheric exposure test, which can reflect about 69% of the test problems occurred in 6~9 months of atmospheric exposure test.

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.

This article studied the ultimate strength bench test method of suspension system of passenger vehicle, it firstly compared and analyzed the characteristics of strength test of vehicle, suspension system and parts, and then introduced the test method of suspension ultimate strength test from the working condition and selection of the definition, the loading form of the load, test equipment and test bench design, test data acquisition and processing, and proposed the way to the evaluate test results. Finally, the paper illustrated the application of the combination of suspension system and component strength bench test with an actual case, and explained the role of suspension strength bench test in product development.