In order to find the cause of sunroof water leakage, this paper systematically studies three types of sunroof water leakage modes based on the bottom-mounted sunroof structure, including water leakage between the body and the roof seal strip, water leakage between the roof seal strip and the sunroof glass, water leakage over the guiding gutter. The result show that the sunroof water leakage are related to factors like the sunroof seal strip, the sunroof guiding gutter, the sunroof drain pipe, the body and the assembly. The sunroof water leakage can be effectively solved by improving the form of the roof seal strip, compression load performance, coordination with environmental components and joint quality, improving the layout, structure and water conductivity of the guiding gutter, improving the form, layout and displacement of the drainage pipe, improving the flanging size and surface quality of the body, optimizing the assembly environment, techniques and tooling positioning.

To address the issue of water leakage of automobile sunroofs, theoretical and experimental research on the inlet and drainage characteristics of automobile sunroofs are carried out. By simplifying the automobile sunroof drainage assembly system, the physical model of the sunroof drainage pipeline is constructed, and the pipeline design are modeled and derived, and the theoretical calculation formula of the maximum drainage capacity of the pipeline is obtained. A sunroof test bench is built to measure the influence of various parameters and pipeline parts on the drainage capacity of the drainage pipeline based on the theoretical analysis results, and the theoretical and test results are compared. The water inlet characteristics of the sunroof are experimentally studied, and the distribution characteristics of the water inlet and drainage of the sunroof under different vehicle conditions were analyzed. It is found that the water flow from the drainage pipe is distributed differently with the tilt angle of the vehicle, and the water drainage of the front side of the horizontal vehicle is higher than that of the rear. It is suggested that the slope of the vehicle should be considered in pipeline design to increase the design margin of the front water pipe.

To test the steering function of autonomous vehicles, a vehicle in the loop virtual simulation testing system design is designed. A rotating plate driven by a linear motor is added to the front axle drum group on the traditional drum/brake testing platform to achieve a maximum 10° steering function during vehicle driving. Combined with software simulation technology, dynamic braking force testing is carried out for the speed reduction of autonomous vehicles from 80 km/h to 20 km/h during steering operation, as well as braking friction force testing during the speed reduction to 0 km/h. The test results are analyzed and verified. The analysis results indicate that the testing system can achieve the expected braking ability of autonomous vehicles within a steering angle range of ±10°, and control the testing braking force accuracy within the range of ±5 N, whitch further verifies the effectiveness of the testing system.

In order to analyze the dynamic characteristics of electric vehicle body, a modal test is used to identify the modal parameters of an electric vehicle Body-In-White (BIW), and the test results are compared with traditional modal test results through the acceleration sensor. The results show that the maximum error of natural frequency of BIW obtained through 3D laser vibrometry is less than 1.3% and have a high consistency with the vibration mode obtained from the traditional modal test, which verifies the feasibility and accuracy of this test method.

In order to investigate the effects of Ionic Liquid (IL) additives on the tribological properties of the key pairs of internal combustion engine, nitriding cylinder liner and molybdenum spray piston ring under high-reinforcement conditions, the lubricating oil with 2% ionic liquid mass fraction is used to lubricate the pairs. By analyzing the surface morphology, composition and tribological chemical reaction products of the worn pairs, the paper investigates wear behavior and relates mechanism of pair under ionic liquid lubrication, and evaluates its influence on friction, wear and wear characteristics of pairs. The experimental results show that the ionic liquid additive can improve the tribological properties of nitriding cylinder liner and molybdenum injection piston ring pair. The ionic liquid has the best tribological properties at 180 ℃, which is related to the tribological chemical reaction of ionic liquid on the surface of cylinder liner and its products.

A correction estimation method considering sensor measurement bias was proposed to accurately estimate the lateral velocity of the tractor in autonomous semi-trailer vehicles. Based on the three-degree-of-freedom vehicle dynamics model, the measurement bias estimation model was established by expanding the front wheel angle, yaw rate bias, and lateral acceleration bias into the state variables. Taking into account the impact of dynamic model mismatch, a feedback correction mechanism based on the kinematic model was designed to adjust the estimation results of lateral velocity and yaw rate through feedback. The proposed method was implemented using the square-root cubature Kalman filter algorithm, and the observability of the estimator was analyzed. This method was verified on the joint simulation platform of TruckSim and MATLAB/Simulink. The results show that the proposed method not only eliminates the influence of measurement bias but also exhibits good convergence speed. Its performance is significantly better than estimation methods that do not consider measurement bias or only consider measurement bias.

In order to realize the design of pressure-casting parts for passenger car body, this paper, starting from the type and characteristics of pressure-casting process, analyzed the application of high pressure vacuum casting in large pressure-casting parts of passenger car body, then it analyzed the design principles and requirements of pressure-casting in terms of wall thickness, stiffener and pin layout for the application location of the common use parts of pressure-casting parts of body, including key joints, important beam systems, main reinforcement parts, shock absorber tower, A-pillar module, rear floor assembly, front cabin assembly, etc..

To analyze the influence of transient conditions on NO_x emission of heavy duty commercial vehicles, by classifying the transient operating conditions of heavy-duty commercial vehicles, the NO_x emission characteristics were tested under four typical operating conditions, including cold car start, stop and start while driving, driving through highway toll gates, and overtaking acceleration. The test results show that the transient condition will cause the NO_x emission to rise, and increase the consumption of urea solution, which is about 0.86~4 times of the steady condition.

In order to improve the high concurrency connectivity, degree of automation and efficiency of downloading upgrading, this article uses cloud-based microservice, automatic upgrade path strategy based on vehicle baseline, independent download channel and lightweight remote parameter correction to make lean design for Over-The-Air (OTA) system scheme. Function and performance test results of mass-produced vehicles show that this scheme satisfies the demand of concurrent use for vehicles with production capacity of one million unit, with upgrade stability nearly reaching 100%.

To improve the ergonomic comfort of electric vehicle charging ports, this paper analyzed the height, angle, position and other layout factors of the charging ports from the perspectives of ergonomics considering human body size, comfortable range of human activities, charging pile and charging gun parameters, and proposed a charging port layout scheme, which was verified and evaluated. In addition, the paper offered design proposals for charging operational visibility and operation space, which served as reference for charging ports of electric vehicle.