In order to solve the problem of thermal diffusion of lithium-ion battery pack in use, this paper selects a certain type of square ternary lithium-ion battery, choosing glycol aqueous solution as the cooling medium to pour and cool the thermal runaway cell actively, so as to explore the temperature change law of the thermal runaway cell and its adjacent cells under different pouring amount, also the influences of water pump on the pouring speed are studied by stimulating a real vehicle environment. The experiment results show that the pouring amount and pouring flow rate of coolant are important variables affecting the occurrence of thermal diffusion. When the pouring amount is 1.5 L and the flow rate is 0.69 L/min, the maximum temperature of the thermal runaway cell is reduced from 713 ℃ to 556 ℃, effectively reducing the heat transfer from the thermal runaway cell to the adjacent cells, avoiding the thermal runaway of the adjacent cells, and preventing the occurrence of thermal diffusion in the battery pack.

In order to realize high-precision localization of Autonomous Valet Parking (AVP) system, this paper proposed a multi-sensor fusion localization algorithm based on vector map. In order to achieve long-term consistency of the localization effect, this paper employed visual semantic features to express the environment around the autonomous vehicle, and matched it with the vectorized map items to solve the absolute pose based on visual input. To achieve the above functions, this paper proposed a novel matching strategy to address the inconsistency of expression between observational data and vectorized map data. Meanwhile, by designing a reasonable error function and modelling the pose estimation problem as a nonlinear optimization problem, the method can achieve high-precision solution results. In addition, in order to improve the robustness of the localization results, this paper employed the Kalman filter based on the error state to fuse the results of the visual matching localization with the measured values of the IMU and wheel speedometer, and realized a tightly coupled modular localization method. The verification results based on real data show that the algorithm proposed in this paper is feasible in both theory and practice, and it can be seen from the comparison test with the mainstream methods that this method can achieve higher performance.

This article is aiming at the customers’ usage scenarios of a 4×2 light-duty express truck, and through on-site research to determine the driving routes for the customer data collection, road proportions, driving velocities, and load conditions. According to the force characteristics of parts and components and CAE simulation analysis of risk points in the suspensions, axles, steering and frame systems, where the corresponding sensors are arranged. By analyzing the frequency response of the vehicle on the customers’ typical road surface and the test site typical road surface, and according to the principle of damage equivalence, the number of cycles are solved for the test site characteristic pavement under the constraint conditions for the strain channels based on the relative damage spectrum correlation matrix, and then the test costs and test efficiency are considered combined with the review of the expert group to determine the test schemes. Finally, the test schemes are verified by the frequency domain damage histogram and rainflow counting results, also the driving specifications of the vehicle durability tests of the tests on-site are determined by the customers’ usage scenarios.

This paper calculated friction and wear through simulation based on AVL P&R piston ring dynamic calculation. The design of experiment method, response surface method and multi-objective genetic optimization algorithm were integrated on iSIGHT platform for optimal design of piston ring. The optimization results show that the height of upper barrel surface has a great influence on the oil consumption, the height of lower barrel surface and barrel surface offset have a great influence on the wear of piston ring and cylinder liner, the tangential elasticity has a great influence on the gas blow-by. Compared with initial piston ring, the wear of the optimal piston ring at 1 000 h reduces 43.2% from 11.1 μm to 6.3 μm.

Dynamic simulation model of IBC (Integrated Brake Control) of master cylinder, pedal simulator and other components was established based on AMESim, the pedal feel simulation analysis and the sensitivity analysis of key parameters under full functionality were carried out, and the influence of IBC’s simulator piston diameter, master cylinder spring stiffness, simulator spring stiffness and spring clearance and other component parameters on the pedal feel was analyzed.

This paper introduced the composition and working principle of the valve train and hydraulic lash adjuster of the engine, and used AMESim software to build the hydraulic lash adjuster model. Given the input signal of the cam speed, the working path of the cam lift section was consistent with the changing trend of the force, displacement, overcurrent and pressure in the high-pressure chamber of the hydraulic lash adjuster, thus verifying the correctness of the model. The paper also analyzed the influence of oil gas content, dead zone volume of high pressure chamber, oil temperature and oil grade on the working characteristics of hydraulic lash adjuster. The results show that the valve displacement decreases with the increase of oil gas content; the dead zone volume of high pressure chamber decreases, and the follow-up response of valve displacement improves; with the increase of oil temperature, the viscosity of oil decreases and the leakage increases, which leads to the decrease of valve displacement; with the increase of the high temperature kinematic viscosity of the engine oil, the corresponding kinematic viscosity grade will increase and the oil leakage will decrease.

In order to balance and optimize the fatigue durability and its own torsional stiffness of the torsion spring in the sunroof wind deflector, this paper analyzed the influence of the structural factors of the torsion spring on the fatigue durability by orthogonal test. The results show that the inner diameter of the torsion spring has the greatest influence on the fatigue durability, followed by the number of spiral coils and wire diameter, and the free angle of the torsion spring has little influence on the durability. The relationship between the number of durability cycles and the torsional stiffness of sunroof wind deflector torsion spring shows that there is no obvious relationship between the torsional stiffness of the torsional spring and fatigue durability. According to the influence of structural factors of torsion spring on fatigue durability, this paper proposed a balance optimization and improvement scheme for fatigue durability and torsional stiffness of sunroof wind deflector torsion spring, by increasing inner diameter of torsion spring, increasing the number of spiral coils and wire diameter. Bench durability and downward pressure test results show that the improved scheme can meet the fatigue durability requirements while increasing tension of wind deflector screen.