For the issue of driving style identification, this paper proposes a method based on subjective and objective fusion. Firstly, the subjective style scale is developed and transformed into subjective factors. Secondly, a data acquisition system is implemented to gather the natural driving data and the basic behavior scenarios of car following and lane changing are mined. Thirdly, the fusion of subjective and objective identification system of driving style is constructed by extracting the key behavioral characteristics and subjective factors. Based on Principal Component Analysis (PCA) and K-means methods, the sample set is processed and the clustering results are verified. Finally, specific characteristics with physical significance are introduced to identify radical, moderate and conservative driving styles. The results reveal a strong correlation between the distribution of subjective style factors and objective behavioral characteristics, and the fusion method can be used to identify driving style effectively.

The rainwater pollution on vehicle side window affects driver’s safety critically, it is necessary to study this kind of water management situations. By improving the key parameters of windshield water bar, and in combination of vehicle climate wind tunnel test results of different windshield water bars of a SUV, this article quantiataively analyzes water pollution area of the front side window and the exterior rear view mirror area by image processing technology, and proposes an evaluation method considering the lateral and rearview field comprehensively. It is found that increasing the height of the windshield water bar and the water storage area can reduce the water flow to the side window and weaken the water pollution of the side window. Finally, a water bar scheme for the front wind window with better visual field and engineering feasibility is obtained.

To address the issue of deterioration of soot caused by EGR technology, a shunt centrifugal oil filter is introduced based on the principle of centrifugal sedimentation, and its structure principle, critical characteristic and influencing factors are systematically reviewed. A magneto-electric test system based on speed characteristics is developed, and the key points of adaptive design of centrifugal oil filter are explored. The soot-removal effects of the centrifugal oil filter are analyzed from the aspects of physical and chemical testing of oil products, plugging life of filter element and driving test. The results show that the soot-filtration effect of centrifugal oil filter is more obvious for EGR models, but slightly redundant for SCR models. The paper analyzes the influence of soot on oil viscosity and the benefit mathematical model of centrifugal rotor filter on fuel consumption builds based on the relationship between oil viscosity on fuel economy.

In order to solve the problem of difficulty in Computer Aided Engineering (CAE) evaluation of forming failure of small fillet feature line, for a door outer panel with such feature, AutoForm was used to control the material inflow by adjusting the drawbead, and four kinds of door outer panel models with different forming states are obtained. Meanwhile, the forming condition and practical stamping condition with and without thickness stress are analyzed respectively. The results show that the forming limit of small size fillet feature line is reduced due to the influence of thickness stress, and uneven plastic deformation will occur in further forming, so the traditional formability CAE evaluation method is not suitable for small size fillet feature lines. Finally, a CAE method for evaluating the formability of small fillet feature lines combined with slippage is proposed, that is, when the slippage is less than 5mm and the thickness reduction rate and maximum nonlinear failure value meet the requirements, it can be considered that there is no formability risk of small fillet feature lines.

The A/B system upgrading technology is proposed to solve the problem that the System on Chip (SoC) Electronic Control Unit (ECU) cannot roll back the software when the Over-The-Air (OTA) upgrading failed. The technology downloads the program to the backup slot by reading the MISC of ECU slot information, and starts the installation by designing the priority level of the A/B system to select the active partition or rolls back the software in case of upgrading failed. At the same time, the differential graded technology of A/B system is designed. The ECU using this technology can perform software rollback when upgrading fails,and the feasibility, effectiveness and stability of rolling back software technology are verified by building a test environment.

To analyze the performance of the battery direct cooling and heating management system coupled with passenger cabin air conditioning, a power battery thermal management system model is established based on AMESim software. The charging time of typical liquid cooling and direct cooling and heating management systems under high-temperature fast charging conditions is compared. The results show that under the same fast charging MAP, the charging time of the direct cooling system is shortened by 7.6% compared with the liquid cooling system. The passenger cabin air conditioning and battery thermal management system is further coupled, and a thermal management control strategy is designed with the goal of controlling the temperature of the passenger cabin and the maximum temperature of the battery cells. Results show that compared with the uncoupled system, the maximum temperature difference on the top of the battery increases by 2.9 ℃ when using the coupled system, but the charging time is shortened by 4.9%.

In order to solve the problem of target detection failure of millimeter wave radar due to radar occlusion under complex road conditions, this paper proposes a radar occlusion detection method based on spectral estimation. Multi-channel signal accumulation is used to solve the two-dimensional spectrum of echo, adaptive CFAR detection algorithm is used to eliminate the radar target, and Spectrum estimation is used to solve the echo background power. The occlusion detection is accomplished by counting the energy distribution characteristics of the echo in a certain time interval. The experimental results show that the proposed method can achieve the radar occlusion state estimation with an accuracy of over 70% in 10 s and over 90% in 100 s.

In order to realize the development of vehicle functional safety based on Service Oriented Architecture (SOA), the forward development process for automotive functional safety based on SOA is established combining with the ISO 26262 standard. The functional safety design methods of function-based concept phase and architecture-based system development are proposed. On the one hand, for the concept development phase, the functional safety requirements are derived based on the product capabilities, and the function safety class of product capabilities is defined. On the other hand, for the system development phase, the technical safety requirements are derived and distributed based on the software component architecture and physical deployment.

Under high-frequency variable loads, EV electrical system is prone to causing bus voltage oscillations and instability. A small-signal model of the vehicle’s electrical system has been established, obtaining the output impedance of the system source-transformer and the input impedance of the motor load. Based on the traditional impedance ratio criterion and combined with the system’s stability margin, the stability determination principle of the vehicle’s electrical system has been derived. By using a Bode diagram for predicting system instability, research is conducted to explore the instability boundary of pure electric vehicle under high-speed conditions. The simulation verification results show that the vehicle’s maximum speed shall not exceed 188 km/h, and torque variation of hub motor will affect vehicle stability, the torque mutation of single hub motor shall not exceed 220 N·m, which is basically consistent with theoretical analysis results. The results prove that this stability determination principle can predict instability boundary of vehicle electrical system to some extent.

In addressing the issues of suboptimal solutions and poor exploration performance in narrow passages of intelligent car path planning using the Rapidly-exploring Random Tree-Connect (RRT-Connect) algorithm, this paper improves the RRT-Connect algorithm in expansion strategy and path smoothing based on an analysis of the basic principle of the RRT-Connect algorithm. Firstly, in terms of expansion strategy, a probability bias method is introduced to screen random points, and an expansion method based on artificial potential fields is used to shorten paths and reduce computation time. Secondly, regarding path smoothing, a third-order B-spline curve is introduced to optimize the path and generate a smooth path, ensuring that the path meet the dynamic characteristics of intelligent cars. Finally, the superiority of the improved RRT-Connect algorithm is demonstrated through comparative simulation. The results show that in environments with simple obstacles, complex obstacles and narrow paths, the average time and path length of the improved RRT-Connect algorithm are superior to those of the traditional RRT-Connect algorithm.