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2024 Volume 0 Issue 2  Published: 2024-02-24
  • Haoyuan Zhao , Jinlai Liu , Zihao Yu , Tao Wu , Tianjun Sun
    doi: 10.19620/j.cnki.1000-3703.20230766

    In view of the trigger control and storage-recording in the process of automatic driving data collection, this paper started from advanced automatic driving data acquisition technology and advanced automatic driving storage technology, firstly investigated the sensor configuration methods of China and foreign automakers, then reviewed the automobile Event Data Recorder (EDR) system, autonomous driving data recording system and general L3 level autonomous vehicle data acquisition and storage schemes, and concluded that the existing data acquisition and storage technology could generate low quality and high noise redundant data. Finally, based on Tesla’s Shadow Mode, the paper introduced a driving data acquisition and storage method for man-machine co-driving mode, and summarized the development trend of advanced autonomous driving data acquisition technology.

  • Hebo Yang , Xiaojun Zhang , Genggeng Luo , Jingzhe Xi
    doi: 10.19620/j.cnki.1000-3703.20230555

    To address the limitation that the traditional Automatic Emergency Braking(AEB) strategy based on Time To Collision (TTC) does not take into account the speed of the vehicle, this paper proposed a dynamic collision time threshold model that took into account the vehicle speed and an AEB control strategy based on dynamic collision time threshold was designed. In order to ensure the comfort and safety of the braking process, a two-stage braking strategy was determined and the deceleration rate was designed, using PI control to complete the vehicle deceleration control. The TTC thresholds for different vehicle speeds were determined through simulation and a dynamic crash time threshold model was established. Hardware-In-the-Loop (HIL) simulation results show that the AEB strategy designed in this paper improves the collision avoidance success rate by 47.6% compared with the traditional AEB strategy under the premise of ensuring comfort, thus has better comprehensive performance.

  • Lan Yang , Yipeng Yang , Songyan Liu , Zhiqiang Hu , Wei Yang
    doi: 10.19620/j.cnki.1000-3703.20230471

    To improve the collision avoidance performance of the Autonomous Emergency Braking (AEB) system in dangerous braking scenarios, this paper proposed an AEB control strategy considering the braking intention of the front vehicle and its test and evaluation method. A joint platform of PreScan, Simulink, and driving simulator was established to collect drivers’ braking operation data, classify the braking intention of the front car based on K-means clustering method, and use sliding time window to extract intention recognition model to train the dataset. The front car uses a double-layer hidden Markov model to identify the driver’s braking intention, while the main car calculates the critical safety distance threshold based on different braking intentions and performs collision avoidance control. A PreScan+Simulink virtual simulation and test environment was established, and AEB strategy comprehensive evaluation method was proposed based on Analytic Hierarchy Process (AHP). Four typical AEB control models were compared, which verified that the proposed method can timely trigger braking to avoid collisions in different braking scenarios, while reducing driving discomfort caused by premature braking.

  • Mafeng Tao , Jiankun Zhao , Naixing Yang , Yunxiao Zhuang , Gaofan Zhang
    doi: 10.19620/j.cnki.1000-3703.20230354

    In order to improve the prediction accuracy of State Of Charge (SOC) of power batteries, this paper proposed a method to improve the traditional ampere-hour intergral method to estimate the SOC of the lithium-ion battery based on a single particle Li diffusion model. The solver programs for estimating SOC with traditional and improved ampere-hour integration method and communication interface programs for battery data acquisition were written in software LabVIEW, which achieved the on-line monitoring of the battery SOC under different environmental temperatures and currents by the two methods. The results show that, under the above discharging conditions, the maximum estimation errors of the improved method and the traditional ampere-hour integral method are 1.11% and 1.89%, respectively. When the discharge current changes dramatically, the battery SOC estimated by the improved method fluctuates less than the traditional ampere-hour integral method.

  • Renhe Liu , Yihui Liu , Xinke Miao , Jun Deng , Liguang Li
    doi: 10.19620/j.cnki.1000-3703.20231077

    Based on the test platform of volume constant combustion bomb, the influence of geometrical parameters of the premixed single-orifice active pre-chamber on the ignition characteristics of the pre-chamber were investigated by the combustion visualization method. During the pressure constant combustion process in the early stage of flame development, the time from the start of ignition until the flame area reaches half of the visible window area of the combustion vessel is defined as the initial flame development time, which is used as a reference index to measure the ignition effect of the active pre-chamber under different geometrical parameters: under the test conditions of different orifice diameters (2.0~4.0 mm), different inner diameters of the pre-chamber channel (3.0~5.5 mm), and different open angles of the lower end (0°~75°), the maximal differences of initial flame development time are 9.3 ms, 6.8 ms, and 2.9 ms, respectively. Therefore, the effect of the three geometrical parameters on the ignition effect of the single-orifice active pre-chamber are, in descending order, the orifice diameter, the inner diameter of the pre-chamber channel and the opening angle of the lower end of the pre-chamber.

  • Xiuyong Shi , Haoyu Wang , Yifei Duan , Weiwei Qian
    doi: 10.19620/j.cnki.1000-3703.20230182

    To address combustion and emission issues in the lean combustion of gasoline direct injection (GDI) engine, ethanol-doped reformate gas was used to enhance the engine’s performance. The CONVERGE three-dimensional simulation technology was employed to explain the engine’s performance at a microscopic level. The results show that introducing ethanol-doped reformate gas can improve the distribution of equivalence ratio in the cylinder, promote the generation of H radicals and OH radicals, facilitating effective combustion. With an increase in the doping ratio of reforming gas, the distribution range and concentration of HO2 and H2O2 become wider and higher, and the stratification phenomenon in the combustion chamber becomes more pronounced. As the doping ratio of reforming gas increases to 20%, the peak values of in-cylinder soot generation mass and number density are reduced by 90% and 56.25%, respectively, effectively improving the soot emissions of GDI engines.

  • Hankui Lu , Zhigang Wang , Jinyin Li , Mengke Wang , Wei Li
    doi: 10.19620/j.cnki.1000-3703.20231066

    In order to improve the NVH performance of the timing housing of a gasoline engine specific for a range extender, several support bosses were added locally to the timing housing, which significantly improves the dynamic stiffness of the timing housing, and at the same time effectively reduces the vibration response and deformation per unit of excitation, so as to reduce the noise of the range extender assembly 1 m from the engine front-end side in the full-load acceleration condition by 4.0 dB(A), the linearity of the noise SPL and the acceleration of the vibration of the timing housing were significantly improved. The validation results show that improving the dynamic stiffness can effectively improve the noise radiation from the structural vibration of thin-walled parts.