To obtain engine braking power accurately, this paper proposed a method of engine braking road test based on the momentum conservation law. A vehicle braking power equation based on speed and gear was built to provide a warning of downhill shifts and AT gear selection. Braking power test result obtained with the proposed test method was compared with dynamometer test result, with a difference range of -2.7%~3.4%, demonstrating accuracy and effectiveness of this method.

In order to deeply explore Yolo target detection algorithm and its development direction in the field of autonomous driving, this paper reviewed the research progress and main accomplishments of YOLO algorithms (YOLOv1~YOLOv8), analyzed and expounded its application in relevant detection tasks including vehicles, lane lines, pedestrians and traffic signs in the field of autonomous driving. Combining the characteristics of Yolo series algorithms, the paper analyzed and summarized the future improvement ideas and research trends of Yolo algorithm.

In order to solve the problem of abnormal vibration and noise generated by the Electric Power Steering (EPS) system of passenger cars under bumpy road conditions, this paper proposed a new damped block structure by adding an O-ring at the EPS block position. By analyzing the influence of O-ring static compression and stiffness on damping performance, the optimal compression of O-ring was confirmed to be 0.5 mm. The EPS endurance test was carried out with the road spectrum of the vehicle. The results show that the performance of vibration noise deteriorates after a long mileage with increase of EPS block gap. Subsequently, the bench noise test of the EPS with traditional block and new block under different block gap was conducted. The results show that the vibration acceleration of the EPS with the new damped block structure is reduced by a maximum of 9 m/s² and 6.2 m/s² at the bushing end and block end, respectively, proving that the new damped block structure has a significant optimization effect on the vibration noise of the EPS system under bumpy road conditions.

This paper took noise generated from air suspension modulation of a vehicle as research object. Through transmission path study, the paper determined that the noise was mainly generated through the body structure excited by the air compressor. Through theoretical analysis, it was found that the main factors affecting air suspension noise transmission were the air compressor system modal frequency and Noise Transfer Function (NTF) from the body attaching point to the vehicle interior. The paper proposed optimization schemes including power supply wiring harness wrapping material optimization, bracket vibration isolation and bracket reinforcement + NTF. The results show that bracket vibration isolation is the best scheme, after implementation, the 1^st order noise order of air compressor was reduced by 4 dB, 2^nd order noise was reduced by 14 dB, and the sound quality in the vehicle was significantly improved.

For the problem that it is difficult to determine the influence of the opening size of automobile electric sunshade on the operating performance, this paper, by analyzing the structure of the electric sunshade and the basic motion parts in detail in the process of unrolling and winding of the sunshade, obtained the relationship between the stress state and the position of the sunshade in the motion process, thus established a mathematical expression of the system resistance and its opening size of the sunshade. The calculation data of the design sunshade is compared with the measurement data of the real sample, which show that, the calculated data of the sunshade model is basically consistent with the measured data of the real sample, verifying the effectiveness of the mathematical model of the sunshade system resistance.

To address the issue of the increase of unsprung mass and suspension parameters needing adjustment after upgrading a central motor electric vehicle to a wheel hub motor car, a half-car passive suspension model was established in MATLAB/Simulink. The spring stiffness and damping coefficients of the front and rear suspensions were taken as independent variables, while the root mean square values of the vehicle’s center of gravity acceleration, pitch angle acceleration, suspension deflection, and tire dynamic load were considered as optimization objectives. The grey wolf optimization algorithm was employed to search for the optimal stiffness and damping parameters. The simulation results show that after optimization, the handling stability of the suspension remains within a reasonable range, while the comfort level is improved by 12.73%.

To shorten the development cycle of Dedicated Hybrid Transmission (DHT), the Hardware In the Loop (HIL) simulation platform was built to perform the virtual calibration of the electric control parameters for DHT. The obtained calibration dataset was compared with the conventional calibration data of real vehicle. The results show that the calibration data obtained from virtual calibration method is similar to that obtained from conventional method, can shorten vehicle development cycle effectively.

Based on a 200 kW peak power three-stack common-rail Proton Exchange Membrane Fuel Cell (PEMFC), the steady Computational Fluid Dynamics (CFD) iterative calculation between the single pulse valve ejector and the multi-stack common-rail pulse valve ejector under and hydrogen supply system was carried out by Fluent software, and the ejector scheme was determined. Then the reliability of the design and simulation was verified by the ejector bench test. The influence factors of pulse valve ejector were simulated and analyzed, from which we can know that with the same pressure variation, the injection pressure of secondary flow has the greatest influence on the ejection coefficient, followed by the inlet pressure, and the injection pressure has the least influence. Meanwhile, nitrogen content has great influence on the ejection coefficient. Finally, the transient simulation analysis of the pulse valve ejector was carried out. The results show that, compared with the steady state results, the ejection coefficient calculated under transient state has a large margin, so it can further cover the low power condition. Keeping the duty cycle unchanged and increasing injection frequency are beneficial to the improvement of ejection coefficient.

In the semantics mapping construction of Simultaneous Localization And Mapping (SLAM) algorithm, to solve the problem that the semantics information extracted by using deep learning technology contains noise, this paper proposes a representation method for semantic observation by probabilistic grid. The influence of noise is reduced by grid matching and probability updating, in this way, a clear map can be incrementally constructed without auxiliary means like features matching. The effectiveness of the proposed method is verified by experiments in which clear zebra crossings and lane lines are contained in the constructed map.

In order to recognize driving fatigue, this paper proposed a fatigue detection method based on wavelet characteristics and Long Short-Term Memory (LSTM) neural network classifier. Two kinds of EEG signals (non-fatigue and driving fatigue) were collected in the real driving environment. The EEG signals were decomposed by wavelet, and the statistical values, energy values and relative energy values of four wavelet coefficients were calculated as the characteristic data, which were used for classification training and test of the LSTM neural network. The results of experiment show that the classification performance of LSTM neural network gradually improves with the increase of the number of channels involved in constructing characteristic data. Especially, in the scheme of 14 channels, the average classification accuracy is about 96.1%.