Pan Asia Technical Automotive Center (China)

Engine misfire is an accidental failure mode in internal combustion vehicles that can lead to the malfunction of power transmission system components. However, previous studies on engine misfire have generally focused on the engine rather than the drivetrain. In this study, we established a simulation model of a hybrid drive system with multiple degrees of freedom to investigate the torsional shock characteristics of the engine under normal and engine misfire conditions. Factors such as the torsional stiffness, gear‐pair meshing stiffness, and moments of inertia for the damper, generator, and drive motor were considered. The dual‐mass flywheel (DMF) was subsequently applied in the drivetrain model, and its stiffness parameters were varied to optimize their effects on the torsional shock experienced by the power transmission system. According to the results, the first‐ and second‐stage stiffnesses of the DMF were set as 5.1 and 15.0 Nm/deg, respectively. Finally, the performance of the designed DMF damper was evaluated through simulations and physical tests of the drivetrain. The engine at full load under normal and engine misfire conditions as well as under a steady‐state load when generating power at the engine output was investigated. The simulation results indicated that the torsional shock on the power transmission system satisfied the design limit of 500 Nm with an angular acceleration below 500 rad/s2. The errors between the simulated and measured peak impact torques and resonance speeds under the misfire condition were approximately 15% and 5%, respectively.

A vehicle seat adjustment system based on body image recognition is designed. The system uses body image recognition algorithms to calculate the physique parameters of passengers, and automatically adjusts the vehicle seat position. Through on-site testing, the matching rate between the automatically adjusted vehicle seat position and passenger body shape reaches 98.1%, which can effectively improve the convenience and comfort of the vehicle.

Abstract The hybrid metal/GFRP laminate is a kind of typical hybrid structure consisting of thin metal sheets and glass fiber reinforced plastic laminates, which combines the benefits of low cost, high strength, excellent impact resistance, and good corrosion resistance. In this work, a semi‐experimental method based on a nondestructive test and the analytic solution of the thin plate's deflection for the flexural and sinking stiffnesses identification of hybrid metal/GFRP laminates was proposed and validated by corresponding numerical simulations. Then, in total 17 different specimens (including metal, GFRP and hybrid metal/GFRP) were prepared and tested by the proposed semi‐experimental method to investigate their flexural and sinking stiffness performances in multiple perspectives (including stiffness per unit mass/volume/price/surface density). The analytic solutions show that the flexural and sinking stiffnesses are proportional to macro equivalent moduli of laminate specimens and proportional to the third power of thicknesses of specimens. The test results show that the stiffnesses per unit mass/density of the 7‐ply GFRP laminate can be comparable to those of the variable‐thickness rolled blank (VRB) made of steels, but the stiffnesses per volume/price of the 7‐ply GFRP laminate are only one fifth to one quarter of those of VRB. It is also found that though the hybrid metal/GFRP laminate with the combination sequence of aluminum plate/5‐ply GFRP/aluminum plate has the lowest GFRP layers' volume fraction, but has the best performances of stiffnesses per unit mass/density. Besides, the VRB part can significantly improve the stiffnesses per unit volume of hybrid metal/GFRP laminates.

ABSTRACT As a swarm-based metaheuristic algorithm, the crow search algorithm (CSA) has attracted a lot of attention owing to its simplicity and flexibility. However, CSA tends to have low efficiency. To improve the optimization efficiency, this article proposes a modified version of CSA based on group strategy with an adaptive mechanism (GCSA). On this basis, crows are divided into multiple competing groups, and are assigned different roles and statuses. Then, the group strategy including different search modes is implemented to increase the solution diversity and search efficiency. Moreover, benefiting from the adaptive mechanism, the search range of crows changes in different stages to balance exploration and exploitation capabilities. To evaluate the performance of the proposed algorithm, 35 benchmark test functions (including 10 CEC2020 functions) and three engineering design problems are solved by GCSA and 11 other algorithms. The results prove that GCSA generally provides more competitive results than other metaheuristic algorithms.

Abstract Lithium‐sulfur (Li−S) batteries have great potential for the development of next‐generation high‐energy‐density secondary batteries owing to their high theoretical energy density, active material (sulfur) environmental friendliness, and low cost. However, their application is still impeded by the inherent sluggish kinetics and solubility of intermediate products of the sulfur cathode. Interface design is an important direction to address challenges in the development of Li−S batteries. The modification of the separator has been shown to effectively suppress the shuttling effect of physical hindrance or chemical bonding without affecting the utilization of active materials. This review encompasses the application of nanostructured transition metal oxides (TMOs), transition metal sulfides (TMSs), transition metal nitrides (TMNs), transition metal phosphides (TMPs), such as incorporating functional separators beyond the approach for preparing novel cathodes, and discusses their composites in a new multifunctional barrier layer for Li−S batteries. The objective properties of various metal compounds and the effect of the shuttle effect in particular on the electrochemical performance in Li−S batteries are highlighted, and give an outlook on the promising approaches for the construction of reliable Li−S batteries.

In this study, Lyapunov stability theory was used to systematically investigate the stability of centrifugal pendulum vibration absorber (CPVA) in terms of the shape of the absorber path, mistuning levels, damping coefficient, number of absorbers, and force of gravity. Our approach improved upon previous studies by introducing a gravity term, optimising the calculation method, and using a function diagram to represent the asymptotically stable region to produce more accurate results. Our finding that the influence of gravity on the stability of the CPVA system is reflected in the change of the tuning order prompted us to define new terminology—’gravity mistuning factor ([Formula: see text])’ and ‘zone yielding to gravity ([Formula: see text])’—to intuitively reflect the influence of gravity. Comparison of the results obtained from numerical simulation based on a fully nonlinear equation of motion with analytical results revealed nonlinear dynamic characteristics such as bifurcation to asynchrony response, nonlinear jump, and beat phenomena. The approach and results of this study are more practical in settings in which gravity plays an important role, including vehicle engine idling, low-speed locomotive or marine engines, and drum washing machines.

Motion planning is an important and complex research content in automatic driving system. This paper proposes a motion planning method in lane change scenario, which decouples the motion planning into two parts: longitudinal and lateral planning. This method takes the leading vehicle of each lane change gap as the following control vehicle, obtains the longitudinal trajectory of each gap by LQR algorism. Then the most appropriate lane change gap is selected through a certain strategy, which is developed on driving comfort and timeliness. After the gap selection, the host vehicle follows the leading vehicle of the selected gap to adjust its speed and position to meet the lane change condition. The lateral planning is initialized when the condition is met. The whole algorithm has a small amount of calculation and is convenient for practical engineering application. Finally, the validity and practicability of this method are verified by a real vehicle test.