No abstract

CDC (Continuous Damping Control) shock absorber is the typical representative of the stepless valve-controlled type, which has the advantages of low cost and stable performance. Based on the throttling characteristics of the CDC valve, the damping force mathematical model of the CDC shock absorber is established. Through simulation analysis, the indicator characteristics and speed characteristics of the CDC shock absorber under different input currents and speeds are obtained. A CDC shock absorber testbed is built to study damping characteristics, and the results are compared with the simulation results. The results show that the indicator diagram obtained by simulation and experiment is smooth without distortion, and the speed characteristic diagram is smooth without a large mutation point. The experimental values of damping force are slightly larger than the simulation values. The relative error between the simulation data and the experimental data is basically less than 10% and the model has high accuracy. When the input current is the same, the damping force increases with the increase of piston rod speed. When the speed of the piston rod is the same, the damping force of the rebound and compression stroke decreases with the increase of input current.

Valve-controlled damping adjustable damper has the characteristics of simple structure and adjustable damping, and it has always been a hot research topic. This paper establishes a mathematical model of damping characteristics of the valve-controlled damping adjustable damper and designs the experiment of the damping characteristics of the compression stroke and the recovery stroke. Through simulation and experiment, the accuracy of the mathematical model is verified, and the damping contribution rate of different key parameters under different excitation speeds is analyzed. The results show that the mathematical model of the damping characteristics can well describe the working state of the damper. The damping contribution rate of key parameters under different excitation speeds is obtained. The damping contribution of the constant through-hole diameter decreases gradually after the valve is opened for the first time. With the increase of the excitation speed, the valve plate equivalent thickness and the valve plate maximum limit clearance of the check valve gradually play a major role in the damping contribution rate. The research results can screen out the key parameters, improve the development efficiency of the damper, and provide guidance for the damper design and optimization.

The torque to volume ratio and time response characteristics of the clutch during vehicle travel power generation are important issues that affect the quality and efficiency of power generation. In this work, a magnetorheological clutch was established based on the magnetorheological effect and analyzed its magnetic field strength, maximum output torque, time response characteristics, and temperature rise characteristics in driving power generation. The results indicate that the maximum torque of 77.05 N·m is only 3.68% less than the designed value. MR clutches have a better torque to volume ratio for the same volume. The MR clutch can realize millisecond regulation of power output characteristics, the response time of the torque loading section is about 345 ms, while the response time of the torque withdrawal section is about 680 ms. The MR clutch has good heat dissipation performance with an external water-cooling device. Using an MR clutch as a governor for traveling vehicle power generation, the time-varying engine speed is converted to a constant speed by continuously adjusting the excitation current, which can provide more efficient power generation.

A compound-driven magnetorheological (MR) valve is designed to cope with the low reliability and high energy consumption of traditional MR valves. The operating magnetic field of the valve is applied by both the excitation coil and ring magnet, maintaining excellent pressure drop performance even at zero current. To analyze the performance and obtain the variation law of the magnetic flux density and pressure drop, a pressure drop mathematical model and a magnetic field simulation model are established. The key parameters of the MR valve are also optimized using non-dominated sorting genetic algorithms-II (NSGA-II). A dynamic performance test system is built, and the influence of the load on the pressure drop and hysteresis characteristics of the MR valve is studied. The results show that the optimized pressure drop and adjustable coefficient are improved by 4.7 % and 8.6 % respectively. The pressure drop grows nonlinearly with the electric current and reaches saturation at a current of 1.5 A, and a pressure drop of 1485 kPa is still generated at zero current. The output damping force of the compound-driven MR valve-controlled damper can be continuously adjustable, indicating that the dynamic performance of the damper can be controlled by adjusting the input current.