油气状态对车辆油气悬挂特性影响建模分析

Influence Analysis and Modeling of Oil-gas State on Characteristics of Vehicle Hydro-pneumatic Suspension

油气悬挂内部的油液和气体并非绝对的理想状态,而是随着压力变化发生溶解或析出,对悬挂输出特性影响较大。基于此,提出真实气体状态方程,建立考虑气体溶解与析出特性的油气悬挂分析模型。运用Simulink仿真分析模型和油气悬挂性能分析试验台,选取冲击载荷、周期激励及正弦小振幅扫频激励等工况,分析油气悬挂的簧上质量位移和压力响应特性。结果表明:冲击载荷作用1.5 s左右达到平衡状态,试验和仿真平衡位置误差小于3%;周期性激励作用下,运动位移和气体压力的仿真结果与试验测试数据一致,位移最大误差范围在1 mm内,气体压力响应误差范围在0.06 MPa内。扫频激励作用下,系统性能满足要求,试验结果和仿真分析变化趋势基本一致。考虑气体溶解与析出特性的数学模型对油气悬挂设计具有一定的指导意义。

The oil and gas inside the hydro-pneumatic suspension are not absolutely ideal state,but dissolve or precipitate with the change of pressure,which has a great influence on the output characteristics of the suspension.Based on the real gas equation of state and considering the characteristics of gas dissolution and precipitation,a hydro pneumatic suspension analysis model is proposed.Simulink simulation analysis model and hydro-pneumatic suspension performance analysis test-bed are established.The impact load,periodic excitation and sinusoidal small amplitude sweep excitation conditions are selected to analyze the displacement of the suspension spring mass and pressure response.The results show that:the impact load reaches equilibrium state about 1.5 s,and the error of equilibrium position between test and simulation is less than 3%.Under periodic excitation,the simulation results of motion displacement and gas pressure are consistent with the test data,the maximum error range of displacement is within 1 mm,and the error range of gas pressure response is within 0.06 MPa.The results show that the performance of the system meets the requirements under the frequency sweep excitation,and the change trend of the test results is basically consistent with that of the simulation analysis.The mathematical model considering the characteristics of gas dissolution and precipitation has a certain guiding significance for the design of hydro-pneumatic suspension.