Thermodynamic Performance Of Valve-controlled Damping Adjustable Shock Abosorber

As a damping force adaptive shock absorber,valve-controlled adjustable shock absorber could gain its optimal driving stability and riding comfort for different road vibrations.So it has a large potential application in automobile market.So this thesis focused on the thermodynamics performance of valve-controlled adjustable shock absorber,the main work and achievements in this thesis included:(1)Based on the theory of hydromechanics and elasticity mechanics,the throttling characteristics of the superposition valves in three conditions,namely,pre-open,opened and maximum opened,were established correspondingly.The effects of valves' number,outer radius,maximum deformation and fixed throttle diameter on its throttling characteristic were researched in the end.Results indicated that: pressure drop grown up with the increasing of valves' number,outer radius of valves caused a raise of pressure drop after opened valve,maximum deformation decreased the pressure drop after maximum opened,and addition of fixed throttle diameter made a degradation of pressure drop during each working conditions.(2)The thermodynamic balance model of this shock absorber was established on the basis of damping heating and heat transfer.The effects of vibration velocity,outer diameter,thickness and length of reservoir cylinder,and wind velocity on its thermal performance have been considered.Specifically,temperature after thermal balance will grow up with the increase of vibration velocity and length of reservoir cylinder's thickness,and degrade with the increase of outer diameter and length of reservoir cylinder,and wind velocity.The higher the balance temperature,the shorter time is required to arrive thermal balance.(3)A test bench of electro-hydraulic servo control system with oil temperature acquisition module was set up,and the temperature rising curves under 4 different vibration velocities were obtained,conclusions showed that: comparing experimental values with simulation,the difference of oil temperature after thermal equilibrium at the same vabration velocity were less than 2?,but experimental values delayed simulation,this were mainly caused by accumulative error of stepped iteration in simulation and mechanical hysteresis in experiments.(4)The indicator diagram and its' attenuation curve at 4 vibration velocities was measured experimentally,the maximum difference between experimental values and simulation was 3.44% and occurred at the speed of 0.052m/s,which was mainly caused by mechanical friction at low speed.When at the speed of 0.524m/s,the oil temperature growed up by 58? approximately,and damping work rate decreased by 25.64%.However,the shock absorber could still provide a damping work of 281 J per cycle,and the indicator diagrams were smooth and full,without any obvious distortion.Those indicated that this valve-controlled adjustable shock absorber has a good damping characteristics after thermal balance.