Research On Energy Recovery System In The Braking Process Of Hydraulic Cylinder

In engineering machinery,such as excavators,loaders,often driven by hydraulic cylinder,the hydraulic cylinder starting and braking frequently.In order to prevent shock in the process of braking,the hydraulic cylinder usually adopts hydraulic brake valve for braking.When braking,the kinetic energy of the system will be in form of heat dissipation on the throttle opening,resulting in the hydraulic oil temperature,and braking performance of the system.Especially a greater influence on frequently braking system.At the same time,using hydraulic brake valve will consume large amounts of energy,and is not conducive to energy conservation.In order to make the components smoothly braking,minimizing impact pressure in the buffer,and recycling the braking energy,the domestic and foreign scholars have done a lot of research.Mainly from improving the engine fuel efficiency,enhancing the structure of the hydraulic system control strategy and optimizing the engine load-power matching,but the process of braking energy loss problem still remained.For frequently starting and braking of the overloading brake impact and energy loss problems of hydraulic system,this paper sums up the existing brake systems,combining with the load sensitive structure characteristics and working principle of two-way brake circuit,put forward a system that an accumulator as the energy storage component,accumulator pressure control variable displacement pump of the hydraulictransformer,to complete smooth braking and energy recovery.Make a schematic diagram,and combine with the mathematical models to expounds the working principle and control method of the system.Using this no throttling loss control method effectively reduces the impact pressure and energy loss.In the braking characteristics,under the premise of both energy recovery efficiency,made a basic introduction to main components that brake circuits,cut-off valve,accumulator,hydraulic transformer.Analyzed of its working principle and mathematical models,and selection and parameter matching,designed the cut-off valve structure,drew the structure schematic diagram,Finally through the hydraulic transformer,accumulator,cut-off valve to cooperate with each other,to meet the requirements of the system.Under the condition of a given condition,simulated the braking energy recovery system in the AMESim software,set up the system parameters,get the simulation curve of hydraulic cylinder brake chamber and accumulator pressure,the variable pump displacement change and accumulator volume.The results showed that the system can achieve smooth braking rapidly and recycle most of the kinetic energy.This paper also discussed the condition of braking characteristics and energy recovery efficiency of system under the different quality of load and velocity,the research results showed that the system has strong ability to adapt to different conditions.Compared with load sensitive braking system,fully proved that the new system’s superiority in braking and energy recovery.Pointed out the factors which affect the energy loss and energy recovery efficiency of the system,mainly including the mechanical friction loss,leakage loss,viscous damping loss and loss in the process of control,etc.On the analysis and calculation,get the total efficiency of energy recovery system reached63.24%.Through detailed analysis of the simulation system model,studied the the hydraulic transformer displacement,rotational inertia of speed reducer,the initial pressure and volume of the accumulator,the parameters of the cut-offvalve set the specific influenced to the braking energy recovery system,and finally provided theory basis to determinate and optimize the hydraulic elements parameter determination and optimization.