Research On Potential Energy Recovery Scheme Of Asymmetric Variable Axial Piston Pump With Motor Driven

With the vigorous development of infrastructure in the country,the use of construction machinery will reach a new height,but there are still some problems such as high energy consumption,serious environmental pollution and so on.Many construction machinery operating mechanism have the situation of feed backing energy to system,such as the potential energy of excavator arm when lowering and the kinetic energy of the rotary mechanism when braking.When the frequency of operation is high,the mass or moment of inertia is large,a large amount of potential and kinetic energy of the operating mechanism is usually consumed on the orifice of a hydraulic valve,which not only wastes energy,but also causes heating of system and service life decreasing of components.It is an effective measure for energy saving and consumption reduction of construction machinery to recover potential energy and kinetic energy for high-frequency operation mechanisms with large mass and moment of inertia.Therefore,in order to solve this problem,domestic and foreign scholars have proposed various hydraulic systems for energy recovery programs.In many cases,the hydraulic system boosts the working device by output energy.In the descent process,the waste of potential energy is usually reduced by controlling the throttling loss of the valve;improve hydraulic system efficiency by recovering potential energy.In order to utilize the wasted potential energy,a new potential energy recovery scheme is proposed.In this paper,the energy recovery principle of a variable-position asymmetric axial piston pump(VAPP)controlled differential cylinder system was analyzed;Then the simulation model of hydraulic system energy recovery was established by using ITI-Simulation X software;Finally,the feasibility of the hydraulic system energy recovery scheme was demonstrated through experiments.The energy recovery efficiency of(VAPP)controlled differential cylinder system was studied by means of theoretical analysis,simulation calculation and experimental verification.In this study,the main working process is that the motor drives the VAPP to drive the hydraulic cylinder to make the object rise-fall-rise.VAPP’s distribution plate has 3 windows: Window A is connected to the hydraulic cylinder without rod cavity;Window B is connected to the hydraulic cylinder with rod cavity;And window C is connected to the accumulator.The hydraulic system mainly recovers the potential energy generated by the hydraulic cylinder driving object in the process of falling through the accumulator in order to achieve the energy saving effect.The energy saving effect is calculated by comparing the energy consumed by the motor when driving the VAPP-driven hydraulic cylinder to make object rise twice.Meanwhile,the influence of key parameters,such as load,motor speed,VAPP swashplate angle,accumulator pressure and capacity,etc.,on the potential energy recovery efficiency and system performance were analyzed.The results show that the system energy consumption can be reduced effectively by using the potential energy recovery system.When the object is in the descent process,the potential energy is stored in the accumulator.The motor drives the VAPP-driven hydraulic cylinder to raise the object in the second time consume 1.90 k J less energy than that in the first lift.At the same time,the time taken for the load to rise from the lowest position to the highest position for the second time is 0.88 s shorter than that for the first lifting position.By comparing the flow of VAPP in the two rising processes,it was found that the flow of port A in the VAPP increased significantly during the second ascent.By analyzing the key parameters affecting the energy recovery of the hydraulic system,it is found that different parameter settings will produce different results for the energy saving effect of the system.Finally,it is obtained by comparison that when the load,motor speed,pre-charge pressure and capacity of the accumulator,and swashplate angle are 440 kg、1000 rpm、3.5 MPa、6.3 L and ± 5 ° respectively,the system’s energy-saving effect can be up to 42.09%.