Reducing the fluid fluctuation of three-cylinder ERD by optimizing the overlap function and improving the resistance loss uniformity

Abstract

Although the three-cylinder energy recovery device (TC-ERD) can simultaneously achieve the continuous flow of high and low pressure fluids, the change in resistance loss of the fluid channel during the stroke alternating will still cause flow fluctuation, which can be improved by optimizing overlap function. In this paper, the overlap function is optimized by adjusting the forward execution time (t1) of switcher, and the high-pressure overlap can achieve “optimal-overlap” at t1 = 0.5 s. Moreover, the flow fluctuations of high and low pressure fluids decrease as t1 reduces. When t1 decreases from 3 s to 0.5 s, the flow fluctuation rate of high-pressure fluid at design capacity (30 m3/h) is reduced from 9.17% to 3.43%, and that of low-pressure fluid decreases from 5.2% to 1.83%. Additionally, when the three hydraulic cylinders are alternately pressurized (depressurized), the difference in resistance loss of three high-pressure (low-pressure) fluid channels will also cause the flow fluctuation of high-pressure (low-pressure) fluid. After improving the resistance loss uniformity, the flow fluctuation rates of high and low pressure fluids are further reduced to 0.53% and 0.89%, and the flow fluctuation amplitudes of high and low pressure fluids are hardly affected by capacity within the range of 50.0%–133.0% of design capacity.