Research on Energy Saving Technology of Load Sensitive Variable Steering System for Vehicles

In view of the large energy loss problem in the traditional full hydraulic steering system,a scheme of replacing the ordinary pump with the priority valve with the load sensitive variable pump is proposed to make the variable pump provide the corresponding flow rate according to the needs of the steering system to achieve the purpose of energy saving.Through the establishment of the system AMESim simulation model,the data comparison shows that the energy loss of the load sensitive variable steering system is significantly reduced relative to the traditional full hydraulic steering system.

Multi-parameter load sensing pump model simulation and flow rate characteristics research

Load sensing pumps have been widely used in diverse hydraulic systems.Studies show that structural parameters have undeniable impacts on the characteristics and efficiency of the load sensing pump.The main purpose of this article is to study the influence of load sensing pump structure parameters on flow characteristics.In the present study,a nonlinear multi-parameter model is proposed for this type of pump.In this model,different parameters,including spool clearance,spool covering amount,internal leakage are considered to reflect the displacement adjustment process of the load sensing pump.Moreover,a frequency sweep method is proposed to analyze the frequency domain of the nonlinear mathematical model.An experiment rig was built to study the influence of key structural parameters on the dynamic follow-up characteristics of the pump flow.The obtained results show that the diameter of the orifice d can significantly affect the working characteristics of the pump.It is found that a large diameter of the orifice d can improve the phase following ability of the system,while a small diameter of the orifice d can reduce the bypass flow rate and increase the amplitude following ability.This paper provides a new consideration to study the dynamic follow-up characteristics of the load sensing pump.

Experimental investigations of a prototype reversible pump turbine in generating mode with water head variations

Influences of water head variations on the performances of a prototype reversible pump turbine are experimentally studied in generating mode within a wide range of load conditions(from 25% to 96% of the rated power). The pressure fluctuations of the reversible pump turbine at three different water heads(with non-dimensional values being 0.48, 0.71 and 0.90) are measured and compared based on the pressure data recorded in the whole flow passage of the turbine. Furthermore, effects of monitoring points and load variations on the impeller-induced unstable behavior(e.g. blade passing frequency and its harmonics) are quantitatively discussed. Our findings reveal that water head variations play a significant role on the pressure fluctuations and their propagation mechanisms inside the reversible pump turbine.