Pump-Controlled Actuators with Dump Valves

Abstract

The electrification trend means an increased focus on the energy efficiency of mobile hydraulic systems. In turn, this means an increased focus on so-called pump-controlled systems, where actuators are controlled by pump flow rather than valve throttling. However, one of the main problems with pump-controlled systems is matching the flow into the pump with its outlet flow. There are many ways of solving this problem, but the solutions tend to be rather bulky and not ideal from a service perspective, since they often rely on accumulators. This paper presents simple but novel pump-controlled concepts, without accumulators. The energy consumption of the presented concepts is analysed and compared to other concepts. The analysis is based on measurements taken on a backhoe loader and the results show that implementation of the presented concepts on the backhoe’s boom actuator can reduce the total power consumption by 50-60 % compared to the original load sensing system. This can be compared with 55-65 %, which is the yield for an ideal, accumulator-based, pump-controlled system on the boom.