Research On Slewing Energy Saving Of Hydraulic Excavator Based On Accumulator Energy Recovery

As one of the most important national infrastructure construction machinery, hydraulic excavators have been widely used in the fields of construction、transportation、water conservancy、mining、military and so on. However, the working condition of the hydraulic excavator is very complicated, and the load changes acutely, The engine often works in the inefficient zone, fuel utilization rate is low, so, efficiency、energy-saving and emission reduction have always been one of the main objectives pursued by the world. For the ordinary slewing system of the hydraulic excavator, the energy loss is mainly caused by two aspects: First, the overflow loss produced when the slewing system starts, and secondly, the kinetic energy of the slewing platform will loss in the form of heat when the slewing system brakes, so in order to solve the above consumption problems, Based on Japan Komatsu excavator of PC220-8, a new slewing system for hydraulic excavators based on accumulator energy recovery was proposed in this paper, and related researches were studied.The main contents are as follows:1、Through researching and reading relevant literature, understand the energy-saving research of hydraulic excavators’whole system and slewing system at present, find out the deficiency of the present study, and lay foundations for proposing more efficient slewing system.2、Through analysing the advantages and disadvatanges of each energy storage elements, the new system chooses the accumulator as the energy storage element, and a new slewing braking energy recovery system is proposed based on the accumulator, which uses the electronic control technology, through the pressure transducer to distinguish the braking energy recovery. According to the different ways of the energy release, two schemes are proposed: scheme one, the high pressure oil of the accumulator is released to the inlet of the rotary motor, to drive the rotary motor directly, so this scheme is called direct utilization scheme; scheme two, the high pressure oil of the accumulator is released to the inlet of the pump to reduce the differential pressure of the inlet and outlet, so this scheme is called indirect utilization scheme.3、Based on the AMESim software, the simulation models of the ordinary slewing system、 scheme one system and scheme two system are built, then the flow and energy utilization efficiency of the excavator are analyzed. The simulation results show that:because the traditional scheme equipes with no braking energy recovery system, the flow and energy utilization efficiency are very low, and the scheme one system equips with the braking energy recovery system, also having the appropriate control strategy, so the efficiency reaches to the perfect state; although the scheme two system equipes with the braking energy recovery system, compared to the scheme one, the efficiency is lower.4、For the scheme one system, the simulation analysis is carried out from three aspects: energy recovery efficiency、reuse efficiency of the recovered energy and the system efficiency. The simulation results show that:the hydraulic excavator which was equipped with the slewing braking energy recovery had an energy recovery efficiency of66.9%, the energy recovery recycling efficiency was50.3%, and the system energy efficiency was49.9%. Finally, the effects on the energy recovery efficiency、reuse efficiency of the recovered energy and the system efficiency for the accumulator and the slewing platform’s moment of inertia are researched.5、In order to prove the feasibility and energy effect for the new slewing braking energy recovery system, the experiment scheme and platform are designed, and the lad experiment principle is described From the three aspects:the experimental scheme and principle、the experimental equipment and instrument and the experimental data acquisition platform.