Study On Energy-Saving In Slewing Equipment Of Hydraulic Excavators

Hydraulic excavator has been paid much attention in the field of energy saving and environment protection, because of their large application quantities, high fuel consumption and bad emission. Nowadays, the researches on energy saving of hydraulic excavator mainly concentrate on three aspects:The first is improving the performance of working components, which has played an important role in increasing the system's efficiency, but it can't go any further; The second is reforming the hydraulic system. Reforming the hydraulic system is being regarded as an important research object because of its low efficiency in nature; The last is ameliorating the situation of power math for the diesel, hydraulic system and actuators, its aim is that the output energy of engine can be utilized adequately.The slewing platform of hydraulic excavator needs frequent start-up and braking to satisfy its working condition. During the braking process, the slewing motor has suffered the hydraulic impact which has turn into the heat and resulted in the energy loss of system. This paper has done a research on energy saving for this problem based on a 7-ton class hydraulic excavator.First of this paper, an AMESim model has been built and simulated according to the hydraulic system of the slewing platform based on the 7-ton class hydraulic excavator. The result of simulation tells that it is very necessary to have a research on energy saving in slewing platform of hydraulic excavator; finally, two energy-saving models of slewing platform have been built and simulated, and the energy recovery rate has been evaluated according to the result of the simulation.The hydraulic accumulator has the function of hydraulic energy recovery, so the first energy saving model has been built based on the characteristic of accumulator. The model has been simulated and the result turns out that the recovery rate is 10.29% though this model hasn't changed the whole hydraulic system of slewing platform too much.Secondary regulation has been developing a lot since years because of its remarkable energy recovery affection. So the second energy saving model has been built based on the technology of the secondary regulation and PID control has been used to control this system. This model has changed most of the former hydraulic system of slewing platform, for example, it uses a pump with constant pressure to take place of the variable pump, and the slewing motor with constant flow rate turn out to be variable. But the simulation result of this model has shown that it the energy recovery rate of this system reaches to 18.85%, and the speed of the slewing platform has performed a good stability.Finally, the paper has analyzed the energy recovery rate, the slewing speed, the advantage and the disadvantage of the three models according to the simulation results, and this can be a rule for the users to choose which model to use.