Research On Characteristics Of Three-chamber Hydraulic Cylinder Driving Loader Boom

Loader is a kind of construction machinery witch plays an important role in the national economic construction.Because of its large quantity and low work efficiency,a very extensive research on energy saving and emission reduction has been carried out.As an important part of the loader,the hydraulic system will directly affect energy consumption characteristics and market competitiveness of loader.Its actual working conditions are complex,and the external load changes frequently and fluctuates violently.The peak power of the pump is large when the boom lifted,while the gravity potential of the working device is converted into heat by throttling loss when lowered,which rises temperature of the oil and cuts down working efficiency.Therefore,it is one of the effective ways to improve the energy utilization efficiency of engineering machinery by recovering and reusing of gravity potential energy of the lifting device.This paper proposes a potential energy recovery system that loader arm dead-weight hydraulic-gas balance based on three-chamber hydraulic cylinder.The C oil chamber is directly connected to accumulator,A and B chamber is connected to original hydraulic circuit.When the boom is lowered,the high pressure oil in the C chamber is introduced into the accumulator because of gravity,and the potential energy is converted into hydraulic energy and stored in the accumulator;when the boom is lifted,the accumulator releases the high pressure oil,and the auxiliary hydraulic pump is driving arm risesing,and the potential energy is recovered and reused during the lifting process by balancing the dead-weight.First built a 3-D model of wheel loader by Pro/E software,and import the 3-D model into the software SimulationX to build the dynamic model of wheel loader.While built the simulation model of hydraulic system using the software,and got the co-simulation model of wheel loader.Simulation and test research on boom descent-lifting in no-load conditions.Compared the simulation and experimental test results,the co-simulation model of wheel loader was accurate.three-chamber cylinder model established is used to replace the original cylinder,the hydraulic circuit connecting accumulator to the C chamber of three-chamber is added,and the new co-simulation model based on three-chamber cylinder is established.Then had a simulation to analyze the energy consumption of two kinds of typical working process,the simulation show that when the initial pressures of accumulators are 6Mpa and 8Mpa on the no-load and heavy-load,the system has the highest energy utilization rate.A prototype of wheel loader based on three-chamber hydraulic cylinder is established.the operating characteristics and energy efficiency characteristics of the boom driven by two-chamber cylinder and the three-chamber cylinder are studied experimentally.Connect the signal test circuit and the data acquisition system to build a loader test platform based on a three-chamber hydraulic cylinder.The boom lifting test was carried out under no-load and heavy-load conditions respectively.The test results show that the new system has good energy-saving effect and makes the arm running process more stable.Finally,a power matching scheme and control strategy based on the universal characteristics of the diesel engine are proposed.The number of working cylinders of the diesel engine is changed according to the working conditions of the loader.The diesel engine cylinder shut-off technology is used to match the output torque with the real-time load of the loader.The diesel engine works at the optimal fuel efficiency zone can further reduce the fuel consumption of the whole machine,which has certain guiding significance for the research of energy saving and emission reduction of loaders.