液气储能双缸驱动大型液压挖掘机动臂节能特性研究

液压挖掘机工作过程中存在大量的重力势能浪费，严重影响整机能效并造成大的排放污染。针对双液压缸驱动动臂的大型液压挖掘机，提出采用双液气储能液压缸驱动液压挖掘机动臂、集成驱动与势能回收一体化原理，降低机器作业能耗和排放。将原双腔液压缸改为集成有储能腔的三腔液压缸，储能腔与液压蓄能器直接连通，通过液压蓄能器初始充液压力平衡工作装置自重，直接回收利用工作装置重力势能。根据36 t大型液压挖掘机作业特点和重力势能变化情况，设计出液压缸和液压蓄能器的参数。进一步建立数字化样机，通过对液气储能驱动系统进行仿真研究，对液压泵输出流量和控制阀的阀口参数重新匹配，修改了与回转复合动作的合流控制策略，并初步验证了液气储能驱动系统的节能效果。在此基础上构建了试验样机，90°标准装车作业循环测试表明，与同型号液压挖掘机相比，在满足同样挖掘力的情况下，整机工作效率提升20.7%，燃油消耗降低17.1%，如按每天作业8 h计算，单台车每天可节约燃油达47 L，减少二氧化碳排放123.6 kg。

Research on Energy Saving Characteristics of Large Hydraulic Excavator Boom Driven by Dual Hydraulic-gas Energy Storage Cylinder

There is a lot of gravitational potential energy waste in the working process of hydraulic excavators, which seriously affects the efficiency of the whole machine and causes large emission pollution. Aiming at the large hydraulic excavator of which the boom is driven by dual hydraulic cylinders, the principle of double hydraulic-gas energy storage cylinders driving the hydraulic excavator's boom and integrating driving and potential energy recuperation is proposed to reduce the energy consumption and emission of hydraulic excavators. In the implementation, the original two-chamber hydraulic cylinders are replaced by three-chamber hydraulic cylinders with energy storage chambers, and the energy storage chambers are directly connected with the hydraulic accumulator. The self-weight of working device is balanced by the initial hydraulic pressure of the hydraulic accumulator, and the gravitational potential energy is directly recuperated. Firstly, the parameters of three-chamber hydraulic cylinders and the hydraulic accumulator are designed according to the operation characteristics of 36 tons large hydraulic excavator and the variation of gravity potential energy. Then the digital prototype is further established. Through the simulation study of the proposed system, the hydraulic pump output flow and the valve port parameters of the control valve are re-matched. The flow control strategy of compound action with swing is modified, and the energy saving effect of the hydraulic-gas energy storage driving system is preliminarily verified. A test prototype is constructed according to the foundation. The 90-degree standard loading cycle tests show that compared with the existing hydraulic excavators of the same type, in the case of meeting the same digging force, the working efficiency of the excavator increases by 20.7% and the fuel consumption decreases by 17.1%. In terms of 8 hours of work per day, a single excavator can save fuel up to 47 L per day and reduce carbon dioxide emissions by 123.6 kg.