The working conditions of hydraulic excavator are bad, the working period is long, the external load changes sharply, and the working point of diesel engine fluctuates frequently. Before that, the energy saving control of hydraulic excavator mainly focused on the matching of engine output power with hydraulic pump outlet power and engine throttle adjustment. However, it can not fundamentally solve the negative impact of severe fluctuation of external load on engine efficiency.
At present, in the research of energy saving control of hydraulic excavator, the engineering design method of hybrid power is introduced. The motor is used to balance the fluctuation of external load, which makes the working point of engine relatively stable. Thus, the fuel consumption and emission characteristics of hydraulic excavator are improved, and the energy saving control of hydraulic excavator is realized. In this field, a prototype of parallel and series hybrid excavator is developed, and then based on parallel hybrid hydraulic excavator structure, asynchronous motor and super capacitor are introduced into the system. Build a parallel hybrid hydraulic excavator experimental platform. Based on the system structure of parallel hybrid hydraulic excavator, the motor and battery unit are introduced to maintain the engine working in the economical and efficient area, which involves the conversion of multiple energy. Therefore, in the study of energy saving control of hybrid hydraulic excavator, besides analyzing the fuel consumption characteristics of diesel engine, the energy conversion efficiency and dynamic characteristics of various components of power source should be analyzed and compared.