From the appearance characteristic curve of the diesel engine, it can be seen that the diesel engine is an approximate constant torque adjustment, and the change of its output power is represented by the change of the speed, but the output torque basically does not change. When the throttle opening increases (or decreases), the output power of the diesel engine increases (or decreases). Since the output torque is basically unchanged, the speed of the diesel engine also increases (or decreases), that is, different throttle openings correspond to different diesel engines. Rotating speed. It can be seen that the purpose of controlling the diesel engine is to realize the adjustment of the speed of the diesel engine by controlling the opening degree of the accelerator. The control devices used in hydraulic excavator diesel engines include electronic power optimization system, automatic idle speed device, electronic governor, electronic throttle control system, etc.