Due to the complex working process of excavators, there are both heavy load excavation and light load leveling, and there are loose soil excavation and hard soil excavation. Therefore, in order to adapt to different working environment, the system needs to control by working condition. According to the different working environment, excavators are divided into three power modes: H mode (heavy load mode), S mode (energy saving mode) and l mode (light load mode). The power distribution of the three power modes is 100%, 85% and 60% of the rated power of the engine respectively.
Because the diesel engine is basically regulated by constant torque, the change of output power shows the change of output speed, that is, different throttle opening corresponds to different diesel engine speed. Therefore, the system needs to set the maximum no-load speed of the engine under three power modes.
