Mobile crane and engine revolution speed control method, engine revolution speed control device and engine revolution speed control system thereof

The invention discloses a mobile crane and an engine revolution speed control method, an engine revolution speed control device and an engine revolution speed control system thereof. The control method includes the following steps: the current load rate of an engine is acquired when the control signal of an accelerator pedal is not received in the hoisting condition; and according to the current load rate of the engine, the revolution speed of the engine is regulated. The control device comprises a load rate acquisition unit and a first revolution speed regulation unit; the load rate acquisition unit is used for acquiring the current load rate of the engine when the control signal of the accelerator pedal is not received in the hoisting condition; and the first revolution speed regulation unit is used for regulating the revolution speed of the engine according to the current load rate of the engine. The invention can achieve the purpose of matching the revolution speed of the engine with load, and prevents the problems of oil waste, equipment abrasion and the like which are caused when the control on the revolution speed of the engine only depends on the signal of the accelerator pedal; and the invention has the advantages that the automation degree of engine revolution speed control is increased, the labor intensity of drivers is decreased, oil consumption is reduced, and energy is saved.