Vehicle crane, energy-saving control method and energy-saving control system thereof

Disclosed are an energy-saving control method and system for a vehicle crane. The energy-saving control system includes a joystick for providing a flow demand signal of a hydraulic system of the vehicle crane, a pressure sensor for detecting the load pressure of the hydraulic system, and a controller signally connected with the joystick and the pressure sensor. The energy-saving control method includes the following steps of providing the flow required by the hydraulic system of the vehicle crane through the joystick and detecting the load pressure of the hydraulic system through the pressure sensor; calculating by utilizing an energy-saving algorithm module or searching the minimum value of an engine fuel consumption per unit time at current load within the set changing range of the current rotating speed; and adjusting the engine rotating speed to correspond to the minimum value of the fuel consumption per unit time, and adjusting the displacement of a variable displacement pump of the hydraulic system to be match with the rotating speed. A vehicle crane having the energy-saving control system is also disclosed. Combined control of the engine rotating speed and the displacement of the variable displacement pump is realized in the present invention by enabling the input from the joystick to directly correspond to the flow of the hydraulic system.