Patent attributes
A construction machine includes: one or more hydraulic pumps discharging a working fluid; an engine supplying a rotational power to the hydraulic pumps; a hydraulic line through which the working fluid discharged by the hydraulic pumps moves; a main control valve provided on the hydraulic line and controlling supply of the working fluid to a traveling device or one or more of various working devices, which require the working fluid; a bypass cut valve provided on the hydraulic line at a lower side thereof than the main control valve to open and close the hydraulic line; an automatic warm-up switch generating a warm-up operation signal for raising a temperature of the working fluid before an operation starts; and a control device performing a warm-up operation for increasing the number of revolutions of the engine and opening the bypass cut valve to increase a flow rate along the hydraulic line, when the warm-up operation signal is received from the automatic warm-up switch.
