Hydraulic system for working machine

A hydraulic system for a working machine, the hydraulic system comprising:

• a prime mover;
• a hydraulic actuator;
• a control valve to control activation of the hydraulic actuator;
• a first hydraulic pump to be driven by power of the prime mover to deliver pilot fluid to switch the control valve;
• a second hydraulic pump to be driven by power of the prime mover to deliver hydraulic fluid to activate the hydraulic actuator, the second hydraulic pump being a variable displacement hydraulic pump;
• a first fluid passage to allow a highest load pressure, when the hydraulic actuator is activated, to act thereon;
• a second fluid passage to allow a delivery pressure of the hydraulic fluid from the second hydraulic pump to act thereon;
• a third fluid passage to which the first hydraulic pump delivers the pilot fluid;
• a fourth fluid passage branched from the third fluid passage;
• a hydraulic controller operable to control the second hydraulic pump to set a load-sensing (LS) differential pressure, the LS differential pressure being a pressure difference between the delivery pressure of the hydraulic fluid from the second hydraulic pump and the highest load pressure;
• the hydraulic controller including a solenoid valve to change a pilot differential pressure, the pilot differential pressure being a pressure difference between the pilot fluid that flows through the fourth fluid passage to act on the hydraulic controller and discharge fluid from the hydraulic controller;
• and
• a controller configured or programmed to control activation of the solenoid valve to adjust the pilot differential pressure to change the LS differential pressure.