Hydraulic working machine

A hydraulic working machine, comprising:

• an engine,
• a variable displacement hydraulic pump drivable by power transmitted from the engine,
• a hydraulic actuator drivable by pressure oil delivered from the variable displacement hydraulic pump,
• an actuator control valve for controlling a flow of pressure oil fed from the variable displacement hydraulic pump to the hydraulic actuator the actuator control valve being arranged to permit switching between a feed state in which pressure oil delivered from the variable displacement hydraulic pump is to be fed to the hydraulic actuator and a non-feed state in which the pressure oil is returned to a hydraulic oil reservoir without feeding the pressure oil to the hydraulic actuator,
• an exhaust gas purification system having a filter for trapping particulate matter in exhaust gas produced from the engine, and
• an exhaust gas temperature raising processing means for performing, when the actuator control valve is in the non-feed state and clogging has occurred on the filter, processing to increase a load acting on the engine such that a temperature of the exhaust gas is raised to a temperature needed to burn the particulate matter,
• wherein the exhaust gas temperature raising processing means includes:
• an electric assist motor connected to an output shaft of the engine,
• an inverter for adjusting a torque of the electric assist motor, and
• a controller that respectively determines whether or not the actuator control valve is in the non-feed state and whether or not clogging has occurred on the filter of the exhaust gas purification system,
• wherein, when the controller determines that the actuator control valve is in the non-feed state and clogging has occurred on the filter, the controller drives the electric assist motor to increase the load acting on the by controlling the inverter to adjust a torque of the electric assist motor so that electric power is generated by the electric assist motor, and
• wherein the controller lowers a target rpm of the engine to a level needed for the variable displacement hydraulic pump to deliver pressure oil at a lowest delivery rate required for cooling and lubricating a hydraulic circuit included in a drive system of the hydraulic working machine.