A fuel-efficient hydraulic fluid has a lower viscosity than a standard hydraulic fluid, a pressure loss decreases, and thus, when control based on a standard model is exercised, the speeds of various actuators increase. However, the speeds need not be incr...

A hydraulic drive system executing the load sensing control is designed to be capable of efficiently combusting and removing filter deposits inside an exhaust gas purification device (42) by pump output power increasing control when there is no actuator op...

A traveling hydraulic working machine comprises input means 42, 43 for commanding a target revolution speed of an engine 1, first detection means 44, 47 for detecting an operating situation of a hydraulic actuator 13, etc., second detection means 45, 46 fo...