ENGINE LAG-DOWN PREVENTION DEVICE FOR HYDRAULIC CONSTRUCTION MACHINE

摘要

PROBLEM TO BE SOLVED: To reduce the lag-down of an engine generated at the urgent operation time of a hydraulic actuator from a non-operation state without generating the deterioration of a fuel consumption and the increase in a black smoke, in a hydraulic construction machine adopting a big engine as a prime mover. SOLUTION: When an operation lever 4a is not operated and a pressure switch 11 is turned OFF, a hydraulic pump 2 is a minimum slant running and an engine 1 runs with a high idle number of rotation. When the operation lever 4a is operated and the pressure switch 11 is turned ON, the control of the hydraulic pump 2 is converted from the minimum slant running control to a torque reduction control and converted to a rated torque control after the elapsing of a prescribed timeΔtA. When the operation lever 4a is returned to a neutral and the pressure switch 11 is turned OFF again, the control of the hydraulic pump 2 is converted from the rated torque control to the minimum slant running control after the elapsing of a prescribed timeΔtB.