ROTATION SPEED CONTROL DEVICE OF PUMP DRIVING ENGINE

摘要

PROBLEM TO BE SOLVED: To provide a rotation speed control device of a pump driving engine capable of suppressing noise and increasing delivery amount of a main pump. SOLUTION: The rotation speed control device comprises a throttle 2 for indicating a desired rotation speed of an engine 4 for driving the main pump 5, a rotation speed adjusting device including a motor 3 and a governor 4a for controlling real rotation speed of the engine 4, a pump pressure sensor 9 for detecting a delivery pressure of the pump 5, and a controller 1 for performing control so as to input a signal outputted from the throttle 2 and a signal outputted from the pump pressure sensor 9 and to output a desired engine speed for operating the motor 3. The controller 1 includes a setting means, namely a function generator 1f1 for keeping a locus of the real engine rotation speed to the variation of engine output torque T within a rotation speed region lower than a maximum rotation speed N4 during no load, and setting the locus so as to increase the real rotation speed than a rating rotation speed N3.