| 摘要 |
PURPOSE:To enable output maintaining engine horsepower fit for work load without the generation of an engine stalling by outputting a rotating speed reducing command signal to a governor from a controller upon judging engine output to be larger than pump absorption horsepower. CONSTITUTION:A pressure signal from a pressure sensor 33 provided at a main circuit 36 on the discharge side of a first pump 25 is inputted to a controller 35. On the basis of this pressure signal, the controller 35 outputs a pump inclined rotation command signal to the regulator 27 of the first pump 25 through a solenoid proportional pressure reducing valve 30. The controller 35 also computes pump absorption horsepower on the basis of the pressure signal and the pump inclined rotation signal, and relatively computes the pump absorption horsepower and engine horsepower, based on an engine performance curve in engine speed at that time, only for the specified working time. Upon judging engine output to be larger than the pump absorption horsepower, the controller 35 outputs an engine speed reducing command signal to the governor 21 of an engine 20. |
