Prime mover revolution speed control system for hydraulic construction machine

摘要

The present invention provides a prime mover revolution speed control system for a hydraulic construction machine is capable of identifying an excavation state with increased certainty to improve operational performance during excavation work and enhance work efficiency. When the control lever (44) is fully operated in the direction of arm crowding, the control lever (43) is also operated, and PD‰§13 MPa applied, first judgment conditions are all met to let the excavation state identification function (62) conclude that an excavation state has begun. The function (64) determines NR by adding ”N to NRO, and then starts a speedup sequence. During excavation work, if the control lever (44) is subjected to a half or greater operation in the arm crowding direction and PD‰§10 MPa is applied, second judgment conditions are all met to let the function (62) conclude that the excavation state has persisted, and continue with the speedup sequence. If the second judgment conditions are not met, the function (62) concludes that the excavation state has ended, and then terminates the speedup sequence.