Engine Lag Down Suppressing Device of Construction Machinery

摘要

An engine lag down suppressing device of construction machinery, comprising a vehicle body controller ( 13 ) having a first torque control means and a second torque control means, and a third torque control means. The first torque control means controls a torque control valve ( 7 ) to the minimum pump torque (value: Min) according to a target engine rotational speed (Nr) when the operating device ( 5 ) in the non-operated state of an continues for a monitoring time (TX 1 ) to suppress an engine lag down after a specified holing time to hold a torque to a low pump torque is passed when the operating device in the non-operated state is operated. The second torque control means controls the torque control valve ( 7 ) to hold the minimum pump torque for a specified holding time (Tx 2 ) after the operating device ( 5 ) in the non-operated state is operated. The third torque control means comprises a solenoid valve ( 16 ) and controls the torque control valve ( 7 ) to gradually increase the pump torque with elapse of time from a time when the specified holding time (TX 2 ) is passed based on a specified torque increasing rate (K).