Patent ID: 8321094

Claim:
An engine control system for a construction machine provided with a turbocharged engine, an electric motor and hydraulic pump drivable by the engine, a hydraulic actuator operable by pressure oil delivered from the hydraulic pump, a control device for controlling the hydraulic actuator, and a capacitor capable of feeding electric power to the electric motor, characterized in that the engine control system is provided with a load condition detecting means for detecting a condition that a torque to be absorbed the hydraulic pump would exceed an output torque of the engine, a charge amount detecting means capable of detecting an amount of charge in the capacitor, a boost pressure sensor, and a determination processing means for performing processing to feed electric power from the capacitor to the electric motor if, when the condition that a torque to be absorbed the hydraulic pump would exceed an output torque of the engine has been detected by the load condition detecting means in concomitance with manipulation of the control device, a boost pressure detected by the boost pressure sensor is determined to be lower than a predetermined pressure, and moreover, an amount of charge in the capacitor as detected by the charge amount detecting means is determined to be an amount of charge that can drive the electric motor for a predetermined time.