Abstract: An engine control device of a work machine controls an internal-combustion engine of the work machine including a swing body, an implement attached to the swing body, a hydraulic actuator that operates the implement, a hydraulic pump that operates the hydraulic actuator, and the internal-combustion engine that drives the hydraulic pump and of which a rotation speed is changed according to a load. The engine control device of the work machine includes: a determination unit configured to determine whether a condition not requiring work with the implement is established; and an engine control unit configured to enable control at relief time of determining a target rotation speed targeted by the internal-combustion engine based on horsepower sucked by the hydraulic pump of when a hydraulic oil ejected by the hydraulic pump is relieved when the condition is established, and disables the control at relief time when the condition is not established.

Abstract: A hybrid work machine engine control device which is mounted on a hybrid work machine having a working unit that operates with operating oil supplied from a hydraulic pump and which controls an internal combustion engine that drives a generator motor and the hydraulic pump with generated power, includes: a processing unit that increases torque required for the generator motor to generate electric power with a lapse of time and decreases absorption torque that the hydraulic pump absorbs when the generator motor generates electric power during operation of the internal combustion engine.

Abstract: An engine control device of a work machine controls an internal-combustion engine of the work machine including a swing body, an implement attached to the swing body, a hydraulic actuator that operates the implement, a hydraulic pump that operates the hydraulic actuator, and the internal-combustion engine that drives the hydraulic pump and of which a rotation speed is changed according to a load. The engine control device of the work machine includes: a determination unit configured to determine whether a condition not requiring work with the implement is established; and an engine control unit configured to enable control at relief time of determining a target rotation speed targeted by the internal-combustion engine based on horsepower sucked by the hydraulic pump of when a hydraulic oil ejected by the hydraulic pump is relieved when the condition is established, and disables the control at relief time when the condition is not established.

Abstract: A construction machine includes a swing speed detection unit that detects an actual swing speed of an upper structure, a lever command speed calculation unit that calculates a lever command speed based on an operation amount of a swing lever for swinging the upper structure, a torque command value calculation unit that calculates a torque command value based on a command speed based on the calculated lever command speed, a command value output unit that outputs a command torque to a rotary motor generator based on the torque command value calculated by the torque command value calculation unit and the swing speed detected by the swing speed detection unit, and a command value output restriction unit that restricts the output of the torque command value from the command value output unit under predetermined conditions.

Abstract: In controlling an engine generating motive power of which an output shaft extracting the generated motive power is connected to a generator motor, an engine control device causes the generator motor to generate motive power when both of a first condition satisfied based on a comparison of an actual revolution speed of the engine with a revolution speed acquired from first and second relationships and a second condition satisfied based on a comparison of a torque of the engine at the actual revolution speed with a torque acquired using the first relationship at the actual revolution speed are satisfied. The first relationship is between the revolution speed of the engine and the torque generated by the engine at the revolution speed, and the second relationship is between the torque and the revolution speed of the engine and defines a magnitude of the motive power generated from the engine.