Abstract: A hybrid work machine is configured with an engine 41, a hydraulic pump 51, a hydraulic actuator, a generator motor 61 coupled to the engine 41, an electric storage device 62 that transmits and receives electric power to and from the generator motor 61, an engine controller 42 that controls the engine 41 based on a target engine revolution speed, a power controller 63 that controls action of the generator motor 61, a controller 72 that controls the engine controller 42 and the power controller 63, and a target engine revolution speed change instructing device that give instructions on a change in the target engine revolution speed. The controller 72 controls the engine controller 42 and the power controller 63 to act the generator motor 61 as a generator until an actual revolution speed of the engine 41 is reduced to a revolution speed corresponding to a target engine revolution speed after change if the target engine revolution speed has been changed to be lower while the engine 41 is in an unloaded state.

Abstract: A hybrid work machine is configured with an engine 41, a hydraulic pump 51, a hydraulic actuator, a generator motor 61 coupled to the engine 41, an electric storage device 62 that transmits and receives electric power to and from the generator motor 61, an engine controller 42 that controls the engine 41 based on a target engine revolution speed, a power controller 63 that controls action of the generator motor 61, a controller 72 that controls the engine controller 42 and the power controller 63, and a target engine revolution speed change instructing device that give instructions on a change in the target engine revolution speed. The controller 72 controls the engine controller 42 and the power controller 63 to act the generator motor 61 as a generator until an actual revolution speed of the engine 41 is reduced to a revolution speed corresponding to a target engine revolution speed after change if the target engine revolution speed has been changed to be lower while the engine 41 is in an unloaded state.

Abstract: A main controller 28 performs automatic stop control to stop an engine in a case where a preset automatic stop condition is satisfied, and includes a power source control processing section 283 controlling power supplied from a capacitor to an electric or electronic facility 70. The power source control processing section 283 estimates a charge amount by which the capacitor 40 is charged by the alternator 41 while an engine 9 is in operation, estimates an electric discharge amount corresponding to power supplied from the capacitor 40 to the electric or electronic facility 70 while the engine 9 is stopped under the automatic stop control, and stops supply of power from the capacitor 40 to the electric or electronic facility 70 when the electric discharge amount is determined to be larger than the charge amount while the engine 9 is stopped under the automatic stop control. This allows reliable suppression of degradation of the capacitor while the engine is under the automatic stop control.

Abstract: A work machine that can prevent restarting of an engine against a will of an operator from an idle stop state is provided. A hydraulic excavator includes a display device that displays a confirmation screen image for allowing an operator to confirm whether or not an engine is to be restarted from an idle stop state, and an inputting device that allows the operator to input a restart instruction for the engine in an interlocked relationship with the display of the confirmation screen image. A machine controller includes a restart controlling section that restarts the engine based on the restart instruction for the engine inputted by the inputting device.

Abstract: A work machine that can prevent restarting of an engine against a will of an operator from an idle stop state is provided. A hydraulic excavator includes a display device 52 that displays a confirmation screen image 58 for allowing an operator to confirm whether or not an engine 32 is to be restarted from an idle stop state, and an inputting device 54 that allows the operator to input a restart instruction for the engine in an interlocked relationship with the display of the confirmation screen image 58. A machine controller 100 includes a restart controlling section 118 that restarts the engine 32 based on the restart instruction for the engine inputted by the inputting device 54.