Patent attributes
Provided is a hybrid work machine in which a hybrid system and a downsized engine are used. The hybrid work machine performs rapid charging of a power storage device while preventing decreases in the output power of a hydraulic pump. A vehicle body controller performs engine revolution speed decreasing control in which, if the charge rate of a battery becomes equal to or less than a minimum charge rate, the target revolution speed of an engine is reduced. The vehicle body controller also performs torque reducing control in which the maximum absorption torque of a hydraulic pump is reduced. By performing these control operations, the vehicle body controller coercively generates surplus torque for the engine and operates a generator-motor as a generator.