Power output apparatus and method of controlling the same

Abstract

A power output apparatus (20) of the invention includes an engine (50), a clutch motor (30), an assist motor (40), and a controller (80) for controlling the clutch motor (30) and the assist motor (40). In response to an engine stop signal to stop operation of the engine (50), the controller (80) successively lowers a torque command value of the clutch motor (30) and a target engine torque and a target engine speed of the engine (50) to make the engine (50) kept at an idle. The assist motor (40) is controlled to use power stored in a battery (94) and make up for a decrease in torque output to a drive shaft (22) accompanied by the decrease in torque command value of the clutch motor (30). When the engine (50) falls in the idling state, supply of fuel into the engine (50) is stopped to terminate operation of the engine (50). In this state, the drive shaft (22) is driven and operated only by the torque of the assist motor (40), which is generated by the power stored in the battery (94). This control procedure can stop the engine (50) without varying the torque output to the drive shaft (22).