Patent ID: 8556668

Claim:
A marine propulsion device, comprising: a power transmission clutch provided on an input shaft to transmit a driving force from a main engine; a horizontal input/output shaft, one end side of which is connected to the input shaft through the power transmission clutch; a vertical shaft, one end side of which is connected to a substantially central part of the input/output shaft through a first turning mechanism; a horizontal propeller shaft, one end side of which is connected to another end side of the vertical shaft through a second turning mechanism; a propeller fitted to another end side of the propeller shaft, in which the propeller is driven by the main engine to propel a ship, and the propeller shaft and the propeller are revolved around the vertical shaft to set a propulsion direction of the ship; a motor generator connected to another end side of the input/output shaft; an inverter converting an alternating current into a direct current and a direct current into an alternating current, connected to a power supply to control the motor generator; and a controller, which propels the ship in a propulsion mode selected from a motor propulsion in which the power transmission clutch is disengaged from the input shaft to drive the motor generator as a motor, and a hybrid propulsion in which the power transmission clutch is connected to the input shaft to drive the motor generator as a motor or a generator with driving the main engine, wherein the controller calculates based on a steering wheel command signal output by a ship operator to designate a revolution number of the propeller and a load applied on the main engine, in response to a result of the calculation, the controller outputs a mode select signal for setting a control mode of the motor generator in a revolution number control mode or a torque control mode and an inverter command signal for driving the motor generator in a selected control mode to the inverter, and the controller further outputs a clutch control signal for connecting or disengaging the power transmission clutch to the power transmission clutch, and a governor command signal for commanding the revolution number to the main engine, thereby the controller controls the motor generator in the revolution number control mode in the motor propulsion in a motor propulsion region in which the revolution number of the propeller is equal to or less than a switching predetermined revolution number of the propeller, and the controller controls the main engine and the motor generator in the torque control mode in the hybrid propulsion in a hybrid region in which the revolution number of the propeller is equal to or more than the switching predetermined revolution number.