Electric motor assisted propulsion system for human-powered watercraft
View Patent ↗A propulsion system for watercraft for personal enjoyment that incorporates human power with electric motor assistance, energy storage and optional solar power to achieve increased watercraft speeds and/or reduced pedaling effort. Control electronics enable operator-adjustable electric motor assistance to the propulsion, thereby providing flexible pedal cadences and efforts and enjoyment for a wide variety of operators. An optional photovoltaic solar panel augments the power generation to extend travel time with motor assistance, and recharges the energy storage system. This invention enables a pleasure watercraft that is simultaneously lightweight, low cost, low maintenance, environmentally friendly with zero pollution, ultra-low noise, and thrilling to operate, while simultaneously providing a means of enjoyable exercise for operators of nearly all abilities.
1. An electric motor assisted marine propulsion system for a watercraft, comprising:
a manually-driven power input mechanism configured to accept human effort;
a propulsion mechanism comprising at least one propeller mounted on a propeller shaft for providing a propulsive thrust in water;
a mechanical drive train extending between the manually-driven power input mechanism and the propeller shaft, the mechanical drive train configured to transmit the human effort to the propeller shaft to rotate the propeller;
at least one electric motor mechanically coupled to the propeller shaft, wherein the electric motor is arranged to provide assisting power to the propeller shaft to drive the propeller;
an energy storage device configured to supply electrical power to the electric motor;
a control mechanism configured to control electrical power supplied to the electric motor as a function of the human effort, wherein a ratio of assisting power supplied by the electric motor and the human effort is variably and selectively adjustable by an operator; and
a housing enclosing the mechanical drive train, the electric motor and at least a substantial portion of the propeller shaft.
2. The propulsion system of claim 1 further comprising an operator interface enabling the operator to adjust the level of the assisting power supplied by the electric motor.
3. The propulsion system of claim 2 wherein the operator interface is mounted on or is integral with the housing of the propulsion system.
4. The propulsion system of claim 1 wherein the control mechanism comprises of an electronics unit mounted within the housing of the propulsion system.
5. The propulsion system of claim 4 wherein the electronics unit is configured to provide good thermal conduction from power switching devices to the surrounding water.
6. The propulsion system of claim 1 wherein the energy storage device is mounted within the housing of the propulsion system.
7. The propulsion system of claim 1 wherein the assisting power from the electric motor can be modulated to simulate travel through hills and valleys.
8. The propulsion system of claim 1 wherein the electric motor is controlled as a function of propeller speed.
9. The propulsion system of claim 1 wherein the electric motor is controlled as a function of a torque sensor signal.
10. The propulsion system of claim 1 wherein the electric motor is integrally mounted with the propeller shaft.
11. The propulsion system of claim 1 further comprising an operator interface enabling the operator to monitor performance parameters and operating information.
12. The propulsion system of claim 1 wherein the manually-driven power input mechanism comprises rotatable pedals.
13. The propulsion system of claim 12 wherein a reverse rotation of the pedals causes the propulsion mechanism to generate reversed thrust.
14. The propulsion system of claim 1 wherein the assisting power from the electric motor is modulated to simulate inertial effects.
15. A watercraft comprising the propulsion system of claim 1 .
16. The watercraft of claim 15 further comprising a photovoltaic system for powering the electric motor.