Claims
- 1. An electronic control method for enhancing the efficiency of electric motor driven propeller watercraft comprising:
(a) detecting the speed of the watercraft directly or indirectly; (b) detecting the rotational speed of the electric motor; (c) comparing the result of step (a) with the result of step (b) to estimate an expected propeller slip; and (d) adjusting power to the motor to achieve a desired propeller slip.
- 2. A control method as described in claim 1, wherein step a is carried out by a procedure selected from the group consisting of detecting a signal or difference from a GSA receiver; detecting a signal or signal difference from a speedometer; and inputting a value from by a computer that monitors at least one electrical variable of the motor selected from the group consisting of power, voltage and running time.
- 3. A control method as described in claim 1, wherein step b is carried out by a procedure selected from the group consisting of detecting the motor rotational speed; indirectly determining the motor speed by detecting the current in the motor armature, the voltage of the motor armature, the impedance of the motor armature, the current in the motor field winding, the voltage of the motor field winding, and/or the impedance of the motor field winding.
- 4. A control method as described in claim 1, wherein the desired propeller slip is less than 50%.
- 5. A control method as described in claim 1, wherein the rotational speed of the electric motor is determined by sensing the voltage of the motor power.
- 6. A control method as described in claim 1, wherein the motor is adjusted in step d) to provide lower slip with faster boat and propeller speeds.
- 7. The electronic control of claim 1, wherein the speed of the boat is inferred from a piezo electric sensor located at the boat hull to water surface.
- 8. An electronic control for enhancing the high speed efficiency of a displacement electric motor driven watercraft comprising:
a) a motor current measurement signal; b) a motor voltage measurement signal; and c) a comparator for monitoring the current and voltage signals, wherein the controller limits voltage to the motor upon sensing an overly high increase in motor current upon increasing motor voltage.
- 9. The electronic control of claim 8, wherein the overly high increase in motor current is more than 25% higher than the increase seen at low boat speed measured between 10% and 70% of the hull speed.
- 10. An electronic control device that controls propeller slip of an electric motor powered watercraft, comprising:
a) a detector of propeller speed; b) a detector of the watercraft's speed, and b) a circuit that controls power to the armature of the motor, a field winding of the motor or both, wherein a signal from the detector actuates the circuit to adjust propeller slip according to a predetermined relationship between propeller and boat speed.
- 11. An electronic control device as described in claim 10, wherein the detector is selected from the group consisting of a motor speed detector, voltage input to the motor, an optic or magnetic sensor of propeller speed and a computer that monitors power and time to estimate approximate speed.
- 12. A watercraft that contains an electronic control device as described in claim 10.
- 13. An electronic control device as described in claim 10 wherein the circuit decreases power to the motor when the propeller speed exceeds a predetermined limit for a given boat speed.
- 14. An electronic control device as described in claim 10, wherein the predetermined relationship between propeller and boat speed is a single value for all boat speeds.
- 15. An electronic control device as described in claim 10 further comprising at least a second control condition that increases the allowable propeller slip to provide higher slippage for greater acceleration.
- 16. A non-mechanical electronic control system for inhibiting cavitation of a propeller driven electric powered watercraft, comprising:
a) a boat speed monitor; and a) a control circuit, wherein the control circuit monitors motor voltage as an index of propeller speed and decreases motor power when the motor voltage is too high for a given boat speed.
- 17. A non-mechanical electronic control system as described in claim 16, wherein the control circuit contains a microprocessor look up table of motor voltage versus boat speed values for use in determining when to lower motor power.
- 18. A non-mechanical electronic control system as described in claim 16, wherein the boat speed monitor is a piezo electric transducer located at a surface of the boat hull in contact with water.
- 19. A simplified heading cruise control for a watercraft, comprising:
a) one or more ratiometric output geomagnetic sensors mounted to the watercraft and that output one or more analog signals that correspond to geomagnetic heading; b) a circuit that analyses the signal(s) from the one or more geomagnetic sensor(s) to output one or more correction signals for altering course; and c) a maximum of one on/off switch on the watercraft dash required for activating the cruise control.
- 20. A simplified cruise control for a watercraft as described in claim 19, further comprising a propeller speed or boat speed signal that automatically turns on the heading cruise control upon exceeding a set speed to allow automatic heading correction at higher cruise speeds.
- 21. A simplified heading cruise control as described in claim 19, further comprising a switch mounted on at least the motor throttle or steering wheel control, wherein activation of the switch turns the heading cruise control on or off, and wherein the switch is a body capacitive switch that is activated upon electrical contact between skin of the watercraft operator and the throttle or steering control.
- 22. A simplified heading cruise control as described in claim 19, further comprising a rotating knob for directly setting a desired course, wherein the one or more ratiometric output geomagnetic sensors are attached to the rotating knob and rotate with the knob.
RELATED APPLICATION DATA
[0001] This application is a continuation in part of U.S. Ser. No. 09/877,196 filed Jun. 11, 2001 and also receives priority from U.S. Nos. 60/296,754 filed Jun. 11, 2001; 60/302,647 filed Jul. 5, 2001 and 60/349,375 filed Dec. 22, 2001.
Provisional Applications (3)
|
Number |
Date |
Country |
|
60296754 |
Jun 2001 |
US |
|
60302647 |
Jul 2001 |
US |
|
60349375 |
Jan 2002 |
US |
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
09877196 |
Jun 2001 |
US |
Child |
10164566 |
Jun 2002 |
US |