Claims
- 1. A signaling system for continuously reporting electric boat propeller efficiency, comprising:
(a) a transducer that generates an electrical signal proportional to boat speed; (b) a circuit that accepts the electrical signal proportional to boat speed and compares that signal with the voltage applied to the electric motor to output a signal; and (c) a signal display that receives the output signal and presents at least a visual or auditory signal indicating propeller efficiency.
- 2. A signaling system as described in claim 1, further comprising a cavitation alert signal that indicates when excessive slip occurs.
- 3. A signaling system as described in claim 1, wherein the transducer lacks moving parts and is selected from the group consisting of a piezoelectric transducer, a GPS receiver and a conductive electrode measurement system.
- 4. A signaling system as described in claim 1, further comprising an electrical connection to a controller of the motor suitable for decreasing motor power in high slip conditions.
- 5. A signaling system as described in claim 1, wherein the signal display is selected from the group consisting of an analog meter with a display surface having at least two colored areas denoting acceptable efficiency and less optimum efficiency; an analog meter with a display surface having green, yellow and red lights or colored areas that respectively indicate acceptable, less acceptable and least acceptable efficiency, respectively; a display surface having multiple light emiting diodes denoting at least an acceptable efficiency and a less acceptable efficiency; a buzzer that sounds when efficiency drops below a set threshold value; a piezo sounding device that emits sound when efficiency drops below a set threshold value; and a chime that indicates when efficiency drops below a set threshold value.
- 6. A visual display for continuously indicating motor driven boat propeller efficiency comprising:
(a) a first electrical signal proportional to boat speed; (b) a second electrical signal proportional to propeller speed; (c) a circuit that accepts the first electrical signal proportional to boat speed and the second electrical signal proportional to propeller speed and compares the two signals to generate a slip measurement that is output; and (d) a signal display that accepts the output measurement selected from the group consisting of an analog meter with a display surface having at least two colored areas denoting acceptable efficiency and less optimum efficiency; an analog meter with a display surface having green, yellow and red lights or colored areas that respectively indicate acceptable, less acceptable and least acceptable efficiency, an analog meter having a display surface with at least 3 regions located from left to right as indicating negative slip (deceleration), acceptable slip and excessive slip (or cavitation) respectively respectively; a display surface having multiple light emitting diodes denoting at least an acceptable efficiency and a less acceptable efficiency; and a liquid crystal display, wherein a greater acceptable slip at lower speed is factored into the comparison by the circuit of (c) or is accommodated by the display to indicate acceptable slip.
- 7. A visual display system as described in claim 6, wherein the first electrical signal proportional to boat speed is selected from the group consisting of: an electrical signal proportionate to motor current; an electrical signal proportionate to motor power; and an electrical signal generated by a boat speed transducer.
- 8. A visual display system as described in claim 6, wherein the circuit compensates for a lower desirable slip at higher boat speeds by electrically subtracting a signal corresponding to boat speed from a signal corresponding to a derived slip measurement before outputting the compensated result.
- 9. A visual display system as described in claim 6, wherein the second electrical signal is motor voltage.
- 10. A visual display of boat propeller efficiency as described in claim 6, wherein the circuit of (c) converts an analog signal of (a) to logarithmic form, converts an analog signal of (b) to logarithmic form and then compares the two logarithmic signals to obtain an output signal corresponding to propeller efficiency.
- 11. A visual display of boat propeller efficiency as described in claim 6, wherein the circuit of (c) comprises a computer.
- 12. A cavitation indication device for an electric motor driven watercraft comprising:
(a) an electrical signal proportional to motor power, electric motor current, and/or boat speed; (b) a circuit that accepts the electrical signal and a signal proportional to propeller speed and that outputs a cavitation signal; (c) a visual or audible readout signaler that receives the output signal from the circuit and indicates the presence of cavitation.
- 13. A cavitation indication device as described in claim 13, further comprising an electrical connection to a controller of the electric motor suitable for decreasing engine power.
- 14. A cavitation indication device as described in claim 13, further comprising a boat speed sensor selected from the group consisting of a piezoelectric sensor and an electrode pair.
- 15. A cavitation indicator for a motor driven watercraft, the indicator capable of detecting low speed acceleration cavitation separate from cavitation occurring at hull speed or at planing speed, comprising:
(a) a transducer or motor voltage input for generating an electrical signal proportional to propeller rpm; (b) a reference electric signal that is proportional to at least motor power, motor current or boat speed; (c) a comparator that receives signals from (a) and (b) wherein the comparator uses the signals from (a) and (b) to separately detect low speed acceleration cavitation, no cavitation and high speed cavitation conditions; and (d) an output device.
- 16. A cavitation indicator as described in claim 15, wherein the output device is selected from the group consisting of an analog panel meter, a bell, a piezo transducer, a light emitting diode, light emitting diodes, a liquid crystal display and a chime.
- 17. A cavitation indicator as described in claim 15, wherein the output device further is used to control the watercraft motor, to alleviate cavitation upon detection of the cavitation by decreasing motor speed.
- 18. A cavitation indicator as described in claim 15, further comprising a piezoelectric transducer in contact with water that generates the reference electrical signal of (b) proportional to boat speed.
- 19. A device that can detect an anchor down, propeller up or other unusual situation of a motor driven watercraft comprising:
(a) an electrical signal proportional to propeller rpm; (b) a reference electric signal that is proportional to motor power, motor current and/or boat speed; (c) a comparator that receives signals from (a) and (b) and outputs an anomalous propeller loading signal upon detecting a high slip condition at low propeller speed and low boat speed; and (d) a signaling device that alerts the boat operator.
- 20. A device as described in claim 19, wherein reference electrical signal of (b) is generated by a piezoelectric device or electrode pair in contact with the water.
REFERENCE TO RELATED APPLICATIONS
[0001] This application receives priority from U.S. 60/296,754.
Provisional Applications (1)
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Number |
Date |
Country |
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60296754 |
Jun 2001 |
US |