Patent Application
20240391575
The present invention relates broadly, but not exclusively, to a propulsion module for a watercraft, a propulsion system for the watercraft, the watercraft, and assembly methods thereof.
Electric motorized watercrafts including personal watercrafts such as jetboards, and specialized marine crafts can be used in recreational, commercial and military applications. A typical electric motorized watercraft comprises a hull, a power system for propelling the electric motorized watercraft on seawater and a controller system for controlling the power system.
In the typical electric motorized watercraft, a pin-socket type connection between the power system and the controller system may be used. While the pin-socket type connection may be designed to be watertight, due to high and variable currents through the pins and the sockets during a typical use of the electric motorized watercraft, there can be thermal expansion and contraction of the metal pins and the metal sockets. This can lead to creeping of moisture, in particular seawater, in between the contact surfaces of the pins and the sockets, resulting in a build-up of salts over time, which can corrode the pins and/or the sockets. Corrosion of the pins and/or the sockets can cause substantial water ingress into the connections, thereby leading to an electrical short circuit.
Further, high heat may be generated in wires connecting the power system and the controller system. The high heat can affect rubber seals used in cable glands for the wires. Specifically, the high heat may cause the rubber seals to harden and crack over time due to varying temperatures between the high heat and the seawater temperature, especially when the electric motorized watercraft is used in colder waters. The hardened and cracked rubber seals can lead to water ingress through the cable glands over time, thereby resulting in an electrical short circuit.
In addition, the power system and the controller system of the electric motorized watercraft can generate a large amount of heat that needs to be quickly dissipated. A conventional method of cooling requires seawater to be internally circulated in the power system and the controller system. The conventional cooling method may be prone to blockage due to debris and salt deposits, leading to overheating of the power system and the controller system, which may in turn result in failure of the power system and the controller system.
Also, a battery of the power system needs to be waterproof and safe to users when it is detached from the electric motorized watercraft. A conventional battery has battery power terminals which can be switched on live via a push button even when the battery is detached from the electric motorized watercraft. This can expose the users to electric shocks. Further, the detached battery can short circuit if the battery power terminals are accidentally electrically connected, for example when there is water across the battery power terminals or accidental contact of both terminals.
A need therefore exists to provide an electric motorized watercraft that seeks to address at least some of the above problems. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background of the disclosure.
According to a first aspect, there is provided a propulsion module for a watercraft, comprising: a waterjet; an electric motor configured to channel seawater through the waterjet, wherein in use, the electric motor is configured to be externally passively cooled by surrounding seawater; and an electronic speed controller (ESC) connected to the electric motor and configured to control the electric motor, wherein in use, the ESC is configured to be externally passively cooled by the surrounding seawater.
According to a second aspect, there is provided a propulsion system for a watercraft, comprising: a propulsion module, wherein the propulsion module comprises: a waterjet; an electric motor configured to channel seawater through the waterjet, wherein in use, the electric motor is configured to be externally passively cooled by surrounding seawater; and an electronic speed controller (ESC) connected to the electric motor and configured to control the electric motor, wherein in use, the ESC is configured to be externally passively cooled by the surrounding seawater; and a power module detachably attachable to the propulsion module, wherein the power module is configured to provide electricity to the propulsion module.
According to a third aspect, there is provided a watercraft, comprising: a hull module; a propulsion module detachably attachable to the hull module, wherein the propulsion module comprises: a waterjet; an electric motor configured to channel seawater through the waterjet, wherein in use, the electric motor is configured to be externally passively cooled by surrounding seawater; and an electronic speed controller (ESC) connected to the electric motor and configured to control the electric motor, wherein in use, the ESC is configured to be externally passively cooled by the surrounding seawater; and a power module detachably attachable to the propulsion module, wherein the power module is configured to provide electricity to the propulsion module.
According to a fourth aspect, there is provided an assembly method for a propulsion module for a watercraft, comprising: providing a waterjet; providing an electric motor configured to channel seawater through the waterjet, wherein in use, the electric motor is configured to be externally passively cooled by surrounding seawater; attaching the electric motor to the waterjet; providing an electronic speed controller (ESC) configured to control the electric motor, wherein in use, the ESC is configured to be externally passively cooled by the surrounding seawater; and connecting the ESC to the electric motor.
According to a fifth aspect, there is provided an assembly method for a propulsion system for a watercraft, comprising: providing a propulsion module, wherein the propulsion module comprises: a waterjet; an electric motor configured to channel seawater through the waterjet, wherein in use, the electric motor is configured to be externally passively cooled by surrounding seawater; and an electronic speed controller (ESC) connected to the electric motor and configured to control the electric motor, wherein in use, the ESC is configured to be externally passively cooled by the surrounding seawater; and attaching a power module to the propulsion module, wherein the power module is configured to provide electricity to the propulsion module.
According to a sixth aspect, there is provided an assembly method for a watercraft, comprising: providing a hull module; attaching a propulsion module to the hull module, wherein the propulsion module comprises: a waterjet; an electric motor configured to channel seawater through the waterjet, wherein in use, the electric motor is configured to be externally passively cooled by surrounding seawater; and an electronic speed controller (ESC) connected to the electric motor and configured to control the electric motor, wherein in use, the ESC is configured to be externally passively cooled by the surrounding seawater; and attaching a power module to the propulsion module, wherein the power module is configured to provide electricity to the propulsion module.
Embodiments and implementations are provided by way of example only, and will be better understood and readily apparent to one of ordinary skill in the art from the following written description, read in conjunction with the drawings, in which:
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been depicted to scale.
Embodiments will be described, by way of example only, with reference to the drawings. Like reference numerals and characters in the drawings refer to like elements or equivalents.
Embodiments of the invention provide a propulsion module for a watercraft, a propulsion system for the watercraft and the watercraft. Advantageously, the watercraft allows a user to move over water surface under the watercraft's power, without external power assistance such as from wind, waves or the user. As would be appreciated, the watercraft can be an electric motorized watercraft including a personal watercraft such as a jetboard, and a specialized marine craft. The watercraft can be used in various applications such as recreational, commercial and military applications. As non-limiting examples, embodiments of the invention can be used in an inflatable monohull, a twin-hull boat, and/or a submerged underwater diver delivery vehicle.
According to one embodiment, the electric motor 104 may be a brushless direct current (BLDC) sensored motor. In some implementations, the electric motor 104 may be a BLDC sensored motor with field-weakening. The electric motor 104 may comprise a hollow member disposed along a rotational axis of a rotor of the electric motor 104. In use, the electric motor 104 may be configured to be further passively cooled by the surrounding seawater channeled through the hollow member by a centrifugal force created by the electric motor 104. The hollow member may be a hollow shaft.
Further, the ESC may comprise electrical components housed in an ESC casing 106. The electrical components may be in thermal contact with an inner surface of the ESC casing 106. The ESC casing 106 may be made of a metallic material such as aluminium. The ESC casing 106 may also be configured to be fully watertight. The external surfaces of the ESC casing 106 can be exposed to the surrounding seawater and the bottom of the ESC casing 106 may be in direct contact with seawater flowing under the bottom of the watercraft. In some implementations, the bottom of the ESC casing 106 may form part of the bottom of the watercraft. Beneficially, the arrangement allows the ESC casing 106 to be exposed to a relatively high flow of seawater to rapidly dissipate heat generated by the electrical components in the ESC. One or more external surfaces of the ESC casing 106 may be roughened to optimize a boundary layer behaviour to allow maximum inflow into a water intake member 108 and the waterjet 102. An intake to the waterjet 102 may be part of a monocoque design that integrates the structure of the propulsion module 100 into a single water intake member 108. The water intake member 108 can be made of carbon fibre. The water intake member 108 can be moulded to a predefined shape based on requirements to ensure optimum water inflow into the waterjet 102 for improved performance.
The assembly of the electric motor 104 and the waterjet 102 into the propulsion module 100 can be done using non-metallic materials such as Acrylonitrile Butadiene Styrene (ABS) plastic. Beneficially, possible galvanic corrosion between stainless steel screws, carbon fibre and threaded aluminium plates in a typical watercraft can be prevented. As a result, life of mechanical connections is improved because corrosion in threads holding the stainless steel screws is eliminated. Similarly, a mounting interface 110 of the propulsion module 100 can also be made of ABS plastic so as to isolate stainless steel fasteners from other metallic material. Beneficially, galvanic corrosion is prevented. The mounting interface 110 can have a dovetail design. Beneficially, the dovetail design allows for a quick slide-and-screw installation of the propulsion module 100 to the watercraft, while allowing high transfer of thrust from the propulsion module 100 into the watercraft.
Further, the propulsion module 100 may comprise a water intake grating 112 configured to restrict floating debris from entering the propulsion module 100 and also protect the user from accidental contact with moving parts of the waterjet 102. The water intake grating 112 may have a streamlined profile and may be configured to withstand impact from the floating debris. The water intake grating 112 may also have a winged profile for improving water inflow into the waterjet 102 at high speeds in both strong waves and calm water conditions, with minimal additional drag.
According to some implementations, the propulsion module 100 may further comprise a connecting member 114 attached to the ESC and the electric motor 104. The connecting member 114 may be watertight and may house wires connecting the ESC and the electric motor 104. The connecting member 114 may be a rigid structure and may be made of a metallic material such as aluminium. Further, the connecting member 114 may be threaded at both ends and may form a watertight seal when fixed to the electric motor 104 and the ESC with a high temperature-resistant silicon gasket. The wires connecting the ESC and the electric motor 104 may comprise electric motor power wires and sensor wires. Beneficially, the wires connecting the ESC and the electric motor 104 are protected from possible damage and are not in contact with the seawater, thereby reduces the possibility of a short circuit. In some implementations, the propulsion module 100 may comprise a plurality of connecting members 114 attached to the ESC and the electric motor 104. Each motor phase wire may pass through a separate connecting member 114. Advantageously, the arrangement allows improved dissipation of heat generated by the wires, without significant expansion or contraction of the connecting members 114. The possibility of water ingress into the electric motor 104 and/or the ESC is eliminated, thus preventing a short circuit due to water ingress. Further, the connecting members 114 also enhances ease and speed of assembling the propulsion module 100 as the electric motor 104 can be pre-assembled with the ESC into a single unit.
According to an example embodiment, a propulsion system for a watercraft comprises a propulsion module 100. The propulsion module 100 comprises a waterjet 102. The propulsion module 100 also comprises an electric motor 104 configured to channel seawater through the waterjet 102. In use, the electric motor 104 is configured to be externally passively cooled by surrounding seawater. Further, the propulsion module 100 comprises an electronic speed controller (ESC) connected to the electric motor 104 and configured to control the electric motor 104. In use, the ESC is configured to be externally passively cooled by the surrounding seawater. The propulsion system also comprises a power module detachably attachable to the propulsion module 100. The power module is configured to provide electricity to the propulsion module 100.
The power module 200 may comprise a first sensor 204 configured to detect that the power module 200 is attached to the propulsion module 100. The power module 200 may further comprise a second sensor 206 configured to detect that an external kill switch is attached to the power module 200. The first sensor 204 and the second sensor 206 may be hall sensors. According to one embodiment, a main power switch on a power management system may be closed and the power module 200 may only be live to deliver electrical power to the ESC only when the first sensor 204 detects that the power module 200 is attached to the propulsion module 100, and the second sensor 206 detects that an external kill switch is attached to the power module 200. Beneficially, safety of using the watercraft is enhanced. For example, once the user falls off a moving watercraft, electrical power to the watercraft would automatically be cut off.
In some implementations, the second sensor 206 may be disposed at the first endcap 203. Further, the power module 200 may comprise a plurality of first sensors 204 and/or second sensors 206. The power module 200 may also comprise a power level indicator 207 and a safety control board.
As mentioned above, the power module 200 can comprise a battery. The battery can be a Li-NMC cylindrical cell pack configured to withstand high operating temperatures. Further, a battery management system (BMS) can be provided for additional safety with multiple alarms and shut off levels.
When the power module 200 is locked in place in the watercraft, a socket of the power module 200 is fully engaged with power and/or communications pins of the watercraft. Removal of the power module 200 may require lifting the power module 200 while overcoming a frictional force between the pins and the socket. The removal of the power module 200 may be relatively easy to perform when the watercraft is new and the pins are clean. However, over time, exposure of the pins to marine environments, for example seawater, can cause surfaces of the pins to develop a layer of oxide. The layer of oxide can increase a frictional force between the pins and the socket, resulting in a need for a relatively greater force to remove the power module 200 from the watercraft.
The power module 200 may comprise a cam 208 attached to a handle 210 of the power module 200. In use, the cam 208 can push the power module 200 in a direction away from the propulsion module 100. Beneficially, the cam 208 provides improved ease when disengaging and detaching the power module 200 from the propulsion module 100 and removing the power module 200 from the watercraft. Safety of the user is also enhanced as the need to fit fingertips into small gaps to pry the power module 200 out of the watercraft is eliminated, hence preventing risk of the fingers being pinched.
The hull module 300 may be designed to be hydrodynamically stable and agile for different user weights and different speeds of the watercraft 400. Bottom and sides of the hull module 300 may be shaped based on Computational Fluid Dynamics (CFD) analysis of computer models and/or full-scale real-life testing of prototypes. Beneficially, good balance and minimal roll at low speeds, and excellent manoeuvring at high speeds is achieved. The hull module 300 may be constructed by precision moulding layers of glass and carbon fibres over a moulded Expanded Polystyrene (EPS) foam core and thermoformed shapes that resemble shapes of the propulsion module 100 and the power module 200 to form cavities therein.
As shown in
A structure formed in the hull module 300 that defines the second cavity 304 may include wedges along its edges. Beneficially, the wedges act as a guide for the power module 200 such that the power module 200 can be self-centered while being inserted into the second cavity 304 and locked in place.
The propulsion module 100 can be designed for relatively simple installation of its components such as the electric motor 104 and allows waterflow to be directed to required parts of the propulsion module 100 and the power module 200 to ensure adequate external passive cooling of the propulsion module 100 and power module 200 by the seawater. The watercraft 400 may have gaps between the hull module 300 and the propulsion module 100. Advantageously, the gaps permit adequate amount of seawater to circulate past the electric motor 104 and the power module 200 to remove heat generated during operation. The gaps can also draw air bubbles trapped under the bottom of the watercraft 400, away from the waterjet 102, thereby increasing efficiency of the waterjet 102.
Referring to
Referring to
Further, the hull module 300 may have one or more foot binding inserts formed in the deck pad 308. The power module 200 may also have one or more foot binding inserts formed therein. Foot bindings can be fixed to the foot binding inserts using screws or any other fixing means. The user can slip each foot into a respective foot binding to maintain full contact with the watercraft while riding. Beneficially, enhanced control is provided to the user. In addition, the one or more foot binding inserts of the power module 200 may be disposed at the handle 210 of the power module 200 (see
Referring to
As shown in
The watercraft 400 may further comprise a controller module. The controller module may comprise a wireless controller configured to transmit a signal to the ESC based on a user preference. As a non-limiting example, the user preference can comprise a speed level. In some implementations, the controller module may be configured to indicate a connection status between the controller module and the power module 200. Further, the controller module may indicate a remaining battery level of the wireless controller and/or the power module 200. The controller module may also comprise a wired receiver connected to the ESC. In some implementations, the controller module may be disposed in the propulsion system.
As mentioned above, the receiver 502 can be embedded in the front binder 500. The receiver 502 can be radiolucent. In some implementations, the receiver 502 can be disposed at a distance away from the propulsion module 100 and power module 200 to minimize electromagnetic interference (EMI), which may interfere with radio signals. The receiver 502 may have amplified sensors to maintain radio link with the wireless controller even when the watercraft 400 is momentarily underwater and also to overcome any stray EMI.
A receiver cable may pass through a receiver cable tunnel that can be disposed adjacent to the power module 200. Beneficially, the receiver cable tunnel provides separation of the receiver 502 from potential EMI from the power module 200. A water-tight receiver connector may be disposed at the ESC. Advantageously, the receiver connector allows for easy replacement of the front binder 500 and/or the propulsion module 100.
The wireless controller can be configured to provide the user of any skill level an ability to control a power level of the watercraft 400 precisely to match his/her skill level, while incorporating necessary safety features. The wireless controller may be waterproof. Further, the wireless controller may comprise a built-in battery which can be charged via a watertight magnetic connector. The wireless controller can be used to control a throttle via a finger trigger, and can comprise two thumb buttons for increasing and/or decreasing the power level of the watercraft 400. The user can increase and/or decrease the power level of the watercraft 400 in small fixed increments, while on the move, without a need for mobile applications to change watercraft power settings. The graduated sensitivity of the throttle beneficially allows the user to finely adjust a throttle between power levels of the watercraft 400.
The wireless controller can also display a remaining power in the battery via a LED indicator. The LED indicator may change lights according to a remaining power in the battery. For example, green may indicate full battery level, orange may indicate medium battery level, and red may indicate low battery level. An LCD display may be provided to show the battery levels of the wireless controller and/or the watercraft 400 in clear and simple bars. The LCD display may also show the power level of the watercraft 400 and locked and/or unlocked status of the power module 200 in the watercraft 400. A solid, non-flashing light indicated on the wireless controller may show that the wireless controller is connected to the watercraft 400 and is ready for use.
It will be appreciated by a person skilled in the art that numerous variations and/or modifications may be made to the present invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. For example, parameters such as shape of the hull module may vary depending on the application for optimizing performance. The present embodiments are, therefore, to be considered in all respects to be illustrative and not restrictive.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10202301498U | May 2023 | SG | national |
