WATERCRAFT

Abstract

A watercraft including a hull; a deck; a propulsion system to propel the watercraft; an electric motor to drive the propulsion system; a battery; and at least one heat exchanger at least partially extending out of the hull such that at least a portion of the heat exchanger is in contact with the body of water, a first cooling circuit in thermal communication with the heat exchanger and at least one of the battery and the electric motor, the first cooling circuit being configured to circulate a heat exchange fluid therein, a second cooling circuit being in thermal communication with an other one of the at least one of the electric motor and the battery, the second cooling circuit being in fluid communication with the body of water during operation of the watercraft for circulating water from the body of water in the second cooling circuit during use.

Description

FIELD OF TECHNOLOGY

The present technology relates to systems for thermal management in watercraft.

BACKGROUND

The electrification of vehicles is becoming more commonplace in today's market in an effort to offer consumers vehicular options that minimize emissions. For instance, battery-powered watercraft (i.e., electric watercraft) such as personal watercraft (PWC) are now available to consumers that desire an emissions-free watercraft. However, electric watercraft also face different challenges.

The thermal limitations of electric components in an electric watercraft powertrain can vary significantly. Batteries, motors, and various electrical and electronic components can have different working temperatures, with each needing to be managed in order to produce an efficient vehicle performance and component lifetime. While watercraft often take advantage of the body of water in which they operate for cooling, this can be more complicated for electronics and especially in saltwater environments.

In view of the foregoing, there is a need for an electric watercraft which addresses at least in part some of these defects.

SUMMARY

It is an object of the present technology to ameliorate at least some of the inconveniences present in the prior art.

According to aspects of the present technology, there is provided an electric watercraft with two cooling circuits, or cooling loops, for providing thermal management of different electronic components. The present technology includes a closed cooling loop, where heat exchange fluid is circulated and sealed therein, for cooling the battery or the motor. The electric watercraft also has an open cooling loop, where water from the body water in which the watercraft is operated is circulated through the loop and back into the body of water. The open cooling loop provides cooling to the other one of the battery or motor. In some embodiments, the battery, as well as other electronic components such as the inverter and the charger, are cooled using the closed loop. In some cases, use of a closed cooling loop to provide thermal management to at least certain components can reduce long term wear and tear and/or maintenance costs compared to open cooling loops, as there is no possibility of debris or salt intrusion in the closed cooling loop.

Vehicle propulsion batteries generally have an optimal and maximal working temperature of around 20° C. and 60° C. respectively, while electric motors generally have optimal and maximal working temperatures of around 30° C. and 170° C. respectively. The higher working temperature of the motor could thus prevent a single cooling loop from properly controlling the temperature of both the motor and the battery. By the present technology, the motor, having a higher maximal working temperature, is removed from the battery's coolant circuit's thermal load. An improved thermal, and vehicle, performance can thus be achieved. In some embodiments, the open cooling loop specifically cools the motor, thereby utilizing the relatively large heat sink of a body of water to thermally manage the motor.

According to aspects of the present technology, there is provided a watercraft for operating on a body of water, the watercraft including a hull; the deck supported by the hull; a propulsion system supported by the hull and configured to propel the watercraft; an electric motor operatively connected to the propulsion system to drive the propulsion system; a battery electrically connected to the electric motor for powering the electric motor; and at least one heat exchanger supported by the hull, the at least one heat exchanger at least partially extending out of the hull such that at least a portion of the at least one heat exchanger is in contact with the body of water, a first cooling circuit being in thermal communication with the at least one heat exchanger and at least one of the battery and the electric motor, the first cooling circuit being configured to circulate a heat exchange fluid therein, a second cooling circuit being in thermal communication with an other one of the at least one of the electric motor and the battery, the second cooling circuit being in fluid communication with the body of water during operation of the watercraft for circulating water from the body of water in the second cooling circuit during use.

In some embodiments, the watercraft further includes a charger electrically connected to the battery; and an inverter electrically connected to the battery.

In some embodiments, the first cooling circuit is further in thermal communication with at least one of the charger and the inverter.

In some embodiments, the first cooling circuit is arranged to transfer, when in operation, heat from the at least one of the battery and the electric motor and the at least one of the charger and inverter to the body of water via the at least one heat exchanger; and the second cooling circuit is arranged to transfer, when in operation, heat from the other one of the battery and the electric motor to the body of water.

In some embodiments, the at least one of the battery and the electric motor is the battery, the first cooling circuit being in thermal communication with the battery; and the other one of the battery and the electric motor is the electric motor, the second cooling circuit being in thermal communication with the electric motor.

In some embodiments, the second cooling circuit is further in thermal communication with at least one of the charger and the inverter.

In some embodiments, the first cooling circuit is arranged to transfer, when in operation, heat from the one of the battery and the electric motor to the body of water via the at least one heat exchanger; and the second cooling circuit is arranged to transfer, when in operation, heat from the other one of the battery and the electric motor and the at least one of the charger and inverter to the body of water.

In some embodiments, the watercraft further includes a first pump forming a portion of the first cooling circuit, the first pump being arranged to cause the heat exchange fluid to circulate through the first cooling circuit.

In some embodiments, the watercraft further includes a second pump forming a portion of the second cooling circuit, the second pump being arranged to cause water from the body of water to circulate through the second cooling circuit.

In some embodiments, the second pump forms a portion of the propulsion system.

In some embodiments, the battery, the charger, and the inverter are isolated from the body of water.

In some embodiments, the first cooling circuit is a closed cooling loop; and the second cooling circuit is an open cooling loop.

In some embodiments, the watercraft further includes a straddle seat supported by the deck; and the watercraft is a personal watercraft.

For purposes of this application, the terms related to spatial orientation such as forwardly, rearward, left and right, are as they would normally be understood by a driver of a vehicle sitting thereon in a normal driving position.

Embodiments of the present technology each have at least one of the above-mentioned objects and/or aspects, but do not necessarily have all of them. It should be understood that some aspects of the present technology that have resulted from attempting to attain the above-mentioned objects may not satisfy these objects and/or may satisfy other objects not specifically recited herein.

Additional and/or alternative features, aspects, and advantages of embodiments of the present technology will become apparent from the following description, the accompanying drawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present technology, as well as other aspects and further features thereof, reference is made to the following description which is to be used in conjunction with the accompanying drawings, where:

FIG. 1 is a right side elevation view of an electric personal watercraft in accordance with an embodiment of the present technology;

FIG. 2 is a top plan view of the watercraft of FIG. 1;

FIG. 3 is a bottom plan view of the watercraft of FIG. 1;

FIG. 4 is a top, rear, right side perspective view of the watercraft of FIG. 1, with upper portions of the watercraft having been removed;

FIG. 5 is a bottom, rear, right side perspective view of the portions of the watercraft of FIG. 4;

FIG. 6 is a top plan view of the portions of the watercraft of FIG. 4;

FIG. 7 is a top, front, left side perspective view of a power system of the watercraft of FIG. 1;

FIG. 8 is a top, front, right side perspective view of the power system of FIG. 7, with a closed cooling circuit illustrated schematically;

FIG. 9 is a top, rear, left side perspective view of rear portions of the power system of FIG. 7, with an open cooling circuit illustrated schematically;

FIG. 10 is a top, front, left side perspective view of the rear portions of the power system of FIG. 9, with the open cooling circuit illustrated schematically;

FIG. 11 is a schematic diagram of cooling systems of the watercraft of FIG. 1;

FIG. 12 is a schematic diagram of cooling systems of another embodiment of a watercraft according to the present technology; and

FIG. 13 is a schematic diagram of cooling systems of yet another embodiment of a watercraft according to the present technology.

DETAILED DESCRIPTION

An electric watercraft 10 in accordance with one embodiment of the present technology is shown in FIGS. 1 to 3. In this embodiment, the electric watercraft 10 is an electric personal watercraft (PWC) 10 (i.e., wherein the motive power is electric). Those of ordinary skill in the art will recognize that other types of electric watercraft, for example a hybrid electric and mechanical motive power vehicle could also implement the present technology.

The PWC 10 has a hull 12 and a deck 14 supported by the hull 12. The hull 12 buoyantly supports the PWC 10 in the water. The hull 12 defines a bow 42 and a stern 44 opposite the bow 42, as well as a laterally centered keel 45 (FIG. 3). The deck 14 is designed to accommodate one or multiple riders. The hull 12 and the deck 14 are joined together at a seam 16 that joins the parts in a sealing relationship. A bumper 18 generally covers the seam 16, which helps to prevent damage to the outer surface of the PWC 10 when the PWC 10 is docked, for example.

As shown in FIG. 1, the deck 14 has a centrally positioned straddle-type seat 28 positioned on top of a pedestal 30 to accommodate multiple riders in a straddling position. The seat 28 includes a front seat portion 32 and a rear, raised seat portion 34. The seat 28 is preferably made as a cushioned or padded unit, or as interfitting units. The front and rear seat portions 32, 34 are removably attached to the pedestal 30.

The PWC 10 has a pair of generally upwardly extending walls located on either side of the PWC 10 known as gunwales or gunnels 36. The gunnels 36 help to prevent the entry of water in the footrests 38 of the PWC 10, provide lateral support for the riders' feet, and also provide buoyancy when turning the PWC 10, since the PWC 10 may roll slightly when turning.

Located on both sides of the PWC 10, between the pedestal 30 and the gunnels 36, are the footrests 38 (FIG. 2). The footrests 38 are designed to accommodate the riders' feet in various riding positions. The footrests 38 are covered by carpeting made of a rubber-type material, for example, to provide additional comfort and traction for the feet of the riders. A reboarding platform 40 is provided at the rear of the PWC 10 on the deck 14 to allow the rider or a passenger to easily reboard the PWC 10 from the water. Nonslip mats or some other suitable covering may cover the reboarding platform 40.

As shown in FIG. 1, the PWC 10 is provided with a hood 46 located forwardly of the seat 28 and a helm assembly 60. Rear-view mirrors 62 are positioned on either side of the hood 46 to allow the rider to see behind the PWC 10.

As best seen in FIG. 2, the helm assembly 60 is positioned forwardly of the seat 28. The helm assembly 60 has a central helm portion 64, that is padded, and a pair of steering handles 65, also referred to as a handlebar. One of the steering handles 65 is provided with an acceleration actuator (not shown), which allows the rider to control an electric motor 22 (described below), and therefore the speed of the PWC 10. The acceleration actuator is a finger-actuated actuator, but it is contemplated that the acceleration actuator could be a thumb-actuated lever or a twist grip. The other of the steering handles 65 is provided with a reverse gate operator (not shown) used by the driver to actuate a reverse gate (not shown) of the PWC 10. The reverse gate operator is a finger-actuated lever, but it is contemplated that the reverse gate operator could be a thumb-actuated lever or a twist grip.

With additional reference to FIGS. 4 to 8, a jet propulsion system 50 (also commonly referred to as a “jet pump drive”) and power components, including the motor 22, are supported by the hull 12 and enclosed between the hull 12 and the deck 14. The power components provided power to the motor 22 to drive the jet propulsion system 50; the power components are described in more detail below.

The PWC 10 is propelled by the jet propulsion system 50 which pressurizes water to create thrust. To that end, the jet propulsion system 50 has a duct 52 (FIG. 5) in which water is pressurized and which is defined by various components of the jet propulsion system 50, including a ride plate 73, an impeller housing 51, and a steering nozzle 57 of the jet propulsion system 50. A driveshaft 55 is connected between the electric motor 22 and an impeller 70 of the jet propulsion system 50. A bellow assembly 56 is mounted to the driveshaft 55 and provides a seal between the duct 52 and the hull 12 such as to prevent entry of water into the hull.

As best shown in FIG. 5, the duct 52 has an inlet 86 positioned under the hull 12. When the jet propulsion system 50 is in operation, water is first scooped into an inlet 86. An inlet grate 53 (FIG. 3) is positioned adjacent (i.e., at or near to) the inlet 86 and is configured to prevent large rocks, weeds, and other debris from entering the jet propulsion system 50, which may damage the system or negatively affect performance. It is contemplated that the inlet grate could be positioned in the inlet 86.

With continued reference to FIGS. 4 to 8, the PWC 10 includes a battery 105 in electrical communication with electric motor 22 which stores electrical power for powering the electric motor 22. To manage and charge the battery 105, the PWC 10 also includes a charger 110 electrically connected to the battery 105 and an inverter 112 electrically connected to the battery 105. Additional components of the power system of the electric PWC 10, including but not limited to electrical control units and wiring/cabling, could be included but specific details depend on the particular embodiment.

According to the present technology and illustrated in FIGS. 8 to 11, the PWC 10 includes two cooling circuits, also referred to as cooling loops, for providing thermal management of the electrical components of the PWC 10. In order to respect significantly different thermal limits and manage multiple heat generation profiles across the different electrical components, the battery 105 and the electric motor 22 are cooled by separate cooling circuits.

The PWC 10 includes a first cooling circuit 140 configured to circulate a heat exchange fluid therein, illustrated in FIGS. 8 and 11. The cooling circuit 140 is specifically a closed loop, where the heat exchange fluid circulates within a closed volume and is maintained therein. The choice of heat exchange fluid is not meant to be specifically limiting, and could include, but is not limited to, ethylene glycol, propylene glycol, and mixtures thereof with water.

The cooling circuit 140 includes a variety of tubes and channels for bringing the heat exchange fluid into thermal communication with the electrical components thermally managed by the cooling circuit 140 (described further below). The particular arrangement for fluid flow will depend on the specific embodiment, and thus tubing and channels have been omitted or shown schematically for simplicity. In order to cause the heat exchange fluid to circulate through the cooling circuit 140, the PWC 10 includes a pump 145 (shown schematically) forming a portion of the cooling circuit 140 and being arranged to cause the heat exchange fluid to circulate through the cooling circuit 140.

In order to transfer heat from the heat exchange fluid to the environment, the watercraft 10 also includes a heat exchanger supported by the hull 12. In the present embodiment, the heat exchanger is specifically the ride plate 73. The ride plate 73 has a heat exchange channel 75 defined therein (shown schematically, FIG. 8) through which the heat exchange fluid flows when in operation. The heat exchanger 73 partially extends out of the hull 12, such that a portion of the heat exchanger 73 is in contact with the body of water in which the watercraft 10 is operating. The heat exchanger 73 can thus conduct heat out of the heat exchange fluid and into the body of water. It is contemplated, however, that a separate and/or additional heat exchanger could be used in some embodiments.

The cooling circuit 140 is arranged to provide thermal management, generally cooling, to some of the electric components of the PWC 10. Specifically, the cooling circuit 140 is in thermal communication with the battery 105. A housing 106 of the battery 105 includes a thermal exchange channel 107 (shown schematically) forming a portion of the cooling circuit 140 and receiving heat exchange fluid therethrough. Different arrangements for providing thermal communication between the heat exchange fluid and the battery 105 are also contemplated.

In the present embodiment, the cooling circuit 140 is further in thermal communication with the charger 110 and the inverter 112. The housings of each of the charger 110 and the inverter 112 include heat exchange channels (not shown), but the particular arrangement is not meant to be particularly limiting. It is contemplated that additional components of the PWC 10 could be in thermal communication with the cooling circuit 140.

With continued reference to FIGS. 9 to 11, the watercraft 10 further includes a second cooling circuit 160, also referred to as the cooling loop 160. The cooling circuit 160 is in fluid communication with the body of water during operation of the watercraft, such that water from the body of water circulates in the cooling circuit 160. The cooling circuit 160 is thus an open cooling loop, where water from the body of water flows into, through, and out of the cooling circuit 160, without any recirculation of the water. The particular arrangement for fluid flow through the PWC 10 will depend on the specific embodiment, and thus tubing and channels have been omitted or shown schematically for simplicity. In order to cause water from the body of water to circulate through the cooling circuit 160, the PWC 10 includes a pump 165 (shown schematically, FIG. 8) forming a portion of the cooling circuit 160 and being arranged to cause water to circulate through the cooling circuit 160. In the present embodiment, the pump 165 forms a portion of the propulsion system 50, the housing 51 being in fluid communication with the cooling circuit 160. As the propulsion system 50 pressurizes water flow therethrough for providing vehicle motive power, it also acts as the pump 165 of the cooling circuit 160.

With additional reference to FIGS. 9 and 10, the cooling circuit 160 is in thermal communication with the electric motor 22. The motor 22 includes a cooling jacket 23 which defines therein a heat exchange channel 24. The channel 24 defines a portion of the cooling circuit 160 and through which water flows when in operation. When the motor 22 is thermally connected to a closed cooling loop (see embodiments below), the cooling jacket 23 could be configured to receive heat exchange fluid therethrough. Specifically, in the present embodiment water from the body of water is pressurized by the propulsion system 50 and thus forced into and through the cooling jacket 23.

Different arrangements for thermal communication between the cooling circuit 160 and the motor 22 are contemplated. It is also contemplated that the cooling circuit 160 could be in thermal communication with the charger 110, the inverter 112, and/or other components of the PWC 10 in some embodiments.

The cooling circuit 140 is thus arranged to transfer, when in operation, heat from the battery 105, the charger 110, and the inverter 112 to the body of water via the heat exchanger 73, and the cooling circuit 160 is arranged to transfer, when in operation, heat from the electric motor 22 to the body of water.

With the arrangements of the present technology, heat transfer between vehicle components is mitigated by the separate cooling circuits 140, 160, as the motor 22 generally operates at a significantly higher temperature than the battery 105, the motor 22 being designed to withstand a higher temperature while delivering its specified performance. In contrast, the battery 105 is much more sensitive to higher temperatures, which can be detrimental to its capacity and lifespan. The battery 105 may further not deliver its specified performance unless maintained at a significantly lower temperature (relative to the motor 22). The use of separate cooling circuits thus aids in ensuring that any heat generated by the motor 22 will not raise the temperature of the battery 105, otherwise possible through thermal communication in a shared cooling circuit. The motor 22 is thus also cooled more efficiently using the open cooling circuit 160, as the body of water can supply a much greater thermal mass for absorbing heat from the motor 22 than the limited amount of fluid in the closed cooling circuit.

In some cases, the electrical components (at least the battery 105 and the motor 22) and the cooling circuits can be differently arranged. Another embodiment of a watercraft 210 according to the present technology is schematically illustrated in FIG. 12. Elements of the watercraft 210 that are similar to those of the watercraft 10 retain the same reference numeral and will generally not be described again.

The watercraft 210 includes a closed cooling circuit 240 and an open cooling circuit 260. Similarly to the watercraft 10, the motor 22 and the electronic components (the battery 105, the charger 110, and the inverter 112) are thermally managed by separate cooling circuits. The cooling circuit 240 is arranged to transfer, when in operation, heat from the motor 22 to the body of water via the heat exchanger 73. Using the pump 145, heat exchange fluid is circulated through the motor 22 and the heat exchanger 73. Using the pump 165, water from the body of water is caused to be circulated in the open cooling circuit 260. The cooling circuit 260 is arranged to transfer, when in operation, heat from the battery 105, the charger 110, and the inverter 112 to the body of water.

Yet another embodiment of a watercraft 310 according to the present technology is schematically illustrated in FIG. 13. Elements of the watercraft 310 that are similar to those of the watercraft 10 retain the same reference numeral and will generally not be described again.

The watercraft 310 includes a closed cooling circuit 340 and an open cooling circuit 360. Similarly to the PWC 10, the motor 22 and the battery 105 are thermally managed by separate cooling circuits. The cooling circuit 340 is arranged to transfer, when in operation, heat from the battery 105 to the body of water via the heat exchanger 73. Using the pump 145, heat exchange fluid is circulated through the battery 105 and the heat exchanger 73. Using the pump 165, water from the body of water is caused to be circulated in the open cooling circuit 360. The cooling circuit 360 is arranged to transfer, when in operation, heat from the motor 22, the charger 110, and the inverter 112 to the body of water.

Modifications and improvements to the above-described embodiments of the present technology may become apparent to those skilled in the art. The foregoing description is intended to be exemplary rather than limiting. The scope of the present technology is therefore intended to be limited solely by the scope of the appended claims.

Claims

1. A watercraft for operating on a body of water, the watercraft comprising: a hull;a deck supported by the hull;a propulsion system supported by the hull and configured to propel the watercraft;an electric motor operatively connected to the propulsion system to drive the propulsion system;a battery electrically connected to the electric motor for powering the electric motor; andat least one heat exchanger supported by the hull, the at least one heat exchanger at least partially extending out of the hull such that at least a portion of the at least one heat exchanger is in contact with the body of water,a first cooling circuit being in thermal communication with the at least one heat exchanger and at least one of the battery and the electric motor, the first cooling circuit being configured to circulate a heat exchange fluid therein,a second cooling circuit being in thermal communication with an other one of the at least one of the electric motor and the battery, the second cooling circuit being in fluid communication with the body of water during operation of the watercraft for circulating water from the body of water in the second cooling circuit during use.

2. The watercraft of claim 1, further comprising: a charger electrically connected to the battery; andan inverter electrically connected to the battery.

3. The watercraft of claim 2, wherein the first cooling circuit is further in thermal communication with at least one of the charger and the inverter.

4. The watercraft of claim 3, wherein: the first cooling circuit is arranged to transfer, when in operation, heat from the at least one of the battery and the electric motor and the at least one of the charger and the inverter to the body of water via the at least one heat exchanger; andthe second cooling circuit is arranged to transfer, when in operation, heat from the other one of the battery and the electric motor to the body of water.

5. The watercraft of claim 4, wherein: the at least one of the battery and the electric motor is the battery, the first cooling circuit being in thermal communication with the battery; andthe other one of the battery and the electric motor is the electric motor, the second cooling circuit being in thermal communication with the electric motor.

6. The watercraft of claim 2, wherein the second cooling circuit is further in thermal communication with at least one of the charger and the inverter.

7. The watercraft of claim 6, wherein: the first cooling circuit is arranged to transfer, when in operation, heat from the one of the battery and the electric motor to the body of water via the at least one heat exchanger; andthe second cooling circuit is arranged to transfer, when in operation, heat from the other one of the battery and the electric motor and the at least one of the charger and the inverter to the body of water.

8. The watercraft of claim 1, further comprising a first pump forming a portion of the first cooling circuit, the first pump being arranged to cause the heat exchange fluid to circulate through the first cooling circuit.

9. The watercraft of claim 8, further comprising a second pump forming a portion of the second cooling circuit, the second pump being arranged to cause water from the body of water to circulate through the second cooling circuit.

10. The watercraft of claim 9, wherein the second pump forms a portion of the propulsion system.

11. The watercraft of claim 5, wherein the battery, the charger, and the inverter are isolated from the body of water.

12. The watercraft of claim 1, wherein: the first cooling circuit is a closed cooling loop; andthe second cooling circuit is an open cooling loop.

13. The watercraft of claim 1, further comprising a straddle seat supported by the deck; and wherein the watercraft is a personal watercraft.