Improvements in or relating to a marine propulsion system

Abstract

A marine propulsion system (100) comprising: an engine configured to generate motive power; a propeller shaft (150) operably connected to the engine and configured to receive motive power therefrom; an engine control unit (ECU) configured to control the motive power generated by the engine; and a ventilation system (110) configured to generate an airflow for cooling at least one of the engine and the engine control unit, wherein the ventilation system comprises a power source (130) that is independent of the engine.

Description

[0001] IMPROVEMENTS IN OR RELATING TO A MARINE PROPULSION SYSTEM

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to improvements in or relating to a marine propulsion system and, more specifically, to a ventilation system within a marine propulsions system.

[0004] BACKGROUND TO THE INVENTION

[0005] All marine propulsion systems comprise an engine configured to generate motive power and a propeller configured to receive the motive power and propel a boat through a body of water. The majority of these systems further comprises an engine control unit (ECU) configured to adjust the amount and / or timing of fuel and air provided to the engine to control the amount of motive power generated by the system.

[0006] The engine and ECU are typically enclosed within a cover (or cowl) configured to protect them (and other components) from the external environment. For example, the cover may be designed to prevent the ingress of moisture, especially seawater, to reduce the amount of corrosion and / or rust within the system. However, in use, the engine generates a lot of heat. As such, the temperature within the cover can increase significantly, in use. This temperature increase can reduce the operating efficiency of the engine. For example, if the fuel and / or air provided to the engine is too hot, the efficiency of the engine will be reduced. Moreover, if the ECU becomes too hot it may cease to function altogether, which may result in the failure of the marine propulsion system. Consequently, marine propulsion systems are usually provided with a ventilation system configured to cool components located within the cover, in use.

[0007] Typically, the ventilation system is powered by the engine. As such, the rate of cooling of the ventilation system is directly linked to the speed of the engine. However, the maximum temperature of the engine may be reached after the maximum speed of the engine is reached. Moreover, there is an additional lag before other components surrounding the engine, such as the ECU, reach a maximum temperature, as it takes time for the heat generated by the engine to dissipate throughout the system. Consequently, maximum cooling within the cover may be required when the engine is not operating at its maximum speed (or when the engine is turned off altogether!). Available marine propulsion systems provide no solution to this problem.

[0008] It is against this background that the present invention has arisen. SUMMARY OF THE INVENTION

[0009] According to the present invention there is provided a marine propulsion system comprising: an engine configured to generate motive power; a propeller shaft operably connected to the engine and configured to receive motive power therefrom; an engine control unit configured to control the motive power generated by the engine; and a ventilation system configured to generate an airflow for cooling at least one of the engine and the engine control unit, wherein the ventilation system comprises a power source that is independent of the engine. Preferably, the ventilation system is configured to generate an airflow for cooling the engine and the ECU.

[0010] The marine propulsion system may be an outboard propulsion system. The outboard propulsion system may be configured to attach to a boat. More specifically, the outboard propulsion system may be configured to attach to the stern of a boat.

[0011] The outboard propulsion system may comprise a first portion comprising the engine. The outboard propulsion system may comprise a second portion comprising the propeller shaft. The second portion may be attached to the first portion. The second portion may be configured to rotate with respect to the first portion about a steering axis. Consequently, the second portion may be rotatably attached to the first portion.

[0012] The propeller shaft may comprise a propeller configured to propel a boat through a water body. Motive power may be any source of energy used to produce motion. For example, the motive power may be in the form of mechanical energy, such as rotational energy. Therefore, the motive power generated by the engine may be configured to rotate the propeller shaft. The propeller shaft may be connected to the engine via one or more drive shaft. More specifically, the propeller shaft may be connected to a crankshaft within the engine via one or more drive shaft.

[0013] The engine control unit (ECU) may control the motive power generated by the engine by adjusting the amount of fuel and / or air provided to the engine. Alternatively, or in addition, the ECU may control the motive power generated by the engine by controlling when fuel and / or air is provided to the engine. The ECU may control other components within the marine propulsion system.

[0014] A ventilation system comprising a power source that is independent of the engine allows the ventilation system to operate independently of the engine. The maximum temperature of an engine may be reached after the maximum speed of the engine is reached. Consequently, maximum cooling may be required within the marine propulsion system when the engine is operating (well) below its maximum speed and may even be turned off altogether. Consequently, a ventilation system comprising a power source that is independent of the engine enables the amount of cooling provided to be adjusted based on factors other than engine speed, thus improving the efficiency of the system. Conversely, in traditional marine propulsion systems, the ventilation system receives power from the engine, thus the rate of cooling of the ventilation system is linked to the speed of the engine (only).

[0015] In some embodiments, the marine propulsion system further comprises a temperature sensor. The temperature sensor may be configured to measure a temperature within the marine propulsion system. In use, the ventilation system may be configured to adjust the airflow based on the measured temperature. The temperature sensor may be configured to measure the temperate of the air within the marine propulsion system. Alternatively, or in addition, the temperature sensor may be configured to measure the temperate of a component, such as the engine and / or ECU, within the marine propulsion system.

[0016] The ventilation system may comprise a control unit configured to adjust the airflow based on the measured temperature. The control unit may be in electronic communication with the temperature sensor. The ventilation system control unit may be the ECU.

[0017] Adjusting the airflow generated by the ventilation system, in use, based on the measured temperature may be used to optimise the efficiency of the ventilation system. For example, the amount of cooling provided by the ventilation system may be linked directly to the amount of cooling required, rather than to external and / or secondary factors such as engine speed.

[0018] The temperature sensor may be located on or adjacent to the engine. Alternatively, the temperature sensor may be located on or adjacent to the ECU. Consequently, the temperature sensor may be configured to determine the temperature of the engine or ECU.

[0019] In some embodiments, there may be a plurality of temperature sensors. At least one temperature sensor may be configured to determine the temperature of the engine. At least one temperature sensor may be configured to determine the temperature of the ECU. In such embodiments, the ventilation system may be configured to adjust the airflow based on one or more measured temperature.

[0020] In some embodiments, the ventilation system comprises a fan configured to generate the airflow. The fan may be an electric fan. The fan may be waterproof. The entire ventilation system, including the power source, may be waterproof.

[0021] The ventilation system power source may be remote from the marine propulsion system. For example, the power source may be remotely fitted onboard a boat to which the marine propulsion system is configured to attach. Alternatively, in some embodiments, the power source may for part of the marine propulsions system but be located remotely from the engine. In some embodiments, the power source for the ventilation system is a battery. The battery may be the sole power source.

[0022] In some embodiments, the marine propulsion system further comprises a raw water pump configured to receive motive power from a pulley mounted on a crankshaft of the engine. More specifically, the raw water pump may be directly connected to the pulley mounted on the crankshaft. This is only possible in the present invention because the ventilation system comprises a power source that is independent of the engine instead of driving the ventilation system from the pulley. The pulley may be a damper pulley or a crankshaft pulley.

[0023] The raw water pump may be configured to pump raw water from outside the marine propulsion system to at least one component within the marine propulsion system. The component for receiving the raw water may be a cooling unit. In use, the cooling unit may use the raw water to cool oil and / or fuel within the marine propulsion system.

[0024] For example, the marine propulsion system may comprise a cooling unit for cooling gearbox oil and fuel. The raw water pump may pump raw water to the cooling unit. The cooling unit may comprise a cooling conduit having an inlet for receiving raw water and an outlet for discharging the raw water. The cooling unit may further comprise an oil conduit for conveying oil for use within a gearbox, wherein the oil conduit is located, at least partially, within the cooling conduit. Alternatively, or in addition, the cooling unit may further comprise a fuel conduit for conveying fuel for use within the engine, wherein the fuel conduit is located, at least partially, within the cooling conduit. The oil conduit located within the cooling conduit may be positioned between the inlet and the fuel conduit located within the cooling conduit. The fuel conduit may convey fuel into a fuel tank. The fuel within the fuel tank may be for use within the engine. The fuel may be diesel. The fuel within the fuel conduit may be unused fuel from the engine.

[0025] In use, the cooling unit inlet may be in fluid communication with a body of water. The fluid communication may be provided by an inlet conduit. The inlet conduit may be coupled to the inlet of the cooling unit. Consequently, in use, raw water may be pumped into the cooling unit from a body of water upon which a boat is floating. This may be achieved using the raw water pump.

[0026] In use, the cooling unit outlet may be in fluid communication with the body of water. The fluid communication may be provided by an outlet conduit. The outlet conduit may be coupled to the outlet of the cooling unit. Consequently, in use, raw water may be pumped from the cooling unit to the body of water upon which a boat is floating. This may be achieved using the raw water pump. The oil conduit may be configured to convey oil from the gearbox directly to the cooling conduit, through the cooling conduit, and from the cooling conduit directly back to the gearbox. Consequently, in use, oil may be conveyed through the cooling unit only once before being returned to the gearbox. In other words, the oil conduit may be configured to convey oil that has passed through the cooling unit directly to the gearbox.

[0027] The fuel conduit may be configured to convey fuel from the engine directly to the cooling conduit, through the cooling conduit, and from the cooling conduit directly to the fuel tank. Consequently, in use, fuel may be conveyed through the cooling unit only once before being conveyed to the fuel tank. In other words, the fuel conduit may be configured to convey fuel that has passed through the cooling unit directly to the fuel tank. As a result, the cooling unit may be termed as a 'single-pass', 'once-pass' or '1-pass' cooler.

[0028] In some embodiments, the marine propulsion system further comprises a plurality of panels for covering the engine. The panels may also cover the ECU. The plurality of panels may form a cover. When assembled, the plurality of panels may define a compartment within the cover. The compartment may be configured to receive the engine. Consequently, in some embodiments, the marine propulsion system further comprises a cover forming a compartment for receiving the engine. As such, there is also provided a cover for receiving the previously disclosed engine, ECU, and ventilation system. In particular, the cover may form a compartment for receiving the engine, and may comprise an opening configured to allow an airflow to enter the compartment and a vent configured to allow airflow to exit the compartment.

[0029] The cover may be configured to protect components of the marine propulsion system, such as the engine and / or the ECU, from the external environment. However, the cover may also trap heat generate by the engine within the marine propulsion system. Therefore, the cover may comprise a vent configured to allow the airflow to exit the compartment. The vent may provide an aperture through which the airflow generated by the ventilation system may pass, thus enabling heat generated within the cover, and carried by the airflow, to dissipate more efficiently. Preferably, the cover comprises a plurality of vents as previously described.

[0030] In use, the engine may be covered, at least partially, by the cover. In other words, the engine may be located in the compartment of the cover. The vent may be located in the third of the cover furthest from the propeller shaft. The third of the cover furthest from the propeller shaft may be the top third, or at least the top half. This enables the vent to more efficiently expel heat from within the cover, as heat is known to rise. In some embodiments, the ventilation system is configured to generate the airflow in the direction of the vent. Generating the airflow in the direction of the vent increases the rate at which air is expelled from the compartment. For example, the fan may be located adjacent to the vent. As such, the fan may expel air out through the vent. This may generate a negative pressure within the compartment of the cover. This effect improves the efficiency of the ventilation system.

[0031] In some embodiments, the cover comprises an opening configured to allow air to enter the compartment. More specifically, the opening may allow fresh (cool) air to enter the compartment. The cover may comprise a plurality of openings. Expelling air from within the compartment generates a negative pressure within the compartment that draws fresh air into the compartment via the opening. This process of expelling air out from the cover and drawing fresh air into the cover may generate the airflow for cooling at least one of the engine and the engine control unit. Preferably, the ventilation system is positioned between the vent and the opening. However, in some embodiments, the vent may also be opening.

[0032] In some embodiments, the marine propulsion system comprises an engine airflow channel configured, in use, to convey the airflow from the opening to the vent via the engine. The engine airflow channel may ensure that air that enters the compartment passes by the engine before being expelled from the compartment. This increases the amount of heat energy transferred from the engine to the airflow, thus increasing the efficiency of the ventilation system. The engine airflow channel may be a continuous void between the opening and the vent. The continuous void may be created by the space between components within the marine propulsion system. In some embodiments, the continuous void may be created, at least in part, by an internal duct (or passageway). The internal duct, or at least a part thereof, may be attached to at least on panel.

[0033] In some embodiments, the marine propulsion system comprises an ECU airflow channel configured, in use, to convey the airflow from the opening to the vent via the ECU. The ECU airflow channel may be an ECU airflow passageway. The ECU airflow channel may ensure that air that enters the compartment passes by the ECU before being expelled from the compartment. This increases the amount of heat energy transferred from the ECU to the airflow, thus increasing the efficiency of the ventilation system. The ECU airflow channel may be a continuous void between the opening and the vent. The continuous void may be created by the space between components within the marine propulsion system. In some embodiments, the continuous void may be created, at least in part, by an internal duct (or passageway). The cover may be configured to receive the aforementioned engine, engine control unit and ventilation system. The cover may comprise: a compartment for receiving an engine; an opening configured to allow an airflow to enter the compartment; and a vent configured to allow airflow to exit the compartment, wherein at least one of the vent and the opening comprises a membrane configured to minimise water ingress into the compartment. Minimising water ingress increases the longevity of the engine, engine control unit and ventilation system, in addition to other components within the marine propulsion system.

[0034] In some embodiments, the membrane is configured to allow the passage of air and prevent the passage of water. Consequently, the membrane may be a semipermeable membrane. The semipermeable membrane further reduces the amount of water ingress into the compartment. In some embodiments, each of the vent and the opening comprises a membrane configured to allow the passage of air and prevent the passage of water.

[0035] In some embodiments, the membrane is hydrophobic. For example, the membrane may comprise a hydrophobic treatment or coating. Alternatively, or in addition, the membrane may be manufactured from a hydrophobic material. In some embodiments, each of the vent and the opening comprises a hydrophobic membrane. In some embodiments, the membrane is a woven polyethylene terephthalate (PET) membrane.

[0036] The invention will now be further and more particularly described, by way of example only, with reference to the accompanying drawing.

[0037] FIGURES

[0038] Figure 1 shows a marine propulsion system comprising a ventilation system according to the present invention;

[0039] Figure 2 shows a section of the ECU airflow channel according to some embodiments of the present invention; and

[0040] Figure 3 shows a raw water pump according to some embodiments of the present invention.

[0041] DETAILED DESCRIPTION

[0042] Figure 1 shows a marine propulsion system 100 comprising a ventilation system 110. More specifically, the marine propulsion system 100 comprises a cover 120 that encloses an engine configured to generate motive power; an engine control unit (ECU) configured to control the motive power generated by the engine; and the ventilation system 110. The marine propulsion system 100 further comprises a propeller shaft 150 operably connected to the engine and configured to receive motive power therefrom.

[0043] The ventilation system 110 comprises a power source 130 that is independent of the engine. As such, the power source, hence the ventilation system, does not receive motive power from the engine. Instead, the power source independently provides power to the ventilation system. In some embodiments, as shown in figure 1, the power source 130 is located remotely from the marine propulsion system 100. For example, the power source 130 may be located onboard a vessel or boat to which the marine propulsion system 100 is configured to attach. The power source 130 for the ventilation system 110 may be a battery. In use, the ventilation system 110 is configured to generate an airflow for cooling at least one of the engine and the engine control unit. In particular, the ventilation system 110 comprises a fan 112 configured to generate the airflow. In some embodiments, the fan is an electric fan powered by a battery.

[0044] The marine propulsion system further comprises a temperature sensor (not shown in the accompanying drawing) configured to measure a temperature within the marine propulsion system. There may be a plurality of temperature sensors. Each temperature sensor may be located within the cover 120. The ventilation system 110 may be configured to adjust the airflow generated, in use, based on the measured temperature.

[0045] The cover 120 may comprise at least one side panel 125 and at least one top panel 127. The side panel 125 may be releasably attached to the top panel 127. The cover 120 comprises a vent 122 configured to allow the airflow to exit a compartment within the cover 120 that is configured to receive the engine, ECU, and ventilation system 110. The vent 122 provides an aperture through which the airflow generated by the ventilation system 110 may pass. In some embodiments, the vent 122 is partially covered with a cover plate (not shown in the accompanying drawing). The cover plate may reduce the amount of water ingress into the compartment, in use. The cover plate may be substantially parallel to and spaced apart from a portion of a surface of the cover comprising the vent. As such, the aperture created by the vent and the cover plate may be substantially perpendicular to the portion of the surface of the cover comprising the vent.

[0046] The vent 122 is located in the third of the cover 120 furthest from the propeller shaft 150. The vent 112 is also located above the engine, in use. These factors enable the vent 112 to more efficiently expel heat from within the compartment of the cover 120, as heat is known to rise.

[0047] The ventilation system 110 is configured to generate an airflow in the direction of the vent 122, in use. As such, in some embodiments, as shown in figure 1, a fan 112 of the ventilation system 110 is located adjacent to the vent 122. For example, the fan 112 may be located less than 200 mm from the vent 122 and, more preferably, less than 100 mm or less than 50 mm from the vent 122.

[0048] The cover 120 further comprises at least one opening 124 configured to allow air to enter the compartment of the 120. In particular, the opening 124 is configured to allow air to enter the compartment of the cover 120 configured to receive the engine, ECU and ventilation system 110. In fact, the cover 120 comprises a plurality of openings 124. The ventilation system is positioned between the vent 122 and the opening(s) 124.

[0049] The vent 122 and opening(s) 124 are located at opposing ends of an engine airflow channel. In use, the engine airflow channel is configured to ensure air travelling between an opening 124 and the vent 122 is conveyed directly past the engine. Similarly, the vent 122 and opening(s) 124 are located at opposing ends of an ECU airflow channel. In use, the ECU airflow channel is configured to ensure air travelling between an opening 124 and the vent 122 is conveyed directly past the engine. The engine airflow channel and the ECU airflow channel may, at least partially, overlap, particularly in the vicinity of the opening(s) 124 and / or vent 122.

[0050] Figure 2 shows a section of the ECU airflow channel according to some embodiments of the present invention. The ECU airflow channel may comprise an internal duct 210. The internal duct 210 may be configured to convey airflow between the opening 124 and the ECU. The opening 124 may convey air directly into the internal duct 210. The internal duct 210 may comprise a plurality of parts 211, 212. The internal duct 210 may comprise an outlet 215 for discharging airflow towards the ECU. The internal duct 210 may comprise an exit 218 for discharging airflow towards a control module. The control module may form part of the marine propulsion system 100.

[0051] The internal duct 210 may comprise a plurality of parts 211,212. At least one part of the internal duct 211 may be attached to a side panel 125 of the cover 120. At least one part of the internal duct 212 may be attached to a top panel 127 of the cover 120. The part of the internal duct 211 connected to the side panel 125 may connect to the part of the internal duct 212 attached to the top panel 127 via a deformable joining piece 225. This may limit the amount of airflow escaping the internal duct 210 at the joint between the two parts of the duct 211, 212. The deformable joining piece 225 may be a foam joining piece. The deformable joining piece 225 may be attached to one part of the internal duct 211, 212. The internal duct 210 may also form a part of the engine airflow channel.

[0052] Figure 3 shows a raw water pump 300 according to some embodiments of the present invention. In some embodiments, the marine propulsion system 100 of figure 1 also comprises a raw water pump 300 operably connected to the engine. As such, the raw water pump 300 may be located within the cover 120. In particular, the raw water pump is configured to receive motive power from a pulley 310 mounted on a crankshaft of the engine. The pulley 310 may be mounted on a crankshaft bolt 320 of the crankshaft. The raw water pump 300 may comprise an adaptor 330 configured to transfer power received from the pulley 310 to the raw water pump 300.

[0053] The raw water pump 300 may be held in place using a mount 340. The mount 340 may be a mounting bracket. The mount 340 may be secured to the marine propulsion system 100 via one or more bolt 350. In some embodiments, the mount 340 is secured to the engine via the one or more bolt 350. The raw water pump 300 may comprise a flange 360. The flange 360 may attached to the adaptor 330. The mount 340 may be connected to the flange 360.

[0054] The raw water pump 300 may be configured to pump raw water from outside the marine propulsion system 100 to at least one component within the marine propulsion system 100. The component for receiving the raw water may be a cooling unit. The cooling unit may be located within the cover 120. In use, the cooling unit may use the raw water to cool oil and / or fuel within the marine propulsion system 100.

[0055] Various further aspects and embodiments of the present invention will be apparent to those skilled in the art in view of the present disclosure, "and / or" where used herein is to be taken as specific disclosure of each of the two specified features or components with or without the other. For example, "A and / or B" is to be taken as specific disclosure of each of (i) A, (ii) B and (iii) A and B, just as if each is set out individually herein.

[0056] Unless context dictates otherwise, the descriptions and definitions of the features set out above are not limited to any particular aspect or embodiment of the invention and apply equally to all aspects and embodiments that are described. It will further be appreciated by those skilled in the art that although the invention has been described by way of example with reference to several embodiments, it is not limited to the disclosed embodiments and that alternative embodiments could be constructed without departing from the scope of the invention as defined in the appended claims.

Claims

CLAIMS1. A marine propulsion system comprising: an engine configured to generate motive power; a propeller shaft operably connected to the engine and configured to receive motive power therefrom; an engine control unit configured to control the motive power generated by the engine; and a ventilation system configured to generate an airflow for cooling at least one of the engine and the engine control unit, wherein the ventilation system comprises a power source that is independent of the engine.

2. The marine propulsion system according to claim 1, further comprising a temperature sensor configured to measure a temperature within the marine propulsion system, and wherein, in use, the ventilation system is configured to adjust the airflow based on the measured temperature.

3. The marine propulsion system according to any preceding claim, wherein the ventilation system comprises a fan configured to generate the airflow.

4. The marine propulsion system according to any preceding claim, wherein the power source for the ventilation system is a battery.

5. The marine propulsion system according to any preceding claim, further comprising a raw water pump configured to receive motive power from a pulley mounted on a crankshaft of the engine.

6. The marine propulsion system according to any preceding claim, further comprising a cover forming a compartment for receiving the engine, wherein the cover comprises a vent configured to allow the airflow to exit the compartment.

7. The marine propulsion system according to claim 6, wherein the engine is covered, at least partially, by the cover, and wherein the vent is located in the third of the cover furthest from the propeller shaft.

8. The marine propulsion system according to claim 6 or 7, wherein the ventilation system is configured to generate the airflow in the direction of the vent.

9. The marine propulsion system according to any of claims 6 to 8, wherein the cover comprises an opening configured to allow air to enter the compartment.

10. The marine propulsion system according to claim 9, further comprising an engine airflow channel configured, in use, to convey the airflow from the opening to the vent via the engine.

11. The marine propulsion system according to claim 9 or 10, further comprising an ECU airflow channel configured, in use, to convey the airflow from the opening to the vent via the ECU.

12. The marine propulsion system according to any of claims 9 to 11, wherein at least one of the vent and the opening comprises a membrane configured to minimise water ingress into the compartment.

13. The marine propulsion system according to claim 12, wherein the membrane is configured to allow the passage of air and prevent the passage of water.

14. The marine propulsion system according to claim 12 or 13, wherein the membrane is hydrophobic.

15. The marine propulsion system according to any of claims 12 to 14 wherein the membrane is a woven polyethylene terephthalate (PET) membrane.

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