Patent Description:
An outboard motor including pumps that pump water from the outside of an outboard motor body is known in general. Such an outboard motor is disclosed in <CIT>, for example.

<CIT> discloses a cooler for an outboard motor including a main pump that supplies cooling water to an engine unit. The main pump is disposed in an upper portion of the outboard motor and is a non-positive displacement electric pump. In addition, the cooler includes an engine-driven secondary pump disposed in a lower portion of the outboard motor and driven by the driving force of an engine of the engine unit. The secondary pump is a positive-displacement pump, and pumps water from the outside of the outboard motor via a water inlet. The secondary pump supplies the pumped water to the main pump. That is, the secondary pump is a pump that primes the main pump. The main pump is driven to flow the cooling water into a cooling water passage of the engine unit.

However, in a conventional outboard motor as disclosed in <CIT>, there is no water cooling means that operates while the engine is stopped, and thus when the engine is stopped, electrical components and fuel in a fuel tank cannot be cooled by cooling water. Therefore, when the electrical components operate while the engine is stopped, the electrical components conceivably generate heat. Even when the electrical components do not operate, it is conceivably necessary to use high heat resistant materials for the electrical components. Immediately after the engine is stopped (at the time of dead soak), the temperature of engine oil is relatively high, and thus the temperature inside the engine in which the engine oil is placed is conceivably relatively high. In addition, the temperature of the fuel in the fuel tank provided in the vicinity of the engine is conceivably relatively high due to the relatively high temperature of the engine. Thus, the size of a fuel vaporized gas treatment system is conceivably increased in order to cope with an increase in the temperature of the fuel. In such a case, the layout in the outboard motor is conceivably further restricted.

It is an object of the present invention to provide an outboard motor that cools a cooling target including at least one of fuel in a fuel tank and an electrical component with cooling water even when an engine is stopped. According to the present invention, said object is solved by an outboard motor having the features of independent claim <NUM>. Preferred embodiments are laid down in the dependent claims.

An outboard motor according to the present invention includes a first cooling water passage through which first cooling water including water outside an outboard motor body passes to cool a first cooling target including at least one of fuel in a fuel tank and an electrical component other than an engine, and a first pump that is an electric pump configured to pump the first cooling water from an outside of the outboard motor body and flow the first cooling water into the first cooling water passage.

In an outboard motor according to a preferred embodiment, the first pump is an electric pump configured to pump the first cooling water from the outside of the outboard motor body and flow the first cooling water into the first cooling water passage. Accordingly, even while the engine is stopped, the first pump as an electric pump configured to pump the first cooling water from the outside is driven by electric power. Therefore, even while the engine is stopped, the first pump is driven such that the first cooling target including at least one of the electrical component and the fuel in the fuel tank is cooled with the first cooling water.

In an outboard motor according to a preferred embodiment, the engine is preferably configured to rotate a drive shaft connected to a propeller, the outboard motor preferably further includes a rotary electric machine configured to drive the outboard motor by rotating the drive shaft, the first cooling target preferably includes the electrical component, and the electrical component preferably includes a component of a power supply system configured to supply electric power to the rotary electric machine. It is conceivable that the outboard motor is driven by both the engine and the rotary electric machine (the hybrid technology of the engine and the rotary electric machine is used). In such a case, the component of the power supply system configured to supply electric power to the rotary electric machine conceivably generates heat when the rotary electric machine is driven while the engine is stopped. In this regard, according to a preferred embodiment, the first cooling target includes the electrical component, and the electrical component includes the component of the power supply system configured to supply electric power to the rotary electric machine such that the first pump is driven even while the engine is stopped. Thus, the component of the power supply system as the first cooling target is cooled with the first cooling water. Consequently, even when the hybrid technology of the engine and the rotary electric machine configured to drive the outboard motor is applied to the outboard motor, the electrical component, for example, is effectively cooled.

An outboard motor according to the present invention further includes a second cooling water passage through which second cooling water passes to cool a second cooling target that is different from the first cooling target and includes the engine, and a second pump configured to flow the second cooling water into the second cooling water passage. Accordingly, the outboard motor includes the first pump and the second pump, and thus unlike a case in which all the cooling targets are cooled by one pump, the cooling target (first cooling target) cooled by the first pump and the cooling target (second cooling target) cooled by the second pump are dispersed. Therefore, an increase in the size of each of the first pump and the second pump is significantly reduced or prevented. Consequently, the first pump and the second pump, in which increases in their sizes are significantly reduced or prevented, are dispersed and easily disposed in a limited space inside the outboard motor.

In such a case, the first pump is preferably configured to have a cooling water pumping capacity per unit time smaller than a cooling water pumping capacity per unit time of the second pump. Accordingly, an increase in the size of the first pump is further significantly reduced or prevented.

In an outboard motor including the second pump, both the first pump and the second pump are preferably positive-displacement pumps. When one of the first pump and the second pump is a non-positive displacement pump, it is necessary to prime the non-positive displacement pump from the outside of the outboard motor body. In this regard, according to a preferred embodiment, both the first pump and the second pump are positive-displacement pumps, and thus both the first pump and the second pump easily pump water outside the outboard motor body without priming the first pump and the second pump.

In an outboard motor including the second pump, the first cooling water passage and the second cooling water passage preferably include a common water inlet through which the first cooling water and the second cooling water are taken in upstream of the first cooling target and upstream of the second cooling target. Accordingly, the water inlet through which the first cooling water is taken in and the water inlet through which the second cooling water is taken in are shared, and thus the complex structure of the outboard motor is significantly reduced or prevented.

In an outboard motor including the second pump, the second pump is preferably an engine-driven pump configured to be driven by the drive shaft when the engine drives the drive shaft. The amount of heat generated by the engine included in the second cooling target increases as the rotation speed increases. Therefore, the second pump is an engine-driven pump, as described above, such that the flow rate of the second cooling water that flows through the second cooling water passage is increased according to an increase in the amount of heat generated by the engine.

In an outboard motor including the second pump, the engine is preferably configured to rotate a drive shaft connected to a propeller, and the first cooling target preferably includes a rotary electric machine configured to drive the outboard motor by rotating the drive shaft. Accordingly, even while an engine is stopped, the rotary electric machine that generates heat when driven is cooled with the first cooling water (first pump).

An outboard motor including the rotary electric machine preferably further includes a rotation speed detector configured to detect a rotation speed of the rotary electric machine, and driving of the first pump is preferably controlled based on the rotation speed of the rotary electric machine detected by the rotation speed detector. Accordingly, the rotation speed of the rotary electric machine is detected such that the first pump is driven as necessary. For example, when the rotary electric machine is being driven and the electrical component is generating heat, the first pump is effectively driven such that the electrical component is effectively cooled. Furthermore, when the rotary electric machine is included in the first cooling target, the rotary electric machine is effectively cooled.

In an outboard motor according to a preferred embodiment, the first pump is preferably configured to be drivable while the engine is stopped. Accordingly, the first pump is driven while the engine is stopped, and thus the first cooling target is cooled even while the engine is stopped.

In an outboard motor according to a preferred embodiment, the first cooling target preferably includes the electrical component, the electrical component preferably includes a component of a power supply system including an inverter and a converter, and the first cooling water passage preferably includes a portion configured to cool the inverter upstream of a portion configured to cool the converter. Accordingly, the inverter that generates more heat than the converter is cooled in a relatively upstream portion of the first cooling water passage. Consequently, the first cooling water on the upstream side on which the temperature is lower than that on the downstream side effectively cools the inverter that generates a large amount of heat.

An outboard motor according to a preferred embodiment preferably further includes a temperature detector configured to detect a temperature of the first cooling target, and driving of the first pump is preferably controlled based on the temperature detected by the temperature detector. When the temperature of the first cooling target becomes abnormal in spite of driving the first pump, the first pump may not be operating normally (abnormalities may have occurred). In consideration of this, driving of the first pump is controlled based on the temperature detected by the temperature detector. Accordingly, for example, when the temperature of the first cooling target is abnormal, driving of the first pump is limited. Consequently, driving of the first pump in an abnormal state is significantly reduced or prevented.

An outboard motor according to a preferred embodiment preferably further includes a water pressure detector configured to detect a water pressure of the first cooling water that flows through the first cooling water passage, and driving of the first pump is preferably stopped when the water pressure detected by the water pressure detector is equal to or lower than a water pressure threshold. When the water pressure of the first cooling water becomes equal to or lower than the water pressure threshold in spite of driving the first pump, the first pump may not be operating normally (abnormalities may have occurred). In consideration of this, driving of the first pump is stopped when the water pressure detected by the water pressure detector is equal to or lower than the water pressure threshold. Accordingly, when there is a possibility that the first pump is not operating normally, driving of the first pump is stopped. Consequently, driving of the first pump in an abnormal state is significantly reduced or prevented.

In an outboard motor according to a preferred embodiment, the first cooling target preferably includes the fuel in the fuel tank, and the first cooling water passage is preferably disposed along the fuel tank such that the first cooling water in the first cooling water passage cools the fuel in the fuel tank. Accordingly, the temperature becomes high immediately after an engine is stopped, and thus the fuel in the fuel tank, which is preferably cooled even while the engine is stopped, is cooled with the first cooling water. Consequently, even while the engine is stopped, the fuel in the fuel tank is cooled such that volatilization of the fuel is significantly reduced or prevented.

In an outboard motor according to a preferred embodiment, the first cooling target preferably includes a rectifier/regulator as the electrical component, and the first cooling water passage is preferably disposed along the rectifier/regulator such that the first cooling water in the first cooling water passage cools the rectifier/regulator. Accordingly, the rectifier/regulator is cooled even while the engine is stopped. Consequently, even when the temperature of the rectifier/regulator is relatively high after the engine is stopped, the rectifier/regulator is effectively cooled with the first cooling water.

The above and other elements, features, steps, characteristics and advantages of preferred embodiments will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.

Preferred embodiments are hereinafter described with reference to the drawings.

The structure of a marine vessel <NUM> according to a first preferred embodiment is now described with reference to <FIG>. As shown in <FIG>, the marine vessel <NUM> includes an outboard motor <NUM>, a hull <NUM>, and a remote control <NUM>.

As shown in <FIG>, the outboard motor <NUM> is attached to a rear portion of the hull <NUM>. The outboard motor <NUM> includes an outboard motor body 101a. The outboard motor body 101a is a case that houses each portion of the outboard motor <NUM>. Specifically, the outboard motor body 101a includes a cowl <NUM> that houses an engine <NUM>, an upper case <NUM> provided below the engine <NUM>, a lower case <NUM> provided below the upper case <NUM>, and a bracket <NUM> disposed in front of the upper case <NUM>. The outboard motor <NUM> is attached to the hull <NUM> by the bracket <NUM> so as to be rotatable about an upward-downward axis and a horizontal axis. The engine <NUM> is an example of a "second cooling target".

As shown in <FIG> and <FIG>, the outboard motor <NUM> includes the engine <NUM>, a propulsion motor <NUM>, a drive shaft <NUM>, a gearing <NUM>, a propeller shaft <NUM>, a propeller <NUM>, a first pump <NUM>, and a second pump <NUM>. That is, the outboard motor <NUM> is a hybrid outboard motor driven by the engine <NUM> and driven by the propulsion motor <NUM>. The propulsion motor <NUM> is an example of a "rotary electric machine configured to drive the outboard motor".

The engine <NUM> is an internal combustion engine driven by combustion of gasoline, light oil, or the like. The propulsion motor <NUM> is an electric motor driven by electric power supplied from an inverter <NUM> described below. The propulsion motor <NUM> is disposed adjacent to or in the vicinity of the drive shaft <NUM> in the upper case <NUM>, for example. The propulsion motor <NUM> may be provided in a portion other than the upper case <NUM> in the outboard motor <NUM>. For example, the propulsion motor <NUM> may be provided in the lower case <NUM>.

The drive shaft <NUM> is coupled to a crankshaft (not shown) of the engine <NUM>. The drive shaft <NUM> is coupled to a shaft (not shown) of the propulsion motor <NUM>. Thus, the drive shaft <NUM> acquires each of a driving force from the engine <NUM> and a driving force from the propulsion motor <NUM>. The drive shaft <NUM> extends in an upward-downward direction. An upper portion of the drive shaft <NUM> passes through the upper case <NUM>, and a lower portion of the drive shaft <NUM> is disposed in the lower case <NUM>.

The gearing <NUM> reduces rotation of the drive shaft <NUM> and transmits the rotation to the propeller shaft <NUM>. That is, the gearing <NUM> transmits, to the propeller shaft <NUM> that rotates about a rotation axis extending in a forward-rearward direction, the driving force of the drive shaft <NUM> that rotates about a rotation axis extending in the upward-downward direction. Specifically, the gearing <NUM> switches the rotation direction (a forward movement direction and a reverse movement direction) of the propeller shaft <NUM>. The gearing <NUM> is disposed in the lower case <NUM>.

The propeller <NUM> (screw) is connected to the propeller shaft <NUM>. The propeller <NUM> is driven to rotate about a rotation axis that extends in the forward-rearward direction. The propeller <NUM> generates a thrust in an axial direction by rotating in water. The propeller <NUM> moves the hull <NUM> forward or rearward according to the rotation direction.

As shown in <FIG>, the first pump <NUM> pumps first cooling water L1 used to cool a converter <NUM> and the inverter <NUM> described below from the outside of the outboard motor body 101a. The first pump <NUM> flows the first cooling water L1 into a first cooling water passage <NUM>. Specifically, the first pump <NUM> takes in the first cooling water L1 via a water inlet 9a. The water inlet 9a is provided in the lower case <NUM>, for example. After flowing through the first cooling water passage <NUM>, the first cooling water L1 is discharged to the outside via a water outlet 9b of the outboard motor body 101a.

Specifically, as shown in <FIG>, the first pump <NUM> is an electric pump, and is driven when electric power is supplied thereto. In other words, according to the first preferred embodiment, the first pump <NUM> is driven when electric power is supplied thereto even while the engine <NUM> is stopped. The first pump <NUM> includes a pump motor <NUM>, a shaft <NUM>, and an impeller <NUM>.

The pump motor <NUM> rotates the shaft <NUM> using electric power from a pump power supply <NUM> (see <FIG>) described below. Furthermore, the shaft <NUM> is fixed to the impeller <NUM>, and transmits a driving force from the pump motor <NUM> to the impeller <NUM>. Thus, the impeller <NUM> rotates.

As shown in <FIG>, the first pump <NUM> is a positive-displacement pump that pumps the first cooling water L1 by a change in volume. Thus, the first pump <NUM> pumps water from the water inlet 9a provided upstream (downward) of the first pump <NUM> and flows the water into the first cooling water passage <NUM>. Specifically, the first pump <NUM> includes a housing <NUM>, a pump case <NUM>, a suction port <NUM>, a suction passage <NUM>, a discharge port <NUM>, and a discharge passage <NUM>.

The impeller <NUM> includes a plurality of vanes disposed at predetermined rotation angle intervals. The impeller <NUM> is made of rubber, for example, and is elastically deformable. The impeller <NUM> is housed with the deformed vanes in the pump case <NUM>. Ends of the vanes of the impeller <NUM> contact an inner wall of the pump case <NUM>. The impeller <NUM> rotates in an eccentric state. That is, the center 74a of the pump case <NUM> and the center 72a of the shaft <NUM> are shifted from each other in a plan view (as viewed in the axial direction).

The pump case <NUM> is cylindrical. The suction port <NUM> and the discharge port <NUM> are provided on the outer periphery of the pump case <NUM>. Specifically, the suction port <NUM> is disposed on the outer periphery of the pump case <NUM> at a position at which the volume of a space partitioned by the pump case <NUM> and the vanes of the impeller <NUM> is increased. The suction passage <NUM> is connected to the suction port <NUM> and the water inlet 9a. The discharge port <NUM> is disposed on the outer periphery of the pump case <NUM> at a position at which the volume of a space partitioned by the pump case <NUM> and the vanes of the impeller <NUM> is reduced. The discharge passage <NUM> is connected to the discharge port <NUM>. The discharge passage <NUM> is connected to the first cooling water passage <NUM>.

According to the first preferred embodiment, the cooling water pumping capacity per unit time of the first pump <NUM> is smaller than the cooling water pumping capacity per unit time of the second pump <NUM>. For example, the flow rate (discharge rate) of the first pump <NUM> is <NUM> liters/minute or less, and preferably <NUM> liters/minute or more and <NUM> liters/minute or less. Thus, the cooling water pumping capacity per unit time of the first pump <NUM> is set to <NUM> liters/minute or more such that a cooling target is cooled even when the cooling target includes the converter <NUM> and the inverter <NUM> (and additionally a fuel tank <NUM> and a rectifier/regulator (REC/REG) <NUM>, for example, as indicated in the third preferred embodiment described later). In addition, the cooling water pumping capacity per unit time of the first pump <NUM> is set to <NUM> liters/minute or less such that an increase in the size of the first pump <NUM> is further significantly reduced or prevented.

As shown in <FIG>, the second pump <NUM> pumps second cooling water L2 used to cool the engine <NUM> etc. from the outside of the outboard motor body 101a, and flow the second cooling water L2 into a second cooling water passage <NUM>. Specifically, the second pump <NUM> takes in the second cooling water L2 via the water inlet 9a. That is, according to the first preferred embodiment, the first pump <NUM> and the second pump <NUM> pump water from the common water inlet 9a.

Specifically, as shown in <FIG>, the second pump <NUM> is an engine-driven pump. That is, the second pump <NUM> is driven by the drive shaft <NUM> when the drive shaft <NUM> is driven by the engine <NUM>. For example, an impeller <NUM> of the second pump <NUM> rotates integrally with the drive shaft <NUM>. That is, the second pump <NUM> is driven when the engine <NUM> is driven, and is stopped when the engine <NUM> is stopped.

Similarly to the first pump <NUM> as a positive-displacement pump, the second pump <NUM> is a positive-displacement pump that pumps the second cooling water L2 by a change in volume.

As shown in <FIG>, the outboard motor <NUM> includes the first cooling water passage <NUM>, the converter <NUM>, and the inverter <NUM>. The converter <NUM> and the inverter <NUM> are examples of a "first cooling target", an "electrical component", or a "component of a power supply system".

The first cooling water passage <NUM> flows the first cooling water L1 discharged from the first pump <NUM>. The first cooling water passage <NUM> includes a first portion 10a, an inverter water jacket 10b, a second portion 10c, a converter water jacket 10d, and a third portion 10e. The inverter water jacket 10b is an example of a "portion configured to cool the inverter". The converter water jacket 10d is an example of a "portion configured to cool the converter".

The first portion 10a, the inverter water jacket 10b, the second portion 10c, the converter water jacket 10d, and the third portion 10e are sequentially disposed in this order from the water inlet 9a toward the water outlet 9b. That is, the inverter water jacket 10b is disposed upstream of the converter water jacket 10d.

The first portion 10a connects the first pump <NUM> to the inverter <NUM> (inverter water jacket 10b). The inverter water jacket 10b is adjacent to or in the vicinity of the inverter <NUM>, and absorbs heat from the inverter <NUM> by the first cooling water L1. The second portion 10c connects the inverter <NUM> (inverter water jacket 10b) to the converter <NUM> (converter water jacket 10d). The converter water jacket 10d is adjacent to or in the vicinity of the converter <NUM>, and absorbs heat from the converter <NUM> by the first cooling water L1. The third portion 10e connects the converter <NUM> (converter water jacket 10d) to the water outlet 9b.

According to the first preferred embodiment, the converter <NUM> and the inverter <NUM> are components of a power supply system that supply electric power to the propulsion motor <NUM>. The converter <NUM> converts DC power from a battery (not shown) provided in the hull <NUM> or the outboard motor body 101a into DC power having a predetermined voltage. That is, the converter <NUM> is a DC-DC converter. The inverter <NUM> converts the power supplied from the converter <NUM> into AC power, and supplies the converted power to the propulsion motor <NUM>.

As shown in <FIG>, the outboard motor <NUM> includes an engine control unit (ECU) <NUM>, the pump power supply <NUM>, a switch <NUM>, a rotation speed detector 16a, a temperature detector 16b, a water pressure detector 16c, and a thermal switch 16d.

The ECU <NUM> controls driving of the engine <NUM>, driving of the propulsion motor <NUM>, and driving of the first pump <NUM>. For example, the ECU <NUM> controls the rotation speed of the engine <NUM>, the rotation speed of the propulsion motor <NUM>, and switching of the state (shift position) of the gearing <NUM> based on operation signals from the remote control <NUM> provided on the hull <NUM>.

The switch <NUM> includes a relay circuit, for example. The switch <NUM> switches between a state in which a current from the pump power supply <NUM> is supplied to the first pump <NUM> and a state in which the current from the pump power supply <NUM> is not supplied to the first pump <NUM> based on a command from the ECU <NUM>.

The rotation speed detector 16a is a sensor that detects the rotation speed of the propulsion motor <NUM> and transmits information about the detected rotation speed to the ECU <NUM>. The temperature detector 16b is a sensor provided inside, adjacent to, or in the vicinity of the inverter <NUM> and that detects the temperature of the inverter <NUM>. The temperature detector 16b transmits information about the detected temperature of the inverter <NUM> to the ECU <NUM>. The water pressure detector 16c is a sensor that detects a water pressure in the first portion 10a of the first cooling water passage <NUM>. The water pressure detector 16c transmits information about the detected water pressure in the first portion 10a to the ECU <NUM>.

The thermal switch 16d is disposed in a current path between the pump power supply <NUM> and the first pump <NUM>. The thermal switch 16d is disposed inside, adjacent to, or in the vicinity of the first pump <NUM>, and when the temperature of the first pump <NUM> (thermal switch 16d) becomes equal to or higher than a predetermined temperature threshold (when the first pump <NUM> has an abnormal temperature) or when a current that flows through the first pump <NUM> becomes an overcurrent, the current path between the pump power supply <NUM> and the first pump <NUM> is disconnected.

According to the first preferred embodiment, the ECU <NUM> controls driving of the first pump <NUM> by switching the switch <NUM> based on the rotation speed of the propulsion motor <NUM> detected by the rotation speed detector 16a, the temperature of the inverter <NUM> detected by the temperature detector 16b, and the water pressure in the first cooling water passage <NUM> detected by the water pressure detector 16c.

For example, the ECU <NUM> performs a control to drive the first pump <NUM> when the rotation speed of the propulsion motor <NUM> is equal to or higher than a predetermined value (when the propulsion motor <NUM> is driven). The ECU <NUM> performs a control to stop driving the first pump <NUM> when the temperature of the inverter <NUM> detected by the temperature detector 16b is equal to or higher than the temperature threshold of the inverter <NUM>. At this time, the ECU <NUM> performs a control to stop driving the propulsion motor <NUM> in addition to the control to stop driving the first pump <NUM>. Furthermore, the ECU <NUM> performs a control to stop driving the first pump <NUM> when the water pressure detected by the water pressure detector 16c is equal to or lower than a water pressure threshold. At this time, the ECU <NUM> performs a control to stop driving the propulsion motor <NUM> in addition to the control to stop driving the first pump <NUM>.

As shown in <FIG> and <FIG>, the outboard motor <NUM> includes the second cooling water passage <NUM>, an exhaust manifold <NUM>, a thermostat <NUM>, the fuel tank <NUM>, the REC/REG <NUM>, and an oil cooling heat exchanger <NUM> (hereinafter referred to as a "heat exchanger <NUM>"). The exhaust manifold <NUM>, the fuel tank <NUM>, the REC/REG <NUM>, and the heat exchanger <NUM> are examples of a "second cooling target".

The second cooling water passage <NUM> flows the second cooling water L2 discharged from the second pump <NUM>. The second cooling water passage <NUM> includes a first portion 20a, a second portion 20b, an engine cooling water jacket 20c (hereinafter referred to as a "water jacket 20c"), a third portion 20d, a fourth portion 20e, a fifth portion 20f, and a REC/REG cooling water jacket <NUM> (hereinafter referred to as a "water jacket <NUM>").

The first portion 20a, the exhaust manifold <NUM>, the second portion 20b, the water jacket 20c, the third portion 20d, the thermostat <NUM>, and the fourth portion 20e are sequentially disposed in this order from the water inlet 9a (upstream side) toward a water outlet 9c (downstream side).

The fifth portion 20f is branched into a portion that cools the fuel tank <NUM>, a water jacket <NUM>, and the heat exchanger <NUM>, the water jacket <NUM>, and the heat exchanger <NUM> downstream of a portion that cools the exhaust manifold <NUM>. The portion that cools the fuel tank <NUM>, the water jacket <NUM>, and the heat exchanger <NUM> are each connected to the fourth portion 20e.

When the rotation speed of the engine <NUM> decreases, the opening of the thermostat <NUM> gradually decreases as the temperature of the second cooling water L2 decreases, such that the flow rate of the second cooling water L2 that passes through the water jacket 20c gradually decreases. The fuel tank <NUM> is housed in the cowl <NUM>, and stores volatile fuel. The REC/REG <NUM> converts electric power generated based on driving of the engine <NUM> into a direct current of a predetermined voltage and outputs the direct current to the battery (not shown). The heat exchanger <NUM> cools engine oil that flows through an engine oil passage (not shown) with the second cooling water L2.

The flow of the first cooling water L1 and the flow of the second cooling water L2 are now described with reference to <FIG> and <FIG>. The first cooling water L1 is taken in via the water inlet 9a provided in the lower case <NUM>, and flows into the first pump <NUM>. Then, the first cooling water L1 pressurized and discharged by the first pump <NUM> is sent to the inverter water jacket 10b. Then, the first cooling water L1 flows into the converter water jacket 10d downstream of the inverter water jacket 10b. Thereafter, the first cooling water L1 is discharged via the water outlet 9b. Consequently, the first cooling water L1 flows through the inverter water jacket 10b such that the inverter <NUM> is cooled, and the first cooling water L1 flows through the converter water jacket 10d such that the converter <NUM> is cooled.

The second cooling water L2 is taken in via the water inlet 9a provided in the lower case <NUM>, and flows into the second pump <NUM>. Then, the second cooling water L2 pressurized and discharged by the second pump <NUM> is sent to the exhaust manifold <NUM>. Then, the second cooling water L2 flows through the water jacket 20c and the thermostat <NUM> in this order. Furthermore, the second cooling water L2 is sent to the fuel tank <NUM>, the water jacket <NUM>, and the heat exchanger <NUM> from the portion that cools the exhaust manifold <NUM>. Thereafter, the second cooling water L2 discharged from each of the thermostat <NUM>, the fuel tank <NUM>, the water jacket <NUM>, and the heat exchanger <NUM> is discharged via the water outlet 9c. Consequently, the engine <NUM>, the engine oil, the exhaust manifold <NUM>, and the fuel in the fuel tank <NUM> are cooled with the second cooling water L2.

According to the first preferred embodiment, the following advantageous effects are achieved.

According to the first preferred embodiment, the first pump <NUM> is an electric pump configured to pump the first cooling water L1 from the outside of the outboard motor body 101a and flow the first cooling water L1 into the first cooling water passage <NUM>. Accordingly, even while the engine <NUM> is stopped, the first pump <NUM> as an electric pump configured to pump the first cooling water L1 from the outside is driven by electric power. Therefore, even while the engine <NUM> is stopped, the first pump <NUM> is driven such that the converter <NUM> and the inverter <NUM> are cooled with the first cooling water L1.

According to the first preferred embodiment, the engine <NUM> is configured to rotate the drive shaft <NUM> connected to the propeller <NUM>. Furthermore, the outboard motor <NUM> includes the propulsion motor <NUM> configured to rotate the drive shaft <NUM>. In addition, the converter <NUM> and the inverter <NUM> are components of a power supply system configured to supply electric power to the propulsion motor <NUM>. Accordingly, even while the engine <NUM> is stopped, the first pump <NUM> is driven such that the converter <NUM> and the inverter <NUM> as components of a power supply system configured to supply electric power to the propulsion motor <NUM> are cooled with the first cooling water L1. Consequently, even when the hybrid technology of the engine <NUM> and the propulsion motor <NUM> is applied to the outboard motor <NUM>, electrical components (the converter <NUM> and the inverter <NUM>), for example, are effectively cooled.

According to the first preferred embodiment, the outboard motor <NUM> further includes the second cooling water passage <NUM> including the engine <NUM> etc., through which the second cooling water L2 passes, and the second pump <NUM> configured to flow the second cooling water L2 into the second cooling water passage <NUM>. Accordingly, the outboard motor <NUM> includes the first pump <NUM> and the second pump <NUM>, and thus unlike a case in which all the cooling targets are cooled by one pump, the cooling target (first cooling target) cooled by the first pump <NUM> and the cooling target (second cooling target) cooled by the second pump <NUM> are dispersed. Therefore, an increase in the size of each of the first pump <NUM> and the second pump <NUM> is significantly reduced or prevented. Consequently, the first pump <NUM> and the second pump <NUM>, in which increases in their sizes are significantly reduced or prevented, are dispersed and easily disposed in a limited space inside the outboard motor <NUM>.

According to the first preferred embodiment, the first pump <NUM> is configured to have a first cooling water L1 pumping capacity per unit time smaller than the second cooling water L2 pumping capacity per unit time of the second pump <NUM>. Accordingly, an increase in the size of the first pump <NUM> is further significantly reduced or prevented.

According to the first preferred embodiment, both the first pump <NUM> and the second pump <NUM> are positive-displacement pumps. Accordingly, both the first pump <NUM> and the second pump <NUM> easily pump water outside the outboard motor body 101a without priming the first pump <NUM> and the second pump <NUM>.

According to the first preferred embodiment, the first cooling water passage <NUM> and the second cooling water passage <NUM> include the common water inlet 9a through which the first cooling water L1 and the second cooling water L2 are taken in upstream of the inverter <NUM> and upstream of the engine <NUM>. Accordingly, the water inlet 9a through which the first cooling water L1 is taken in and the water inlet 9a through which the second cooling water L2 is taken in are shared, and thus the complex structure of the outboard motor <NUM> is significantly reduced or prevented.

According to the first preferred embodiment, the second pump <NUM> is an engine-driven pump configured to be driven by the drive shaft <NUM> when the engine <NUM> drives the drive shaft <NUM>. Accordingly, the flow rate of the second cooling water L2 that flows through the second cooling water passage <NUM> is increased according to an increase in the amount of heat generated by the engine <NUM>.

According to the first preferred embodiment, the outboard motor <NUM> includes the rotation speed detector 16a configured to detect the rotation speed of the propulsion motor <NUM>. Furthermore, driving of the first pump <NUM> is controlled based on the rotation speed of the propulsion motor <NUM> detected by the rotation speed detector 16a. Accordingly, the rotation speed of the propulsion motor <NUM> is detected such that the first pump <NUM> is driven as necessary. For example, when the propulsion motor <NUM> is being driven and the converter <NUM> and the inverter <NUM> are generating heat, the first pump <NUM> is effectively driven.

According to the first preferred embodiment, the first pump <NUM> is configured to be drivable while the engine <NUM> is stopped. Accordingly, the first pump <NUM> is driven while the engine <NUM> is stopped, and thus the converter <NUM> and the inverter <NUM> are cooled even while the engine <NUM> is stopped.

According to the first preferred embodiment, the first cooling water passage <NUM> includes the inverter water jacket 10b, which is a portion configured to cool the inverter <NUM>, upstream of the converter water jacket 10d, which is a portion configured to cool the converter <NUM>. Accordingly, the inverter <NUM> that generates more heat than the converter <NUM> is cooled in a relatively upstream portion of the first cooling water passage <NUM>. Consequently, the first cooling water L1 on the upstream side on which the temperature is lower than that on the downstream side effectively cools the inverter <NUM> that generates a large amount of heat.

According to the first preferred embodiment, the outboard motor <NUM> includes the temperature detector 16b configured to detect the temperature of the inverter <NUM>. Furthermore, driving of the first pump <NUM> is controlled based on the temperature detected by the temperature detector 16b. Accordingly, for example, when the temperature of the inverter <NUM> is abnormal, driving of the first pump <NUM> is limited. Consequently, driving of the first pump <NUM> in an abnormal state is significantly reduced or prevented.

According to the first preferred embodiment, the outboard motor <NUM> includes the water pressure detector 16c configured to detect the water pressure of the first cooling water L1 that flows through the first cooling water passage <NUM>. Furthermore, driving of the first pump <NUM> is stopped when the water pressure detected by the water pressure detector 16c is equal to or lower than the water pressure threshold. Accordingly, when there is a possibility that the first pump <NUM> is not operating normally, driving of the first pump <NUM> is stopped. Consequently, driving of the first pump <NUM> in an abnormal state is significantly reduced or prevented.

The structure of an outboard motor <NUM> of a marine vessel <NUM> according to a second preferred embodiment is now described with reference to <FIG>. In the second preferred embodiment, a propulsion motor <NUM> is cooled with first cooling water L1. In the second preferred embodiment, the same or similar structures as those of the first preferred embodiment are denoted by the same reference numerals, and description thereof is omitted. The propulsion motor <NUM> is an example of a "first cooling target".

As shown in <FIG>, the outboard motor <NUM> of the marine vessel <NUM> according to the second preferred embodiment includes a first cooling water passage <NUM>. In the outboard motor <NUM> according to the second preferred embodiment, the propulsion motor <NUM> is disposed in the first cooling water passage <NUM>, and the propulsion motor <NUM> is cooled with the first cooling water L1. Specifically, the first cooling water passage <NUM> includes a first portion 210a that connects a converter <NUM> to a portion that cools the propulsion motor <NUM>, and a second portion 210b that connects the portion that cools the propulsion motor <NUM> to a water outlet 9b. Thus, the first cooling water L1 is pumped from the outside of the outboard motor <NUM> by a first pump <NUM>, cools an inverter <NUM>, cools the converter <NUM>, cools the propulsion motor <NUM>, and is discharged to the outside of the outboard motor <NUM>. The remaining structures of the second preferred embodiment are similar to those of the first preferred embodiment.

According to the second preferred embodiment, the following advantageous effects are achieved.

According to the second preferred embodiment, in the outboard motor <NUM>, the propulsion motor <NUM> configured to rotate a drive shaft <NUM> is cooled with the first cooling water L1. Accordingly, even while an engine <NUM> is stopped, the propulsion motor <NUM> that generates heat when driven is cooled with the first cooling water L1 using the first pump <NUM>. The remaining advantageous effects of the second preferred embodiment are similar to those of the first preferred embodiment.

The structure of an outboard motor <NUM> of a marine vessel <NUM> according to a third preferred embodiment is now described with reference to <FIG>. In the third preferred embodiment, a fuel tank <NUM> and a REC/REG <NUM> are cooled with first cooling water L1. In the third preferred embodiment, the same or similar structures as those of the first preferred embodiment are denoted by the same reference numerals, and description thereof is omitted. The fuel tank <NUM> and the REC/REG <NUM> are examples of a "first cooling target".

As shown in <FIG>, the outboard motor <NUM> of the marine vessel <NUM> according to the third preferred embodiment includes a first cooling water passage <NUM> and a second cooling water passage <NUM>. The first cooling water passage <NUM> is disposed along the fuel tank <NUM> and the REC/REG <NUM>. That is, in the outboard motor <NUM>, a water jacket <NUM> that cools the fuel tank <NUM> and the REC/REG <NUM> is disposed in the first cooling water passage <NUM>, and fuel in the fuel tank <NUM> and the REC/REG <NUM> are cooled with the first cooling water L1.

Specifically, the first cooling water passage <NUM> includes a first portion 310a that connects a converter <NUM> to a portion that cools the fuel tank <NUM>, a second portion 310b that connects the fuel tank <NUM> to the water jacket <NUM>, and a third portion 310c that connects the water jacket <NUM> to a water outlet 9b. Thus, the first cooling water L1 is pumped from the outside of the outboard motor <NUM> by a first pump <NUM>, cools an inverter <NUM>, cools the converter <NUM>, cools the fuel in the fuel tank <NUM>, and cools the REC/REG <NUM>, and is discharged to the outside of the outboard motor <NUM>. The remaining structures of the third preferred embodiment are similar to those of the first preferred embodiment.

According to the third preferred embodiment, the following advantageous effects are achieved.

According to the third preferred embodiment, the first cooling water passage <NUM> is disposed along the fuel tank <NUM> such that the first cooling water L1 in the first cooling water passage <NUM> cools fuel in the fuel tank <NUM>. Accordingly, the temperature becomes high immediately after an engine <NUM> is stopped, and thus the fuel in the fuel tank <NUM>, which is preferably cooled even while the engine <NUM> is stopped, is cooled with the first cooling water L1. Consequently, even while the engine <NUM> is stopped, the fuel in the fuel tank <NUM> is cooled such that volatilization of the fuel is significantly reduced or prevented.

According to the third preferred embodiment, the first cooling water passage <NUM> is disposed along the REC/REG <NUM> such that the first cooling water L1 in the first cooling water passage <NUM> cools the REC/REG <NUM>. Accordingly, the REC/REG <NUM> is cooled even while the engine <NUM> is stopped. Consequently, even when the temperature of the REC/REG <NUM> is relatively high after the engine <NUM> is stopped, the REC/REG <NUM> is effectively cooled with the first cooling water L1. The remaining advantageous effects of the third preferred embodiment are similar to those of the first preferred embodiment.

The preferred embodiments described above are illustrative for present teaching but the present teaching also relates to modifications of the preferred embodiments.

For example, while examples of the first cooling target preferably include a converter, an inverter, a propulsion motor, a fuel tank, and a REC/REG in each of the first to third preferred embodiments described above, the present teaching is not restricted to this. For example, the first cooling target may alternatively include other components (such as an ECU and a battery).

While both the converter and the inverter are preferably cooled as the first cooling targets in each of the first to third preferred embodiments described above, the present teaching is not restricted to this. For example, only one of the converter and the inverter may alternatively be cooled as the first cooling target.

While the second pump is preferably an engine-driven pump in each of the first to third preferred embodiments described above, the present teaching is not restricted to this. For example, the second pump may alternatively be an electric pump.

While the cooling water pumping capacity per unit time of the first pump is preferably smaller than the cooling water pumping capacity per unit time of the second pump in each of the first to third preferred embodiments described above, the present teaching is not restricted to this. For example, the cooling water pumping capacity per unit time of the first pump may alternatively be equal to or larger than the cooling water pumping capacity per unit time of the second pump.

While the outboard motor preferably includes the common water inlet through which the first cooling water and the second cooling water are taken in in each of the first to third preferred embodiments described above, the present teaching is not restricted to this. For example, a water inlet through which the first cooling water is taken in and a water inlet through which the second cooling water is taken in may alternatively be separately provided. Alternatively, the common water inlet, the water inlet through which the first cooling water is taken in, or the water inlet through which the second cooling water is taken in may not be provided in the outboard motor but may be provided in the hull.

While the inverter water jacket is preferably provided upstream of the converter water jacket in each of the first to third preferred embodiments described above, the present teaching is not restricted to this. For example, the inverter water jacket may alternatively be provided downstream of the converter water jacket.

While both the first pump and the second pump are preferably positive-displacement pumps in each of the first to third preferred embodiments described above, the present teaching is not restricted to this. For example, at least one of the first pump and the second pump may alternatively be a non-positive displacement pump as long as the cooling water is pumped.

Claim 1:
An outboard motor (<NUM>, <NUM>, <NUM>) comprising:
an engine (<NUM>);
an electrical component (<NUM>, <NUM>) including a component of a power supply system including an inverter (<NUM>) and a converter (<NUM>);
a first cooling water passage (<NUM>, <NUM>, <NUM>) configured for first cooling water (L1) including water outside an outboard motor body (101a) to pass there through to cool a first cooling target (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) including the electrical component (<NUM>, <NUM>);
a first pump (<NUM>) that is an electric pump configured to pump the first cooling water (L1) from an outside of the outboard motor body (101a) and to pump the first cooling water (L1) into the first cooling water passage (<NUM>, <NUM>, <NUM>);
a second cooling water passage (<NUM>, <NUM>) configured for second cooling water (L2) to pass there through to cool a second cooling target (<NUM>, <NUM>) that is different from the first cooling target (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and includes the engine (<NUM>); and
a second pump (<NUM>) configured to pump the second cooling water (L2) into the second cooling water passage (<NUM>, <NUM>).