Patent Description:
An outboard motor including a rope reel is known in general. Such an outboard motor is disclosed in document <CIT> and <CIT>, for example.

<CIT> discloses an outboard motor including a rope reel including a rope winder around which a rope for starting an engine is wound. This outboard motor includes an accumulation power spring that accumulates the rotational force of the rope reel and transmits the rotational force to a crankshaft. In this outboard motor, the rope is pulled a plurality of times by an operator such that the rope reel rotates, and force is gradually accumulated in the accumulation power spring. Furthermore, in this outboard motor, when the force accumulated in the accumulation power spring exceeds a resistance on the compression stroke of the engine, a piston connected to the crankshaft moves beyond a top dead center, and the engine is started. That is, in this outboard motor, the rope is pulled (preliminary operation) in order to accumulate in advance force in the accumulation power spring before the engine is started such that a load required to pull the rope at the time of starting the engine is decreased.

However, in the outboard motor disclosed in <CIT>, before the engine is started, the preliminary operation is required to accumulate in advance at least a predetermined amount of force in the accumulation power spring. Thus, in the outboard motor disclosed in <CIT>, the work burden of starting the engine on the operator increases. In addition, in the outboard motor disclosed in <CIT>, a load is required to wind the accumulation power spring, and thus the total load including a load required to perform the preliminary operation and the load required to pull the rope at the time of starting the engine is larger than a load of the resistance on the compression stroke of the engine. Thus, also from this point, the work burden on the operator increases.

Therefore, in order to decrease the work burden of starting the engine, a motor that starts the engine with electric power in a battery is conceivably provided in the outboard motor without providing the accumulation power spring. Here, a general outboard motor includes a fuel injector and an ignition device that operate with electric power in a battery in order to start and drive an engine. Therefore, in the conventional outboard motor, it is necessary to ensure the amount of battery remaining at least enough to operate a fuel injector and an ignition device. In other words, in the conventional outboard motor (engine starting method), it is important to keep a close watch on the amount of battery remaining and maintain a state where the engine is reliably and quickly started. A similar motor has been disclosed in document <CIT>.

It is the object of the present invention to provide outboard motors and engine starting methods that maintain a state where an engine is reliably and quickly started while decreasing the work burden of starting the engine, and operate actuators related to fuel injection to start the engine even when the amount of battery remaining is not enough to assist an operator to start the engine. According to the present invention, said object is solved by an outboard motor having the features of independent claim <NUM>. Moreover, said object is also solved by an engine starting method having the features of independent claim <NUM>. Preferred embodiments are laid down in the dependent claims.

An outboard motor according to a preferred embodiment includes an engine including a crankshaft and that starts when the crankshaft is rotated at a cranking rotation speed or higher, a rope reel around which a rope is wound and connected to the crankshaft, a rotary electric machine connected to the crankshaft, and a rotary electric machine controller configured or programmed to control the rotary electric machine. The rotary electric machine controller is configured or programmed to, in a state where the crankshaft is rotated at a rotation speed within a cranking rotation speed range including the cranking rotation speed due to rotation of the rope reel, perform assist control of assisting rotation of the crankshaft by the rotary electric machine and perform power running rotation speed range expansion control of expanding a power running rotation speed range of the rotary electric machine. In this description, the expression "assisting by the rotary electric machine" means that in a state where the rope is pulled to rotate the rope reel and rotate the crankshaft, the rotary electric machine applies a rotational force to the crankshaft. The term "cranking" means that the crankshaft starts to rotate from a stopped state. The term "cranking rotation speed" means the lower limit of the rotation speed of the crankshaft at which initial explosion of the engine is possible. The term "initial explosion" means that the crankshaft starts to rotate from a stopped state, and fuel is initially burned. The term "power running rotation speed range" means a range of the rotation speed of the crankshaft within which electric power is supplied from a battery to the rotary electric machine.

In an outboard motor according to a preferred embodiment, the rotary electric machine controller is configured or programmed to perform the assist control of assisting rotation of the crankshaft by the rotary electric machine in a state where the crankshaft is rotated at the rotation speed within the cranking rotation speed range due to rotation of the rope reel. Accordingly, when an operator pulls the rope to rotate the rope reel, the rotary electric machine assists in rotation of the crankshaft, and thus a torque from the rotary electric machine is applied to the crankshaft, and a force (load) of pulling the rope required to exceed a resistance on the compression stroke of the engine is decreased. In addition, unlike the case where an accumulation power spring is provided, a preliminary operation of winding an accumulation power spring in advance is not necessary, and thus the work burden of starting the engine on the operator is decreased.

Here, in a general outboard motor, a force of pulling a rope may be relatively small depending on an operator when an engine is started by pulling the rope. In this case, the rotation speed of the crankshaft does not sufficiently increase, and the in-cylinder pressure of the engine may not be sufficiently achieved in order to generate initial explosion in the engine. In such a case, the operator needs to pull the rope a plurality of times. On the other hand, according to preferred embodiments, the rotary electric machine assists in rotation of the crankshaft such that even when the force of the operator to pull the rope is relatively small, the rotation speed of the crankshaft is increased. Consequently, the in-cylinder pressure of the engine is increased due to the increased rotation speed of the crankshaft, and thus the possibility that initial explosion occurs in the engine is increased, and the engine is more reliably started.

As described above, the rotary electric machine controller is configured or programmed to perform the power running rotation speed range expansion control of expanding the power running rotation speed range of the rotary electric machine in a state where the crankshaft is rotated at the rotation speed within the cranking rotation speed range. Accordingly, when the rotary electric machine is designed such that the induced voltage value of the rotary electric machine exceeds the output voltage value of the battery within the cranking rotation speed range, that is, even when the upper limit value of the cranking rotation speed range is larger than the upper limit value of the power running rotation speed range, the power running rotation speed range is expanded by the power running rotation speed range expansion control such that the rotary electric machine performs the power running operation. Consequently, when the power running rotation speed range expansion control is not performed, electric power is returned from the rotary electric machine to the battery within the cranking rotation speed range, and when the power running rotation speed range expansion control is performed, the induced voltage value is lowered below the output voltage value of the battery within the cranking rotation speed range, and the assist control is performed. Consequently, even when electric power is not supplied from the battery, the operator pulls the rope to rotate the rope reel and rotate the crankshaft at the rotation speed within the cranking rotation speed range such that using the electric power returned from the rotary electric machine, a fuel injector and an ignition device operate to start the engine. Therefore, a state where the engine is reliably and quickly started is maintained while the work burden of starting the engine is decreased. That is, even in the case of the amount of battery remaining not enough to assist the operator to start the engine, the actuators related to fuel injection operate to start the engine.

In an outboard motor according to a preferred embodiment, the rotary electric machine is preferably constructed such that a power generation rotation speed range, which is a range of the rotation speed of the crankshaft within which an induced voltage value is not less than an output voltage value of a battery, overlaps with the cranking rotation speed range in a state where the power running rotation speed range expansion control is not performed by the rotary electric machine controller, and the rotary electric machine controller is preferably configured or programmed to, in a state where the crankshaft is rotated at the rotation speed at least within the overlapping rotation speed range, perform the power running rotation speed range expansion control to lower the induced voltage value below the output voltage value and perform the assist control. Accordingly, when the crankshaft is rotated at the rotation speed within the overlapping rotation speed range, and the power running rotation speed range expansion control is not performed, electric power is returned from the rotary electric machine to the battery. When the crankshaft is rotated at the rotation speed within the overlapping rotation speed range, and the power running rotation speed range expansion control is performed, the assist control is easily performed.

In an outboard motor according to a preferred embodiment, the rotary electric machine controller is preferably configured or programmed to perform the assist control and the power running rotation speed range expansion control when a battery is in an assistable charge state. Accordingly, when the battery is charged with electric power, and the electric power of the battery is used to assist the operator to start the engine, the power running rotation speed range of the rotary electric machine is expanded by the power running rotation speed range expansion control such that the rotary electric machine assists in rotation of the crank shaft.

In this case, when the battery is not in the assistable charge state, and the crankshaft is rotated at the rotation speed within the cranking rotation speed range due to the rotation of the rope reel, electric power is preferably regenerated from the rotary electric machine. Accordingly, when the battery is not charged with electric power, and the assist control is not possible, the rope reel is rotated such that the crankshaft is rotated at the rotation speed within the cranking rotation speed range so as to regenerate and supply electric power to operate the fuel injector and the ignition device and further to charge the battery. That is, the rope reel is rotated such that the fuel injector etc. immediately operate with the regenerated electric power.

In a structure in which the assist control is performed when the battery is in the assistable charge state, the engine preferably includes an actuator related to fuel injection, the outboard motor preferably further includes a drive controller configured or programmed to control driving of the actuator, and when the battery is not in the assistable charge state, and the crankshaft is rotated at the rotation speed within the cranking rotation speed range due to the rotation of the rope reel, electric power is preferably supplied from the rotary electric machine to the actuator and the drive controller. Accordingly, even when the battery is not in the assistable charge state, the actuator and the drive controller are driven with the electric power regenerated from the rotary electric machine to start the engine.

In a structure in which the assist control is performed when the battery is in the assistable charge state, the rotary electric machine controller is preferably configured or programmed to be activated with electric power from the rotary electric machine when the battery is not in the assistable charge state, and the crankshaft is rotated at the rotation speed within the cranking rotation speed range due to the rotation of the rope reel. Accordingly, even when the battery is not in the assistable charge state, the rope reel is rotated to activate the rotary electric machine controller. Consequently, even when the battery is not in the assistable charge state, the rotary electric machine controller is activated to appropriately control the operation of the rotary electric machine.

In a structure in which the assist control is performed when the battery is in the assistable charge state, the rotary electric machine controller is preferably configured or programmed to perform the assist control and the power running rotation speed range expansion control when a value of a voltage applied from the battery is equal to or larger than a predetermined voltage value as when the battery is in the assistable charge state. Accordingly, the value of the voltage applied from the battery is compared with the predetermined voltage value such that it is easily determined whether or not the battery is in the assistable charge state, and when the battery is sufficiently charged with electric power, the assist control is performed.

In an outboard motor according to a preferred embodiment, the rotary electric machine controller is preferably configured or programmed to start the power running rotation speed range expansion control upon change of the rotation speed of the crankshaft from less than a first rotation speed to not less than the first rotation speed within the cranking rotation speed range when performing the assist control. Here, when the rotation speed of the crankshaft is relatively low (less than the first rotation speed), the induced voltage value generated in the rotary electric machine becomes relatively small, and thus a torque generated by the rotary electric machine when the power running rotation speed range expansion control is not performed becomes larger than a torque generated by the rotary electric machine when the power running rotation speed range expansion control is performed. In view of this point, according to preferred embodiments, the power running rotation speed range expansion control is started upon change of the rotation speed of the crankshaft from less than the first rotation speed to not less than the first rotation speed, and thus when the rotation speed of the crankshaft is less than the first rotation speed, the rotary electric machine is rotated to increase a torque without performing the power running rotation speed range expansion control, and when the rotation speed is not less than the first rotation speed such that the torque is decreased due to an increased induced voltage value, the rotary electric machine is rotated to increase the torque with performing the power running rotation speed range expansion control. Consequently, even when the crankshaft is rotated at any rotation speed, the torque is increased, and thus the rotary electric machine efficiently assists in rotation of the crankshaft.

In an outboard motor according to a preferred embodiment, the rotary electric machine controller is preferably configured or programmed to, when performing the assist control, perform advance angle control on the rotary electric machine in the state where the crankshaft is rotated at the rotation speed within the cranking rotation speed range so as to perform the power running rotation speed range expansion control to lower an induced voltage value of the rotary electric machine. Accordingly, the induced voltage value of the rotary electric machine is lowered in response to a change in the conduction phase of electric power to be supplied to the rotary electric machine, and thus the power running rotation speed range is easily expanded.

In this case, the rotary electric machine controller is preferably configured or programmed to, when performing the assist control, perform control of switching a conduction phase to the rotary electric machine from a first phase angle to a second phase angle larger than the first phase angle in the state where the crankshaft is rotated at the rotation speed within the cranking rotation speed range so as to perform the power running rotation speed range expansion control to lower the induced voltage value. Accordingly, the conduction phase to the rotary electric machine is switched such that the induced voltage value is lowered. Therefore, the conduction phase to the rotary electric machine is advanced (switched) from the first phase angle to the second phase angle such that the power running rotation speed range expansion control is easily performed.

In an outboard motor according to a preferred embodiment, the rotary electric machine preferably rotates with three-phase alternating current power supplied to the rotary electric machine, and the rotary electric machine controller is preferably configured or programmed to perform the assist control while supplying the three-phase alternating current power having a first conduction period of more than <NUM> electrical degrees to the rotary electric machine in the state where the crankshaft is rotated at the rotation speed within the cranking rotation speed range. Accordingly, the power running rotation speed range is further expanded.

In this case, the rotary electric machine controller is preferably configured or programmed to perform the assist control while supplying the three-phase alternating current power having a second conduction period of not more than <NUM> electrical degrees to the rotary electric machine in a state where the crankshaft is rotated at the rotation speed less than a second rotation speed within the cranking rotation speed range, and is preferably configured or programmed to perform the assist control while supplying the three-phase alternating current power having the first conduction period to the rotary electric machine in a state where the crankshaft is rotated at the rotation speed not less than the second rotation speed within the cranking rotation speed range. Accordingly, when the crankshaft is rotated at the rotation speed less than the second rotation speed at which the induced voltage value is relatively small, the conduction period is set to <NUM> electrical degrees or less such that more efficient assist control is performed, and when the crankshaft is rotated at the rotation speed not less than the second rotation speed at which the induced voltage value is relatively large, the conduction period is changed to the first conduction period such that the power running rotation speed range is expanded, and the assist control is performed while significantly reducing or preventing a decrease in torque.

In an outboard motor according to a preferred embodiment, the rotary electric machine controller is preferably configured or programmed to, in a state where the crankshaft is rotated at the rotation speed larger than the cranking rotation speed range, stop the power running rotation speed range expansion control and perform power generation control. Accordingly, when the engine is started and the crankshaft is rotated at the rotation speed larger than the cranking rotation speed range, the output voltage value of the battery is constant, and thus electric power is appropriately supplied to engine auxiliaries including the fuel injector and the ignition device while the battery is charged.

An outboard motor according to a preferred embodiment preferably further includes a rotation angle acquirer that acquires a rotation angle of the rotary electric machine. Accordingly, the rotation angle necessary for conduction control of the rotary electric machine and detected by the rotation angle acquirer is diverted to the power running rotation speed range expansion control and the assist control. Consequently, it is not necessary for the operator to perform an input operation when the assist control is started, and thus an operation of starting the engine becomes simpler.

In an outboard motor according to a preferred embodiment, the rotary electric machine controller is preferably configured or programmed to, after the rotation speed of the crankshaft exceeds a rotation speed of the rope reel, continue to perform the power running rotation speed range expansion control and perform control of supplying electric power from a battery to the rotary electric machine to rotate the crankshaft. Here, as described above, in a general outboard motor, in the first compression stroke of an engine, initial explosion may not be reached, and the engine is not likely to start. Therefore, in a general outboard motor, the length of a rope is relatively increased such that the compression stroke of the engine is reached a plurality of times while the rope is pulled once, and in any of the reached compression strokes, initial explosion is caused to occur. On the other hand, according to preferred embodiments, the rotary electric machine controller is configured or programmed to, after the rotation speed of the crankshaft exceeds the rotation speed of the rope reel, continue to perform the power running rotation speed range expansion control and perform control of rotating the crankshaft, and thus even when the operator cannot perform a cranking operation enough to start the engine, the engine is started while the crankshaft is continuously rotated by the rotary electric machine. Consequently, the length of the rope is decreased.

In an outboard motor according to a preferred embodiment, the engine preferably includes a fuel injector and an ignition device, and the rotary electric machine controller is preferably configured or programmed to, at least until fuel injection by the fuel injector is completed and initial ignition by the ignition device is completed, continue to perform the power running rotation speed range expansion control and perform control of supplying electric power from a battery to the rotary electric machine in the state where the crankshaft is rotated at the rotation speed within the cranking rotation speed range. Accordingly, the rotary electric machine assists in rotation of the crankshaft at least until ignition is performed in the engine, and thus the engine is more reliably started.

In an outboard motor according to a preferred embodiment, the rotary electric machine preferably includes a rotor directly connected to the crankshaft and a stator that faces the rotor in a radial direction of the crankshaft. Accordingly, unlike the case where the rotor of the rotary electric machine and the crankshaft are not directly connected to each other, as the case where a gear or the like is provided between the rotary electric machine and the crankshaft, complication of the configuration of the outboard motor is significantly reduced or prevented. Furthermore, with the above configuration, an existing rotary electric machine provided in a general outboard motor is usable as the rotary electric machine that assists in rotation of the crankshaft.

An outboard motor according to a preferred embodiment preferably further includes a battery disposed in an outboard motor body, that supplies electric power to the rotary electric machine, and to which the electric power is returned from the rotary electric machine. Accordingly, there is no need to provide a power line through which electric power is exchanged between a marine vessel (vessel body) and the outboard motor unlike the case where electric power is supplied from the battery provided in the marine vessel to the rotary electric machine. Consequently, the configuration that connects the outboard motor to the marine vessel is simplified.

An engine starting method according to a preferred embodiment is an engine starting method for an engine that starts when a crankshaft is rotated at a cranking rotation speed or higher, and includes rotating the crankshaft by a manual starter connected to the crankshaft, and performing assist control of assisting rotation of the crankshaft by a rotary electric machine connected to the crankshaft and performing power running rotation speed range expansion control of expanding a power running rotation speed range of the rotary electric machine in a state where the crankshaft is rotated at a rotation speed within a cranking rotation speed range including the cranking rotation speed by the manual starter.

An engine starting method according to a preferred embodiment is adapted as described above such that the engine starting method maintains a state where the engine is reliably and quickly started while decreasing the work burden of starting the engine. In addition, the engine starting method operates an actuator related to fuel injection to start the engine even in the case of the amount of battery remaining not enough to assist an operator to start the engine.

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 an outboard motor <NUM> according to preferred embodiments is now described with reference to <FIG>. In the following description, the term "front" or "forward movement direction" represents a direction FWD in <FIG>, and the term "rear" or "rearward movement direction" represents a direction BWD in <FIG>.

As shown in <FIG>, the outboard motor <NUM> is attached to a rear portion of a vessel body <NUM>. The outboard motor <NUM> includes an engine <NUM>, a puller <NUM>, a tiller handle <NUM>, a drive shaft <NUM>, a gear <NUM>, a propeller shaft <NUM>, a propeller <NUM>, and a bracket <NUM>. The outboard motor <NUM> is attached to the vessel body <NUM> by the bracket <NUM>.

As shown in <FIG>, the outboard motor <NUM> includes a cowling 9a and a case 9b provided below the cowling 9a. The engine <NUM> is housed in the cowling 9a. The puller <NUM> protrudes from the cowling 9a in the forward movement direction. The tiller handle <NUM> protrudes from the cowling 9a in the forward movement direction below (on the arrow Z2 direction side of) the puller <NUM>. The drive shaft <NUM>, the gear <NUM>, and the propeller shaft <NUM> are disposed inside the case 9b. The propeller <NUM> is disposed on the lower side inside the case 9b. The bracket <NUM> is disposed on the forward movement direction side of the case 9b. The cowling 9a and the case 9b are examples of an "outboard motor body".

The engine <NUM> is an internal combustion engine driven by explosive combustion of gasoline, light oil, or the like. For example, the engine <NUM> is a four-stroke engine that repeats an exhaust stroke, an intake stroke, a compression stroke, and an expansion stroke.

As shown in <FIG>, the engine <NUM> includes a plurality of cylinders <NUM> aligned in an upward-downward direction (direction Z), pistons <NUM> that horizontally reciprocate in the cylinders <NUM>, respectively, connecting rods <NUM> connected to the pistons <NUM>, and a crankshaft <NUM> connected to the connecting rods <NUM> and that extends in the upward-downward direction. The horizontal reciprocating movement of the pistons <NUM> is converted into a rotational motion by the connecting rods <NUM> and the crankshaft <NUM>. The lower end of the crankshaft <NUM> is connected to the drive shaft <NUM> (see <FIG>). The upper end of the crankshaft <NUM> is connected to a flywheel magneto <NUM> (hereinafter referred to as the "FWM <NUM>") that stabilizes rotation of the engine <NUM>. The FWM <NUM> is an example of a "rotor".

As shown in <FIG>, the engine <NUM> includes engine auxiliaries 1a. The engine auxiliaries 1a include actuators related to fuel injection (FI). For example, the engine auxiliaries 1a include a fuel injector <NUM>, an ignition device <NUM>, etc. In the engine <NUM>, based on commands from an ECU <NUM> described below, for example, fuel is injected by the fuel injector <NUM> during the exhaust stroke, mixed gas of the injected fuel and air is introduced into the cylinders <NUM> during the intake stroke, the introduced fuel is ignited and burned by the ignition device <NUM> during the compression stroke, and the pistons <NUM> in the cylinders <NUM> move during the expansion stroke (see <FIG>). The fuel injector <NUM> and the ignition device <NUM> operate using electric power supplied from a battery <NUM> or electric power regenerated (returned) from a rotary electric machine <NUM>. The fuel injector <NUM> and the ignition device <NUM> are examples of an "actuator related to fuel injection". The actuator related to FI includes a fuel pump, an injector, and an idle speed control (ISC) motor, for example.

As shown in <FIG>, inside the cowling 9a of the outboard motor <NUM>, a manual starter <NUM> that manually starts the engine <NUM> is disposed above the FWM <NUM> of the engine <NUM>. The manual starter <NUM> is connected to the crankshaft <NUM> and rotates the crankshaft <NUM> by human power. In other words, the manual starter <NUM> is a recoil starter and is a pull starter.

Specifically, the manual starter <NUM> includes a rope reel <NUM> rotatable around a rotation center axis C (hereinafter referred to as the "axis C") of the crankshaft <NUM>, and a rope <NUM>, one end of which is connected to the rope reel <NUM> and the other end of which is connected to the puller <NUM>, and wound around the rope reel <NUM>. The puller <NUM> is pulled by an operator such that the rope reel <NUM> is rotated around the axis C.

As shown in <FIG>, the manual starter <NUM> includes a cam plate <NUM> rotatable around the axis C. The cam plate <NUM> includes an engagement pawl 23b rotatable around a rotation shaft 23a. A cylindrical protrusion 15b is provided on an upper portion (portion in an arrow Z1 direction) of the FWM <NUM>, and a plurality of engagement recesses 15c are provided on the inner surface of the protrusion 15b. When the engine <NUM> is manually started, the engagement pawl 23b is caught in the engagement recesses 15c such that the rotational force of the manual starter <NUM> (rope reel <NUM>) is transmitted to the FWM <NUM>. The rotational force is transmitted from the FWM <NUM> to the crankshaft <NUM>, and the crankshaft <NUM> rotates such that the pistons <NUM> horizontally move via the connecting rods <NUM>.

The manual starter <NUM> is constructed such that when the rotation speed of the FWM <NUM> (crankshaft <NUM>) exceeds the rotation speed of the rope reel <NUM>, the engagement pawl 23b and the engagement recesses 15c disengage from each other, and torque transmission between the FWM <NUM> and the rope reel <NUM> is stopped. When the operation of pulling the rope <NUM> is stopped, or when the engine <NUM> is started and the rotation speed of the crankshaft <NUM> increases, for example, torque transmission from the rope reel <NUM> to the FWM <NUM> is stopped.

As shown in <FIG>, the outboard motor <NUM> (the cowling 9a or the case 9b) includes the rotary electric machine <NUM>, an inverter with a built-in controller (ECU: Engine Control Unit) <NUM> (hereinafter referred to as the "ECU <NUM>"), the battery <NUM>, and a crank sensor 14a. The ECU <NUM> is an example of a "rotary electric machine controller" or a "drive controller".

As requirements of an engine control crank signal, it is necessary to detect a reference angle once per rotation of the crankshaft <NUM> (FWM <NUM>), and a predetermined angular resolution (<NUM> degrees, for example) is required to determine a crank angle. For example, the crank sensor 14a detects a protrusion (not shown) provided on the outer periphery of a rotor (FWM <NUM>) of the rotary electric machine <NUM>. Specifically, one protrusion is provided on the outer periphery of the rotor, and in the outboard motor <NUM>, a low-level signal is output from the crank sensor 14a that has been detected the protrusion (see <FIG>). That is, the crank sensor 14a outputs a low-level signal once per rotation of the FWM <NUM>. A rotation angle sensor <NUM> described below has the predetermined angular resolution (<NUM> degrees, for example) enough to determine the crank angle, and thus a signal from the crank sensor 14a and a signal from the rotation angle sensor <NUM> are combined such that the ECU <NUM> controls the engine <NUM>. The crank sensor 14a is provided in the engine <NUM>.

As shown in <FIG>, the rotary electric machine <NUM> includes the FWM <NUM>, on which a plurality of permanent magnets <NUM> are disposed, directly connected to the crankshaft <NUM>, and stators <NUM> (winding) that face the permanent magnets <NUM> in the radial direction of the crankshaft <NUM>. The permanent magnets <NUM> are fixed to the inner peripheral surface of the FWM <NUM>, for example. As shown in <FIG>, the rotary electric machine <NUM> includes the rotation angle sensor <NUM>, acquires a change in the rotation angle of the FWM <NUM> (permanent magnets <NUM>), and transmits the change to a control circuit <NUM> of the ECU <NUM>. The rotation angle sensor <NUM> includes a Hall element, for example, and has the predetermined angular resolution (<NUM> degrees, for example). The rotation angle sensor <NUM> is an example of a "rotation angle acquirer".

As shown in <FIG>, the rotary electric machine <NUM> functions as a generator that returns an induced voltage generated by rotation of the FWM <NUM> to the battery <NUM>, and functions as a motor that rotates with electric power supplied from the battery <NUM> to rotate the crankshaft <NUM>. For example, three-phase (U phase, V phase, and W phase) alternating current power is supplied to the rotary electric machine <NUM> such that the rotary electric machine <NUM> rotates. That is, the rotary electric machine <NUM> is configured as an integrated starter generator (ISG).

Specifically, the rotary electric machine <NUM> is constructed such that a power generation rotation speed range Rg, which is a range of the rotation speed N of the crankshaft <NUM> within which an induced voltage value Vi is not less than the output voltage value Vb of the battery <NUM>, overlaps with a cranking rotation speed range Rc in a state where power running rotation speed range expansion control of expanding a power running rotation speed range Rd of the rotary electric machine <NUM> is not performed by the ECU <NUM>. In other words, the rotation speed N of the crankshaft <NUM> is an engine rotation speed. The "power running rotation speed range expansion control" is described below in detail.

Specifically, the cranking rotation speed range Rc is a range of the rotation speed N of the crankshaft <NUM> when the engine <NUM> is cranked. That is, the cranking rotation speed range Rc includes an initial explosion generation rotation speed range Re, which is a range of the rotation speed N of the crankshaft <NUM> within which initial explosion is possible in the engine <NUM>. The initial explosion generation rotation speed range Re is a range from a lower limit rotation speed N1a to an upper limit rotation speed N1b, for example. Furthermore, an idling rotation speed Na, which is the rotation speed N of the crankshaft <NUM> during the idling operation of the engine <NUM>, is higher than the rotation speed N1b. Note that the term "cranking" means that the crankshaft <NUM> starts to rotate from a stopped state. The lower limit rotation speed N1a of the initial explosion generation rotation speed range Re is an example of a "cranking rotation speed".

In the rotary electric machine <NUM>, the induced voltage value Vi increases as the rotation speed N increases. The rotary electric machine <NUM> is constructed such that the output voltage value Vb of the battery <NUM> and the induced voltage value Vi are substantially equal to each other when the rotation speed N of the crankshaft <NUM> is N2. The rotation speed N2 is a range of not less than the rotation speed N1a and not more than the rotation speed N1b.

When the rotation speed N of the crankshaft <NUM> is higher than N2 (power generation rotation speed range Rg) in a state where the power running rotation speed range expansion control described below is not performed and control at a first phase angle (<NUM> degrees) with <NUM>-degree conduction is performed (hereinafter referred to as the "conduction regeneration control"), the induced voltage value Vi becomes larger than the output voltage value Vb of the battery <NUM>, and electric power from the rotary electric machine <NUM> is returned to the battery <NUM>. That is, the rotary electric machine <NUM> has characteristics that the cranking rotation speed range Rc and the power generation rotation speed range Rg overlap with each other in a rotation speed range of not less than the rotation speed N2 and not more than the rotation speed N1b.

When the rotation speed N of the crankshaft <NUM> is higher than N3 (power generation rotation speed range Rg) in a state where the power running rotation speed range expansion control is not performed and the switching operation is not performed by switching elements <NUM> but body diodes on the switching elements <NUM> perform rectification (hereinafter referred to as the "full-wave rectification state"), the induced voltage value Vi becomes larger than the output voltage value Vb of the battery <NUM>, and electric power from the rotary electric machine <NUM> is returned to the battery <NUM>. That is, the rotary electric machine <NUM> has characteristics that the cranking rotation speed range Rc and the power generation rotation speed range Rg overlap with each other in a rotation speed range of not less than the rotation speed N3 and not more than the rotation speed N1b. For example, the rotation speed N3 is higher than the rotation speed N2.

As shown in <FIG>, the outboard motor <NUM> includes a main switch <NUM> provided between the ECU <NUM> and the battery <NUM> and a start switch <NUM> provided between the main switch <NUM> and the ECU <NUM>. When the operation of the outboard motor <NUM> is started, for example, the main switch <NUM> is turned on (conducts), and a power supply terminal 40a of the ECU <NUM> and the battery <NUM> are connected to each other. When the main switch <NUM> is turned on, electric power is supplied from the battery <NUM> to the engine auxiliaries 1a of the engine <NUM>.

In the outboard motor <NUM>, when the battery <NUM> is not in an assistable charge state, and the crankshaft <NUM> is rotated at the rotation speed N within the cranking rotation speed range Rc due to rotation of the rope reel <NUM>, electric power from the rotary electric machine <NUM> is supplied to the fuel injector <NUM> and the ECU <NUM>. That is, when the outboard motor <NUM> is in a charge state where the conduction regeneration control is possible, the ECU <NUM> supplies the electric power from the rotary electric machine <NUM> to the engine auxiliaries 1a by the conduction regeneration control. When the outboard motor <NUM> is not in the charge state where the conduction regeneration control is possible, the ECU <NUM> is in the full-wave rectification state, and the electric power from the rotary electric machine <NUM> is supplied to the engine auxiliaries 1a and the ECU <NUM>. For example, in the outboard motor <NUM>, the electric power from the rotary electric machine <NUM> is supplied to the fuel injector <NUM> in the engine <NUM> via a start relay <NUM> described below.

When the start switch <NUM> is turned on, a start switch signal is input to a start terminal 40b of the ECU <NUM>. When the start switch signal is input and the ECU <NUM> acquires a change in the rotation angle from the rotation angle sensor <NUM>, the ECU <NUM> performs assist control (and the power running rotation speed range expansion control).

The outboard motor <NUM> includes a main relay <NUM> provided between the ECU <NUM> and the battery <NUM>, the start relay <NUM> provided between the main switch <NUM> and the ECU <NUM>, the start switch <NUM> provided between the main relay <NUM> and the ECU <NUM>, and a protective component <NUM>.

The ECU <NUM> includes a switch 43a that switches between a state where an exciting coil of the main relay <NUM> is grounded and a state where the exciting coil is not grounded, and a switch 43b that switches between a state where an exciting coil of the start relay <NUM> is grounded and a state where the exciting coil is not grounded. The switches 43a and 43b operate based on commands from the control circuit <NUM>.

As shown in <FIG>, the ECU <NUM> includes a plurality of switching elements <NUM> and the control circuit <NUM> that controls the operations of the plurality of switching elements <NUM>. Furthermore, the ECU <NUM> is connected to the rotary electric machine <NUM> by a three-phase (U phase, V phase, and W phase) power line <NUM> and is connected to the battery <NUM> by a power line <NUM>.

The switching elements <NUM> each include a field effect transistor (FET), for example. Preferably, each of the switching elements <NUM> is an N-channel MOSFET with a body diode. The control circuit <NUM> performs control of performing switching operation (of switching between the conduction state (ON) and the disconnection state (OFF) of each of the three phases) by transmitting gate drive signals to the plurality of switching elements <NUM>.

The control circuit <NUM> acquires information about the rotation angle from the rotation angle sensor <NUM> and controls the operations of the switching elements <NUM> based on the acquired information about the rotation angle. Specifically, the control circuit <NUM> sets U-phase, V-phase, and W-phase conduction periods (<NUM>-degree conduction or <NUM>-degree conduction, for example) in synchronization with the acquired rotation angle, and performs advance angle control of setting a conduction phase to the rotary electric machine <NUM>. When the switching elements <NUM> do not operate, the full-wave rectification state is established. As shown in <FIG>, the control circuit <NUM> acquires information about the crank angle from the crank sensor 14a and controls the operations of the fuel injector <NUM> and the ignition device <NUM> based on the acquired information about the crank angle. The <NUM>-degree conduction is an example of a "first conduction period". The <NUM>-degree conduction is an example of a "second conduction period". The conduction phase is a phase difference between the phase of the induced voltage and the phase of the conduction voltage.

Specifically, as shown in <FIG>, the control circuit <NUM> includes an assist control/power generation control switching determiner 42a (hereinafter referred to as the "switching determiner 42a"), a crank angle calculator 42b, an engine control mode determiner 42c (hereinafter referred to as the "mode determiner 42c"), an ignition/fuel injection controller 42d, an electrical angle calculator 42e, a conduction controller 42f, and an engine stop controller <NUM>.

The switching determiner 42a acquires the information about a change in the rotation angle from the rotation angle sensor <NUM> and the information from the crank sensor 14a to acquire the rotation speed N of the crankshaft <NUM> and switches the conduction phase or the conduction system based on the acquired rotation speed N. Commands from the switching determiner 42a are input to the conduction controller 42f.

As shown in <FIG>, the switching determiner 42a determines whether or not to perform assist control of assisting rotation of the crankshaft <NUM> by the rotary electric machine <NUM> upon detection of a change in the output state of the rotation angle sensor <NUM> due to change from a state where the crankshaft <NUM> stops to a state where the crankshaft <NUM> rotates. According to preferred embodiments, the expression "assisting by the rotary electric machine <NUM>" means that in a state where the operator pulls the rope <NUM> to rotate the rope reel <NUM> and rotate the crankshaft <NUM>, the rotary electric machine <NUM> inputs a rotational force to the crankshaft <NUM>. The "assist control" is described below in detail.

Specifically, when the battery <NUM> is in the assistable charge state, the switching determiner 42a performs the assist control of assisting rotation of the crankshaft <NUM> by the rotary electric machine <NUM> in a state where the crankshaft <NUM> is rotated at the rotation speed N within the cranking rotation speed range Rc due to rotation of the rope reel <NUM>, and when the battery <NUM> is not in the assistable charge state, the switching determiner 42a does not perform the assist control.

Here, the switching determiner 42a performs the assist control when the output voltage value Vb applied from the battery <NUM> is equal to or more than a reference voltage value Vt when the battery <NUM> is in the assistable charge state. For example, as shown in <FIG>, the switching determiner 42a compares the output voltage value Vb of the battery <NUM> applied from the battery <NUM> to the power supply terminal 40a via the main switch <NUM> with the reference voltage value Vt. The switching determiner 42a starts the assist control when the output voltage value Vb is equal to or more than the reference voltage value Vt, and does not perform the assist control when the output voltage value Vb is less than the reference voltage value Vt. The reference voltage value Vt is an example of a "predetermined voltage value".

As shown in <FIG>, the switching determiner 42a starts the power running rotation speed range expansion control when the switching determiner 42a performs the assist control, and the rotation speed N of the crankshaft <NUM> changes from less than a predetermined switching rotation speed Nt to not less than the switching rotation speed Nt. The switching rotation speed Nt is set as a rotation speed at which the magnitude of a torque generated when the power running rotation speed range expansion control is performed is equal to or larger than the magnitude of a torque generated when the power running rotation speed range expansion control is not performed, for example. The switching rotation speed Nt is an example of a "first rotation speed" or a "second rotation speed".

That is, in a state where the rotation speed N of the crankshaft <NUM> is at least the rotation speed N2 (rotation speed N3) and not more than the rotation speed N1b, which is a rotation speed within the rotation speed range where the cranking rotation speed range Rc and the power generation rotation speed range Rg overlap with each other, the switching determiner 42a performs the power running rotation speed range expansion control (two-dot chain line) to lower the induced voltage value Vi below the output voltage value Vb and performs the assist control.

Regardless of whether or not the operator continues to pull the rope <NUM>, the switching determiner 42a continues to perform the power running rotation speed range expansion control and perform control of supplying electric power from the battery <NUM> to the rotary electric machine <NUM> to rotate the crankshaft <NUM>.

That is, even after the rotation speed N of the crankshaft <NUM> exceeds the rotation speed of the rope reel <NUM>, the switching determiner 42a continues to perform the power running rotation speed range expansion control and perform control of supplying electric power from the battery <NUM> to the rotary electric machine <NUM> to rotate the crankshaft <NUM>. In other words, as shown in <FIG>, even after the rope <NUM> is pulled (stroked) and a torque input to the crankshaft <NUM> via the rope reel <NUM> is stopped, the switching determiner 42a continues to perform the power running rotation speed range expansion control and perform control of supplying electric power from the battery <NUM> to the rotary electric machine <NUM> to rotate the crankshaft <NUM>.

According to preferred embodiments, in a state where the crankshaft <NUM> is rotated at the rotation speed N (the idling rotation speed Na, for example) larger than the cranking rotation speed range Rc, the switching determiner 42a stops the power running rotation speed range expansion control and performs power generation control (one-dot chain line in <FIG>). The power generation control is described below in detail.

As shown in <FIG>, the crank angle calculator 42b acquires information from the crank sensor 14a and the rotation angle sensor <NUM>, calculates the crank angle and the rotation speed (rotation number) of the crankshaft <NUM>, and transmits the calculated crank angle and speed to the mode determiner 42c.

The mode determiner 42c determines control to be performed on the fuel injector <NUM> and the ignition device <NUM> included in the engine <NUM> based on the information acquired from the crank angle calculator 42b. The mode determiner 42c determines an engine control mode and transmits information about the determined mode to the ignition/fuel injection controller 42d. The ignition/fuel injection controller 42d determines the fuel injection timing of the fuel injector <NUM>, the ignition timing of the ignition device <NUM>, and the like based on the information about the mode and the like. The ignition/fuel injection controller 42d is an example of a "drive controller".

When a state where there is no input (edge input) from the rotation angle sensor <NUM> continues for a predetermined time or more, for example, the mode determiner 42c sets the engine control mode to an "engine stop mode". In the "engine stop mode", the ignition/fuel injection controller 42d controls the engine <NUM> to be stopped.

When acquiring a change in the rotation angle (edge input) from the rotation angle sensor <NUM> in the "engine stop mode", the ignition/fuel injection controller 42d starts to control the fuel injector <NUM> to inject fuel (first injection execution period) asynchronously with the operation of the crankshaft <NUM>. When acquiring an edge input from the crank sensor 14a, the ignition/fuel injection controller 42d starts an ignition execution period, which is a period during which the ignition device <NUM> performs ignition.

When the rotation speed N is equal to or higher than a predetermined rotation speed Ni, the mode determiner 42c sets the engine control mode to a "post-initial explosion completion mode". The ignition/fuel injection controller 42d starts to control the fuel injector <NUM> to inject fuel (second injection execution period) synchronously with the operation of the crankshaft <NUM> in the "post-initial explosion completion mode". The predetermined rotation speed Ni is a rotation speed within or above the cranking rotation speed range Rc and equal to or less than the idling rotation speed Na, for example.

The electrical angle calculator 42e acquires the information about the rotation angle from the rotation angle sensor <NUM> and calculates an electrical angle for conduction control. The electrical angle calculator 42e transmits the calculated electrical angle to the conduction controller 42f.

The conduction controller 42f controls the drive voltage, conduction system, conduction phase of each of the switching elements <NUM> based on commands from the switching determiner 42a. The engine stop controller <NUM> stops (prohibits) the operations of the fuel injector <NUM> and the ignition device <NUM> when a stop operation (a stop flag, abnormality detection, or the like) is input. Furthermore, the engine stop controller <NUM> transmits a command signal that indicates switching between a conduction state and a non-conduction state to the conduction controller 42f.

Here, the assist control means that the operations of the switching elements <NUM> are controlled by the ECU <NUM> such that electric power is supplied from the battery <NUM> to the rotary electric machine <NUM>. In other words, the assist control means controlling the rotary electric machine <NUM> to rotate the crankshaft <NUM> within the power running rotation speed range Rd (a range of power running operation) and within the cranking rotation speed range Rc (within a dotted line region) shown in <FIG> when the engine <NUM> is started.

Even when the rotation speed N is equal to or higher than the rotation speed N2, the ECU <NUM> performs the power running rotation speed range expansion control of expanding the power running rotation speed range Rd in order to perform the assist control (power running operation). Specifically, when performing the assist control, the control circuit <NUM> performs the advance angle control on the rotary electric machine <NUM> in a state where the crankshaft <NUM> is rotated at the rotation speed N within the cranking rotation speed range Rc to lower the induced voltage value Vi and expand the power running rotation speed range Rd. That is, the advance angle control is used as a means that performs field weakening control to lower the induced voltage value Vi.

More specifically, when performing the assist control, the ECU <NUM> performs the advance angle control of switching the conduction phase to the rotary electric machine <NUM> from the first phase angle to a second phase angle larger than the first phase angle in a state where the crankshaft <NUM> is rotated at the rotation speed within the cranking rotation speed range Rc so as to perform the power running rotation speed range expansion control to lower the induced voltage value Vi. The first phase angle is set as an advance angle of <NUM> degrees, for example. The second phase angle is set as a predetermined conduction phase of an advance angle of <NUM> degrees or more and <NUM> degrees or less, for example. Furthermore, the ECU <NUM> switches the first phase angle to the second phase angle when the rotation speed N has changed from less than the switching rotation speed Nt to not less than the switching rotation speed Nt.

The ECU <NUM> performs control of switching a state where three-phase alternating current power having a conduction period of <NUM> electrical degrees is supplied to the rotary electric machine <NUM> to a state where three-phase alternating current power having a conduction period of <NUM> electrical degrees is supplied to the rotary electric machine <NUM>, for example, in a state where the crankshaft <NUM> is rotated at the rotation speed within the cranking rotation speed range Rc. Furthermore, the ECU <NUM> switches the conduction period of <NUM> electrical degrees to the conduction period of <NUM> electrical degrees when the rotation speed N has changed from less than the switching rotation speed Nt to not less than the switching rotation speed Nt. That is, the ECU <NUM> changes the conduction period from <NUM> electrical degrees to <NUM> electrical degrees and changes the conduction phase from the first phase angle to the second phase angle when the rotation speed N has changed from less than the switching rotation speed Nt to not less than the switching rotation speed Nt.

After performing the assist control and the power running rotation speed range expansion control to start the engine <NUM>, the ECU <NUM> stops the power running rotation speed range expansion control and performs the power generation control in a state where the rotation speed N is larger than the cranking rotation speed range Rc. The power generation control is control of keeping the output voltage value Vb of the battery <NUM> constant by changing the conduction phase by the ECU <NUM>. The conduction period is <NUM> electrical degrees, for example.

When the output voltage value Vb of the battery <NUM> is less than the reference voltage value Vt, the ECU <NUM> does not perform the assist control and the power running rotation speed range expansion control and does not operate the switching elements <NUM> such that the rotation speed N is equal to or higher than the rotation speed N2 and the full-wave rectification state is established. Thus, alternating-current power from the rotary electric machine <NUM> is full-wave rectified by the body diodes included in the switching elements <NUM>, and direct-current power is supplied to the battery <NUM>, the ECU <NUM>, and the engine auxiliaries 1a.

When the battery <NUM> is not in the assistable charge state and the engine <NUM> is started, the crankshaft <NUM> is rotated at the rotation speed N equal to or higher than the rotation speed N2 such that the ECU <NUM> is activated with electric power regenerated from the rotary electric machine <NUM>.

In the outboard motor <NUM>, electric power is supplied from the rotary electric machine <NUM> to the fuel injector <NUM>, fuel is injected, electric power is supplied to the ignition device <NUM>, and the engine <NUM> is started.

A method for starting the engine <NUM> of the outboard motor <NUM> according to preferred embodiments is now described with reference to <FIG>, <FIG>, and <FIG>. <FIG> is a flowchart illustrating rotary electric machine control processing performed by the control circuit <NUM> of the outboard motor <NUM>. <FIG> is a flowchart illustrating engine control processing performed by the control circuit <NUM> of the outboard motor <NUM>. <FIG> shows waveforms in the outboard motor <NUM> when the battery <NUM> is in the assistable charge state and the assist control and the power running rotation speed range expansion control are performed.

First, as shown in <FIG>, the main switch <NUM> and the start switch <NUM> are turned on by the operator. Then, as shown in <FIG>, the puller <NUM> is pulled by the operator, and the rope <NUM> wound around the rope reel <NUM> is pulled out. Accordingly, the rope reel <NUM> is rotated. When the rope reel <NUM> is rotated, the FWM <NUM> and the crankshaft <NUM> are rotated via the cam plate <NUM> etc. When the FWM <NUM> rotates, a change in the rotation angle is acquired by the rotation angle sensor <NUM>, as shown in <FIG>. Furthermore, the rotation speed N is acquired based on the change in the rotation angle.

When the battery <NUM> is charged, a change in the rotation angle at the start of rotation of the rope reel <NUM> is acquired in a state where the ECU <NUM> is activated. On the other hand, when the battery <NUM> is not charged, the amount of battery <NUM> remaining is less than the amount of electric power enough to activate the ECU <NUM>, or the battery <NUM> is not connected to the ECU <NUM>, the ECU <NUM> stops. In this case, rotation of the rope reel <NUM> is started, the switching elements <NUM> do not operate, the ECU <NUM> is in the full-wave rectification state, and using electric power regenerated from the rotary electric machine <NUM>, direct-current power is supplied to the battery <NUM>, the ECU <NUM>, and the engine auxiliaries 1a. Then, when the ECU <NUM> is activated with the electric power from the rotary electric machine <NUM>, the following rotary electric machine control processing and engine control processing are executed.

As shown in <FIG>, in step S1, it is determined whether or not the amount of battery <NUM> remaining is enough to assist the operator to start the engine <NUM>. That is, it is determined whether or not the battery <NUM> is in the assistable charge state. When the amount of battery <NUM> remaining is enough to assist the operator to start the engine <NUM>, the processing advances to step S2, and when the amount of battery <NUM> remaining is not enough to assist the operator to start the engine <NUM>, the processing advances to step S9.

In step S2, it is determined whether or not the number of edge inputs from the rotation angle sensor <NUM> is one or more. This determination is repeated until the number of edge inputs from the rotation angle sensor <NUM> becomes one or more. When the number of edge inputs from the rotation angle sensor <NUM> is one or more, the processing advances to step S3.

In step S3, the assist control is started. Specifically, the switching elements <NUM> operate with the conduction period of <NUM> electrical degrees and the first phase angle, and electric power is supplied from the battery <NUM> to the rotary electric machine <NUM>. For example, as shown in <FIG>, a value of an output current Ib that flows from the battery <NUM> to the rotary electric machine <NUM> increases. Thereafter, the processing advances to step S4.

In step S4, it is determined whether or not the rotation speed N is equal to or higher than the switching rotation speed Nt. This determination is repeated until the rotation speed N becomes equal to or higher than the switching rotation speed Nt. When the rotation speed N is equal to or higher than the switching rotation speed Nt, the processing advances to step S5.

In step S5, the power running rotation speed range expansion control is started. For example, the conduction period is changed from <NUM> electrical degrees to <NUM> electrical degrees, and the conduction phase is advanced from the first phase angle (<NUM> degrees) to the second phase angle (advance angle <NUM> degrees or advance angle <NUM> degrees). Thereafter, the processing advances to step S6.

In step S6, it is determined whether or not the engine control mode is the "post-initial explosion completion mode". This determination is repeated until the engine control mode becomes the "post-initial explosion completion mode", and when the engine control mode is the "post-initial explosion completion mode", the processing advances to step S7.

In step S7, the power generation control is started. That is, the magnitude of regeneration power is controlled such that the conduction phase is changed, and the output voltage value Vb becomes a constant value. At this time, the conduction period is <NUM> electrical degrees. Thereafter, the processing advances to step S8.

In step S8, it is determined whether or not the engine control mode is the "engine stop mode". This determination is repeated until the engine control mode becomes the "engine stop mode", and when the engine control mode is the "engine stop mode", the processing returns to step S1.

In step S9, to which the processing advances when it is determined in step S1 that the amount of battery <NUM> remaining is not enough to assist the operator to start the engine <NUM>, it is determined whether or not the engine control mode is the "post-initial explosion completion mode". When the engine control mode is not the "post-initial explosion completion mode", the processing returns to step S1. When the engine control mode is the "post-initial explosion completion mode", the processing advances to step S7.

As shown in <FIG>, in step S21, the engine control mode is set to the "engine stop mode". Thereafter, the processing advances to step S22.

In step S22, it is determined whether or not a signal from the crank sensor 14a is at a low level and the number of edge inputs from the rotation angle sensor <NUM> is one or more. That is, it is determined whether or not a change in the rotation angle has been detected by the rotation angle sensor <NUM>. When the battery <NUM> is in the assistable charge state, a change in the rotation angle at the start of rotation of the rope reel <NUM> is acquired in a state where the ECU <NUM> is activated. On the other hand, when the battery <NUM> is uncharged, rotation of the rope reel <NUM> is started in a state where the ECU <NUM> stops, and a change in the rotation angle at the activation of the ECU <NUM> is acquired with electric power regenerated from the rotary electric machine <NUM>. When the number of edge inputs from the rotation angle sensor <NUM> is one or more, the processing advances to step S23. When the number of edge inputs from the rotation angle sensor <NUM> is not one or more, the processing returns to step S21.

In step S23, the first injection execution period is started. That is, when a change in the rotation angle is acquired from the rotation angle sensor <NUM> (when the number of edge inputs is one or more), the fuel injector <NUM> starts to be controlled to inject fuel asynchronously with the operation of the crankshaft <NUM>. Thereafter, the processing advances to step S24.

In step S24, it is determined whether or not the number of edge inputs from the crank sensor 14a is one or more. This determination is repeated until the number of edge inputs from the crank sensor 14a becomes one or more, and when the number of edge inputs from the crank sensor 14a is one or more, the processing advances to step S25.

In step S25, the ignition execution period is started. Thereafter, the processing advances to step S26.

In step S26, it is determined whether or not the rotation speed N is equal to or higher than the predetermined rotation speed Ni. This determination is repeated until the rotation speed N becomes equal to or higher than the predetermined rotation speed Ni, and when the rotation speed N is equal to or higher than the predetermined rotation speed Ni, the processing advances to step S27. That is, when initial explosion occurs in the engine <NUM>, the engine <NUM> is started, the rotation speed N is increased, and the processing advances to step S27.

In step S27, the engine control mode is set to the "post-initial explosion completion mode". Thereafter, the processing advances to step S28. In step S28, the second injection execution period is started. That is, the fuel injector <NUM> starts to be controlled to inject fuel synchronously with the operation of the crankshaft <NUM>. Thereafter, the processing advances to step S29.

In step S29, it is determined whether or not a state where there is no edge input from the rotation angle sensor <NUM> has continued for the predetermined time or more. This determination is repeated until a state where there is no edge input from the rotation angle sensor <NUM> has continued for the predetermined time or more. When a state where there is no edge input from the rotation angle sensor <NUM> has continued for the predetermined time or more, the processing returns to step S21.

Results of comparison between the outboard motor <NUM> according to preferred embodiments and an outboard motor according to a comparative example are now described with reference to <FIG> and <FIG>.

As shown in <FIG>, a load required to pull the rope <NUM> when the assist control and the power running rotation speed range expansion control are performed by the outboard motor <NUM> according to preferred embodiments and a load required to pull a rope in the outboard motor according to the comparative example that does not perform the assist control and the power running rotation speed range expansion control were measured. Specifically, the magnitude of a load corresponding to a crank angle (up to about <NUM> degrees) when the rope was pulled from a <NUM>-degree crank angle was measured.

As shown in <FIG>, the load of the outboard motor <NUM> according to preferred embodiments was smaller than the load of the outboard motor according to the comparative example at any point from a <NUM>-degree crank angle to an <NUM>-degree crank angle. From this result, it has been found that the load required when the operator pulls the rope <NUM> is decreased by performing the assist control and the power running rotation speed range expansion control.

As shown in <FIG>, a pressure P1 inside the cylinders <NUM> (in-cylinder pressure) when the engine <NUM> is started by pulling the rope <NUM> while performing the assist control and the power running rotation speed range expansion control in the outboard motor <NUM> according to preferred embodiments and a pressure P2 inside cylinders when an engine is manually started in the outboard motor according to the comparative example that does not perform the assist control and the power running rotation speed range expansion control were measured.

In the outboard motor according to the comparative example, the rope was pulled from a <NUM>-degree crank angle, and the pressure P2 inside the cylinders did not increase at the position of the first compression stroke (in the vicinity of a <NUM>-degree crank angle) or did not exceed an initial explosion possible pressure Pt. Therefore, in the outboard motor according to the comparative example, the engine was not started at the position of the first compression stroke. After that, in the second compression stroke, which was reached by continuously pulling the rope, the pressure P2 inside the cylinders increased and exceeded the initial explosion possible pressure Pt, and the engine started.

On the other hand, in the outboard motor <NUM> according to preferred embodiments, the rope <NUM> was pulled from a <NUM>-degree crank angle, the crankshaft <NUM> was rotated by the assist control and the power running rotation speed range expansion control, and at the position of the first compression stroke (in the vicinity of a <NUM>-degree crank angle), the pressure P1 inside the cylinders <NUM> exceeded the initial explosion possible pressure Pt, and initial explosion occurred. Thus, the engine <NUM> started. In addition, in the outboard motor <NUM> according to preferred embodiments, the crankshaft <NUM> was continuously rotated by the engine <NUM> and the rotary electric machine <NUM> even after the initial explosion, and even in second and subsequent compression strokes, the pressure P1 inside the cylinders <NUM> exceeded the initial explosion possible pressure Pt.

Therefore, it has been found that the initial explosion occurs in the first compression stroke in the outboard motor <NUM> according to preferred embodiments unlike the outboard motor according to the comparative example.

According to the various preferred embodiments described above, the following advantageous effects are achieved.

According to a preferred embodiment, the ECU <NUM> is configured or programmed to perform the assist control of assisting rotation of the crankshaft <NUM> by the rotary electric machine <NUM> in a state where the crankshaft <NUM> is rotated at the rotation speed N within the cranking rotation speed range Rc (hereinafter referred to as the "range Rc") due to rotation of the rope reel <NUM>. Accordingly, when the operator pulls the rope <NUM> to rotate the rope reel <NUM>, the rotary electric machine <NUM> assists in rotation of the crankshaft <NUM>, and thus a torque from the rotary electric machine <NUM> is applied to the crankshaft <NUM>, and a force (load) of pulling the rope <NUM> required to exceed a resistance on the compression stroke of the engine <NUM> is decreased. This advantageous effect is confirmed by the above comparison results. In addition, unlike the case where an accumulation power spring is provided, a preliminary operation of winding an accumulation power spring in advance is not necessary, and thus the work burden of starting the engine <NUM> on the operator is decreased.

According to a preferred embodiment, the rotary electric machine <NUM> assists in rotation of the crankshaft <NUM> such that even when the force of the operator to pull the rope <NUM> is relatively small, the rotation speed N of the crankshaft <NUM> is increased. Consequently, the pressure inside the cylinders <NUM> of the engine <NUM> is increased due to the increased rotation speed N of the crankshaft <NUM>, and thus the possibility that initial explosion occurs in the engine <NUM> is increased, and the engine <NUM> is more reliably started. (<NUM>) According to the invention, the ECU <NUM> is configured or programmed to perform the power running rotation speed range expansion control of expanding the power running rotation speed range Rd of the rotary electric machine <NUM> in a state where the crankshaft <NUM> is rotated at the rotation speed N within the range Rc. Accordingly, when the rotary electric machine <NUM> is designed such that the induced voltage value Vi of the rotary electric machine <NUM> exceeds the output voltage value Vb of the battery <NUM> within the range Rc, that is, even when the upper limit value N1b of the cranking rotation speed range Rc is larger than the upper limit value N2 of the power running rotation speed range Rd, the power running rotation speed range Rd is expanded by the power running rotation speed range expansion control such that the rotary electric machine <NUM> performs the power running operation. Consequently, when the power running rotation speed range expansion control is not performed (when the conduction regeneration control is performed or in the full-wave rectification state), electric power is returned from the rotary electric machine <NUM> to the battery <NUM> within the range Rc, and when the power running rotation speed range expansion control is performed, the induced voltage value Vi is lowered below the output voltage value Vb of the battery <NUM> within the range Rc, and the assist control is performed. Consequently, even when electric power is not supplied from the battery <NUM>, the operator pulls the rope <NUM> to rotate the rope reel <NUM> and rotate the crankshaft <NUM> at the rotation speed within the range Rc such that using the electric power returned from the rotary electric machine <NUM>, the fuel injector <NUM> and the ignition device <NUM> operate to start the engine <NUM>. Therefore, a state where the engine <NUM> is reliably and quickly started is maintained while the work burden of starting the engine <NUM> is decreased. That is, even in the case of the amount of battery <NUM> remaining not enough to assist the operator to start the engine <NUM>, the actuators related to fuel injection operate to start the engine <NUM>.

According to a preferred embodiment, the rotary electric machine <NUM> is constructed such that the power generation rotation speed range Rg, which is the range of the rotation speed N of the crankshaft <NUM> within which the induced voltage value Vi is not less than the output voltage value Vb of the battery <NUM>, overlaps with the range Rc in a state where the power running rotation speed range expansion control is not performed by the ECU <NUM>. Furthermore, the ECU <NUM> is configured or programmed to, in a state where the crankshaft <NUM> is rotated at the rotation speed N at least within the overlapping rotation speed range, perform the power running rotation speed range expansion control to lower the induced voltage value Vi below the output voltage value Vb and perform the assist control. Accordingly, when the crankshaft <NUM> is rotated at the rotation speed N within the overlapping rotation speed range, and the power running rotation speed range expansion control is not performed, electric power is returned from the rotary electric machine <NUM> to the battery <NUM>. When the crankshaft <NUM> is rotated at the rotation speed N within the overlapping rotation speed range, and the power running rotation speed range expansion control is performed, the assist control is easily performed.

According to a preferred embodiment, the ECU <NUM> is configured or programmed to perform the assist control and the power running rotation speed range expansion control when the battery <NUM> is in the assistable charge state. Accordingly, when the battery <NUM> is charged with electric power and the electric power of the battery <NUM> is usable, the power running rotation speed range Rd of the rotary electric machine <NUM> is expanded by the power running rotation speed range expansion control such that the rotary electric machine <NUM> assists in rotation of the crank shaft <NUM>.

According to a preferred embodiment, when the battery <NUM> is not in the assistable charge state, and the crank shaft <NUM> is rotated at the rotation speed N within the range Rc due to rotation of the rope reel <NUM>, electric power is regenerated from the rotary electric machine <NUM>. Accordingly, when the battery <NUM> is not charged with electric power, and the assist control is not possible, the rope reel <NUM> is rotated such that the crankshaft <NUM> is rotated at the rotation speed N within the range Rc so as to regenerate and supply electric power to operate the fuel injector <NUM> and the ignition device <NUM> and further to charge the battery <NUM>. That is, the rope reel <NUM> is rotated such that the fuel injector <NUM> etc. immediately operate with the regenerated electric power.

According to a preferred embodiment, the actuators related to FI is provided in the outboard motor <NUM>, and electric power from the rotary electric machine <NUM> is supplied to the actuators related to FI and the ECU <NUM> when the battery <NUM> is not in the assistable charge state, and the crankshaft <NUM> is rotated at the rotation speed N within the cranking rotation speed range Rc due to rotation of the rope reel <NUM>. Accordingly, even when the battery <NUM> is not in the assistable charge state, the actuators related to FI and the ECU <NUM> are driven with the electric power regenerated from the rotary electric machine <NUM> when the ECU <NUM> is in the full-wave rectification state, for example, to start the engine <NUM>.

According to a preferred embodiment, the ECU <NUM> is configured or programmed to be activated with electric power from the rotary electric machine <NUM> when the battery <NUM> is not in the assistable charge state, and the crankshaft <NUM> is rotated at the rotation speed N within the range Rc due to rotation of the rope reel <NUM>. Accordingly, even when the battery <NUM> is not in the assistable charge state, the rope reel <NUM> is rotated to activate the ECU <NUM>. Consequently, even when the battery <NUM> is not in the assistable charge state, the ECU <NUM> is activated to appropriately control the operation of the rotary electric machine <NUM>.

According to a preferred embodiment, the ECU <NUM> is configured or programmed to perform the assist control and the power running rotation speed range expansion control when the output voltage value Vb applied from the battery <NUM> is equal to or larger than the reference voltage value Vt as when the battery <NUM> is in the assistable charge state. Accordingly, the output voltage value Vb applied from the battery <NUM> is compared with the reference voltage value Vt such that it is easily determined whether or not the battery <NUM> is in the assistable charge state, and when the battery <NUM> is sufficiently charged with electric power, the assist control is performed.

According to a preferred embodiment, the ECU <NUM> is configured or programmed to start the power running rotation speed range expansion control upon change of the rotation speed N of the crankshaft <NUM> from less than the switching rotation speed Nt to not less than the switching rotation speed Nt within the range Rc when performing the assist control. Accordingly, when the rotation speed N of the crankshaft <NUM> is less than the switching rotation speed Nt, the rotary electric machine <NUM> is rotated to increase the torque without performing the power running rotation speed range expansion control, and when the rotation speed N is not less than the switching rotation speed Nt such that the torque is decreased due to the increased induced voltage value Vi, the rotary electric machine <NUM> is rotated to increase the torque with performing the power running rotation speed range expansion control. Consequently, even when the crankshaft <NUM> is rotated at any rotation speed N, the torque is increased, and thus the rotary electric machine <NUM> efficiently assists in rotation of the crankshaft <NUM>.

According to a preferred embodiment, the ECU <NUM> is configured or programmed to, when performing the assist control, perform the advance angle control on the rotary electric machine <NUM> in a state where the crankshaft <NUM> is rotated at the rotation speed within the range Rc so as to perform the power running rotation speed range expansion control to lower the induced voltage value Vi. Accordingly, the induced voltage value Vi of the rotary electric machine <NUM> is lowered in response to a change in the conduction phase of electric power to be supplied to the rotary electric machine <NUM>, and thus the power running rotation speed range expansion control is easily performed.

According to a preferred embodiment, the ECU <NUM> is configured or programmed to, when performing the assist control, perform control of switching the conduction phase to the rotary electric machine <NUM> from the first phase angle to the second phase angle larger than the first phase angle in a state where the crankshaft <NUM> is rotated at the rotation speed within the range Rc so as to perform the power running rotation speed range expansion control to lower the induced voltage value Vi. Accordingly, the conduction phase to the rotary electric machine <NUM> is switched such that the induced voltage value Vi is lowered. Therefore, the conduction phase to the rotary electric machine <NUM> is advanced (switched) from the first phase angle to the second phase angle such that the power running rotation speed range expansion control is easily performed.

According to a preferred embodiment, the rotary electric machine <NUM> rotates with three-phase alternating current power supplied to the rotary electric machine <NUM>. Furthermore, the ECU <NUM> is configured or programmed to perform the assist control while supplying the three-phase alternating current power having the conduction period of <NUM> electrical degrees larger than <NUM> electrical degrees to the rotary electric machine <NUM> in a state where the crankshaft <NUM> is rotated at the rotation speed N within the range Rc. Accordingly, the power running rotation speed range is further expanded.

According to a preferred embodiment, the ECU <NUM> is configured or programmed to perform the assist control while supplying the three-phase alternating current power having the conduction period of <NUM> electrical degrees to the rotary electric machine <NUM> in a state where the crankshaft <NUM> is rotated at the rotation speed N less than the switching rotation speed Nt within the range Rc, and is configured or programmed to perform the assist control while supplying the three-phase alternating current power having the conduction period of <NUM> electrical degrees to the rotary electric machine <NUM> in a state where the crankshaft <NUM> is rotated at the rotation speed not less than the switching rotation speed Nt within the range Rc. Accordingly, when the crankshaft <NUM> is rotated at the rotation speed N less than the switching rotation speed Nt at which the induced voltage value Vi is relatively small, the conduction period is set to <NUM> electrical degrees such that more efficient assist control is performed, and when the crankshaft <NUM> is rotated at the rotation speed N not less than the switching rotation speed Nt at which the induced voltage value Vi is relatively large, the conduction period is changed to the conduction period of <NUM> electrical degrees such that the power running rotation speed range Rd is expanded, and the assist control is performed while significantly reducing or preventing a decrease in torque.

According to a preferred embodiment, the ECU <NUM> is configured or programmed to, in a state where the crankshaft <NUM> is rotated at the rotation speed N larger than the range Rc, stop the power running rotation speed range expansion control and perform the power generation control. Accordingly, when the engine <NUM> is started and the crankshaft <NUM> is rotated at the rotation speed N larger than the range Rc, the output voltage value Vb of the battery <NUM> is constant, and thus electric power is appropriately supplied to the engine auxiliaries la including the fuel injector <NUM> and the ignition device <NUM> while the battery <NUM> is charged.

According to a preferred embodiment, the outboard motor <NUM> includes the rotation angle sensor <NUM> that acquires the rotation angle of the rotary electric machine <NUM>. Furthermore, the ECU <NUM> is configured or programmed to divert, to the power running rotation speed range expansion control and the assist control, the rotation angle necessary for the conduction control of the rotary electric machine <NUM> and detected by the rotation angle sensor <NUM>. Accordingly, it is not necessary for the operator to perform an input operation when the assist control is started, and thus an operation of starting the engine <NUM> becomes simpler.

According to a preferred embodiment, the ECU <NUM> is configured or programmed to, after the rotation speed N of the crankshaft <NUM> exceeds the rotation speed of the rope reel <NUM>, continue to perform the power running rotation speed range expansion control and perform control of supplying electric power from the battery <NUM> to the rotary electric machine <NUM> to rotate the crankshaft <NUM>. Accordingly, even when the operator cannot perform a cranking operation enough to start the engine <NUM>, the engine <NUM> is started while the crankshaft <NUM> is continuously rotated by the rotary electric machine <NUM>. Consequently, the length of the rope <NUM> is decreased.

According to a preferred embodiment, the engine <NUM> includes the fuel injector <NUM> and the ignition device <NUM>. Furthermore, the ECU <NUM> is configured or programmed to, at least until fuel injection by the fuel injector <NUM> is completed and initial ignition by the ignition device <NUM> is completed, continue to perform the power running rotation speed range expansion control and perform control of supplying electric power from the battery <NUM> to the rotary electric machine <NUM> in a state where the crankshaft <NUM> is rotated at the rotation speed N within the range Rc. Accordingly, the rotary electric machine <NUM> assists in rotation of the crankshaft <NUM> at least until ignition is performed in the engine <NUM>, and thus the engine <NUM> is more reliably started.

According to a preferred embodiment, the rotary electric machine <NUM> includes the FWM <NUM> directly connected to the crankshaft <NUM> and the stator <NUM> that faces the permanent magnets <NUM> in the radial direction of the crankshaft <NUM>. Accordingly, unlike the case where the rotary electric machine and the crankshaft are not directly connected to each other, as the case where a gear or the like is provided between the rotary electric machine and the crankshaft, complication of the configuration of the outboard motor <NUM> is significantly reduced or prevented. Furthermore, with the above configuration, an existing rotary electric machine <NUM> provided in a general outboard motor is usable as the rotary electric machine <NUM> that assists in rotation of the crankshaft <NUM>.

According to a preferred embodiment, the battery <NUM> that supplies electric power to the rotary electric machine <NUM> and to which electric power is returned from the rotary electric machine <NUM> is disposed in the outboard motor <NUM>. Accordingly, there is no need to provide a power line through which electric power is exchanged between the marine vessel and the outboard motor <NUM> unlike the case where electric power is supplied from the battery provided in the marine vessel (vessel body) to the rotary electric machine. Consequently, the configuration that connects the outboard motor <NUM> to the marine vessel is simplified.

The preferred embodiments described above are illustrative in all points and not restrictive.

For example, while the rotary electric machine <NUM> is preferably directly connected to the crankshaft <NUM> in preferred embodiments described above, the present teaching is not restricted to this. For example, a gear may alternatively be provided on a flywheel, and the rotary electric machine <NUM> may alternatively be connected to the crankshaft <NUM> via the gear.

While the ECU <NUM> is preferably configured or programmed to perform the power running rotation speed range expansion control when the rotation speed N of the crankshaft <NUM> is equal to or higher than the switching rotation speed Nt in preferred embodiments described above, the present teaching is not restricted to this. For example, the ECU <NUM> may alternatively be configured or programmed to perform the power running rotation speed range expansion control at the start of the assist control (when the rotation speed N is approximately zero).

While upon change of the rotation speed N from less than the switching rotation speed Nt to not less than the switching rotation speed Nt, the first phase angle is switched to the second phase angle, and the conduction period is switched from <NUM> electrical degrees to <NUM> electrical degrees in preferred embodiments described above, the present teaching is not restricted to this. For example, upon change of the rotation speed N from less than a first switching rotation speed Nt1 to not less than the first switching rotation speed Nt1, the first phase angle may alternatively be switched to the second phase angle, and upon change of the rotation speed N from less than a second switching rotation speed Nt2 different from the first switching rotation speed Nt1 to not less than the second switching rotation speed Nt2, the conduction period may alternatively be switched from <NUM> electrical degrees to <NUM> electrical degrees.

While the ECU <NUM> is preferably configured or programmed to start the assist control based on a change in the rotation angle of the rotation angle sensor <NUM> in preferred embodiments described above, the present teaching is not restricted to this. For example, a switch (lever) or the like that starts the assist control may alternatively be provided on the puller <NUM> of the outboard motor <NUM>, and the ECU <NUM> may alternatively be configured or programmed to start the assist control when the operator operates the switch (lever) or the like.

While the second phase angle in the power running rotation speed range expansion control is preferably set as an advance angle of <NUM> degrees or more and <NUM> degrees or less, and the conduction period in the power running rotation speed range expansion control is preferably set as the conduction period of <NUM> electrical degrees in preferred embodiments described above, the present teaching is not restricted to this. That is, the second phase angle may alternatively be set as an advance angle of less than <NUM> degrees or more than <NUM> degrees, and the conduction period in the power running rotation speed range expansion control may alternatively be set as a conduction period of more than <NUM> electrical degrees other than <NUM> electrical degrees.

While in the power running rotation speed range expansion control, the first phase angle is preferably switched to the second phase angle at once in preferred embodiments described above, the present teaching is not restricted to this. That is, in the power running rotation speed range expansion control, the conduction phase may alternatively be gradually advanced from the first phase angle to the second phase angle according to an increase in the rotation speed N.

While the battery <NUM> is preferably disposed in the outboard motor <NUM> in preferred embodiments described above, the present teaching is not restricted to this. That is, the battery may alternatively be disposed in the vessel body <NUM> (marine vessel).

While the main switch <NUM> is preferably provided in the outboard motor <NUM> in preferred embodiments described above, the present teaching is not restricted to this. For example, as in an outboard motor <NUM> according to a first modified preferred embodiment shown in <FIG>, a battery <NUM> and a power supply terminal 240a of an ECU <NUM> may be directly connected to each other by wiring. In this case, electric power is constantly supplied from the battery <NUM> to the power supply terminal 240a of the ECU <NUM>. Thus, in the outboard motor <NUM> according to the first modified preferred embodiment, a main switch <NUM> is not provided such that the configuration is simplified.

As in an outboard motor <NUM> according to a second modified preferred embodiment shown in <FIG>, a battery <NUM> and an ECU <NUM> may not be directly connected to each other unlike the outboard motor <NUM> according to the first modified preferred embodiment. In this case, electric power is supplied from the battery <NUM> to a power supply terminal 340a of the ECU <NUM> via a start switch <NUM> and a diode 62a. Thus, in the outboard motor <NUM> according to the second modified preferred embodiment, a main switch <NUM> is not provided such that the configuration is simplified. Furthermore, electric power is not constantly supplied, and thus the dark current of the battery <NUM> is significantly reduced or prevented, and an increase in the size of the battery <NUM> is significantly reduced or prevented.

While the ECU <NUM> preferably includes the control circuit <NUM> and the switching elements <NUM> in preferred embodiments described above, the present teaching is not restricted to this. For example, the control circuit <NUM> and the switching elements <NUM> may alternatively be disposed separately from the ECU <NUM> in the outboard motor <NUM>.

While the present teaching is preferably applied to the engine starter that starts the engine <NUM> of the outboard motor <NUM> in preferred embodiments described above, the present teaching is not restricted to this. The present teaching may alternatively be applied to an engine starter that starts an engine of a vehicle, a motorcycle, or a snowmobile, or an engine disposed in the marine vessel, for example.

While the manual starter <NUM> preferably includes the rope reel <NUM> around which the rope <NUM> is wound in preferred embodiments described above, the present teaching is not restricted to this. For example, the manual starter may alternatively include a kick lever connected to the crankshaft, and the manual starter may alternatively be configured as a kick starter.

Claim 1:
An outboard motor (<NUM>, <NUM>, <NUM>) comprising:
an engine (<NUM>) including a crankshaft (<NUM>) and configured to start when the crankshaft (<NUM>) is rotated at a cranking rotation speed or higher, the cranking rotation speed being the lower limit of the rotation speed of the crankshaft at which initial explosion of the engine is possible;
a rope reel (<NUM>) around which a rope (<NUM>) is wound and connected to the crankshaft (<NUM>);
a rotary electric machine (<NUM>) connected to the crankshaft (<NUM>); and
a rotary electric machine controller (<NUM>, <NUM>, <NUM>) configured or programmed to control the rotary electric machine (<NUM>); wherein
the rotary electric machine controller (<NUM>, <NUM>, <NUM>) is configured or programmed to, in a state where the crankshaft (<NUM>) is rotated at a rotation speed within a cranking rotation speed range (Rc) including the cranking rotation speed due to rotation of the rope reel (<NUM>), perform assist control of assisting rotation of the crankshaft (<NUM>) by the rotary electric machine (<NUM>), characterized in that
the rotary electric machine controller (<NUM>, <NUM>, <NUM>) is further configured or programmed to, in a state where the crankshaft (<NUM>) is rotated at a rotation speed within the cranking rotation speed range (Rc) including the cranking rotation speed due to rotation of the rope reel (<NUM>), perform power running rotation speed range expansion control of expanding a power running rotation speed range (Rd) of the rotary electric machine (<NUM>) which is a range of the rotation speed of the crankshaft (<NUM>) within which electric power is supplied from a battery (<NUM>) to the rotary electric machine (<NUM>) so that an upper limit value of the power running rotation speed range (Rd) is greater than the upper limit value (N1b) of the cranking rotation speed range (Rc).