Straddled vehicle

Abstract

The purpose of the present invention is to raise the degree of freedom of assist control while suppressing any decrease in the service life of a lead battery in a straddled vehicle. This straddled vehicle comprises a lead battery and a control device. The lead battery is a high-charge-acceptance lead battery that is provided with higher charge acceptance performance than a lead battery for a normal vehicle. When the control device has executed crankshaft rotation assist control, in which a fixed-field starter generator is powered by electric power discharged from the high-charge-acceptance lead battery, and power generation control, in which the high-charge-acceptance lead battery is charged by electric power generated by a permanent magnet that is caused to rotate by a crankshaft, each a plurality of times during a time period in which the crankshaft is rotating, the control device controls the power generation and the powering of the fixed-field starter generator so that the high-charge-acceptance lead battery will be used at a charge amount greater than 50%.

Description

Straddled Vehicle

[0001] The present invention relates to a saddle-ride type vehicle.

[0002] As an example of a saddle-ride type vehicle, for example, Patent Document 1 discloses a motorcycle. The motorcycle in Patent Document 1 includes a battery, a starter-generator, and a control device. The starter-generator is connected to the crankshaft of the engine and is used to start the engine. The starter-generator generates electricity when rotated by the crankshaft. The battery is a lead battery. The control device executes engine start control, assist control, and power generation control. The engine start control is control that starts the engine by powering the starter-generator with power discharged from the lead battery. The assist control is control that applies torque in a direction that increases the rotation of the crankshaft, which is being rotated by powering the starter-generator with power discharged from the lead battery. In the power generation control, the starter-generator receives torque from the crankshaft and generates power to charge the lead battery.

[0003] Patent No. 5857624

[0004] It is desirable for saddle-ride type vehicles to be able to increase the number of assists or the strength of the assist, or to increase both the number of assists and the strength of the assist, while suppressing a decrease in the life of the lead battery. In other words, it is desirable for saddle-ride type vehicles to be able to increase the degree of freedom in assist control while suppressing a decrease in the life of the lead battery.

[0005] An object of the present invention is to increase the degree of freedom in assist control while suppressing a decrease in the lifespan of a lead battery in a saddle-ride type vehicle.

[0006] The present inventors have considered a method for increasing the degree of freedom in assist control while suppressing the shortening of the life of the lead battery.

[0007] The inventors discovered that, when repeatedly performing assist and charging in a configuration such as that shown in Patent Document 1, increasing the number of assist cycles or the strength of the assist may shorten the battery's lifespan. The power output from a lead-acid battery is power charged into the lead-acid battery by previous power generation by a starter-generator. Saddle-type vehicles, which are smaller than automobiles, are equipped with magnetic starter-generators, which are smaller than, for example, alternators. A magnetic starter-generator is configured so that a rotor equipped with a permanent magnet rotates while the crankshaft rotates. Therefore, the faster the crankshaft rotates, the faster the permanent magnet rotates, allowing the magnetic starter-generator to generate more power. In contrast, lead-acid batteries typically used in saddle-type vehicles, i.e., standard vehicle lead-acid batteries, have a lower charge acceptance capacity compared to their power output capacity. Therefore, the power generated by a magnetic starter-generator may be excessive relative to the acceptance capacity of the standard vehicle lead-acid battery. The excess power generated by the magnetic starter-generator is not charged and is wasted as heat or the like. Therefore, if the number of assists or the strength of the assist is increased, the situation where the next assist is performed before the amount of power discharged by the assist is replenished by charging increases, and the charge level of the lead-acid battery for a standard vehicle continues to decrease. If a lead-acid battery for a standard vehicle is used with a low charge level, its lifespan is likely to be shortened.

[0008] The inventors considered adopting a high-charge-acceptance lead-acid battery, which is a lead-acid battery with a higher charge acceptance capacity than a standard lead-acid battery, to accept more power generated by a magnetic starter-generator. Examples of high-charge-acceptance lead-acid batteries include lead-acid batteries for charge-controlled vehicles and lead-acid batteries for idling-stop vehicles. (See, for example, the web pages "Charge-Controlled Vehicle Batteries" and "Idling-Stop Vehicle Batteries" at https: / / gyb.gs-yuasa.com / products / .) By charging the high-charge-acceptance lead-acid battery with the large amount of power generated by a magnetic starter-generator that rotates in response to the rotation of the crankshaft, the charging current of the high-charge-acceptance lead-acid battery after discharge during assist can be increased. In other words, the high-charge-acceptance lead-acid battery can be charged in a shorter time. For example, the charge of a high-charge-acceptance lead-acid battery discharged during assist can be more quickly restored. This allows for an increase in the number of assists or the strength of the assist. Therefore, it is possible to widen the settable range of the number of assists or the strength of the assist, or to widen the settable range of both the number of assists and the strength.

[0009] However, when the inventors conducted assist and charging tests simulating actual driving conditions using a combination of a magneto starter generator and a high-charge-acceptance lead-acid battery, they found that the lifespan of the high-charge-acceptance lead-acid battery was sometimes shortened. The inventors' investigations revealed that a high-charge-acceptance lead-acid battery may have a higher internal resistance than a standard lead-acid battery with the same capacity. Further investigations by the inventors revealed that a high-charge-acceptance lead-acid battery may have a higher internal resistance than a standard lead-acid battery with the same capacity and charge level as the high-charge-acceptance lead-acid battery when the charge level is 50% or less.

[0010] Therefore, the inventors have devised a method for controlling the power running and power generation of a magneto starter generator so that a high-charge-acceptance lead-acid battery is used at a charge level greater than 50%. This allows the current acceptance of the high-charge-acceptance lead-acid battery to be higher than that of a standard lead-acid battery for a vehicle with an equivalent capacity. This makes it possible to suppress a decrease in the lifespan of the high-charge-acceptance lead-acid battery.

[0011] In this way, the power generated by the magnetic starter generator is charged into the high charge acceptance lead battery, and the power generation and operation of the magnetic starter generator are controlled so that the high charge acceptance lead battery is used at a charge level greater than 50%, thereby increasing the freedom of assist control while suppressing a decrease in the lifespan of the high charge acceptance lead battery.

[0012] A saddle-type vehicle according to each aspect of the present invention based on the above findings has the following configuration.

[0013] (1) A control device comprising: a lead battery; a starter-generator that rotates the crankshaft of the engine to start the engine and generates electricity by being rotated by the crankshaft; and a control device that is provided in an electrical path electrically connecting the lead battery and the starter-generator, and that executes at least an engine start control that powers the starter-generator with power discharged from the lead battery to apply torque to the stationary crankshaft to start the engine, a crankshaft rotation assist control that powers the starter-generator with power discharged from the lead battery to apply torque in a direction to increase the rotation of the rotating crankshaft, and a power generation control that causes the starter-generator to receive torque from the crankshaft and generate power to charge the lead battery. The starter-generator is connected to the crankshaft at a fixed reduction ratio without a clutch, or is fixed to the crankshaft without a clutch, and is configured so that a rotor equipped with a permanent magnet rotates while the crankshaft is rotating, and is a fixed-field magnet starter-generator that is more likely to generate excessive electricity while the crankshaft is rotating compared to a variable-field magnet generator. a control unit for controlling the power supply to the fixed-field starter-generator by the power discharged from the high-charge-acceptance lead-acid battery and the power generation control for charging the high-charge-acceptance lead-acid battery by the power generated by the permanent magnet rotated by the crankshaft, the ...

[0014] The straddle-type vehicle (1) includes a lead-acid battery, a starter-generator, and a control device. The lead-acid battery is a high-charge-acceptance lead-acid battery. The high-charge-acceptance lead-acid battery has characteristics similar to those of lead-acid batteries for charge-controlled vehicles or lead-acid batteries for vehicles with an idle-stop system, so that it can accept power generated by a fixed-field starter-generator, which tends to generate excessive power while the crankshaft is rotating. The high-charge-acceptance lead-acid battery has a characteristic of higher charge acceptance than a lead-acid battery for a standard vehicle. The control device applies torque in a direction that increases the rotation of the rotating crankshaft by powering the starter-generator with power discharged from the high-charge-acceptance lead-acid battery through crankshaft rotation assist control. The control device also applies torque in a direction that increases the rotation of the rotating crankshaft through power generation control, in which the starter-generator receives torque from the crankshaft to generate power that charges the lead-acid battery. A control device provided in an electrical path electrically connecting the high-charge-acceptance lead-acid battery and the fixed-field starter-generator executes a crankshaft rotation assist control, which powers the fixed-field starter-generator with power discharged from the high-charge-acceptance lead-acid battery, and a power generation control, which charges the high-charge-acceptance lead-acid battery with power generated by a permanent magnet rotated by the crankshaft, multiple times. By charging the high-charge-acceptance lead-acid battery with the large amount of power generated by the fixed-field starter-generator, the charging current of the high-charge-acceptance lead-acid battery after discharge during the assist can be increased. In other words, the high-charge-acceptance lead-acid battery can be charged in a shorter time. For example, a high-charge-acceptance lead-acid battery discharged during the assist can be charged in a shorter time. This allows the number of assists or the strength of the assist to be increased. In addition, when the control device performs crankshaft rotation assist control, which powers the fixed-field starter-generator with power discharged from the high-charge-acceptance lead-acid battery, and power generation control, which charges the high-charge-acceptance lead-acid battery with power generated by the rotating permanent magnet, multiple times, it controls the power generation and power generation of the fixed-field starter-generator so that the high-charge-acceptance lead-acid battery is used at a charge level greater than 50%. According to the configuration (1), the current acceptance of the high-charge-acceptance lead-acid battery charged with power generated by the fixed-field starter-generator can be made higher than the current acceptance of a standard lead-acid battery for a vehicle having an equivalent capacity.Therefore, the number of assists or the strength of the assist can be increased while suppressing a decrease in the lifespan of the high charge acceptance lead battery. That is, the number of assists or the strength of the assist can be increased, or both the number of assists and the strength can be increased. Therefore, the degree of freedom in controlling the assist can be increased while suppressing a decrease in the lifespan of the high charge acceptance lead battery.

[0015] (2) The saddle-ride type vehicle of (1), wherein the high charge acceptance characteristic lead battery has specific charge and discharge characteristics, and the specific charge and discharge characteristics are such that the accumulated charge energy is greater than 200 As × the rated capacity / 5 Ah when the high charge acceptance characteristic lead battery is discharged from a fully charged state at a 10-hour rate current with power equal to the rated capacity of the high charge acceptance characteristic lead battery, and then charged at a 10-hour rate current with power equal to 70% of the rated capacity × 5 Ah of the rated capacity, and then left for a further 20 hours, and then charged at a 1 / 3-hour rate current for 60 seconds under conditions of 25°C, and the control device controls the power running and power generation of the fixed field starter generator so that the high charge acceptance characteristic lead battery having the specific charge and discharge characteristics is used with a charge amount greater than 50% when the crankshaft rotation assist control and the power generation control are each performed multiple times.

[0016] According to the configuration (2), for example, the characteristics of the integrated charge energy obtained by the specific measurement method can be used as an index to easily select a high-charge-acceptance lead-acid battery that can increase the number of assists or the strength of the assist, or both the number of assists and the strength of the assist. Furthermore, by controlling the power running and power generation of the fixed-field starter-generator so that the high-charge-acceptance lead-acid battery selected based on this measurement method is used at a charge level greater than 50%, it is possible to increase the degree of freedom in assist control while suppressing a decrease in the life of the high-charge-acceptance lead-acid battery.

[0017] (3) A saddle-type vehicle according to (1) or (2), wherein the fixed-field starter-generator comprises a stator core having a plurality of teeth in which a plurality of slots are formed at intervals around the circumferential direction of the fixed-field starter-generator, and a stator having windings arranged to pass through the slots, and the rotor comprises a plurality of magnetic pole portions made up of the permanent magnets, and the number of the magnetic pole portions is greater than the number of the teeth.

[0018] According to the configuration (3), the angular velocity relative to the rotor rotation speed is higher than when the number of magnetic pole portions is smaller than the number of teeth. The angular velocity is the angular velocity in terms of the electrical angle based on the repetition period of the magnetic poles. When the angular velocity is high, the impedance of the winding is high. Furthermore, the angular velocity increases further as the rotor rotation speed increases. The impedance of the winding impedes the current flowing through the winding. Therefore, while the induced voltage increases as the rotor rotation speed increases, the large impedance of the winding suppresses excessive current output from the fixed-field starter-generator. Therefore, according to the saddle-type vehicle with the configuration (3), a lead battery with high charge acceptance can be charged with high efficiency even at a higher crankshaft rotation speed than when the number of magnetic pole portions is smaller than the number of teeth.

[0019] (4) A saddle-type vehicle according to any one of (1) to (3), wherein the control device executes control so that the ratio of a period during which the control for powering the starter-generator with power discharged from the lead battery to a period during which the starter-generator receives torque from the crankshaft and executes control to generate power for charging the lead battery exceeds a lower limit value set so as to make the charge amount of the high charge acceptance characteristic lead battery greater than 50%.

[0020] The configuration (4) can prevent the charge level of the high charge acceptance lead battery from dropping below 50%, and therefore the high charge acceptance lead battery can be charged efficiently even at a higher crankshaft rotation speed.

[0021] (5) In the saddle-type vehicle according to any one of (1) to (4), the control device prohibits the execution of the crankshaft rotation assist control when the charge amount of the high charge acceptance characteristic lead battery is smaller than an assist lower limit value set as a value greater than 50%.

[0022] According to the configuration of (5), it is possible to prevent the charge amount of the high charge acceptance lead battery from decreasing to 50% or less due to the crankshaft rotation assist control, and therefore the high charge acceptance lead battery can be charged with high efficiency even at a higher crankshaft rotation speed.

[0023] (6) A saddle-type vehicle according to any one of (1) to (5), wherein the control device executes idling stop control to stop the combustion operation of the engine when a predetermined idling stop condition is met, and prohibits the execution of the idling stop control when the charge amount of the high charge acceptance characteristic lead battery is less than an assist lower limit value set to a value greater than 50%.

[0024] According to the configuration of (6), it is possible to prevent the charge amount of the high charge acceptance lead battery from decreasing to 50% or less due to the engine start control after the idling stop control. Therefore, it is possible to charge the high charge acceptance lead battery with high efficiency even at a higher crankshaft rotation speed. Therefore, it is possible to charge the high charge acceptance lead battery with high efficiency even at a higher crankshaft rotation speed.

[0025] The terminology used herein is for the purpose of defining particular implementations only and is not intended to limit the invention. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed components. As used herein, the use of the terms "including," "comprising," or "having," and variations thereof, identifies the presence of stated features, steps, operations, elements, components, and / or equivalents thereof, but may include one or more of the steps, operations, elements, components, and / or groups thereof. As used herein, the terms "attached," "connected," "coupled," and / or equivalents thereof are used broadly and encompass both direct and indirect attachments, connections, and couplings. Furthermore, "connected" and "coupled" are not limited to physical or mechanical connections or couplings, but can include direct or indirect electrical connections or couplings. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms, such as those defined in commonly used dictionaries, should be interpreted to have a meaning consistent with the relevant technology and the meaning in the context of this disclosure, and should not be interpreted in an idealized or overly formal sense unless explicitly defined herein. It is understood that numerous techniques and processes are disclosed in the description of the present invention. Each of these has distinct advantages, and each can be used with one or more, or in some cases all, of the other disclosed technologies. Therefore, for the sake of clarity, this description will refrain from unnecessarily repeating all possible combinations of individual steps. Nevertheless, the specification and claims should be read with the understanding that all such combinations are within the scope of the present invention and claims. A novel straddle-type vehicle is described herein. In the following description, for purposes of explanation, numerous specific details are set forth to provide a thorough understanding of the present invention.However, it will be apparent to one skilled in the art that the present invention may be practiced without these specific details. The present disclosure is to be considered as an example of the present invention and is not intended to limit the present invention to the specific implementations illustrated in the following drawings or description.

[0026] A straddle-type vehicle is a vehicle in which a rider sits astride a saddle. Examples of straddle-type vehicles include scooter-type, moped-type, off-road, and on-road motorcycles. Furthermore, straddle-type vehicles are not limited to motorcycles, but may also include, for example, motor tricycles and ATVs (All-Terrain Vehicles). Motor tricycles may have two front wheels and one rear wheel, or one front wheel and two rear wheels. Furthermore, it is preferable that the vehicle be configured to be able to turn in a lean position. A vehicle configured to be able to turn in a lean position is configured to turn in a position tilted toward the center of a curve. As a result, a vehicle configured to be able to turn in a lean position resists the centrifugal force acting on the vehicle when turning. Examples of vehicles that are configured to be able to turn in a lean position include saddle-type vehicles (e.g., motorcycles and tricycles) that are configured to be able to turn in a lean position. Vehicles that are configured to be able to turn in a lean position require agility, so miniaturization is particularly important.

[0027] The engine is an internal combustion engine. The engine outputs energy from combustion as rotation of a crankshaft. The engine includes, for example, a four-stroke engine, a two-stroke engine, and a rotary engine. The engine is, for example, a single-cylinder engine having one cylinder. The engine is not particularly limited, and may be an engine having multiple cylinders.

[0028] A starter-generator is a rotating electric machine that functions as both a starting motor and a generator. The starter-generator in the present disclosure has an assist function of applying torque in a direction that increases the rotation of a rotating crankshaft. The starter-generator in the present disclosure is a fixed-field starter-generator. The starter-generator has, for example, more magnetic pole portions than the number of teeth. However, the starter-generator is not particularly limited, and may have magnetic pole portions equal to or less than the number of teeth.

[0029] A fixed-field starter-generator is a starter-generator with a fixed field strength. For example, a fixed-field starter-generator is a magnet-type starter-generator with a rotor equipped with permanent magnets. In contrast, a variable-field generator is a generator in which the field strength is variable under external control. For example, a variable-field generator is an alternator with a field winding whose strength varies depending on the current in the field winding. A variable-field generator can suppress its output power by controlling the current in the field winding, even when the crankshaft rotates at high speed. In contrast, the field strength of a fixed-field starter-generator is fixed. Simply put, the higher the rotational speed during power generation, the higher the power output of a fixed-field starter-generator. Therefore, the amount of power generated by a fixed-field starter-generator is more likely to be excessive while the crankshaft is rotating than that of a variable-field generator. The fact that the amount of power generated by a fixed-field starter-generator is excessive compared to that of a variable-field generator means, for example, that the amount of power generated by the fixed-field starter-generator is greater than that of a variable-field generator. When the power generation capacity of a fixed field starter generator is excessive compared to a variable field generator, it means, for example, that the power generation capacity is greater than that of a variable field generator and greater than the charge acceptance capacity of a high charge acceptance lead battery.

[0030] The control device executes at least engine start control, crankshaft rotation assist control, and power generation control. For example, the control device may execute controls other than engine start control, crankshaft rotation assist control, and power generation control. The control device has, for example, a processor that executes a program. The control device is not particularly limited, and may be configured, for example, as an electronic circuit without a processor.

[0031] In crankshaft rotation assist control, the control device powers the starter generator with power discharged from the lead battery while the crankshaft is rotating, applying torque in a direction that increases the rotation of the rotating crankshaft. Applying torque to a stationary crankshaft is not crankshaft rotation assist control, but starting control. As a result of crankshaft rotation assist control, for example, the rotation speed of the crankshaft increases.

[0032] A high charge acceptance lead battery is a lead battery with characteristics similar to those of a lead battery for a charge-controlled vehicle or a lead battery for an idle-stop vehicle. However, the high charge acceptance lead battery is not particularly limited, and may be any lead battery with higher charge acceptance characteristics than a lead battery for a standard vehicle. A high charge acceptance lead battery, for example, has the following specifications: When a high charge acceptance lead battery is fully charged, discharged at a 10-hour rate current with a power equal to the rated capacity, then further charged at a 10-hour rate current with a power equal to 70% of the rated capacity × rated capacity / 5 Ah, and then left for 20 hours, the accumulated charge energy is greater than 200 As × rated capacity / 5 Ah at 25°C for 60 seconds. However, the specifications of a high charge acceptance lead battery are not particularly limited, and may have specifications outside the above numerical range as long as it has higher charge acceptance characteristics than a standard vehicle lead battery.

[0033] The lead-acid battery for a normal vehicle is, for example, a starter battery. The lead-acid battery for a normal vehicle has a lower charge acceptance capacity than the lead-acid battery for a charge-controlled vehicle. The lead-acid battery for a normal vehicle also has a lower charge acceptance capacity than the lead-acid battery for an idle-stop vehicle.

[0034] The charge amount is the ratio of the battery's power to its rated capacity. The charge amount is usually expressed as a percentage. The charge amount is also sometimes referred to as the state of charge (SOC). Using a high charge acceptance lead battery at a charge amount greater than 50% means that the high charge acceptance lead battery is charged at a charge amount greater than 50% both during charging and discharging. Using a high charge acceptance lead battery at a charge amount greater than 50% means, for example, that the high charge acceptance lead battery is used so that the charge amount does not fall below 50% both during charging and discharging. In other words, using a high charge acceptance lead battery at a charge amount greater than 50% means, for example, that the high charge acceptance lead battery is used so that the charge amount does not fall below 50% both during charging and discharging.

[0035] The case where the number of magnetic pole portions of a fixed-field starter-generator is greater than the number of teeth includes, for example, a case where the number of magnetic pole portions is 4 / 3 of the number of teeth. However, the present invention is not particularly limited, and for example, the number of magnetic pole portions may be greater than the number of teeth but less than 4 / 3 of the number of teeth. Also, for example, the number of magnetic pole portions may be greater than 4 / 3 of the number of teeth. Also, the present invention is not particularly limited, and for example, the number of magnetic pole portions may be equal to or less than the number of teeth.

[0036] According to the present invention, it is possible to increase the degree of freedom in assist control while suppressing a decrease in the lifespan of a lead battery in a saddle-ride type vehicle.

[0037] FIG. 1 is a diagram schematically showing a saddle-ride type vehicle according to a first embodiment of the present invention. FIG. 2 is a graph showing an example of the charge amount-internal resistance characteristic of a lead battery with high charge acceptance. FIG. 3 is a cross-sectional view showing a fixed-field starter-generator according to a third embodiment. FIG. 4 is a flowchart illustrating the operation of a control device according to a fourth embodiment. FIG. 5 is a flowchart illustrating the operation of a control device according to a fifth embodiment. FIG. 6 is a flowchart illustrating the operation of a control device according to a sixth embodiment.

[0038] Hereinafter, the present invention will be described based on an embodiment with reference to the drawings.

[0039] [First embodiment] Fig. 1 is a diagram schematically showing a saddle-ride type vehicle according to a first embodiment of the present invention. Part (a) of Fig. 1 is a side view showing a schematic configuration of the saddle-ride type vehicle. Part (b) of Fig. 1 is a chart illustrating an example of transition of the charge amount.

[0040] The saddle-riding vehicle 1 shown in Fig. 1 includes a lead battery 30, a starter-generator 20, and a control device 60. More specifically, the saddle-riding vehicle 1 includes an engine 10. The engine 10 includes a crankshaft 15. The saddle-riding vehicle 1 also includes wheels 3a, 3b. The saddle-riding vehicle 1 includes the wheel 3b as a drive wheel. The engine 10 outputs power from the crankshaft 15 by performing a combustion operation. The power output from the crankshaft 15 is transmitted to the wheel 3b as a drive wheel.

[0041] The starter-generator 20 rotates the crankshaft 15 of the engine 10 to start the engine 10. The starter-generator 20 generates electricity when rotated by the crankshaft 15.

[0042] The starter-generator 20 is connected to the crankshaft 15 at a fixed reduction ratio without a clutch, or is fixed to the crankshaft 15 without a clutch. The starter-generator 20 always rotates in conjunction with the rotation of the crankshaft 15. When the starter-generator 20 is connected to the crankshaft 15 at a fixed reduction ratio without a clutch, for example, the starter-generator 20 is connected to the crankshaft 15 via a reduction gear or a reduction belt without a clutch. In this case, the starter-generator 20 is connected to rotate at a fixed reduction ratio relative to the crankshaft 15. When the starter-generator 20 is fixed to the crankshaft 15 without a clutch, for example, the starter-generator 20 is fixed to the end of the crankshaft 15. In this case, the reduction ratio is 1. In other words, the starter-generator 20 is connected to rotate at the same speed as the crankshaft 15.

[0043] The starter-generator 20 is a fixed-field starter-generator 20. Hereinafter, the starter-generator 20 according to each embodiment will also be referred to as a fixed-field starter-generator 20. The fixed-field starter-generator 20 is configured such that a rotor 70 equipped with a permanent magnet 77 rotates while the crankshaft 15 rotates. The fixed-field starter-generator 20 differs from, for example, a variable-field generator, which has a field winding and can change the magnitude of the field by adjusting the current flowing through the field winding. An example of a variable-field generator is an alternator. The fixed-field starter-generator 20 does not have a field winding, allowing for miniaturization. Unlike, for example, a variable-field generator, which has a field winding, the magnitude of the magnetic field generated by the permanent magnet 77 of the fixed-field starter-generator 20 is fixed. The fixed-field starter-generator 20 cannot reduce the magnitude of the magnetic field. In other words, even when the fixed-field starter-generator 20 rotates at high speed, the magnitude of the magnetic field cannot be reduced. Therefore, the fixed field starter-generator 20 is more likely to generate excessive power while the crankshaft 15 is rotating than a variable field generator.

[0044] The lead battery 30 is a high charge acceptance lead battery. Hereinafter, the lead battery 30 according to each embodiment will also be referred to as a high charge acceptance lead battery 30. The high charge acceptance lead battery 30 has a higher charge acceptance characteristic than a lead battery for a normal vehicle. The high charge acceptance lead battery 30 has characteristics similar to a lead battery for a charge-controlled vehicle or a lead battery for an idling-stop vehicle. The high charge acceptance lead battery 30 has a higher charge acceptance characteristic than a lead battery for a normal vehicle, such as a lead battery for a charge-controlled vehicle or a lead battery for an idling-stop vehicle. This allows the high charge acceptance lead battery 30 to accept power generated by a fixed-field starter-generator 20, which tends to generate excessive power while the crankshaft 15 is rotating. The lead battery for a charge-controlled vehicle is a lead battery designed to be charged with generated power controlled by varying the field of a variable-field generator.

[0045] The high charge acceptance lead battery 30 is configured to have a lower internal resistance than a standard automotive lead battery, at least when fully charged. The high charge acceptance lead battery 30 has improved charge acceptance, for example, by using a material containing carbon black as the negative electrode active material of the negative electrode plate. The inclusion of carbon black in the negative electrode active material can prevent lead sulfate from accumulating in the negative electrode active material. Lead sulfate is not easily reduced. The high charge acceptance lead battery 30 has high charge acceptance because lead sulfate, which is not easily reduced, is prevented from accumulating in the negative electrode active material. Furthermore, even when the high charge acceptance lead battery 30 is charged with a large current, lead sulfate is prevented from accumulating in the negative electrode active material. Therefore, the high charge acceptance lead battery 30 can be charged with a large current while preventing a decrease in its lifespan.

[0046] FIG. 2 is a graph showing an example of the charge capacity vs. internal resistance characteristic of a high charge acceptance lead battery. The solid line in FIG. 2 indicates the internal resistance G of an example high charge acceptance lead battery 30. The dashed line indicates the internal resistance Y of a standard vehicle lead battery having a capacity equivalent to that of the high charge acceptance lead battery 30 as a comparative example. The internal resistance is calculated from measurements of current per hour. The lower the internal resistance, the higher the charge acceptance performance. As shown in the graph in FIG. 2, the internal resistance G of the high charge acceptance lead battery 30 is smaller than the internal resistance Y of the standard vehicle lead battery in the region where the charge level exceeds 50%. In other words, in the region where the charge level exceeds 50%, the high charge acceptance lead battery 30 has a higher charge acceptance performance than the standard vehicle lead battery. However, in the region where the charge level is 50% or less, the internal resistance G of the high charge acceptance lead battery 30 is larger than the internal resistance Y of the standard vehicle lead battery. This is thought to be because the structure of the high charge acceptance lead battery 30 maintains a capacity equivalent to that of a lead battery for a normal vehicle while distributing the acceptance performance in a specific range.

[0047] The control device 60 shown in FIG. 1 is provided in the electrical path 4 electrically connecting the high charge acceptance characteristic lead battery 30 and the fixed-field type starter-generator 20. The control device 60 executes at least engine start control, power generation control, crankshaft rotation assist control, and power generation control. The control device 60 includes, for example, a processor that executes programs and a storage device that stores programs and data. By executing the programs, the control device 60 executes engine start control, power generation control, crankshaft rotation assist control, and power generation control. The engine start control is control for starting the engine 10. In the engine start control, the control device 60 powers the fixed-field type starter-generator 20 with power discharged from the high charge acceptance characteristic lead battery 30 to apply torque to the stationary crankshaft 15. This starts the engine 10.

[0048] The crankshaft rotation assist control is a control that powers the fixed-field starter-generator 20 with power discharged from the high charge acceptance lead battery 30 to apply torque in the rotational direction of the rotating crankshaft 15. This makes it possible to increase the rotational speed of the crankshaft 15 and suppress the degree to which the rotational speed of the crankshaft 15 decreases while traveling uphill. The power generation control is a control that causes the fixed-field starter-generator 20, which receives torque from the crankshaft 15, to generate power. The high charge acceptance lead battery 30 is charged with the power generated by the fixed-field starter-generator 20.

[0049] When the crankshaft rotation assist control and the power generation control are each executed multiple times while the crankshaft 15 is rotating, the control device 60 controls the power generation and power running of the fixed-field starter-generator 20. The control device 60 controls the power generation and power running of the fixed-field starter-generator 20 so that the high charge acceptance lead battery 30 is used with a charge amount greater than 50% during the above-mentioned period.

[0050] As a control method, for example, a method of controlling the periods of each control so that the ratio of the period during which the high charge acceptance lead battery 30 is charged to the period during which the fixed field starter-generator 20 is powered exceeds a lower limit value. As a control method, for example, a method of directly or indirectly obtaining the charge amount of the high charge acceptance lead battery 30 and prohibiting powering by the fixed field starter-generator 20 when the charge amount is smaller than a lower limit value can be used. As a control method, for example, both a method of controlling the ratio of the control periods and a method of prohibiting powering in accordance with the charge amount can be used.

[0051] The charge level of the high charge acceptance lead battery 30 is greater than 50%. Therefore, the current acceptance of the high charge acceptance lead battery 30, which is charged with the power generated by the fixed-field starter-generator 20, can be made higher than that of a lead battery for a standard vehicle having the same capacity. Therefore, the high charge acceptance lead battery 30, after being discharged by the assist, can be charged with a higher power than a lead battery for a standard vehicle while suppressing a decrease in its lifespan.

[0052] 1B, the solid line E indicates an example of the change in the charge amount of the high charge acceptance lead battery 30 of this embodiment. The dashed line P indicates an example of the change in the charge amount of a standard lead battery for a vehicle as a comparative example.

[0053] In the example graph of part (b) of Figure 1, engine start control is executed at time 0. The charge amount decreases due to the engine start control. Thereafter, while the crankshaft 15 is rotating, crankshaft rotation assist control is executed for periods A1, A2, etc. The charge amount also decreases due to the crankshaft rotation assist control. There is essentially no difference in the amount of charge decrease during crankshaft rotation assist control between the high charge acceptance lead battery 30 and a standard vehicle lead battery. During periods other than the crankshaft rotation assist control, the charge amount increases due to the charge control. The high charge acceptance lead battery 30 of this embodiment has a higher current acceptance than a standard vehicle lead battery, and therefore the increase in charge amount during the charge control period is greater.

[0054] In other words, the increase in charge amount during the period of charge control of the lead-acid battery for a standard vehicle is small. The power that is not charged is discarded. Therefore, if the crankshaft rotation assist control and the charge control are executed multiple times, the charge amount of the lead-acid battery for a standard vehicle may decrease excessively. If the charge amount decreases excessively, the life of the lead-acid battery for a standard vehicle will be shortened. In order to prevent the charge amount of the lead-acid battery for a standard vehicle from decreasing excessively, for example, a method of shortening the period during which the crankshaft rotation assist control is executed can be adopted. The dashed line Q shows the change in the charge amount of the lead-acid battery for a standard vehicle when the period during which the crankshaft rotation assist control is executed is shortened. In order to prevent an excessive decrease in the charge amount, the period of the crankshaft rotation assist control needs to be shortened to a1, a2, etc.

[0055] In contrast, the high-charge-acceptance lead-acid battery 30, which has a high current acceptance capability, can accept a larger current from the fixed-field starter-generator 20 than a standard lead-acid battery, which is prone to excessive current. In other words, the high-charge-acceptance lead-acid battery 30 is charged efficiently by utilizing the large amount of power generated by the fixed-field starter-generator 20. For example, the solid line E in the graph in part (b) of FIG. 1 shows a steep increase in the gradient during the power generation control period. As a result, the high-charge-acceptance lead-acid battery 30 is charged in a shorter time. Therefore, the lifespan of the high-charge-acceptance lead-acid battery 30 can be suppressed while increasing the assist time, the number of assists, or the strength of the assist compared to a standard lead-acid battery. In other words, the number of assists or the strength of the assist can be increased, or both the number and the strength can be increased. This means that the design of the saddle-ride type vehicle 1 can be configured to increase or decrease the number of assists or the strength of the assist, depending on, for example, the vehicle specifications. Therefore, with the straddle-type vehicle 1, it is possible to increase the degree of freedom in controlling the assist while suppressing a decrease in the life of the high charge acceptance characteristic lead battery 30.

[0056] [Second embodiment] The high charge acceptance lead battery 30 according to this embodiment has specific charge / discharge characteristics, which are characteristics in which the accumulated charge energy exceeds a standard when the battery is discharged from a fully charged state, charged to a reference power value, and then rapidly charged for a rapid charge test time.

[0057] More specifically, the high charge acceptance lead battery 30 has specific charge and discharge characteristics that can be obtained, for example, by the following procedure: First, discharge power equal to the rated capacity of the high charge acceptance lead battery 30 at a 10-hour rate current from a fully charged high charge acceptance lead battery 30. Then, charge power equal to 70% of the rated capacity x rated capacity / 5 Ah at a further 10-hour rate current. Then, leave the battery for another 20 hours. Then, perform a quick charge for 60 seconds at a 1 / 3-hour rate current under conditions of 25°C, and the accumulated charge energy is greater than 200 As x rated capacity / 5 Ah.

[0058] According to the configuration of this embodiment, for example, the characteristics of the integrated charge energy obtained by the specific measurement method described above can be used as an index to easily select a high charge acceptance lead battery 30. Furthermore, by controlling the high charge acceptance lead battery 30 selected based on this measurement method to be used at a charge level greater than 50%, it is possible to increase the degree of freedom in assist control while suppressing a decrease in the lifespan of the high charge acceptance lead battery 30.

[0059] Elements in this embodiment other than those described above are common to the first embodiment, so the same reference numerals will be used for the elements common to the first embodiment, and descriptions thereof will be omitted.

[0060] Third Embodiment FIG. 3 is a cross-sectional view showing a fixed-field starter-generator according to a third embodiment.

[0061] 3 includes a rotor 70 and a stator 80. The rotor 70 always rotates in conjunction with the rotation of the crankshaft 15.

[0062] The rotor 70 has a plurality of magnetic pole portions 77a. The plurality of magnetic pole portions 77a are formed by permanent magnets 77. The plurality of magnetic pole portions 77a are provided on the inner circumferential surface of the back yoke portion 74. The permanent magnet 77 has a plurality of permanent magnets 77. However, the plurality of magnetic pole portions 77a may also be formed as a single annular permanent magnet. The plurality of magnetic pole portions 77a are provided so that north poles and south poles are alternately arranged in the circumferential direction of the fixed-field starter-generator 20. In the example shown in FIG. 3 , the number of magnetic pole portions 77a of the rotor 70 facing the stator 80 is 24. The number of magnetic poles of the rotor 70 refers to the number of magnetic poles facing the stator 80. No magnetic material is provided between the magnetic pole portions 77a and the stator 80. The plurality of magnetic pole portions 77a are provided radially outward of the stator 80 in the fixed-field starter-generator 20.

[0063] The stator 80 has a stator core ST and a plurality of windings W. The stator core ST has a plurality of teeth (tooth portions) 85 spaced apart in the circumferential direction. The plurality of teeth 85 extend integrally radially outward from the stator core ST. In the example shown in FIG. 3 , a total of 18 teeth 85 are spaced apart in the circumferential direction. In other words, the stator core ST has a total of 18 slots SL spaced apart in the circumferential direction. A winding W is wound around each tooth 85. In other words, the windings W of multiple phases are arranged to pass through the slots SL.

[0064] The rotor 70 has magnetic pole portions 77a whose number is greater than the number of teeth 85. In the example shown in FIG.

[0065] The electrical angular velocity relative to the rotational speed of the rotor 70 in the fixed-field starter-generator 20 is greater than the electrical angular velocity when, for example, the number of magnetic pole portions 77a is less than the number of teeth. The electrical angular velocity is the electrical speed relative to the electrical angle based on the period of repetition of the magnetic poles, i.e., N poles and S poles, associated with the rotational speed of the rotor 70. When the electrical angular velocity is large, the electrical impedance of the winding W is large. If the electrical resistance of the winding W is R, the inductance of the winding W is L, and the rotational speed of the rotor 70 is ω, the impedance of the winding W is given by: ((ωL)２ +R ２ ) １／２ This is because the electrical angular velocity is correlated with the rotational speed of the rotor 70. The impedance of the winding W further increases as the rotational speed of the rotor 70 increases. Therefore, when the induced voltage increases as the rotational speed of the rotor 70 increases, the excessive current output from the fixed-field starter-generator 20 is suppressed. Therefore, the fixed-field starter-generator 20 can charge the high charge acceptance lead battery 30 with high efficiency even when the rotational speed of the crankshaft 15 is higher than when, for example, the number of magnetic pole portions is less than the number of teeth.

[0066] Elements in this embodiment other than those described above are common to the first embodiment, so the same reference numerals will be used for the elements common to the first embodiment, and descriptions thereof will be omitted.

[0067] Fourth Embodiment FIG. 4 is a flowchart illustrating the operation of a control device according to a fourth embodiment.

[0068] If the crankshaft 15 is not rotating (No in S11) and the engine 10 start conditions are met (Yes in S12), the control device 60 executes engine start control (S13). To determine whether the crankshaft 15 is rotating, the control device 60 uses, for example, an output signal from a rotation sensor (not shown) that detects the rotation of the crankshaft 15 or the rotor 70 of the fixed-field starter-generator 20. The engine 10 start conditions are met, for example, when the rider operates a start switch. Alternatively, the engine 10 start conditions are met, for example, when the rider operates the accelerator pedal while the engine is in an idling-stop state. In the engine start control (S13), the control device 60 powers the fixed-field starter-generator 20 with power discharged from the high-charge-acceptance lead battery 30 to apply torque to the stationary crankshaft 15. The control device 60 also records the execution period of the engine start control.

[0069] If the crankshaft 15 is rotating (Yes in S11), the assist condition is satisfied (Yes in S14), and the driving ratio condition is satisfied (Yes in S15), the control device 60 executes crankshaft rotation assist control (S16). To determine whether the assist condition is satisfied, the control device 60 uses, for example, an output signal from an accelerator sensor that detects operation of an accelerator grip (not shown). The assist condition may include, for example, the rotation speed of the engine 10 or the speed of the saddle-riding type vehicle 1. The driving ratio condition (S15) will be described later. In the crankshaft rotation assist control (S16), the control device 60 powers the fixed-field starter-generator 20 with power discharged from the high charge acceptance characteristic lead battery 30. This causes the control device 60 to apply torque in the direction of rotation of the rotating crankshaft 15. The control device 60 records the execution period of the crankshaft rotation assist control. If the crankshaft 15 is rotating (Yes in S11), the assist condition is not satisfied (No in S14), and the power generation condition is satisfied (Yes in S17), the control device 60 executes power generation control (S18). The control device 60 determines whether the power generation condition is satisfied based on, for example, the rotational speed of the crankshaft 15 and the voltage of the high charge acceptance lead battery 30. In the power generation control (S18), the control device 60 causes the fixed-field starter-generator 20, which receives torque from the crankshaft 15, to generate power. The high charge acceptance lead battery 30 is charged with the generated power. The control device 60 records the execution period of the power generation control. The operation ratio condition is whether the ratio of the period during which the power generation control (S18) is executed to the period during which the control (S13, S16) for powering the fixed-field starter-generator 20 with power discharged from the high charge acceptance lead battery 30 is executed exceeds a lower limit value. The lower limit value is set to be greater than 50% of the charge amount of the high charge acceptance lead battery 30. The lower limit value is obtained, for example, from measurement results of repeated charge and discharge tests of the high charge acceptance lead battery 30 under various conditions.

[0070] For example, if the ratio of the period during which the power generation control (S18) is executed is equal to or less than the lower limit, the operation ratio condition is not satisfied (No in S15), and execution of the assist control (S16) is prohibited. According to this embodiment, it is possible to prevent the charge amount of the high charge acceptance lead battery 30 from decreasing to 50% or less.

[0071] Furthermore, when the ratio of the period during which the power generation control (S18) is performed to the period during which the control (S13, S16) for powering the fixed-field starter-generator 20 is performed is equal to or less than a lower limit, the execution of the start control (S13) is not prohibited, but the execution of the assist control (S16) is prohibited. Therefore, even if the high charge acceptance characteristic lead battery 30 cannot be charged efficiently, it is possible to prevent a situation in which the engine 10 cannot be started.

[0072] [Fifth embodiment] Fig. 5 is a flowchart illustrating the operation of a control device according to a fifth embodiment. The flowchart in Fig. 5 differs from the flowchart in Fig. 4 in that it determines whether or not a charging condition is satisfied (S25) instead of the operation ratio condition (S15) in the flowchart in Fig. 4.

[0073] The control device 60 of this embodiment prohibits the execution of idling stop control when the charge amount of the high charge acceptance lead battery 30 is smaller than the assist lower limit. The control device 60 obtains the charge amount from the detection results of the output voltage and output current of the high charge acceptance lead battery 30, for example, when the idling stop control (S13) or the starting control (S13) is being executed. However, the method of obtaining the charge amount is not particularly limited, and for example, it may be obtained from the output voltage when the high charge acceptance lead battery 30 is not supplying power to the fixed field starter-generator 20. Furthermore, the charge amount may be obtained from the cumulative input / output current of the high charge acceptance lead battery 30.

[0074] If the charge amount of the high-charge-acceptance lead-acid battery 30 is less than the assist lower limit in step S25, the control device 60 determines that the charging condition is not met (No in S25) and prohibits execution of the crankshaft rotation assist control (S16). The assist lower limit is set to a value greater than 50%. According to this embodiment, it is possible to prevent the charge amount of the high-charge-acceptance lead-acid battery 30 from decreasing to 50% or less due to the crankshaft rotation assist control (S16). Therefore, the high-charge-acceptance lead-acid battery 30 can be charged with high efficiency even at a higher rotation speed of the crankshaft 15.

[0075] In this embodiment, when the charge amount of the high charge acceptance lead battery 30 is smaller than the assist lower limit, the execution of the start control (S13) is not prohibited, but the execution of the assist control (S16) is prohibited. Therefore, even if the high charge acceptance lead battery 30 cannot be charged efficiently, it is possible to prevent a situation in which the engine 10 cannot be started.

[0076] Elements in this embodiment other than those described above are common to the fourth embodiment, so the same reference numerals will be used for the elements common to the fourth embodiment, and the description thereof will be omitted.

[0077] Sixth Embodiment Fig. 6 is a flowchart illustrating the operation of a control device according to a sixth embodiment. The flowchart in Fig. 6 differs from the flowchart in Fig. 5 in that steps S31, S32, and S33 are added.

[0078] In this embodiment, the control device 60 executes the idling stop control (S33) when the crankshaft 15 is rotating (Yes in S11), the idling stop condition is met (Yes in S31), and the charging condition is met (Yes in S32). The idling stop condition is, for example, when the saddle-riding type vehicle 1 is stopped. The idling stop control (S33) stops the combustion operation of the engine 10 and stops the rotation of the crankshaft 15. The idling stop control (S33) puts the saddle-riding type vehicle 1 into an idling stop state. The engine 10 in the idling stop state starts when the starting condition is met (Yes in S12). When the charge amount of the high charge acceptance characteristic lead battery 30 is less than the assist lower limit (No in S32), the control device 60 prohibits the execution of the idling stop control (S33). According to this embodiment, it is possible to prevent the charge amount of the high charge acceptance lead battery 30 from decreasing to 50% or less due to the engine start control (S13) after the idling stop control (S33).

[0079] In this embodiment, when the charge amount of the high charge acceptance lead battery 30 is smaller than the assist lower limit, the execution of the start control (S13) is not prohibited, and the execution of the idling stop control (S33) is prohibited. Therefore, even if the high charge acceptance lead battery 30 cannot be charged efficiently, it is possible to prevent a situation in which the engine 10 cannot be started.

[0080] Elements in this embodiment other than those described above are common to the fifth embodiment, so the same reference numerals will be used for the elements common to the fifth embodiment, and the description thereof will be omitted.

[0081] In the fourth to sixth embodiments, the execution of the start control is not prohibited, but the execution of the assist control or the idling stop control is prohibited. However, the control is not particularly limited. For example, if the execution of the assist control or the idling stop control is prohibited, the execution of the start control may be prohibited. In this case, the decrease in the charge amount of the high charge acceptance characteristic lead battery 30 is further suppressed.

[0082] Furthermore, the control based on the charge amount of the fifth or sixth embodiment described above may be combined as a weighting condition with the operation ratio condition of the third embodiment. Furthermore, the techniques of the first to sixth embodiments may be combined with the first embodiment, and further, a combination of the following multiple embodiments may be combined with the first embodiment. A second embodiment relating to specific charge / discharge characteristics and a third embodiment relating to magnetic pole portions having a number greater than the number of teeth. A fourth embodiment relating to specific charge / discharge characteristics and an operation ratio condition. A fifth embodiment relating to specific charge / discharge characteristics and a charge amount. A sixth embodiment relating to specific charge / discharge characteristics and a prohibition of idling stop control. A fourth embodiment relating to specific charge / discharge characteristics and an operation ratio condition. A third embodiment relating to magnetic pole portions having a number greater than the number of teeth and an operation ratio condition. A fifth embodiment relating to a charge amount. A third embodiment relating to magnetic pole portions having a number greater than the number of teeth and an operation ratio condition. A fifth embodiment relating to a charge amount. A sixth embodiment relating to magnetic pole portions having a number greater than the number of teeth and an prohibition of idling stop control. A fourth embodiment relating to an operation ratio condition and an operation ratio condition. A fourth embodiment relating to an operation ratio condition and a sixth embodiment relating to prohibition of idling stop control. A second embodiment relating to a specific charge / discharge characteristic, a third embodiment relating to a number of magnetic pole portions greater than the number of teeth, and a fourth embodiment relating to an operation ratio condition. A second embodiment relating to a specific charge / discharge characteristic, a third embodiment relating to a number of magnetic pole portions greater than the number of teeth, and a fifth embodiment relating to a charge amount. A second embodiment relating to a specific charge / discharge characteristic, a third embodiment relating to a number of magnetic pole portions greater than the number of teeth, and a sixth embodiment relating to prohibition of idling stop control. A second embodiment relating to a specific charge / discharge characteristic, a fourth embodiment relating to an operation ratio condition, and a fifth embodiment relating to a charge amount. A second embodiment relating to a specific charge / discharge characteristic, a fourth embodiment relating to an operation ratio condition, and a sixth embodiment relating to prohibition of idling stop control. A second embodiment relating to a specific charge / discharge characteristic, a third embodiment relating to a number of magnetic pole portions greater than the number of teeth, a fourth embodiment relating to an operation ratio condition, and a fifth embodiment relating to a charge amount. A second embodiment relates to specific charge / discharge characteristics, a third embodiment relates to a number of magnetic pole portions greater than the number of teeth, a fourth embodiment relates to an operation ratio condition, and a sixth embodiment relates to prohibition of idling stop control.

[0083] 1: saddle-ride type vehicle 4: electrical path 10: engine 15: crankshaft 20: fixed-field starter-generator (starter-generator) 30: high charge acceptance characteristic lead battery (lead battery) 60: control device 70: rotor 77: permanent magnet 77a: magnetic pole portion 80: stator 85: teeth SL: slot ST: stator core W: winding

Claims

1. A control device comprising: a lead battery; a starter-generator that rotates the crankshaft of an engine to start the engine and generates electricity by being rotated by the crankshaft; and a control device that is provided in an electrical path electrically connecting the lead battery and the starter-generator and executes at least an engine start control that powers the starter-generator with power discharged from the lead battery to apply torque to the stationary crankshaft to start the engine, a crankshaft rotation assist control that powers the starter-generator with power discharged from the lead battery to apply torque in a direction to increase the rotation of the rotating crankshaft, and a power generation control in which the starter-generator receives torque from the crankshaft to generate power for charging the lead battery. The starter-generator is connected to the crankshaft at a fixed reduction ratio without a clutch, or is fixed to the crankshaft without a clutch, and is configured so that a rotor equipped with a permanent magnet rotates while the crankshaft is rotating, and is a fixed field magnet type starter-generator that is more likely to generate excessive electricity while the crankshaft is rotating compared to a variable field magnet type generator. A saddle-ride type vehicle, wherein the lead battery is a high charge acceptance lead battery having characteristics similar to a lead battery for a charge-controlled vehicle or a lead battery for an idling-stop vehicle designed to be charged with generated power controlled by varying the field magnet of the variable field magnet generator so as to be able to accept power generated by the fixed field magnet starter-generator, which is prone to generating excessive power while the crankshaft is rotating, and which has a characteristic of having higher charge acceptance performance than a lead battery for a normal vehicle, and wherein the control device controls the powering and power generation of the fixed field magnet starter-generator so that the high charge acceptance lead battery is used at a charge level greater than 50% when each of the crankshaft rotation assist control for powering the fixed field magnet starter-generator with power discharged from the high charge acceptance lead battery and the power generation control for charging the high charge acceptance lead battery with power generated by the permanent magnet rotated by the crankshaft is performed a plurality of times during the period when the crankshaft is rotating.

2. A saddle-type vehicle as described in claim 1, wherein the high charge acceptance characteristic lead battery has specific charge and discharge characteristics, and the specific charge and discharge characteristics are such that an integrated charge energy is greater than 200 As × the rated capacity / 5 Ah when the high charge acceptance characteristic lead battery is discharged from a fully charged state at a 10-hour rate current with power equal to the rated capacity of the high charge acceptance characteristic lead battery, and then charged with power equal to 70% of the rated capacity × 5 Ah of the rated capacity at a 10-hour rate current, and then left for a further 20 hours, and then charged for 60 seconds at a 1 / 3-hour rate current under conditions of 25°C, and the control device controls the power running and power generation of the fixed field type starter generator so that the high charge acceptance characteristic lead battery having the specific charge and discharge characteristics is used with a charge amount greater than 50% when the crankshaft rotation assist control and the power generation control are each executed multiple times.

3. A saddle-type vehicle as claimed in claim 1 or 2, wherein the fixed field type starter-generator comprises a stator core having a plurality of teeth in which a plurality of slots are formed at intervals in the circumferential direction of the fixed field type starter-generator, and a stator having windings arranged to pass through the slots, and the rotor has a plurality of magnetic pole portions constituted by the permanent magnets, and the number of the magnetic pole portions is greater than the number of the teeth.

4. A saddle-type vehicle as claimed in any one of claims 1 to 3, wherein the control device executes control so that the ratio of a period during which the starter-generator receives torque from the crankshaft and executes control to generate power for charging the lead battery to a period during which the starter-generator executes control to power the starter-generator with power discharged from the lead battery exceeds a lower limit value set so as to make the charge amount of the high charge acceptance characteristic lead battery greater than 50%.

5. A saddle-type vehicle as claimed in any one of claims 1 to 4, wherein the control device prohibits the execution of the crankshaft rotation assist control when the charge amount of the high charge acceptance characteristic lead battery is less than an assist lower limit value set as a value greater than 50%.

6. A saddle-type vehicle as described in any one of claims 1 to 5, wherein the control device executes idling stop control to stop the combustion operation of the engine when a predetermined idling stop condition is met, and prohibits execution of the idling stop control when the charge amount of the high charge acceptance characteristic lead battery is less than an assist lower limit value set to a value greater than 50%.

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