Straddled vehicle

Abstract

The present invention addresses the problem of increasing the degree of freedom of assist control while reducing degradation of the lifespan of a lead-acid battery of a straddled vehicle. This straddled vehicle is provided with a lead-acid battery and a control device. The lead-acid battery is a high charge acceptance characteristic lead-acid battery having a characteristic of higher charge acceptance performance compared to a regular vehicle lead-acid battery. The control device controls powering of a fixed field type starter generator and power generation such that, when each of a crankshaft rotation assist control for powering the fixed field type starter generator by electricity discharged from the high charge acceptance characteristic lead-acid battery and a power generation control for charging the high charge acceptance characteristic lead-acid battery by electricity generated by a permanent magnet rotated by a crankshaft is executed a plurality of times during a period when the crankshaft is rotating, a charge amount of the high charge acceptance characteristic lead-acid battery is within a usage range exceeding 50%, and including a range less than 80%.

Description

Straddled Vehicle

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

[0002] As an example of a straddle-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 powers the starter-generator with power discharged from the lead battery and applies torque in the rotational direction of the crankshaft of the engine in combustion operation. In power generation control, the starter-generator receives torque from the crankshaft and generates power to charge the lead battery.

[0003] For example, Patent Document 2 also discloses a motorcycle equipped with a battery, a starter generator, and a control device. The control device in Patent Document 2 performs a starting operation and an assist operation. Patent Document 2 also discloses voltage control when a lithium-ion battery is connected as the battery (see FIG. 6 of Patent Document 2) and voltage control when a lead battery is connected (see FIG. 8 of Patent Document 2).

[0004] Patent No. 5857624 Patent Publication No. 2020-131934

[0005] It is sometimes desirable for a saddle-ride type vehicle to be able to increase the number of assists or the strength of the assist, or to increase both the number of assists or the strength of the assist, while making the vehicle body compact by making the components used for the assist operation compact and suppressing a decrease in the lifespan of the lead battery. In other words, it is sometimes desirable for a saddle-ride type vehicle to be able to increase the degree of freedom in assist control, while making the vehicle body compact and suppressing a decrease in the lifespan of the lead battery.

[0006] An object of the present invention is to increase the degree of freedom in assist control while making the vehicle body compact and suppressing a decrease in the lifespan of a lead battery in a saddle-ride type vehicle.

[0007] The present inventors have considered a method for increasing the degree of freedom in assist control while making the vehicle body compact and suppressing the shortening of the life of the lead battery.

[0008] The inventors have found that, for example, in a configuration such as that shown in Patent Document 1, increasing the number of assists or the strength of the assist when assist and charging are repeated may shorten the lifespan of the lead battery. The power output from the lead battery is power charged into the lead battery by previous power generation by the starter-generator. Saddle-type vehicles, which turn with the rider's weight shift, are required to have a compact body, and fixed-field starter-generators, which are smaller than alternators installed in automobiles, are installed. Fixed-field starter-generators are permanent magnet starter-generators. Fixed-field starter-generators are 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 fixed-field starter-generator to generate more power. In contrast, batteries that store electricity, i.e., lead batteries for conventional automobiles typically used to start the engine of a saddle-type vehicle, have poor charge acceptance compared to their power output performance. As a result, the power generated by a fixed-field starter-generator may be excessive relative to the charge acceptance capacity of the standard lead-acid battery. The excessive power generated by a fixed-field starter-generator is not charged but is wasted, for example, as heat and electrolyte evaporation. Therefore, as the number of assist cycles or the strength of the assist increase, the next assist cycle occurs more frequently before the power discharged during the assist cycle is replenished with charge, resulting in a continuous decrease in the charge level of the standard lead-acid battery. Using a standard lead-acid battery with a low charge level often shortens its lifespan. For example, Patent Document 2 (Patent Document 2) suggests that when using a standard lead-acid battery, the charge level is controlled with a target of 100%. A graph in Patent Document 2 shows a range of charge level control from 80% to 100%. Because standard lead-acid batteries have low charge acceptance capacity, allowing a low charge level can easily result in the charge level continuing to decrease due to the inability to fully recover through subsequent charge control.

[0009] Patent Document 2 discloses a range of charge levels below 80%, for example, a range from 40% to 60% with 50% at the center. However, the range of charge levels below 80% in Patent Document 2 is only applicable when a lithium-ion battery is installed. This is because lithium-ion batteries have the property of extending their lifespan by avoiding full charge when being charged (see, for example,

[0022] of Patent Document 2). Furthermore, the lithium-ion battery in Patent Document 2 maintains a chargeable space for the purpose of generating braking force by charging regenerative power generated at any time. Lithium-ion batteries have a higher charge acceptance capacity than lead-acid batteries for standard vehicles. However, lithium-ion batteries are required to be used in a manner that avoids full charge. Furthermore, the output current characteristics of lithium-ion batteries generally tend to be lower than those of lead-acid batteries for standard vehicles with the same capacity. For this reason, vehicles with an assist function and equipped with a lithium-ion battery often install a lead-acid battery in addition to the lithium-ion battery. Installing both a lithium-ion battery and a lead-acid battery increases the vehicle size of the straddle-type vehicle.

[0010] The inventors considered adopting a high-charge-acceptance lead-acid battery, which is a lead-acid battery with higher charge acceptance than a lead-acid battery for a standard vehicle, in order to accept more power generated by a fixed-field 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. Batteries for charge-controlled vehicles are disclosed, for example, on the web pages "Batteries for Charge-Controlled Vehicles" and "Batteries for Idling-Stop Vehicles," available at https: / / gyb.gs-yuasa.com / products / . Lead-acid batteries for idling-stop vehicles are, for example, batteries specified in Japanese Industrial Standard JIS D 5306:2021. Lead-acid batteries for charge-controlled vehicles and lead-acid batteries for idling-stop vehicles are also disclosed in, for example, Japanese Patent Application Laid-Open Publication Nos. 2013-134957, 2014-192079, and 2016-058238.

[0011] By charging a high-charge-acceptance lead-acid battery with the large amount of power generated by a compact, magnet-based fixed-field starter-generator, 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 utilizes the power of the fixed-field starter-generator with high efficiency and is charged in a shorter time. For example, the charge level of a high-charge-acceptance lead-acid battery discharged during assist can be restored more quickly. For example, even if a high-charge-acceptance lead-acid battery is discharged to a charge level below 80%, it can be restored in a short charging time. Therefore, the number of assists or the strength of the assist can be increased. This allows for a wider range of settings for the number of assists or the strength of the assist, or for both the number of assists and the strength of the assist.

[0012] However, when the inventors conducted assist and charging tests simulating actual driving conditions using a combination of a fixed-field 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. Further investigation 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. Further investigation 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.

[0013] Therefore, the inventors have devised a method for controlling the power running and power generation of a fixed-field starter-generator so that the charge level of a high-charge-acceptance lead-acid battery is within a range of use that is greater than 50%, including a range that is less than 80%. This makes it possible to improve the charge acceptance of a high-charge-acceptance lead-acid battery compared to a standard automotive lead-acid battery with an equivalent capacity. This makes it possible to suppress a decrease in the lifespan of the high-charge-acceptance lead-acid battery.

[0014] In this way, the inventors devised a system for charging the power generated by a fixed-field starter-generator with a high-charge-acceptance lead-acid battery, and controlling the power generation and running of the fixed-field starter-generator so that the charge level of the high-charge-acceptance lead-acid battery is within a usable range of more than 50%, including a range of less than 80%. In this case, the high-charge-acceptance lead-acid battery can accept the large amount of power generated by a compact fixed-field starter-generator without a field winding, without the need for a lithium-ion battery, for example, and quickly recover its charge level. Furthermore, because the high-charge-acceptance lead-acid battery can be discharged to a range of less than 80% charge, the fixed-field starter-generator can provide strong assist power or more frequent assist operation without a dedicated assist motor. This allows for a compact vehicle body, minimizes the shortening of the life of the high-charge-acceptance lead-acid battery, and increases the flexibility of assist control.

[0015] A saddle-type vehicle according to each aspect of the present invention based on the above findings has the following configuration.

[0016] (1) A control device comprising: a lead battery; an engine having a crankshaft and rotating the crankshaft by a combustion operation; a starter-generator that starts the engine by rotating the crankshaft of 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 electric power discharged from the lead battery during a period when the combustion operation of the engine is stopped, thereby applying torque to the crankshaft, thereby starting the engine; a crankshaft rotation assist control that powers the starter-generator with electric power discharged from the lead battery during the combustion operation of the engine, thereby applying torque in the rotational direction of the rotating crankshaft; and a power generation control that causes the starter-generator to receive torque from the crankshaft and generate electric power for charging the lead battery. The starter-generator is a fixed-field magnet type starter-generator that 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 rotates, and is more likely to generate excessive power while the crankshaft rotates compared to a variable field magnet type generator. the lead battery is a high charge acceptance lead battery having the same charge acceptance performance as a lead battery for a charge-controlled vehicle or a lead battery for an idle-stop vehicle, which is designed to be charged with generated power controlled by varying the field of the variable field 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 the control device controls the power running and power generation of the fixed-field magnet starter-generator so that the charge amount of the high charge acceptance lead battery is within a usage range of more than 50%, including a range of less than 80%, when the control device performs each of the crankshaft rotation assist control, which powers the fixed-field magnet starter-generator with power discharged from the high charge acceptance lead battery, and the power generation control, which charges the high charge acceptance lead battery with power generated by the permanent magnet rotated by the crankshaft, multiple times during the period when the engine is operating in combustion mode.

[0017] The straddle-type vehicle (1) includes an engine, a lead battery, a starter-generator, and a control device. The lead battery is a high-charge-acceptance lead battery. The starter-generator is a fixed-field starter-generator that generates a field using a permanent magnet. The fixed-field starter-generator is more compact than a variable-field generator, such as an alternator with a field winding. Furthermore, since the fixed-field starter-generator is shared for both power generation control and crankshaft rotation assist control, it is more compact than, for example, a generator equipped with a dedicated motor for assist. However, when the engine is operating and the straddle-type vehicle is traveling, the amount of power generated by the fixed-field starter-generator tends to be excessive compared to the amount of power generated by a variable-field generator, such as an alternator that can variably control the field by the current in the field winding. The high-charge-acceptance lead battery is a battery that has the same charge acceptance performance as a lead battery for a charge-controlled vehicle or a lead battery for an idle-stop vehicle. Here, the lead-acid battery for charge-controlled vehicles or the lead-acid battery for idle-stop vehicles is designed to be charged with power generated by a variable field magnet generator. The high-charge-acceptance lead-acid battery can reduce the waste of power generated by a fixed-field starter-generator. Because the high-charge-acceptance lead-acid battery has the same charge acceptance performance as the lead-acid battery for charge-controlled vehicles or the lead-acid battery for idle-stop vehicles, it can accept and store the large amount of power generated by the fixed-field starter-generator. This allows the vehicle body to be more compact than, for example, a vehicle equipped with a lithium battery designed to accept a large current separately from the lead-acid battery for normal vehicles. The control device, through crankshaft rotation assist control, powers the fixed-field starter-generator with power discharged from the high-charge-acceptance lead-acid battery to apply torque in the direction of crankshaft rotation. Furthermore, through power generation control, the control device controls the fixed-field starter-generator to receive torque from the crankshaft and generate power to charge the lead-acid battery. A control device provided in an electrical path electrically connecting the high charge acceptance lead battery and the fixed field starter-generator executes crankshaft rotation assist control and power generation control multiple times each.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 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 assist can be charged in a shorter time. This allows for an increase in the number of assist operations or the strength of the assist. Furthermore, when the control device executes multiple crankshaft rotation assist control, which powers the fixed-field starter-generator with power discharged from the high-charge-acceptance lead-acid battery, and multiple power generation control, which charges the high-charge-acceptance lead-acid battery with power generated by the rotating permanent magnet, respectively, the control device controls the powering and power generation of the fixed-field starter-generator so that the charge level of the high-charge-acceptance lead-acid battery is within a usable range. Here, the usable range is a charge level range greater than 50%. In other words, the control device controls the powering and power generation so that the charge level does not fall below 50%. The usable range also includes a range less than 80%. According to the configuration (1), the charge acceptance of a high-charge-acceptance lead-acid battery charged with power generated by a fixed-field starter-generator can be improved compared to that of a standard vehicle lead-acid battery with the same capacity. By charging the high-charge-acceptance lead-acid battery with the high-charge-acceptance power generated by the fixed-field starter-generator, the portion of the high-charge-acceptance power generated by the fixed-field starter-generator that is wasted as heat or the like is reduced, thereby increasing the charging current of the high-charge-acceptance lead-acid battery after discharge during assist. In other words, the high-charge-acceptance lead-acid battery efficiently utilizes the power of the fixed-field starter-generator and is charged in a shorter time. For example, even if the high-charge-acceptance lead-acid battery is discharged to less than 80% charge during assist, it is likely to recover quickly. Therefore, the number of assists or the strength of assist can be increased. This allows for a wider range of settings for the number of assists or the strength of assist, or for both the number of assists and the strength of assist. Furthermore, the power running and power generation of the fixed field starter-generator are controlled so that the charge amount of the high charge acceptance lead battery is within a usable range greater than 50%.This allows the charge acceptance of the high charge acceptance lead battery to be higher than that of a standard lead battery for a vehicle with the same capacity, thereby preventing a decrease in the lifespan of the high charge acceptance lead battery.

[0018] Therefore, with the configuration of (1), the high-charge-acceptance lead-acid battery can accept the large amount of power generated by a compact, fixed-field starter-generator without a field winding, and can quickly recover its charge without the need for an additional lithium-ion battery, for example. Furthermore, because the high-charge-acceptance lead-acid battery can be discharged to a charge level of less than 80%, the fixed-field starter-generator can provide strong assist power or assist operation frequently without a dedicated assist motor. This allows the body of the saddle-type vehicle to be made compact, while suppressing a decrease in the lifespan of the high-charge-acceptance lead-acid battery and increasing the degree of freedom in assist control.

[0019] (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 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 further charged at a 10-hour rate current with power equal to 70% of the rated capacity x 5 Ah of the rated capacity, 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, the integrated charged energy is greater than 200 As x 5 Ah of the rated capacity, and the control device controls the power running and power generation of the fixed-field starter generator so that the charge amount of the high charge acceptance characteristic lead battery having the specific charge and discharge characteristics is within a usage range greater than 50%, including a range less than 80%, when the crankshaft rotation assist control and the power generation control are each executed multiple times.

[0020] According to the configuration (2), for example, it is possible to easily select a high-charge-acceptance lead-acid battery that can increase the number of assists, the strength of the assist, or both the number of assists and the strength of the assist, using the characteristics of the integrated charge energy obtained by the specific measurement method as an index. 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 within a usage range of more than 50%, including a range of less than 80%, 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.

[0021] (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.

[0022] According to the configuration (3), the angular velocity relative to the rotor rotational 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 pole portions. When the angular velocity is high, the impedance of the winding is high. Furthermore, the angular velocity increases further as the rotor rotational speed increases. The impedance of the winding impedes the current flowing through the winding. Therefore, while the induced voltage increases as the rotor rotational speed increases, the large impedance of the winding suppresses the 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 rotational speed than when the number of magnetic pole portions is smaller than the number of teeth.

[0023] (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%.

[0024] 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.

[0025] (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%.

[0026] 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.

[0027] (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%.

[0028] 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, and therefore it is possible to charge the high charge acceptance lead battery with high efficiency even at a higher crankshaft rotation speed.

[0029] 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 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.

[0030] A straddled vehicle is a vehicle in which the driver sits astride a saddle. Examples of straddled vehicles include scooters, mopeds, off-road vehicles, and on-road motorcycles. Furthermore, straddled vehicles are not limited to motorcycles, but may also include, for example, three-wheeled motor vehicles and all-terrain vehicles (ATVs). Three-wheeled motor vehicles 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. This allows the vehicle configured to be able to turn in a lean position to resist 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.

[0031] 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.

[0032] 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 that applies torque in the rotational direction of a rotating crankshaft. The assist function of the starter-generator typically applies torque in a direction that increases the rotational speed of the crankshaft. The assist function of the starter-generator may also be a function that suppresses a decrease in the rotational speed of the crankshaft when traveling uphill, for example. The starter-generator in the present disclosure is a fixed-field starter-generator. The starter-generator has, for example, a number of magnetic pole portions that is greater than the number of teeth. However, the starter-generator is not particularly limited and may have a number of magnetic pole portions that is equal to or less than the number of teeth.

[0033] A fixed-field starter-generator is a starter-generator with a fixed field strength. For example, a fixed-field starter-generator is a permanent magnet 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 equipped 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. Simply put, the power output from a fixed-field starter-generator increases with the rotational speed during power generation. 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. A fixed-field starter-generator generating more power than 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 lead battery with high charge acceptance characteristics.

[0034] The control device executes at least engine start control, crankshaft rotation assist control, and power generation control. The control device may execute controls other than engine start control, crankshaft rotation assist control, and power generation control, for example. The control device may execute regeneration control, for example. 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.

[0035] In crankshaft rotation assist control, the control device powers the starter generator with power discharged from the lead battery while the crankshaft is rotating, and applies torque in the rotational direction of the rotating crankshaft, i.e., in the forward direction. 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.

[0036] A high charge acceptance lead battery is a lead battery that has the same charge acceptance as a lead battery for a charge-controlled vehicle or a lead battery for an idle-stop vehicle. A high charge acceptance lead battery has a higher charge acceptance 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 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 specifications outside the above numerical ranges may be acceptable as long as the battery has a higher charge acceptance than a standard vehicle lead battery. The maximum charging voltage of a high charge acceptance lead battery is, for example, 18 V. The nominal voltage of the high charge acceptance lead battery is, for example, 12 V. If the maximum charging voltage of the high charge acceptance lead battery is 18 V or the nominal voltage is 12 V, this can be achieved with a single commercially available lead battery for charge-controlled vehicles or lead battery for idle-stop vehicles. In this case, the power supply is more compact than, for example, a case where a nominal voltage of 24 V is achieved with two batteries. If a saddle-type vehicle has only one high charge acceptance lead battery and uses the same battery for starting control, crankshaft rotation assist control, and power generation control, the vehicle body can be made compact while increasing the degree of freedom in assist control. If a saddle-type vehicle also uses the above-mentioned high charge acceptance lead battery as a power source for electric accessories, the vehicle body can be made more compact than when a dedicated battery for the accessories is installed.

[0037] The lead-acid battery for a normal vehicle is, for example, a starting battery. The lead-acid battery for a normal vehicle has a charge acceptance performance lower than that of a lead-acid battery for a charge-controlled vehicle. The lead-acid battery for a normal vehicle also has a charge acceptance performance lower than that of a lead-acid battery for an idle-stop vehicle. The lead-acid battery for a normal vehicle is, for example, a starting battery specified in Japanese Industrial Standard JIS D 5301:2019.

[0038] 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). Maintaining the charge amount of a high-charge-acceptance lead-acid battery within a usage range greater than 50%, including a range less than 80%, means that the high-charge-acceptance lead-acid battery is maintained at a charge amount greater than 50% during both charging and discharging. The assist lower limit is, for example, the lower limit of the usage range. Maintaining the charge amount of a high-charge-acceptance lead-acid battery within a usage range greater than 50%, including a range less than 80%, means, for example, that the high-charge-acceptance lead-acid battery is used so that its charge amount does not fall below 50% during both charging and discharging. Maintaining the charge amount of a high-charge-acceptance lead-acid battery within a usage range greater than 50%, including a range less than 80%, means, for example, that the high-charge-acceptance lead-acid battery is used so that its charge amount does not fall below 50% during both charging and discharging. A charge amount less than 50% is not included in the usage range. The range of use may naturally include a charge amount between 80% and 100%.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] Hereinafter, the present invention will be described based on an embodiment with reference to the drawings.

[0043] [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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] The starter-generator 20 is a fixed-field starter-generator. 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 used for starting, assisting, and powering the engine 10, and is therefore more compact than, for example, a motor dedicated to assisting. 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 the current flowing through the field winding. An example of a variable-field generator is an alternator. Because the fixed-field starter-generator 20 does not have a field winding, it is more compact than, for example, an alternator. Unlike, for example, a variable-field generator having 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 magnitude of the magnetic field is set so as to output power for starting the engine 10, for example. The fixed-field starter-generator 20 cannot reduce the magnitude of the magnetic field through electrical control. In other words, even when the fixed-field starter-generator 20 rotates at high speed, the magnitude of the magnetic field cannot be reduced. For this reason, the fixed-field starter-generator 20 is more likely to generate excessive power while the crankshaft 15 is rotating than a variable-field generator.

[0048] 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 the same charge acceptance characteristic as a lead battery for a charge-controlled vehicle or a lead battery for an idle-stop vehicle. Therefore, the high charge acceptance lead battery 30 can accept a portion of the power generated by a fixed-field starter-generator 20 while the crankshaft 15 is rotating, which was previously considered excessive. Note that the lead battery for a charge-controlled vehicle is a lead battery originally designed to be charged with power generated by varying the field of the vehicle's variable-field generator.

[0049] 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 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.

[0050] 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 amount exceeds 50%. In other words, in the region where the charge amount 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 amount 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 high charge acceptance lead battery 30 is structured to maintain a capacity equivalent to that of a lead battery for a normal vehicle, while distributing charge acceptance performance to obtain high charge acceptance performance in specific areas.

[0051] 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, 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, applying torque to the crankshaft 15 of the engine 10, whose combustion operation is stopped. This starts the engine 10.

[0052] 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, thereby applying torque in the rotational direction of the crankshaft 15 of the engine 10 in combustion operation. This can increase the rotational speed of the crankshaft 15, for example, or suppress a decrease in the rotational speed of the crankshaft 15 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.

[0053] The control device 60 controls the power running and power generation of the fixed-field starter-generator 20 when crankshaft rotation assist control and power generation control are each executed multiple times while the crankshaft 15 is rotating. The control device 60 controls the power running and power generation of the fixed-field starter-generator 20 so that the charge amount of the high charge acceptance lead battery 30 is within usage range B greater than 50% during the above-mentioned period. Usage range B is set up to a charge amount less than 80%. More specifically, usage range B is set to cover both a charge amount less than 80% and a charge amount greater than 80%. The control device 60 controls the power running and power generation so that the high charge acceptance lead battery 30 can be used even when the charge amount is less than 80%.

[0054] As a control method, for example, a method of controlling the period 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. Also, 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 the assist lower limit value Bb 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.

[0055] The charge amount of the high charge acceptance lead battery 30 is within the usage range B, which is greater than 50%. Therefore, the charge 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 maintained higher than that of a standard vehicle lead battery having the same capacity. Therefore, the high charge acceptance lead battery 30 reduces the amount of wasted power from the power supplied from the fixed-field starter-generator 20. Therefore, the high charge acceptance lead battery 30, after being discharged by the assist, can be charged with more power than a standard vehicle lead battery, while suppressing a decrease in its lifespan.

[0056] 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.

[0057] 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, .... The charge amount also decreases due to the crankshaft rotation assist control. There is no substantial 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 crankshaft rotation assist control, the charge amount increases due to charge control. The high charge acceptance lead battery 30 of this embodiment has higher charge acceptance performance than a standard vehicle lead battery, and therefore the charge amount increases more per unit time during charge control.

[0058] As shown by the dashed line P, the charge level of the lead-acid battery for a standard vehicle increases only slightly per unit time during the charge control. Uncharged power is discarded. Therefore, when the crankshaft rotation assist control and the charge control are performed multiple times, the charge level of the lead-acid battery for a standard vehicle may decrease excessively, as shown by the dashed line P. An excessive decrease in the charge level shortens the life of the lead-acid battery for a standard vehicle. To prevent an excessive decrease in the charge level of the lead-acid battery for a standard vehicle, for example, a method of shortening the period during which the crankshaft rotation assist control is performed may be adopted. The dashed line Q shows the change in the charge level of the lead-acid battery for a standard vehicle when the period during which the crankshaft rotation assist control is performed is shortened. The crankshaft rotation assist control is initiated depending on the riding condition or the rider's operation, so its initiation timing cannot be predicted in advance. To prepare for the unpredictable crankshaft rotation assist control and to prevent an excessive decrease in the charge level due to a small increase in the charge level, the lead-acid battery for a standard vehicle is required to be kept substantially close to full charge. Therefore, the period of the crankshaft rotation assist control is shortened to a1, a2, . . .

[0059] In contrast, the high charge acceptance lead battery 30, which has high charge acceptance performance, can accept even more current from the fixed-field starter-generator 20, which would otherwise be discarded as heat or other waste if a standard vehicle lead battery were unable to accept the excess current. In other words, the high charge acceptance lead 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 power generation control period. As a result, the high charge acceptance lead battery 30 is charged in a shorter time. Therefore, while suppressing a reduction in the lifespan of the high charge acceptance lead battery 30, the assist time, number of assists, or strength of assist can be increased compared to a standard vehicle lead battery. In other words, the number of assists or strength of assist can be increased, or both the number of assists and 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 strength of assist, depending on, for example, the vehicle specifications. Furthermore, the power running and power generation of the fixed-field starter-generator 20 are controlled so that the charge amount of the high charge acceptance lead battery 30 is within usage range B. Usage range B is a range of charge rates greater than 50%. Usage range B also includes a range of charge rates less than 80%. By controlling the charge amount of the high charge acceptance lead battery 30 within usage range B, the charge acceptance performance of the high charge acceptance lead battery 30 can be further improved. Therefore, the shortening of the life of the high charge acceptance lead battery can be suppressed. Therefore, with the saddle-type vehicle 1, the vehicle body can be made compact, the shortening of the life of the high charge acceptance lead battery 30 can be suppressed, and the degree of freedom in assist control can be increased.

[0060] [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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] Third Embodiment FIG. 3 is a cross-sectional view showing a fixed-field starter-generator according to a third embodiment.

[0065] 3 includes a rotor 70 and a stator 80. The rotor 70 always rotates in conjunction with the rotation of the crankshaft 15.

[0066] 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.

[0067] 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.

[0068] The rotor 70 has magnetic pole portions 77a whose number is greater than the number of teeth 85. In the example shown in FIG.

[0069] 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 electrical angular velocity 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.

[0070] 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.

[0071] Fourth Embodiment FIG. 4 is a flowchart illustrating the operation of a control device according to a fourth embodiment.

[0072] If the engine 10 is not in combustion operation (No in S11) and the engine 10 start condition is satisfied (Yes in S12), the control device 60 executes engine start control (S13). To determine whether the engine 10 is in combustion operation, 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 condition is satisfied, for example, when the rider operates a start switch. Alternatively, the engine 10 start condition is satisfied, for example, when the rider operates the accelerator grip while the engine is in an idle-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.

[0073] If the engine 10 is in combustion operation (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 rotational direction of the rotating crankshaft 15. The control device 60 records the execution period of the crankshaft rotation assist control. If the engine 10 is in combustion operation (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 predetermined lower limit. The lower limit value is set so that the charge amount of the high charge acceptance lead battery is used within the usage range B. The usage range B is set to a range of charge amounts greater than 50% and also to include a range of charge amounts less than 80%. 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.

[0074] 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.

[0075] 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.

[0076] [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.

[0077] 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 value Bb (see part (b) of Figure 1). 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 executing the idling stop control (S33) or the starting control (S13). 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 also be obtained from the accumulation of the input and output current of the high charge acceptance lead battery 30.

[0078] If the charge amount of the high-charge-acceptance lead-acid battery 30 is less than the assist lower limit Bb in step S25, the control device 60 determines that the charging condition is not satisfied (No in S25) and prohibits execution of the crankshaft rotation assist control (S16). The assist lower limit Bb 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.

[0079] In this embodiment, when the charge amount of the high charge acceptance lead battery 30 is smaller than the assist lower limit value Bb, 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 the engine 10 from being unable to start.

[0080] 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.

[0081] [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.

[0082] 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. Note that the engine 10 in the idling stop state starts when the starting condition is met (Yes in S12). The control device 60 prohibits the execution of the idling stop control (S33) when the charge amount of the high charge acceptance characteristic lead battery 30 is less than the assist lower limit value Bb (No in S32). 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).

[0083] In this embodiment, when the charge amount of the high charge acceptance lead battery 30 is smaller than the assist lower limit value Bb, 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.

[0084] 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.

[0085] 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.

[0086] 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. Furthermore, the first embodiment may be combined with a combination of the following multiple embodiments. 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 a charge amount. A third embodiment relating to magnetic pole portions having a number greater than the number of teeth and a charge amount. A sixth embodiment relating to the prohibition of idling stop control. A fourth embodiment relating to an operation ratio condition and a charge amount. 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.

[0087] 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 system comprising: a lead battery; an engine having a crankshaft and rotating the crankshaft by performing combustion operation; 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 executes at least an engine start control that powers the starter generator with electric power discharged from the lead battery during a period when the combustion operation of the engine is stopped to apply torque to the crankshaft and start the engine, a crankshaft rotation assist control that powers the starter generator with electric power discharged from the lead battery during the combustion operation of the engine to apply torque in the rotational direction of the rotating crankshaft, and a power generation control that causes the starter generator to receive torque from the crankshaft and generate electric power for charging the lead battery, A saddle-type vehicle, in which 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 such that a rotor having a permanent magnet rotates while the crankshaft is rotating, and is a fixed-field magnet starter-generator that is more likely to generate excessive power while the crankshaft is rotating compared to a variable field magnet generator. a control device for controlling the power supply to the fixed field magnet starter-generator using the power discharged from the high charge acceptance characteristic battery and the power generation control for charging the high charge acceptance characteristic battery using the power generated by the permanent magnet rotated by the crankshaft, the control device ...

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 x 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 x 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 charge amount of the high charge acceptance characteristic lead battery having the specific charge and discharge characteristics is within a usage range greater than 50%, including a range less than 80%, when the crankshaft rotation assist control and the power generation control are each executed a plurality of 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%.