Straddled Vehicle

Abstract

The purpose of the present invention is to provide a straddled vehicle with which it is possible to shorten the time required to start an engine while minimizing any increase in size. The straddled vehicle comprises a variable load four-stroke engine, a permanent-magnet-type synchronous motor, an inverter having a plurality of switching units, and a control device. When a start instruction is input while a rotor is not rotating, the control device controls the plurality of switching units so as to change the plurality of switching units in order from a zero output state to a low output state and a high output state. The high output state is a state in which the plurality of switching units are controlled such that the rotation of the rotor accelerates. The low output state is a state in which, for a period during which the rotor rotates at an angle smaller than a rotation angle corresponding to one of a plurality of magnetic pole pairs, the plurality of switching units are controlled so as to make the output of the permanent-magnet-type synchronous motor greater than the zero output state and less than the high output state. Before and after the transition to the high output state, the rotation of the rotor and the positive / negative patterns of the currents flowing through the windings of the multiple phases of the switching units continue.

Description

[Technical field]

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

[0002] As a straddle-type vehicle, there is a vehicle equipped with a load-varying four-stroke engine that has a high load region where the load for rotating the engine's crankshaft is high and a low load region where the load for rotating the crankshaft is low during the four-stroke period. Such a load-varying four-stroke engine requires a large output torque from the motor for starting the engine in order to rotate the crankshaft beyond the high load region when starting the engine. However, if the output torque of the motor is to be increased, the motor becomes larger. This results in a larger straddle-type vehicle.

[0003] In order to rotate the crankshaft beyond the high load region at engine start while suppressing an increase in the size of the motor, it is conceivable to provide a run-up section from the start of rotation of the crankshaft to the position of the high load region. For example, Patent Document 1 shows a saddle-type vehicle equipped with a variable-load four-stroke engine having a high-load region and a low-load region between the four strokes. The control device of the saddle-type vehicle in Patent Document 1 causes the motor to start rotating the crankshaft in response to a start command input, and accelerates the rotation of the crankshaft in a run-up section until the high-load region is reached. In a saddle-type vehicle such as that shown in Patent Document 1, an attempt is made to shorten the time it takes to start by using both the large inertial force associated with a high rotation speed and the output torque of the motor to overcome the high-load region. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2015 / 093576 Summary of the Invention [Problem to be solved by the invention]

[0005] In saddle-type vehicles, it is desirable to reduce the time it takes to start the engine while keeping the vehicle size small.

[0006] An object of the present invention is to provide a saddle-type vehicle that can reduce the time it takes to start the engine while preventing an increase in size. [Means for solving the problem]

[0007] In further studying the time required for startup, the inventors focused on the output of the motor at the start of rotation. The rotor has magnetic pole pairs. The rotor with the magnetic pole pairs receives a rotational force from a magnetic field formed by currents flowing through the windings of each phase of the stator. The rotor rotates in response to periodic changes in the currents flowing through the windings of each phase, generating motor output. When current begins to be supplied to the windings while the rotor is stopped, the rotor's orientation may differ from the ideal orientation for generating a torque from the magnetic field formed by the current flowing through the windings of each phase. The ideal orientation is the orientation that maximizes the torque that the rotor receives from the magnetic field. If the rotor orientation is different from the ideal position, the rotational force acting on the rotor when it starts to rotate may be restricted or a reverse rotational force may be acting on the rotor, causing a period in which the rotor does not follow the rotation of the magnetic field. In other words, the rotational force acting on the stopped rotor is different from that acting when it is in the ideal position. In this case, there is a delay in the time it takes for the rotor to start accelerating. As a result, there is a delay in the time it takes for the crankshaft to rotate into the high load region. The amount of delay varies depending on the orientation of the stopped rotor, so the time it takes to start the engine varies from start to start. The average engine start time is increased by the delay.

[0008] The inventor has found that, when a start command is input, a current is first passed through the windings so that a relatively small output is output during a period in which the rotor in a stopped state rotates at an angle smaller than the rotation angle corresponding to one of the magnetic pole pairs, thereby suppressing the variation in the engine start time. More specifically, when a start command is input, a current is first passed through the windings so that a small output is output during a period in which the rotor in a stopped state rotates at an angle smaller than the rotation angle corresponding to one of the magnetic pole pairs in a low output state. This suppresses the fluctuation in the rotation of the rotor even if the orientation of the stopped rotor is different from the ideal orientation. For example, even if a reverse rotation force is generated in the rotor, the rotation force is suppressed. Therefore, in a high output state following a low output state, when the positive and negative currents of each phase are switched while a current that increases the output is passed, the rotor is likely to follow the magnetic field formed in the high output state. On the other hand, when the orientation of the rotor is ideal, the rotor can receive the rotation force by immediately following the orientation of the magnetic field formed by the current in the low output state. This reduces variation in the time it takes to start the engine, and therefore, compared to a case in which a current is not passed through the windings so as to output a relatively small output, the time it takes to start the engine can be shortened without increasing the size of the motor.

[0009] In order to solve the above-mentioned problems, the present invention employs the following configuration.

[0010] (1) A saddle-type vehicle, The saddle type vehicle includes: a load varying four-stroke engine having a crankshaft that outputs power, and having, during four strokes, a high load region in which the load that rotates the crankshaft is high, and a low load region in which the load that rotates the crankshaft is lower than the load in the high load region; a rotor having permanent magnets arranged to form a plurality of magnetic pole pairs aligned in a rotational direction and directly connected to the crankshaft, and a stator having a plurality of phase windings; an inverter having a plurality of switching units for controlling currents flowing through the respective windings of the plurality of phases; a control device that controls the plurality of switching units so as to change the plurality of switching units from a zero output state to a low output state and then to a high output state when a start command for starting the load variable four-stroke engine is input in a state in which the rotor is not rotating, the zero output state is a state in which the multiple switching units are set to make the output of the permanent magnet synchronous motor zero or substantially zero so that the rotor does not rotate; the high output state is a state in which the multiple switching units are controlled so as to accelerate rotation of the rotor, The low power state is a state in which the multiple switching units are controlled to make the output of the permanent magnet synchronous motor greater than that of the zero power state and less than that of the high power state during a period in which the rotor rotates an angle smaller than a rotation angle corresponding to one of the multiple pole pairs, so that rotation of the rotor begins, and further, the multiple switching units are controlled to continue each of the rotation of the rotor and the positive and negative patterns of current flowing in each of the multiple phase windings before and after transition to the high power state.

[0011] The saddle-type vehicle (1) includes a variable-load four-stroke engine, a permanent magnet synchronous motor, an inverter, and a control device. A variable-load four-stroke engine has a crankshaft that outputs power. A variable-load four-stroke engine has a high-load region and a low-load region during the four strokes. The high-load region is a region where the load that rotates the crankshaft is large. The low-load region is a region where the load that rotates the crankshaft is smaller than the load in the high-load region. A permanent magnet synchronous motor has a rotor and a stator. The rotor is directly connected to a crankshaft. The rotor has permanent magnets. The permanent magnets are arranged to form multiple magnetic pole pairs aligned in the direction of rotation. The stator has multiple phase windings. The inverter includes a plurality of switching units that control the current flowing through each of the windings of the multiple phases. When a start command is input while the rotor is not rotating, the control device controls the multiple switching units to change from a zero output state to a low output state and then to a high output state in that order. The start command is an instruction to start the variable load four-stroke engine. The zero output state is a state in which a number of switching units are set to make the output of the permanent magnet synchronous motor zero or substantially zero so that the rotor does not rotate. The high power state is a state in which a number of switching units are controlled so as to accelerate the rotation of the rotor. The low-power state is a state in which the multiple switching units are controlled so that the rotor starts to rotate. The multiple switching units are controlled in the low-power state during a period in which the rotor rotates an angle smaller than a rotation angle corresponding to one of the multiple pole pairs. In the low-power state, the multiple switching units are controlled to make the output of the permanent magnet synchronous motor greater than that in the zero-power state and smaller than that in the high-power state. Furthermore, the multiple switching units are controlled so that the rotation of the rotor and the positive and negative patterns of the current flowing through each of the multiple phase windings continue before and after the transition from the low-power state to the high-power state.

[0012] When a start command is input when the rotor is not rotating, the control device controls the multiple switching units to change from a zero output state to a low output state. In the low output state, a current flows through the windings so as to output a small output during a period when the stopped rotor rotates by an angle smaller than the rotation angle corresponding to one of the magnetic pole pairs. This starts the rotation of the rotor. The multiple switching units are controlled to make the output of the permanent magnet synchronous motor larger than that of the zero output state and smaller than that of the high output state. Therefore, even if the orientation of the rotor before starting to rotate is different from the ideal orientation, the difference in behavior of the rotor compared to the ideal orientation is suppressed. For example, even in a situation where a reverse rotational force is generated in the rotor, the rotational force is suppressed. Therefore, in a high output state following a low output state, when the positive and negative patterns of the current of each phase are switched sequentially while a current that increases the output is passed, the rotor is likely to follow the changing magnetic field in a short time. On the other hand, when the orientation of the rotor before starting to rotate is ideal, the rotor can receive the rotational force by immediately following the orientation of the magnetic field formed by the current of the windings in the low output state. In other words, the rotor follows the changing magnetic field from the moment it starts to rotate. Therefore, the rotor accelerates in a short time. This makes it possible to suppress delays in the time it takes to start the engine. Therefore, it is possible to shorten the time it takes to start the engine without increasing the size of the motor.

[0013] (2) (1) A saddle-type vehicle, The low output state is a state in which a plurality of switching units are controlled so that the output of the permanent magnet synchronous motor is smaller than the force with which the crankshaft overcomes the high load region of the load varying four-stroke engine.

[0014] According to the configuration of (2), in the low output state, the output of the permanent magnet synchronous motor is suppressed to a level smaller than the force with which the crankshaft overcomes the high load region. Therefore, even if the orientation of the rotor before it starts to rotate is different from the ideal orientation, the difference in the behavior of the rotor compared to the behavior in the ideal orientation is suppressed. Therefore, in the high output state following the low output state, the rotation of the rotor accelerates smoothly. Therefore, the time required for starting the engine can be shortened.

[0015] (3) A saddle-type vehicle as defined in (1) or (2), The control device PWM controls the switching unit and makes the duty ratio of the PWM control in the low output state smaller than the duty ratio in the high output state, thereby causing the permanent magnet synchronous motor to output an output smaller in the low output state than in the high output state.

[0016] According to the configuration of (3), since it is possible to output a smaller output in the low output state than in the high output state by controlling the duty ratio in the PWM control, it is possible to precisely adjust the magnitude of the output.

[0017] (4) A saddle-type vehicle as defined in any one of (1) to (3), The permanent magnet synchronous motor is a motor generator that also functions as a generator that generates electricity when driven by an engine.

[0018] According to the configuration of (4), the permanent magnet synchronous motor also functions as a generator, so that the saddle type vehicle can be made more compact and the time required for starting the engine can be shortened.

[0019] (5) A saddle-type vehicle according to any one of (1) to (4), When the start command is input, the control device causes the switching unit to start supplying current to the windings of the multiple phases so as to rotate the rotor.

[0020] According to the configuration of (5), the time from input of the start command to the start of rotation of the rotor is shortened, so that the time required for starting the engine can be further shortened.

[0021] (6) A saddle-type vehicle according to any one of (1) to (5), The variable load four-stroke engine is a single cylinder engine.

[0022] According to the configuration of (6), the rotation of the crankshaft can be accelerated in a longer run-up period before reaching the high load region, compared to a case where the engine has multiple cylinders. Therefore, the crankshaft can overcome the high load region by utilizing the large inertia force associated with the higher rotation speed, and the time required for starting can be shortened.

[0023] The terminology used herein is for the purpose of defining particular embodiments only and is not intended to limit the invention. The term "and / or" as used herein 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 the described features, steps, operations, elements, components, and / or their equivalents, 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 their equivalents are used broadly and include both direct and indirect attachments, connections, and couplings. Furthermore, "connected" and "coupled" are not limited to physical or mechanical connections or couplings, but may include direct or indirect electrical connections or couplings. Unless otherwise defined, all terms used herein (including technical and scientific terms) 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 meaning in the context of the relevant technology and this disclosure, and should not be interpreted in an ideal or overly formal sense unless expressly defined herein. In the description of the present invention, it is understood that a number of techniques and steps are disclosed. Each of these has separate benefits, and each can also be used with one or more, or in some cases all, of the other disclosed techniques. Thus, for 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 new 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 embodiments illustrated in the following drawings or description.

[0024] A saddle-type vehicle is a type of vehicle in which a driver sits astride a saddle. The saddle-type vehicle of the present invention is, for example, a motorcycle. However, the saddle-type vehicle is not limited to a motorcycle, and may be, for example, a three-wheeled motor vehicle, an ATV (All-Terrain Vehicle), or the like. In addition, it is preferable that the saddle-type vehicle is configured to be able to turn in a lean position. A saddle-type vehicle configured to be able to turn in a lean position is configured to turn in a position inclined toward the center of a curve. In this way, a saddle-type vehicle configured to be able to turn in a lean position counters the centrifugal force applied to the vehicle when turning. A saddle-type vehicle configured to be able to turn in a lean position is required to have responsiveness to operations, so miniaturization is important. However, the saddle-type vehicle is not particularly limited, and may be, for example, a vehicle that does not turn in a lean position.

[0025] The load varying four-stroke engine has a high load region and a low load region during four strokes. The load varying four-stroke engine is, for example, a single cylinder engine. The load varying four-stroke engine may be, for example, a variable combustion interval engine having two cylinders. An example of the variable combustion interval engine having two cylinders is a V-type engine. In a load-varying four-stroke engine, the fluctuation of rotation at low rotation speeds is larger than in other types of engines. The high-load region is the region in one combustion cycle of the engine where the load torque is higher than the average value of the load torque in one combustion cycle. The low-load region is the region in one combustion cycle other than the high-load region. When viewed based on the rotation angle of the crankshaft, the low-load region of an engine is, for example, wider than the high-load region. The compression stroke overlaps with the high-load region.

[0026] The permanent magnet synchronous motor is a motor having a permanent magnet. The permanent magnet synchronous motor has a stator and a rotor. The rotor of the permanent magnet synchronous motor has a permanent magnet. The stator of the permanent magnet synchronous motor has a stator core and a winding. The permanent magnet synchronous motor of the present invention has windings corresponding to multiple phases. The permanent magnet synchronous motor of the present invention may have windings corresponding to, for example, two phases or four or more phases. However, the permanent magnet synchronous motor of the present invention can easily perform sine wave driving or square wave driving by having windings corresponding to, for example, three phases. The windings of the stator are wound around the stator core. The rotor is provided so that an air gap is interposed between the permanent magnet and the stator core. The permanent magnet synchronous motor is, for example, a radial gap type motor, an outer rotor type motor having a rotor that rotates outside the stator. However, the permanent magnet synchronous motor is not particularly limited, and may be an inner rotor type motor having a rotor that rotates inside the stator. The permanent magnet synchronous motor also functions as a generator, for example. However, the permanent magnet synchronous motor is not particularly limited, and may be, for example, a permanent magnet synchronous motor that does not function as a generator. The direct connection between the rotor and the crankshaft may be, for example, a connection in which the rotor and the crankshaft have a common rotation axis. As such a connection, for example, a known connection such as a taper fit, a flange connection, or a spline connection can be adopted. The permanent magnet synchronous motor has, for example, magnetic poles that are more than 2 / 3 the number of teeth. However, the permanent magnet synchronous motor is not particularly limited, and may have, for example, magnetic poles that are 2 / 3 or less the number of teeth. The permanent magnet synchronous motor is, for example, provided so as to come into contact with oil that is shared with the crankshaft. However, the permanent magnet synchronous motor is not particularly limited, and may be provided so as not to come into contact with oil.

[0027] The inverter includes a plurality of switching units that control a current output from the battery to the permanent magnet synchronous motor. The switching units include, for example, semiconductor elements. The switching units include, for example, field effect transistors (FETs), thyristors, and insulated gate bipolar transistors (IGBTs). The inverter includes, for example, a bridge inverter that is configured with the plurality of switching units.

[0028] The control device includes, for example, a control device that controls the operation of an engine. However, the control device of the present invention is not particularly limited, and may be, for example, a control device separate from the device that controls the operation of the engine.

[0029] The start instruction is an instruction to start the engine. The start instruction is output, for example, from a start instruction unit provided in the saddle-ride type vehicle. The start instruction unit is, for example, a starter switch operated by the driver. The start instruction is output from the start instruction unit based on the driver's operation. In addition, if the saddle-ride type vehicle has an idling stop function, the control device executes the restart instruction by itself by determining predetermined engine start conditions. The engine start conditions include, for example, accelerator operation or clutch operation. The achievement of the predetermined engine start conditions is included in the input of the start instruction.

[0030] The zero output state in the control device is a state in which the multiple switching units are set so that the rotor does not rotate. In the zero output state, for example, no current is supplied from the switching units to the windings. The switching units are controlled, for example, so that the terminals of the windings are in an open state. However, the switching units are not particularly limited, and the switching units may be controlled so that the terminals of the windings are in a short-circuit state. In addition, in the zero output state, the control device may control the switching units to pass a current through the windings to the extent that the rotor does not rotate, for example for the purpose of detecting the position of the rotor. The high output state is a state in which the multiple switching units are controlled so that the rotation of the rotor accelerates. For example, the control device sequentially switches the positive and negative patterns of the current flowing through each of the multiple phase windings in the switching units so that the rotation of the rotor accelerates. The control device performs, for example, sinusoidal drive. In this case, the current flowing through each winding changes sinusoidally. Positive current and negative current are distinguished based on the average of the sinusoidally changing current. However, the drive method of the control device is not particularly limited, and may be, for example, square wave drive. The pattern is the type of positive and negative current allocation to the multiple phase windings. The low output state is a state in which the multiple switching units are controlled so that the rotor starts to rotate. The multiple switching units are controlled in the low output state during a period in which the rotor rotates an angle smaller than a rotation angle corresponding to one of the multiple magnetic pole pairs. In the low output state, the multiple switching units are controlled so that the output of the permanent magnet synchronous motor is larger than that in the zero output state and smaller than that in the high output state. For example, in the low output state, the multiple switching units are controlled so that the permanent magnet synchronous motor outputs a force smaller than the force that causes the crankshaft to exceed the high load region of the load varying four-stroke engine. The rotor continues to rotate before and after the transition from the low power state to the high power state. The rotor does not stop rotating before and after the transition from the low power state to the high power state. The rotor stops rotating means that the stopped state continues. For example, the continued rotation includes the case where the rotation speed of the rotor changes and the case where the rotation direction of the rotor changes instantaneously. The initial pattern continues across the transition from the low power state to the high power state, with the current remaining unchanged across the transition but with a change in magnitude.

[0031] The duty ratio in PWM control in a low output state and the duty ratio in PWM control in a high output state can be compared using the duty at the same phase in the period of the fluctuation when the control device periodically varies the duty, for example, as in sine wave drive. For example, in the case of a sine wave, the duty ratios at the maximum values ​​can be compared as a representative example. Effect of the Invention

[0032] According to the present invention, a saddle-type vehicle can be realized that can reduce the time required for engine start while preventing an increase in size. [Brief description of the drawings]

[0033] [Figure 1] 1 is a diagram illustrating a saddle-type vehicle according to an embodiment of the present invention; [Diagram 2] 2 is a cross-sectional view showing an engine unit in an application example of the saddle riding type vehicle 1 shown in FIG. 1. [Diagram 3] FIG. 2 is an explanatory diagram illustrating a schematic relationship between the crank angle position and the load torque of a load varying four-stroke engine. [Figure 4] 3 is a cross-sectional view showing a cross section perpendicular to the rotation axis of the permanent magnet type synchronous motor 20 shown in FIG. 2. [Diagram 5] 3 is a block diagram showing a schematic electrical configuration of the engine unit and its periphery shown in FIG. 2. [Figure 6] 3 is a flowchart illustrating an operation related to starting the load varying four-stroke engine shown in FIG. 2. [Figure 7] 7 is a time chart showing changes in current supplied to windings of multiple phases based on the control of the control device shown in FIGS. 5 and 6. [Figure 8] 8 is a time chart showing an output of a permanent magnet synchronous motor at the start of an engine according to a second embodiment. [Figure 9] 13 is a time chart showing an output of a permanent magnet synchronous motor at the start of an engine according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings.

[0035] [First embodiment] Fig. 1 is a diagram illustrating a saddle-ride type vehicle according to an embodiment of the present invention. Part (a) of Fig. 1 is a graph showing the load torque of an engine of the saddle-ride type vehicle. Part (b) of Fig. 1 is a block diagram showing a schematic configuration of the saddle-ride type vehicle. Part (c) of Fig. 1 is a cross-sectional view showing an external force configuration of a permanent magnet type synchronous motor. Part (d) of Fig. 1 is a time chart showing the output of the permanent magnet type synchronous motor at the start of the engine.

[0036] The saddle-type vehicle 1 shown in part (b) of Fig. 1 is a vehicle in which a rider sits astride a saddle 2a. The saddle-type vehicle 1 includes a body 2 and wheels 3a and 3b. The rear wheel 3b functions as a drive wheel. The saddle-type vehicle 1 includes a variable-load four-stroke engine 10, a permanent magnet synchronous motor 20, an inverter 50, and a control device 60.

[0037] The load varying four-stroke engine 10 has a crankshaft 15 that outputs power. The load varying four-stroke engine 10 outputs power to be supplied to wheels 3b, which are driving wheels, via the crankshaft 15. The wheels 3b receive the power output from the load varying four-stroke engine 10 and drive the saddle riding vehicle 1. 1, the variable load four-stroke engine 10 has a high load region TH and a low load region TL during four strokes. The high load region TH is a region where the load on the rotation of the crankshaft 15 is high. The low load region TL is a region where the load that rotates the crankshaft 15 is lower than the load in the high load region TH.

[0038] The permanent magnet synchronous motor 20 starts the variable load four-stroke engine 10 by driving the crankshaft 15 to rotate. As shown in part (c) of FIG. 1, the permanent magnet synchronous motor 20 has a rotor 30 and a stator 40. The rotor 30 is directly connected to the crankshaft 15. The rotor 30 has permanent magnets 37. The permanent magnets 37 are arranged to define a plurality of magnetic poles 37a aligned in the rotational direction. Two magnetic poles 37a adjacent to each other in the rotational direction define a magnetic pole pair 38. In other words, the permanent magnets 37 are arranged to define a plurality of magnetic pole pairs 38 aligned in the rotational direction. The stator 40 has multiple phase windings 41 . In the drawing, some of the permanent magnets 37 and magnetic poles 37a are labeled with reference numerals, and only some of the windings 41 are shown.

[0039] 1(b) again, the inverter 50 has a plurality of switching units 51. The plurality of switching units 51 controls the current flowing through each of the windings 41 of the multiple phases. The control device 60 controls the on / off states of the multiple switching units 51 to control the current flowing through each of the multiple phase windings 41. In this way, the control device 60 controls the rotation of the permanent magnet synchronous motor 20, more specifically, the rotation of the rotor 30. For example, as shown in part (d) of Fig. 1, the control device 60 switches the state of the permanent magnet synchronous motor 20 among a zero output state C0, a low output state C1, and a high output state C2. The vertical axis of the time chart in part (d) of Fig. 1 indicates the magnitude of the output of the permanent magnet synchronous motor 20. When a start command is input while the rotor 30 is not rotating, the control device 60 controls the multiple switching units 51 to change the multiple switching units 51 from the zero output state C0 to the low output state C1 and then to the high output state C2 in that order.

[0040] The zero output state C0 is a state in which the multiple switching units 51 are set to make the output of the permanent magnet synchronous motor 20 zero or substantially zero so that the rotor 30 does not rotate. More specifically, the zero output state C0 is a state in which the control device 60 controls the switching units 51 so that the rotor 30 does not rotate. For example, in the zero output state C0, all of the multiple switching units 51 are in the off state, and no current flows through any of the multiple phase windings 41. Therefore, the rotor 30 is stopped and does not rotate. The high-power state C2 is a state in which the multiple switching units 51 are controlled so that the rotation of the rotor 30 accelerates. In the high-power state C2, the control device 60 causes the multiple switching units 51 to supply current (for example, currents Iu, Iv, and Iw shown in FIG. 7) to each of the multiple-phase windings 41 so that the rotation of the rotor 30 accelerates. The high-power state C2 is a state in which the control device 60 causes the switching units 51 to supply current to each of the multiple-phase windings 41 while sequentially switching the positive / negative pattern of the current flowing through each of the multiple-phase windings 41. In the high-power state C2, the control device 60 causes the switching units 51 to sequentially switch the positive / negative pattern of the current flowing through each of the multiple-phase windings 41 from an initial pattern. The initial pattern is the initial positive / negative pattern of the current flowing through each of the multiple-phase windings 41 in the high-power state C2. The low output state C1 is a state in which the multiple switching units 51 are controlled to make the output of the permanent magnet synchronous motor 20 greater than that in the zero output state C0 and less than that in the high output state C2 so that the rotor 30 starts to rotate. The multiple switching units 51 are controlled in the low output state C1 during a period in which the rotor 30 rotates an angle smaller than the rotation angle corresponding to one of the multiple magnetic pole pairs 38. The low output state C1 is also a state in which the multiple switching units 51 are controlled so that the rotation of the rotor 30 and the positive and negative patterns of the current flowing through each of the multiple phase windings 41 continue before and after the transition to the high output state C2.

[0041] The saddle riding type vehicle 1 is provided with a start instruction unit 4. The start instruction unit 4 outputs a start instruction for starting the load variable four-stroke engine 10 in response to, for example, an operation by the driver. When a start command is input while the rotor 30 is not rotating, the control device 60 causes the switching unit 51 to pass current through the multiple phase windings 41 so as to rotate the permanent magnet synchronous motor 20 through a low output state C1 and a high output state C2.

[0042] For example, before a start command is input at time t0 in the time chart of part (d) of Fig. 1, the rotor 30 is not rotating and is stopped. The control device 60 controls the switching unit 51 to the zero output state C0. Note that the control device 60 does not have to constantly control the switching unit 51 to the zero output state C0 before the start command is input. For example, it is sufficient for the control device 60 to control the switching unit 51 to the zero output state C0 at the time the start command is input. When a start command is input at time t0, the control device 60 causes the switching unit 51 to pass current through the multiple phase windings 41 so that the permanent magnet synchronous motor 20 enters the low output state C1. In the low power state C1, the control device 60 controls the switching unit 51 to continue the rotation of the rotor 30 and the initial pattern before and after the transition to the high power state C2. A pattern is a combination of positive and negative current assignments to the windings 41 of multiple phases. For example, in a configuration in which each of the windings 41 of multiple phases belongs to one of the u-phase, v-phase, and w-phase, the current direction in the u-phase, the current direction in the v-phase, and the current direction in the w-phase form one pattern. For example, when a start command is input at time t0, the control device 60 controls the switching unit 51 to pass currents in the direction of the combination of "Pattern 1" as the initial pattern through the windings 41 belonging to the u-phase, v-phase, and w-phase. For example, during the low output state C1, the initial pattern does not change to "Pattern 1." In the low output state C1, the control device 60 continues the initial pattern. During the low output state C1, the directions of the currents in the windings 41 belonging to the u-phase, v-phase, and w-phase do not change, but the magnitudes of the currents in the respective windings 41 change. However, it is also possible for the magnitude of the current in winding 41 not to change during low power state C1, or for the pattern to change during low power state C1, eventually converging to an initial pattern in low power state C1.

[0043] 1 is a period during which the rotor 30 rotates by a rotation angle corresponding to one of the multiple magnetic pole pairs 38. The period of the low output state C1 is shorter than the period PA. The control device 60 maintains the low output state C1 for a period shorter than the period PA during which the rotor 30 rotates through a rotation angle corresponding to one of the multiple magnetic pole pairs . In the low output state C1, the multiple switching units 51 are controlled to make the output of the permanent magnet synchronous motor 20 greater than in the zero output state C0 and smaller than in the high output state C2.

[0044] After the low power state C1, control of the controller 60 transitions to a high power state C2. In the high-output state C2, the control device 60 sequentially switches the positive / negative pattern of the current flowing through each of the multiple-phase windings 41 in the switching unit 51. The control device 60 switches the pattern from the initial pattern. However, the control device 60 continues the initial pattern for a certain period even after transitioning to the high-output state C2. In other words, the multiple switching units 51 are controlled so that the pattern continues before and after the transition from the low-output state C1 to the high-output state C2. The rotor 30 does not stop before and after the transition from the low-output state C1 to the high-output state C2. In other words, the rotation of the rotor 30 is maintained. For example, when "Pattern 1" is adopted as the initial pattern in the low output state C1 as shown in part (d) of FIG. 1, the control device 60 continues to maintain the initial pattern "Pattern 1" in the high output state C2. Thereafter, at time t2, the control device 60 sequentially switches the positive / negative current pattern from "Pattern 1" to "Pattern 2", then to "Pattern 3", .... As the cycle of the change in the positive / negative current pattern gradually becomes shorter, the rotation of the crankshaft 15 connected to the rotor 30 accelerates. The crankshaft 15 rotates, overcoming the reaction force of the high load region TH. After that, the variable load four-stroke engine 10 starts.

[0045] By the control of the control device 60 described above, first, in the low output state C1, a current flows through the winding 41 so as to output a small output during a period in which the stopped rotor 30 rotates an angle smaller than the rotation angle corresponding to one of the magnetic pole pairs 38. This suppresses the fluctuation of the rotation of the rotor 30 even if the orientation of the stopped rotor 30 is different from the ideal orientation. For example, even in a situation in which a reverse rotational force is generated in the rotor 30, the rotational force is suppressed. Therefore, in the high output state C2 following the low output state C1, when the positive and negative currents of the phases are switched sequentially while a current that increases the output is passed, the rotor 30 is likely to follow the magnetic field formed in the high output state C2. That is, the rotation of the rotor 30 accelerates smoothly from the start. On the other hand, when the orientation of the rotor 30 is the ideal orientation in the zero output state C0, the rotor 30 can receive the rotational force by immediately following the orientation of the magnetic field formed by the current in the low output state C1. That is, the rotor 30 continues to accelerate more smoothly from the start of rotation. This suppresses the delay in the time required for starting the engine. Therefore, the time required for starting the engine can be shortened without increasing the size of the permanent magnet synchronous motor 20.

[0046] [Example of application] Fig. 2 is a cross-sectional view showing an engine unit in an application example of the saddle riding type vehicle 1 shown in Fig. 1. In the application example shown in Fig. 2, elements common to those in Fig. 1 are denoted by the same reference numerals and will not be described below. This application example can be applied to both the second embodiment and the third embodiment described later.

[0047] 2 includes a variable load four-stroke engine 10 and a permanent magnet synchronous motor 20. The engine unit EU also includes a clutch 18 and a transmission 19.

[0048] The variable load four-stroke engine 10 shown in FIG. 2 is a single-cylinder engine.

[0049] The variable load four-stroke engine 10 includes a crankcase 11, a cylinder 12, a piston 13, a connecting rod 14, and a crankshaft 15. The piston 13 is provided in the cylinder 12 so as to be able to reciprocate. The crankshaft 15 is rotatably provided within the crankcase 11. The crankshaft 15 is connected to the piston 13 via a connecting rod 14. A cylinder head 16 is attached to the upper part of the cylinder 12. The cylinder 12, the cylinder head 16, and the piston 13 form a combustion chamber. The crankcase 11 and the cylinder 12 are configured so that their interiors are lubricated with oil. The cylinder head 16 is provided with an exhaust valve and an intake valve, not shown. The variable load four-stroke engine 10 is also provided with a spark plug 17, a fuel injector J (see FIG. 5, for example), and a throttle valve (not shown). The throttle valve adjusts the amount of air supplied into the cylinder 12 according to its opening. The fuel injector J supplies fuel to the combustion chamber in the cylinder 12. A mixture of air passing through the throttle valve and fuel injected from the fuel injector J is supplied to the combustion chamber in the cylinder 12. The intake valve controls the supply of the mixture to the combustion chamber in the cylinder 12. The spark plug 17 ignites the mixture in the cylinder 12, causing the mixture to burn.

[0050] A permanent magnet synchronous motor 20 is attached to one end 15a of the crankshaft 15. For example, the permanent magnet synchronous motor 20 shown in Fig. 2 is disposed in the crankcase 11 together with the crankshaft 15. The permanent magnet synchronous motor 20 is provided so as to come into contact with engine oil.

[0051] The load varying four-stroke engine 10 outputs rotational force by a combustion action of burning an air-fuel mixture. In detail, a piston 13 moves by the combustion of an air-fuel mixture containing fuel supplied to a combustion chamber. The piston 13 reciprocates by the combustion of the air-fuel mixture. A crankshaft 15 rotates in conjunction with the reciprocating motion of the piston 13. The rotational force, i.e., power, is output to the outside of the load varying four-stroke engine 10 via the crankshaft 15. In the example shown in FIG. 2, the power of the crankshaft 15 is transmitted to the wheels 3b (see FIG. 1) via a clutch 18 and a transmission 19. The saddle riding type vehicle 1 is driven by the wheels 3b (see FIG. 1) which receive power from the load varying four-stroke engine 10 via the crankshaft 15.

[0052] 3 is an explanatory diagram showing a schematic diagram of the relationship between the crank angle position and the load torque of the load variable four-stroke engine 10. The load torque is the torque required to rotate the crankshaft 15 when the load variable four-stroke engine 10 is not performing a combustion operation.

[0053] The variable load four-stroke engine 10 has a high load region TH and a low load region TL within a combustion cycle that corresponds to four strokes in a combustion operation. The high load range TH is a range in which the load torque is higher than the average load torque Av in one combustion cycle of the variable load four-stroke engine 10. When viewed based on the rotation angle of the crankshaft 15, the low load range TL is wider than the high load range TH. More specifically, the low load range TL is wider than the high load range TH. In other words, the rotation angle range corresponding to the low load range TL is wider than the rotation angle range corresponding to the high load range TH. The variable load four-stroke engine 10 rotates while repeating a combustion stroke (expansion stroke), exhaust stroke, intake stroke, and compression stroke. The compression stroke overlaps with the high load range TH.

[0054] One combustion cycle of the load varying four-stroke engine 10 includes one combustion stroke, one exhaust stroke, one intake stroke, and one compression stroke. During the intake stroke, the air-fuel mixture is supplied to the combustion chamber. During the compression stroke, the piston 13 compresses the air-fuel mixture in the combustion chamber. During the expansion stroke, the air-fuel mixture is ignited by the spark plug 17 and burns, pushing the piston 13. During the exhaust stroke, the exhaust gas after combustion is discharged from the combustion chamber. The high load torque in the high load range TH is mainly due to the reaction force of the compression of the air-fuel mixture.

[0055] FIG. 4 is a cross-sectional view showing a cross section perpendicular to the rotation axis of the permanent magnet synchronous motor 20 shown in FIG. 2 and 4 also has a function of generating electricity when driven by, for example, the variable load four-stroke engine 10 during combustion operation. In other words, the permanent magnet synchronous motor 20 combines the functions of a starting motor that starts the variable load four-stroke engine 10 and a generator that generates electricity when driven by the variable load four-stroke engine 10. The permanent magnet synchronous motor 20 is a motor generator.

[0056] The permanent magnet synchronous motor 20 is a three-phase brushless motor. The permanent magnet type synchronous motor 20 has a rotor 30 and a stator 40. The permanent magnet type synchronous motor 20 is an outer rotor type. That is, the rotor 30 is an outer rotor, and the stator 40 is an inner stator.

[0057] The rotor 30 has a rotor body 31. The rotor body 31 is a bottomed, cylindrical member made of, for example, a ferromagnetic material. The rotor body 31 is directly connected to the crankshaft 15. As a result, the rotor 30 is directly connected to the crankshaft 15 of the variable load four-stroke engine 10. In other words, the rotor 30 and the crankshaft 15 have a common rotation axis. The rotor 30 is not provided with any windings to which current is supplied. The rotor 30 has a permanent magnet 37. The rotor 30 has a plurality of magnetic poles 37a. The plurality of magnetic poles 37a are formed by the permanent magnets 37. The plurality of magnetic poles 37a are provided on the inner circumferential surface of the back yoke portion 34. The plurality of magnetic poles 37a are provided on the outer side of the stator 40 in the radial direction of the permanent magnet type synchronous motor 20. The rotor 30 shown in FIG. 4 has a plurality of permanent magnets 37. For example, a plurality of magnetic poles 37a are provided on each of the plurality of permanent magnets 37. However, the permanent magnet 37 may also be configured to be formed by, for example, a single annular magnet. In this case, the single annular magnet is magnetized so that the plurality of magnetic poles 37a are aligned on the inner circumferential surface. Also, the permanent magnet 37 may be configured by arc-shaped magnet blocks the number of which is less than the plurality of magnetic poles 37a.

[0058] The multiple magnetic poles 37a are provided such that N poles and S poles are alternately arranged in the circumferential direction of the permanent magnet synchronous motor 20. Two adjacent magnetic poles 37a constitute a magnetic pole pair 38. The permanent magnet synchronous motor 20 has multiple magnetic pole pairs 38. The rotation angle corresponding to one of the magnetic pole pairs 38 is the base angle R. 4, the rotor 30 has 24 magnetic poles. The number of magnetic poles of the rotor 30 refers to the number of magnetic poles 37a facing the stator 40. No magnetic material is provided between the magnetic poles 37a and the stator 40. For example, a non-magnetic cover may be provided between the magnetic poles 37a and the stator 40.

[0059] The stator 40 has a plurality of windings 41 and a stator core 42. The stator core 42 has a plurality of teeth 43 spaced apart in the circumferential direction. The teeth 43 extend radially outward from the stator core 42. In the example of FIG. 4, a total of 18 teeth 43 are spaced apart in the circumferential direction. In other words, the stator core 42 has a total of 18 slots SL spaced apart in the circumferential direction. The teeth 43 are arranged at equal intervals in the circumferential direction.

[0060] The permanent magnet synchronous motor 20 has magnetic poles 37a that are more than ⅔ the number of teeth 43. In this case, the windings 41 have a larger inductance than, for example, a case in which the windings 41 have magnetic poles 37a that are ⅔ or less the number of teeth 43. This suppresses the temperature rise of the permanent magnet synchronous motor 20 during power generation.

[0061] A winding 41 is wound around each tooth portion 43. That is, the windings 41 of multiple phases are provided to pass through the slots SL. FIG. 4 shows a state in which the windings 41 are in the slots SL. Each of the windings 41 of multiple phases belongs to one of the U phase, V phase, and W phase. The windings 41 are arranged, for example, in the order of the U phase, V phase, and W phase.

[0062] The rotor 30 rotates when a periodically changing current is supplied to the windings 41. For example, the rotor 30 rotates when a periodically changing sinusoidal current or a rectangular wave current flows through the windings 41. The rotor 30 rotates a basic angle R in response to one period (360 degrees) of the change in the current flowing through the windings 41. The basic angle R is also referred to as 360 degrees in electrical angle.

[0063] FIG. 5 is a block diagram showing a schematic electrical configuration of the engine unit and its periphery shown in FIG.

[0064] The control device 60 provided in the saddle riding type vehicle 1 controls each part of the saddle riding type vehicle 1 including the inverter 50 . The inverter 50 is connected to the permanent magnet synchronous motor 20 and the battery 5. When the permanent magnet synchronous motor 20 operates as a motor, the battery 5 supplies power to the permanent magnet synchronous motor 20. The battery 5 is charged by the power generated by the permanent magnet synchronous motor 20.

[0065] The inverter 50 includes a plurality of switching units 51. The switching units 51 shown in FIG. 5 constitute a three-phase bridge inverter. The plurality of switching units 51 are connected to each phase of the windings 41 of multiple phases. More specifically, of the plurality of switching units 51, two switching units 51 connected in series constitute a half bridge. The half bridge of each phase is connected in parallel to the battery 5. The switching units 51 constituting the half bridge of each phase are connected to each phase of the windings 41 of multiple phases.

[0066] The switching unit 51 controls the current flowing between the battery 5 and the permanent magnet synchronous motor 20. In detail, the switching unit 51 switches between passing / cutting off the current between the battery 5 and the multi-phase windings 41. In detail, the on / off operation of the switching unit 51 switches between energizing and deenergizing the windings 41 of the multiple phases. Furthermore, when the permanent magnet synchronous motor 20 functions as a generator, the on / off operation of the switching unit 51 switches between passing / cutting off current between each of the windings 41 and the battery 5. The switching unit 51 is sequentially switched on and off to control the rectification and voltage of the three-phase AC output from the permanent magnet synchronous motor 20. The switching unit 51 controls the current output from the permanent magnet synchronous motor 20 to the battery 5.

[0067] [About the drive system] The control device 60 performs pulse width modulation (PWM) control on the switching unit 51. In this way, the control device 60 controls the current flowing through the winding 41. For example, the control device 60 controls the switching unit 51 to perform sine wave driving on the winding 41 . In sinusoidal wave driving, the control device 60 turns on and off a plurality of switching units 51 so that a sinusoidal current flows through each winding 41 of the permanent magnet synchronous motor 20. The control device 60 causes a sinusoidal current to flow through each winding 41 by dynamically changing the duty ratio of the switching unit 51 corresponding to each stator winding W. The control device 60 causes a sinusoidal current to flow through the stator winding W by turning on and off the switching units 51 in a period shorter than one period of an electrical angle. The current flowing through the windings 41 of the three phases sequentially becomes maximum and minimum, like a waveform in a three-phase alternating current. A current always flows through one of the windings 41. For example, in the high power state C2, the control device 60 changes the duty ratio of the switching unit 51 from approximately 0% to approximately 100% depending on the height of the sine wave within one period of the sine wave. In response to this, the control device 60 makes the duty ratio of the PWM control in the low power state C1 smaller than the duty ratio in the high power state C2, thereby causing the permanent magnet synchronous motor 20 to output a smaller output in the low power state C1 than in the high power state C2. For example, the control device 60 controls the switching unit 51 so that the output of the permanent magnet synchronous motor 20 in the low output state C1 is smaller than the force with which the crankshaft 15 overcomes the high load region of the variable load four-stroke engine 10. More specifically, in the low power state C1, the control device 60 changes the duty ratio of the switching unit 51 in accordance with the height of the sine wave within one cycle of the sine wave, for example, within a range of about 30% with 50% as the center, that is, within a range of about 35% to about 65%. In this case, the current flowing through each winding 41 in the low power state C1 is 1 / 3 of the current in the high power state C2. As a result, the output of the permanent magnet synchronous motor 20 in the low power state C1 is 1 / 3 of the output of the permanent magnet synchronous motor 20 in the high power state C2. Sine wave driving reduces the output of current components that do not contribute to the generation of rotational force, resulting in high power utilization efficiency.

[0068] As a control of the current waveform, the control device 60 may control the switching unit 51 so as to drive the winding 41 with a square wave, for example. For example, when controlling windings 41 to pass a square wave current, control device 60 turns on and off multiple switching units 51 at timing according to the 120-degree conduction method. The 120-degree conduction method is a method in which a current suspension period is provided for each phase of multiple-phase windings 41, and intermittent current is performed with a current angle of less than 180 degrees. However, with the 120-degree conduction method, a current equivalent to a maximum value always flows through one of windings 41. For example, in the high power state C2, the control device 60 maintains the duty ratio of the switching unit 51 at approximately 100% during the current supply period within one cycle of the square wave. In contrast, in the low power state C1, the control device 60 maintains the duty ratio of the switching unit 51 at approximately 30% during the current supply period within one cycle of the square wave. In this case, the current flowing through each winding 41 in the low power state C1 is 1 / 3 of the current in the high power state C2. As a result, the output of the permanent magnet synchronous motor 20 in the low power state C1 is 1 / 3 of the output of the permanent magnet synchronous motor 20 in the high power state C2. Sine wave driving simplifies control. This allows the use of a computing device with lower processing power. Reason High degree.

[0069] Each of the switching units 51 has a switching element. The switching units 51 are, for example, transistors, and more specifically, FETs (Field Effect Transistors).

[0070] The control device 60 is connected to a fuel injector J, an ignition plug 17, and a battery 5. A rotor position detector 70 is also connected to the control device 60. The control device 60 obtains the rotational position and rotational speed of the crankshaft 15 based on the detection result of the rotor position detector 70.

[0071] The control device 60 controls the operation of the permanent magnet synchronous motor 20 by controlling the on / off operation of each of the switching units 51. The starting and power generation control unit 62 includes a start control unit 621 and a power generation control unit 622. The combustion control unit 63 controls the ignition plug 17 and the fuel injector J, thereby controlling the combustion operation of the variable load four-stroke engine 10.

[0072] The control device 60 is composed of a computer having a central processing unit 60a and a storage device 60b. The central processing unit 60a performs calculations based on a control program. The storage device 60b stores data related to the program and calculations. The control of the control device 60 is realized by the computer having the central processing unit 60a and the storage device 60b and the control program executed by the computer. The portion that controls the fuel injection device J and the spark plug 17 may be configured at a location separate from the control device 60 that controls the switching unit 51 as separate devices, or may be configured integrally.

[0073] FIG. 6 is a flowchart illustrating the operation related to starting the load varying four-stroke engine shown in FIG.

[0074] First, when the variable-load four-stroke engine 10 is stopped, the control device 60 controls the permanent magnet synchronous motor 20 to a zero output state C0 (S11). The rotor 30 is stopped. That is, the crankshaft 15 is stopped.

[0075] When the start command is input (Yes in S12), the control device 60 causes the switching unit 51 to start supplying current to the multiple phase windings 41 so that the permanent magnet synchronous motor 20 starts rotating in the low output state C1. The control device 60 controls the switching unit 51 in the low output state C1 during the low output period. The control device 60 controls the switching unit 51 so that current flows to the U-phase, V-phase, and W-phase windings 41 in the direction of "Pattern 1" (see FIG. 1), for example. The low power period C1 is a period during which the rotor 30 rotates an angle smaller than the rotation angle corresponding to one of the multiple magnetic pole pairs 38. The low power period C1 is a period set based on, for example, the operating characteristics of the load varying four-stroke engine 10 and the permanent magnet synchronous motor 20. Note that the low power period C1 may be set, for example, by detecting that the rotor 30 actually rotates an angle smaller than the rotation angle corresponding to one of the magnetic pole pairs 38.

[0076] When the low output period C1 ends (No in S14), the control device 60 causes the switching unit 51 to supply current to the multiple phase windings 41 so that the permanent magnet synchronous motor 20 accelerates rotation in the high output state C2. In the high output state C2, the control device 60 maintains "Pattern 1" (see FIG. 1) as the direction in which current flows to the U-phase, V-phase, and W-phase windings 41, and then switches the pattern. In the high output state C2, the control device 60 controls the switching unit 51 so that the permanent magnet synchronous motor 20 outputs a larger output than in the low output state C1.

[0077] When the rotation speed of the crankshaft 15 reaches a startup rotation speed suitable for the combustion operation in the load varying four-stroke engine 10 (Yes in S16), the control device 60 ends the control in the high output state C2. As a result, the control device 60 stops the output of power from the permanent magnet synchronous motor 20.

[0078] Fig. 7 is a time chart showing changes in currents supplied to the windings 41 of multiple phases based on the control of the control device shown in Fig. 5 and Fig. 6. The chart in Fig. 7 shows the currents Iu, Iv, and Iw of the U-phase, V-phase, and W-phase windings 41, respectively, when sine wave driving is adopted. The chart in Fig. 7 also shows the control states of the permanent magnet synchronous motor 20 and the magnitude of the output corresponding to the states. The chart in Fig. 7 also shows the transition of combination patterns of the currents Iu, Iv, and Iw of the U-phase, V-phase, and W-phase windings 41, respectively.

[0079] Before a start command is input at time t0, the control device 60 controls the switching unit 51 to the zero output state C0. The rotor 30 does not rotate and is at a standstill. The permanent magnet synchronous motor 20 does not output power.

[0080] When a start command is input at time t0, the control device 60 causes the switching unit 51 to pass current through the multiple phase windings 41 so that the permanent magnet synchronous motor 20 enters the low output state C1. The control device 60 controls the switching unit 51, for example, to perform sine wave driving on the windings 41. However, in the low output state C1, the range in which the duty ratio changes to pass a sine wave current is limited to 30% of that in the high output state C2. As a result, the output of the permanent magnet synchronous motor 20 in the low power state C1 is smaller than the output in the high power state C2. For example, the output of the permanent magnet synchronous motor 20 in the low power state C1 is 30% of the output in the high power state C2. 7, in the low output state C1, the direction of current Iu in the U-phase winding 41 is positive. The direction of current Iv in the V-phase winding 41 is negative. The direction of current Iw in the W-phase winding 41 is negative. This combination of current directions is referred to as "Pattern 1." The control device 60 maintains the low output state C1 during the low output period from time t0 to t1, which is shorter than one period PA of the electrical angle. The control device 60 maintains "Pattern 1" during the low output period from time t0 to t1. The control device 60 controls the switching unit 51 so that the permanent magnet synchronous motor 20 outputs a small output in the low output state C1 during the period when the rotor 30 rotates at an angle smaller than the basic angle R (see FIG. 4) corresponding to one of the magnetic pole pairs 38. Therefore, when a start command is input, the rotor 30, which was stopped, starts to rotate as a current flows through the windings 41. Because a current flows through the windings 41 in the low output state C1, the rotor 30 starts to rotate with a relatively weak rotational force and a low speed. The rotation angle of the rotor 30 in the low output state C1 is smaller than the base angle R (see FIG. 4).

[0081] When time t1 has elapsed, the control device 60 causes the switching unit 51 to pass current through the multiple phase windings 41 so that the permanent magnet synchronous motor 20 enters the high output state C2. Controller 60 causes current to flow through winding 41 by varying the duty ratio without any restriction on the duty ratio as in low power state C1. In the high-power state C2, the control device 60 first maintains "Pattern 1." In the high-power state C2, the control device 60 sets "Pattern 1" as the initial state, and switches the current direction pattern in the order of "Pattern 2," "Pattern 3," and "Pattern 4." The switching of the combination of current directions is performed in accordance with the sinusoidal change in current. The output of the permanent magnet synchronous motor 20 in the high output state C2 is smaller than the output in the low output state C1. In the high output state C2, the rotation of the rotor 30 accelerates. That is, the rotation of the crankshaft 15 accelerates.

[0082] 7, when the rotation speed of the crankshaft 15 reaches a starting rotation speed suitable for the combustion operation in the variable load four-stroke engine 10 (Yes in S16), the control device 60 ends the control in the high output state C2. This causes the output of power from the permanent magnet synchronous motor 20 to stop. Also, the combustion operation in the variable load four-stroke engine 10 starts.

[0083] According to the control of the control device 60 described above, first, in the low output state C1, a current flows through the windings 41 so as to output a small output during a low output period in which the stopped rotor 30 rotates at an angle smaller than the base angle R (see FIG. 4). This suppresses the fluctuation of the rotation of the rotor 30 even if the orientation of the stopped rotor 30 is different from the ideal orientation. Therefore, in the high output state C2 following the low output state C1, when the direction of the current of each phase is switched sequentially while a current that increases the output flows, the rotor 30 is likely to follow the magnetic field formed in the high output state C2. Therefore, the time required for engine start can be shortened without increasing the size of the permanent magnet synchronous motor 20.

[0084] [Second embodiment] FIG. 8 is a time chart showing the output of the permanent magnet synchronous motor at the start of the engine according to the second embodiment.

[0085] The control device 60 in this embodiment controls the switching unit 51 in such a way that the power output from the permanent magnet synchronous motor 20 gradually increases in the low output state C1.

[0086] [Third embodiment] FIG. 9 is a time chart showing the output of the permanent magnet synchronous motor at the start of the engine according to the third embodiment.

[0087] The control device 60 in this embodiment controls the switching unit 51 in the low output state C1 so that the power output from the permanent magnet synchronous motor 20 gradually increases from zero. [Explanation of symbols]

[0088] 1: Saddle-type vehicle 10: Load-varying four-stroke engine 15: Crankshaft 20: Permanent magnet synchronous motor 30: Rotor 37: Permanent magnet 37a:Magnetic pole 38: Magnetic pole pair 40: Stator 41: Winding 50: Inverter 51: Switching section 60: Control device C0: Zero output state C1: Low power state C2: High output state

Claims

1. A saddle-type vehicle, The saddle type vehicle includes: a load varying four-stroke engine having a crankshaft that outputs power, and having, during four strokes, a high load region in which the load that rotates the crankshaft is large, and a low load region in which the load that rotates the crankshaft is smaller than the load in the high load region; a rotor having permanent magnets arranged to form a plurality of magnetic pole pairs aligned in a rotational direction and directly connected to the crankshaft, and a stator having a plurality of phase windings; an inverter having a plurality of switching units for controlling currents flowing through the respective windings of the plurality of phases; a control device that controls the plurality of switching units so as to change the plurality of switching units from a zero output state to a low output state and then to a high output state when a start command for starting the load varying four-stroke engine is input in a state in which the rotor is not rotating, the zero output state is a state in which the multiple switching units are set to make the output of the permanent magnet synchronous motor zero or substantially zero so that the rotor does not rotate; the high output state is a state in which the multiple switching units are controlled so as to accelerate rotation of the rotor, The low power state is a state in which the multiple switching units are controlled to make the output of the permanent magnet synchronous motor greater than that of the zero power state and less than that of the high power state during a period in which the rotor rotates an angle smaller than a rotation angle corresponding to one of the multiple pole pairs, so that rotation of the rotor begins, and further, the multiple switching units are controlled to continue each of the rotation of the rotor and the positive and negative patterns of current flowing in each of the multiple phase windings before and after the transition to the high power state.

2. 2. The saddle-type vehicle according to claim 1, The low output state is a state in which a plurality of switching units are controlled so that the output of the permanent magnet synchronous motor is smaller than the force with which the crankshaft overcomes the high load region of the load varying four-stroke engine.

3. 3. The saddle-type vehicle according to claim 1 or 2, The control device PWM controls the switching unit and makes the duty ratio of the PWM control in the low output state smaller than the duty ratio in the high output state, thereby causing the permanent magnet synchronous motor to output an output smaller in the low output state than in the high output state.

4. A saddle-type vehicle according to any one of claims 1 to 3, The permanent magnet synchronous motor is a motor generator that also functions as a generator that generates electricity when driven by an engine.

5. A saddle-type vehicle according to any one of claims 1 to 4, When the start command is input, the control device causes the switching unit to start supplying current to the windings of the multiple phases so as to rotate the rotor.

6. A saddle-type vehicle according to any one of claims 1 to 5, The variable load four-stroke engine is a single cylinder engine.

Images