Regenerative control method and saddle-riding vehicle

Abstract

To bring a braking feeling felt by a user upon execution of regenerative control close to a feeling intended by the user.SOLUTION: A regenerative control method for a vehicle according to an embodiment is executed in a processing circuit of a vehicle including an electric motor as a drive source, and includes: determining whether a start condition for regenerative control for requiring the electric motor to generate regenerative torque is satisfied; acquiring a degree of decrease in an accelerator operation amount with passage of time before starting the regenerative control; and determining required regenerative torque which is the regenerative torque required of the electric motor, on the basis of the degree of decrease in the accelerator operation amount.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a regenerative control method and a saddle-ride vehicle. [Background technology]

[0002] Patent Document 1 discloses a regenerative braking device for an electric vehicle that determines a deceleration state from a motor rotation speed and an accelerator signal, and performs regenerative braking according to the deceleration state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-64304 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for the braking feeling that a user feels when regenerative control is executed in an electric vehicle to be closer to the feeling that the user intends.

[0005] Therefore, an object of one aspect of the present disclosure is to provide a regenerative control method and a saddle riding vehicle that can bring the braking feeling felt by the user when regenerative control is executed closer to the feeling intended by the user. [Means for solving the problem]

[0006] A regenerative control method for a vehicle according to one embodiment of the present disclosure is a regenerative control method executed in a processing circuit of a vehicle having an electric motor as a drive source, and includes determining whether a start condition for regenerative control requesting the electric motor to generate regenerative torque is satisfied, obtaining a degree of decrease in accelerator operation amount over time prior to the start of the regenerative control, and determining a required regenerative torque, which is the regenerative torque requested of the electric motor, based on the degree of decrease in the accelerator operation amount.

[0007] A regenerative control method for a vehicle according to another aspect of the present disclosure is a regenerative control method executed in a processing circuit of a vehicle having an electric motor as a drive source, and includes determining whether a start condition for regenerative control requesting the electric motor to generate regenerative torque is satisfied, and determining a required regenerative torque, which is the regenerative torque requested of the electric motor, after it is determined that the start condition is satisfied, wherein the absolute value of the required regenerative torque determined within a predetermined period from the start of the regenerative control is greater than the absolute value of the required regenerative torque determined after the predetermined period has elapsed.

[0008] A saddle-riding vehicle according to one embodiment of the present disclosure includes an accelerator operator operated by a user, drive wheels, an electric motor as a drive source for driving the drive wheels, and a processing circuit for controlling the regenerative torque of the electric motor for braking the drive wheels, and the processing circuit is configured to determine whether a start condition for regenerative control requesting the electric motor to generate regenerative torque is satisfied, obtain the degree of reduction in accelerator operation amount over time prior to the start of the regenerative control, and determine a required regenerative torque, which is the regenerative torque requested of the electric motor, based on the degree of reduction in accelerator operation amount. Effect of the Invention

[0009] According to the present disclosure, the braking feeling that the user feels when regenerative control is executed can be made closer to the feeling that the user intends. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of a vehicle according to one embodiment. [Diagram 2] FIG. 2 is a block diagram showing the electrical configuration of the vehicle shown in FIG. [Diagram 3] 4 is a graph showing an example of a normal torque map and a strong regenerative torque map. [Figure 4] 4 is a flowchart showing a flow of vehicle travel control by a controller. [Diagram 5] 4 is a flowchart showing a flow of regenerative control. [Figure 6] 11 is a graph for explaining an example of a method for calculating a degree of decrease. [Figure 7] 13 is a graph showing changes in coefficients over time. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment will be described with reference to the drawings.

[0012] (Vehicle configuration) FIG. 1 is a schematic diagram of a vehicle 1 according to an embodiment. In this embodiment, the vehicle 1 is a saddle-type electric two-wheeler. The vehicle 1 includes a vehicle body 2 and a battery pack 3. The battery pack 3 is detachable from the vehicle body 2. The vehicle body 2 is supported by front wheels 4, which are driven wheels, and rear wheels 5, which are driving wheels. An electric motor 6, which is a driving source, is supported by the vehicle body 2. The electric motor 6 generates a driving force for driving the vehicle, which is transmitted to the rear wheels 5, which are driving wheels. The driving torque generated by the electric motor 6 is transmitted to the rear wheels 5 via a power transmission mechanism 7. The electric motor 6 can rotate forward and backward. The electric motor 6 functions as a driving source for driving the vehicle. In addition, a rotation speed sensor 22 (see FIG. 2) that detects the rotation speed of the output shaft of the electric motor 6 is disposed in the electric motor 6. The electric motor 6 also functions as a generator that generates electricity using the power transmitted from the driving wheels when the vehicle 1 is decelerating. The power transmission mechanism 7 includes a reducer 7a that reduces the rotation of the electric motor 6, and a mechanism 7b (e.g., a chain transmission mechanism or a belt transmission mechanism) that transmits the rotational power output from the reducer 7a to the axle of the rear wheel 5.

[0013] The vehicle body 2 has a vehicle body frame, which has a head pipe 11 and a pair of left and right main frames 12 extending rearward from the head pipe 11. The head pipe 11 rotatably supports a steering shaft 13. A front fork 14 extending substantially in the vertical direction is connected to the steering shaft 13, and a front wheel 4 is rotatably supported at a lower end of the front fork 14. A bar-shaped handle 15 extending left and right is connected to the upper end of the steering shaft 13. An accelerator operator 15a for adjusting the drive torque generated by the electric motor 6 is disposed on the handle 15. In this embodiment, the accelerator operator 15a is an accelerator grip, which is the right grip of the handle 15.

[0014] When the accelerator operator 15a is rotated from a reference position in a predetermined first moving direction, the amount of operation (hereinafter, accelerator operation amount) is detected by the accelerator sensor 21 (see FIG. 2). The accelerator sensor 21 is realized, for example, by a position sensor that detects the amount of rotation of a grip. For example, the accelerator sensor 21 may be realized by a magnetic field detection sensor using a Hall IC. When no operation is given by the user who is the driver, the accelerator operator 15a is given a biasing force so as to return to the reference position. In this embodiment, the predetermined first moving direction is set to be counterclockwise when viewed from the right side of the vehicle body. The output of the electric motor 6 increases as the amount of movement in the first moving direction increases relative to the reference position, in other words, as the amount of acceleration operation increases.

[0015] A meter device 8 is disposed in front of the handlebar 15. The meter device 8 displays the traveling speed, motor RPM, remaining battery charge, etc. The meter device 8 is supported on the head pipe 11 via a bracket 16.

[0016] The battery pack 3 is housed in a battery case 17. The battery case 17 is disposed between a pair of main frames 12 in the left-right direction and is fixed to the pair of main frames 12. The battery pack 3 has a chargeable and dischargeable battery 3a, a battery management unit, etc. When housed in the battery case 17, the battery 3a, the battery management unit, etc. of the battery pack 3 are electrically connected to electronic devices on the vehicle body 2 side.

[0017] (Electrical configuration) 2 is a block diagram showing the electrical configuration of the vehicle 1 in FIG. 1. A controller 31 and an inverter 32 are fixed to the body 2 of the vehicle 1. In terms of hardware, the controller 31 has a processor, a memory, an I / O interface, and the like. The memory includes, for example, a storage such as a hard disk or a flash memory, and a main memory such as a RAM. A program for issuing a control command to the electric motor 6 is stored in the storage. The processor and the memory of the controller 31 are examples of a processing circuit.

[0018] The controller 31 receives an accelerator operation amount detected by the accelerator sensor 21. In this specification, the accelerator operation amount may also be referred to as an accelerator opening degree. The controller 31 also receives a motor rotation speed detected by the rotation speed sensor 22. The controller 31 and the inverter 32 are connected to each other so as to be able to communicate with each other via a CAN (Controller Area Network) 30. The battery 3a is also connected to the electric motor 6 via the inverter 32.

[0019] When the vehicle 1 is traveling, the controller 31 executes powering control or regenerative control based on the received accelerator operation amount and motor rotation speed. In powering control, the controller 31 requests the electric motor 6 to generate a drive torque for traveling the vehicle 1. More specifically, in powering control, the controller 31 generates a control command for causing the electric motor 6 to generate a drive torque that is a torque in a predetermined forward direction, and outputs the control command to the inverter 32. Note that the forward direction of the electric motor 6 is the rotation direction of the electric motor 6 that generates a drive torque that accelerates the vehicle 1 forward. The inverter 32 is controlled by the controller 31 to convert the DC power discharged from the battery 3a into AC power and supply it to the electric motor 6.

[0020] In the regenerative control, the controller 31 requests the electric motor 6 to generate a regenerative torque. More specifically, in the regenerative control, the controller 31 generates a regenerative control command and outputs it to the inverter 32. Upon receiving the regenerative control command, the inverter causes the electric motor 6 to generate a regenerative torque, which is a torque in a negative direction opposite to the positive direction, in order to brake the vehicle 1. The inverter 32 also converts the AC power generated by the electric motor 6 as a generator into DC power and supplies it to the battery 3a for charging.

[0021] In terms of functions, the controller 31 has a normal torque acquisition unit 41, a strong regenerative torque acquisition unit 42, a strong regenerative selection unit 43, a torque determination unit 44, etc. The normal torque acquisition unit 41, the strong regenerative torque acquisition unit 42, the strong regenerative selection unit 43, and the torque determination unit 44 are realized by the processor processing the program read from the storage to the main memory. The normal torque acquisition unit 41, the strong regenerative torque acquisition unit 42, the strong regenerative selection unit 43, and the torque determination unit 44 execute driving control of the vehicle 1 that switches between powering control and regenerative control.

[0022] The normal torque acquisition unit 41 acquires a torque corresponding to the accelerator operation amount and the motor rotation speed using the normal torque map. The strong regenerative torque acquisition unit 42 acquires a torque corresponding to the accelerator operation amount and the motor rotation speed using the strong regenerative torque map. The torque acquired by the normal torque acquisition unit 41 using the normal torque map is referred to as normal torque T1. The torque acquired by the strong regenerative torque acquisition unit 42 using the strong regenerative torque map is referred to as strong regenerative torque T2. The normal torque map and the strong regenerative torque map are stored in the memory of the controller 31. Both the normal torque map and the strong regenerative torque map indicate the correspondence between the accelerator operation amount and the motor rotation speed, and the torque.

[0023] The normal torque map may be referred to as a first torque map. The strong regenerative torque map may be referred to as a second torque map. The strong regenerative torque map is set to provide a larger regenerative torque than the regenerative torque obtained from the normal torque map, even under the same conditions of the motor rotation speed and accelerator operation amount. Details of the maps will be described later. The normal torque acquisition unit 41 and the strong regenerative torque acquisition unit 42 output the torque information obtained from each map to the torque determination unit 44.

[0024] The normal torque acquisition unit 41 outputs the acquired torque information to the strong regenerative selection unit 43. The regenerative selection unit 43 outputs a selection command for selecting or not selecting strong regenerative torque based on the torque information provided by the normal torque acquisition unit 41. In this embodiment, the regenerative selection unit 43 provides a selection command to the torque determination unit 44 for selecting a required torque based on the regenerative torque information from the strong regenerative torque acquisition unit 43 for a predetermined period after the torque information provided by the normal torque acquisition unit 41 is switched to regenerative torque. In other words, the strong regenerative selection unit 43 outputs a selection command indicating whether or not to use the strong regenerative torque information output from the strong regenerative torque acquisition unit 43 based on a predetermined selection condition.

[0025] The torque determination unit 44 determines the required torque Tr required for the electric motor 6. During powering control, the required torque Tr is a positive value, and during regenerative control, the required torque Tr is a negative value. In the following description, the required torque Tr during powering control is also referred to as required drive torque Tr, and the required torque Tr during regenerative control is also referred to as required regenerative torque Tr. Specifically, the torque determination unit 44 outputs the required torque Tr to the inverter 30 based on the torque information provided by the normal torque acquisition unit 41 and the strong regenerative torque acquisition unit 42, respectively, and the selection command provided by the strong regeneration selection unit 43. More specifically, the torque determination unit 44 determines the regenerative torque so as to be different based on the time change (the degree of decrease described later) of the accelerator operation amount before the start of regeneration.

[0026] The torque determination unit 44 determines the required drive torque Tr using the normal torque T1 acquired by the normal torque acquisition unit 41. The torque determination unit 44 also determines the required regenerative torque Tr using both the normal torque T1 acquired by the normal torque acquisition unit 41 and the strong regenerative torque T2 acquired by the strong regenerative torque acquisition unit 42. A method for determining the required torque Tr will be described in detail later. The torque determination unit 44 outputs a control command to the inverter 32 to cause the electric motor 6 to generate the determined required torque Tr.

[0027] The normal torque map and the strong regenerative torque map will be described with reference to Fig. 3. Two normal torque maps M1a, M1b and one strong regenerative torque map M2 are illustrated in Fig. 3. Each torque map shown in Fig. 3 is shown as a graph indicating the correspondence between motor rotation speed and torque for each accelerator operation amount, with the horizontal axis indicating motor rotation speed and the vertical axis indicating torque.

[0028] The normal torque map M1a shown by a solid line in Fig. 3 indicates the relationship between the motor rotation speed and normal torque T1 when the accelerator operation amount is 50%. The normal torque map M1b shown by a dashed line in Fig. 3 indicates the relationship between the motor rotation speed and normal torque T1 when the accelerator operation amount is 0%. The strong regenerative torque map M2 shown by a dashed line in Fig. 3 indicates the relationship between the motor rotation speed and strong regenerative torque T2 when the accelerator operation amount is 0%. In each torque map, a positive torque value indicates a drive torque that drives the drive wheels, and a negative torque value indicates a regenerative torque that brakes the drive wheels. The negative normal torque T1 may also be referred to as a normal regenerative torque T1.

[0029] The normal torque map is set so that the torque in the positive direction increases as the accelerator operation amount increases. For example, Fig. 3 shows a normal torque map M1a where the accelerator operation amount is 50%, but a normal torque map where the accelerator operation amount is more than 50% is located in the area above the graph M1a in Fig. 3, and a normal torque map where the accelerator operation amount is less than 50% is located in the area below the graph M1a in Fig. 3.

[0030] Moreover, the normal torque map is set so that the positive torque (driving torque) decreases as the motor rotation speed increases, even for the same accelerator operation amount (see normal torque map M1a in FIG. 3). The normal torque map is set so that when the accelerator operation amount is zero, regenerative torque occurs when the motor rotation speed is equal to or higher than a predetermined creep speed A. The normal torque map is set so that when the accelerator operation amount is zero, the regeneration amount differs according to the motor rotation speed. For example, the motor rotation speed is set to be maximum at a predetermined maximum regeneration amount speed B, and the regeneration amount decreases as the motor rotation speed deviates from the maximum speed B (see normal torque map M1b in FIG. 3).

[0031] The normal torque map interpolates torque based on data for each adjacent torque rotation speed. In FIG. 3, two normal torque maps M1a and M1b are shown, but in reality, a plurality of normal torque maps corresponding to a plurality of accelerator operation amount values ​​(for example, a plurality of accelerator operation amounts of 0%, 10%, 20%, ..., 100%) are pre-stored in the memory. For example, when the accelerator operation amount is 2%, the torque corresponding to the accelerator operation amount of 2% is obtained by linearly interpolating the torque obtained in the normal torque map with the accelerator operation amount of 0% and the torque obtained in the normal torque map with the accelerator operation amount of 10%. Therefore, in the normal torque map of this embodiment, even if the accelerator operation amount is a value exceeding zero, if the accelerator operation amount is a small value such as 5% or less, the torque corresponding to the motor rotation speed near the maximum regeneration amount speed is set to a negative value, that is, a regeneration torque. In this way, even in the normal torque map other than when the accelerator operation amount is 0%, the normal torque T1 can take a negative value in the entire range or a part of the range of the motor rotation speed.

[0032] In the strong regenerative torque map, when the accelerator operation amount is zero, the regenerative torque is set to be larger than that in the normal torque map under the same motor rotation speed condition. For example, as can be seen from a comparison between the normal torque map M1b where the accelerator operation amount is 0% and the strong regenerative torque map M2, when the normal regenerative torque T1 and the strong regenerative torque T2 corresponding to the same accelerator operation amount and the same motor rotation speed are compared, the absolute value of the strong regenerative torque T2 is smaller than the absolute value of the normal regenerative torque T1. In other words, the strong regenerative torque map is a torque map for obtaining a stronger regenerative braking force than the normal torque map. For example, the strong regenerative torque map may be set to generate a regenerative torque when the motor rotation speed exceeds zero. Also, in the strong regenerative torque map, the regenerative amount is set to be maximum at a motor rotation speed C that is higher than the maximum regenerative amount speed B set in the normal torque map, and the regenerative amount is set to be smaller as the motor rotation speed deviates from the maximum speed C (see the strong regenerative torque map M2 in FIG. 3). In this way, the strong regenerative torque map is set to generate a regenerative torque larger than the regenerative torque of the normal torque map.

[0033] In addition, in FIG. 3, a strong regenerative torque map M2 showing the correspondence relationship between the motor rotation speed and the strong regenerative torque T2 when the accelerator operation amount is 0% is shown, but a plurality of strong regenerative torque maps corresponding to a plurality of values ​​of the accelerator operation amount may be stored in advance in the memory. However, since the strong regenerative torque map is a map used when the regenerative control is executed, only a map corresponding to the accelerator operation amount for which the regenerative control can be executed is prepared. For example, if the normal torque map for the accelerator operation amount of 5% or less includes a torque of a negative value, a plurality of strong regenerative torque maps for the accelerator operation amount of 5% or less may be prepared. For example, a torque map in which the torque is zero at any motor rotation speed may be prepared as a strong regenerative torque map for the accelerator operation amount of a predetermined positive infinitesimal value. In this case, the torque corresponding to the accelerator operation amount between 0% and the infinitesimal value may be obtained by linearly interpolating the torque obtained in the strong regenerative torque map for the accelerator operation amount of 0% and the torque obtained in the normal torque map for the accelerator operation amount of the infinitesimal value.

[0034] (Drive control) Next, the driving control of the vehicle 1 by the controller 31 will be described with reference to Figures 4 and 5. The driving control of the vehicle 1 by the controller 31 is performed by the controller 31 reading and executing a program stored in the memory of the controller 31. The controller 31 switches between power control and regenerative control of the electric motor 6 according to the accelerator operation amount and motor rotation speed that are acquired.

[0035] Specifically, in the driving control, the controller 31 receives the accelerator operation amount from the accelerator sensor 21, and receives the motor rotation speed from the rotation speed sensor 22 (step S1).

[0036] The controller 31, more specifically the normal torque obtaining unit 41, obtains a normal torque T1 corresponding to the accelerator operation amount and the motor rotation speed by using a normal torque map (step S2).

[0037] The controller 31, more specifically the strong regeneration selection unit 43, determines whether or not a predetermined regeneration start condition is satisfied (step S3). In this embodiment, the regeneration start condition is set to a condition that the normal torque T1 acquired in step S2 has changed from a positive value to a negative value.

[0038] If it is determined that the regeneration start condition is not satisfied (step S3: No), the controller 31, more specifically the torque determination unit 44, determines the required torque Tr (i.e., the required driving torque Tr) to be the normal torque T1 obtained in step S2 (i.e., Tr=T1), and outputs a control command to the inverter 32 (step S4). After step S4, the process returns to step S1. Thus, if it is determined in step S3 that the regeneration start condition is not satisfied, steps S1, S2, and S4 are repeated, and powering control is performed to generate a driving force for traveling by the electric motor 6 using electric power from the battery 3a.

[0039] When it is determined that the regeneration start condition is satisfied (step S3: Yes), the controller 31 switches the traveling control from the powering control to the regeneration control shown in FIG.

[0040] (Regenerative control overview) The background to the regeneration control method of this embodiment and an overview of the regeneration control method will be described. First, the regeneration control will be described from the viewpoint of comparison with the regeneration control of an engine vehicle using an internal combustion engine as a driving source. For example, when a user driving an engine vehicle performs a sudden closing operation to suddenly reduce the accelerator operation amount from a relatively large value to 0%, a strong engine brake is applied, and the user feels a strong deceleration feeling or a shock immediately after the sudden closing operation. When the user performs an operation to reduce the accelerator operation amount from a relatively small value to 0% or performs an operation to slowly reduce the accelerator operation amount from a relatively large value, the user does not feel a strong deceleration feeling or a shock. When a user who is accustomed to driving an engine vehicle drives an electric vehicle, if the braking feeling during deceleration is far from the braking feeling during deceleration of the engine vehicle as described above, the user may feel uncomfortable.

[0041] Also, when a user performs an operation to suddenly close the vehicle by suddenly decreasing the accelerator operation amount from a relatively large value to 0%, it is highly likely that the user wants to decelerate the vehicle relatively quickly. Also, when a user performs an operation to slowly decrease the accelerator operation amount from a relatively large value, it is highly likely that the user does not want the vehicle to suddenly decelerate. In an electric vehicle, it is desirable to generate a braking force that is in line with the user's intention.

[0042] Also, for example, when a saddle riding vehicle approaches a curve while traveling, the user decelerates the saddle riding vehicle before approaching the curve and steers the saddle riding vehicle. When a large braking force is applied during deceleration, the load on the front wheels is larger than that on the rear wheels. This can lead to improved steering ease of the saddle riding vehicle. From the viewpoint of improving the steering ease of the saddle riding electric vehicle, it is desirable to generate a strong braking force when the user performs a sudden closing operation.

[0043] In order to achieve at least one of these desirable feelings, in the electric vehicle 1 of this embodiment, the absolute value of the required regenerative torque Tr determined within a predetermined period from the start of regenerative control is set to be greater than the absolute value of the required regenerative torque Tr determined after the predetermined period has elapsed.

[0044] More specifically, the controller 31 acquires a degree of decrease d of the accelerator operation amount with the passage of time before the start of the regenerative control. The degree of decrease d is an index for determining the speed of the operation of the accelerator operator 15a by the user when decelerating the vehicle 1 and the magnitude of change in the operation amount. In other words, the degree of decrease d indicates how the accelerator operation amount has decreased during the period up to the start of the regenerative control. In other words, the degree of decrease d is an index for determining the degree of deceleration intended by the user. In other words, the degree of decrease d may be the time change per unit time of the accelerator operation that returns the accelerator operator 15a to the reference position, or the time change per unit time of the deceleration operation.

[0045] The controller 31 determines the required regenerative torque Tr based on the degree of decrease d of the accelerator operation amount. Specifically, when the degree of decrease d is large, the controller 31 increases the required regenerative torque Tr over time in accordance with the degree of decrease d of the accelerator operation amount. The greater the degree of decrease d, the greater the required regenerative torque Tr that increases per unit time. When the required regenerative torque Tr reaches a predetermined upper limit, the controller 31 maintains the required regenerative torque Tr at the upper limit. In this embodiment, the predetermined upper limit corresponds to a strong regenerative torque T2 obtained by referring to a strong regenerative torque map M2, as described later. That is, in this embodiment, the upper limit can change with changes in the accelerator operation amount and the rotation speed of the electric motor 6 (see also the dashed graph in FIG. 3).

[0046] The controller 31 determines whether a predetermined regeneration reduction condition is satisfied while the required regeneration torque Tr is maintained at the upper limit value or while the required regeneration torque Tr is being increased based on the degree of decrease d of the accelerator operation amount. In this embodiment, the regeneration reduction condition corresponds to a condition that a regeneration time t, which will be described later, reaches a set time ts.

[0047] When the controller 31 determines that the regeneration reduction condition is satisfied, the controller 31 reduces the required regenerative torque Tr over time. When the required regenerative torque Tr reaches a predetermined lower limit, the controller 31 maintains the required regenerative torque Tr at the lower limit. In this embodiment, the predetermined lower limit corresponds to a normal regenerative torque T1 obtained by referring to a normal torque map M1b as described later. That is, in this embodiment, the lower limit can change with changes in the accelerator operation amount and the rotation speed of the electric motor 6 (see also the dashed-dotted graph in FIG. 3).

[0048] (Details of regenerative control) 5 is a flowchart showing the flow of regeneration control. First, the controller 31 counts the time elapsed from the start of regeneration control, that is, the time elapsed from the time when the regeneration start condition is satisfied (step S11). In the following description, the time elapsed from the time when the regeneration start condition is satisfied is referred to as the regeneration time t.

[0049] The controller 31, more specifically the torque determination unit 44, calculates the degree of decrease d of the accelerator operation amount with the passage of time before the start of regenerative control, that is, before the time when the regenerative start condition is satisfied (step S12). The degree of decrease d of the accelerator operation amount is used to determine the required regenerative torque Tr for a predetermined period from the start of regenerative control. The predetermined period is the period from the start of regenerative control until a coefficient k, which will be described later, reaches 0.

[0050] Fig. 6 is a graph for explaining an example of a method for calculating the degree of decrease d. The graph shown by the solid line in Fig. 6 is a graph showing time series data of the accelerator operation amount received from the accelerator sensor 21, with the horizontal axis being the time axis and the vertical axis being the accelerator operation amount. The dashed line in Fig. 6 is the time series data of the accelerator operation amount received from the accelerator sensor 21 subjected to low-pass filter processing. The time series data of the accelerator operation amount received from the accelerator sensor 21 is referred to as "pre-filter processing data", and data obtained by applying low-pass filter processing to the time series data of the accelerator operation amount received from the accelerator sensor 21 is referred to as "filter processing data".

[0051] The filtered data changes later than the unfiltered data because the filtered data has been subjected to low-pass filtering. In this embodiment, the controller 31 determines the degree of decrease d to be the difference in the accelerator operation amount obtained by subtracting the value of the unfiltered data at the start of regenerative control from the value of the filtered data at the start of regenerative control.

[0052] However, the degree of decrease d does not have to be the difference between the value of the filtered data and the value of the unfiltered data at the same time. For example, the degree of decrease d may be the difference in the accelerator operation amount obtained by subtracting the value of the unfiltered data at the start of the regenerative control from the value of the filtered data a predetermined time before the start of the regenerative control (for example, the control period of the controller 31).

[0053] Returning to Fig. 5, the controller 31, more specifically the torque determination unit 44, initializes the coefficient k to 0 (step S13). The coefficient k can take a value of 0 or more and 1 or less. As will be described later, in the regenerative control of this embodiment, the coefficient k varies over time between 0 or more and 1 or less, and the required regenerative torque Tr required of the electric motor 6 is calculated using this coefficient k.

[0054] The controller 31, more specifically, the normal torque acquisition unit 41, acquires a normal torque T1 corresponding to the accelerator operation amount and the motor rotation speed using a normal torque map (step S14). Also, the controller 31, more specifically, the strong regenerative torque acquisition unit 42 acquires a strong regenerative torque T2 corresponding to the accelerator operation amount and the motor rotation speed using a strong regenerative torque map (step S15).

[0055] The controller 31, more specifically the strong regeneration selection unit 43, determines whether the regeneration time t is less than the set time ts (step S16). If it is determined that the regeneration time t is less than the set time ts (step S16: Yes), the controller 31 determines whether the coefficient k has reached 1 (step S17). If the coefficient k has not reached 1 (step S17: No), the controller 31 increases the coefficient k at a rate of change according to the decrease degree d acquired in step S12 (step S18) and proceeds to step S21.

[0056] Correspondence information indicating the correspondence between the degree of decrease d and the rate of change of the coefficient k is stored in advance in the memory of the controller 31. The rate of change of the coefficient k is the amount of increase of the coefficient k per unit time. The controller 31 refers to the correspondence information stored in the memory, acquires the rate of change corresponding to the acquired degree of decrease d, and increases the coefficient k by the acquired rate of change. The degree of decrease d and the rate of change of the coefficient k have a relationship such that the greater the degree of decrease d, the greater the rate of change (time increase rate) of the coefficient k.

[0057] The correspondence relationship information indicating the correspondence relationship between the decrease degree d and the rate of change of the coefficient k when the regeneration time t is less than the set time ts may be information indicating the relationship that the rate of change of the coefficient k is the product of the decrease degree d and a predetermined positive value α1. In other words, the coefficient k may increase by the value of α1×d per unit time. In this case, the coefficient k may be calculated by multiplying the predetermined positive value α1, the decrease degree d, and the regeneration time t, that is, it may be calculated by the following calculation formula (1). k = α1 d t (1)

[0058] If the coefficient k has reached 1 in step S17 (step S17: Yes), the controller 31 does not change the coefficient k, but keeps it at 1, and proceeds to step S21.

[0059] If it is determined in step S16 that the regeneration time t is not less than the set time ts (step S16: No), the controller 31 determines whether or not the coefficient k has reached 0 (step S19). If the coefficient k has not reached 0 (step S19: No), the controller 31 reduces the coefficient k (step S20) and proceeds to step S21.

[0060] In step S20, the coefficient k may be decreased over time based on the decrease degree d. In this case, correspondence relationship information indicating the correspondence relationship between the decrease degree d and the rate of change of the coefficient k when the regeneration time t exceeds the set time ts may also be stored in advance in the memory of the controller 31. The information may indicate a relationship in which the rate of change of the coefficient k is the product of the decrease degree d and a predetermined negative value (-α2). In other words, the coefficient k may be decreased by the value of α2×d per unit time. In this case, the coefficient k may be calculated by multiplying the predetermined negative value (-α2), the decrease degree d, and the elapsed time (t-ts) from the set time ts, that is, it may be calculated by the following calculation formula (2). k = -α2 d (t-ts) (2)

[0061] If the coefficient k has reached 0 in step S19 (step S19: Yes), the controller 31 does not change the coefficient k, but keeps it at 0, and proceeds to step S21.

[0062] The controller 31, more specifically the torque determination unit 44, calculates the required torque Tr using the coefficient k obtained through steps S16, S17, S18, S19, and S20, the normal torque T1 obtained in step S14, and the strong regenerative torque T2 obtained in step S15, according to the following equation (3), and outputs a control command to the inverter 32 (step S21). Tr = (1-k) T1 + k T2 (3)

[0063] That is, the required regenerative torque Tr is calculated by adding the strong regenerative torque T2 multiplied by the coefficient k to the normal regenerative torque T1 multiplied by the coefficient (1-k). In this way, the required torque Tr is calculated using the normal torque T1 and the strong regenerative torque T2. Furthermore, the above formula (3) indicates that the larger the coefficient k, the larger the proportion of the strong regenerative torque T2 in the required torque Tr. In other words, the above formula (3) indicates that the larger the coefficient k, the larger the magnitude (i.e., absolute value) of the required regenerative torque Tr.

[0064] The controller 31, more specifically the torque determination unit 44, receives the accelerator operation amount from the accelerator sensor 21 and the motor rotation speed from the rotation speed sensor 22 (step S22). The controller 31 determines whether or not a regeneration end condition is satisfied (step S23). The regeneration end condition may be set to a condition that the normal torque T1 becomes a positive value, or may be a condition that the accelerator operation amount exceeds a predetermined value (for example, 5% of the accelerator operation amount). The regeneration end condition may be another condition. For example, it may be a user operation such as a brake operation or a clutch operation.

[0065] When it is determined that the regeneration end condition is not satisfied (step S23: No), the process returns to step S14. Thus, when it is determined in step S23 that the regeneration end condition is not satisfied, the steps from step S14 to step S23 are repeated to make the electric motor 6 generate a regeneration torque corresponding to the required regeneration torque Tr.

[0066] When it is determined that the regeneration end condition is satisfied (step S23: Yes), the controller 31 switches the traveling control from regeneration control to powering control.

[0067] (Change in coefficient k according to the degree of decrease d) Fig. 7 shows an example of the change in coefficient k over time. In Fig. 7, the horizontal axis indicates the regeneration time t, which is the time elapsed since the regeneration start condition was satisfied, and the vertical axis indicates the coefficient k. In Fig. 7, the solid line shows an example of the change in coefficient k when a relatively large decrease degree d is obtained, and the dashed line shows an example of the change in coefficient k when a relatively small decrease degree d is obtained.

[0068] First, the change in coefficient k when the degree of decrease d is relatively large will be described. As shown by the solid line graph in Fig. 7, when the regeneration start condition is satisfied, coefficient k increases at a rate of change according to the degree of decrease d as time passes from the time of regeneration time t = 0 (see step S18 in Fig. 5). As described above, the rate of change is obtained from the correspondence information stored in the memory of controller 31, which indicates the correspondence between the degree of decrease d and the rate of change of coefficient k. The rate of change according to the degree of decrease d corresponds to the slope of the solid line graph from the time of regeneration time t = 0 to the time of regeneration time t = t1 in Fig. 7.

[0069] As shown by the solid line graph in Fig. 7, when the coefficient k reaches 1 at the time of regeneration time t=t1, the coefficient k is maintained at 1 until the regeneration time t reaches the set time ts (see step S17 in Fig. 5). While the coefficient k is maintained at 1, the required torque Tr becomes the strong regeneration torque T2 according to the above formula (3).

[0070] As shown by the solid line graph in FIG. 7, when the regeneration time t reaches the set time ts, the coefficient k decreases at a constant rate of change over time (see step S20 in FIG. 5). In this embodiment, the strong regeneration end time t2 is set in advance. The strong regeneration end time t2 is a fixed value. The coefficient k decreases at a constant rate of change over time so as to reach 0 at the strong regeneration end time t2. After the coefficient k reaches 0, the required torque Tr becomes the normal regeneration torque T1.

[0071] Next, the change in coefficient k when the degree of decrease d is relatively small will be described. Even when the degree of decrease d is relatively small, coefficient k increases at a rate of change according to the degree of decrease d as time passes from the regeneration time t=0 as shown by the dashed line graph in Fig. 7, but in the period from the regeneration time t=0 to the regeneration time t=t1, the slope of the dashed line graph is smaller than the slope of the solid line graph. This is because, in the correspondence relationship information showing the correspondence relationship between the degree of decrease d and the rate of change of coefficient k, the greater the degree of decrease d, the greater the rate of change of coefficient k.

[0072] In the dashed line graph in Fig. 7, the regeneration time t reaches the set time ts without the coefficient k reaching 1. When the regeneration time t reaches the set time ts, the coefficient k decreases at a constant rate over time so that the coefficient k reaches 0 when the regeneration time t reaches the strong regeneration end time t2. After the coefficient k reaches 0, the required torque Tr becomes the normal regeneration torque T1.

[0073] (Action and effect) As described above, according to this embodiment, the controller 31 acquires the degree of decrease d in the accelerator operation amount over time before the start of regenerative control, and determines the required regenerative torque Tr, which is the regenerative torque required of the electric motor 6, based on the degree of decrease d in the accelerator operation amount. For this reason, the regenerative torque is made different depending on the accelerator operation by the user. Since a braking force corresponding to the user operation can be generated when regenerative control is executed, the braking feeling felt by the user can be made closer to the feeling intended by the user.

[0074] In this embodiment, the strong regenerative torque map is used at least for a predetermined period from the start of regenerative control. At least for a predetermined period from the start of regenerative control, the required regenerative torque Tr is determined based on the degree of decrease d of the accelerator operation amount. This makes it possible to make the braking feeling immediately after the start of regenerative control closer to the feeling intended by the user.

[0075] In this embodiment, as described above, the correspondence information stored in the memory is set so that the greater the decrease d, the greater the time increase rate of the coefficient k. The required regenerative torque Tr is determined using the above formula (3), in which the greater the coefficient k, the greater the absolute value of the required regenerative torque Tr. That is, the greater the decrease d in the accelerator operation amount, the greater the required regenerative torque Tr is made. This makes it possible to make the braking feeling felt by the user when regenerative control is executed closer to the braking feeling when the engine brake is activated in an engine vehicle. This makes it easier to prevent a user who is accustomed to driving an engine vehicle from feeling strange.

[0076] Furthermore, in this embodiment, the coefficient k increases in step S18 from the start of regenerative control until the condition that the coefficient k reaches 1 is satisfied. As a result, the required regenerative torque Tr increases over time from the start of regenerative control until the predetermined condition is satisfied, so that the shock to the vehicle body can be reduced compared to when the regenerative torque is suddenly changed.

[0077] In this embodiment, the rate of change of the coefficient k increases as the degree of decrease d of the accelerator operation amount increases. This increases the increase in the required regenerative torque Tr per unit time as the degree of decrease d of the accelerator operation amount increases, so that the braking feeling can be made closer to the braking feeling when the engine brake is activated in an engine vehicle, making it easier to prevent a sense of discomfort for users who are accustomed to driving engine vehicles.

[0078] In addition, in this embodiment, when the coefficient k reaches 1, the coefficient k is maintained at 1. In other words, the required regenerative torque Tr is maintained at the strong regenerative torque T2, which is the upper limit value. In this way, since the upper limit value of the regenerative torque is set, it is possible to prevent the braking force due to the regenerative torque from becoming excessive. Furthermore, since the upper limit value changes according to the rotation speed of the electric motor 6, it is possible to limit the regenerative torque of the electric motor 6 to a range suitable for the rotation speed.

[0079] Furthermore, in this embodiment, after the regenerative time t reaches the set time ts, that is, after it is determined that the regenerative reduction condition is satisfied, the regenerative torque decreases over time, thereby reducing the shock to the vehicle body compared to when the regenerative torque is suddenly reduced.

[0080] In this embodiment, the absolute value of the required regenerative torque Tr determined during the predetermined period from the start of regenerative control is greater than the absolute value of the required regenerative torque Tr determined after the predetermined period has elapsed. Therefore, a relatively large regenerative torque can be provided from the start of regenerative control until the predetermined period, and a braking feeling that matches the user's deceleration intention can be generated.

[0081] In this embodiment, a coefficient k (where 0≦k≦1) is determined so that the regenerative torque increases over time as the degree of decrease in the accelerator operation amount increases, and the regenerative torque is determined by adding a value obtained by multiplying the strong regenerative torque by the coefficient k to a value obtained by multiplying the normal regenerative torque by a coefficient (1-k). Therefore, with a simple control logic, the regenerative torque can be increased as the degree of decrease in the accelerator operation amount increases.

[0082] <Other embodiments> The present disclosure is not limited to the above-described embodiments, and the configuration can be changed, added, or deleted.

[0083] For example, the vehicle described in the above embodiment is an electric vehicle equipped with one driving source, but the vehicle is not limited to this. For example, the vehicle may be a hybrid vehicle equipped with two driving sources, an electric motor and an internal combustion engine. That is, the regenerative control method of the present disclosure is also applicable to a hybrid vehicle. In a hybrid vehicle, the above-mentioned regenerative control may be executed while the vehicle is traveling by motor drive. In addition, the saddle-riding vehicle does not have to be a two-wheeled vehicle, but may be a three-wheeled vehicle. In addition, the vehicle does not have to be a saddle-riding vehicle, but may be, for example, a four-wheeled vehicle. The vehicle may be equipped with a transmission that switches the gear ratio. The regenerative control method of the present disclosure is applicable to vehicles in general. In addition, the regenerative control method of the present disclosure can be suitably applied to a saddle-riding vehicle that is relatively lighter than a four-wheeled vehicle and has a large effect on the feeling due to the regenerative control.

[0084] In the above embodiment, the regeneration start condition is a condition determined using the accelerator operation amount, the motor rotation speed, and the normal torque map, but the regeneration start condition is not limited to this. For example, the regeneration start condition may be a condition that the accelerator operation amount is zero or is equal to or less than a predetermined value (for example, 5% of the accelerator operation amount). In the above embodiment, the regeneration control start condition is determined based on the accelerator operation amount, but the regeneration control start condition may be determined based on other conditions than the accelerator operation amount. For example, the regeneration control start condition may include a condition that a brake operation is performed on a brake operator.

[0085] In addition, when the vehicle is equipped with a transmission that switches the gear ratio by a user's gear shifting operation, the start condition of the regenerative control may include a condition that the user's gear shifting operation is a predetermined operation. In this way, the start of the regenerative control may be determined based on the user's operation. The start condition of the regenerative control may also be determined based on a plurality of user operations such as an accelerator operation amount, a brake operation amount, and a gear shift operation amount. The regenerative start condition may also be corrected or changed based on the vehicle state such as the vehicle speed, the motor rotation speed, and the gear ratio. For example, the regenerative start condition may be set so that the regenerative control starts earlier as the vehicle speed or the motor rotation speed increases. The necessity of the regenerative control may be determined according to the battery state. The regenerative start condition may be set so that the start of the regenerative control is prevented when it is determined that the battery or the circuit will be damaged, for example, when the battery's state of charge (SOC) is high or the temperature of the electric wire is excessive.

[0086] In the above embodiment, the regeneration reduction condition is that the regeneration time t reaches the set time ts, but the regeneration reduction condition is not limited to this. For example, the regeneration reduction condition may be that either the regeneration time t reaches the set time ts or the coefficient k reaches 1 is satisfied. The regeneration reduction condition may also be set according to the vehicle speed or the motor rotation speed.

[0087] In the above embodiment, the strong regeneration torque map is used during the strong regeneration end time t2, which is a predetermined period from the start of the regeneration control. The strong regeneration end time t2 is a fixed value set in advance, but the predetermined period is not limited to this. The strong regeneration end time t2 may be a variable value. For example, the strong regeneration end time t2 may be set to be larger as the decrease degree d increases. Alternatively, the strong regeneration end time t2 may be set to be larger as the magnitude of the coefficient k at the time when the regeneration time t reaches the set time ts increases. The rate of change of the coefficient k with the passage of time after the regeneration time t reaches the set time ts may be a fixed value, and thus the strong regeneration end time t2 may depend on the magnitude of the coefficient k at the time when the regeneration time t reaches the set time ts.

[0088] In the above embodiment, two torque maps, a strong regenerative torque map and a normal torque map, are used, and the coefficient k, which is the ratio of the strong regenerative torque T2 to the required torque Tr, is increased over time as the decrease degree d increases, thereby increasing the required regenerative torque as the decrease degree d increases. The method of determining the required regenerative torque, which is increased as the decrease degree d increases, is not limited to this.

[0089] For example, in the above embodiment, both the strong regenerative torque map and the normal torque map are used for a predetermined period from the start of regenerative control, but only the normal torque map may be used. In this case, the normal regenerative torque is obtained from the normal torque map, and during the predetermined period from the start of regenerative control, a value obtained by adding an additional torque according to the magnitude of the decrease degree d to the normal regenerative torque obtained from the normal torque map may be used as the required regenerative torque. Alternatively, a value obtained by multiplying the normal regenerative torque obtained from the normal torque map by a value (however, a value equal to or greater than 1) according to the magnitude of the decrease degree d may be used as the required regenerative torque.

[0090] For example, in the above embodiment, both the strong regenerative torque map and the normal torque map were used for a predetermined period from the start of regenerative control, but only the strong regenerative torque map may be used, in which case the value obtained by referring to the strong regenerative torque map may be used as the required regenerative torque.

[0091] For example, in the above embodiment, two types of regenerative torque (i.e., normal regenerative torque and strong regenerative torque) are obtained using two torque maps, a strong regenerative torque map and a normal torque map, but the normal regenerative torque and the strong regenerative torque may be obtained by a method other than the torque maps. The normal regenerative torque and the strong regenerative torque may be calculated by different calculation formulas, for example, with different coefficients.

[0092] In the above embodiment, the normal torque map and the strong regenerative torque map show the correspondence relationship between the accelerator operation amount and the motor rotation speed, and the torque, but the normal torque map and the strong regenerative torque map are not limited to this. The normal torque map and the strong regenerative torque map may show the correspondence relationship between the accelerator operation amount and the motor rotation speed, and the torque, or both of the normal torque map and the strong regenerative torque map may show the correspondence relationship between the accelerator operation amount and the motor rotation speed, and the torque.

[0093] In the above embodiment, the required regenerative torque Tr is maintained so as not to exceed a predetermined upper limit, and this upper limit corresponds to the strong regenerative torque T2 obtained by referring to the strong regenerative torque map M2, but the upper limit is not limited to this. The upper limit does not need to change according to the accelerator operation amount or the motor rotation speed. For example, the upper limit may be a fixed value set in advance.

[0094] In the regenerative control of the above embodiment, acquiring the degree of decrease in the accelerator operation amount over time before the start of the regenerative control includes performing low-pass filtering on the acquired accelerator operation amount, and calculating the degree of decrease in the accelerator operation amount by subtracting the acquired accelerator operation amount from the accelerator operation amount after the low-pass filtering. However, the method of acquiring the degree of decrease is not limited to this. In the above embodiment, the degree of decrease d is the difference in the accelerator operation amount obtained by subtracting the value of the pre-filter processing data at the start of the regenerative control from the value of the post-filter processing data at the start of the regenerative control, as described with reference to FIG. 6. However, the degree of decrease may be any value that is correlated with the time rate of change of the accelerator operation amount, and other indices indicating the degree of decrease in the accelerator operation amount may be used.

[0095] For example, the degree of decrease in the accelerator operation amount may be calculated based on the difference between the accelerator operation amount at the start of the regenerative control and the accelerator operation amount acquired a predetermined time before the start of the regenerative control. However, in this case, if the predetermined time is set to a relatively small value, only the user's operation immediately before the start of the regenerative control is reflected in the degree of decrease in the accelerator operation amount. For this reason, for example, the difference in the calculated degree of decrease is unlikely to be seen between a case where the accelerator operation amount is suddenly closed from a state where the accelerator operation amount is fully open (100%) and a case where the accelerator operation amount is suddenly closed from a state where the accelerator operation amount is 20%. On the other hand, if the predetermined time is set to a relatively large value, the user's operation performed during the predetermined time is not reflected in the degree of decrease in the accelerator operation amount. For example, the difference in the calculated degree of decrease is unlikely to be seen between a case where the accelerator operation amount is slowly decreased from a point in time before the start of the regenerative control and a case where the accelerator operation amount is increased once from a point in time before the start of the regenerative control and then decreased. Therefore, it is preferable to calculate the degree of reduction in the accelerator operation amount by subtracting the acquired accelerator operation amount from the accelerator operation amount after low-pass filter processing, from the viewpoint of making it easier for the user's operation to be reflected in the degree of reduction in the acquired accelerator operation amount.

[0096] In the above embodiment, when the coefficient k is gradually changed, it is changed linearly so as to increase by a fixed amount per unit time as shown in Fig. 7, but the coefficient k may be changed nonlinearly or in a stepwise manner. Also, the coefficient k may be changed instantaneously instead of gradually changing it by tailing.

[0097] In the above embodiment, the required torque Tr is calculated by the formula (3), but the calculation formula of the required torque Tr is only an example. The required torque Tr may be determined by other methods. Even in this case, it is preferable to increase the regenerative torque at the initial stage of the start of regeneration as the degree of decrease in the accelerator operation amount increases. In addition, in this embodiment, the increase amount of the regenerative torque (the time change rate of the regenerative torque) in which the regenerative torque increases with time from the start of regeneration as the degree of decrease in the accelerator operation amount increases, but this is not limited to this. For example, it is sufficient that the maximum value of the regenerative torque is larger when the degree of decrease in the accelerator operation amount is larger, and the time change rate of the regenerative torque may be the same regardless of the degree of decrease in the accelerator operation amount. For example, the required regenerative torque may be determined to be the maximum regenerative torque at the start of regeneration, rather than gradually increasing from the start of regeneration. Even in this case, it is preferable to determine the maximum regenerative torque to be larger as the degree of decrease in the accelerator operation amount increases.

[0098] In the above embodiment, the strong regenerative torque is set based on the motor rotation speed and the accelerator operation amount, but the strong regenerative torque is not limited thereto and may be any value that generates a regenerative amount larger than the regenerative amount of the normal torque map. By setting a strong regenerative torque of a value different from the regenerative torque obtained by the normal torque map based on the motor rotation speed and the accelerator operation amount, it is possible to easily obtain a regenerative torque that differs depending on the situation, and to easily get closer to the braking feeling that the user prefers.

[0099] In the above embodiment, the battery is removable, but the battery does not have to be removable. The electric motor does not have to be located between the front and rear wheels. For example, the electric motor may be an in-wheel motor. The electric motor may be located on a swing arm that supports the rear wheels. In the above embodiment, an AC motor is exemplified as the electric motor, but it may be a DC motor. The vehicle may be equipped with a separate motor for driving and a motor for braking. The body frame that supports the electric motor and the battery can be modified as appropriate.

[0100] The meter device 8 may display information indicating that the vehicle is in a regenerative control state in which regenerative control is being executed. In this case, the controller 31 sends a command to the meter device 8 to display that the vehicle is in a regenerative control state. Furthermore, when displaying that the vehicle is in a regenerative control state, the meter device 8 may display information in a different manner depending on whether the regenerative braking is strong or weak. In this case, the controller 31 sends information to the meter device 8 indicating whether the regenerative braking is strong or weak.

[0101] The functions of the elements disclosed herein can be performed using circuits or processing circuits, including general purpose processors, special purpose processors, integrated circuits, Application Specific Integrated Circuits (ASICs), conventional circuits, or any combination thereof, configured or programmed to perform the disclosed functions. Processors are considered processing circuits or circuits because they include transistors and other circuits. In this disclosure, a circuit, unit, or means is hardware that performs the recited functions or hardware that is programmed to perform the recited functions. The hardware may be hardware disclosed herein or other known hardware that is programmed or configured to perform the recited functions. Where the hardware is a processor, which is considered a type of circuit, the circuit, means, or unit is a combination of hardware and software, and the software is used to configure the hardware or processor.

[0102] A program including instructions for carrying out the methods disclosed herein may be stored in a non-transitory computer-readable storage medium, including, for example, a magnetic disk such as a hard disk drive, an optical disk such as a CD-ROM, a DVD disk, or a Blu-ray disk, a read-only memory (ROM), a random access memory (RAM), an EPROM, an EEPROM, a magnetic card, a flash memory, an optical card, or any type of medium suitable for storing electronic instructions.

[0103] [Disclosure form] Each of the following aspects is a disclosure of a preferred embodiment.

[0104] [Aspect 1] A regenerative control method executed in a processing circuit of a vehicle having an electric motor as a drive source, comprising: determining whether a regenerative control initiation condition that requests the electric motor to generate a regenerative torque is satisfied; Obtaining a degree of decrease in accelerator operation amount over time before the start of the regenerative control; and A regenerative control method for a vehicle comprising: determining a required regenerative torque, which is the regenerative torque required of the electric motor, based on the degree of decrease in the accelerator operation amount.

[0105] According to the method, the regenerative torque is varied according to the accelerator operation by the user. Since a braking force corresponding to the user operation can be generated when the regenerative control is executed, the braking feeling felt by the user can be made closer to the feeling intended by the user.

[0106] [Aspect 2] 2. The vehicle regenerative control method according to aspect 1, wherein determining the required regenerative torque based on the degree of decrease in the accelerator depression amount is performed for a predetermined period from the start of the regenerative control.

[0107] According to the above method, the required regenerative torque is determined based on the degree of decrease in the accelerator operation amount, at least for a predetermined period from the start of regenerative control, so that the braking feeling immediately after the start of regenerative control can be made to be closer to the feeling intended by the user.

[0108] [Aspect 3] The vehicle regenerative control method according to aspect 1 or 2, wherein determining the required regenerative torque based on the degree of decrease in the accelerator operation amount includes increasing the required regenerative torque as the degree of decrease in the accelerator operation amount increases.

[0109] According to the method, the regenerative torque increases as the accelerator operation amount decreases, so the braking feeling felt by the user when the regenerative control is executed can be made to be closer to the braking feeling felt when the engine brake is activated in an engine vehicle, which makes it easier to prevent discomfort felt by users who are accustomed to driving engine vehicles.

[0110] [Aspect 4] A regenerative control method for a vehicle described in any one of aspects 1 to 3, wherein determining the required regenerative torque based on the degree of decrease in the accelerator operation amount includes increasing the required regenerative torque over time from the start of the regenerative control to the point at which a predetermined condition is satisfied.

[0111] According to the above method, the regenerative torque generated by the electric motor increases over time, so shocks to the vehicle body can be reduced compared to when the regenerative torque is suddenly changed.

[0112] [Aspect 5] A vehicle regenerative control method according to aspect 4, wherein increasing the required regenerative torque includes increasing an amount of increase in the required regenerative torque per unit time as the degree of decrease in the accelerator depression amount increases.

[0113] According to this method, the greater the decrease in accelerator operation amount, the greater the increase in required regenerative torque per unit time, making it possible to bring the braking feeling closer to the braking feeling when the engine brake is activated in an engine vehicle, making it easier to prevent discomfort for users who are accustomed to driving engine vehicles.

[0114] [Aspect 6] Determining the required regenerative torque based on the degree of decrease in the accelerator operation amount increasing the required regenerative torque over time based on the degree of decrease in the accelerator operation amount; When the required regenerative torque reaches a predetermined upper limit value, the required regenerative torque is maintained at the upper limit value; Determining whether a predetermined regeneration reduction condition is satisfied; and The vehicle regeneration control method according to any one of aspects 1 to 5, further comprising: reducing the required regeneration torque when it is determined that the regeneration reduction condition is satisfied.

[0115] According to the above method, since an upper limit value of the regenerative torque is set, it is possible to prevent the braking force due to the regenerative torque from becoming excessive.

[0116] [Aspect 7] 7. The vehicle regenerative control method according to aspect 6, wherein the upper limit value varies depending on a rotation speed of the electric motor.

[0117] According to the above method, the upper limit of the regenerative torque is changed according to the motor rotation speed, so that the regenerative torque of the electric motor can be limited to a range suitable for the rotation speed.

[0118] [Aspect 8] Determining the required regenerative torque based on the degree of decrease in the accelerator operation amount changing the required regenerative torque over time based on the degree of decrease in the accelerator operation amount; Determining whether a predetermined regeneration reduction condition is satisfied; and A regenerative control method for a vehicle described in any one of aspects 1 to 3, comprising: reducing the regenerative torque over time when it is determined that the regenerative reduction condition is satisfied after or during the process of changing the required regenerative torque based on the degree of reduction in the accelerator operation amount.

[0119] According to the above method, the regenerative torque decreases over time after it is determined that the regenerative reduction condition is satisfied, thereby reducing the shock to the vehicle body compared to when the regenerative torque is suddenly reduced.

[0120] [Aspect 9] A regenerative control method executed in a processing circuit of a vehicle having an electric motor as a drive source, comprising: Determining whether a regenerative control initiation condition that requires the electric motor to generate a regenerative torque is satisfied; and determining a required regenerative torque, which is the regenerative torque required of the electric motor, after it is determined that the start condition is satisfied; A regenerative control method for a vehicle, wherein an absolute value of the required regenerative torque determined during a predetermined period from the start of the regenerative control is greater than an absolute value of the required regenerative torque determined after the predetermined period has elapsed.

[0121] According to the above method, a relatively large regenerative torque can be applied for a predetermined period from the start of regenerative control, and a braking feeling that matches the user's intention to decelerate can be generated.

[0122] [Aspect 10] an accelerator operator operated by a user; Drive wheels and an electric motor as a drive source for driving the drive wheels; a processing circuit for controlling a regenerative torque of the electric motor that brakes the drive wheels; The processing circuitry includes: determining whether a regenerative control start condition that requests the electric motor to generate a regenerative torque is satisfied; A degree of decrease in accelerator operation amount over time before the start of the regenerative control is obtained; A saddle riding vehicle configured to determine a required regenerative torque, which is the regenerative torque required of the electric motor, based on the degree of decrease in the accelerator operation amount. [Explanation of symbols]

[0123] 1: Vehicle 2: Body 3a: Battery 6: Electric motor 21: Accelerator sensor 22: Rotational speed sensor 31: Controller

Claims

1. A regenerative control method executed in a processing circuit of a vehicle having an electric motor as a drive source, comprising: determining whether a regenerative control initiation condition that requests the electric motor to generate a regenerative torque is satisfied; Obtaining a degree of decrease in accelerator operation amount over time before the start of the regenerative control; and A regenerative control method for a vehicle comprising: determining a required regenerative torque, which is the regenerative torque required of the electric motor, based on the degree of decrease in the accelerator operation amount.

2. The vehicle regenerative control method according to claim 1 , wherein the step of determining the required regenerative torque based on the degree of decrease in the accelerator depression amount is performed for a predetermined period from the start of the regenerative control.

3. 3. The vehicle regenerative control method according to claim 1, wherein determining the required regenerative torque based on the degree of decrease in the accelerator operation amount includes increasing the required regenerative torque as the degree of decrease in the accelerator operation amount increases.

4. 3. The vehicle regenerative control method of claim 1, wherein determining the required regenerative torque based on the degree of decrease in the accelerator operation amount includes increasing the required regenerative torque over time from the start of the regenerative control to a point at which a predetermined condition is satisfied.

5. 5. The vehicle regenerative control method according to claim 4, wherein increasing the required regenerative torque includes increasing an increase amount of the required regenerative torque per unit time as the degree of decrease in the accelerator depression amount increases.

6. Determining the required regenerative torque based on the degree of decrease in the accelerator operation amount increasing the required regenerative torque over time based on the degree of decrease in the accelerator operation amount; When the required regenerative torque reaches a predetermined upper limit value, the required regenerative torque is maintained at the upper limit value; Determining whether a predetermined regeneration reduction condition is satisfied; and The method for controlling regeneration of a vehicle according to claim 1 , further comprising reducing the required regeneration torque when it is determined that the regeneration reduction condition is satisfied.

7. The vehicle regenerative control method according to claim 6 , wherein the upper limit value varies depending on a rotation speed of the electric motor.

8. Determining the required regenerative torque based on the degree of decrease in the accelerator operation amount changing the required regenerative torque over time based on the degree of decrease in the accelerator operation amount; Determining whether a predetermined regeneration reduction condition is satisfied; and 3. The vehicle regenerative control method of claim 1 or 2, further comprising: reducing the regenerative torque over time when it is determined that the regenerative reduction condition is satisfied after or during the change of the required regenerative torque based on the degree of reduction in the accelerator operation amount.

9. A regenerative control method executed in a processing circuit of a vehicle having an electric motor as a drive source, comprising: Determining whether a regenerative control initiation condition that requires the electric motor to generate a regenerative torque is satisfied; and determining a required regenerative torque, which is the regenerative torque required of the electric motor, after it is determined that the start condition is satisfied; A regenerative control method for a vehicle, wherein an absolute value of the required regenerative torque determined during a predetermined period from the start of the regenerative control is greater than an absolute value of the required regenerative torque determined after the predetermined period has elapsed.

10. an accelerator operator operated by a user; Drive wheels and an electric motor as a drive source for driving the drive wheels; a processing circuit for controlling a regenerative torque of the electric motor that brakes the drive wheels; The processing circuitry includes: determining whether a regenerative control start condition that requests the electric motor to generate a regenerative torque is satisfied; A degree of decrease in accelerator operation amount over time before the start of the regenerative control is obtained; A saddle riding vehicle configured to determine a required regenerative torque, which is the regenerative torque required of the electric motor, based on the degree of decrease in the accelerator operation amount.

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