On-vehicle control device

Abstract

To suppress frequent guiding given so as press a brake pedal when a regenerative brake force falls on the basis of the state of a power storage device.SOLUTION: When a regenerable torque obtained through regenerative driving of an electric motor becomes equal to or higher than a prescribed threshold value, prescribed notification is executed, a message about the execution of the prescribed notification is stored as history, and permitted maximum input power inputtable to a power storage device when the notification is executed is stored as control input power. If there is history of messaging about the execution of the prescribed notification, the notification is executed again when the regenerable torque is equal to or higher than the threshold value and when an absolute value of the permitted maximum input power is less than that of the control input power.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an in-vehicle control device, and more particularly to an in-vehicle control device mounted on an electric vehicle.

Background Art

[0002] Conventionally, as this type of in-vehicle control device, when the difference obtained by subtracting the regenerative braking amount calculated from the operation state of the accelerator pedal from the upper limit amount of regeneration calculated from the state of the battery becomes less than a predetermined amount, a guidance is proposed to prompt stepping on the brake pedal, such as "Please step on the brake" (see, for example, Patent Document 1). In this device, the discomfort of the driver associated with the pedal switching operation when the regenerative braking force cannot be obtained is suppressed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described device, when the regenerative braking force decreases based on the state of the battery, a guidance prompt to step on the brake pedal may be frequently given. Such frequent notification of the guidance causes annoyance to the driver and passengers.

[0005] The main object of the in-vehicle control device of the present disclosure is to suppress the frequent guidance to prompt stepping on the brake pedal when the regenerative braking force decreases based on the state of the power storage device.

Means for Solving the Problems

[0006] The in-vehicle control device of the present disclosure has taken the following means to achieve the above main object.

[0007] The in-vehicle control device of the present disclosure is an in-vehicle control device mounted on an electric vehicle including a traveling electric motor and a power storage device that exchanges power with the electric motor, when the regenerative torque obtained by the regenerative drive of the electric motor reaches a predetermined threshold or more, performs a predetermined notification and records that the predetermined notification has been performed, and stores the maximum allowable input power that can be input to the power storage device when the predetermined notification is performed as control input power, when there is a record that the predetermined notification has been performed, performs the predetermined notification again when the regenerative torque is equal to or more than the predetermined threshold and the absolute value of the maximum allowable input power is less than the absolute value of the control input power, characterized by this.

[0008] In the in-vehicle control device of the present disclosure, when the regenerative torque obtained by the regenerative drive of the electric motor reaches a predetermined threshold or more (the absolute value of the regenerative torque is less than or equal to the predetermined threshold), a predetermined notification is performed, and the fact that this predetermined notification has been performed is recorded. The maximum allowable input power that can be input to the power storage device when the predetermined notification is performed is stored as the control input power. Then, when there is a record of the predetermined notification having been performed, a new predetermined notification is performed when the regenerative torque is equal to or greater than the predetermined threshold and the absolute value of the maximum allowable input power is less than the absolute value of the control input power. That is, a new predetermined notification is performed when the regenerative torque is equal to or greater than the predetermined threshold (the absolute value of the regenerative torque is less than or equal to the predetermined threshold) and the maximum allowable input power is greater than the control input power (smaller in absolute value). Here, the output torque of the electric motor is a positive value, and the regenerative torque of the electric motor is a negative value. Also, the power output from the power storage device (discharge power) is a positive value, and the power input to the power storage device (charge power) is a negative value. In the present disclosure, when there is a record of the predetermined notification having been performed, a new predetermined notification is not performed even if the regenerative torque is equal to or greater than the predetermined threshold (the absolute value of the regenerative torque is less than or equal to the predetermined threshold) and the maximum allowable input power is less than the control input power (greater in absolute value). Thereby, it is possible to suppress the frequent performance of the predetermined notification when the regenerative braking force decreases based on the state of the power storage device.

[0009] In the in-vehicle control device of the present disclosure, the control input power may be upper-limited by the maximum allowable input power. That is, the control input power is replaced with the maximum allowable input power when it becomes smaller than the maximum allowable input power (the absolute value as a negative value becomes larger).

[0010] Note that, in the in-vehicle control device of the present disclosure, the predetermined notification includes a notification prompting the driver to perform a braking operation. Also, the predetermined threshold includes those set based on the shift position. Note that the record of the predetermined notification having been performed may be cleared when the system is started or when the absolute value of the maximum allowable input power of the power storage device becomes equal to or greater than a predetermined value.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0012] Next, embodiments of the present disclosure will be described. FIG. 1 is a configuration diagram showing an outline of the configuration of an electric vehicle 20 equipped with an in-vehicle control device as an embodiment of the present disclosure. The electric vehicle 20 includes a motor 22, an inverter 23, a battery 24, and an electronic control unit 30.

[0013] The motor 22 is configured as, for example, a synchronous generator motor. The rotor of the motor 22 is connected to a drive shaft 26 connected to drive wheels 28a and 28b via a differential gear 27. The motor 22 is driven by converting DC power from the battery 24 into three-phase AC power by the inverter 23 and applying the three-phase AC power by the inverter 23. Further, the motor 22 also functions as a generator by performing regenerative control, generates electricity using the rotational power of the drive shaft 26, and charges the battery 24 via the inverter 23. Note that the battery 24 is configured as a well-known lithium-ion secondary battery or nickel-metal hydride secondary battery.

[0014] The electronic control unit 30 is configured as a microcomputer centered around a CPU (not shown). Signals from various sensors are input to the electronic control unit 30 via input ports. For example, the electronic control unit 30 receives an ignition signal from the ignition switch 42, a shift position SP from the shift position sensor 44 that detects the position of the shift lever 43, an accelerator opening Acc from the accelerator pedal position sensor 46 that detects the depression amount of the accelerator pedal 45, a brake position BP from the brake pedal position sensor 48 that detects the depression amount of the brake pedal 47, a vehicle speed V from the vehicle speed sensor 49, etc. Further, the electronic control unit 30 receives a rotational position θ from a rotational position sensor (not shown) that detects the rotational position of the motor 22, a battery voltage Vb from a voltage sensor (not shown) attached to the output terminal of the battery 24, a battery current Ib from a current sensor (not shown) attached to the output terminal of the battery 24, etc. Additionally, the electronic control unit 30 also receives a switch signal SW from the changeover switch 50 that switches various displays of the display device 52. The shift position includes a parking position (P position), a neutral position (N position), a forward drive position (D position), a reverse drive position (R position), a brake position (B position), etc. The brake position (B position) is a position where the braking torque applied to the vehicle when the accelerator is off is smaller (larger in absolute value) than that in the forward drive position (D position). In the embodiment, the torque is set as a positive value when the motor 22 outputs a driving torque, and the torque when the motor 22 outputs a regenerative torque is set as a negative value. Also, the current and power when discharging from the battery 24 are set as positive values, and the current and power when charging the battery 24 are set as negative values.

[0015] The electronic control unit 30 outputs various control signals via the output ports. For example, the electronic control unit 30 outputs a display control signal to the display device 52. Further, the electronic control unit 30 outputs a switching control signal for switching a switching element (not shown) to the inverter 23 for driving the motor 22, a drive control signal to the system main relay 25 attached near the battery 24, and the like.

[0016] The electronic control unit 30 calculates the rotational speed Nm of the motor 22 based on the rotational position θ from a rotational position sensor (not shown) that detects the rotational position of the motor 22, and calculates the state of charge SOC of the battery 24 based on the battery voltage Vb and the battery current Ib. The state of charge SOC is the ratio of the remaining capacity to the total capacity of the battery 24. Further, the electronic control unit 30 also calculates the output limit Wout as the maximum allowable power that can be output from the battery 24 and the input limit Win as the maximum allowable power that can be input (chargeable) to the battery 24 based on the state of charge SOC of the battery 24, the temperature Tb of the battery 24, and the like.

[0017] Next, the operation of the electric vehicle 20 according to the embodiment, particularly the operation when executing a predetermined notification process for notifying the driver to step on the brake pedal 47 because the state of charge SOC of the battery 24 has increased and the input limit Win has increased (decreased in absolute value) will be described. FIG. 2 is a flowchart showing an example of the predetermined notification process executed by the electronic control unit 30. This predetermined notification process is repeatedly executed at predetermined time intervals.

[0018] When the specified notification process is executed, the electronic control unit 30 first inputs the shift position SP, the regenerative torque Tm by the motor 22, and the input limit Win of the battery 24 (step S100). The shift position SP is input as the one detected by the shift position sensor 44. The regenerative torque Tm is input as the one obtained based on the vehicle speed V and the input limit Win of the battery 24 (Tm = k·Win / V). Here, k is a conversion coefficient. The input limit Win of the battery 24 is input as the one calculated based on the state of charge SOC of the battery 24, the temperature Tb of the battery 24, etc.

[0019] Next, it is determined whether the regenerative torque Tm is greater than or equal to the threshold value Tref(SP) based on the shift position SP (step S110). The threshold value Tref(SP) is the braking torque (negative torque) to be applied to the vehicle when the accelerator is off, and a smaller value (larger in absolute value) is used when the shift position SP is in the B position than when the shift position SP is in the D position. Since the regenerative torque Tm is a negative value and the threshold value Tref(SP) is also a negative value, the process in step S110 is equivalent to the process of determining whether the absolute value of the regenerative torque Tm is less than or equal to the absolute value of the threshold value Tref(SP).

[0020] When it is determined in step S110 that the regenerative torque Tm is less than the threshold value Tref(SP), it is determined whether the notification history flag Frec has a value of 1 (step S170). When it is determined that the notification history flag Frec has a value of 0, this process ends. The notification history flag Frec is set by this specified notification process, and a value of 0 is set as the initial value at the time of system startup. Now, considering immediately after the system startup, it is determined in step S110 that the regenerative torque Tm is less than the threshold value Tref(SP), and it is determined in step S170 that the notification history flag Frec has a value of 0. Therefore, this specified notification process ends without doing anything in particular.

[0021] When it is determined in step S110 that the regenerative torque Tm is greater than or equal to the threshold value Tref(SP) (the absolute value of the regenerative torque Tm is less than or equal to the absolute value of the threshold value Tref(SP)), it is determined whether the notification history flag Frec has a value of 0 (step S120). Considering the case where it is determined for the first time after the system startup that the regenerative torque Tm is greater than or equal to the threshold value Tref(SP), since the notification history flag Frec has the initial value of 0, in step S120, it is determined that the notification history flag Frec has a value of 0. In this case, in order to indicate the history of the predetermined notification, the value 1 is set in the notification history flag Frec (step S130), and a predetermined notification is performed such as displaying on the display device 52 a message prompting the depression of the brake pedal 47 such as "The deceleration is decreasing. Please step on the brake pedal." (step S150), and the input limit Win of the battery 24 at that time is set to the control limit Winc (step S160).

[0022] Subsequently, it is determined whether the notification history flag Frec has a value of 1 (step S170). Considering immediately after the processing of steps S130, S150, and S160 is executed, in step S170, it is determined that the notification history flag Frec has a value of 1, and a minimum select process is performed to set the smaller one of the control limit Winc and the input limit Win to the new control limit Winc (step S180). Since the control limit Winc and the input limit Win are negative values, the processing in step S180 is a process of upper limit guarding the control limit Winc with the input limit Win.

[0023] Then, it is determined whether the input limit Win of the battery 24 is less than the predetermined value Wref (step S190). As the predetermined value Wref, a value of the input limit Win of the battery 24 that does not need to consider the decrease in the deceleration can be used. That is, step S190 determines whether the state such as the state of charge SOC of the battery 24 is in a state where the decrease in the deceleration does not need to be considered. When it is determined that the input limit Win of the battery 24 is less than the predetermined value Wref, the notification history flag Frec is reset to the value 0 (step S200), and this process ends.

[0024] When it is determined in step S120 that the notification history flag Frec has a value of 1 (there is a notification history), it is determined whether the absolute value of the input limit Win of the battery 24 is less than the absolute value of the control limit Winc (whether the input limit Win is greater than the control limit Winc) (step S140). When it is determined that the absolute value of the input limit Win of the battery 24 is less than the absolute value of the control limit Winc (the input limit Win is greater than the control limit Winc), a predetermined notification is performed (step S150), the input limit Win at that time is set to the control limit Winc (step S160), the processing after step S170 is executed, and this processing is terminated.

[0025] When it is determined in step S140 that the absolute value of the input limit Win of the battery 24 is greater than or equal to the absolute value of the control limit Winc (the input limit Win is less than or equal to the control limit Winc), the processing after step S170 is executed without performing a predetermined notification, and this processing is terminated.

[0026] FIG. 3 is an explanatory diagram showing an example of temporal changes in a predetermined notification, a notification history flag Frec, a regenerable torque Tm, and a control restriction Winc when the predetermined notification process of the embodiment is executed. The broken line in the column of the regenerable torque Tm indicates a threshold value Tref(SP), and the broken line in the column of the control restriction Winc indicates an input restriction Win of the battery 24. When the regenerable torque Tm becomes equal to or greater than the threshold value Tref(SP) at time T1, a predetermined notification is performed for a certain period until time T2, the value 1 is set in the notification history flag Frec, and the input restriction Win is set in the control restriction Winc. When the regenerable torque Tm again becomes equal to or greater than the threshold value Tref(SP) at time T3, since the notification history flag Frec has the value 1, a determination is made as to whether or not the absolute value of the input restriction Win of the battery 24 is smaller than the absolute value of the control restriction Winc. However, since the input restriction Win and the control restriction Winc are the same, a negative determination is made and no further predetermined notification is performed. From time T4 to time T5, an upper limit guard is performed by the input restriction Win of the control restriction Winc. When the regenerable torque Tm becomes equal to or greater than the threshold value Tref(SP) at time T6, since the notification history flag Frec has the value 1, a determination is made as to whether or not the absolute value of the input restriction Win of the battery 24 is smaller than the absolute value of the control restriction Winc. However, since the absolute value of the input restriction Win is smaller than the absolute value of the control restriction Winc, an affirmative determination is made, and a further predetermined notification is performed until time T7. The value 1 is set in the notification history flag Frec, and the input restriction Win is set in the control restriction Winc.

[0027] In the electronic control unit 30 (in-vehicle control device) mounted on the electric vehicle 20 of the embodiment described above, when the regenerative torque Tm becomes equal to or greater than the threshold value Tref(SP), a predetermined notification is performed to prompt the depression of the brake pedal 47 for a certain period of time. At the same time, the value 1 is set in the notification history flag Frec, and the input limit Win is set in the control limit Winc. Thereafter, when the regenerative torque Tm becomes equal to or greater than the threshold value Tref(SP) while the notification history flag Frec has the value 1, if the absolute value of the input limit Win of the battery 24 is smaller than the absolute value of the control limit Winc, a predetermined notification is performed to prompt the depression of the brake pedal 47 for a certain period of time. However, if the absolute value of the input limit Win of the battery 24 is equal to or greater than the absolute value of the control limit Winc, no predetermined notification is performed. Thereby, it is possible to suppress the frequent performance of the notification (predetermined notification) that prompts the depression of the brake pedal 47 when the regenerative braking force decreases based on the state of the battery 24.

[0028] In the electric vehicle 20 of the embodiment, it is assumed that the motor 22, the inverter 23, and the battery 24 are provided. However, as long as the battery is charged with the power obtained by driving the motor regeneratively, any type of electric vehicle, for example, a fuel cell vehicle or a hybrid vehicle, may be used.

[0029] The correspondence between the main elements of the embodiment and the main elements of the invention described in the section of means for solving the problems will be described. In the embodiment, the motor 22 corresponds to the "electric motor", the battery 24 corresponds to the "power storage device", and the electronic control unit 30 corresponds to the "in-vehicle control device".

[0030] Note that the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems is an example for specifically explaining the mode for carrying out the invention described in the column of means for solving the problems in the embodiment. Therefore, it does not limit the elements of the invention described in the column of means for solving the problems. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description in that column, and the embodiment is merely a specific example of the invention described in the column of means for solving the problems.

[0031] As described above, the present disclosure has been described using embodiments. However, the present disclosure is not limited to such embodiments, and it goes without saying that the present disclosure can be implemented in various forms without departing from the gist of the present disclosure.

Industrial Applicability

[0032] The present disclosure can be used in the manufacturing industry of in-vehicle control devices and the like.

Explanation of Reference Numerals

[0033] 20 Electric vehicle, 22 Motor, 23 Inverter, 24 Battery, 25 Drive shaft, 26 Differential gear, 28a, 28b Drive wheels, 30 Electronic control unit, 42 Ignition switch, 43 Shift lever, 44 Shift position sensor, 45 Accelerator pedal, 46 Accelerator pedal position sensor, 47 Brake pedal, 48 Brake pedal position sensor, 49 Vehicle speed sensor, 50 Changeover switch, 52 Display device.

Claims

1. An on-board control device mounted on an electric vehicle including an electric motor for driving the vehicle and an electricity storage device for exchanging electric power with the electric motor, when a regenerative torque obtained by regenerative driving of the electric motor reaches or exceeds a predetermined threshold, a predetermined notification is issued, a history is recorded to the effect that the predetermined notification has been issued, and a maximum allowable input power that can be input to the power storage device at the time when the predetermined notification was issued is stored as a control input power; When there is a history of the predetermined notification being performed, the predetermined notification is performed again when the regenerative torque is equal to or greater than the predetermined threshold value and the absolute value of the maximum allowable input power is less than the absolute value of the control input power.

2. An in-vehicle control device comprising:

2. 2. The vehicle-mounted control device according to claim 1, The control input power is upper-limit-guarded by the maximum allowable input power. In-vehicle control device.

3. 3. The vehicle-mounted control device according to claim 1, The predetermined threshold value is set based on a shift position. In-vehicle control device.

4. 3. The vehicle control device according to claim 1, The predetermined notification is a notification that prompts the driver to perform a brake operation. In-vehicle control device.

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