Hybrid vehicle

Abstract

To provide a technique capable of appropriately controlling charging / discharging of a battery when a hybrid vehicle circulates on a circuit.SOLUTION: This hybrid vehicle comprises: a motor; a battery connected to the motor and charged / discharged with the motor; and a control device that discharges the battery in accordance with an accelerator operation by a user, and discharges the battery in accordance with a brake operation by the user. The control device is configured to be able to execute a circuit mode for circulating the hybrid vehicle on a circuit. In the circuit mode, the control device has a process for calculating an integrated value of discharge power discharged from the battery in accordance with the accelerator operation and an integrated value of charge power charged from the battery in accordance with the brake operation during one circulation of the hybrid vehicle on the circuit, and a process for correcting a relationship between the accelerator operation and the discharge power accordingly discharged from the battery on the basis of the integrated value of discharge power and the integrated value of charge power.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The technology disclosed in this specification relates to hybrid vehicles. [Background technology]

[0002] Patent Document 1 discloses a method for controlling the state of charge of a battery in a hybrid vehicle. In this technology, an initial target value of the state of charge of the battery is set, and an average charge / discharge amount of the battery determined by the running state of the vehicle is calculated. Then, an SOC correction amount for correcting the initial target value is calculated based on the average charge / discharge amount. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-152420 A Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 does not assume the case where a hybrid vehicle runs around a circuit. When a hybrid vehicle runs around a circuit, the acceleration and deceleration of the hybrid vehicle are relatively large. When the acceleration of the hybrid vehicle is large, the discharge power from the battery is large. On the other hand, when the deceleration of the hybrid vehicle is large, the regenerative power generated during deceleration is large, but if the regenerative power is too large, it is not possible to supply all of it as charging power to the battery. For this reason, the amount of charge (amount of charging power) to the battery due to deceleration is usually smaller than the amount of discharge (amount of discharging power) of the battery due to acceleration. That is, when a hybrid vehicle runs around a circuit, the amount of discharge is likely to be excessive compared to the amount of charge, and there is a risk that the SOC (State Of Charge) of the battery will decrease early. This specification provides a technology that can appropriately control the charging and discharging of the battery when a hybrid vehicle runs around a circuit. [Means for solving the problem]

[0005] The hybrid vehicle disclosed in this specification comprises a motor that drives and regeneratively brakes the wheels, a battery connected to the motor and charged and discharged between the motor and the battery, and a control device that discharges the battery in response to accelerator operation by a user and charges the battery in response to brake operation by the user, the control device being configured to be able to execute a circuit mode in which the hybrid vehicle travels around a circuit, the circuit mode including a process for calculating an integrated value of discharge power discharged from the battery in response to accelerator operation and an integrated value of charge power charged to the battery in response to brake operation while the hybrid vehicle travels around the circuit, and a process for correcting the relationship between the accelerator operation and the discharge power that discharges the battery in response thereto, based on the integrated value of discharge power and the integrated value of charge power.

[0006] According to the above configuration, the hybrid vehicle calculates an integrated value of the discharge power discharged from the battery in response to the accelerator operation (i.e., the discharge amount) and an integrated value of the charging power charged to the battery in response to the brake operation while traveling around the circuit. The hybrid vehicle then corrects the relationship between the accelerator operation and the corresponding discharge power that discharges the battery based on the integrated value of the discharge power and the integrated value of the charging power. In this way, by correcting the relationship between the accelerator operation and the corresponding discharge power that discharges the battery, the charging and discharging of the battery can be appropriately controlled when the hybrid vehicle travels around the circuit.

[0007] In one embodiment of the present technology, in the process of correcting the relationship, the relationship may be corrected such that the integrated value of the discharge power and the integrated value of the charge power match in each lap of the circuit.

[0008] In the above-described embodiment, in the process of correcting the relationship, the relationship may be corrected using a ratio of the integrated value of the charging power to the integrated value of the discharging power.

[0009] In one embodiment of the present technology, when the number of laps of the circuit is predetermined, the process of correcting the relationship may correct the relationship so that the SOC of the battery falls to an allowable lower limit value after the predetermined number of laps are completed. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of a hybrid vehicle equipped with a control device; [Diagram 2] 4 is a time chart of the first embodiment. [Diagram 3] 6 is a time chart of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] (First Example) 1, a hybrid vehicle 10 of the embodiment includes a vehicle body 12, and a pair of drive wheels 14 and a pair of rolling wheels 16 that are rotatably supported on the vehicle body 12. The pair of drive wheels 14 are connected to an output shaft 20 via a differential gear 18.

[0012] The hybrid vehicle 10 further includes an engine 22 and a motor generator 24. Hereinafter, the motor generator 24 will be simply referred to as the "motor 24." The engine 22 is connected to the output shaft 20 and the motor 24 via a planetary gear mechanism 28. The planetary gear mechanism 28 is a type of power distribution mechanism, and distributes the power output by the engine 22 to the output shaft 20 and the motor 24. The motor 24 is a three-phase motor having three phases, U-phase, V-phase, and W-phase, and drives and regeneratively brakes the drive wheels 14.

[0013] The hybrid vehicle 10 further includes a power conversion circuit 30 and a battery 38. The battery 38 is electrically connected to the motor 24 via the power conversion circuit 30, and is charged and discharged between the battery 38 and the motor 24. The battery 38 is a secondary battery, for example a lithium ion battery.

[0014] The power conversion circuit 30 includes a DC-DC converter 32 and an inverter 34. The battery 38 is connected to the inverter 34 via the DC-DC converter 32. The DC-DC converter 32 can step up the DC voltage from the battery 38 and supply it to the inverter 34. The inverter 34 can convert the DC power from the DC-DC converter 32 into AC power and supply it to the motor 24. The inverter 34 can also convert the AC power from the motor 24 into DC power and supply it to the DC-DC converter 32. The DC-DC converter 32 can step down the DC power from the inverter 34 and supply it to the battery 38.

[0015] The hybrid vehicle 10 further includes a hybrid control unit (HV-ECU) 40, a motor control unit 41 (MG-ECU), and an engine control unit 42 (ENG-ECU).

[0016] The hybrid control unit 40 is a higher-level control unit that is communicatively connected to the motor control unit 41 and the engine control unit 42 and issues operation commands to these units. The hybrid control unit 40 controls each device provided in the hybrid vehicle 10 according to a control program stored in a storage unit (not shown). For example, a user inputs instructions to the hybrid vehicle 10 by operating various operation units (not shown), such as an accelerator pedal, a brake pedal, and a shift lever. User operation information is transmitted to the hybrid control unit 40. The hybrid control unit 40 generates a motor operation command MC for the motor 24 and an engine operation command EC for the engine 22, based on the operation information.

[0017] The motor control unit 41 is a unit that controls the operation of the motor 24 and the battery 38 based on the motor operation command MC received from the hybrid control unit 40. The motor control unit 41 is communicatively connected to the power conversion circuit 30, and controls the operation of the DC-DC converter 32, the inverter 34, and the battery 38. Specifically, the motor control unit 41 discharges the battery 38 in response to an accelerator operation by the user, and charges the battery 38 in response to a brake operation by the user.

[0018] The engine control unit 42 is a unit that controls the operation of the engine 22 based on an engine operation command EC received from the hybrid control unit 40 .

[0019] The hybrid control unit 40 is also configured to be able to execute a circuit mode for the hybrid vehicle 10 to travel around a circuit. The circuit mode is a mode for improving the running performance of the hybrid vehicle 10 when it travels around a closed course such as a circuit.

[0020] When the hybrid vehicle 10 travels on a circuit, the traveling speed is likely to be higher than when the hybrid vehicle 10 travels on a general road, and the acceleration and deceleration are likely to be larger accordingly. When the hybrid vehicle 10 accelerates more, the discharge power from the battery 38 is large. On the other hand, when the hybrid vehicle 10 decelerates more, the regenerative power generated by the motor 24 during deceleration is large. However, if the regenerative power is too large, it is not possible to supply all of it as charging power to the battery 38 due to the tolerance of the battery 38 for accepting electric power. Therefore, the amount of charge to the battery 38 due to deceleration is smaller than the amount of discharge from the battery 38 due to acceleration. That is, when the hybrid vehicle 10 travels on a circuit, the amount of discharge is likely to be excessive compared to the amount of charge, and the remaining capacity (hereinafter referred to as "SOC") of the battery 38 is likely to decrease. As a result, the speed of the hybrid vehicle 10 may be restricted by prohibiting or restricting discharge from the battery 38 or increasing the proportion of the output of the engine 22 distributed to the motor 24. By limiting the speed of the hybrid vehicle 10, the time required to complete each lap when traveling around a circuit is reduced.

[0021] Therefore, in the circuit mode, the hybrid vehicle 10 of this embodiment executes a process for suppressing the occurrence of the above-mentioned events due to a drop in the SOC of the battery 38. Specifically, the hybrid vehicle 10 executes a process for calculating an integrated value of the discharge power and the charge power while going around the circuit, and a process for correcting the relationship between the accelerator operation and the discharge power that discharges the battery 38 accordingly, based on the calculated integrated value. Each of the above processes will be described below with reference to FIG. 2.

[0022] As shown in Fig. 2, at time t0, the hybrid vehicle 10 starts traveling around the circuit by receiving an accelerator operation from the user. At this time, the hybrid vehicle 10 determines that traveling around the circuit has started. Specifically, when the hybrid vehicle 10 is stopped and set to the circuit mode, the hybrid vehicle 10 determines that traveling around the circuit has started by receiving an accelerator operation. The hybrid vehicle 10 then stores location information (e.g., GPS information) indicating the location of the hybrid vehicle 10 when traveling around the circuit started. The location information is used to determine the end of traveling around the circuit.

[0023] The hybrid vehicle 10 travels around the circuit at a speed desired by the user through repeated accelerator and brake operations by the user. In particular, the hybrid vehicle 10 discharges discharge power to the battery 38 according to the accelerator operation in accordance with an output map Wout that stores the magnitude of the accelerator operation (i.e., the amount of depression of the accelerator pedal) in association with the magnitude of the discharge power of the battery 38 at that time.

[0024] For example, as shown in Fig. 2, for a while after the start of traveling (i.e., time t0), the hybrid vehicle 10 is accelerated from a stop, so the rate of acceleration is high. That is, the discharge power (amount discharged per unit time (e.g., 1 second)) from the battery 38 is also large. The amount of discharge of the battery 38 during this period is calculated as (Pb_a1 x time_a1). Here, Pb_a1 represents the magnitude of the discharge power of the battery 38, and time_a1 represents the time during which the discharge power of the magnitude of Pb_a1 is being discharged.

[0025] Thereafter, when the hybrid vehicle 10 accelerates to a predetermined speed, the user eases up on the accelerator pedal. As a result, the discharged power from the battery 38 decreases. The discharged amount of the battery 38 during this period is calculated as (Pb_a2×time_a2).

[0026] Thereafter, the hybrid vehicle 10 receives a brake operation from the user. In this case, part of the regenerative power of the motor 24 is supplied to the battery 38 as charging power. The charging amount at this time is calculated as (Pb_d1×time_d1). Here, Pb_d1 represents the magnitude of the charging power supplied to the battery 38 (the charging amount per unit time), and time_d1 represents the time during which the charging power of the magnitude of Pb_d1 is supplied to the battery 38.

[0027] The hybrid vehicle 10 travels around the circuit while repeatedly charging and discharging the battery 38 as described above, and completes one lap around the circuit at time t1. The hybrid vehicle 10 determines that one lap around the circuit has been completed when it reaches a position indicated by the position information stored at the start of one lap around the circuit. In a modified example, the hybrid vehicle 10 may determine that one lap around the circuit has been completed in response to an operation by the user.

[0028] While the hybrid vehicle 10 goes around the circuit, it calculates an integrated value X of the discharged power (i.e., the discharged amount) and an integrated value Y of the charged power (i.e., the charged amount). There is no particular limitation on the specific calculation method. However, these integrated values ​​X and Y can be expressed by the following formula 1.

[0029]

number

[0030] Then, when one lap of the circuit is completed, the hybrid vehicle 10 executes a process to correct the relationship between the accelerator operation and the corresponding discharge power for discharging the battery 38, based on the integrated value X of the discharge power and the integrated value Y of the charge power during that one lap. Specifically, the output map Wout_new to be used in the next lap of the circuit is calculated by the formula represented by the following equation 2.

[0031]

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[0032] As shown in the formula 2, the hybrid vehicle 10 uses the ratio of the integrated value Y of the charging power to the integrated value X of the discharging power to correct the relationship (i.e., the output map) between the accelerator operation and the discharge power that discharges the battery 38 accordingly so that they match. The hybrid vehicle 10 uses the calculated output map Wout_new when traveling the next lap (i.e., the second lap) of the circuit. Note that in this embodiment, a situation is assumed in which the integrated value X of the discharging power before one lap is greater than the integrated value Y of the charging power before one lap (X>Y). Therefore, since (Y / X) in the formula 2 is a value less than 1, even in a situation where the same accelerator operation is performed, the output of the hybrid vehicle 10 in the second lap (i.e., the speed of the hybrid vehicle 10) is smaller than the output of the hybrid vehicle 10 in the first lap. Therefore, even in a situation where the same accelerator operation is performed, the magnitude of the discharge power of the battery 38 in the second lap is smaller than the magnitude of the discharge power of the battery 38 in the first lap.

[0033] At time t1, the hybrid vehicle 10 starts traveling around the circuit for the second time. Since the hybrid vehicle 10 is traveling around the circuit, the timing of the accelerator operation and the brake operation by the user during the second lap is generally the same as the timing of the accelerator operation and the brake operation by the user during the first lap. Nevertheless, as shown by the solid line after time t1 in FIG. 2, in a situation where the power of the battery 38 is used, the magnitude of the discharge power of the battery 38 becomes smaller than the discharge power of the battery 38 at the same place before the first lap. As a result, the second lap can be completed at time t2 without the SOC of the battery 38 decreasing excessively (i.e., without reaching the control lower limit SOC). That is, the hybrid vehicle 10 can travel around the circuit for the second time T2'=t2-t1. In this way, by correcting the relationship between the accelerator operation and the discharge power that discharges the battery 38 accordingly (i.e., the output map), the charge and discharge of the battery 38 can be appropriately controlled when the hybrid vehicle 10 travels around the circuit. In particular, since the output map is corrected using information from one lap ago, the hybrid vehicle 10 can appropriately control the charging and discharging of the battery 38 without having to previously store an output map according to the circuit.

[0034] During the second lap, the magnitude of the discharge power and the magnitude of the charge power of the battery 38 are accumulated, as in the first lap. Then, at the end of the second lap, the process of correcting the output map is executed again using the accumulated values ​​X and Y in the second lap. As a result, the output map corrected again is used in the third lap. By executing such a process in each lap, the error in the output map becomes smaller with each lap. Therefore, the variation in the time required to travel one lap becomes smaller between each lap.

[0035] Here, a comparative example is assumed in which the output map is not corrected as described above (see the broken line in FIG. 2). In this comparative example, the discharge power of the battery 38 is the same as that of the first lap. In this comparative example, the SOC of the battery 38 reaches the control lower limit SOC at time t3. When the SOC of the battery 38 reaches the control lower limit SOC, the discharge from the battery 38 is prohibited or limited, or the ratio of the output of the engine 22 distributed to the motor 24 is increased, thereby limiting the speed of the hybrid vehicle 10. For this reason, the second lap ends at time t4 in the comparative example, but the time required for the running is T2=t4-t1, which is longer than the time T2' in this embodiment. Therefore, according to the configuration of this embodiment, the time required for each lap when running around the circuit is shorter than that in the comparative example.

[0036] (Second Example) Next, a second embodiment will be described. In the hybrid vehicle 10 of the second embodiment, when the number of laps of the circuit is preset, the output map is corrected so that the SOC of the battery 38 decreases to the control lower limit value S2 after the preset number of laps is completed.

[0037] 3, the hybrid vehicle 10 first travels around the circuit (performs a test run) between time t10 and time t11. This test run is the same as the first run in the first embodiment. After the test run is completed, the battery 38 of the hybrid vehicle 10 is fully charged, and at time t12, the SOC of the battery 38 increases to the control upper limit value S1.

[0038] Further, the hybrid vehicle 10 calculates an output map Wout_new2 to be used throughout the entire circuit run based on the integrated value X of the discharged power and the integrated value Y of the charged power during the test run, using the formula represented by the following equation 3.

[0039]

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[0040] In the above formula 3, a represents the current battery capacity, and n represents the predetermined number of laps. Here, the current battery capacity a means a ratio corresponding to the current SOC of the battery 38 when the SOC of the battery 38 is the control upper limit value S1 and is 1 when the SOC of the battery 38 is the control lower limit value S2, and is a value between 0 and 1. That is, if the current SOC of the battery 38 is S, it is expressed as a=(S-S2) / (S1-S2). The term "a×(S1-S2) / n" in formula 3 means the SOC of the battery 38 that decreases per lap. Therefore, after the completion of n laps, the SOC of the battery 38 decreases by a×(S1-S2)=(S-S2). Therefore, after the completion of n laps, the SOC of the battery 38 becomes S-(S-S2)=S2 (i.e., the control lower limit value). In this way, according to the output map Wout_new2 expressed by the formula 3, the hybrid vehicle 10 controls the discharge of the battery 38 so that the SOC of the battery 38 becomes the control lower limit value S2 when the hybrid vehicle 10 has completed n laps of the circuit using the accelerator operation or the like similar to the test run. Note that the value of the output map Wout_new2 in the second embodiment is greater than that of the output map Wout_new in the first embodiment, and therefore the time T2"=t13-t12 for each lap in the second embodiment is less than the time T2' for each lap in the first embodiment.

[0041] In this way, according to the configuration of the second embodiment, when the number of laps of a circuit is preset, the discharge of the battery 38 can be controlled so that the SOC of the battery 38 becomes the control lower limit value S2 after the preset number of laps is completed. That is, when the hybrid vehicle 10 runs around a circuit, the charging and discharging of the battery 38 can be appropriately controlled. In particular, with the configuration of the second embodiment, the time required to run the preset number of laps can be minimized. [Explanation of symbols]

[0042] 10: hybrid vehicle, 12: vehicle body, 14: drive wheels, 16: rolling wheels, 18: differential gear, 20: output shaft, 22: engine, 24: motor generator, 28: planetary gear mechanism, 30: power conversion device, 32: DC-DC converter, 34: inverter, 38: battery, 40: hybrid control unit, 41: motor control unit, 42: engine control unit

Claims

[Claim 1] A hybrid vehicle, A motor for driving and regenerative braking the wheels; a battery connected to the motor and charged and discharged between the battery and the motor; a control device that discharges the battery in response to an accelerator operation by a user and charges the battery in response to a brake operation by the user; Equipped with the control device is configured to be able to execute a circuit mode for causing the hybrid vehicle to travel around a circuit, The circuit mode is calculating an integrated value of discharged power discharged from the battery in response to the accelerator operation and an integrated value of charged power charged to the battery in response to the brake operation while the hybrid vehicle goes around the circuit; and correcting a relationship between the accelerator operation and a discharge power for discharging the battery in response thereto, based on the integrated value of the discharge power and the integrated value of the charge power. Hybrid car.

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