Vehicle control device

Abstract

To make it possible to cope with a failure in an electric power supply for supplying electric power to an auxiliary battery while reducing the possibility of giving inconvenience to a user of a vehicle.SOLUTION: A vehicular control device controls a vehicle which includes an auxiliary battery for driving an auxiliary machine. The control device calculates a travelable time or travelable distance of the vehicle from the remaining amount of energy in a power source. The control device calculates a sustainable time or a sustainable distance allowing a state in which a remaining amount in the auxiliary battery is equal to or more than a prescribed value to be sustained. The control device restricts the operation of the auxiliary machine so that the travelable time becomes longer than the sustainable time when the sustainable time is shorter than the travelable time, or so that the travelable distance becomes longer than the sustainable distance when the sustainable distance is shorter than the travelable distance.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a control device for a vehicle including an accessory battery for driving accessories.

Background Art

[0002] Patent Document 1 discloses an electric vehicle. This electric vehicle includes a voltage converter that converts part of the charge / discharge power of a high-voltage battery used as a driving power source of the vehicle and supplies driving power to electrical components, an accessory motor that is driven by the charge / discharge power of the high-voltage battery to operate a compressor of an air conditioner, and a blower motor for the air conditioner that operates by receiving driving power from the voltage converter. Moreover, when the voltage converter fails, a suppression signal is output to prohibit the operation of the air conditioner.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a power source that supplies power to an accessory battery for driving accessories fails, even if there is a low possibility that the remaining amount of the accessory battery will be insufficient without restricting the operation of the accessories, if the operation of the accessories is generally restricted, there is a risk of inconveniencing the user of the vehicle.

[0005] The present disclosure has been made in view of the above problems, and an object thereof is to provide a control device for a vehicle that can cope with a failure of a power source that supplies power to an accessory battery while reducing the possibility of inconveniencing the user of the vehicle.

Means for Solving the Problems

[0006] The vehicle control device according to the present disclosure controls a vehicle including an auxiliary battery for driving auxiliary machines. The control device calculates the remaining travelable time or travelable distance of the vehicle from the remaining energy of the power source. The control device calculates the maintainable time or maintainable distance in a state where the remaining amount of the auxiliary battery is equal to or more than a predetermined value. Then, when the maintainable time is shorter than the travelable time is travelable time so as to be or, when the maintainable distance is shorter than the travelable distance, the maintainable distance is travelable distance so as to be is used to limit the operation of the auxiliary machine.

Advantages of the Invention

[0007] According to the vehicle control device of the present disclosure, it becomes possible to cope with a failure of the power source that supplies power to the auxiliary battery while reducing the possibility of inconveniencing the vehicle user.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0009] 1. Configuration of the Vehicle The vehicle according to the present embodiment is an electric vehicle including an electric motor that drives wheels, and includes a main battery that supplies power to the electric motor and an auxiliary battery that drives various auxiliary machines mounted on the vehicle. The vehicle is, for example, a hybrid electric vehicle (HEV), but may be, for example, a battery electric vehicle (BEV) or a fuel cell electric vehicle (FCEV).

[0010] The vehicle has a power source (hereinafter also referred to as "power source for auxiliary equipment") that supplies power to the auxiliary battery, and is configured as follows, for example. That is, as a component that constitutes the power source, the vehicle has an alternator that is driven and rotated by an internal combustion engine. Also, as a component that constitutes the power source, the vehicle has a DC / DC converter that steps down the power of the main battery (high-voltage battery) and supplies it to the auxiliary battery (low-voltage battery).

[0011] The vehicle is equipped with a control device that controls the vehicle. The control device includes one or more electronic control units (ECUs) each having a processor and a storage device. The storage device stores various data including maps used for various controls of the vehicle, and various control programs. The processor reads out and executes the control programs from the storage device, thereby realizing various processes by the ECU for the above-mentioned various controls.

[0012] The control device is also configured to be capable of detecting the remaining charge and voltage of the auxiliary battery. Furthermore, the control device is configured to be capable of controlling the supply / cut-off of power to various auxiliary devices. The vehicle is also equipped with a sensor (e.g., a camera) that acquires information about the vehicle's surroundings (e.g., information about other vehicles and obstacles around the vehicle), a receiver that acquires traffic information, and a device that stores and acquires map information. Furthermore, the vehicle is equipped with a display device that can notify the driver of various information.

[0013] 2.Handling of control devices when auxiliary power supply fails If the power supply for the accessories fails (more specifically, if power supply components such as the above-mentioned alternator and DC / DC converter fail), power to the various accessories will be supplied only from the auxiliary battery. For this reason, if a lot of power is used to drive the accessories, there is a high possibility that the auxiliary battery will run out of charge faster than the main battery. If the auxiliary battery's charge decreases, the accessories will no longer operate normally. For this reason, even if there is still charge remaining in the main battery, a decrease in the auxiliary battery's charge can hinder smooth vehicle driving.

[0014] Therefore, when a failure occurs in the power supply for auxiliary equipment, it is conceivable to limit the operation of the auxiliary equipment. On the other hand, if the operation of the auxiliary equipment is unconditionally restricted even though the remaining amount of the auxiliary battery is unlikely to run out, it may cause inconvenience to the vehicle user.

[0015] FIGS. 1 to 3 are flowcharts showing the processes executed when a failure occurs in the power supply for auxiliary equipment in the embodiment. In view of the above problems, in this embodiment, the control device (the processor of the ECU) executes the process shown in FIG. 1. Further, the control device may execute the processes shown in FIGS. 2 and 3 respectively in association with the process shown in FIG. 1. As a premise, it is assumed that the control device is configured to be able to detect a failure in the power supply for auxiliary equipment.

[0016] Here, various auxiliary equipment mounted on the vehicle has various roles. Specifically, as an example, various auxiliary equipment can be classified into entertainment-related auxiliary equipment A such as audio, comfort-related auxiliary equipment B such as air conditioner, driving support-related auxiliary equipment C such as cruise control, preventive safety-related auxiliary equipment D such as automatic brake, and vehicle driving-related auxiliary equipment E such as electric power steering. Among such various auxiliary equipment, there are those that can be powered off without problems (auxiliary equipment A), those that should not be powered off if possible (auxiliary equipment B to D), and those that cannot be powered off (auxiliary equipment E). In addition, unlike the shortage of power of the main battery for vehicle driving, in the case of the auxiliary battery, the relationship between the remaining battery amount, the events that occur, and the countermeasures to be taken is difficult for the driver to understand.

[0017] Therefore, in order to enable driving while maximizing comfort and safety in the event of a power failure of the auxiliary machine, according to the process shown in FIG. 1, the operation of the auxiliary machine is restricted so that the "sustainable time T1" is equal to or greater than the "drivable time T2" while minimizing the interruption of the power supply for the auxiliary machine. The power cut-off conditions for the various auxiliary machines A to D classified as described above are determined, for example, in consideration of the behavior of the vehicle and the impact on the driver, and the details will be described later with reference to FIG. 1. The auxiliary machine E related to vehicle driving is not cut off. Additionally, the control of the "power supply for the auxiliary machine" related to the process shown in FIG. 1 may be a "decrease" in the power supplied from the power supply to the auxiliary machine instead of the "cut-off" of the power supply described below.

[0018] The sustainable time T1 is the time that the remaining amount of the auxiliary battery can be maintained above a predetermined value. The control device calculates the sustainable time T1 from the remaining amount of the auxiliary battery. The drivable time T2 is the time that the vehicle can drive. The control device calculates the drivable time T2 from the remaining energy (e.g., at least one of the remaining fuel and the remaining main battery) of the vehicle's power source (e.g., the above-mentioned electric motor and internal combustion engine).

[0019] Note that the control device may calculate the "sustainable distance (the driving distance that can maintain the remaining amount of the auxiliary battery above a predetermined value)" from the remaining amount of the auxiliary battery instead of the sustainable time T1, and calculate the "drivable distance (the distance that the vehicle can travel)" from the remaining energy instead of the drivable time T2, and then compare these distances. In the case of an FCEV vehicle, the remaining hydrogen amount is included in the remaining energy.

[0020] Specifically, in FIG. 1, when the control device detects a failure of the power supply for the auxiliary machine, it proceeds to step S100 and cuts off the power supply for the entertainment-related auxiliary machine A. In this way, the power cut-off of the auxiliary machine A is immediately executed upon detecting a failure of the power supply for the auxiliary machine without comparing the above times T1 and T2.

[0021] Next, in step S102, the control device determines whether the sustainable time T1 is greater than or equal to the travelable time T2. As a result, if this determination result is Yes (T1≥T2), the process proceeds to the return. On the other hand, if the determination result is No (T1<T2), the process proceeds to step S104.

[0022] In step S104, the control device determines whether the sustainable time T1 is shorter than the predetermined time T1th1 or the travelable time T2 is shorter than the predetermined time T2th1. As a result, if this determination result is Yes, the control device shuts off the power of the comfort-related auxiliary machine B in step S106. Next, in step S108, if the sustainable time T1 is greater than or equal to the travelable time T2, the process proceeds to the return, and if the sustainable time T1 is shorter than the travelable time T2, the process proceeds to step S110. Also, even if the determination result in step S104 is No (T1≥T1th1 and T2≥T2th1), the process proceeds to step S110.

[0023] When the vehicle running time is long, the comfort of the vehicle also affects the driver's condition. For this reason, as shown in FIG. 1, when the sustainable time T1 is shorter than the predetermined time T1th1 or the travelable time T2 is shorter than the predetermined time T2th1, the power of the auxiliary machine B is quickly shut off, but when the sustainable time T1 is greater than or equal to the predetermined time T1th1 (that is, there is a margin in the sustainable time T1) and the travelable time T2 is greater than or equal to the predetermined time T2th1, the power of the auxiliary machine B is not shut off.

[0024] In step S110, the control device determines whether the driving support function can be safely terminated based on, for example, the behavior information of the vehicle. As a result, if this determination result is Yes (i.e., when the driving support function is in a state where it can be safely terminated), the control device cuts off the power supply of the auxiliary machine C related to driving support in step S112. Next, in step S114, if the sustainable time T1 is greater than or equal to the travelable time T2, the process proceeds to the return, and if the sustainable time T1 is shorter than the travelable time T2, the process proceeds to step S116. Also, if the determination result in step S110 is No (i.e., when the driving support function is not in a state where it can be safely terminated), the process also proceeds to step S116.

[0025] In step S116, the control device determines whether the sustainable time T1 is shorter than a predetermined time T1th2. As a result, if this determination result is Yes (T1 < T1th2), the control device cuts off the power supply of the auxiliary machine D related to preventive safety in step S118. Next, in step S120, if the sustainable time T1 is greater than or equal to the travelable time T2, the process proceeds to the return, and if the sustainable time T1 is shorter than the travelable time T2, the process proceeds to step S122. Also, if the determination result in step S116 is No (T1 ≥ T1th2), the process also proceeds to step S122. Since the auxiliary machine D is related to safety, the power supply of the auxiliary machine D is cut off only when there is no margin in the sustainable time T1.

[0026] In step S122, the control device executes the processes shown in FIGS. 2 and 3 as described below. The processes of the flowchart shown in FIG. 1 described above are repeatedly executed. Therefore, when the process proceeds to step S122, the processes shown in FIGS. 2 and 3 are also repeatedly executed.

[0027] According to the process shown in FIG. 1 described above, basically, the power supply for auxiliary machines is cut off so that the sustainable time T1 becomes longer than the travelable time T2. However, since the roles of the auxiliary machines are different as described above, as shown in FIG. 1, the power supply cut-off (auxiliary machines C and D) is carried out while taking into account not to affect safety. Also, the power supply cut-off (auxiliary machines B to D) may be carried out in a more subdivided manner instead of carrying out all of the auxiliary machines in each classification at once.

[0028] According to the process shown in FIG. 1 described above, by making the restriction of the operation of the auxiliary machines the minimum necessary to make the sustainable time T1 longer than the travelable time T2, it becomes possible to cope with a failure of the power supply that supplies power to the auxiliary battery while reducing the possibility of inconveniencing the vehicle user.

[0029] Next, the process shown in FIG. 2 will be described. Even after the state where only the minimum necessary auxiliary machines are driven by the process shown in FIG. 1 described above, if the travelable time T2 remains, the driver may continue to drive as it is. As a result, there is a possibility that the driving continues until the remaining amount of the auxiliary battery runs out. Therefore, when the sustainable time T1 is shorter than the travelable time T2 (S122; Yes), the process shown in FIG. 2 is executed in order to notify the driver of a place where the vehicle can be safely stopped within the remaining time and prompt the driver to make a safe stop.

[0030] More specifically, in the process shown in FIG. 2, the control device estimates a plurality of candidates for the reachable places of the vehicle based on, for example, vehicle surrounding information, traffic information, and map information together with the sustainable time T1. Then, the control device searches for and selects a parking place (for example, a parking area) where the vehicle can be safely stopped among the plurality of estimated reachable place candidates, and presents the selected parking place to the driver using the display device.

[0031] Then, the presentation of the above parking locations is prioritized as follows, taking into account the safety and convenience of the driver after parking. Examples of parking locations with a "high" priority are places where repairs can be made, such as at a dealer. Examples of parking locations with a "medium" priority are places where there is no problem parking for a long time, such as a parking area or a "rest area parking lot". Examples of parking locations with a "low" priority are places with a certain amount of space, such as a safety zone on a highway. Examples of parking locations with an "extremely low" priority are places where parking can be done quickly, such as the road shoulder. Additionally, the priority may be further refined considering the safety and convenience of the driver, such as giving priority to parking lots near stations so that it is easier for the driver to make the next move after parking.

[0032] In FIG. 2, at step S200, the control device determines whether a place with a "high" priority is included in the candidates for the reachable locations of the vehicle. As a result, if this determination result is Yes, the control device, at step S202, presents a place with a "high" priority to the driver (displays the information of the place on the display device).

[0033] If the determination result at step S200 is No, the control device, at step S204, determines whether a place with a "medium" priority is included in the candidates for the reachable locations of the vehicle. As a result, if this determination result is Yes, the control device, at step S206, presents a place with a "medium" priority to the driver.

[0034] If the determination result at step S204 is No, the control device, at step S208, determines whether a place with a "low" priority is included in the candidates for the reachable locations of the vehicle. As a result, if this determination result is Yes, the control device, at step S210, presents a place with a "low" priority to the driver.

[0035] If the determination result at step S208 is No, the control device, at step S212, presents a place with an "extremely low" priority to the driver.

[0036] Next, the process shown in FIG. 3 will be described. When the remaining amount of the auxiliary battery decreases and a sudden operation of an auxiliary device E related to vehicle running such as an electric power steering or an electric brake is executed, the voltage of the auxiliary battery may greatly decrease, which may affect the operation of the auxiliary device E. Therefore, when the sustainable time T1 is shorter than the travelable time T2 (S122; Yes), the process shown in FIG. 3 is executed in order to ensure the operation of the auxiliary device E while ensuring the safe travel of the vehicle even if a sudden operation of the auxiliary device E (such as an electric power steering) is executed.

[0037] More specifically, in FIG. 3, in step S300, the control device calculates the estimated voltage Vm of the auxiliary battery after it has decreased due to the operation of the auxiliary device E (such as an electric power steering) for each of a plurality of levels. The estimated voltage Vm is calculated, for example, by subtracting the product of the internal resistance of the auxiliary battery and the load current I of the auxiliary device E at each level from the current voltage of the auxiliary battery detected by a voltage sensor. The load current I is calculated by adding up the values of all the auxiliary devices E that can operate at the time of calculating the estimated voltage Vm among the auxiliary devices E related to vehicle running. However, the load current I of the auxiliary device E that is already operating at the time of calculating the estimated voltage Vm is excluded from the calculation of the above load current I. Also, the levels here are set as follows, for example, based on the output of each auxiliary device E. Level 1: Electric power steering output large (200 A) + Electric brake output large (150 A) = 350 A Level 2: Electric power steering output medium (100 A) + Electric brake output large (150 A) = 250 A, or Electric power steering output large (200 A) + Electric brake output medium (50 A) = 250 A Level 3: Electric power steering output medium (100 A) + Electric brake output medium (50 A) = 150 A

[0038] According to the processes of steps S302 to S312 shown in FIG. 3, based on the voltage estimated values Vm of each level calculated as described above, it is determined whether the operation of the auxiliary machine E at which level can be accepted without problems. Then, in order to ensure the operation of the auxiliary machine E at an acceptable level and the safe driving of the vehicle, the vehicle speed is limited while suppressing the output of the auxiliary machine E as necessary.

[0039] Specifically, in step S302, the control device determines whether the voltage estimated value Vm of level 1 is higher than a predetermined voltage Vth. This predetermined voltage Vth is determined in advance based on the minimum operating voltage of the auxiliary machine E that affects the safety and operation of the vehicle. If the determination result is Yes, the process proceeds to the end. That is, the output limit of the auxiliary machine E and the vehicle speed limit are not performed.

[0040] On the other hand, when the voltage estimated value Vm of level 1 is less than or equal to the predetermined voltage Vth (S302; No) and the voltage estimated value Vm of level 2 is higher than the predetermined voltage Vth (S304; Yes), the output of the auxiliary machine E can be generated up to level 2. Therefore, in step S306, the control device limits the output of each auxiliary machine E up to level 2 and limits the vehicle speed to, for example, a speed corresponding to level 2. The said limitation of the vehicle speed is performed by controlling the output of a device related to vehicle drive such as an electric motor or an internal combustion engine.

[0041] Also, when the voltage estimated value Vm of level 2 is less than or equal to the predetermined voltage Vth (S304; No) and the voltage estimated value Vm of level 3 is higher than the predetermined voltage Vth (S308; Yes), the control device limits the output of each auxiliary machine E up to level 3 and limits the vehicle speed to, for example, a speed corresponding to level 3 in step S310.

[0042] Also, when the voltage estimated value Vm of level 3 is less than or equal to the predetermined voltage Vth (S308; No), the control device further limits the output of each auxiliary machine E to be lower than that of level 3 and limits the vehicle speed to a speed even lower than that corresponding to level 3, for example, in step S312.

Claims

【Claim 1】 A control device for controlling a vehicle equipped with an auxiliary battery for driving an auxiliary machine, calculating a travelable time or travelable distance of the vehicle from the remaining energy amount of a power source, calculating a maintainable time or maintainable distance in a state where the remaining amount of the auxiliary battery is equal to or more than a predetermined value, when the maintainable time is shorter than the travelable time, making the maintainable time equal to or more than the travelable time, or when the maintainable distance is shorter than the travelable distance, making the maintainable distance equal to or more than the travelable distance, restricting the operation of the auxiliary machine A control device for a vehicle.

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