Vehicle control device

Abstract

To provide a vehicle control device capable of calculating a discharge amount of a battery by a dark current with high accuracy.SOLUTION: A vehicle control device according to the present invention, includes: a circuit in which a current with a magnitude of 1 / n of a dark current flows on the basis of the dark current flown from a battery in a period when a power supply of a vehicle is turned off; a power storage part that is charged by the current of the magnitude of 1 / n flowing in the circuit; and a processing part that calculates the discharging amount of the battery on the basis of a charging amount of the power storage part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vehicle control device. [Background technology]

[0002] Conventionally, the number of electrical components operating in a parked vehicle has increased, and the dark current flowing from the battery has tended to increase.

[0003] Patent Document 1 discloses a calculation method in which the product of the dark current discharge amount, which is determined as a theoretical value or an empirical value, and the IG off time is calculated as the battery usage amount. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-169395 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, there is an issue that the actual dark current that flows while the vehicle is parked varies, and the number of electrical components that operate while the vehicle is parked is also on the rise, so the value obtained by multiplying a set dark current value by the parking time is less accurate than the actual amount of discharge.

[0006] An object of the present invention is to provide a vehicle control device that is capable of accurately calculating the amount of discharge of a battery due to dark current. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the vehicle control device of the present invention has a circuit through which a current having a magnitude of 1 / n of a dark current flows based on a dark current flowing from a battery during a period when the vehicle power supply is turned off, a storage unit that is charged by the 1 / n current flowing in the circuit, and a processing unit that calculates the amount of discharge of the battery based on the amount of charge in the storage unit. Effect of the Invention

[0008] According to the present invention, the amount of discharge of a battery due to dark current can be calculated with high accuracy. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating an example of a configuration of a vehicle control device according to an embodiment. [Diagram 2] FIG. 2 is an explanatory diagram of a process performed by a vehicle control device according to a modified example of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] In the following, a vehicle control device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following embodiment, and the components in the following embodiment include those that a person skilled in the art can easily conceive, those that are substantially the same, and those that are within the scope of what is called equivalent. Furthermore, various omissions, substitutions, modifications, and combinations of the components can be made without departing from the gist of the following embodiment.

[0011] <Embodiment> The vehicle control device according to the embodiment can be applied to various vehicles equipped with a battery, and the vehicle may be any of a hybrid vehicle, an electric vehicle, and an engine vehicle.

[0012] Fig. 1 is a diagram showing an example of the configuration of a vehicle control device according to an embodiment. Fig. 1 shows a schematic diagram of the configuration of a vehicle control device 1, a battery 20, and a plurality of electric loads 30.

[0013] The vehicle control device 1 is, for example, an ECU (Electronic Control Unit) that manages a battery 20.

[0014] The battery 20 is used for driving the vehicle.

[0015] The electrical loads 30 are electrical components that operate by receiving electricity from the battery 20, and examples of the electrical loads 30 include other ECUs and various sensors mounted on the vehicle.

[0016] The switch section 10 is a switch that shows the state of a main switch of a vehicle. The main switch is a start switch that is provided in the vehicle and is operated by touch or by rotating a key.

[0017] Here, the period during which the main switch is off corresponds to the "period during which the vehicle's power supply is off." Specifically, it refers to the period during which the vehicle is not powered, such as when the ACC is off or the Ready is off. One example of this period is when the vehicle is parked, so it may also be described as when the vehicle is parked.

[0018] When the switch unit 10 is on, it indicates that the main switch is in either the ACC (accessory) or IG (ignition) state, and when it is off, it indicates that the main switch is off. In the following, the distinction between ACC and IG will be omitted as necessary.

[0019] In the vehicle control device 1 shown in FIG. 1, when the switch unit 10 is turned off, a first path for supplying electricity from the power supply terminal a1 of the battery 20 to the electrical load 30 is interrupted and switched to a second path for supplying electricity from the battery 20 to the electrical load 30.

[0020] Some of the electric loads 30 continue to operate even after the main switch of the vehicle is turned off. One example is an ECU that monitors the state of a parked vehicle. The second path is a path that constantly supplies electricity to the electric loads 30 that continue to operate even after the main switch of the vehicle is turned off.

[0021] 1 is a PNP-type current mirror circuit. A collector terminal b1 of a bipolar transistor 110 and base terminals of the bipolar transistors 110 and 111 are connected to each other.

[0022] When the switch unit 10 is turned off, the bipolar transistor 110 and the bipolar transistor 111 are turned on and become conductive. When the electrical load 30 operates after the switch unit 10 is turned off, the dark current I flows from the battery 20 to the electrical load 30 via the current side path, which is the second path. Here, of the current paths of the bipolar transistor 110 and the bipolar transistor 111, the bipolar transistor 110 side is called the current side, and the bipolar transistor 111 side is called the mirror side.

[0023] A current flows on the mirror side that is 1 / n (n is a positive integer) times the dark current I that flows on the current side. For convenience, below, the current that is 1 / n the size of the dark current I will be called the measurement current i.

[0024] The mirror ratio of the current mirror circuit 11, n:1, is, for example, 1000:1.

[0025] On the mirror side, a capacitor 12 is provided between the collector terminal b2 of the bipolar transistor 111 and ground. The capacitor 12 is charged by the flow of a measurement current i. The capacitor 12 is an example of a "power storage unit."

[0026] An output terminal a3 is connected to a node a2 between the collector terminal b2 of the bipolar transistor 111 and the capacitor 12.

[0027] The processing unit 13 reads the voltage V of the capacitor 12 via the wiring of the output terminal a3, and calculates the discharge amount of the battery 20 based on the charge amount of the capacitor 12. The processing unit 13 has a computer such as a CPU (Central Processing Unit), for example, and calculates the discharge amount as follows.

[0028] First, the processing unit 13 reads the voltage V1 of the capacitor 12 from the output terminal a3 when the switch unit 10 is turned on (step S1).

[0029] Next, the processing unit 13 reads the voltage V2 of the capacitor 12 from the output terminal a3 at any timing after the switch unit 10 is turned off (step S2).

[0030] Next, the processing unit 13 calculates the amount of charge Q of the capacitor 12 charged by the measurement current i, for example, by using the following equation (1) (step S3).

[0031] Q = C(V2 - V1) (1)

[0032] Here, C is the capacitance of the capacitor 12.

[0033] Next, the processing unit 13 calculates the discharge amount X of the battery 20 by using the following equation (2) or the like (step S4).

[0034] X = Q(n + 1) (2)

[0035] Here, Q×n is the discharge amount X1 due to the dark current I flowing on the current side, and Q×1 is the discharge amount X2 due to the measurement current i flowing on the mirror side. The sum of the discharge amount X1 and the discharge amount X2 is the discharge amount X of the battery 20.

[0036] After the switch unit 10 is turned on again, the bipolar transistors 110 and 111 are turned off, forming the first path on the switch unit 10 side. In this embodiment, the charge stored in the capacitor 12 is discharged by the discharge means when the main switch of the vehicle is turned off. Since it is only necessary that the charge corresponding to the measurement current i that flowed during the period when the power supply of the vehicle was turned off is stored in the capacitor 12, the timing of discharging the charge of the capacitor 12 by the discharge means may be before the main switch of the vehicle is turned off, and the discharge timing can be set appropriately. The charge stored in the capacitor 12 may be discharged by, for example, a discharge circuit 14 described later, or by other discharge means.

[0037] When the main switch of the vehicle is in the ACC on or IG on state, electricity from the battery 20 is supplied to the electric load 30 via a first path by the ACC power source or the IG power source.

[0038] In addition, if the mirror ratio of the current mirror circuit 11 is increased, the capacitance of the capacitor 12 can be reduced, resulting in lower costs. The mirror ratio is changeable because it varies with the size ratio of the transistors.

[0039] In the present embodiment, a current mirror circuit is used as an example of a circuit through which a current 1 / n times the dark current I flows, but the circuit is not limited to a current mirror circuit. Any other circuit may be used as long as a current 1 / n times the dark current I flows.

[0040] Furthermore, the circuit configuration of the capacitor 12 may be modified as appropriate as long as the amount of discharge of the battery 20 can be calculated from the amount of charge charged by the measurement current i.

[0041] Furthermore, the vehicle control device 1 has been described as an ECU that manages the battery 20 as an example, but if the ECU is not functionally divided, it may be applied to an integrated ECU.

[0042] In this way, the vehicle control device 1 of this embodiment charges the capacitor 12 with the measurement current i that changes in proportion to the magnitude of the dark current I that actually flows from the battery 20, and calculates the discharge amount based on the charge Q stored in the capacitor 12. Without directly measuring the dark current, the discharge amount of the battery 20 can be accurately calculated by following the change in the magnitude of the dark current I. Although the accuracy depends in part on the accuracy of the circuit, the vehicle control device 1 of this embodiment can determine the circuit according to the required accuracy, so it is possible to accurately calculate the discharge amount.

[0043] Furthermore, the vehicle control device 1 of the present embodiment can achieve high accuracy with a simple and low-cost configuration without using an expensive battery sensor or a function for automatically starting the ECU.

[0044] In addition, since the vehicle control device 1 of this embodiment can calculate the discharge amount using a small amount of electricity during the period when the vehicle's power is turned off, it is also possible to calculate the discharge amount at any time, and it is also possible for the user to check the deterioration and remaining capacity of the battery 20 each time the vehicle is parked for a long period of time, for example.

[0045] Furthermore, the vehicle control device 1 of this embodiment can accurately calculate the discharge amount of the battery 20 during the period when the vehicle power is off. When the accurate discharge amount is known during the period when the vehicle power is off, the current remaining capacity of the battery 20 can be known by subtracting the discharge amount from the previous remaining capacity of the battery 20 (for example, 90% remaining capacity). Therefore, the vehicle can accurately detect the remaining capacity of the battery 20 when the main switch is operated to start the vehicle again. Therefore, when the battery 20 has not decreased much and the remaining capacity exceeds a predetermined level, such as when the vehicle has been parked for a short period of time, the reliability of the value is high, and it is possible to avoid charging the battery 20 by generating electricity every time the battery is started.

[0046] (Modification of the embodiment) When the charge of the capacitor 12 charged by the measurement current i reaches the upper limit of the capacity of the capacitor 12, it is no longer possible to store any more charge. When using a capacitor 12 with a small capacity, modifications can be made such as providing a discharge circuit and a counter to calculate the amount of discharge. As an example, as shown in Figure 1, a discharge circuit 14 and a counter 15 are provided.

[0047] The discharge circuit 14 discharges the capacitor 12 when the capacitor 12 reaches a predetermined charged state. The predetermined charged state refers, for example, to a state in which the voltage V of the capacitor 12 reaches a threshold value v0. In the example shown in Fig. 1, the discharge circuit 14 is provided between the wiring connecting the output terminal a3 and the processing unit 13 and the ground. The discharge circuit 14 discharges the capacitor 12 when the voltage V of the capacitor 12 reaches the threshold value v0.

[0048] 1, counter 15 is provided between the wiring connecting output terminal a3 and processing unit 13 and ground. Counter 15 counts up at the timing when discharging is performed by discharge circuit 14 by monitoring a change in the value of voltage V of capacitor 12, and outputs a counter value indicating the number of discharges after the count up to processing unit 13.

[0049] The discharge circuit 14 and the counter 15 may be configured with digital circuits or analog circuits. When configured with digital circuits, it is possible to further reduce power consumption.

[0050] Fig. 2 is an explanatory diagram of processing by the vehicle control device 1 according to a modified example of the embodiment. Fig. 2 shows, in a timing chart, changes in the switch state of the switch unit 10, the voltage V of the capacitor 12, and the counter value of the counter 15 indicating the number of discharges along the time axis.

[0051] The switch state is ON when the main switch is ON and power is supplied to the vehicle, and OFF when the main switch is OFF and power is not supplied to the vehicle. In other words, OFF corresponds to "a period when the power supply to the vehicle is OFF."

[0052] When the switch state is switched from on to off, charging of the voltage V of the capacitor 12 starts and the voltage value increases. If the switch state is subsequently switched on before the voltage value reaches the threshold value v0, the capacitor 12 is not discharged even once, and the counter value indicating the number of discharges is "0".

[0053] The processing unit 13 reads the voltage value of the capacitor 12 and the counter value of the counter 15, and calculates the discharge amount of the battery 20 during the vehicle non-powered period. During the first vehicle non-powered period, the number of discharges is "0", so that the discharge amount of the battery 20 is calculated only from the voltage value of the capacitor 12.

[0054] Next, when the switch state is switched from on to off, charging of the voltage V of the capacitor 12 starts in the same way as the first time, and the voltage value rises. After that, the voltage value reaches the threshold value v0, and the capacitor 12 starts discharging. Furthermore, thereafter, the capacitor 12 starts discharging every time the voltage value reaches the threshold value v0.

[0055] The counter value is incremented to "1" by the first discharge of the capacitor 12. It is further incremented to "2" by the second discharge.

[0056] After this, when the switch state is turned on, since the capacitor 12 has been discharged twice, the processing unit 13 reads the current voltage value of the capacitor 12 and the counter value "2" of the counter 15, and calculates the amount of discharge of the battery 20 during the second vehicle non-powered period.

[0057] 1 is merely an example, and is not intended to be limiting. As long as the functions of the discharge circuit 14 and counter 15 described above are achieved, the configurations of the discharge circuit 14 and counter 15 may be modified as appropriate.

[0058] In this manner, the vehicle control device 1 according to the modified example of the present embodiment is provided with the discharge circuit 14 and the counter 15. By providing the discharge circuit 14 and the counter 15, the capacitance of the capacitor 12 can also be made smaller.

[0059] In addition, when the vehicle is parked for a long period of time, a large amount of dark current I will flow accordingly. However, since the charge stored by the current that has flowed is stored in counter 15 even in capacitor 12 with a small capacity, the discharge amount of battery 20 can be calculated accurately regardless of the parking period.

[0060] Moreover, by using a digital circuit configuration, power consumption can be reduced.

[0061] Furthermore, in the past, the charge amount could not be calculated until charging of the battery 20 started, so charging was always performed at the start of the vehicle. The vehicle control device 1 of the present embodiment and the modified example can determine the charge amount without starting charging, simply by turning on the power, i.e., by turning on the electricity.

[0062] The vehicle control device 1 may further be connected to a communication device to transmit information about the battery 20 to the outside. The communication device is, for example, a wireless communication device that communicates with an external server or a short-range wireless communication device that communicates with a smartphone. For example, the vehicle control device 1 notifies the user's smartphone of information via the communication device while the vehicle is parked, and the user can know the remaining capacity of the vehicle's battery 20 from the smartphone. [Explanation of symbols]

[0063] 1 Vehicle control device 10 Switch section 11 Current mirror circuit 12 Capacitor 13 Processing section 14 Discharge circuit 15 Counter 20 Battery 30 Electrical Load 110, 111 Bipolar transistor a3 Output terminal I dark current i Measuring current

Claims

1. a circuit through which a current flows that is 1 / n of a dark current flowing from a battery during a period when the vehicle power supply is turned off; a power storage unit that is charged by a current having a magnitude of 1 / n that flows through the circuit; A processing unit that calculates a discharge amount of the battery based on the charge amount of the power storage unit; A vehicle control device having the above configuration.

2. a discharge circuit that discharges the power storage unit when the power storage unit reaches a predetermined charged state; a counter that counts the number of discharges by the discharge circuit; and the processing unit calculates a discharge amount of the battery based on the charge amount of the power storage unit and the number of discharges counted by the counter; The vehicle control device according to claim 1 .

3. The circuit is a current mirror circuit in which a current having a magnitude of 1 / n flows in a mirror side based on the dark current flowing in a current side. The vehicle control device according to claim 1 or 2.

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