Vehicle control system

Abstract

To provide a vehicle control system capable of suppressing a used power amount in a period during which an ignition switch is turned off.SOLUTION: A vehicle control system, which performs auxiliary machine charging control of charging a low voltage battery 4 by power accumulated in a high voltage battery 2 in a period during which an ignition switch 7 is turned off, includes a transmission part 11 for transmitting a start signal at set time, and a control part 10 for executing the auxiliary machine charging control when receiving the start signal.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vehicle control system.

Background Art

[0002] Conventionally, a first battery, a DC / DC converter directly connected to the first battery and supplied with power from the first battery, and a second battery supplied with power from the DC / DC converter and supplied with low voltage to a low-voltage system via an ignition switch are provided. When it is detected that the ignition switch is in a state of not supplying power to the low-voltage system, the measurement of time is started. When the measured value is outside the range of the first threshold value, the DC / DC converter is started. When the measured value is outside the range of the second threshold value, the DC / DC converter is stopped and the measured value is reset to the initial value, and the charging control process is repeatedly executed. When it is detected that the ignition switch is in a state of supplying power to the low-voltage system, the charging control process is stopped. A technique has been proposed in Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional technology as described above, since it is necessary to continuously activate a control device such as an ECU in order to count up the integrated time during which the ignition switch is off, there is a problem that the power consumption during the period when the ignition switch is off increases.

[0005] The present invention has been made to solve the above problems, and an object thereof is to provide a vehicle control system capable of suppressing the power consumption during the period when the ignition switch is off.

Means for Solving the Problem

[0006] The vehicle control system according to the present invention is a vehicle control system that performs auxiliary charging control for charging a low-voltage battery with electric power output from a high-voltage battery during a period when the ignition switch is off, and includes a transmission unit that transmits an activation signal at a set time, and a control unit that executes the auxiliary charging control when the activation signal is received.

Effect of the Invention

[0007] The present invention can provide a vehicle control system capable of suppressing the amount of power consumed during a period when the ignition switch is off.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0009] A vehicle control system according to an embodiment of the present invention is a vehicle control system that performs auxiliary charging control for charging a low-voltage battery with electric power output from a high-voltage battery during a period when the ignition switch is off, and is characterized by including a transmission unit that transmits an activation signal at a set time, and a control unit that executes the auxiliary charging control when the activation signal is received. Thereby, the vehicle control system according to an embodiment of the present invention can suppress the amount of power consumed during a period when the ignition switch is off.

Example

[0010] Hereinafter, a vehicle equipped with a vehicle control system according to an embodiment of the present invention will be described with reference to the drawings.

[0011] As shown in FIG. 1, the vehicle 1 is composed of an electric vehicle including a high-voltage battery 2, a DC / DC converter 3, a low-voltage battery 4, a first ECU (Electronic Control Unit) 5, a second ECU 6, and an ignition switch 7.

[0012] The high-voltage battery 2 is composed of a rechargeable secondary battery, for example, a lithium-ion battery. The high-voltage battery 2 is provided to be rechargeable from the outside and accumulates the charged power. The power accumulated in the high-voltage battery 2 is consumed, for example, as the driving power of the vehicle 1.

[0013] The DC / DC converter 3 converts the high-voltage power supplied by the high-voltage battery 2 into low-voltage power. The low-voltage power converted by the DC / DC converter 3 is supplied to the low-voltage battery 4.

[0014] The low-voltage battery 4 is composed of a rechargeable secondary battery, for example, a lead battery or a lithium-ion battery. The low-voltage battery 4 accumulates the low-voltage power supplied from the DC / DC converter 3. The power accumulated in the low-voltage battery 4 is consumed by a low-voltage electrical load that operates at a low voltage.

[0015] The low-voltage electrical load includes a first load that operates with the power supplied from the low-voltage battery 4 when the ignition switch 7 is on and stops operating when the ignition switch 7 is turned off, and a second load that operates with the power supplied from the low-voltage battery 4 regardless of the state of the ignition switch 7. For example, the second ECU 6 is included in the second load.

[0016] The first ECU 5 is composed of a computer unit including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a flash memory.

[0017] In the ROM of this computer unit, a program for causing the computer unit to function as the first ECU 5 is stored together with various constants and various maps. That is, when the CPU executes the program stored in the ROM using the RAM as a work area, this computer unit functions as the first ECU 5 in this embodiment.

[0018] The first ECU 5 has a first power supply port 8a to which power is supplied from the low-voltage battery 4 via the ignition switch 7, and a second power supply port 8b to which power is supplied from the low-voltage battery 4 without passing through the ignition switch 7.

[0019] When the ignition switch 7 is on, the first ECU 5 operates on the power supplied from the first power supply port 8a without consuming the power supplied from the second power supply port 8b. For example, when power is supplied from the first power supply port 8a, the first ECU 5 controls the running state of the vehicle 1.

[0020] When the ignition switch 7 is turned off, the first ECU 5 operates on the power supplied from the second power supply port 8b. When the first ECU 5 operates on the power supplied from the second power supply port 8b, it shifts to a power-saving mode in which execution is permitted only for some functions including a receiving function for receiving a signal transmitted from the second ECU 6. When a start signal is received from the second ECU 6 in the power-saving mode, the first ECU 5 shifts to an operating mode.

[0021] In the operation mode, if the number of receptions of the start signal by the first ECU 5 is equal to or more than a predetermined number, the first ECU 5 executes auxiliary charging control to control the DC / DC converter 3 to charge the low-voltage battery 4 with the power stored in the high-voltage battery 2, and shifts to the power saving mode when the execution of the auxiliary charging control is completed. The predetermined number is determined to be one or more according to the interval of the transmission time of the start signal by the second ECU 6.

[0022] As described above, the first ECU 5 has a function as a control unit 10 that executes auxiliary charging control when receiving the start signal. In the operation mode, if the number of receptions of the start signal by the first ECU 5 is less than the predetermined number, the first ECU 5 shifts to the power saving mode without executing the auxiliary charging control.

[0023] The second ECU 6 is composed of a computer unit including a CPU, a RAM, and a ROM. In the ROM of this computer unit, a program for causing the computer unit to function as the second ECU 6 is stored together with various constants, various maps, and the like. That is, by the CPU executing the program stored in the ROM using the RAM as a work area, this computer unit functions as the second ECU 6 in the present embodiment.

[0024] The second ECU 6 operates with the power supplied from the low-voltage battery 4 regardless of the state of the ignition switch 7. In the present embodiment, the second ECU 6 controls the instrument panel of the vehicle 1. The second ECU 6 has a clock function for displaying the time on the instrument panel.

[0025] When the ignition switch 7 is turned off, the second ECU 6 transmits a start signal to the first ECU 5 at the set time. As described above, the second ECU 6 has a function as a transmission unit 11 that transmits a start signal at the set time.

[0026] The second ECU 6 determines the set times at predetermined time intervals based on the time when the ignition switch 7 is turned off. The predetermined time is set to 2 hours in this embodiment, but may be set to any time longer than 0.

[0027] For example, if the time when the ignition switch 7 is turned off is 12:20:20, the second ECU 6 determines 14:20:20, 16:20:20, 18:20:20, 20:20:20, 22:20:20, 0:20:20, 2:20:20, 4:20:20, 6:20:20, 8:20:20, 10:20:20, and 12:20:20 as the set times.

[0028] The operation of transmitting the start signal by the second ECU 6 configured as described above will be described with reference to FIG. 2. Note that the operation of transmitting the start signal described below is repeatedly executed during the period when the ignition switch 7 is off.

[0029] First, in S1, the second ECU 6 determines whether the current time has reached the set time. If it is determined in S1 that the current time has reached the set time, the second ECU 6 executes the process of S2. If it is determined in S1 that the current time has not reached the set time, the second ECU 6 ends the operation of transmitting the start signal. In S2, the second ECU 6 transmits the start signal to the first ECU 5. After executing the process of S2, the second ECU 6 ends the operation of transmitting the start signal.

[0030] Hereinafter, the operation when the first ECU 5 receives the start signal will be described with reference to FIG. 3. Note that the operation when the start signal is received described below is executed based on the reception of the start signal from the second ECU 6. That is, the operation when the start signal is received is executed based on the first ECU 5 shifting from the power saving mode to the operating mode.

[0031] First, in S11, the first ECU 5 adds 1 to the number of times the startup signal is received (hereinafter, also simply referred to as the "number of startup signal receptions"). After executing the process of S11, the first ECU 5 executes the process of S12.

[0032] In S12, the first ECU 5 determines whether the number of startup signal receptions is equal to or greater than a predetermined number. If it is determined that the number of startup signal receptions is equal to or greater than the predetermined number, the first ECU 5 executes the process of S13. If it is determined that the number of startup signal receptions is less than the predetermined number, the first ECU 5 executes the process of S16.

[0033] In S13, the first ECU 5 executes auxiliary machine charging control. After executing the process of S13, the first ECU 5 executes the process of S14. In S14, the first ECU 5 determines whether the auxiliary machine charging control has been completed. For example, if the charging rate of the low-voltage battery 4 is equal to or greater than the target value during charging, the first ECU 5 completes the auxiliary machine charging control.

[0034] In S14, if it is determined that the auxiliary machine charging control has been completed, the first ECU 5 executes the process of S15. In S14, if it is determined that the auxiliary machine charging control has not been completed, the first ECU 5 executes the process of S13. That is, in S14, if it is determined that the auxiliary machine charging control has not been completed, the first ECU 5 enters a waiting state for the completion of the auxiliary machine charging control.

[0035] In S15, the first ECU 5 resets the number of startup signal receptions to 0. After executing the process of S15, the first ECU 5 executes the process of S16. In S16, the first ECU 5 stores the number of startup signal receptions in a non-volatile memory such as a flash memory. After executing the process of S16, the first ECU 5 executes the process of S17. In S17, the first ECU 5 shifts to the power-saving mode. After executing the process of S17, the first ECU 5 ends the operation when the startup signal is received.

[0036] In this way, according to the start signal transmission operation by the second ECU 6 and the operation when the start signal is received by the first ECU 5, during the period when the ignition switch 7 is off, the auxiliary machine charging control is executed at time intervals obtained by multiplying the time interval of the set time set by the second ECU 6 by the predetermined number of times compared with the number of start signal receptions by the first ECU 5.

[0037] For example, during the period when the ignition switch 7 is off, if the time interval of the set time set by the second ECU 6 is 2 hours and the predetermined number of times compared with the number of start signal receptions by the first ECU 5 is 3 times, the auxiliary machine charging control is executed at 6-hour intervals.

[0038] Also, during the period when the ignition switch 7 is off, if the time interval of the set time set by the second ECU 6 is 2 hours and the predetermined number of times compared with the number of start signal receptions by the first ECU 5 is 1 time, the auxiliary machine charging control is executed at 2-hour intervals.

[0039] As described above, the vehicle control system according to this embodiment includes a transmission unit 11 that transmits a start signal at a set time and a control unit 10 that executes auxiliary machine charging control when the start signal is received. Therefore, it is not necessary to count up the integrated time during the period when the ignition switch 7 is off, and it is not necessary to continuously start the first ECU 5 during the period when the ignition switch 7 is off. Therefore, the vehicle control system according to this embodiment can suppress the power consumption during the period when the ignition switch 7 is off.

[0040] Also, in the vehicle control system according to this embodiment, when the ignition switch 7 is turned off, the first ECU 5 shifts to the power-saving mode. When a start signal is received in the power-saving mode, it shifts to the operation mode. When it shifts to the operation mode, it executes the auxiliary machine charging control, and when the execution of the auxiliary machine charging control is completed, it shifts to the power-saving mode. Therefore, the vehicle control system according to this embodiment can suppress the power consumption of the first ECU 5 during the period when the ignition switch 7 is off.

[0041] Also, in the vehicle control system according to this embodiment, when the number of times of receiving the start signal reaches a predetermined number, the first ECU 5 executes auxiliary machine charging control. Therefore, the vehicle control system according to this embodiment can change the timing of executing the auxiliary machine charging control by changing the program executed by the CPU of the first ECU 5 without changing the specifications of the second ECU 6.

[0042] In addition, in the vehicle control system according to this embodiment, since the second ECU 6 has a clock function and does not start other ECUs in order to transmit a start signal during the period when the ignition switch 7 is off, the power consumption during the period when the ignition switch 7 is off can be suppressed.

[0043] In this embodiment, an example has been described in which the second ECU 6 determines the set time at a predetermined time interval based on the time when the ignition switch 7 is turned off. On the other hand, the second ECU 6 may determine the set time by adding a predetermined time to the time when the ignition switch 7 is turned off, and when the set time is reached, determine the next set time by adding a predetermined time to the set time.

[0044] For example, if the predetermined time is 2 hours and the time when the ignition switch 7 is turned off is 12:20:20, the second ECU 6 may determine 14:20:20 as the set time, transmit a start signal when the current time reaches 14:20:20, then determine 16:20:20 as the set time, transmit a start signal when the current time reaches 16:20:20, and then determine 18:20:20 as the set time.

[0045] As described above, although the embodiments of the present invention have been disclosed, it is obvious that changes can be made to this embodiment without departing from the scope of the present invention. The embodiments of the present invention are disclosed on the premise that equivalents to which such changes are made are included in the invention described in the claims.

Explanation of Reference Numerals

[0046] 2 High-voltage battery 4 Low-voltage battery 6 Second ECU (ECU with clock function) 7 Ignition switch 10 Control unit 11 Transmission unit

Claims

1. A vehicle control system that performs auxiliary charging control to charge a low-voltage battery with the power stored in a high-voltage battery during a period when the ignition switch is off, a transmission unit that transmits an activation signal at a set time, and a control unit that executes the auxiliary charging control when the activation signal is received, characterized in that it comprises a vehicle control system.

2. When the ignition switch is turned off, the control unit shifts to a power-saving mode, shifts to an operating mode when the activation signal is received in the power-saving mode, executes the auxiliary charging control when shifting to the operating mode, and shifts to the power-saving mode when the execution of the auxiliary charging control is completed. The vehicle control system according to claim 1, characterized in that

3. The vehicle control system according to claim 1, characterized in that the control unit executes the auxiliary charging control when the number of times the activation signal is received reaches a predetermined number of times.

4. The vehicle control system according to any one of claims 1 to 3, characterized in that the transmission unit is constituted by an ECU having a clock function.

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