Control device

Abstract

To provide a control device enabling avoidance of the occurrence of such a problem that an engine stops when power generation by an alternator is required in power supply to an on-vehicle load.SOLUTION: A control device is provided, controlling a power source system comprising: a DCDC converter supplying power of a power supply source to load; an alternator parallelly connected to the DCDC converter in such a way as to supply power generated by rotation of an engine to load; and a battery connected to the load in such a way as to supply the power to the load. The control device includes: an acquisition part acquiring information on the electric current of the battery; and a control part controlling the motion of the engine and the alternator on the basis of the acquired information. The control part inhibits stop of an operating engine when the battery is in a discharge state where the current is output to the load.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a control device for a vehicle that controls output power of a power supply system. [Background technology]

[0002] Patent Document 1 discloses a control device for a hybrid vehicle that stops the engine (idle stop) when a predetermined automatic stop condition based on the temperature of engine coolant and the vehicle speed is met. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-020584 Summary of the Invention [Problem to be solved by the invention]

[0004] The control device described in Patent Document 1 determines whether to stop the engine based on the temperature of the engine coolant and the vehicle speed. Therefore, even in a situation where, for example, the demand for power due to the load mounted on the vehicle increases and power supply from not only the battery but also an alternator that generates power through engine rotation is required, the engine may be stopped due to the establishment of an automatic stop condition. In this situation, it may be possible to perform control such as restarting the stopped engine to supply power, but such engine operation (restarting the engine immediately after stopping it) is wasteful and should be avoided.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a control device that can prevent the engine from stopping when power generation by the alternator is required to supply power to a vehicle load. [Means for solving the problem]

[0006] In order to solve the above problems, one aspect of the disclosed technology is a control device for controlling a power supply system, which includes a DC-DC converter that supplies power from a power supply source to a load, an alternator connected in parallel with the DC-DC converter so that power generated by engine rotation can be supplied to the load, and a battery connected to the load so that power can be supplied, and the control device includes an acquisition unit that acquires information about the battery current, and a control unit that controls the operation of the engine and the alternator based on the information, and the control unit prohibits the stopping of a running engine when the battery is in a discharging state where it outputs current to the load. [Effects of the Invention]

[0007] According to the control device of the present disclosure, when the alternator needs to supply power to the load, such as when the power supplied by the DC-DC converter is insufficient and the battery needs to discharge to the load, stopping the engine is prohibited. This prevents the engine from stopping when the alternator needs to generate power, and eliminates unnecessary stopping and restarting of the engine. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram of a control device and its peripheral components according to an embodiment of the present disclosure; [Figure 2A] Flowchart of power control process executed by the control device [Figure 2B] Flowchart of power control process executed by the control device DETAILED DESCRIPTION OF THE INVENTION

[0009] The control device of the present disclosure determines whether to stop the engine depending on whether or not the alternator needs to generate power, based on whether or not there is a discharge current from the auxiliary battery to the auxiliary load, thereby preventing the engine from stopping when power generation by the alternator is required. Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0010] <Embodiment> [composition] Fig. 1 is a functional block diagram showing a schematic configuration of a control device 50 and its peripheral parts according to an embodiment of the present disclosure. The functional block illustrated in Fig. 1 includes a power supply system 10, a power supply source 20, an engine 30, a load 40, and the control device 50. In Fig. 1, power lines through which power is exchanged are indicated by solid lines, and signal lines through which control instructions, detected values, etc. are exchanged are indicated by dashed lines.

[0011] The control device 50 according to this embodiment is mounted on a vehicle such as a hybrid electric vehicle (HEV) or a plug-in hybrid electric vehicle (PHEV) that uses an internal combustion engine 30 as a power source.

[0012] The power supply system 10 is configured to supply power to a load 40. The power supply system 10 includes a battery 11, a DC-DC converter 12, an alternator 13, and a sensor 14.

[0013] The battery 11 is a secondary battery configured to be chargeable and dischargeable, such as a lithium ion battery. The battery 11 is connected to the DC-DC converter 12 so as to be chargeable by the power output from the power supply source 20. The battery 11 can also supply the power stored therein to the load 40. An example of the battery 11 is an auxiliary battery mounted on a vehicle.

[0014] The DC-DC converter 12 is a power converter that can convert input power into power of a predetermined voltage and output it. One end (primary side) of this DC-DC converter 12 is connected to a power supply source 20, and the other end (secondary side) is connected to a battery 11. The DC-DC converter 12 can supply power output by the power supply source 20 connected to the primary side to the battery 11 and load 40 connected to the secondary side. The operation of this DC-DC converter 12 is controlled by a control device 50.

[0015] The alternator 13 is a generator that can generate electricity in response to the rotation (drive) of the engine 30. The alternator 13 is connected in parallel with the DCDC converter 12 so that it can output its own generated power together with the power of the DCDC converter 12 to the battery 11 and the load 40. The control device 50 controls whether the alternator 13 is capable of generating power (whether or not the generated power is output).

[0016] The sensor 14 is configured to detect at least the current flowing out of the battery 11 and the current flowing into the battery 11 as physical quantities of the battery 11. A detection device such as a current sensor is used as the sensor 14. Information relating to the current of the battery 11 detected by the sensor 14 is output to the control device 50.

[0017] The power supply source 20 is configured to supply power exclusively to a main load (such as the engine 30) such as electronic devices and equipment related to the running of the vehicle. The power supply source 20 also supplies power to a load 40, which is an auxiliary load other than the main load, via a DC-DC converter 12. For example, a secondary battery (main battery) such as a lithium-ion battery, or a power generating device such as a motor generator that generates regenerative power, is used as the power supply source 20.

[0018] The engine 30 is an internal combustion engine that serves as a power source for the vehicle. The engine 30 is started using electric power from the power supply source 20. The start / stop of the engine 30 and whether or not to start / stop the engine 30 are permitted are controlled by a control device 50.

[0019] The load 40 is an auxiliary load such as an electronic device or equipment that is not involved in the running of the vehicle. The load 40 is configured to operate mainly on the power of the power supply source 20 supplied via the DC-DC converter 12 and the power generated by the alternator 13, and in certain cases, on the power of the battery 11.

[0020] The control device 50 is configured to control the power output (supplied) from the power supply system 10 to the load 40. The control device 50 includes an acquisition unit 51 and a control unit 52.

[0021] The acquisition unit 51 acquires information about the current of the battery 11 from the sensor 14 of the power supply system 10. The information about the current of the battery 11 acquired by the acquisition unit 51 is the inflow current (charging current) input to the battery 11 or the outflow current (discharging current) output from the battery 11 at the time of acquisition (present).

[0022] The control unit 52 controls the operation of the alternator 13 and the engine 30 of the power supply system 10 based on the information about the current of the battery 11 acquired by the acquisition unit 51. Details of the control will be described later, but when the battery 11 is in a discharging state where it outputs current to the load 40, the control unit 52 performs control to prohibit the engine 30, which is running, from stopping so that the alternator 13 can generate power.

[0023] Note that part or all of the above-described control device 50 may be configured by an electronic control unit (HV_ECU, EFI_ECU, etc.) that typically includes a processor such as a microcomputer, a memory, an input / output interface, etc. This electronic control unit can realize part or all of the functions performed by the above-described acquisition unit 51 and control unit 52 by having the processor read and execute a program stored in the memory.

[0024] [control] Next, the control performed by the control device 50 according to this embodiment will be described with further reference to Figures 2A and 2B. Figures 2A and 2B are flowcharts illustrating the power control processing steps performed by each component of the control device 50. The processing in Figure 2A and the processing in Figure 2B are connected by connectors X and Y, respectively.

[0025] 2A and 2B is started when the vehicle is powered on (IG-ON, READY-ON). This power control is started on the assumption that the alternator 13 is not operating (not generating electricity) at the time of starting the power control, but the operating state of the engine 30 is not particularly limited.

[0026] (Step S201) The acquisition unit 51 of the control device 50 acquires information relating to the current of the battery 11 from the sensor 14. When the acquisition unit 51 acquires the information relating to the current of the battery 11, the process proceeds to step S202.

[0027] The acquisition of information relating to the current of the battery 11 by the acquisition unit 51 is appropriately performed based on a predetermined timing (such as a fixed cycle) even during the processing of each step described below.

[0028] (Step S202) The control unit 52 of the control device 50 determines whether the battery 11 is in a discharging state. This determination can be made based on the current inflow / outflow current of the battery 11 and / or the integrated value of the inflow / outflow current up to the present, which are obtained from the information acquired by the acquisition unit 51 in step S201.

[0029] For example, the following can be done based on the current input / output current of the battery 11. If the power demand (current consumption) of the load 40 does not exceed the supply capacity (output limit) of the DC-DC converter 12, the surplus power (current) is input to the battery 11 to charge it, or the DC-DC converter 12 is controlled so that the surplus power is eliminated. Therefore, in this case, current flows into the battery 11 or the current becomes zero, so the control unit 52 can determine that the battery 11 is in a charging state. On the other hand, if the power demand of the load 40 exceeds the supply capacity of the DC-DC converter 12, the battery 11 outputs the insufficient power (current) to the load 40 and discharges it. Therefore, in this case, current flows out of the battery 11, so the control unit 52 can determine that the battery 11 is in a discharging state. Note that the discharging state of the battery 11 may be determined not simply based on whether or not there is a current flowing out of the battery 11, but also based on whether or not there is a current flowing out of the battery 11 equal to or greater than a predetermined threshold.

[0030] Furthermore, the following can be performed based on the accumulated value of the current input / output current of the battery 11. For example, the control unit 52 accumulates the current input / output currents sequentially acquired by the acquisition unit 51, with the current flowing into the battery 11 indicated as a positive value and the current flowing out from the battery 11 indicated as a negative value. Then, if the accumulated value of the input / output currents for a given period is a positive value, the control unit 52 can determine that the battery 11 is in a charged state, and if the accumulated value of the input / output currents for a given period is a negative value, the control unit 52 can determine that the battery 11 is in a discharged state. The given period can be, for example, the period from when the battery 11 has reached a specified storage capacity (e.g., SOC = 80%) to the present time at which the determination is made.

[0031] Furthermore, by using both the current input / output current of the battery 11 and the integrated value of the input / output current up to the present, it is possible to determine that the battery 11 is in a discharging state (requires charging) if, for example, the integrated value of the input / output current is a negative value even if current is flowing into the battery 11. Also, if the integrated value of the input / output current is a positive value, it is possible to determine that the battery 11 is in a charging state until the amount of charge drops to a specified level, even if current is flowing out of the battery 11.

[0032] If the control unit 52 determines that the battery 11 is in a discharging state (step S202, Yes), the process proceeds to step S203. On the other hand, if the control unit 52 determines that the battery 11 is not in a discharging state (step S202, No), the process proceeds to step S201.

[0033] (Step S203) The control unit 52 of the control device 50 puts the engine 30 into an operating state. Specifically, if the engine 30 is in a stopped state, the control unit 52 starts the engine 30 to operate, and if the engine 30 is already in an operating state, the control unit 52 keeps the engine 30 in that operating state. In addition, the control unit 52 prohibits the engine 30 from stopping at the same time as putting the engine 30 into an operating state. This prohibition of stopping the engine 30 can be controlled by setting a predetermined prohibition flag to ON, for example. Once the control unit 52 puts the engine 30 into an operating state, the process proceeds to step S204.

[0034] (Step S204) The control unit 52 of the control device 50 starts measuring the time that the engine 30 is operating (hereinafter referred to as "engine operating time"). This measurement starts using a predetermined time timer from the point in time when the processing of step S203 is completed. When the control unit 52 starts measuring the engine operating time, the processing proceeds to step S205.

[0035] (Step S205) The control unit 52 of the control device 50 starts power generation by the alternator 13. As a result, the power generated by the alternator 13 is supplied to the load 40 and the battery 11 together with the power output from the DC-DC converter 12. When the control unit 52 starts power generation by the alternator 13, the process proceeds to step S206.

[0036] (Step S206) The control unit 52 of the control device 50 determines whether the engine operating time has reached a first time. This determination is made to provide a timing for checking the state of the battery 11. Therefore, the first time is set to a predetermined time when it is desired to check again whether the battery 11 remains in a discharged state.

[0037] If the control unit 52 determines that the engine operation time has reached the first hour (YES in step S206), the process proceeds to step S207. On the other hand, if the control unit 52 determines that the engine operation time has not yet reached the first hour (NO in step S206), the alternator 13 continues generating electricity until the first hour is reached.

[0038] (Step S207) The control unit 52 of the control device 50 stops the power generation by the alternator 13. As a result, only the power output from the DC-DC converter 12 is supplied to the load 40 and the battery 11. When the power generation by the alternator 13 is stopped by the control unit 52, the process proceeds to step S208.

[0039] (Step S208) The control unit 52 of the control device 50 determines whether the integrated value of the input / output current of the battery 11 during the first hour is equal to or greater than the second threshold. Specifically, the control unit 52 sequentially integrates the input / output current of the battery 11 acquired by the acquisition unit 51 until the engine operation time reaches the first hour to calculate an integrated value (with a ± sign), and compares this calculated integrated value of the input / output current with the second threshold. This determination is made to determine whether the battery 11 remains in a discharged state. Therefore, the second threshold is set to a predetermined current amount that can determine that the battery 11 is no longer in a discharged state.

[0040] If the control unit 52 determines that the integrated value of the current flowing into and out of the battery 11 during the first hour is equal to or greater than the second threshold value (Yes in step S208), it is determined that power generation by the alternator 13 is unnecessary, and the process proceeds to step S209. On the other hand, if the control unit 52 determines that the integrated value of the current flowing into and out of the battery 11 during the first hour is less than the second threshold value (No in step S208), it is determined that power generation by the alternator 13 is still necessary, and the process proceeds to step S210.

[0041] (Step S209) The control unit 52 of the control device 50 permits the engine 30 to be stopped. This permission to stop the engine 30 can be controlled by, for example, setting a predetermined prohibition flag to OFF. When the control unit 52 permits the engine 30 to be stopped, this power control ends.

[0042] (Step S210) The control unit 52 of the control device 50 resets the engine operation time. As a result, the counting of the engine operation time starts again from 0. Once the engine operation time has been reset by the control unit 52, the process proceeds to step S204.

[0043] <Actions and Effects> As described above, according to the control device 50 of one embodiment of the present disclosure, when the battery 11 is in a discharging state outputting current to the load 40, the engine 30 is prohibited from stopping while it is running so that the alternator 13 can generate electricity using the engine 30.

[0044] By this control, when the power demand (current consumption) by the load 40 exceeds the supply capacity (output limit) of the DC-DC converter 12, the alternator 13 is made to generate power, so that the power supplied from the battery 11 to the load 40 can be switched to the power of the alternator 13. Therefore, the specified storage amount (control target amount) set in the battery 11 can be maintained without being affected by fluctuations in the power demand of the load 40.

[0045] Furthermore, according to the control device 50 of this embodiment, whether the battery 11 is in a discharged state can be determined using the detection value of the battery sensor originally installed in the vehicle, so that the above-mentioned power control can be realized at low cost without adding any new hardware configuration.

[0046] The above describes one embodiment of the present disclosure, but the present disclosure can be understood as not only a control device, but also a method executed by a control device equipped with a processor, memory, etc., a program for executing this method, a computer-readable non-transitory storage medium storing the program, and a vehicle equipped with a control device, etc. [Industrial Applicability]

[0047] The control device of the present disclosure can be used in vehicles equipped with a power supply system including a DC-DC converter and an alternator, particularly in vehicles in which the engine is stopped intermittently for purposes such as improving fuel efficiency and reducing emissions. [Explanation of symbols]

[0048] 10 Power System 11 Battery 12 DC-DC converter 13 Alternator 14 Sensors 20 Power supply source 30 Engine 40 Load 50 Control device 51 Acquisition Department 52 Control section

Claims

1. A control device for controlling a power supply system including a DC-DC converter that supplies power from a power supply source to a load, an alternator that is connected in parallel with the DC-DC converter so as to be able to supply power generated by rotation of an engine to the load, and a battery that is connected to the load so as to be able to supply power, an acquisition unit that acquires information about the current of the battery; a control unit that controls operations of the engine and the alternator based on the information, the control unit prohibits the engine from being stopped when the battery is in a discharging state in which the battery outputs a current to the load. Control device.

2. the control unit determines the discharge state of the battery based on a current inflow / outflow current of the battery obtained from the information and an integrated value of the current inflow / outflow current. The control device according to claim 1 .

3. When the battery is in the discharged state, the control unit permits the engine to be stopped if the battery is no longer in the discharged state after the alternator has generated power for a first hour. The control device according to claim 1 or 2.

4. the control unit determines that the battery is not in the discharged state when an integrated value of the inflow / outflow current of the battery during the first time period is equal to or greater than a second threshold value; The control device according to claim 3 .

Images