JP2017100472A - Charge control device for hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charge control device for a hybrid vehicle that can prevent a decline in electrical power supplied to an electric load connected to a second power storage device.SOLUTION: ECM 11 of a vehicle 1 determines whether to re-start an engine 2 based on discharge capacity of the second power storage device 31 and an amount of electric power consumption of a protected load 38 and re-starts the engine 2 by driving ISG 20 when the amount of electric power consumption of the protected load 38 exceeds the discharge capacity of the second power storage device 31.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a charging control device for a hybrid vehicle.

  In a hybrid vehicle that travels using an internal combustion engine and a motor generator driven by power supplied from a battery as a drive source, the battery is connected to the battery when the load on the battery is large, such as when the internal combustion engine is started. There is a possibility that a temporary decrease in power supply or a momentary power interruption may occur with respect to the electrical load.

  As a conventional hybrid vehicle control device, when it is determined that the load of the secondary battery is large during the start-up process of the internal combustion engine, the discharge power necessary for starting the internal combustion engine is secured and connected to the secondary battery. What protects an electrical component is known (for example, refer patent document 1).

JP2013-126825A

  However, in such a conventional hybrid vehicle control device, the discharge capacity is reduced due to the temperature characteristics of the secondary battery, and the load on the electrical components connected to the secondary battery is increased. Thus, no countermeasure has been taken for the possibility that the power supply to the electrical components connected to the secondary battery is reduced.

  An object of the present invention is to provide a charging control device for a hybrid vehicle that can prevent power supplied to an electric load connected to a second power storage device from decreasing.

  The present invention includes a starting device for starting an internal combustion engine, a first power storage device that supplies power for driving at least the starting device, a second power storage device that supplies power for operating an electric load, A charge control device for a hybrid vehicle, comprising: a power generation device that generates power based on power of an internal combustion engine; and a motor generator, wherein the second power storage device is a hybrid vehicle that travels using at least one of the internal combustion engine and the motor generator as a drive source. A discharge capacity estimating unit that estimates the discharge capacity of the second power storage device based on the state of charge of the battery and the temperature of the second power storage device, and estimating the power consumption of the electric load from the amount of electric load of the electric load The internal combustion engine based on a power consumption estimation unit, a discharge capability estimated by the discharge capability estimation unit, and a power consumption estimated by the power consumption estimation unit It determines whether to start the configured to include an internal combustion engine start control unit for starting the internal combustion engine by the starting device based on the determination result.

  ADVANTAGE OF THE INVENTION According to this invention, it can prevent that the electric power supplied to the electrical load connected to a 2nd electrical storage apparatus falls.

FIG. 1 is a schematic configuration diagram of a hybrid vehicle including a charge control device according to an embodiment of the present invention. FIG. 2 is a system configuration diagram of a charging control apparatus for a hybrid vehicle according to an embodiment of the present invention. FIG. 3 is a flowchart of the charging control process for the hybrid vehicle according to the embodiment of the present invention.

Embodiments of a charging control device for a hybrid vehicle according to the present invention will be described below with reference to the drawings.
1 to 3 are diagrams showing a charge control device for a hybrid vehicle according to an embodiment of the present invention.

First, the configuration will be described.
In FIG. 1, a hybrid vehicle (hereinafter simply referred to as a vehicle) 1 is an engine 2 as an internal combustion engine, a transmission 3, a motor generator 4, drive wheels 5, and a vehicle control unit that comprehensively controls the vehicle 1. HCM (Hybrid Control Unit) 10, ECM (Engine Control Module) 11 for controlling the engine 2, TCM (Transmission Control Module) 12 for controlling the transmission 3, ISGCM (Integrated Starter Generator Control Module) 13, and INVCM (Invertor Control Module) 14, a low voltage BMS (Battery Management System) 15, and a high voltage BMS 16 are included.

  The engine 2 is formed with a plurality of cylinders. In the present embodiment, the engine 2 is configured to perform a series of four strokes including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke for each cylinder.

  The engine 2 is connected with an ISG (Integrated Starter Generator) 20 and a starter 21. The ISG 20 is connected to the crankshaft 18 of the engine 2 via a belt 22 or the like. The ISG 20 has a function of an electric motor that starts the engine 2 by rotating when supplied with electric power, and a function of a generator that converts rotational force input from the crankshaft 18 into electric power.

  In this embodiment, the ISG 20 restarts the engine 2 from a stop state by the idling stop function by functioning as an electric motor under the control of the ISGCM 13. The ISG 20 assists the traveling of the vehicle 1 by functioning as an electric motor. The ISG 20 of the present embodiment constitutes the power generator and starter of the present invention.

  The starter 21 includes a motor and a pinion gear (not shown). The starter 21 rotates the crankshaft 18 by rotating the motor, and gives the engine 2 a starting torque. As described above, the engine 2 is started by the starter 21 and restarted by the ISG 20 from the stop state by the idling stop function.

  The transmission 3 shifts the rotation output from the engine 2 and drives the drive wheels 5 via the drive shaft 23. The transmission 3 includes a constantly meshing transmission mechanism 25 composed of a parallel shaft gear mechanism, a clutch 26 constituted by a dry single-plate clutch, a differential mechanism 27, and an actuator (not shown).

  The transmission 3 is configured as a so-called AMT (Automated Manual Transmission), and functions as an automatic transmission that switches gears in the transmission mechanism 25 and engages / disengages the clutch 26 by an actuator controlled by the TCM 12. The differential mechanism 27 transmits the power output by the speed change mechanism 25 to the drive shaft 23.

The motor generator 4 is connected to the differential mechanism 27 via a power transmission mechanism 28 such as a chain. That is, the motor generator 4 is connected to a power transmission path from the transmission 3 to the drive wheels 5.
The motor generator 4 functions as an electric motor and is driven by electric power supplied from the third power storage device 33.

  Thus, the vehicle 1 forms a parallel hybrid system that can use the power of both the engine 2 and the motor generator 4 for driving the vehicle. The vehicle 1 travels with power generated by at least one of the engine 2 and the motor generator 4.

  The vehicle 1 travels using only the engine torque generated by the engine 2, travels using only the motor torque generated by the motor generator 4 (EV travel), and travel that assists the engine torque of the engine 2 by powering the motor generator 4. (Assist driving) is possible. Thus, the vehicle 1 has an EV traveling function and an assist traveling function.

  The motor generator 4 also functions as a generator, and generates power when the vehicle 1 travels. The motor generator 4 may be connected to any part of the power transmission path from the engine 2 to the drive wheel 5 so as to be able to transmit power, and is not necessarily connected to the differential mechanism 27.

  The vehicle 1 includes a first power storage device 30, a low voltage power pack 32 including a second power storage device 31, a high voltage power pack 34 including a third power storage device 33, a high voltage cable 35, and a low voltage cable 36. It has.

  The first power storage device 30, the second power storage device 31, and the third power storage device 33 are composed of rechargeable secondary batteries. First power storage device 30 is formed of a lead battery. The second power storage device 31 is a power storage device with higher output and higher energy density than the first power storage device 30.

  The second power storage device 31 can be charged in a shorter time than the first power storage device 30. In the present embodiment, second power storage device 31 is formed of a lithium ion battery. The second power storage device 31 may be a nickel hydride storage battery.

  The first power storage device 30 and the second power storage device 31 are low voltage batteries in which the number of cells and the like are set so as to generate an output voltage of about 12V. The 3rd electrical storage apparatus 33 consists of a lithium ion battery, for example.

The third power storage device 33 is a high voltage battery in which the number of cells and the like are set so as to generate a higher voltage than the first power storage device 30 and the second power storage device 31. The state such as the remaining capacity of the third power storage device 33 is managed by the high voltage BMS 16.
The vehicle 1 is provided with a general load 37 and a protected load 38 as electric loads. The general load 37 and the protected load 38 are electric loads other than the starter 21 and the ISG 20.

  The protected load 38 is an electric load that always requires a stable power supply. The protected load 38 includes a stability control device 38A that prevents a side slip of the vehicle, an electric power steering control device 38B that electrically assists the operating force of the drive wheels 5, and a headlight 38C. The protected load 38 also includes instrument panel lamps and meters (not shown), a car navigation system, and the like. The protected load 38 of the present embodiment constitutes an electrical load of the invention.

  The general load 37 is an electric load that is temporarily used without requiring stable power supply as compared with the protected load 38. The general load 37 includes, for example, an unillustrated wiper and an electric cooling fan that blows cooling air to the engine 2.

  The low voltage power pack 32 includes switches 40 and 41 and a low voltage BMS 15 in addition to the second power storage device 31. First power storage device 30 and second power storage device 31 are connected to starter 21, ISG 20, general load 37 as an electrical load, and protected load 38 via low voltage cable 36 so as to be able to supply power. Yes. The first power storage device 30 and the second power storage device 31 are electrically connected in parallel to the protected load 38.

  The switch 40 is provided in the low voltage cable 36 between the second power storage device 31 and the protected load 38. The switch 41 is provided in the low voltage cable 36 between the first power storage device 30 and the protected load 38.

  The low voltage BMS 15 controls charging / discharging of the second power storage device 31 and power supply to the protected load 38 by controlling opening and closing of the switches 40 and 41.

  When the engine 2 is stopped due to idling stop, the low voltage BMS 15 closes the switch 40 and opens the switch 41, so that power is supplied from the second power storage device 31 having high output and high energy density to the protected load 38. Supply.

  When the engine 2 is started by the starter 21 and when the engine 2 stopped by the idling stop control is started by the ISG 20, the low voltage BMS 15 opens the switch 41 after closing the switch 40. Electric power is supplied from the power storage device 30 to the starter 21 or the ISG 20. In a state where the switch 40 is closed and the switch 41 is opened, power is also supplied from the first power storage device 30 to the general load 37.

  Thus, the first power storage device 30 supplies power to the ISG 20 and the starter 21 that start the engine 2. The second power storage device 31 supplies power to the general load 37 and the protected load 38.

  The second power storage device 31 is connected so as to be able to supply power to both the general load 37 and the protected load 38. However, the second power storage device 31 preferentially supplies power to the protected load 38 that always requires stable power supply. Thus, the switches 40 and 41 are controlled by the low voltage BMS 15.

  The low voltage BMS 15 is a charge state of the first power storage device 30 and the second power storage device 31 (also referred to as SOC: State Of Charge, remaining charge amount or charge capacity), and an operation request to the general load 37 and the protected load 38. In consideration of the above, the switches 40 and 41 may be controlled differently from the above-described example in order to prioritize that the protected load 38 operates stably.

  The high voltage power pack 34 includes an inverter 45, INVCM 14, and high voltage BMS 16 in addition to the third power storage device 33. The high voltage power pack 34 is connected to the motor generator 4 via a high voltage cable 35 so that electric power can be supplied.

  The inverter 45 mutually converts AC power applied to the high voltage cable 35 and DC power applied to the third power storage device 33 under the control of the INVCM 14. For example, when powering the motor generator 4, the INVCM 14 converts the DC power discharged by the third power storage device 33 into AC power by the inverter 45 and supplies the AC power to the motor generator 4.

  When the motor generator 4 is regenerated, the INVCM 14 converts the AC power generated by the motor generator 4 into DC power by the inverter 45 and charges the third power storage device 33.

  HCU10, ECM11, TCM12, ISGCM13, INVCM14, low voltage BMS15 and high voltage BMS16 are respectively CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), backup data, etc. The computer unit includes a flash memory to be stored, an input port, and an output port.

  ROMs of these computer units store various constants, various maps, and the like, and programs for causing the computer units to function as the HCU 10, ECM 11, TCM 12, ISGCM 13, INVCM 14, low voltage BMS 15 and high voltage BMS 16, respectively. .

  That is, when the CPU executes a program stored in the ROM using the RAM as a work area, these computer units are used as the HCU 10, ECM 11, TCM 12, ISGCM 13, INVCM 14, low voltage BMS 15 and high voltage BMS 16 in the present embodiment. Each functions.

In the present embodiment, the ECM 11 performs idling stop control. In the idling stop control, for example, the ECM 11 stops the engine 2 when a predetermined stop condition is satisfied, and restarts the engine 2 by driving the ISG 20 via the ISGCM 13 when the predetermined restart condition is satisfied. For this reason, unnecessary idling of the engine 2 is not performed, and the fuel consumption of the vehicle 1 can be improved.
As described above, the vehicle 1 has an IS (Idling Stop) function for performing idling stop under a predetermined condition.

The vehicle 1 is provided with CAN communication lines 48 and 49 for forming an in-vehicle LAN (Local Area Network) conforming to a standard such as CAN (Controller Area Network).
The HCU 10 is connected to the INVCM 14 and the high voltage BMS 16 by a CAN communication line 48. The HCU 10, INVCM 14 and high voltage BMS 16 mutually transmit and receive signals such as control signals via the CAN communication line 48.

  The HCU 10 is connected to the ECM 11, the TCM 12, the ISGCM 13 and the low voltage BMS 15 by a CAN communication line 49. The HCU 10, ECM 11, TCM 12, ISGCM 13, and low voltage BMS 15 mutually transmit and receive signals such as control signals via the CAN communication line 49. The HCU 10 controls the engine 2, the TCM 12, and the motor generator 4 by transmitting and receiving signals such as control signals.

In FIG. 2, the vehicle 1 is provided with a temperature detection unit 55, a charge state detection unit 56, and a load amount detection unit 57.
The temperature detection unit 55 detects the temperature of the second second power storage device 31 and outputs the detection result to the ECM 11.

  The charging state detection unit 56 detects the charging state of the second power storage device 31 and outputs the detection result to the ECM 11. The charging state detection unit 56 detects the charging state of the second power storage device 31 by detecting the voltage between the terminals of the second power storage device 31 or by detecting the input / output current of the second power storage device 31.

The load amount detection unit 57 detects the electrical load amount of the protected load 38 and outputs the detection result to the ECM 11. The electrical load amount is a current value applied to the protected load 38.
The electrical load amount of the protected load 38 depends on the traveling state of the vehicle 1. For example, in the electric power steering control device 38B that electrically assists the operating force of the drive wheels 5, the amount of electric load during meandering travel is greater than when the vehicle 1 is traveling straight.

The ECM 11 functions as a discharge capacity estimation unit 58, a power consumption estimation unit 59, and an engine start control unit 60.
The discharge capacity estimation unit 58 discharges the second power storage device 31 based on the charge state of the second power storage device 31 acquired from the charge state detection unit 56 and the temperature information of the second power storage device 31 acquired from the temperature detection unit 55. Estimate ability. For example, the discharge capacity estimation unit 58 estimates the discharge capacity of the second power storage device 31 with reference to a map or the like in which the state of charge of the second power storage device 31 and the temperature information of the second power storage device 31 are associated.

The power consumption estimation unit 59 estimates the power consumption of the protected load 38 from the electrical load amount of the protected load 38 input from the load amount detection unit 57.
The engine start control unit 60 determines whether or not to restart the engine 2 based on the discharge capacity estimated by the discharge capacity estimation unit 58 and the power consumption estimated by the power consumption estimation unit 59.

Further, the engine start control unit 60 drives the ISG 20 to restart the engine 2 on the condition that it is determined that the engine 2 is restarted.
Specifically, when the power consumption estimated by the power consumption estimation unit 59 exceeds the discharge capability estimated by the discharge capability estimation unit 58, the ECM 11 drives the ISG 20 to restart the engine 2. The engine start control unit 60 of the present embodiment constitutes an internal combustion engine start control unit of the present invention. Further, the ECM 11 of the present embodiment constitutes the charge control device of the present invention.

The power consumption estimation unit 59 stores a threshold that is determined based on the power consumption of the protected load 38. The engine start control unit 60 drives the ISG 20 to start the engine 2 when the discharge capacity estimated by the discharge capacity estimation unit 58 falls below a threshold value determined based on the power consumption of the protected load 38.
Note that the threshold value determined based on the power consumption amount may be set to increase as the electrical load amount of the protected load 38 detected by the load amount detection unit 57 increases.

Next, the operation will be described.
FIG. 3 is a flowchart of the charge control process of the vehicle 1, and this charge control process is executed by a charge control process program stored in the ECM 11.

  In FIG. 3, the ECM 11 acquires the charge state of the second power storage device 31 based on the detection information from the charge state detection unit 56, and uses the temperature information of the second power storage device 31 based on the detection information of the temperature detection unit 55. Obtain (step S1).

  Next, the ECM 11 estimates the discharge capacity of the second power storage device 31 based on the state of charge of the second power storage device 31 and the temperature information (step S2). Next, the ECM 11 acquires the electrical load amount of the protected load 38 based on the detection information of the load amount detection unit 57 (step S3), and estimates the power consumption amount of the protected load 38 based on this electrical load amount. (Step S4).

  Next, the ECM 11 compares the discharge capacity of the second power storage device 31 with the power consumption of the protected load 38 (step S5), and the discharge capacity of the second power storage device 31 is greater than or equal to the power consumption of the protected load 38. If it is determined that the power is large, it is determined that the power stored in the second power storage device 31 is sufficient with respect to the power consumption of the protected load 38 (step S6), and the current process is performed. finish.

  In step S5, if the ECM 11 determines that the discharge capacity of the second power storage device 31 is smaller than the power consumption of the protected load 38, the power stored in the second power storage device 31 is insufficient. (Step S7). In step 5, if the discharge capacity of the second power storage device 31 falls below a threshold determined based on the power consumption, the ECM 11 has a shortage of power stored in the second power storage device 31. to decide.

  If the ECM 11 determines that the power stored in the second power storage device 31 is insufficient, the ECM 11 determines whether or not the engine 2 is stopped (step S8), and the engine 2 is not stopped. If it is determined that it is, the current process is terminated. Note that while the engine 2 is stopped, the vehicle 1 is shifted to EV traveling only by the motor torque generated by the motor generator 4.

On the other hand, if the ECM 11 determines that the engine 2 is stopped, the ISG 20 is driven to restart the engine 2 (step S9), and then the current process is terminated. When the engine 2 is restarted, power is supplied from the first power storage device 30 to the ISG 20 by the switch 41 being opened after the switch 40 is closed by the low voltage BMS 15.
Then, after starting the engine 2, the switch 41 is closed by the low voltage BMS 15, whereby electric power is supplied from the ISG 20 to the first power storage devices 30 and 31.

  As described above, the ECM 11 of the vehicle 1 according to the present embodiment determines whether or not to restart the engine 2 based on the discharge capacity of the second power storage device 31 and the power consumption of the protected load 38, and is protected. When the power consumption of the load 38 exceeds the discharge capacity of the second power storage device 31, the ISG 20 is driven to restart the engine 2.

  Thereby, at the time of restart of the engine 2, it can prevent that the electric power supplied to the protected load 38 connected to the 2nd electrical storage apparatus 31 falls. In the electric power steering control device 38B that electrically assists the operating force of the drive wheels 5, the electric load amount during meandering travel is larger than when the vehicle 1 travels linearly. Electric power can be stably supplied to the control device 38B.

  Further, since the ECM 11 drives the ISG 20 and restarts the engine 2 when the discharge capacity of the second power storage device 31 falls below a threshold value determined based on the power consumption of the protected load 38, the engine 2 is restarted. At the time of restarting, it is possible to more effectively prevent the power supplied to the protected load 38 connected to the second power storage device 31 from being lowered.

  Furthermore, the ECM 11 can increase the engine timing at an earlier timing when the electrical load amount of the protected load 38 is high by increasing the threshold value determined based on the power consumption as the electrical load amount of the protected load 38 increases. 2 can be restarted and power generation by the ISG 20 can be performed at an early stage.

  Thereby, at the time of restart of the engine 2, it can prevent more effectively that the electric power supplied to the to-be-protected load 38 connected to the 2nd electrical storage apparatus 31 falls.

  For example, in the electric power steering control device 38B, since the electric load amount during meandering is larger than the electric load amount during straight running of the vehicle 1, the power consumption of the protected load 38 when the vehicle 1 meanders. Becomes larger.

Therefore, if the threshold value determined based on the power consumption is increased as the electrical load amount of the protected load 38 is increased, power generation by the ISG 20 can be performed earlier.
In addition, although the vehicle 1 of this Embodiment uses ISG20 as a power generator, you may use an alternator as a power generator.

  While embodiments of the invention have been disclosed, it will be apparent to those skilled in the art that changes may be made without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims.

  1 ... hybrid vehicle, 2 ... engine (internal combustion engine), 4 ... motor generator, 10 ... ECM (charge control device), 20 ... ISG (starting device, power generation device), 30. ..First power storage device, 31 ... second power storage device, 38 ... protected load (electric load), 55 ... temperature detection unit, 56 ... charge state detection unit, 57 ... load Quantity detection unit, 58 ... Discharge capacity estimation unit, 59 ... Electricity consumption estimation unit, 60 ... Engine start control unit (internal combustion engine start control unit)

Claims (4)

A starting device for starting the internal combustion engine, a first power storage device that supplies at least electric power for driving the starting device, a second power storage device that supplies electric power for operating an electric load, and the power of the internal combustion engine A power generator that generates power based on the motor generator,
A charge control device for a hybrid vehicle that travels using at least one of the internal combustion engine and the motor generator as a drive source,
A discharge capacity estimating unit that estimates a discharge capacity of the second power storage device based on a charge state of the second power storage device and a temperature of the second power storage device;
A power consumption estimation unit that estimates the power consumption of the electrical load from the electrical load of the electrical load;
It is determined whether to start the internal combustion engine based on the discharge capacity estimated by the discharge capacity estimation unit and the power consumption estimated by the power consumption estimation unit, and based on the determination result, the start A charging control device for a hybrid vehicle, comprising: an internal combustion engine start control unit that drives the device to start the internal combustion engine.   The internal combustion engine start control unit drives the starter to start the internal combustion engine when the power consumption estimated by the power consumption estimation unit exceeds the discharge capability estimated by the discharge capability estimation unit. The charge control apparatus for a hybrid vehicle according to claim 1.   The internal combustion engine start control unit drives the starter to start the internal combustion engine when the discharge capacity estimated by the discharge capacity estimation unit falls below a threshold value determined based on the power consumption. The charging control device for a hybrid vehicle according to claim 1 or 2, wherein the charging control device is a hybrid vehicle.   4. The charging control for a hybrid vehicle according to claim 3, wherein the internal combustion engine start control unit increases the threshold value determined based on the power consumption amount as the electric load amount of the electric load increases. apparatus.