JP2017114322A - Hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hybrid vehicle capable of extending a staying time in an EV travel mode to enhance fuel economy.SOLUTION: Hybrid vehicle 1 comprises switches 40, 41 for forming either of a first connection state in which a first power storage device 30 and a second power storage device 31 are connected in parallel to an ISG 20 or a second connection state in which the first power storage device 30 is connected to the ISG20. Upon determining that the first power storage device 30 or the second power storage device 31 needs to be charged according to a charge state detected by a first charge state detection part and a second charge state detection part, a power generation control part sets the switches 40, 41 to the first connection state, and makes the ISG20 to generate the power. Then, when the second power storage device 31 becomes fully charged, the power control part sets the switches 40, 41 to the second connection state, and makes the ISG 20 to continue to generate the power.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hybrid vehicle.

  The hybrid vehicle includes an engine and a motor generator that is driven by electric power supplied from a battery as a drive source, and travels by the power of at least one of the engine or the motor generator.

  As a conventional hybrid vehicle, one described in Patent Document 1 is known. In the hybrid vehicle described in Patent Document 1, a lead battery and a lithium ion battery are connected in parallel to the generator, and the conduction state between these batteries is switched and the generated voltage of the generator is adjusted. Thus, the power supply to the electric load can be suitably performed.

JP 2014-033571 A

  Here, in a hybrid vehicle capable of EV traveling, in an EV state in which EV traveling is possible (EV traveling mode), the engine is stopped, and in addition to not consuming fuel, engine noise is generated. Therefore, comfort, quietness and fuel efficiency can be improved. For this reason, it is desirable to extend the time for executing the EV traveling mode. In order to execute the EV traveling mode, it is necessary that the state of charge of the battery that supplies power to the vehicle system is good.

  However, the hybrid vehicle described in Patent Document 1 does not consider maintaining EV travel longer. For this reason, there existed a problem that the residence time of EV driving mode could not be extended or a fuel consumption could not be improved.

  The present invention extends the staying time in the EV traveling mode by controlling the connection state and the power generation state of the batteries so that the capacity of a plurality of batteries installed for supplying electric power to the electric load can be utilized to the maximum extent. The aim is to improve fuel economy.

  One aspect of the invention of a hybrid vehicle that solves the above problem is a hybrid vehicle that includes an engine and a motor generator as drive sources, and that travels by power output from at least one of the engine and the motor generator. A power generator for generating power, a first battery and a second battery having different characteristics, a charge state detector for detecting a charge state of each of the first battery and the second battery, and the generator A connection switch that forms one of a first connection state in which the first battery and the second battery are connected in parallel and a second connection state in which the first battery is connected to the generator; A power generation control unit that controls a power generation state of the generator and a connection state of the connection switch, and the power generation control. If it is determined that charging of the first battery or the second battery is necessary based on the charging state detected by the charging state detection unit, the generator is configured to generate power after setting the connection switch to the first connection state. When the second battery is fully charged, the generator is caused to continue power generation after the connection switch is set to the second connection state.

  According to the present invention, the staying time in the EV traveling mode can be extended and the fuel consumption can be improved.

FIG. 1 is a diagram illustrating a hybrid vehicle according to an embodiment of the present invention, and is a configuration diagram of the hybrid vehicle. FIG. 2 is a diagram illustrating a hybrid vehicle according to an embodiment of the present invention, and is a configuration diagram of a low-voltage system of the hybrid vehicle. FIG. 3 is a diagram illustrating charging characteristics of the first power storage device and the second power storage device in the hybrid vehicle according to the embodiment of the present invention. FIG. 4 is a flowchart showing the flow of the first charging process by the hybrid vehicle according to the embodiment of the present invention. FIG. 5 is a flowchart showing the flow of the second charging process by the hybrid vehicle according to the embodiment of the present invention. FIG. 6 is a timing chart when the first charging process and the second charging process are executed in the hybrid vehicle according to the embodiment of the present invention. FIG. 7 is a timing chart when the second charging process is executed in the time reduction mode in the hybrid vehicle according to the embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings. Hereinafter, a vehicle equipped with a drive control device according to an embodiment of the present invention will be described.

  As shown in FIG. 1, the hybrid vehicle 1 includes an engine 2 as an internal combustion engine, a transmission 3, a motor generator 4, drive wheels 5, and an HCU (Hybrid Control Unit) that comprehensively controls the hybrid vehicle 1. 10, an ECM (Engine Control Module) 11 that controls the engine 2, a TCM (Transmission Control Module) 12 that controls the transmission 3, an ISGCM (Integrated Starter Generator Control Module) 13, and an INVCM (Invertor Control Module) 14 And a low voltage BMS (Battery Management System) 15 and a high voltage BMS 16.

  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 is configured to restart the engine 2 from a stopped state by the idling stop function by functioning as an electric motor under the control of the ISGCM 13. The ISG 20 can also assist the traveling of the hybrid vehicle 1 by functioning as an electric motor.

  The starter 21 includes a motor and a pinion gear (not shown). The starter 21 rotates the crankshaft 18 by rotating the motor to give 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 an always-meshing transmission mechanism 25 including a parallel shaft gear mechanism, a clutch 26 including a dry single-plate clutch, a differential mechanism 27, a clutch actuator 51, and a shift actuator 52. Yes.

  The clutch actuator 51 is configured to connect and disconnect (disconnect and connect) the clutch 26 under the control of the TCM 12. The shift actuator 52 switches a gear position by moving a shift sleeve (not shown) of the transmission mechanism 25 under the control of the TCM 12. Hereinafter, switching the gear stage by disengaging the clutch 26 is also simply referred to as shifting.

  As described above, the transmission 3 is configured as an automatic transmission called AMT (Automated Manual Transmission) that can automatically shift gears under the control of the TCM 12. The differential mechanism 27 is configured to transmit 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. The motor generator 4 functions as an electric motor.

  Thus, the hybrid 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 hybrid vehicle 1 travels with power generated by at least one of the engine 2 and the motor generator 4.

  The hybrid vehicle 1 assists the engine torque of the engine 2 by using only the engine torque generated by the engine 2, traveling only by the motor torque generated by the motor generator 4 (EV traveling), and using the motor torque as an assist torque. Travel (assist travel) is possible. Thus, the hybrid vehicle 1 has an EV travel function and an assist travel function.

  The motor generator 4 also functions as a generator and generates power when the hybrid vehicle 1 travels. The motor generator 4 may be connected to any part of the power transmission path from the transmission 3 to the drive wheel 5 so as to be able to transmit power, and is not necessarily connected to the differential mechanism 27.

  The hybrid 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. And.

  The 1st electrical storage apparatus 30, the 2nd electrical storage apparatus 31, and the 3rd electrical storage apparatus 33 are comprised from the rechargeable secondary battery. 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 this embodiment, the 2nd electrical storage apparatus 31 consists 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 is set so as to generate an output voltage of about 12V. The 3rd electrical storage apparatus 33 consists of a nickel hydride storage battery or a lithium ion battery, for example.

  The third power storage device 33 is a high voltage battery in which the number of cells is set so as to generate a higher voltage than the first power storage device 30 and the second power storage device 31, and generates an output voltage of 100V, for example. The state such as the remaining capacity of the third power storage device 33 is managed by the high voltage BMS 16.

  The hybrid 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 steering wheel, and a headlight 38C. The protected load 38 also includes instrument panel lamps and meters (not shown) and a car navigation system.

  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, a wiper (not shown) 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. The first power storage device 30 and the second power storage device 31 are connected to the starter 21, the ISG 20, the general load 37 as an electrical load, and the protected load 38 via a 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, thereby supplying power from the second power storage device 31 having high output and high energy density to the protected load 38. It comes to supply.

  When the engine 2 is started by the starter 21 and when the engine 2 stopped by the idling stop control is restarted by the ISG 20, the low voltage BMS 15 opens the switch 41 and opens the switch 41. Electric power is supplied from the power storage device 30 to the starter 21 or the ISG 20. When 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.

  As described above, the first power storage device 30 supplies at least electric power to the starter 21 and the ISG 20 as starters for starting the engine 2. The second power storage device 31 supplies at least 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 charged to the first power storage device 30 and the second power storage device 31 (also referred to as SOC: State Of Charge, power storage state, remaining charge amount, charge capacity), and to the general load 37 and the protected load 38. The switches 40 and 41 may be controlled differently from the above-mentioned example in consideration of the operation requirements of the above, giving priority to stable operation of the protected load 38.

  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 is configured to mutually convert 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. Is constituted by a computer unit having a flash memory for storing, an input port, and an output port.

  The ROMs of these computer units store various constants and maps, 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. Yes.

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

  In the present embodiment, the ECM 11 performs idling stop control. In this idling stop control, 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 efficiency of the hybrid vehicle 1 can be improved.

  In the present embodiment, the ECM 11 stops the engine 2 with a predetermined stop condition that the vehicle is in a stopped state (the vehicle speed is zero). Thus, the hybrid vehicle 1 is provided with a stop IS (Idling Stop) function that performs idling stop when the vehicle stops. When the vehicle is stopped by the idling stop on the uphill road where the road surface state is inclined, the electric motor function of the motor generator 4 is used to maintain the stopped state of the vehicle. Maintenance of the stop state of the vehicle by the motor generator 4 is performed using the electric power of the third power storage device 33.

  The hybrid 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 hybrid vehicle 1 of this embodiment has a gap filling function. The gap filling function is a function of driving the motor generator 4 during the shift of the transmission 3 and applying the torque of the motor generator 4 to the drive wheels 5.

  The HCU 10 implements the gap filling function by executing the gap filling control operation when the operation is permitted. While the transmission 3 is shifting, the clutch 26 is disengaged and engine torque cannot be transmitted from the engine 2 to the drive wheels 5. For this reason, the HCU 10 applies the motor torque (assist torque) generated by the power running operation of the motor generator 4 to the drive wheels 5 in the gap filling control operation. By this gap filling function, the feeling of deceleration due to the disengagement of the clutch 26 during the shift is suppressed, and the running performance of the vehicle can be improved.

  In FIG. 2, the hybrid vehicle 1 includes a first charging state detection unit 61, which detects the charging state of the first power storage device 30 and outputs a detection signal to the HCU 10. . The first charge state detection unit 61 is provided in the vicinity of the first power storage device 30, and detects the voltage between the terminals of the first power storage device 30 and the input / output current to the first power storage device 30, thereby The state of charge of power storage device 30 is detected.

  The hybrid vehicle 1 also includes a second charge state detection unit 62, which detects the charge state of the second power storage device 31 and outputs a detection signal to the HCU 10. The second charge state detection unit 62 is provided in the vicinity of the second power storage device 31, and detects the voltage between the terminals of the second power storage device 31 and the input / output current to the second power storage device 31, thereby The state of charge of the power storage device 31 is detected. The second charge state detection unit 62 outputs a detection signal to the HCU 10 via the low voltage BMS 15.

  The 1st charge condition detection part 61 and the 2nd charge condition detection part 62 comprise the charge condition detection part in this invention. Moreover, the 1st electrical storage apparatus 30 comprises the 1st battery in this invention, and the 2nd electrical storage apparatus 31 comprises the 2nd battery in this invention.

  The low voltage cable 36 is branched into two between the first power storage device 30 and the second power storage device 31. One of the branch portions of the low-voltage cable 36 is provided with the above-described switch 41 and a fuse in series. A switch 42 and a fuse are provided on the other branch of the low voltage cable 36. Here, as described later, the open / close states of the switch 41 and the switch 42 are controlled to be equal to each other. For example, when the switch 41 is closed, the switch 42 is also closed. For this reason, the switch 42 is omitted in FIG.

  The general load 37 includes, for example, a blower fan, a radiator fan, an electric water pump, an electric negative pressure pump, an indoor lamp, and the like in addition to the wiper and the electric cooling fan described above.

The protected load 38 includes, in addition to the above-described stability control device 38A, electric power steering control device 38B, and headlight 38C, navigation (car navigation system), audio, meter, air conditioning panel, steering angle sensor, stereo camera, etc. Is included.
Is included.

  Here, the first connection state is formed when all of the switches 40, 41, and 42 described above are in the closed state. This first connection state is a state in which the first power storage device 30 and the second power storage device 31 are connected in parallel to the ISG 20 as a generator.

  In addition, the second connection state is formed when the switch 40 is in a connected state (closed state) and the switches 41 and 42 are in a disconnected state (open state) among the switches 40, 41, and 42. This second connection state is a state in which the first power storage device 30 is connected to the ISG 20 as a generator. The switches 40, 41, and 42 constitute a connection switch in the present invention.

  In the present embodiment, the HCU 10 includes a power generation control unit 10A, and the power generation control unit 10A controls the power generation state of the ISG 20 and the connection states of the switches 40, 41, and 42. Note that the actual switching of these switches 40, 41, 42 is performed by the low voltage BMS 15 in response to a switching request from the power generation control unit 10 </ b> A of the HCU 10 to the low voltage BMS 15.

  When the power generation control unit 10A determines that charging of the first power storage device 30 or the second power storage device 31 is necessary based on the charge state detected by the first charge state detection unit 61 and the second charge state detection unit 62, the switch 40, 41 and 42 are set to the first connection state, and then the ISG 20 is caused to start power generation.

  After that, when the second power storage device 31 is fully charged, the power generation control unit 10A causes the ISG 20 to continue power generation after setting the switches 40, 41, and 42 to the second connection state.

  Thereby, charge of the 1st electrical storage apparatus 30 is continued. When continuing to charge the first power storage device 30, the power generation control unit 10 </ b> A sets the power generation voltage of the ISG 20 to an upper limit voltage that can charge the first power storage device 30. Note that the power generation control unit 10 </ b> A may be provided in the ECM 30 instead of the HCU 10.

  Here, the difference in battery characteristics between the first power storage device 30 made of a lead battery and the second power storage device 31 made of a lithium ion battery will be described in detail.

  There are the following characteristic differences between the first power storage device 30 and the second power storage device 31.

  Regarding the battery voltage at the time of full charge, there is a difference in characteristics that the second power storage device 31 made of a lithium ion battery is lower than the first power storage device 30 made of a lead battery.

  Regarding the internal resistance of the battery, there is a difference in characteristics that the second power storage device 31 made of a lithium ion battery is lower than the first power storage device 30 made of a lead battery.

  For this reason, regarding the time required for full charge, the second power storage device 31 made of a lithium ion battery is shorter (faster) than the first power storage device 30 made of a lead battery.

  Therefore, when charging is started simultaneously with the first power storage device 30 and the second power storage device 31 connected in parallel to the ISG 20, the second power storage device 31 (denoted as Li in the drawing) as shown in FIG. Is fully charged before the first power storage device 30 (indicated as a lead battery in the figure).

  Here, FIG. 3 shows the amount of charge (charge amount) of the first power storage device 30 and the second power storage device 31 when discharged at 50% of capacity and then charged at a constant voltage of 25 ° C. and 13 V. .

  In FIG. 3, the second power storage device 31 reaches 100% of the amount of charged electricity at time t1. On the other hand, in the first power storage device 30, the amount of charge has reached 100% at time t2 after time t1.

  Moreover, since the voltage of a single cell of a lithium ion battery is 2.3V (lower limit voltage 1.5V, upper limit voltage 3.3V), the voltage in the case of a 4-cell assembled battery is 9.2V, The 12V power supply voltage range (6V to 14V) is the closest. Moreover, the upper voltage in the case of a 4-cell battery pack is 13.5V.

  For this reason, it is necessary to charge the second power storage device 31 so that it does not become 13.5 V or higher.

  The charging operation executed in the hybrid vehicle configured as described above will be described with reference to the flowcharts shown in FIGS. In this charging operation, the switch 40 is always in a connected state (closed state), and the switches 41 and 42 are switched. FIG. 4 shows a first charging process performed while the switches 41 and 42 are connected, and FIG. 5 shows a second charging process performed after the switches 41 and 42 are disconnected.

  In the first charging process of FIG. 4, the HCU 10 determines whether the engine 2 is operating and the switch 41 is connected (step S1).

  If it is determined in step S1 that the engine 2 is not operating or the switch 41 is not connected, the HCU 10 starts the engine 2 (step S6) and connects the switch 41 (step S7). Proceed to S2.

  When it is determined in step S1 that the engine 2 is operating and the switch 41 is connected, the HCU 10 increases the power generation voltage of the ISG 20 to the full charge voltage of the second power storage device 31 (step S2).

  By this step S2, the full charge voltage of the second power storage device 31 is applied from the ISG 20 to the first power storage device 30 and the second power storage device 31, and the first power storage device 30 and the second power storage device 31 are charged. .

  Next, the HCU 10 determines whether or not the charging current to the second power storage device 31 has become close to 0 (step S3). This determination is continued until the state of charge of the second power storage device 31 rises to near full charge and the charge current drops to near zero.

  If it is determined in step S3 that the charging current has become close to 0, the HCU 10 stops the power generation torque of the ISG 20 and stops the power generation of the ISG 20 (step S4).

  Next, the HCU 10 disconnects the switch 41 (step S5), and ends one routine of this flowchart.

  When the switch 41 is disconnected in step S5, the ISG 20 and the second power storage device 31 are electrically disconnected, and charging of the second power storage device 31 is stopped. On the other hand, since the electrical connection between ISG 20 and first power storage device 30 is maintained, charging of first power storage device 30 is continued.

  In the second charging process of FIG. 5, the HCU 10 determines whether or not the switch 41 is disconnected (step S11).

  If it is determined in step S11 that the switch 41 is not disconnected (connected), the HCU 10 disconnects the switch 41 (step S16), and proceeds to step S12.

  When it is determined in step S11 that the switch 41 is disconnected, the HCU 10 increases the power generation voltage of the ISG 20 to the full charge voltage of the first power storage device 30 made of a lead battery (step S12). In step S <b> 12, the HCU 10 may increase the power generation voltage of the ISG 20 to the upper limit voltage that can be applied to the first power storage device 30.

  By this step S12, the full charge voltage is applied from the ISG 20 to the first power storage device 30, and the charging of the first power storage device 30 is continued.

  Next, the HCU 10 determines whether or not the charging current to the first power storage device 30 has become close to 0 (step S13). This determination is continued until the state of charge of the first power storage device 30 rises to near full charge and the charge current drops to near zero.

  When it is determined in step S3 that the charging current has become close to 0, the HCU 10 stops the power generation torque of the ISG 20 and stops the power generation of the ISG 20 (step S14).

  Next, the HCU 10 stops the engine 2 (step S15) and ends one routine of this flowchart.

  FIG. 6 shows a timing chart when the first charging process of FIG. 4 and the second charging process of FIG. 5 are executed.

  In FIG. 6, a period from the initial state to time t1 represents a state when the first charging process of FIG. 4 is performed. Moreover, the period from the time t1 to the time t2 represents the state when the 2nd charge process of FIG. 5 is implemented.

  Prior to time t1, the engine 2 is operating and power generation by the ISG 20 is possible. Prior to time t1, a switch 41 as a changeover switch is connected.

  In a state where the switch 41 is connected, a first connection state is formed in which the first power storage device 30 and the second power storage device 31 are connected in parallel to the ISG 20 serving as a generator. This first connection state is a state in which both the first power storage device 30 and the second power storage device 31 can be charged from the ISG 20.

  When the power generation torque and power generation voltage of the ISG 20 rise to the full charge voltage of the second power storage device 31, the full charge voltage of the second power storage device 31 is applied to the first power storage device 30 and the second power storage device 31, The first power storage device 30 and the second power storage device 31 are charged.

  By performing this charging, the voltage of the first power storage device 30 (referred to as lead battery voltage in the drawing) and the voltage of the second power storage device 31 (Li battery voltage in the drawing) increase.

  In addition, charging is performed to generate a charging current to the first power storage device 30 (referred to as lead battery current in the drawing) and a charging current to the second power storage device 31 (Li battery current in the drawing). . The lead battery current and the Li battery current gradually decrease to near zero as charging progresses and approaches full charge.

  Thereafter, when the Li battery current of the second power storage device 31 decreases to near 0 because the second power storage device 31 is fully charged, the power generation torque and power generation voltage of the ISG 20 are decreased to zero. That is, the ISG 20 temporarily stops power generation. In this state, the lead battery voltage of the first power storage device 30 and the Li battery voltage of the second power storage device 31 have reached the full charge voltage of the second power storage device 31.

  Thereafter, the switch 41 is disconnected at time t1. When switch S41 is disconnected, a second connection state is formed in which first power storage device 30 is connected to ISG 20 serving as the generator. This second connection state is a state in which the second power storage device 31 is disconnected from the ISG 20 and only the first power storage device 30 can be charged from the ISG 20.

  When the power generation torque and power generation voltage of ISG 20 rise to the full charge voltage of first power storage device 30, this full charge voltage is applied to first power storage device 30, and first power storage device 30 is charged.

  Thereafter, when the lead battery current of the first power storage device 30 decreases to near 0 because the first power storage device 30 is fully charged, the power generation torque and power generation voltage of the ISG 20 are decreased to zero. Thereafter, the engine 2 is stopped at time t2.

  Here, the voltage applied to first power storage device 30 during the period from time t1 to time t2 can be charged to first power storage device 30 instead of the full charge voltage of first power storage device 30, as shown in FIG. An upper limit voltage may be used.

  In FIG. 7, a case where the first power storage device 30 is charged by applying a full charge voltage (same as in FIG. 6) is referred to as a normal mode, and a chargeable upper limit voltage is applied and applied to the first power storage device 30. The case is described as a time reduction mode.

  In the time reduction mode, the power generation torque and power generation voltage of the ISG 20 rise to the upper limit voltage that can charge the first power storage device 30 during the period from time t1 to time t2. Then, the upper limit voltage is applied to the first power storage device 30 and the first power storage device 30 is charged.

  Thereby, the time until the first power storage device 30 is fully charged is shortened.

  Thereafter, when the lead battery current of the first power storage device 30 decreases to near 0 because the first power storage device 30 is fully charged, the power generation torque and power generation voltage of the ISG 20 are decreased to zero. Thereafter, the engine 2 is stopped at time t2.

  The effects of the hybrid vehicle according to the present embodiment described above will be described.

  The hybrid vehicle 1 according to the present embodiment includes the ISG 20 that generates power using engine power, the first power storage device 30 and the second power storage device 31 having different characteristics, and the charge states of the first power storage device 30 and the second power storage device 31. A first charge state detection unit 61 and a second charge state detection unit 62 that detect each of them are provided.

  Hybrid vehicle 1 has a first connection state in which first power storage device 30 and second power storage device 31 are connected in parallel to ISG 20, and second connection in which first power storage device 30 is connected to ISG 20. The switches 40, 41, 42 for forming any one of the states are provided.

  The hybrid vehicle 1 also includes a power generation control unit 10A that controls the power generation state of the ISG 20 and the connection states of the switches 40, 41, and 42.

  When power generation control unit 10A determines that charging of first power storage device 30 or second power storage device 31 is necessary based on the charging state detected by first charging state detection unit 61 and second charging state detection unit 62 The switches 40, 41, 42 are set to the first connection state, and then the ISG 20 is caused to start power generation.

  Thereafter, when the second power storage device 31 is fully charged, the power generation control unit 10A causes the ISG 20 to continue power generation after setting the switches 40, 41, and 42 to the second connection state.

  With this configuration, the first power storage device 30 and the second power storage device 31 having different characteristics can be charged simultaneously by setting the switches 40, 41, and 42 to the first connection state. In addition, when the second power storage device 31 is fully charged, the second power storage device 31 can be disconnected from the ISG 20 by setting the switches 40, 41, 42 to the second connection state, and charging the first power storage device 30. Can continue until fully charged.

  Therefore, it is possible to charge the first power storage device 30 and the second power storage device 31 until they are fully charged while preventing overcharging of the second power storage device 31. As a result, the staying time in the EV traveling mode can be extended and the fuel consumption can be improved.

  Further, in the hybrid vehicle 1 of the present embodiment, the power generation control unit 10 </ b> A sets the power generation voltage of the ISG 20 to the upper limit voltage that allows the first power storage device 30 to be charged when continuing to charge the first power storage device 30. It has become.

  With this configuration, the first power storage device 30 is charged with the upper limit voltage at which the first power storage device 30 can be charged, so that the charging of the first power storage device 30 can be completed early.

  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.

DESCRIPTION OF SYMBOLS 1 Hybrid vehicle 2 Engine 4 Motor generator 10A Power generation control part 20 ISG (generator)
30 1st electrical storage apparatus (1st battery)
31 Second power storage device (second battery)
40, 41, 42 switch (connection switch)
61 1st charge condition detection part (charge condition detection part)
62 2nd charge condition detection part (charge condition detection part)

Claims (2)

A hybrid vehicle that includes an engine and a motor generator as drive sources, and that travels by power output from at least one of the engine and the motor generator,
A generator for generating electric power by the engine;
A first battery and a second battery having different characteristics;
A charge state detection unit for detecting a charge state of each of the first battery and the second battery;
One of a first connection state in which the first battery and the second battery are connected in parallel to the generator and a second connection state in which the first battery is connected to the generator Forming a connection switch;
A power generation control unit for controlling the power generation state of the generator and the connection state of the connection switch,
The power generation control unit
When it is determined that the first battery or the second battery needs to be charged based on the charge state detected by the charge state detection unit, the generator is started to generate power after the connection switch is set to the first connection state. Let
The hybrid vehicle control device according to claim 1, wherein when the second battery is fully charged, the power generation is continued by the generator after the connection switch is set to the second connection state.   2. The hybrid according to claim 1, wherein the power generation control unit sets the power generation voltage of the generator to an upper limit voltage that can charge the first battery when continuing to charge the first battery. Vehicle control device.