Hybrid vehicle control device

Abstract

To provide a control device for a hybrid vehicle, capable of suppressing a reduction in travelable distance if there occurs a predetermined abnormality in which an internal combustion engine cannot be started by using an electric motor and an engagement device.SOLUTION: A hybrid vehicle 10 includes an engine 12 and an electric motor MG as a driving force source for traveling, a clutch K0 for connecting / disconnecting power transmission between the engine 12 and the electric motor MG, and a starter motor 70 for starting the engine 12. When receiving a start request for a driving force source PG for traveling, an electronic control device 100 for the hybrid vehicle 10 uses the starter motor 70 to start the engine 12 if there is detected, before the start request, a predetermined abnormality in which the engine 12 cannot be started by using the electric motor MG and the clutch K0.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a control device for a hybrid vehicle that includes an internal combustion engine and an electric motor as driving power sources for traveling, an engagement device that connects and disconnects power transmission between the internal combustion engine and the electric motor, and a starter motor that starts the internal combustion engine. [Background technology]

[0002] There is known a control device for a hybrid vehicle that includes an internal combustion engine and an electric motor as driving power sources for running, an engagement device that connects and disconnects the power transmission between the internal combustion engine and the electric motor, and a starter motor that starts the internal combustion engine, and a method for starting the internal combustion engine by cranking the internal combustion engine using the electric motor and the engagement device. For example, the method described in Patent Document 1 is one such method. The method described in Patent Document 1 also describes starting the internal combustion engine using the starter motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-159680 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the hybrid vehicle described in Patent Document 1, when a start request for the driving force source for driving is received, the vehicle may be put into a state in which the vehicle can travel in a travel mode in which the driving force for driving is output only from the electric motor. In this case, if a certain abnormality occurs that makes it impossible to start the internal combustion engine using the electric motor and the engagement device, the internal combustion engine cannot be started using the electric motor and the engagement device while traveling in the travel mode in which the driving force for driving is output only from the electric motor. Therefore, the vehicle can only travel with the amount of charge actually stored in the battery that supplies power to the electric motor, and there is a risk that the travelable distance will be significantly reduced.

[0005] The present invention has been made against the background of the above circumstances, and its purpose is to provide a control device for a hybrid vehicle that can suppress a decrease in driving distance when a specific abnormality occurs that makes it impossible to start the internal combustion engine using the electric motor and engagement device. [Means for solving the problem]

[0006] The gist of the first invention is as follows: (a) A hybrid vehicle including an internal combustion engine and an electric motor as driving power sources for traveling, an engagement device that connects and disconnects power transmission between the internal combustion engine and the electric motor, and a starter motor that starts the internal combustion engine. A hybrid vehicle in which the driving mode is switched to any one of a BEV driving mode, an engine driving mode, and an HEV driving mode based on the vehicle state from a predetermined driving force source switching map. A control device, (b) A request to start the driving power source for traveling is received (c) a start-up request determination unit that determines whether or not the start-up request has been received; In this case, if a predetermined abnormality that makes it impossible to start the internal combustion engine using the electric motor and the engagement device is detected before the start request, Regardless of the vehicle condition, Starting the internal combustion engine using the starter motor and (d) a hybrid control unit that, when the start-up method determination unit determines that the internal combustion engine is to be started using the starter motor, starts the internal combustion engine using the starter motor. The point is... Effect of the Invention

[0007] According to the hybrid vehicle control device of the first invention, The start method determination unit: When a start request for the driving power source for traveling is received, if a predetermined abnormality that makes it impossible to start the internal combustion engine using the electric motor and the engagement device is detected before the start request, Regardless of the vehicle condition, The starter motor is used to start the internal combustion engine. of Start It was decided Will be and a hybrid control unit starts the internal combustion engine using a starter motor. In this way, if a predetermined abnormality that makes it impossible to start the internal combustion engine using the electric motor and the engagement device is detected before a start request is made, the internal combustion engine is started using the starter motor. Since the hybrid vehicle is driven by the driving force for driving output from the started internal combustion engine, the drivable distance is not limited to the amount of charge actually stored in the battery that supplies power to the electric motor, and therefore a decrease in the drivable distance is suppressed.

[0008] According to the control device for a hybrid vehicle of the second invention, in the first invention, (a) when the predetermined abnormality is detected, the detection of the predetermined abnormality is stored, and (b) when the start request is received and the detection of the predetermined abnormality is stored, the internal combustion engine is started using the starter motor. For example, the time required to detect the predetermined abnormality may be longer than the time required to start the driving power source for driving in response to the start request. Even in such a case, since the detection of the predetermined abnormality is stored in advance, the start control of the internal combustion engine can be executed more quickly using the starter motor when the start request for the driving power source for driving is received, compared to when the detection of the predetermined abnormality is not stored in advance. This suppresses deterioration of drivability. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic configuration diagram of a hybrid vehicle equipped with an electronic control device according to an embodiment of the present invention, and is also a functional block diagram showing essential parts of control functions for various controls in the hybrid vehicle. [Diagram 2] 2 is an example of a flowchart illustrating a control operation of the electronic control device shown in FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of the various parts are not necessarily drawn accurately. EXAMPLES

[0011] FIG. 1 is a schematic configuration diagram of a hybrid vehicle 10 (hereinafter simply referred to as “vehicle 10”) equipped with an electronic control device 100 according to an embodiment of the present invention, and is also a functional block diagram showing the main control functions for various controls in vehicle 10.

[0012] The vehicle 10 includes an engine 12 and an electric motor MG, which are driving power sources PG for traveling, and a power transmission device 16 provided on a power transmission path PT between the engine 12 and driving wheels 14. The vehicle 10 is a hybrid vehicle. The vehicle 10 also includes an inverter 52, a hydraulic control circuit 54, an EOP 56, which is an electric oil pump, a main battery 60, a system main relay 62, an auxiliary battery 66, a DC / DC converter 68, a starter motor 70, and an electronic control device 100.

[0013] The engine 12 is a well-known internal combustion engine. An electronic control device 100 (described later) controls an engine control device 50 including a throttle actuator, a fuel injection device, an ignition device, and the like provided on the vehicle 10, thereby controlling the engine torque Te [Nm] outputted from the engine 12. In this specification, the terms torque, driving force, power, and force (power) are synonymous unless otherwise specified. The engine 12 corresponds to the "internal combustion engine" in the present invention.

[0014] The power transmission device 16 includes, in order from the engine 12 side, an engine connecting shaft 20, a clutch K0, an electric motor connecting shaft 22, a torque converter 24, an AT input shaft 26 which is an input rotating member of the automatic transmission 28, and the automatic transmission 28, inside a case 18 which is a non-rotating member attached to the vehicle body. The power transmission device 16 also includes a differential gear 32 which is connected to an AT output shaft 30 which is an output rotating member of the automatic transmission 28, a pair of drive shafts 34 which are connected to the differential gear 32, and the like.

[0015] The engine connecting shaft 20 is a member that connects the engine 12 and the clutch K0, and is, for example, a crankshaft. A flywheel 12a is attached to the engine connecting shaft 20 so as to be unable to rotate relative to the engine 12.

[0016] The electric motor MG is a so-called motor generator that has a function as an electric motor that generates mechanical power from electric energy (electric motor function) and a function as a generator that generates electric energy from mechanical power (generator function). The electric motor MG corresponds to the "electric motor" in the present invention.

[0017] A clutch K0 is provided between an engine connecting shaft 20 connected to the engine 12 and an electric motor connecting shaft 22 connected to a rotor of the electric motor MG. The clutch K0 is an engagement device capable of connecting and disconnecting the power transmission between the engine 12 and the electric motor connecting shaft 22, and is, for example, a wet-type multi-plate hydraulic friction engagement device. When the clutch K0 is in an engaged state, the clutch K0 enables the power transmission between the engine 12 and the electric motor MG. When the clutch K0 is in a released state, the clutch K0 cuts off the power transmission between the engine 12 and the electric motor MG. When the clutch K0 is in a half-engaged state, i.e., a slipping engagement state, the clutch K0 enables the power transmission between the engine 12 and the electric motor MG according to a transmission torque capacity (the engagement force of the clutch K0) based on the slipping engagement state. The clutch K0 corresponds to the "engagement device" in the present invention.

[0018] The electric motor MG is driven to rotate by the electric power stored in the main battery 60, and outputs the driving force for running the hybrid vehicle 10. The electric motor MG also generates electric power from the driving force for running input from the engine 12 via the clutch K0, and generates electric power by converting the driven force input from the drive wheels 14 side into electric power by regeneration. The generated electric power is charged to the main battery 60 via the inverter 52 and the system main relay 62.

[0019] The inverter 52 is a power supply circuit provided between the electric motor MG and the main battery 60, and converts direct current to alternating current or alternating current to direct current under the control of the electronic control device 100. For example, the inverter 52 converts direct current supplied from the main battery 60 to alternating current and outputs the alternating current to the electric motor MG to drive it, or converts alternating current generated by the electric motor MG to direct current and outputs the direct current to the main battery 60.

[0020] The starter motor 70 is a motor that starts the engine 12 and is a well-known motor that can crank the engine 12 by meshing with a ring gear engraved on the outer periphery of the flywheel 12a, for example.

[0021] The main battery 60 is a chargeable and dischargeable secondary battery, such as a lithium ion battery or a nickel metal hydride battery. The main battery 60 is a first battery used mainly to supply power for driving the electric motor MG and to charge the electric power generated by the electric motor MG through regeneration. The auxiliary battery 66 is a chargeable and dischargeable secondary battery, such as a lead storage battery or a lithium ion battery. The auxiliary battery 66 is a second battery used mainly to supply power to the auxiliary devices (such as the starter motor 70 and the engine control device 50). Due to the difference in use, the main battery 60 has a higher battery voltage Vbat than the auxiliary battery 66. For example, the auxiliary battery 66 has a voltage of 12 [V], whereas the main battery 60 has a higher voltage.

[0022] The main battery 60 is connected to the inverter 52 via a system main relay 62. The system main relay 62 is, for example, a mechanical relay that is switched between an open state (disconnected state) and a closed state (connected state) by the electronic control device 100. When the system main relay 62 is in the closed state, power can be exchanged between the main battery 60 and the inverter 52. When the system main relay 62 is in the open state, power cannot be exchanged between the main battery 60 and the inverter 52.

[0023] The DC / DC converter 68 is a power supply circuit that is provided between the power line 64 that connects the inverter 52 and the system main relay 62 and the auxiliary battery 66, and that boosts and lowers the voltage of a direct current. For example, the DC / DC converter 68 lowers the voltage supplied from the main battery 60 to the power line 64 to charge the auxiliary battery 66 with a direct current having a lower voltage than the main battery 60, or boosts the direct current supplied from the auxiliary battery 66 to output a direct current having a higher voltage than the auxiliary battery 66 to the power line 64.

[0024] The torque converter 24 is a well-known torque converter. The torque converter 24 includes a pump wheel connected to the electric motor connecting shaft 22, a turbine wheel connected to the AT input shaft 26, and a lock-up clutch 40 that directly connects the pump wheel and the turbine wheel. The torque converter 24 is a fluid-type power transmission device that can transmit the driving force for traveling output from the driving force source PG (engine 12, electric motor MG) from the electric motor connecting shaft 22 to the AT input shaft 26 via a fluid. The vehicle 10 includes a MOP 42 that is a mechanical oil pump. The MOP 42 is connected to the pump wheel, and is rotationally driven by the driving force source PG (engine 12, electric motor MG) to discharge hydraulic oil OIL used in the power transmission device 16.

[0025] The EOP 56 is a known oil pump that can be driven by the rotation of an EOP drive motor 58, independently of the rotation of the engine 12 and the electric motor MG, which are the driving power source PG for traveling. The EOP drive motor 58 is a known electric motor, and the rotation speed of the EOP drive motor 58 is controlled by an inverter (not shown) being controlled by the electronic control device 100. The EOP 56 is rotationally driven by the EOP drive motor 58 to discharge hydraulic oil OIL used in the power transmission device 16.

[0026] The automatic transmission 28 is a known automatic transmission that changes the speed of the driving force input from the driving force source PG (engine 12, electric motor MG) to the AT input shaft 26 and outputs the changed speed to the AT output shaft 30, and is, for example, a stepped transmission of a planetary gear type or a constant meshing parallel shaft type, or a continuously variable transmission of a belt type or a power roller type. The automatic transmission 28 is controlled by a hydraulic control circuit 54 controlled by the electronic control device 100 so that a desired gear ratio γat is formed from among different gear ratios γat. In this embodiment, the automatic transmission 28 is a known planetary gear type automatic transmission that includes a plurality of planetary gear sets and a plurality of gear shift engagement devices CB. The gear shift engagement devices CB are switched between engagement and disengagement states such as a fully engaged state, a half-engaged state, and a released state by adjusting the hydraulic pressure supplied from the hydraulic control circuit 54 to a hydraulic actuator that controls the engagement and disengagement state of the gear shift engagement devices CB. In the automatic transmission 28, one of a plurality of gear stages (also called gear ratios) with different speed ratios (also called gear ratios) γat (=AT input rotation speed Ni [rpm] / AT output rotation speed No [rpm]) is formed by engaging one of the engagement devices for shifting gears CB.

[0027] The differential gear 32 is a well-known differential gear that receives the driving force for traveling transmitted from the AT output shaft 30 of the automatic transmission 28 and transmits equal driving torque to a pair of drive shafts 34 while allowing an appropriate difference in rotational speed.

[0028] The hydraulic control circuit 54 uses the hydraulic pressure of the hydraulic oil OIL discharged from the MOP 42 and the EOP 56 as the source pressure, and supplies the necessary hydraulic oil OIL to each part in the case 18. For example, the hydraulic control circuit 54 generates hydraulic pressure for controlling the engagement and disengagement of the clutch K0, hydraulic pressure for controlling the shifting of the automatic transmission 28, and hydraulic pressure for controlling the engagement and disengagement of the lock-up clutch 40 of the torque converter 24, and supplies these to each hydraulic actuator in the case 18.

[0029] In the power transmission device 16, when the clutch K0 is engaged, the driving force for traveling output from the engine 12 is transmitted from the engine connecting shaft 20 through the clutch K0, the electric motor connecting shaft 22, the torque converter 24, the automatic transmission 28, the differential gear 32, the drive shaft 34, etc. in this order to the driving wheels 14. The driving force for traveling output from the electric motor MG is transmitted from the electric motor connecting shaft 22 through the torque converter 24, the automatic transmission 28, the differential gear 32, the drive shaft 34, etc. in this order to the driving wheels 14, regardless of whether the clutch K0 is engaged or disengaged.

[0030] The vehicle power switch 94 is disposed, for example, near the driver's seat, and is an automatic reset push button switch that is operated to switch the power supply state of the vehicle 10.

[0031] For example, pressing the vehicle power switch 94 accompanied by depressing the brake pedal (not shown) switches the power supply state of the vehicle 10 to an activated state that enables the vehicle to run. When the vehicle power switch 94 is switched to the activated state, a power switch signal SWon is output and the electric motor MG or the engine 12 is placed in a state in which it is possible to output driving force for running, i.e., the power switch signal SWon is placed in an ON state and the vehicle is placed in a state in which it is possible to run. In this embodiment, a request to start the driving force source PG for running is a pressing operation of the vehicle power switch 94 to switch to the activated state. The start request is a request to switch the state of the vehicle 10 to a state in which it is possible to run.

[0032] For example, by pressing the vehicle power switch 94 without depressing the brake pedal (not shown), the power supply state of the vehicle 10 is switched sequentially between a power-on state (IG-ON state) for enabling the vehicle to travel, a partial power-on state (ACC-ON state, IG-OFF state) for turning off the power related to the vehicle travel and turning on the power not related to the vehicle travel to enable some functions of the vehicle 10, such as an audio device, a car navigation device, etc. (not shown), and a vehicle power-off state (ALL-OFF state) in which all power sources are turned off. When the vehicle 10 is stopped, pressing the vehicle power switch 94 to turn the vehicle power off state stops the driving power source PG for traveling, i.e., the vehicle is no longer in a state in which it is possible to travel.

[0033] In the vehicle 10, any one of the driving modes of the BEV driving mode, the engine driving mode, and the HEV driving mode can be selected. The BEV driving mode is a driving mode in which the engine 12 is stopped and the motor MG is powered to perform BEV (Battery Electric Vehicle) driving using only the motor MG as a driving force source among the driving force sources PG. The engine driving mode is a driving mode in which the clutch K0 is engaged and only the engine 12 as a driving force source among the driving force sources PG. The HEV driving mode is a driving mode in which the clutch K0 is engaged and HEV (Hybrid Electric Vehicle) driving using both the engine 12 and the motor MG as driving force sources among the driving force sources PG.

[0034] The driving mode of the vehicle 10 is switched among the BEV driving mode, the engine driving mode, and the HEV driving mode, for example, by a driving force source switching map. The driving force source switching map is a relationship in which the driving modes are predetermined in two-dimensional coordinates with, for example, the vehicle speed V [km / h] and the required driving torque Trdem [Nm] as variables. In general, the BEV driving mode is selected in a low vehicle speed region where the vehicle speed V is relatively low and the required driving torque Trdem is relatively low (= the accelerator opening θacc is relatively low) where the engine efficiency is reduced. On the other hand, the engine driving mode or the HEV driving mode is selected in a high vehicle speed region where the vehicle speed V is relatively high or the required driving torque Trdem is relatively high (= the accelerator opening θacc is relatively high). The BEV driving mode is applied when the state of charge value (the ratio of the amount of charge actually stored to a predetermined full charge capacity) SOC [%] of the main battery 60 is equal to or higher than a predetermined engine start threshold. In other words, when the state of charge value SOC of the main battery 60 is less than the engine start threshold, there is no region in the driving force source switching map where the BEV driving mode is selected, and all regions are set to be regions where the engine driving mode or the HEV driving mode is selected. The engine start threshold is a predetermined threshold for determining that the state of charge value SOC is at a value at which the engine 12 needs to be forcibly started to charge the main battery 60.

[0035] The electronic control device 100 includes a so-called microcomputer equipped with, for example, a CPU, RAM, ROM, an input / output interface, etc., and the CPU executes various controls of the vehicle 10 by performing signal processing according to a program previously stored in the ROM while utilizing the temporary storage function of the RAM. The electronic control device 100 includes computers for engine control, electric motor control, hydraulic control, etc. as necessary. The electronic control device 100 corresponds to the "control device" in the present invention.

[0036] The electronic control device 100 receives various signals based on detection values ​​from various sensors provided in the vehicle 10 (for example, an engine rotation speed sensor 80, a turbine rotation speed sensor 82, an output rotation speed sensor 84, an electric motor rotation speed sensor 86, an accelerator opening sensor 88, a throttle valve opening sensor 90, a battery sensor 92, a vehicle power switch 94, etc.) (for example, an engine rotation speed Ne [rpm] which is the rotation speed of the engine 12, a turbine rotation speed Nt [rpm] which is the same value as the AT input rotation speed Ni [rpm], an AT output rotation speed corresponding to the vehicle speed V, a vehicle speed V ... The input signals include the speed No [rpm], the motor rotation speed Nmg [rpm] which is the rotation speed of the electric motor MG, the accelerator opening θacc [%] which is the amount of accelerator operation by the driver which indicates the magnitude of the driver's acceleration operation, the throttle valve opening θth [%] which is the opening of the electronic throttle valve, the battery temperature THbat [°C] of the main battery 60, the battery charge / discharge current Ibat [A] and the battery voltage Vbat [V], and the power switch signal SWon which is output when the vehicle power switch 94 is switched to the start-up state by the driver.

[0037] The electronic control device 100 outputs various command signals (e.g., an engine control signal Se for controlling the engine 12, an electric motor control signal Smg for controlling the electric motor MG, a shift control signal Sat for controlling the shift engagement device CB, a K0 control signal Sk0 for controlling the clutch K0, an LU control signal Slu for controlling the lock-up clutch 40, an EOP control signal Seop for controlling the EOP 56, a relay control signal Ssmr for controlling the opening and closing of the system main relay 62, a converter control signal Scon for controlling the voltage conversion of the DC / DC converter 68, etc.) to each device provided in the vehicle 10 (e.g., the engine control device 50, the inverter 52, the hydraulic control circuit 54, the EOP drive motor 58, the system main relay 62, the DC / DC converter 68, etc.).

[0038] The electronic control unit 100 functionally comprises a hybrid control unit 102 , a start control unit 104 , a clutch control unit 106 , a gear shift control unit 108 , and an abnormality detection unit 110 .

[0039] The hybrid control unit 102 functionally comprises an engine control unit 102a that controls the operation of the engine 12, and an electric motor control unit 102b that controls the operation of the electric motor MG via the inverter 52, and executes hybrid drive control using the engine 12 and the electric motor MG, etc., using these control functions.

[0040] The hybrid control unit 102 calculates the drive demand amount of the vehicle 10 by the driver, for example, by applying the actual accelerator opening θacc and vehicle speed V to a drive demand amount map. The drive demand amount map is a map in which the relationship between the accelerator opening θacc, the vehicle speed V, and the drive demand amount is determined in advance experimentally or by design and stored. The drive demand amount is, for example, the required drive torque Trdem at the drive wheels 14. In other words, the required drive torque Trdem is the required drive power Prdem [W] at the vehicle speed V at that time. The drive demand amount can also be the required drive force Frdem [N] at the drive wheels 14, the required output torque at the AT output shaft 30, or the like. In calculating the drive demand amount, the AT output rotation speed No, or the like, can be used instead of the vehicle speed V.

[0041] The hybrid control unit 102 outputs an engine control signal Se for controlling the engine 12 and an electric motor control signal Smg for controlling the electric motor MG so as to realize the required driving power Prdem, taking into consideration the transmission loss, the auxiliary load, the gear ratio γat of the automatic transmission 28, the chargeable electric power Win [W] and the dischargeable electric power Wout [W] of the main battery 60, etc. The engine control signal Se is, for example, a command value for the engine power Pe [W], which is the power of the engine 12 that outputs the engine torque Te at the engine rotation speed Ne at that time. The electric motor control signal Smg is, for example, a command value for the power consumption Wm [W] of the electric motor MG that outputs the electric motor torque Tmg [Nm] at the electric motor rotation speed Nmg at that time.

[0042] The chargeable power Win of the main battery 60 is the maximum power that can be input, which specifies the limit on the input power of the main battery 60, and indicates the input limit of the main battery 60. The dischargeable power Wout of the main battery 60 is the maximum power that can be output, which specifies the limit on the output power of the main battery 60, and indicates the output limit of the main battery 60. The chargeable power Win and dischargeable power Wout of the main battery 60 are calculated by the electronic control device 100 based on, for example, the battery temperature THbat and the state of charge value SOC of the main battery 60.

[0043] The hybrid control unit 102 controls the vehicle 10 in a driving mode (BEV driving mode, engine driving mode, HEV driving mode) according to the state of the vehicle 10. For example, the driving mode according to the state of the vehicle 10 is selected by the driving power source switching map described above.

[0044] The engine control unit 102a controls the engine torque Te so as to realize the drive demand amount for the vehicle 10. The motor control unit 102b controls the motor torque Tmg so as to realize the drive demand amount for the vehicle 10. Specifically, in the BEV driving mode, the motor control unit 102b controls the motor torque Tmg so as to realize the required drive torque Trdem. In the engine driving mode, the engine control unit 102a controls the engine torque Te so as to realize the entire required drive torque Trdem, and the motor control unit 102b controls the motor torque Tmg so as to generate power with the surplus of the engine torque Te when there is a surplus of the engine torque Te with respect to the required drive torque Trdem. In the HEV driving mode, the engine control unit 102a controls the engine torque Te so as to realize a part of the required drive torque Trdem, and the motor control unit 102b controls the motor torque Tmg so as to compensate for the torque that is insufficient in the engine torque Te with respect to the required drive torque Trdem.

[0045] The shift control unit 108 judges whether to shift the automatic transmission 28 by using, for example, a shift map, and outputs a shift control signal Sat for executing shift control as necessary to the hydraulic control circuit 54. The shift map is a predetermined relationship having a shift line for judging whether to shift the automatic transmission 28 on a two-dimensional coordinate system having, for example, vehicle speed V and required driving torque Trdem as variables. In the shift map, the AT output rotation speed No may be used instead of the vehicle speed V, and the required driving force Frdem, accelerator opening θacc, throttle valve opening θth, etc. may be used instead of the required driving torque Trdem.

[0046] Next, a case will be described where, while the driving power source PG is stopped, the driver operates the vehicle power switch 94 to request activation of the driving power source PG.

[0047] The activation control unit 104 functionally comprises an activation request determination unit 104a, an abnormality determination unit 104b, and an activation method determination unit 104c.

[0048] The start-up request determination unit 104a determines whether or not a start-up request for the driving power source PG for driving is received. For example, the start-up request determination unit 104a determines whether or not a start-up request for the driving power source PG for driving is received based on whether or not the power switch signal SWon is in the on state. Specifically, when the driver presses the vehicle power switch 94 to switch it to the activated state, it is determined that a start-up request for the driving power source PG for driving is received.

[0049] When the start request determination unit 104a determines that a start request for the driving power source PG for driving is received, the abnormality determination unit 104b determines whether or not a predetermined abnormality that makes it impossible to start the engine 12 using the electric motor MG and the clutch K0 has been detected before the start request for the driving power source PG for driving. For example, whether or not a predetermined abnormality has been detected is determined based on whether or not the detection of the predetermined abnormality is stored by the abnormality detection unit 110 described later. The predetermined abnormality is an abnormality that makes it impossible to crank and start the engine 12 using the electric motor MG and the clutch K0, for example, (a) when the system main relay 62 is broken, (b) when the electric motor rotation speed sensor 86 is a resolver and the rotation angle learning of the resolver is not completed, or (c) when a communication abnormality (disruption of communication) occurs between the engine control unit 102a and the clutch control unit 106. The rotation angle learning of the resolver is a learning that corrects the difference between the rotation position of the electric motor MG detected by the resolver and the actual rotation position of the electric motor MG so that it falls within a predetermined allowable range.

[0050] (a) When the system main relay 62 is broken (for example, when the electrical resistance in the closed state of the system main relay 62 is high), the connection state between the main battery 60 and the inverter 52 is not normal, so it is not preferable to crank the engine 12 using the electric motor MG and the clutch K0. (b) When the rotation angle learning of the resolver is not completed, for example, when the electric motor MG is driven and controlled by a rectangular wave drive that drives with a rectangular wave, there is a possibility that an unintended driving force for running is output from the electric motor MG due to a phase shift. Therefore, the drive control of the electric motor MG by the rectangular wave drive is prohibited, and in the state in which this rectangular wave drive is prohibited, there is a possibility that the cranking torque Tcr cannot be output from the electric motor MG. (c) When a communication abnormality (disruption of communication) occurs between the engine control unit 102a and the clutch control unit 106, the engine control unit 102a cannot supply fuel to the engine 12 or ignite the engine 12 in conjunction with the cranking of the engine 12 by the clutch K0 and the electric motor MG, as described later.

[0051] When the start request determination unit 104a determines that a start request for the driving power source PG for driving is received and the abnormality determination unit 104b determines that a predetermined abnormality was detected before the start request for the driving power source PG for driving, the start method determination unit 104c determines to select a start method that enables the vehicle 10 to run in the engine running mode regardless of the state of the vehicle 10. For example, even if the vehicle speed V and the accelerator opening θacc are both zero immediately after receiving the start request for the driving power source PG and are in the BEV running mode range in the driving power source switching map, the vehicle 10 is enabled to run in the engine running mode. Then, the start method determination unit 104c determines to use the starter motor 70 to crank the engine 12 and execute start control of the engine 12 (hereinafter referred to as "engine start control").

[0052] When the start method determination unit 104c determines to execute engine start control using the starter motor 70, the engine control unit 102a and the clutch control unit 106 of the hybrid control unit 102 execute the engine start control. Specifically, the engine control unit 102a causes the starter motor 70 to crank the engine 12 via the flywheel 12a, and also starts fuel supply to the engine 12, ignition, and the like. After the engine 12 has completely exploded (started operation) and is capable of self-operation, the clutch control unit 106 switches the clutch K0 from a released state to a half-engaged state, and then to an engaged state. This allows the driving force for running output from the engine 12 to be transmitted to the drive wheels 14 via the clutch K0. After the engine start control is completed, the hybrid control unit 102 causes the vehicle 10 to run in the engine running mode.

[0053] When the start request determination unit 104a determines that a start request for the driving power source PG for driving is received and the abnormality determination unit 104b determines that a predetermined abnormality has not been detected before the start request for the driving power source PG for driving, the start method determination unit 104c determines the start method according to the state of the vehicle 10. For example, immediately after receiving the start request for the driving power source PG for driving, if the vehicle speed V and the accelerator opening θacc are both zero and are in the BEV driving mode area in the driving power source switching map described above, the engine start control is not executed and the vehicle is allowed to run in the BEV driving mode. After starting to run, the hybrid control unit 102 runs the vehicle 10 in either the BEV driving mode, the engine driving mode, or the HEV driving mode according to the state of the vehicle 10. The hybrid control unit 102 and the clutch control unit 106 execute the engine start control by cranking the engine 12 using the electric motor MG and the clutch K0 as necessary. Specifically, the electric motor control unit 102b controls the electric motor MG to output the cranking torque Tcr until cranking is completed in accordance with the switching of the clutch K0 from the released state to the engaged state by the clutch control unit 106. In addition, the engine control unit 102a controls the fuel supply to the engine 12, ignition, etc. in conjunction with the cranking of the engine 12 by the clutch K0 and the electric motor MG.

[0054] The abnormality detection unit 110 detects whether or not a predetermined abnormality occurs in the vehicle 10 that makes it impossible to start the engine 12 using the electric motor MG and the clutch K0. When the abnormality detection unit 110 detects the predetermined abnormality, the abnormality detection unit 110 stores the fact that the predetermined abnormality has been detected. For example, when the predetermined abnormality is not detected, the abnormality detection unit 110 turns off an abnormality detection flag, and when the predetermined abnormality is detected, the abnormality detection unit 110 turns on the abnormality detection flag.

[0055] Fig. 2 is an example of a flowchart illustrating the control operation of the electronic control device 100 shown in Fig. 1. The flowchart in Fig. 2 is repeatedly executed when the driving power source PG for traveling is stopped.

[0056] First, in step S10 (hereinafter, step will be omitted) corresponding to the function of the start request determination unit 104a, it is determined whether or not a start request for the driving power source PG has been made by the driver pressing the vehicle power switch 94. If the determination in S10 is positive, then in S20 corresponding to the function of the abnormality determination unit 104b, it is determined whether or not a predetermined abnormality that makes it impossible to start the engine 12 using the electric motor MG and the clutch K0 has been detected before the start request for the driving power source PG in S10. For example, it is determined whether or not the abnormality detection flag is on. If the determination in S10 is negative, the process ends.

[0057] If the judgment in S20 is positive, engine start control using the starter motor 70 is executed in S30, which corresponds to the functions of the start control unit 104 and the clutch control unit 106, and the vehicle 10 is caused to run in engine running mode in S40, which corresponds to the function of the hybrid control unit 102.

[0058] If the determination in S20 is negative, in S50, which corresponds to the function of the hybrid control unit 102, the vehicle 10 is caused to run in the BEV driving mode, the engine driving mode, or the HEV driving mode depending on the state of the vehicle 10. After execution of S50, in S60, which corresponds to the function of the abnormality detection unit 110, it is detected whether or not a predetermined abnormality has occurred in the vehicle 10 that makes it impossible to start the engine 12 using the electric motor MG and the clutch K0.

[0059] If the detection in S60 is positive, an abnormality detection flag is turned on in S70, which corresponds to the function of the abnormality detection unit 110. After execution of S40, if the detection in S60 is negative, or after execution of S70, the driving power source PG for traveling is stopped in S80, which corresponds to the function of the hybrid control unit 102. Then, the process ends.

[0060] According to this embodiment, when a start request for the driving power source PG for driving is received, if a predetermined abnormality that makes it impossible to start the engine 12 using the electric motor MG and the clutch K0 is detected before the start request, the engine 12 is started using the starter motor 70. In this way, if a predetermined abnormality that makes it impossible to start the engine 12 using the electric motor MG and the clutch K0 is detected before the start request, the engine 12 is started using the starter motor 70. The vehicle 10 is driven by the driving power for driving output from the started engine 12, that is, the vehicle 10 is driven in the engine driving mode, so that the drivable distance is not limited by the charge amount actually stored in the main battery 60 that supplies power to the electric motor MG, and therefore a decrease in the drivable distance is suppressed.

[0061] According to this embodiment, (a) when a predetermined abnormality is detected, the abnormality detection flag is turned on to store the detection of the predetermined abnormality, and (b) when a start request for the driving power source PG for driving is received and the abnormality detection flag stores the detection of the predetermined abnormality, the engine 12 is started using the starter motor 70. For example, the time required to detect the predetermined abnormality may be longer than the time required for the start control executed in response to the start request for the driving power source PG for driving. Even in such a case, since the detection of the predetermined abnormality is stored in advance in the abnormality detection flag, the start control of the engine 12 can be executed more quickly using the starter motor 70 when a start request for the driving power source PG for driving is received, compared to a case where the detection of the predetermined abnormality is not stored in advance in the abnormality detection flag. This suppresses deterioration of drivability.

[0062] Although the embodiment of the present invention has been described in detail above with reference to the drawings, the present invention can be applied to other embodiments.

[0063] In the above embodiment, if a start request for the driving power source PG for driving is received and the detection of a predetermined abnormality is stored in the abnormality detection flag, the engine 12 is started using the starter motor 70, but the present invention is not limited to this. For example, the electronic control device 100 may repeatedly detect whether or not a predetermined abnormality has occurred at predetermined intervals, and if a start request for the driving power source PG for driving is received after detecting the occurrence of the predetermined abnormality (i.e., if the predetermined abnormality has been detected before the start request for the driving power source PG for driving), the electronic control device 100 may start the engine 12 using the starter motor 70.

[0064] In the above-described embodiment, when a specified abnormality is detected, the fact that the specified abnormality has been detected is stored by turning on the abnormality detection flag, but this is not limited to this and any form may be used as long as the fact that a specified abnormality has been detected is stored.

[0065] In the above embodiment, the torque converter 24 is used as the fluid transmission device, but the present invention is not limited to this embodiment. For example, instead of the torque converter 24, other fluid transmission devices that do not have a torque amplifying effect, such as a fluid coupling, may be used as the fluid transmission device. Also, the fluid transmission device does not necessarily have to be provided, and may be replaced with, for example, a starting clutch.

[0066] In the above-described embodiment, the main battery 60 and the system main relay 62 are directly connected, but the present invention is not limited to this embodiment. For example, a boost converter may be provided between the main battery 60 and the system main relay 62. In this embodiment, the voltage of the main battery 60 is boosted by the boost converter, and the boosted voltage is output to the inverter 52 via the system main relay 62 and the power line 64.

[0067] It should be noted that the above is merely an embodiment of the present invention, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit of the present invention. [Explanation of symbols]

[0068] 10: Hybrid vehicles 12: Engine (internal combustion engine) 70: Starter motor 100: Electronic control device (control device) K0: Clutch (engagement device) MG: Electric motor PG: Driving power source

Claims

[Claim 1] A hybrid vehicle including an internal combustion engine and an electric motor as driving force sources for driving the vehicle, an engagement device that connects and disconnects power transmission between the internal combustion engine and the electric motor, and a starter motor that starts the internal combustion engine, the hybrid vehicle control device switching the driving mode to any one of a BEV driving mode, an engine driving mode, and an HEV driving mode based on a vehicle state from a predetermined driving force source switching map, a start request determination unit that determines whether a start request for the driving power source for traveling has been received; a start method determination unit that, when receiving the start request, determines to start the internal combustion engine using the starter motor regardless of the vehicle state if a predetermined abnormality that makes it impossible to start the internal combustion engine using the electric motor and the engagement device has been detected prior to the start request; a hybrid control unit that, when the start method determination unit determines that the internal combustion engine is to be started using the starter motor, starts the internal combustion engine using the starter motor. A control device for a hybrid vehicle.

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