Hybrid vehicle

Abstract

To provide a hybrid vehicle that is still enabled to run, even if an abnormality occurs in a DCDC converter.SOLUTION: A hybrid vehicle 100 is provided with an engine 10 and a rotary electric machine part 20. The hybrid vehicle 100 includes a battery 50, a system main relay 60, a DCDC converter 70, a diagnosing part 71 that diagnoses whether the DCDC converter 70 is normal or abnormal, and a control device 90. The engine 10 comprises a starter motor 12 and an alternator 14. When the diagnosing part 71 diagnoses the DCDC converter 70 and detects that the DCDC converter 70 is abnormal at the time of startup, the control device 90 puts the system main relay 60 in a non-connected state, and makes the starter motor 12 start the engine 10 so as to make the alternator 14 generate electricity on the basis of rotary drive of the engine 10.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to hybrid vehicles. [Background technology]

[0002] Patent Document 1 discloses a power supply system for a vehicle (electric vehicle) that includes a system main relay that connects and disconnects wiring between a battery and an inverter. The power supply system also has a function for diagnosing a welding state of the system main relay.

[0003] In this vehicle, before connecting the system main relay in the start sequence, the DC-DC converter performs drive control or stop control to diagnose the welding state of the system main relay. After diagnosing the welding state of the system main relay, the vehicle starts up by connecting the system main relay and becomes ready to run. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2020-99129 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides a hybrid vehicle that can be kept in a running state even if an abnormality occurs in a DC-DC converter. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, there is provided a hybrid vehicle having an engine and a rotating electric machine unit, the hybrid vehicle including: a battery that supplies power to the rotating electric machine unit; a system main relay that switches between connection and disconnection between the rotating electric machine unit and the battery; a DC-DC converter electrically connected to the system main relay; a diagnostic unit that diagnoses whether the DC-DC converter is normal or abnormal; and a control device, wherein the engine includes a starter motor that starts the rotational drive of the engine and an alternator that generates electricity based on the rotational drive of the engine, and the control device, when the diagnostic unit diagnoses the DC-DC converter at start-up and detects an abnormality in the DC-DC converter, disconnects the system main relay, starts the engine using the starter motor, and causes the alternator to generate electricity based on the rotational drive of the engine. [Effects of the Invention]

[0007] A hybrid vehicle according to one aspect can be kept in a running state even if an abnormality occurs in the DC-DC converter. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a schematic diagram of a hybrid vehicle drive system according to an embodiment of the present invention; [Figure 2] 4 is a flowchart illustrating an example of a method for starting a hybrid vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant explanations may be omitted.

[0010] 1 is a diagram that schematically shows a traveling drive system 1 of a hybrid vehicle 100 according to an embodiment. The hybrid vehicle 100 according to an embodiment is a vehicle that travels using the traveling drive system 1 that includes an engine 10 and a rotating electric machine unit 20 as a driving source. Specifically, the traveling drive system 1 is configured as a system for a one-motor hybrid (1M-HEV) that has one rotating electric machine unit 20.

[0011] The traveling drive device 1 includes an engine 10, a rotating electrical machine unit 20, a transmission unit 30, a transfer unit 40, a battery 50, an auxiliary battery 55, a system main relay 60, a DC-DC converter 70, and an inverter 80. The hybrid vehicle 100 also includes a control device 90 that controls each component of the traveling drive device 1, which includes a hybrid ECU (Electronic Control Unit) 91 and an engine ECU 92.

[0012] The engine 10 is an internal combustion engine that has multiple cylinders and generates rotational driving force by burning fuel (gasoline) injected into each cylinder. An output shaft 11 connected to a crankshaft in the engine 10 extends to a rotating electrical machine section 20. The engine 10 is connected to an engine ECU 92, and the crankshaft and output shaft 11 are driven to rotate by the operation of spark plugs, an electronic throttle, and other components (not shown) under the control of the engine ECU 92.

[0013] The engine 10 also includes a starter motor 12 that rotates a crankshaft when the engine 10 is started, and an alternator 14 that generates electricity by receiving the rotational drive of the engine 10. For example, the starter motor 12 and the output shaft 11 of the engine 10 are connected by a gear mechanism 13. The starter motor 12 is controlled to rotate and stop based on commands from an engine ECU 92, and rotates the engine 10 via the gear mechanism 13 when the engine 10 is started. The alternator 14 is connected to the engine 10 by a pulley mechanism 15 or the like, generates electricity by using the rotational drive of the engine 10, and supplies the generated electricity to an auxiliary battery 55 that is connected to the starter motor 12.

[0014] The rotating electrical machine unit 20 is a so-called motor generator (MG), and has both a function as a motor that generates mechanical power from electric power and a function as a generator that generates electric power from mechanical power.

[0015] For example, the rotating electrical machine unit 20 includes a stator 21, a rotor 22, an electric oil pump 23, and an engine-side clutch 24. The stator 21 is provided with a coil (not shown), which is connected to an inverter 80. The rotor 22 has a permanent magnet or the like, and rotates a rotating electrical machine shaft 26 about its axis based on the supply of three-phase AC power from the inverter 80 to the coil. In other words, the inverter 80 constitutes a part of the rotating electrical machine unit 20. The electric oil pump 23 maintains oil pressure in a hydraulic circuit (not shown) for the engine-side clutch 24 and the like when the rotating electrical machine unit 20 is started or during idling stop.

[0016] The engine-side clutch 24 switches between engagement and disengagement between the output shaft 11 of the engine 10 and the rotating electrical machine shaft 26 based on the hydraulic pressure of the hydraulic circuit. The hydraulic circuit of the engine-side clutch 24 is connected to, for example, a hybrid ECU 91, and the engagement state of the engine-side clutch 24 is switched under the control of the hybrid ECU 91.

[0017] The above-described rotating electric machine unit 20 rotates the rotating electric machine shaft 26 by controlling the drive of the inverter 80 by the control device 90. The rotating electric machine unit 20 generates a rotational driving force for traveling in the rotating electric machine shaft 26 by using the electric power supplied from the inverter 80 instead of or in addition to the engine 10. The rotating electric machine unit 20 also generates electric power by the rotational drive of the engine 10 or by using a driven force input from the drive wheels (not shown). The electric power generated by the rotating electric machine unit 20 is stored in the battery 50 via the inverter 80.

[0018] The transmission unit 30 is configured as a stepped type having a plurality of predetermined gears, for example, and switches to an appropriate gear to reduce the rotational driving force of the rotating electric machine shaft 26. As an example, the transmission unit 30 includes a torque converter 31 and an automatic transmission unit 36.

[0019] The torque converter 31 is a fluid-type power transmission device that transmits power via a fluid. The torque converter 31 includes a pump impeller 32 on the input shaft side, a turbine runner 33 on the output shaft side, and a stator 34 that amplifies torque. The torque converter 31 transmits power via a fluid between the pump impeller 32 and the turbine runner 33. The torque converter 31 is also provided with a lock-up clutch 35 that connects the input shaft side and the output shaft side of the torque converter 31 directly or in a slip state.

[0020] The pump impeller 32 is connected to the rotating electric machine shaft 26 and rotates within the housing of the transmission unit 30 as the rotating electric machine shaft 26 rotates. The turbine runner 33 has a turbine shaft 331 at its center and rotates the turbine shaft 331 under the action of the rotation of the pump impeller 32 and the stator 34.

[0021] The lock-up clutch 35 is a hydraulic friction clutch that is frictionally engaged by being controlled by a hydraulic circuit (not shown). The operating states of the torque converter 31 include a disengaged state in which the lock-up clutch 35 is released, a semi-engaged state in which the lock-up clutch 35 is engaged with slippage, and an engaged state in which the lock-up clutch 35 is fully engaged. For example, when the lock-up clutch 35 is engaged, the pump impeller 32 and the turbine runner 33 rotate together, and the rotational drive of the rotating electric machine shaft 26 is transmitted to the automatic transmission unit 36.

[0022] The automatic transmission unit 36 ​​has a plurality of hydraulic friction engagement elements and a planetary gear device (not shown). The automatic transmission unit 36 ​​selectively establishes a plurality of gear stages by selectively engaging the plurality of friction engagement elements. An input shaft of the automatic transmission unit 36 ​​is connected to a turbine shaft 331 of the torque converter 31. An output shaft 37 of the automatic transmission unit 36 ​​is connected to a transfer unit 40.

[0023] Transfer unit 40 distributes and transmits the rotational driving force received from output shaft 37 of automatic transmission unit 36 ​​to the drive wheels of hybrid vehicle 100. The drive wheels of hybrid vehicle 100 may be either a pair of front wheels or a pair of rear wheels, or both a pair of front wheels and a pair of rear wheels.

[0024] Battery 50 is the main power storage device of hybrid vehicle 100, supplying stored electric power to rotating electric machine unit 20 and storing electric power regenerated by rotating electric machine unit 20. The voltage of battery 50 is set to a voltage higher than the voltage of auxiliary battery 55 in order to drive and rotate rotating electric machine unit 20. Travel drive device 1 connects battery 50 and inverter 80 of rotating electric machine unit 20 via high-voltage wiring 51.

[0025] The system main relay 60 is installed at a midpoint of the high-voltage wiring 51. The system main relay 60 is capable of communicating with the hybrid ECU 91, and switches between connection and disconnection (cutting off, disconnection) of the battery 50 in the high-voltage wiring 51 based on commands from the hybrid ECU 91. For example, the system main relay 60 is configured to have a positive relay in the positive line of the high-voltage wiring 51 and a negative relay in the negative line of the high-voltage wiring 51.

[0026] The auxiliary battery 55 is a power storage device that supplies power to various electrical and electronic devices of the hybrid vehicle 100. The auxiliary battery 55 is connected to, for example, the starter motor 12, the DC-DC converter 70, etc., and supplies power to these devices at appropriate times. The auxiliary battery 55 is also connected to the alternator 14 of the engine 10, and stores the power generated by the alternator 14.

[0027] The DC-DC converter 70 is provided on a wiring that connects the auxiliary battery 55 to a high-voltage wiring 51 that extends between the system main relay 60 and the inverter 80. In other words, the DC-DC converter 70 is electrically connected to the system main relay 60. The DC-DC converter 70 changes the voltage between the auxiliary battery 55 and the high-voltage wiring 51 to enable the transfer of power. For example, the DC-DC converter 70 boosts the supply voltage of the auxiliary battery 55 and supplies it to the high-voltage wiring 51. Alternatively, the DC-DC converter 70 reduces the voltage from the high-voltage wiring 51 and supplies it to the auxiliary battery 55.

[0028] The DC-DC converter 70 also includes a diagnostic unit 71 that diagnoses abnormalities in the DC-DC converter 70. Abnormalities in the DC-DC converter 70 include element failure due to aging or overcurrent, and activation of a protection circuit due to overload. For example, the diagnostic unit 71 may be provided within the DC-DC converter 70 and include a voltmeter that detects the output voltage and / or input voltage of the DC-DC converter 70 and a processing unit that diagnoses normality or abnormality based on the information detected by the voltmeter. The diagnostic unit 71 may also appropriately employ a well-known abnormality detection method capable of detecting the state of the DC-DC converter 70 and a configuration used for this abnormality detection method. The diagnostic unit 71 is communicably connected to the control device 90 (hybrid ECU 91) and transmits diagnostic information diagnosed in the DC-DC converter 70 to the hybrid ECU 91. Note that the diagnostic unit 71 is not limited to being provided in the DC-DC converter 70; for example, a part or all of the diagnostic unit 71 may be provided on the control device 90 side.

[0029] The inverter 80 converts the DC power supplied from the battery 50 into three-phase AC power and supplies it to the rotating electrical machine unit 20. The inverter 80 also converts the AC power generated by the rotating electrical machine unit 20 into DC power and supplies it to the battery 50. This allows the battery 50 to store the power output from the inverter 80.

[0030] The hybrid ECU 91 and the engine ECU 92 are electronic circuits having a processor, memory, input / output interface, communication interface, etc. (not shown). The processor is one or a combination of a central processing unit (CPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a circuit made up of a plurality of discrete semiconductors, etc. The memory includes a main storage device made up of semiconductor memory such as random access memory (RAM) and read only memory (ROM), and an auxiliary storage device made up of a disk, semiconductor memory (flash memory), etc.

[0031] The hybrid ECU 91 mainly controls the configuration related to the combination of the engine 10 and the rotating electrical machine unit 20 by having a processor read and process programs stored in a memory. The hybrid ECU 91 is connected to, for example, the hydraulic circuit of the engine-side clutch 24 of the rotating electrical machine unit 20, the ECU of the battery 50, the control unit of the system main relay 60, the control unit of the DC-DC converter 70, and the control unit of the inverter 80. The hybrid ECU 91 operates each of the connected components by outputting commands to each of the connected components at appropriate timing.

[0032] The engine ECU 92 mainly controls the operation of the engine 10 and the configurations whose operations are switched in conjunction with the operation of the engine 10 by having a processor read and process programs stored in memory. The engine ECU 92 is connected to sensors related to the control of the engine 10 (such as an accelerator opening sensor 93 that detects the accelerator operation by the user), and rotates the engine 10 in response to the user's operation and commands from the hybrid ECU 91. The engine ECU 92 is also connected to, for example, control units for the electronic throttle and ignition plugs of the engine 10, a driver for the starter motor 12, a control unit for the alternator 14, and a control unit for the transmission unit 30. The engine ECU 92 operates each of the connected components by outputting commands to each of the connected components at appropriate timing.

[0033] Although the control device 90 according to the embodiment includes the hybrid ECU 91 and the engine ECU 92, these ECUs may be integrated into an electronic circuit. Alternatively, the control device 90 may be configured to include a plurality of ECUs obtained by further dividing the hybrid ECU 91 and the engine ECU 92.

[0034] The system main relay 60 may experience abnormalities such as welding of the relay contacts due to the influence of current flowing through the internal relays (positive relay, negative relay). Therefore, during the startup sequence for starting the traveling drive device 1, the control device 90 controls the drive or stop of the DC-DC converter 70 before connecting the system main relay 60, thereby diagnosing the welding state of the system main relay 60. The welding check for the system main relay 60 is performed by using power supplied from the auxiliary battery 55, without using power from the battery 50. Examples of this welding inspection method include the control disclosed in the above-mentioned prior art (JP 2020-99129 A). The control device 90 then connects the system main relay 60 when the system main relay 60 is in a normal state, i.e., when it is not welded. This allows the hybrid vehicle 100 to supply power from the battery 50 to the rotating electrical machine unit 20 or store regenerative power from the rotating electrical machine unit 20 in the battery 50.

[0035] However, the above-described welding check of the system main relay 60 requires that the DC-DC converter 70 is operating normally, because power is supplied to the system main relay 60 from the auxiliary battery 55 via the DC-DC converter 70. If an abnormality occurs in the DC-DC converter 70, the welding check of the system main relay 60 cannot be safely performed. For this reason, conventional driving devices have been controlled to stop the start-up sequence when an abnormality occurs in the DC-DC converter.

[0036] However, it is desirable that the hybrid vehicle 100 be able to perform evacuation running to move the vehicle to a safe place or a repair shop, etc., even if an abnormality occurs in the DC-DC converter 70. The hybrid vehicle 100 according to the embodiment is able to perform this evacuation running by performing appropriate processing when an abnormality in the DC-DC converter 70 is detected.

[0037] Control at the time of starting up the hybrid vehicle 100 (a method for starting up the hybrid vehicle 100) will be described below with reference to Fig. 2. Fig. 2 is a flowchart showing an example of a method for starting up the hybrid vehicle 100.

[0038] In the method for starting hybrid vehicle 100, control device 90 sequentially controls the processing flow of steps S101 to S108 shown in FIG.

[0039] Specifically, the hybrid ECU 91 of the control device 90 acquires a signal indicating that the user of the hybrid vehicle 100 has turned on the ignition (step S101).

[0040] When the hybrid ECU 91 starts the startup sequence of the traveling drive device 1, it first starts up the engine ECU 92, the DC-DC converter 70, etc. using the power of the auxiliary battery 55 (step S102). At this time, the hybrid ECU 91 does not connect the system main relay 60 (keeps it disconnected).

[0041] Next, the hybrid ECU 91 operates the DC-DC converter 70 and causes the diagnosing unit 71 to diagnose the state (normal or abnormal) of the DC-DC converter 70 (step S103). The hybrid ECU 91 acquires the diagnostic information of the diagnosing unit 71. However, the diagnosis of abnormality by the diagnosing unit 71 may be performed in advance when the traveling drive device 1 is stopped or traveling, and the diagnostic result may be read out at startup.

[0042] Based on the acquired diagnostic information, the hybrid ECU 91 determines whether or not an abnormality has occurred in the DC-DC converter 70 (step S104). If the DC-DC converter 70 is normal (step S104: NO), the process proceeds to step S105, whereas if the DC-DC converter 70 is abnormal (step S104: YES), the process proceeds to step S107.

[0043] If the DC-DC converter 70 is normal, it can be said that the welding check of the system main relay 60 can be safely performed based on the operation of the DC-DC converter 70. Therefore, in step S105, the hybrid ECU 91 executes the welding check of the system main relay 60.

[0044] If the system main relay 60 is not welded after the welding check of the system main relay 60 is completed, the hybrid ECU 91 performs a normal startup in which the system main relay 60 connects the battery 50 and the inverter 80 (step S106). This allows the traveling drive device 1 to perform normal traveling by, for example, supplying power from the battery 50 to the rotating electrical machine unit 20.

[0045] On the other hand, if the DC-DC converter 70 is abnormal in step S104, it can be said that the welding check of the system main relay 60 cannot be safely performed. Therefore, in step S107, the hybrid ECU 91 executes activation for performing evacuation running. Specifically, the hybrid ECU 91 maintains the disconnection of the system main relay 60. At this time, the hybrid ECU 91 may also stop driving the DC-DC converter 70. Then, the hybrid ECU 91 communicates with the engine ECU 92, and the engine ECU 92 drives the starter motor 12 to start the engine 10. Furthermore, the engine ECU 92 operates the electronic throttle, spark plugs, etc. of the engine 10 to rotate and drive the engine 10.

[0046] The rotational driving of engine 10 causes alternator 14 to generate electricity, and this generated electricity is stored in auxiliary battery 55 (step S108). This prevents auxiliary battery 55 from running out of power, and allows hybrid vehicle 100 to run until gasoline runs out.

[0047] As described above, the hybrid vehicle 100 according to this embodiment can operate the engine 10 and perform evacuation running even when an abnormality occurs in the DC-DC converter 70. This allows the hybrid vehicle 100 to be moved to a safe location, a repair shop, or the like, and appropriate measures can be easily taken. In particular, the hybrid vehicle 100 can immediately transition to evacuation running because it does not check for welding of the system main relay 60 when an abnormality in the DC-DC converter 70 is diagnosed. Furthermore, by not connecting the system main relay 60 when an abnormality occurs in the DC-DC converter 70, the hybrid vehicle 100 can prevent double failures, such as a failure of the DC-DC converter 70 and welding of the relay, before they occur.

[0048] The hybrid vehicle 100 is not limited to the configuration of the above-described embodiment, and various modifications are possible. For example, the hybrid vehicle 100 is not limited to a one-motor hybrid, and may be a traveling drive device equipped with a plurality of motor generators (rotating electric machine unit 20), such as a two-motor hybrid.

[0049] The hybrid vehicle 100 according to the presently disclosed embodiment is illustrative in all respects and not restrictive. The embodiment may be modified and improved in various ways without departing from the spirit and scope of the appended claims. The features described in the above-described embodiments may be configured differently and may be combined within a consistent range. [Explanation of symbols]

[0050] 10 Engine 12 Starter motor 14 Alternator 20 Rotating Electric Machinery Department 50 Battery 60 System Main Relay 70 DC-DC converter 71 Diagnostic Department 90 Control device 100 Hybrid Vehicles

Claims

[Claim 1] A hybrid vehicle equipped with an engine and a rotating electrical machine unit, a battery that supplies power to the rotating electrical machine unit; a system main relay that switches between connection and disconnection between the rotating electrical machine unit and the battery; a DC-DC converter electrically connected to the system main relay; a diagnostic unit that diagnoses whether the DC-DC converter is normal or abnormal; a control device; The engine includes a starter motor that starts the rotational driving of the engine, and an alternator that generates electricity based on the rotational driving of the engine, When the control device diagnoses the DC-DC converter using the diagnostic unit at the time of startup and detects an abnormality in the DC-DC converter, the control device disconnects the system main relay, starts the engine using the starter motor, and causes the alternator to generate electricity based on the rotational drive of the engine. Hybrid vehicle.

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