Hybrid vehicle

Abstract

The invention provides a hybrid vehicle. When an ignition switch is turned on, starting processing of a driving device of a motor is performed more reliably. A hybrid vehicle is provided with a drive device for driving an electric motor which is connected to a low-voltage-side power line connected to a low-voltage battery via a motor relay and which exchanges power input / output to an output shaft of an engine with power input / output by a high-voltage-side power line connected to a high-voltage battery, when the ignition switch is turned on, the motor relay is turned on after the completion of cranking by the starter motor engine is confirmed.

Description

Technical Field

[0001] This disclosure relates to hybrid vehicles, and more specifically, to hybrid vehicles having an electric motor that inputs and outputs power relative to the output shaft of an engine and a starter motor that starts the engine. Background Technology

[0002] Conventionally, in hybrid vehicles of this type, an example has been proposed where, during engine restart, a first relay is deactivated and a second relay is energized, a second load is connected to the main power supply via a DC / DC converter, and the first load is connected to the auxiliary power supply via a regulator (see, for example, Patent Document 1). In this hybrid vehicle, a redundant power system is provided that can maintain a backup function for the normal load during engine restart after idling stop.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-026215 Summary of the Invention

[0006] In hybrid vehicles equipped with an electric motor that inputs and outputs power relative to the engine's output shaft and a starter motor that starts the engine, when the ignition switch is turned on, the electric motor is activated by a relay to start the drive unit in order to start the engine via the starter motor and begin supplying power to the electric motor's drive unit. The power supply to the starter motor also occurs through a low-voltage battery and the power supply to the drive unit. Therefore, when the electric motor is activated by the relay during start-up via the starter motor, the output voltage of the low-voltage battery may sometimes drop, causing abnormalities in the starting of the drive unit.

[0007] The main objective of the hybrid vehicle disclosed herein is to more reliably initiate the starting process of the electric motor drive unit when the ignition switch is turned on.

[0008] The hybrid vehicle disclosed herein employs the following means to achieve the aforementioned main objectives.

[0009] The hybrid vehicle disclosed herein is characterized by having:

[0010] An engine; a high-voltage battery; a low-voltage battery; an electric motor that exchanges power with a high-voltage side power line connected to the high-voltage battery, and inputs and outputs power relative to the output shaft of the engine; a starter motor that receives power from a low-voltage side power line connected to the low-voltage battery to start the engine; a DC / DC converter connected to both the high-voltage and low-voltage side power lines, exchanging power between the two power lines as voltage changes occur; a drive unit connected to the low-voltage side power line via a motor relay to drive the electric motor; and a control unit that switches the motor relay on and off, wherein...

[0011] When the ignition switch is turned on, the control device activates the electric motor via a relay after confirming that the engine has started through the starter motor.

[0012] In the hybrid vehicle disclosed herein, the electric motor is switched on via a relay after the engine start-up via the starter motor has been confirmed to be complete when the ignition switch is turned on. This avoids potential anomalies caused by voltage drops during engine start-up, where the electric motor is switched on via the relay to start the drive unit. As a result, the starting process of the electric motor drive unit can be performed more reliably when the ignition switch is turned on.

[0013] In the hybrid vehicle disclosed herein, the control unit can also be embedded in the DC / DC converter. That is, the DC / DC converter can also be used to switch the relay for the electric motor on and off. In this case, the DC / DC converter can also receive a signal from other control units indicating that the engine has started via the starter motor when the ignition switch is turned on, and upon receiving this signal, it can turn on the relay for the electric motor. Attached Figure Description

[0014] Figure 1 This is a structural diagram that schematically illustrates the structure of a hybrid vehicle 20 as one embodiment of the present invention.

[0015] Figure 2 This is a flowchart illustrating an example of the ignition on-time processing performed by the DC / DC converter 68 when the ignition switch 80 is turned on. Detailed Implementation

[0016] Next, the specific implementation method will be described (implementation method). Figure 1This is a structural diagram that schematically illustrates the structure of a hybrid vehicle 20 as one embodiment of the present invention. As shown in the figure, the hybrid vehicle 20 of this embodiment includes an engine 22, a starter motor 25, a motor 30, a motor drive assembly (hereinafter referred to as "MG assembly") 32, an automatic transmission 40, a high-voltage battery 60, a low-voltage battery 67, a DC / DC converter 68, and a main electronic control unit (hereinafter referred to as "main ECU") 70.

[0017] Engine 22 is configured as a multi-cylinder (4-cylinder, 6-cylinder, etc.) internal combustion engine that uses gasoline, light oil, etc. supplied from the fuel tank via the fuel supply system as fuel and outputs power through each stroke of intake, compression, expansion (combustion), and exhaust. Engine 22 is controlled by an engine electronic control unit (hereinafter referred to as "engine ECU") 24.

[0018] Although not shown, the engine ECU 24 is configured as a CPU-centric microprocessor. Signals from various sensors required for controlling the operation of the engine 22 are input to the engine ECU 24, and various control signals for controlling the operation of the engine 22 are output from the engine ECU 24.

[0019] A starter motor 25 for starting the engine 22 is connected to the crankshaft 23, which serves as the output shaft of the engine 22. Additionally, the input side of a shock absorber 28, which acts as a torsional element, is also connected to the crankshaft 23 of the engine 22. A pulley 23b is mounted on the crankshaft 23 of the engine 22.

[0020] Motor 30 is configured, for example, as a synchronous generator motor. A pulley 30b is mounted on the rotating shaft of motor 30. A belt 31 is rotatably driven by a pulley 23b mounted on crankshaft 23 of engine 22 on pulley 30b.

[0021] The MG assembly 32 includes an inverter 33 and a motor electronic control unit (hereinafter referred to as "MGECU") 34. The inverter 33 is used to drive the motor 30 and is connected to the high-voltage side power line 61. Although not shown, the MGECU 34 is configured as a CPU-centric microprocessor. Signals from various sensors required for driving control of the motor 30, such as the rotational position φm of the rotor of the motor 30 detected by a rotational position sensor (not shown), are input to the MGECU 34. Switching control signals are output from the MGECU 34 to the inverter 33 to switch multiple switching elements of the inverter 33 that drive the motor 30. The motor 30 is driven to rotate by the switching control of the multiple switching elements of the inverter 33 by the MGECU 34.

[0022] The automatic transmission 40 includes a torque converter 43, a 6-speed automatic transmission 45, and a hydraulic circuit (not shown). The torque converter 43 is configured as a general fluid-type transmission device, amplifying the torque and transmitting power from the input shaft 41 (connected to the rotating shaft of the motor 30) to the intermediate rotating shaft 44 (which serves as the input shaft of the automatic transmission 45), or transmitting the torque as is without amplification. The automatic transmission 45 is connected to the intermediate rotating shaft 44 and to the output shaft 42 (connected to the drive shaft 46), and has multiple planetary gears and multiple hydraulically driven friction engagement elements (clutches, brakes). Furthermore, the drive shaft 46 is connected to the rear wheels 55a and 55b via an axle 56 and a rear differential gear 57. The automatic transmission 45, for example, forms forward gears (1st to 6th gears) and reverse gears by engaging and disengaging the multiple friction engagement elements, transmitting power between the intermediate rotating shaft 44 and the output shaft 42.

[0023] The high-voltage battery 60, such as a lithium-ion or nickel-metal hydride rechargeable battery, is connected to the high-voltage side power line 61 connected to the inverter 33. The low-voltage battery 67, such as a lead-acid battery with a lower rated voltage than the high-voltage battery 60, is connected to the low-voltage side power line 66 connected to the starter motor 25. The low-voltage side power line 66 is connected to the MG ECU 34 via the MG relay 34. A DC / DC converter 68 is connected to both the high-voltage side power line 61 and the low-voltage side power line 66. This DC / DC converter 68, controlled by the main ECU 70, steps down the power from the high-voltage side power line 61 and supplies it to the low-voltage side power line 66. Additionally, the DC / DC converter 68 can switch the MG relay 35 on and off as needed.

[0024] Although not shown, the main ECU 70 is configured as a microprocessor centered on a CPU. Signals from various sensors are input to the main ECU 70. Examples of signals input to the main ECU 70 include, for example, the rotational speed Np of the drive shaft 46 from the speed sensor 46a mounted on the drive shaft 46, the battery temperature Tb from the temperature sensor 60a mounted on the high-voltage battery 60, the voltage Vh of the high-voltage battery 60 from a voltage sensor (not shown) mounted between the terminals of the high-voltage battery 60, the current Ih of the high-voltage battery 60 from a current sensor (not shown) mounted on the output terminal of the high-voltage battery 60, and the voltage Vb of the low-voltage battery 67 from a voltage sensor (not shown) mounted between the terminals of the low-voltage battery 67. Additionally, examples include the ignition signal from the ignition switch 80, the gear position SP from the gear shift sensor 82 which detects the operating position of the gear lever 81, the acceleration opening Acc from the accelerator pedal position sensor 84 which detects the amount of pressure applied to the accelerator pedal 83, the brake pedal position BP from the brake pedal position sensor 86 which detects the amount of pressure applied to the brake pedal 85, and the vehicle speed V from the vehicle speed sensor 88.

[0025] Various control signals are output from the main ECU 70. Examples of signals output from the main ECU 70 include control signals to the starter motor 25, control signals to the automatic transmission 40, and control signals to the DC / DC converter 68. The main ECU 70 communicates with the engine ECU 24 and the aforementioned ECU 34 of the MG120.

[0026] Next, the operation of the hybrid vehicle 20 configured in this way will be explained, particularly the processing of the DC / DC converter 68 when the ignition switch 80 is turned on. Furthermore, when the ignition switch 80 is turned on, the engine 22 is started. The engine 22 is started by supplying power to the starter motor 25 from the low-voltage battery 67, and using the starter motor 25 to start the engine 22. At this time, drive control of the starter motor 25 by the main ECU 70 and engine start control by the engine ECU 24 receiving the start control signal from the main ECU 70 are performed. Figure 2 This is a flowchart illustrating an example of the ignition on-time processing performed by the DC / DC converter 68 when the ignition switch 80 is turned on. This ignition on-time processing is performed when the ignition switch 80 is turned on.

[0027] After the ignition start-up process is executed, the DC / DC converter 68 determines whether there is a software update request for the MG assembly 32 (step S100). A request for an update to the MG assembly 32 software (including an update to the MGECU 34 software) is input by the dealership or other entity to the main ECU 70, which then notifies the DC / DC converter 68. When a software update request for the MG assembly 32 is determined to be present, the engine 22 does not need to be started; therefore, the MG relay 35 is activated (step S120), thereby initiating the start-up process for the MG assembly 32, including the MGECU 34, and ending this process. Afterwards, the software update for the started MGECU 34, etc., is performed.

[0028] If, in step S100, it is determined that there is no software update request for the MG assembly 32, the process waits for the engine 22 using the starter motor 25 to start (step S110), then turns on the MG relay 35 (step S120), thereby performing the start-up process of the MG assembly 32 including the MG ECU 34 and ending this process. Afterwards, by sending a control signal (torque command, etc.) to drive the motor 30 from the main ECU 70 to the MG ECU 34, the MG ECU 34, upon receiving the signal, performs drive control on the motor 30.

[0029] In the hybrid vehicle 20 described above, when the ignition switch 80 is turned on, the MG relay 35 is activated after the engine 22, which utilizes the starter motor 25, has completed starting, to initiate the starting process of the MG assembly 32, including the MG ECU 34. This avoids potential anomalies caused by voltage drops when the MG relay 35 is activated to start the MG assembly 32 during the process of starting the engine 22 via the starter motor 25, where the low-voltage battery 67 experiences a voltage drop. As a result, the starting process of the MG assembly 32 when the ignition switch 80 is turned on can be performed more reliably.

[0030] In the hybrid vehicle 20 of this embodiment, the MG relay 35 is switched on and off via the DC / DC converter 68, but it can also be switched on and off via the main ECU 70. In this case, the ignition start-up process can be handled by the main ECU 70.

[0031] In the hybrid vehicle 20 of the embodiment, it is set to determine whether there is a software update request for the MG assembly 32 when the ignition switch 80 is turned on. However, it is also possible not to determine whether there is a software update request for the MG assembly 32, and wait for the engine 22 using the starter motor 25 to start and turn on the MG relay 35.

[0032] This section explains the main elements of the implementation method and their correspondence with the main elements of the invention described in the invention description. In the implementation method, engine 22 is equivalent to "engine", high-voltage battery 60 is equivalent to "high-voltage battery", low-voltage battery 67 is equivalent to "low-voltage battery", motor 30 is equivalent to "electric motor", starter motor 25 is equivalent to "starter motor", DC / DC converter 68 is equivalent to "DC / DC converter", MG relay 35 is equivalent to "electric motor relay", MG assembly 32 is equivalent to "drive device", and DC / DC converter 68 is equivalent to "control device".

[0033] Furthermore, the correspondence between the main elements of the implementation method and the main elements of the invention described in the invention summary is merely an example used to specifically illustrate how the implementation method carries out the invention described in the invention summary, and therefore does not limit the elements of the invention described in the invention summary. That is, the interpretation of the invention described in the invention summary should be based on the description in that section, and the implementation method is merely a specific example of the invention described in the invention summary.

[0034] The above describes the embodiments of the present invention, but the present invention is not limited to such embodiments, and can of course be implemented in various ways without departing from the spirit of the present invention.

[0035] [Industry Applicability]

[0036] This invention can be used in the manufacturing industry of hybrid vehicles, etc.

[0037] (Symbol Explanation)

[0038] 20: Hybrid vehicle; 22: Engine; 23: Crankshaft; 23b: Pulley; 24: Engine ECU; 25: Starter motor; 28: Shock absorber; 30: Motor; 30b: Pulley; 31: Belt; 32: Drive unit; 32: MG assembly; 33: Inverter; 34: Motor electronic control unit (MG ECU); 35: MG relay; 40: Automatic transmission; 41: Input shaft; 46a: Speed ​​sensor; 42: Output shaft; 43: Torque converter; 44: Intermediate rotating shaft; 45: Automatic transmission; 46: Drive shaft; 55a: Rear wheel; 56: Axle; 57: Rear differential gear; 60: High-voltage battery; 61: High-voltage side power line; 66: Low-voltage side power line; 67: Low-voltage battery; 68: DC / DC converter; 70: Main electronic control unit (main ECU); 80: Ignition switch.

Claims

1. A hybrid vehicle, characterized in that, have: engine; High-voltage batteries; Low-voltage batteries; An electric motor, which exchanges power with a high-voltage side power line connected to the high-voltage battery, inputs and outputs power relative to the output shaft of the engine; The starter motor receives power from the low-voltage side power line connected to the low-voltage battery to start the engine. A DC / DC converter is connected to the high-voltage side power line and the low-voltage side power line, and exchanges power between the high-voltage side power line and the low-voltage side power line as the voltage changes. The drive unit is connected to the low-voltage side power line via a motor relay to drive the motor. as well as The control device switches the motor on and off using a relay, wherein... When the ignition switch is turned on, the control device activates the electric motor via a relay after confirming that the engine has started through the starter motor.

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