automobile

Abstract

To enable battery-less driving in the event of a failure of a high-voltage battery for motor driving.SOLUTION: An automobile comprises: an engine; a power-generable electric motor coupled to the engine; a high-voltage battery; a system main relay that disconnects the high-voltage battery; a high-voltage system electrical load connected to a high-voltage system power line; a low-voltage battery; a DC / DC converter connected to the low-voltage system power line and the high-voltage system power line; and a control device. When a failure occurs in the high-voltage battery, the control device stops the high-voltage system electrical load and the electric motor, then turns off the system main relay, after that, secures voltage on the high-voltage system power line, activates the electric motor, and uses power from the engine to generate electricity with the electric motor, thereby activating the high-voltage system electrical load and performing step-down driving by the DC / DC converter.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an automobile, and more particularly to an automobile including a power-generable electric motor connected to an output shaft of an engine, a high-voltage battery that supplies power to the electric motor, a high-voltage electrical load connected to a high-voltage power line, and a low-voltage battery having a voltage lower than that of the high-voltage battery.

Background Art

[0002] Conventionally, as this type of technology, there has been proposed an automobile having two motors connected to a power line connected to a high-voltage battery, and performing battery-less running by turning off a system main relay in the event of an abnormality in the high-voltage battery (see, for example, Patent Document 1). In this automobile, power is generated by using power from the engine by one motor, and all of this generated power is consumed by the other motor to enable battery-less running.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in an automobile having a configuration different from the configuration of the drive system of the above-described automobile, the same battery-less running cannot be performed. In an automobile including a power-generable electric motor connected to an output shaft of an engine, a high-voltage battery that supplies power to the electric motor, a high-voltage electrical load connected to a high-voltage power line, and a low-voltage battery having a voltage lower than that of the high-voltage battery, since there is only a single electric motor in the high-voltage power line, battery-less running by two electric motors becomes impossible. Therefore, battery-less running according to the configuration of the automobile is required.

[0005] The automobile of the present disclosure mainly aims to enable battery - less driving when a high - voltage battery fails in an automobile comprising a power - generating motor connected to the output shaft of an engine, a high - voltage battery for supplying power to the motor, a high - voltage electrical load connected to a high - voltage power line, and a low - voltage battery having a voltage lower than that of the high - voltage battery.

Means for Solving the Problems

[0006] The automobile of the present disclosure has adopted the following means to achieve the above - mentioned main purpose.

[0007] The automobile of the present disclosure comprises an engine, a power - generating motor connected to the output shaft of the engine, a high - voltage battery for supplying power to the motor, a system main relay attached to a high - voltage power line connected to the high - voltage battery, a high - voltage electrical load connected to the high - voltage power line, a low - voltage battery having a voltage lower than that of the high - voltage battery, a DC / DC converter connected to a low - voltage power line connected to the low - voltage battery and the high - voltage power line, a control device for controlling the engine, the motor, and the DC / DC converter, and is an automobile characterized in that when a failure occurs in the high - voltage battery, the control device turns off the system main relay after stopping the high - voltage electrical load and the motor, and then secures the voltage of the high - voltage power line to start the motor, generates electricity by the motor using the power from the engine, and starts the high - voltage electrical load and performs step - down driving by the DC / DC converter. It is characterized by the above.

[0008] The motor vehicle of the present disclosure includes an engine, a power-generable electric motor connected to the output shaft of the engine, a high-voltage battery that supplies power to the electric motor, a system main relay attached to a high-voltage system power line connected to the high-voltage battery, a high-voltage system electrical load connected to the high-voltage system power line, a low-voltage battery having a voltage lower than that of the high-voltage battery, a low-voltage system power line connected to the low-voltage battery, a DC / DC converter connected to the high-voltage system power line, and a control device that controls the engine, the electric motor, and the DC / DC converter. When a failure occurs in the high-voltage battery, the control device turns off the system main relay after stopping the high-voltage system electrical load and the electric motor, and then secures the voltage of the high-voltage system power line to start the electric motor, generates electricity by the electric motor using the power from the engine, and starts the high-voltage system electrical load and performs step-down driving by the DC / DC converter. Thereby, it is possible to enable running in a state where the high-voltage battery is disconnected (battery-less running).

[0009] In the motor vehicle of the present disclosure, when the residual voltage of the high-voltage power line is sufficient to start the motor after turning off the system main relay, the control device starts the motor using the residual voltage of the high-voltage power line. When the residual voltage of the high-voltage power line is insufficient to start the motor after turning off the system main relay, the control device may secure the voltage of the high-voltage power line based on the state of the low-voltage battery to start the motor. In this way, the motor can be started more reliably after turning off the system main relay and cutting off the high-voltage battery. In this case, when the residual voltage of the high-voltage power line is insufficient to start the motor after turning off the system main relay, if the state of the low-voltage battery is good, the control device boosts the power of the low-voltage power line by the DC / DC converter and supplies it to the high-voltage power line to secure the voltage of the high-voltage power line and start the motor. When the state of the low-voltage battery is not good, the control device may increase the engine speed to drive the motor and increase the back electromotive voltage to secure the voltage of the high-voltage power line and start the motor. In this way, the motor can be started more reliably.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0011] Next, embodiments for implementing the present disclosure will be described. FIG. 1 is a configuration diagram showing an outline of the configuration of an automobile 20 as an embodiment of the present disclosure. As shown in the figure, the automobile 20 of the embodiment includes an engine 22, a starter motor 25, a motor 30, an inverter 32, an automatic transmission 40, a high-voltage battery 60, a high-voltage electrical load 64, a low-voltage battery 67, a DC / DC converter 68, and a main electronic control unit (hereinafter referred to as "main ECU") 70.

[0012] The engine 22 is configured as a multi-cylinder (such as 4 cylinders or 6 cylinders) internal combustion engine that outputs power through intake, compression, expansion (explosion combustion), and exhaust strokes using gasoline, light oil, etc. supplied from a fuel tank via a fuel supply system as fuel. The engine 22 is operationally controlled by an engine electronic control unit (hereinafter referred to as "engine ECU") 24.

[0013] Although not shown, the engine ECU 24 is configured as a microprocessor centered on a CPU, and in addition to the CPU, it includes a ROM that stores a processing program, a RAM that temporarily stores data, an input / output port, and a communication port. Signals from various sensors necessary for operationally controlling the engine 22 are input to the engine ECU 24 via the input port, and various control signals for operationally controlling the engine 22 are output from the engine ECU 24 via the output port.

[0014] A starter motor 25 for cranking the engine 22 is connected to a crankshaft 23 as an output shaft of the engine 22. Also, the input side of a damper 28 as a torsional element is connected to the crankshaft 23 of the engine 22. A pulley 23b is attached to the crankshaft 23 of the engine 22.

[0015] The motor 30 is configured as a synchronous generator motor, for example. A pulley 30b is attached to the rotating shaft of the motor 30. A belt 31 is looped around the pulley 30b so as to be able to rotationally drive a pulley 23b attached to the crankshaft 23 of the engine 22. The inverter 32 is used to drive the motor 30 and is connected to the high-voltage power line 61. The motor 30 is rotationally driven by the main ECU 70 controlling the switching of a plurality of switching elements of the inverter 32.

[0016] The automatic transmission 40 includes a torque converter 43, a six-speed automatic transmission 45, and a hydraulic circuit (not shown). The torque converter 43 is configured as a general fluid-type transmission device and transmits the power of the input shaft 41 connected to the rotating shaft of the motor 30 to the intermediate rotating shaft 44, which is the input shaft of the automatic transmission 45, after amplifying the torque, or transmits it as it is without amplifying the torque. 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 a plurality of planetary gears and a plurality of hydraulically driven friction engagement elements (clutches, brakes). The drive shaft 46 is connected to the rear wheels 55a and 55b via an axle 56 and a rear differential gear 57. This automatic transmission 45 forms forward and reverse gears from the first speed to the sixth speed by engaging and disengaging a plurality of friction engagement elements, for example, and transmits power between the intermediate rotating shaft 44 and the output shaft 42.

[0017] The high-voltage battery 60 uses, for example, a lithium-ion battery or a nickel-metal hydride battery with a rated voltage of 48V and is connected to the high-voltage power line 61 connected to the inverter 32. A system main relay 62 is attached to the high-voltage power line 61, and the high-voltage battery 60 can be disconnected by turning off the system main relay 62. A high-voltage electrical load 64, such as a compressor of an air conditioner for conditioning the passenger compartment, is attached to the high-voltage power line 61. A smoothing capacitor 63 is also attached to the high-voltage power line 61.

[0018] The low-voltage battery 67 is, for example, a lead battery with a rated voltage of 12V, which is lower than that of the high-voltage battery 60, and is connected to the low-voltage power line 66 connected to the starter motor 25.

[0019] The DC / DC converter 68 is connected to the high-voltage power line 61 and the low-voltage power line 66. By being controlled by the main ECU 70, this DC / DC converter 68 steps down the power of the high-voltage power line 61 and supplies it to the low-voltage power line 66, or steps up the power of the low-voltage power line 66 and supplies it to the high-voltage power line 61. Usually, the DC / DC converter 68 steps down the power of the high-voltage power line 61 and supplies it to the low-voltage power line 66.

[0020] The main ECU 70 is configured as a microprocessor centered around a CPU, although not shown in the figure. In addition to the CPU, it includes a ROM for storing processing programs, a RAM for temporarily storing data, input / output ports, and communication ports. Signals from various sensors are input to the main ECU 70 via the input ports. Examples of signals input to the main ECU 70 include the rotational position φm of the rotor of the motor 30 from a rotational position sensor (not shown) that detects the rotational position of the rotor of the motor 30, the rotational speed Np of the drive shaft 46 from a rotational speed sensor 46a attached to the drive shaft 46, etc. Also, the battery temperature Tb from a temperature sensor 60a attached to the high-voltage battery 60, the voltage Vh of the high-voltage battery 60 from a voltage sensor (not shown) attached between the terminals of the high-voltage battery 60, the current Ih of the high-voltage battery 60 from a current sensor (not shown) attached to the output terminal of the high-voltage battery 60, the voltage VH (voltage of the smoothing capacitor 63) from a voltage sensor 63a attached to the high-voltage power line 61, and the voltage Vb of the low-voltage battery 67 from a voltage sensor (not shown) attached between the terminals of the low-voltage battery 67 can also be mentioned. Furthermore, the ignition signal from the ignition switch 80, the shift position SP from a shift position sensor 82 that detects the operating position of the shift lever 81, the accelerator opening Acc from an accelerator pedal position sensor 84 that detects the depression amount of the accelerator pedal 83, the brake pedal position BP from a brake pedal position sensor 86 that detects the depression amount of the brake pedal 85, and the vehicle speed V from a vehicle speed sensor 88 can also be mentioned.

[0021] Various control signals are output from the main ECU 70 via the output ports. Examples of signals output from the main ECU 70 include control signals to the starter motor 25, control signals to the inverter 32, control signals to the automatic transmission 40, control signals to the DC / DC converter 68, drive control signals to the system main relay 62, and control signals to the high-voltage electrical load 64. The main ECU 70 is connected to the engine ECU 24 via a communication port.

[0022] Next, the operation of the motor vehicle 20 of the embodiment configured in this way will be described, particularly the operation when a failure occurs in the high-voltage battery 60. FIG. 2 is a flowchart showing an example of the battery-less process executed by the main ECU 70 for battery-less driving when a failure occurs in the high-voltage battery 60.

[0023] When the battery-less process is executed, the main ECU 70 first determines whether a failure has occurred in the high-voltage battery 60 (step S100). When it is determined that no failure has occurred in the high-voltage battery 60, since battery-less driving is unnecessary, this process is terminated.

[0024] When it is determined in step S100 that a failure has occurred in the high-voltage battery 60, it is determined whether the high-voltage electrical load 64 is being driven (step S110). When it is determined that the high-voltage electrical load 64 is being driven, the driving of the high-voltage electrical load 64 is stopped (step S120). The significance of stopping the driving of the high-voltage electrical load 64 will be described later. Then, after the high-voltage electrical load 64 is not being driven or its driving has been stopped, the driving of the DC / DC converter 68 is stopped (step S130), and the driving of the motor 30 is stopped (step S140). The system main relay 62 is turned off to cut off the high-voltage battery 60 (step S150).

[0025] After cutting off the high-voltage battery 60, it is determined whether there is a residual voltage in the high-voltage system (step S160). The determination of whether there is a residual voltage in the high-voltage system can be made by detecting the voltage VH of the smoothing capacitor 63 (the voltage VH of the high-voltage system) by the voltage sensor 63a. When it is determined that there is a residual voltage in the high-voltage system, the motor 30 is started using the residual voltage of the high-voltage system (step S210). If the driving of the high-voltage electrical load 64 is continued even after the high-voltage battery 60 is cut off, the motor 30 cannot be started with the residual voltage of the high-voltage system. One of the significances of stopping the driving of the high-voltage electrical load 64 before cutting off the high-voltage battery 60 is to ensure the residual voltage of the high-voltage system and start the motor 30 more reliably.

[0026] When the motor 30 is started, power generation by the motor 30 using the power from the engine 22 is started (step S220), and a step-down operation of stepping down the power of the high-voltage power line 61 by the DC / DC converter 68 and supplying it to the low-voltage power line 66 is started (step S230). The high-voltage electrical load 64 is started (step S240), enabling battery-less driving. The battery-less driving is continued in this state. Then, waiting for the ignition switch 80 to be turned off (step S250), this process ends.

[0027] When it is determined in step S160 that there is no residual voltage in the high-voltage system, it is determined whether the voltage VL of the low-voltage system is stable and sufficient (step S170). The determination of whether the voltage VL of the low-voltage system is stable and sufficient can be made based on whether the voltage Vb of the low-voltage battery 67 holds the rated voltage. When it is determined that the voltage VL of the low-voltage system is stable and sufficient, a boosting operation of boosting the power of the low-voltage power line 66 by the DC / DC converter 68 and supplying it to the high-voltage power line 61 is performed (step S180). After the voltage of the high-voltage system has reached a sufficient level due to this boosting operation, the motor 30 is started (step S210). If the driving of the high-voltage electrical load 64 is continued even after the high-voltage battery 60 is disconnected, there may be a case where the voltage VH of the high-voltage system does not stabilize even when the boosting operation by the DC / DC converter 68 is performed, and the motor 30 may not be started. One of the significances of stopping the driving of the high-voltage electrical load 64 before disconnecting the high-voltage battery 60 is to stably ensure the voltage of the high-voltage system by the boosting operation of the DC / DC converter 68 and more reliably start the motor 30. Then, the processes of steps S220 to S240 are performed to enable battery-less driving, and waiting for the ignition switch 80 to be turned off (step S250), this process ends. Thereby, even when there is no residual voltage in the high-voltage system, the motor 30 can be started and battery-less driving can be performed.

[0028] When it is determined in step S170 that the voltage VL of the low-voltage system is insufficient, the engine 22 is controlled to increase the rotational speed Ne of the engine 22 (step S190), the counter electromotive force of the motor 30 driven by the engine 22 is increased (step S200), and the motor 30 is started after the voltage of the high-voltage system has reached a sufficient level due to the counter electromotive voltage (step S210). If the driving of the high-voltage system electrical load 64 is continued even after the high-voltage battery 60 is disconnected, the voltage will immediately drop due to the driving of the high-voltage system electrical load 64 even if the voltage VH of the high-voltage system is secured by the counter electromotive voltage of the motor 30, and there may be a case where the motor 30 cannot be started. One of the significances of stopping the driving of the high-voltage system electrical load 64 before disconnecting the high-voltage battery 60 is to stably secure the voltage of the high-voltage system by the counter electromotive voltage of the motor 30 and start the motor 30 more reliably. Then, the processes of steps S220 to S240 are performed to enable battery-less driving, and after waiting for the ignition switch 80 to be turned off (step S250), this process is terminated. Thereby, even when there is no residual voltage in the high-voltage system, the motor 30 can be started to perform battery-less driving.

[0029] In the automobile 20 of the embodiment described above, when a failure occurs in the high-voltage battery 60, after stopping the driving of the high-voltage system electrical load 64, the high-voltage battery 60 is disconnected, and then, the voltage of the high-voltage system is secured to start the motor 30, and power generation is performed by the motor 30 using the power from the engine 22 to start the high-voltage system electrical load 64 and perform a step-down operation by the DC / DC converter 68 to enable battery-less driving. Thereby, battery-less driving can be performed more reliably and stably when a failure occurs in the high-voltage battery 60.

[0030] In the motor vehicle 20 of the embodiment, after the high-voltage battery 60 is disconnected, when the residual voltage of the high-voltage system is sufficient to start the motor 30, the motor 30 is started using the residual voltage of the high-voltage system to enable battery-free driving. On the other hand, after the high-voltage battery 60 is disconnected, when the residual voltage of the high-voltage system is not sufficient to start the motor 30, the voltage of the high-voltage system is ensured according to the state of the voltage of the low-voltage system, and the motor 30 is started to enable battery-free driving. That is, when the voltage of the low-voltage system is stable and sufficient, the voltage of the high-voltage system is ensured by the boosting operation of the DC / DC converter 68, the motor 30 is started, and battery-free driving is enabled. When the voltage of the low-voltage system is not stable and sufficient, the engine speed is increased, and the voltage of the high-voltage system is ensured by the back electromotive force of the motor 30, and the motor 30 is started to enable battery-free driving. Thus, reliable and stable battery-free driving can be performed in the event of a failure of the high-voltage battery 60.

[0031] The correspondence between the main elements of the embodiment and the main elements of the invention described in the section of the means for solving the problems will be described. In the embodiment, the engine 22 corresponds to the "engine", the motor 30 corresponds to the "motor", the high-voltage battery 60 corresponds to the "high-voltage battery", the high-voltage system power line 61 corresponds to the "high-voltage system power line", the system main relay 62 corresponds to the "system main relay", the high-voltage system electrical load 64 corresponds to the "high-voltage system electrical load", the low-voltage battery 67 corresponds to the "low-voltage battery", the low-voltage system power line 66 corresponds to the "low-voltage system power line", the DC / DC converter 68 corresponds to the "DC / DC converter", and the main ECU 70 corresponds to the "control device".

[0032] Note that the correspondence between the main elements of the embodiment and the main elements of the invention described in the section of means for solving the problems is an example for specifically explaining the form for implementing the invention described in the section of means for solving the problems in the embodiment, and thus does not limit the elements of the invention described in the section of means for solving the problems. That is, the interpretation of the invention described in the section of means for solving the problems should be made based on the description in that section, and the embodiment is merely a specific example of the invention described in the section of means for solving the problems.

[0033] As described above, the present disclosure has been described using embodiments, but the present disclosure is not limited to such embodiments, and it goes without saying that it can be implemented in various forms without departing from the gist of the present disclosure.

Industrial Applicability

[0034] The present disclosure can be used in the manufacturing industry of automobiles and the like.

Description of Reference Numerals

[0035] 20 Automobile, 22 Engine, 23 Crankshaft, 23a Rotation Speed Sensor, 23b Pulley, 24 Engine ECU, 25 Starter Motor, 28 Damper, 30 Motor, 30b Pulley, 31 Belt, 32 Inverter, 40 Automatic Transmission, 41 Input Shaft, 46a Rotation Speed Sensor, 42 Output Shaft, 43 Torque Converter, 44 Intermediate Rotation 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, 62 System Main Relay, 63 Smoothing Capacitor, 63a Voltage Sensor, 64 High-Voltage System Electrical Load, 66 Low-Voltage Side Power Line, 67 Low-Voltage Battery, 68 DC / DC Converter, 70 Main Electronic Control Unit (Main ECU), 80 Ignition Switch, 81 Shift Lever, 82 Shift Position Sensor, 83 Accelerator Pedal, 84 Accelerator Pedal Position Sensor, 85 Brake Pedal, 86 Brake Pedal Position Sensor, 88 Vehicle Speed Sensor.

Claims

1. An engine, a motor capable of generating electricity connected to the output shaft of the engine, a high-voltage battery that supplies power to the motor, a system main relay attached to a high-voltage power line connected to the high-voltage battery, a high-voltage electrical load connected to the high-voltage power line, a low-voltage battery having a voltage lower than that of the high-voltage battery, a DC / DC converter connected to a low-voltage power line connected to the low-voltage battery and the high-voltage power line, a control device that controls the engine, the motor, and the DC / DC converter, An automobile comprising: When a failure occurs in the high-voltage battery, the control device turns off the system main relay after stopping the high-voltage electrical load and the motor, and then secures the voltage of the high-voltage power line to start the motor, generates electricity by the motor using the power from the engine, and starts the high-voltage electrical load and performs step-down driving by the DC / DC converter. An automobile characterized by the above.

2. The automobile according to claim 1, wherein the control device starts the motor using the residual voltage of the high-voltage power line when the residual voltage of the high-voltage power line is sufficient for starting the motor after turning off the system main relay, secures the voltage of the high-voltage power line based on the state of the low-voltage battery and starts the motor when the residual voltage of the high-voltage power line is insufficient for starting the motor after turning off the system main relay. An automobile.

3. The automobile according to claim 2, wherein when the residual voltage of the high-voltage power line is insufficient for starting the motor after turning off the system main relay, the control device secures the voltage of the high-voltage power line by boosting the power of the low-voltage power line by the DC / DC converter and supplying it to the high-voltage power line and starts the motor when the state of the low-voltage battery is good, and when the state of the low-voltage battery is not good, the control device increases the rotational speed of the engine to drive the motor around and increase the back electromotive voltage to secure the voltage of the high-voltage power line and start the motor. An automobile.

Images