Hybrid vehicle

Abstract

To properly cope with a system stop caused by a voltage drop of a low voltage system.SOLUTION: A hybrid vehicle includes: an engine; a starter motor; a low-voltage system that is connected to a low-voltage battery to supply electric power to the starter motor; a motor coupled to an output shaft of the engine; and a high-voltage system that is connected to a high-voltage battery to supply electric power to the motor. When a voltage of the low-voltage system returns to a predetermined voltage or higher after the voltage of the low-voltage system drops below the predetermined voltage while an ignition-on state is continuing, the hybrid vehicle releases a system stop and starts the system.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] Conventionally, as a hybrid vehicle of this kind, a hybrid vehicle that is made unable to run when the SOC of the power storage device is equal to or lower than a predetermined lower limit has been proposed (for example, see Patent Document 1). In this hybrid vehicle, before making the hybrid vehicle unable to run, the impossibility of EV running mode and the number of times the engine can be restarted are displayed. This prevents over-discharging of the power storage device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-111291 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a hybrid vehicle having a high-voltage system that supplies power to a motor connected to the output shaft of the engine and a low-voltage system that supplies power to a starter motor capable of cranking the engine, an excessive voltage drop may occur when the engine is cranked by the starter motor. Since various sensors attached to the hybrid vehicle are operated by power from the low-voltage system, when an excessive voltage drop occurs in the low-voltage system, the sensors do not operate normally, and the system is stopped to avoid detecting an abnormality. In this case, the voltage of the low-voltage system may recover after that, so it is not desirable to continue stopping the system.

[0005] The hybrid vehicle of the present disclosure has as its main object to more appropriately deal with a system shutdown caused by a voltage drop in the low voltage system. [Means for solving the problem]

[0006] The hybrid vehicle of the present disclosure employs the following measures to achieve the above-mentioned main object.

[0007] The hybrid vehicle of the present disclosure is A hybrid vehicle comprising: an engine; a starter motor for cranking the engine; a low voltage system connected to a low voltage battery to supply power to the starter motor; a motor coupled to an output shaft of the engine; a high voltage system connected to a high voltage battery having a higher voltage than the low voltage battery to supply power to the motor; a sensor that operates by receiving power from the low voltage system; and a control device that stops a system when the voltage of the low voltage system drops below a predetermined voltage when the engine is cranked by the starter motor in conjunction with an ignition being turned on, the control device, when the voltage of the low-voltage system drops below the predetermined voltage while the ignition is on and then returns to the predetermined voltage or higher, releases the system stop and starts the system. It is characterized by:

[0008] The hybrid vehicle disclosed herein includes an engine, a starter motor for cranking the engine, a low-voltage system connected to a low-voltage battery to supply power to the starter motor, a motor connected to an output shaft of the engine, a high-voltage system connected to a high-voltage battery having a higher voltage than the low-voltage battery to supply power to the motor, a sensor that operates by receiving power from the low-voltage system, and a control device that stops the system when the voltage of the low-voltage system drops below a predetermined voltage when the engine is cranked by the starter motor with the ignition on. When the voltage of the low-voltage system drops below the predetermined voltage while the ignition is on and then returns to the predetermined voltage or higher, the control device cancels the system stop and starts the system. This makes it possible to more appropriately deal with the system stop caused by the voltage drop in the low-voltage system. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram showing an outline of the configuration of a hybrid vehicle 20 according to an embodiment of the present invention. [Diagram 2] 11 is a flowchart showing an example of a system startup process executed by the main EUC 70. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Next, a mode (embodiment) for carrying out the present invention will be described. Fig. 1 is a schematic diagram showing the configuration of a hybrid vehicle 20 as one embodiment of the present invention. As shown in the figure, the hybrid vehicle 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 low-voltage battery 67, a DC / DC converter 68, and a main electronic control unit (hereinafter referred to as "main ECU") 70.

[0011] The engine 22 is configured as a multi-cylinder (4-cylinder, 6-cylinder, etc.) internal combustion engine that uses gasoline, diesel, etc. supplied from a fuel tank via a fuel supply system as fuel and outputs power through each of the intake, compression, expansion (explosive combustion), and exhaust strokes. The operation of the engine 22 is controlled by an engine electronic control unit (hereinafter referred to as "engine ECU") 24.

[0012] Although not shown, the engine ECU 24 is configured as a microprocessor centered on a CPU, and in addition to the CPU, includes a ROM for storing processing programs, a RAM for temporarily storing data, an input / output port, and a communication port. Signals from various sensors required for controlling the operation of the engine 22 are input to the engine ECU 24 via input ports, and various control signals for controlling the operation of the engine 22 are output from the engine ECU 24 via output ports.

[0013] A starter motor 25 for cranking the engine 22 is connected to the crankshaft 23 serving as the output shaft of the engine 22. The input side of a damper 28 serving as a torsion element is also connected to the crankshaft 23 of the engine 22. A pulley 23b is attached to the crankshaft 23 of the engine 22.

[0014] The motor 30 is configured as, for example, a synchronous generator motor. A pulley 30b is attached to a rotating shaft of the motor 30. A belt 31 is wound around the pulley 30b so as to rotate and 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 a high-voltage power line 61. The motor 30 is rotationally driven by the main ECU 70 controlling the switching of multiple switching elements of the inverter 32.

[0015] 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 amplifies the torque of the input shaft 41 connected to the rotating shaft of the motor 30 and transmits it to the intermediate rotating shaft 44, which is the input shaft of the automatic transmission 45, or transmits it without amplifying the torque. The automatic transmission 45 is connected to the output shaft 42, which is connected to the intermediate rotating shaft 44 and 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, 55b via an axle 56 and a rear differential gear 57. The automatic transmission 45 transmits power between the intermediate rotating shaft 44 and the output shaft 42, forming forward gears from 1st gear to 6th gear and reverse gears by engaging and disengaging the plurality of friction engagement elements, for example.

[0016] High-voltage battery 60 is, for example, a lithium-ion battery or a nickel-metal hydride battery, and is connected to high-voltage power line 61 that is connected to inverter 32. Low-voltage battery 67 is, for example, a lead battery having a lower rated voltage than high-voltage battery 60, and is connected to low-voltage power line 66 that is connected to starter motor 25. DC / DC converter 68 is connected to high-voltage power line 61 and low-voltage power line 66. DC / DC converter 68 is controlled by main ECU 70 to step down the power of high-voltage power line 61 and supply it to low-voltage power line 66. Hereinafter, the voltage system of high-voltage power line 61 may be referred to as a high-voltage system, and the voltage system of low-voltage power line 66 may be referred to as a low-voltage system.

[0017] Although not shown, the main ECU 70 is configured as a microprocessor centered on a CPU, and in addition to the CPU, includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port. Signals from various sensors are input to the main ECU 70 via the input port. Examples of signals input to the main ECU 70 include a 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, and a rotational speed Np of the drive shaft 46 from a rotational speed sensor 46a attached to the drive shaft 46. In addition, examples of signals input to the main ECU 70 include a battery temperature Tb from a temperature sensor 60a attached to the high-voltage battery 60, a voltage Vh of the high-voltage battery 60 from a voltage sensor (not shown) attached between the terminals of the high-voltage battery 60, a 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, and a voltage Vb of the low-voltage battery 67 from a voltage sensor (not shown) attached between the terminals of the low-voltage battery 67. Further examples include an ignition signal IG from an ignition switch 80, a shift position SP from a shift position sensor 82 that detects the operating position of a shift lever 81, an accelerator opening Acc from an accelerator pedal position sensor 84 that detects the amount of depression of an accelerator pedal 83, a brake pedal position BP from a brake pedal position sensor 86 that detects the amount of depression of a brake pedal 85, and a vehicle speed V from a vehicle speed sensor 88.

[0018] Various control signals are output from the main ECU 70 via an output port. Examples of signals output from the main ECU 70 include a control signal to the starter motor 25, a control signal to the inverter 32, a control signal to the automatic transmission 40, and a control signal to the DC / DC converter 68. The main ECU 70 is connected to the engine ECU 24 via a communication port.

[0019] Next, the operation of the hybrid vehicle 20 of the embodiment configured as described above, particularly the operation when the ignition signal IG is turned on by operating the ignition switch 80, will be described. Fig. 2 is a flowchart showing an example of a system startup process executed by the main ECU 70.

[0020] When the system startup process is executed, the main ECU 70 first determines whether the ignition signal IG is turned on (step S100). When the ignition signal IG is turned off, there is no need to start the system, so this process ends.

[0021] When it is determined in step S100 that the ignition signal IG is on, it is determined whether or not an excessive voltage drop has occurred in the voltage system (low voltage system) of the low-voltage side power line 66, resulting in a low voltage state (step S110). This determination can be made, for example, by checking whether or not the voltage of the low voltage system is below a threshold value. On the other hand, when it is determined that the low voltage system has not reached a low voltage state, the system activation is maintained if the system is activated, or the system is activated if it is not activated (step S130), and the process returns to the process of determining whether or not the ignition signal is on in step S100. In other words, when the voltage of the low voltage system is normal, the system activation state is maintained.

[0022] On the other hand, when it is determined in step S110 that an excessive voltage drop has occurred in the low-voltage system and the system has reached a low-voltage state, the system stop is maintained if the system is stopped, and the system is stopped if the system is activated (step S120), and the process returns to the process of determining whether the ignition signal is on in step S100. The system is stopped when the low-voltage system has reached a low-voltage state in order to prevent detection of an abnormality caused by a sensor operating with power from the low-voltage system not operating normally. Note that when the ignition signal IG is on and the low-voltage system continues to be in a low-voltage state, the processes of steps S100 to S120 are repeatedly executed to maintain the system stop, and thereafter, when the voltage of the low-voltage system is restored and the system recovers from the low-voltage state, the system is activated in step S130.

[0023] In the hybrid vehicle 20 of the present disclosure described above, even if an excessive voltage drop occurs in the low voltage system while the ignition signal is on, resulting in a low voltage state and causing the system to stop, the system will start up when the low voltage system recovers from the low voltage state. As a result, it is possible to more appropriately deal with the system stopping due to a voltage drop in the low voltage system.

[0024] The above describes the form for carrying out the present invention using an embodiment, but the present invention is not limited to such an embodiment in any way, and it goes without saying that the present invention can be carried out in various forms without departing from the gist of the present invention. [Industrial Applicability]

[0025] The present invention can be used in the hybrid vehicle manufacturing industry and the like. [Explanation of symbols]

[0026] 20 hybrid vehicle, 22 engine, 23 crankshaft, 24 engine ECU, 25 starter motor, 30 motor, 32 inverter, 40 automatic transmission, 46 drive shaft, 60 high voltage battery, 61 high voltage side power line, 66 low voltage side power line, 67 low voltage battery, 70 main electronic control unit (main ECU), 80 ignition switch, 81 shift lever, 82 shift position sensor.

Claims

[Claim 1] A hybrid vehicle comprising: an engine; a starter motor for cranking the engine; a low voltage system connected to a low voltage battery to supply power to the starter motor; a motor coupled to an output shaft of the engine; a high voltage system connected to a high voltage battery having a higher voltage than the low voltage battery to supply power to the motor; a sensor that operates by receiving power from the low voltage system; and a control device that stops a system when the voltage of the low voltage system drops below a predetermined voltage when the engine is cranked by the starter motor in conjunction with an ignition being turned on, the control device, when the voltage of the low-voltage system drops below the predetermined voltage while the ignition is on and then returns to the predetermined voltage or higher, releases the system stop and starts the system. A hybrid vehicle characterized by

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