Hybrid vehicles

Abstract

To more reliably perform start-up processing of a driving device for an electric motor when an ignition switch is turned on. [Solution] In a hybrid vehicle equipped with a drive device that drives an electric motor that is connected via an electric motor relay to a low-voltage power line connected to a low-voltage battery and that inputs and outputs power to the engine output shaft by exchanging power with a high-voltage power line connected to a high-voltage battery, when the ignition switch is turned on, the electric motor relay is turned on after confirming that the starter motor has completed cranking the engine.

Description

[Technical Field]

[0001] The present disclosure relates to a hybrid vehicle, and more particularly to a hybrid vehicle equipped with an electric motor that inputs and outputs power to and from an output shaft of an engine, and a starter motor that cranks the engine. [Background technology]

[0002] A conventional hybrid vehicle of this type has been proposed in which the engine restart process involves disconnecting the first relay and energizing the second relay to connect the second load to the main power supply via a DC / DC converter and connecting the first load to the auxiliary power supply via a regulator (see, for example, Patent Document 1).This hybrid vehicle has a redundant power supply system that can maintain a backup function for the normal load when the engine is restarted after an idle stop. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-026215 Summary of the Invention [Problem to be solved by the invention]

[0004] In a hybrid vehicle equipped with an electric motor that inputs and outputs power to the engine output shaft and a starter motor that cranks the engine, when the ignition switch is turned on, the engine is cranked by the starter motor and the electric motor relay is turned on to start supplying power to the electric motor drive device, thereby starting the drive device. Since power supply to the starter motor is also provided by the power supply to the drive device and the low-voltage battery, turning on the electric motor relay while cranking with the starter motor can cause a drop in the output voltage of the low-voltage battery, which can cause abnormalities in starting the drive device.

[0005] The hybrid vehicle of the present disclosure has as its main object the reliably performing the start-up process of the drive device for the electric motor when the ignition switch is turned on. [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 starter motor that receives power from a low-voltage power line connected to the low-voltage battery and cranks the engine; a DC / DC converter that is connected to the high-voltage power line and the low-voltage power line and exchanges power between the high-voltage power line and the low-voltage power line, and converts voltage between the high-voltage power line and the low-voltage power line; a drive unit that is connected to the low-voltage power line via a motor relay and drives the motor; and a control unit that turns the motor relay on and off, The control device is characterized in that when an ignition switch is turned on, the control device turns on the electric motor relay after confirming that cranking of the engine by the starter motor has been completed.

[0008] In the hybrid vehicle of the present disclosure, when the ignition switch is turned on, the motor relay is turned on after it is confirmed that the starter motor has completed cranking the engine, so that it is possible to avoid an abnormality that may occur due to a voltage drop when the motor relay is turned on to start the drive device during a voltage drop that occurs while the starter motor is cranking the engine, thereby making it possible to more reliably start up the drive device for the motor when the ignition switch is turned on.

[0009] In the hybrid vehicle of the present disclosure, the control device may be incorporated into the DC / DC converter. That is, the DC / DC converter may be configured to turn on and off the electric motor relay. In this case, the DC / DC converter may receive a signal from another control device indicating that engine cranking has been completed by the starter motor when the ignition switch is turned on, and turn on the electric motor relay after receiving the signal. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing the outline of the configuration of a hybrid vehicle 20 according to an embodiment of the present invention. [Figure 2] 10 is a flowchart showing an example of an ignition-on process executed by a DC / DC converter 68 when an ignition switch 80 is turned on. DETAILED DESCRIPTION OF THE INVENTION

[0011] Next, a mode (embodiment) for carrying out the present invention will be described. Fig. 1 is a configuration diagram showing an outline of 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, a motor drive device 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.

[0012] The engine 22 is configured as a multi-cylinder (four-cylinder, six-cylinder, etc.) internal combustion engine that uses gasoline, diesel, or the like as fuel supplied from a fuel tank via a fuel supply system and outputs power through 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.

[0013] Although not shown, the engine ECU 24 is configured as a microprocessor centered around a CPU. The engine ECU 24 receives signals from various sensors required for controlling the operation of the engine 22, and outputs various control signals for controlling the operation of the engine 22.

[0014] 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.

[0015] The motor 30 is configured as, for example, a synchronous generator motor. A pulley 30b is attached to the rotary 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.

[0016] The MG assembly 32 has 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 power line 61. Although not shown, the MGECU 34 is configured as a microprocessor centered around a CPU. Signals from various sensors required for driving and controlling the motor 30, such as the rotational position φm of the rotor of the motor 30, are input to the MGECU 34 from a rotational position sensor (not shown) that detects the rotational position of the rotor of the motor 30, are input to the MGECU 34, and the MGECU 34 outputs switching control signals to the inverter 33 for switching on and off multiple switching elements of the inverter 33 that drive the motor 30. The motor 30 is driven to rotate by the MGECU 34 controlling the switching of the multiple switching elements of the inverter 33.

[0017] 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 typical 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 an intermediate rotating shaft 44, which is the input shaft of the automatic transmission 45, or transmits the torque directly without amplifying it. The automatic transmission 45 is connected to the intermediate rotating shaft 44 and to an output shaft 42, which is connected to a drive shaft 46. The automatic transmission 45 has multiple planetary gears and multiple hydraulically driven friction engagement elements (clutches and brakes). The drive shaft 46 is connected to 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 (first through sixth gears) and reverse gears by engaging and disengaging the friction engagement elements, for example.

[0018] High-voltage battery 60 is, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery, and is connected to high-voltage power line 61 that is connected to inverter 33. 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. Low-voltage power line 66 is connected to MGECU 34 via MG relay 34. 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 on high-voltage power line 61 and supply the power to low-voltage power line 66. DC / DC converter 68 also turns MG relay 35 on and off as needed.

[0019] The main ECU 70 is configured as a microprocessor centered around a CPU (not shown). Signals from various sensors are input to the main ECU 70. Examples of signals input to the main ECU 70 include the rotation speed Np of the drive shaft 46 from a rotation speed sensor 46a attached to the drive shaft 46, 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, 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. Other examples include an ignition signal 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.

[0020] Various control signals are output from the main ECU 70. Examples of signals output from the main ECU 70 include a control signal to the starter motor 25, a control signal to the automatic transmission 40, and a control signal to the DC / DC converter 68. The main ECU 70 communicates with the engine ECU 24 and the ECU 34 of the MG 120.

[0021] Next, the operation of the hybrid vehicle 20 of this embodiment configured as described above, particularly the processing of the DC / DC converter 68 when the ignition switch 80 is turned on, will be described. When the ignition switch 80 is turned on, the engine 22 is started. The engine 22 is started by supplying power from the low-voltage battery 67 to the starter motor 25 and cranking the engine 22 with the starter motor 25. At this time, the main ECU 70 controls the drive of the starter motor 25, and the engine ECU 24 controls the engine start upon receiving a start control signal from the main ECU 70. Figure 2 is a flowchart showing an example of ignition-on processing executed by the DC / DC converter 68 when the ignition switch 80 is turned on. This ignition-on processing is executed when the ignition switch 80 is turned on.

[0022] When the ignition-on process is executed, the DC / DC converter 68 determines whether or not there is a request for updating the software of the MG assembly 32 (step S100). A request for updating the software of the MG assembly 32 (including updating the software of the MGECU 34) is input to the main ECU 70 by a dealer or the like, and the main ECU 70 notifies the DC / DC converter 68. If it is determined that there is a request for updating the software of the MG assembly 32, there is no need to start the engine 22, so the MG relay 35 is turned on (step S120), and startup processing of the MG assembly 32 including the MGECU 34 is performed, and this process ends. Thereafter, software updates are performed on the started MGECU 34 and the like.

[0023] If it is determined in step S100 that there is no request for updating the software of the MG assembly 32, the process waits for the starter motor 25 to complete cranking the engine 22 (step S110), then turns on the MG relay 35 (step S120), performs startup processing for the MG assembly 32 including the MGECU 34, and ends this processing. Thereafter, the main ECU 70 transmits a control signal (torque command, etc.) to the MGECU 34 to drive the motor 30, and the MGECU 34 receives the signal and controls the drive of the motor 30.

[0024] In the hybrid vehicle 20 of the embodiment described above, when the ignition switch 80 is turned on, the MG relay 35 is turned on to perform the startup process for the MG assembly 32 including the MGECU 34 after waiting for the starter motor 25 to complete cranking of the engine 22. This makes it possible to avoid an abnormality that may occur due to a voltage drop when the MG relay 35 is turned on to start the MG assembly 32 while the voltage of the low-voltage battery 67 is dropping while the engine 22 is being cranked by the starter motor 25. As a result, the startup process for the MG assembly 32 can be more reliably performed when the ignition switch 80 is turned on.

[0025] In the hybrid vehicle 20 of the embodiment, the MG relay 35 is turned on and off by the DC / DC converter 68, but the MG relay 35 may be turned on and off by the main ECU 70. In this case, the main ECU 70 may perform the ignition-on process.

[0026] In the hybrid vehicle 20 of the embodiment, when the ignition switch 80 is turned on, it is determined whether or not there is a request to update the software of the MG assembly 32. However, it is also possible to wait until cranking of the engine 22 by the starter motor 25 is completed without determining whether or not there is a request to update the software of the MG assembly 32, and then turn on the MG relay 35.

[0027] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problems" section will be described below. In the embodiment, the engine 22 corresponds to the "engine," the high-voltage battery 60 corresponds to the "high-voltage battery," the low-voltage battery 67 corresponds to the "low-voltage battery," the motor 30 corresponds to the "electric motor," the starter motor 25 corresponds to the "starter motor," the DC / DC converter 68 corresponds to the "DC / DC converter," the MG relay 35 corresponds to the "electric motor relay," the MG assembly 32 corresponds to the "drive device," and the DC / DC converter 68 corresponds to the "control device."

[0028] The correspondence between the main elements of the embodiments and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, since the embodiments are examples for specifically explaining the mode for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the embodiments are merely specific examples of the invention described in the "Means for Solving the Problem" section.

[0029] Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and it goes without saying that the present invention can be embodied in various forms without departing from the spirit of the present invention. [Industrial Applicability]

[0030] The present invention can be used in the hybrid vehicle manufacturing industry and the like. [Explanation of symbols]

[0031] 20 hybrid vehicle, 22 engine, 23 crankshaft, 23b pulley, 24 engine ECU, 25 starter motor, 28 damper, 30 motor, 30b pulley, 31 belt, 32 drive unit, 32 MG assembly, 33 inverter, 34 motor electronic control unit (MGECU), 35 MG relay, 40 automatic transmission, 41 input shaft, 46a rotation 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 power line, 66 low-voltage power line, 67 low-voltage battery, 68 DC / DC converter, 70 main electronic control unit (main ECU), 80 ignition switch.

Claims

[Claim 1] The engine and A high voltage battery; A low voltage battery; an electric motor that inputs and outputs power to and from an output shaft of the engine while exchanging power with a high-voltage power line connected to the high-voltage battery; a starter motor that receives power from a low-voltage power line connected to the low-voltage battery and cranks the engine; a DC / DC converter connected to the high-voltage power line and the low-voltage power line, for exchanging power between the high-voltage power line and the low-voltage power line while converting voltage; a drive device connected to the low-voltage side power line via a motor relay to drive the motor; a control device that turns on and off the electric motor relay; A hybrid vehicle comprising: the control device turns on the electric motor relay after confirming that cranking of the engine by the starter motor has been completed when an ignition switch is turned on; A hybrid vehicle characterized by

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