Hybrid vehicle

Abstract

To suppress occurrence of shift operation malfunction that may occur when an abnormality occurs in a power conversion device that supplies power from a high-voltage battery to an auxiliary battery.SOLUTION: In a state that an abnormality has occurred in a power conversion device configured to reduce power of a high-voltage power line and to supply the reduced power to a low-voltage power line, when starting an engine using a starter motor that receives the power supplied from the low-voltage power line, the hybrid vehicle masks shifting operation until the engine starting is complete.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] A conventional hybrid vehicle of this type is proposed to execute a first fail-safe control associated with the cause of the restriction on the power supply from the high-voltage battery to the auxiliary battery when the power supply from the high-voltage battery to the auxiliary battery is restricted (see, for example, Patent Document 1). In this hybrid vehicle, a second fail-safe control associated with the execution status of the first fail-safe control is also executed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-045489 Summary of the Invention [Problem to be solved by the invention]

[0004] In such hybrid vehicles, if an abnormality occurs in the power conversion device that supplies power from the high-voltage battery to the auxiliary battery, the engine is started using the starter motor. In this case, a voltage drop occurs in the low-voltage system, which can cause malfunctions in shift operations in vehicles that use a shift-by-wire system.

[0005] The hybrid vehicle of the present disclosure has a primary object to prevent malfunction of shifting operations that may occur when an abnormality occurs in a power conversion device that supplies power from a high-voltage battery to an auxiliary battery. [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 disclosed herein is a hybrid vehicle including an engine, an electric motor detachably attached to an output shaft of the engine, a high-voltage battery connected via a high-voltage power line to an inverter that drives the electric motor, a low-voltage battery connected to a low-voltage power line, a power conversion device connected to the high-voltage power line and the low-voltage power line and that reduces the power of the high-voltage power line and supplies it to the low-voltage power line, a starter motor that receives power from the low-voltage power line to start the engine, and a control device that controls the engine, the electric motor, the power conversion device, and the starter motor and performs shift operations by inputting detection signals from a sensor that detects a shift position, wherein the control device is characterized in that when starting the engine using the starter motor when an abnormality has occurred in the power conversion device, the control device masks the shift operation until the engine start is complete.

[0008] In the hybrid vehicle disclosed herein, if an abnormality occurs in a power conversion device connected to a high-voltage power line connected to a high-voltage battery and a low-voltage power line connected to a low-voltage battery, which reduces power from the high-voltage power line and supplies it to the low-voltage power line, the engine may be started using a starter motor supplied with power from the low-voltage power line. In this case, shifting operations are masked until engine starting is complete. This prevents shifting operations from malfunctioning even if a voltage drop occurs in the low-voltage system due to starting the engine using the starter motor when an abnormality occurs in the power conversion device that supplies power from the high-voltage battery to the auxiliary battery. [Brief explanation 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 disclosure. [Figure 2] 4 is a flowchart showing an example of an engine start process executed by an HVECU 70 when a converter malfunctions. DETAILED DESCRIPTION OF THE INVENTION

[0010] Next, an embodiment for carrying out the present disclosure will be described. Fig. 1 is a diagram showing an outline of the configuration of a hybrid vehicle 20 as one embodiment of the present disclosure. As shown in the figure, the hybrid vehicle 20 of the embodiment includes an engine 22, a motor 30, an inverter 32, a clutch K0, an automatic transmission 40, a high-voltage battery 60, a low-voltage battery 62, a DC / DC converter 64, and a hybrid electronic control unit (hereinafter referred to as "HVECU") 70.

[0011] The engine 22 is configured as an internal combustion engine that outputs power using fuel such as gasoline or diesel fuel from a fuel tank. A crankshaft 23 of the engine 22 is connected to a rotating shaft 31 (rotor) of a motor 30 via a clutch K0. The operation of the engine 22 is controlled by an engine electronic control unit (hereinafter referred to as "engine ECU") 24.

[0012] The engine ECU 24 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports (not shown). Signals from various sensors required for controlling the operation of the engine 22 are input to the engine ECU 24 via an input port. Examples of signals input to the engine ECU 24 include a crank angle θcr from a crank position sensor 23a that detects the rotational position of the crankshaft 23 of the engine 22 and a coolant temperature Tw from a water temperature sensor (not shown) that detects the temperature of the coolant for the engine 22. Various control signals for controlling the operation of the engine 22 are output from the engine ECU 24 via an output port. The engine ECU 24 is connected to the HVECU 70 via a communication port. The engine ECU 24 calculates the rotation speed Ne of the engine 22 based on the crank angle θcr of the crankshaft 23 from the crank position sensor 23a.

[0013] A starter motor 25 for cranking the engine 22 and an alternator 26 for generating electricity using power from the engine 22 are connected to the crankshaft 23 of the engine 22. The starter 25 and the alternator 26 are connected to a low-voltage power line 63 together with a low-voltage battery 62, and are controlled by the HVECU 70.

[0014] The motor 30 is configured as a synchronous generator motor and has a rotor with a permanent magnet embedded in the rotor core and a stator with a three-phase coil wound around the stator core. A rotating shaft 31 to which the rotor of the motor 30 is fixed is connected to the crankshaft 23 of the engine 22 via a clutch K0 and to an input shaft 41 of an automatic transmission 45. 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 a motor electronic control unit (hereinafter referred to as "motor ECU") 34 controlling the switching of multiple switching elements of the inverter 32.

[0015] The motor ECU 34 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports (not shown). Signals from various sensors are input to the motor ECU 34 via the input port. Examples of signals input to the motor ECU 34 include a rotational position θm from a rotational position sensor 30a that detects the rotational position of the rotor (rotating shaft 31) of the motor 30, and phase currents Iu and Iv from current sensors that detect the phase currents of each phase of the motor 30. The motor ECU 34 outputs control signals to the inverter 32 via the output port. The motor ECU 34 is connected to the HVECU 70 via the communication port. The motor ECU 34 calculates the rotational speed Nm of the motor 30 based on the rotational position θm of the rotor (rotating shaft 31) of the motor 30 from the rotational position sensor 30a.

[0016] The clutch K0 is configured as, for example, a hydraulically driven friction clutch, and is controlled by the HVECU 70 to connect and disconnect the crankshaft 23 of the engine 22 and the rotary shaft 31 of the motor 30.

[0017] The automatic transmission 40 includes a torque converter 43 and a six-speed automatic transmission 45. The torque converter 43 is configured as a typical fluid power transmission device and amplifies the torque of the input shaft 41 connected to the rotary shaft 31 of the motor 30 and transmits it to a transmission input shaft 44, which is the input shaft of the automatic transmission 45, or transmits the torque directly without amplifying it. The automatic transmission 45 includes the transmission input shaft 44, an output shaft 42 connected to drive wheels 49 via a differential gear 48, multiple planetary gears, multiple hydraulically driven friction engagement elements (clutches, brakes), and a parking lock mechanism 46. The automatic transmission 45 establishes forward gears (first through sixth gears) and reverse gears by engaging and disengaging the multiple friction engagement elements, and transmits power between the transmission input shaft 44 and the output shaft 42. A hydraulic control device (not shown) adjusts the hydraulic pressure of hydraulic oil from a mechanical oil pump or an electric oil pump and supplies it to the clutch K0 and the automatic transmission 45. The parking lock mechanism 46 operates to lock the output shaft 42 so that it cannot rotate when the shift position SP is operated to the parking position (P position).

[0018] High-voltage battery 60 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery with a rated voltage of several hundred volts, and is connected to high-voltage power line 61 together with inverter 32. Low-voltage battery 62 is configured as, for example, a lead-acid battery with a rated voltage of about 12 V or 14 V, and is connected to low-voltage power line 63 together with starter motor 25 and alternator 26. DC / DC converter 64 is connected to high-voltage power line 61 and low-voltage power line 63. DC / DC converter 64 supplies power from high-voltage power line 61 to low-voltage power line 63 while stepping down the voltage.

[0019] The HVECU 70 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports (not shown). Signals from various sensors are input to the HVECU 70 via the input ports. Examples of signals input to the HVECU 70 include the rotation speed Nin from a rotation speed sensor 41a attached to the input shaft 41 of the automatic transmission 40, the rotation speed Nmi from a rotation speed sensor 44a attached to the transmission input shaft 44 of the automatic transmission 40, and the rotation speed Nout from a rotation speed sensor 42a attached to the output shaft 42 of the automatic transmission 40. Other examples of signals input to the HVECU 70 include the voltage Vbh of the high-voltage battery 60 from a voltage sensor attached between the terminals of the high-voltage battery 60, the current Ibh of the high-voltage battery 60 from a current sensor attached to the output terminal of the high-voltage battery 60, and the voltage Vbl from a voltage sensor attached between the terminals of the low-voltage battery 62. Other examples include an ignition signal from an ignition switch 80, an accelerator opening Acc from an accelerator pedal position sensor 84 that detects the depression amount of an accelerator pedal 83, a brake pedal position BP from a brake pedal position sensor 86 that detects the depression amount of a brake pedal 85, and a vehicle speed V from a vehicle speed sensor 87. The HVECU 70 receives a shift position SP from a shift position sensor 82 that detects the operating position of a shift lever 81 from a shift electronic control unit (hereinafter referred to as "shift ECU") 72 via a communication port. In other words, the hybrid vehicle of this embodiment employs a so-called shift-by-wire system.

[0020] Various control signals are output from the HVECU 70 via an output port. Examples of signals output from the HVECU 70 include a control signal to the starter motor 25 and a control signal to the alternator 26. Other examples include control signals to the clutch K0 and the automatic transmission 40 (hydraulic control device), a drive control signal to the parking lock mechanism 46, and a control signal to the DC / DC converter 64. The HVECU 70 is connected to the engine ECU 24 and the motor ECU 34 via communication ports. The HVECU 70 calculates the rotation speed ratio Gt of the automatic transmission 40 by dividing the rotation speed Nin of the input shaft 41 of the automatic transmission 40 from the rotation speed sensor 41a by the rotation speed Nout of the output shaft 42 of the automatic transmission 40 from the rotation speed sensor 42a.

[0021] In the hybrid vehicle 20 of this embodiment configured as described above, the engine 22, the clutch K0, the motor 30, and the automatic transmission 40 are controlled by cooperative control between the HVECU 70, the engine ECU 24, and the motor ECU 34 to travel in a hybrid driving mode (HV driving mode) or an electric driving mode (EV driving mode). Here, the HV driving mode is a mode in which the clutch K0 is engaged and the vehicle travels using the power of the engine 22, and the EV driving mode is a mode in which the clutch K0 is disengaged and the vehicle travels without using the power of the engine 22.

[0022] Next, a description will be given of the operation of the hybrid vehicle 20 of this embodiment configured as described above, particularly the operation when starting the engine 22 when an abnormality occurs in the DC / DC converter 64. Fig. 2 is a flowchart showing an example of an engine start process when a converter abnormality occurs, which is executed by the HVECU 70.

[0023] When the engine start process during converter abnormality is executed, the HVECU 70 first determines whether or not an abnormality has occurred in the DC / DC converter 64 (step S100). In this embodiment, an abnormality in the DC / DC converter 64 is detected by an abnormality detection process (not shown), and if an abnormality is detected in the DC / DC converter 64, the abnormality determination flag Fdc is set to the value 1. Therefore, the process in step S100 determines whether or not the abnormality determination flag Fdc is set to the value 1. If it is determined that no abnormality has occurred in the DC / DC converter 64 (the abnormality determination flag Fdc is set to the value 0), this process is not targeted, and therefore this process is terminated.

[0024] If it is determined in step S100 that an abnormality has occurred in the DC / DC converter 64, it is determined whether the engine 22 is stopped (step S110). If it is determined that the engine 22 is operating, starting the engine 22 is not necessary and the process is not subject to this process, so the process is terminated.

[0025] If it is determined in step S110 that the engine 22 is stopped, preparations for starting the engine 22 are initiated (step S120), and shift operations are masked (step S130). Preparations for starting the engine 22 include the start of cranking by the starter motor 25. Shift operations are masked by masking (not accepting) signals from the shift ECU 72.

[0026] Then, the process waits for the start of the engine 22 to be completed while the shift operation is masked (step S140), and then the masking of the shift operation is released (step S150), and this process ends. The completion of the start of the engine 22 can be determined, for example, when the engine 22 has fully exploded and its rotation speed has reached the idle rotation speed.

[0027] In the hybrid vehicle 20 of the embodiment described above, when starting the engine 22 while an abnormality has occurred in the DC / DC converter 64, the shift operation is masked until the start of the engine 22 is completed. This prevents a shift operation malfunction even if a voltage drop occurs in the low voltage system due to starting the engine 22 using the starter motor 25 when an abnormality has occurred in the DC / DC converter 64.

[0028] 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 motor 30 corresponds to the "electric motor," the high-voltage power line 61 corresponds to the "high-voltage power line," the high-voltage battery 60 corresponds to the "high-voltage battery," the low-voltage power line 63 corresponds to the "low-voltage power line," the low-voltage battery 62 corresponds to the "low-voltage battery," the DC / DC converter 64 corresponds to the "power conversion device," the starter motor 25 corresponds to the "starter motor," and the HVECU 70, the engine ECU 24, and the motor ECU 34 correspond to the "controller."

[0029] 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.

[0030] The present disclosure has been described above using embodiments, but the present disclosure is not limited to these embodiments and can, of course, be embodied in various forms within the scope of the gist of the present disclosure. [Industrial Applicability]

[0031] The present disclosure is applicable to the hybrid vehicle manufacturing industry and the like. [Explanation of symbols]

[0032] 20 Hybrid vehicle, 22 Engine, 25 Starter motor, 26 Alternator, 30 Motor, 32 Inverter, 40 Automatic transmission, 48 Differential gear, 49 Drive wheels, 60 High voltage battery, 61 High voltage side power line, 62 Low voltage battery, 63 Low voltage side power line, 64 DC / DC converter, 70 HVECU, 72 Shift ECU, 81 Shift lever, 82 Shift position sensor.

Claims

[Claim 1] a high-voltage battery connected to an inverter that drives the electric motor via a high-voltage power line; a low-voltage battery connected to a low-voltage power line; a power conversion device connected to the high-voltage power line and the low-voltage power line, for reducing the power of the high-voltage power line and supplying the reduced power to the low-voltage power line; a starter motor that receives power from the low-voltage power line to start the engine; and a control device that controls the engine, the electric motor, the power conversion device, and the starter motor, and that performs a shift operation by inputting a detection signal from a sensor that detects a shift position, a control device that, when starting the engine using the starter motor while an abnormality is occurring in the power conversion device, masks the shift operation until the engine start is completed.

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