Hybrid vehicle

Abstract

To suppress shortening of a cruisable distance of a vehicle when a low-speed stage abnormality occurs.SOLUTION: When a low-speed stage abnormality occurs in which a predetermined low-speed stage of a transmission cannot be formed, a hybrid vehicle performs evacuation control of prohibiting intermittent operation of an engine. At the time of the evacuation control, in a case of traveling at a vehicle speed equal to or greater than a vehicle speed threshold, the hybrid vehicle brings a first clutch and a second clutch into an engagement state, in a case of traveling at a vehicle speed less than the vehicle speed threshold, the hybrid vehicle brings the first clutch into a release state and the second clutch into the engagement state, and in a case of vehicle stop, the hybrid vehicle brings the first clutch into the engagement state and the second clutch into the release state.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Conventionally, a hybrid vehicle has been proposed that includes an engine and a motor, an electricity storage device that exchanges electric power with the motor, a transmission connected to drive wheels, a first clutch provided between the engine and the motor, and a second clutch provided between the motor and the drive wheels (see, for example, Patent Document 1). In this hybrid vehicle, when a low-speed gear abnormality occurs in the transmission that prevents a low-speed gear from being established and the vehicle speed is equal to or higher than a predetermined speed, an evacuation travel mode is entered in which the first clutch and the second clutch are engaged, a gear that can be established in the transmission is established, and evacuation travel is performed using power from the engine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-63156 Summary of the Invention [Problem to be solved by the invention]

[0004] In such hybrid vehicles, if the vehicle speed is low when a low-gear abnormality occurs, and the transmission is set to an available gear and the second clutch is placed in a slip-engaged state to perform evacuation driving using power from the engine (and, if necessary, the motor), there is a concern that heat will be generated due to differential rotation of the second clutch. To address this issue, it is conceivable to stop the engine, release the first clutch, and fully engage the second clutch to perform evacuation driving using only power from the motor. However, when the vehicle speed reaches a predetermined speed or higher, the engine must be started by cranking the engine using the motor, and the motor's power consumption may shorten the vehicle's cruising range. The hybrid vehicle disclosed herein primarily aims to prevent the vehicle's cruising range from being shortened when a low-gear abnormality occurs. [Means for solving the problem]

[0005] The hybrid vehicle of the present disclosure employs the following measures to achieve the above-mentioned primary object. The hybrid vehicle of the present disclosure is a hybrid vehicle including an engine and a motor, an electric storage device that exchanges electric power with the motor, a transmission connected to drive wheels, a first clutch provided between the engine and the motor, a second clutch provided between the motor and the drive wheels, and a control device, wherein the control device executes evacuation control that prohibits intermittent operation of the engine when a low-speed gear abnormality occurs that prevents the transmission from achieving a predetermined low speed gear, and during the evacuation control, when the vehicle speed is equal to or greater than a vehicle speed threshold, the first clutch and the second clutch are engaged, when the vehicle speed is less than the vehicle speed threshold, the first clutch is released and the second clutch is engaged, and when the vehicle is stopped, the first clutch is engaged and the second clutch is released.

[0006] In the hybrid vehicle disclosed herein, by performing the above-described control, when the vehicle speed rises from below the vehicle speed threshold to above the vehicle speed threshold, the first clutch is switched from a released state to an engaged state while the engine continues to operate, thereby reducing the power consumption of the motor compared to a system in which the engine is started by cranking the engine using the motor. Furthermore, when the vehicle is stopped, power from the engine can be used by the motor to generate electricity and charge the battery. As a result, a reduction in the vehicle's cruising range when a low-speed abnormality occurs can be prevented. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram of a hybrid vehicle 20 according to an embodiment. [Figure 2] 10 is a flowchart illustrating an example of a processing routine. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic diagram of a hybrid vehicle 20 according to an embodiment of the present disclosure. As shown in the figure, the hybrid vehicle 20 according to the embodiment includes an engine 22, a motor 30, an inverter 32, a battery 34 (electricity storage device), a clutch K0, a clutch WSC, a transmission 40, and an electronic control unit 50 (control device).

[0009] The engine 22 is an internal combustion engine that uses fuel such as gasoline or diesel to output power, and includes a throttle valve, intake valves, exhaust valves, fuel injection valves, spark plugs, etc. The crankshaft 23 of the engine 22 is connected to a rotating shaft 31 of a motor 30 via a clutch K0. The motor 30 is configured as a synchronous generator motor, and includes a rotor fixed to the rotating shaft 31 and having a permanent magnet embedded therein, and a stator around which a three-phase coil is wound. The rotating shaft 31 of the motor 30 is connected to an input shaft 41 of a transmission 40 via a clutch WSC. The inverter 32 includes multiple switching elements. The motor 30 is rotationally driven by switching the multiple switching elements of the inverter 32. The battery 34 is configured as a lithium-ion secondary battery or a nickel-metal hydride secondary battery, and is connected to the inverter 32 via a power line.

[0010] The clutch K0 connects and disconnects the crankshaft 23 of the engine 22 to the rotating shaft 31 to which the rotor of the motor 30 is fixed. The clutch WSC connects and disconnects the rotating shaft 31 to which the rotor of the motor 30 is fixed to the input shaft 41 of the transmission 40. The clutch K0 and the clutch WSC are each configured as hydraulically driven friction clutches and have hydraulic servos composed of pistons, multiple friction engagement plates (friction plates and separator plates), and an oil chamber to which hydraulic oil is supplied. The clutch K0 and the clutch WSC are driven by hydraulic pressure supplied from a hydraulic control device 36. The transmission 40 is configured as an automatic transmission with 4 to 10 speeds and has an input shaft 41, an output shaft 42, multiple planetary gear mechanisms, and multiple hydraulically driven friction engagement elements (clutches and brakes). The output shaft 42 is connected to the drive wheels DWa and DWb via a differential gear DF. Each of the plurality of friction engagement elements has a hydraulic servo configured with a piston, a plurality of friction engagement plates (friction plates and separator plates), an oil chamber to which hydraulic oil is supplied, etc. The plurality of friction engagement elements are driven by hydraulic pressure supplied from a hydraulic control device 44. By putting the plurality of friction engagement elements into an engaged state or a disengaged state, the transmission 40 forms a plurality of forward speeds and reverse speeds and connects the input shaft 41 and the output shaft 42 (transmits power between them) or disconnects the input shaft 41 and the output shaft 42.

[0011] Each of the hydraulic control devices 36, 44 includes a valve body having a plurality of oil passages formed therein, a plurality of regulator valves, a plurality of linear solenoid valves, etc. The hydraulic control device 36 adjusts the pressure of hydraulic oil (hydraulic pressure) from the electric oil pump and supplies it to the clutch K0 and the clutch WSC. The hydraulic control device 44 adjusts the pressure of hydraulic oil (hydraulic pressure) from the electric oil pump and supplies it to desired friction engagement elements of the transmission 40. Note that the clutch K0, the clutch WSC, and the plurality of friction engagement elements of the transmission 40 may be driven by a single hydraulic control device.

[0012] The electronic control unit 50 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. The electronic control unit 50 receives signals from various sensors. For example, the electronic control unit 50 receives the rotational position (crank angle θcr) of the crankshaft of the engine 22 from the crank position sensor 23a, the rotational position θm of the rotor (rotating shaft 31) of the motor 30 from a rotational position sensor, and the phase currents Iu, Iv, and Iw of each phase of the motor 30 from a current sensor. The electronic control unit 50 also receives the voltage Vb and current Ib of the battery 34 from a voltage sensor and a current sensor, and the rotational speeds Ni and No of the input shaft 41 and output shaft 42 of the transmission 40 from two rotational speed sensors. The electronic control unit 50 also receives as input an ignition signal from an ignition switch 60, the operating position of the shift lever 61 (shift position SP) from a shift position sensor 62, the amount of depression of the accelerator pedal 63 (accelerator opening Acc) from an accelerator pedal position sensor 64, the amount of depression of the brake pedal 65 (brake pedal position BP) from a brake pedal position sensor 66, and the vehicle speed V from a vehicle speed sensor 67.

[0013] The electronic control unit 50 outputs various control signals. For example, the electronic control unit 50 outputs a control signal to the engine 22, a control signal to the inverter 32, a control signal to the clutch K0 and the clutch WSC (hydraulic control device 36), and a control signal to the transmission 40 (hydraulic control device 44). The electronic control unit 50 calculates the rotation speed Ne of the engine 22 based on the crank angle θcr of the engine 22, calculates the electrical angle θe and rotation speed Nm of the motor 30 based on the rotation position θm of the rotor of the motor 30, and calculates the power storage percentage SOC of the battery 34 based on the integrated value of the current Ib of the battery 34.

[0014] The hybrid vehicle 20 of the embodiment runs using power from the engine 22 (and also power from the motor 30 as needed) with the clutch K0 and the clutch WSC in an engaged state, or runs using only power from the motor 30 without using power from the engine 22 with the clutch K0 in a released state and the clutch WSC in an engaged state. Here, the engaged state of the clutch K0 means a fully engaged state, and the engaged state of the clutch WSC includes not only a fully engaged state but also a slipping engaged state.

[0015] Next, the operation of the hybrid vehicle 20 of this embodiment will be described, particularly the operation when a low-speed abnormality occurs in which the transmission 40 cannot achieve a low speed (for example, first forward speed and second forward speed) due to an abnormality in the hydraulic control device 44 or the like. FIG. 2 is a flowchart showing an example of a processing routine executed by the electronic control unit 50. This routine is executed repeatedly when a low-speed abnormality occurs and the vehicle is not in ready-off mode. In this case, the transmission 40 is set to a gear that is not experiencing an abnormality. For example, when the transmission 40 is an eight-speed transmission and cannot achieve first forward speed and second forward speed, the transmission 40 is set to one of third forward speed to eighth forward speed based on the accelerator opening Acc and the vehicle speed V.

[0016] 2 is executed, the electronic control unit 70 first determines whether the engine 22 is stopped or running (step S100), and if it determines that the engine 22 is stopped, determines whether the engine 22 can be started (step S110). The engine 22 is started by cranking the engine 22 using the motor 30 while the clutch K0 is in an engaged state (slip-engaged state or fully engaged state), and by commencing fuel injection and ignition of the engine 22. The processing of step S110 is processing for determining whether the engine 22 can be started by cranking the engine 22 using the motor 30, based on the power storage percentage SOC of the battery 34 and the vehicle speed V.

[0017] If it is determined in step S110 that the engine 22 cannot be started, a first evacuation control is executed (step S120). In the first evacuation control, the clutch K0 is released and the clutch WSC is engaged, and the engine 22, the motor 30, the clutch K0, the clutch WSC, and the transmission 40 are controlled so that the vehicle travels using only the power from the motor 30, without using the power from the engine 22. Then, it is determined whether the power storage percentage SOC of the battery 34 is less than a threshold value Slo (step S200). Here, the threshold value Slo is a threshold value used to determine whether travel should be ended (ready-off should be performed). If it is determined that the power storage percentage SOC of the battery 34 is equal to or greater than the threshold value Slo, the routine is terminated without ready-off. On the other hand, if it is determined that the power storage percentage SOC of the battery 34 is less than the threshold value Slo, the ready-off is performed (step S210), and the routine is terminated.

[0018] If it is determined in step S110 that the engine 22 can be started, the engine 22 is cranked by the motor 30 to start the engine 22 (step S130), and evacuation control is set to prohibit intermittent operation of the engine 22 (continuous operation) (step S140). Also, if it is determined in step S100 that the engine 22 is operating, evacuation control is set to prohibit intermittent operation of the engine 22 (step S140).

[0019] Once the engine 22 intermittent-prohibiting evacuation control is set in this manner, it is determined whether the vehicle speed V is less than a threshold value Vref (step S150). Here, the threshold value Vref is a threshold value used to determine whether there is a concern about overheating of the clutch WSC if the second evacuation control is executed. In the second evacuation control, the engine 22, the motor 30, the clutch K0, the clutch WSC, and the transmission 40 are controlled so that the clutch K0 and the clutch WSC are engaged and the vehicle travels using power from the engine 22 (and also power from the motor 30, as needed). Because a low-speed abnormality has occurred, when the vehicle speed V is low, it is necessary to increase the slip of the clutch WSC, which tends to increase the amount of heat generated by the clutch WSC. The processing of step S150 takes this into consideration. If it is determined in step S150 that the vehicle speed V is equal to or greater than the threshold value Vref, it is determined that there is little concern about overheating of the clutch WSC even if the second evacuation control is executed, the second evacuation control is executed (step S170), and the process proceeds to step S200.

[0020] If it is determined in step S150 that the vehicle speed V is less than the threshold value Vref, it is determined that there is a risk of overheating of the clutch WSC if the second evacuation control is executed, and it is determined whether the vehicle is moving or stopped (step S160). This process can be performed based on the vehicle speed V. If it is determined in step S160 that the vehicle is moving, the third evacuation control is executed (step S180), and the process proceeds to step S200. In the third evacuation control, the clutch K0 is released and the clutch WSC is engaged, and the engine 22, the motor 30, the clutch K0, the clutch WSC, and the transmission 40 are controlled so that the engine 22 is operated and the vehicle travels using only power from the motor 30. If it is determined in step S160 that the vehicle is stopped, the fourth evacuation control is executed (step S190), and the process proceeds to step S200. In the fourth evacuation control, the clutch K0 is engaged and the clutch WSC is released, and the engine 22, the motor 30, the clutch K0, the clutch WSC, and the transmission 40 are controlled so that power from the engine 22 is used to generate electricity at the motor 30 and charge the battery 34.

[0021] In this manner, when a low-speed abnormality occurs, while the engine 22 continues to operate, the clutch K0 and the clutch WSC are engaged when the vehicle is traveling at a speed V equal to or greater than the threshold Vref. When the vehicle speed V is less than the threshold Vref, the clutch K0 is released and the clutch WSC is engaged. When the vehicle is stopped, the clutch K0 is engaged and the clutch WSC is released. As a result, when the vehicle speed V changes from less than the threshold Vref to equal to or greater than the threshold Vref, the clutch K0 is changed from the released state to the engaged state while the engine 22 continues to operate. This reduces the power consumption of the motor 30 compared to starting the engine 22 by cranking it using the motor 30. Furthermore, when the vehicle is stopped, power from the engine 22 can be used by the motor 30 to generate electricity and charge the battery 34. As a result, the battery 34 is prevented from being ready-off due to the power storage percentage SOC of the battery 34 falling below the threshold Slo, thereby preventing a reduction in the vehicle's cruising range.

[0022] In the hybrid vehicle 20 of the embodiment described above, when a low-speed abnormality occurs, while continuing to operate the engine 22, if the vehicle is traveling at a vehicle speed V equal to or greater than the threshold value Vref, the clutch K0 and the clutch WSC are engaged, if the vehicle is traveling at a vehicle speed V less than the threshold value Vref, the clutch K0 is released and the clutch WSC is engaged, and if the vehicle is stopped, the clutch K0 is engaged and the clutch WSC is released. This makes it possible to prevent the vehicle's cruising distance from becoming shorter.

[0023] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problem" section will be described below. In the embodiment, the engine 22 corresponds to the "engine," the motor 30 corresponds to the "motor," the battery 34 corresponds to the "battery," the transmission 40 corresponds to the "transmission," the clutch K0 corresponds to the "first clutch," the clutch WSC corresponds to the "second clutch," and the electronic control unit 50 corresponds to the "control device."

[0024] 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.

[0025] The above describes the forms for implementing the present disclosure using embodiments, but the present disclosure is not limited to these embodiments in any way, and it goes without saying that the present disclosure can be implemented in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0026] The present disclosure is applicable to the hybrid vehicle manufacturing industry and the like. [Explanation of symbols]

[0027] 20 hybrid vehicle, 22 engine, 23 crankshaft, 23a crank position sensor, 30 motor, 31 rotating shaft, 32 inverter, 34 battery, 36 hydraulic control device, 40 transmission, 41 input shaft, 42 output shaft, 44 hydraulic control device, 50 electronic control unit, 60 ignition switch, 61 shift lever, 62 shift position sensor, 63 accelerator pedal, 64 accelerator pedal position sensor, 65 brake pedal, 66 brake pedal position sensor, 67 vehicle speed sensor.

Claims

[Claim 1] A hybrid vehicle including an engine and a motor, an electric storage device that exchanges electric power with the motor, a transmission connected to drive wheels, a first clutch provided between the engine and the motor, a second clutch provided between the motor and the drive wheels, and a control device, When a low-speed abnormality occurs that prevents the transmission from achieving a predetermined low speed, the control device executes evacuation control that prohibits intermittent operation of the engine, and during the evacuation control, when the vehicle speed is equal to or greater than a vehicle speed threshold, the control device brings the first clutch and the second clutch into an engaged state, when the vehicle speed is less than the vehicle speed threshold, the control device brings the first clutch into a released state and the second clutch into an engaged state, and when the vehicle is stopped, the control device brings the first clutch into an engaged state and the second clutch into a released state. Hybrid car.

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