Hybrid vehicle

Abstract

To quickly reduce a driving force for traveling, when passing over a step or traveling an uphill slope is finished in automatic parking control.SOLUTION: When a hybrid vehicle is instructed to perform automatic parking and detects a step or an uphill slope during execution of a first automatic parking control for causing the vehicle to travel to a parking space by using power from a motor due to stopping of an engine, the hybrid vehicle performs a second automatic parking control for causing the vehicle to travel by using power from the engine and the motor. When the hybrid vehicle finishes passing over the step or traveling the uphill slope, the hybrid vehicle separates a piston from a friction engagement plate and then resumes the first automatic parking control.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, a first clutch provided between the engine and the motor, a transmission connected to the drive wheels, and a second clutch provided between the motor and the transmission (see, for example, Patent Document 1). In this hybrid vehicle, during automatic parking control, the accuracy of driving control is ensured by prioritizing an electric driving mode in which the first clutch is released and the second clutch is constantly engaged to drive the vehicle using only the motor as a driving power source. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-17504 Summary of the Invention [Problem to be solved by the invention]

[0004] In such hybrid vehicles, automatic parking control requires the vehicle to run with a large driving force (driving force output to the drive wheels) for going over a bump or climbing a slope, and when the vehicle finishes going over the bump or climbing a slope, the driving force must be reduced quickly. However, drag of the second clutch can cause the driving force to be transmitted to the drive wheels, which can take time to reduce the driving force. The hybrid vehicle disclosed herein has a primary objective of reducing the driving force quickly when the vehicle finishes going over a bump or climbing a slope during automatic parking control. [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, a transmission connected to drive wheels, a motor provided between the engine and the transmission, a clutch provided between the engine and the transmission in series with the motor and having a piston and a friction engagement plate, and a control device, wherein when an automatic parking command is received and a step or an uphill slope is detected during execution of a first automatic parking control that stops the engine and drives the vehicle to a parking space using power from the motor, the control device executes a second automatic parking control that uses power from the engine and the motor to drive the vehicle with a driving force for travel that is greater than that of the first automatic parking control, and when the vehicle has finished going over the step or climbing the slope, the control device separates the piston from the friction engagement plate and then resumes the first automatic parking control.

[0006] In the hybrid vehicle disclosed herein, by separating the piston from the friction engagement plate when the vehicle has finished going over a step or climbing a slope, the transmission of driving force (particularly driving force from the engine) to the drive wheels due to clutch drag can be suppressed, and the driving force for driving can be quickly reduced. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram of a hybrid vehicle 20 according to an embodiment. [Figure 2] 4 is a flowchart showing an example of a processing routine executed by the main ECU 38. [Figure 3] FIG. 10 is a schematic diagram of a hybrid vehicle 120 according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0008] A mode (embodiment) for carrying out the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic configuration 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 24, an inverter 25, a battery 26 (power storage device), a clutch K0, a clutch WSC, a transmission 28, a drive electronic control unit (hereinafter referred to as a "drive ECU") 30, a brake device 32, a brake electronic control unit (hereinafter referred to as a "brake ECU") 33, a steering device 34, a main electronic control unit (hereinafter referred to as a "main ECU") 38, a shift electronic control unit (hereinafter referred to as a "shift ECU") 50, a surroundings recognition electronic control unit (hereinafter referred to as a "surroundings recognition ECU") 55, and a navigation device 60.

[0009] The engine 22 is configured as an internal combustion engine that outputs power using fuel such as gasoline or diesel. The motor 24 is configured, for example, as a synchronous generator motor having a rotor (rotating shaft 24a) and a stator. The inverter 25 has a plurality of switching elements. The motor 24 is rotationally driven by switching the plurality of switching elements of the inverter 25. The battery 26 is configured, for example, as a lithium-ion secondary battery or a nickel-metal hydride secondary battery, and is connected to the inverter 25 via a power line. The clutch K0 is provided between the crankshaft 22a of the engine 22 and the rotating shaft 24a of the motor 24. The clutch WSC is provided between the rotating shaft 24a of the motor 24 and the input shaft of the transmission 28. The clutch K0 and the clutch WSC are each configured as hydraulically driven friction clutches and have a hydraulic servo configured with a piston, a plurality of friction engagement plates (friction plates and separator plates), an engagement oil chamber to which hydraulic oil is supplied, and the like. Transmission 28 has an input shaft, an output shaft, multiple planetary gears, and multiple hydraulically driven friction engagement elements (clutches and brakes). The output shaft of transmission 28 is connected to drive wheels 36a, 36b via a differential gear 35. Transmission 28 establishes multiple forward and reverse gears by engaging and disengaging the multiple friction engagement elements, connecting the input shaft and the output shaft (transmitting power between them) or disconnecting the input shaft and the output shaft.

[0010] The drive ECU 30 includes a microcomputer. The drive ECU 30 receives signals from various sensors. For example, the drive ECU 30 receives the crank angle θcr of the crankshaft 22a of the engine 22 from a crank position sensor, the rotational position θm of the rotor of the motor 24 from a rotational position sensor, the phase currents Iu, Iv, and Iw of each phase of the motor 24 from a current sensor, and the rotational speeds Ni and No of the input and output shafts of the transmission 28 from a rotational speed sensor. The drive ECU 30 performs various control functions, such as control of the engine 22, the inverter 25, the clutch K0, the clutch WSC, and the transmission 28. The drive ECU 30 calculates the rotational speed Ne of the engine 22 based on the crank angle θcr of the engine 22, and calculates the electrical angle θe and rotational speed Nm of the motor 24 based on the rotational position θm of the rotor of the motor 24. The drive ECU 30 communicates with the main ECU 38.

[0011] The brake device 32 is configured as a well-known hydraulically driven brake device and is configured to apply braking force resulting from the brake depression force applied by depressing the brake pedal 48 and braking force resulting from hydraulic pressure adjustment to the drive wheels 36a, 36b and the driven wheels 36c, 36d. The brake ECU 33 is equipped with a microcomputer. The brake ECU 33 controls the brake device 32, specifically, controls the braking force resulting from the brake depression force applied by the brake device 32 and braking force resulting from hydraulic pressure adjustment. The brake ECU 33 communicates with the main ECU 38. The steering device 34 is mechanically connected to the drive wheels 36a, 36b via a steering shaft and is equipped with a steering actuator. The steering device 34 steers the drive wheels 36a, 36b based on the steering operation by the driver, or steers the drive wheels 36a, 36b by driving the actuator based on a steering signal from the main ECU 38.

[0012] The main ECU 38 includes a microcomputer. The main ECU 38 receives signals from various sensors. For example, the main ECU 38 receives the voltage Vb of the battery 26 from a voltage sensor and the current Ib of the battery 26 from a current sensor. The main ECU 38 also receives an ignition signal IG from an ignition switch 40, a vehicle speed V from a vehicle speed sensor 41, wheel speeds Vwa-Vwd of the drive wheels 36a, 36b and the driven wheels 36c, 36d from a wheel speed sensor 42, and an acceleration α from an acceleration sensor 43. The main ECU 38 also receives a yaw rate Yr from a yaw rate sensor 44 and a road gradient θr from a gradient sensor 45. The main ECU 38 also receives the depression amount of the accelerator pedal 46 (accelerator pedal position AP) from an accelerator pedal position sensor 47 and the depression amount of the brake pedal 48 (brake pedal position BP) from a brake pedal position sensor 49.

[0013] The main ECU 38 performs various controls, such as control of the steering device 34, control of a display device 70 attached to the instrument panel, and control of a communication device 72. The main ECU 38 calculates the state of charge (SOC) of the battery 26 based on the integrated value of the current Ib of the battery 26. As described above, the main ECU 38 communicates with the drive ECU 30 and the brake ECU 33. The main ECU 38 also communicates with the shift ECU 50, the surroundings recognition ECU 55, and the navigation device 60.

[0014] The shift ECU 50 includes a microcomputer. The shift ECU 50 receives signals from various sensors. For example, the shift ECU 50 receives the operation position (shift operation position signal) of the shift lever 51 from a shift position sensor 52. The shift ECU 50 communicates with the main ECU 38 and the surroundings recognition ECU 55. For example, the shift ECU 50 sets a shift position SP based on the shift operation position signal from the shift position sensor 52 and a surroundings recognition signal (described later) from the surroundings recognition ECU 55, and transmits the set shift position SP to the main ECU 38. Examples of the shift operation position and the shift position SP include a parking position (P position), a neutral position (N position), a drive position (D position), and a reverse position (R position).

[0015] The periphery recognition ECU 55 includes a microcomputer. The periphery recognition ECU 55 receives various signals as input. For example, the periphery recognition ECU 55 receives a periphery recognition signal indicating information about the vehicle and its surroundings from the periphery recognition device 56 (e.g., inter-vehicle distances D1 and D2 between the vehicle and other vehicles ahead and behind the vehicle, and the vehicle's position in the lane on the road surface), and an automatic parking switch signal from the automatic parking switch 57. Examples of components of the periphery recognition device 56 include a camera, millimeter-wave radar, quasi-millimeter-wave radar, infrared laser radar, and sonar. As described above, the periphery recognition ECU 55 communicates with the main ECU 38 and the shift ECU 50.

[0016] The navigation device 60 includes a main body 61 with a built-in control unit, a GPS antenna 62, and a display 63. The control unit of the main body 61 includes a microcomputer, a storage medium (e.g., a hard disk or SSD), an input / output port, and a communication port. The storage medium stores map information and the like. The map information includes service information (e.g., tourist information, parking lots, etc.) and road information for each driving section (e.g., between traffic lights and between intersections). The road information includes distance information, road width information, and gradient information. The GPS antenna 62 receives information about the current location of the vehicle. The display 63 is configured as a touch panel display, and displays various information such as map information, information about the current location of the vehicle, and information about the planned driving route to the destination, and allows the user to input various instructions. When the user operates the display 63 to set a destination, the main body 61 of the navigation device 60 sets a planned driving route from the current location of the vehicle to the destination based on the map information, the current location of the vehicle, and the destination, and displays the set planned driving route on the display 63 to provide route guidance.

[0017] The hybrid vehicle 20 of this embodiment runs in a hybrid driving (HV driving) mode or an electric driving (EV driving) mode. The HV driving mode is a mode in which the clutch K0 and the clutch WSC are engaged (including a slip engagement state) and the vehicle runs with the engine 22 operating. The EV driving mode is a mode in which the clutch K0 is released and the clutch WSC is engaged, and the vehicle runs without the engine 22 operating.

[0018] Next, the operation of the hybrid vehicle 20 of this embodiment, particularly the operation when an automatic parking command is issued, will be described. FIG. 2 is a flowchart showing an example of a processing routine executed by the main ECU 38. This routine is executed repeatedly when an automatic parking command is issued until the vehicle is parked in the target parking space. Note that the automatic parking command is issued, for example, by the driver turning on the automatic parking switch 57 and operating the display 63 of the navigation device 60 to set the target parking space.

[0019] 2, the main ECU 38 first determines whether a step or an uphill slope has been detected (step S100). If it determines that neither a step nor an uphill slope has been detected, the main ECU 38 executes first automatic parking control (step S150) and terminates the routine. Here, the first automatic parking control sets a target route for parking the vehicle in a target parking space through cooperative control of the main ECU 38, drive ECU 30, brake ECU 33, shift ECU 50, etc., and controls the shift position SP, engine 22, motor 24 (inverter 25), clutch K0, clutch WSC, brake device 32, and steering device 34 so that the vehicle travels along the target route to the target parking space in EV driving mode. The determination process of step S100 can be performed using, for example, the vehicle speed V during the first automatic parking control and the driving power of the engine 22 and motor 24.

[0020] If a step or an uphill slope is detected in step S100, the second automatic parking control is executed (step S110), and it is determined whether the step or uphill travel has ended (step S120). If it is determined that the step or uphill travel has not ended, the process returns to step S110. Here, the second automatic parking control controls the shift position SP, the engine 22, the motor 24 (inverter 25), the clutch K0, the clutch WSC, the brake device 32, and the steering device 34 through cooperative control of the main ECU 38, the drive ECU 30, the brake ECU 33, the shift ECU 50, and the like, so that the vehicle travels in HV travel mode along the target route described above. At this time, the clutch WSC is in a fully engaged state or a slip-engaged state. In addition, in this embodiment, the traveling drive force (the drive force output to the drive wheels 36a, 36b) is gradually increased until the step or uphill travel ends. The process of step S120 can be performed, for example, in the same manner as the process of step S100.

[0021] When it is determined in step S120 that the vehicle has finished traveling over a step or uphill, the drive force of the engine 22 and the motor 24 is reduced and the clutch WSC is stroked back (step S130), and it is determined whether the driving force for traveling has decreased to or below a predetermined value (step S140). The stroke back of the clutch WSC is a process in which the hydraulic servo reduces the hydraulic pressure in the engagement oil chamber to separate the piston from the friction engagement plate. The determination process in step S140 can be performed, for example, based on the drive force of the engine 22 and the motor 24 and the hydraulic pressure (transmission torque) of the clutch WSC. Since the second automatic parking control increases the driving force for traveling, it is necessary to quickly reduce the driving force after traveling over a step. When the piston of the clutch WSC is in contact with the friction engagement plate, the transmission torque of the clutch WSC can be quickly adjusted by adjusting the hydraulic pressure in the engagement oil chamber. However, it may take time for the driving force for traveling to decrease due to clutch WSC drag. In contrast, in this embodiment, by separating the piston from the friction engagement plate, the drag of the clutch WSC is sufficiently reduced and the driving force for traveling can be quickly reduced. This makes it possible to easily control the vehicle using the brake device 32. If it is determined in step S140 that the driving force for traveling has decreased to or below the predetermined driving force, the first automatic parking control is resumed (step S150), and this routine ends.

[0022] In the hybrid vehicle 20 of the embodiment described above, when a step or an uphill slope is detected while the first automatic parking control is being executed, the second automatic parking control is executed, and when the vehicle has finished going over the step or climbing the slope, the clutch WSC separates the piston from the friction engagement plate, and then the first automatic parking control is resumed. This allows the driving force for traveling caused by the drag of the clutch WSC to be quickly reduced after the vehicle has finished going over the step.

[0023] In the above-described embodiment, when a step or slope is detected while the first automatic parking control is being executed and the second automatic parking control is being executed and the vehicle finishes going over the step or traveling uphill, instead of using the clutch WSC to move the piston away from the friction engagement plate, the clutch K0 may be used to move the piston away from the friction engagement plate.

[0024] In the above-described embodiment, a torque converter 27 may be provided instead of the clutch WSC of the hybrid vehicle 20, as shown in a modified hybrid vehicle 120 in Fig. 3. In this case, when a step or an uphill slope is detected while the first automatic parking control is being executed and the second automatic parking control is being executed and the vehicle has finished going over the step or traveling uphill, the clutch K0 can be used to separate the piston from the friction engagement plate.

[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, 24 Motor, 28 Transmission, 30 Drive ECU, 32 Brake device, 33 Brake ECU, 38 Main ECU, 50 Shift ECU, 55 Surrounding recognition ECU, K0, WSC clutch.

Claims

[Claim 1] A hybrid vehicle including an engine, a transmission connected to drive wheels, a motor provided between the engine and the transmission, a clutch provided in series with the motor between the engine and the transmission and having a piston and a friction engagement plate, and a control device, When an automatic parking command is received and a step or an uphill slope is detected during execution of a first automatic parking control in which the engine is stopped and the vehicle is driven to a parking space using power from the motor, the control device executes a second automatic parking control in which the vehicle is driven with a larger driving force for driving than that of the first automatic parking control using power from the engine and the motor, and when the vehicle has finished driving over the step or uphill slope, the control device separates the piston from the friction engagement plate and then resumes the first automatic parking control. Hybrid car.

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