Vehicle

Abstract

To suppress a driver feeling a rattling shock in a differential gear at the time of acceleration of a vehicle in an automatic driving mode.SOLUTION: A vehicle includes: an engine; a torque converter connected to the engine and including a lock-up clutch; a transmission connected to the torque converter and connected to a drive wheel via a differential gear; and a control device. In this case, when the control device predicts an acceleration request of the vehicle in an automatic driving mode, the control device performs transition control of a lock-up clutch before rattling elimination control of the differential gear.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a vehicle.

Background Art

[0002] Conventionally, as this type of vehicle, there has been proposed one including an engine, a torque converter connected to the engine and having a lock-up clutch, and a transmission connected to the torque converter and connected to drive wheels via a differential gear (see, for example, Patent Document 1). In this vehicle, there are provided an automatic driving control unit that automatically controls at least the torque of the engine so as to travel in a predetermined target driving state without requiring an acceleration / deceleration operation, and a lock-up control unit that engages and disengages the lock-up clutch according to a predetermined lock-up condition. Then, the automatic driving control unit sets the target driving state so that the lock-up clutch is in an engaged state according to the lock-up condition.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a vehicle, during transient control of a lock-up clutch, the torque transmitted from the engine to a differential gear via the torque converter and the transmission is likely to fluctuate. Therefore, when performing backlash elimination control of the differential gear during acceleration of the vehicle, if this and the transient control of the lock-up clutch are performed in parallel, it is likely to cause a backlash shock in the differential gear. Particularly in the automatic driving mode, the driver is likely to feel such a shock. The vehicle of the present disclosure mainly aims to suppress the driver from feeling a backlash shock in the differential gear during acceleration of the vehicle in the automatic driving mode.

Means for Solving the Problem

[0005] The vehicle of the present disclosure has adopted the following means to achieve the above main purpose. The vehicle of the present disclosure includes an engine, a torque converter connected to the engine and having a lock-up clutch, a transmission connected to the torque converter and connected to drive wheels via a differential gear, and a control device. When the control device predicts an acceleration request of the vehicle in the automatic driving mode, the gist is to perform transient control of the lock-up clutch before backlash elimination control of the differential gear.

[0006] In the vehicle of the present disclosure, by the above control, when the vehicle accelerates thereafter in the automatic driving mode, it is possible to suppress the transient control of the lock-up clutch and the backlash elimination control of the differential gear from being parallel, and suppress the driver from feeling a rattle shock in the differential gear.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0008] Modes 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 of the embodiment includes an engine 22, a motor 30, an inverter 32, a clutch K0, a power transmission device 40, a brake device 50, a steering device 52, a navigation device 60, and an electronic control unit (hereinafter referred to as “ECU”) 70.

[0009] The engine 22 is configured as an internal combustion engine that outputs power using hydrocarbon-based fuels such as gasoline and diesel oil. The crankshaft 23 of the engine 22 is connected to the transmission shaft 38 via the clutch K0. The motor 30 is configured as, for example, a synchronous generator motor, and the rotor of the motor 30 is attached to the transmission shaft 38. The inverter 32 has a plurality of switching elements and is connected to the battery 34 via a power line. The motor 30 is rotationally driven by switching the plurality of switching elements of the inverter 32. The clutch K0 is configured as, for example, a hydraulically driven friction clutch and connects and disconnects the engine 22 and the transmission shaft 38.

[0010] The power transmission device 40 includes a torque converter 41 and an automatic transmission 44. The torque converter 43 is configured as a general fluid transmission device and has a lock-up clutch 42. The lock-up clutch 42 is configured as, for example, a hydraulically driven friction clutch and connects and disconnects the pump impeller connected to the transmission shaft 38 and the turbine runner connected to the input shaft 45 of the automatic transmission 44. Such a torque converter 41 transmits the power of the transmission shaft 38 to the input shaft 45 of the automatic transmission 44 with torque amplification or transmits it as it is without torque amplification. The automatic transmission 44 has an input shaft 45, an output shaft 46, at least one planetary gear mechanism, and a plurality of hydraulically driven friction engagement elements (clutches, brakes). The output shaft 46 is connected to the drive wheels 49a, 49b via a differential gear 48. The automatic transmission 44 forms a plurality of forward and reverse gears by engaging and disengaging the plurality of friction engagement elements and transmits power between the input shaft 45 and the output shaft 46.

[0011] The braking device 50 is configured as a well-known hydraulically driven braking device, and is configured to be able to apply braking force resulting from the braking pedal force caused by stepping on the brake pedal 85 and braking force resulting from hydraulic pressure adjustment to the driving wheels 49a, 49b and the driven wheels 49c, 49d. The steering device 52 has the steering wheel and the driving wheels 49a, 49b mechanically connected via a steering shaft, and includes a steering actuator. The steering device 52 steers the driving wheels 49a, 49b based on the driver's operation, and also steers the driving wheels 49a, 49b by driving the actuator based on a steering signal from the ECU 70.

[0012] The navigation device 60 includes a main body with a built-in control unit, a GPS antenna, and a display. The control unit of the main body has a microcomputer, a storage medium (such as a hard disk or SSD) storing map information, etc., an input / output port, and a communication port. The map information includes service information (such as tourism information and parking lots), road information for each driving section (such as between traffic lights and intersections), etc. The road information includes distance information, width information, number of lanes information, regional information (urban areas and suburbs), type information (general roads and highways), gradient information, legal speed, number of traffic lights, etc. The GPS antenna receives information regarding the current location of the vehicle. The display is configured as a touch panel type display, and can display various information such as map information, the current location of the vehicle, and the planned driving route to the destination, and allows the user to input various instructions. When the destination is set by the user operating the display, the main body of the navigation device sets the 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 to provide route guidance.

[0013] The ECU 70 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. The ECU 70 inputs signals from various sensors via the input ports. For example, the ECU 70 inputs signals related to the states of the engine 22, motor 30, battery 34, power transmission device 40, and brake device 50. Examples of these signals include the crank angle θcr of the crankshaft 23 of the engine 22 from the crank position sensor 23a, the rotational position θm of the rotor of the motor 30 from the rotational position sensor 30a, and the rotational speeds Nin and Nout of the input shaft 45 and output shaft 46 of the automatic transmission 44 from the rotational speed sensors 45a and 46a. The ECU 70 also inputs the ignition signal IG from the ignition switch 80, the shift position SP which is the operation position of the shift lever 81 from the shift position sensor 82, the accelerator pedal position AP which is the depression amount of the accelerator pedal 83 from the accelerator pedal position sensor 84, and the brake pedal position BP which is the depression amount of the brake pedal 85 from the brake pedal position sensor 86. The ECU 70 further inputs the vehicle speed V from the vehicle speed sensor 87, the wheel speeds Vwa to Vwd of the drive wheels 49a and 49b and the driven wheels 49c and 49d from the wheel speed sensors 88, the acceleration α from the acceleration sensor 89, and the yaw rate Yr from the yaw rate sensor 90. The ECU 70 also inputs a signal indicating information about the host vehicle and its surroundings from the surrounding recognition device 91 (for example, the inter-vehicle distances D1 and D2 between the host vehicle and other vehicles in front of and behind the host vehicle, and the driving position of the host vehicle in the lane of the road surface), and a mode signal Md from the automatic driving switch 92. Examples of the surrounding recognition device 91 include a camera, millimeter-wave radar, quasi-millimeter-wave radar, infrared laser radar, sonar, etc. The automatic driving switch 92 is a switch for switching between a manual driving mode in which the driver performs driving operations and an automatic driving mode in which the driver does not perform driving operations.

[0014] The ECU 70 outputs various control signals via the output ports. For example, the ECU 70 outputs control signals to the engine 22, the inverter 32, the clutch K0, the power transmission device 40 (the lock-up clutch 42 and the automatic transmission 44), the brake device 50, and the steering device 52. The ECU 70 calculates the engine speed Ne based on the crank angle θcr of the crankshaft 23 of the engine 22, or calculates the motor speed Nm of the motor 30 based on the rotational position θm of the rotor of the motor 22m. The ECU 70 communicates with the navigation device 60.

[0015] In the hybrid vehicle 20 of the embodiment configured in this way, it travels by switching between the manual driving mode (the automatic driving switch 92 is off) and the automatic driving mode (the automatic driving switch 92 is on). In the manual driving mode, the ECU 70 sets the required torque Td* for driving based on the accelerator pedal position AP, the brake pedal position BP, and the vehicle speed V, and controls the engine 22, the motor 30, the clutch K0, the power transmission device 40 (the lock-up clutch 42 and the automatic transmission 44), and the brake device 50 to travel according to the set required torque Td*. In the automatic driving mode, the ECU 70 sets the target vehicle speed V* based on the information from the navigation device 60 (for example, the planned route, the current location of the host vehicle, map information, etc.) and the information from the surrounding recognition device 91 (for example, information about the host vehicle and its surroundings), sets the required torque Td* so that the vehicle speed V becomes the target vehicle speed V*, and controls the engine 22, the motor 30, the clutch K0, the power transmission device 40, the brake device 50, and the steering device 52 to travel according to the required torque Td* along the planned route.

[0016] Next, the operation of the hybrid vehicle 20 of the embodiment will be described, particularly the transient control of the lock-up clutch 42 and the backlash elimination control of the differential gear 48. The transient control of the lock-up clutch 42 refers to the control when switching the lock-up clutch 42 from release to engagement or from engagement to release. The backlash elimination control of the differential gear 48 is to suppress the backlash shock of the differential gear 48 when the vehicle is accelerating. To this end, the torque output from the engine 22 side to the differential gear 48 via the power transmission device 40 is gently increased compared to after the backlash elimination of the differential gear 48, and the backlash elimination of the differential gear 48 is performed. FIG. 2 is a flowchart showing an example of a processing routine executed by the ECU 70.

[0017] When this routine is executed, the ECU 70 first determines whether it is in the manual operation mode or the automatic operation mode based on the mode signal Md (step S100). When it is determined that it is in the manual operation mode, it is determined whether an acceleration request for the vehicle is being made based on the accelerator pedal position AP or the like (step S110). When it is determined that no acceleration request for the vehicle is being made, the process returns to step S100. When it is determined that an acceleration request for the vehicle is being made, it is determined whether it is in the normal lock-up (L / UP) control mode (step S120). Here, the normal lock-up control mode, the predictive lock-up control mode and the shock suppression lock-up control mode described later are modes for performing transient control of the lock-up clutch 42 in each situation. When it is determined that it is in the normal lock-up control mode, the transient control of the lock-up clutch 42 is started (step S130), and the backlash elimination control of the differential gear 48 is started (step S260), and this routine ends. In this case, both are performed in parallel. When it is determined that it is not in the normal lock-up control mode, the backlash elimination control of the differential gear 48 is started without performing the transient control of the lock-up clutch 42 (step S260), and this routine ends.

[0018] When it is determined in step S100 that the vehicle is in the automatic driving mode, it is determined whether an acceleration request of the vehicle within a predetermined time (for example, about several seconds) is predicted (step S140). This determination process can be performed based on, for example, the acceleration of other vehicles around the host vehicle, road conditions (such as signals), and the like. When it is determined that an acceleration request of the vehicle within the predetermined time is predicted, it is determined whether it is in the predictive lock-up control mode (step S150). When it is determined that it is not in the predictive lock-up control mode, the process returns to step S100. When it is determined that it is in the predictive lock-up control mode, the transient control of the lock-up clutch 42 is started (step S160). Thereafter, after the transient control of the lock-up clutch 42 is terminated and waiting for the vehicle acceleration request to be made (steps S170, S180), the backlash elimination control of the differential gear 48 is started (step S260), and this routine is terminated. Thereby, it is possible to suppress the parallel execution of the transient control of the lock-up clutch 42 and the backlash elimination control of the differential gear 48. During the transient control of the lock-up clutch 42, the torque transmitted from the engine 22 side to the differential gear 48 via the power transmission device 40 is likely to fluctuate. Therefore, if the transient control of the lock-up clutch 42 and the backlash elimination control of the differential gear 48 are performed in parallel, a rattling shock is likely to occur in the differential gear 48. In the automatic driving mode, the driver is more likely to feel such a shock than in the manual driving mode. In the embodiment, by suppressing the parallel execution of both, it is possible to suppress the driver from feeling such a shock. Note that the transient control of the lock-up clutch 42 in the predictive lock-up control mode and the normal lock-up control mode may be the same as or different from each other.

[0019] When it is determined in step S140 that no vehicle acceleration request is predicted within a predetermined time, it is determined whether a vehicle acceleration request is currently being made (step S190). When it is determined that no vehicle acceleration request is being made, the process returns to step S100. When it is determined that a vehicle acceleration request is being made, it is determined whether a high response request for the vehicle is being made (step S200). This determination process can be performed based on, for example, the distance between the host vehicle and surrounding vehicles, the acceleration of the host vehicle, and the presence or absence of a vehicle speed instruction from the driver.

[0020] When it is determined in step S200 that a high response request for the vehicle is being made, it is determined whether it is in the normal lock-up control mode (step S210). When it is determined that it is in the normal lock-up control mode, the transient control of the lock-up clutch 42 is started (step S130), and the backlash elimination control of the differential gear 48 is started (step S260), and this routine ends. When it is determined that it is not in the normal lock-up control mode, the backlash elimination control of the differential gear 48 is started without performing the transient control of the lock-up clutch 42 (step S260), and this routine ends.

[0021] When it is determined in step S200 that the high response requirement of the vehicle is not being made, it is determined whether or not it is in the shock suppression lock-up control mode (step S230). When it is determined that it is in the shock suppression lock-up control mode, the transient control of the lock-up clutch 42 is started (step S240). After that, waiting for the transient control of the lock-up clutch 42 to end (steps S170, S180), the backlash elimination control of the differential gear 48 is started (step S260), and this routine ends. Also in this case, it is possible to suppress the parallel execution of the transient control of the lock-up clutch 42 and the backlash elimination control of the differential gear 48, and suppress the driver from feeling the backlash shock in the differential gear 48. Note that the transient control of the lock-up clutch 42 in the shock suppression lock-up control mode is performed so that the torque fluctuation output to the differential gear 48 is suppressed rather than the rapidity compared to the transient control of the lock-up clutch 42 in the normal lock-up control mode. When it is determined in step S230 that it is not in the shock suppression lock-up control mode, the backlash elimination control of the differential gear 48 is started without performing the transient control of the lock-up clutch 42 (step S260), and this routine ends.

[0022] In the hybrid vehicle 20 of the present embodiment described above, when predicting the acceleration requirement of the vehicle in the automatic driving mode, the transient control of the lock-up clutch 42 is performed before the backlash elimination control of the differential gear 48. Thereby, it is possible to suppress the parallel execution of the transient control of the lock-up clutch 42 and the backlash elimination control of the differential gear 48 during the subsequent acceleration of the vehicle, and suppress the driver from feeling the backlash shock in the differential gear 48.

[0023] In the above-described embodiment, the hybrid vehicle 20 includes the engine 22, the motor 30, the torque converter 41 having the lock-up clutch 42, and the automatic transmission 44. However, a vehicle configuration without the motor 30 may also be used.

[0024] As described above, the embodiments for carrying out the present disclosure have been described using embodiments. However, the present disclosure is not limited to such embodiments, and it goes without saying that the present disclosure can be implemented in various forms without departing from the gist of the present disclosure.

Industrial Applicability

[0025] The present disclosure can be used in the manufacturing industry of vehicles and the like.

Explanation of Signs

[0026] 20 Hybrid vehicle, 22 Engine, 41 Torque converter, 42 Lock-up clutch, 44 Automatic transmission, 48 Differential gear, 49a, 49b Drive wheels, 70 ECU.

Claims

【Claim 1】 A vehicle comprising: an engine; a torque converter connected to the engine and having a lock-up clutch; a transmission connected to the torque converter and connected to drive wheels via a differential gear; and a control device, When the control device predicts an acceleration request of the vehicle in an automatic driving mode, the control device performs transient control of the lock-up clutch prior to backlash elimination control of the differential gear. Vehicle.

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