Vehicle control devices

Abstract

The present invention provides a vehicle control device that appropriately corrects the indicated pressure of a lockup clutch through learning. During slip control of the lockup clutch, when it is determined that the actual value of the lockup clutch slip is limited within a predetermined range relative to a target value, a correction amount for the indicated pressure of the lockup clutch is obtained through feedback control. This correction amount is used to correct the indicated pressure of the lockup clutch set for the next slip control through learning. The predetermined range is set based on the target value of the lockup clutch slip. Therefore, compared to a case where the predetermined range is set to a constant value, it is easier to obtain the correction amount when the slip is actually limited. Thus, the indicated pressure of the lockup clutch can be appropriately corrected through learning.

Description

Technical Field

[0001] The present invention relates to a control device for a vehicle including a fluid transmission device with a lock-up clutch provided between a power source and drive wheels. Background Art

[0002] Vehicle control devices are widely known, including a power source and a fluid transmission device, the fluid transmission device being provided in a power transmission path between the power source and the drive wheels and having a lockup clutch. For example, Patent Document 1 discloses a control device for a lockup clutch. Patent Document 1 discloses that the indicated pressure at the start of release of the lockup clutch is corrected based on a learned correction value. This learned correction value is set by comparing the following value with a predetermined reference value: the value is obtained by subtracting the indicated pressure from the estimated pressure of the lockup clutch when the slip of the lockup clutch becomes less than a predetermined value when switching the lockup clutch from a released state to an engaged state.

[0003] Prior art literature

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2012-177434 Summary of the Invention

[0005] Technical problem to be solved by the invention

[0006] Furthermore, states where the lockup clutch slip is less than a specified value include states where the slip is zero due to the lockup clutch being engaged due to excessive lockup clutch hydraulic pressure. Therefore, it is possible that the lockup clutch hydraulic pressure cannot be appropriately corrected through learning. For example, consider a lockup clutch slip control in which the indicated pressure of the lockup clutch is corrected through feedback control to bring the lockup clutch slip to a target value. The correction value obtained through feedback control when the lockup clutch slip is limited to a specified range relative to the target value is used to correct the indicated pressure of the lockup clutch during the next slip control through learning. During this learning, if the specified range relative to the target slip includes a zero slip value, the lockup clutch may be judged as limited when the slip is zero. In this case, the lockup clutch is actually only fully engaged, not in a stable slip control state. Using the correction value obtained through feedback control when the lockup clutch slip is determined to be limited, it is possible that the lockup clutch hydraulic pressure cannot be appropriately corrected through learning.

[0007] The present invention has been made based on the above situation, and an object of the present invention is to provide a vehicle control device capable of appropriately correcting the indicated pressure of the lockup clutch through learning.

[0008] Technical solutions to solve problems

[0009] The gist of the first technical solution is a vehicle control device, (a) the vehicle includes a power source and a fluid transmission device, the fluid transmission device is provided in a power transmission path between the power source and the drive wheels, and has a lockup clutch, wherein the control device includes: (b) a lockup clutch control unit, which controls the lockup clutch to be in any one of a released state, a slipping state, and an engaged state, and, when the lockup clutch is controlled to be in the slipping state by setting the indicated pressure of the lockup clutch to achieve a target value of the slip amount, the lockup clutch is controlled by feedback control. (c) a learning control unit which, during the slip control, obtains a correction amount for the indicated pressure of the lockup clutch by the feedback control when it is determined that the actual value of the slip amount is limited to a prescribed range relative to the target value of the slip amount, and uses the correction amount to correct the indicated pressure of the lockup clutch set in the next slip control through learning, and (d) the learning control unit sets the prescribed range based on the target value of the slip amount.

[0010] Furthermore, a second invention provides the vehicle control device according to the first invention, wherein the learning control unit sets the predetermined range relative to the target value of the slip amount so that a zero value of the slip amount is not included in the predetermined range.

[0011] According to a third aspect, in the vehicle control device according to the second aspect, the learning control unit sets a predetermined range on the positive side of the target slippage amount and a predetermined range on the negative side of the target slippage amount to different values.

[0012] In addition, the fourth technical solution is based on the vehicle control device described in the third technical solution. When the target value of the slip amount is a positive value, the learning control unit sets the prescribed range on the negative side to a value smaller than the prescribed range on the positive side. On the other hand, when the target value of the slip amount is a negative value, the prescribed range on the positive side is set to a value smaller than the prescribed range on the negative side.

[0013] In addition, the fifth technical solution is based on the vehicle control device recorded in any one of the first to fourth technical solutions, and the learning control unit determines that the actual value of the slip amount is limited to the prescribed range when the state in which the actual value of the slip amount enters the prescribed range continues for more than a prescribed time.

[0014] Furthermore, a sixth aspect provides the vehicle control device according to any one of the first to fifth aspects, wherein the predetermined range is a predetermined threshold value that allows determination that the vehicle is being controlled to the intended slip state.

[0015] Effects of the Invention

[0016] According to the first technical solution, during slip control of the lockup clutch, when it is determined that the actual value of the slip amount of the lockup clutch is limited within a predetermined range relative to the target value, a correction amount for the indicated pressure of the lockup clutch is obtained by feedback control. This correction amount is used to correct the indicated pressure of the lockup clutch set in the next slip control through learning. The predetermined range is set based on the target value of the slip amount of the lockup clutch. Therefore, compared to a case where the predetermined range is set to a uniform value, it is easier to obtain the correction amount when the slip amount is actually limited. Thus, the indicated pressure of the lockup clutch can be appropriately corrected through learning.

[0017] Furthermore, according to the second aspect, the predetermined range is set relative to the target value of the slip amount of the lockup clutch so as not to include a zero slip value. Therefore, the correction amount when the slip amount is actually limited can be appropriately obtained.

[0018] In addition, according to the third technical solution, the prescribed range on the positive side of the target value of the slip amount of the lockup clutch and the prescribed range on the negative side of the target value of the slip amount are set to different values. Therefore, the prescribed range can be set relative to the target value of the slip amount so that the zero value of the slip amount is not included in the prescribed range.

[0019] In addition, according to the fourth technical solution, when the target value of the slip amount of the lock-up clutch is a positive value, the prescribed range on the negative side is set to a value smaller than the prescribed range on the positive side. On the other hand, when the target value of the slip amount is a negative value, the prescribed range on the positive side is set to a value smaller than the prescribed range on the negative side. Therefore, regardless of whether the target value of the slip amount of the lock-up clutch is a positive value or a negative value, the indicated pressure of the lock-up clutch can be appropriately corrected through learning.

[0020] Furthermore, according to the fifth technical solution, when the actual value of the slip amount of the lock-up clutch remains within the prescribed range for a period of time or longer, it is determined that the actual value of the slip amount is within the prescribed range. Therefore, a correction amount can be obtained for stably performing slip control.

[0021] Furthermore, according to the sixth aspect, the predetermined range is a predetermined threshold value that can be determined as being controlled in the intended slip state. Therefore, the indicated pressure of the lockup clutch can be appropriately corrected through learning. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The diagrams illustrate a schematic configuration of a vehicle to which the present invention is applied, and also illustrate control functions used for various controls in the vehicle and main parts of the control system.

[0023] Figure 2 FIG. 1 is a diagram showing an example of a time chart when the acceleration slip control is executed.

[0024] Figure 3 This is a diagram for explaining an example of a method of setting a predetermined range.

[0025] Figure 4 This is a flowchart for explaining a main portion of the control operation of the electronic control device, and is a flowchart for explaining the control operation for appropriately correcting the LU clutch instruction pressure through learning.

[0026] Figure 5 It means it has been executed Figure 4 The flowchart shown is a diagram of an example of a timing chart in the case of the control operation. DETAILED DESCRIPTION

[0027] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0028] [Example]

[0029] Figure 1 This figure is a diagram for explaining the schematic structure of a vehicle 10 to which the present invention is applied, and is a diagram for explaining the control functions and main parts of the control system used for various controls in the vehicle 10. Figure 1 In FIG, a vehicle 10 includes an engine 12 , drive wheels 14 , and a power transmission device 16 provided in a power transmission path between the engine 12 and the drive wheels 14 .

[0030] The engine 12 is the power source of the vehicle 10. The engine 12 is a well-known internal combustion engine such as a gasoline engine or a diesel engine. The engine 12 is controlled by an electronic control unit 80 (described later) which controls an engine control unit 50 provided in the vehicle 10 and includes a throttle actuator, a fuel injection device, an ignition device, and the like. This controls the engine torque Te, which is the output torque of the engine 12.

[0031] The power transmission device 16 includes a torque converter 20, an automatic transmission 22, and other components within a housing 18, a non-rotating component mounted on the vehicle body. The torque converter 20 is connected to the engine 12. The automatic transmission 22 is connected to the torque converter 20 and is interposed in the power transmission path between the torque converter 20 and the drive wheels 14. The power transmission device 16 also includes a propeller shaft 26 connected to a transmission output shaft 24, which is an output rotating component of the automatic transmission 22; a differential gear 28 connected to the propeller shaft 26; and a pair of drive shafts 30 connected to the differential gear 28. Furthermore, the power transmission device 16 includes an engine connecting shaft 32, which connects the engine 12 and the torque converter 20.

[0032] The torque converter 20 includes a pump impeller 20a connected to the engine connecting shaft 32 and a turbine impeller 20b connected to the transmission input shaft 34, which serves as the input rotating member of the automatic transmission 22. The pump impeller 20a is the input member of the torque converter 20, while the turbine impeller 20b is the output member of the torque converter 20. The engine connecting shaft 32 is also the input rotating member of the torque converter 20. The transmission input shaft 34 is also the output rotating member of the torque converter 20, integrally formed with the turbine shaft, which is rotationally driven by the turbine impeller 20b. The torque converter 20 is a fluid-type transmission device provided in the power transmission path between the engine 12 and the drive wheels 14, transmitting power from the engine 12 from the engine connecting shaft 32 to the transmission input shaft 34 via a fluid. The torque converter 20 includes an LU clutch 36 that connects the pump impeller 20a and the turbine impeller 20b, that is, connects the engine connecting shaft 32 and the transmission input shaft 34. The LU clutch 36 is a direct-connection clutch that couples the input and output rotating members of the torque converter 20 , that is, a well-known lockup clutch.

[0033] The LU clutch 36 is a hydraulic friction engagement device comprised of, for example, a multi-plate or single-plate clutch. The LU clutch 36 switches its operating state, or control state, by varying the LU torque Tlu in accordance with the LU hydraulic pressure PRlu, which is a regulated hydraulic pressure supplied from a hydraulic control circuit 52 included in the vehicle 10. The LU torque Tlu represents the torque capacity of the LU clutch 36.

[0034] The control states of the LU clutch 36 include a released state (also called a completely released state), a slipping state, and an engaged state (also called a completely engaged state). The released state is when the LU clutch 36 is released, the slipping state is when the LU clutch 36 is engaged with slipping, and the engaged state is when the LU clutch 36 is engaged. When the LU clutch 36 is in the released state, the torque converter 20 is in a torque converter state capable of achieving a torque amplification effect. Furthermore, when the LU clutch 36 is in the engaged state, the torque converter 20 is in a locked state, where the pump impeller 20a and the turbine impeller 20b rotate integrally.

[0035] The automatic transmission 22 is a well-known planetary gear automatic transmission, for example, comprising an engagement device CB and one or more planetary gear sets (not shown). The engagement device CB, for example, comprises a plurality of well-known hydraulic friction engagement devices. The engagement device CB switches control states such as an engaged state, a slipping state, and a released state by varying the CB torque Tcb, representing each torque capacity, in accordance with the CB hydraulic pressure PRcb, which is a regulated hydraulic pressure supplied from the hydraulic control circuit 52.

[0036] The automatic transmission 22 is a stepped transmission that establishes one of multiple shift speeds (also called gears) with different speed ratios (also called gear ratios) γat (=AT input speed Ni / AT output speed No) by engaging any of the engagement devices CB. The automatic transmission 22 switches gears based on the driver's (= driver's) accelerator operation, vehicle speed V, and other factors, using the electronic control unit 80 (described later). The AT input speed Ni is the rotational speed of the transmission input shaft 34, which is the input speed of the automatic transmission 22. The AT input speed Ni is the same value as the turbine speed Nt, which is the output speed of the torque converter 20, or the LU output speed, which is the output speed of the LU clutch 36. The AT input speed Ni can be represented by the turbine speed Nt. The AT output speed No is the rotational speed of the transmission output shaft 24, which is the output speed of the automatic transmission 22.

[0037] In the power transmission device 16, the power output from the engine 12 is transmitted from the engine connecting shaft 32 to the drive wheels 14 in this order through the torque converter 20, the automatic transmission 22, the propeller shaft 26, the differential gear 28, and the drive shaft 30. Unless otherwise specified, the meaning of the above-mentioned power is the same as driving force, torque, and force.

[0038] The vehicle 10 includes a mechanical oil pump, MOP 54. The MOP 54 is coupled to the pump impeller 20a and is rotationally driven by the engine 12 to discharge hydraulic oil OIL for use in the power transmission device 16. The hydraulic oil OIL discharged by the MOP 54 is supplied to the hydraulic control circuit 52. The hydraulic control circuit 52 supplies the CB hydraulic pressure PRcb, the LU hydraulic pressure PRlu, and the like, each regulated based on the hydraulic oil OIL discharged by the MOP 54.

[0039] The vehicle 10 further includes an electronic control unit 80, which comprises a control device for the vehicle 10. The electronic control unit 80 is configured, for example, as a so-called microcomputer including a CPU, RAM, ROM, and input / output interfaces. The CPU utilizes the temporary storage function of the RAM and processes signals according to programs pre-stored in the ROM, thereby executing various controls for the vehicle 10. The electronic control unit 80 may also include various computers for engine control, clutch control, transmission control, and the like, as needed.

[0040] Various signals based on detection values ​​from various sensors included in the vehicle 10 (e.g., the engine speed sensor 60, the turbine speed sensor 62, the output speed sensor 64, the accelerator position sensor 66, the throttle position sensor 68, the brake switch 70, and the oil temperature sensor 72) are provided to the electronic control unit 80. These signals include, for example, the engine speed Ne, which is the speed of the engine 12; the turbine speed Nt, which is the same value as the AT input speed Ni; the AT output speed No, which corresponds to the vehicle speed V; the accelerator position θacc, which is the driver's accelerator operation amount indicating the magnitude of the driver's accelerator operation; the throttle position θth, which is the opening of the electronic throttle; a brake operation (on) signal Bon, which indicates the state of the brake pedal being operated by the driver to apply the wheel brakes; and the hydraulic oil temperature THoil, which is the temperature of the hydraulic oil OIL in the hydraulic control circuit 52. The engine speed Ne is the same value as the input speed of the torque converter 20, that is, the LU input speed, which is the input speed of the LU clutch 36.

[0041] Various command signals (such as the engine control command signal Se for controlling the engine 12, the CB hydraulic control command signal Scb for controlling the engagement device CB, the LU hydraulic control command signal Slu for controlling the LU clutch 36, etc.) are output from the electronic control unit 80 to each device of the vehicle 10 (such as the engine control unit 50, the hydraulic control circuit 52, etc.).

[0042] The hydraulic control command signals S are described using the LU hydraulic control command signal Slu as an example. The electronic control unit 80 calculates the LU clutch indicated pressure Splu as the command value for the LU hydraulic pressure PRlu. The LU clutch indicated pressure Splu is the indicated pressure for the LU clutch 36, which is used to supply the regulated LU hydraulic pressure PRlu from the hydraulic control circuit 52. The indicated pressure is the target hydraulic pressure indicated by the electronic control unit 80 for the hydraulic oil OIL supplied to the engagement device. The actual hydraulic pressure, which is the actual hydraulic pressure supplied to the engagement device, varies according to the indicated pressure. The electronic control unit 80 converts the LU clutch indicated pressure Splu into an LU indicated current value Silu for driving the LU solenoid element SLlu included in the hydraulic control circuit 52. The LU solenoid element SLlu is a solenoid valve for the LU clutch 36 that outputs the LU hydraulic pressure PRlu. The LU indicated current value Silu is the indicated current for the solenoid driver, which serves as a drive circuit included in the electronic control unit 80 and drives the LU solenoid element SLlu. The LU hydraulic control command signal Slu is a drive current or voltage used by the solenoid driver to drive the LU solenoid SLlu based on the LU command current value Silu. Specifically, the LU clutch command pressure Splu is converted into the LU hydraulic control command signal Slu and output to the hydraulic control circuit 52. In this embodiment, for ease of explanation, the LU clutch command pressure Splu and the LU hydraulic control command signal Slu are treated synonymously.

[0043] To implement various controls in the vehicle 10 , the electronic control unit 80 includes an engine control unit 82 , a transmission control unit 84 , an LU clutch control unit 86 , and a learning control unit 88 .

[0044] The engine control unit 82 is a power source control unit, or power source control unit, that controls the operation of the engine 12, serving as a power source. The engine control unit 82 calculates the driver's drive demand for the vehicle 10 by, for example, applying the accelerator position θacc and the vehicle speed V to a drive demand map. The drive demand map is a relationship previously determined and stored experimentally or by design, i.e., a predetermined relationship. For example, the drive demand is the required drive torque Trdem at the drive wheels 14. Alternatively, the required drive force Frdem [N] at the drive wheels 14 or the required automatic transmission output torque at the transmission output shaft 24 may be used as the drive demand. When calculating the drive demand, the automatic transmission output speed No may be used in place of the vehicle speed V. The engine control unit 82 outputs an engine control command signal Se to the engine control device 50 to control the engine 12 so as to achieve the required drive torque Trdem, taking into account transmission losses, auxiliary machine loads, the gear ratio γat of the automatic transmission 22, and other factors.

[0045] The transmission control unit 84 uses, for example, a predetermined relationship, as a shift map to determine whether to shift the automatic transmission 22. The transmission control unit 84 outputs a CB hydraulic pressure control command signal Scb to the hydraulic control circuit 52, which is used to execute shift control of the automatic transmission 22 as needed, that is, based on the results of this shift determination. During the shift control of the automatic transmission 22, the transmission control unit 84 shifts the automatic transmission 22 by, for example, switching the release-side engagement device of the engagement device CB to the released state and switching the engagement-side engagement device of the engagement device CB to the engaged state. The shift map, for example, includes a predetermined relationship of shift lines for determining shifts in the automatic transmission 22 on a two-dimensional coordinate system with vehicle speed V and required drive torque Trdem as variables. In the shift map, the AT output speed No, etc., may be used in place of vehicle speed V, and the required drive force Frdem, accelerator opening θacc, throttle opening θth, etc., may be used in place of required drive torque Trdem.

[0046] The LU clutch control unit 86 controls the LU clutch 36, specifically, controls the control state of the LU clutch 36 to be in one of a released state, a slipping state, and an engaged state. Specifically, the LU clutch control unit 86 determines a control region using, for example, a predetermined relationship, such as a lockup region map, and outputs an LU hydraulic pressure control command signal Slu to the hydraulic control circuit 52. This LU hydraulic pressure control command signal Slu is used to supply the LU clutch 36 with an LU hydraulic pressure PRlu that achieves the control state corresponding to the determined control region. The lockup region map, for example, has a predetermined relationship on a two-dimensional coordinate system with vehicle speed V and required drive torque Trdem as variables, including a completely released region (i.e., a lockup cancellation (off) region), a slipping region, and a completely engaged region (i.e., a lockup region).

[0047] When the LU clutch control unit 86 determines that the control range is the lockup range, it executes lockup control of the LU clutch 36 by setting the LU hydraulic pressure PRlu to obtain an LU torque Tlu capable of transmitting the input torque, i.e., the LU input torque Tinlu, to the LU clutch 36, thereby fully engaging the LU clutch 36. The LU input torque Tinlu is, for example, the engine torque Te. The LU torque Tlu capable of transmitting the LU input torque Tinlu is, for example, a torque value obtained by multiplying the LU input torque Tinlu by a safety factor (>1).

[0048] When the LU torque Tlu is smaller than the LU input torque Tinlu, slip occurs in the LU clutch 36. If the LU clutch control unit 86 determines that the control range is the slip range, it performs LU slip control, which sets the LU hydraulic pressure PRlu to the LU input torque Tinlu to achieve the target LU slip amount Nslplut, which is the target value for the slip amount of the LU clutch 36, or LU slip amount Nslplut. The intended slip state of the LU clutch 36 is the target slip state that achieves the target LU slip amount Nslplut. In other words, the LU clutch control unit 86 performs LU slip control, which sets the LU clutch instruction pressure Splu to achieve the target LU slip amount Nslplut, and controls the LU clutch 36 to achieve the slip state. The LU slip amount Nslplu is the speed difference (=Ne - Nt) between the LU input speed (=engine speed Ne) and the LU output speed (=turbine speed Nt). In the lock-up range diagram, the slipping range is, for example, a range set in a lower vehicle speed range than the lock-up range to improve energy efficiency and drivability by implementing a slipping state in a range where lock-up control is difficult. Alternatively, the slipping range may be set based on drivability, cavity resonance, and other factors (e.g., noise and vibration (NV) performance).

[0049] LU slip control includes acceleration slip control and deceleration slip control. Acceleration slip control controls the LU clutch 36 to maintain a slipping state during vehicle start-up (from accelerator off to accelerator on), during steady-state driving with the accelerator on, or during acceleration caused by increased accelerator depression. This can, for example, suppress a sudden increase in engine speed Ne when the vehicle 10 is in a driving state, thereby reducing vehicle interior resonance noise. Deceleration slip control controls the LU clutch 36 to cause the engine 12 to follow the transmission input shaft 34 during deceleration with the accelerator off. This expands the fuel cutoff region in which, for example, a fuel cutoff operation, which stops fuel supply to the engine 12, can be performed when the vehicle 10 is in a driving state. Through LU slip control, the LU slip amount Nslplu is appropriately controlled, thereby achieving, for example, a balance between improved energy efficiency and improved NV performance.

[0050] Figure 2 : is a diagram showing an example of a time chart when the acceleration slip control is executed when the LU clutch 36 is shifted from the released state to the slip state. Figure 2In the figure, time t1a indicates the time when backlash elimination control of the LU clutch 36, i.e., LU backlash elimination control, is initiated, for example, when the control range is determined to have reached the slip range during acceleration. Backlash elimination control is a control that brings the friction engagement device to a backlash elimination complete state, eliminating the backlash between the friction plates, etc., of the friction engagement device. The backlash elimination complete state of the friction engagement device occurs when the hydraulic pressure supplied to the friction engagement device is increased from this backlash elimination complete state, causing the friction engagement device to begin to have torque capacity. During the LU clearance elimination control, first, to improve the initial responsiveness of the LU hydraulic pressure PRlu, a quick apply (QA (quick apply)) is executed, outputting a temporarily high quick fill pressure (see time t1a - time t2a). Next, to complete clearance elimination of the LU clutch 36, a constant pressure standby mode is executed, outputting a constant pressure standby pressure lower than the quick fill pressure (see time t2a - time t3a). After the predetermined QA time and constant pressure standby time, which are required for LU clearance elimination control, have elapsed from the start of the LU clearance elimination control, the acceleration slip control begins (see time t3a). During the acceleration slip control, a sweep-up operation is executed, gradually increasing the LU clutch command pressure Splu so that the actual LU slip amount Nslplur, representing the actual value of the LU slip amount Nslplu, approaches the target LU slip amount Nslplut (see time t3a - time t4a). Then, LU slip control is executed to output the LU clutch instruction pressure Splu for making the actual LU slip amount Nslplur equal to the target LU slip amount Nslplut (see time t4a and thereafter).

[0051] The LU clutch control unit 86 corrects the LU clutch instruction pressure Splu by feedback (=FB) control when performing LU slip control so that the actual LU slip amount Nslplur becomes the target LU slip amount Nslplut. The LU clutch control unit 86 corrects the LU clutch instruction pressure Splu, for example, for making the actual LU slip amount Nslplur become the target LU slip amount Nslplut, by FB control. Figure 2The LU clutch control unit 86 corrects the LU clutch indicated pressure Splu during the LU slip control shown after time t4a. Specifically, the LU clutch control unit 86 corrects the LU clutch indicated pressure Splu by adding the hydraulic FB value Splufb, which is the FB amount, to the hydraulic FF value Spluff, which is the feedforward (=FF) amount of the LU clutch indicated pressure Splu, as shown in the following equation (1). In the following equation (1), "Spluff" is the hydraulic FF value of the LU clutch indicated pressure Splu used to make the actual LU slip amount Nslplur equal to the target LU slip amount Nslplut, and "Splufb" is the hydraulic FB value, which is the correction amount used to correct the hydraulic FF value Spluff and is used to correct the LU clutch indicated pressure Splu by FB control. The LU clutch control unit 86 calculates the hydraulic FF value Spluff, for example, using a map or function that predetermines values ​​corresponding to the LU input torque Tinlu and the target LU slip amount Nslplut. The map or function is predetermined so that, for example, the hydraulic FF value Spluff becomes larger as the LU input torque Tinlu increases. The LU clutch control unit 86 calculates the hydraulic FB value Splufb using, for example, the following equation (2). Equation (2) is a predetermined FB control equation having a proportional term (P component), an integral term (I component), and a differential term (D component). In Equation (2), the first term on the right side is the proportional term, the second term on the right side is the integral term, and the third term on the right side is the differential term. "ΔNs" is the slip difference (= Nslplur - Nslplut), which is the difference between the actual LU slip amount Nslplur and the target LU slip amount Nslplut. "Kp" is the proportional constant (gain), "Ki" is the integral constant (gain), and "Kd" is the differential constant (gain).

[0052] Splu=Spluff+Splufb ··· (1)

[0053] Splufb=Kp×ΔNs+Ki×∫(ΔNs)dt+Kd×d(ΔNs) / dt···(2)

[0054] During LU slip control, the learning control unit 88 acquires a hydraulic FB value when it determines that the actual LU slip amount Nslplur is within a predetermined range RNGf relative to the target LU slip amount Nslplut. The learning control unit 88 uses the acquired hydraulic FB value to correct the LU clutch command pressure Splu set for the next LU slip control through learning. The hydraulic FB value is a learned value used to learn the LU clutch command pressure Splu. The LU clutch command pressure Splu set for the next LU slip control is, for example, a hydraulic FF value Spluff calculated using a predetermined map or function. The learning control unit 88 adds the hydraulic FB value to the hydraulic FF value Spluff (Tinlu, Nslplut) corresponding to the LU input torque Tinlu and the target LU slip amount Nslplut in a predetermined map used in the current LU slip control, for example, thereby rewriting the hydraulic FF value Spluff (Tinlu, Nslplut) in the map. The predetermined range RNGf is, for example, a predetermined threshold value that allows determination that the LU clutch 36 is controlled to the intended slip state. By learning the LU clutch instruction pressure Splu that allows the LU slip amount Nslplu to be appropriately controlled during LU slip control, for example, individual variations and aging degradation can be addressed.

[0055] The actual LU slide amount Nslplur may temporarily fall within the prescribed range RNGf due to the influence of noise, or when the actual LU slide amount Nslplur fluctuates significantly. In such cases, it cannot be said that the actual LU slide amount Nslplur is within the prescribed range RNGf. Therefore, the learning control unit 88 determines that the actual LU slide amount Nslplur is within the prescribed range RNGf if the actual LU slide amount Nslplur remains within the prescribed range RNGf for a prescribed time TMf or longer. The prescribed time TMf is a predetermined threshold used to determine whether LU slide control is in a stable state.

[0056] Furthermore, during learning using the hydraulic pressure FB value, if the same prescribed range RNGf is used regardless of the target LU slip amount Nslplut to determine whether the actual LU slip amount Nslplur is within the prescribed range RNGf, there is a possibility that the actual LU slip amount Nslplur is determined to be within the prescribed range RNGf when LU slip control is not being stably performed. For example, if the actual LU slip amount Nslplur is zero, the LU clutch 36 is actually only in the fully engaged state, not in a state of stable LU slip control. If the prescribed range RNGf includes a zero value for the LU slip amount Nslplu relative to the target LU slip amount Nslplut, and if the actual LU slip amount Nslplur is determined to be within the prescribed range RNGf when it is zero and the hydraulic pressure FB value at that time is used, there is a possibility that the LU clutch instruction pressure Splu will not be appropriately corrected through learning.

[0057] Then, the learning control unit 88 sets the predetermined range RNGf based on the target LU slip amount Nslplut.

[0058] Figure 3 This is a diagram illustrating an example of a method for setting the predetermined range RNGf. Figure 3 In the drawings, reference numerals “α(>0)”, “β(>0)”, “Nslplut1(>0)”, and “Nslplut2(>0)” are used, and values ​​given the same reference numerals indicate that the absolute values ​​are the same.

[0059] In this embodiment A, a predetermined range RNGf is set that is "±α" relative to the first target LU slip amount Nslplut1. In this embodiment A, neither the positive predetermined range RNGf (+α) nor the negative predetermined range RNGf (-α) includes a zero value for the LU slip amount Nslplu. Therefore, in this embodiment A, when the actual LU slip amount Nslplur is zero, it is not determined to be within the predetermined range RNGf.

[0060] Meanwhile, in Comparative Example A, a predetermined range RNGf of ±α is set for the second target LU slip amount Nslplut2, which is smaller than the first target LU slip amount Nslplut1, similar to Example A. However, unlike Example A, the predetermined range RNGf on the negative side of -α includes the zero value of the LU slip amount Nslplu. Therefore, in Comparative Example A, when the actual LU slip amount Nslplur is zero, it may be determined that the actual LU slip amount Nslplur is within the predetermined range RNGf. Consequently, in Comparative Example A, there is a risk that the LU clutch instruction pressure Splu cannot be appropriately corrected through learning.

[0061] In contrast to Comparative Example A, in Example B, the second target LU slip amount Nslplut2 is set to a predetermined range RNGf of "+α" on the positive side, similar to Comparative Example A. However, a predetermined range RNGf of "-β" is set on the negative side, unlike Comparative Example A. "β" is a value smaller than "α" and is set so that the negative predetermined range RNGf does not include the zero value of the LU slip amount Nslplu. Therefore, in Example B, when the actual LU slip amount Nslplur is zero, it is not determined to be within the predetermined range RNGf.

[0062] Meanwhile, in Comparative Example B, for the negative second target LU slip amount Nslplut2, whose sign is reversed from that of Example B, a predetermined range RNGf on the positive side (+α) and a predetermined range RNGf on the negative side (-β) are set, similar to Example B. However, unlike Example B, in Comparative Example B, the predetermined range RNGf on the positive side (+α) includes the zero value of the LU slip amount Nslplu. Therefore, in Comparative Example B, when the actual LU slip amount Nslplur is zero, it may be determined that the actual LU slip amount Nslplur is within the predetermined range RNGf. Consequently, in Comparative Example B, there is a risk that the LU clutch instruction pressure Splu may not be appropriately corrected through learning.

[0063] In contrast to Comparative Example B, in Example C, a positive predetermined range RNGf (+β) and a negative predetermined range RNGf (−α) are set for the negative second target LU slide amount Nslplut2. Specifically, in Example C, a value "β" smaller than "α" is set as the positive predetermined range RNGf for the negative second target LU slide amount Nslplut2. Therefore, in Example C, the actual LU slide amount Nslplur is not determined to be within the predetermined range RNGf when it is zero.

[0064] In this manner, the learning control unit 88 sets the prescribed range RNGf relative to the target LU slip amount Nslplut so that the zero value of the LU slip amount Nslplu is not included in the prescribed range RNGf. For example, the learning control unit 88 sets the prescribed range RNGf on the positive side of the target LU slip amount Nslplut to different values ​​than the prescribed range RNGf on the negative side of the target LU slip amount Nslplut. Specifically, when the target LU slip amount Nslplut is a positive value, the learning control unit 88 sets the prescribed range RNGf on the negative side to a value smaller than the prescribed range RNGf on the positive side. On the other hand, when the target LU slip amount Nslplut is a negative value, the learning control unit 88 sets the prescribed range RNGf on the positive side to a value smaller than the prescribed range RNGf on the negative side.

[0065] More specifically, the learning control unit 88 determines whether LU slip control is being implemented by the LU clutch control unit 86. If the learning control unit 88 determines that LU slip control is being implemented, it determines whether a basic learning condition, one of the learning conditions for learning the LU clutch instruction pressure Splu, is satisfied. The basic learning condition is a learning condition that is different from the learning value acquisition condition described below. Examples of the basic learning condition include conditions such as the operating oil temperature THoil being at room temperature after warm-up, the vehicle speed V being at or above a stable medium speed, and the engine torque Te being within a stable torque range. If the learning control unit 88 determines that LU slip control is being implemented, it determines whether a learning value acquisition condition, different from the basic learning condition, is satisfied. The learning value acquisition condition is a condition that the actual LU slip amount Nslplur is limited to a specified range RNGf set based on the target LU slip amount Nslplut.

[0066] When the learning control unit 88 determines that the learning conditions (learning basic conditions and learning value acquisition conditions) are met while LU slip control is being executed, it acquires and stores the hydraulic pressure FB value as a learned value. Learning control unit 88 uses the hydraulic pressure FB value to correct the hydraulic pressure FF value Spluff during the next LU slip control through learning.

[0067] Figure 4 This is a flowchart explaining a main part of the control operation of the electronic control device 80 , and is a flowchart explaining a control operation for appropriately correcting the LU clutch instruction pressure Splu by learning, and is, for example, repeatedly executed. Figure 5 It means it has been executed Figure 4 The flowchart shown is a diagram of an example of a timing chart in the case of the control operation.

[0068] exist Figure 4In the flowchart, each step corresponds to the function of the learning control unit 88. In step (step omitted below) S10, it is determined whether LU slip control is being implemented. If the judgment of S10 is negative, this routine ends. If the judgment of S10 is positive, it is determined in S20 whether the basic learning condition is met. If the judgment of S20 is negative, this routine ends. If the judgment of S20 is positive, it is determined in S30 whether the learning value acquisition condition is met, that is, whether the actual LU slip amount Nslplur is limited to the prescribed range RNGf set based on the target LU slip amount Nslplut. If the judgment of S30 is negative, this routine ends. If the judgment of S30 is positive, the hydraulic FB value as the learning value is acquired and stored in S40.

[0069] Figure 5 1 is a diagram showing an example of a case where the LU clutch instruction pressure Splu is learned during the implementation of the acceleration slip control. Figure 5In the figure, time t1b indicates the moment when the accelerator pedal-increasing operation is initiated during acceleration with the accelerator pedal held on. Although slip control is in effect, the engine torque Te increases sharply with the accelerator pedal-increasing operation, temporarily causing a sharp increase in engine speed Ne (see time t1b and onward). Consequently, the hydraulic pressure FB value increases sharply, controlling the actual LU slip amount Nslplur to the target LU slip amount Nslplut (see time t1b - time t2b). At this point, the sharp increase in the hydraulic pressure FB value does not immediately become negative, so the actual LU slip amount Nslplur falls below the target LU slip amount Nslplut due to the increase in the LU clutch command pressure Splu. At this point, regardless of how much the LU clutch command pressure Splu increases, the LU clutch 36 is fully engaged, and the actual LU slip amount Nslplur does not fall below zero. In the comparative example, a predetermined range RNGf is set to the same value on both the positive side (see the solid arrow a) and the negative side (see the dashed arrow b). When the actual LU slip amount Nslplur is zero, it is determined to be within the predetermined range RNGf, and a hydraulic FB value is acquired (see time t2b). When the hydraulic FB value acquired at this time is used to learn the LU clutch indicated pressure Splu, a positive hydraulic FB value is used regardless of whether the actual LU slip amount Nslplur is lower than the target LU slip amount Nslplut. Therefore, a correction is made to increase the next hydraulic FF value Spluff. Repeated corrections achieved through such learning could lead to an excessive increase in the next hydraulic FF value Spluff, resulting in an excessive LU clutch indicated pressure Splu and a sudden engagement shock of the LU clutch 36. This phenomenon is more likely to occur when the target LU slip amount Nslplut is small. In contrast, in this embodiment, the target LU slip amount Nslplut is set based on the predetermined range RNGf. For example, since the target LU slip amount Nslplut is a positive value, in this embodiment, the negative predetermined range RNGf (see the dashed arrow d) is set to a value smaller than the positive predetermined range RNGf (see the solid arrow c). Consequently, when the actual LU slip amount Nslplur is zero, the actual LU slip amount Nslplur does not fall within the predetermined range RNGf (see time t2b - time t3b). Therefore, when the target LU slip amount Nslplut is small, the hydraulic pressure FB value in the state where the LU clutch 36 is fully engaged due to excessive LU clutch instruction pressure Splu and the actual LU slip amount Nslplur is zero is not used for learning the LU clutch instruction pressure Splu.In this embodiment, when the actual LU slip amount Nslplur enters the specified range RNGf on the negative side (refer to the dotted arrow d) and lasts for more than the specified time TMf, the hydraulic FB value (refer to time t4b) is obtained and the hydraulic FB value is used to appropriately implement the learning of the LU clutch indicated pressure Splu.

[0070] As described above, according to this embodiment, when learning the LU clutch command pressure Splu during LU slip control, the prescribed range RNGf is set based on the target LU slip amount Nslplut. Therefore, compared to a case where the prescribed range RNGf is set to a uniform value, it is easier to obtain the hydraulic pressure FB value when the actual LU slip amount Nslplur is effectively limited, that is, when LU slip control is stabilized. This allows for appropriate correction of the LU clutch command pressure Splu through learning. In other words, even in a case where the region where the actual LU slip amount Nslplur can be determined to be limited differs based on the target LU slip amount Nslplut, it is possible to set an appropriate prescribed range RNGf without incorrect learning.

[0071] Furthermore, according to this embodiment, the predetermined range RNGf is set relative to the target LU slip amount Nslplut so that the zero value of the LU slip amount Nslplu is not included in the predetermined range RNGf. Therefore, the hydraulic pressure FB value when the actual LU slip amount Nslplur is actually limited can be appropriately obtained.

[0072] In addition, according to this embodiment, the prescribed range RNGf on the positive side relative to the target LU sliding amount Nslplut and the prescribed range RNGf on the negative side relative to the target LU sliding amount Nslplut are set to different values. Therefore, the prescribed range RNGf can be set relative to the target LU sliding amount Nslplut so that the zero value of the LU sliding amount Nslplu is not included in the prescribed range RNGf.

[0073] In addition, according to the present embodiment, when the target LU slip amount Nslplut is a positive value, the prescribed range RNGf on the negative side is set to a value smaller than the prescribed range RNGf on the positive side. On the other hand, when the target LU slip amount Nslplut is a negative value, the prescribed range RNGf on the positive side is set to a value smaller than the prescribed range RNGf on the negative side. Therefore, regardless of whether the target LU slip amount Nslplut is a positive value or a negative value, the LU clutch indicated pressure Splu can be appropriately corrected through learning.

[0074] In addition, according to this embodiment, when the actual LU slip amount Nslplur enters the specified range RNGf for more than the specified time TMf, it is determined that the actual LU slip amount Nslplur is limited to the specified range RNGf, so the hydraulic pressure FB value when the LU slip control is stably performed can be obtained.

[0075] Furthermore, according to the present embodiment, the predetermined range RNGf is a predetermined threshold value that can determine that the LU clutch 36 is controlled to the intended slip state. Therefore, the LU clutch instruction pressure Splu can be appropriately corrected through learning.

[0076] The embodiments of the present invention have been described in detail above based on the accompanying drawings, but the present invention can also be applied to other technical solutions.

[0077] For example, in the aforementioned embodiment, the hydraulic pressure FB value at the time when the actual LU slip amount Nslplur remains within the predetermined range RNGf for a period of time TMf or longer is acquired as the learned value, but the present invention is not limited to this embodiment. For example, the hydraulic pressure FB value acquired each control cycle may be updated as the learned value while the learning condition is satisfied from the time when the actual LU slip amount Nslplur remains within the predetermined range RNGf for a period of time TMf or longer.

[0078] Furthermore, while the aforementioned embodiments illustrate the engine 12 as the power source, the present invention is not limited to this embodiment. For example, an electric motor may be used in addition to or in place of the engine 12. This means that the present invention can be applied to a vehicle powered solely by an engine, an electric vehicle powered solely by an electric motor, or a hybrid vehicle powered by both an engine and an electric motor, in either a parallel or series configuration.

[0079] Furthermore, while the aforementioned embodiment illustrates a planetary gear automatic transmission as the automatic transmission 22, the present invention is not limited to this embodiment. For example, the automatic transmission 22 may also be a synchromesh-type parallel two-shaft automatic transmission, including the well-known DCT (Dual Clutch Transmission), or a well-known belt-type continuously variable transmission. Furthermore, the automatic transmission 22 is not necessarily required.

[0080] Furthermore, while the aforementioned embodiment utilizes a torque converter 20 as a fluid transmission device, the present invention is not limited to this embodiment. For example, a fluid coupling, which lacks a torque-amplifying function, or another fluid transmission device may be used in place of the torque converter 20. In short, the present invention is applicable to any vehicle equipped with a power source and a fluid transmission device having a lockup clutch, disposed in the power transmission path between the power source and the drive wheels.

[0081] The above-mentioned content is merely one embodiment, and the present invention can be implemented in various ways by adding various changes and improvements based on the knowledge of those skilled in the art.

[0082] [Description of Reference Numerals]

[0083] 10: Vehicles

[0084] 12: Engine (power source)

[0085] 14: driving wheel

[0086] 20: Torque converter (fluid transmission device)

[0087] 36: LU clutch (locking clutch)

[0088] 80: Electronic control unit (control unit)

[0089] 84: Transmission control unit

[0090] 86: LU clutch control unit (lock-up clutch control unit)

Claims

1. A control device (80) for a vehicle (10), wherein the vehicle (10) comprises a power source (12) and a fluid transmission device (20), wherein the fluid transmission device (20) is provided in a power transmission path between the power source (12) and a drive wheel (14), and comprises a lockup clutch (36), wherein: The control device (80) comprises: a lockup clutch control unit (86) for controlling the lockup clutch (36) to be in any one of a released state, a slipping state, and an engaged state, and, when performing slip control for controlling the lockup clutch (36) to be in the slipping state by setting an indicated pressure of the lockup clutch (36) for achieving a target value (Nslplut) of a slip amount (Nslplu), correcting the indicated pressure (Splu) of the lockup clutch (36) by feedback control so that an actual value (Nslplur) of the slip amount (Nslplu) becomes a target value (Nslplut) of the slip amount (Nslplu), wherein the slip amount (Nslplu) is a speed difference (Ne-Nt) between an input speed (Ne) and an output speed (Nt) of the lockup clutch (36); and a learning control unit (88) which, when determining that the actual value (Nslplur) of the slip amount (Nslplu) is limited within a predetermined range (RNGf) relative to the target value (Nslplut) of the slip amount (Nslplu), obtains a correction amount for the indicated pressure (Splu) of the lockup clutch (36) by the feedback control, and uses the correction amount to correct the indicated pressure (Splu) of the lockup clutch (36) set in the next slip control by learning, The learning control unit (88) sets the prescribed range (RNGf) based on the target value (Nslplut) of the slip amount (Nslplu).

2. The control device (80) of the vehicle (10) according to claim 1, characterized in that The learning control unit (88) sets the prescribed range (RNGf) relative to the target value (Nslplut) of the slip amount (Nslplu) so that the zero value of the slip amount (Nslplu) is not included in the prescribed range (RNGf).

3. The control device (80) of the vehicle (10) according to claim 2, characterized in that The learning control unit (88) sets a predetermined range on the positive side of the target value (Nslplut) of the sliding amount (Nslplu) and a predetermined range on the negative side of the target value (Nslplut) of the sliding amount (Nslplu) to different values.

4. The control device (80) of the vehicle (10) according to claim 3, characterized in that The learning control unit (88) sets the prescribed range on the negative side to a value smaller than the prescribed range on the positive side when the target value (Nslplut) of the sliding amount (Nslplu) is a positive value, and on the other hand, sets the prescribed range on the positive side to a value smaller than the prescribed range on the negative side when the target value (Nslplut) of the sliding amount (Nslplu) is a negative value.

5. The control device (80) of a vehicle (10) according to any one of claims 1 to 4, characterized in that: The learning control unit (88) determines that the actual value (Nslplur) of the sliding amount (Nslplu) is limited to the prescribed range (RNGf) when the state in which the actual value (Nslplur) of the sliding amount (Nslplu) enters the prescribed range (RNGf) continues for more than a prescribed time (TMf).

6. The control device (80) of a vehicle (10) according to any one of claims 1 to 5, characterized in that: The predetermined range (RNGf) is a predetermined threshold value that can be determined as a sliding state that is controlled as intended.

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