JP2020007949A - Traction control device of vehicle - Google Patents

Abstract

To provide a traction control device which is employed to a vehicle comprising a torque converter having a lockup mechanism, and high in responsiveness on the basis of an engagement state of the lockup mechanism.SOLUTION: A traction control device is employed to a vehicle comprising a torque converter having a lockup mechanism in a power transmission path between a power source and a transmission. The traction control device limits outputs so as to suppress an excessive acceleration slip of drive wheels to which the outputs from the power source are transmitted. The traction control device includes: a calculation part QS for calculating a requirement value Qs for limiting the outputs on the basis of the acceleration slip Sw; a determination part HN for determining an engagement state Hn of the lockup mechanism; and an adjustment part CQ for performing a reduction adjustment so that the requirement value Qs becomes small when the lockup mechanism is released rather than the case that the lockup mechanism is constricted on the basis of the engagement state Hn.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a traction control device for a vehicle.

  Patent Document 1 discloses that, when traction control operation is determined so as to avoid interference between traction control and slip control of a vehicle lock-up clutch, the torque transmission state of the lock-up clutch is determined by a torque transmission state holding unit. Is held as it is. According to Patent Literature 1, during traction control, torque change due to slip control does not occur, so that control interference does not occur. Therefore, the torque change due to the traction control is not amplified or canceled, and the traction control is stabilized, and the slip control can be performed stably without being affected by the change in the throttle valve opening due to the traction control. .

  Patent Literature 2 discloses that when traction control for limiting at least one of the output and the rotation speed of the engine is performed, the torque converter is always locked up. It is described that the sex can be maintained.

  In the above patent document, the torque converter is locked up when the traction control is being executed, but there are cases where the lockup needs to be released (for example, at the time of starting, at the time of creep running, at the time of shifting). By the way, in a torque converter (fluid converter) provided with a lock-up mechanism, the transmission path of the output (power) of the power source differs between the case where the lock-up mechanism is restrained and the case where the lock-up mechanism is released. When the lock-up mechanism is released, power is transmitted to the transmission via fluid in the fluid converter. On the other hand, when the lock-up mechanism is restricted, power is transmitted directly to the transmission without passing through the fluid. When power is transmitted to drive wheels via fluid, there may be a time delay in the power transmission path. For this reason, it is desired that the traction control is executed in consideration of the engagement state of the lock-up mechanism.

JP-A-8-28687 JP 2009-190505 A

  An object of the present invention is to provide a traction control device which is applied to a vehicle including a torque converter having a lock-up mechanism and has a high response based on an engagement state of the lock-up mechanism.

  A traction control device (TS) for a vehicle according to the present invention includes a vehicle including a torque converter (TC) having a lock-up mechanism (LU) in a power transmission path between a power source (EN) and a transmission (TM). Applied to The traction control device (TS) limits the output (Qa) so as to suppress excessive acceleration slip (Sw) of the drive wheels (WHf, WHr) to which the output (Qa) of the power source (EN) is transmitted. A calculation unit (QS) for calculating a required value (Qs) for limiting the output (Qa) based on the acceleration slip (Sw), and an engagement state of the lock-up mechanism (LU). When the lock-up mechanism (LU) is released (Fh = 1) based on the determination unit (HN) that determines (Hn) and the engagement state (Hn), the lock-up mechanism (LU) ) Is constrained (Fh = 0), and an adjustment unit (CQ) that performs a decrease adjustment so that the required value (Qs) becomes smaller. For example, in the traction control device (TS), the adjustment unit (CQ) performs the decrease adjustment of the request value (Qs) only when the vehicle starts moving.

  According to the above configuration, the required output (required value) Qs is adjusted to be smaller in the released state of the lock-up mechanism LU than in the restricted state of the lock-up mechanism LU so that the torque converter TC is in the engaged state. The resulting time delay of power transmission from power Qa to drive torque Tq is compensated. As a result, excessive acceleration slip Sw of the drive wheel WHf is quickly suppressed, and the convergence of the drive wheels WHf and WHr is improved. Furthermore, since the decrease adjustment of the required output Qs is limited to when the vehicle starts (for example, shifting from the first speed to the second speed), the reliability of control execution can be ensured.

1 is an overall configuration diagram of a vehicle equipped with a vehicle traction control device TS according to the present invention. FIG. 4 is a schematic diagram for explaining transmission of power Qa via torque converter TC. It is a functional block diagram for explaining an outline of traction control device TS. FIG. 4 is a functional block diagram for explaining a first processing example of drive torque control in the traction control device TS. FIG. 9 is a functional block diagram for explaining a second processing example of drive torque control in the traction control device TS. FIG. 8 is a time-series diagram for explaining processing in a decrease amount calculation block SG.

<Symbols of components, etc., and subscripts at the end of the symbols>
In the following description, components, operation processing, signals, characteristics, and values having the same reference numerals, such as “ECU”, have the same function. The suffixes “f” and “r” attached to the end of the symbol related to each wheel are generic symbols indicating “f” for the front wheel and “r” for the rear wheel. For example, in a wheel speed sensor, it is described as a front wheel speed sensor VWf and a rear wheel speed sensor VWr. Further, the suffixes “f” and “r” at the end of the symbol may be omitted. When the suffixes “f” and “r” are omitted, each symbol represents its generic name. For example, "VW" represents each wheel speed sensor.

<Overall configuration of vehicle provided with traction control device TS according to the present invention>
A vehicle equipped with the vehicle traction control device TS according to the present invention will be described with reference to the overall configuration diagram of FIG. In the vehicle, the drive device YD is connected to the front wheels WHf via the drive shaft DS. In other words, the vehicle is a front-wheel drive vehicle in which the front wheels WHf are used as drive wheels.

  The vehicle includes a braking operation member BP, a braking operation amount sensor BA, an acceleration operation member AP, an acceleration operation amount sensor AA, a shift operation member HP, a shift position sensor HA, a steering operation member SW, a steering angle sensor SA, and a wheel speed sensor VW. , A yaw rate sensor YR, a longitudinal acceleration sensor GX, a lateral acceleration sensor GY, a braking device YB, and a driving device YD.

  The braking operation member (for example, a brake pedal) BP is a member that the driver operates to decelerate the vehicle. By operating the braking operation member BP, the braking torque Bq for the wheel WH is adjusted, and a braking force is generated on the wheel WH.

  A brake operation amount sensor BA is provided to detect an operation amount Ba of the brake operation member (brake pedal) BP by the driver. Specifically, as the braking operation amount sensor BA, a master cylinder hydraulic pressure sensor PM for detecting a hydraulic pressure (master cylinder hydraulic pressure) Pm in the master cylinder CM, and an operation displacement sensor for detecting an operation displacement Sp of the braking operation member BP. At least one of SP (not shown) and an operating force sensor FP (not shown) for detecting the operating force Fp of the brake operating member BP is employed.

  The acceleration operation member (for example, accelerator pedal) AP is a member that the driver operates to accelerate the vehicle and run at a constant speed. By operating the acceleration operation member AP, the driving torque Tq for the wheel WH is adjusted, and a driving force is generated on the wheel WH. An acceleration operation amount sensor AA is provided to detect an operation amount Aa of the acceleration operation member (accelerator pedal) AP by the driver. For example, an acceleration operation displacement sensor that detects an operation displacement of the acceleration operation member AP is employed as the acceleration operation amount sensor AA.

  The vehicle is provided with a shift operation member (for example, a shift lever) HP for performing a shift operation. Further, a shift position sensor HA for detecting a shift position Ha of the speed change operation member HP is provided.

  A steering operation member (for example, a steering wheel) SW is a member operated by a driver to turn the vehicle. By operating the steering operation member SW, a steering angle Sa is given to a steered wheel (for example, the front wheel WHf), a lateral force is generated on the wheel WH, and the vehicle turns. A steering angle sensor SA is provided to detect a rotation angle (steering angle) Sa of the steering operation member SW.

  The wheel WH is provided with a wheel speed sensor VW that detects a wheel speed Vw that is a rotation speed of the wheel WH. The vehicle body includes a yaw rate sensor YR that detects the yaw rate Yr of the vehicle, a longitudinal acceleration sensor GX that detects an acceleration (longitudinal acceleration) Gx in the longitudinal direction of the vehicle, and an acceleration (lateral acceleration) Gy in the lateral direction of the vehicle. A lateral acceleration sensor GY for detecting is provided.

  A braking force is generated on the wheel WH by the braking device YB. The braking device YB includes a master cylinder CM, a brake caliper CP, a wheel cylinder CW, a rotating member KT, a friction material MS, a fluid unit HU, and a braking controller ECB. The master cylinder CM, the fluid unit HU, and the wheel cylinder CW are connected via a braking fluid path HW.

  During normal braking, the fluid unit HU is not operated, and the brake fluid BF is pumped from the master cylinder CM to the wheel cylinder CW in accordance with the operation of the braking operation member BP. Each wheel WH of the vehicle is provided with a brake caliper CP, a wheel cylinder CW, a rotating member KT, and a friction material MS. Specifically, a rotating member (brake disc) KT is fixed to the wheel WH, and a brake caliper CP is arranged. The brake caliper CP is provided with a wheel cylinder CW. By adjusting the hydraulic pressure (braking hydraulic pressure) Pw in the wheel cylinder CW, a braking torque Bq (as a result, a braking force) is generated on the wheel WH.

  The fluid unit HU is operated when anti-skid control, traction control, vehicle stabilization control, or the like is performed. By the operation of the fluid unit HU, the brake hydraulic pressure Pw is adjusted independently of the operation of the brake operation member BP and individually for each wheel. Thereby, the longitudinal force (braking / driving force) of each wheel WH is controlled independently and individually. The fluid unit HU includes an electric pump, a plurality of solenoid valves, and a low-pressure reservoir.

  The fluid unit HU (in particular, the electric motor of the electric pump and the solenoid valve) is controlled by the braking controller ECB. The braking operation amount Ba (Pm, Sp, Fp), the wheel speed Vw, the yaw rate Yr, the steering angle Sa, the longitudinal acceleration Gx, the lateral acceleration Gy, and the like are input to the controller ECB. In the controller ECB, for example, anti-skid control is executed so as to suppress excessive deceleration slip of the wheel WH (for example, wheel lock). Further, traction control is performed so as to suppress excessive acceleration slip (for example, wheel spin) of the wheel WH.

  The driving device YD generates a driving force on the driving wheels (wheels connected to the driving device YD) among the wheels WH. The drive device YD includes a power source EN (also referred to as a “drive source”), a transmission TM, and a drive controller ECD. The power source EN (for example, an internal combustion engine) is controlled by the drive controller ECD according to the acceleration operation amount Aa. The transmission TM (for example, an automatic transmission) is controlled by the drive controller ECD according to the shift position Ha. A torque converter TC is included between the power source EN and the transmission TM, and the output (power) Qa of the power source EN is transmitted to the transmission TM via the torque converter TC.

  The power source EN is provided with a throttle sensor TH for detecting a throttle opening Th, an injection amount sensor FI for detecting a fuel injection amount Fi, and a rotation speed sensor NE for detecting a driving rotation speed Ne. The drive controller ECD calculates the acceleration operation amount Aa (actual value), the throttle opening Th (actual value), the fuel injection amount Fi (actual value), and the driving speed Ne (actual value) of the power source EN. Output (power) Qa of power source EN is controlled. An electric motor for driving may be used as the power source EN. In this case, the amount of current (for example, current value) Im to the power source EN and the rotation speed Nm are detected. Then, the output Qa of the driving motor is controlled based on the acceleration operation amount Aa (actual value), the energization amount Im (actual value), and the motor speed Nm (actual value).

  The transmission TM is provided with a gear position sensor GP for detecting a gear ratio (gear position) Gp (actual value). The required speed ratio Gps (required value) of the automatic transmission TM is determined by the drive controller ECD based on the signals (Aa, Th, Fi, Ne, Im, Nm, etc.) related to the power source EN. For example, the required gear ratio Gps may be determined based on the vehicle body speed Vx. Then, in accordance with the required speed ratio Gps, the actual speed ratio Gp (actual value) is controlled to match the required value Gps (that is, the speed change operation of the transmission TM is performed). In addition, the drive controller ECD controls the lock-up mechanism LU of the torque converter TC. In response to the request signal Lus, the lock-up mechanism LU is released before the transmission TM starts shifting operation, and is locked after finishing the shifting operation. In other words, while the transmission TM is shifting, the lock-up mechanism LU is released. The engagement state of the lock-up mechanism LU can be detected as an actual engagement state (engagement signal) Lu. Therefore, the engagement state (disengagement or restriction) Hn of the lock-up mechanism LU is determined based on the engagement signals Lus (required value) and Lu (actual value). Alternatively, the engagement state Hn may be determined based on the speed ratios Gps, Gp. For example, when the gear ratios Gps (required value) and Gp (actual value) are changed from the first speed to the second speed, the lock-up mechanism LU is released during the speed change. The engagement state Hn is used for calculating the target output Qt in the traction control device TS.

  The drive controller ECD calculates and outputs the required throttle opening Ths, the fuel injection amount Fis, and the required gear ratio Gps based on the acceleration operation amount Aa. The required throttle opening Ths, the fuel injection amount Fis, and the required gear ratio Gps are target values of the throttle opening Th, the fuel injection amount Fi, and the gear ratio Gp. The actual throttle opening Th, the actual fuel injection amount Fi, and the actual gear ratio Gp are controlled so as to match the required throttle opening Ths, the required fuel injection amount Fis, and the required gear ratio Gps. When the power source EN is an electric motor, the required energization amount (target value) Ims is calculated based on the acceleration operation amount Aa, and control is performed so that the actual energization amount Im matches the target value Ims. You.

  The drive controller ECD and the brake controller ECB share information (computed values, sensor values, etc.) via the communication bus BS. For example, traction control, vehicle stabilization control, and the like are executed by the braking controller ECB. In response to an instruction signal (target output Qt) from the brake controller ECB, the output of the power source EN is reduced by the drive controller ECD. A controller that shares information through the communication bus BS is called an “ECU (electronic control unit)”. That is, the controller ECU includes at least the drive controller ECD and the brake controller ECB.

<Power transmission via torque converter TC>
With reference to the schematic diagram of FIG. 2, transmission of output (power) Qa of power source EN via torque converter TC will be described. The torque converter TC is provided in a multi-stage automatic transmission or a continuously variable transmission (so-called CVT). Specifically, torque converter TC is provided between power source EN (input shaft JI of torque converter TC) and transmission TM (output shaft JO of torque converter TC). The transmission TM is connected to drive wheels (front wheels) WHf via a drive shaft DS. Therefore, the output (power) Qa of the power source EN is transmitted to the drive wheels WHf as the drive torque Tq via the torque converter TC, the transmission TM, and the drive shaft DS.

  The torque converter TC includes a pump impeller PI, a turbine runner TR, a stator SR, and a lockup mechanism LU. The pump impeller PI, the turbine runner TR, and the stator SR are impellers. Pump impeller PI is connected to input shaft JI (output shaft of a power source) of torque converter TC. Turbine runner TR is connected to output shaft JO of torque converter TC. The working fluid is filled between the pump impeller PI and the turbine runner TR, and power is transmitted via the fluid. A stator SR is provided between the pump impeller PI and the turbine runner TR, and the output torque of the turbine runner TR is amplified with respect to the input torque from the pump impeller PI. This amplification effect decreases as the speed ratio of the torque converter TC (the rotation speed of the turbine runner TR with respect to the rotation speed of the pump impeller PI) increases. That is, the torque converter TC amplifies the torque in a region where the output rotation speed is smaller than the input rotation speed, and functions as a mere fluid connection when the output rotation speed is increased to a certain degree or more. Lock-up mechanism LU is provided to reduce power transmission loss in a region where the amplifying effect of torque converter TC is reduced.

  The lock-up mechanism LU of the torque converter TC is controlled by the drive controller ECD. The power transmission path from the output Qa of the power source EN to the drive torque Tq is switched depending on the engagement state of the lock-up mechanism LU. That is, in the power transmission between the input shaft JI and the output shaft JO of the torque converter TC, "the state in which the engagement of the lock-up mechanism LU is restrained and mechanically fixed (direct connection state)" and "the lock-up mechanism LU" The state in which the engagement of the mechanism LU is released and the power is transmitted via the working fluid (release state) is switched. In the directly connected state, power Qa is transmitted to transmission TM in the order of “JI → LU → JO”. On the other hand, in the released state, power Qa is transmitted to transmission TM in the order of “JI → PI → TR → JO”.

  When the lock-up mechanism LU is connected (restricted), the power source EN and the transmission TM are directly connected without passing through the fluid. As a result, power Qa is efficiently transmitted to drive wheels WHf. For example, when the power Qa is reduced by the traction control, the driving torque Tq is immediately reduced with a high response.

  For example, when the vehicle starts, creeps, or shifts, it is necessary to release the lock-up mechanism LU. When the lock-up mechanism LU is released (released), power is transmitted from the power source EN to the transmission TM via the fluid, so that power loss occurs in power transmission of the power Qa to the drive wheels WHf. . Therefore, when the power Qa is reduced by the traction control, the driving torque Tq is delayed in time due to a slip in the torque converter TC (difference in rotation speed between the pump impeller PI and the turbine runner TR). Is reduced. Note that "creep running" means that the vehicle runs with the power source EN idling even when the acceleration operation member AP is not operated.

<Overview of Traction Control Device TS>
An outline of the traction control device TS will be described with reference to a functional block diagram of FIG. The traction control device TS includes “processing for controlling the power source (drive source) EN to control the drive torque Tq of the drive wheel WHf (front wheel)” and “processing for controlling the fluid unit HU to drive the drive wheel WHf. Of controlling the braking torque Bq. The traction control device TS includes a vehicle speed calculation block VX, a drive reference speed calculation block VK, a drive torque control block QT, a braking reference speed calculation block VS, and a braking torque control block BT.

  In the vehicle speed calculation block VX, the vehicle speed Vx is calculated based on the wheel speed Vw. For example, the vehicle speed Vx is calculated based on the wheel speed Vwr of the driven wheel WHr. The driven wheel WHr is a wheel to which power from the driving device YD is not transmitted, and corresponds to a rear wheel WHr in a front-wheel-drive vehicle.

  The drive reference speed calculation block VK calculates the drive reference speed Vk based on the vehicle speed Vx. The drive reference speed Vk is a wheel speed serving as a reference when the output Qa of the power source EN is controlled (during drive torque control). For example, the reference speed Vk is determined by adding the predetermined speed vk to the vehicle speed Vx (that is, “Vk = Vx + vk”). Here, the predetermined speed vk is a predetermined value (constant) set in advance.

  In the drive torque control block QT, a target output Qt is calculated based on the drive reference speed Vk and the drive wheel speed Vwf. The target output Qt is a target value (limit value) for limiting the actual output (power) Qa of the power source EN. Therefore, when the actual output Qa is equal to or less than the target output Qt, the output Qa of the power source EN is not limited. On the other hand, when the actual output Qa is larger than the target output Qt, the throttle opening Th and the fuel injection amount Fi (or the motor current amount Im) are reduced so that the output Qa becomes equal to or less than the target output Qt. Output Qa is reduced. As a result, the drive torque Tq of the drive wheel WHf is reduced, and excessive acceleration slip Sw is suppressed. Details of the drive torque control block QT will be described later.

  In a reference braking speed calculation block VS, a reference braking speed Vs is calculated based on the vehicle speed Vx. The braking reference speed Vs is a wheel speed serving as a reference when the braking hydraulic pressure Pw is controlled (during braking torque control). For example, the predetermined speed vs is added to the vehicle speed Vx to determine the reference speed Vs (that is, "Vs = Vx + vs"). Here, the predetermined speed vs is a predetermined value (constant) set in advance, and has a relationship of “vs> vk”.

  In the braking torque control block BT, the fluid unit HU is controlled based on the braking reference speed Vs and the driving wheel speed Vwf. Specifically, the brake fluid pressure Pw is adjusted such that the drive wheel speed Vwf approaches and matches the brake reference speed Vs. Note that the predetermined speed vs is set to a value higher than the predetermined speed vk, so that the braking reference speed Vs is higher than the driving reference speed Vk. Therefore, in the traction control, first, the driving torque control is executed. When the drive wheel speed Vwf does not increase or does not sufficiently decrease despite the output Qa being reduced by the drive torque control, the acceleration slip Sw of the drive wheel WHf is quickly reduced by the braking torque control block BT. Thus, the braking hydraulic pressure Pwf is increased (that is, the braking torque Bq of the drive wheel WHf is increased).

<First Processing Example of Drive Torque Control in Traction Control Device TS>
A first processing example of drive torque control will be described with reference to a functional block diagram of FIG. By the driving torque control, the output (power) Qa of the power source EN is limited so as to suppress the excessive acceleration slip Sw of the driving wheel WHf (the wheel to which the output Qa is transmitted), and the driving torque Tq is reduced. The drive torque control includes a vehicle body speed calculation block VX, a drive reference speed calculation block VK, a drive wheel average speed calculation block VH, a proportional / integral control block QS, an engagement state determination block HN, and an adjustment processing block CQ. You.

  In the vehicle speed calculation block VX, the vehicle speed Vx is calculated based on the wheel speed Vw (particularly, the wheel speed Vwr of the driven wheel WHr). In the drive reference speed calculation block VK, a predetermined speed vk (for example, a constant) is added to the vehicle body speed Vx to determine a drive reference speed Vk (also simply referred to as “reference speed Vk”).

  In a driving wheel average speed calculation block VH, a driving wheel average speed Vh (also simply referred to as “average speed Vh”) is calculated based on the wheel speed Vwf of the driving wheel WHf. The drive wheel WHf is a wheel to which power from the drive device YD is transmitted, and corresponds to the front wheel WHf in a front-wheel drive vehicle. The average speed Vh is an average value of the two drive wheel speeds Vwf. The acceleration slip Sw is calculated based on the reference speed Vk and the average speed Vh. Specifically, the acceleration slip Sw is determined by subtracting the reference speed Vk from the average speed Vh (that is, “Sw = Vh−Vk”).

  In the proportional / integral control block QS (corresponding to the “calculating section”), the proportional / integral control is executed based on the acceleration slip Sw. Specifically, when the acceleration slip Sw becomes equal to or more than the predetermined value sz, the execution of the traction control is started. Then, the acceleration slip Sw is multiplied by the proportional gain Kp (that is, “Kp × Sw”). Further, the time integral of the acceleration slip Sw is multiplied by the integral gain Ki (that is, “KiｉSw”). Further, these are added to calculate the required output Qs (that is, “Qs = Kp × Sw + Ki × ∫Sw”). The required output Qs is a target value (limit value) for limiting the actual output Qa. The execution of the traction control may be started when the required output Qs becomes equal to or more than the predetermined value qs. The predetermined values sz and qs are preset constants.

  In the engagement state determination block HN (corresponding to a “determination section”), the engagement state of the lock-up mechanism LU is determined based on at least one of the instruction signal Lu and the actual state Lu in the lock-up mechanism LU. Is determined. That is, "the lock-up mechanism LU is restrained, and the input shaft JI (the output shaft of the power source EN) and the output shaft JO (the input shaft of the transmission TM) are in a directly connected state (directly connected state) in the torque converter TC. Or whether the lock-up mechanism LU is released and the power is transmitted between the input shaft JI and the output shaft JO through the fluid in the torque converter TC (released state). Then, the determination result Hn is output from the engagement state determination block HN. For example, the determination flag Fh is adopted as the engagement state Hn, and “Fh = 0” is determined in the direct connection state, and “Fh = 1” is determined in the release state.

  In an adjustment processing block CQ (corresponding to an “adjustment section”), the required output Qs (also referred to as “required torque”) is adjusted based on the engagement state Hn (determination result), and the target output Qt is calculated. Here, the target output Qt (also referred to as “target torque”) is a final target value of the limited torque in the drive torque control. In the case of “Qa ≦ Qt”, no limitation is performed and the actual output Qa is not reduced. In the case of "Qa> Qt", the power source EN is controlled so that the actual output Qa decreases to the target output Qt (reduction of the throttle opening Th, the fuel injection amount Fi, and the motor energization amount Im).

  Specifically, in the adjustment processing block CQ, when the engagement state Hn is in the constrained state (coupled state) (for example, when “Fh = 0”), the required output Qs is not adjusted and the target output Qt (ie, “Qt = Qs”). On the other hand, when the engagement state Hn is in the release state (release state) (for example, in the case of “Fh = 1”), the required output Qs is reduced by the adjustment output Qh (also referred to as “adjustment torque”). The target output Qt is determined (that is, “Qt = Qs−Qh”). That is, when the engagement state of the lockup mechanism LU is changed from the restrained state to the released state, the target output Qt is rapidly reduced from “Qs” to “Qs−Qh” by the adjustment output Qh. You. Here, the adjustment output Qh based on the engagement state Hn is for reducing and adjusting the required output Qs to determine the final target output Qt.

  For example, the adjustment output Qh based on the engagement state Hn is set as a predetermined torque qh. The predetermined torque qh is a constant set in advance. Further, the adjustment output Qh can be determined based on the slip state sv. The slip state sv is the value of the acceleration slip Sw at the time when the determination flag Fh transitions from “0 (coupled state)” to “1 (released state)” (a corresponding calculation cycle). As shown in the calculation map Zv of the blowing section, the calculation is performed such that the adjustment output Qh increases as the slip state sv increases. The fact that the slip state sv is large is based on the fact that the target output Qt should be made smaller.

  In the adjustment processing block CQ, the adjustment output Qh is calculated based on at least one of the required speed ratio Gps and the actual speed ratio Gp. Specifically, according to the gear ratios Gps (required value) and Gp (actual value), the time (operation cycle) at the time of transition from “Fh = 0 (restricted state)” to “Fh = 1 (released state)” The reduction ratio gs is stored. Then, the adjustment output Qh is determined based on the reduction ratio gs. For example, in a multi-stage automatic transmission, when the speed is changed from the first speed (first stage, also referred to as “low gear”) to the second speed (second stage), the reduction ratio gs corresponds to the first speed. Reduction ratio. The adjustment output Qh is calculated so as to increase as the reduction ratio gs increases, as shown in a calculation map Zg of the blowing section. The fact that the reduction gear ratio gs is large is based on the fact that the power transmission delay in the torque converter TC has a large effect. Therefore, when shifting from the first speed (for example, when the vehicle starts), the adjustment output Qh is determined to be larger than when shifting from the second speed, and as a result, the target output Qt is made smaller. .

  In the traction control device TS applied to the vehicle provided with the torque converter TC having the lock-up mechanism LU, the decrease in the driving torque Tq due to the decrease in the power Qa depends on the engagement state of the lock-up mechanism LU. When the lock-up mechanism LU is restrained (fastened), the power Qa is transmitted directly to the transmission TM without passing through the fluid in the torque converter TC, so that the change in the power Qa is driven without time delay. It is transmitted as a change in torque Tq. On the other hand, when the lock-up mechanism LU is released, the power Qa is transmitted to the transmission TM via the fluid in the torque converter TC. Delay can occur.

  In the traction control device TS, a required output Qs (required value) for limiting the power (output of the power source EN) Qa is calculated based on the acceleration slip Sw. The engagement state Hn of the lock-up mechanism LU is determined based on at least one of the instruction signal (instruction state) Lus and the actual state Lu in the engaged state. When the lock-up mechanism LU is released based on the engagement state Hn, the required output Qs is reduced and adjusted by the adjustment output Qh so that the required output Qs becomes smaller than when the lock-up mechanism LU is restrained. , The final target output Qt is determined. When the release of the lock-up mechanism LU is started, the required output Qs is greatly reduced (rapidly reduced) by the adjustment output Qh (for example, “= qh”). Thereby, the influence of the power transmission path in torque converter TC is compensated, and suitable traction control can be performed. As a result, excessive acceleration slip Sw of the drive wheel WHf is quickly suppressed, and the convergence of the drive wheel WHf is improved.

  Further, the greater the reduction ratio of the transmission TM, the greater the effect of the torque converter TC. Therefore, the required output Qs is reduced and adjusted based on at least one of the required speed ratio Gps and the actual speed ratio Gp. Specifically, when the lockup mechanism LU is released (for example, during shifting of the transmission TM), the calculation is performed such that the larger the reduction ratio, the larger the adjustment output Qh. As a result, the required value Qs is reduced and adjusted to be small, and the final target output Qt is determined. For example, based on the reduction ratio gs at the time when the lock-up mechanism LU transitions from the restrained state to the released state (operation cycle), the required output Qs is adjusted to decrease as the reduction gear ratio gs increases. Since the required output Qs is reduced and adjusted based on the speed reduction ratio in the speed change operation of the transmission TM, more appropriate traction control can be performed.

  The adjustment for decreasing the required output Qs can be executed only when the vehicle starts. When the vehicle is stopped, the lockup mechanism LU is in the released state. Therefore, when the vehicle starts, the lock-up mechanism LU is in the released state, and the reduction ratio of the transmission TM is the maximum (that is, the first speed of the multi-stage automatic transmission). On the other hand, when the speed ratios Gps and Gp are the second speed or higher, it is based on the fact that the torque converter TC does not significantly affect the power transmission time delay during the speed change. Since the situation where the required output Qs is reduced and adjusted is limited, the reliability of the control can be improved.

<Second processing example of drive torque control of traction control device TS>
A second processing example of drive torque control will be described with reference to the functional block diagram of FIG. In the second processing example, a longitudinal acceleration calculation block GA and a decrease amount calculation block SG are added to the first processing example.

  In the acceleration calculation block GA, the longitudinal acceleration Ga is calculated based on the vehicle speed Vx. The longitudinal acceleration Ga is the actual longitudinal acceleration (actual acceleration) of the vehicle (vehicle body). Specifically, the vehicle speed Vx is time-differentiated at a predetermined calculation cycle (for example, every several milliseconds), and the longitudinal acceleration Ga is calculated. Further, the longitudinal acceleration Gx detected by the longitudinal acceleration sensor GX may be employed as the longitudinal acceleration Ga. Further, both the longitudinal acceleration Gx (detected value) and the longitudinal acceleration Ga (calculated value) may be used as the longitudinal acceleration Ga so as to improve the robustness.

  In the decrease amount calculation block SG, the integrated amount Sg is calculated based on the longitudinal acceleration Ga. The integrated amount Sg is a decrease amount from the peak value of the longitudinal acceleration Ga. Specifically, in the decrease amount calculation block SG, in the calculation cycle of the controller ECU, the current longitudinal acceleration Ga [n] (from the previous longitudinal acceleration Ga [n−1] (also referred to as “previous value”) ( The amount of decrease Gg [n] of the “current value” is calculated. Here, "n" at the end of the symbol indicates the operation cycle, where "n" indicates the current (current) operation cycle and "n-1" indicates the immediately previous operation cycle (previous), respectively. Represent.

  In the reduction amount calculation block SG, the reduction amount Gg [n] is sequentially accumulated for each calculation cycle. The reduced amount 減少 Gg [n] integrated up to the current calculation cycle “n” is referred to as “integrated amount Sg [n]” (that is, “Sg [n] = ΣGg [n]”). That is, the current reduction amount Gg [n] is added to the integration amount Sg [n-1] up to the previous calculation cycle “n−1”, and the current integration amount Sg [n] is determined.

  Further, in the decrease amount calculation block SG, when the current longitudinal acceleration (current value) Ga [n] increases from the previous longitudinal acceleration (previous value) Ga [n-1], the current integrated amount Sg [ n] is reduced to a predetermined ratio rs of the previous integrated amount Sg [n−1] (that is, “Sg [n] = rs × Sg [n−1]”). Here, the predetermined ratio rs is a preset constant. For example, the predetermined ratio rs is set to “0%”. In this case, when the longitudinal acceleration Ga increases, the integrated value Sg is reset to “0”.

  In addition, the decrease amount calculation block SG includes a timer (time counter). This timer calculates the continuation of time. For the first time after the traction control is started, the continuation time is counted from the time when the longitudinal acceleration Ga decreases (the corresponding calculation cycle). The integrated value Sg is reset to “0” when a predetermined time tx has elapsed from the time when the state where the integrated value Sg is larger than the predetermined amount sx is satisfied for the first time. Here, the predetermined amount sx and the predetermined time tx are constants set in advance.

  In the adjustment processing block CQ (adjustment unit), the required output Qs is adjusted based on the integrated amount Sg in addition to the engagement state Hn. Specifically, when the integrated amount Sg [n] exceeds the predetermined amount sx, the required output Qs is reduced by the adjustment output Qg based on the integrated amount Sg, and the target output Qt is determined. That is, in the lock-up mechanism LU, "Qt = Qs-Qg" is calculated in the restricted state, and "Qt = Qs-Qh-Qg" is calculated in the released state. Here, the predetermined amount sx is a threshold value for determining “whether the required output Qs is adjusted to be reduced or not (ie, whether to calculate the adjusted output Qg or not)”, and is set in advance. This is a predetermined constant.

  For example, the adjustment output Qg based on the integrated amount Sg is set as a predetermined torque qg. The predetermined torque qg is a preset constant. Further, the adjustment output Qg can be determined based on at least one of the slip state sw and the duration time tg. The slip state sw is a value of the acceleration slip Sw at the time when “Sg> sx” is satisfied (a corresponding calculation cycle). As shown in the calculation map Zs of the blowing section, the calculation is performed such that the adjustment output Qg increases as the slip state sw increases. The fact that the slip state sw is large is based on the fact that the target output target output Qt should be made smaller.

  The continuation time tg is a time from the time when the increase of the integrated amount Sg is started to the time when “Sg> sx” is satisfied. As shown in the calculation map Zt, the adjustment output Qg is calculated so as to be smaller as the duration tg is longer. The long duration tg is based on the fact that the longitudinal acceleration does not decrease so much and the acceleration slip Sw does not increase rapidly.

  In the traction control device TS, the actual longitudinal acceleration Ga is calculated. Then, the amount of decrease Gg of the longitudinal acceleration Ga (the amount of decrease Gg [n] in the present value Ga [n] from the previous value Ga [n-1]) is calculated in each calculation cycle. This reduction amount Gg is sequentially integrated, and determined as an integration amount Sg (= ΣGg). In other words, the total of the reduction amounts Gg from the time when the longitudinal acceleration Ga exhibits the peak value and the decrease in the longitudinal acceleration Ga is started (ie, the calculation cycle in which the decrease in the longitudinal acceleration Ga is determined) is the integrated amount Sg It is. In the output adjustment process, if the integrated amount Sg is equal to or smaller than the predetermined amount sx, the required output Qs is not adjusted depending on the integrated amount Sg. On the other hand, when the integrated amount Sg becomes larger than the predetermined amount sx, the amount of the adjustment output Qg (adjustment torque) is reduced from the required output Qs (requested torque), and the target output Qt (target torque) is rapidly reduced. (Ie, "Qt = Qs-Qg" or "Qt = Qs-Qh-Qg").

  The adjustment for decreasing the target output Qt is ended when the increase in the longitudinal acceleration Ga is started. Alternatively, the decrease adjustment can be ended when the integrated value Sg becomes equal to or less than the predetermined amount sx. Further, the decrease adjustment may be ended when a predetermined time tx (a preset constant) has elapsed from the time when “Sg> sx” is satisfied for the first time. At the end of the decrease adjustment, the adjustment output Qg is not immediately set to “0”, but is gradually reduced (with the time change gradient limited) toward “0”. The target output Qt is smoothly increased to the required output Qs so that a sudden change in the output Qa is suppressed.

  In the traction control device TS, the target output Qt is significantly reduced (that is, sharply reduced) when the longitudinal acceleration Ga is continuously reduced during vehicle acceleration. That is, the friction coefficient of the road surface changes from a high state to a low state based on the integrated amount Sg determined according to the state quantity over a certain calculation cycle, not the state quantity determined for each calculation cycle. Is properly determined. In other words, since the road surface friction state is determined by using not only the current state quantity but also the past state quantity, the complexity of the control due to the fluctuation of the control amount of the traction control is suppressed. Then, based on the determination result, the actual output Qa is reduced to a value suitable for the road surface friction coefficient. Excessive acceleration slip Sw of the drive wheel WHf is quickly suppressed, and the convergence of the drive wheel WHf is improved. As a result, the driver's feeling of acceleration of the vehicle is improved.

<Process in the decrease amount calculation block SG>
With reference to the time series diagram of FIG. 6, the processing in the decrease amount calculation block SG (reduction amount calculation unit) will be described. The symbols in parentheses at the end of each symbol indicate at what point (corresponding operation cycle) it is. For example, “Ga [t7]” indicates the longitudinal acceleration Ga at the time point t7.

  Until time t4, the longitudinal acceleration Ga is gradually increasing. Therefore, “Gg = 0” is calculated, and “Sg = 0”. At time t5, the longitudinal acceleration Ga [t5] decreases from the longitudinal acceleration Ga [t4]. Therefore, at time t5, "Gg [t5] = Ga [t5] -Ga [t4]" is calculated. At time t5, “Sg [t5] = 0”, so “Sg [t5] = Gg [t5]” is calculated.

  At time t6, the longitudinal acceleration Ga [t6] decreases from the longitudinal acceleration Ga [t5]. At time t5, "Gg [t6] = Ga [t6] -Ga [t5]" is calculated. At time t6, since "Sg [t5] = Gg [t5]", "Sg [t6] = Sg [t5] + Gg [t6]" is calculated.

  Similar calculations are repeated for each calculation cycle. That is, the amount of decrease Gg [n] of the current longitudinal acceleration Ga [n] from the previous longitudinal acceleration Ga [n-1] is calculated. Then, the current reduction amount Gg [n] is added to the previous integration amount Sg [n-1], and the current integration amount Sg [n] is determined. At time point t8, the integrated amount Sg [t8] is calculated as “Sg [t7] + Gg [t8]”. Until time t8, since the integrated amount Sg is equal to or smaller than the predetermined amount sx, the adjustment of the required output Qs is not performed. In the restrained state, the required output Qs is determined as it is as the target output Qt. Qt = Qs-Qh "is determined.

  At time point t9, the integrated amount Sg [t9] is calculated as “Sg [t8] + Gg [t9]”. At time t9, since the integrated amount Sg exceeds the predetermined amount sx, the regulated output Qg is reduced from the required output Qs, and the target output Qt is determined (that is, “Qt = Qs−Qg” or “Qt”). = Qs-Qh-Qg "). As a result, the target output Qt is significantly reduced (ie, sharply reduced). When the longitudinal acceleration Ga continues to decrease, the state of “Sg> sx” is maintained, so the state of “Qt = Qs−Qg” or “Qt = Qs−Qh−Qg” (decrease adjustment) is continued. You.

  At the time point t15, the longitudinal acceleration Ga [t15] increases more than the longitudinal acceleration Ga [t14]. In this case, the integrated amount Sg [t15] is reduced to a predetermined ratio rs (that is, Sg [t15] = rs × Sg [t14]). For example, when “rs = 0%” is set, the integrated amount Sg [t15] is reset to “0”. When “rs = 50%” is set, the integrated amount Sg [t15] is determined to be “１ ／” of the integrated amount Sg [t14] (see the characteristic indicated by the broken line). Thereafter, when the longitudinal acceleration Ga decreases, the integrated amount Sg increases. However, when the longitudinal acceleration Ga increases, the integrated amount Sg repeatedly decreases.

  As conditions for terminating the decrease adjustment of the target output Qt, “the longitudinal acceleration Ga increases”, “the integrated amount Sg is equal to or less than the threshold value sx”, and “the duration of the decrease adjustment is a predetermined time tz (a preset constant)” At least one of the above is adopted. At time t15, the “increase of the longitudinal acceleration Ga” or the “condition of“ Sg ≦ sx ”due to the decrease of the integrated amount Sg” is satisfied, and the decrease adjustment of the target output Qt is ended. When the output adjustment is completed, the adjusted output Qg is gradually reduced and the target output Qt is gradually increased so as to avoid a sudden change in the actual output Qa.

<Action / Effect>
The operation and effect of the traction control device TS according to the present invention will be summarized. Traction control device TS is applied to a vehicle including a torque converter TC having a lock-up mechanism LU in a power transmission path between power source EN and transmission TM. The traction control device TS limits the output Qa so as to suppress the excessive acceleration slip Sw of the drive wheel WHf to which the output Qa of the power source EN is transmitted. The traction control device TS includes a traction control proportional / integral control block (request output calculation block) QS (calculation unit), an engagement state determination block HN (determination unit), and an adjustment processing block CQ (adjustment unit). Be composed.

  In the required output calculation block QS, a required output Qs (required value) for limiting the output Qa is calculated based on the acceleration slip Sw. In the engagement state determination block HN, the engagement state Hn of the lock-up mechanism LU is determined. In the adjustment processing block CQ, the required output Qs is reduced and adjusted based on the engagement state Hn, and the target output Qt is determined. When the lockup mechanism LU is released (disengaged), the required output Qs is adjusted to be smaller than when the lockup mechanism LU is restrained (engaged). For example, when the transmission TM shifts, the adjustment output Qh is reduced from the required output Qs at the time when the release state is started based on the engagement state Hn, and the target output Qt is rapidly reduced. The drive controller ECD controls the actual output Qa to approach and match the target output Qt, so that the output Qa is rapidly reduced.

  In the restrained state, the power source EN and the transmission TM are mechanically directly connected, but in the released state, the power Qa of the power source EN is transmitted to the transmission TM via the fluid of the torque converter TC. You. For this reason, even if the power Qa is reduced, a time delay may occur before the reduction of the driving torque Tq of the driving wheel WHf is started. In the release state, the required output Qs is adjusted to decrease so that the final target output Qt becomes smaller. Therefore, the time delay is compensated, and the excessive acceleration slip Sw of the drive wheel WHf is quickly suppressed.

  The greater the reduction ratio of the transmission TM, the greater the effect of the time delay due to the released state of the torque converter TC. Therefore, in the adjustment processing block CQ, based on the speed reduction ratio gs at the time when the transmission TM starts shifting, a calculation is performed such that the required value Qs decreases as the reduction ratio gs increases. Thereby, the adjustment of the required output Qs according to the reduction ratio (for example, the shift speed) can be achieved. For example, in the adjustment processing block CQ, the reduction adjustment of the required output Qs is executed only when the vehicle starts. When the vehicle is stopped, the lock-up mechanism LU is in the released state. Therefore, when the operation of the acceleration operation member AP is increased in the first gear (low gear), the required output Qs is already reduced by the adjustment output Qh. Have been. Since the conditions for decreasing the required output Qs are limited, the reliability of control execution can be improved.

  Further, the traction control device TS may be provided with a longitudinal acceleration calculation block GA and a decrease amount calculation block SG. The longitudinal acceleration calculation block GA calculates the longitudinal acceleration Ga at a predetermined calculation cycle. For example, in the longitudinal acceleration calculation block GA, the longitudinal acceleration Ga is calculated by differentiating the time based on the vehicle speed Vx corresponding to the wheel speed Vw. Further, based on the longitudinal acceleration Gx (detected value) detected by the longitudinal acceleration sensor GX, the longitudinal acceleration Gx can be filtered to determine the longitudinal acceleration Ga. In the decrease amount calculation block SG, the previous longitudinal acceleration Ga [n-1] (previous value) is stored in the calculation cycle. In the calculation cycle, the current longitudinal acceleration Ga [n] (current value) is obtained. Then, the amount of reduction Gg [n] of the current value Ga [n] from the previous value Ga [n-1] is calculated. The reduction amount Gg [n] is integrated for each calculation cycle to determine the integration amount Sg [n]. In the adjustment processing block CQ, when the integrated amount Sg [n] exceeds a predetermined amount sx (a predetermined threshold value for determination), the output Qa of the power source EN is reduced. Specifically, the adjustment output Qg determined according to the integrated amount Sg is subtracted from the required output Qs calculated based on the acceleration slip Sw, and the target output Qt is sharply reduced. The drive controller ECD controls the actual output Qa to approach and match the target output Qt, so that the output Qa is rapidly reduced.

  Based on the integrated amount Sg integrated over a plurality of calculation cycles, it is determined that the road surface friction coefficient has changed from a high state to a low state, and the actual output Qa is reduced to a value suitable for the road surface friction coefficient. Is reduced. If the traveling road surface changes from the high friction state to the low friction state while the transmission TM is shifting (when the lockup mechanism LU is in the released state), the target output Qt is calculated to a smaller value. (Ie, “Qt = Qs−Qh−Qg”). Thereby, suitable traction control according to the engagement state of the lockup mechanism LU and the road surface friction state is achieved, and a good feeling of acceleration for the driver can be achieved.

<Other embodiments>
Hereinafter, other embodiments will be described. In other embodiments, the same effects as above can be obtained. In the above embodiment, the traction control device TS is applied to a front-wheel drive vehicle in which the drive wheels connected to the power source EN are the front wheels WHf. The traction control device TS can be applied to a rear-wheel drive vehicle. In this case, the driving wheel is the rear wheel WHr, and the driven wheel is the front wheel WHf.

  The traction control device TS may be applied to a four-wheel drive vehicle. In a four-wheel drive vehicle, it is preferable that a detected longitudinal acceleration Gx (a detected value of the longitudinal acceleration sensor GX) be employed as the longitudinal acceleration Ga. When the four wheels are drive wheels, it is based on the fact that all the wheels WH include the acceleration slip Sw.

TS: Traction control device, EN: Power source, TM: Transmission, TC: Torque converter, LU: Lock-up mechanism, ECU: Controller, ECB: Braking controller, ECD: Drive controller, VW: Wheel speed sensor, GX: Front and rear Acceleration sensor, AA: acceleration operation amount sensor, QS: required output calculation block (proportional / integral control block), HN: engagement state determination block, GA: longitudinal acceleration calculation block, SG: reduction amount calculation block, CQ: adjustment processing Block, Vw: wheel speed, Vx: body speed, Vk: reference speed (drive wheel), Hn: engagement state, Ga: longitudinal acceleration, Sw: acceleration slip (drive wheel), Gg: decrease, Sg: integrated amount , Qh: adjustment output based on the engagement state, Qg: adjustment output based on the integrated amount, Qs: required output, Qt: target output, Qa: actual Force.

Claims (2)

Applied to a vehicle equipped with a torque converter having a lock-up mechanism in a power transmission path between a power source and a transmission,
A traction control device for a vehicle that limits the output, so as to suppress excessive acceleration slip of a drive wheel to which the output of the power source is transmitted,
A calculating unit that calculates a request value for limiting the output based on the acceleration slip;
A determining unit that determines an engagement state of the lock-up mechanism;
Based on the engagement state, when the lock-up mechanism is released, than when the lock-up mechanism is constrained, an adjustment unit that reduces and adjusts the required value to be smaller,
A traction control device for a vehicle, comprising: The traction control device for a vehicle according to claim 1,
The traction control device for a vehicle, wherein the adjustment unit performs the decrease adjustment of the request value only when the vehicle starts moving.