JP4830680B2 - Brake control device for vehicle - Google Patents

Description

  The present invention relates to a vehicle brake control apparatus including a motor generator and an automatic transmission.

  Conventionally, an automatic transmission (hereinafter referred to as “AT”) is interposed between a driving wheel and a motor generator (hereinafter referred to as “MG”). By changing the gear position of the automatic transmission AT according to the vehicle speed, the motor generator MG 2. Description of the Related Art An automobile power output device that outputs power to drive wheels in accordance with vehicle speed is known. In this device, braking force can be output by regenerative control of motor generator MG during braking. That is, a braking force (regenerative brake torque) can be output from the motor generator MG to the drive wheels via the automatic transmission AT, and regenerative cooperative brake control is performed together with the friction brake control.

In this type of power output apparatus, if a shift is executed while the regenerative brake torque is being output, a shift shock occurs. In addition, heat may be generated in a clutch or a brake necessary for shifting. In order to suppress these shift shocks and the like, the prior art, for example, the device described in Patent Document 1, starts a shift after switching a braking force source from a regenerative brake to a friction brake when a shift request is made during braking, After the shift is completed, the configuration is switched from the friction brake to the regenerative brake again. During this switching, the total brake torque including the regenerative brake torque and the friction brake torque is controlled to be a required value, that is, the target brake torque.
JP 2005-329926 A

  However, when the vehicle deceleration is large, the second shift request may be made during the switching from the friction brake to the regenerative brake after the completion of the first shift. In this case, in the above prior art, switching from the regenerative brake to the friction brake is performed again. Therefore, when looking at the friction brake generating the brake torque by hydraulic pressure, the pressure reduction state (reduction force) is changed to the pressure increase state (power increase). It will change suddenly. For this reason, a delay in pressure increase of the friction brake occurs, and the friction brake torque temporarily decreases by this amount. Therefore, the total brake torque is also temporarily reduced by the decrease in the friction brake torque. In other words, depending on the length of time until the second shift request is made after the completion of the first shift, a response delay of the friction brake occurs, and the vehicle deceleration is temporarily insufficient with respect to the driver's request. There was a problem.

  The present invention has been made paying attention to the above-described problem. In a vehicle having an automatic transmission and performing regenerative cooperative brake control, after completion of the first shift during braking, until the second shift is started. An object of the present invention is to provide a vehicle brake control device that can satisfy the vehicle deceleration required by the driver by preventing a delay in pressure increase of the friction brake between the two.

  In order to achieve the above object, according to the present invention, there is provided an automatic transmission that is interposed between a motor generator and drive wheels and that changes the output rotation of the motor generator by at least a second speed and transmits the output rotation to the drive wheels. A shift control means for controlling a shift by the automatic transmission, a friction brake for generating a friction brake torque on the drive wheel by a hydraulically controlled actuator, and a regenerative torque generated by the motor generator for output to the drive wheel. Regenerative brake torque control means for controlling the regenerative brake torque, friction brake torque control means for controlling the friction brake torque, and target brake of the drive wheel that achieves the target deceleration of the vehicle according to the driver's brake operation Target brake torque calculating means for calculating torque, and the regenerative brake torque is When shifting is requested during output to the driving wheel, the ratio of the target value of the regenerative brake torque to the target brake torque is decreased and the ratio of the target value of the friction brake torque is increased, thereby generating the regenerative brake torque. A first control that replaces the friction brake torque with the second control, a second control that starts the shift after the end of the first control, and a ratio of the regenerative brake torque target value to the target brake torque after the shift ends. In a vehicle brake control device comprising: a regenerative cooperative brake control means that performs a third control that reduces the ratio of the friction brake torque target value and replaces the friction brake torque with the regenerative brake torque. Next, a request for the second shift during the third control after the end of the shift is predicted Shift request prediction means is provided, and the regenerative cooperative brake control means predicts that the first control is started when the second shift is requested during the third control after the end of the first shift. In the case where the friction brake torque target value is switched from a decrease to an increase, vehicle friction reduction lowering prevention means for suppressing fluctuations in the amount of change in the friction brake torque target value per hour when the friction brake torque target value is switched is provided.

  Therefore, in the vehicle brake control device of the present invention, the friction brake pressure is increased by controlling the change in the state of the friction brake pressure between the completion of the first shift during braking and the start of the second shift. The pressure delay is prevented and the vehicle deceleration required by the driver can be satisfied.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for realizing a vehicle control apparatus of the present invention will be described below based on the embodiments shown in the drawings.

  The brake control device according to the first embodiment maintains the hydraulic pressure of the friction brake constant at a timing earlier than the second shift request after the completion of the first shift. Prevent pressure increase delay.

[Configuration of Example 1]
FIG. 1 is a schematic system diagram showing a rear wheel drive vehicle to which the brake control device of the first embodiment is applied. The drive system of the vehicle of the first embodiment includes a motor generator MG, an automatic transmission AT, a propeller shaft PS, a final gear F and a differential D (both are expressed as F / D), a left drive shaft DSL, And a right drive shaft DSR, a left rear wheel RL (drive wheel), and a right rear wheel RR (drive wheel).

  The motor generator MG is a synchronous motor generator in which a permanent magnet is embedded in a rotor and a stator coil is wound around a stator. Based on a control command, the motor generator MG is applied with a three-phase alternating current generated by an inverter (not shown). The regenerative brake torque RB and other output torque and output rotation speed are controlled. The rotor of motor generator MG is connected to the input shaft of automatic transmission AT via a damper (not shown).

  The automatic transmission AT is a stepped automatic transmission that automatically switches stepped gear ratios such as forward 5 speed, reverse 1 speed, etc., according to the vehicle speed, accelerator opening, and the like. The output shaft of the automatic transmission AT is connected to the left and right rear wheels RL and RR via the propeller shaft PS, the differential DF, the left and right drive shafts DSL and DSR.

  The motor generator MG can operate as an electric motor that is driven to rotate by receiving power supplied from a battery (not shown) (this state is referred to as “powering”), or when the rotor is rotated by an external force. The battery can also be charged by functioning as a generator that generates electromotive force at both ends of the stator coil (hereinafter, this operation state is referred to as “regeneration”).

  During constant speed operation or acceleration operation of the vehicle, the motor generator MG is used as an electric motor, and the vehicle can be driven by the power. Further, during deceleration operation, motor generator MG is used as a generator to regenerate kinetic energy to charge the battery and to brake the vehicle with regenerative braking torque RB. In other words, the braking force (regenerative braking torque RB) can be output from the motor generator MG to the driving wheels via the automatic transmission AT. Regenerative brake torque RB output from motor generator MG is controlled by a command from brake controller 1 described later.

  The left and right rear wheels RL and RR are each provided with a friction brake actuator FBatr whose output torque (friction brake torque FB) is controlled by hydraulic pressure. The magnitude of the friction brake torque FB output from the friction brake actuator FBatr is controlled by a command from the brake controller 1 described later.

  Next, a vehicle control system according to the first embodiment will be described. As shown in FIG. 1, the control system has a brake controller 1 and an AT controller 2. The brake controller 1 and the AT controller 2 are connected to each other via a CAN communication line capable of exchanging information. FIG. 2 is a block diagram showing configurations of the brake controller 1 and the AT controller 2.

(AT controller)
As shown in FIG. 3, the AT controller 2 has a shift line map (shift map) in which a target shift stage is set in advance according to the vehicle speed V and the accelerator pedal opening APO. In FIG. 3, only the downshift line is shown. The AT controller 2 uses this shift map to determine whether to perform a shift based on the accelerator opening APO from the accelerator opening sensor 34 and the current vehicle speed Vcur from the vehicle speed sensor (AT output rotation speed sensor) 35. Further, based on the above determination, a shift control command, that is, a command for controlling the engagement and disengagement of the frictional engagement elements (clutch and brake) of the automatic transmission AT is calculated and output to the AT hydraulic control valve.

  As shown in FIG. 2, the AT controller 2 includes a current vehicle speed detection unit 21, a next shift request vehicle speed calculation unit 22, a current shift position detection unit 23, and a next shift position calculation as each unit related to the brake control of the present invention. Section 24 and motor rotation speed detection section 25 (vehicle deceleration reduction preventing means).

  The current vehicle speed detector 21 receives the sensor information input from the vehicle speed sensor 35 and detects the current vehicle speed Vcur.

  The next shift request vehicle speed calculation unit 22 calculates a vehicle speed Vnext required for the next shift based on the current vehicle speed Vcur using the shift map shown in FIG. Of a plurality of points where the horizontal axis where the accelerator opening APO is zero and the downshift line intersect, the vehicle speed at a point on the lower speed side (lower vehicle speed side) than the current vehicle speed Vcur is set as the next shift request vehicle speed Vnext. For example, when the current vehicle speed Vcur is at the position shown in FIG. 3, the next shift request vehicle speed Vnext is the vehicle speed at the point where the horizontal axis of the accelerator opening zero intersects the 3 → 2 shift line.

  The current shift position detection unit 23 detects the current shift position GPcur based on the current vehicle speed Vcur using the shift map shown in FIG. The current shift position GPcur is determined depending on what downshift line the point of the current vehicle speed Vcur located on the horizontal axis at which the accelerator opening APO is zero. For example, when the point of the current vehicle speed Vcur on the horizontal axis is at the position of FIG. 3, the current shift position GPcur is the third speed because it is sandwiched between the 4 → 3 shift line and the 3 → 2 shift line.

  The next shift position calculation unit 24 uses the shift map shown in FIG. 3 to calculate the next shift position GPnext based on the current shift position GPcur. In the brake control of the present invention, since the brake control before and after the downshift is targeted, the shift position on the low speed stage side from the current shift position GPcur is set as the next shift position GPnext. For example, when the current shift position GPcur is the third speed, the next shift position GPnext is the second speed.

  When the vehicle decelerates, the current vehicle speed Vcur moves in a decreasing direction from the position of the point in FIG. 3, and the current shift position GPcur and the next shift position GPnext coincide when they coincide with the point of the next shift request vehicle speed Vnext. To do. At this time, the target shift speed is switched from the third speed to the second speed, and execution of the next shift (downshift) is determined. The coincidence between the current shift position GPcur and the next shift position GPnext is detected by the brake controller 1 as a shift request. When receiving the shift start permission signal from the brake controller 1, the AT controller 2 outputs a shift control command to the AT hydraulic control valve, and executes the downshift.

  The motor rotation speed detection unit 25 receives the sensor information input from the motor rotation speed sensor 36 and detects the output rotation speed MGrev of the motor generator MG, in other words, the input rotation speed of the automatic transmission AT.

  Information on the accelerator opening APO, the current vehicle speed Vcur, the next shift request vehicle speed Vnext, the current shift position GPcur, and the next shift position GPnext is supplied to the brake controller 1 via the CAN communication line.

(Brake controller)
The brake controller 1 receives input of sensor information such as a brake stroke sensor 31 and a wheel speed sensor 32 that detects each wheel speed of the four wheels. For example, when the brake is depressed, a regenerative brake torque is generated with respect to the target brake torque TQ *. When RB alone is insufficient, regenerative cooperative brake control is performed so that the shortage is compensated by friction brake torque FB. Specifically, the command value RB * for regenerative brake torque and the command value FB * for friction brake torque are calculated, and each command value is output to the motor generator MG and the friction brake actuator FBatr for regenerative brake torque control. Coordinate with friction brake torque control.

  In addition, the brake controller 1 performs regenerative cooperative brake control including the following first to third controls in cooperation with the AT controller 2. That is, when shifting is requested while the regenerative brake torque RB is being output to the drive wheels RR and RL, the ratio of the regenerative brake torque RB in the target brake torque TQ * is reduced and the ratio of the friction brake torque FB is increased. A first control that replaces the regenerative brake torque RB with the friction brake torque FB, a second control that starts the shift after the replacement, and a regenerative brake torque RB at the target brake torque TQ * after the shift ends. And the third control to replace the friction brake torque FB with the regenerative brake torque RB by decreasing the ratio of the friction brake torque FB. As a result, as in the prior art, the occurrence of a shift shock or the like caused by executing a shift while the regenerative brake torque RB is output is prevented.

  As shown in FIG. 2, the brake controller 1 includes a target deceleration calculation unit 11, a target brake torque calculation unit 12, a shift request detection unit 13, and a maximum regenerative torque calculation as each unit related to the brake control of the present invention. Unit 14, a next shift request time calculation unit 15, a regenerative brake torque command value calculation unit 16, a friction brake torque command value calculation unit 17, a regenerative brake torque boost completion determination unit 18, a shift permission determination unit 19, (Vehicle deceleration reduction prevention means)

  The target deceleration calculation unit 11 receives an input of a brake pedal depression amount (brake stroke amount S) (not shown) from the brake stroke sensor 31, and calculates the target deceleration Gs * using the map 1 shown in FIG. . In Map 1, the increase rate of the target deceleration Gs * is set to increase as the brake stroke amount S increases.

  The target brake torque calculation unit 12 calculates the brake torque required for each of the four wheels to achieve the target deceleration Gs *, that is, the target brake torque TQ *. The target brake torque TQ * corresponds to the vehicle deceleration Gs (target deceleration Gs *) requested by the driver.

  The shift request detection unit 13 detects the presence or absence of a shift request based on information on the current shift position GPcur and information on the next shift position GPnext from the AT controller 2.

  The maximum regenerative torque calculating unit 14 detects the maximum regenerative torque RBmax0 on the regenerative unit side, that is, the maximum value of the regenerative brake torque RB that can be output by the motor generator MG, and compares this with the target brake torque TQ *. Thus, the maximum regenerative torque RBmax that can be actually used is calculated.

  The next shift request time calculation unit 15 calculates a deviation ΔV between the current vehicle speed Vcur and the next shift request vehicle speed Vnext, and based on this vehicle speed deviation ΔV and the target deceleration Gs *, a time until the next shift request is made. Calculate Tnext.

  The regenerative brake torque command value calculation unit 16 calculates a regenerative brake torque command value RB * according to various determination results as described later.

  The friction brake torque command value calculation unit 17 calculates a friction brake torque command value FB * based on the target brake torque TQ * and the regenerative brake torque command value RB *.

  The regenerative brake torque boost completion determination unit 18 determines whether the boost of the regenerative brake torque RB has been completed based on the regenerative brake torque command value RB * (n-1) and the maximum regenerative torque RBmax in the previous control cycle, that is, actually It is determined whether the regenerative brake torque RB is increased to the maximum regenerative torque RBmax.

  The shift permission determining unit 19 receives a shift request from the AT controller 2 and then completes switching from the regenerative brake to the friction brake, that is, when the reduction of the regenerative brake torque RB and the increase of the friction brake torque FB are completed. The shift start permission signal is output to the AT controller 2. Specifically, the shift is permitted when the regenerative brake torque command value RB * is zero, and the shift is not permitted when it is not zero.

[Operation of Example 1]
Hereinafter, in the vehicle of the first embodiment, the brake control calculated in the brake controller 1 while the driver is stepping on the brake pedal and applying the braking force will be described. FIG. 5 is a main flowchart showing the flow of this control. This calculation is repeatedly executed every predetermined time.

  In step S1, the target deceleration Gs * of the vehicle is calculated from the brake stroke amount S by the driver's operation using the map 1 shown in FIG. Thereafter, the process proceeds to step S2.

  In step S2, the brake torque required for each wheel to achieve the target deceleration Gs *, that is, the target brake torque TQ * is calculated from the target deceleration Gs * and the vehicle model. Thereafter, the process proceeds to step S3.

  In step S3, information on the current shift position GPcur is acquired from the AT controller 2. Thereafter, the process proceeds to step S4.

  In step S4, information on the next shift position GPnext is acquired from the AT controller 2. Thereafter, the process proceeds to step S5.

  In step S5, the current shift position GPcur and the next shift position GPnext are compared, and the presence / absence of a shift request from the AT controller 2 is detected. Specifically, if the current shift position GPcur and the next shift position GPnext are different, it is determined that there is no shift request, and the process proceeds to step S6. On the other hand, if the current shift position GPcur and the next shift position GPnext are the same, it is determined that a shift request has been made, and the process proceeds to step S19.

(When there is no shift request)
Steps S6 to S18 show the flow of calculating the friction brake torque command value FB * when there is no shift request.

  In step S6, the maximum regenerative torque RBmax, that is, the maximum available regenerative brake torque RB at the tire end is calculated. FIG. 6 is a sub-flowchart showing the calculation flow.

(Calculation of maximum regenerative torque on the regenerative unit side)
In step S61, the maximum regenerative torque RBmax0 on the regenerative unit side, that is, the maximum value of the regenerative brake torque that can be output by the motor generator MG is calculated. FIG. 7 is a sub-flowchart showing the calculation flow.

  In step S611, output rotation speed MGrev of motor generator MG is detected. Thereafter, the process proceeds to step S612.

  In step S612, the current gear ratio Gratio is calculated based on the motor speed MGrev (AT input speed) and the current vehicle speed Vcur (AT output speed). Thereafter, the process proceeds to step S613.

  In step S613, the maximum value of the regenerative brake torque that can be output from the motor generator MG on the output shaft of the motor generator MG, that is, the motor regenerative torque Tmg is calculated based on the motor speed MGrev using the map 2 shown in FIG. To do. Thereafter, the process proceeds to step S614.

  In step S614, the maximum regenerative torque RBmax0 on the regenerative unit side, that is, the maximum value of the regenerative brake torque that can be output by the motor generator MG at the tire end is calculated by RBmax0 = Tmg × Gratio × mTrqtoForce. That is, the gear ratio is converted by multiplying the motor regenerative torque Tmg by the gear ratio Gratio, and further converted to the brake torque generated at the tire end by multiplying by the constant mTrqtoForce. Thereafter, this subroutine is finished, and the routine goes to Step S62.

(Calculation of maximum regenerative torque)
In step S62, the maximum regenerative torque RBmax0 on the regenerative unit side is compared with the target brake torque TQ *. If the maximum regenerative torque RBmax0 on the regenerative unit side is equal to or less than the target brake torque TQ *, the process proceeds to step S63, and if greater than the target brake torque TQ *, the process proceeds to step S64.

  In step S63, the maximum value that can actually be used as the regenerative brake torque at the tire end is determined to be the maximum regenerative torque RBmax0 on the regenerative unit side, and the maximum regenerative torque on the regenerative unit side is determined as the maximum regenerative torque RBmax. Set the value of RBmax0. Thereafter, this subroutine is terminated, and the process proceeds to step S7.

  In step S64, it is determined that the maximum value actually usable as the regenerative brake torque at the tire end is the target brake torque TQ *, and the value of the target brake torque TQ * is set as the maximum regenerative torque RBmax. Thereafter, this subroutine is terminated, and the process proceeds to step S7.

  In step S7, the regenerative brake torque command value RB * (n-1) in the previous control cycle is compared with the maximum regenerative torque RBmax. If the previous regenerative brake torque command value RB * (n-1) matches the maximum regenerative torque RBmax, the actual regenerative brake torque RB is increased to the maximum regenerative torque RBmax, and the boost of the regenerative brake torque RB is completed. It moves to step S13. On the other hand, if the previous regenerative brake torque command value RB * (n-1) is less than the maximum regenerative torque RBmax, the actual regenerative brake torque RB is not increased to the maximum regenerative torque RBmax, and the regenerative brake torque RB It is determined that the increase in power is not completed, and the process proceeds to step S8.

(When regenerative braking torque has been increased)
Steps S13 and S14 show the flow of calculating the regenerative brake torque command value RB * and the friction brake torque command value FB * when the increase of the regenerative brake torque RB is completed.

  In step S13, after the previous shift is completed, the switch from the friction brake to the regenerative brake has been completed, and the next shift request has not been made. Set the regenerative torque RBmax (RB * = RBmax). That is, switching to the regenerative brake that has already been completed is continued.

  In step S14, the friction brake torque command value FB * is calculated by subtracting the regenerative brake torque command value RB * from the target brake torque TQ * (FB * = TQ * −RB *). Thereafter, the process proceeds to step S21.

  Here, when the maximum regenerative torque RBmax set in step S6 is the maximum regenerative torque RBmax0 on the regenerative unit side, the friction brake torque command value FB * takes a positive value. That is, the target brake torque TQ * is achieved when the friction brake supplies a torque (friction brake torque FB) that is insufficient for the regenerative brake torque RB. On the other hand, when the maximum regenerative torque RBmax set in step S6 is the target brake torque TQ *, the friction brake torque command value FB * takes a value of zero. That is, the target brake torque TQ * is achieved only by the regenerative brake torque RB, and the friction brake torque FB becomes unnecessary.

(When regenerative braking torque has not been increased)
Steps S8 to S12 and S15 to S18 show the flow of calculation of the regenerative brake torque command value RB * and the friction brake torque command value FB * when the increase of the regenerative brake torque RB is not completed.

  In step S8, information on the next shift request vehicle speed Vnext is acquired from the AT controller 2. Thereafter, the process proceeds to step S9.

  In step S9, information on the current vehicle speed Vcur is acquired from the AT controller 2. Thereafter, the process proceeds to step S10.

  In step S10, a vehicle speed deviation ΔV (= | Vnext−Vcur |), that is, a deviation between the current vehicle speed Vcur and the next shift request vehicle speed Vnext is calculated. Thereafter, the process proceeds to step S11.

  In step S11, based on the vehicle speed deviation ΔV and the target deceleration Gs *, a time Tnext from the current time until the next shift request is calculated. Specifically, Tnext = ΔV / Gs *. Thereafter, the process proceeds to step S12.

  In step S12, a time Tnext until the next shift request is made is compared with a predetermined friction brake torque holding time Chold. If the time Tnext until the next shift request is longer than the predetermined friction brake torque holding time Chold, the process proceeds to step S15. If the time Tnext is less than the predetermined friction brake torque holding time Chold, the process proceeds to step S17. . The holding of the friction brake torque FB is specifically a constant holding of the hydraulic pressure (hydraulic pressure) of the friction brake actuator FBatr.

(When the time until the next shift request is longer than the predetermined time)
In step S15, a regenerative brake torque command value RB * is calculated. Specifically, the regenerative brake torque command value RB * is increased by a predetermined value CRBInc from the previous calculated value RB * (n−1) (RB * = RB * (n−1) + CRBInc). Thereafter, the process proceeds to step S16.

  In step S16, as in step S14, after calculating the friction brake torque command value FB *, the process proceeds to step S21.

  Here, at step S15, the regenerative brake torque command value RB * is gradually increased for each control period until the time Tnext until the next shift request is made becomes equal to or less than the predetermined holding time Chold. In step S16, the friction brake torque command value FB * is calculated by subtracting it from the target brake torque TQ *, which is a constant value, so the friction brake torque command value FB * is controlled until Tnext falls below Chold. Decreases gradually with each cycle.

(When the time until the next shift request is shorter than the predetermined time)
In step S17, the regenerative brake torque command value RB * is held as the previous calculated value RB * (n-1). Specifically, the regenerative brake torque command value RB * is calculated from RB * = RB * (n−1). Thereafter, the process proceeds to step S18.

  In step S18, as in step S14, after calculating the friction brake torque command value FB *, the process proceeds to step S21.

  Here, at step S17, the regenerative brake torque command value RB * is held at the previous calculated value RB * (n−1). In step S18, the friction brake torque command value FB * is calculated by subtracting it from the target brake torque TQ *, which is a constant value. The calculated value FB * (n-1) is held.

(When there is a shift request)
Steps S19 and S20 show the flow of calculating the friction brake torque command value FB * when there is a shift request.

  In step S19, the regenerative brake torque command value RB * is decreased by a predetermined value CRBDec from the previous calculated value RB * (n-1). Specifically, the regenerative brake torque command value RB * is calculated by RB * = RB * (n−1) −CRBDec. Thereafter, the process proceeds to step S20.

  In step S20, as in step S14, the friction brake torque command value FB * is calculated, and then the process proceeds to step S21.

  Here, at step S19, the regenerative brake torque command value RB * gradually decreases for each control period until it reaches zero. In step S20, the friction brake torque command value FB * is calculated by subtracting from the target brake torque TQ *, which is a constant value. Therefore, the friction brake torque command value FB * is the maximum value until it reaches the maximum value TQ *. During this period, it gradually increases with each control cycle.

(Servo control)
In step S21, the regenerative brake torque command value RB * calculated in steps S13, S15, S17, and S19 is output to motor generator MG. Motor generator MG outputs regenerative brake torque RB based on this command value RB *, and this output value is controlled by a servo mechanism.

  In step S22, the friction brake torque command value FB * calculated in steps S14, S16, S18, and S20 is output to the friction brake actuator FBatr of each wheel. Each friction brake actuator FBatr outputs a friction brake torque FB based on this command value FB *, and this output value is controlled by a servo mechanism.

(Time chart)
FIG. 8 shows the brake control according to the first embodiment after the first shift is completed until the second shift is actually requested until the second shift is actually started. It is the time chart shown in contrast with. With respect to the regenerative brake torque, friction brake torque, and vehicle deceleration, Example 1 is indicated by a solid line, and the prior art is indicated by a broken line. Hereinafter, this time chart will be described. For the sake of explanation, it is assumed that the first shift is a downshift from 4th speed to 3rd speed (4 → 3 shift) and the second shift is a downshift from 3rd speed to 2nd speed (3 → 2 shift). Also, in the brake torque time chart, the vertical direction is defined as the positive direction. Even when the driver is stepping on the brake pedal, the first gear shift is a downshift from the third gear to the second gear (3 → 2 gear shift), and the second gear shift is from the second gear to the third gear. There may be a case of upshifting to a high speed (2 → 3 shift).

  At time t1, the first shift is completed. At time t4, the second shift is started. Brake control is performed between time t1 and time t4 when no speed change is performed.

  At time t1, the first shift (4 → 3 shift) is completed, and the brake control is started. Here, the target deceleration Gs * and the target brake torque TQ * are calculated (steps S1 and S2 in FIG. 5). Since it is assumed that the target deceleration Gs * is constant throughout all the time points, the target brake torque TQ * calculated based on the target deceleration Gs * is also constant.

  Further, the third speed that is the current shift position GPcur is detected, and the second speed that is the next shift position GPnext is calculated based on the shift map shown in FIG. 3 (steps S3 and S4). GPcur (3rd speed) ≠ GPnext (2nd speed) until time t3 when the vehicle speed V becomes the vehicle speed Vnext at which the second speed change (3 → 2 speed change) is requested. Therefore, until time t3, it is determined that there is no shift request, and first, maximum regenerative torque RBmax is calculated (steps S5 and S6).

  This time chart shows an example when the maximum regenerative torque RBmax0 of the motor generator MG exceeds the target brake torque TQ *, that is, when the target brake torque TQ * is set as the maximum regenerative torque RBmax (step S61). ~ S64).

  In addition, this time chart shows an example in which after time t1, the regenerative brake torque RB does not reach the maximum regenerative torque RBmax (= target brake torque TQ *), and the increase of the regenerative brake torque RB is not completed ( Step S7). Therefore, the time Tnext until the next shift (3 → 2 shift) is calculated (steps S8 to S11).

  Between times t1 and t2, since Tnext is longer than the predetermined holding time Chold, the regenerative brake torque RB is gradually increased by a predetermined value CRBInc for each control period (steps S15 and S21). At the same time, the hydraulic pressure of the friction brake actuator FBatr is gradually decreased, and the friction brake torque FB is gradually decreased by a predetermined value CRBInc for each control cycle (steps S16 and S22).

  At time t2, Tnext switches to a predetermined holding time Chold or less, so the regenerative braking torque RB is held at the value at that time (steps S12, S17, S21).

  Between time t2 and t3, Tnext is equal to or less than the predetermined holding time Chold, so the regenerative braking torque RB is held at the value at time t2 (steps S17 and S21). At the same time, the friction brake torque FB is held at the value at time t2 (steps S18 and S22). In other words, the hydraulic pressure of the friction brake actuator FBatr is held at a constant value.

  When the current vehicle speed Vcur decreases to the second shift request vehicle speed Vnext at time t3, the current shift position GPcur and the next shift position GPnext coincide with each other, and a second shift is requested (step S5). Therefore, after t3, the regenerative brake torque RB is gradually decreased by a predetermined value CRBDec for each control cycle (steps S19 and S21). At the same time, the hydraulic pressure of the friction brake actuator FBatr is gradually increased, and the friction brake torque FB is gradually increased by a predetermined value CRBDec for each control cycle (steps S20 and S22).

  At time t4, the regenerative brake torque RB becomes zero and the regenerative brake torque RB is reduced, and the friction brake torque FB becomes the target brake torque TQ *, and the increase of the friction brake torque FB is completed. Thus, when the switching from the regenerative brake to the friction brake is completed, the second shift is started.

(Operational effect of the first embodiment in comparison with the prior art)
In the prior art, when the second shift request is made at t3 during the switching from the friction brake to the regenerative brake after t1 when the first shift is completed, the friction brake is suddenly changed from the reduced pressure state to the increased pressure state. Will be switched. In other words, the slope of the straight line indicating the change over time of the friction brake torque command value FB * changes from a right shoulder rise (decompression) to a right shoulder fall (pressure increase) in FIG. It changes rapidly. Therefore, the angle α shown in FIG. 8 is relatively small.

  Therefore, after t3, the pressure increase delay of the friction brake actuator FBatr occurs with respect to the friction brake torque command value FB *, and the actual friction brake torque value FB temporarily decreases from the command value FB *. As the friction brake torque FB decreases, the total actual brake torque TQ temporarily decreases with respect to the target brake torque TQ *. Therefore, depending on the length of time until the second shift request is made after the completion of the first shift, the second shift request is made during switching from the friction brake to the regenerative brake, thereby reducing the vehicle. There is a problem that the speed Gs is temporarily insufficient with respect to the target deceleration Gs * requested by the driver.

  In contrast, the brake control device of the first embodiment keeps the friction brake pressure constant at t2 at a timing earlier than t3 where the second shift request is made after t1 when the first shift is completed. Thus, the friction brake pressure increase delay at the time of the second shift request is prevented.

  That is, after the completion of the first shift, the time Tnext until the second shift request is calculated is calculated. Further, a predetermined holding time Chold is provided, and from the time t2 when Tnext switches to Chold or less, the friction brake actuator The fluid pressure of FBatr was held at a constant value for a certain time Chold. Thus, the friction brake is not suddenly switched from the reduced pressure state to the increased pressure state before and after t3 when the second shift request is made. The friction brake torque command value FB * is maintained at a constant value until immediately before t3 when the second speed change request is made, and the slope of the straight line indicating the change over time is flat (retained) before and after t3. It gradually changes from lower to lower right (intensification). Therefore, the angle α1 shown in FIG. 8 is relatively large (α1> α).

  Therefore, after t3, the delay in pressure increase of the friction brake actuator FBatr with respect to the friction brake torque command value FB * is suppressed, and the temporary decrease of the actual value FB with respect to the friction brake torque command value FB * is also the magnitude and time. Is smaller than the prior art. Therefore, the temporary decrease of the total actual brake torque TQ with respect to the target brake torque TQ * is also small, so that the time Tnext from when the first shift is completed until the second shift request is made is not concerned. Thus, a situation where the vehicle deceleration Gs is insufficient with respect to the target deceleration Gs * requested by the driver is prevented.

(Experimental result)
FIG. 9 shows an experimental result of the friction brake pressure increase delay at the time of the second shift request in comparison between the prior art and the first embodiment. In the prior art, the friction brake (friction brake torque command value FB *) is suddenly switched from the reduced pressure state to the increased pressure state before and after t3 when the second shift request is made. Therefore, the actual increase in the friction brake torque actual value FB corresponding to the increase in the friction brake torque command value FB * after t3 actually occurs 170ms after t3, and the friction brake pressure increases by this amount of time. Delay occurs.

  On the other hand, in the first embodiment, the friction brake (friction brake torque command value FB *) is gradually switched from the holding state to the pressure increasing state before and after t3 when the second shift request is made. For this reason, the actual increase in the friction brake torque actual value FB corresponding to the increase in the friction brake torque command value FB * after t3 actually occurs earlier than the conventional technology, 100 ms after t3. There is no delay in brake pressure increase. In other words, in the brake control device of the first embodiment, the delay in pressure increase of the friction brake can be eliminated by 70 ms from 170 ms of the conventional technology, and the time is shortened by about 41% compared to the conventional technology. is doing.

(Supplementary explanation)
In the prior art, when strong deceleration is required, that is, when the target deceleration Gs * is large, the first shift is completed and the second shift request is made while switching from the friction brake to the regenerative brake. May be made. That is, the pressure increase delay of the friction brake is likely to occur.

  In the brake control device of the first embodiment, the time Tnext until the second shift request is made is calculated based on the vehicle speed deviation ΔV and the target deceleration Gs * (Tnext = ΔV / Gs *). When the brake stroke amount S is large and the target deceleration Gs * is large, the calculated Tnext is shortened accordingly. Therefore, the larger the target deceleration Gs *, the shorter the time until Tnext switches to the predetermined holding time Chold or less, and the timing for starting the constant holding of the friction brake torque FB is advanced accordingly. In other words, even when the target deceleration Gs * is large and the time until the second shift request is made is short, the holding time Chold can be ensured. Therefore, a situation where the actual vehicle deceleration Gs is insufficient with respect to the target deceleration Gs * requested by the driver is prevented regardless of the magnitude of the target deceleration Gs *.

  If the predetermined holding time Chold itself is set to be long, the time until Tnext switches to the holding time Chold or less is shortened, and the timing t2 at which the constant holding of the friction brake torque FB is started is accordingly advanced. At this time, as long as the rate of decrease in the friction brake torque command value FB * (corresponding to the predetermined value CRBInc) is constant, the amount of decrease in the friction brake torque FB from t1 to t2 is small, so the retained friction brake torque FB The value of increases. Therefore, the time (t3 to t4) required to complete the increase of the retained friction brake torque FB after t3 when the second speed change request is made is also the increase speed (predetermined value) of the friction brake torque command value FB *. As long as CRBDec is constant). In other words, after t3 when the second shift request is made, the time until t4 at which the second shift can actually be started is earlier than that of the conventional technique (t6), so that the shift response is good.

  However, if the predetermined holding time Chold is set to be long, the value of the friction brake torque FB to be held also increases as described above. In other words, the value of the regenerative braking torque RB that is held decreases. For this reason, the integrated amount of regenerative energy is suppressed, and the fuel consumption cannot be improved by this amount.

  On the other hand, if the predetermined holding time Chold is set to be short, the regenerative energy increases, but the above-described shift response cannot be improved. Also, if the holding time Chold is set too short, the friction brake fluid pressure holding state cannot be substantially maintained, the friction brake fluid pressure state change cannot be effectively suppressed, and the friction brake pressure increase delay cannot be prevented. There is a fear.

  Therefore, the length of the predetermined holding time Chold is set by taking into account the advantages and disadvantages such as improvement of shift response and fuel consumption, and effective prevention of insufficient vehicle deceleration.

  Note that, as indicated by a two-dot chain line in FIG. 8, the friction brake torque command value FB * may be maintained even after t3 when the second shift request is made. At this time, the continuation of the holding is a range in which the time when the pressure increase of the friction brake torque FB after the end of holding is completed is not later than the time t5 when the pressure increase of the friction brake torque FB is not performed (broken line). I will do it in.

  When such a configuration is adopted, the time Chold for holding the regenerative brake torque RB is substantially lengthened, so the amount of accumulated regenerative energy increases, and fuel consumption can be improved by this amount ( The hatched portion in FIG. In addition, since the completion time t5 of increasing the friction brake torque FB after completion of the holding is not different from that in the prior art, there is no possibility that the shift response will be reduced.

[Effect of Example 1]
The brake control device according to the first embodiment can obtain the effects listed below.

  (1) The output rotation of the motor generator MG, which is interposed between the motor generator MG and the drive wheels RR, RL, is changed by at least two speeds (forward 5 speed, reverse 1 speed, etc.) to drive wheels RR, RL. Friction brake for generating friction brake torque FB on drive wheels RR and RL by hydraulic transmission controlled automatic transmission AT, shift control means (AT controller 2) for controlling shift by automatic transmission AT, and hydraulically controlled actuator FBatr A regenerative brake torque control means for controlling the regenerative brake torque RB output to the drive wheels RR and RL by the regenerative torque generated by the motor generator MG, a friction brake torque control means for controlling the friction brake torque FB, and a driver Target brake torque calculation to calculate the target brake torque TQ * of the drive wheels RR and RL that achieves the target deceleration Gs * of the vehicle according to the brake operation (brake stroke amount S) When shifting is requested while the output means (target deceleration calculation unit 11 and target brake torque calculation unit 12) and the regenerative brake torque RB are being output to the drive wheels RR and RL, the target brake torque TQ * The first control for reducing the ratio of the regenerative brake torque command value RB * and increasing the ratio of the friction brake torque command value FB * to replace the regenerative brake torque RB with the friction brake torque FB; After the second control to start the shift and the above shift, the ratio of the regenerative brake torque command value RB * in the target brake torque TQ * is increased and the ratio of the friction brake torque command value FB * is decreased to thereby increase the friction brake torque. Regenerative cooperative brake control means (brake controller 1, AT controller 2) for performing third control to replace FB with regenerative brake torque RB; In the vehicle brake control apparatus, the next shift request prediction means for predicting the second shift request during the third control after the end of the first shift (next shift request time calculation unit 15, steps S1, S8 to S11). Etc.) and the regenerative cooperative brake control means (brake controller 1, AT controller 2) starts the first control when the second shift is requested during the third control after the end of the first shift. When the friction brake torque FB is switched from decrease to increase, vehicle deceleration reduction prevention means (each part 11-19 of the brake controller 1) that suppresses fluctuations in the amount of change per hour in the friction brake torque command value FB *. And each part 21 to 25) of the AT controller 2.

  Therefore, when the second speed change request is made, the friction brake is not suddenly switched from the reduced pressure state to the increased pressure state, but is gradually switched from the holding state to the increased pressure state, so that an abrupt hydraulic pressure change of the friction brake can be suppressed. Therefore, the friction brake pressure increase delay at the time of the second shift request can be suppressed, and the vehicle deceleration Gs requested by the driver can be satisfied.

  (2) The vehicle deceleration reduction preventing means (the parts 11 to 19 of the brake controller 1 and the parts 21 to 25 of the AT controller 2) requires the second shift during the third control after the end of the first shift. In the meantime, friction brake torque holding means (steps S11, S12, S15 to S18, etc.) for holding the friction brake torque command value FB * constant is provided.

  That is, after t1 when the first shift is completed, the friction brake fluid pressure is held at time t2 that is earlier than time t3 when the second shift request is present. Therefore, when the second speed change request is made, the friction brake is not suddenly switched from the reduced pressure state to the increased pressure state, but is gradually switched from the holding state to the increased pressure state, so that a sudden change in hydraulic pressure of the friction brake can be suppressed. Therefore, regardless of the length of time Tnext until the second shift request, the friction brake pressure increase delay at the time of the second shift request can be suppressed, and the vehicle deceleration Gs requested by the driver is satisfied. Can be made. Further, after t3 when the second shift request is made, the time until t5 at which the second shift can actually be started is shortened, so that there is an effect that the responsiveness of the shift is good.

  (3) The friction brake torque holding control means advances the holding start time of the friction brake torque command value FB * as the target deceleration Gs * increases.

  That is, the time Tnext until the second shift request is calculated is calculated based on the target deceleration Gs * (Tnext = ΔV / Gs *) (step S11), and the holding of the friction brake torque FB is started based on Tnext. The timing t2 is determined (steps S12, S15 to S18). Therefore, as the target deceleration Gs * is larger, the friction brake torque FB holding start timing t2 is earlier, and the vehicle deceleration Gs required by the driver is satisfied regardless of the target deceleration Gs *. Has the effect of being able to.

  (4) The friction brake torque holding control means continues to hold the friction brake torque command value FB * for a predetermined time after t3 when the second shift is requested during the third control after the end of the first shift. It is good to do.

  In this case, since the time Chold for holding the regenerative brake torque RB is substantially increased, the integrated amount of regenerative energy increases, and the fuel consumption can be improved by this amount.

  The brake control device according to the second embodiment is configured so that the amount of replacement of the friction brake torque FB with the regenerative brake torque RB (the reduction rate of the friction brake torque FB) is earlier than the second shift request after the completion of the first shift. By starting the restriction, a delay in pressure increase of the friction brake at the time of the second shift request is prevented.

[Configuration of Example 2]
The configuration of the brake control device of the second embodiment is the same as that of the first embodiment (see FIGS. 1 and 2). However, unlike the first embodiment, the brake controller 1 of the second embodiment does not have the next shift request time calculation unit 15.

  The regenerative brake torque command value calculation unit 16 according to the second embodiment includes a command value correction unit 16a (not shown). The command value correction unit 16a calculates an increase amount CRBInc of the regenerative brake torque command value RB * based on the deviation ΔV between the current vehicle speed Vcur and the next shift request vehicle speed Vnext using the map 3 shown in FIG.

  Further, the command value correction unit 16a changes the reference line used in the map 3 based on the deviation ΔGs * between the target deceleration Gs * calculated this time and the target deceleration Gs * (n−1) calculated last time. . Specifically, in the map 3, the reference line 1 when the deviation ΔGs * is near zero (ΔGs * ≈0), and the upper side, that is, the positive direction side when the deviation ΔGs * is a positive value (ΔGs *> 0). When the deviation ΔGs * is a negative value (ΔGs * <0), the shift is made to the reference line 3 on the lower side, that is, the negative direction side. The command value correction unit 16a calculates the increase amount CRBInc of the regenerative brake torque command value RB * by using the reference line thus changed according to the value of the deviation ΔGs *.

[Operation of Example 2]
Hereinafter, in the vehicle according to the second embodiment, the brake control will be described while the driver is stepping on the brake pedal to apply the braking force. FIG. 10 is a flowchart showing the flow of control. This calculation is repeatedly executed every predetermined time.

  In step S30, the target deceleration Gs * of the vehicle is calculated from the brake stroke amount S as in step S1 of the first embodiment. Thereafter, the process proceeds to step S31.

  In step S31, the target brake torque TQ * is calculated as in step S2 of the first embodiment. Thereafter, the process proceeds to step S32.

  In step S32, the current vehicle speed Vcur information is acquired from the AT controller 2 in the same manner as in step S9 of the first embodiment. Thereafter, the process proceeds to step S33.

  In step S33, information on the accelerator opening APO is acquired from the AT controller 2. Thereafter, the process proceeds to step S34.

  In step S34, as in step S8 of the first embodiment, information on the next shift request vehicle speed Vnext is acquired from the AT controller 2. Thereafter, the process proceeds to step S35.

  In step S35, the maximum regenerative torque RBmax is calculated as in step S6 of the first embodiment. Thereafter, the process proceeds to step S36.

  In step S36, the vehicle speed deviation ΔV (= | Vnext−Vcur |) is calculated as in step S10 of the first embodiment. Thereafter, the process proceeds to step S37.

  In step S37, a deviation ΔGs * between the target deceleration Gs * calculated in the current control cycle and the target deceleration Gs * (n−1) calculated in the previous control cycle is calculated. Thereafter, the process proceeds to step S38.

  In step S38, the presence / absence of a shift request from the AT controller 2 is detected as in step S5 of the first embodiment. If there is no shift request, the process proceeds to step S39. If there is a shift request, the process proceeds to step S41.

(When there is no shift request)
Steps S39, S40, and S44 show the flow of calculating the friction brake torque command value FB * when there is no shift request.

  In step S39, it is shown in FIG. 10 on the assumption that the regenerative brake torque command value RB * (n-1) in the previous control cycle is less than the maximum regenerative torque RBmax and the regenerative brake torque RB has not been boosted. Using map 3, increase amount CRBInc of regenerative brake torque command value RB * is calculated. At this time, the reference line to be used is changed based on the target deceleration deviation ΔGs *. Thereafter, the process proceeds to step S40. Note that if the regenerative brake torque command value RB * (n-1) has already been increased to the maximum regenerative torque RBmax and the boost of the regenerative brake torque RB has been completed, steps S13 and S14 in Example 1 are performed. The same control is performed.

  In step S40, the regenerative brake torque command value RB * is increased from the previous calculated value RB * (n-1) by the calculated value CRBInc. Specifically, the regenerative brake torque command value RB * is calculated by RB * = RB * (n−1) + CRBInc. Thereafter, the process proceeds to step S44.

(When there is a shift request)
Steps S41 to S44 show the flow of calculating the friction brake torque command value FB * when there is a shift request.

  In step S41, as in step S19 of the first embodiment, the regenerative brake torque command value RB * is reduced by a predetermined value CRBDec from the previous calculated value RB * (n-1) (RB * = RB * (n- 1) -CRBDec). Thereafter, the process proceeds to step S42.

  In step S42, the shift permission determination unit 19 determines whether or not the regenerative brake torque command value RB * is zero. If the regenerative brake torque command value RB * is zero, the process proceeds to step S43. If not zero, the process moves to step S44.

  In step S43, the shift permission determining unit 19 outputs a shift permission signal to the AT controller 2. Thereafter, the process proceeds to step S44.

  In step S44, as in step S14 of the first embodiment, the friction brake torque command value FB * is calculated (FB * = TQ * −RB *). Thereafter, the process proceeds to step S45.

  In step S45, each value Gs *, RB *, etc. calculated in the current control cycle is stored. The stored value is used in the next control cycle.

(Time chart and effect of the second embodiment)
FIGS. 11 to 13 are time charts showing the brake control of the second embodiment after the end of the first shift until the second shift is requested and the second shift is actually started. . 11 is a time chart when the brake stroke amount S is substantially constant, FIG. 12 is a time chart when the brake pedal is stepped on during brake control, and FIG. 13 is a time chart when the brake pedal is stepped back.

(Time chart when the brake stroke amount is almost constant)
FIG. 11 shows a case where the deviation ΔGs * of the target deceleration is substantially zero (ΔGs * ≈0) because the brake stroke amount S is substantially constant. Similar to the first embodiment, the second embodiment is indicated by a solid line, and the prior art is indicated by a broken line.

  At time t1, the first shift is completed. At time t5, the second shift is started. Brake control is performed between times t1 and t5.

  At time t1, the first shift (4 → 3 shift) is completed, and the brake control is started. The target deceleration Gs *, its deviation ΔGs *, and the target brake torque TQ * are calculated (steps S30, S31, S37). Since the target deceleration Gs * is substantially constant throughout all time points (ΔGs * ≈0), the target brake torque TQ * calculated based on the target deceleration Gs * is also substantially constant. Since the deviation Gs * is substantially zero (ΔGs * ≈0), the reference line 1 is used in the map 3 for calculating the value CRBInc.

  From time t1 to t4, it is determined that there is no shift request, and the regenerative brake torque RB is gradually increased by the value CRBInc for each control cycle (steps S38 to S40). At the same time, the hydraulic pressure of the friction brake actuator FBatr is gradually decreased, and the friction brake torque FB is gradually decreased by the value CRBInc for each control cycle (step S44).

  Since the vehicle speed deviation ΔV (= | Vnext−Vcur |) is larger than the value ΔV1 shown in the map 3 from time t1 to time t2, the calculated value CRBInc is constant (step S39). Therefore, with time, the regenerative brake torque command value RB * increases at a constant rate, and at the same time, the friction brake torque command value FB * decreases at a constant rate (steps S40 and S44).

  From time t2 to time t3, the vehicle speed deviation ΔV is smaller than the value ΔV1 shown in the map 3 and larger than the value ΔV3, so the calculated value CRBInc decreases at a constant rate (step S39). Therefore, the increase rate of the regenerative brake torque command value RB * gradually decreases with time, and the decrease rate of the friction brake torque command value FB * gradually decreases (steps S40 and S44). That is, the amount of replacement from the friction brake torque FB to the regenerative brake torque RB is limited.

  Between time t3 and t4, since the vehicle speed deviation ΔV is smaller than the value ΔV3 shown in the map 3, the calculated value CRBInc is zero and constant (step S39). Therefore, the regenerative brake torque command value RB * is held at a constant value, and at the same time, the friction brake torque command value FB * is held at a constant value (steps S40 and S44).

  When the current vehicle speed Vcur decreases to the second shift request vehicle speed Vnext at time t4, the second shift is requested. Therefore, after t4, the regenerative brake torque RB is gradually decreased by a predetermined value CRBDec for each control cycle (steps S38 and S41). At the same time, the hydraulic pressure of the friction brake actuator FBatr is gradually increased, and the friction brake torque FB is gradually increased by a predetermined value CRBDec for each control cycle (step S44).

  At time t5, the regenerative brake torque command value RB * becomes zero and the reduction of the regenerative brake torque RB is completed, and the friction brake torque command value FB * becomes the target brake torque TQ * and the increase of the friction brake torque FB is completed. . Thus, when the switching from the regenerative brake to the friction brake is completed, the second shift is started.

(Operational effect when the brake stroke amount is substantially constant)
In the prior art, as described in the first embodiment, the slope of the straight line indicating the time change of the friction brake torque command value FB * increases from right shoulder (decompression) to right before and after t4 when the second shift request is required. The angle a suddenly changes to a shoulder drop (pressure increase), and the angle α shown in FIG. 11 is relatively small.

  In contrast, the brake control device of the second embodiment gradually decreases the decreasing gradient of the friction brake torque command value FB * until t4 when the second shift request is made after t1 when the first shift is completed. As a result, the state change of the friction brake pressure at t4 is alleviated. As a result, the friction brake pressure increase delay at the time of the second shift request (immediately after t4) is prevented.

  In other words, as the current vehicle speed Vcur approaches the next shift request vehicle speed Vnext, the amount of replacement from the friction brake torque FB to the regenerative brake torque RB is limited, and the decreasing gradient of the friction brake torque command value FB * gradually decreases. The friction brake torque command value FB * is kept constant immediately before t4. Thus, the friction brake is not suddenly switched from the reduced pressure state to the increased pressure state before and after t4 when the second shift request is made. The slope of the straight line indicating the time change of the friction brake torque command value FB * gradually changes from the flat state (holding) in FIG. 11 to the lower right side (increasing pressure) before and after t4. Therefore, the angle α2 shown in FIG. 11 is relatively large (α2> α).

  Therefore, after t4, the delay in pressure increase of the friction brake actuator FBatr with respect to the friction brake torque command value FB * is suppressed, and regardless of the length of time until the second shift request is made after the completion of the first shift, A situation where the vehicle deceleration Gs is insufficient with respect to the target deceleration Gs * requested by the driver is prevented.

  In addition, since the decrease gradient of the friction brake torque command value FB * gradually becomes gentle, the decrease range of the friction brake torque RB from t1 to t4 is smaller than that of the conventional technology, and the value of the retained friction brake torque FB is growing. Therefore, after t4 when the second shift request is made, the time (t4 to t5) required to complete the increase of the friction brake torque FB is also shortened. In other words, after t4 when the second shift request is made, the time until t5 at which the second shift can actually be started is earlier than that of the prior art (t6), so that the shift response is good.

  As in the first embodiment, the friction brake torque command value FB * may be maintained for a predetermined time after t4 when the second shift request is made. In this case, since the time for holding the regenerative brake torque RB is substantially lengthened, the amount of accumulated regenerative energy increases as in the first embodiment, and the fuel efficiency can be improved by that amount.

(Time chart when the brake pedal is increased)
FIG. 12 shows a case where the deviation ΔGs * of the target deceleration becomes a positive value (ΔGs *> 0) because the brake pedal is depressed during the brake control. In addition, when the deviation ΔGs * changes from zero to a positive value, the reference line of the map 3 is not changed, that is, the increase amount CRBInc of the regenerative braking torque command value RB * is based on the change of the deviation ΔGs *. A case where no correction is made is indicated by a broken line.

  Since the target deceleration Gs * is substantially constant from time t1 to time t3 (ΔGs * ≈0), the reference line 1 is used in the map 3 for calculating the value CRBInc.

  Between time t1 and t2, since the vehicle speed deviation ΔV is larger than the value ΔV1 shown in the map 3, the regenerative brake torque command value RB * increases at a constant rate and the friction brake torque command value FB * is constant. Decrease at a rate (steps S40 and S44).

  From time t2 to t3, the vehicle speed deviation ΔV is smaller than the value ΔV1 shown in the map 3 and larger than the value ΔV3. Therefore, the increase rate of the regenerative brake torque command value RB * gradually decreases, and at the same time, the friction brake The magnitude of the decrease rate of the torque command value FB * gradually decreases (steps S40 and S44).

  Between time t3 and t6, the brake pedal is stepped on, and the target deceleration deviation ΔGs * in each control cycle becomes a positive value (ΔGs *> 0). It is assumed that the deviation ΔGs * is substantially constant in each control cycle, and the target brake torque TQ * is also increased at a substantially constant rate.

  Since the deviation ΔGs * is a positive value (ΔGs *> 0) from the time t3 to the time t5 when the second shift request is present, the reference line 2 is used in the map 3 for calculating the value CRBInc. Therefore, the value CRBInc after the reference line change is corrected to the positive direction side. That is, the increase rate of the regenerative brake torque command value RB * and the decrease rate of the friction brake torque command value FB * between time t3 and time t5 are larger than when the reference line is not changed (broken line).

  The friction brake torque command value FB * is calculated by subtracting the regenerative brake torque command value RB * from the target brake torque TQ *. Further, the target brake torque TQ * increases at a substantially constant rate from time t3 to time t5. For this reason, even when the increase rate of the regenerative brake torque command value RB * is suddenly increased by changing the reference line, the decrease rate of the friction brake torque command value FB * is rapidly increased before and after the reference line change time t3. The change is suppressed, and the friction brake torque command value FB * continues to decrease at a substantially constant rate. Therefore, the state change of the friction brake is suppressed compared to the case where the reference line is not changed (broken line) before and after the brake pedal is increased.

  In addition, during the period from time t3 to t5, the amount of increase in the regenerative brake torque command value RB * and the decrease in the friction brake torque command value FB * are reduced by limiting the replacement amount to the regenerative brake torque RB using map 3. Each change gradient of rate becomes gentle. That is, during the period from time t3 to t4, the vehicle speed deviation ΔV is smaller than the value ΔV1 shown in the map 3 and larger than the value ΔV3, so that the decreasing gradient of the friction brake torque command value FB * is gentle (step S40). , S44).

  Further, since the vehicle speed deviation ΔV is smaller than ΔV3 from time t4 to t5, the calculated value CRBInc is a constant value (step S39). Therefore, the regenerative brake torque command value RB * increases at a constant rate CRBInc, and at the same time, the friction brake torque command value FB * decreases or increases at a substantially constant rate (the increase rate of the target brake torque TQ * depends on the regenerative brake torque command value). RB * increase rate is greater than CRBInc) (steps S40 and S44).

  Therefore, the friction brake is not switched from the sudden pressure reduction state to the pressure increase state before and after t5 when the second shift request is present. In other words, the angle α2 ′ shown in FIG. 12 is larger than the angle α (see FIG. 11) in the prior art (α2 ′> α).

  At time t5, when the current vehicle speed Vcur decreases to the second shift request vehicle speed Vnext, the second shift is required. Therefore, after t5, the regenerative brake torque RB is gradually decreased by the value CRBDec (steps S38, S41). ). At the same time, the friction brake torque FB is gradually increased by the value CRBDec (step S44).

  At time t6, the increase in the target deceleration Gs * ends, and the target deceleration Gs * becomes substantially constant (ΔGs * ≈0). When the reduction of the regenerative brake torque RB and the increase of the friction brake torque FB are completed at time t7, the second shift is started.

(Operational effect when the brake pedal is depressed)
The target brake torque TQ * increases while the brake pedal is depressed. Here, when the reference line 1 of the map 3 is used without change, as shown by the broken line in FIG. 12, the correction amount of the increasing gradient CRBInc of the regenerative brake torque command value RB * is the increase of the target brake torque TQ *. Remain small before and after. Therefore, it is necessary to increase the friction brake torque command value FB * by an amount that the increase in the regenerative brake torque command value RB * is insufficient from the increase amount of the target brake torque TQ *. In other words, in this case, the increase in the target brake torque TQ * is compensated by the increase in the friction brake torque FB instead of the regenerative brake torque RB.

  Here, as long as the delay in increasing the friction brake pressure is prevented by suppressing the change in the friction brake torque command value FB * at the time of the second shift request, the increase in the target brake torque TQ * due to the additional brake pedal depression The compensation may be made not by increasing the friction brake torque FB but by increasing the regenerative brake torque RB. Thus, by increasing the proportion of the regenerative brake torque RB with respect to the target brake torque TQ *, the regenerative energy increases correspondingly, and the fuel consumption can be improved.

  In Example 2, when the brake pedal is stepped on and the target brake torque TQ * and the target deceleration Gs * increase, the restriction on the replacement amount from the friction brake torque FB to the regenerative brake torque RB is weakened, and The reference line in map 3 is changed so that the increase rate of the brake torque command value RB * increases and the decrease rate of the friction brake torque command value FB * with respect to the target brake torque TQ * increases. Thereby, the charge ratio of the regenerative brake torque RB during the brake control is increased, and the regenerative energy is increased. Specifically, the regenerative brake torque command value RB * increases between time t3 at which the target brake torque TQ * starts increasing and time t7 at which the second shift is started, compared to when the reference line is not changed. Therefore, the regenerative energy increases by the amount indicated by the hatched portion in FIG.

  Here, as in the case where the brake stroke amount S is substantially constant, the change gradient (decrease) of the friction brake torque command value FB * before and after the start t3 of the target brake torque TQ * and before and after the second shift request time t5. (Slope or increasing slope) is controlled to be gentle. For this reason, during brake control, the friction brake torque command value FB * does not change abruptly (α2 ′> α), particularly before and after t5 when the second shift request is made. Therefore, the state change of the friction brake is suppressed, and the pressure increase response of the friction brake is ensured.

(Time chart when the brake pedal is depressed)
FIG. 13 shows a case where the deviation ΔGs * of the target deceleration becomes a negative value (ΔGs * <0) because the brake pedal is depressed. In addition, when the deviation ΔGs * changes from zero to a negative value, the reference line of the map 3 is not changed, that is, the increase amount CRBInc of the regenerative braking torque command value RB * is based on the change of the deviation ΔGs *. A case where no correction is made is indicated by a broken line.

  Since the target deceleration Gs * is substantially constant from time t1 to time t3 (ΔGs * ≈0), the reference line 1 is used in the map 3 for calculating the value CRBInc. From time t2 to t3, the increase rate of the regenerative brake torque command value RB * gradually decreases, and at the same time, the decrease rate of the friction brake torque command value FB * gradually decreases (steps S40 and S44).

  From time t3 to time t7, the brake pedal is depressed, and the target deceleration deviation ΔGs * becomes a negative value (ΔGs * <0). Therefore, the reference line 3 is used in the map 3 from the time t3 to the time t6 when the second shift request is present. Since the reference line is shifted downward, the value CRBInc after the reference line change is also corrected to the negative direction side. Therefore, the increase rate of regenerative brake torque command value RB * and the decrease rate of friction brake torque command value FB * between time t3 and time t6 are smaller than when the reference line is not changed (broken line).

  From time t3 to t6, the target brake torque TQ * decreases at a substantially constant rate. On the other hand, the increase rate of the regenerative brake torque command value RB * is suppressed by changing the reference line. Therefore, even after t3 when the target brake torque TQ * starts to decrease, the decrease rate of the friction brake torque command value FB * is suppressed, and the friction brake torque command value FB * does not decrease rapidly. Therefore, the state change of the friction brake is suppressed before and after t3 when the reference line is not changed (broken line).

  Also, during the period from time t3 to t6, the amount of increase in the regenerative brake torque command value RB * and the decrease in the friction brake torque command value FB * are reduced by limiting the replacement amount to the regenerative brake torque RB using map 3. Each change gradient of rate becomes gentle. After t4 when ΔV becomes ΔV2 or less, the value CRBInc calculated based on the reference line 3 turns negative, and the regenerative brake torque command value RB * also starts decreasing.

  Further, since the vehicle speed deviation ΔV is smaller than the value ΔV3 shown in the map 3 from the time t5 to the time t6, the value CRBInc calculated using the map 3 takes a negative constant value (step S39). Therefore, the regenerative brake torque command value RB * decreases at a constant rate CRBInc, and at the same time, the friction brake torque command value FB * decreases or increases at a substantially constant rate (the reduction rate of the target brake torque TQ * is the regenerative brake torque command value). RB * decrease rate is smaller than CRBInc) (steps S40 and S44).

  Therefore, the friction brake is not switched from the sudden pressure reduction state to the pressure increase state before and after t6 when the second shift request is made. In other words, the angle α2 ″ shown in FIG. 13 is larger than the angle α ′ when the reference line is not changed (α2 ″> α ′).

  When the current vehicle speed Vcur decreases to the second shift request vehicle speed Vnext at time t6, the second shift is requested, and after t6, the regenerative brake torque RB is gradually decreased by the value CRBDec (steps S38 and S41). At the same time, the friction brake torque FB is gradually increased by the value obtained by subtracting the decrease rate of the target brake torque TQ * from the value CRBDec (step S44).

  At time t7, the decrease in the target deceleration Gs * ends and the target deceleration Gs * becomes substantially constant (ΔGs * ≈0). When the reduction of the regenerative brake torque RB and the increase of the friction brake torque FB are completed at time t8, the second shift is started.

(Function and effect when the brake pedal is depressed)
During brake control, if the target brake torque TQ * decreases when the brake pedal is stepped back, the amount of replacement with the regenerative brake torque RB is limited to gradually decrease the decreasing gradient of the friction brake torque command value FB *. Even when the control is performed, there is a possibility that the state change of the friction brake cannot be sufficiently suppressed. That is, in this case, as indicated by the broken line (angle α ′) in FIG. 13, the decrease gradient of the friction brake torque command value FB * immediately before the second shift request time t6 may not be sufficiently reduced.

  In the second embodiment, when the brake pedal is depressed, the friction brake torque FB is replaced with the regenerative brake torque RB by changing the reference line of the map 3 to the lower reference line 3 (negative direction side). The amount limit is increased, the increase rate CRBInc of the regenerative brake torque command value RB * is decreased, and the decrease rate of the friction brake torque FB with respect to the target brake torque TQ * is decreased. Further, immediately before t6 when the second speed change request is made, the value CRBInc is set to a negative value to decrease the regenerative brake torque command value RB *. Therefore, as in the case where the brake stroke amount S is substantially constant, the change gradient (decreasing gradient or increasing gradient) of the friction brake torque command value FB * becomes gentle before and after the second shift request time t6.

  For this reason, compared with the case where the reference line is not changed (broken line), the friction brake torque command value FB * does not change abruptly from decrease to increase (α2 ″> α ′). This suppresses the pressure increase response of the friction brake.

  Note that, similarly to the first embodiment, the friction brake torque command value FB * may be maintained for a predetermined time after t6 when the second shift request is made. In this case, since the time for holding the regenerative brake torque RB is substantially lengthened, the amount of accumulated regenerative energy increases as in the first embodiment, and the fuel efficiency can be improved by that amount.

[Effect of Example 2]
The brake control device according to the second embodiment can obtain the effects listed below.

  (1) The vehicle deceleration reduction preventing means (the parts 11 to 19 of the brake controller 1 and the parts 21 to 25 of the AT controller 2) according to the second embodiment performs the third control during the third control after the end of the first shift. Until the shift of 2 is required, the amount of change per hour in the friction brake torque command value FB * is gradually corrected by correcting the amount of change in the regenerative brake torque command value RB * so as to gradually decrease. The regenerative brake torque target value correction means (command value correction unit 16a, steps S39, S40, etc.) to be reduced is provided.

  That is, the regenerative brake torque command value calculation unit 15 of the brake control device of the second embodiment uses the map 3 to calculate the command value correction that calculates the increase amount CRBInc of the regenerative brake torque command value RB * based on the vehicle speed deviation ΔV. It has decided to have the part 15a. As shown in FIG. 11, the friction brake at t4 is gradually reduced by gradually decreasing the decreasing gradient of the friction brake torque command value FB * until t4 when the second shift request is made after t1 when the first shift is completed. Relieve pressure state change. As a result, the friction brake pressure increase delay at the time of the second shift request (immediately after t4) is prevented. Therefore, the vehicle deceleration Gs requested by the driver can be satisfied regardless of the length of time until the second shift request is made after the completion of the first shift. In addition, after t4 when the second shift request is made, the time until t5 at which the second shift can actually be started is shortened, so that the responsiveness of the shift is good.

  (2) The regenerative brake torque target value correcting means sets a large amount of change per time of the regenerative brake torque command value RB * when the target deceleration Gs * increases due to an increase in the driver's brake depression.

  That is, the command value correction unit 15a changes the reference line of the map 3 according to the target deceleration deviation ΔGs *, and when the target deceleration deviation ΔGs * is a positive value (ΔGs *> 0), the upper side, that is, the positive direction side I decided to shift it. By changing the reference line in this way, when the brake pedal is stepped on and the target deceleration Gs * increases, the amount of change per hour in the regenerative brake torque command value RB * (corresponding to CRBInc) Is set large over the entire region (ΔV) until there is a shift request. Thereby, during brake control, it has the effect that the charge ratio of the regenerative brake torque RB can be increased and the regenerative energy can be increased while ensuring the pressure increase response of the friction brake.

  (3) The regenerative brake torque target value correcting means sets the target value by setting the amount of change per hour of the regenerative brake torque command value RB * to be small when the target deceleration Gs * is reduced by the driver's brake depressing. The amount of change per hour in the friction brake torque command value FB * with respect to the brake torque TQ * is set to be small.

  That is, the command value correction unit 15a changes the reference line of the map 3 according to the target deceleration deviation ΔGs *, and when the target deceleration deviation ΔGs * is a negative value (ΔGs * <0), the lower side, that is, the negative direction I decided to shift it to the side. By changing the reference line in this way, when the brake pedal is depressed and the target deceleration Gs * decreases, the amount of change per hour of the regenerative brake torque command value RB * (corresponding to CRBInc) Is set to be small over the entire region (ΔV) until there is a shift request. As a result, the friction brake torque command value FB * does not change abruptly from decrease to increase, the state change of the friction brake is suppressed, and the pressure increase response of the friction brake is ensured. Therefore, the vehicle deceleration Gs requested by the driver can be satisfied.

  The brake control device according to the third embodiment starts the switching from the regenerative brake to the friction brake at a timing earlier than the second shift request after the completion of the first shift, so that the friction brake at the time of the second shift request is changed. Prevent pressure increase delay.

[Configuration of Example 3]
The configuration of the brake control device of the third embodiment is the same as that of the first embodiment (see FIGS. 1 and 2).

  The regenerative brake torque command value calculation unit 16 according to the third embodiment includes a friction brake necessary pressure increase gradient estimation unit 16b (not shown). The regenerative brake torque command value calculation unit 16 calculates a regenerative brake torque command value RB * based on the estimation result of the friction brake necessary pressure increase gradient estimation unit 16b.

[Operation of Example 3]
Hereinafter, in the vehicle of the third embodiment, the brake control will be described while the driver is stepping on the brake pedal to apply the braking force. FIG. 14 is a flowchart showing the flow of control. This calculation is repeatedly executed every predetermined time.

  Steps S71 to S74 are the same as steps S1 to S4 of the first embodiment (see FIG. 5).

  Step S75 is the same as step S6 of the first embodiment, and calculates the maximum regenerative torque RBmax. Thereafter, the process proceeds to step S76.

  Steps S76 to S79 are the same as steps S8 to S11 of the first embodiment, and the time Tnext until the next shift request is calculated. Thereafter, the process proceeds to step S80.

  In step S80, by adding a predetermined time Cftdelay to the time Tnext until the next shift request, the time Tfbnext until the timing at which the switching from the regenerative brake to the friction brake (the increase in the friction brake) has to be completed is calculated. Specifically, Tfbnext = Tnext + Cftdelay is calculated. Further, the time Tfbnext is divided by the control period (ms) to be converted into the number of control periods. Thereafter, the process proceeds to step S81.

  The predetermined time Cftdelay is a component that compensates for the time from when the next shift is requested until the next shift is actually started. For example, the predetermined time Cftdelay is necessary for the precharge control of the frictional engagement element of the automatic transmission AT. It corresponds to time etc.

  In step S81, the friction brake necessary pressure increase gradient Degpinc is estimated. That is, the increase gradient (increase step) of the friction brake torque command value FB * in each control cycle is estimated so that the friction brake pressure increase can be completed within the required time Tfbnext until the switching to the friction brake is completed. Specifically, based on the regenerative braking torque command value RB * (n−1) in the previous control cycle and the converted request time Tfbnext, the estimation is performed using Degpinc = RB * (n−1) / Tfbnext. Thereafter, the process proceeds to step S82.

  Note that the regenerative brake torque command value RB * (n-1) in the previous control cycle and the regenerative brake torque command value RB * in the current control cycle can be approximated to each other.

  In step S82, as in step S5 of the first embodiment, the presence / absence of a shift request from the AT controller 2 is detected. If there is no shift request, the process proceeds to step S83. If there is a shift request, the process proceeds to step S85.

(When there is no shift request)
Steps S83, S84, and S87 to S90 show the flow of calculating the friction brake torque command value FB * when there is no shift request.

  In step S83, as in step S7 of the first embodiment, it is determined whether the regenerative braking torque RB has finished increasing. When it is determined that the boosting is not completed, the process proceeds to step S84, and when it is determined that the boosting is completed, the process proceeds to step S89.

(When regenerative braking torque has been increased)
In steps S89 and S90, the regenerative brake torque command value RB * (RB * = RBmax) and the friction brake torque command value FB * (FB * = TQ * −RB *) are obtained as in steps S13 and S14 of the first embodiment. calculate. Thereafter, the process proceeds to step S91.

(When regenerative braking torque has not been increased)
In step S84, it is determined whether or not it is necessary to switch from reducing the friction brake to increasing, that is, switching from decreasing to increasing friction brake torque command value FB *. Specifically, when the estimated friction brake necessary pressure increase gradient Degpinc is less than the predetermined gradient Cdegpinc, it is determined that switching is unnecessary, and the process proceeds to step S87. On the other hand, when the gradient Degpinc matches the predetermined gradient Cdegpinc, it is determined that switching is necessary, and the process proceeds to step S85.

  Here, when the predetermined gradient Cdegpinc is switched from the friction brake reduction to the increase (at the above-mentioned gradient Cdegpinc), the pressure increase delay of the friction brake actuator FBAtr is suppressed, and the vehicle deceleration Gs becomes the target deceleration Gs *. On the other hand, the range is set so as not to be insufficient (see FIG. 15).

(If switching is necessary)
In step S85, the regenerative brake torque command value RB * is decreased from the previous calculated value RB * (n-1) by the friction brake necessary pressure increase gradient Degpinc (RB * = RB * (n-1) -Degpinc). Thereafter, the process proceeds to step S86.

  In step S86, the friction brake torque command value FB * is calculated by FB * = TQ * −RB * as in step S14 of the first embodiment. Thereafter, the process proceeds to step S91.

(When switching is unnecessary)
In step S87, as in step S15 of the first embodiment, the regenerative brake torque command value RB * is increased by a predetermined value CRBInc from the previous calculated value RB * (n-1) (RB * = RB * (n- 1) + CRBInc). Thereafter, the process proceeds to step S88.

  In step S88, as in step S86, after calculating the friction brake torque command value FB *, the process proceeds to step S91.

  In steps S91 and S92, similar to steps S21 and S22 of the first embodiment, the regenerative brake torque command value RB * and the friction brake torque command value FB * are output, and the current control cycle ends.

(Time chart)
FIG. 15 is a time chart showing the brake control of the third embodiment in comparison with the prior art.

  At time t1, the first shift is completed. At time t4, the second shift is started. Brake control is performed between time t1 and time t4 when no speed change is performed.

  At time t1, the first shift (4 → 3 shift) is completed, and the brake control is started. From time t1 to t2, the predetermined gradient Cdegpinc is larger than the friction brake necessary pressure increase gradient Degpinc, so that the regenerative brake torque RB is gradually increased by a predetermined value CRBInc for each control cycle (steps S82 to S84, S87, S91). At the same time, the friction brake torque FB is gradually decreased by a predetermined value CRBInc for each control cycle (steps S88 and S92).

  At time t2, the friction brake necessary pressure increase gradient Degpinc matches the predetermined gradient Cdegpinc, so that the friction brake is switched from decelerating to increasing, that is, the friction brake torque command value FB * is decreased to increased. That is, after time t2, the regenerative brake torque RB is gradually decreased by the above gradient Degpinc (= Cdegpinc) every control cycle (steps S84, S85, S91). At the same time, the friction brake torque FB is gradually increased by the above-described gradient Degpinc (= Cdegpinc) for each control cycle (steps S86 and S92).

  When the current vehicle speed Vcur decreases to the second shift request vehicle speed Vnext at time t3, the second shift is requested (step S82). When there is a second speed change request, the regenerative brake torque RB is gradually reduced by the above gradient Degpinc (= Cdegpinc) every control cycle (steps S85 and S91), as in the case before t3. At the same time, the friction brake torque FB is gradually increased by the above-described gradient Degpinc (= Cdegpinc) for each control cycle (steps S86 and S92).

  At time t4, the regenerative brake torque RB becomes zero and the reduction of the regenerative brake torque RB is completed. At the same time, the friction brake torque FB becomes the target brake torque TQ *, and the increase of the friction brake torque FB is completed. Thus, when the switching from the regenerative brake to the friction brake is completed, the second shift is started.

(Operational effect of the first embodiment in comparison with the prior art)
The brake control device according to the third embodiment switches the friction brake from reduction to increase at t2 at a timing earlier than t3 at which the second shift request is made after t1 when the first shift is completed. By starting the switching to, the friction brake pressure increase delay during brake control is prevented.

  That is, the required time Tfbnext from the completion of the first shift to the completion of switching from the regenerative brake to the friction brake is calculated, and the necessary pressure increase gradient Degpinc of the friction brake is estimated. Further, a predetermined pressure increase gradient Cdegpinc is provided, and the friction brake torque command value FB * is increased by a predetermined gradient Degpinc = Cdegpinc from time t2 when Degpinc comes to coincide with Cdegpinc.

  Therefore, the friction brake is not suddenly switched from the reduced pressure state to the increased pressure state before and after the switching time t2 from the reduction to the increase of the friction brake. That is, as described above, since the predetermined gradient Cdegpinc is set to be sufficiently small within the predetermined range, the slope of the straight line indicating the time change of the friction brake torque command value FB * is around t2, on the right side of FIG. Slowly changes from shoulder rise (decompression) to shoulder fall (pressure increase). Therefore, the angle α3 shown in FIG. 15 is larger than the conventional technology (α3> α).

  For this reason, after t2, the delay in pressure increase of the friction brake actuator FBatr with respect to the friction brake torque command value FB * is suppressed, regardless of the length of time Tnext until the second shift request is made after the completion of the first shift. Thus, a situation where the vehicle deceleration Gs is insufficient with respect to the target deceleration Gs * requested by the driver is prevented.

(Supplementary explanation)
In the prior art, when strong deceleration is required, that is, when the brake stroke amount S is large and the target deceleration Gs * is large, the first shift is completed and the friction brake is being switched to the regenerative brake. When the second shift request is made, there is a risk that the pressure increase delay of the friction brake may occur.

  In the brake control device of the third embodiment, the required time Tfbnext until the switching from the regenerative brake to the friction brake is completed is calculated based on the target deceleration Gs * (Tnext = ΔV / Gs *, Tfbnext = Tnext + Cftdelay). When the target deceleration Gs * is large, the calculated Tfbnext is decreased by that amount, and the estimated pressure increase gradient Degpinc is increased (Degpinc = RB * (n−1) / Tfbnext). Therefore, the larger the target deceleration Gs *, the shorter the time until t2 when Degpinc coincides with the predetermined gradient Cdegpinc, and the timing at which the friction brake torque FB starts to increase increases accordingly. In other words, even when the target deceleration Gs * is large and the time Tnext until the second shift request is made is short, the pressure increase gradient at the time t2 when the friction brake torque FB starts to increase can be gradually reduced. Therefore, a situation where the actual vehicle deceleration Gs is insufficient with respect to the target deceleration Gs * requested by the driver is prevented regardless of the magnitude of the target deceleration Gs *.

  Note that the magnitude of the predetermined gradient Cdegpinc is set by balancing the improvement of fuel efficiency and effective prevention of vehicle deceleration shortage, similar to the length of the predetermined holding time Chold of the first embodiment.

  In the prior art, the higher the regenerative brake torque RB (the smaller the friction brake torque FB) is, the more the regenerative brake torque RB at time t3 when switching from the regenerative brake to the friction brake and starting the friction brake pressure increase, the pressure increase of the friction brake after t3 The gradient increases (angle α decreases). For this reason, the pressure increase delay of the friction brake is likely to occur.

  In the brake control device according to the third embodiment, the estimated pressure increase gradient Decginc increases as the regenerative brake torque command value RB * increases (Degpinc = RB * (n−1) / Tfbnext). Therefore, the time until t2 when Degpinc coincides with the predetermined gradient Cdegpinc is shortened, and the timing to start increasing the friction brake torque FB is advanced accordingly. In other words, there is no risk of starting to increase the friction brake when the regenerative brake torque RB becomes unnecessarily large after the completion of the first shift, and the pressure increase gradient at t2 when the friction brake torque FB starts to increase is always increased. Can be relaxed (α3> α). Therefore, a situation where the actual vehicle deceleration Gs is insufficient with respect to the target deceleration Gs * requested by the driver is prevented.

  For example, when the shift position of the automatic transmission AT is on the low speed side and the gear ratio (reduction ratio) Gratio is large, the regenerative brake torque RB output at the tire end is on the high speed stage side and the gear ratio Larger than when Gratio is small. Even when regenerative torque of the same magnitude is output to the output shaft of the motor generator MG, the output speed of the motor generator MG (the input speed to the automatic transmission AT) is lower at the low speed stage than at the high speed stage. (On the other hand, the output rotation speed at the tire end (the output rotation speed of the automatic transmission AT) is the same).

  Therefore, in the prior art, for example, the regenerative braking torque RB at the tire end is larger when the first shift is a 3 → 2 shift than when the first shift is a 4 → 3 shift. Therefore, the larger the gear ratio Gratio, the greater the regenerative brake torque RB at the time t3 when switching from the regenerative brake to the friction brake, and the pressure increase delay of the friction brake is likely to occur as described above.

  In the brake control device of the third embodiment, the boost start timing t2 of the friction brake torque FB is determined based on the comparison between the estimated pressure increase gradient Degpinc and the predetermined gradient Cdegpinc. As the gear ratio Gratio increases, the regenerative brake torque RB increases. However, as described above, the larger the regenerative brake torque command value RB *, the greater the estimate of Degpinc (Degpinc = RB * (n-1) / Tfbnext). When the regenerative brake torque RB becomes unnecessarily large, there is no risk of starting the friction brake boosting, and the pressure increase gradient at the time t2 when the friction brake torque FB starts to increase can be made gentle (α3> α). Therefore, a situation where the actual vehicle deceleration Gs is insufficient with respect to the target deceleration Gs * requested by the driver is prevented.

[Effect of Example 3]
The brake control device according to the third embodiment can obtain the effects listed below.

  (1) The vehicle deceleration lowering prevention means (the parts 11 to 19 of the brake controller 1 and the parts 21 to 25 of the AT controller 2) of the third embodiment performs the third control during the third control after the end of the first shift. Friction brake torque switching start control means (steps S80, S81, S84 to S86, etc.) for switching the friction brake torque command value FB * from decrease to increase at a predetermined time before the second shift is required; did.

  That is, the regenerative brake torque command value calculation unit 15 of the brake control device according to the third embodiment calculates the required time Tfbnext until the switching from the regenerative brake to the friction brake is completed, and the friction brake torque FB is calculated based on the required time Tfbnext. The friction brake necessary pressure increase gradient estimation unit 16b for estimating the pressure increase gradient Degpinc is provided. Further, the regenerative brake torque command value calculation unit 15 determines the timing to start increasing the friction brake torque FB based on the estimated gradient Degpinc. A predetermined pressure increase gradient Cdegpinc is provided, and the friction brake torque command value FB * is increased at a predetermined gradient Degpinc = Cdegpinc from time t2 when Degpinc comes to coincide with Cdegpinc. Thus, the friction brake is not suddenly switched from the reduced pressure state to the increased pressure state before and after the time t2 when the friction brake is reduced to increased. For this reason, after t2, the delay in pressure increase of the friction brake actuator FBatr with respect to the friction brake torque command value FB * is suppressed, regardless of the length of time Tnext until the second shift request is made after the completion of the first shift. The vehicle deceleration Gs requested by the driver can be satisfied.

  (2) The friction brake torque switching start control means advances the time for starting the switching from the decrease to the increase in the friction brake torque command value FB * as the target deceleration Gs * increases (steps S79 to S81). etc).

  That is, the required time Tfbnext until the switching from the regenerative brake to the friction brake is completed is calculated based on the target deceleration Gs * (Tnext = ΔV / Gs *, Tfbnext = Tnext + Cftdelay). When the brake stroke amount S is large and the target deceleration Gs * is large, the calculated Tfbnext is decreased by that amount, and the estimated pressure increase gradient Degpinc is increased (Degpinc = RB * (n−1) / Tfbnext). Therefore, the larger the target deceleration Gs *, the shorter the time until t2 when Degpinc coincides with the predetermined gradient Cdegpinc, and the timing at which the friction brake torque FB starts to increase increases accordingly. In other words, even when the target deceleration Gs * is large and the time until the second shift request is made is short, the pressure increase gradient at the time t2 when the friction brake torque FB starts to increase can be gradually reduced. Therefore, the vehicle deceleration Gs required by the driver can be satisfied regardless of the target deceleration Gs *.

  (3) The friction brake torque switching start control means advances the time for starting switching from decrease to increase of the friction brake torque command value FB * as the regenerative brake torque command value RB * increases (step S81). etc).

  That is, the larger the regenerative braking torque command value RB * is, the larger the estimated pressure increase gradient Degpinc is (Degpinc = RB * (n−1) / Tfbnext). Therefore, the larger the regenerative brake torque command value RB *, the shorter the time until t2 at which Decgpinc matches the predetermined gradient Cdegpinc, and the timing for starting to increase the friction brake torque FB is advanced accordingly. In other words, the pressure increase gradient at the time t2 when the friction brake torque FB starts to increase can be made gentle (α3> α). Therefore, the vehicle deceleration Gs requested by the driver can be satisfied.

  (4) The friction brake torque switching start control means advances the time to start switching from decreasing to increasing friction brake torque command value FB * as the reduction ratio (gear ratio) of automatic transmission AT increases. (Step S81, etc.).

  Therefore, even when the gear ratio Gratio is large so that the regenerative brake torque command value RB * becomes large, the pressure increase gradient at the time t2 when the friction brake torque FB starts to increase can be moderated (α3> α ). Therefore, the vehicle deceleration Gs requested by the driver can be satisfied.

  As mentioned above, although the brake control apparatus of this invention has been demonstrated based on Example 1 thru | or 3, it is not restricted to these Examples about a concrete structure, Invention which concerns on each claim of a claim Design changes and additions are permitted without departing from the gist of the present invention.

  For example, in the first to third embodiments, the configuration in which the brake control device of the present invention is applied to a vehicle having a stepped automatic transmission as an automatic transmission is shown. However, a belt type continuously variable transmission CVT with a manual mode is shown. The brake control device of the present invention may be applied to a vehicle equipped with the above. In these belt-type continuously variable transmissions CVT, etc., the gear ratio is changed stepwise (shifting by different stepwise steps), and a shift can be requested during regenerative cooperative brake control. is there.

1 is a schematic system diagram of a rear wheel drive vehicle to which a brake control device of the present invention is applied. It is a block diagram which shows the structure of the brake controller and AT controller of this invention. It is a shift map of the automatic transmission of the present invention. It is a map used for target deceleration calculation in the target deceleration calculation part of this invention. 3 is a main flowchart showing a flow of brake control according to the first embodiment. 6 is a sub-flowchart showing a flow of calculating maximum regenerative torque in the brake control according to the first embodiment. 3 is a sub-flowchart showing a flow of calculating a maximum regenerative torque on the regenerative unit side in the brake control of the first embodiment. It is the time chart which showed brake control of Example 1 in contrast with the prior art. It is the graph which showed the experimental result of the friction brake responsiveness of Example 1 compared with the prior art. 7 is a main flowchart showing a flow of brake control in Embodiment 2. It is the time chart which showed the brake control (when brake stroke amount is substantially constant) of Example 2 in contrast with the prior art. It is the time chart which showed brake control (when a brake pedal is stepped on) of Example 2 in contrast with before amendment. It is the time chart which showed brake control (when a brake pedal is stepped back) of Example 2 in contrast with before correction. 12 is a main flowchart illustrating a flow of brake control according to the third embodiment. It is the time chart which showed the brake control of Example 3 in contrast with the prior art.

Explanation of symbols

MG motor generator
F / D final gear differential
DSL left drive shaft
DSR right drive shaft
RL Left rear wheel (drive wheel)
RR Right rear wheel (drive wheel)
FBatr friction brake actuator 1 brake controller 2 AT controller 11 target deceleration calculation unit 12 target brake torque calculation unit 13 shift request calculation unit 14 maximum regenerative torque calculation unit 15 next shift request time calculation unit 16 regenerative brake torque command value calculation unit 17 Friction brake torque command value calculation unit 18 Regenerative brake torque boost completion determination unit 19 Shift permission determination unit 21 Current vehicle speed detection unit 22 Next shift request vehicle speed calculation unit 23 Current shift position detection unit 24 Next shift position calculation unit 25 Motor rotation speed detection unit 31 Brake stroke sensor 32 Wheel speed sensor 34 Accelerator opening sensor 35 Vehicle speed sensor 36 Motor rotation speed sensor

Claims (11)

An automatic transmission that is interposed between the motor generator and the drive wheels, and that changes the output rotation of the motor generator by at least a second speed and transmits it to the drive wheels;
Shift control means for controlling shift by the automatic transmission;
A friction brake for generating a friction brake torque on the drive wheel by a hydraulically controlled actuator;
Regenerative brake torque control means for controlling regenerative brake torque output to the drive wheels by regenerative torque generated by the motor generator;
Friction brake torque control means for controlling the friction brake torque;
A target brake torque calculating means for calculating a target brake torque of the driving wheel that achieves a target deceleration of the vehicle according to a driver's brake operation;
When a shift is requested while the regenerative brake torque is being output to the drive wheels, the ratio of the regenerative brake torque target value to the target brake torque is decreased and the ratio of the friction brake torque target value is increased. A first control that replaces the regenerative brake torque with the friction brake torque; a second control that starts the shift after the end of the first control; and the regenerative brake torque target at the target brake torque after the end of the shift. Regenerative cooperative brake control means for increasing the value ratio and decreasing the ratio of the friction brake torque target value to replace the friction brake torque with the regenerative brake torque;
In a vehicle brake control device comprising:
A next shift request prediction means for predicting a request for the second shift during the third control after the end of the first shift;
When the regenerative cooperative brake control means is predicted to start the first control by requesting the second shift during the third control after the end of the first shift, the friction brake A vehicle brake control device comprising vehicle deceleration reduction preventing means for suppressing fluctuations in the amount of change in the friction brake torque target value per hour when the torque target value is switched from decrease to increase.   2. The vehicle brake control device according to claim 1, wherein the vehicle deceleration decrease prevention unit is in a period until the second shift is requested during the third control after the first shift is completed. A vehicle brake control device comprising friction brake torque holding means for holding the friction brake torque target value constant.   3. The vehicle brake control device according to claim 2, wherein the friction brake torque holding means advances the holding start time of the friction brake torque target value earlier as the target deceleration is larger. .   4. The vehicle brake control device according to claim 2, wherein the friction brake torque holding unit is configured to perform the second gear shift after the second gear shift is requested during the third control after the first gear shift. A brake control device for a vehicle, wherein the friction brake torque target value is maintained for a predetermined time.   2. The vehicle brake control device according to claim 1, wherein the vehicle deceleration decrease prevention unit is in a period until the second shift is requested during the third control after the first shift is completed. Regenerative brake torque target value correction means for gradually reducing the amount of change in the friction brake torque target value per hour by correcting the amount of change in the regenerative brake torque target value per hour gradually. A vehicle brake control device.   6. The vehicle brake control device according to claim 5, wherein the regenerative brake torque target value correcting means is a change amount of the regenerative brake torque target value per time when the target deceleration increases due to an increase in the driver's brake depression. The brake control device for a vehicle is characterized by setting a large value.   6. The vehicle brake control device according to claim 5, wherein the regenerative brake torque target value correcting means is a change amount per hour of the regenerative brake torque target value when the target deceleration is reduced by a driver's brake depressing. The vehicle brake control device is characterized in that the amount of change per hour of the friction brake torque target value with respect to the target brake torque is set small by setting a small value.   2. The vehicle brake control device according to claim 1, wherein the vehicle deceleration reduction preventing means is a predetermined unit before the second shift is requested during the third control after the first shift is completed. A brake control apparatus for a vehicle, comprising: friction brake torque switching start control means for switching the friction brake torque target value from decrease to increase at a time.   9. The vehicle brake control device according to claim 8, wherein the friction brake torque switching start control means advances the switching start time of the friction brake torque target value as the target deceleration increases. Brake control device.   10. The vehicle brake control device according to claim 8, wherein the friction brake torque switching start control means advances the switching start time of the friction brake torque target value as the regenerative brake torque target value increases. A vehicle brake control device. 10. The vehicle brake control device according to claim 8, wherein the friction brake torque switching start time control means advances the switching start time of the friction brake torque target value as the reduction ratio of the automatic transmission increases. A vehicle brake control device.

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