JP6337476B2 - Brake control device for vehicle - Google Patents

Description

  The present invention relates to a vehicle braking control device applied to a vehicle including a hydraulic braking device and a regenerative braking device.

  In addition to the hydraulic braking device, development of a vehicle that includes a regenerative braking device that applies a regenerative braking force to the vehicle is underway. In such a vehicle, the regenerative braking device and the hydraulic braking device may be controlled based on a required braking force corresponding to the amount of braking operation when the driver performs a braking operation. However, the response speed of the hydraulic braking device is smaller than the response speed of the regenerative braking device.

  Therefore, in such a vehicle, the operation mode of the regenerative braking device is adapted to the response speed of the hydraulic braking device. For example, in Patent Document 1, the time from the start of the braking operation by the driver to the time when the application of the regenerative braking force to the vehicle by the operation of the regenerative braking device is started, and the generation of the hydraulic braking force is the hydraulic braking device. The regenerative braking device is controlled so as to be equal to the time from when it is instructed to when the hydraulic braking force actually starts to be applied to the vehicle by the hydraulic braking device.

JP2013-158186A

  By the way, in recent years, in a vehicle in which regenerative braking force and hydraulic braking force are coordinated, there is a desire to increase the response speed when increasing the braking force of the entire vehicle as the required braking force increases.

  An object of the present invention is to provide a vehicle braking control device capable of increasing the response speed of the braking force applied to the entire vehicle when the required braking force for the vehicle is increased.

  A vehicle braking control device for solving the above-described problems is provided with a regenerative braking device that applies a regenerative braking force to a vehicle, and a hydraulic pressure in a wheel cylinder that is provided for a wheel, thereby adjusting the fluid pressure to the vehicle. It is an apparatus applied to a vehicle provided with a hydraulic braking device that applies pressure braking force. The braking control device performs a correction process for increasing the regenerative braking force applied to the vehicle by the regenerative braking device when the hydraulic braking force is increased with an increase in the required braking force required for the vehicle. A correction control unit is provided.

  In general, the response speed of the regenerative braking force applied to the vehicle by the regenerative braking device is larger than the response speed of the hydraulic braking force applied to the vehicle by the hydraulic braking device. According to the above configuration, when the hydraulic braking force is increased as the required braking force is increased, the correction process is performed to compensate for the response delay of the hydraulic braking force, and the regenerative braking force is increased. As a result, the time lag between the increase start of the required braking force and the increase start of the braking force applied to the entire vehicle is shortened as compared with the case where the correction process is not performed. Therefore, the response speed of the braking force applied to the entire vehicle when the required braking force on the vehicle is increased can be increased.

  Incidentally, the response speed of the hydraulic braking force based on the operation of the hydraulic braking device may be small or large. Therefore, even when the increase mode of the required braking force is equivalent, the variation mode of the braking force difference, which is a difference obtained by subtracting the hydraulic braking force actually applied to the vehicle by the hydraulic braking device from the required braking force. Is a mode corresponding to the response speed of the hydraulic braking force at that time. Therefore, in the vehicle braking control apparatus, it is preferable that the correction control unit increase the amount of increase in the regenerative braking force accompanying the execution of the correction process as the braking force difference increases. According to this configuration, the increase amount of the regenerative braking force accompanying the execution of the correction process can be determined to an amount corresponding to the response speed of the hydraulic braking force. As a result, when the required braking force is increased, the difference between the required braking force and the braking force of the entire vehicle can be further reduced.

  The vehicle braking control device is configured such that a difference between a required hydraulic braking force, which is a required value for the hydraulic braking device, and a hydraulic braking force applied to the vehicle by the hydraulic braking device exceeds a dead band equivalent value. In addition, a hydraulic pressure control unit that controls the hydraulic braking device to bring the hydraulic braking force closer to the target hydraulic braking force may be provided. In this case, when the required hydraulic braking force is changed and the above difference becomes larger than the dead zone equivalent value, the hydraulic braking force approaches the target hydraulic braking force by the operation of the hydraulic braking device. Therefore, when the required hydraulic braking force is increased in a situation where the hydraulic braking force applied to the vehicle by the hydraulic braking device is greater than or equal to the required hydraulic braking force, the fluid applied to the vehicle by the hydraulic braking device. Compared to when the required hydraulic braking force is increased under a situation where the pressure braking force is less than the required hydraulic braking force, the response speed of the hydraulic braking force is reduced, and the braking force difference is likely to increase.

  In view of this, the correction control unit, when the hydraulic braking force applied to the vehicle by the hydraulic braking device is greater than or equal to the required hydraulic braking force, increases the required hydraulic braking force to the vehicle by the hydraulic braking device. Compared to when the required hydraulic braking force is increased under a situation where the applied hydraulic braking force is less than the required hydraulic braking force, the time for increasing the regenerative braking force is increased by performing the correction process. May be. In this case, correction processing is performed depending on whether or not the hydraulic braking force applied to the vehicle by the hydraulic braking device at the time when the required hydraulic braking force is increased in accordance with the increase in the required braking force. The time for increasing the regenerative braking force is adjusted by performing the above. That is, by adopting such braking control, it is possible to realize control in which the amount of increase in the regenerative braking force accompanying the execution of the correction process is increased as the braking force difference increases.

  In the vehicle brake control device, the correction control unit may end the correction process when the braking force difference becomes less than an end determination value during the execution of the correction process. According to this configuration, the correction process can be performed when the braking force difference is large.

  Further, the correction control unit may end the correction process when an increase in the hydraulic braking force applied to the vehicle is detected by the hydraulic braking device during the correction process. According to this configuration, the correction process can be terminated when the hydraulic braking force starts to increase as the required braking force increases.

  The correction control unit preferably starts the correction process when the required braking force increases in accordance with the increase in the operation amount of the brake operation member. According to this configuration, when the driver requests an increase in the vehicle deceleration, the vehicle deceleration can be quickly increased by performing the correction process. Therefore, drivability for the driver who performs the brake operation can be improved.

The block diagram which shows schematic structure of a hybrid vehicle provided with the control apparatus which is one Embodiment of the braking control apparatus of a vehicle. The graph which shows the relationship between the amount of brake fluid required in order to change a wheel cylinder pressure and a wheel cylinder pressure. The timing chart which shows transition of the wheel cylinder pressure when the increase gradient changes in the middle of increasing hydraulic braking force. The timing chart which shows transition of the wheel cylinder pressure at the time of transfering from a decreasing state to an increasing state. (A)-(c) is a timing chart which shows transition of the wheel cylinder pressure at the time of transfering from a hold | maintenance state to an increase state. The flowchart explaining the processing routine performed when the brake operation is performed by the driver | operator. The flowchart explaining the process routine performed in order to determine the correction amount. It is an example of the timing chart at the time of brake operation by a driver, (a) shows change of demand braking force, (b) shows change of effective hydraulic braking force, and (c) shows change of effective regenerative braking force. (D) shows the transition of the effective braking force. In another embodiment, the flowchart explaining a part of process routine performed when the brake operation is performed by the driver | operator.

Hereinafter, an embodiment embodying a braking control device for a vehicle will be described with reference to FIGS.
FIG. 1 illustrates a hybrid vehicle including a control device 100 that is a vehicle braking control device of the present embodiment. As shown in FIG. 1, the hybrid vehicle is provided with a hybrid system 10 and a hydraulic braking device 30 that applies a braking force (hydraulic braking force) to all the wheels WH.

  The hybrid system 10 includes an engine 11 that is operated by supplying fuel such as gasoline, and a motor generator 12 that is an example of a regenerative braking device. The motor generator 12 is connected to the crankshaft 11 a of the engine 11 through a belt 13 and an electromagnetic clutch 14. The clutch 14 is in a connected state while the vehicle is running. When the clutch 14 is in the connected state, the power output from the motor generator 12 can be transmitted to the crankshaft 11a, and the rotation of the crankshaft 11a can be transmitted to the motor generator 12.

  An automatic transmission 15 is connected to the crankshaft 11 a of the engine 11, and wheels WH are connected to the output shaft 15 a of the automatic transmission 15 through a differential 16. Therefore, the power output from at least one of the engine 11 and the motor generator 12 is transmitted to the wheel WH through the automatic transmission 15 and the differential 16.

  The motor generator 12 generates power when electric power from the battery 21 is supplied via the inverter 22. Further, the motor generator 12 can generate power by transmitting the rotation of the crankshaft 11 a through the clutch 14 and the belt 13. The electric power generated by the motor generator 12 is supplied to and stored in the battery 21 via the inverter 22. When the rotation of the wheel WH is transmitted to the motor generator 12 and the motor generator 12 is generating electric power, a regenerative braking force corresponding to the amount of power generation is applied to the wheel WH.

  The hydraulic braking device 30 is a so-called by-wire hydraulic braking device. That is, the hydraulic braking device 30 includes a hydraulic pressure generating device 32 to which a brake pedal 31 as an example of a brake operation member is drivingly connected, and a liquid in a wheel cylinder 36 of a brake mechanism 35 provided for each wheel WH. And a brake actuator 33 for adjusting a wheel cylinder pressure (hereinafter also referred to as “WC pressure”). Further, the hydraulic braking device 30 is provided with a brake operation amount detection sensor SE1 that detects an operation amount of the brake pedal 31.

  Such a hydraulic braking device 30 has a supply pump that operates to supply brake fluid into a wheel cylinder 36 of a brake mechanism 35 provided for each wheel WH. The hydraulic braking device 30 includes a valve for adjusting the inflow speed of the brake fluid into the wheel cylinder 36, a valve for adjusting the outflow speed of the brake fluid from the inside of the wheel cylinder 36, and the like. .

  The brake mechanism 35 includes a rotating body (for example, a disk) that rotates integrally with the wheel WH, and a friction material (for example, a brake pad) supported by the vehicle body. Then, the friction material is pressed against the rotating body with a force corresponding to a wheel cylinder pressure (hereinafter also referred to as “WC pressure”) which is a hydraulic pressure in the wheel cylinder 36. In other words, the brake mechanism 35 applies a hydraulic braking force corresponding to the WC pressure to the wheel WH. In the present embodiment, when the hydraulic braking force is applied to the vehicle during the braking operation by the driver, the WC pressure in each wheel cylinder 36 is substantially the same pressure.

Next, the control device 100 will be described.
In addition to the brake operation amount detection sensor SE1, the control device 100 includes an accelerator opening sensor SE2 that detects the operation amount of the accelerator pedal 17 by the driver, a vehicle speed sensor SE3 that detects the vehicle body speed of the vehicle, and an acceleration in the longitudinal direction of the vehicle. An acceleration sensor SE4 for detecting longitudinal acceleration is electrically connected. Such a control device 100 includes a power management computer 101, a power train control unit 102, a motor control unit 103, and a brake control unit 104. The power train control unit 102 controls the power train PT having the engine 11, the automatic transmission 15 and the clutch 14. The motor control unit 103 controls the motor generator 12, and the brake control unit 104 controls the hydraulic braking device 30.

  When the driver performs an accelerator operation, the power management computer 101 calculates the required power required for the engine 11 and the required power required for the motor generator 12 based on the running state of the vehicle. When the power management computer 101 determines that the battery 21 needs to be charged, the power management computer 101 requires the power required for the engine 11 and the power generation amount required by the motor generator 12 so that the motor generator 12 generates power using the power from the engine 11. The required power generation amount is calculated. Then, the power management computer 101 transmits a control command based on the required power to the power train control unit 102, or transmits a control command based on the required power or the required power generation amount to the motor control unit 103.

  Further, the power management computer 101 calculates the maximum value BPR_Max of the regenerative braking force that can be applied to the vehicle at that time based on the charged amount of the battery 21 and the vehicle body speed at that time. Then, the power management computer 101 transmits the calculated maximum value BPR_Max of the regenerative braking force at that time to the brake control unit 104.

  The power management computer 101 receives information related to the required regenerative braking force BPRT calculated by the brake control unit 104 when the vehicle decelerates due to the brake operation by the driver. Then, the power management computer 101 transmits the received information to the motor control unit 103.

  The motor control unit 103 receives information related to the required regenerative braking force BPRT from the power management computer 101 when the vehicle decelerates due to the brake operation by the driver. Then, the motor control unit 103 causes the motor generator 12 to generate power so that a regenerative braking force equivalent to the required regenerative braking force BPRT based on the received information is applied to the vehicle. The regenerative braking force actually applied to the vehicle by the motor generator 12 in this way is referred to as “executed regenerative braking force BPR”.

  When the driver performs a brake operation, the brake control unit 104 calculates a required braking force BPT for the vehicle requested by the driver based on the brake operation amount detected by the brake operation amount detection sensor SE1. At this time, the required braking force BPT is increased as the brake operation amount is increased. The brake control unit 104 calculates a target hydraulic braking force BPPT, which is a required hydraulic braking force, according to the calculated required braking force BPT. Then, the brake control unit 104 controls the hydraulic braking device 30 based on the target hydraulic braking force BPPT.

  Further, the brake control unit 104 calculates a required regenerative braking force BPRT. For example, when the hydraulic braking force actually applied to the vehicle by the hydraulic braking device 30 is “effective hydraulic braking force BPP”, the brake control unit 104 subtracts the effective hydraulic braking force BPP from the required braking force BPT. The required regenerative braking force BPRT is increased as the braking force difference BP_Sub, which is the difference, is increased. Then, the brake control unit 104 transmits information regarding the calculated required regenerative braking force BPRT to the power management computer 101.

  Here, the response speed of the effective hydraulic braking force BPP applied to the vehicle by the hydraulic braking device 30 is generally smaller than the response speed of the effective regenerative braking force BPR applied to the vehicle by the motor generator 12. Therefore, in this embodiment, when the brake operation by the driver is started and when the brake operation amount is increased by the driver, the response delay of the effective hydraulic braking force BPP is compensated by the effective regenerative braking force BPR. Correction processing is executed. As a result, when the required braking force BPT increases, it is possible to quickly start increasing the effective braking force BPA, which is the sum of the effective hydraulic braking force BPP and the effective regenerative braking force BPR.

  However, the response speed of the effective hydraulic braking force BPP applied to the vehicle by the hydraulic braking device 30 may vary depending on the magnitude of the WC pressure in the wheel cylinder 36 and the state before the increase of the hydraulic braking force is started. . When the response speed of the effective hydraulic braking force BPP is small, the braking force difference BP_Sub obtained by subtracting the effective hydraulic braking force BPP from the required braking force BPT is likely to be larger than when the response speed is high. Therefore, the appropriate amount of the effective braking force BPA, which is the braking force of the entire vehicle, is adjusted by adjusting the increase amount of the effective regenerative braking force BPR accompanying the execution of the correction process according to the response speed of the effective hydraulic braking force BPP at that time. Can be achieved.

A change in the response speed of the effective hydraulic braking force according to the WC pressure Pwc in the wheel cylinder 36 will be described with reference to FIG.
FIG. 2 shows the relationship between the WC pressure Pwc and the amount Y of brake fluid necessary to change (increase or decrease pressure) the WC pressure Pwc. As shown in FIG. 2, the amount Y of brake fluid required to increase the WC pressure Pwc increases as the WC pressure Pwc decreases. For example, the fluid amount for increasing the WC pressure Pwc from the eleventh fluid pressure Pwc11 to the twelfth fluid pressure Pwc12 that is higher than the eleventh fluid pressure Pwc11 by a predetermined amount ΔPwc1 is the first fluid amount ΔY1. It is. In contrast, when the WC pressure Pwc is increased from the 21st hydraulic pressure Pwc21 higher than the 12th hydraulic pressure Pwc12 to the 22nd hydraulic pressure Pwc22 higher than the 21st hydraulic pressure Pwc21 by a predetermined amount ΔPwc1. The liquid amount required for the second liquid amount ΔY2 is smaller than the first liquid amount ΔY1.

  That is, when the WC pressure Pwc is increased or decreased while the WC pressure Pwc is low, the wheel is larger than when the WC pressure Pwc is increased or decreased while the WC pressure Pwc is high. The amount of brake fluid flowing into the cylinder 36 or the amount of brake fluid flowing out of the wheel cylinder 36 increases. Therefore, the higher the WC pressure Pwc, the higher the response speed of the hydraulic braking force because the change gradient of the WC pressure Pwc tends to be steep.

With reference to FIGS. 3 to 5, a change in the response speed of the hydraulic braking force according to the state before the hydraulic braking force is increased by the operation of the hydraulic braking device 30 will be described.
First, the control of the effective hydraulic braking force BPP in accordance with the variation of the target hydraulic braking force BPPT will be described. That is, when the difference ΔBPP (= | BPPT−BPP |) between the target hydraulic braking force BPPT and the effective hydraulic braking force BPP is equal to or less than a predetermined dead band equivalent value D1, the target hydraulic braking force BPPT fluctuates (increases or decreases). Even so, the effective hydraulic braking force BPP is maintained. That is, the control dead zone DZ is set between the sum of the target hydraulic braking force BPPT and the dead zone equivalent value D1 and the difference obtained by subtracting the dead zone equivalent value D1 from the target hydraulic braking force BPPT. When the difference ΔBPP is larger than the dead band equivalent value D1, the hydraulic braking device 30 is operated to bring the effective hydraulic braking force BPP closer to the target hydraulic braking force BPPT.

  Next, with reference to FIG. 3, the case where the increase speed changes during the increase of the target hydraulic braking force BPPT will be described. As shown in FIG. 3, before the timing t21 when the increase speed is switched, the effective hydraulic braking force BPP is increased in accordance with the increase in the target hydraulic braking force BPPT within a range where the difference ΔBPP does not become the dead band equivalent value D1 or less. Will be increased. The increasing speed of the effective hydraulic braking force BPP at this time is substantially equal to the increasing speed of the target hydraulic braking force BPPT. Then, the timing t21 is reached, and the increasing speed of the target hydraulic braking force BPPT is increased. At this time, the difference ΔBPP is larger than the dead band equivalent value D1. Therefore, even if the increase speed of the target hydraulic braking force BPPT increases at the timing t21, the effective hydraulic braking force BPP is increased at a speed substantially equal to the increased speed of the target hydraulic braking force BPPT after the change.

That is, when the increase speed is changed during the increase of the target hydraulic braking force BPPT, the response speed of the effective hydraulic braking force BPP is relatively high.
Next, with reference to FIG. 4, a case will be described in which a transition is made from a decreasing state in which the target hydraulic braking force BPPT is decreased to an increasing state in which the target hydraulic braking force BPPT is increased. As shown in FIG. 4, in the reduced state up to the first timing t31, the effective hydraulic braking force BPP is slightly larger than the sum of the target hydraulic braking force BPPT and the dead zone equivalent value D1. It is reduced in accordance with the decrease in power BPPT.

  Then, when the state is shifted to the increase state at the first timing t31, the target hydraulic braking force BPPT is increased, so that the difference ΔBPP between the target hydraulic braking force BPPT and the effective hydraulic braking force BPP is equal to or less than the dead zone equivalent value D1. Become. Therefore, the effective hydraulic braking force BPP is maintained from the first timing t31. Then, at the second timing t32, the effective hydraulic braking force BPP becomes equal to the target hydraulic braking force BPPT, and at the subsequent third timing t33, the above difference is obtained in a state where the effective hydraulic braking force BPP is smaller than the target hydraulic braking force BPPT. ΔBPP becomes equal to the dead band equivalent value D1. Then, the increase of the effective hydraulic braking force BPP is started with the passage of the third timing t33.

  That is, a time lag TL is generated between the start of increase of the target hydraulic braking force BPPT (first timing t31) and the start of increase of the effective hydraulic braking force BPP (third timing t33). The response speed of the hydraulic braking force is reduced by the amount of time lag TL.

Next, with reference to FIGS. 5A, 5 </ b> B, and 5 </ b> C, a description will be given of a case where the holding state in which the target hydraulic braking force BPPT is held is shifted to the increasing state.
FIG. 5A shows the case where the target hydraulic braking force BPPT and the effective hydraulic braking force BPP are substantially equal in the holding state, that is, the case where the difference ΔBPP is substantially “0 (zero)”. In this case, even if the holding state is increased from the holding state at the first timing t41, the execution hydraulic pressure braking force BPP is held from the first timing t41 to the second timing t42 where the difference ΔBPP is equal to the dead zone equivalent value D1. Will continue. That is, the period from the first timing t41 to the second timing t42 is the time lag TL. Then, when the second timing t42 elapses, the effective hydraulic braking force BPP starts to increase.

  In this case, at the start of the increase in the target hydraulic braking force BPPT, the difference ΔBPP is small compared to the case where the decrease state shown in FIG. 4 is shifted to the increase state. Therefore, the response speed of the hydraulic braking force is greater than when shifting from the decreasing state to the increasing state.

  However, the length of the time lag TL that occurs when shifting from the holding state to the increasing state also varies depending on the magnitude relationship between the target hydraulic braking force BPPT and the effective hydraulic braking force BPP in the holding state. That is, as shown in FIG. 5B, when the execution hydraulic pressure braking force BPP is shifted from the reduced state to the holding state at the first timing t51, the effective hydraulic pressure braking force BPP is larger than the target hydraulic pressure braking force BPPT. Held in a state. Thereafter, when the holding state is shifted to the increasing state at the second timing t52, the target hydraulic braking force BPPT starts to increase, but the difference ΔBPP becomes equal to or less than the dead zone equivalent value D1, so that the effective hydraulic braking force is increased. BPP retention is continued. Then, when the difference ΔBPP becomes larger than the dead band equivalent value D1 at the third timing t53, an increase in the effective hydraulic braking force BPP is started.

  In this case, the period from the second timing t52 to the third timing t53 is the time lag TL. In this case, the time lag TL is longer than the time lag TL shown in FIG. That is, the response speed of the hydraulic braking force is smaller than that shown in FIG.

  Further, as shown in FIG. 5C, when the state is shifted from the increasing state to the holding state at the first timing t61, the effective hydraulic braking force BPP is held in a state smaller than the target hydraulic braking force BPPT. After the transition from the holding state to the increasing state at the second timing t62 thereafter, when the increase in the target hydraulic braking force BPPT is started, the difference ΔBPP is calculated from the dead band equivalent value D1 at the third timing t63 immediately after that. Also grows. Therefore, the increase in the effective hydraulic braking force BPP is started at the third timing t63.

  In this case, the period from the second timing t62 to the third timing t63 is a time lag TL. In this case, the time lag TL is more than that in the case shown in FIG. 5A and the case shown in FIG. Shorter. That is, the response speed of the hydraulic braking force is larger than the case shown in FIG. 5A and the case shown in FIG.

  Next, a processing routine executed by the brake control unit 104 when the driver operates the brake will be described with reference to a flowchart shown in FIG. This processing routine is executed for each preset control cycle.

  As shown in FIG. 6, in this processing routine, the brake control unit 104 increases the required braking force BPT as the brake operation amount detected by the brake operation amount detection sensor SE1 increases (step S11). Subsequently, the brake control unit 104 receives information on the effective regenerative braking force BPR applied to the vehicle by the motor generator 12 from the power management computer 101 (step S12). Subsequently, the brake control unit 104 sets a difference obtained by subtracting the execution regenerative braking force BPR acquired in step S12 from the required braking force BPT calculated in step S11 as the target hydraulic braking force BPPT (step S13). That is, the target hydraulic braking force BPPT tends to increase as the required braking force BPT increases, and increases as the effective regenerative braking force BPR decreases.

  Then, the brake control unit 104 controls the hydraulic braking device 30 to bring the effective hydraulic braking force BPP closer to the target hydraulic braking force BPPT calculated in step S13 (step S14). In this regard, in the present embodiment, the brake control unit 104 controls the hydraulic braking device 30 when the difference ΔBPP between the target hydraulic braking force BPPT and the effective hydraulic braking force BPP exceeds the dead zone equivalent value D1. Thus, an example of a “hydraulic pressure control unit” that makes the effective hydraulic braking force BPP approach the target hydraulic braking force BPPT is configured.

  Subsequently, the brake control unit 104 calculates the effective hydraulic braking force BPP applied to the vehicle by the hydraulic braking device 30 (step S15). Here, when a sensor for detecting the WC pressure Pwc in the wheel cylinder 36 is provided, the effective hydraulic braking force BPP can be calculated based on the WC pressure Pwc detected by the sensor. The estimated value of the hydraulic braking force estimated from the operating state of the hydraulic braking device 30 may be used as the effective hydraulic braking force BPP.

  Then, the brake control unit 104 executes a correction amount determination process for determining a correction amount ΔBPR that is an increase amount of the execution regenerative braking force BPR and a required regenerative braking force BPRT accompanying the execution of the correction process (step S16). This correction amount determination process will be described later with reference to FIG. Subsequently, the brake control unit 104 transmits information regarding the determined required regenerative braking force BPRT to the power management computer 101 (step S17). In other words, in the present embodiment, the effective regenerative braking force BPR applied to the vehicle by the motor generator 12 is increased when the effective hydraulic braking force BPP is increased with the increase in the required braking force BPT in steps S16 and S17. An example of “correction processing” is configured. The brake control unit 104 constitutes an example of a “correction control unit” that performs correction processing. Thereafter, the brake control unit 104 once ends this processing routine.

  The power management computer 101 transmits the received information on the requested regenerative braking force BPRT to the motor control unit 103. The motor control unit 103 that has received the information controls the motor generator 12 to bring the effective regenerative braking force BPR closer to the required regenerative braking force BPRT.

  Next, the correction amount determination processing routine in step S16 will be described with reference to the flowchart shown in FIG. Here, the point in time when the increase in the required braking force BPT is started is referred to as “at the time of starting braking increase”, and the effective regenerative braking force BPR at the start of increasing braking is referred to as “executed regenerative braking force BPRA at the start of increasing braking”. ". Here, “at the time of starting braking increase” includes the time when the brake operation by the driver is started and the time when the state where the brake operation amount is maintained is shifted to the state where the brake operation amount is increased. It is out.

  As shown in FIG. 7, in this processing routine, the brake control unit 104 determines whether or not the regenerative braking force BPRA at the start of braking increase is smaller than the current maximum value BPR_Max of the regenerative braking force (step). S21). When the execution regenerative braking force BPRA at the start of braking increase has already reached the maximum value BPR_Max of the regenerative braking force, the execution regenerative braking force BPR cannot be increased by performing the correction process. Therefore, when the effective regenerative braking force BPRA at the start of braking increase is equal to or greater than the maximum value BPR_Max of the regenerative braking force (step S21: NO), the brake control unit 104 sets “0 (zero)” to the correction amount ΔBPR. (Step S22), the process proceeds to Step S26 described later. Here, the “correction amount ΔBPR” indicates the amount of increase in the regenerative braking force added to the execution regenerative braking force BPRA at the start of braking increase.

  On the other hand, when the effective regenerative braking force BPRA at the start of braking increase is less than the maximum value BPR_Max of the regenerative braking force (step S21: YES), the brake control unit 104 starts increasing braking from the current maximum value BPR_Max of the regenerative braking force. The difference obtained by subtracting the effective regenerative braking force BPRA at that time is set as a correction allowable amount ΔBPR_Lim (step S23). Then, the brake control unit 104 calculates the provisional correction amount ΔBPR1 (step S24). For example, when the correction amount determined in the previous control cycle is the previous correction amount ΔBPR (n−1), the brake control unit 104 adds the previous correction amount ΔBPR (n−1) and the unit increase amount BPRUP. Is a provisional correction amount ΔBPR1. For example, the unit increase amount BPRUP is a value corresponding to the increase speed of the brake operation amount at that time, and the value increases as the increase speed increases.

  Subsequently, the brake control unit 104 sets the minimum value of the provisional correction amount ΔBPR1 and the allowable correction amount ΔBPR_Lim as the correction amount ΔBPR (step S25). That is, the correction amount ΔBPR is gradually increased within a range where the effective regenerative braking force BPR does not exceed the maximum value BPR_Max of the regenerative braking force.

  In step S26, the brake control unit 104 sets a difference obtained by subtracting the current effective hydraulic braking force BPP calculated in step S15 from the required braking force BPT calculated in step S11 as a braking force difference BP_Sub. Then, the brake control unit 104 sets the minimum value among the sum of the execution regenerative braking force BPRA and the correction amount ΔBPR at the start of braking increase and the braking force difference BP_Sub as the required regenerative braking force BPRT (step S27). . Thereafter, the brake control unit 104 ends this processing routine.

Next, with reference to the timing chart shown in FIG. 8, the action at the time of brake operation by the driver will be described.
As shown in FIGS. 8A, 8B, 8C, and 8D, when the driver starts the brake operation at the first timing t11 while the vehicle is traveling, the required braking force BPT is calculated as the brake operation amount. It gradually increases with the increase of. Then, since the brake operation amount becomes constant at the subsequent fourth timing t14, the required braking force BPT becomes constant after the fourth timing t14.

  Immediately after the start of such a brake operation, due to the response delay of the effective hydraulic braking force BPP, the effective hydraulic braking force BPP is not applied to the vehicle. In this case, the effective regenerative braking force BPRA at the start of braking increase is “0 (zero)”, which is smaller than the maximum value BPR_Max of the current regenerative braking force (step S21: YES). Therefore, the correction amount ΔBPR can be determined to a value larger than “0 (zero)” (steps S23 to S27, S17).

  That is, during the period from the first timing t11 to the third timing t13 when the effective hydraulic braking force BPP is not applied to the vehicle due to a response delay, the effective hydraulic braking force BPP is “0 (zero)” and the provisional correction amount ΔBPR1. Is equal to the increase gradient of the required braking force BPT. Moreover, the provisional correction amount ΔBPR1 is equal to or less than the allowable correction amount ΔBPR_Lim (= BPR_Max−BPRA). Therefore, during the same period, the correction amount ΔBPR gradually increases as the required braking force BPT, that is, the provisional correction amount ΔBPR1 increases. Then, the required regenerative braking force BPRT becomes equal to the required braking force BPT, and as a result, the execution regenerative braking force BPR substantially equal to the required braking force BPT is applied to the vehicle.

  When the third timing t13 is reached, the effective regenerative braking force BPR reaches the maximum value BPR_Max of the regenerative braking force. Then, since the temporary correction amount ΔBPR1 becomes larger than the correction allowable amount ΔBPR_Lim, the correction amount ΔBPR is held at the correction allowable amount ΔBPR_Lim after the third timing t13, and the required regenerative braking force BPRT is held at the correction allowable amount ΔBPR_Lim. The As a result, the effective regenerative braking force BPR is held at the maximum value BPR_Max of the regenerative braking force.

  Further, from the third timing t13, the effective hydraulic braking force BPP actually starts to increase. As a result, before the third timing t13, the effective braking force BPA is equal to the effective regenerative braking force BPR, whereas after the third timing t13, the effective braking force BPA is equal to the effective regenerative braking force BPR. It becomes equal to the sum of the hydraulic braking force BPP.

  Note that immediately after the third timing t13, since the WC pressure Pwc in the wheel cylinder 36 is low, the increasing speed of the effective hydraulic braking force BPP is relatively small. However, as the WC pressure Pwc increases, the increase speed of the effective hydraulic braking force BPP also increases. Then, at the fifth timing t15 after the fourth timing t14 when the holding of the required braking force BPT is started, the effective braking force BPA becomes substantially equal to the required braking force BPT, and after the fifth timing t15, The effective hydraulic braking force BPP is held.

  Here, in the comparative example in which the correction process is not performed, the execution regenerative braking force BPR is not applied to the vehicle, and therefore, as shown by a two-dot chain line in FIG. 5B, the sixth time after the fifth timing t15. The increase in the effective hydraulic braking force BPP is continued until timing t16. That is, even if the driver holds the brake operation amount, the period during which the effective braking force BPA continues to increase is relatively long.

  On the other hand, in the present embodiment, since the correction process is performed, the increase of the effective braking force BPA, that is, the effective hydraulic braking force BPP is finished at the fifth timing t15. That is, the period in which the increase in the effective braking force BPA is continued after the driver starts to hold the brake operation amount is shorter than in the case of the comparative example.

  Incidentally, depending on the operating state of the hydraulic braking device 30 before the start of the brake operation by the driver, as shown by a one-dot chain line in FIG. 8B, from the second timing t12 before the third timing t13. An increase in the effective hydraulic braking force BPP may actually be started. In this case, after the second timing t12, the braking force difference BP_Sub (= BPT−BPP) is set to the regenerative braking force BPRA (in this case, 0 (zero)) at the start of braking increase and the provisional correction amount ΔBPR1 (= ΔBPR). Smaller than the sum of (n-1) + BPRUP). That is, the required regenerative braking force BPRT is made equal to the braking force difference BP_Sub. As a result, after the second timing t12, as indicated by the alternate long and short dash line in FIG. 8C, the increase rate of the correction amount ΔBPR is smaller than that before the second timing t12.

As mentioned above, according to the said structure and effect | action, the effect shown below can be acquired.
(1) When the effective hydraulic braking force BPP is increased as the required braking force BPT increases, a correction process is performed to compensate for a response delay of the effective hydraulic braking force BPP, and the effective regenerative braking force BPR is increased. . As a result, the time lag between the start of increase of the required braking force BPT and the start of increase of the effective braking force BPA applied to the entire vehicle is shortened compared to the case where the correction process is not performed. Therefore, the response speed of the effective braking force BPA applied to the entire vehicle when the required braking force BPT for the vehicle is increased can be increased.

  (2) Further, after the brake operation amount becomes substantially constant by performing the correction process in this way, a period in which the increase in the effective braking force BPA is continued as compared with the case where the correction process is not performed. Becomes shorter. That is, the deceleration mode of the vehicle can be brought close to the brake operation mode by the driver, and thus drivability can be improved.

  (3) Further, depending on the state of the vehicle, only the effective regenerative braking force BPR may be increased without increasing the effective hydraulic braking force BPP due to an increase in the required braking force BPT. In the present embodiment, when the effective hydraulic braking force BPP is increased, the response delay of the effective hydraulic braking force BPP is compensated for by executing the correction process. Therefore, the increase mode of the effective braking force BPA is changed to the effective regenerative braking force BPR. It can approach to the case of increasing only. That is, it is possible to suppress variations in the deceleration mode of the vehicle, regardless of which method is selected which includes an increase in the effective hydraulic braking force BPP and a method which does not include an increase in the effective hydraulic braking force BPP. Therefore, when the brake operation amount is increased, drivability can be improved while increasing the response speed of the effective braking force BPA.

  (4) In the present embodiment, the correction amount ΔBPR, which is the increase amount of the effective regenerative braking force BPR accompanying the execution of the correction process, is the braking force difference BP_Sub, which is a difference obtained by subtracting the effective hydraulic braking force BPP from the required braking force BPT. The bigger it is, the bigger it becomes. Therefore, the effective braking force BPA, which is the sum of the effective hydraulic braking force BPP and the effective regenerative braking force BPR, can be brought close to the required braking force BPT. As a result, the deceleration mode of the vehicle can be brought close to the deceleration mode required by the driver, and thus drivability can be improved.

The above embodiment may be changed to another embodiment as described below.
In the above embodiment, the correction amount ΔBPR, which is the amount of increase in the effective regenerative braking force accompanying the execution of the correction process, is changed according to the temporary correction amount ΔBPR1, but the correction amount ΔBPR is set to a predetermined value. A value may be used. However, even in this case, when the correction allowable amount ΔBPR_Lim is less than the predetermined value, it is preferable that the correction amount ΔBPR is set as the correction allowable amount ΔBPR_Lim. Even if such a configuration is adopted, the same effects as the above (1) to (3) can be obtained.

  When the target hydraulic braking force BPPT is increased, the length of the time lag TL is predicted (see FIGS. 3 to 5), and the period during which the correction amount ΔBPR is increased by the correction process is determined based on the time lag TL. Good. In this case, the correction amount ΔBPR tends to increase as the time lag TL is predicted to be longer. Even if such a configuration is adopted, the same effect as the above (1) can be obtained. It should be noted that the effective regenerative braking force BPR may be held during vehicle braking after the above period has elapsed.

Further, the period during which the correction amount ΔBPR is increased by the start of the correction process may be a fixed period regardless of the length of the time lag TL.
The correction process may be terminated when an increase in the effective hydraulic braking force BPP applied to the vehicle by the hydraulic braking device 30 is detected. In this case, when an increase in the effective hydraulic braking force BPP is detected, the correction amount ΔBPR is gradually reduced and the effective regenerative braking force BPR is gradually decreased. Even if such a configuration is adopted, the same effect as the above (1) can be obtained.

  When the effective hydraulic braking force BPP starts to increase and it can be determined that the braking force difference BP_Sub has become smaller, the correction process may be terminated. For example, as shown in FIG. 9, after the correction amount ΔBPR is determined in the correction amount determination process (step S16), the brake control unit 104 determines that the braking force difference BP_Sub is less than the preset end determination value ΔBPTh. Whether or not (step S161). When the braking force difference BP_Sub is equal to or greater than the end determination value ΔBPTh (step S161: NO), the brake control unit 104 determines that the sum of the execution regenerative braking force BPRA and the correction amount ΔBPR at the start of braking increase, and the braking force difference BP_Sub The smaller value is set as the required regenerative braking force BPRT, and information on the required regenerative braking force BPRT is transmitted to the power management computer 101 (step S17). On the other hand, when the braking force difference BP_Sub is less than the end determination value ΔBPTh (step S161: YES), the brake control unit 104 sets “0 (zero)” to the correction amount ΔBPR (step S162). Thereafter, the brake control unit 104 calculates the smaller value of the sum of the execution regenerative braking force BPRA and the correction amount ΔBPR (= 0 (zero)) at the start of braking increase and the braking force difference BP_Sub as the required regenerative braking force. Information regarding the required regenerative braking force BPRT is transmitted to the power management computer 101 (step S17). That is, the correction process is ended when the braking force difference BP_Sub becomes less than the end determination value ΔBPTh. When such a configuration is adopted, the correction process can be performed only when the braking force difference BP_Sub is large.

  When the correction process is being performed with the increase in the required braking force BPT, when the increase rate of the required braking force BPT and the increase rate of the effective hydraulic braking force BPP can be regarded as equal, The correction process may be terminated.

  A device having a function capable of automatically applying a braking force is also known as a hydraulic braking device. In a vehicle provided with such a hydraulic braking device, when the effective hydraulic braking force BPP is increased when the required braking force BPT accompanying the automatic braking is increased, the execution is performed to compensate for the response delay of the effective hydraulic braking force BPP. Correction processing for increasing the regenerative braking force BPR may be performed. Even in such a case, the actual deceleration mode of the vehicle can be brought close to the deceleration mode along the profile defined by the braking control device.

  If the hydraulic brake device 30 is a brake device that can cooperate with the regenerative brake device, the master cylinder that generates the hydraulic pressure corresponding to the amount of brake operation and the wheel cylinder 36 are mechanically separated from each other. Instead of the device, a device in which the master cylinder and the wheel cylinder 36 communicate with each other through a liquid path may be used. Even in this case, the deviation between the start of increase of the hydraulic pressure in the master cylinder and the start of increase of the WC pressure Pwc in the wheel cylinder 36 can be compensated by performing the correction process.

  The vehicle may be a two-motor hybrid vehicle in addition to a one-motor hybrid vehicle as long as the vehicle includes the engine 11. Further, when the generator is provided as the regenerative braking device, the vehicle may be provided with only the engine 11 as a drive source.

The vehicle may be a vehicle that does not include the engine 11. For example, the vehicle may be an electric vehicle.
The brake operation member may be any other than the brake pedal 31 (for example, a brake lever) as long as it is operated by the driver.

  DESCRIPTION OF SYMBOLS 12 ... Motor generator which is an example of regenerative braking device, 30 ... Hydraulic brake device, 31 ... Brake pedal which is an example of brake operation member, 36 ... Wheel cylinder, 100 ... Control device as a braking control device, 104 ... Correction control Brake control unit, which is an example of a hydraulic pressure control unit, and WH ... wheels, BPP ... effective hydraulic braking force, BPPT ... target hydraulic braking force as required hydraulic braking force, BPR ... effective regenerative braking force, BPT ... required braking force , BP_Sub, braking force difference, D1, dead zone equivalent value, Pwc, WC pressure, ΔBPP, difference, ΔBPR, correction amount as an increase amount of regenerative braking force, ΔBPTh, end determination value.

Claims (6)

A regenerative braking device that applies regenerative braking force to the vehicle;
A vehicle braking control device applied to a vehicle, comprising: a hydraulic braking device that applies a hydraulic braking force to the vehicle by adjusting a hydraulic pressure in a wheel cylinder provided for the wheel,
When the hydraulic braking force is increased with the increase in the required braking force required for the vehicle, the regenerative braking device applies the regenerative braking device to the vehicle in order to compensate for the response delay of the increase in the hydraulic braking force with respect to the increase in the required braking force. A vehicle braking control device comprising: a correction control unit that performs a correction process for increasing the applied regenerative braking force. The correction control unit has a braking force difference, which is a difference obtained by subtracting the hydraulic braking force applied to the vehicle by the hydraulic braking device from the required braking force, based on the increase amount of the regenerative braking force accompanying the execution of the correction process. The braking control device for a vehicle according to claim 1, wherein the braking control device increases as the size increases. When the difference between the required hydraulic braking force, which is a required value for the hydraulic braking device, and the hydraulic braking force applied to the vehicle by the hydraulic braking device exceeds the dead band equivalent value, the hydraulic braking device is A hydraulic pressure control unit that controls the hydraulic braking force to approach the required hydraulic braking force;
When the required hydraulic braking force is increased in a situation where the hydraulic braking force applied to the vehicle by the hydraulic braking device is greater than or equal to the required hydraulic braking force, the correction control unit is configured to Compared to when the required hydraulic braking force is increased in a situation where the hydraulic braking force applied to the vehicle is less than the required hydraulic braking force, the time for increasing the regenerative braking force by performing the correction process is increased. The vehicle braking control device according to claim 1. In the correction control unit, during execution of the correction process, a braking force difference, which is a difference obtained by subtracting the hydraulic braking force applied to the vehicle by the hydraulic braking device from the required braking force, is less than the end determination value. The vehicle brake control device according to any one of claims 1 to 3, wherein the correction process is sometimes terminated. The correction control unit ends the correction process when an increase in the hydraulic braking force applied to the vehicle by the hydraulic braking device is detected during the correction process. The vehicle brake control device according to any one of the above. The correction control unit increases the amount of increase in regenerative braking force accompanying the execution of the correction processing as the response speed of the hydraulic braking force applied to the vehicle by the hydraulic braking device decreases. The vehicle brake control device according to any one of the above.