JP5767162B2 - Brake hydraulic pressure control device for vehicles - Google Patents

Description

  The present invention relates to a vehicle brake hydraulic pressure control device.

  Conventionally, as a vehicular brake hydraulic pressure control device that controls a braking force to be maintained when the vehicle stops, the braking force of the vehicle is maintained while the engine is automatically stopped, and the braking is performed according to the driving force when the engine is restarted. What reduces force is known (see Patent Document 1).

JP 2000-313253 A

  However, when the engine is restarted, the power supply voltage decreases due to the effect of cranking, which may affect the current value of the solenoid valve that holds the brake fluid. May result in a value (control amount).

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a vehicle brake fluid pressure control device that can maintain a brake fluid pressure with an appropriate control amount even when the power supply voltage is reduced when the engine is restarted. And

  The present invention that solves the above-described problems is a vehicle brake fluid pressure control device that can maintain a brake fluid pressure while the engine is stopped, and that determines whether or not the engine has been restarted. A completion state determination means for determining whether or not the restart of the engine has been completed, a first control amount corresponding to a brake fluid pressure necessary for maintaining the stop state of the vehicle, and the first control amount A condition that the brake fluid pressure is maintained at the second control amount and the restart is completed on the condition that the engine has been restarted. And a hydraulic pressure holding means for holding the brake hydraulic pressure with the first control amount.

  Here, the “determination of whether or not the restart has been completed” can be performed by, for example, determining whether or not the power supply voltage that is lowered when the engine is restarted has been restored normally. In addition, the “determination of whether or not the power supply voltage has been restored to the normal state” does not have to determine whether or not the output of the power supply voltage has recovered to 100%, and the output of the power supply voltage has recovered to, for example, 80%. It may be performed by determining whether or not it has been done. Further, this determination may be made using various parameters related to the recovery of the voltage value (such as engine speed as described later) in addition to the determination by looking at the voltage value.

  According to this configuration, when the engine is restarted, the brake fluid pressure is maintained by the second control amount that is larger than the first control amount. Therefore, even if the output of the power supply voltage is reduced when the engine is restarted, The brake fluid pressure can be reliably held by the large second control amount. In addition, when the restart is completed, the brake fluid pressure is maintained with the first control amount that is smaller than the second control amount, so the heat and load on the drive circuit and the like are reduced by controlling the drive circuit with a large control amount. can do.

  Further, in the above-described configuration, the completion state determination unit may be configured to determine that the restart is completed on the condition that the engine speed has reached a predetermined value or more.

  According to this, for example, when the completion of restart is determined based on the voltage value of the power supply voltage, the power supply voltage may fluctuate due to other factors and may be erroneously determined. By performing the start determination, it is possible to determine whether or not the restart is properly completed.

  In the above configuration, the storage unit stores a third control amount that is larger than the first control amount and smaller than the second control amount, and the engine restarts the hydraulic pressure holding means. Before the engine torque rises, the brake fluid pressure is maintained at the second control amount, and the engine is switched from the second control amount to the third control amount on the condition that the engine torque has risen. You may comprise so that it may switch from the said 3rd controlled variable to the said 1st controlled variable on the condition that it completed.

  According to this, since the brake fluid pressure is maintained at the third control amount smaller than the second control amount from when the engine torque rises until the restart is completed, for example, after the engine restart is started. Compared with the configuration in which the brake fluid pressure is maintained with the second control amount, the heat generation and load of the drive circuit and the like can be reduced.

  An example of the control amount is a current value supplied to a proportional solenoid valve capable of adjusting the brake fluid pressure in the wheel brake.

  According to the present invention, it is possible to maintain the brake fluid pressure with an appropriate control amount even when the power supply voltage is reduced when the engine is restarted.

1 is a configuration diagram of a vehicle including a vehicle brake hydraulic pressure control device according to a first embodiment of the present invention. It is a brake fluid pressure circuit diagram of a brake fluid pressure control device for vehicles. It is a block block diagram of a control part. It is a flowchart which shows operation | movement of a control part. It is time chart (a)-(e) which shows the change of each parameter when restarting an engine from idling stop. It is a block block diagram of the control part which concerns on 2nd Embodiment. It is a flowchart which shows operation | movement of the control part which concerns on 2nd Embodiment. It is a time chart (a)-(f) which shows the change of each parameter when restarting an engine from idling stop in 2nd Embodiment.

[First Embodiment]
Next, a first embodiment of the present invention will be described in detail with reference to the drawings as appropriate.
As shown in FIG. 1, the vehicle brake hydraulic pressure control device 100 is for appropriately controlling a braking force (brake hydraulic pressure) applied to each wheel W of the vehicle CR, and an oil passage (hydraulic pressure passage). And a hydraulic unit 10 provided with various components, and a control unit 20 for appropriately controlling various components in the hydraulic unit 10.

  Further, the control unit 20 of the vehicle brake hydraulic pressure control device 100 includes a wheel speed sensor 91 for detecting the wheel speed of the wheel W and a brake pedal sensor for detecting depression / release (ON / OFF) of the brake pedal BP. 92 and an ECU (Engine Control Unit) 93 for controlling the engine are connected. Detection results of the sensors 91 and 92 and information of the ECU 93 are output to the control unit 20.

  The control unit 20 includes, for example, a CPU, a RAM, a ROM, and an input / output circuit. Each calculation is performed based on inputs from the wheel speed sensor 91, the brake pedal sensor 92, and the ECU 93, and programs and data stored in the ROM. Control is executed by performing processing. The wheel cylinder H is a fluid that converts the brake fluid pressure generated by the master cylinder MC and the vehicle brake fluid pressure control device 100 into the operating force of the wheel brakes FR, FL, RR, RL provided on each wheel W. Each of which is connected to the hydraulic unit 10 of the vehicle brake hydraulic pressure control device 100 via a pipe.

  As shown in FIG. 2, the hydraulic unit 10 of the vehicular brake hydraulic pressure control device 100 includes a master cylinder MC that is a hydraulic pressure source that generates a brake hydraulic pressure in accordance with the pedaling force applied to the brake pedal BP by the driver, It arrange | positions between wheel brakes FR, FL, RR, RL. The hydraulic unit 10 includes a pump body 10a that is a base body having an oil passage through which brake fluid flows, a plurality of inlet valves 1 and outlet valves 2 arranged on the oil passage. The two output ports M1, M2 of the master cylinder MC are connected to the inlet port 121 of the pump body 10a, and the outlet port 122 of the pump body 10a is connected to each wheel brake FR, FL, RR, RL. In normal times, the oil passage is communicated from the inlet port 121 to the outlet port 122 in the pump body 10a, so that the depression force of the brake pedal BP is transmitted to the wheel brakes FL, RR, RL, FR. It is like that.

  Here, the oil path starting from the output port M1 leads to the wheel brake FL on the left side of the front wheel and the wheel brake RR on the right side of the rear wheel, and the oil path starting from the output port M2 is set to the wheel brake FR on the right side of the front wheel and the left side of the rear wheel. To the wheel brake RL. Hereinafter, the oil passage starting from the output port M1 is referred to as “first system”, and the oil passage starting from the output port M2 is referred to as “second system”.

  The hydraulic unit 10 is provided with two control valve means V corresponding to each wheel brake FL, RR in the first system, and similarly corresponding to each wheel brake RL, FR in the second system. Two control valve means V are provided. The hydraulic unit 10 is provided with a reservoir 3, a pump 4, an orifice 5a, a pressure regulating valve (regulator) R, and a suction valve 7 in each of the first system and the second system. The hydraulic unit 10 is provided with a common motor 9 for driving the first system pump 4 and the second system pump 4. The motor 9 is a motor capable of controlling the rotational speed. In this embodiment, the rotational speed is controlled by duty control. In the present embodiment, the pressure sensor 8 is provided only in the second system.

  In the following, the oil passages from the output ports M1 and M2 of the master cylinder MC to the respective pressure regulating valves R are referred to as “output hydraulic pressure passages A1”, and the oil from the first system pressure regulating valve R to the wheel brakes FL and RR. The oil passages from the road and the second system pressure regulating valve R to the wheel brakes RL and FR are respectively referred to as “wheel hydraulic pressure passage B”. In addition, an oil path from the output hydraulic pressure path A1 to the pump 4 is referred to as “suction hydraulic pressure path C”, an oil path from the pump 4 to the wheel hydraulic pressure path B is referred to as “discharge hydraulic pressure path D”, and The oil passage from the wheel fluid pressure passage B to the suction fluid pressure passage C is referred to as “open passage E”.

  The control valve means V is a valve that controls the flow of hydraulic pressure from the master cylinder MC or the pump 4 to the wheel brakes FL, RR, RL, FR (specifically, the wheel cylinder H). Can be increased, retained or decreased. Therefore, the control valve means V includes an inlet valve 1, an outlet valve 2, and a check valve 1a.

  The inlet valve 1 is a normally open proportional solenoid valve provided between each wheel brake FL, RR, RL, FR and the master cylinder MC, that is, in the wheel hydraulic pressure passage B. Therefore, the differential pressure upstream and downstream of the inlet valve 1 can be adjusted according to the value of the drive current flowing through the inlet valve 1.

  The outlet valve 2 is a normally closed electromagnetic valve interposed between each wheel brake FL, RR, RL, FR and each reservoir 3, that is, between the wheel hydraulic pressure path B and the release path E. The outlet valve 2 is normally closed, but is released by the control unit 20 when the wheel W is about to be locked, so that the brake fluid pressure acting on each wheel brake FL, FR, RL, RR is reduced. Relief to each reservoir 3

  The check valve 1a is connected to each inlet valve 1 in parallel. This check valve 1a is a valve that only allows the brake fluid to flow from each wheel brake FL, FR, RL, RR side to the master cylinder MC side, and when the input from the brake pedal BP is released, Even when the valve 1 is closed, inflow of brake fluid from each wheel brake FL, FR, RL, RR side to the master cylinder MC side is allowed.

  The reservoir 3 is provided in the release path E, and has a function of temporarily storing brake fluid that is released when each outlet valve 2 is opened. Further, between the reservoir 3 and the pump 4, a check valve 3a that allows only the flow of brake fluid from the reservoir 3 side to the pump 4 side is interposed.

The pump 4 is interposed between the suction hydraulic pressure path C leading to the output hydraulic pressure path A1 and the discharge hydraulic pressure path D leading to the wheel hydraulic pressure path B, and sucks the brake fluid stored in the reservoir 3 And has a function of discharging to the discharge hydraulic pressure path D. As a result, the brake fluid absorbed by the reservoir 3 can be returned to the master cylinder MC, and the brake fluid pressure is generated regardless of whether the brake pedal BP is operated, for example, and the wheel brakes FL, RR, RL, FR A braking force can be generated.
The amount of brake fluid discharged by the pump 4 depends on the rotation speed (duty ratio) of the motor 9. That is, as the rotation speed (duty ratio) of the motor 9 increases, the amount of brake fluid discharged by the pump 4 also increases.

  The orifice 5a attenuates the pulsation of the pressure of the brake fluid discharged from the pump 4.

  The pressure regulating valve R permits the flow of brake fluid from the output hydraulic pressure path A1 to the wheel hydraulic pressure path B during normal times, and increases the pressure on the wheel cylinder H side by the brake hydraulic pressure generated by the pump 4. It has a function of adjusting the pressure on the wheel hydraulic pressure path B and the wheel cylinder H side to a set value or less while blocking the flow, and includes a switching valve 6 and a check valve 6a.

  The switching valve 6 is a normally open proportional solenoid valve interposed between the output hydraulic pressure path A1 leading to the master cylinder MC and the wheel hydraulic pressure path B leading to each wheel brake FL, FR, RL, RR. . Although not shown in detail, the valve body of the switching valve 6 is urged in the valve closing direction by an electromagnetic force corresponding to the applied current, and the pressure of the wheel hydraulic pressure path B is higher than the pressure of the output hydraulic pressure path A1. When it becomes higher than a predetermined value (this predetermined value depends on the applied current), the brake fluid escapes from the wheel hydraulic pressure path B toward the output hydraulic pressure path A1, so that the wheel hydraulic pressure path B side The pressure (the brake fluid pressure in the wheel brakes FL, FR, RL, RR) is adjusted to a predetermined pressure. That is, the differential pressure between the upstream and downstream of the switching valve 6 is adjusted by arbitrarily changing the valve closing force according to the value of the drive current (indicated current value) input to the switching valve 6, and the wheel hydraulic pressure path The pressure of B can be adjusted below the set value.

  The check valve 6a is connected to each switching valve 6 in parallel. The check valve 6a is a one-way valve that allows the flow of brake fluid from the output hydraulic pressure path A1 to the wheel hydraulic pressure path B.

  The suction valve 7 is a normally closed electromagnetic valve provided in the suction fluid pressure passage C, and switches between a state in which the suction fluid pressure passage C is opened and a state in which the suction fluid pressure passage C is shut off. The suction valve 7 is opened by the control of the control unit 20 when the hydraulic pressure in each wheel brake FL, FR, RL, RR is increased by the pump 4, for example.

  The pressure sensor 8 detects the brake fluid pressure in the output fluid pressure path A1, and the detection result is input to the control unit 20.

Next, details of the control unit 20 will be described.
As shown in FIG. 3, the control unit 20 mainly controls the pressure regulating valve R (the switching valve 6) based on signals (information) input from the pressure sensor 8, the wheel speed sensor 91, the brake pedal sensor 92, and the ECU 93. By controlling the opening / closing operation, the brake fluid pressure is maintained while the engine is stopped. The control unit 20 includes a restart determination unit 21, a completion state determination unit 22, a storage unit 23, and a hydraulic pressure holding unit 24.

  The restart determination means 21 has a function of determining whether or not the engine has been restarted from the idling stop state based on information from the wheel speed sensor 91 and the ECU 93. Specifically, the restart determination means 21 is based on the information from the wheel speed sensor 91 and the ECU 93, and when the idling stop is not being performed and the restart signal for restarting the engine is input from the ECU 93. It is determined that the engine has been restarted.

  Here, whether or not idling is stopped may be determined by a known method. This determination is appropriately set based on the vehicle, for example, such that the wheel speed and the engine speed are not more than predetermined values and the ignition switch is in an ON state.

  When it is determined that the engine has been restarted, the restart determination unit 21 outputs a restart determination signal indicating that to the hydraulic pressure holding unit 24.

  The completion state determination means 22 has a function of determining whether or not the engine has been restarted. Specifically, as shown at time t7 in FIG. 5A, the completion state determination unit 22 determines that the restart of the engine has been completed on condition that the engine speed has reached a predetermined value N1 or more. It is configured as follows.

  Here, the time from when the engine restarts (time t5) until the engine speed reaches the predetermined value N1 (between times t5 and t7) and the time until the power supply voltage recovers to approximately 100% (time t5 to time t5). The interval between t7) is substantially constant regardless of temperature conditions and the like. Therefore, when it is determined that the engine has been restarted by looking at the engine speed, the power supply voltage (the voltage of the power supply that applies the voltage to the ECU 93 and the control unit 20) is restored to a normal state.

  In the present embodiment, the predetermined value N1 is set to the engine speed when the output of the power supply voltage temporarily lowered at the time of engine restart (time t5) is restored to approximately 100%. The present invention is not limited to this. For example, the predetermined value N1 may be set to the engine speed when the output of the power supply voltage that has temporarily decreased returns to approximately 80%.

  As shown in FIG. 3, when the completion state determination unit 22 determines that the restart of the engine is completed, the completion state determination unit 22 outputs a completion signal indicating the completion to the hydraulic pressure holding unit 24.

  The storage unit 23 includes a first current value I1 (see FIG. 5 (e)) as an example of a first control amount corresponding to the brake fluid pressure necessary for maintaining the stop state of the vehicle CR, and the first A second current value I2 (see FIG. 5E) as an example of a second control amount larger than the current value is stored. It should be noted that the second current value I2 is the first current value that is the actual current value (current value indicated by a broken line in FIG. 5E) flowing through the pressure regulating valve R due to the influence of the power supply voltage that temporarily decreases when the engine is restarted. Any value may be used as long as it does not fall below I1, and it is appropriately set by experiment, simulation, or the like.

  The hydraulic pressure holding unit 24 holds the brake hydraulic pressure at the second current value I2 on the condition that the engine has been restarted, and the brake hydraulic pressure on the first current value I1 on the condition that the restart is completed. It has a function to hold. Specifically, when a restart determination signal is input from the restart determination unit 21, the hydraulic pressure holding unit 24 reads the second current value I2 from the storage unit 23 and uses the second current value I2 as the instruction current. The pressure regulating valve R is controlled as a value.

  In the present embodiment, the hydraulic pressure holding means 24 is such that the engine is idling stopped and the master cylinder pressure (wheel cylinder pressure) is equal to or less than a predetermined value P1 (see time t4 in FIG. 5D). Also in this case, the second current value I2 is read from the storage unit 23, and the pressure regulating valve R is controlled using the second current value I2 as an instruction current value (time t4 in FIG. 5 (e)). reference). Here, when no current flows through the pressure regulating valve R during idling stop, the master cylinder pressure and the wheel cylinder pressure are substantially the same, so the hydraulic pressure holding means 24 causes the master cylinder pressure to be less than or equal to the predetermined value P1. Whether or not the wheel cylinder pressure has become substantially equal to or less than the predetermined value P1 is determined.

  Further, when a completion signal is input from the completion state determination unit 22, the hydraulic pressure holding unit 24 reads the first current value I1 from the storage unit 23, and uses the first current value I1 as an instruction current value to adjust the pressure regulating valve R. To control. Further, when the completion signal is input from the completion state determination unit 22, the hydraulic pressure holding unit 24 determines whether or not the driving force of the engine is stable based on the engine speed. The command current value is gradually decreased from the first current value I1. In addition, as a method for determining whether or not the driving force of the engine is stable, for example, a method for determining whether or not the amount of change in engine speed per unit time has become a predetermined value or less, or the output of the torque converter is A method for determining whether or not a certain value has been reached is mentioned.

  Next, the operation of the control unit 20 will be described in detail with reference to the flowchart of FIG. The control unit 20 repeatedly executes the flowchart of FIG.

  In the control shown in FIG. 4, the control unit 20 first determines whether or not idling is stopped (S1). If it is determined in step S1 that idling is stopped (Yes), the controller 20 determines whether or not the master cylinder pressure is equal to or less than a predetermined value P1 (S2).

  In step S2, when the master cylinder pressure is higher than the predetermined value P1 (No), the control unit 20 sets the OFF state (open state) without flowing the current to the pressure regulating valve R, and ends this control as it is. In step S2, when the master cylinder pressure is equal to or less than the predetermined value P1 (Yes), the control unit 20 sets the command current value to the second current value I2 (S4).

  After step S4, the control unit 20 determines whether or not the engine speed is equal to or greater than a predetermined value N1 (S5). In step S5, when the engine speed is less than the predetermined value N1 (No), the control unit 20 controls the pressure regulating valve R with the command current value (second current value I2) set in step S4 (S9). ).

  In step S5, when the engine speed is equal to or greater than the predetermined value N1 (Yes), the control unit 20 determines whether or not the driving force of the engine is stable (S6). In step S6, when the driving force is not stable (No), the control unit 20 switches the command current value to the first current value I1 (S7), and controls the pressure regulating valve R with this command current value. (S9).

  In step S6, when the driving force of the engine is stabilized (Yes), the control unit 20 sets the command current value to a value that is lower than the previous value by a predetermined amount (S8), and uses the command current value to adjust the pressure regulating valve R. Is controlled (S9).

  In step S1, when the idling is not stopped (No), the control unit 20 determines whether or not it is a restart time (whether or not the restart is started) (S11). In step S11, when it is a restart time (Yes), the control unit 20 sets the instruction current value to the second current value I2 (S4).

  In step S11, when it is not at the time of restart (No), the control unit 20 determines whether or not the pressure regulating valve R is being driven (S10). In step S10, when the pressure regulating valve R is being driven (Yes), the process proceeds to step S4. In step S10, when the pressure regulating valve R is not being driven (No), the control unit 20 ends this control as it is.

  Next, an example of setting the command current value to the pressure regulating valve R when the engine is restarted from the idling stop state will be described with reference to FIG.

  As shown in FIG. 5 (c), after the driver stops the vehicle CR by stepping on the brake pedal BP, when the idling stop condition is met, the engine automatically stops, as shown in FIG. 5 (a). As described above, the engine speed becomes zero (time t2). Thereafter, when the driver weakens the force of stepping on the brake pedal BP during idling stop, the wheel cylinder pressure (master cylinder pressure) gradually decreases (between times t3 and t4) as shown in FIG. 5 (d). .

  When the wheel cylinder pressure (master cylinder pressure) reaches the predetermined value P1 at time t4, the command current value becomes the second current value I2 (first current value corresponding to the predetermined value P1) as shown in FIG. The pressure regulating valve R is controlled with this indicated current value. As a result, as shown in FIG. 5D, the wheel cylinder pressure is reliably held at the predetermined value P1.

  Thereafter, when the engine is restarted (time t5), the power supply voltage temporarily decreases as shown in FIG. At the time of this restart, as shown in FIG. 5 (e), the command current value remains set at the second current value I2, and therefore, as indicated by the broken line in FIG. Even if the actual current value decreases, it can be suppressed that the current value becomes lower than the first current value I1.

  As a result, as shown in FIG. 5 (d), the wheel cylinder pressure is reliably maintained at the predetermined value P1 even when the power supply voltage is lowered when the engine is restarted. Thereafter, as shown in FIG. 5 (a), when the engine speed reaches a predetermined value N1 (time t7), as shown in FIG. 5 (e), the command current value is changed from the second current value I2 to the first current value. It is switched to I1.

  Thereby, when the engine speed reaches the predetermined value N1, that is, when the power supply voltage is restored to the normal state, the first current value I1 smaller than the second current value I2 is switched. The heat generation and load of the pressure regulating valve R due to continuing control of the pressure regulating valve R can be reduced. Since the power supply voltage is restored to the normal state when switching to the first current value I1 smaller than the second current value I2 as described above, the wheel cylinder pressure is predetermined as shown in FIG. It is reliably held at the value P1.

  Thereafter, as shown in FIG. 5 (a), when the driving force (engine speed) of the engine is stabilized (time t8), the indicated current value is gradually decreased as shown in FIG. 5 (e). Accordingly, as shown in FIG. 5D, the wheel cylinder pressure is gradually reduced.

As described above, in the present embodiment, the following effects can be obtained in addition to the effects described above.
By performing the restart determination based on the engine speed, it can be determined whether the restart has been completed properly. In other words, for example, when the completion of restart is determined based on the voltage value of the power supply voltage, the power supply voltage may fluctuate due to other factors and may be erroneously determined. By performing the above, erroneous determination can be prevented.

[Second Embodiment]
Next, a second embodiment of the present invention will be described in detail with reference to the drawings as appropriate. In addition, since this embodiment changes a part of control part 20 which concerns on above-mentioned 1st Embodiment, about the component similar to 1st Embodiment, the same code | symbol is attached | subjected, and the The description will be omitted.

  As shown in FIG. 6, the control unit 20A according to the second embodiment includes a restart determination unit 21 and a completion state determination unit 22 similar to those in the first embodiment, and is somewhat different from the first embodiment. Different storage 23A and fluid pressure holding means 24A are provided.

  The storage unit 23A stores the first current value I1 and the second current value I2 that are the same as those in the first embodiment, and the second current value I2 that is larger than the first current value I1 and smaller than the second current value I2. Three current values I3 (see FIG. 8E) are further stored. Note that the third current value I3 is such that the actual current value flowing through the pressure regulating valve R does not fall below the first current value I1 when the engine torque rises (when the power supply voltage has not recovered to approximately 100%). Any value may be used, and it is set as appropriate by experiment, simulation, or the like.

  The hydraulic pressure holding means 24A holds the brake hydraulic pressure (wheel cylinder pressure) at the second current value I2 before the engine torque rises after the engine restarts, and the first condition is that the engine torque rises. It is configured to switch from the second current value I2 to the third current value I3 and to switch from the third current value I3 to the first current value I1 on the condition that the restart is completed. Specifically, when the restart signal is input from the restart determination unit 21, the hydraulic pressure holding unit 24A reads the second current value I2 from the storage unit 23A and uses the second current value I2 as the instruction current. The pressure regulating valve R is controlled as a value.

  Further, the hydraulic pressure holding means 24A determines whether or not the engine torque input from the ECU 93 is equal to or greater than a predetermined value T1 (see FIG. 8F) (whether or not it has risen), and is equal to or greater than the predetermined value T1. In the case where the pressure is detected, the third current value I3 is read from the storage unit 23A, and the pressure regulating valve R is controlled using the third current value I3 as an instruction current value.

  Here, the time from when the engine restarts (time t5) until the engine torque rises (between times t5 and t6) and the time until the power supply voltage recovers to some extent (approximately 50%) (between times t5 and t6). Is substantially constant regardless of temperature conditions and the like. Therefore, it is possible to determine whether or not the power supply voltage has recovered to some extent by looking at the rise of the engine torque.

  In the second embodiment, when the power supply voltage recovers to some extent as described above, the instruction current value is switched from the second current value I2 to a third current value I3 smaller than this, so the first embodiment Compared to the above, it is possible to further suppress the heat generation and load of the pressure regulating valve R.

  Further, when the completion signal is input from the completion state determination unit 22, the hydraulic pressure holding unit 24A reads the first current value I1 from the storage unit 23A, and uses the first current value I1 as the instruction current value to adjust the pressure regulating valve R. To control. Note that the control during idling stop of the hydraulic pressure holding unit 24A and the control for gradually decreasing the command current value from the first current value I1 are the same as in the first embodiment.

  Specifically, the control unit 20A according to the second embodiment executes control according to the flowchart shown in FIG. Since the flowchart shown in FIG. 7 is obtained by adding new processes (S21, S22) to the flowchart shown in FIG. 4, the description of the same processes as those in the flowchart of FIG. 4 will be omitted.

  After setting the command current value to the second current value in step S4, the control unit 20 determines whether or not the engine torque is equal to or greater than a predetermined value T1 (S21). In step S21, when the engine torque is less than the predetermined value T1 (No), the control unit 20 controls the pressure regulating valve R with the second current value set in step S4 (S9).

  In step S21, when the engine torque is equal to or greater than the predetermined value T1 (Yes), the control unit 20 determines whether or not the engine speed is equal to or greater than the predetermined value N1 (S5). In step S5, when the engine speed is less than the predetermined value N1 (No), the command current value is switched to the third current value I3 (S22), and the pressure regulating valve R is controlled with the third current value I3. (S9).

  Next, an example of setting the command current value to the pressure regulating valve R when the engine is restarted from the idling stop state will be described with reference to FIG. The example of FIG. 8 shows an example in which the amount of depression of the brake pedal BP by the driver is maintained during idling stop, unlike the example of FIG.

  When the amount of depression of the brake pedal BP by the driver is maintained during idling stop (between times t2 and t5), the wheel cylinder pressure is a value equal to or greater than a predetermined value P1, as shown in FIG. 8 (d). Therefore, as shown in FIG. 8E, the command current value of the pressure regulating valve R becomes zero. When the engine is restarted at time t5, the command current value of the pressure regulating valve R is set to the second current value I2, as shown in FIG. 8 (e).

  As a result, even if the power supply voltage is temporarily lowered when the engine is restarted, the indicated current value becomes the second current value I2, so that the wheel cylinder pressure is reliably set to the predetermined value P1 as in the first embodiment. It can hold above. Thereafter, as shown in FIG. 8 (f), when the engine torque becomes equal to or greater than the predetermined value T1 (time t6), the command current value is switched to the third current value I3, so that the heat generation of the pressure regulating valve R can be suppressed. .

  Further, since the command current value is not lowered to the first current value I1 at time t6, even if the recovery of the power supply voltage is delayed and the actual current value becomes smaller than the command current value, the first current value The third current value I3 larger than I1 can prevent the actual current value from falling below the first current value I1.

  Thereafter, as in the first embodiment, as shown in FIG. 8A, when the engine speed becomes equal to or higher than a predetermined value N1 (time t7), as shown in FIG. The command current value is switched to the first current value I1.

The present invention is not limited to the above embodiments, and can be used in various forms as exemplified below.
In each of the above embodiments, it is determined that the restart of the engine has been completed on the condition that the engine speed has reached or exceeded the predetermined value N1, but the present invention is not limited to this. For example, it may be determined that the engine restart has been completed on the condition that the voltage value of the power supply voltage is equal to or greater than a predetermined value, or that a predetermined time has elapsed since the engine was restarted. It may be determined that the restart of the engine is completed as a condition.

  In each of the above-described embodiments, the current value supplied to the pressure regulating valve R is exemplified as the control amount. However, the present invention is not limited to this. For example, when the brake fluid pressure is held by the electric booster during idling stop. The current value supplied to the electric booster may be used.

DESCRIPTION OF SYMBOLS 20 Control part 21 Restart determination means 22 Completion state determination means 23 Storage part 24 Hydraulic pressure holding means 91 Wheel speed sensor 92 Brake pedal sensor 93 ECU
100 Brake fluid pressure control device for vehicle FL, FR, RL, RR Wheel brake I1 First current value I2 Second current value R Pressure regulating valve

Claims (4)

A brake fluid pressure control device for a vehicle capable of holding a brake fluid pressure while the engine is stopped,
Restart determination means for determining whether or not the engine has been restarted;
Completion state determination means for determining whether or not restart of the engine is completed;
A storage unit that stores a first control amount corresponding to a brake fluid pressure necessary for maintaining the stop state of the vehicle, and a second control amount larger than the first control amount;
Maintaining the brake fluid pressure at the second control amount on condition that the engine has been restarted and maintaining the brake fluid pressure at the first control amount on condition that restart has been completed And a brake fluid pressure control device for a vehicle.   The vehicular brake hydraulic pressure control apparatus according to claim 1, wherein the completion state determination unit determines that the restart is completed on the condition that the engine speed has reached a predetermined value or more. The storage unit stores a third control amount that is larger than the first control amount and smaller than the second control amount,
The hydraulic pressure holding means holds the brake hydraulic pressure by the second control amount before the engine torque rises after the engine restarts, and the second control is performed on the condition that the engine torque has risen. The vehicular brake hydraulic pressure control device according to claim 1, wherein the vehicular brake hydraulic pressure control device is switched from the third control amount to the first control amount on condition that the restart is completed. .   The vehicular brake according to any one of claims 1 to 3, wherein the control amount is a current value supplied to a proportional solenoid valve capable of adjusting a brake fluid pressure in a wheel brake. Hydraulic control device.

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