JP4730100B2 - Brake control device - Google Patents

Description

  The present invention relates to a brake control device that controls braking force applied to wheels provided in a vehicle.

  2. Description of the Related Art Conventionally, a vehicle fluid that applies a braking force to a vehicle wheel by generating a hydraulic pressure in the hydraulic circuit according to the operating force of a brake pedal and supplying the hydraulic pressure in the hydraulic circuit to a wheel cylinder. Pressure brake devices are known.

  In such a hydraulic brake device for a vehicle, if air is mixed in the hydraulic circuit for some reason, the driver feels uncomfortable with the operation of the brake pedal, or until the braking is started after the brake operation is performed. The time lag may increase.

In order to detect such air contamination, Patent Document 1 relates to the rise of the output hydraulic pressure detected by the output hydraulic pressure detection unit with respect to the start of the rise of the brake operation amount detected by the brake operation amount detection unit. There is disclosed a hydraulic brake device for a vehicle that includes an air mixing detection unit that detects air mixing into a hydraulic circuit based on a response time.
Japanese Patent Laid-Open No. 2003-127849

  However, the response time from the brake operation to the rise of the output hydraulic pressure is not only due to air mixing, but also due to abnormalities in hardware such as pumps and valves that constitute the brake device, and abnormalities in the control unit that controls the brake device. May fluctuate. Therefore, in the hydraulic brake device for a vehicle described in Patent Document 1, it is difficult to distinguish between a case where the response delay is increased due to air mixing and a case where the response delay is increased due to an abnormality in hardware or the control unit. . In addition, the air mixing amount cannot be estimated.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a brake control device capable of accurately determining air contamination.

In order to solve the above-described problems, a brake control device according to an aspect of the present invention is a brake control device that controls a braking force applied to a wheel provided in a vehicle. A valve for adjusting the pressure of the working fluid acting on the wheel cylinder, a pressure detecting means for detecting the pressure of the working fluid supplied to the wheel cylinder, Based on the pressure fluctuation of the working fluid detected by the pressure detection means, it is determined that air is mixed in the working fluid, and the air mixing determination unit determines that air is mixed in. In this case, an air mixing amount calculation unit that calculates a mixing amount of air mixed in the working fluid based on the pressure fluctuation of the working fluid detected by the pressure detection unit.

  According to this aspect, the air mixing determination unit that determines whether or not air is mixed in the working fluid and the air mixing amount calculation unit that calculates the mixing amount of air mixed in the working fluid are provided. The state of the fluid can be determined by a plurality of means. Therefore, it is possible to determine air contamination with higher accuracy than in the case where the information indicating the state of the working fluid is one, and appropriate brake control can be performed. In addition, since not only the presence / absence of air mixing but also the amount of air mixing can be calculated, the state of the working fluid mixed with air can be determined with high accuracy. In addition, the number of vehicle inspections and maintenance due to erroneous detection can be suppressed.

  The air mixing determination unit may determine whether air is mixed in the working fluid based on an amplitude of a pressure fluctuation at the time of pressurization of the working fluid after a braking request. For example, when a linear valve is opened at the time of brake control, if air is mixed in the flow path to the wheel cylinder, the rigidity of the hydraulic circuit is lowered. Therefore, in order to increase the predetermined reference pressure to the predetermined target pressure, the control does not increase the pressure for the supplied working fluid in the control under the assumption that the working fluid should be sent at a predetermined ratio. In such a situation, when the valve control unit 201 further increases the opening of the valve in order to send the working fluid, the working fluid suddenly flows into the low pressure part and the air collapses, so that the pressure suddenly increases and the target pressure is reduced. May pulsate beyond. These vibrations are detected as pulsations of the working fluid. Therefore, it is possible to determine whether air is mixed in the working fluid based on the amplitude of pressure fluctuation at the time of pressure increase after a braking request by normal brake control. Here, the braking request is generated when a braking force should be applied to the vehicle. The braking request is, for example, when the driver operates the brake operation member, or when the distance to the other vehicle is reduced from a predetermined distance when the distance to the other vehicle is automatically controlled during traveling. It is born.

  According to this, for example, even when the response delay due to air mixing is apparently reduced by vibration and does not change much from the normal state, it is possible to accurately determine air mixing. In addition, since vibration due to air mixing is likely to occur at the initial stage of pressure increase, the amplitude within a predetermined time after the braking request may be detected. In this way, it is possible to determine air contamination earlier.

  The air mixing determination unit is configured to detect air based on a comparison between the detected pressure of the working fluid and a reference pressure that is a reference for air mixing determination when the working fluid acting on the wheel cylinder after the braking request is finished. It may be determined whether or not it is mixed in the working fluid. For example, when the linear valve is opened after releasing the brake control, if air is mixed in the flow path to the wheel cylinder, it takes extra time to lower the pressure from the state where the working fluid is pressurized. Therefore, it is possible to determine whether or not air is mixed in the working fluid based on a comparison between the reference pressure that serves as a reference during pressure reduction and the detected pressure of the working fluid in a state after the release of the normal brake control.

  The air mixing determination unit may determine that air is mixed in the working fluid when a response delay of the pressure of the working fluid with respect to the reference pressure is greater than a predetermined threshold. According to this, it is possible to accurately determine air contamination even after the braking request is completed.

  The air mixing amount calculation unit is configured to perform air based on a time during which a response delay of the pressure of the working fluid with respect to a target pressure calculated according to a required braking force exceeds a predetermined reference deviation, and a gradient of the target pressure. The mixing amount may be calculated. Even if air is mixed in the working fluid, the response delay varies depending on the mixing amount. In addition, even if the air mixing amount is the same, the response delay varies depending on the gradient of the target pressure calculated according to the required braking force. Therefore, referring to a map in which the correlation with the air mixing amount is determined in advance based on the time when the response delay of the pressure of the working fluid exceeds a predetermined reference deviation and the gradient of the target pressure, air mixing is performed. By calculating the amount, it is possible to determine the amount of mixed air with higher accuracy.

  Further, the air mixing amount calculation unit determines the amount of air mixing when the air mixing determination unit determines that air is mixed, so that the hardware such as pumps and valves constituting the brake device A response delay caused by an abnormality or an abnormality of a control unit that controls the brake device and a response delay due to air mixing can be determined, and air mixing can be accurately determined.

  The predetermined reference deviation may be set according to the temperature of the working fluid. The viscosity of brake oil or the like used as a working fluid changes with temperature. In general, the viscosity increases at low temperatures and decreases at high temperatures. Therefore, the speed of passing through the orifice of a valve such as a linear valve varies depending on the temperature, and the response delay varies depending on the temperature. Therefore, by setting a predetermined reference deviation to be compared with the response delay of the pressure of the working fluid with respect to the target pressure according to the temperature of the working fluid, it is possible to accurately calculate the amount of air mixed even if the temperature changes. it can.

  You may further provide the valve control part which controls the opening degree of the said valve. When the air mixing determination unit determines that the air is mixed in the working fluid, the valve control unit determines whether the valve has been operated for a predetermined time after a braking request based on the valve opening set when there is no air mixing. You may control the said valve | bulb so that an opening degree may become large. When air is mixed, the response delay in a predetermined time after the braking request becomes particularly large. Therefore, the response delay of the predetermined time after the braking request is improved by controlling the valve so that the valve opening becomes larger for the predetermined time after the braking request than the valve opening set when there is no air mixing. can do.

  Based on the air mixing amount calculated by the air mixing amount calculation unit, the valve control unit increases the valve opening for a predetermined time after a braking request than the valve opening set when there is no air mixing. You may control the said valve so that it may become. When air is mixed, the response delay in a predetermined time after the braking request becomes particularly large. In addition, the response delay increases as the air mixing amount increases. Therefore, by controlling the valve so that the opening of the valve becomes larger based on the air mixing amount for a predetermined time after the braking request than the opening of the valve set when there is no air mixing, the predetermined opening after the braking request is made. The response delay of time can be improved.

  When the air mixing determination unit determines that air is mixed in the working fluid, the valve control unit acts on the wheel cylinder to the extent that no braking force is generated when no brake operation is performed. The valve may be controlled to maintain the pressure of the working fluid at a predetermined pressure. When air is mixed, the response delay in a predetermined time after the braking request becomes particularly large. Therefore, in a state where the brake operation is not performed, a response for a predetermined time after the braking request is made by controlling the valve so as to maintain a predetermined pressure higher than the pressure of the normal working fluid so that the braking force is not generated. Delay can be improved.

  The valve control unit is configured so that the pressure of the working fluid that acts on the wheel cylinder to the extent that no braking force is generated based on the air mixing amount calculated by the air mixing amount calculation unit when the brake operation is not performed. The valve may be controlled to maintain a predetermined pressure. When air is mixed, the response delay in a predetermined time after the braking request becomes particularly large. In addition, the response delay increases as the air mixing amount increases. Therefore, by controlling the valve so as to maintain a predetermined pressure that is set larger based on the air mixing amount than the pressure of the normal working fluid so that the braking force is not generated in a state where the brake operation is not performed. The response delay of a predetermined time after the braking request can be improved.

  According to the present invention, it is possible to accurately determine air contamination.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

(Schematic configuration of brake control device)
FIG. 1 is a system diagram showing a brake control device 10 according to the embodiment. A brake control device 10 shown in FIG. 1 constitutes an electronically controlled brake system (ECB) for a vehicle, and brakes for four wheels of the vehicle in response to an operation of a brake pedal 12 as a brake operation member by a driver. Are set independently and optimally. That is, the brake control device 10 can control the braking force applied to the wheels provided on the vehicle.

  The brake pedal 12 is connected to a master cylinder 14 that sends out brake oil as working fluid (working fluid) in response to a depression operation by the driver. The brake pedal 12 is provided with a stroke sensor 46 for detecting the depression stroke.

  Further, a reservoir tank 26 is connected to the master cylinder 14, and a reaction force corresponding to the operating force of the brake pedal 12 by the driver is applied to one output port of the master cylinder 14 via the on-off valve 23. A stroke simulator 24 to be created is connected. The on-off valve 23 is a normally closed solenoid valve that is closed when not energized and is switched to an open state when an operation of the brake pedal 12 by the driver is detected.

  A brake hydraulic pressure control pipe 16 for the right front wheel is connected to one output port of the master cylinder 14. The brake hydraulic control pipe 16 is connected to a wheel cylinder 20FR for the right front wheel that applies a braking force to the right front wheel (not shown). A brake hydraulic pressure control pipe 18 for the left front wheel is connected to the other output port of the master cylinder 14, and the brake hydraulic pressure control pipe 18 is for the left front wheel that applies a braking force to the left front wheel (not shown). Connected to the wheel cylinder 20FL.

  A right electromagnetic on-off valve 22FR is provided in the middle of the brake hydraulic control pipe 16 for the right front wheel, and a left electromagnetic on-off valve 22FL is provided in the middle of the brake hydraulic control pipe 18 for the left front wheel. The right electromagnetic on-off valve 22FR and the left electromagnetic on-off valve 22FL are both open when not energized, and are normally open when the operation of the brake pedal 12 by the driver is detected. It is.

  A right master pressure sensor 48FR for detecting the master cylinder pressure on the right front wheel side is provided in the middle of the brake hydraulic control pipe 16 for the right front wheel. A left master pressure sensor 48FL for measuring the master cylinder pressure on the left front wheel side is provided.

  In the brake control apparatus 10, when the brake pedal 12 is depressed by the driver, the stroke operation amount is detected by the stroke sensor 46. The master detected by the right master pressure sensor 48FR and the left master pressure sensor 48FL is detected. The depressing operation force (depressing force) of the brake pedal 12 can also be obtained from the cylinder pressure. As described above, it is preferable from the viewpoint of fail-safe that the master cylinder pressure is monitored by the two of the right master pressure sensor 48FR and the left master pressure sensor 48FL assuming the failure of the stroke sensor 46.

  On the other hand, one end of a hydraulic supply / discharge pipe 28 is connected to the reservoir tank 26, and a suction port of an oil pump 34 driven by a motor 32 is connected to the other end of the hydraulic supply / discharge pipe 28. . The discharge port of the oil pump 34 is connected to a high pressure pipe 30, and an accumulator 50 and a relief valve 53 are connected to the high pressure pipe 30. In the present embodiment, a reciprocating pump including two or more pistons (not shown) that are reciprocally moved by the motor 32 is employed as the oil pump 34. Further, as the accumulator 50, an accumulator 50 that converts the pressure energy of the brake oil into the pressure energy of an enclosed gas such as nitrogen is stored.

  The accumulator 50 stores brake oil whose pressure has been increased to about 14 to 22 MPa by the oil pump 34, for example. Further, the valve outlet of the relief valve 53 is connected to the hydraulic supply / discharge pipe 28. When the pressure of the brake oil in the accumulator 50 increases abnormally to about 25 MPa, for example, the relief valve 53 is opened and the high-pressure brake is opened. The oil is returned to the hydraulic supply / discharge pipe 28.

  Further, the high-pressure pipe 30 is provided with an accumulator pressure sensor 51 that detects the outlet pressure of the accumulator 50, that is, the pressure of the brake oil in the accumulator 50.

  The high pressure pipe 30 is connected to the right front wheel wheel cylinder 20FR, the left front wheel wheel cylinder 20FL, the right rear wheel wheel cylinder 20RR, and the left rear wheel through the pressure increasing valves 40FR, 40FL, 40RR, 40RL. It is connected to the cylinder 20RL. Hereinafter, the wheel cylinders 20FR to 20RL will be collectively referred to as “wheel cylinders 20”, and the pressure increase valves 40FR to 40RL will be appropriately collectively referred to as “pressure increase valves 40”. Each of the pressure increasing valves 40 is a normally closed electromagnetic flow control valve (linear valve) that is closed when not energized and is used to increase the pressure of the wheel cylinder 20 as necessary.

  A disc brake unit is provided for each wheel of the vehicle (not shown), and each disc brake unit generates a braking force by pressing the brake pad against the disc by the action of the wheel cylinder 20.

  Further, the wheel cylinder 20FR for the right front wheel and the wheel cylinder 20FL for the left front wheel are connected to the hydraulic supply / discharge pipe 28 via the pressure reducing valve 42FR or 42FL, respectively. The pressure reducing valves 42FR and 42FL are normally closed electromagnetic flow control valves (linear valves) used for pressure reduction of the wheel cylinders 20FR and 20FL as necessary. On the other hand, the wheel cylinder 20RR for the right rear wheel and the wheel cylinder 20RL for the left rear wheel are connected to the hydraulic supply / discharge pipe 28 via a pressure reducing valve 42RR or 42RL which is a normally open electromagnetic flow control valve. . Hereinafter, the pressure reducing valves 42FR to 42RL are collectively referred to as “pressure reducing valve 42” as appropriate.

  FIG. 2 is a cross-sectional view schematically showing a cross section of a normally closed linear valve. As shown in FIG. 2, the pressure increasing valve 40 and the pressure reducing valves 42 FR and 42 FL, which are normally closed linear valves, include a valve seat 130, a valve element 132, a spring 136, a solenoid 139, and a movable member 134. The fixing member 135 is included. The valve element 132 is provided so as to be able to approach and separate from the valve seat 130, and the spring 136 biases the valve element 132 in the direction in which the valve element 132 approaches and seats on the valve seat 130. When a current is supplied, the solenoid 139 applies an electromagnetic driving force in a direction in which the movable member 134 approaches the fixed member 135, that is, in a direction in which the valve element 132 is separated from the valve seat 130. In a state where no current is supplied to the solenoid 139, the valve element 132 is seated on the valve seat 130 by the biasing force of the spring 136, and the linear valve is closed.

  Furthermore, a differential pressure acting force according to the differential pressure across the front and rear acts in a direction to separate the valve element 132 from the valve seat 130. Since the pressure increasing valve 40 is provided between the accumulator 50 and the wheel cylinder 20, the differential pressure between the front and rear corresponds to the differential pressure between the accumulator 50 and the wheel cylinder 20. The pressure reducing valves 42FR and 42FL are provided between the wheel cylinders 20FR and 20FL and the reservoir tank 26. Since the hydraulic pressure of the reservoir tank 26 is atmospheric pressure, the differential pressure before and after corresponds to the hydraulic pressure of the wheel cylinders 20FR and 20FL. To do.

  The pressure increasing valve 40 and the pressure reducing valves 42FR and 42FL are subjected to a biasing force by the spring 136, an electromagnetic driving force by the solenoid 139, and a differential pressure acting force according to the differential pressure before and after. Therefore, the relative position of the valve element 132 with respect to the valve seat 130 is determined based on the relationship between these forces. Therefore, the valve element 132 is driven by supplying a current to the solenoid 139 and controlling the electromagnetic driving force, and the hydraulic pressure acting on the wheel cylinder 20 can be controlled by opening the linear valve.

  FIG. 3 is a cross-sectional view schematically showing a cross section of a normally open linear valve. As shown in FIG. 3, the pressure reducing valves 42RR and 42RL, which are normally open linear valves, include a valve seat 140, a valve element 142, a spring 146, a solenoid 149, a movable member 144, and a fixed member 145. It is comprised including. The valve element 142 is provided so as to be separated and accessible from the valve seat 140, and the spring 146 urges the valve element 142 in a direction to separate the valve element 142 from the valve seat 140. When the current is supplied, the solenoid 149 applies an electromagnetic driving force in a direction in which the movable member 144 approaches the fixed member 145, that is, in a direction in which the valve element 142 approaches the valve seat 140. In a state where no current is supplied to the solenoid 149, the valve element 142 is separated from the valve seat 140 by the biasing force of the spring 146, and the linear valve is opened.

  Furthermore, since the pressure reducing valves 42RR and 42RL are provided between the wheel cylinders 20RR and 20RL and the reservoir tank 26, a differential pressure acting force according to the hydraulic pressure of the wheel cylinders 20RR and 20RL acts. Therefore, the relative position of the valve element 142 with respect to the valve seat 140 is determined by the relationship between the biasing force of the spring 146, the electromagnetic driving force by the solenoid 149, and the differential pressure acting force according to the wheel cylinder pressure. Therefore, the valve element 142 is driven by supplying a current to the solenoid 149 and controlling the electromagnetic driving force, and the hydraulic pressure acting on the wheel cylinder 20 can be maintained by closing the linear valve.

  Further, as shown in FIG. 1, the brake control device 10 according to the present embodiment has wheels corresponding to the wheel cylinders 20FR to 20RL for the right front wheel, the left front wheel, the right rear wheel, and the left rear wheel, respectively. Cylinder pressure sensors 44FR, 44FL, 44RR and 44RL for detecting wheel cylinder pressure, which is the pressure of brake oil acting on the cylinder 20, are provided. Hereinafter, the cylinder pressure sensors 44FR to 44RL are collectively referred to as “cylinder pressure sensor 44” as appropriate. The cylinder pressure sensor 44 functions as pressure detection means for detecting the pressure of brake oil as a working fluid that acts on the wheel cylinder 20.

  The right electromagnetic on-off valve 22FR and the left electromagnetic on-off valve 22FL, the pressure increasing valves 40FR to 40RL, the pressure reducing valves 42FR to 42RL, the oil pump 34, the accumulator 50, and the like constitute the hydraulic actuator 80 of the brake control device 10. The hydraulic actuator 80 is controlled by an electronic control unit (hereinafter referred to as “ECU”) 200. The ECU 200 includes a CPU that executes various arithmetic processes, a ROM that stores various control programs, a RAM that is used as a work area for data storage and program execution, an input / output interface, a memory, and the like.

(Control block diagram for determining air contamination)
FIG. 4 is a control block diagram of the brake control device 10 according to the first embodiment. As shown in FIG. 4, the ECU 200 is electrically connected to the above-described right electromagnetic on-off valve 22FR, left electromagnetic on-off valve 22FL, on-off valve 23, pressure increasing valves 40FR to 40RL, pressure reducing valves 42FR to 42RL, and the like. . The right electromagnetic on-off valve 22FR, the left electromagnetic on-off valve 22FL, the on-off valve 23, the pressure increasing valves 40FR to 40RL, and the pressure reducing valves 42FR to 42RL are controlled by a valve control unit 201 constructed in the ECU 200, respectively.

  The ECU 200 is given a signal indicating the wheel cylinder pressure in the wheel cylinders 20FR to 20RL from the cylinder pressure sensors 44FR to 44RL, and a signal indicating the rotational speed of the wheels from the wheel speed sensor 60. Further, the ECU 200 is given a signal indicating the depression stroke of the brake pedal 12 from the stroke sensor 46, and is given a signal indicating the master cylinder pressure from the right master pressure sensor 48FR and the left master pressure sensor 48FL.

  In the brake control device 10 configured as described above, the ECU 200 calculates the braking force applied to each wheel in the following manner. The required braking force calculation unit 203 constructed in the ECU 200 calculates a target deceleration of the vehicle from the depression stroke of the brake pedal 12 and the master cylinder pressure, and the required braking force required to achieve the target deceleration. Is calculated. Next, the pressure setting unit 202 built in the ECU 200 calculates the total working fluid pressure according to the required braking force. Here, the total working fluid pressure corresponds to the sum of the front wheel side wheel cylinder pressure acting on the front wheel wheel cylinders 20FR and 20FL and the rear wheel side wheel cylinder pressure acting on the rear wheel wheel cylinders 20RR and 20RL. Is.

  The distribution of the front wheel side wheel cylinder pressure and the rear wheel side wheel cylinder pressure with respect to the total working fluid pressure is determined in advance and stored in the ECU 200. Both the front wheel side wheel cylinder pressure and the rear wheel side wheel cylinder pressure are increased in proportion to the pedaling force when the pedaling force of the brake pedal 12 by the driver is relatively small, and the wheel cylinder pressure reaches a predetermined upper limit value. The upper limit is maintained regardless of the magnitude of the pedal effort. The pedaling force is obtained from the master cylinder pressure measured by the right master pressure sensor 48FR and the left master pressure sensor 48FL, for example.

  In this embodiment, the front wheel side wheel cylinder pressure is set to 10.8 MPa, for example. In this embodiment, the rear wheel side wheel cylinder pressure is set to 5.0 MPa, for example. The reason why the upper limit value on the rear wheel side is set lower than the upper limit value on the front wheel side in this way is the continuous energization during braking of the rear wheel side pressure reducing valves 42RR and 42RL which are normally open solenoid valves. This is to suppress the heat generation due to.

  Based on such distribution, the pressure setting unit 202 sets a target pressure for each wheel cylinder. Then, the control current value to the pressure increasing valve 40 and the pressure reducing valve 42 is determined by the valve control unit 201 so that each wheel cylinder pressure becomes the target pressure, and the pressure increasing valve 40 and the pressure reducing valve 42 are opened and closed.

  While the amount of operation of the brake pedal 12 increases and the required braking force increases, the pressure increasing valve 40 is opened and the pressure reducing valve 42 is closed. As a result, the brake oil stored in the accumulator 50 is supplied to the wheel cylinder 20 through the booster valve 40 that is opened. At this time, since the pressure reducing valve 42 is in the closed state, the wheel cylinder pressure increases toward the target pressure corresponding to the required braking force. On the contrary, while the required braking force is decreasing, the pressure reducing valve 42 is opened, and the brake oil in the wheel cylinder 20 is returned to the reservoir tank 26.

  In the ECU 200 of the brake control device 10 according to the present embodiment, a pressure fluctuation calculation unit 204 is further constructed. As will be described later, the pressure fluctuation calculation unit 204 operates air based on a plurality of pieces of information indicating the state of the working fluid calculated by a plurality of different calculations using the pressure fluctuation of the working fluid detected by the cylinder pressure sensor 44. Determine the state of being mixed in the fluid.

  The pressure fluctuation calculation unit 204 according to the present embodiment calculates the pulsation of the working fluid pressure at the time of pressure increase and the response delay with respect to the target pressure by different calculations using the detected pressure fluctuation of the working fluid. Then, it is determined whether or not air is mixed in the working fluid based on the calculated pulsation of the working fluid pressure, which is information indicating the state of the working fluid, and the response delay. Hereinafter, a method for calculating a response delay with respect to a target pressure and a pulsation of the working fluid pressure during pressure increase, and a method for determining whether air is mixed in the working fluid using the information will be described.

(Pressure fluctuation during pressurization)
The above-described pressure increasing valve 40 is connected to a wheel cylinder 20 that is supplied with a working fluid and applies a braking force to the wheel via a flow path, and adjusts the pressure of the working fluid that acts on the wheel cylinder 20. That is, the pressure increasing valve 40 is opened based on the required braking force of the brake control calculated by the braking request by the brake operation by the driver, and increases the pressure of the working fluid.

  FIG. 5 is a diagram illustrating pressure fluctuations of the working fluid at the time of a braking request according to the first embodiment. The vertical axis indicates the pressure of the working fluid, and the horizontal axis indicates the time from the occurrence of the braking request.

  A line P1 shown in FIG. 5 is a target pressure (also referred to as a hydraulic finger pressure value) set by the pressure setting unit 202 based on the required braking force calculated by the required braking force calculation unit. The line P1 according to the present embodiment is set so that the pressure rises with a constant pressure gradient with reference to the time when braking is requested, and becomes constant with a preset upper limit value. On the other hand, a line P2 shown in FIG. 5 schematically shows pressure fluctuations when the cylinder pressure sensor 44 detects the working fluid pressure at the time of pressurization in a state where air is not mixed in the working fluid.

  As shown in FIG. 5, when the pressure of the working fluid actually controlled rises from the braking request and rises, the line P2 has a slight response delay with respect to the line P1 indicating the target pressure. One reason for this is that the control of the braking force is usually designed with an emphasis on stability and has some play. Another reason is, for example, the influence of elasticity such as a wheel cylinder or piping connected to the wheel cylinder. That is, even if the working fluid is normally supplied to the wheel cylinder in response to a braking request, the wheel cylinder and piping are first elastically expanded, and the contribution to the increase in the wheel cylinder pressure is small at first. .

  At the same time, since the target pressure increases with time immediately after the braking request, the working fluid pressure to be controlled tends to deviate from the target pressure even in a normal case without air mixing. As described above, the response delay of the increase in the detected working fluid pressure with respect to the increase in the target pressure usually occurs slightly. In addition, when air is mixed in the working fluid, control is performed on the premise that no air is contained, particularly in a brake control device equipped with a linear valve, so that a predetermined reference pressure is changed to a predetermined target pressure. In other words, the control is performed under the assumption that the working fluid should be sent at a predetermined rate. As a result, when air is mixed in, the working fluid must be sent in excess of the air, but if the predetermined ratio is set, an extra time is required for the air, which leads to a time delay.

Therefore, in this embodiment, in order to determine whether or not air is mixed in the working fluid, the pressure fluctuation calculation unit 204 calculates a response delay with respect to the target pressure fluctuation set by the pressure setting unit 202 and calculates a threshold value. Compare with For example, when the response delay d ₁ exceeds a predetermined threshold value 300 ms as indicated by a line P 3 shown in FIG. 5, it is determined that air is mixed in the working fluid of the control system of the brake control device 10.

  As described above, the pressure fluctuation calculation unit 204 is air mixed in the working fluid based on the response delay which is one of the information indicating the state of the working fluid calculated by the calculation using the pressure fluctuation of the working fluid. It can be determined whether or not.

  The pressure fluctuation calculation unit 204 according to the present embodiment further calculates other information indicating the state of the working fluid by a calculation different from the calculation that calculates the response delay using the pressure fluctuation of the working fluid, and takes the response delay into account. Thus, it can be determined whether or not air is mixed in the working fluid. The response delay of the working fluid pressure may fluctuate not only due to air mixing but also due to abnormalities in hardware such as pumps and valves constituting the brake device, and abnormalities in the control unit that controls the brake device. For this reason, there is a case where air contamination cannot be accurately detected only by response delay information.

  Therefore, the pressure fluctuation calculation unit 204 according to the present embodiment also uses air as the working fluid based on the result of comparing the amplitude due to the pulsation of the pressure fluctuation calculated by calculation using the pressure fluctuation of the working fluid and a predetermined threshold value. Whether it is mixed or not can be determined. This is because the rigidity of the hydraulic circuit is low due to the air mixture, so in order to increase the predetermined reference pressure to the predetermined target pressure, it is necessary to send the working fluid at a predetermined ratio. The pressure does not increase for the working fluid to be sent. In such a situation, when the valve control unit 201 further increases the opening of the valve in order to send the working fluid, the working fluid suddenly flows into the low pressure part and the air collapses, so that the pressure suddenly increases and the target pressure is reduced. May pulsate beyond.

  FIG. 6 is a diagram schematically showing pressure fluctuations detected by the pressure detection means in a state where air mixed in the working fluid is crushed and pulsation is generated. A line P4 shown in FIG. 6 is a pressure fluctuation when the cylinder pressure sensor 44 detects a state in which the air mixed in the working fluid is crushed by the working fluid pressure at the time of pressure increase after the braking request.

When the air collapses and pulsates in this way, the response delay is apparently reduced. For this reason, there is a case where it is not possible to detect even if air is mixed in the information of only the response delay. Therefore, the pressure fluctuation calculation unit 204 according to the present embodiment calculates the amplitude A ₁ from the pressure fluctuation of the working fluid detected by the cylinder pressure sensor 44. Then, the pressure fluctuation calculating unit 204, the amplitude A ₁ calculated functions as a determining air intrusion determination unit air when greater than a predetermined threshold value A ₀ mixed in the working fluid.

  FIG. 7 is a flowchart for explaining an air mixing determination process according to the first embodiment. The process shown in FIG. 7 is performed based on the pressure fluctuation of the working fluid within a predetermined period from the generation of the braking request. Note that the air mixing determination processing can be performed as long as pressure detection means is appropriately provided for any combination of each wheel, each front wheel, each rear wheel, and all the wheels.

  As shown in FIG. 7, when a braking request is generated and the processing of this embodiment is started, the ECU 200 sets the target pressure of each wheel cylinder 20 in the pressure setting unit 202 (S10). Next, the ECU 200 controls the pressure increasing valve 40 and, if necessary, the pressure reducing valve 42 by the valve control unit 201 based on the target pressure, so that the working fluid pressure in each wheel cylinder becomes the target pressure. A working fluid such as brake fluid delivered by the oil pump 34 is supplied to each wheel cylinder 20 (S12). At that time, a signal from the cylinder pressure sensor 44 indicating the measured value of the working fluid pressure acting on the wheel cylinder 20 is received (S14).

Pressure fluctuation calculating section 204 calculates the response delay _{d 1} of the pressure variation of the detected hydraulic fluid pressure to the target pressure (S16), and compares it with a predetermined threshold value _{d 0} (S18). When the response delay d ₁ > d ₀ (Yes in S18), it is determined that air is mixed into the working fluid (S20). On the other hand, when the response delay d ₁ ≦ d ₀ (No in S18), the pressure fluctuation calculating unit 204 further calculates the amplitude A ₁ of the working fluid pressure (S22) and compares it with a predetermined threshold A ₀ (S24). . When the amplitude A ₁ > A ₀ (Yes in S24), it is determined that air is mixed into the working fluid (S20). On the other hand, when the amplitude A ₁ ≦ A ₀ (No in S24), it is determined that there is no air mixture in the working fluid at this time (S26).

  When it is determined that there is no air mixing in either S18 or S24, the air mixing determination processing in the present embodiment is completed, and is similarly performed again when the next execution timing is reached. On the other hand, when it is determined that air is mixed into the working fluid (S20), the passenger can be warned by transmitting the result to the notification unit 205 shown in FIG. 4 (S28). The result may be transmitted together with the warning or instead of the warning to the pressure setting unit 202 or the valve control unit 201 for setting the control condition in the brake control.

  As described above, the brake control device 10 according to the present embodiment uses a plurality of pieces of information indicating the state of the working fluid to determine whether the air is mixed. Air contamination can be determined well, and appropriate brake control and occupant warning can be performed.

(Second Embodiment)
In the first embodiment, as a plurality of pieces of information indicating the state of the working fluid calculated by a plurality of different calculations using the pressure fluctuation of the working fluid, air is operated based on the response delay at the time of pressurization and the amplitude of the pressure fluctuation. It is determined whether or not the fluid is mixed. In the second embodiment, instead of or in addition to the response delay at the time of pressure increase and the amplitude of the pressure fluctuation, the difficulty of pressure release at the time of pressure reduction (hereinafter referred to as the response delay at the time of pressure reduction) is defined as the state of the working fluid. The point used as the information to be shown is a point greatly different from the first embodiment. Hereinafter, description overlapping with that of the first embodiment will be omitted as appropriate, and the description will focus on the main differences with reference to FIGS. 1, 7, and 8.

  Normally, in the electronically controlled brake control device 10 shown in FIG. 1, when the brake operation is released when the vehicle is stopped, the pressure reducing valve 42 is used to reduce the working fluid pressure acting on the wheel cylinder 20 that has been increased. It opens widely and the pressure is reduced rapidly.

(Pressure fluctuation during pressure reduction)
FIG. 8 is a diagram illustrating pressure fluctuations of the working fluid at the end of the braking request according to the second embodiment. The vertical axis indicates the pressure of the working fluid, and the horizontal axis indicates the time from the end of the braking request.

  A line P5 shown in FIG. 8 is a target pressure (also referred to as a hydraulic finger pressure value) set by the pressure setting unit 202 when the working fluid pressure that has been increased after the end of the braking request is decreased. The target pressure in this embodiment can be used as a reference pressure that serves as a reference for air mixing determination. The line P5 according to the present embodiment drops to a predetermined pressure with a constant pressure gradient based on the time when the braking request is completed. On the other hand, a line P6 shown in FIG. 8 schematically shows pressure fluctuation when the cylinder pressure sensor 44 detects the working fluid pressure during pressure reduction in a state where air is not mixed in the working fluid.

As shown in FIG. 8, when air is not mixed in the working fluid, the value is not large although there is a slight response delay. However, when air is mixed in the working fluid, as shown by the line P7, it is difficult for the pressure to decrease particularly in the low pressure portion during pressure reduction. This is thought to be because it takes time for the crushed air to return to its original state. Therefore, in this embodiment, paying attention to the response delay in the low-pressure part, whether or not air is mixed in the working fluid based on a comparison between the detected pressure of the working fluid and a target pressure that is a reference for air mixing determination. Determine. Specifically, it is possible to response delay d ₂ of the pressure of the working fluid relative to the reference pressure is determined that air is larger than a predetermined threshold value are mixed in the working fluid.

  Therefore, instead of or in addition to the process of step S18 or step S24 of the air mixing determination process shown in FIG. 7 described in the first embodiment, the response delay at the time of step-down in this embodiment is determined as the working fluid. By using this as information indicating the state of the air, it is possible to determine the state in which air is mixed in the working fluid using a plurality of pieces of information indicating the state of the working fluid. Therefore, the brake control device according to the present embodiment determines the state in which air is mixed more accurately than the case where the information indicating the state of the working fluid is the same as in the case of the brake control device 10 illustrated in FIG. It is possible to perform appropriate brake control and warning to the occupant.

(Third embodiment)
Next, with reference to FIG. 9 to FIG. 11, a description will be given of a brake control device capable of calculating the presence or absence of air mixing and the amount of air mixing when air is mixed. FIG. 9 is a control block diagram of the brake control device according to the third embodiment. FIG. 10 is a graph showing the relationship between the response delay duration and the target pressure gradient when air is mixed. FIG. 11 is a flowchart for explaining the air mixing determination and the air mixing amount calculation processing according to the third embodiment. Since the outline of the brake control device is substantially the same as that of the brake control device 10 according to the first embodiment, it will be omitted as appropriate in the following description.

  As shown in FIG. 9, the ECU 300 in the brake control device according to the third embodiment is based on the pressure fluctuation of the working fluid detected by the cylinder pressure sensor 44 instead of the pressure fluctuation calculation unit 204 in the first embodiment. The air mixing determination unit 206 that determines whether or not air is mixed in the working fluid, and the pressure of the working fluid detected by the cylinder pressure sensor 44 when the air mixing determination unit determines that air is mixed. The difference is that it has an air mixing amount calculation unit 207 that calculates the amount of air mixed in the working fluid based on the fluctuation.

First, how the air mixing amount is calculated will be described. When air is mixed in the working fluid as shown in FIG. 5, a response delay occurs with respect to the target pressure. However, this response delay has a correlation with the air mixing amount, and the air mixing amount can be calculated from the relationship. In this embodiment, focusing on the response delay duration T ₁ as the time during which the response delay of the working fluid pressure with respect to the target pressure calculated according to the required braking force exceeds a predetermined reference deviation, the amount of air mixed in Is calculated. The response delay duration T ₁ is a time during which the response delay d ₁ shown in FIG. 5 continues for a predetermined threshold of 300 ms or more, which is a reference deviation, and the response delay duration T ₁ = t ₂ −t _1. Can be obtained. Here, t ₁ and t ₂ are times when the response delay of the line P3 is 300 ms. Further, the response delay time duration T ₁ is also dependent on the increase gradient of the target pressure.

Figure 10 is a graph showing the relationship between the mixing amount and the response delay duration T ₁ and the target pressure gradient ΔP of the air from the findings described above. Response delay duration T ₁ may vary the configuration of the brake system, a few hundred ms. Further, as shown in FIG. 10, the response delay time duration T ₁ is different if the air mixing quantity target pressure gradient even the same differences, also increases the response delay duration The more air intrusion amount. In FIG. 10, the air mixing amount Y indicated by the dotted line is larger than the air mixing amount X indicated by the solid line. Note that the failure detection line indicated by the alternate long and short dash line is a case where a delay in response occurs due to an abnormality in the hardware of pumps, valves, etc. that make up the brake device, or an abnormality in the control unit that controls the brake device, rather than air contamination. It is a threshold value for detecting those faults.

  Therefore, if the relationship shown in FIG. 10 is stored as a map in a storage unit (not shown), not only the air is mixed into the working fluid but also the amount of air mixed can be calculated. Hereinafter, with reference to FIG. 11, the air mixing determination and the air mixing amount calculation processing according to the third embodiment will be described.

  As shown in FIG. 11, when a brake request is generated and the processing of this embodiment is started, the ECU 300 sets the target pressure of each wheel cylinder 20 in the pressure setting unit 202 (S30). Next, the ECU 300 controls the pressure increasing valve 40 and, if necessary, the pressure reducing valve 42 by the valve control unit 201 based on the target pressure, so that the working fluid pressure in each wheel cylinder becomes the target pressure. A working fluid such as brake fluid delivered by the oil pump 34 is supplied to each wheel cylinder 20 (S32). At that time, a signal from the cylinder pressure sensor 44 indicating the measured value of the working fluid pressure acting on the wheel cylinder 20 is received (S34).

Air intrusion determination unit 206, in the same manner as in the first embodiment calculates the amplitude _{A 1} of the working fluid pressure in the booster (S36), and compares it with a predetermined threshold value _{A 0} (S38). When the amplitude A ₁ > A ₀ (Yes in S38), it is determined that air is mixed into the working fluid (S40). In that case, the air mixing amount calculation unit 207 calculates the response delay d ₁ of the pressure fluctuation of the detected working fluid pressure with respect to the target pressure (S42), and calculates the response delay duration T ₁ using the response delay d _1. (S44). Furthermore, using the map shown in FIG. 10, to calculate the air intrusion amount based on the response delay time duration T ₁ and the target pressure gradient [Delta] P (S46). And the warning to a passenger | crew can be performed by transmitting the information of the air mixing amount to the alerting | reporting part 205 (S48). The result may be transmitted together with the warning or instead of the warning to the pressure setting unit 202 or the valve control unit 201 for setting the control condition in the brake control.

On the other hand, when the amplitude A ₁ ≦ A ₀ (No in S38), it is determined that there is no air mixture in the working fluid at this time (S50). In this case, it is not necessary to calculate the air mixing amount, but there is a response delay due to abnormalities in hardware such as pumps and valves constituting the brake device as well as in the control unit that controls the brake device as described above. There is. Therefore, it is possible to detect a failure of them rather than contamination of the air by using a response delay duration T _1. In this embodiment, the response delay d ₁ of the pressure fluctuation of the detected working fluid pressure with respect to the target pressure is calculated (S52), and the response delay duration T ₁ is calculated using the response delay d ₁ (S54). Then, comparing the determined fault line _{T 0} or failure or not (S56). The failure detection line T _{0 according} to this embodiment is set to 360 ms.

Here, when the response delay duration T ₁ > T ₀ (Yes in S56), the occupant can be warned by transmitting the result to the notification unit 205 as a failure of the hardware or the control unit (S58). ). On the other hand, when the response delay duration T ₁ ≦ T ₀ , it is determined that there is no abnormality in the brake control device, and the process is terminated.

The failure detection line T ₀ may be masked so as not to function when determining the amount of air contamination when it is determined in step S38 that air is present. Depending on the air mixing amount, the response delay duration T ₁ may be longer than the failure detection line T ₀ , and it is possible to avoid erroneous detection of a hardware or control unit failure.

  As described above, according to the air mixing determination and the air mixing amount calculation processing according to the present embodiment, not only the air mixing amount can be calculated, but also a hardware or control unit failure when air is not mixed is detected. be able to. Therefore, it is possible to accurately determine the response delay between the response delay due to air mixing and the failure of the hardware or the control unit.

In step S38, the had to determine the air mixed into the amplitude A ₁ of the used working fluid pressure variations, air to the working fluid by using a response delay at the time of buck described in the second embodiment You may determine mixing of.

(Fourth embodiment)
The viscosity of brake oil or the like as a working fluid used in the brake control device varies depending on the temperature. In general, the viscosity increases at low temperatures and decreases at high temperatures. Therefore, the speed of passing through the orifice of a valve such as a linear valve varies depending on the temperature, and the response delay varies depending on the temperature. FIG. 12 is a diagram for explaining the difference in response delay due to the temperature of the working fluid.

FIG. 12 is a diagram for explaining the difference in response delay due to the temperature of the working fluid. As shown in FIG. 12, the response delay varies depending on the temperature of the working fluid regardless of whether air is mixed. Specifically, the response delay d _L at low temperature with high viscosity is larger than the response delay d _R at low temperature with low viscosity. FIG. 13 is a diagram showing an example of the relationship between the temperature of the working fluid and the delay time. As shown in FIG. 13, as the temperature of the working fluid rises, for example, the response delay increases even if the target pressure gradient ΔP is constant.

  Therefore, the predetermined threshold value 300 ms used as the predetermined reference deviation in the third embodiment is set to the temperature of the working fluid detected by the temperature sensor 62 (see FIG. 9) using the relationship map as shown in FIG. By setting accordingly, the air mixing amount can be calculated with higher accuracy.

(Fifth embodiment)
The brake control device according to this embodiment increases the opening of the valve at the time of boosting according to the presence or absence of air mixing and the air mixing amount determined in each of the above embodiments, thereby delaying response due to air mixing. Can be relaxed.

  Usually, when air is mixed, a response delay in a predetermined time after a braking request becomes particularly large. In addition, the response delay increases as the air mixing amount increases.

  Therefore, the brake control device according to the present embodiment is a pressure increasing valve that is set when there is no air mixing when the pressure fluctuation calculating unit 204 or the air mixing determining unit 206 determines that air is mixed in the working fluid. The valve control unit 201 controls the booster valve 40 so that the opening of the booster valve 40 becomes larger than the opening of 40 by a predetermined time after the braking request. Thereby, the response delay of the predetermined time after a braking request | requirement can be improved.

  Further, based on the air mixing amount calculated by the air mixing amount calculation unit 207, the opening of the pressure increasing valve 40 is larger for a predetermined time after the braking request than the opening of the pressure increasing valve 40 set when there is no air mixing. Thus, the valve control unit 201 controls the pressure increasing valve 40. Thereby, the response delay of a predetermined time after the braking request can be improved with higher accuracy.

(Sixth embodiment)
The brake control device according to the present embodiment keeps the working fluid pressure higher than usual in accordance with the presence / absence of air mixing and the amount of air mixing determined in each of the above embodiments, thereby delaying response due to air mixing. Can be relaxed.

  Usually, when air is mixed, a response delay in a predetermined time after a braking request becomes particularly large. In addition, the response delay increases as the air mixing amount increases.

  Therefore, the brake control device according to the present embodiment controls the brake in a state where the brake operation is not performed when the pressure fluctuation calculation unit 204 or the air mixing determination unit 206 determines that air is mixed in the working fluid. The pressure reducing valve 42 is controlled so that the pressure of the working fluid acting on the wheel cylinder 20 is maintained at a predetermined pressure so that no power is generated. Thereby, the response delay of the predetermined time after a braking request | requirement can be improved.

  Further, when the brake operation is not performed, the pressure of the working fluid acting on the wheel cylinder 20 is set to a predetermined pressure based on the air mixing amount calculated by the air mixing amount calculation unit 207 to the extent that no braking force is generated. The pressure reducing valve 42 is controlled so as to be maintained at the above. Thereby, the response delay of a predetermined time after the braking request can be improved with higher accuracy.

  In the above, this invention was demonstrated based on each embodiment. It is to be understood by those skilled in the art that these embodiments are exemplifications, and various modifications can be made to each component and process combination, and such modifications are also within the scope of the present invention. Such modifications will be described below.

  The air mixing determination process and the air mixing amount calculation process described above may be performed at any time while the vehicle is traveling. As a result, it is possible to increase the measurement opportunities and detect air contamination at an early stage and improve the determination accuracy. In addition, optimal brake control using the result can be performed.

  Alternatively, the air mixing determination process and the air mixing amount calculation process may be performed when the driver is stepping on when the vehicle is stopped. Since it is not necessary to calculate the required braking force when the vehicle is stopped and a predetermined target pressure gradient that is set in advance is used, it is possible to improve the accuracy of determining the presence or absence of air mixing and the amount of air mixing.

It is a distribution diagram showing a brake control device concerning an embodiment. It is sectional drawing which shows typically the cross section of a normally closed linear valve. It is sectional drawing which shows the cross section of a normally open type linear valve typically. It is a control block diagram of the brake control device concerning a 1st embodiment. It is a figure which shows the pressure fluctuation of the working fluid at the time of the braking request | requirement which concerns on 1st Embodiment. It is the figure which showed typically the pressure fluctuation which detected the state which the air mixed in the working fluid collapsed and the pulsation has generate | occur | produced by the pressure detection means. It is a flowchart for demonstrating the air mixing determination process in 1st Embodiment. It is a figure which shows the pressure fluctuation of the working fluid at the time of completion | finish of the braking request | requirement based on 2nd Embodiment. It is a control block diagram of a brake control device according to a third embodiment. It is the graph which showed the relationship between the response delay continuation time when air was mixed, and the target pressure gradient. It is a flowchart for demonstrating the air mixing determination and air mixing amount calculation processing which concern on 3rd Embodiment. It is a figure for demonstrating the difference in the response delay by the temperature of a working fluid. It is the figure which showed an example of the relationship between the temperature of a working fluid, and delay time.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Brake control apparatus, 20 Wheel cylinder, 32 Motor, 34 Oil pump, 40 Pressure increase valve, 42 Pressure reduction valve, 44 Cylinder pressure sensor, 46 Stroke sensor, 62 Temperature sensor, 200 ECU, 201 Valve control part, 202 Pressure setting part, 203 required braking force calculation unit, 204 pressure fluctuation calculation unit, 205 notification unit, 206 air mixing determination unit, 207 air mixing amount calculation unit, 300 ECU.

Claims (13)

In a brake control device for controlling a braking force applied to a wheel provided in a vehicle,
A valve that is connected via a flow path to a wheel cylinder that is supplied with a working fluid and applies a braking force to the wheel, and that adjusts the pressure of the working fluid acting on the wheel cylinder;
Pressure detecting means for detecting the pressure of the working fluid supplied to the wheel cylinder;
An air mixing determination unit that determines whether air is mixed in the working fluid based on the pressure fluctuation of the working fluid detected by the pressure detection unit;
Air mixture amount calculation for calculating the amount of air mixed in the working fluid based on the pressure fluctuation of the working fluid detected by the pressure detection means when the air mixing determination unit determines that air is mixed And
Equipped with a,
The air mixing amount calculation unit is configured to perform air based on a time during which a response delay of the pressure of the working fluid with respect to a target pressure calculated according to a required braking force exceeds a predetermined reference deviation, and a gradient of the target pressure. A brake control device that calculates a mixing amount .   2. The brake according to claim 1, wherein the air mixing determination unit determines whether air is mixed in the working fluid based on an amplitude of a pressure fluctuation at the time of pressurization of the working fluid after a braking request. Control device.   The air mixing determination unit is configured to detect air based on a comparison between the detected pressure of the working fluid and a reference pressure that is a reference for air mixing determination when the working fluid acting on the wheel cylinder after the braking request is finished. The brake control device according to claim 1, wherein it is determined whether or not it is mixed in the working fluid. The brake control device according to any one of claims 1 to 3, wherein the predetermined reference deviation is set according to a temperature of the working fluid. In a brake control device for controlling a braking force applied to a wheel provided in a vehicle,
A valve that is connected via a flow path to a wheel cylinder that is supplied with a working fluid and applies a braking force to the wheel, and that adjusts the pressure of the working fluid acting on the wheel cylinder;
Pressure detecting means for detecting the pressure of the working fluid supplied to the wheel cylinder;
An air mixing determination unit that determines whether air is mixed in the working fluid based on the pressure fluctuation of the working fluid detected by the pressure detection unit;
Air mixture amount calculation for calculating the amount of air mixed in the working fluid based on the pressure fluctuation of the working fluid detected by the pressure detection means when the air mixing determination unit determines that air is mixed And
And a valve control unit for controlling the opening of the valve,
The air mixing determination unit determines whether air is mixed in the working fluid based on the amplitude of pressure fluctuation at the time of pressurization of the working fluid after the braking request,
When the air mixing determination unit determines that the air is mixed in the working fluid, the valve control unit determines whether the valve has been operated for a predetermined time after a braking request based on the valve opening set when there is no air mixing. features and be Lube rake controller that controls the valve so that the opening is increased.   In a brake control device for controlling a braking force applied to a wheel provided in a vehicle,
  A valve that is connected via a flow path to a wheel cylinder that is supplied with a working fluid and applies a braking force to the wheel, and that adjusts the pressure of the working fluid acting on the wheel cylinder;
  Pressure detecting means for detecting the pressure of the working fluid supplied to the wheel cylinder;
  An air mixing determination unit that determines whether air is mixed in the working fluid based on the pressure fluctuation of the working fluid detected by the pressure detection unit;
  Air mixture amount calculation for calculating the amount of air mixed in the working fluid based on the pressure fluctuation of the working fluid detected by the pressure detection means when the air mixing determination unit determines that air is mixed And
  A valve control unit for controlling the opening of the valve,
  The air mixing determination unit is configured to detect air based on a comparison between the detected pressure of the working fluid and a reference pressure that is a reference for air mixing determination when the working fluid acting on the wheel cylinder after the braking request is finished. Determine whether it is mixed in the working fluid,
  When the air mixing determination unit determines that the air is mixed in the working fluid, the valve control unit determines whether the valve has been operated for a predetermined time after a braking request based on the valve opening set when there is no air mixing. A brake control device that controls the valve so as to increase an opening degree. In a brake control device for controlling a braking force applied to a wheel provided in a vehicle,
A valve that is connected via a flow path to a wheel cylinder that is supplied with a working fluid and applies a braking force to the wheel, and that adjusts the pressure of the working fluid acting on the wheel cylinder;
Pressure detecting means for detecting the pressure of the working fluid supplied to the wheel cylinder;
An air mixing determination unit that determines whether air is mixed in the working fluid based on the pressure fluctuation of the working fluid detected by the pressure detection unit;
Air mixture amount calculation for calculating the amount of air mixed in the working fluid based on the pressure fluctuation of the working fluid detected by the pressure detection means when the air mixing determination unit determines that air is mixed And
And a valve control unit for controlling the opening of the valve,
The air mixing determination unit determines whether air is mixed in the working fluid based on the amplitude of pressure fluctuation at the time of pressurization of the working fluid after the braking request,
Based on the air mixing amount calculated by the air mixing amount calculation unit, the valve control unit increases the valve opening for a predetermined time after a braking request than the valve opening set when there is no air mixing. features and be Lube rake controller that controls the valve so. In a brake control device for controlling a braking force applied to a wheel provided in a vehicle,
  A valve that is connected via a flow path to a wheel cylinder that is supplied with a working fluid and applies a braking force to the wheel, and that adjusts the pressure of the working fluid acting on the wheel cylinder;
  Pressure detecting means for detecting the pressure of the working fluid supplied to the wheel cylinder;
  An air mixing determination unit that determines whether air is mixed in the working fluid based on the pressure fluctuation of the working fluid detected by the pressure detection unit;
  Air mixture amount calculation for calculating the amount of air mixed in the working fluid based on the pressure fluctuation of the working fluid detected by the pressure detection means when the air mixing determination unit determines that air is mixed And
  A valve control unit for controlling the opening of the valve,
  The air mixing determination unit is configured to detect air based on a comparison between the detected pressure of the working fluid and a reference pressure that is a reference for air mixing determination when the working fluid acting on the wheel cylinder after the braking request is finished. Determine whether it is mixed in the working fluid,
  Based on the air mixing amount calculated by the air mixing amount calculation unit, the valve control unit increases the valve opening for a predetermined time after a braking request than the valve opening set when there is no air mixing. The brake control device characterized by controlling the valve so as to become. In a brake control device for controlling a braking force applied to a wheel provided in a vehicle,
A valve that is connected via a flow path to a wheel cylinder that is supplied with a working fluid and applies a braking force to the wheel, and that adjusts the pressure of the working fluid acting on the wheel cylinder;
Pressure detecting means for detecting the pressure of the working fluid supplied to the wheel cylinder;
An air mixing determination unit that determines whether air is mixed in the working fluid based on the pressure fluctuation of the working fluid detected by the pressure detection unit;
Air mixture amount calculation for calculating the amount of air mixed in the working fluid based on the pressure fluctuation of the working fluid detected by the pressure detection means when the air mixing determination unit determines that air is mixed And
And a valve control unit for controlling the opening of the valve,
The air mixing determination unit determines whether air is mixed in the working fluid based on the amplitude of pressure fluctuation at the time of pressurization of the working fluid after the braking request,
When the air mixing determination unit determines that air is mixed in the working fluid, the valve control unit acts on the wheel cylinder to the extent that no braking force is generated when no brake operation is performed. features and be Lube rake controller to control the valve to maintain the pressure of the working fluid at a predetermined pressure.   In a brake control device for controlling a braking force applied to a wheel provided in a vehicle,
  A valve that is connected via a flow path to a wheel cylinder that is supplied with a working fluid and applies a braking force to the wheel, and that adjusts the pressure of the working fluid acting on the wheel cylinder;
  Pressure detecting means for detecting the pressure of the working fluid supplied to the wheel cylinder;
  An air mixing determination unit that determines whether air is mixed in the working fluid based on the pressure fluctuation of the working fluid detected by the pressure detection unit;
  Air mixture amount calculation for calculating the amount of air mixed in the working fluid based on the pressure fluctuation of the working fluid detected by the pressure detection means when the air mixing determination unit determines that air is mixed And
  A valve control unit for controlling the opening of the valve,
  The air mixing determination unit is configured to detect air based on a comparison between the detected pressure of the working fluid and a reference pressure that is a reference for air mixing determination when the working fluid acting on the wheel cylinder after the braking request is finished. Determine whether it is mixed in the working fluid,
  When the air mixing determination unit determines that air is mixed in the working fluid, the valve control unit acts on the wheel cylinder to the extent that no braking force is generated when no brake operation is performed. A brake control device that controls the valve so as to maintain the pressure of the working fluid at a predetermined pressure. In a brake control device for controlling a braking force applied to a wheel provided in a vehicle,
A valve that is connected via a flow path to a wheel cylinder that is supplied with a working fluid and applies a braking force to the wheel, and that adjusts the pressure of the working fluid acting on the wheel cylinder;
Pressure detecting means for detecting the pressure of the working fluid supplied to the wheel cylinder;
An air mixing determination unit that determines whether air is mixed in the working fluid based on the pressure fluctuation of the working fluid detected by the pressure detection unit;
Air mixture amount calculation for calculating the amount of air mixed in the working fluid based on the pressure fluctuation of the working fluid detected by the pressure detection means when the air mixing determination unit determines that air is mixed And
And a valve control unit for controlling the opening of the valve,
The air mixing determination unit determines whether air is mixed in the working fluid based on the amplitude of pressure fluctuation at the time of pressurization of the working fluid after the braking request,
Based on the air mixing amount calculated by the air mixing amount calculation unit, the valve control unit is a pressure of the working fluid that acts on the wheel cylinder to the extent that no braking force is generated in a state where the brake operation is not performed. the characteristics and be Lube rake controller to control the valve to maintain a predetermined pressure.   In a brake control device for controlling a braking force applied to a wheel provided in a vehicle,
  A valve that is connected via a flow path to a wheel cylinder that is supplied with a working fluid and applies a braking force to the wheel, and that adjusts the pressure of the working fluid acting on the wheel cylinder;
  Pressure detecting means for detecting the pressure of the working fluid supplied to the wheel cylinder;
  An air mixing determination unit that determines whether air is mixed in the working fluid based on the pressure fluctuation of the working fluid detected by the pressure detection unit;
  Air mixture amount calculation for calculating the amount of air mixed in the working fluid based on the pressure fluctuation of the working fluid detected by the pressure detection means when the air mixing determination unit determines that air is mixed And
  A valve control unit for controlling the opening of the valve,
  The air mixing determination unit is configured to detect air based on a comparison between the detected pressure of the working fluid and a reference pressure that is a reference for air mixing determination when the working fluid acting on the wheel cylinder after the braking request is finished. Determine whether it is mixed in the working fluid,
  Based on the air mixing amount calculated by the air mixing amount calculation unit, the valve control unit is a pressure of the working fluid that acts on the wheel cylinder to the extent that no braking force is generated in a state where the brake operation is not performed. A brake control device that controls the valve so as to maintain the pressure at a predetermined pressure.   The air mixing determination unit determines that air is mixed in the working fluid when a response delay of the pressure of the working fluid with respect to the reference pressure is larger than a predetermined threshold value. The brake control device according to any one of 8, 10, and 12.

Images