JP2008120105A - Brake controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correctly determine whether an adhesion abnormality occurs in an accumulator pressure sensor. <P>SOLUTION: In this brake controller 200, an accumulator pressure control portion 84 controls the operation of a motor 36a driving a pump so as to bring detected accumulator pressure within a predetermined pressure range. A boost pressure linear control valve 66 is provided in a communicating passage connecting an accumulator and a wheel cylinder, and by opening and closing the boost pressure linear control valve 66, the supply and the stop of the supply of a hydraulic liquid from the accumulator to the wheel cylinder are switched. A sensor abnormality determining portion 88 determines whether the accumulator pressure sensor 72 is abnormal or not on the basis of the accumulator pressure detected when the boost pressure linear control valve 66 is opened so as to decrease the accumulator pressure to lower pressure than a lower limit value of the predetermined pressure range. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a brake control device, and more particularly to a brake control device that determines whether or not an accumulator pressure sensor that detects an accumulator pressure that is a working hydraulic pressure of an accumulator is abnormal.

As a braking system for vehicles such as automobiles, as described in Patent Document 1, for example, the accumulator pressure is maintained within a predetermined pressure range using the detection result of the accumulator pressure sensor, and the hydraulic fluid is transferred from the accumulator to the wheel cylinder. There is known a hydraulic brake system that increases the wheel cylinder pressure by supplying.
JP 2005-35471 A

  In such a hydraulic brake system, it is always required that an accurate accumulator pressure is output from the accumulator pressure sensor. However, in actuality, the accumulator pressure sensor may cause a sticking abnormality that outputs a certain detection value even though the accumulator pressure is changed. Among such sticking abnormalities, for example, when a sticking abnormality that outputs a constant detection value lower than the lower limit value of a predetermined pressure range where the accumulator pressure should be maintained occurs in the accumulator pressure sensor, the accumulator pressure increases. By determining whether or not the detection value of the accumulator pressure sensor also increases, it is possible to determine whether or not a sticking abnormality has occurred in the accumulator pressure sensor.

  However, when a sticking abnormality occurs that outputs a constant detection value within a predetermined pressure range in which the accumulator pressure should be maintained, for example, when the accumulator pressure drops to a pressure lower than the lower limit value of the predetermined pressure range. However, since the accumulator pressure is within a predetermined pressure range to be maintained in appearance, the hydraulic brake system disclosed in Patent Document 1 does not increase the accumulator pressure. For this reason, when such a sticking abnormality occurs, it is difficult to determine whether or not a sticking abnormality has occurred in the accumulator pressure sensor based on whether the detection value of the accumulator pressure sensor increases as the accumulator pressure increases. is there.

  The present invention has been made in view of these problems, and an object thereof is to accurately determine whether or not a sticking abnormality has occurred in an accumulator pressure sensor.

  In order to solve the above-described problems, a brake control device according to an aspect of the present invention includes an accumulator pressure sensor that detects an accumulator pressure that is a working hydraulic pressure of an accumulator that accumulates pressure when a pump is driven, and an accumulator pressure that is detected. The accumulator pressure control means for controlling the operation of the motor that drives the pump and the communication path connecting the accumulator and the wheel cylinder are provided so as to be within a predetermined pressure range, and from the accumulator by opening and closing the valve. A hydraulic control valve that switches between supplying and stopping the supply of hydraulic fluid to the wheel cylinder, and an accumulator detected when the hydraulic control valve is opened so that the accumulator pressure is lower than the lower limit value of the predetermined pressure range. Sensor abnormality determination hand that determines whether the accumulator pressure sensor is abnormal based on pressure And, equipped with a.

  If a sticking abnormality has occurred in the accumulator pressure sensor, the accumulator pressure remains in the predetermined pressure range even if the accumulator pressure is lower than the lower limit value of the predetermined pressure range by opening the hydraulic pressure control valve in this way. It is considered that it was not detected that the pressure was lower than the lower limit value. According to this aspect, it is possible to accurately determine whether or not a sticking abnormality has occurred in the accumulator pressure sensor using the detection value of the accumulator pressure sensor when the hydraulic pressure control valve is opened as described above. it can.

  A brake control device according to an aspect of the present invention supplies a differential pressure between an accumulator pressure and a wheel cylinder pressure, which is a working hydraulic pressure of a wheel cylinder, to the hydraulic pressure control valve to open the hydraulic pressure control valve. You may further provide the memory | storage part which stores the current differential pressure characteristic which shows the relationship with a power value. The sensor abnormality determining means determines the current value to be supplied to the hydraulic pressure control valve in order to make the accumulator pressure lower than the lower limit value of the predetermined pressure range with reference to the stored current differential pressure characteristic. Whether or not the accumulator pressure sensor is abnormal may be determined based on the accumulator pressure detected when the current having the current value is supplied from the battery.

  In general, the relationship between the differential pressure and the valve opening current of the hydraulic control valve in order to properly open the hydraulic control valve even when the differential pressure between the accumulator pressure and the wheel cylinder pressure varies. Is obtained and stored in advance in a storage unit provided in the vehicle. According to this aspect, it is possible to easily determine the current value to be supplied to the hydraulic pressure control valve in order to make the accumulator pressure lower than the lower limit value of the predetermined pressure range by referring to this current differential pressure specification. it can.

  If the accumulator pressure within the predetermined pressure range is detected when the hydraulic pressure control valve is opened to make the accumulator pressure lower than the lower limit value of the predetermined pressure range, the sensor abnormality determination means May be determined to be abnormal. According to this aspect, even when a sticking abnormality that outputs a detection value within a predetermined pressure range occurs in the accumulator pressure sensor, the occurrence of such a sticking abnormality can be detected.

  A brake control device according to an aspect of the present invention includes a control valve abnormality determination unit that determines whether or not a hydraulic pressure control valve is abnormal based on an operating state of the hydraulic pressure control valve when a current for opening the valve is supplied. May be further provided. The sensor abnormality determining means detects an accumulator pressure within a predetermined pressure range when the hydraulic pressure control valve is opened to make the accumulator pressure lower than a lower limit value of the predetermined pressure range. If it is determined that the accumulator pressure sensor is normal, it may be determined that the accumulator pressure sensor is abnormal.

  When the accumulator pressure is lower than the lower limit of the predetermined pressure range, but the accumulator pressure is detected by the accumulator pressure sensor, abnormalities in the accumulator pressure sensor and liquid Both abnormalities of the pressure control valve are considered. According to this aspect, it is possible to more accurately determine whether or not a sticking abnormality has occurred in the accumulator pressure sensor in consideration of these two factors.

  The brake control device according to an aspect of the present invention is configured so that the relay that switches on and off the operation of the motor that drives the pump is abnormal based on a response of the relay when a control current that turns on the operation of the motor is applied. It may further comprise relay abnormality determining means for determining whether or not. The relay abnormality determining means determines whether or not the relay is abnormal when the accumulator pressure is lower than a lower limit value of a predetermined pressure range so that the sensor abnormality determining means determines whether the accumulator pressure sensor is abnormal. Also good.

  When the above-described sticking abnormality determination is performed, the accumulator pressure decreases, so that it is necessary to operate the motor to increase the accumulator pressure. According to this aspect, it is possible to detect abnormality of the relay that switches on / off of the operation of the motor using this opportunity. For this reason, the abnormality detection of both the accumulator pressure sensor and the relay can be performed in one abnormality detection process, and the abnormality detection process can be simplified.

  According to the brake control device of the present invention, it is possible to accurately determine whether or not a sticking abnormality has occurred in the accumulator pressure sensor.

  Hereinafter, embodiments of the present invention (hereinafter referred to as “embodiments”) will be described in detail with reference to the drawings.

  FIG. 1 is a system diagram of a hydraulic brake system 20 provided in the brake control device 200 according to the present embodiment. The brake control device 200 includes a hydraulic brake system 20 and a brake electronic control unit (hereinafter referred to as “brake ECU”) 70. As shown in FIG. 1, the hydraulic brake system 20 includes disc brake units 21FR, 21FL, 21RR and 21RL provided for each wheel, a master cylinder unit 27, a power hydraulic pressure source 30, and a hydraulic brake system. Pressure actuator 40.

  Disc brake units 21FR, 21FL, 21RR, and 21RL apply braking force to the right front wheel, the left front wheel, the right rear wheel, and the left rear wheel of the vehicle, respectively. The master cylinder unit 27 as a manual hydraulic pressure source sends brake fluid as hydraulic fluid pressurized according to the amount of operation by the driver of the brake pedal 24 as a brake operation member to the disc brake units 21FR to 21RL. To do. The power hydraulic pressure source 30 can send the brake fluid pressurized by the power supply to the disc brake units 21FR to 21RL independently from the operation of the brake pedal 24 by the driver. The hydraulic actuator 40 appropriately adjusts the hydraulic pressure of the brake fluid supplied from the power hydraulic pressure source 30 or the master cylinder unit 27 and sends it to the disc brake units 21FR to 21RL. Thereby, the braking force with respect to each wheel by hydraulic braking is adjusted.

  Each of the disc brake units 21FR to 21RL, the master cylinder unit 27, the power hydraulic pressure source 30, and the hydraulic actuator 40 will be described in more detail below. Each of the disc brake units 21FR to 21RL includes a brake disc 22 and wheel cylinders 23FR to 23RL incorporated in the brake caliper, respectively. The wheel cylinders 23FR to 23RL are connected to the hydraulic actuator 40 via different fluid passages. Hereinafter, the wheel cylinders 23FR to 23RL are collectively referred to as “wheel cylinders 23” as appropriate.

  In the disc brake units 21FR to 21RL, when brake fluid is supplied to the wheel cylinder 23 from the hydraulic actuator 40, a brake pad as a friction member is pressed against the brake disc 22 that rotates together with the wheel. Thereby, a braking force is applied to each wheel. In the present embodiment, the disc brake units 21FR to 21RL are used, but other braking force applying mechanisms including a wheel cylinder 23 such as a drum brake may be used.

  In this embodiment, the master cylinder unit 27 is a master cylinder with a hydraulic booster, and includes a hydraulic booster 31, a master cylinder 32, a regulator 33, and a reservoir. The hydraulic booster 31 is connected to the brake pedal 24, amplifies the pedal effort applied to the brake pedal 24, and transmits it to the master cylinder 32. When the brake fluid is supplied from the power hydraulic pressure source 30 to the hydraulic pressure booster 31 via the regulator 33, the pedal effort is amplified. The master cylinder 32 generates a master cylinder pressure having a predetermined boost ratio with respect to the pedal effort.

  A reservoir 34 for storing brake fluid is disposed above the master cylinder 32 and the regulator 33. The master cylinder 32 communicates with the reservoir 34 when the depression of the brake pedal 24 is released. On the other hand, the regulator 33 is in communication with both the reservoir 34 and the accumulator 35 of the power hydraulic pressure source 30, and the reservoir 34 is used as a low pressure source, the accumulator 35 is used as a high pressure source, and the hydraulic pressure is approximately equal to the master cylinder pressure. Is generated. Hereinafter, the hydraulic pressure in the regulator 33 is appropriately referred to as “regulator pressure”.

  The power hydraulic pressure source 30 includes an accumulator 35 and a pump 36. The accumulator 35 converts the pressure energy of the brake fluid, which has been increased by the pump 36, into pressure energy of an enclosed gas such as nitrogen, for example, about 14 to 22 MPa, and stores it. The pump 36 has a motor 36 a as a drive source, and its suction port is connected to the reservoir 34, while its discharge port is connected to the accumulator 35. The accumulator 35 is also connected to a relief valve 35 a provided in the master cylinder unit 27. When the pressure of the brake fluid in the accumulator 35 increases abnormally to about 25 MPa, for example, the relief valve 35 a is opened, and the high-pressure brake fluid is returned to the reservoir 34.

  As described above, the hydraulic brake system 20 includes the master cylinder 32, the regulator 33, and the accumulator 35 as a supply source of brake fluid to the wheel cylinder 23. A master pipe 37 is connected to the master cylinder 32, a regulator pipe 38 is connected to the regulator 33, and an accumulator pipe 39 is connected to the accumulator 35. These master pipe 37, regulator pipe 38 and accumulator pipe 39 are each connected to a hydraulic actuator 40.

  The hydraulic actuator 40 includes an actuator block in which a plurality of flow paths are formed, and a plurality of electromagnetic control valves. The flow paths formed in the actuator block include individual flow paths 41, 42, 43 and 44 and a main flow path 45. The individual flow paths 41 to 44 are respectively branched from the main flow path 45 and connected to the wheel cylinders 23FR, 23FL, 23RR, 23RL of the corresponding disc brake units 21FR, 21FL, 21RR, 21RL. Thereby, each wheel cylinder 23 can communicate with the main flow path 45.

  In addition, ABS holding valves 51, 52, 53 and 54 are provided in the middle of the individual flow paths 41, 42, 43 and 44. Each of the ABS holding valves 51 to 54 has a solenoid and a spring that are ON / OFF controlled, and both are normally open electromagnetic control valves that are opened when the solenoid is in a non-energized state. Each of the ABS holding valves 51 to 54 in the opened state can distribute the brake fluid in both directions. That is, the brake fluid can flow from the main flow path 45 to the wheel cylinder 23, and conversely, the brake fluid can also flow from the wheel cylinder 23 to the main flow path 45. When the solenoid is energized and the ABS holding valves 51 to 54 are closed, the flow of brake fluid in the individual flow paths 41 to 44 is blocked.

  Further, the wheel cylinder 23 is connected to the reservoir channel 55 via pressure reducing channels 46, 47, 48 and 49 connected to the individual channels 41 to 44, respectively. ABS decompression valves 56, 57, 58 and 59 are provided in the middle of the decompression channels 46, 47, 48 and 49. Each of the ABS pressure reducing valves 56 to 59 has a solenoid and a spring that are ON / OFF controlled, and is a normally closed electromagnetic control valve that is closed when the solenoid is in a non-energized state. When the ABS pressure reducing valves 56 to 59 are closed, the flow of brake fluid in the pressure reducing flow paths 46 to 49 is blocked. When the solenoid is energized and the ABS pressure reducing valves 56 to 59 are opened, the brake fluid is allowed to flow through the pressure reducing flow paths 46 to 49, and the brake fluid flows from the wheel cylinder 23 to the pressure reducing flow paths 46 to 49 and It returns to the reservoir 34 via the reservoir channel 55. The reservoir channel 55 is connected to the reservoir 34 of the master cylinder unit 27 via a reservoir pipe 77.

  The main channel 45 has a separation valve 60 in the middle. By this separation valve 60, the main channel 45 is divided into a first channel 45 a connected to the individual channels 41 and 42 and a second channel 45 b connected to the individual channels 43 and 44. The first flow path 45a is connected to the front wheel side wheel cylinders 23FR and 23FL via the individual flow paths 41 and 42, and the second flow path 45b is connected to the rear wheel side wheel cylinder via the individual flow paths 43 and 44. Connected to 23RR and 23RL.

  The separation valve 60 has a solenoid and a spring that are ON / OFF controlled, and is a normally closed electromagnetic control valve that is closed when the solenoid is in a non-energized state. When the separation valve 60 is in the closed state, the flow of brake fluid in the main flow path 45 is blocked. When the solenoid is energized and the separation valve 60 is opened, the brake fluid can be circulated bidirectionally between the first flow path 45a and the second flow path 45b.

  In the hydraulic actuator 40, a master channel 61 and a regulator channel 62 communicating with the main channel 45 are formed. More specifically, the master channel 61 is connected to the first channel 45 a of the main channel 45, and the regulator channel 62 is connected to the second channel 45 b of the main channel 45. The master channel 61 is connected to a master pipe 37 that communicates with the master cylinder 32. The regulator channel 62 is connected to a regulator pipe 38 that communicates with the regulator 33.

  The master channel 61 has a master cut valve 64 in the middle. The master cut valve 64 is provided on the brake fluid supply path from the master cylinder 32 to each wheel cylinder 23. The master cut valve 64 has a solenoid and a spring that are ON / OFF-controlled, and the valve closing state is guaranteed by the electromagnetic force generated by the solenoid when supplied with a prescribed control current, so that the solenoid is in a non-energized state. It is a normally open electromagnetic control valve that is opened in some cases. The master cut valve 64 in the opened state can cause the brake fluid to flow in both directions between the master cylinder 32 and the first flow path 45 a of the main flow path 45. When a prescribed control current is applied to the solenoid and the master cut valve 64 is closed, the flow of brake fluid in the master flow path 61 is interrupted.

  A stroke simulator 69 is connected to the master channel 61 via a simulator cut valve 68 on the upstream side of the master cut valve 64. That is, the simulator cut valve 68 is provided in a flow path connecting the master cylinder 32 and the stroke simulator 69. The simulator cut valve 68 is a normally closed electromagnetic control valve that has a solenoid and a spring that are ON / OFF controlled and is closed when the solenoid is in a non-energized state. When the simulator cut valve 68 is closed, the flow of brake fluid between the master flow path 61 and the stroke simulator 69 is blocked. When the solenoid is energized and the simulator cut valve 68 is opened, the brake fluid can be circulated bidirectionally between the master cylinder 32 and the stroke simulator 69.

  The stroke simulator 69 includes a plurality of pistons and springs, and creates a reaction force corresponding to the depression force of the brake pedal 24 by the driver when the simulator cut valve 68 is opened. As the stroke simulator 69, in order to improve the feeling of brake operation by the driver, it is preferable to employ one having a multistage spring characteristic.

  The regulator flow path 62 has a regulator cut valve 65 in the middle. The regulator cut valve 65 is provided on the brake fluid supply path from the regulator 33 to each wheel cylinder 23. The regulator cut valve 65 also has a solenoid and a spring that are controlled to be turned on and off, and the closed state is guaranteed by the electromagnetic force generated by the solenoid when supplied with a prescribed control current, so that the solenoid is turned off. It is a normally open electromagnetic control valve that is opened in some cases. The regulator cut valve 65 that has been opened can cause the brake fluid to flow in both directions between the regulator 33 and the second flow path 45 b of the main flow path 45. When the solenoid is energized and the regulator cut valve 65 is closed, the flow of brake fluid in the regulator flow path 62 is blocked.

  In the hydraulic actuator 40, an accumulator channel 63 is also formed in addition to the master channel 61 and the regulator channel 62. One end of the accumulator channel 63 is connected to the second channel 45 b of the main channel 45, and the other end is connected to an accumulator pipe 39 that communicates with the accumulator 35.

  The accumulator flow path 63 has a pressure-increasing linear control valve 66 in the middle. Further, the accumulator channel 63 and the second channel 45 b of the main channel 45 are connected to the reservoir channel 55 via the pressure-reducing linear control valve 67. The pressure-increasing linear control valve 66 and the pressure-decreasing linear control valve 67 each have a linear solenoid and a spring, and both are normally closed electromagnetic control valves that are closed when the solenoid is in a non-energized state. In the pressure-increasing linear control valve 66 and the pressure-decreasing linear control valve 67, the opening degree of the valve is adjusted in proportion to the current supplied to each solenoid.

  The pressure-increasing linear control valve 66 is provided as a common pressure-increasing control valve for each of the wheel cylinders 23 provided corresponding to each wheel. Similarly, the pressure reducing linear control valve 67 is provided as a pressure reducing control valve common to the wheel cylinders 23. That is, in this embodiment, the pressure-increasing linear control valve 66 and the pressure-reducing linear control valve 67 are a pair of common control valves that control the supply and discharge of the working fluid sent from the power hydraulic pressure source 30 to each wheel cylinder 23. It is provided as. If the pressure-increasing linear control valve 66 and the like are made common to each wheel cylinder 23 in this way, it is preferable from the viewpoint of cost as compared with the case where a linear control valve is provided for each wheel cylinder 23.

  In the hydraulic brake system 20, the power hydraulic pressure source 30 and the hydraulic actuator 40 are controlled by the brake ECU 70. The brake ECU 70 is configured as a microprocessor including a CPU, and includes a ROM that stores various programs, a RAM that temporarily stores data, an input / output port, a communication port, and the like in addition to the CPU. The brake ECU 70 can communicate with a host hybrid ECU (not shown) and the like, and based on control signals from the hybrid ECU and signals from various sensors, the pump 36 of the power hydraulic pressure source 30 and the hydraulic pressure Brake regeneration cooperative control can be executed by controlling the electromagnetic control valves 51 to 54, 56 to 59, 60, and 64 to 68 constituting the actuator 40.

  Further, a regulator pressure sensor 71, an accumulator pressure sensor 72, and a control pressure sensor 73 are connected to the brake ECU 70. The regulator pressure sensor 71 detects the pressure of the brake fluid in the regulator flow path 62 on the upstream side of the regulator cut valve 65, that is, the regulator pressure, and gives a signal indicating the detected value to the brake ECU 70. The accumulator pressure sensor 72 detects the pressure of the brake fluid in the accumulator flow path 63, that is, the accumulator pressure on the upstream side of the pressure increasing linear control valve 66, and gives a signal indicating the detected value to the brake ECU 70. The control pressure sensor 73 detects the pressure of the brake fluid in the first flow path 45a of the main flow path 45, and gives a signal indicating the detected value to the brake ECU 70. The detection values of the pressure sensors 71 to 73 are sequentially given to the brake ECU 70 every predetermined time, and are stored and held in a predetermined storage area of the brake ECU 70 by a predetermined amount.

  The separation valve 60 is open when the wheel cylinder pressure is controlled by the pressure-increasing linear control valve 66 and the pressure-decreasing linear control valve 67. At this time, the first flow path 45a and the second flow path 45b are the same. The pressure has become. Further, the ABS holding valves 51 to 54 are normally opened when the wheel cylinder pressure is controlled by the pressure increasing linear control valve 66 and the pressure reducing linear control valve 67. For this reason, the brake fluid pressure in the first flow path 45a and the second flow path 45b is the same as the wheel cylinder pressure. Therefore, in this case, the control pressure sensor 73 functions as a wheel cylinder pressure sensor that detects the wheel cylinder pressure of the wheel cylinder 23.

  Further, the sensor connected to the brake ECU 70 includes a stroke sensor 25 provided on the brake pedal 24. The stroke sensor 25 detects a pedal stroke as an operation amount of the brake pedal 24 and gives a signal indicating the detected value to the brake ECU 70. The output value of the stroke sensor 25 is also sequentially given to the brake ECU 70 every predetermined time, and is stored and held in a predetermined storage area of the brake ECU 70 by a predetermined amount. A brake operation state detection unit other than the stroke sensor 25 may be provided in addition to the stroke sensor 25 or in place of the stroke sensor 25 and connected to the brake ECU 70. Examples of the brake operation state detection means include a pedal depression force sensor that detects an operation force of the brake pedal 24 and a brake switch that detects that the brake pedal 24 is depressed.

  FIG. 2 is a functional block diagram of the brake control device 200 according to the present embodiment. In FIG. 2, the brake ECU 70 is a combination of hardware such as 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, and software. The functional blocks to be realized are drawn. Therefore, these functional blocks can be realized in various forms by a combination of hardware and software.

  The accumulator pressure sensor 72 and the control pressure sensor 73 are connected to the brake ECU 70. The detection results of the accumulator pressure sensor 72 and the control pressure sensor 73 are output to the brake ECU 70.

  The brake ECU 70 is connected to the pressure-increasing linear control valve 66 via the drive circuit 102. A brake control unit 82, which will be described later, determines a current value to be supplied to the pressure-increasing linear control valve 66 and its duty, and supplies it to the drive circuit 102 to supply current to the pressure-increasing linear control valve 66 with the determined current value and duty. Supply control current. The drive circuit 102 supplies a current from the battery 110 to the pressure-increasing linear control valve 66 with a current value and a duty corresponding to the input control current.

  Similarly, the brake ECU 70 is connected to the pressure-reducing linear control valve 67 via the drive circuit 104. The brake control unit 82 determines a current value to be supplied to the pressure reducing linear control valve 67 and its duty, and supplies a control current to the drive circuit 104 to supply current to the pressure reducing linear control valve 67 with the determined current value and duty. To do. The drive circuit 104 supplies a current from the battery 110 to the pressure-reducing linear control valve 67 with a current value and a duty corresponding to the input control current.

  The brake ECU 70 is connected to the motor 36 a via the first relay 106 and the second relay 108. An accumulator pressure control unit 84, which will be described later, controls on and off of the first relay 106 or the second relay 108 by supplying a control current to the first relay 106 or the second relay 108, and the battery 110 to the motor 36a is controlled. By controlling the supply and stop of the current, the operation and stop of the motor 36a are controlled.

  The second relay 108 is provided in case an abnormality occurs in the first relay 106. The accumulator pressure control unit 84 controls the operation of the motor 36a by turning on and off the first relay 106 when the first relay 106 is normal, and turns on and off the second relay 108 when an abnormality occurs in the first relay 106. Thus, the operation of the motor 36a is controlled.

  The brake ECU 70 includes a brake control unit 82, an accumulator pressure control unit 84, a learning control unit 86, a sensor abnormality determination unit 88, a valve abnormality determination unit 90, a relay abnormality determination unit 92, and a storage unit 94.

  The brake control unit 82 uses the detection results of the stroke sensor 25, the regulator pressure sensor 71, and the like to apply an appropriate braking force to each of the wheels provided on the vehicle. Calculate the pressure. The brake control unit 82 determines the current value and its duty that are required to be supplied to the pressure-increasing linear control valve 66 or the pressure-decreasing linear control valve 67 in order to generate the calculated wheel cylinder pressure. A control current corresponding to the current value and the duty is supplied to the drive circuit 102 or the drive circuit 104. The brake control unit 82 thus generates an appropriate wheel cylinder pressure for each of the wheel cylinders 23.

The accumulator pressure control unit 84 controls the accumulator pressure to be within a predetermined pressure range. Specifically, the accumulator pressure control unit 84 uses the detection result of the accumulator pressure sensor 72 to determine whether the accumulator pressure has decreased to a predetermined lower limit pressure (hereinafter referred to as “pump actuation accumulator pressure P _β ”). The first relay 106 or the second relay 108 is turned on to operate the motor 36a, and the accumulator pressure is increased. When the operation of the motor 36a is continued and the accumulator pressure reaches a predetermined upper limit pressure (hereinafter referred to as “pump stop accumulator pressure P _α ”), the accumulator pressure control unit 84 controls the first relay 106 or the second relay 108. The operation of the motor 36a is stopped by turning it off, and further increase in accumulator pressure is suppressed.

  The learning control unit 86 is a current indicating a relationship between a differential pressure between the accumulator pressure and the wheel cylinder pressure and a valve opening current for opening the pressure-increasing linear control valve 66 (hereinafter referred to as “valve opening current Is”). Implement learning control to acquire differential pressure characteristics. In addition, the learning control unit 86 performs learning control for acquiring current differential pressure specifying the relationship between the wheel cylinder pressure and the valve opening current for opening the pressure-reducing linear control valve 67. These learning controls are generally performed before the vehicle is shipped. The specific procedure of learning control is well known and will not be described. Of course, these learning controls may be performed after the vehicle is shipped.

  The storage unit 94 is a generic term for storage devices provided in the brake ECU 70, such as ROM, RAM, or other rewritable storage media. The learning control unit 86 stores a current differential pressure characteristic acquired by the learning control unit 86 performing learning control.

  The sensor abnormality determination unit 88 determines whether or not an abnormality has occurred in the accumulator pressure sensor 72. Here, although the accumulator pressure is actually changing, there may be a sticking abnormality in the accumulator pressure sensor 72 that outputs a constant accumulator pressure as a detection value. For example, when a sticking abnormality occurs in the accumulator pressure sensor 72 that outputs a constant pressure lower than the lower limit value of a predetermined pressure range in which the accumulator pressure is to be maintained as a detected value, the accumulator pressure control unit 84 first falls within the predetermined pressure range. The pump 36 is operated to increase the accumulator pressure. The sensor abnormality determination unit 88 determines whether or not the accumulator pressure detected by the accumulator pressure sensor 72 at this time increases with the operation of the pump 36, whereby a sticking abnormality occurs in the accumulator pressure sensor 72. It is possible to determine whether or not.

However, when a sticking abnormality occurs in the accumulator pressure sensor 72 that outputs a constant pressure within a predetermined pressure range in which the accumulator pressure should be maintained as a detected value, the accumulator pressure control unit 84 determines that the accumulator pressure is the pump operating accumulator pressure P. _It is determined that the pressure has not decreased to _β , and the pump 36 is not operated. In this case, it is difficult to determine whether or not a sticking abnormality has occurred in the accumulator pressure sensor 72 by the above-described determination method.

  Therefore, the sensor abnormality determination unit 88 according to the present embodiment is based on the accumulator pressure detected when the hydraulic pressure control valve is opened so that the accumulator pressure is lower than the lower limit value of the predetermined pressure range. It is determined whether or not the accumulator pressure sensor is abnormal. The procedure for determining the sticking abnormality of the accumulator pressure sensor 72 will be described in detail below with reference to FIG.

  The valve abnormality determination unit 90 determines whether or not an abnormality has occurred in all electromagnetic control valves provided in the hydraulic brake system 20 including the pressure-increasing linear control valve 66 and the pressure-decreasing linear control valve 67. Specifically, in the brake ECU 70, information indicating an energized state when a current is supplied from the battery 110 to the electromagnetic control valve to open the electromagnetic control valve is displayed in the drive circuit such as the drive circuit 102 and the drive circuit 104. It is input from. The valve abnormality determination unit 90 determines the operating state of each electromagnetic control valve using information indicating the energized state, and determines whether or not an abnormality has occurred for each electromagnetic control valve.

  The relay abnormality determination unit 92 determines whether or not the relay is abnormal. Specifically, the relay abnormality determination unit 92 is in a state where the first relay 106 or the second relay 108 is energized when a control current for turning on the operation of the motor 36a is applied to the first relay 106 or the second relay 108. It is determined whether the relay is abnormal based on the response.

  FIG. 3 is a flowchart illustrating an abnormality determination procedure for the accumulator pressure sensor and the like in the brake control device 200 according to the present embodiment. The processing in this flowchart is performed every predetermined time after the ignition switch of the vehicle is turned on. Note that the processing in this flowchart is not performed when the depression operation of the brake pedal 24 is detected by the stroke sensor 25. Further, when the depression operation of the brake pedal 24 is detected by the stroke sensor 25 while the process in the flowchart is being performed, the process in the flowchart is ended.

The brake control unit 82 supplies the abnormality detecting valve opening current _{I 1} to the pressure-increasing linear control valve (S10). Here, the method of determining the abnormality detection valve opening current I _1, will be described in connection with FIG.

FIG. 4 is a diagram showing the relationship between the accumulator pressure P _acc and the current value Is supplied to the pressure-increasing linear control valve 66. In FIG. 4, the horizontal axis represents the accumulator pressure P _acc , and the vertical axis represents the current value Is supplied to the pressure-increasing linear control valve 66. FIG. 4 shows a current differential pressure characteristic indicating the relationship between the differential pressure between the accumulator pressure and the wheel cylinder pressure and the valve opening current of the pressure-increasing linear control valve 66. As shown in FIG. 4, the current differential pressure characteristic in this case is a straight line in which the current value Is decreases as the accumulator pressure P _acc increases. The current difference pressure characteristics show original relationships between the differential pressure and the current value Is of the accumulator pressure P _acc and the wheel cylinder pressure rather than the relationship between the accumulator pressure P _acc and the current value Is, but abnormalities in this embodiment In the determination procedure, the brake pedal 24 is not depressed, and the wheel cylinder pressure is approximately equal to the atmospheric pressure. Therefore, the relationship between the accumulator pressure P _acc and the current value Is is shown in FIG.

FIG. 4 also shows a pump stop accumulator pressure P _α , a pump operation accumulator pressure P _β , and an accumulator pressure control range W _acc that is a pressure range therebetween. In the current difference pressure characteristics, the current value Is when the pump operation accumulator pressure P _beta and pumping valve opening current I _beta. Such as when the accumulator pressure is within the accumulator pressure control range W _acc, the accumulator pressure is supplied to the pump operating valve opening current I _beta in the pressure-increasing linear control valve 66 is greater than the pumping accumulator pressure P _beta, the accumulator pressure as the accumulator pressure by the pressure-increasing linear control valve 66 is closed when it reaches the pumping accumulator pressure P _beta continue to vacuum is maintained in the pump operation accumulator pressure P _beta. Therefore pumping valve opening current I _beta can be said that the pressure increase to be supplied to the linear control valve 66 current value Is to depressurize the accumulator pressure in the pump working accumulator pressure P _beta.

In this embodiment, the sensor abnormality determination section 88 first sets the abnormality detection accumulator pressure P ₁ is a pressure lower than the pump working accumulator pressure P _beta. Then sensor abnormality determination section 88 refers to the current difference pressure characteristics of the pressure-increasing linear control valve 66 stored in the storage unit 94, the accumulator pressure P _acc abnormality detection accumulator pressure P ₁ pressure-increasing linear control in order to A current value Is of the valve opening current to be supplied to the valve 66 is calculated. Sensor abnormality determination unit 88, thus determines the calculated current value Is to the abnormality detecting valve opening current I _1. Current difference pressure characteristics because the current value Is increases as the accumulator pressure is reduced, the abnormality detecting the valve opening current I ₁ becomes a value larger than pumping valve opening current I _beta. Sensor abnormality determination section 88 determines a current to be supplied to the pressure intensifying linear control valve 66 in order to depressurize the manner accumulator pressure pump operation accumulator pressure P lower pressures _beta.

  Returning to FIG. In S10, the brake control unit 82 opens the pressure-increasing linear control valve 66 and also opens the pressure-decreasing linear control valve 67. As a result, the wheel cylinder pressure is prevented from being increased, so that it is possible to perform abnormality determination processing for the accumulator pressure sensor 72 even when the vehicle is running, for example.

If the abnormality detecting valve opening current I ₁ to the pressure-increasing linear control valve 66 is supplied, if an accumulator pressure sensor 72 and the pressure-increasing linear control valve 66 are both normal, the accumulator pressure is lower than the pump operation the accumulator pressure P _beta abnormal it is reduced to detect the accumulator pressure P _1, an accumulator pressure sensor 72 should also detects an abnormality detection accumulator pressure P _1. Therefore, the abnormality detecting valve opening current I ₁ to the pressure-increasing linear control valve 66 is supplied, the sensor abnormality determination section 88, values detected by the accumulator pressure sensor 72 whether the smaller pump operation the accumulator pressure P _beta Determine (S12).

Even when the accumulator pressure P _acc is reduced to a pressure lower than the pump operating accumulator pressure P _β , the value detected by the accumulator pressure sensor 72 is determined to be equal to or higher than the pump operating accumulator pressure P _β (N in S12). There is a possibility that an abnormality has occurred in either the accumulator pressure sensor 72 or the pressure-increasing linear control valve 66. Therefore, the valve abnormality determination unit 90 supplies the abnormality detection valve opening current I ₁ to the pressure increase linear control valve 66 in order to clarify which of the pressure increase linear control valve 66 and the accumulator pressure sensor 72 is abnormal. Using the energized state of the pressure-increasing linear control valve 66 when supplied, it is determined whether or not the pressure-increasing linear control valve 66 is abnormal (S14). When the energization state of the pressure-increasing linear control valve 66 is abnormal, such as when the pressure-increasing linear control valve 66 is not energized (Y in S14), the valve abnormality determining unit 90 determines that an abnormality has occurred in the pressure-increasing linear control valve 66. (S16).

  When it is determined that an abnormality has occurred in the pressure-increasing linear control valve 66, the brake control unit 82 stops the electronic control of the braking force by the pressure-increasing linear control valve 66 and the pressure-decreasing linear control valve 67, and the master cylinder 32 and the regulator The method switches to a braking force generation method in which the pressure 33 is directly applied to the wheel cylinder 23.

  Specifically, when the sensor abnormality determination unit 88 determines that an abnormality has occurred in the pressure increase linear control valve 66, the brake control unit 82 closes the pressure increase linear control valve 66 and the pressure reduction linear control valve 67. The master cut valve 64 and the regulator cut valve 65 are opened, and the separation valve 60 is closed. As a result, the master cylinder pressure is applied to the right front wheel wheel cylinder 23FR and the left front wheel wheel cylinder 23FL, and the regulator pressure is applied to the right rear wheel wheel cylinder 23RR and the left rear wheel wheel cylinder 23RL.

  Furthermore, the brake ECU 70 transmits information indicating that an abnormality has occurred in the electronically controlled braking system for braking force to an integrated ECU (not shown), and the integrated ECU is a warning lamp provided on an instrument panel in the vehicle cabin. (Not shown) is lit to notify the vehicle occupant to that effect.

Although the accumulator pressure P _acc is reduced to a pressure lower than the pump operating accumulator pressure P _{β, the} value detected by the accumulator pressure sensor 72 becomes equal to or higher than the pump operating accumulator pressure P _β , and the pressure increasing linear control valve 66 is normal. When it is determined (N in S14), the sensor abnormality determination unit 88 determines that an abnormality has occurred in the accumulator pressure sensor 72 (S18). Even when it is determined that an abnormality has occurred in the accumulator pressure sensor 72, the brake control unit 82 stops the electronic control of the braking force by the pressure-increasing linear control valve 66 and the pressure-decreasing linear control valve 67 as described above, and the master cylinder The method switches to a braking force generation method that directly applies the pressure of the pressure regulator 32 and the regulator 33 to the wheel cylinder 23. Further, the integrated ECU turns on a warning lamp.

When the accumulator pressure P _acc is reduced to a pressure lower than the pump operating accumulator pressure P _{β and the} value detected by the accumulator pressure sensor 72 is also smaller than the pump operating accumulator pressure P _β (Y in S12), the accumulator pressure sensor 72 and the pressure increasing linear control Both valves 66 are considered normal. Therefore, the brake control unit 82 continues the electronic control of the braking force by the pressure increasing linear control valve 66 and the pressure reducing linear control valve 67 as it is.

Here, since the accumulator pressure by carrying out the abnormality determination of the accumulator pressure sensor 72 is reduced to the abnormality detection accumulator pressure P _1, the accumulator pressure control section 84, the accumulator pressure in the accumulator pressure control range W _acc In order to return, the operation of the pump 36 is started (S20).

Thus, in the abnormality determination control of the accumulator pressure sensor 72 according to this embodiment, the accumulator pressure since the pumping accumulator pressure P _beta lower pressures, and thus operating the motor 36a. For this reason, the brake control apparatus 200 according to the present embodiment also performs abnormality determination of the first relay 106 and the second relay 108 along with abnormality determination control of the accumulator pressure sensor 72.

  When the operation of the pump 36 is started, the relay abnormality determination unit 92 supplies a control current for switching on the first relay 106 to the first relay 106, and uses the energization state of the first relay 106 at this time. Then, it is determined whether or not the first relay 106 is normal (S22).

  When there is an abnormality in the energization state of the first relay 106, such as when the first relay 106 is not energized (N in S22), the relay abnormality determination unit 92 determines that an abnormality has occurred in the first relay 106 (S24). In this case, the storage unit 94 sets a flag indicating that an abnormality has occurred in the first relay 106. At this time, the brake ECU 70 may output information indicating that an abnormality has occurred in the first relay 106 to the integrated ECU, and the integrated ECU may turn on a warning lamp provided in the vehicle cabin.

  When the abnormality determination of the first relay 106 is completed (Y in S22, S24), the relay abnormality determination unit 92 supplies a control current for switching on the second relay 108 to the second relay 108. Whether the second relay 108 is normal is determined using the energization state of the second relay 108 (S26).

  When there is an abnormality in the energization state of the second relay 108, such as when the second relay 108 is not energized (N in S26), the relay abnormality determination unit 92 determines that an abnormality has occurred in the second relay 108 (S28). In this case, the storage unit 94 sets a flag indicating that an abnormality has occurred in the second relay 108. Further, the brake ECU 70 may output information indicating that an abnormality has occurred in the second relay 108 to the integrated ECU, and the integrated ECU may turn on a warning lamp provided in the vehicle cabin. When the abnormality determination of the second relay 108 is finished (Y in S26, S28), the processing in this flowchart is finished.

  The accumulator pressure control unit 84 refers to the flag relating to the abnormality of the first relay 106 and the flag relating to the abnormality of the second relay 108. If both the first relay 106 and the second relay 108 are normal, the motor 36a is turned off. When operating, the first relay 106 is turned on. When one of the first relay 106 and the second relay 108 is normal and the other is abnormal, the normal relay is turned on when the motor 36a is operated.

  When an abnormality occurs in both the first relay 106 and the second relay 108, the brake control unit 82 stops the electronic control of the braking force by the pressure increasing linear control valve 66 and the pressure reducing linear control valve 67, and the master cylinder 32 and The method switches to a braking force generation method in which the pressure of the regulator 33 is directly applied to the wheel cylinder 23. Further, the integrated ECU turns on a warning lamp.

It is a systematic diagram of the hydraulic brake system with which the brake control device concerning this embodiment is provided. It is a functional block diagram of a brake control device concerning this embodiment. It is a flowchart which shows abnormality determination procedures, such as an accumulator pressure sensor, in the brake control apparatus which concerns on this embodiment. It is a figure which shows the relationship between the accumulator pressure _Pacc and the electric current value Is supplied to a pressure increase linear control valve.

Explanation of symbols

  20 hydraulic brake system, 23 wheel cylinder, 35 accumulator, 36 pump, 36a motor, 66 pressure-increasing linear control valve, 67 pressure-decreasing linear control valve, 70 brake ECU, 72 accumulator pressure sensor, 73 control pressure sensor, 82 brake control unit 84, accumulator pressure control unit, 86 learning control unit, 88 sensor abnormality determination unit, 90 valve abnormality determination unit, 92 relay abnormality determination unit, 94 storage unit, 106 first relay, 108 second relay, 200 brake control device.

Claims (5)

An accumulator pressure sensor that detects an accumulator pressure that is a working hydraulic pressure of an accumulator that accumulates pressure when the pump is driven;
Accumulator pressure control means for controlling the operation of the motor that drives the pump so that the detected accumulator pressure is within a predetermined pressure range;
A fluid pressure control valve that is provided in a communication path connecting the accumulator and the wheel cylinder, and that switches between supply and stop of supply of hydraulic fluid from the accumulator to the wheel cylinder by opening and closing the valve;
A sensor for determining whether or not the accumulator pressure sensor is abnormal based on the accumulator pressure detected when the hydraulic pressure control valve is opened so that the accumulator pressure is lower than the lower limit value of the predetermined pressure range. An abnormality determination means;
A brake control device comprising: Current differential pressure indicating the relationship between the differential pressure between the accumulator pressure and the wheel cylinder pressure, which is the hydraulic pressure of the wheel cylinder, and the current value to be supplied to the hydraulic pressure control valve in order to open the hydraulic pressure control valve A storage unit for storing characteristics;
The sensor abnormality determining means determines a current value to be supplied to the hydraulic pressure control valve in order to make the accumulator pressure lower than the lower limit value of the predetermined pressure range with reference to the stored current differential pressure characteristic. The brake control according to claim 1, wherein it is determined whether or not the accumulator pressure sensor is abnormal based on an accumulator pressure detected when a current having the determined current value is supplied from the battery. apparatus.   The sensor abnormality determination means detects an accumulator pressure within the predetermined pressure range when the hydraulic pressure control valve is opened so that the accumulator pressure is lower than a lower limit value of the predetermined pressure range. The brake control device according to claim 1, wherein the accumulator pressure sensor is determined to be abnormal. A control valve abnormality determining means for determining whether or not the hydraulic pressure control valve is abnormal based on an operating state of the hydraulic pressure control valve when a current for opening the valve is supplied;
The sensor abnormality determining means detects an accumulator pressure within the predetermined pressure range when the hydraulic pressure control valve is opened so that the accumulator pressure is lower than a lower limit value of the predetermined pressure range. The brake control device according to claim 3, wherein when the hydraulic pressure control valve is determined to be normal, it is determined that the accumulator pressure sensor is abnormal. Relay abnormality determination that determines whether or not the relay is abnormal based on a response of the relay when a control current for turning on the operation of the motor is given to a relay that switches on / off of the operation of the motor that drives the pump Further comprising means,
The relay abnormality determination means determines whether the relay is abnormal when the accumulator pressure is lower than a lower limit value of the predetermined pressure range so that the sensor abnormality determination means determines an abnormality of the accumulator pressure sensor. The brake control device according to any one of claims 1 to 4, wherein

Images