JP2012020651A - Solenoid valve driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable continuation of brake control in accordance with a leakage amount during a leakage fault.SOLUTION: It is determined that such abnormal state is caused that a leakage amount of each of various solenoid valves is detected, the leakage amount is less than an operation current, and that the leakage amount is equal to an operation maintenance current or more. The abnormal state is a state in which even during a leakage fault, the solenoid valve can be returned to a state in which the leakage fault is not caused by stopping energizing to the solenoid of the solenoid valve. Therefore, when it is determined that the state is an abnormal one, by turning off a semiconductor switching element 82 being a generalization switching element, after turning off of energizing to the solenoid, by turning on the semiconductor switching element 82 after lapse of the prescribed time, if on-off driving of individual switching elements by brake control is permitted, EBD control can be continued in accordance with leakage amount.

Description

  The present invention relates to an electromagnetic valve driving device for driving an electromagnetic valve that controls the flow of fluid in a pipe line.

  Conventionally, brake control in a vehicle has been performed by driving a solenoid valve or a pump driving motor provided in an actuator for brake fluid pressure control. In such a brake fluid pressure control actuator used for brake control, a leak failure may occur in which a leak current flows through a solenoid (solenoid coil) for driving an electromagnetic valve. The leakage current is generated by a leakage of a semiconductor switching element for controlling on / off of the current to the solenoid, a short circuit of wiring, or the like. Such a leak current can be detected by, for example, a load driving circuit capable of leak detection / determination in Patent Document 1.

  When such a leak failure occurs, there is a possibility that appropriate brake control cannot be performed. For this reason, for example, a warning lamp indicating that the device that performs the brake control has failed is turned on, and the electromagnetic valve drive is prohibited, thereby prohibiting the brake control and returning to the normal brake (normal brake).

Japanese Patent Laid-Open No. 9-24815

  However, depending on the level of the leak failure, that is, the magnitude of the leak current, there is a case where it is not required to prohibit the brake control. In such a case, it is preferable that executable brake control can be performed rather than prohibiting electromagnetic valve driving and performing brake control. For example, when the brake control is prohibited, it is necessary to apply a wheel cylinder pressure (hereinafter referred to as pump pressurization) based on the discharge action of the brake fluid pressure by the pump (hereinafter referred to as pump pressurization) or EBD (Electronic Brake). Although it is impossible to execute brake control such as force distribution control (electronic braking force distribution control), it is desirable to execute these controls as much as possible.

  The present invention has been made in view of the above points, and an object of the present invention is to enable brake control to be continued in accordance with the amount of leakage at the time of a leakage failure.

  In order to achieve the above object, according to the first aspect of the present invention, direct current is applied to a plurality of solenoids for driving the plurality of solenoid valves (16 to 18, 21, 22, 36 to 38, 41, 42). A common overall switching element (82) that collectively controls on / off of energization from the power source (+ B) is provided, and is provided for each of the plurality of solenoids, and is individually switched to control on / off of energization for each of the plurality of solenoids. In the electromagnetic valve drive device comprising the element (83), the leakage amount, which is the magnitude of the leakage current of each of the plurality of solenoids, is less than the operating current required to move the valve bodies of the plurality of solenoid valves. And a determination means (1) for determining an abnormal state that is equal to or higher than an operation maintaining current capable of maintaining the position of each of the plurality of solenoid valves. 0, 160, 240, 250), and when it is determined by the determining means that the abnormal state is present, by turning off the general switching element, the energization to each of the solenoids of the plurality of solenoid valves is turned off. Control means (110, 120, 170, 180, 210, 220, 260, 270) for permitting on / off driving of the individual switching elements by brake control by turning on the general switching elements again after a predetermined time has elapsed. It is a feature.

  As described above, the leakage amount of the solenoid is detected, and it is determined that an abnormal state in which the leakage amount is less than the operating current and equal to or more than the operation maintaining current has occurred. In such an abnormal state, once energization of the solenoid of the solenoid valve is stopped for a predetermined time, the open / close state of the solenoid valve returns to a state where no leak failure has occurred. If it is determined that the state is abnormal, the overall switching element is turned off to turn off the energization of the solenoids of each of the solenoid valves, and the overall switching element is turned on again after a predetermined time. Thus, after returning the open / close state of the solenoid valve to a state where no leak failure has occurred, brake control is permitted by turning on / off individual switching elements corresponding to solenoids other than the solenoid determined to be in the abnormal state. Thus, even if a leak failure occurs, if the amount of leak satisfies the above abnormal condition, the brake control can be continued without prohibiting all the brake controls.

  For example, as a solenoid valve, a differential pressure for controlling a shutoff state and a differential pressure state of pipes (A, E) connecting between a master cylinder (13) and a plurality of wheel cylinders (14, 15, 34, 35). A control valve (16, 36), a pressure-increasing control valve (17, 18, 37, 38) that is provided corresponding to each of the plurality of wheel cylinders and controls the pressure increase in each of the plurality of wheel cylinders; There is known a hydraulic brake device that is provided corresponding to each of the wheel cylinders and includes pressure reduction control valves (21, 22, 41, 42) that control the pressure reduction of each of the plurality of wheel cylinders. . In such a hydraulic brake device, it is conceivable to perform EBD control by turning on and off the pressure increase control valve. However, in the EBD control, the differential pressure control valve is open and the pressure reduction control valve is closed. There is no need to turn these differential pressure control valves and pressure reduction control valves on and off.

  Therefore, in the invention according to claim 2, the control means corresponds to an electromagnetic valve other than the pressure increase control valve for the rear wheels (RL, RR), wherein the solenoid determined to be in an abnormal state by the determination means. If it is, the EBD control by turning on and off the pressure increase control valve is permitted as the brake control.

  In this way, it is permitted to perform EBD control based on which solenoid valve is leaking, that is, whether the solenoid valve is other than the rear wheel pressure increase control valve, and the amount of leak, You can decide whether to ban. As a result, EBD control is not prohibited in all cases where a leak failure occurs, but EBD control can be continued according to the amount of leakage, and EBD control is continued according to which solenoid valve has the leak failure. It is also possible to do.

  In addition, as a solenoid valve, a differential pressure control valve for controlling a shutoff state and a differential pressure state of a pipe line connecting between the master cylinder and the plurality of wheel cylinders, and a plurality of wheel cylinders are provided, A pressure increase control valve for controlling the pressure increase of each of the plurality of wheel cylinders, a pressure reduction control valve for controlling the pressure reduction of each of the plurality of wheel cylinders, and a difference among the pipelines 2. Description of the Related Art There is known a hydraulic brake device that includes a pump that discharges brake fluid to the wheel cylinder side of a pressure control valve and a motor that drives the pump.

  In such a hydraulic brake device, the motor (60) is energized while the differential pressure control valve is in the differential pressure state, and the brake fluid is discharged by the pump (19, 39), so that the wheel is used as brake control. Although it is conceivable to execute a slope start assist control in which the cylinder is pumped to assist starting when the vehicle is stopped, the pressure increase control valve is open and the pressure reduction control valve is closed in this slope start assist control. There is no need to turn on and off these pressure increase control valve and pressure reduction control valve.

  Therefore, in the invention according to claim 3, the control means applies a brake when the solenoid determined to be in an abnormal state by the determination means corresponds to an electromagnetic valve other than the differential pressure control valve. Slope start assist control is permitted as control.

  As described above, it is possible to determine whether to permit or prohibit the slope start assist control based on the leak amount. Thus, it is possible to continue the slope start assist control according to the amount of leak, instead of prohibiting the slope start assist control in all cases where a leak failure occurs.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

It is the figure which showed the whole structure of the brake control system 1 for vehicles containing the various solenoid valves driven by the solenoid valve drive device concerning 1st Embodiment of this invention. It is the circuit diagram which showed an example of the drive circuit of various solenoid valves 16-18, 21, 22, 36-38, 41, 42 and the motor 60. It is the figure which showed the magnitude | size of the electric current sent through the solenoid of a solenoid valve, and the operating state of a solenoid valve. 3 is a flowchart of EBD control executed by a brake ECU 70 of the brake control system 1. It is a flowchart of the slope start assistance control which brake ECU70 performs.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
A first embodiment of the present invention will be described. FIG. 1 shows an overall configuration of a vehicle brake control system 1 including various solenoid valves driven by a solenoid valve driving apparatus according to a first embodiment of the present invention. The brake control system 1 performs brake control such as slope start assist control and failure control. Hereinafter, the configuration of the brake control system 1 will be described with reference to FIG.

  As shown in FIG. 1, the brake control system 1 is configured by a hydraulic brake device in which a hydraulic circuit is configured. In FIG. 1, when the driver depresses the brake pedal 11, the pedaling force is boosted by the booster 12, and the master pistons 13a and 13b disposed in the M / C 13 are pressed. As a result, the same M / C pressure is generated in the primary chamber 13c and the secondary chamber 13d defined by the master pistons 13a and 13b. The M / C pressure is transmitted to each of the W / Cs 14, 15, 34, and 35 through the brake fluid pressure control actuator 50. The M / C 13 is provided with a master reservoir 13e having passages communicating with the primary chamber 13c and the secondary chamber 13d so that the amount of brake fluid in the system is always appropriate.

  The brake fluid pressure control actuator 50 has a first piping system 50a and a second piping system 50b. The first piping system 50a controls the brake fluid pressure applied to the left front wheel FL and the right rear wheel RR, and the second piping system 50b controls the brake fluid pressure applied to the right front wheel FR and the left rear wheel RL.

  Since the 1st piping system 50a and the 2nd piping system 50b are the same structures, below, the 1st piping system 50a is explained and explanation is omitted about the 2nd piping system 50b.

  The first piping system 50a transmits the M / C pressure described above to the W / C 14 provided on the left front wheel FL and the W / C 15 provided on the right rear wheel RR, and generates a W / C pressure. A pipe A is provided.

  Further, the pipeline A includes a first differential pressure control valve 16 configured by a normally-open electromagnetic valve that can be controlled to a communication state and a differential pressure state. The valve position of the first differential pressure control valve 16 is adjusted so that the first differential pressure control valve 16 is in a communicating state during normal braking (when vehicle motion control is not executed) when the driver operates the brake pedal 11. When a current is passed through the solenoid provided in the one differential pressure control valve 16, the valve position is adjusted so that the larger the current value, the larger the differential pressure state.

  When the first differential pressure control valve 16 is in the differential pressure state, only when the brake fluid pressure on the W / C 14, 15 side is higher than the M / C pressure by a predetermined level or more, the M / The brake fluid is allowed to flow only to the C13 side. For this reason, the W / C 14, 15 side is always maintained so as not to be higher than the predetermined pressure by the M / C 13 side.

  The pipeline A branches into two pipelines A1 and A2 on the W / C 14 and 15 side downstream of the first differential pressure control valve 16. The pipeline A1 is provided with a first pressure increase control valve 17 that controls the increase of the brake fluid pressure to the W / C 14, and the pipeline A2 is a first pressure that controls the increase of the brake fluid pressure to the W / C 15. A two pressure increase control valve 18 is provided.

  The first and second pressure increase control valves 17 and 18 are constituted by two-position solenoid valves that can control the communication / blocking state. The first and second pressure increase control valves 17 and 18 are in a communicating state when the control current to the solenoids provided in the first and second pressure increase control valves 17 and 18 is zero (when no power is supplied). When the control current is supplied to the solenoid (when energized), the solenoid is normally open.

  In the pipeline A, the first and second pressure increase control valves 17 and 18 and the pipeline B serving as a pressure-reducing pipeline connecting the pressure regulating reservoir 20 between the W / Cs 14 and 15 are controlled in communication / blocking states. The 1st pressure reduction control valve 21 and the 2nd pressure reduction control valve 22 which are comprised by the 2 position solenoid valve which can be each arrange | positioned. The first and second pressure reducing control valves 21 and 22 are normally closed.

  A conduit C serving as a reflux conduit is disposed between the pressure regulating reservoir 20 and a conduit A serving as a main conduit. The pipe C is provided with a self-priming pump 19 driven by a motor 60 that sucks and discharges brake fluid from the pressure regulating reservoir 20 toward the M / C 13 side or the W / C 14, 15 side. The motor 60 is driven by controlling energization to a motor relay (not shown).

  A conduit D serving as an auxiliary conduit is provided between the pressure regulating reservoir 20 and the M / C 13. Brake fluid is sucked from the M / C 13 by the pump 19 through the pipeline D and discharged to the pipeline A, so that the brake fluid is supplied to the W / C 14 and 15 side at the time of brake control. Pressurize the wheel W / C pressure. In addition, although the 1st piping system 50a was demonstrated here, the 2nd piping system 50b is also the same structure, The 2nd piping system 50b is also provided with the structure similar to each structure with which the 1st piping system 50a was equipped. Yes. Specifically, the second differential pressure control valve 36 corresponding to the first differential pressure control valve 16, the third and fourth pressure increase control valves 37, 38 corresponding to the first and second pressure increase control valves 17, 18. Corresponding to the third and fourth decompression control valves 41 and 42 corresponding to the first and second decompression control valves 21 and 22, the pump 39 corresponding to the pump 19, the reservoir 40 corresponding to the reservoir 20, and the pipelines A to D There are pipelines EH to do.

  The brake ECU 70 is responsible for the control system of the brake control system 1 and is constituted by a well-known microcomputer having a CPU, a ROM, a RAM, an I / O, and the like, and performs various calculations according to a program stored in the ROM. Execute the process. The brake ECU 70 drives the various solenoid valves 16-18, 21, 22, 36-38, 41, 42 and the motor 60, and performs brake control such as slope start assist control and EBD control when a predetermined condition is satisfied. Yes.

  FIG. 2 is a circuit diagram showing an example of a drive circuit for the various solenoid valves 16 to 18, 21, 22, 36 to 38, 41, 42 and the motor 60. In addition, about the various solenoid valves 16-18, 21, 22, 36-38, 41, 42, the solenoid for a solenoid valve drive is shown in figure.

  As shown in this figure, the motor 60 and the various solenoid valves 16-18, 21, 22, 36-38, 41, 42 are driven based on the voltage + B (for example, 12V) of the DC power source, and the brake ECU 70, for example, The semiconductor switching elements 80 to 83 made of MOSFET are controlled by being turned on / off.

  Semiconductor switching elements 80 and 81 are provided on the high side and the low side of the motor 60, respectively. The high-side semiconductor switching element 80 is basically turned on after the ignition switch is turned on. For this reason, on / off of current supply to the motor 60 is controlled by turning on / off the semiconductor switching element 81 on the low side.

  On the high side of the various solenoid valves 16 to 18, 21, 22, 36 to 38, 41, 42, a general semiconductor switching element (general switching element) 82 is provided, which is more than the semiconductor switching element 82. Various solenoid valves 16-18, 21, 22, 36-38, 41, 42 are connected in parallel on the low side. That is, the semiconductor switching element 82 is provided in a shared portion shared by all the solenoids in the power supply line from the DC power supply to the plurality of solenoids. For the first and second differential pressure control valves 16 and 36, shunt resistors 16a and 36a are connected in series to the solenoid, and the current value flowing through the solenoid is monitored by the shunt resistors 16a and 36a. The differential pressure value generated by the first and second differential pressure control valves 16 and 36 can be monitored.

  In addition, a semiconductor switching element 83 is provided in each of the current supply lines to the various solenoid valves 16 to 18, 21, 22, 36 to 38, 41, and 42 connected in parallel. That is, the semiconductor switching element 83 is provided in an occupied portion that is individually occupied by each solenoid in the power supply line from the DC power supply to the plurality of solenoids. The high-side semiconductor switching element 82 is also basically turned on after the ignition switch is turned on, and various semiconductor valves 16 to 18, 21 are turned on and off by turning on and off the semiconductor switching element 83 provided in each current supply line. , 22, 36 to 38, 41, and 42 are supplied with current.

  In FIG. 2, only the shunt resistors 16 a and 36 a that can monitor the current flowing through the solenoids of the first and second differential pressure control valves 16 and 36 are illustrated, but the pressure increase control valves 17, 18, 37, Means for monitoring the current flowing through the 38 solenoids and the solenoids of the pressure-reducing control valves 21, 22, 41, 42 are also provided. For example, the current flowing therethrough may be monitored by detecting the voltage across the solenoids of the pressure-increasing control valves 17, 18, 37, 38 and the solenoids of the pressure-reducing control valves 21, 22, 41, 42, A current may be monitored by connecting a shunt resistor in series with each solenoid.

  Each of the semiconductor switching elements 80 to 83 is provided with freewheeling diodes 80a to 83a so that a freewheeling current can flow when the semiconductor switching elements 80 to 83 are switched from on to off. A reflux diode 90 is also connected between the solenoids of the first and second differential pressure control valves 16 and 36 and the pressure increase control valves 17, 18, 37, and 38. By allowing the reflux current to flow, it is possible to suppress the operating noise that is generated by abrupt on / off. However, a reflux diode is not connected to the solenoid of each pressure reducing control valve 21, 22, 41, 42. This is because at the time of depressurization such as ABS control, it is desired to increase the ON / OFF switching speed of each depressurization control valve 21, 22, 41, 42 in preference to the suppression of the operating noise. Thereby, each decompression control valve 21, 22, 41, 42 can be driven on / off earlier.

  As described above, the brake control system 1 according to the present embodiment is configured. Next, a case where EBD control is executed will be described as an example of brake control executed by the brake ECU 70 of such a brake control system 1. Note that the EBD control start conditions and the specific setting method of the front / rear braking force distribution are the same as in the prior art, and the manner of execution of each control when a leak failure occurs is a different part from the prior art. Here, only different portions from the conventional one will be described.

  In the EBD control, control is performed to optimally distribute the braking force of the front and rear wheels according to the driving situation. In this EBD control, if the rear wheel is locked before the front wheel, it becomes unstable. Therefore, by maintaining the braking force of the rear wheel, the W / C pressure of the rear wheel is not increased and the rear wheel leading lock is achieved. Control to prevent this. Therefore, when the EBD control start condition is satisfied, energization of the solenoids of the second and fourth pressure-increasing control valves 18 and 38 corresponding to the rear wheels RL and RR is turned on, and these are turned off.

  When performing such EBD control, EBD control cannot be performed if the second and fourth pressure increase control valves 18 and 38 have a leak failure, but the other solenoid valves 16, 17, 21, 22, When 36, 37, 41, and 42 have a leak failure, the EBD control can be executed depending on the degree of the leak failure. That is, when the second and fourth pressure increase control valves 18 and 38 have a leak failure, the communication state and the cutoff state of the second and fourth pressure increase control valves 18 and 38 cannot be appropriately switched. It becomes impossible to control. On the other hand, when the electromagnetic valves 16, 17, 21, 22, 36, 37, 41, 42 other than these have a leak failure, the electromagnetic valves are selected according to the amount of leakage (leakage current). It is determined whether or not the valve positions 16, 17, 21, 22, 36, 37, 41, and 42 can be returned to a state where no leak failure has occurred. And if it can return to the state where the leak failure has not occurred, the EBD control may be executed.

  Here, the relationship between the amount of leakage and whether or not it can be restored to a state where no leakage failure has occurred will be described. FIG. 3 is a diagram showing the magnitude of current flowing through the solenoid of the solenoid valve and the operating state of the solenoid valve.

  As shown in FIG. 3, when the solenoid valve is driven, an operating current, that is, a current larger than the current required to move the valve body included in the solenoid valve is supplied to the solenoid. To drive the solenoid valve.

  However, when the solenoid valve is driven, in order to maintain the state where the solenoid valve is being driven, it is only necessary to keep an operation maintaining current smaller than the operation current flowing. This is because the solenoid valve has magnetic hysteresis, and the relationship between the position of the solenoid valve valve body and the current flowing through the solenoid draws a hysteresis loop, which is necessary to move the valve body position from the non-energized state. Compared to a large current (which corresponds to the operating current), the current required to hold the valve body in the same position after moving the valve body (this corresponds to the operation maintaining current) is small.

  For this reason, if the amount of leakage is less than the operating current, once the energization to the solenoid of the solenoid valve is stopped, even if the leakage current flows again, only a current that is less than the operating current will flow. The valve body does not move, and the electromagnetic valve can be returned to a state where no leakage failure has occurred. Once the energization of the solenoid of the solenoid valve is stopped, the high-side semiconductor switching element 82 can be turned off. Thus, when a leak failure occurs, if the amount of leak is less than the operating current, the solenoid valve can be returned to a state where no leak failure has occurred by turning off the solenoid valve for a predetermined time. It is possible to return to a state where EBD control can be performed.

  However, since the noise is included in the both-end voltage of the solenoid or the both-end voltage of the shunt resistor used for detecting the leakage amount, there is a possibility that the leakage current is recognized to some extent even if no leakage current flows. In addition, even if it is a leakage current, if the amount of leakage is less than the operating holding current, the solenoid valve will naturally return to a state where no leakage failure has occurred, so the solenoid valve is actively turned off for a predetermined time. There is no need to perform any action. Therefore, it is detected that an abnormal state in which the amount of leakage is less than the operating current and greater than or equal to the operation maintaining current has occurred, and in such an abnormal state, power supply to the solenoid is temporarily stopped. Thus, it is possible to return the solenoid valve to a state where no leak failure has occurred. Then, by turning on the semiconductor switching element 82 again after a predetermined time has elapsed to permit the on / off drive of each semiconductor switching element 83 by brake control, the brake control can be continued according to the leak amount.

  Based on such knowledge, the following control is performed. FIG. 4 is a flowchart of EBD control executed by the brake ECU 70 of the brake control system 1 according to the present embodiment. The processing shown in this figure is executed at predetermined control cycles when the ignition switch is on.

  First, in step 100, it is determined whether a leak is occurring. Specifically, the leakage amounts of the various solenoid valves 16 to 18, 21, 22, 36 to 38, 41, and 42 are detected, and whether or not the leakage amounts are assumed to be a leakage current. Judging. Here, if a negative determination is made, it is not necessary to execute control corresponding to the leak failure, so the routine proceeds to step 110, where it is determined whether or not there is a request for EBD control. The EBD control is started to proceed, and if there is no request, the processing is terminated as it is. The EBD control request is issued when an EBD control start condition (for example, when the rear wheel slip rate exceeds a predetermined threshold) is satisfied. In this case, the second and second wheels corresponding to the rear wheels RL and RR are used. By energizing the solenoids of the four pressure-increasing control valves 18 and 38 to turn them off, the rear wheel leading lock can be prevented by maintaining the braking force of the rear wheels RL and RR.

  On the other hand, if an affirmative determination is made in step 100, the process proceeds to step 130, in which whether or not the electromagnetic valve that is leaking corresponds to the rear wheels RL and RR, and whether or not it is a pressure increase control valve, That is, it is determined whether or not the second and fourth pressure increase control valves 18 and 38 are present. That is, when the second and fourth pressure increase control valves 18 and 38 used for maintaining the W / C pressure of the rear wheels RL and RR have a leak failure, the EBD control cannot be performed. Even if the valve has a leak failure, it may be possible to perform EBD control. For this reason, the solenoid valve in which the leakage has failed is specified, and if it is the second or fourth pressure increase control valve 18, 38, the process proceeds to step 140. Then, all control of EBD control is prohibited, and a warning lamp (WL) (not shown) is lit to notify the user that EBD control cannot be performed.

  Further, when a negative determination is made at step 130, the routine proceeds to step 150, where it is determined whether or not the leak amount is equal to or greater than the operating current. If an affirmative determination is made here, even if the valve is temporarily returned to the position before the leakage failure, when the energization to the solenoid of the semiconductor switching element 82 is turned on again, a leakage current exceeding the operating current is generated in the solenoid valve. This will cause a leak failure. In such a case, EBD control cannot be performed even if the solenoid valve in which the leak failure has occurred is other than the second and fourth pressure increase control valves 18 and 38. Therefore, if an affirmative determination is made here, the process of step 140 is performed, and if a negative determination is made, the process proceeds to step 160.

  In step 160, it is determined whether or not the leakage amount is less than the operation maintaining current. If an affirmative determination is made here, it is not leak current but noise, or even if it is leak current, the state of the solenoid valve can return to a state where no leak failure has occurred naturally. Since it is a leakage current, the process proceeds to step 110 and the same operation as described above is performed. If a negative determination is made here, once the energization of the solenoid of the solenoid valve is stopped, even if a leakage current flows again, only a current that is less than the operating current and about the operation maintaining current flows. Does not move, and the solenoid valve can be returned to a state where no leakage failure has occurred.

  Therefore, it is determined in step 170 whether there is any experience of switching the semiconductor switching element 82 from off to on. If not, the process proceeds to step 180, where the semiconductor switching element 82 is turned off for a predetermined time and then turned on. By performing such processing, the solenoid valve can be returned to a state where no leak failure has occurred. Even if a leakage current flows by turning on the semiconductor switching element 82 again, only a current of an operation maintaining current that is less than the operating current flows, so that the valve body does not move, and a leakage failure occurs in the electromagnetic valve. It can maintain the state that has been returned to the state that is not.

  At this time, the time for turning off the semiconductor switching element 82 is set to be longer than the time necessary for returning the valve position of the solenoid valve to the state when the leakage current is not flowing. For this reason, when the semiconductor switching element 82 is turned off, the valve position of the electromagnetic valve can be reliably returned to the state when no leakage current is flowing. In step 170, it is determined whether or not the semiconductor switching element 82 has been switched from OFF to ON. If there is, it is already completed to return the solenoid valve to the state before the leakage current flows. Therefore, the process of step 180 is not performed again.

  As a result, it is possible to return to a state in which the EBD control can be executed. Thereafter, the process proceeds to step 110, and the same processing as described above is performed based on whether or not there is an EBD control request.

  As described above, in the present embodiment, the leak amount of the various solenoid valves 16-18, 21, 22, 36-38, 41, 42 is detected, and the leak amount is less than the operating current and greater than or equal to the operation maintaining current. It is determined that a certain abnormal state has occurred. Such an abnormal state is a state in which, even in a leak failure, the solenoid valve can be returned to a state where no leak failure has occurred by once stopping energization of the solenoid of the solenoid valve. For this reason, when it is determined that the state is abnormal, the semiconductor switching element 82 is turned off to turn off the energization to the solenoid, and then the semiconductor switching element 82 is turned on again after a predetermined time has elapsed. If the on / off drive of the individual switching element is permitted, it becomes possible to continue the EBD control according to the leak amount.

  Further, in the present embodiment, it is determined which solenoid valve has a leak failure and whether to permit or prohibit the EBD control based on the leak amount. As a result, EBD control is not prohibited in all cases where a leak failure occurs, but EBD control can be continued according to the amount of leakage, and EBD control is continued according to which solenoid valve has the leak failure. It is also possible to do.

(Second Embodiment)
A second embodiment of the present invention will be described. In the present embodiment, a description will be given of a case where the slope start assist control is performed according to the leak amount when the brake control system 1 shown in the first embodiment executes the slope start assist control instead of the EBD control. Note that the specific control method in the slope start assist control is the same as the conventional method, and the method of executing the slope start assist control when a leak failure occurs is different from the conventional method. Only the different parts will be described.

  FIG. 5 is a flowchart of slope start assist control executed by the brake ECU 70 of the brake control system 1 according to the present embodiment. The processing shown in this figure is executed at predetermined control cycles when the ignition switch is on.

  First, in step 200, it is determined whether or not a leak is occurring by the same method as in step 100 of FIG. Here, if a negative determination is made, there is no need to execute control corresponding to the leak failure, so the routine proceeds to step 210, where it is determined whether there is a request for slope start assist control. Proceeding to 220, the slope start assist control is started, and if there is no request, the processing is terminated as it is. The request for the slope start assist control is issued when the start condition of the slope start assist control (for example, when stopping on an uphill) is satisfied. In that case, the first and second differential pressure control valves 16 and 36 are brought into a differential pressure state, and the motor 60 is driven to perform pump pressurization, whereby the W / C pressure of each wheel FL to RR is increased. Even if the user pressurizes and loosens the brake pedal 11, it is possible to start the vehicle well so that the vehicle from the slope does not slide down.

  On the other hand, if an affirmative determination is made in step 200, the process proceeds to step 230, where it is determined whether or not the leaking solenoid valve is the first and second differential pressure control valves 16 and 36. That is, when the first and second differential pressure control valves 16 and 36 have a leak failure, the slope start assist control by pump pressurization cannot be performed, but even if the other solenoid valves have a leak failure, the slope It may be possible to perform start assist control. For this reason, the solenoid valve in which the leak failure has occurred is specified, and if it is the first and second differential pressure control valves 16 and 36, the process proceeds to step 240. Then, all control of the slope start assist control is prohibited, and a warning lamp (WL) (not shown) is turned on to notify the user that the slope start assist control cannot be performed.

  On the other hand, if a negative determination is made in step 230, the process proceeds to step 250, and it is determined whether or not the leakage amount is equal to or greater than the operating current, as in step 150 of FIG. If an affirmative determination is made here, even if the valve position is once returned to the state before the leakage failure, when the energization to the solenoid of the semiconductor switching element 82 is turned on again, a leakage current exceeding the operating current is generated in the solenoid valve. This will cause a leak failure. In such a case, slope start assistance control cannot be performed. Therefore, the process proceeds to step 240 to prohibit all control of the slope start assist control and to turn on a warning lamp (WL) (not shown) to inform the user that the slope start assist control cannot be performed.

  Further, when a negative determination is made in step 250, the process proceeds to step 260, and it is determined whether or not the leak amount is less than the operation maintaining current, similarly to step 160 of FIG. If an affirmative determination is made here, it is not leak current but noise, or even if it is leak current, the state of the solenoid valve can return to a state where no leak failure has occurred naturally. Since it is a leakage current, the process proceeds to step 210 to perform the same operation as described above. If a negative determination is made here, once the energization of the solenoid of the solenoid valve is stopped, even if a leakage current flows again, only a current that is less than the operating current and about the operation maintaining current flows. Does not move, and the solenoid valve can be returned to a state where no leakage failure has occurred.

  Therefore, in step 270, as in step 170 of FIG. 4, it is determined whether there is any experience of switching the semiconductor switching element 82 from off to on. If not, the process proceeds to step 280, and as in step 180 of FIG. The semiconductor switching element 82 is turned off after being turned off for a predetermined time. By performing such processing, the solenoid valve can be returned to a state where no leak failure has occurred. Even if a leakage current flows by turning on the semiconductor switching element 82 again, only a current of an operation maintaining current that is less than the operating current flows, so that the valve body does not move, and a leakage failure occurs in the electromagnetic valve. It can maintain the state that has been returned to the state that is not.

  As a result, it is possible to return to the state in which the slope start assist control can be executed, and thereafter, the process proceeds to step 210, and the same processing as described above is performed based on whether there is a slope start assist control request.

  As described above, also in the present embodiment, the leak amount of the various solenoid valves 16-18, 21, 22, 36-38, 41, 42 is detected, and the slope start assist control is performed based on the leak amount. Decide whether to allow or prohibit. If the leakage amount is less than the operating current and greater than or equal to the operation maintaining current, the solenoid valve is temporarily turned off so that the solenoid valve does not have a leak failure. I try to return it. As a result, it is possible not to prohibit slope start assist control in all cases where a leak failure occurs, but to continue slope start assist control, which is a form of brake control that performs pump pressurization according to the amount of leak. Become.

(Other embodiments)
In the said embodiment, the various solenoid valves 16-18, 21, 22, 36-38, 41, 42 The semiconductor switching element 82 which performs on-off of all the solenoids collectively is made into various solenoid valves 16-18, 21, 22. , 36 to 38, 41, 42 are provided on the high side. However, this is merely an example, and the semiconductor switching element 82 may be disposed on the low side of the various solenoid valves 16-18, 21, 22, 36-38, 41, 42.

  The steps shown in each figure correspond to means for executing various processes. That is, the part that executes the processing of steps 150, 160, 230, and 250 in FIG. 3 and FIG. 4 is the determination means, and the part that executes the processing of steps 110, 120, 170, 180, 210, 220, 260, and 270 controls. It corresponds to the means.

  DESCRIPTION OF SYMBOLS 1 ... Brake control system 16, 36 ... 1st, 2nd differential pressure control valve, 17, 18, 37, 38 ... 1st-4th pressure increase control valve, 21, 22, 41, 42 ... 1st-1st 4 decompression control valve, 60 ... motor, 70 ... brake ECU, 82 ... semiconductor switching element (overall switching element), 83 ... semiconductor switching element (individual switching element)

Claims (3)

Electromagnetic valve driving device for driving a plurality of electromagnetic valves (16-18, 21, 22, 36-38, 41, 42) provided in a hydraulic circuit of a hydraulic brake device and driven by passing a current through the solenoid In
A DC power source (+ B) for energizing the solenoids of the plurality of solenoid valves;
A common overall switching element (82) for collectively switching on and off the energization from the DC power supply to the solenoids of the plurality of solenoid valves;
An individual switching element (83) that is provided for each solenoid of the plurality of solenoid valves and switches on / off of energization to each of the plurality of solenoids;
For each of the plurality of solenoids, a leakage amount that is a magnitude of a leakage current flowing through the solenoid is less than an operating current required to move the valve body of the solenoid valve corresponding to the solenoid, and Determination means (150, 160, 230, 250) for determining an abnormal state that is equal to or higher than an operation maintaining current capable of maintaining the position of the valve body of the solenoid valve corresponding to the solenoid;
When it is determined by the determination means that any of the plurality of solenoids is in the abnormal state, the general switching element is turned off to turn off the energization of the plurality of solenoids, and the generalization is performed after a predetermined time has elapsed. Control means (110, 120, 170) for permitting brake control by turning on / off the individual switching elements corresponding to solenoids other than the solenoids determined to be in the abnormal state by the determination means after the switching elements are turned on again. 180, 210, 220, 260, 270). In the hydraulic circuit, as the electromagnetic valve, a shut-off state and a differential pressure state of pipelines (A, E) connecting the master cylinder (13) and the plurality of wheel cylinders (14, 15, 34, 35). A normally open type differential pressure control valve (16, 36) for controlling the pressure control valve, and a pressure increase control valve (17, 36) provided corresponding to each of the plurality of wheel cylinders to control the pressure increase of each of the plurality of wheel cylinders 18, 37, 38) and normally closed pressure reducing control valves (21, 22, 41, 42) provided corresponding to the plurality of wheel cylinders and controlling the pressure reduction of the wheel cylinders, respectively. Have
In the case where the solenoid that is determined to be in the abnormal state by the determination unit corresponds to an electromagnetic valve other than the pressure increase control valve of a rear wheel (RL, RR), The electromagnetic valve driving device according to claim 1, wherein electronic braking force distribution control by turning on and off the pressure increase control valve is permitted as the brake control. In the hydraulic circuit, as the electromagnetic valve, a shut-off state and a differential pressure state of pipelines (A, E) connecting the master cylinder (13) and the plurality of wheel cylinders (14, 15, 34, 35). A differential pressure control valve (16, 36) for controlling the pressure and a normally open pressure increase control valve (17, 36) provided for each of the plurality of wheel cylinders and controlling the pressure increase of each of the plurality of wheel cylinders. 18, 37, 38), and normally closed pressure reducing control valves (21, 22, 41, 42) provided corresponding to the plurality of wheel cylinders and controlling the pressure reduction of the wheel cylinders, A pump (19, 39) that discharges brake fluid to the wheel cylinder side of the differential pressure control valve in the pipe; and a motor (60) that drives the pump. Pressure Said By performing power supply to the motor and the ejection operation of the brake fluid by the pump while, can perform the wheel cylinder pressure pump pressurizing performing start assisting when the vehicle is stopped hill start assist control as the brake control,
If the solenoid determined to be in the abnormal state by the determination means corresponds to an electromagnetic valve other than the differential pressure control valve, the control means assists the slope start as the brake control. 3. The electromagnetic valve driving device according to claim 1, wherein control is permitted.

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