JP2007112158A - Vehicle control device - Google Patents

Abstract

Comfort is improved in a vehicle including a braking system including a hydraulic pressure control drive system.
In a vehicle, an ECU 100 can execute vehicle speed maintenance control using a brake actuator 200. On the other hand, when the temperature of the brake actuator 200 has risen to such an extent that vehicle speed maintenance control can be difficult in the near future, a warning buzzer is output to the driver, and the temperature rise is notified. The output of the warning buzzer is controlled in warning processing executed by the ECU 100. In the warning process, the warning buzzer is output only when the temperature of the brake actuator 200 is the warning target temperature and the vehicle speed maintenance control execution condition is satisfied.
[Selection] Figure 3

Description

  The present invention relates to a technical field of a vehicle control device that controls a vehicle including a braking system including a hydraulic pressure control drive system such as a brake actuator.

  As this type of device, a device that maintains the vehicle speed below the target vehicle speed has been proposed (see, for example, Patent Document 1). According to the wheel vehicle disclosed in Patent Document 1 (hereinafter referred to as “conventional technology”), the electronic control unit increases the braking force according to the value at which the detected vehicle speed exceeds or falls below the threshold value, respectively. Alternatively, since the hydraulic braking control device is controlled so as to decrease, the detected vehicle speed can be maintained below a threshold value.

  Further, the temperature of a hydraulic control drive system such as a hydraulic braking control device rises during the operation process. Since the control for maintaining the vehicle speed described above operates the hydraulic pressure control drive system continuously for a relatively long time, there is a possibility of further promoting the temperature rise of the hydraulic pressure control drive system. Therefore, in this type of device equipped with a hydraulic control drive system, when the hydraulic control drive system becomes hot, a warning is given to the driver via a buzzer and the control for maintaining the vehicle speed. Is configured to be prohibited.

Japanese National Patent Publication No. 10-507145

  There are many other types of vehicle control using a braking system including a hydraulic pressure control drive system in addition to vehicle speed maintenance control. Among these, there are opportunities for operating the hydraulic pressure control drive system compared to vehicle speed maintenance control. There are few things. Such control is often operable even when the hydraulic control drive system is at a high temperature.

  However, as a driver's psychology, it is easy to make an erroneous determination that all control using the hydraulic pressure control drive system is prohibited in accordance with the warning described above. Continuing to drive the vehicle while leaving such a misjudgment will leave the occupant feeling unnecessary annoyance. That is, the conventional technology has a technical problem that passenger comfort may be impaired.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a vehicle control device capable of improving comfort in a vehicle including a braking system including a hydraulic pressure control drive system.

  In order to solve the above-described problems, a vehicle control device according to the present invention is a vehicle control device that controls a vehicle including a braking system including a hydraulic pressure control drive system for controlling the hydraulic pressure of braking fluid. And a control means for controlling the braking system so that a speed when the vehicle descends the slope is maintained below a predetermined value when a predetermined execution condition is satisfied, and the hydraulic pressure control drive system A specifying means for specifying the temperature of the apparatus, a determining means for determining whether or not the temperature is equal to or higher than a predetermined first reference temperature, and the execution condition is satisfied and the temperature is equal to or higher than the first reference temperature. Output means for outputting predetermined warning information when it is determined.

  The “braking system” in the present invention is capable of braking a vehicle by applying a braking force to each wheel to be braked, and is a brake that defines the braking force by the action of a hydraulic control drive system. This is a concept that encompasses a mechanism, apparatus, or system having a configuration that can control the hydraulic pressure of the liquid independently of a braking operation (for example, depression of a brake pedal) based on the driver's braking intention. The hydraulic pressure control drive system is a concept that encompasses a mechanism, a device, or a system that transmits hydraulic pressure and that is driven to variably control the hydraulic pressure by a control unit that will be described later, and is called, for example, a brake actuator. Take the form.

  The hydraulic pressure control drive system preferably corresponds to each wheel for the purpose of independently controlling the hydraulic pressure of the brake fluid corresponding to each wheel (hereinafter referred to as “braking pressure” as appropriate). The hydraulic pressure transmission path includes a pressure increasing path and a pressure reducing path, and each path includes an electromagnetic on-off valve (for example, a solenoid valve). In this case, the braking pressure corresponding to each wheel is appropriately controlled by controlling the driving mode such as the open / close state of the electromagnetic on-off valve and the output of a circulation means (for example, a pump) for supplying the brake fluid to the hydraulic pressure transmission path. Are controlled independently of each other.

  According to the vehicle control apparatus of the present invention, the braking system is preferably used so that the speed when the vehicle descends the slope (hereinafter referred to as “vehicle speed” as appropriate) is maintained below a predetermined value by the control means. The hydraulic pressure control drive system is controlled. Hereinafter, such control will be referred to as “vehicle speed maintenance control” as appropriate. Here, the “slope” is a concept that includes a road surface having a slope enough to start or continue a downhill when at least no braking force is applied to the wheels. In other words, it refers to a road surface that can maintain a non-zero vehicle speed by controlling the braking force applied to each wheel.

  The vehicle speed maintenance control is executed when a predetermined execution condition is satisfied by the control means. Here, the “predetermined execution condition” is a condition that is defined in advance so that the vehicle speed maintenance control is executed in advance. Typically, the execution of the vehicle speed maintenance control is performed from the viewpoint of reflecting the intention of the occupant. Indicates the presence or absence of input to prompt the user. Such an input may be generated in accordance with, for example, an operation button, an operation lever, or an operation dial operated by an occupant. Such an operation may be defined as a combination of a plurality of operations. For example, there is a shift position corresponding to a relatively large gear ratio (for example, “L” or “R” in an automatic transmission, etc.) when the operation button is operated by the occupant and the gear ratio of the transmission is selected. The position may be defined in advance so that an input is generated in the case of a position corresponding to (1). Or it may generate | occur | produce without operation of a passenger | crew etc. from a controller, another apparatus, etc., when some conditions defined as what should maintain a vehicle speed are satisfy | filled.

  The specifying means specifies the temperature of the hydraulic pressure control drive system. Here, the “specific” in the present invention is not only directly detected by, for example, physical, electrical, mechanical, mechanical, or chemical detection means, but also the detected result as an electrical signal. It is a concept that includes indirectly acquiring and further deriving from these detected or acquired values based on a predetermined algorithm or calculation formula. Therefore, the specifying means according to the present invention may be a detecting means such as a temperature sensor arranged at a predetermined location of the hydraulic pressure control drive system, or obtains the temperature detected by these detecting means as an electrical signal. It may be a processing unit such as an ECU (Electronic Control Unit) configured to be capable of this. It should be noted that the arrangement position of the detection means for directly detecting the temperature is to determine whether or not the hydraulic pressure control drive system can function normally, for example, experimentally, empirically or based on simulation. It may be determined as a possible position. Moreover, the quantity is not limited at all.

  The determining means determines whether or not the specified temperature (that is, the temperature of the hydraulic pressure control drive system) is equal to or higher than a predetermined first reference temperature. Here, the “first reference temperature” is a temperature lower than a temperature (prohibited temperature) at which vehicle speed maintenance control is to be immediately prohibited, and is previously determined experimentally, empirically, or based on simulation. When the control (typically vehicle speed maintenance control) that operates the control drive system frequently or continuously is continued, it is predicted, estimated, or estimated temperature that it will be difficult to execute the control in the near future Is set. Inevitably, the first reference temperature described here is a limit temperature at which the hydraulic control drive system itself may become inoperable, or all control operations using the hydraulic control drive system should be prohibited or executed. The temperature belongs to a temperature range lower than the temperature at which the temperature is to be kept low (both are preferably higher than the above-described prohibited temperature).

  The fact that the temperature of the hydraulic control drive system has become equal to or higher than the first reference temperature is output as warning information by the output means. The warning information is a concept that includes audio information such as an alarm or a buzzer, or visual information such as lighting of an indicator or blinking of an icon, and includes some information indicating that effect. The form of the output means inevitably changes depending on the form of the warning information.

  Here, in particular, the control of the vehicle using the hydraulic pressure control drive system is not limited to the vehicle speed maintenance control. For example, anti-lock systems such as ABS (Antilock Braking System) that prevent wheel locking, traction control systems such as TRC (TRaction Control system), or vehicle stabilization control systems such as VSC (Vehicle Stability Control) May be installed. Among these controls, there is no need to issue a warning even when the temperature of the hydraulic pressure control drive system is equal to or higher than the first reference temperature, or it can be realized alternatively by other functions provided in the vehicle. . For example, the control of ABS or the like is a relatively short-time control in an emergency, and can be executed without being relatively affected by the temperature state of the hydraulic pressure control drive system. Further, traction control such as TRC can be realized by adjusting the throttle opening and does not necessarily require the operation of the hydraulic pressure control drive system.

  However, when the warning information is output when the temperature of the hydraulic pressure control drive system becomes equal to or higher than the first reference temperature, the warning information is output to alert the continuous execution of the vehicle speed maintenance control. However, due to the nature of warning, the driver is likely to make a false determination that all functions or controls using the hydraulic control drive system are prohibited or should not be executed. If such a misjudgment occurs, unnecessary inconvenience is given to the driver, which may inevitably reduce comfort.

  Therefore, the vehicle control apparatus according to the present invention suitably solves such a problem by the output means operating as follows. That is, the output means outputs warning information when the temperature of the hydraulic pressure control drive system is equal to or higher than the first reference temperature and the execution condition described above is satisfied.

  The case where the execution condition is satisfied typically means a period during which the vehicle speed maintenance control is executed, but in addition, an input for prompting the execution of the vehicle speed maintenance control is performed and the vehicle speed maintenance control is not yet executed. It is intended to include no transitional periods. For example, according to the operation of the output means according to the present invention, when the hydraulic pressure control drive system becomes a temperature equal to or higher than the first reference temperature during execution of the vehicle speed maintenance control, at that time, and already for some reason, When the pressure control drive system is at a temperature equal to or higher than the first reference temperature, warning information is output when the execution condition is satisfied. That is, according to the vehicle control apparatus of the present invention, warning information indicating that the hydraulic control drive system is at a temperature equal to or higher than the first reference temperature is output at least when the driver executes vehicle speed maintenance control. It is limited to the situation that wants. Therefore, it is very difficult to make an erroneous determination that another control that requires the operation of the hydraulic pressure control drive system is prohibited or that it is in a state where it should be avoided. As described above, according to the vehicle control apparatus of the present invention, the comfort information is improved by effectively outputting the warning information.

  In one aspect of the vehicle control apparatus according to the present invention, the output means, when it is determined that the execution condition is satisfied and the temperature is equal to or higher than the first reference temperature, the temperature is the first The warning information is output until the temperature becomes lower than a second reference temperature defined as a temperature lower than one reference temperature.

  When the hydraulic control drive system once exceeds the first reference temperature, a cooling period is required, but when the cooling process is slow, when the temperature of the hydraulic control drive system falls below the first reference temperature When the output of the warning information is canceled, for example, there is a high possibility that the temperature of the hydraulic pressure control drive system again exceeds the first reference temperature with the execution of the vehicle speed maintenance control. That is, whether or not warning information is output is frequently switched, and unnecessary nuisance is not given to the passenger.

  According to this aspect, once the temperature of the hydraulic pressure control drive system exceeds the first reference temperature, the output means displays the warning information until the temperature falls below the second reference temperature defined as a temperature lower than the first reference temperature. Since it outputs, comfort can be improved.

  In another aspect of the vehicle control apparatus according to the present invention, the output means continuously outputs the warning information for a predetermined period.

  According to this aspect, once the warning information is output, the output of the warning information is continued for a predetermined period. For example, when the warning information output condition is not satisfied during the output of the warning information. However, the output of warning information is not interrupted. Therefore, the control load can be reduced. Note that the predetermined period is a time that can sufficiently inform the driver that the hydraulic pressure control drive system has reached the first reference temperature or higher, based on experiments, empirical experiments, or simulations in advance. It may be determined appropriately.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

<Embodiment>
Preferred embodiments of the present invention will be described below with reference to the drawings as appropriate.

<Configuration of Embodiment>
First, with reference to FIG. 1, the structure of the vehicle 10 which concerns on one Embodiment of this invention is demonstrated. Here, FIG. 1 is a schematic view of the vehicle 10.

  In FIG. 1, a vehicle 10 is an example of a “vehicle” according to the present invention, and is a four-wheel drive vehicle. The vehicle 10 includes an engine 11 that is a power source. The engine 11 is, for example, a gasoline engine. The engine 11 transmits a rotational driving force output from the engine 11 to a driving shaft 14F and a driving shaft 14R, which will be described later, and a transmission 12 and a transfer (sub-motor) for decelerating (shifting) the rotation of the rotational driving force. A transmission 13 is connected.

  The transmission 12 is configured such that the driver can select one gear from among a plurality of gears having mutually different gear ratios by operating a shift lever (not shown). Is an automatic transmission (AT) configured to be executed automatically.

  The transfer 13 is an auxiliary transmission that distributes the driving force transmitted from the transmission 12 to the front wheel side drive shaft 14F and the rear wheel side drive shaft 14R. The transfer 13 includes a differential device (center differential) therein, and absorbs a rotation difference generated between the front wheels and the rear wheels when the vehicle 10 turns.

  The front wheel side drive shaft 14F is connected to the left and right drive shafts 16FL and 16FR via a front differential 15F, and the drive shafts 16FL and 16FR are connected to wheels FL (left front wheel) and FR (right front wheel), respectively. Yes. The rear wheel side drive shaft 14R is connected to the left and right drive shafts 16RL and 16RR via a rear differential 15R. The drive shafts 16RL and 16RR include a wheel RL (left rear wheel) and a wheel RR (right rear wheel), respectively. ) Are connected. In the vehicle 10, the driving torque of the engine 11 is transmitted to each wheel through these mechanisms.

  The wheels FL, FR, RL and RR are provided with braking devices 17FL, 17FR, 17RL and 17RR, respectively. Each brake device is provided with wheel cylinders 18FL, 18FR, 18RL and 18RR, respectively, and a mechanism for braking the vehicle 10 by driving a brake member (not shown) according to the hydraulic pressure of the brake fluid. Yes. Each aspect of the braking device may have any aspect as long as the vehicle 10 can be braked, and preferably adopts an aspect such as a disc brake or a drum brake.

  The wheels FL, FR, RL and RR are provided with wheel speed sensors 19FL, 19FR, 19RL and 19RR, respectively. Each wheel speed sensor is configured to be able to detect the wheel speed and rotation direction of each wheel.

  Each wheel cylinder is normally configured so that the hydraulic pressure of the brake fluid is transmitted via the master cylinder 20, and the hydraulic pressure in the master cylinder 20 depends on the amount of depression of the brake pedal 21 by the driver. It is configured to increase or decrease. Therefore, normally, the braking force of each braking device is controlled by the driver's brake pedal operation.

  On the other hand, a brake actuator 200 is interposed between each wheel cylinder and the master cylinder 20. The brake actuator 200 is electrically connected to the ECU 100, which will be described later, and the hydraulic pressure of each wheel cylinder is increased or decreased under the control of the ECU 100 regardless of the braking operation (for example, the operation of the brake pedal 21) by the driver. Is configured to be possible. The brake actuator 200, the master cylinder 20, each braking device, and each wheel cylinder are configured to function as an example of the “braking system” according to the present invention. The brake actuator 200 is configured to function as an example of the “hydraulic pressure control drive system” according to the present invention.

  The start switch 22 is disposed at a predetermined position of the vehicle 10 such as a console panel so that the driver can operate it. When the activation switch 22 is pressed, an activation signal that prompts execution of vehicle speed maintenance control described later is output. The start switch 22 is electrically connected to the ECU 100, which will be described later, and the depression of the start switch by the driver or the like is always monitored by the ECU 100 through the input of the start signal.

  The shift position sensor 23 is a sensor that detects the position (ie, shift position) of a shift lever (not shown) for selecting the gear ratio of the transmission 12. The shift position sensor 23 is electrically connected to the ECU 100 described later, and the shift position detected by the shift position sensor 23 is output to the ECU 100 as an electric signal representing the shift position. .

  The warning buzzer output device 24 is an example of the “output means” according to the present invention configured to be able to emit a warning buzzer as an example of “warning information” according to the present invention into the vehicle interior of the vehicle 10. is there. The warning buzzer output device 24 is electrically connected to an ECU 100, which will be described later, and is configured to be controlled higher by the ECU 100.

  The temperature sensor group 25 includes a plurality of temperature sensors for detecting the temperature of the brake actuator 200, and is installed at a predetermined location in the brake actuator 200. Each of the temperature sensors constituting the temperature sensor group 25 is electrically connected to the ECU 100, and the temperature detected in each temperature sensor is output to the ECU 100 as an electrical signal.

  The ECU 100 is an electronic control unit that includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like and is configured to be able to control the entire operation of the vehicle 10. This is an example of a “vehicle control device”. The ECU 100 is configured to execute a warning process described later by executing a control program stored in the ROM.

  Further, the ECU 100 is electrically connected to the brake actuator 200, and controls the brake actuator 200 to the upper level so that the braking force applied to each wheel via the brake actuator 200 is irrelevant to the driver's braking operation. It is configured to be able to be controlled.

<Configuration of brake actuator>
Next, a part of the configuration of the brake actuator 200 will be described with reference to FIG. FIG. 2 is a schematic diagram of the brake actuator 200. In FIG. 2, the same portions as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted as appropriate. FIG. 2 also shows a brake fluid transmission path to the wheel FR as the right front wheel and the wheel RL as the left rear wheel for the sake of simplicity.

  In FIG. 2, the brake actuator 200 includes a motor 201. The motor 201 is a drive source for driving the pump 202, and the pump 202 supplied with the driving force from the motor 201 pumps the brake fluid from the reservoir 203 and supplies it to the pipe line 217 via the check valve 204. It is configured to be possible.

  A differential pressure valve 205 is disposed in a pipe line 211 connected to the master cylinder 20. The differential pressure valve 205 is an open valve that allows the brake fluid to pass in both directions when not energized, and more specifically, the downstream side (what is the master cylinder) so that the differential pressure at both ends is maintained at the target differential pressure when energized. This is a valve that functions as a pressure regulating valve that opens and closes so that the pressure on the different side is higher than the upstream side by the target differential pressure. The target differential pressure is set by the ECU 100 electrically connected to the brake actuator 200. Further, a check valve 206 is disposed in a pipe line that bypasses the differential pressure valve 205 in the pipe line 211.

  The pipe 211 is branched into pipes 213 and 214 corresponding to the wheels FR and RL, respectively, on the downstream side of the differential pressure valve 205. The pipe line 217 described above is disposed so as to join the position where the pipe line 211 branches into the pipe lines 213 and 214. Incidentally, at the upstream position of the differential pressure valve 205, the pipe line 212 is connected to the reservoir 203, and braking fluid is supplied from the reservoir 203.

  A pressure increasing valve 209 is disposed in the pipe line 213. The pressure increasing valve 209 is an electromagnetic valve whose open / close state is switched under the control of the ECU 100. Further, the pressure increasing valve 209 is configured to open when not energized. Further, the pipe line 213 further branches into the pipe line 215 at the downstream position of the pressure increasing valve 209. A pressure reducing valve 210 is disposed in the pipe line 215. The pressure reducing valve 210 is an electromagnetic valve whose open / closed state is switched under the control of the ECU 100. Further, the pressure reducing valve 210 is configured to close when not energized. On the other hand, the pipe line 214 has the same configuration as the pipe line 213, a pressure increasing valve 207 is installed on the pipe line 214, and a pressure reducing valve 208 is provided on the pressure reducing path 216 branched from the pipe line 214. The pipe lines 214 and 215 are connected to the downstream positions of the pump 202, respectively.

<Operation of Embodiment>
<Details of braking mode>
In the vehicle 10, a plurality of braking modes for braking the vehicle 10 are realized by the ECU 100 controlling the brake actuator 200. The details of a plurality of braking modes provided in the vehicle 10 will be described with reference to FIG.

<Normal braking mode>
The normal braking mode is a mode in which a braking force corresponding to the depression amount of the brake pedal 21 is applied to each wheel, in other words, a braking mode that directly reflects the driver's braking intention. When executing the normal braking mode (in this embodiment, the normal braking mode is selected by default), the ECU 100 deenergizes the differential pressure valve 205 and stops the operation of the motor 201 and the pump 202. Accordingly, the differential pressure valve 205 is simply opened, and the master cylinder pressure of the master cylinder 20 is transmitted to each wheel cylinder via the differential pressure valve 205, the pressure increasing valve 207, and the pressure increasing valve 209.

<Pressure increase mode>
In the pressure increasing mode, the ECU 100 energizes the differential pressure valve 205 and further operates the motor 201 and the pump 202. At this time, the pump 202 is driven so that a hydraulic pressure higher than the target differential pressure is applied to the differential pressure valve 205. On the other hand, since the differential pressure valve 205 opens and closes so as to maintain the differential pressure between the upstream end and the downstream end at the target differential pressure, the valve opens when the hydraulic pressure applied to the downstream side is equal to or higher than the target differential pressure. Then, the brake fluid is passed through the upstream side, which is the low pressure side. On the other hand, when the hydraulic pressure applied to the downstream side is less than the target differential pressure, the differential pressure valve 205 is closed, so that the hydraulic pressure downstream of the differential pressure valve 205 eventually becomes the target difference by repeatedly opening and closing the differential pressure valve 205. Maintained at pressure.

  In this state, the ECU 100 opens the pressure increasing valves 207 and 209 and closes the pressure reducing valves 208 and 210 while the hydraulic pressure downstream of the differential pressure valve 205 is maintained at the target differential pressure. As described above, since each pressure increasing valve is an electromagnetic valve that opens when not energized, and each pressure reducing valve is an electromagnetic valve that closes when not energized, the ECU 100 eventually energizes them in the pressure increasing mode. Not performed. The target differential pressure, which is the hydraulic pressure downstream of the differential pressure valve 205, is transmitted to each braking device via each pressure increasing valve, and the braking force applied to each wheel increases and decreases as the target differential pressure increases and decreases, respectively. Centrally controlled by differential pressure.

<Pressure reduction mode>
In the pressure reducing mode, the ECU 100 closes the pressure increasing valve 207 or the pressure increasing valve 209 and opens the pressure reducing valve 208 or the pressure reducing valve 210. In a state where the open / close state of the downstream valve is controlled in this way, the ECU 100 further drives the motor 201 and the pump 202, and causes the brake fluid in the pipe 213 or the pipe 214 to pass through the pipe 215 or the pipe 216. Suctioning up, the wheel cylinder pressure in one wheel cylinder is reduced. That is, in the decompression mode, it is possible to reduce only the braking force applied to one of the wheels.

<Retention mode>
In the holding mode, the ECU 100 closes the pressure increasing valve 207 and the pressure reducing valve 208 or the pressure increasing valve 209 and the pressure reducing valve 210. In this state, the hydraulic pressure applied to each wheel cylinder at the present time is maintained. The holding mode is selected, for example, to hold the reduced pressure state for a certain period after the reduced pressure mode is executed.

<Vehicle control>
The ECU 100 can selectively execute the various braking modes described above by controlling the brake actuator 200. The ECU 100 is configured to be able to execute vehicle speed maintenance control, antilock control, and traction control as control that uses such a function of the brake actuator 200.

  The vehicle speed maintenance control is control for maintaining the vehicle speed below the target vehicle speed when the vehicle 10 descends the slope. The ECU 100 receives the above-described start signal from the start switch 22 and when the shift position of the transmission 12 is at the “L” or “R” position where the gear ratio can be maximized in each of the forward and backward travels (that is, the present position). An example of “when the execution condition is satisfied” according to the invention), vehicle speed maintenance control is executed so as to maintain the vehicle speed of the vehicle 10 on the downhill slope at the target vehicle speed. During the execution of the vehicle speed maintenance control, the ECU 100 controls the brake actuator 200 based on the wheel speed detected by the wheel speed sensor disposed on each wheel, thereby selectively selecting the pressure increasing mode and the pressure reducing mode described above. Execute and maintain the vehicle speed at the target vehicle speed.

  Anti-lock control is executed when the wheel is locked. The ECU 100 determines whether or not each wheel is in a locked state based on the output of the wheel speed sensor arranged on each wheel, and reduces the braking force to the locked wheel through the above-described decompression mode. To release the lock. The anti-lock control is executed not only when the driver performs a sudden braking operation (such as a sudden brake) but also during the vehicle speed maintenance control described above.

  Unlike anti-lock control, traction control brakes the wheel on which the spin occurred when a spin (excessive rotation) occurs due to the driving force (traction) exceeding the amount that can be transmitted to the wheel. This is one type of vehicle stabilization control that maintains the stability of the vehicle 10. In this case, for example, the ECU 100 controls the braking mode for the wheels other than the spun wheels to the holding mode, and increases the braking force for the spun wheels through the pressure increasing mode.

<Details of warning processing>
The brake actuator 200 may increase in temperature in the course of executing the various controls described above or regardless of whether or not the various controls described above are performed. For example, among the various controls described above, vehicle speed maintenance control that requires the brake actuator 200 to be operated frequently and continuously for a long time may promote such a temperature increase. Therefore, it is desirable to notify the passenger that the temperature of the brake actuator 200 is rising. On the other hand, anti-lock control and traction control, which are instantaneous braking force control, have a smaller load applied to the brake actuator 200 than the vehicle speed maintenance control, and are less likely to promote such a temperature rise. The temperature or the temperature estimated to be difficult to execute in the near future is sufficiently higher than the vehicle speed maintenance control. However, when the increase in temperature of the brake actuator 200 is transmitted, it is easy for the driver to be misunderstood that the control that can be performed originally is affected. Therefore, in the present embodiment, the ECU 100 executes a warning process to effectively warn that the temperature of the brake actuator 200 is rising.

  Here, the details of the warning process will be described with reference to FIG. FIG. 3 is a flowchart of the warning process.

  In FIG. 3, the ECU 100 first determines whether or not the temperature of the brake actuator 200 is a warning target temperature (step A10). The ECU 100 always executes the temperature determination process in parallel with the warning process, and performs the determination based on the result of the temperature determination process. Here, the details of the temperature determination process will be described with reference to FIG. FIG. 4 is a flowchart of the temperature determination process.

  In FIG. 4, the ECU 100 calculates the actuator temperature T from the sensor output input from the temperature sensor group 25 based on a predetermined calculation formula (step B10). Next, it is determined whether or not the calculated actuator temperature T is equal to or higher than the first reference temperature Ta (that is, an example of the “first reference temperature” according to the present invention) (step B11).

  When the actuator temperature T is equal to or higher than the first reference temperature Ta (step B11: YES), the ECU 100 determines that the temperature of the brake actuator 200 is the warning target temperature and indicates that the warning target temperature has been reached in advance. Is updated to a value indicating that the warning target temperature has been reached (step B12). When the process related to step B12 is executed or the actuator temperature T is lower than the first reference temperature Ta (step B11: NO), the ECU 100 determines that the actuator temperature T is equal to the second reference temperature Tb (Tb <Ta, that is, It is determined whether or not the temperature is lower than (an example of “second reference temperature” according to the present invention) (step B13).

  When the actuator temperature T is lower than the second reference temperature Tb (step B13: YES), the ECU 100 determines that the temperature of the brake actuator 200 is not the warning target temperature, and uses the above-described determination value stored in the RAM in advance. The value is updated to indicate that the temperature is not the warning target temperature (step B14).

  When the process according to step B14 is executed or when the actuator temperature T is equal to or higher than the second reference temperature Tb (step B13: NO), the ECU 100 returns the process to step B10 and calculates the actuator temperature T again. The series of processes described above are executed. When the actuator temperature T is lower than the first reference temperature Ta and equal to or higher than the second reference temperature Tb (that is, step B11: NO and step B13: NO), the aforementioned determination value is maintained at the previous value. The Further, the determination value is a value indicating that the brake actuator 200 has not reached the warning target temperature in the default state, and in the process related to Step B13 that is first started after the temperature determination process is started, that is, the second reference. It is determined that the brake actuator 200 has not reached the warning target temperature regardless of whether or not it is less than the value Tb.

  As described above, in the temperature determination process, basically, when the actuator temperature T is equal to or higher than the first reference temperature Ta, it is determined that the temperature of the brake actuator 200 has reached the warning target temperature. Further, when the actuator temperature T once becomes equal to or higher than the first reference temperature Ta, the determination is maintained until the actuator temperature T becomes lower than the second reference temperature Tb that is a value lower than the first reference temperature Ta. Is done.

  Returning to FIG. 3, in the process according to step A10, the ECU 100 refers to the above-described determination value stored in the RAM in the course of the temperature determination process, and at that time, the temperature of the brake actuator 200 reaches the warning target temperature. It is determined whether or not. When the temperature of the brake actuator 200 has not reached the warning target temperature (step A10: NO), the ECU 100 resets the buzzer counter (step A15). The buzzer counter is a timer that counts the warning buzzer sounding time, and is set to “0” by the processing related to step A15. In this embodiment, the warning buzzer sounding time is set to 3 seconds. When the process related to step A15 ends, the process proceeds to step A16. The process related to step A16 will be described later.

  When the temperature of the brake actuator 200 has reached the warning target temperature (step A10: YES), the ECU 100 determines whether or not the start switch 22 has been pressed (step A11). Whether or not the activation switch 22 is pressed is determined based on the presence or absence of the activation signal described above. When the activation switch is not pressed (step A11: NO), the ECU 100 proceeds to step A15.

  If the start switch 22 is pressed (step A11: YES), the ECU 100 determines whether or not a warning buzzer is output (sound emission) (step A12). When the warning buzzer is not output (step A12: NO), the ECU 100 further determines whether or not the shift position is at the “L” or “R” position (step A13). Such determination is made based on the sensor output input from the shift position sensor 23.

  When the shift position is in the “L” or “R” position (step A13: YES), that is, the start switch 22 is pressed, the shift position is the predetermined position, and the temperature of the brake actuator 200 reaches the warning target temperature. If so, the ECU 100 controls the warning buzzer output device 24 to output a warning buzzer to the vehicle interior of the vehicle 10 (step A14). On the other hand, when the shift position is not in the “L” or “R” position (step A13: NO), the ECU 100 proceeds to step A15 assuming that the “execution condition” according to the present invention is not satisfied.

  When the warning buzzer is output by the processing according to step A15 or when the warning buzzer has already been output (step A12: YES), the ECU 100 determines whether or not the warning buzzer is sounded for a predetermined time (ie, 3 seconds). Is discriminated (step A17).

  When the processing according to step A15 is executed or the warning buzzer is sounded for a predetermined time (step A17: YES), the ECU 100 controls the warning buzzer output device 24 to stop the output of the warning buzzer (step A16).

  When the process according to step A16 is executed or when the warning buzzer has not been sounded for a predetermined time (step A17: NO), the ECU 100 returns the process to step A10 and performs a series of operations based on the temperature of the brake actuator 200. Repeat the process.

  Here, even if the warning buzzer is sounded and the predetermined time has not elapsed, if the temperature of the brake actuator 200 has not reached the warning target temperature, the buzzer counter is reset and the output of the warning buzzer is stopped. Is done. On the other hand, in the process according to step A12, the shift position is referred only when the warning buzzer is not output, and the execution condition of the vehicle speed maintenance control is during the period when the warning buzzer continues to sound. Even when it is not satisfied (that is, when the shift position is changed), the warning buzzer continues to sound. Thereby, the intermittent sounding of the warning buzzer is prevented.

  As described above, according to the warning process according to the present embodiment, the warning buzzer output is output only when the temperature of the brake actuator 200 is the warning target temperature and the execution condition of the vehicle speed maintenance control is seen. Be started. Therefore, for the driver, a warning buzzer is output when he / she tries to execute the vehicle speed maintenance control, so that all control using the brake actuator 200 becomes difficult or is not executed. The risk of misunderstanding that it should be avoided is significantly reduced. That is, unnecessary troublesomeness is eliminated and comfort is improved.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification. Is also included in the technical scope of the present invention.

It is a mimetic diagram of a vehicle concerning one embodiment of the present invention. It is a schematic diagram of the brake actuator with which the vehicle of FIG. 1 is equipped. It is a flowchart of the warning process which ECU performs in the vehicle of FIG. It is a flowchart of the temperature determination process which ECU performs in the vehicle of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Vehicle, 11 ... Engine, 22 ... Start switch, 23 ... Shift position sensor, 24 ... Warning buzzer output device, 25 ... Temperature sensor group, 100 ... ECU, 200 ... Brake actuator.

Claims (3)

A vehicle control device for controlling a vehicle including a braking system including a hydraulic pressure control drive system for controlling the hydraulic pressure of braking fluid,
Control means for controlling the braking system so that the speed when the vehicle descends the slope is maintained below a predetermined value when a predetermined execution condition is satisfied;
Specifying means for specifying the temperature of the hydraulic control drive system;
Determining means for determining whether or not the temperature is equal to or higher than a predetermined first reference temperature;
An output means for outputting predetermined warning information when it is determined that the execution condition is satisfied and the temperature is equal to or higher than the first reference temperature. The output means has a second reference temperature defined as a temperature lower than the first reference temperature when the execution condition is satisfied and the temperature is determined to be equal to or higher than the first reference temperature. The vehicle control device according to claim 1, wherein the warning information is output until the value becomes less than the value. The vehicle control apparatus according to claim 1, wherein the output unit continuously outputs the warning information for a predetermined period.

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