JP5365205B2 - Vehicle exercise support apparatus and vehicle exercise support method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid amount estimation device and a motion supporting device for a vehicle performing liquid elimination control for eliminating liquid between a first braking member and a second braking member at a proper timing considering liquid in a mist state blown up by a preceding vehicle. <P>SOLUTION: When it rains, an ECU obtains vehicle body speed VS of an own vehicle, working cycle FS of a wiper and an inter-vehicle distance Lp between the own vehicle and a preceding vehicle (Step S13 to S15). The ECU sets a unit growth amount &Delta;Wl corresponding to the inter-vehicle distance Lp, vehicle body speed VS and working cycle FS, a first gain A and a second gain B, and multiplies the unit growth amount &Delta;Wl by both of the gains A, B. The multiplication result is considered as a real growth amount &Delta;W (step S16). The ECU updates moisture film thickness W on a slide contact face of a brake rotor (step S17) and performs moisture eliminating control for bringing a brake pad into slide contact with the brake rotor (step S18) when the updated moisture film thickness W is equal to or larger than a film thickness threshold value KW. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention is for removing liquid such as moisture existing between a first braking member such as a brake rotor that rotates together with a wheel and a second braking member such as a brake pad that can come into contact with the first braking member. The present invention relates to a vehicle motion support apparatus and a vehicle motion support method for performing control.

  2. Description of the Related Art Generally, a disc brake device having a brake rotor as a first braking member that rotates with a wheel and a brake pad as a second braking member that can slide in contact with the rotating brake rotor is provided for each vehicle. It is installed. In such a disc brake device, when the brake pad is brought into sliding contact with the brake rotor, the greater the pressing force that the brake pad applies to the brake rotor, the greater the braking force is applied to the wheels.

  However, when the vehicle is driven in rainy weather, rain water or the like bounces off the road surface, or mist-like water that is rolled up by the rotating wheels adheres to the brake pad, brake rotor, or the like. As the amount of moisture (liquid amount) adhering to such brake pads and brake rotors increases, there is a problem that the efficiency of applying braking force to the wheels by the disc brake device decreases. Therefore, in recent years, an exercise support device described in Patent Document 1 has been proposed as a device for applying a suitable braking force to wheels even during rain.

  When the wiper mounted on the vehicle operates, the exercise support apparatus determines that it is raining, and measures the elapsed time since the last braking force is applied to the wheels. In addition, the exercise support apparatus sets an elapsed time threshold corresponding to the vehicle body speed of the vehicle and the operation cycle of the wiper for each predetermined cycle (for example, “1 second”). When the elapsed time to be measured exceeds the elapsed time threshold value at that time, the exercise support device applies the braking force due to the increased amount of moisture adhering to the brake pad or the brake rotor. It is determined that there is a possibility that the efficiency has been lowered, and moisture removal control (liquid removal control) is performed to apply a braking force of a magnitude that is not felt by the driver to the wheels. As a result, moisture is removed from the brake pad and the brake rotor by a frictional force generated between the brake pad and the brake rotor. Therefore, when a braking control or a braking operation by the driver is subsequently executed, a suitable braking force is applied to the wheels.

US Pat. No. 5,570,937

  By the way, when the vehicle travels in rainy weather, a part of the mist-like water that is rolled up by the rear wheel of the vehicle traveling forward (hereinafter referred to as “front vehicle”) adheres to the brake pad, the brake rotor, or the like. Sometimes. The amount of moisture present between the brake pad and the brake rotor due to the mist-like moisture that the preceding vehicle rolls up changes depending on the distance between the preceding vehicle and the preceding vehicle. However, the conventional exercise support apparatus does not take into consideration the mist-like water that is wound up by the rear wheel of the preceding vehicle. For this reason, it is difficult to say that the moisture removal control is executed at an appropriate timing.

  The present invention has been made in view of such circumstances, and an object of the present invention is to perform liquid removal control for removing the liquid existing between the first braking member and the second braking member. It is an object of the present invention to provide a liquid amount estimation device and a vehicle motion support device that can be executed at an appropriate timing in consideration of a mist-like liquid wound up from the vehicle.

In order to achieve the above object, the invention according to claim 1 relating to a vehicle movement support device includes a first braking member (50) that rotates together with wheels (FR, FL, RR, RL), and the rotation. Mounted on a vehicle having a second braking member (51, 52) capable of applying a braking force to the wheels (FR, FL, RR, RL) by contacting the first braking member (50). When the liquid exists between the braking members (50, 51, 52), the liquid removal is performed by bringing the second braking member (51, 52) into contact with the first braking member (50) in order to remove the liquid. Situation determination for determining whether or not a liquid can enter between the braking members (50, 51, 52) in the vehicle movement support device including control means (16, S19) for executing control. Means (16, S10) and forward vehicle traveling forward Vehicle distance obtaining means for obtaining inter-vehicle distance (Lp) between C2) (16, S15 and), further wherein the situation determining means (16, S10) said judges each braking member (50, 51, 52) The situation in which the liquid can enter between is a situation in which the road surface is wet during or after the precipitation, and the control means (16, S19) is controlled by the situation determination means (16, S10). When it is determined that the liquid can enter between the braking members (50, 51, 52), the earlier the timing, the shorter the inter-vehicle distance (Lp) acquired by the inter-vehicle distance acquisition means (16, S15). The gist is to execute the liquid removal control .

  Generally, when the liquid can enter between the first braking member and the second braking member, a large amount of mist-like liquid is wound up from the rear wheel of the vehicle. A part of such mist-like liquid enters between the brake members of the vehicle traveling behind. Moreover, the degree of increase in the amount of liquid existing between the braking members increases as the inter-vehicle distance from the preceding vehicle is shorter. Therefore, in the present invention, when the liquid can enter between the brake members, the execution timing of the liquid removal control is set to be earlier as the inter-vehicle distance from the preceding vehicle is shorter. Therefore, the liquid removal control for removing the liquid existing between the first braking member and the second braking member can be executed at an appropriate timing in consideration of the inter-vehicle distance from the preceding vehicle.

  According to a second aspect of the present invention, in the vehicle exercise support apparatus according to the first aspect, the vehicle further includes vehicle body speed acquisition means (16, S13) for acquiring the vehicle body speed (VS) of the vehicle, and the control means (16 , S19) is the vehicle body speed acquisition means (16) when it is determined by the situation determination means (16, S10) that the liquid can enter between the braking members (50, 51, 52). The liquid removal control is executed at an earlier timing as the vehicle body speed (VS) acquired in S13) is faster.

  According to the above configuration, the execution timing of the liquid removal control is set to a timing that considers not only the inter-vehicle distance from the preceding vehicle but also the vehicle body speed. Therefore, the liquid removal control can be executed at a more appropriate timing.

  According to a third aspect of the present invention, in the vehicle exercise support apparatus according to the first or second aspect, the vehicle further comprises a precipitation acquisition means (16, S14) for acquiring precipitation on the vehicle at the time of precipitation, and the control. The means (16, S19) obtains the precipitation amount when it is determined by the situation determination means (16, S10) that the liquid can enter between the braking members (50, 51, 52). The gist is that the liquid removal control is executed at an earlier timing as the amount of precipitation acquired by the means (16, S14) increases.

  According to the above configuration, the execution timing of the liquid removal control is set to a timing that considers not only the inter-vehicle distance from the preceding vehicle but also precipitation. Therefore, the liquid removal control can be executed at a more appropriate timing.

  According to a fourth aspect of the present invention, in the vehicle movement support device according to the second or third aspect, the control means (16, S19) is configured such that each of the braking members is controlled by the situation determination means (16, S10). In the case where it is determined that the liquid can enter between (50, 51, 52), the first position (P1) where the liquid is wound up toward the own vehicle (C1) by the preceding vehicle (C2). ) To the second position (P2) where the rolled-up liquid lands on the road surface, and from when the liquid is rolled up by the preceding vehicle (C2) until it lands on the road surface. When the sum (Lw + Lv) with the travel distance (Lv) of the vehicle (C1) between the two is greater than the inter-vehicle distance (Lp) acquired by the inter-vehicle distance acquisition means (16, S15), the sum (Lw + Lv) The car Distance performing said liquid removal controlled at a timing earlier than when it is less than (Lp) is summarized as.

  According to the above configuration, the liquid removal control is executed at an earlier timing when the liquid rolled up toward the own vehicle by the preceding vehicle is likely to adhere to each braking member of the own vehicle compared to the case where the liquid is less likely to adhere. Is done.

  According to a fifth aspect of the present invention, in the vehicle movement support device according to any one of the first to fourth aspects, the braking member (50, 51) is provided by the situation determination means (16, S10). , 52), it is determined that the liquid can enter between the braking members (50, 51, 52) in a predetermined cycle set in advance (ΔW). Unit increase amount estimation means (16, S16) for estimating the vehicle distance so as to increase as the inter-vehicle distance (Lp) acquired by the inter-vehicle distance acquisition means (16, S15) becomes shorter. The amount of increase (ΔW) of the liquid estimated by the amount estimating means (16, S16) is integrated, and the liquid amount of the liquid existing between the brake members (50, 51, 52) based on the integration result ( Liquid volume calculation to calculate W) Calculating means (16, S17), wherein the control means (16, S19) is arranged between the braking members (50, 51, 52) calculated by the liquid amount calculating means (16, S17). In summary, the liquid removal control is executed when the liquid amount (W) of the liquid existing in the liquid crystal is greater than or equal to a preset liquid amount threshold (KW).

  According to the above configuration, the increase amount of the liquid existing between the braking members in a predetermined cycle set in advance is estimated so as to increase as the inter-vehicle distance from the preceding vehicle becomes shorter. Then, the increase amount estimated for each predetermined period is integrated, and the integration result is used as the liquid amount of the liquid existing between the braking members. Liquid removal control is executed when the liquid amount calculated in this way is equal to or greater than a preset liquid amount threshold. As a result, since the liquid existing between the respective braking members is removed, an appropriate braking force is applied to the wheels during the subsequent braking operation and braking control.

  According to a sixth aspect of the present invention, in the vehicle motion support device according to any one of the first to fourth aspects, a braking force is applied to the wheels (FR, FL, RR, RL). The elapsed time measuring means (16, S32) for measuring the elapsed time (T) after being applied, and the situation determining means (16, S10) allow liquid to enter between the brake members (50, 51, 52). The vehicle distance (Lp) acquired by the vehicle distance acquisition means (16, S15) as the elapsed time threshold (KT) for determining the execution timing of the liquid removal control when it is determined that the situation is to be obtained. Threshold value setting means (16, S30) for setting the value so as to decrease as the time becomes shorter, and the control means (16, S19) is an elapsed time measured by the elapsed time measurement means (16, S32) ( T) , If the the threshold value setting means (16, S30) the elapsed time threshold (KT) or set by, and be required to perform the liquid removal control.

  According to the above configuration, the elapsed time threshold value for determining the execution timing of the liquid removal control is estimated so as to decrease as the inter-vehicle distance from the preceding vehicle decreases. And liquid removal control is performed when the elapsed time after braking force is provided with respect to a wheel becomes more than an elapsed time threshold value. As a result, since the liquid existing between the respective braking members is removed, an appropriate braking force is applied to the wheels during the subsequent braking operation and braking control.

On the other hand, the invention according to claim 7 according to the vehicle motion support method is configured to rotate with the first braking member (50) rotating together with the wheels (FR, FL, RR, RL) mounted on the vehicle. When liquid is present between the first braking member (50) and the second braking member (51, 52) capable of applying a braking force to the wheels (FR, FL, RR, RL) by contacting the first braking member (50), In the vehicle exercise support method, the vehicle braking support method includes an execution step (S19) of performing liquid removal control for removing the liquid by bringing the second braking member (51, 52) into contact with the first braking member (50). Inter-vehicle distance (Lp) between the situation determination step (S10) for determining whether or not the liquid can enter between the braking members (50, 51, 52) and the preceding vehicle (C2) traveling forward. Inter-vehicle distance acquisition step (S1 ) And, further comprising, the situation and circumstances that may enter the fluid during the respective braking members determining step (S10) (50, 51, 52) during precipitation, or road surface after rainfall When it is determined that in the execution step (S19) the liquid is allowed to enter between the braking members (50, 51, 52) in the execution step (S19) in the execution step (S19). Furthermore, the gist is that the liquid removal control is executed at an earlier timing as the inter-vehicle distance (Lp) acquired in the inter-vehicle distance acquisition step (S15) is shorter.

  According to the said structure, the effect equivalent to the invention of Claim 1 can be acquired.

The block diagram of the vehicle carrying the brake device in 1st Embodiment. The block diagram which shows a part of braking device in 1st Embodiment. (A) (b) is sectional drawing which shows a disc brake apparatus typically. A map for estimating unit growth based on the distance between vehicles. A map for setting the first gain based on the vehicle body speed of the vehicle. A map for setting the second gain based on the operation cycle of the wiper. The action figure which shows typically the relationship between the inter-vehicle distance between the own vehicle and a preceding vehicle and the amount of mist-like water adhering to the front wheel of the own vehicle. The flowchart explaining the precipitation countermeasure process routine in 1st Embodiment. The action figure which shows typically the relationship between the inter-vehicle distance between the own vehicle and a preceding vehicle and the amount of mist-like water adhering to the front wheel of the own vehicle. The action figure which shows typically the relationship between the inter-vehicle distance between the own vehicle and a preceding vehicle and the amount of mist-like water adhering to the front wheel of the own vehicle. A map for estimating a temporary time threshold based on the inter-vehicle distance. The flowchart explaining a part of precipitation countermeasure processing routine in 2nd Embodiment. The action figure which shows typically a mode that the front wheel of the own vehicle gets wet with the mist-like water wound up by the preceding vehicle which drive | works the lane different from the lane which the own vehicle drive | works.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. In the following description of the present specification, the traveling direction (forward direction) of the vehicle is assumed to be the front (front of the vehicle). Unless otherwise specified, the left-right direction in the following description is the same as the left-right direction in the vehicle traveling direction.

  As shown in FIG. 1, the vehicle of this embodiment is an automatic four-wheel vehicle having a right front wheel FR, a left front wheel FL, a right rear wheel RR, and a left rear wheel RL, and a driver depresses an accelerator pedal (not shown). The vehicle travels by transmitting a driving force based on the operation to driving wheels (for example, rear wheels RR, RL). Such a vehicle includes a wiper device 12 for wiping off water droplets (liquid) such as rain water and snow that has landed on the windshield 11 of the vehicle, and a vehicle traveling forward (hereinafter referred to as a “front vehicle”). And an inter-vehicle distance measuring device ACC for measuring the inter-vehicle distance. Further, the vehicle is connected to a hydraulic pressure generating device 14 for generating a brake hydraulic pressure as a hydraulic pressure based on a depression operation of the brake pedal 13 by a driver, and connected to the hydraulic pressure generating device 14, and each wheel FR, FL , RR, and RL are provided with a braking device 15 for applying a braking force. The driving of the braking device 15 is controlled by an electronic control device (hereinafter referred to as “ECU”) 16 as an exercise support device. Further, the vehicle is provided with a disc brake device 17 that applies a braking force to the wheels FR, FL, RR, RL based on a depression operation of the brake pedal 13 by the driver or driving of the braking device 15, and the wheels FR, FL, RR, RL. Each is provided on the upper part of the wheels FR, FL, RR, RL.

Next, the wiper device 12 will be described with reference to FIG.
The wiper device 12 includes a plurality of (in this embodiment, two) wipers 18 for wiping the windshield 11 and a driver for adjusting the operation cycle (also referred to as “operation speed”) of each wiper 18. A wiper operation unit 19 (also referred to as “wiper switch”) to be operated is provided. In the wiper device 12, the operation cycle of the wiper 18 is a long cycle (“L” in FIG. 1), a middle cycle (“M” in FIG. 1), and a short cycle (in FIG. 1) by the operation of the wiper operation unit 19 by the driver. “H”) and can be adjusted in multiple stages. Further, when the wiper operation unit 19 is set to be “OFF” shown in FIG. 1, the operation of the wiper 18 is stopped. A detection signal corresponding to the operating cycle of the wiper 18 is output from the wiper operation unit 19 to the ECU 16.

Next, the inter-vehicle distance measuring device ACC will be described with reference to FIG.
The inter-vehicle distance measuring device ACC includes an emission unit (not shown) that emits laser light forward from a vehicle (hereinafter referred to as “own vehicle” to be distinguished from the preceding vehicle), and a laser emitted from the emission unit. And a light receiving unit (not shown) that receives the reflected light reflected by the vehicle in front of the light. The inter-vehicle distance measuring device ACC measures the time from when the laser beam is emitted from the emitting unit to when the reflected light is received by the light receiving unit, and based on the measured time, the relative distance of the preceding vehicle to the host vehicle is measured. A measurement unit (not shown) for measuring the speed and the inter-vehicle distance Lp (see FIG. 7) between the host vehicle and the preceding vehicle is provided. The measurement unit is electrically connected to the ECU 16, and various information regarding the relative speed of the preceding vehicle with respect to the own vehicle and the inter-vehicle distance Lp between the own vehicle and the preceding vehicle is transmitted from the measurement unit to the ECU 16. Sent.

Next, the hydraulic pressure generator 14 will be described with reference to FIGS. 1 and 2.
As shown in FIGS. 1 and 2, the hydraulic pressure generator 14 includes a master cylinder 20 and a booster 21. In the hydraulic pressure generation device 14, when the driver depresses the brake pedal 13 (hereinafter referred to as “brake operation”), the master cylinder 20 and the booster 21 operate. Then, brake fluid is supplied from the master cylinder 20 into each wheel cylinder provided for each of the wheels FR, FL, RR, and RL. As a result, a braking force corresponding to the wheel cylinder pressure in each wheel cylinder is applied to each of the wheels FR, FL, RR, and RL. The hydraulic pressure generator 14 is provided with a brake switch SW1 for detecting that the brake pedal 13 has been depressed, and the brake switch SW1 is adapted to the operation mode of the brake pedal 13 by the driver. A detection signal is output to the ECU 16.

  Next, the braking device 15 will be described with reference to FIGS. The braking device 15 has two hydraulic circuits 22 and 23 having substantially the same configuration. Therefore, in FIG. 2, only one hydraulic circuit 22 is illustrated and the other hydraulic circuit 23 is not illustrated for convenience of understanding the description of the specification.

  As shown in FIGS. 1 and 2, the braking device 15 according to the present embodiment has two hydraulic circuits 22 and 23. The hydraulic pressure circuits 22 and 23 are connected to the master cylinder 20 of the hydraulic pressure generating device 14, and the first hydraulic pressure circuit 22 is provided corresponding to the left front wheel FL and the right rear wheel RR. The second hydraulic circuit 23 is connected to each wheel cylinder (not shown) provided corresponding to the right front wheel FR and the left rear wheel RL.

  The first fluid pressure circuit 22 is formed with a connection flow path 26 connected to the master cylinder 20. The connection flow path 26 includes a master cylinder pressure in the master cylinder 20 and wheel cylinders 24, 25. A proportional differential pressure valve 27 for generating a pressure difference with the wheel cylinder pressure is provided. The proportional differential pressure valve 27 includes a valve seat and a valve body (not shown), and the valve body is moved to a position corresponding to the magnitude of current supplied from the ECU 16. In the proportional differential pressure valve 27 of the present embodiment, the passage formed between the valve seat and the valve element is a wheel cylinder 24 on the master cylinder 20 side of the proportional differential pressure valve 27 and the opposite side of the master cylinder 20. In order to generate a pressure difference with the 25 side, the orifice is narrower than the connecting flow path 26 even when power is not supplied from the ECU 16.

  The first hydraulic circuit 22 includes a left front wheel path 28 connected to the wheel cylinder 24 and a right rear wheel path 29 connected to the wheel cylinder 25. On each of the paths 28 and 29, normally-open first electromagnetic valves 30 and 31 (also referred to as “holding valves”) that operate when the increase in the wheel cylinder pressure in the wheel cylinders 24 and 25 is regulated. And normally closed second electromagnetic valves 32 and 33 (also referred to as “pressure reducing valves”) that operate when the wheel cylinder pressure in the wheel cylinders 24 and 25 is reduced.

  Further, the first hydraulic circuit 22 operates based on the rotation of the motor MT and a reservoir 34 for temporarily storing brake fluid flowing out from the wheel cylinders 24 and 25 through the second electromagnetic valves 32 and 33. And a pump 35 is provided. The pump 35 is connected to the reservoir 34 via the suction flow path 36, and is connected to the first electromagnetic valves 30 and 31 and the proportional differential pressure valve 27 in the first hydraulic circuit 22 via the supply flow path 37. It is connected to the connection part 38 between. Further, a branch hydraulic pressure path 39 branched toward the master cylinder 20 side is formed in the suction flow path 36. Then, when the motor MT rotates, the pump 35 sucks the brake fluid from the reservoir 34 and the master cylinder 20 via the suction passage 36 and the branch hydraulic pressure passage 39, and supplies the brake fluid to the supply passage. It discharges in 37.

  The second hydraulic circuit 23 has a configuration equivalent to that of the first hydraulic circuit 22. Therefore, the wheel cylinder pressure in each wheel cylinder for the right front wheel FR and the left rear wheel RL is adjusted by individually operating various solenoid valves and pumps provided on the second hydraulic pressure circuit 23, respectively. .

  Next, the disc brake device 17 will be described with reference to FIGS. Since the disc brake devices 17 provided for the respective wheels FR, FL, RL, RR have substantially the same configuration, only the disc brake device 17 for the left front wheel FL will be described, and the other wheels FR. The description of the disc brake device 17 for RR and RL will be omitted.

  As shown in FIGS. 3A and 3B, the disc brake device 17 includes an annular brake rotor 50 as a first braking member that rotates integrally with the left front wheel FL. In addition, the disc brake device 17 is provided with brake pads 51 and 52 as second braking members arranged in a state of facing the first sliding contact surface 50 a and the second sliding contact surface 50 b of the brake rotor 50. ing. Each of the brake pads 51 and 52 is given a biasing force in a direction away from the brake rotor 50 by a biasing mechanism (not shown). Therefore, when the brake fluid does not flow into the wheel cylinder 24 from the braking device 15 side, the brake pads 51 and 52 have clearances C of a predetermined interval between the respective sliding contact surfaces 50a and 50b facing each other. Each is arranged in the state.

  On the other hand, when the brake fluid flows into the wheel cylinder 24 from the braking device 15 side, the brake pads 51 and 52 are given a driving force corresponding to the amount of the brake fluid inflow, thereby the brake rotor 50. Each is configured so as to be relatively close to each other. When the brake fluid further flows into the wheel cylinder 24 in a state where the brake pads 51 and 52 are in sliding contact with the sliding contact surfaces 50 a and 50 b of the brake rotor 50, the brake pads 51 and 52 move the brake rotor 50. Press each other. As a result, a braking force having a magnitude corresponding to the amount of brake fluid in the wheel cylinder 24, that is, the wheel cylinder pressure is applied to the left front wheel FL.

  In addition, when the road surface is wet due to rain or the like, each brake rotor 50 may be rebounded by rain water from the road surface, or mist-like water that is rolled up by the preceding vehicle and the own vehicle. In this case, moisture films are formed on the sliding contact surfaces 50a and 50b of the brake rotors 50, respectively. Thus, the growth amount of the moisture film formed on the sliding contact surfaces 50a and 50b of each brake rotor 50 (that is, the increase amount of moisture existing between the brake rotor 50 and the brake pads 51 and 52) is It increases as the mileage becomes longer and precipitation increases. Therefore, a situation where the road surface is wet due to precipitation or the like means that a moisture film can be formed on the sliding contact surfaces 50a and 50b of each brake rotor 50 (that is, moisture is formed between the brake rotor 50 and the brake pads 51 and 52). It can be said that the situation can be entered. In the present embodiment, “precipitation” is a state in which a moisture film formed on the sliding contact surfaces 50a and 50b of the brake rotor 50 grows as the vehicle travels. It is a phenomenon that includes falling, artificially raining, or spraying water on the road surface on which the vehicle travels.

Next, the configuration of the ECU 16 will be described with reference to FIG.
As shown in FIG. 1, an input side interface (not shown) of the ECU 16 includes a brake switch SW1, wheel speed sensors SE1, SE2, SE3, SE4 for calculating wheel speeds of the wheels FR, FL, RR, RL, a wiper. The wiper operation unit 19 of the device 12 and the inter-vehicle distance measuring device ACC are electrically connected. Further, the proportional differential pressure valve 27, the first electromagnetic valves 30, 31, the second electromagnetic valves 32, 33, and the motor MT are electrically connected to an output side interface (not shown) of the ECU 16. Then, based on the detection signals from the brake switch SW1, the wheel speed sensors SE1 to SE4 and the wiper operation unit 19, the ECU 16 sets the proportional differential pressure valves 27, the first electromagnetic valves 30, 31, and the second electromagnetic valves 32, 33. And the operation of the motor MT is individually controlled.

  The ECU 16 is provided with a CPU 55, a ROM 56, and a RAM 57. In the ROM 56, various control processes (such as a precipitation countermeasure process described later), various maps (such as the various maps shown in FIGS. 4, 5, and 6), various thresholds (such as a film thickness threshold described later), and the like are stored in advance. Yes. The RAM 57 stores various information (wheel speed, vehicle speed, operation cycle, inter-vehicle distance, actual growth amount, moisture film thickness, etc., which will be described later) that can be appropriately rewritten while the ignition switch (not shown) of the vehicle is “ON”. Temporarily stored.

Next, various maps stored in the ROM 56 will be described with reference to FIGS.
The first map shown in FIG. 4 shows the amount of moisture film growth per unit time (hereinafter referred to as “unit growth amount”) on the sliding contact surfaces 50a, 50b of the brake rotor 50 between the host vehicle and the preceding vehicle. This is a map for estimation based on the inter-vehicle distance Lp (hereinafter simply referred to as “inter-vehicle distance”). As shown in FIG. 4, the unit growth amount ΔWl of the moisture film is set to the first growth amount ΔWl1 when the inter-vehicle distance Lp exceeds a preset inter-vehicle distance threshold Lpth. Further, the unit growth amount ΔWl of the moisture film is a second larger than the first growth amount ΔWl1 when the inter-vehicle distance Lp is equal to or less than the inter-vehicle distance threshold Lpth and exceeds half of the inter-vehicle distance threshold Lpth (= Lpth / 2). The growth amount is ΔWl2. The unit growth amount ΔWl of the moisture film is set to a third growth amount ΔWl3 that is greater than the second growth amount ΔWl2 when the inter-vehicle distance Lp is equal to or less than half the inter-vehicle distance threshold Lpth (= Lpth / 2). That is, the unit growth amount ΔWl set based on the inter-vehicle distance Lp is set so as to increase as the inter-vehicle distance Lp becomes shorter. The “unit time” in the present embodiment is a time corresponding to a predetermined cycle that is an interval at which a precipitation countermeasure processing routine described later is repeatedly executed. Therefore, when the precipitation countermeasure processing routine is executed every “6 msec. (Milliseconds)”, the unit time is set to “6 msec.”.

  The second map shown in FIG. 5 is a map showing the relationship between the vehicle body speed VS of the vehicle and a first gain A described later. As shown in FIG. 5, the first gain A is set to increase as the vehicle body speed VS of the vehicle increases. In the present embodiment, the vehicle speeds of the host vehicle and the preceding vehicle are assumed to be equal, and the vehicle body speed of the host vehicle is set to the vehicle body speed VS.

  The third map shown in FIG. 6 is a map showing the relationship between the operation cycle FS of the wiper 18 and a second gain B described later. As shown in FIG. 6, the second gain B is set to increase as the operation cycle FS of the wiper 18 is shorter.

  Here, as shown in FIG. 7, a position P2 (hereinafter, referred to as “first position”) where water on the road surface is landed on the road surface from a position P1 (hereinafter, referred to as “first position”) where the water on the road C2 is wound up by the rear wheel 60. The distance to the “second position”) is defined as a distance (scattering distance) Lw at which mist-like moisture flies. In addition, the time for the mist-like moisture to reach from the first position P1 to the second position P2 is defined as the scattering time. The travel distance traveled by the host vehicle C1 during the scattering time is defined as a travel distance Lv during the scattering. Then, when the inter-vehicle distance Lp is less than or equal to the sum of the distance Lw at which mist-like moisture flies and the travel distance Lv at the time of scattering (that is, when Lp ≦ Lw + Lv), the front wheels FR and FL of the host vehicle C1 and the front wheel FR , FL, the mist-like water wound up by the preceding vehicle C2 is easily wetted. On the other hand, when the inter-vehicle distance Lp is longer than the sum of the distance Lw that the mist-like moisture flies and the travel distance Lv during scattering (that is, when Lp> Lw + Lv), the front wheels FR and FL of the host vehicle C1 and the The disc brake devices 17 corresponding to the front wheels FR and FL are unlikely to be covered with mist-like water wound up by the front traveling vehicle C2. Therefore, it is desirable to estimate the actual growth amount of the moisture film per unit time on the sliding contact surfaces 50a and 50b of the brake rotor 50 from the relationship among the distance Lw that the moisture flies, the travel distance Lv during the scattering, and the inter-vehicle distance Lp.

  By the way, the distance Lw that the mist-like water flies becomes longer because the rotational speed of the rear wheel 60 becomes faster as the vehicle speed of the front traveling vehicle C2 is faster. Further, in each disc brake device 17 corresponding to each wheel FR, FL, RR, RL of the own vehicle C1, the rotational speed of each wheel FR, FL, RR, RL increases as the vehicle body speed of the own vehicle C1 increases. Therefore, the amount of water increases. Furthermore, each disc brake device 17 has a greater amount of water as the amount of precipitation on the vehicle C1 increases. In general, the driver of the vehicle sets the operation cycle FS of the wiper 18 to a shorter cycle as the amount of precipitation on the vehicle C1 increases.

  Therefore, in the present embodiment, mist-like moisture is emitted when the vehicle body speeds VS of the host vehicle C1 and the preceding vehicle C2 are “50 km / h” and the operation cycle of the wiper 18 is the long cycle L. The distance Lw and the flying travel distance Lv are acquired by experiments, simulations, and the like. The inter-vehicle distance threshold value Lpth is set in advance to the sum of the distance Lw that the mist-like moisture flies when the vehicle body speed VS is “50 km / h” and the traveling distance Lv during the scattering, or a value close to the sum. The second map is set so that the first gain A is “1” when the vehicle body speed VS of the host vehicle C1 is “50 km / h”. The third map is set such that the second gain B is “1” when the operation cycle of the wiper 18 is the long cycle L. For example, the inter-vehicle distance Lp between the host vehicle C1 and the preceding vehicle C2 is equal to the inter-vehicle distance threshold Lpth, the body speed VS of the host vehicle C1 is “100 km / h”, and the operation cycle of the wiper 18 is a short cycle H If so, the unit growth amount ΔWl is set to the second growth amount ΔWl2 based on the first map. The first gain A is set to a first value A1 (a value larger than “1”, for example, “1.5”) based on the second map, and the second gain B is set to the third value A value corresponding to the short period H based on the map (a value larger than “1”, for example, “2”). The actual unit growth amount (hereinafter referred to as “actual growth amount”) ΔW under these conditions is multiplied by the gains A and B together with the unit growth amount ΔWl set based on the first map. (See FIG. 8).

  Next, a precipitation countermeasure processing routine for continuing to provide suitable braking force to the wheels FR, FL, RR, and RL among various control processes executed by the ECU 16 of the present embodiment will be described based on the flowchart shown in FIG. To do.

  Now, the ECU 16 executes a precipitation countermeasure processing routine at predetermined intervals (for example, “6 msec.”) Set in advance. In this precipitation countermeasure processing routine, the ECU 16 determines whether or not it is raining based on the detection signal from the wiper operation unit 19 (step S10). Specifically, when the wiper operation unit 19 is set to “OFF”, the ECU 16 determines that it is not raining, while the wiper operation unit 19 is any of “L”, “M”, and “H”. If it is set to, it is determined that it is raining. Therefore, in the present embodiment, the ECU 16 also functions as a situation determination unit that determines whether or not a moisture film can be formed on the sliding contact surfaces 50 a and 50 b of each brake rotor 50. Step S10 corresponds to a situation determination step.

  If the determination result of step S10 is negative, the ECU 16 proceeds to step S20 described later. On the other hand, when the determination result of step S10 is affirmative, that is, when it is raining, the ECU 16 causes all wheels FR, FL, and so on by brake operation and braking control (for example, traction control and cruise control) by the driver. It is determined whether braking force is applied to RR and RL (step S11). If the determination result is affirmative, the ECU 16 proceeds to step S20, which will be described later. The state in which the braking force is applied to all the wheels FR, FL, RR, RL means that the brake pads 51 are applied to the sliding contact surfaces 50a, 50b of the brake rotor 50 in the disc brake device 17 for each of the wheels FR, FL, RR, RL. , 52 are in sliding contact with each other. In such a state, even if moisture adheres to the sliding contact surfaces 50 a and 50 b of the brake rotor 50, the moisture is caused by friction generated between the brake rotor 50 and the brake pads 51 and 52. They are removed from the sliding surfaces 50a and 50b, respectively.

  On the other hand, if the determination result in step S11 is negative, the ECU 16 does not apply braking force to at least one of the wheels FR, FL, RR, RL, and thus the wheels FR, FL, Based on the detection signals of the wheel speed sensors SE1 to SE4 of the RR and RL, the wheel speed VW of each wheel FR, FL, RR, RL is calculated (step S12). Subsequently, the ECU 16 calculates the vehicle body speed VS using the wheel speed VW of at least one of the wheel speeds VW of the wheels FR, FL, RR, RL calculated in step S12 (step S13). . Therefore, in this embodiment, the ECU 16 also functions as a vehicle body speed acquisition unit. Subsequently, the ECU 16 specifies which of the long cycle L, the middle cycle M, and the short cycle H the operation cycle FS of the wiper 18 is based on the detection signal from the wiper operation unit 19 (step S14). Therefore, in the present embodiment, the ECU 16 also functions as precipitation amount acquisition means for acquiring the operation cycle FS of the wiper 18 in order to estimate the precipitation amount for the vehicle during precipitation.

  Then, ECU16 acquires the information regarding the inter-vehicle distance Lp transmitted from the inter-vehicle distance measuring device ACC (step S15). Therefore, in this embodiment, the ECU 16 also functions as an inter-vehicle distance acquisition unit that acquires the inter-vehicle distance Lp between the host vehicle C1 and the preceding vehicle C2. Step S15 corresponds to an inter-vehicle distance acquisition step. Then, the ECU 16 estimates the actual growth amount ΔW corresponding to the vehicle body speed VS, the operation cycle FS, and the inter-vehicle distance Lp acquired in steps S13, S14, and S15 (step S16).

  Specifically, the ECU 16 assigns the inter-vehicle distance Lp acquired in step S15 to the first map shown in FIG. 4, and sets a unit growth amount ΔWl corresponding to the current inter-vehicle distance Lp. Subsequently, the ECU 16 assigns the vehicle body speed VS calculated in step S13 to the second map shown in FIG. 5, sets the first gain A corresponding to the current vehicle body speed VS, and calculates it in step S14. The operation cycle FS is substituted into the third map shown in FIG. 6, and the second gain B corresponding to the current operation cycle FS is set. Then, the ECU 16 multiplies the unit growth amount ΔWl by the gains A and B, and sets the multiplication result as the actual growth amount ΔW. Therefore, in the present embodiment, the ECU 16 also functions as unit increase amount estimation means for estimating the actual growth amount ΔW of the moisture film in a predetermined cycle (that is, the amount of increase in moisture in the predetermined cycle).

  Subsequently, the ECU 16 determines the moisture film thickness (hereinafter referred to as “moisture film thickness”) W on the sliding contact surfaces 50a and 50b of the brake rotor 50 based on the actual growth amount ΔW estimated in step S16, that is, the brake rotor. The liquid amount of the liquid existing between 50 and the brake pads 51 and 52 is updated (step S17). Specifically, the ECU 16 adds the actual growth amount ΔW estimated in step S16 to the moisture film thickness W before the update, and sets the addition result as the current moisture film thickness W. Therefore, in the present embodiment, the ECU 16 also functions as a liquid amount calculation unit that calculates the moisture film thickness W by integrating the actual growth amount ΔW for each predetermined period. In the present embodiment, the moisture film thickness W of the brake rotor 50 having the thickest moisture film thickness among the brake rotors 50 of the wheels FR, FL, RR, and RL is estimated.

  Then, the ECU 16 determines whether or not the water film thickness W calculated in step S17 is equal to or greater than a film thickness threshold value KW as a preset liquid amount threshold value (step S18). When the amount of moisture (moisture amount) existing between the brake rotor 50 and the brake pads 51 and 52 is too large, the braking force having an appropriate magnitude according to the brake operation by the driver is caused by the influence of the moisture. There is a possibility that FR, FL, RR, RL may not be granted. That is, the braking distance of the vehicle may be increased. Therefore, in the present embodiment, when the moisture film thickness W is equal to or greater than the film thickness threshold value KW, it is determined that the amount of moisture existing between the brake rotor 50 and the brake pads 51 and 52 is excessive. If the determination result in step S18 is negative (W <KW), the ECU 16 determines that the water film thickness W of the brake rotor 50 has not grown to a film thickness that affects the braking distance of the vehicle. Then, the precipitation countermeasure processing routine is temporarily terminated.

  On the other hand, if the determination result in step S18 is affirmative (W ≧ KW), the ECU 16 determines that the moisture film thickness W of the brake rotor 50 has grown to a film thickness that affects the braking distance of the vehicle, Moisture removal control (liquid removal control) for removing moisture present between the brake rotor 50 and the brake pads 51 and 52 is executed (step S19). Specifically, the ECU 16 operates the pump 35 for a preset control time (for example, 2 seconds). Then, since the orifice is formed in the proportional differential pressure valve 27 even in the non-operating state, the brake fluid flows into the wheel cylinders 24 and 25 based on the operation of the pump 35. Therefore, a pressure difference is generated between the master cylinder 20 and the wheel cylinders 24 and 25, and the brake pads 51 and 52 relatively approach the sliding contact surfaces 50a and 50b of the brake rotor 50, respectively. As a result, the brake pads 51 and 52 are slidably contacted with the brake rotor 50 such that a braking force is applied to the wheels FR, FL, RR, and RL so that the driver does not notice that the braking control is being performed. 50a and 50b are in sliding contact. Therefore, in this embodiment, ECU16 functions also as a control means. Step S19 corresponds to an execution step. Then, when the control time has elapsed since the start of moisture removal control, the ECU 16 stops the pump 35, and then proceeds to the next step S20.

  In step S20, the ECU 16 resets the moisture film thickness W to “0 (zero)”. That is, in step S20, when it is not in the rain or when braking force is applied to all the wheels FR, FL, RR, RL, moisture is present between the brake rotor 50 and the brake pads 51, 52. Judged not to exist. Thereafter, the ECU 16 once terminates the precipitation countermeasure processing routine.

  Next, the action of the braking device 15 during precipitation will be described with reference to FIGS. Note that the inter-vehicle distance Lp between the host vehicle C1 and the preceding vehicle C2 is constant during the cycle interval of the control process shown in FIG. In FIG. 9, the solid line indicates the vehicle state at the initial time point t0 when the moisture at the first position P1 is rolled up, and the broken line indicates that the mist-like moisture rolled up from the first position P1 is at the second position P2. It shows the vehicle state at the landing time t1 when landing on the road.

  When the vehicle travels during precipitation, water droplets bounced off the road surface and mist-like water that bounces off the rotating front wheels FR, FL enter the disc brake device 17 of each wheel FR, FL, RR, RL. come. That is, in each disc brake device 17, the amount of moisture interposed between the brake rotor 50 and the brake pads 51 and 52 gradually increases. Further, when the front traveling vehicle C2 is present in front of the host vehicle C1, the mist-like moisture is directed backward (that is, the host vehicle C1) from the front traveling vehicle C2 by the rotation of the rear wheels 60 thereof. Rolled up. At this time, the distance Lw that flies during the scattering time from when the mist-like water rolled up by the preceding vehicle C2 toward the own vehicle C1 starts to land on the road surface and the scattering of the own vehicle C1 during the scattering time. Assume that the sum of the hourly travel distance Lv is smaller than the inter-vehicle distance Lp between the own vehicle C1 and the preceding vehicle C2. Then, mist-like water wound up by the rear wheel 60 of the front traveling vehicle C2 hardly adheres to the front wheels FR and FL of the own vehicle C1 and the disc brake devices 17 for the front wheels FR and FL (see FIG. 7). ). This is because the amount of mist-like water adhering to each disc brake device 17 is determined by the distance Lw flying from the preceding vehicle C2 toward the host vehicle during the scattering time and the traveling distance of the host vehicle C1 during the scattering time. This is because the sum of Lv depends on whether or not the distance Lp between the preceding vehicle C2 and the host vehicle C1 exceeds the distance Lp at the time when the mist-like water starts to scatter.

  The vehicle body speed VS of the host vehicle C1 is increased, and as shown in FIG. 9, the mist-like water wound up toward the host vehicle C1 by the preceding vehicle C2 is moved from the first position P1 (initial time t0) to the second position. The distance Lw that the mist-like moisture flies during the scattering time Th (= t1-t0) until reaching P2 (landing time t1) and the traveling distance when the host vehicle C1 travels during the scattering time Th It is assumed that the sum (= Lw + Lv) with Lv (= VS · Th) is larger than the inter-vehicle distance Lp between the host vehicle C1 and the preceding vehicle C2. Note that the front traveling vehicle C2 travels in the traveling direction during the scattering time Th. Then, the front wheels FR and FL of the host vehicle C1 and the respective disc brake devices 17 for the front wheels FR and FL are wetted by a part of the mist-like moisture wound up by the rear wheel 60 of the front traveling vehicle C2. As a result, in each disk brake device 17, the amount of moisture intervening between the brake rotor 50 and the brake pads 51, 52 is that the mist-like water wound up by the rear wheel 60 of the preceding vehicle C2 is braked. More than the case where it hardly enters between the rotor 50 and the brake pads 51 and 52. Therefore, the actual growth amount ΔW of the moisture film on the sliding contact surfaces 50a and 50b of the brake rotor 50 for the front wheels FR and FL is such that the vehicle body speed VS is high and the preceding vehicle C2 rolls up toward the own vehicle C1. Due to the large amount of water applied to the disc brake device 17 due to the amount of water (that is, scattered water), the amount of precipitation increases even if it does not change.

  As shown in FIG. 10, when the inter-vehicle distance Lp between the host vehicle C1 and the preceding vehicle C2 becomes shorter, the host vehicle C1 out of the mist-like water wound up by the rear wheel 60 of the preceding vehicle C2. The amount of moisture adhering to the front wheels FR, FL and the respective disc brake devices 17 for the front wheels FR, FL increases. Then, when the water film thickness W of the water film on the sliding contact surfaces 50a, 50b of the brake rotor 50 for the front wheels FR, FL exceeds the film pressure threshold value KW, the water removal control is performed for each wheel FR, FL, RR, RL. Is executed.

  Then, the brake pads 51 and 52 are brought into sliding contact with the sliding contact surfaces 50a and 50b of the brake rotor 50 of the wheels FR, FL, RR, and RL, respectively. As a result, the moisture film on the sliding contact surfaces 50 a and 50 b of the brake rotor 50 is removed by the frictional force between the brake rotor 50 and the brake pads 51 and 52. Moreover, since the braking force applied to each wheel FR, FL, RR, RL at this time is very small, the vehicle driver is hardly noticed by the vehicle driver. After such moisture removal control is completed, an appropriate magnitude of braking force is applied to each of the wheels FR, FL, RR, and RL during the brake operation of the driver and the braking control executed by the ECU 16.

Therefore, in this embodiment, the following effects can be obtained.
(1) Generally, in a situation where moisture can enter between the brake rotor 50 and the brake pads 51 and 52, a large amount of mist-like moisture is wound up from the rear wheel 60 of the front traveling vehicle C2. A part of such mist-like liquid enters between the brake rotor 50 and the brake pads 51 and 52 of the host vehicle C1. Moreover, the degree of increase in the amount of moisture existing between the brake rotor 50 and the brake pads 51 and 52 increases as the inter-vehicle distance Lp between the preceding vehicle C2 and the host vehicle C1 is shorter. Therefore, in the present embodiment, when the vehicle travels during precipitation, the execution timing of the moisture removal control for removing the moisture film on the sliding contact surfaces 50a and 50b of the brake rotor 50 is determined by the own vehicle C1 and the preceding vehicle C2. As the inter-vehicle distance Lp becomes shorter, the earlier timing is set. Therefore, moisture removal control can be executed at an appropriate timing considering the inter-vehicle distance Lp between the host vehicle C1 and the preceding vehicle C2.

  (2) In addition, the moisture removal control is executed at a timing that considers not only the inter-vehicle distance Lp between the host vehicle C1 and the preceding vehicle C2, but also the vehicle body speed VS of the host vehicle C1. Therefore, moisture removal control can be executed at a more appropriate timing.

  (3) Furthermore, the moisture removal control is executed at a timing that considers not only the inter-vehicle distance Lp between the host vehicle C1 and the preceding vehicle C2 and the vehicle body speed VS of the host vehicle C1, but also the operation cycle FS of the wiper 18. . Therefore, moisture removal control can be executed at a more appropriate timing.

  (4) The actual growth amount ΔW of the moisture film on the sliding contact surfaces 50a and 50b of the brake rotor 50 in a predetermined cycle preset as an execution cycle of the precipitation countermeasure processing routine is the inter-vehicle distance between the own vehicle C1 and the preceding vehicle C2. It is estimated that Lp increases as the length is shorter. Then, the actual growth amount ΔW estimated for each predetermined cycle is integrated, and the integration result is used as the moisture film thickness W of the moisture film on the sliding contact surfaces 50a, 50b of the brake rotor 50. When the moisture film thickness W calculated in this way becomes equal to or greater than a preset liquid amount threshold value KW, moisture removal control is executed. As a result, moisture films on the sliding contact surfaces 50a and 50b of the brake rotor 50 are removed, so that an appropriate braking force can be applied to the wheels FR, FL, RR, and RL during subsequent braking operation and braking control.

  (5) In the present embodiment, when the moisture film thickness W of the brake rotor 50 having the largest moisture film thickness W among the brake rotors 50 of the wheels FR, FL, RR, and RL is equal to or greater than the film pressure threshold value KW, Moisture removal control is executed. Therefore, an increase in the control load of the ECU 16 can be suppressed as compared with the case where the water removal control is individually executed for each of the wheels FR, FL, RR, and RL.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. The second embodiment is different from the first embodiment in the method for setting the execution timing of the moisture removal control. Therefore, in the following description, parts different from those of the first embodiment will be mainly described, and the same or corresponding member configurations as those of the first embodiment are denoted by the same reference numerals, and redundant description will be omitted. Shall.

  As shown in FIG. 11, the ROM 56 of the ECU 16 of the present embodiment stores in advance a fourth map showing the relationship between the inter-vehicle distance Lp between the host vehicle C1 and the preceding vehicle C2 and the temporary time threshold value KT_K. The temporary time threshold value KT_K is set to the first time threshold value T1 when the inter-vehicle distance Lp exceeds the preset inter-vehicle distance threshold value Lpth. The temporary time threshold KT_K is a second time shorter than the first time threshold T1 when the inter-vehicle distance Lp is equal to or less than the inter-vehicle distance threshold Lpth and exceeds half of the inter-vehicle distance threshold Lpth (= Lpth / 2). The time threshold is T2. Further, the temporary time threshold value KT_K is set to a third time threshold value T3 that is shorter than the second time threshold value T2 when the inter-vehicle distance Lp is equal to or less than half the inter-vehicle distance threshold value Lpth (= Lpth / 2). That is, the temporary time threshold value KT_K set based on the inter-vehicle distance Lp is set to be shorter as the inter-vehicle distance Lp is shorter.

  The temporary time threshold value KT_K is determined when the vehicle speed VS of the host vehicle C1 is “50 km / h” and the operation cycle FS of the wiper 18 is the long cycle L. This is an elapsed time threshold set according to the inter-vehicle distance Lp. The time thresholds T1 to T3 are the moisture films on the sliding contact surfaces 50a and 50b of the brake rotor 50 for the front wheels FR and FL when the vehicle travels in a state where the inter-vehicle distance Lp corresponding to the threshold is maintained. The time when the thickness W is estimated to be equal to or greater than the film thickness threshold KW is set.

  Next, the precipitation countermeasure processing routine executed by the ECU 16 of the present embodiment will be described based on the flowchart shown in FIG. 12 with a focus on differences from the precipitation countermeasure processing routine of the first embodiment. In FIG. 12, only the portions of the precipitation countermeasure processing routine that are different from the precipitation countermeasure processing routine of the first embodiment are shown.

  Now, the ECU 16 executes a precipitation countermeasure processing routine at predetermined intervals set in advance. In this precipitation countermeasure process routine, the ECU 16 sequentially executes the processes corresponding to steps S10 to S15. Subsequently, the ECU 16 sets the elapsed time threshold KT according to the current inter-vehicle distance Lp between the host vehicle C1 and the preceding vehicle C2, the current vehicle body speed VS of the host vehicle C1, and the current operation cycle FS of the wiper 18. Set (step S30). Specifically, the ECU 16 substitutes the inter-vehicle distance Lp acquired in step S15 into the fourth map shown in FIG. 11, and sets a temporary time threshold value KT_K corresponding to the inter-vehicle distance Lp. Subsequently, the ECU 16 substitutes the vehicle body speed VS calculated in step S13 in the second map shown in FIG. 5, sets a first gain A corresponding to the current vehicle body speed VS, and in step S14. The calculated operation cycle FS is substituted into the third map shown in FIG. 6, and the second gain B corresponding to the current operation cycle FS is set. Then, the ECU 16 divides both the gains A and B with respect to the temporary time threshold value KT_K, and sets the division result as an elapsed time threshold value KT. Therefore, in this embodiment, the ECU 16 also functions as a threshold setting unit.

  Subsequently, the ECU 16 determines whether or not the elapsed time T after the braking force is applied to all the wheels FR, FL, RR, and RL is equal to or greater than the elapsed time threshold value KT set in step S30. (Step S31). When this determination time is negative (T <KT), the ECU 16 determines that the water film thickness W of the brake rotor 50 has not grown to a film thickness that affects the braking distance of the vehicle, and the elapsed time T is updated (step S32). Therefore, in this embodiment, ECU16 functions also as an elapsed time measurement means. Thereafter, the ECU 16 once terminates the precipitation countermeasure processing routine.

  On the other hand, if the determination result in step S31 is affirmative (T ≧ KT), the ECU 16 determines that the moisture film thickness W of the brake rotor 50 has grown to a film thickness that affects the braking distance of the vehicle, Moisture removal control, which is the same process as step S19, is executed (step S33). When the ECU 16 terminates the moisture removal control, the elapsed time T is reset to “0 (zero)” (step S34), and then the precipitation countermeasure processing routine is temporarily terminated.

Therefore, in this embodiment, in addition to the effects (1) to (3) in the first embodiment, the following effects can be obtained.
(6) The elapsed time threshold value KT for determining the execution timing of the moisture removal control is set so as to decrease as the inter-vehicle distance Lp between the host vehicle C1 and the preceding vehicle C2 decreases. Then, when the elapsed time T after the braking force is applied to all the wheels FR, FL, RR, RL becomes equal to or greater than the elapsed time threshold value KT, the moisture removal control is executed. As a result, moisture films on the sliding contact surfaces 50a and 50b of the brake rotor 50 are removed, so that an appropriate braking force can be applied to the wheels FR, FL, RR, and RL during subsequent braking operation and braking control.

Each embodiment may be changed to another embodiment as described below.
In each embodiment, in the moisture removal control, not only the pump 35 but also the proportional differential pressure valve 27 may be operated. In this case, since the pressure difference between the master cylinder pressure and the wheel cylinder pressure becomes large, a large braking force is applied to each wheel FR, FL, RR, RL as compared with the above embodiments. become. Therefore, moisture can be reliably removed from the sliding contact surfaces 50a, 50b of each brake rotor 50.

  In each embodiment, the moisture film thickness W is estimated for each brake rotor 50, and the moisture removal control is performed so that the brake pads 51 and 52 are brought into sliding contact with the brake rotor 50 whose moisture film thickness W is equal to or greater than the film thickness threshold KW. May be performed. For example, as shown in FIG. 13, when the preceding vehicle C2 is traveling on a lane different from the lane on which the own vehicle C1 is traveling (in this case, the lane on the right side), the front traveling vehicle C2 of the front wheels FR, FL The mist-like water wound up by the forward vehicle C2 adheres to the near right front wheel FR and the disc brake device 17 corresponding to the right front wheel FR. On the other hand, the mist-like water wound up by the front traveling vehicle C2 hardly adheres to the left front wheel FL and the disc brake device 17 corresponding to the left front wheel FL.

  In this case, the inter-vehicle distance measuring device ACC or the like detects the position of the front vehicle C2 in the left-right direction with respect to the host vehicle C1, and the execution timing of moisture removal control for the right front wheel FR on the side close to the front vehicle C2 is determined as the left front wheel FL. It is desirable to make it earlier than the execution timing of the moisture removal control for. If comprised in this way, water | moisture-content removal control can be performed at an appropriate timing for every wheel FR, FL, RR, RL.

  -In each embodiment, when it becomes an execution timing in the middle of a vehicle turning, you may make it perform water removal control after the turn is complete | finished. If comprised in this way, it can avoid giving braking force to wheel FR, FL, RR, RL irrespective of a driver | operator's will at the time of vehicle turning, and, as a result, the behavior stability of the vehicle turning can be ensured.

  In each embodiment, the vehicle body speed VS of the vehicle may not be derived from each wheel speed VW of the host vehicle C1, but may be derived based on other parameters (for example, acceleration of the host vehicle C1). Further, the vehicle body speed VS may be substituted by the vehicle body speed of the preceding vehicle C2, or may be derived using vehicle body speed information used in various infrastructures such as traffic jam information.

  In the first embodiment, the actual growth amount ΔW is estimated based on the inter-vehicle distance Lp between the host vehicle C1 and the preceding vehicle C2 and the vehicle body speed VS of the host vehicle C1 regardless of the operation cycle FS of the wiper 18. It may be a value obtained. In the second embodiment, the elapsed time threshold value KT is based on the inter-vehicle distance Lp between the host vehicle C1 and the preceding vehicle C2 and the vehicle body speed VS of the host vehicle C1 regardless of the operation cycle FS of the wiper 18. It may be an estimated value.

  In the first embodiment, the actual growth amount ΔW is estimated based on the inter-vehicle distance Lp between the host vehicle C1 and the preceding vehicle C2 and the operation cycle FS of the wiper 18 regardless of the vehicle body speed VS of the host vehicle C1. It may be a value obtained. In the second embodiment, the elapsed time threshold KT is based on the inter-vehicle distance Lp between the host vehicle C1 and the preceding vehicle C2 and the operation cycle FS of the wiper 18 regardless of the vehicle body speed VS of the host vehicle C1. It may be an estimated value.

  In the first embodiment, the actual growth amount ΔW may be a value estimated based only on the inter-vehicle distance Lp between the host vehicle C1 and the preceding vehicle C2. In the second embodiment, the elapsed time threshold KT may be a value estimated based only on the inter-vehicle distance Lp between the host vehicle C1 and the preceding vehicle C2.

  In each embodiment, a rain sensor for recognizing rainy weather may be provided in the vehicle. In this case, in step S10, it may be determined whether or not it is raining based on the detection signal from the rain sensor.

  When a rain sensor is provided in a vehicle, the precipitation is acquired based on the type of detection signal output by the rain sensor according to the precipitation and stored in the RAM 57, or the output frequency of the detection signal from the rain sensor is set. The amount of precipitation is acquired based on the storage result. Then, the ECU 16 estimates the actual growth amount ΔW of the moisture film in a predetermined cycle from the acquired precipitation amount, the vehicle body speed VS at the time of precipitation, and the inter-vehicle distance Lp between the host vehicle C1 and the preceding vehicle C2. . In this case, ECU16 which acquires precipitation based on the detection signal output from a rain sensor functions also as precipitation acquisition means.

In each embodiment, the execution time of the moisture removal control may be a time other than 2 seconds (for example, 3 seconds) as long as it is between 1 and 3 seconds.
In each embodiment, it is desirable that the moisture removal control is executed when an accelerator pedal (not shown) is operated by the driver. When configured in this way, it is possible to reduce the possibility that the driver will notice the execution of moisture removal control.

  Further, even when a braking force is applied to the wheels FR, FL, RR, and RL (that is, even when the brake pads 51 and 52 are slidably contacted with the brake rotor 50), the magnitude of the braking force and the time for applying the braking force Depending on the length, the water adhering to the brake rotor 50 may not be completely removed. Therefore, when a braking force is applied to the wheels FR, FL, RR, RL, the subtraction amount is set to a larger value as the braking force is increased and the time for applying the braking force is longer. The subtraction amount may be subtracted from the moisture film thickness W in the brake rotor 50, and the subtraction result may be the current moisture film thickness W.

  In each embodiment, a drum brake device may be mounted on the vehicle instead of the disc brake device 17. In this case, the ECU 16 includes moisture existing between a brake drum as a first braking member that rotates together with the wheels FR, FL, RR, and RL and a shoe as a second braking member that can slide on the brake drum. Estimate the amount of water. And ECU16 performs moisture removal control, when the estimated water content is more than the preset water content threshold value (liquid amount threshold value).

  16: Control means, situation determination means, inter-vehicle distance acquisition means, vehicle body speed acquisition means, precipitation amount acquisition means, unit increase amount estimation means, liquid amount calculation means, elapsed time measurement means, ECU as threshold setting means, 50. Brake rotor as one braking member, 51, 52 ... Brake pad as second braking member, C1 ... Own vehicle, C2 ... Previous vehicle, FR, FL, RR, RL ... Wheel, KT ... Elapsed time threshold, KW ... Film thickness threshold as a liquid amount threshold, Lp: distance between vehicles, Lv: travel distance at the time of scattering, Lw: distance of water to fly as a scattering distance, P1: first position, P2: second position, T: elapsed time, VS … Body speed, W… water film thickness, ΔW… actual growth.

Claims (7)

A first braking member (50) that rotates together with the wheels (FR, FL, RR, RL), and the wheels (FR, FL, RR, RL) by contacting the rotating first braking member (50). Mounted on a vehicle having a second braking member (51, 52) capable of applying a braking force to
When liquid is present between the brake members (50, 51, 52), the second brake member (51, 52) is brought into contact with the first brake member (50) in order to remove the liquid. In the vehicle movement support device including the control means (16, S19) for executing the liquid removal control,
Situation determination means (16, S10) for determining whether or not the liquid can enter between the braking members (50, 51, 52);
An inter-vehicle distance acquisition means (16, S15) for acquiring an inter-vehicle distance (Lp) with the preceding vehicle (C2) traveling forward;
The situation in which liquid can enter between the braking members (50, 51, 52) determined by the condition determination means (16, S10) is a condition in which the road surface is wet during or after precipitation. ,
The control means (16, S19) is configured so that the situation determination means (16, S10) determines that the liquid can enter between the braking members (50, 51, 52). The vehicle movement support device is characterized in that the liquid removal control is executed at an earlier timing as the inter-vehicle distance (Lp) acquired by the distance acquisition means (16, S15) is shorter. Vehicle body speed acquisition means (16, S13) for acquiring the vehicle body speed (VS) of the vehicle;
When the control means (16, S19) determines that the liquid can enter between the brake members (50, 51, 52) by the situation determination means (16, S10), the vehicle body The vehicle movement support device according to claim 1, wherein the liquid removal control is executed at an earlier timing as the vehicle body speed (VS) acquired by the speed acquisition means (16, S13) is faster. It further comprises precipitation amount acquisition means (16, S14) for acquiring precipitation amount for the vehicle at the time of precipitation,
When the control means (16, S19) determines that the liquid can enter between the braking members (50, 51, 52) by the situation determination means (16, S10), the precipitation means The vehicle movement support device according to claim 1 or 2, wherein the liquid removal control is executed at an earlier timing as the amount of precipitation acquired by the amount acquisition means (16, S14) increases. The control means (16, S19)
In the case where it is determined by the situation determination means (16, S10) that the liquid can enter between the braking members (50, 51, 52),
Scattering distance from the first position (P1) where the liquid is rolled up toward the own vehicle (C1) by the preceding vehicle (C2) to the second position (P2) where the rolled up liquid lands on the road surface (Lw) and the sum (Lw + Lv) of the travel distance (Lv) of the vehicle (C1) from when the liquid is rolled up by the preceding vehicle (C2) until it lands on the road surface, The liquid removal control is executed at an earlier timing when the sum (Lw + Lv) is less than the inter-vehicle distance (Lp) when the inter-vehicle distance (Lp) is greater than or equal to the inter-vehicle distance (Lp) acquired by the acquisition means (16, S15). The vehicle motion support device according to claim 2 or 3, wherein When it is determined by the situation determination means (16, S10) that the liquid can enter between the braking members (50, 51, 52), the braking members (in a predetermined cycle set in advance) 50, 51, 52) The unit increase which estimates the increase amount (ΔW) of the liquid existing so as to increase as the inter-vehicle distance (Lp) acquired by the inter-vehicle distance acquisition means (16, S15) decreases. Quantity estimation means (16, S16);
The amount of increase (ΔW) of the liquid estimated by the unit increase amount estimation means (16, S16) is integrated every predetermined period, and between the brake members (50, 51, 52) based on the integration result. Liquid amount calculating means (16, S17) for calculating the liquid amount (W) of the liquid existing in
In the control means (16, S19), the liquid amount (W) of the liquid existing between the brake members (50, 51, 52) calculated by the liquid amount calculation means (16, S17) is set in advance. The vehicle movement support device according to any one of claims 1 to 4, wherein the liquid removal control is executed when the liquid amount threshold (KW) is equal to or greater than the determined liquid amount threshold value. An elapsed time measuring means (16, S32) for measuring an elapsed time (T) from when the braking force is applied to the wheels (FR, FL, RR, RL);
When it is determined by the situation determination means (16, S10) that the liquid can enter between the braking members (50, 51, 52), the execution timing of the liquid removal control is determined. Threshold value setting means (16, S30) for setting the elapsed time threshold value (KT) to be smaller as the inter-vehicle distance (Lp) acquired by the inter-vehicle distance acquisition means (16, S15) is shorter;
The control means (16, S19) includes an elapsed time threshold (KT) in which the elapsed time (T) measured by the elapsed time measurement means (16, S32) is set by the threshold setting means (16, S30). The vehicle movement support apparatus according to any one of claims 1 to 4, wherein the liquid removal control is executed in the case described above. A first braking member (50) that rotates together with wheels (FR, FL, RR, RL) mounted on the vehicle, and the wheels (FR, FL) by contacting the rotating first braking member (50). , RR, RL) when there is liquid between the second braking member (51, 52) capable of applying a braking force to the first braking member (50), the second braking member (51, 52). In the vehicle movement support method, the execution step (S19) of executing the liquid removal control for removing the liquid by contacting the
A situation determination step (S10) for determining whether or not a liquid can enter between the brake members (50, 51, 52);
An inter-vehicle distance acquisition step (S15) for acquiring an inter-vehicle distance (Lp) with the preceding vehicle (C2) traveling forward;
The situation in which liquid can enter between the braking members (50, 51, 52) determined in the situation determination step (S10) is a situation in which the road surface is wet during or after the precipitation,
In the execution step (S19), when it is determined in the situation determination step (S10) that the liquid can enter between the braking members (50, 51, 52), the inter-vehicle distance acquisition step ( The vehicle movement support method, wherein the liquid removal control is executed at an earlier timing as the inter-vehicle distance (Lp) acquired in S15) is shorter.

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