JP4561541B2 - Vehicle traction control device and vehicle traction control method - Google Patents

Description

  The present invention relates to a traction control device for a vehicle and a traction control method for a vehicle that suppresses drive slip of a drive wheel during traveling of the vehicle.

  In general, when a vehicle is driven, when a passenger depresses an accelerator pedal, driving wheels driven based on driving force from an engine among the wheels (for example, left and right front wheels in the case of a front wheel drive vehicle) are driven. May slip. Such a drive slip impairs the running stability of the vehicle. Therefore, conventionally, a vehicle traction control device and a vehicle traction control method for suppressing the drive slip of the drive wheel have been widely known. That is, in such a traction control device for a vehicle, when it is detected that the drive wheel has slipped, the braking force applied to the drive wheel in which the drive slip has occurred is increased by increasing the brake fluid pressure in the fluid pressure circuit. Increasing. As the braking force increases, the rotational speed of the drive wheels decreases, and as a result, the occurrence of drive slips during vehicle travel is suppressed.

  By the way, in the process of suppressing the driving slip of the driving wheel as described above, the driving wheel periodically drives and slips, and vibration (and abnormal noise based on the vibration) generated in the driving wheel is transmitted to the passenger compartment and boarding. There was a problem that the person had discomfort. Therefore, recently, in order to solve these problems, for example, a traction control device for a vehicle and a traction control method for a vehicle described in Patent Document 1 have been proposed.

That is, in the traction control device for a vehicle described in Patent Document 1, when the brake hydraulic pressure in the hydraulic pressure circuit increased due to the occurrence of the drive slip of the drive wheel becomes equal to or higher than a predetermined set value, The brake fluid pressure is continuously reduced. Then, by reducing the brake fluid pressure in the fluid pressure circuit in this way, the generation of vibrations of the drive wheels that cause the passenger to feel uncomfortable is suppressed.
Japanese Patent Laid-Open No. 5-221301 (paragraph numbers [0009], [0010])

  By the way, in the traction control device for a vehicle described in Patent Document 1, a wheel speed (or slip ratio) for each drive wheel is detected based on a signal from a wheel speed sensor of each drive wheel, and the detected wheel speed (or slip) is detected. The brake fluid pressure is changed in response to the change in rate. In this case, there is a time for detecting (calculating) the wheel speed (or slip ratio) based on a signal from the wheel speed sensor and a time for increasing the brake hydraulic pressure in the hydraulic circuit. . Therefore, due to the existence of such time, as shown in FIG. 10, the hydraulic pressure is actually slightly delayed (for example, about “70 (ms)”) from the drive wheel vibration generation timing (drive slip change timing). The brake fluid pressure in the circuit will change. Therefore, especially at resonance with a short vibration cycle, the drive slip is reduced when the brake fluid pressure in the hydraulic circuit is actually increased, or the drive is driven when the brake fluid pressure is actually reduced. In some cases, the slip may increase, and the vibration of the driving wheel may be promoted.

  The present invention has been made in view of such circumstances, and an object of the present invention is to generate a drive wheel that is generated when the brake fluid pressure is changed in order to suppress a drive slip of the drive wheel during traveling of the vehicle. An object of the present invention is to provide a traction control device for a vehicle and a traction control method for a vehicle that can suitably suppress the vibration of the vehicle.

In order to achieve the above-mentioned object, when driving slip of the driving wheel is detected during traveling of the vehicle, the brake fluid pressure is changed to suppress the driving slip and periodically in the process of suppressing the driving slip of the driving wheel. Traction control device for a vehicle that suppresses drive slip generated in the hydraulic pressure variable means (38, 39, M) for varying the brake hydraulic pressure in the hydraulic pressure circuit (33, 34), and the hydraulic pressure variable means (38, 39, M) Braking means for applying a braking force to the drive wheels (FR, FL) of the vehicle when the brake fluid pressure in the hydraulic circuit (33, 34) is increased based on the drive of (38, 39, M). 36a, 36b), wheel speed detection means (SE5, SE6, 60) for detecting the wheel speed (VW) of the drive wheels (FR, FL), and the drive wheels (FR, FL) during travel of the vehicle. Periodic Vibration detecting means (SE5, SE6, 60) for detecting vibration generated based on dynamic slip (SLP), and vibrations of the drive wheels (FR, FL) detected by the vibration detecting means (SE5, SE6, 60) A vibration pattern specifying means (60) for specifying a vibration pattern (P1, P2, P3, P4) determined in advance based on an aspect, a driving wheel vibrating from among a plurality of driving wheels , and the vibration pattern specifying means ( 60) delay times (Ta, Tb, Tc, Td) for delaying the drive timing of the hydraulic pressure variable means (38, 39, M) according to the vibration pattern (P1, P2, P3, P4) specified by (60). ) For setting a delay time (60) and an elapsed time (T) after the vibration pattern specifying means (60) specifies the vibration pattern (P1, P2, P3, P4). Determining means (60) for determining whether or not the delay time (Ta, Tb, Tc, Td) set by the delay time setting means (60) is greater than or equal to the delay time (Ta, Tb, Tc, Td). If There is affirmative determination, the identified vibration to which the driving wheels (FR, FL) said braking means (36a, 36b) for the by periodically based on the vibration pattern braking force is the specific It is summarized that it is provided with a control means (60) for driving the fluid pressure varying means (38, 39, M) as provided.

  In the above configuration, when the driving wheel vibrates during traveling of the vehicle, a vibration pattern is specified based on the vibration mode, and a delay time for delaying the drive timing of the hydraulic pressure variable means is set according to the vibration pattern. Is done. Here, when increasing the brake fluid pressure in the hydraulic circuit, it takes time for the vibration pattern specifying means to specify the vibration pattern, or it takes time for the brake fluid pressure to actually increase. Or Therefore, by setting a delay time that takes into account each of the above-described times, the brake hydraulic pressure in the hydraulic pressure circuit can be changed without delaying the change of the drive slip. Therefore, it is possible to suitably suppress vibrations of the drive wheels that are generated when the brake fluid pressure is changed in order to suppress drive slip of the drive wheels when the vehicle is traveling.

  According to a second aspect of the present invention, in the vehicle traction control device according to the first aspect, the vibration detection means (SE5, SE6, 60) is detected by the wheel speed detection means (SE5, SE6, 60). The gist is to detect vibration of the drive wheels (FR, FL) by detecting a periodic change in the wheel speed (VW) of the drive wheels (FR, FL).

  In the above configuration, the wheel speed detecting means detects a periodic change in the wheel speed of the driving wheel, thereby detecting the vibration of the driving wheel. Therefore, it is possible to suppress an increase in the number of parts due to separately providing means (for example, a vehicle speed sensor) for detecting the vibration of the drive wheel.

  According to a third aspect of the present invention, in the vehicle traction control device according to the first or second aspect, the vibration pattern storage means stores a plurality of vibration patterns (P1, P2, P3, P4) having different vibration modes. (61), and the vibration pattern specifying means (60) is a vibration pattern (P1) corresponding to the vibration mode of the drive wheels (FR, FL) detected by the vibration detection means (SE5, SE6, 60). , P2, P3, P4) is read from the vibration pattern storage means (61).

  In the above configuration, the vibration pattern is specified by reading out the vibration pattern corresponding to the vibration mode of the driving wheel detected by the vibration detection unit from the vibration pattern storage unit. That is, it is not necessary to perform arithmetic processing using the relational expression in order to specify this vibration pattern. Therefore, it is possible to favorably reduce the processing load of the vibration pattern specifying means.

  According to a fourth aspect of the present invention, in the traction control device for a vehicle according to the first or second aspect, the vibration pattern specifying means (60) is detected by the vibration detection means (SE5, SE6, 60). Based on the vibration mode of the drive wheels (FR, FL), the drive wheels (FR, FL) vibrating from the plurality of drive wheels (FR, FL) are specified, and the specified drive wheels (FR, FL) The gist is to specify the vibration pattern (P1, P2, P3, P4) by calculating the vibration period (T1, T2, T3, T4) of the vibration in (FL).

  In the above configuration, the vibration pattern specifying means specifies the driving wheel vibrating based on the vibration mode of the driving wheel detected by the vibration detecting means, calculates the vibration cycle of the vibration in the driving wheel, and the result The vibration pattern is specified from the above. Therefore, it is not necessary to previously store the vibration pattern in a storage unit such as a ROM. That is, an increase in storage capacity due to storing the vibration pattern in the storage unit can be suppressed.

On the other hand, the invention of claim 5 according to the traction control method for a vehicle, the hydraulic circuit when detecting the traction of the driving wheels definitive during running of the vehicle (FR, FL) (SLP) (33,34) in By suppressing the brake fluid pressure of the vehicle, the vehicle suppresses the drive slip (SLP) of the drive wheels (FR, FL) and also suppresses the drive slip periodically generated in the process of suppressing the drive slip of the drive wheel. In this traction control method, vibration generated based on a periodic drive slip (SLP) of the drive wheels (FR, FL) during traveling of the vehicle is detected, and the detected drive wheels (FR, FL) are detected. drive wheel (FR, FL) based on the vibration mode vibration pattern of a predetermined vibration at (P1, P2, P3, P4 ) and in a plurality of drive wheels Identify the drive wheel that is al vibration, delays the timing of boosted brake hydraulic pressure of the hydraulic circuit (33, 34) in accordance to the particular vibration pattern (P1, P2, P3, P4) After setting the delay time (Ta, Tb, Tc, Td) to be performed, the elapsed time (T) after the vibration pattern (P1, P2, P3, P4) is set is the delay time (Ta, Tb). , Tc, when a Td) above, the identified vibration to which the driving wheels (FR, the liquid to periodically granted based on the vibration pattern of the braking force is the specific for the FL) The gist is that the brake fluid pressure in the pressure circuit (33, 34) is increased.

  With the configuration described above, the same effects as those of the first aspect of the invention can be achieved.

  Hereinafter, an embodiment embodying 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 traction control device 11 according to the present embodiment includes a plurality of (four in the present embodiment) wheels (right front wheel FR, left front wheel FL, right rear wheel RR, and left rear wheel RL). Of these, the front wheels FR and FL are mounted on a vehicle (so-called front wheel drive vehicle) that functions as drive wheels. The traction control device 11 includes a driving force transmission mechanism 13 that transmits a driving force generated by an engine 12 serving as a driving source to front wheels FR and FL, and a front wheel steering mechanism that turns the front wheels FR and FL as steering wheels. 14 and a braking force applying mechanism 15 for applying a braking force to each of the wheels FL, FR, RL, and RR. The traction control device 11 includes an electronic control device (also referred to as “ECU”) 16 for appropriately controlling the mechanisms 13, 14, and 15 according to the traveling state of the vehicle. The engine 12 generates a driving force corresponding to the depression operation of the accelerator pedal 17 by the vehicle occupant.

  The driving force transmission mechanism 13 includes a throttle valve actuator (for example, a DC motor) 20 for controlling the opening degree of a throttle valve 19 that varies the opening cross-sectional area of the intake passage 18 a in the intake pipe 18, and an intake port of the engine 12. A fuel injection device 21 having an injector for injecting fuel is provided in the vicinity (not shown). The driving force transmission mechanism 13 is provided with a transmission 22 connected to the output shaft of the engine 12 and a differential gear 23 that appropriately distributes the driving force transmitted from the transmission 22 and transmits it to the front wheels FL and FR. It has been. Further, the driving force transmission mechanism 13 includes an accelerator opening sensor SE1 for detecting the depression amount (opening) of the accelerator pedal 17, a rotation speed sensor SE2 for detecting the rotation speed of the engine 12, and a throttle valve. A throttle valve opening sensor SE3 for detecting the opening of 19 is provided.

  The front wheel steering mechanism 14 is provided with a steering wheel 24, a steering shaft 25 to which the steering wheel 24 is fixed, and a steering actuator 26 connected to the steering shaft 25. Further, the front wheel steering mechanism 14 is provided with a link mechanism portion 27 including a tie rod that can be moved in the left-right direction of the vehicle by a steering actuator 26 and a link that steers the front wheels FL and FR by the movement of the tie rod. It has been. Further, the front wheel steering mechanism 14 is provided with a steering angle sensor SE4 for detecting the steering angle of the steering wheel 24.

Next, the braking force application mechanism 15 will be described with reference to FIG.
As shown in FIG. 2, the braking force applying mechanism 15 of the present embodiment includes a hydraulic pressure generating device 32 having a master cylinder 30 and a booster 31, and a hydraulic pressure control device having two hydraulic pressure circuits 33 and 34 (FIG. 2). Is shown by a two-dot chain line). The hydraulic circuits 33 and 34 are connected to the hydraulic pressure generator 32 and are connected to wheel cylinders 36a, 36b, 36c, and 36d provided corresponding to the wheels FR, FL, RR, and RL. . That is, the wheel cylinder 36a corresponds to the right front wheel FR, and the wheel cylinder 36b corresponds to the left front wheel FL. Further, the wheel cylinder 36c corresponds to the right rear wheel RR, and the wheel cylinder 36d corresponds to the left rear wheel RL. Therefore, in this embodiment, the wheel cylinders 36a and 36b for the front wheels FR and FL function as braking means for applying a braking force to the drive wheels (front wheels FR and FL) of the vehicle.

  The hydraulic pressure generating device 32 is provided with a brake pedal 37, and the master cylinder 30 and the booster 31 of the hydraulic pressure generating device 32 are driven based on the brake pedal 37 being depressed by a vehicle occupant. It is like that. The master cylinder 30 is provided with two output ports 30a and 30b. The first hydraulic circuit 33 is connected to one of the output ports 30a and 30b, and the other of the output ports 30a and 30b. A second hydraulic circuit 34 is connected to the output port 30b. Further, the hydraulic pressure generating device 32 is provided with a brake switch SW1 that transmits a signal to the electronic control device 16 when the brake pedal 37 is operated.

  The hydraulic pressure control device 35 includes a pump 38 for increasing the brake hydraulic pressure in the first hydraulic pressure circuit 33, a pump 39 for increasing the brake hydraulic pressure in the second hydraulic pressure circuit 34, and each pump. A motor M for driving the motors 38 and 39 at the same time is provided. In addition, reservoirs 40 and 41 for storing brake oil are provided on the hydraulic circuits 33 and 34, and the brake oil in the reservoirs 40 and 41 is supplied to the hydraulic circuit based on driving of the pumps 38 and 39. 33 and 34 are supplied. Furthermore, hydraulic pressure sensors PS1 and PS2 for detecting the brake hydraulic pressure in the master cylinder 30 are provided in the hydraulic pressure circuits 33 and 34, respectively.

  The first hydraulic circuit 33 includes a right front wheel path 33a for the wheel cylinder 36a (for the right front wheel FR) connected to the wheel cylinder 36a corresponding to the right front wheel FR, and a wheel cylinder 36d corresponding to the left rear wheel RL. And a left rear wheel path 33b for the wheel cylinder 36d (for the left rear wheel RL) connected to the. On each of the paths 33a and 33b, normally open solenoid valves 42 and 43 and normally closed solenoid valves 44 and 45 are provided, respectively.

  Similarly, the second hydraulic circuit 34 corresponds to the left front wheel path 34a for the wheel cylinder 36b (for the left front wheel FL) connected to the wheel cylinder 36b corresponding to the left front wheel FL, and the right rear wheel RR. A right rear wheel path 34b for the wheel cylinder 36c (for the right rear wheel RR) connected to the wheel cylinder 36c is formed. On each of the paths 34a and 34b, normally open electromagnetic valves 46 and 47 and normally closed electromagnetic valves 48 and 49 are provided, respectively.

  In addition, a normally open proportional solenoid valve 50 is connected to the master cylinder 30 side of the first hydraulic circuit 33 with respect to the portions branched into the paths 33a and 33b, and in parallel with the proportional solenoid valve 50. A relief valve 51 is connected. The proportional solenoid valve 50 and the relief valve 51 constitute a proportional differential pressure valve 52. The proportional differential pressure valve 52 can generate a hydraulic pressure difference (brake hydraulic pressure difference) on the master cylinder 30 side and the wheel cylinders 36a and 36d side with respect to the proportional differential pressure valve 52 based on control by the electronic control unit 16. Note that the maximum value of the hydraulic pressure difference is a value based on the urging force of the spring 51 a constituting the relief valve 51. The first hydraulic circuit 33 is formed with a branch hydraulic pressure path 33c branched from between the reservoir 40 and the pump 38 toward the master cylinder 30. On the branch hydraulic pressure path 33c, a branch hydraulic pressure path 33c is formed. A normally closed electromagnetic valve 53 is connected.

  Similarly, a normally open proportional solenoid valve 54 is connected to the master cylinder 30 side of the second hydraulic circuit 34 that is branched to the paths 34 a and 34 b, and in parallel with the proportional solenoid valve 54. A relief valve 55 is connected. The proportional solenoid valve 54 and the relief valve 55 constitute a proportional differential pressure valve 56. The proportional differential pressure valve 56 can generate a hydraulic pressure difference (brake hydraulic pressure difference) between the master cylinder 30 side and the wheel cylinders 36b and 36c than the proportional differential pressure valve 56, based on control by the electronic control unit 16. Note that the maximum value of the hydraulic pressure difference is a value based on the urging force of the spring 55a constituting the relief valve 55. Further, the second hydraulic pressure circuit 34 is formed with a branch hydraulic pressure passage 34c branched from between the reservoir 41 and the pump 39 toward the master cylinder 30, and on the branch hydraulic pressure passage 34c. A normally closed electromagnetic valve 57 is connected.

  Here, changes in the brake fluid pressure in the wheel cylinders 36a to 36d when the solenoid coils of the solenoid valves 42 to 49 are in an energized state and in a non-energized state will be described. In the following description, it is assumed that the proportional solenoid valves 50 and 54 are in a closed state and the solenoid valves 53 and 57 on the branch hydraulic pressure paths 33c and 34c are in a closed state.

  First, when all the solenoid coils of the solenoid valves 42 to 49 are in a non-energized state, the normally open solenoid valves 42, 43, 46, 47 remain open and the normally closed solenoid valves 44, 45, 48 and 49 remain closed. Therefore, when the pumps 38 and 39 are driven, the brake oil in the reservoirs 40 and 41 flows into the wheel cylinders 36a to 36d via the paths 33a, 33b, 34a and 34b, and the wheels The brake fluid pressure in the cylinders 36a to 36d will increase.

  On the other hand, when all the solenoid coils of the solenoid valves 42 to 49 are energized, the normally open solenoid valves 42, 43, 46, 47 are closed and the normally closed solenoid valves 44, 45 are closed. , 48, 49 are opened. Therefore, brake oil flows from the wheel cylinders 36a to 36d to the reservoirs 40 and 41 via the paths 33a, 33b, 34a, and 34b, and the brake hydraulic pressure in the wheel cylinders 36a to 36d decreases. Become.

  When only the solenoid coils of the normally open solenoid valves 42, 43, 46, and 47 among the solenoid valves 42 to 49 are energized, all the solenoid valves 42 to 49 are closed. Therefore, the flow of brake oil through each path 33a, 33b, 34a, 34b is restricted. As a result, the brake hydraulic pressure in each wheel cylinder 36a-36d is maintained at its hydraulic pressure level. Therefore, in this embodiment, the pumps 38 and 39 and the motor M function as hydraulic pressure varying means for varying the brake hydraulic pressure in the hydraulic pressure circuits 33 and 34.

  As shown in FIG. 1, the electronic control device 16 is mainly configured by a digital computer including a CPU 60, a ROM 61, and a RAM 62 as control means, and a drive circuit (not shown) for driving each device. ing. The ROM 61 includes a control program for controlling the hydraulic pressure control device 35 (driving the motor M, the electromagnetic valves 42 to 49, 53, 57 and the proportional electromagnetic valves 50, 54), and a plurality of later-described (in this embodiment). 4) vibration patterns P1, P2, P3, P4 (see FIG. 3) and the like are stored. Therefore, in this embodiment, the ROM 61 functions as a vibration pattern storage unit that stores a plurality of vibration patterns P1 to P4 having different vibration modes. The RAM 62 stores various information that can be appropriately rewritten while the traction control device 11 of the vehicle is being driven.

  The input interface (not shown) of the electronic control unit 16 includes the brake switch SW1, hydraulic pressure sensors PS1 and PS2, accelerator opening sensor SE1, rotational speed sensor SE2, throttle valve opening sensor SE3, and steering angle. Sensors SE4 are connected to each other. Further, on the input side interface, wheel speed sensors SE5, SE6, SE7, SE8 for detecting the wheel speed of each wheel FL, FR, RL, RR, lateral acceleration actually acting on the vehicle (so-called “lateral G”). ) And a yaw rate sensor SE10 for detecting the yaw rate actually acting on the vehicle are respectively connected. That is, the CPU 60 receives signals from the brake switch SW1, the hydraulic pressure sensors PS1 and PS2, and the various sensors SE1 to SE10.

  On the other hand, the output side interface (not shown) of the electronic control unit 16 is connected to a motor M for driving the pumps 38, 39, the solenoid valves 42 to 49, 53, 57, and the proportional solenoid valves 50, 54. ing. The CPU 60 individually operates the motor M, the solenoid valves 42 to 49, 53, 57 and the proportional solenoid valves 50, 54 based on the input signals from the switch SW1 and the sensors PS1, PS2, SE1 to SE10. It comes to control.

  Next, vibration patterns relating to the vibrations of the front wheels FR and FL stored in the ROM 61 will be described with reference to FIGS. Note that “vibration of the drive wheels (front wheels FR, FL)” in the present embodiment indicates a periodic drive slip of the front wheels FR, FL during travel of the vehicle.

  Since the vehicle of this embodiment is a front wheel drive vehicle as described above, there are four vibration patterns P1, P2, P3, and P4 having different vibration modes (vibration types and vibration cycles) as shown in FIG. . The vibration pattern P1 is a pattern in which only the right front wheel FR of the drive wheels (front wheels FR, FL) vibrates, and the vibration cycle thereof is “T1 (for example, 200 ms)”. That is, as shown in FIGS. 4 (a) and 4 (b), in the case of the vibration pattern P1, only the right front wheel FR repeats the driving slip SLP in which the slip amount increases / decreases at a constant period (= T1), while the left front wheel The FL does not drive slip SLP (or even if there is a drive slip SLP, the drive slip SLP has almost no periodic change).

  Further, the vibration pattern P2 is a pattern in which only the left front wheel FL of the drive wheels (front wheels FR, FL) vibrates, and the vibration cycle thereof is “T2 (for example, 200 ms)”. That is, as shown in FIGS. 5A and 5B, in the case of the vibration pattern P2, the right front wheel FR does not perform the driving slip SLP (or even if there is the driving slip SLP, the driving slip SLP is On the other hand, only the left front wheel FL repeats the driving slip SLP in which the slip amount increases or decreases every constant cycle (= T2).

  The vibration pattern P3 is a pattern in which both the left and right drive wheels (front wheels FR, FL) vibrate at the same timing, and the vibration cycle is “T3 (for example, 100 ms)”. That is, as shown in FIGS. 6A and 6B, in the case of the vibration pattern P3, each front wheel FR, FL repeats the driving slip SLP in which the slip amount increases or decreases at every constant period (= T3).

  The vibration pattern P4 is a pattern in which the left and right drive wheels (front wheels FR, FL) vibrate at the same vibration cycle “T4 (for example, 120 ms)”, but the front wheels FR, FL vibrate at different timings. . That is, as shown in FIGS. 7A and 7B, in the case of the vibration pattern P4, when the slip amount of the drive slip SLP of the right front wheel FR increases, the slip amount of the drive slip SLP of the left front wheel FL decreases. On the other hand, when the slip amount of the drive slip SLP of the right front wheel FR decreases, the slip amount of the drive slip SLP of the left front wheel FL increases.

  Next, among the control processing routines executed by the CPU 60 of the present embodiment, a driving wheel vibration detection processing routine executed when the accelerator pedal 17 is depressed when the vehicle is traveling will be described based on the flowchart shown in FIG. .

  In the drive wheel vibration detection processing routine, the CPU 60 detects the wheel speed VW of each front wheel FR, FL based on the signals received from the wheel speed sensors SE5, SE6 for the front wheels FR, FL (step S10). In this respect, in the present embodiment, the wheel speed sensors SE5, SE6 and the CPU 60 function as wheel speed detecting means for detecting the wheel speed VW of the driving wheels (front wheels FR, FL). Subsequently, the CPU 60 identifies vibration patterns P1 to P4 based on the wheel speeds VW of the front wheels FR and FL detected in step S10 (step S11). Specifically, the CPU 60 detects a change in the wheel speed VW of the right front wheel FR, and determines that the right front wheel FR is vibrating when the change is periodic. Similarly, the CPU 60 detects a change in the wheel speed VW of the left front wheel FL, and determines that the left front wheel FL is oscillating when the change is periodic.

  Then, the CPU 60 reads out the vibration patterns P1 to P4 corresponding to the vibration modes of the front wheels FR and FL from the ROM 61. Therefore, in this embodiment, in this embodiment, the wheel speed sensors SE5, SE6 and the CPU 60 detect vibrations generated by the periodic generation of the drive slip SLP when the vehicle travels on the drive wheels (front wheels FR, FL). Also functions as vibration detection means. Further, the CPU 60 also functions as vibration pattern specifying means for specifying the vibration patterns P1 to P4.

  Subsequently, the CPU 60 determines whether or not the vibration pattern specified in step S11 is the vibration pattern P1 (step S12). If the determination result is affirmative, the CPU 60 sets a delay time for delaying the drive timing of the pumps 38 and 39 and the motor M to “Ta (for example, 130 ms)” (see FIG. 3) (step 3). In step S13, the process proceeds to step S21 to be described later. On the other hand, when the determination result of step S12 is negative, the CPU 60 determines whether or not the vibration pattern specified in step S11 is the vibration pattern P2 (step S14). If the determination result is affirmative, the CPU 60 sets the delay time to “Tb (eg, 130 ms)” (see FIG. 3) (step S15), and proceeds to step S21 described later.

  On the other hand, when the determination result of step S14 is negative, the CPU 60 determines whether or not the vibration pattern identified in step S11 is the vibration pattern P3 (step S16). If the determination result is affirmative, the CPU 60 sets the delay time to “Tc (for example, 30 ms)” (see FIG. 3) (step S17), and proceeds to step S21 described later. On the other hand, if the determination result of step S16 is negative, the CPU 60 determines whether or not the vibration pattern identified in step S11 is the vibration pattern P4 (step S18). If the determination result is affirmative, the CPU 60 sets the delay time to “Td (for example, 50 ms)” (see FIG. 3) (step S19), and proceeds to step S21 to be described later. In this regard, in this embodiment, the CPU 60 sets a delay time Ta to Td for delaying the drive timing of the hydraulic pressure variable means (pumps 38 and 39 and the motor M) according to the vibration patterns P1 to P4. It also functions as a time setting means.

  Here, when the CPU 60 executes the processes of steps S10 to S19 described above, it takes about “20 (ms)” for the arithmetic processing time. When the CPU 60 actually increases (increases) the brake hydraulic pressure in the hydraulic pressure circuits 33 and 34 by transmitting a signal to each of the electromagnetic valves 42 to 49, 53 and 57 and the proportional electromagnetic valves 50 and 54. However, it takes about “50 (ms)” to increase the brake fluid pressure. That is, it takes about “70 (ms)” from when the CPU 60 specifies the vibration patterns P1 to P4 until the brake fluid pressure in the fluid pressure circuits 33 and 34 actually increases. Therefore, in the present embodiment, the CPU 60 sets delay times Ta to Td corresponding to the specified vibration patterns P1 to P4, and after the time corresponding to the delay times Ta to Td has elapsed, the hydraulic circuits 33 and 34 The brake fluid pressure inside is increased or decreased. The delay times Ta to Td are set so as to correspond to the vibration patterns P1 to P4, respectively, and are set in advance by experiments, simulations, and the like.

  On the other hand, if the determination result of step S18 is negative, the CPU 60 determines that the drive slip SLP of the front wheels FR, FL is not periodic (that is, the front wheels FR, FL are not vibrating), and The delay time is set to “0 (zero) ms” (step S20), and the process proceeds to step S21. In step S21, the CPU 60 starts measuring the elapsed time T after the vibration patterns P1 to P4 are specified. Subsequently, the CPU 60 determines whether or not the elapsed time T is equal to or longer than the delay time set in any one of steps S13, S15, S17, S19, and S20 (step S22).

  If the determination result in step S22 is a negative determination (elapsed time T <delay time), the CPU 60 repeatedly executes this process until the determination result in step S22 is affirmative. On the other hand, if the determination result in step S22 is affirmative (elapsed time T ≧ delay time), the CPU 60 proceeds to step S23 described later. In this regard, in this embodiment, the CPU 60 also functions as a determination unit that determines whether or not the elapsed time T after the vibration patterns P1 to P4 are specified is equal to or longer than the delay times Ta to Td.

  In step S23, the CPU 60 executes a brake fluid pressure increase / decrease process in the fluid pressure circuits 33 and 34. That is, when increasing the braking force from the wheel cylinder 36a to the right front wheel FR, the CPU 60 first sets the proportional solenoid valve 50 in the energized state to close the proportional solenoid valve 50, while setting the solenoid valve 53 to the closed state. Keep closed. Subsequently, the CPU 60 closes the electromagnetic valve 42 by energizing the electromagnetic valve 42 in order to suppress an increase in braking force by the wheel cylinder 36d for the left rear wheel RL. And CPU60 makes electromagnetic valve 43 open and makes electromagnetic valve 45 closed by making solenoid valves 43 and 45 into a deenergized state.

  When the CPU 60 drives the pump 38 (motor M) in this state, the brake oil in the reservoir 40 is supplied into the wheel cylinder 36a via the right front wheel path 33a. As a result, the brake fluid pressure in the wheel cylinder 36a is increased as the brake fluid pressure in the fluid pressure circuit 33 (the right front wheel path 33a) increases. Accordingly, the braking force applied to the right front wheel FR by the wheel cylinder 36a increases.

  On the other hand, when reducing the braking force from the wheel cylinder 36a to the right front wheel FR, the CPU 60 closes the electromagnetic valve 43 and opens the electromagnetic valve 45 by energizing the electromagnetic valves 43 and 45. And Then, the brake oil in the wheel cylinder 36a is stored in the reservoir 40 via the electromagnetic valve 45, and as a result, the brake hydraulic pressure in the hydraulic circuit 33 (right front wheel path 33a) is reduced.

  Similarly, when increasing the braking force from the wheel cylinder 36b to the left front wheel FL, the CPU 60 first closes the proportional solenoid valve 54 by energizing the proportional solenoid valve 54, while the solenoid valve 57 Is kept closed. Subsequently, the CPU 60 closes the electromagnetic valve 47 by energizing the electromagnetic valve 47 in order to suppress an increase in braking force by the wheel cylinder 36c on the right rear wheel RR. Then, the CPU 60 brings the solenoid valves 46 and 48 into a non-energized state, thereby opening the solenoid valve 46 and closing the solenoid valve 48.

  When the CPU 60 drives the pump 39 (motor M) in this state, the brake oil in the reservoir 41 is supplied into the wheel cylinder 36b via the left front wheel path 34a. As a result, the brake fluid pressure in the wheel cylinder 36b is increased as the brake fluid pressure in the fluid pressure circuit 34 (left front wheel path 34a) increases. Accordingly, the braking force applied to the left front wheel FL by the wheel cylinder 36b increases.

  On the other hand, when reducing the braking force from the wheel cylinder 36b to the left front wheel FL, the CPU 60 closes the electromagnetic valve 46 and opens the electromagnetic valve 48 by energizing the electromagnetic valves 46 and 48. And Then, the brake oil in the wheel cylinder 36b is stored in the reservoir 41 via the electromagnetic valve 48, and as a result, the brake hydraulic pressure in the hydraulic circuit 34 (left front wheel path 34a) is reduced.

After performing the processing as described above, the CPU 60 ends the driving wheel vibration detection processing routine.
Next, a vehicle traction control method according to this embodiment will be described with reference to FIG. As a premise, it is assumed that the vibration pattern specified based on the vibration mode of the front wheels FR and FL is the vibration pattern P1.

  Now, when the vehicle travels based on the depression operation of the accelerator pedal 17 by the passenger, if the front wheels FR and FL as drive wheels vibrate, the vibration patterns P1 to P4 are specified based on the vibration mode of the front wheels FR and FL. . That is, in this case, only the right front wheel FR of the front wheels FR and FL vibrates, so that the vibration pattern P1 is specified and the delay time is set to “Ta (130 ms)”.

  As described above, in the conventional traction control method in which the delay time corresponding to the vibration pattern P1 is not set, the brake hydraulic pressure in the hydraulic pressure circuit 33 (the right front wheel path 33a) is slipped as shown by the broken line in FIG. The driving slip SLP whose amount increases or decreases is delayed by about “70 (ms)”. However, in the present embodiment, the brake hydraulic pressure in the hydraulic circuit 33 (the right front wheel path 33a) is increased after the delay time “Ta” has elapsed since the vibration of the front wheel FR was detected. That is, in consideration of a delay in the change in the brake fluid pressure that always occurs in the traction control device 11 of the vehicle, the timing for starting the brake fluid pressure control in the fluid pressure circuit 33 is delayed.

  Therefore, as indicated by a solid line in FIG. 9, the brake fluid pressure in the fluid pressure circuit 33 changes corresponding to the change in the drive slip SLP of the right front wheel FR. Therefore, the vibration generated based on the periodic driving slip SLP of the right front wheel FR is suppressed by satisfactorily suppressing the driving slip SLP of the right front wheel FR.

Therefore, in this embodiment, the following effects can be obtained.
(1) When the drive wheels (front wheels FR, FL) vibrate due to the periodic drive slip SLP when the vehicle is traveling, vibration patterns P1 to P4 based on the vibration mode are specified, and the specified vibration patterns P1 to P4 are identified. Delay times Ta to Td for delaying the drive timings of the pumps 38 and 39 and the motor M are set according to P4. Here, when the brake fluid pressure in the fluid pressure circuits 33 and 34 is increased, it takes time for the CPU (vibration pattern specifying means) 60 to specify the vibration patterns P1 to P4, or the brake fluid pressure is increased. It takes time to actually start increasing pressure. Therefore, by setting the delay times Ta to Td taking into account the above times, the brakes in the hydraulic pressure circuits 33 and 34 are not delayed from the change timing of the drive slip SLP of the drive wheels (front wheels FR and RL). The hydraulic pressure can be changed. Therefore, when the vehicle is traveling, vibrations of the drive wheels (front wheels FR, RL) that are generated when the brake fluid pressure is changed to suppress the drive slip SLP of the drive wheels (front wheels FR, RL) are preferably suppressed. can do.

  (2) The wheel speed sensors (wheel speed detecting means) SE5, SE6 detect the periodic change in the wheel speed VW of the driving wheels (front wheels FR, RL), so that the vibration of the driving wheels (front wheels FR, RL) is detected. Detected. Therefore, it is possible to suppress an increase in the number of parts by separately providing means for detecting the vibration of the drive wheels (front wheels FR, RL).

  (3) The vibration patterns P1 to P4 corresponding to the vibration modes of the drive wheels (front wheels FR and RL) detected by the CPU (vibration detection means) 60 are read from the ROM (vibration pattern storage means) 61, thereby the vibration patterns P1 to P1. P4 is specified. That is, it is not necessary to perform arithmetic processing using the relational expression in order to specify the vibration patterns P1 to P4. Therefore, the processing load on the CPU (vibration pattern specifying means) 60 can be reduced well.

The embodiment may be changed to another embodiment (another example) as follows.
In the embodiment, the vibration patterns P1 to P4 may not be stored in the ROM 61 in advance. In this case, the CPU 60 detects the vibration mode based on the signals from the wheel speed sensors SE5 and SE6, specifies the drive wheel (front wheels FR, FL) that vibrates from the vibration mode, and sets the vibration cycle of the drive wheel to vibrate to the CPU 60. The vibration pattern is specified by calculating. When configured in this manner, it is not necessary to previously store the vibration patterns P1 to P4 in the storage means such as the ROM 61. That is, an increase in storage capacity due to storing the vibration patterns P1 to P4 in the ROM 61 can be suppressed.

  In the embodiment, the vehicle traction control device 11 may be provided with a vehicle body speed sensor in order to detect vibrations of the driving wheels (front wheels FR, FL). That is, the difference (drive slip) between the vehicle body speed detected by the vehicle speed sensor and the wheel speed VW of the drive wheels (front wheels FR, FL) detected by the wheel speed sensors SE5, SE6 is obtained. The vibration of the drive wheel may be detected based on the change in the above.

  In the embodiment, the present invention may be embodied in a vehicle traction control device mounted on a rear wheel drive vehicle, instead of the vehicle traction control device 11 mounted on the front wheel drive vehicle. In this case, the vibration pattern includes a pattern in which only the right rear wheel RR vibrates, a pattern in which only the left rear wheel RL vibrates, a pattern in which the left and right rear wheels RR and RL vibrate at the same timing, and a left and right rear wheel. There is a pattern in which RR and RL vibrate at different timings.

  -Moreover, you may actualize in the traction control apparatus of the vehicle mounted in a four-wheel drive vehicle. In this case, as a vibration pattern, a pattern in which only one of the wheels (drive wheels) FL, FR, RL, RR vibrates, and a pattern in which both front wheels FR, FL vibrate at the same timing or at different timings. And a pattern in which both rear wheels RR and RL vibrate at the same timing or at different timings. Further, a pattern in which the right front wheel FR and the left rear wheel RL vibrate, a pattern in which the left front wheel FL and the right rear wheel RR vibrate, a pattern in which the right front wheel FR and the right rear wheel RR vibrate, and the left front wheel FL There are a pattern in which the left rear wheel RL vibrates and a pattern in which all the wheels FL, FR, RL, RR vibrate.

  In the embodiment, the first hydraulic circuit 33 is connected to the wheel cylinder 36a for the right front wheel FR and the wheel cylinder 36b for the left front wheel FL, and the second hydraulic circuit 34 is for the right rear wheel RR. The wheel cylinder 36c and the wheel cylinder 36d for the left rear wheel RL may be connected to each other.

The block diagram of the traction control apparatus of the vehicle in this embodiment. The block diagram of the braking force provision mechanism in this embodiment. The table | surface which shows the content of each vibration pattern recorded on ROM. (A) is a graph which shows the change of the drive slip of the right front wheel in the case of the vibration pattern P1, (b) is a graph which shows the change of the drive slip of the left front wheel. (A) is a graph which shows the change of the driving slip of the right front wheel in the case of the vibration pattern P2, (b) is a graph which shows the change of the driving slip of the left front wheel. (A) is a graph which shows the change of the driving slip of the right front wheel in the case of the vibration pattern P3, (b) is a graph which shows the change of the driving slip of the left front wheel. (A) is a graph which shows the change of the driving slip of the right front wheel in the case of the vibration pattern P4, (b) is a graph which shows the change of the driving slip of the left front wheel. The flowchart which shows a driving wheel vibration detection process routine. The graph which shows the correspondence of the change of a drive slip in case only a right front wheel vibrates, and the change of the brake hydraulic pressure in a hydraulic circuit. The graph which shows the correspondence of the change of the drive slip of the conventional drive wheel, and the change of the brake hydraulic pressure in a hydraulic circuit.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Vehicle traction control apparatus, 33 ... 1st hydraulic circuit, 34 ... 2nd hydraulic circuit, 36a, 36b ... Wheel cylinder (braking means), 38, 39 ... Pump (hydraulic pressure variable means), 60 ... CPU (Wheel speed detection means, vibration detection means, vibration pattern identification means, delay time setting means, determination means, control means), 61 ... ROM (vibration pattern storage means), FL ... left front wheel (drive wheel), FR ... right front wheel (Drive wheel), M ... motor (hydraulic pressure varying means), P1 to P4 ... vibration pattern, SE5, SE6 ... wheel speed sensor (wheel speed detection means, vibration detection means), SLP ... drive slip, T ... elapsed time, Ta, Tb, Tc, Td: delay time, VW: wheel speed.

Claims (5)

Vehicle that suppresses drive slip by changing brake fluid pressure when detecting drive slip of drive wheel during traveling of vehicle and suppresses drive slip periodically generated in process of suppressing drive slip of drive wheel Traction control device,
Hydraulic pressure varying means (38, 39, M) for varying the brake hydraulic pressure in the hydraulic circuit (33, 34);
When the brake fluid pressure in the fluid pressure circuit (33, 34) is increased based on the drive of the fluid pressure varying means (38, 39, M), braking force is applied to the drive wheels (FR, FL) of the vehicle. Braking means (36a, 36b) to be applied;
Wheel speed detection means (SE5, SE6, 60) for detecting the wheel speed (VW) of the drive wheels (FR, FL);
Vibration detection means (SE5, SE6, 60) for detecting vibrations generated based on periodic drive slips (SLP) of the drive wheels (FR, FL) during travel of the vehicle;
A predetermined vibration pattern (P1, P2, P3, P4) based on the vibration mode of the drive wheels (FR, FL) detected by the vibration detection means (SE5, SE6, 60) and a plurality of drive wheels. Vibration pattern specifying means (60) for specifying the driving wheel vibrating from
A delay time (Ta for delaying the drive timing of the hydraulic pressure variable means (38, 39, M) according to the vibration pattern (P1, P2, P3, P4) specified by the vibration pattern specifying means (60). , Tb, Tc, Td), delay time setting means (60),
The delay time (Ta) set by the delay time setting means (60) is an elapsed time (T) after the vibration pattern specifying means (60) specifies the vibration pattern (P1, P2, P3, P4). , Tb, Tc, Td) and the determination means (60) for determining whether or not
When the determination unit (60) according to the determination result is affirmative, the braking force said by the braking means (36a, 36b) for the specified vibration to which the driving wheels (FR, FL) is the specific A traction control device for a vehicle, comprising: control means (60) for driving the hydraulic pressure variable means (38, 39, M) so as to be periodically applied based on the vibration pattern . The vibration detection means (SE5, SE6, 60) detects a periodic change in the wheel speed (VW) of the drive wheels (FR, FL) detected by the wheel speed detection means (SE5, SE6, 60). The traction control device for a vehicle according to claim 1, wherein vibrations of the drive wheels (FR, FL) are detected. A vibration pattern storage means (61) for storing a plurality of vibration patterns (P1, P2, P3, P4) having different vibration modes is further provided, and the vibration pattern specifying means (60) includes the vibration detection means (SE5, SE6, SE6). The vibration pattern (P1, P2, P3, P4) corresponding to the vibration mode of the drive wheels (FR, FL) detected by (60) is read from the vibration pattern storage means (61). The vehicle traction control device described. The vibration pattern specifying means (60) includes a plurality of drive wheels (FR, FL) based on the vibration mode of the drive wheels (FR, FL) detected by the vibration detection means (SE5, SE6, 60). The vibration wheel (FR, FL) is identified by calculating the vibration period (T1, T2, T3, T4) of vibration in the identified drive wheel (FR, FL). The vehicle traction control device according to claim 1 or 2, wherein P2, P3, and P4) are specified. Traction of the drive wheel definitive during running of the vehicle (FR, FL) By boosted brake hydraulic pressure of the hydraulic circuit (33, 34) in the case of detecting a (SLP), the driving wheels (FR, FL) In the traction control method for a vehicle, which suppresses the drive slip (SLP) and the drive slip periodically generated in the process of suppressing the drive slip of the drive wheel ,
While driving the vehicle, vibration generated based on the periodic drive slip (SLP) of the drive wheels (FR, FL) is detected, and the drive is performed based on the detected vibration mode of the drive wheels (FR, FL). A vibration pattern (P1, P2, P3, P4) of a predetermined vibration in the wheels (FR, FL) and a driving wheel vibrating from among a plurality of driving wheels are identified, and the identified vibration pattern (P1) , P2, P3, P4) after setting a delay time (Ta, Tb, Tc, Td) for delaying the timing of increasing the brake fluid pressure in the hydraulic circuit (33, 34), When the elapsed time (T) after the vibration pattern (P1, P2, P3, P4) is set becomes equal to or longer than the delay time (Ta, Tb, Tc, Td), the specified vibration is generated. drive wheels are FR, traction control of a vehicle so as to boosted brake hydraulic pressure of the hydraulic circuit (33, 34) in order periodically granted based on the vibration pattern of the braking force is the specific for the FL) Method.

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