JP6460709B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control device.

  Conventionally, as a vehicle control device, EDC (Engine Drag-torque Control) that cancels the slip state of the wheel by controlling the engine brake torque (engine torque) when the wheel tends to slip due to the engine brake is used. An executable one is known (see Patent Document 1). Specifically, in this control, based on the estimated vehicle body speed estimated from the wheel speed of the non-driven wheel and the wheel speed, it is determined whether or not the wheel has a slip tendency, and it is determined that the wheel has a slip tendency. Furthermore, the slip state of the wheel is eliminated by increasing the engine torque.

JP 62-295762 A

  However, in the prior art, when all four wheels are drive wheels as in a four-wheel drive vehicle, it is difficult to accurately estimate the estimated vehicle body speed. For example, when a four-wheel drive vehicle suddenly starts on a low μ road and a wheel spin occurs on all wheels, the estimated vehicle body speed is higher than the actual vehicle speed. In this case, the wheel spin is further increased. When the accelerator is released and the engine brake is activated immediately after the occurrence of the engine, the difference between the high estimated vehicle body speed and the wheel speed that is lowered by the engine brake increases at an early stage. There is a problem that it may be performed at an earlier stage than the case of the vehicle speed.

  Therefore, the present invention is for a vehicle capable of intervening control of engine brake torque (drive source brake torque) thereafter at an appropriate timing even when all the wheels of a four-wheel drive vehicle are wheel-spinned. An object is to provide a control device.

In order to solve the above problems, a vehicle control device according to the present invention includes a wheel speed acquisition unit that acquires a wheel speed, a vehicle body speed estimation unit that estimates an estimated vehicle body speed based on the wheel speed, and the estimated vehicle body speed. Driving to cancel the slip state by determining whether or not the wheel tends to slip based on the wheel speed and controlling the driving source brake torque applied to the wheel when the wheel tends to slip a source braking torque control unit, a vehicle control apparatus for a four-wheel drive vehicle equipped with an acceleration acquiring means for acquiring the acceleration from the acceleration sensor for detecting a longitudinal acceleration of vehicles, the vehicle body speed estimating means, based on the acceleration acquired by the acceleration acquisition means includes limiting means for applying a limit to the increase side of the change amount of the estimated vehicle speed, and increase of the estimated vehicle speed Gets a value obtained by multiplying the limit on the amount of change in the side as the estimated vehicle speed, the drive source braking torque control means, the estimated vehicle speed obtained by multiplying the limit on the increase side of the change amount of the estimated vehicle speed by the restriction means And controlling the driving source brake torque.

  According to this configuration, since the amount of change on the increase side of the estimated vehicle speed is limited based on the acceleration detected by the acceleration sensor, for example, even when all the wheels of a four-wheel drive vehicle have been wheel-spinned, It is possible to prevent the estimated vehicle body speed from being estimated to be a value that is higher than the actual vehicle body speed, and it is possible to intervene in subsequent control of the drive source brake torque at an appropriate timing.

  Further, in the above-described configuration, when the wheel spin prediction means for predicting whether or not the foil spin is generated during the acceleration of the vehicle, the limiting means predicts that the foil spin is generated by the foil spin prediction means. In this case, the change amount on the increase side of the estimated vehicle body speed may be limited based on the acceleration acquired by the acceleration acquisition unit.

  According to this, when it is predicted that foil spin will occur, the amount of change on the increase side of the estimated vehicle body speed is limited based on the acceleration acquired by the acceleration acquisition means. It is possible to prevent the estimated vehicle body speed from being estimated to be higher than the actual vehicle body speed when it occurs.

In the configuration described above, the wheel spin predicting means, a wheel acceleration calculated from the wheel speed obtained by the wheel speed obtaining means, based on the obtained the acceleration in the acceleration obtaining means, the wheel spin It may be configured to predict occurrence.

  According to this, generation | occurrence | production of wheel spin can be suitably estimated based on the wheel acceleration calculated from the wheel speed, and the acceleration detected by the acceleration sensor.

  Further, in the above-described configuration, when the foil spin prediction unit does not predict that the foil spin is generated, the limiting unit uses a preset fixed value to change the estimated vehicle body speed on the increasing side. It may be configured to limit.

  According to this, when it is not predicted that a foil spin will occur, the acceleration is detected without using the acceleration detected by the acceleration sensor (the detected value of the acceleration sensor that is affected by the disturbance such as a step). The estimated vehicle speed can be obtained.

  Further, in the above-described configuration, when the vehicle includes a rough road determination unit that determines whether or not the vehicle is traveling on a rough road, the limiting unit is determined to be traveling on a rough road by the rough road determination unit. In this case, the amount of change on the increase side of the estimated vehicle body speed may be limited using a preset fixed value.

  According to this, since a fixed value that does not depend on the wheel speed is used during rough road traveling, the estimated vehicle body speed can be appropriately limited even if the wheel speed changes greatly due to the influence of disturbance during rough road traveling. .

  Further, in the above-described configuration, in the case where the traction control unit includes a traction control unit that calculates a reduction amount for reducing the driving torque during acceleration of the vehicle and executes traction control based on the reduction amount, the traction control unit includes The drive torque reduction amount may be calculated using an estimated vehicle speed different from the estimated vehicle speed used by the drive source brake torque control means.

  According to this, in the traction control, an estimated vehicle speed that is different from the estimated vehicle speed that is limited based on the acceleration acquired by the acceleration acquisition means is used. Therefore, the traction control and the brake torque control are suitable for each control. The estimated vehicle speed can be calculated. For example, in traction control, the estimated vehicle speed that does not depend on the acceleration sensor can be used by not restricting the brake torque control.

  According to the present invention, even when all the wheels of a four-wheel drive vehicle are wheel-spinned, it is possible to intervene the control of the subsequent drive source brake torque at an appropriate timing.

It is a lineblock diagram of vehicles provided with a control device for vehicles concerning an embodiment of the present invention. It is a block diagram which shows the structure of a hydraulic unit. It is a block diagram which shows the structure of a control part. It is a map for setting a deceleration limit value and an acceleration limit value. It is a flowchart which shows operation | movement of a wheel spin estimation means. It is a flowchart which shows operation | movement of an engine brake torque control means. It is a flowchart which shows operation | movement of a traction control means. It is a time chart which shows the change of each parameter at the time of the wheel being released by the sudden start of the vehicle and then releasing the accelerator and operating the engine brake.

Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
As shown in FIG. 1, the vehicle 2 is a four-wheel drive vehicle in which all of the four wheels 3 are drive wheels, and mainly includes an ECU (Electronic Control Unit) 200 and an example of a vehicle control device. Vehicle brake hydraulic pressure control device 1 and an engine 9 (internal combustion engine) as an example of a drive source.

  The ECU 200 is a control device that controls the entire vehicle including the control of the engine 9, and is connected to the control unit 100 of the vehicle brake hydraulic pressure control device 1 through a communication line. It is possible to send and receive signals. The ECU 200 is connected to a torque sensor 96 that detects the engine torque of the engine 9, an engine speed sensor 97 that detects the speed of the engine 9, and an accelerator pedal stroke sensor 94 that detects the stroke of the accelerator pedal 8. Has been.

  The ECU 200 includes, for example, a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), and an input / output circuit, and inputs from the control unit 100, the sensors 94, 96, 97, and the like. Control is executed by performing each arithmetic processing based on programs and data stored in the ROM.

  The vehicle brake hydraulic pressure control device 1 is a device that appropriately controls the braking force applied to each wheel 3 of the vehicle 2. The vehicular brake hydraulic pressure control device 1 mainly includes a hydraulic unit 10 provided with an oil passage and various components, and a control unit 100 for appropriately controlling various components in the hydraulic unit 10.

Each wheel 3 is provided with a wheel brake FL, RR, RL, FR, and each wheel brake FL, RR, RL, FR is braked by a hydraulic pressure supplied from a master cylinder 5 as a hydraulic pressure source. A wheel cylinder 4 is provided. The master cylinder 5 and the wheel cylinder 4 are each connected to a hydraulic unit 10. Then, the brake hydraulic pressure generated in the master cylinder 5 in accordance with the depression force of the brake pedal 6 (the driver's braking operation) is supplied to the wheel cylinder 4 after being controlled by the control unit 100 and the hydraulic pressure unit 10.
The master cylinder 5 is provided with a booster 7 that assists the operation of the brake pedal 6 by using the suction negative pressure of the engine 9 or the like.

  The control unit 100 includes a wheel speed sensor 91 that detects the wheel speed of each wheel 3, a pressure sensor 92 that detects the pressure of the master cylinder 5, an acceleration sensor 93 that detects acceleration applied to the vehicle 2 in the front-rear direction, A brake pedal stroke sensor 95 that detects the stroke of the brake pedal 6 is connected. The control unit 100 includes, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and an input / output circuit, and inputs from the sensors 91 to 93, 95, and the like. And control is performed by performing various arithmetic processing based on the program and data memorize | stored in ROM. Details of the control unit 100 will be described later.

  As shown in FIG. 2, the hydraulic pressure unit 10 includes a master cylinder 5 that is a hydraulic pressure source that generates a brake hydraulic pressure corresponding to a pedaling force applied to the brake pedal 6 by the driver, and wheel brakes FR, FL, RR, RL. It is arranged between.

  The hydraulic unit 10 is configured by arranging an oil passage and various electromagnetic valves in a pump body 11 which is a base body having an oil passage (hydraulic passage) through which brake fluid flows. The output ports 5a, 5b of the master cylinder 5 are connected to the input port 11a of the pump body 11, and the output port 11b of the pump body 11 is connected to each wheel brake FL, RR, RL, FR. In the normal state, the oil passage is communicated from the input port 11a to the output port 11b in the pump body 11, so that the depression force of the brake pedal 6 is transmitted to each wheel brake FL, RR, RL, FR. It is like that. The hydraulic system connected to the output port 5a of the master cylinder 5 is connected to the wheel brakes FL and RR, and the hydraulic system connected to the output port 5b of the master cylinder 5 is connected to the wheel brakes RL and FR. Each of these systems has substantially the same configuration.

  Each hydraulic system is a normally-open proportional solenoid valve capable of adjusting a difference in hydraulic pressure between upstream and downstream on a hydraulic path connecting the input port 11a and the output port 11b in accordance with a supplied current. Is provided. The pressure regulating valve 12 is provided with a check valve 12a that allows the flow only to the output port 11b side in parallel.

  The hydraulic pressure paths on the side of the wheel brakes RL, FR, RL, FR from the pressure regulating valve 12 are branched in the middle, and each is connected to the output port 11b. An inlet valve 13 that is a normally open proportional solenoid valve is disposed on each hydraulic pressure path corresponding to each output port 11b. Each inlet valve 13 is provided in parallel with a check valve 13a that allows a flow only to the pressure regulating valve 12 side.

  From the hydraulic pressure path between each output port 11b and the corresponding inlet valve 13, a reflux liquid connected between the pressure regulating valve 12 and the inlet valve 13 via an outlet valve 14 made of a normally closed electromagnetic valve, respectively. A pressure path 19B is provided.

  A reservoir 16, a check valve 16a, a pump 17, and an orifice 17a that temporarily absorb excess brake fluid are arranged on the reflux fluid pressure passage 19B in order from the outlet valve 14 side. The check valve 16 a is arranged so as to allow only the flow toward the space between the pressure regulating valve 12 and the inlet valve 13. The pump 17 is driven by a motor 21 and is provided so as to generate pressure between the pressure regulating valve 12 and the inlet valve 13. The orifice 17a attenuates the pulsation of the pressure of the brake fluid discharged from the pump 17 and the pulsation generated when the pressure regulating valve 12 operates.

  The inlet hydraulic pressure passage 19A connecting the input port 11a and the pressure regulating valve 12 and the portion between the check valve 16a and the pump 17 in the reflux hydraulic pressure passage 19B are connected by a suction hydraulic pressure passage 19C. A suction valve 15 that is a normally closed electromagnetic valve is disposed in the suction fluid pressure path 19C.

  In addition, the pressure sensor 92 is provided in the introduction hydraulic pressure passage 19A only in the direction corresponding to the output port 5b of the master cylinder 5. The pressure sensor 92 is connected to the control unit 100.

  In the hydraulic pressure unit 10 configured as described above, the solenoid valves are not energized at normal times, and the brake hydraulic pressure introduced from the input port 11a passes through the pressure regulating valve 12 and the inlet valve 13 to the output port 11b. It is output and applied to each wheel cylinder 4 as it is. When the excessive brake fluid pressure in the wheel cylinder 4 is reduced, for example, when antilock brake control is performed, the corresponding inlet valve 13 is closed and the outlet valve 14 is opened to open the brake fluid through the reflux hydraulic pressure passage 19B. To the reservoir 16 and the brake fluid in the wheel cylinder 4 can be drained. Further, when the wheel cylinder 4 is pressurized when the driver does not operate the brake pedal 6, the intake valve 15 is opened and the motor 21 is driven, so that the wheel is positively driven by the pressure applied by the pump 17. Brake fluid can be supplied to the cylinder 4. Furthermore, when it is desired to adjust the degree of pressurization of the wheel cylinder 4, it can be adjusted by adjusting the current flowing through the pressure regulating valve 12.

Next, details of the ECU 200 and the control unit 100 will be described.
As shown in FIG. 3, the ECU 200 controls engine brake torque control (hereinafter also referred to as “EDC”) for controlling engine brake torque applied from the engine 9 to the wheel 3, and during wheel spin of the wheel 3. An engine torque control unit 210 capable of executing drive torque control (Traction Control System: hereinafter also referred to as “TCS”) for controlling drive torque applied from the engine 9 to the wheel 3 is provided.

  Here, the driving torque is a torque transmitted from the engine 9 to the driving wheel via a transmission (reduction gear). If the driving torque during acceleration of the vehicle 2 is positive, it is negative when the vehicle 2 is decelerated by engine braking. Torque. The negative drive torque during deceleration corresponds to the engine brake torque described above.

  Specifically, when executing the EDC, the engine torque control unit 210 adds the amount of increase in the drive torque output from the control unit 100 to the current drive torque, thereby achieving a target drive torque. Torque is calculated, and the engine torque of the engine 9 is controlled so that the drive torque becomes the target torque. Specifically, the engine torque control unit 210 determines the target value of the engine torque from the target torque and the estimated gear ratio so that the driving torque of the driving wheel becomes the target torque, and the engine torque detected by the torque sensor 96 is the same as described above. The engine torque is controlled to achieve the target value. Here, the estimated gear ratio is calculated based on, for example, the engine speed detected by the engine speed sensor 97 and the average wheel speed of the drive wheels calculated based on the signal from the wheel speed sensor 91. Can do.

  Further, when executing the TCS, the engine torque control unit 210 calculates the target torque by subtracting the decrease amount of the drive torque output from the control unit 100 from the current drive torque, Thereafter, as in the case of EDC, the engine torque is controlled so that the drive torque becomes the target torque.

  The engine torque control unit 210 performs normal engine control based on the accelerator operation amount or the like when no increase or decrease in drive torque is received from the control unit 100.

  The control unit 100 mainly estimates the estimated vehicle body speed based on the wheel speed detected by the wheel speed sensor 91 and the acceleration detected by the acceleration sensor 93 (hereinafter referred to as “acceleration sensor value”), and the above-described function. It has a function of setting a target torque and a reduction amount of driving torque for use in EDC or TCS. The control unit 100 is configured to execute EDC or TCS via the ECU 200 by outputting a reduction amount of the target torque or the drive torque to the ECU 200.

  Specifically, the control unit 100 includes a wheel speed acquisition unit 110, an acceleration acquisition unit 120, an ABS determination unit 131, a rough road determination unit 132, a failure determination unit 133, a wheel spin prediction unit 134, and a vehicle body speed estimation. Means 140, engine brake torque control means 150 as an example of drive source brake torque control means, traction control means 160, and storage means 170 are provided.

  The wheel speed acquisition means 110 is a means for acquiring the wheel speed detected by the wheel speed sensor 91. The vehicle speed estimation means 140, the ABS determination means 131, the rough road determination means 132, and the wheel spin prediction means are used as the acquired wheel speed. It outputs to 134.

  The acceleration acquisition unit 120 is a unit that acquires an acceleration sensor value from the acceleration sensor 93, and uses the acquired acceleration sensor value as a vehicle speed estimation unit 140 (more specifically, a limiting unit 141 described later), a failure determination unit 133, and a wheel spin. It outputs to the prediction means 134.

  The ABS determination means 131 is based on the signal output from the brake pedal stroke sensor 95, the wheel speed output from the wheel speed acquisition means 110, and the estimated vehicle body speed output from the vehicle body speed estimation means 140. , Means for determining whether to start anti-lock brake control (hereinafter also referred to as “ABS”). Specifically, the ABS determination unit 131 determines whether or not the brake pedal 6 is depressed based on a signal from the brake pedal stroke sensor 95, and the slip amount calculated based on the wheel speed and the estimated vehicle body speed is determined. By determining whether or not the ABS start threshold value has been reached, it is determined whether or not ABS execution is to be started.

  Then, the ABS determination means 131 determines that the ABS is started when it is determined that the brake pedal 6 is depressed and the slip amount is equal to or greater than the ABS start threshold. Here, the ABS determination means 131 calculates the slip amount for each wheel 3, and satisfies the slip amount condition when the slip amount condition is the above condition in at least one of the plurality of wheels 3. It is determined that

  Then, after determining that the ABS is started, the ABS determination unit 131 outputs an ABS execution signal indicating that the ABS is being executed to the limiting unit 141 until the ABS end condition is satisfied. Here, the ABS termination condition may be, for example, that the depression of the brake pedal 6 is released.

  The rough road determination means 132 is a means for determining whether or not the vehicle 2 is traveling on a rough road based on the wheel speed output from the wheel speed acquisition means 110. Here, the bad road determination can be performed based on, for example, the fluctuation amount of the wheel speed. When the rough road determination unit 132 determines that the vehicle is traveling on a rough road, the rough road determination unit 132 outputs a rough road signal indicating the rough road to the restriction unit 141.

  The failure determination unit 133 is a unit that determines whether or not the acceleration sensor 93 has failed based on the acceleration sensor value output from the acceleration acquisition unit 120. Here, the failure determination can be performed, for example, by comparing the wheel acceleration calculated from the wheel speed and the acceleration sensor value. When the failure determination unit 133 determines that the acceleration sensor 93 has failed, the failure determination unit 133 outputs a failure signal indicating the failure to the restriction unit 141.

  The wheel spin predicting unit 134 receives the wheel speed output from the wheel speed acquiring unit 110, the wheel acceleration calculated from the wheel speed, the acceleration sensor value output from the acceleration acquiring unit 120, and the vehicle body speed estimating unit 140. This is means for predicting whether or not wheel spin is generated during acceleration of the vehicle 2 based on the estimated vehicle body speed that is output. The determination of the foil spin prediction by the foil spin prediction means 134 will be described in detail later. When the foil spin prediction unit 134 predicts that a foil spin will occur, the foil spin prediction unit 134 outputs a foil spin prediction signal indicating that to the limiting unit 141.

  The vehicle body speed estimation means 140 is a means for estimating the estimated vehicle body speed based on the wheel speed output from the wheel speed acquisition means 110, and suppresses the amount of change in the estimated vehicle body speed from the previous value from becoming too large. Limiting means 141 is provided. The limiting unit 141 sets a deceleration limit value for limiting the amount of change on the decrease side of the estimated vehicle speed based on the signals output from the determination units 131 to 134 and the map shown in FIG. At the same time, an acceleration limit value for limiting the amount of change on the increase side of the estimated vehicle body speed is set.

  Specifically, when receiving a failure signal from the failure determination unit 133, the limiting unit 141 sets the deceleration limit value to a preset fixed value −Ld and sets the acceleration limit value to a preset fixed value. Set to the value La. Here, in this embodiment, acceleration / vehicle speed during acceleration is indicated by a positive value, acceleration / vehicle speed during deceleration is indicated by a negative value, and accordingly, the deceleration limit value is expressed by a negative value. The acceleration limit value is indicated by a positive value. The fixed value -Ld can be set to the maximum value of the magnitude of acceleration that can occur during deceleration of the vehicle 2, for example, and the fixed value La can be set to the magnitude of acceleration that can occur during acceleration of the vehicle 2, for example. The maximum value can be set.

  When receiving the ABS execution signal from the ABS determination unit 131, the limiting unit 141 sets the deceleration limit value to the acceleration sensor value and sets the acceleration limit value to the fixed value La. When the rough road signal is received from the rough road determination means 132, the limiting means 141 sets the deceleration limit value to the fixed value −Ld and sets the acceleration limit value to the fixed value La.

  When receiving the wheel spin prediction signal from the wheel spin prediction unit 134, the limiting unit 141 sets the deceleration limit value to the acceleration sensor value and sets the acceleration limit value to the acceleration sensor value.

  The limiting means 141 sets the deceleration limit value to the acceleration sensor value and sets the acceleration limit value to a fixed value set in advance according to the vehicle body speed in normal times, that is, in cases other than the four conditions described above. . Specifically, the limiting unit 141 acquires a fixed value corresponding to the vehicle body speed from a map (not shown) showing the relationship between the vehicle body speed and a plurality of fixed values set to correspond to the vehicle body speed. The value is set as the acceleration limit value.

  The vehicle body speed estimation unit 140 determines whether or not the change amount of the wheel speed obtained by subtracting the previous value from the current value of the wheel speed is within the range of the deceleration limit value set by the limit unit 141 and the acceleration limit value or less. If it is within the range, the provisional vehicle body speed is calculated by adding the calculated change amount to the previous value of the wheel speed. In addition, when the change amount is less than the deceleration limit value, the vehicle body speed estimation unit 140 calculates the temporary vehicle body speed by adding the deceleration limit value to the previous value of the wheel speed, and the change amount is greater than the acceleration limit value. If it is larger, the temporary vehicle body speed is calculated by adding the acceleration limit value to the previous value of the wheel speed.

  Then, the vehicle body speed estimation means 140 calculates the above-mentioned temporary vehicle body speed for each wheel 3, and then sets (estimates) the lowest temporary vehicle body speed among these temporary vehicle body speeds as the estimated vehicle body speed.

  As shown in FIG. 3, when the estimated vehicle body speed is set, the vehicle body speed estimating means 140 outputs the set estimated vehicle body speed to the ABS determining means 131, the wheel spin predicting means 134 and the engine brake torque control means 150.

  The engine brake torque control means 150 is a means for determining whether or not the wheel 3 has a slip tendency and controlling the engine brake torque applied to the wheel 3 when the wheel 3 has a slip tendency to eliminate the slip state. is there. Specifically, the engine brake torque control unit 150 calculates a slip amount based on the estimated vehicle body speed and wheel speed output from the vehicle body speed estimation unit 140, and the calculated slip amount is an EDC start / end threshold TH1. It is determined whether or not the wheel 3 has a slip tendency by determining whether or not the above has occurred.

  Here, the slip amount may be the maximum slip amount among the plurality of slip amounts calculated for each wheel 3, or may be an average value of the plurality of slip amounts. The wheel speed may be directly output from the wheel speed acquisition unit 110 to the engine brake torque control unit 150, or may be output from the wheel speed acquisition unit 110 to the engine brake torque control unit 150 via the vehicle body speed estimation unit 140. May be.

  When it is determined that the wheel 3 is in a slip tendency, the engine brake torque control unit 150 calculates an increase amount of the drive torque based on the slip amount, and outputs the calculated increase amount to the engine torque control unit 210. Thus, the engine brake torque is controlled via the engine torque control unit 210.

  The traction control means 160 is a means for executing TCS when a foil spin occurs. Specifically, the traction control unit 160 includes a second vehicle body speed estimation unit 162.

  The second vehicle body speed estimation means 162 calculates a change amount of the wheel speed, and when the calculated change amount is less than a predetermined acceleration limit value (fixed value La), the calculated change amount is added to the previous value of the wheel speed. Thus, the temporary vehicle body speed is calculated, and when the calculated change amount is equal to or greater than the acceleration limit value, the temporary vehicle body speed is calculated by adding the acceleration limit value (fixed value La) to the previous value of the wheel speed. The second vehicle body speed estimating means 162 calculates the above-mentioned temporary vehicle body speed for each wheel 3, and then sets (estimates) the lowest temporary vehicle body speed among these temporary vehicle body speeds as the estimated vehicle body speed. In addition, what is necessary is just to employ | adopt a well-known method as the estimation method of the variation | change_quantity of wheel speed.

  Then, the traction control means 160 determines whether or not the wheels tend to slip during acceleration of the vehicle based on the estimated vehicle speed for the TCS estimated by the second vehicle speed estimation means 162 and the wheel speed. . If the wheels tend to slip during acceleration of the vehicle, the traction control means 160 calculates a reduction amount for reducing the driving torque based on the estimated vehicle body speed and wheel speed for TCS. By outputting the reduction amount to the engine torque control unit 210, the drive torque is controlled via the engine torque control unit 210.

  The storage means 170 stores the map shown in FIG. 4, each threshold value, the previous value of the wheel speed, and the like.

  Next, the operation of the control unit 100 will be described in detail with reference to FIGS. First, the foil spin prediction determination by the foil spin prediction means 134 will be described with reference to FIG.

  As shown in FIG. 5, the wheel spin prediction means 134 first acquires the wheel speed, the estimated vehicle body speed, and the acceleration sensor value (S1). Here, the estimated vehicle body speed acquired by the wheel spin prediction unit 134 is limited to a normal estimated vehicle body speed (fixed value due to a difference in speed) before the wheel spin prediction unit 134 predicts that wheel spin will still occur. The estimated vehicle body speed is limited by the acceleration sensor value after predicting that wheel spin will occur.

  After step S1, the wheel spin prediction means 134 calculates the wheel acceleration for each wheel 3 from the wheel speed of each wheel 3 (S2). After step S2, the wheel spin prediction means 134 determines whether or not the acceleration sensor value is greater than 0 (S3).

  If it is determined in step S3 that the acceleration sensor value is greater than 0 (Yes), the wheel spin prediction unit 134 adds the predetermined offset value to the acceleration sensor value for each wheel acceleration of the same wheel ( Hereinafter, it is also referred to as “acceleration threshold value”). Here, the “same side wheel” refers to left and right front and rear wheels. Specifically, in step S4, the wheel spin prediction means 134 at least satisfies the conditions that the left and right front wheel accelerations are greater than or equal to the acceleration threshold and the right and left front wheel accelerations are greater than or equal to the acceleration threshold value. If one of the conditions is met, the determination is Yes.

  When it determines with each wheel acceleration of the same side wheel being more than an acceleration threshold value in step S4 (Yes), the wheel spin estimation means 134 counts up a counter (S5). When it is determined in step S4 that each wheel acceleration of the same wheel is less than the acceleration threshold (No), the wheel spin prediction means 134 determines whether or not each wheel speed of the same wheel is equal to or less than the estimated vehicle body speed. Is determined (S6).

  Specifically, in step S6, the wheel spin prediction unit 134 determines that the left and right front wheel speeds are less than or equal to the estimated vehicle body speed and the right and left front wheel speeds are less than or equal to the estimated vehicle body speed. If at least one of the conditions is met, the determination is Yes.

  If it is determined in step S6 that each wheel speed of the same side wheel is equal to or less than the estimated vehicle body speed (Yes), or if it is determined in step S3 that the acceleration sensor value is 0 or less (No), wheel spin prediction is performed. The means 134 clears the counter (S7). After step S5 or step S7, or when it is determined in step S6 that each wheel speed of the same side wheel is larger than the estimated vehicle body speed (No), the wheel spin prediction means 134 has a counter equal to or greater than the determination threshold value TH2. It is determined whether or not (S8).

  If it is determined in step S8 that the counter is greater than or equal to the determination threshold TH2, the wheel spin prediction means 134 predicts that a wheel spin will occur, sets the wheel spin prediction flag F to 1 (S9), and performs this control. finish. If it is determined in step S8 that the counter is less than the determination threshold TH2, the wheel spin prediction unit 134 sets the wheel spin prediction flag to 0 (S10), and ends this control.

Next, the control (EDC) by the engine brake torque control means 150 will be described with reference to FIG.
As shown in FIG. 6, the engine brake torque control means 150 first acquires the wheel speed and the estimated vehicle body speed (S11). Here, the estimated vehicle speed acquired by the engine brake torque control means 150 is an estimated vehicle speed limited by each limit value set in accordance with each condition shown in FIG. 4, but it is predicted that a wheel spin will occur in particular. After that, the estimated vehicle speed is limited by the acceleration sensor value (hereinafter also referred to as an estimated vehicle speed for EDC). In the following description, an example in which the engine brake torque control means 150 acquires the estimated vehicle body speed for EDC related to the present invention will be described as a representative example.

  After step S11, the engine brake torque control means 150 calculates the slip amount by subtracting the wheel speed from the estimated vehicle speed for EDC (S12). After step S12, the engine brake torque control means 150 determines whether or not the slip amount is equal to or greater than the EDC start / end threshold value TH1 (S13).

  If it is determined in step S13 that the slip amount is equal to or greater than the EDC start / end threshold value TH1 (Yes), the engine brake torque control means 150 calculates the increase amount of the drive torque based on the slip amount (S14). Then, the calculated increase amount is transmitted to the engine torque control unit 210 (S15), and this control is finished. If it is determined in step S13 that the slip amount is less than the EDC start / end threshold TH1 (No), the engine brake torque control means 150 ends this control as it is.

  Next, control (TCS) by the traction control means 160 will be described with reference to FIG.

  As shown in FIG. 7, the traction control means 160 first determines whether or not a wheel spin has occurred by determining whether or not the wheel tends to slip during acceleration of the vehicle (S21). If it is determined in step S21 that wheel spin has occurred (Yes), the traction control means 160 determines the amount of decrease in drive torque based on the slip amount that is the difference between the wheel speed and the estimated vehicle speed for TCS. Calculate (S23). After step S23, the traction control means 160 transmits the calculated decrease amount to the engine torque control unit 210 (S24), and this control is finished. If it is determined in step S21 that no foil spin has occurred (No), the traction control means 160 ends this control as it is.

  Next, TCS and EDC in the case where the vehicle brake 2 suddenly starts on the low μ road and the wheel spin is generated in all the wheels 3 and then the accelerator is released and the engine brake is operated will be described. 8C and 8D, “1” indicates that TCS or EDC is being executed, and “0” indicates that TCS or EDC is not being executed.

  As shown in FIG. 8A, when the driver depresses the accelerator pedal 8 strongly from the time t0, the wheel speed Vw of each wheel 3 rises away from the actual vehicle speed Va. The estimated vehicle speed Vc estimated based on each wheel 3 also increases along the wheel speed Vw. Then, as shown in FIGS. 8B and 8C, when the wheel spin prediction means 134 predicts that wheel spin will occur based on the acceleration sensor value and wheel acceleration (time t1), the vehicle body speed estimation means 140 Calculation of the estimated vehicle speed Vce for EDC is started based on the acceleration limit value (acceleration sensor value) for EDC.

  After the time t1, the estimated vehicle speed Vce for EDC is limited by the acceleration limit value (acceleration sensor value) for EDC, and takes a value near the actual vehicle speed Va along the actual vehicle speed Va. It rises.

  On the other hand, the second vehicle body speed estimating means 162 calculates an estimated vehicle body speed Vct for TCS. The estimated vehicle speed Vct for TCS is a value that is higher than the acceleration limit value (fixed value La) for TCS. Therefore, the wheel speed Vw takes a value near the wheel speed Vw for a while after time t1. And then limited by the acceleration limit value for TCS (time t2). As a result, the estimated vehicle speed Vct for TCS is calculated to a value higher than the estimated vehicle speed Vce for EDC.

  If foil spin occurs at time t2, the traction control means 160 starts TCS, and thereafter ends TCS when the TCS end conditions are met (time t21, t3). TCS is started when the start conditions are satisfied (time t22).

  Thereafter, as shown in FIGS. 8A to 8C, when the actual vehicle speed Va is switched from increasing to decreasing, that is, when the acceleration sensor value becomes 0 or less (time t3), the wheel spin predicting means 134 performs the wheel spin. Set the prediction flag F to 0. Then, the vehicle body speed estimation means 140 calculates the estimated vehicle body speed Vc using the deceleration limit value and the acceleration limit value in the normal state with the estimated vehicle body speed Vce for EDC as a reference. Thereby, in the EDC performed after time t3, it is possible to use the estimated vehicle speed Vc that takes a value close to the actual vehicle speed Va.

  As shown in FIGS. 8A and 8D, after the time t3, when the slip amount becomes equal to or greater than the EDC start / end threshold value TH1 (time t4), the engine brake torque control means 150 starts executing EDC. . Thereafter, when the slip amount becomes less than the EDC start / end threshold value TH1 (time t5), the engine brake torque control means 150 ends the EDC. Similarly thereafter, the engine brake torque control means 150 starts (time t6) and ends (time t7) EDC based on the slip amount and the EDC start / end threshold value TH1.

According to the above, the following effects can be obtained in the present embodiment.
During the wheel spin before entering the EDC (during the wheel spin after the foil spin prediction), the amount of change on the increase side of the estimated vehicle speed Vce is limited based on the acceleration sensor value. Even in such a case, it is possible to prevent the estimated vehicle body speed Vce from being estimated to a value that is higher than the actual vehicle body speed Va, and to intervene the subsequent EDC at an appropriate timing. .

  Since the wheel spin is predicted based on the wheel acceleration and the acceleration sensor value, it is possible to appropriately predict the occurrence of the wheel spin.

  At the time of acceleration when the occurrence of wheel spin is not predicted, the acceleration limit value is set to a fixed value (a fixed value corresponding to La or speed) as shown in FIG. Since the restriction is performed without using it, an appropriate estimated vehicle body speed can be obtained.

  When traveling on rough roads, the acceleration limit value is set to a fixed value La that does not depend on the wheel speed. Therefore, even if the wheel speed changes significantly due to the influence of disturbance on rough roads, the estimated vehicle speed is appropriately limited. can do.

  In TCS, the estimated vehicle speed Vct limited by a higher fixed value La is used instead of the estimated vehicle speed Vce limited based on the acceleration sensor value, so that the difference between the estimated vehicle speed Vct and the wheel speed Vw becomes too large. Therefore, it is possible to suppress the decrease amount of the drive torque from becoming too large.

  In addition, this invention is not limited to the said embodiment, It can utilize with various forms so that it may illustrate below. In the following description, the same reference numerals are given to members having substantially the same structure as in the above embodiment, and the description thereof is omitted.

  In the embodiment, the engine 9 is exemplified as the drive source. However, the present invention is not limited to this, and the drive source may be, for example, an electric motor provided in an electric vehicle or a hybrid vehicle.

  In the above embodiment, the vehicle brake hydraulic pressure control device 1 (brake pressure control means) is exemplified as the vehicle control device. However, the present invention is not limited to this, and for example, the vehicle control device may be an ECU (drive source). A control device) and a vehicle brake fluid pressure control device. In this case, for example, the vehicle body speed estimation means, engine brake torque control means, traction control means, etc. may be provided in the ECU.

DESCRIPTION OF SYMBOLS 1 Vehicle brake hydraulic pressure control apparatus 3 Wheel 93 Acceleration sensor 100 Control part 110 Wheel speed acquisition means 120 Acceleration acquisition means 140 Car body speed estimation means 141 Limiting means 150 Engine brake torque control means

Claims (6)

Wheel speed acquisition means for acquiring a wheel speed, body speed estimation means for estimating an estimated vehicle body speed based on the wheel speed, and whether or not the wheel tends to slip based on the estimated vehicle body speed and the wheel speed. determines a drive source braking torque control means for said wheels to eliminate the driving source slipping state by controlling the braking torque applied to the wheel when it is the slip tends to detect the longitudinal acceleration of vehicles An acceleration acquisition means for acquiring the acceleration from an acceleration sensor; and a vehicle control device for a four-wheel drive vehicle,
The vehicle body speed estimation means has a limiting means for restricting a change amount on the increase side of the estimated vehicle body speed based on the acceleration acquired by the acceleration acquisition means, and a change on the increase side of the estimated vehicle body speed Get a limited amount as the estimated body speed,
The drive source brake torque control means controls the drive source brake torque using an estimated vehicle body speed in which the limiting means limits the amount of change on the increase side of the estimated vehicle body speed. apparatus. Foil spin prediction means for predicting whether or not foil spin occurs during vehicle acceleration,
The limiting means limits the amount of change on the increase side of the estimated vehicle body speed based on the acceleration acquired by the acceleration acquiring means when it is predicted that the foil spin is generated by the foil spin predicting means. The vehicle control device according to claim 1. The wheelspin predicting means, characterized the wheel acceleration calculated from the obtained wheel speed by the wheel speed obtaining means, wherein on the basis of the acceleration and acquired by the acceleration acquisition means, to predict the occurrence of wheelspin The vehicle control device according to claim 2.   The restricting means restricts the amount of change on the increase side of the estimated vehicle body speed using a preset fixed value when it is not predicted that the foil spin is generated by the foil spin predicting means. The vehicle control device according to claim 2 or 3. A rough road judging means for judging whether or not the vehicle is traveling on a rough road;
The limiting means limits the amount of change on the increase side of the estimated vehicle body speed using a preset fixed value when the rough road determination means determines that the vehicle is traveling on a rough road. The vehicle control device according to any one of claims 2 to 4. A traction control means for calculating a reduction amount for reducing the driving torque during acceleration of the vehicle and executing traction control based on the reduction amount;
6. The traction control unit calculates the amount of decrease in the drive torque using an estimated vehicle body speed different from the estimated vehicle body speed used in the drive source brake torque control unit. The vehicle control device according to claim 1.

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