JP4306553B2 - Traction control device - Google Patents

Description

  The present invention relates to a traction control device capable of suppressing vibrations generated due to slip.

  Conventionally, as a traction control device for suppressing vibration generated due to slip, those shown in Patent Literature 1 and Patent Literature 2 have been proposed.

  The traction control device disclosed in Patent Document 1 detects vibrations of the drive wheels, and when vibrations are detected, particularly the differential component of the feedback correction torque is reduced and only the component that lowers the target drive torque is restricted. . Thereby, the change which increases a drive torque is restrict | limited, A vibration is gradually settled by a drive torque being gradually reduced.

In the traction control device disclosed in Patent Document 2, vibration during acceleration is detected, and driving torque is held when vibration is detected. Thereby, vibration can be reduced.
Japanese Patent Laid-Open No. 7-324641 JP-A-5-178189

  However, when the change that increases the drive torque is limited as in the traction control device disclosed in Patent Document 1, the convergence is slow even if the vibration is reduced. Further, even if the driving torque is maintained as in the traction control device disclosed in Patent Document 2, the convergence of vibration is similarly slow. In Patent Document 2, the throttle is lowered in order to maintain the driving torque. However, this is performed only to maintain the driving torque, and the vibration cannot be converged.

  In view of the above points, an object of the present invention is to provide a traction control device capable of converging vibrations generated due to slip earlier.

  The above-mentioned vibrations are drive system torsional vibrations that are caused by a sudden change in the driving force that occurs when the wheel slip rate exceeds the μ peak determined from the relationship between the slip rate and the road surface friction coefficient μ. Presumed to be. In other words, this is windup vibration in which the differential vibrates up and down.

  In the traction control, since the driving force control is executed so that the slip ratio is maintained in the vicinity of the μ peak, it is assumed that such a drive system torsional vibration is likely to be sustained.

  Therefore, it was concluded that in order to converge such vibration more quickly, it is necessary to instantaneously reduce the driving force when the vibration occurs.

Accordingly, in the first aspect of the invention, the degree of vibration of the wheel is obtained by the degree-of-vibration detecting means, and the reduction amount determining means determines the reduction amount of the engine torque target value based on the detected degree of vibration. as control means controls the drive torque to the vibration reduction amount determined at this time by the vibration degree detecting means subtracts the engine torque target value or found before being detected, becomes the subtracted engine torque target value Yes.

  Thus, when wheel vibration occurs, the engine torque target value is set to a value that is reduced by a predetermined amount compared to before the wheel vibration occurs. That is, it is determined that the wheel vibration has occurred, and at the same time, the engine torque target value is lowered to a region where the wheel vibration does not occur. For this reason, it becomes possible to converge wheel vibration more quickly.

  For example, as shown in claim 2, the vibration degree detection means includes means for detecting wheel acceleration, and detects the vibration degree of the wheel based on the wheel acceleration obtained by this means.

  In the invention according to claim 3, when it is determined by the reduction degree determination means that the wheel vibration has occurred when it is determined by the vibration degree detection means based on the wheel acceleration. The maximum value of the wheel acceleration is obtained, and the reduction amount of the engine torque target value is obtained from the maximum value of the wheel acceleration.

  In this way, if the reduction amount of the engine torque target value is obtained based on the maximum value of the wheel acceleration when the wheel vibration occurs, it is based on the wheel acceleration whose magnitude varies depending on the magnitude of the wheel vibration. Thus, the reduction amount of the engine torque target value is obtained. For this reason, it is possible to accurately obtain the reduction amount of the engine torque target value necessary for making the region in which no wheel vibration occurs.

  According to a fourth aspect of the present invention, the reduction amount determining means stores a relationship between the wheel acceleration and the reduction amount of the engine torque target value as a map, and the engine corresponding to the maximum value of the wheel acceleration based on the map. It is characterized by obtaining a reduction amount of the torque target value.

  As described above, if the reduction amount of the engine torque target value is obtained based on the map, it is possible to reduce the processing load when executing the traction control as compared with the case of obtaining by calculation.

  Although there is a correlation between the wheel acceleration during wheel vibration and the reduction amount of the engine torque target value, these correlations are not completely proportional. However, the reduction amount of the engine torque target value can be obtained more accurately.

  Further, as shown in claim 5, the vibration degree detecting means has means for detecting the amplitude of the wheel speed, and detects the degree of vibration of the wheel based on the wheel speed amplitude obtained by this means. You can also.

  In this case, when it is determined by the vibration degree detecting means that the wheel vibration has occurred from the amplitude of the wheel speed, the reduction amount determining means determines that the wheel vibration has occurred. When this is done, the maximum value of the wheel speed amplitude can be obtained, and the reduction amount of the engine torque target value can be obtained from the maximum value of the wheel speed amplitude.

  Thereby, the same effect as that of the third aspect can be obtained.

  Also in this case, as shown in claim 7, the reduction amount determination means stores a relationship between the wheel speed amplitude and the reduction amount of the engine torque target value as a map, and based on this map, The reduction amount of the engine torque target value corresponding to the maximum value of the wheel speed amplitude can be obtained.

  Thereby, the same effect as that of claim 4 can be obtained.

  The invention according to claim 8 is characterized in that the reduction amount determination means sets a value obtained by multiplying the engine torque target value by a predetermined coefficient as the maximum value of the reduction amount of the engine torque target value. Yes.

  When the torque reduction is increased, the wheel vibration can be converged faster, but there is a contradiction that the vehicle speed is stalled. Therefore, by limiting the maximum value of the final reduction amount, it is possible to suppress the vehicle speed from stalling and to prevent the driver from feeling stalled.

(First embodiment)
A traction control device to which an embodiment of the present invention is applied is shown in FIG.

  FIG. 1 shows an overall configuration of a vehicle control system that realizes a traction control device according to an embodiment of the present invention. Hereinafter, the configuration of the vehicle control system will be described with reference to this figure.

  As shown in FIG. 1, the vehicle control system includes an engine EG, a transmission GS, a brake fluid pressure control device BPC, and wheel cylinders Wfl, Wfr, Wrl, Wrr provided for each wheel FL, FR, RL, RR. The configuration includes various sensor groups and an electronic control unit (hereinafter referred to as ECU) 1.

  Wheels FL, FR, RL, and RR indicate the left front, right front, left rear, and right rear wheels, respectively. “**” used in the following description corresponds to a subscript indicating the wheels FL to RR.

  The engine EG is an internal combustion engine including a throttle control device TH and a fuel injection device FI, and is driven based on an operation amount at an accelerator pedal AP and an engine control signal from the ECU 1 in response to a driver's drive request. Specifically, the throttle control device TH controls the main throttle opening of the main throttle valve MT according to the operation of the accelerator pedal AP, and drives the sub throttle valve ST according to the control signal from the ECU 1. The throttle opening is controlled. The fuel injection device FI is driven based on a control signal from the ECU 1 to control the fuel injection amount. The engine speed in the engine EG is controlled by driving the throttle control device TH and the fuel injection device FI.

  The vehicle shown in the present embodiment is of the FR drive system, and the engine EG is connected to the wheels RL and RR behind the vehicle via the transmission GS, the center differential DC, and the rear differential DR. Yes. Therefore, the wheels FL and FR are driven wheels, and the wheels RL and RR are drive wheels.

  The transmission GS switches the gear position of the transmission. The gear position in the transmission GS is transmitted to the ECU 1 from a gear position sensor provided in the transmission GS, and is adjusted based on a gear position control signal from the ECU 1. Yes.

  The brake fluid pressure control device BPC is configured so that each wheel FL, FR, RL, RR, respectively, according to the operation amount of the brake pedal BP depressed in response to the driver's braking request and the braking request based on the traction control executed by the ECU 1. The brake fluid pressure (wheel cylinder pressure) applied to the wheel cylinders Wfl, Wfr, Wrl, Wrr attached to the wheel cylinders is adjusted. Specifically, the brake fluid pressure control device BPC is provided with a master cylinder (not shown) and a pressure sensor PS for detecting an output brake fluid pressure (master cylinder pressure) of the master cylinder. Then, an output signal of the pressure sensor PS is configured to be input to the ECU 1, and an actuator (not shown) (for example, a solenoid) provided in the brake fluid pressure control device BPC is driven based on a brake control signal from the ECU 1. Thus, the wheel cylinder pressure is adjusted.

  The various sensor groups include wheel speed sensors WS1 to WS4, a brake switch sensor BS, a throttle sensor TS, and an engine speed sensor ER in addition to the sensors described above.

  Wheel speed sensors WS1 to WS4 are disposed on the wheels FL, FR, RL, and RR. These wheel speed sensors WS1 to WS4 are connected to the ECU 1 and output to the ECU 1 a pulse signal having a pulse number proportional to the rotational speed of each wheel, that is, the wheel speed.

  The brake switch sensor BS detects that the driver has depressed the brake pedal BP. A detection signal from the brake switch sensor BS is input to the ECU 1.

  The throttle sensor TS detects the throttle opening of the main throttle valve MT and the sub-throttle valve ST while detecting whether the engine is in the idle range or the output range. From the throttle sensor TS, an idle switch signal indicating whether the engine is in an idle range or an output range, and throttle opening signals of the throttle valves MT and ST are output, and these signals are output to the ECU 1. It is like that. Based on the idle switch signal of the throttle sensor TS, the operation or non-operation of the accelerator pedal AP can be detected.

  The engine speed sensor ER is for detecting the engine speed. The engine speed is a parameter of the engine torque, and an engine torque curve corresponding to the engine speed is determined for each type of engine EG.

  The ECU 1 has a microcomputer CMP. The microcomputer CMP includes an input port IPT, an output port OPT, a processing unit CPU, ROM 2 and RAM 3 serving as storage means, control timers and counters (not shown), and these components are connected to each other via a bus. It has become.

  Output signals from the wheel speed sensors WS1 to WS4 and the brake switch BS described above are input from the input port IPT to the processing unit CPU via the amplifier circuit AMP. Further, control signals are output from the output port OPT to the throttle control device TH and the brake hydraulic pressure control device BPC via the drive circuit ACT.

  The ROM 2 stores a program for executing traction control. The processing unit CPU executes processing in accordance with a program stored in the ROM 2 while an ignition switch (not shown) is turned on, and the RAM 3 temporarily stores variable data necessary for execution of the program. Is memorized.

  The traction control process is executed by the control system configured as described above. The traction control process is executed by the ECU 1 and is executed using various calculated values calculated by a process different from the traction control process executed in the ECU 1. Since various calculation values used in this traction control process are well known in engine control and the like, the detailed description thereof will be omitted.

  FIG. 2 shows a flowchart of the traction control process. Each process shown in the flowchart of this traction control is executed when the ignition switch is turned on and the microcomputer is activated, and is executed for each drive wheel RL, RR.

  First, in step 100, wheel vibration determination and wheel acceleration maximum value storage processing are executed. Details of the wheel vibration determination and wheel acceleration maximum value storage processing are shown in the flowchart of FIG. With reference to this figure, the wheel vibration determination and the wheel acceleration maximum value storage processing will be described.

In step 102, it is determined whether or not the wheel acceleration DVW ** of each drive wheel exceeds a preset vibration determination acceleration reference K-DP. The vibration determination acceleration reference K-DP here is set as a determination threshold at which the value of the wheel acceleration DVW ** is assumed to cause the occurrence of wheel vibration due to slip. Of these, the part that executes this step corresponds to the vibration degree detecting means of the present invention. Here, the vibration determination acceleration reference K-DP is set as a determination threshold when the wheel acceleration DVW ** changes to the + side, and is set to 30 m / s ² , for example.

  If an affirmative determination is made in this step, it is assumed that wheel vibration due to slip has occurred, and the routine proceeds to step 104. In step 104, a flag F-PLG ** indicating that there is + wheel acceleration experience is set (ON) for the corresponding wheel, and an elapsed time C-UKDP ** from the + wheel acceleration experience is set. It is measured by a counter.

  Then, the process proceeds to step 106, where it is determined whether or not the value currently stored as the driving wheel wheel acceleration maximum value M-DVW-PLAS ** is smaller than the wheel acceleration DVW ** obtained this time for the corresponding wheel. Is done. If an affirmative determination is made here, the routine proceeds to step 108 where the value currently stored as the drive wheel wheel acceleration maximum value M-DVW-PLAS ** is rewritten to the wheel acceleration DVW ** obtained this time. Further, when a negative determination is made, the value currently stored as the driving wheel wheel acceleration maximum value M-DVW-PLAS ** is maintained.

  On the other hand, if a negative determination is made in step 102, the process proceeds to step 110. In step 110, it is determined whether or not the elapsed time C-UKDP ** from the + -side acceleration experience stored in the counter is shorter than the determination criterion K-UPDP without wheel vibration for the corresponding wheel. That is, it is considered that there is no vibration of the wheel when the wheel acceleration DVW ** described above falls below the preset vibration determination acceleration standard K-DP exceeds the wheel vibration determination criterion K-UPDP.

  For this reason, if an affirmative determination is made in this step, it is assumed that the vibration of the wheel may not have disappeared yet, the process proceeds to step 112, and the counter value is incremented by one, and from the + side acceleration experience. The elapsed time C-UKDP ** is increased.

  If a negative determination is made in this step, it is assumed that there is no longer any wheel vibration, and the routine proceeds to step 114. In step 114, the flag F-PLG ** indicating that there is + -side wheel acceleration experience is reset (OFF) for the corresponding wheel, and the driving wheel wheel acceleration maximum value M-DVW-PLAS ** is displayed. The currently stored value is set to 0, the wheel vibration determination flag F-SINDO ** is reset (OFF), and the vibration determination counter is reset to 0.

Subsequently, the routine proceeds to step 116, where it is determined whether or not the wheel acceleration DVW ** of each drive wheel is lower than a preset vibration determination acceleration reference K-DM. The vibration determination acceleration reference K-DM here is set as a determination threshold value at which the value of the wheel acceleration DVW ** is assumed to be the occurrence of wheel vibration due to slip. Here, the vibration determination acceleration reference K-DM is set as a determination threshold when the wheel acceleration DVW ** is changed to the − side, and is set to −30 m / s ² , for example.

  If an affirmative determination is made in this step, it is assumed that wheel vibration due to slip has occurred, and the routine proceeds to step 118. Then, in step 118, it is determined whether or not the flag F-PLG ** indicating that there is + wheel acceleration has been reset (OFF) for the corresponding wheel. If the determination is affirmative, the present process is terminated without executing the subsequent processes.

  That is, in step 118, if the flag F-PLG ** indicating that there is + wheel acceleration is not set in step 104, the subsequent processing is executed even if the determination in step 116 is affirmative. The subsequent processing is executed only when the flag F-PLG indicating that there is + wheel acceleration is set. However, when the wheel is vibrated, the wheel acceleration DVW ** exceeds the vibration determination acceleration criteria K-DP and K-DM on both the + side and the-side, and therefore triggers when the wheel acceleration DVW ** exceeds the + side. As a result, the processing after step 118 is executed for the first time.

  If a negative determination is made in step 118, the process proceeds to step 120, in which it is determined whether or not the corresponding wheel vibration determination counter C-SINDO ** is smaller than the vibration determination value K-SINDO. The vibration determination value K-SINDO here is set to the number of times that it may be detected that the vibration of the wheel is surely generated, and is set to about twice, for example.

  If an affirmative determination is made in this step, the vibration determination counter C-SINDO ** of the corresponding wheel is incremented by one, and a flag F-PLG ** indicating that there is + wheel acceleration is reset (OFF). Is done.

  If a negative determination is made in this step, the wheel vibration determination flag F-SINDO ** of the corresponding wheel is set (ON), and a flag F-PLG ** indicating that there is + wheel acceleration experience is set. Reset (OFF).

  When the wheel vibration determination and the wheel acceleration maximum value storage process are completed as described above, the process proceeds to step 200 shown in FIG.

  In step 200, it is determined whether vibration determination is performed. This is determined based on whether or not the wheel vibration determination flag F-SIODO of any wheel is set (ON). If an affirmative determination is made in this step, the process proceeds to step 300.

  In step 300, it is determined whether or not the previous vibration determination has been made. This is determined based on the wheel vibration determination flag F-SIODO-O that is the previous value of the wheel vibration determination flag F-SIODO described above, and is stored in step 500 described later.

  If an affirmative determination is made in this step, it is determined that the wheel vibration determination flag F-SIODO is set for the first time this time, and the process proceeds to step 400. Then, in step 400, an engine torque correction process when the wheel vibration determination is established is executed. A portion of the ECU 1 that executes this process corresponds to a reduction amount determination unit of the present invention.

  The details of this engine torque correction process are shown in the flowchart of FIG. With reference to this figure, the wheel vibration determination and the wheel acceleration maximum value storage processing will be described.

  In step 402, a reduced torque amount TRQDWN-SINDO is calculated based on the drive wheel wheel acceleration maximum value M-DVW-PLAS ** at the time of wheel vibration determination. The reduction torque amount TRQDWN-SINDO here indicates the reduction amount of the drive torque, and is obtained based on the correlation with the drive wheel wheel acceleration maximum value M-DVW-PLAS **. For example, FIG. Determined from the map shown.

  FIG. 5 is a map showing the correlation between the drive wheel wheel acceleration maximum value M-DVW-PLAS ** and the reduced torque amount TRQDWN-SINDO, which is obtained in advance through experiments, for example.

  As shown in this figure, the reduction torque amount TRQDWN-SINDO is set to increase as the drive wheel wheel acceleration maximum value M-DVW-PLAS ** increases. This is because the greater the wheel acceleration DVW ** when the wheel vibrates, the more torque reduction is required to converge the vibration earlier.

  Then, the process proceeds to step 404, and the finally required reduced torque amount TRQDWN is calculated. Specifically, a value obtained by multiplying the previous engine torque target value by a predetermined coefficient, for example, 30%, and the reduced torque amount TRQDWN-SINDO obtained in step 402 is the final reduced torque amount. TRQDWN.

  This is because when the torque reduction is increased, the vibration convergence of the wheel can be accelerated, but there is a contradiction that stalls. Therefore, in order to suppress this, the maximum value of the final reduced torque amount TRQDWN is limited. It is.

  For example, even if the fluctuations in wheel acceleration are the same, the relationship between the slip ratio and the road surface friction coefficient μ (μ-S characteristics) may differ depending on the road surface on which the vehicle is traveling. When the road surface on which the vehicle is traveling is road surface A and road surface B, the relationship between the slip ratio and the road surface friction coefficient μ is shown in FIG. In each of the road surfaces A and B, if the gradient in the vicinity of the μ peak, that is, the degree of decrease of μ after exceeding the μ peak is the same, the fluctuations in the wheel acceleration are predicted to be equal.

  However, even if the reduction amount of the engine torque target value obtained from the wheel acceleration is large and the reduction amount is subtracted from the engine torque target value in the case of the road surface A where the driving force is sufficiently large, the driver will not feel stalled. If the amount of reduction is subtracted from the target engine torque value for road surface B where the force is not sufficient, the driver will feel stalled.

  Therefore, as described above, the maximum value of the final reduced torque amount TRQDWN is limited to a value obtained by multiplying the previous engine torque target value by a predetermined coefficient to prevent the driver from feeling stalled. .

  When the final reduced torque amount TRQDWN is obtained, the process proceeds to step 406, and the engine torque target value is obtained. Specifically, the current engine torque target value is obtained by subtracting the reduced torque amount TRQDWN from the previous engine torque target value.

  In this way, when the engine torque correction process is completed when the wheel vibration determination is established, the routine proceeds to step 500 shown in FIG. In step 500, the current wheel vibration determination flag F-SIODO is stored as the wheel vibration determination flag F-SIODO-O, which is the previous value of the wheel vibration determination flag F-SIODO. Each process as described above is repeatedly executed every predetermined calculation cycle.

  When the engine torque target value is corrected, an engine control signal corresponding to the correction result is output from the ECU 1, and the drive torque is controlled so as to be the engine torque target value. The portion of the ECU 1 that executes this processing corresponds to the drive torque control means of the present invention.

  FIG. 7 is a timing chart when the traction control shown in the present embodiment is executed. FIG. 7A shows the relationship between the drive wheel speed and the wheel speed, FIG. 7B shows the change in the drive wheel acceleration, and FIG. 7C shows the vibration determination. FIG. 7D shows the state of the wheel vibration determination flag F-SIODO-O at the time, and shows the fluctuation of the engine torque target value.

  As shown in these figures, when vibration is generated and the drive wheel speed changes so as to swing with respect to the vehicle body speed due to the vibration, the drive wheel acceleration changes according to the swing. When the driving wheel acceleration exceeds the vibration determination acceleration criteria K-DP, K-DM, it is determined that wheel vibration has occurred, and the wheel vibration determination flag F-SIODO-O is set. At this moment, the engine torque target value is set to a value decreased by a predetermined amount from before the determination.

  As described above, in the traction control device of this embodiment, when wheel vibration occurs, the engine torque target value is set to a value that is reduced by a predetermined amount compared to before the wheel vibration occurs. That is, it is determined that the wheel vibration has occurred, and at the same time, the engine torque target value is lowered to a region where the wheel vibration does not occur. For this reason, it becomes possible to converge wheel vibration more quickly.

  Then, the reduction amount of the engine torque target value is obtained based on the maximum value of the wheel acceleration when the wheel vibration occurs. That is, the reduction amount of the engine torque target value is obtained based on the wheel acceleration whose magnitude varies according to the magnitude of the wheel vibration. For this reason, it is possible to accurately obtain the reduction amount of the engine torque target value necessary for making the region in which no wheel vibration occurs.

  The wheel acceleration and the reduction amount of the engine torque target value are previously set as a map, and the reduction amount of the engine torque target value is obtained using the map. For this reason, compared with the case where an engine torque target value is calculated | required by calculation, the processing burden in ECU1 can be reduced. Further, when the map is used in this way, the following effects are obtained.

  For example, the road surface B and the road surface C are assumed as the traveling road surface of the vehicle when the traction control is executed, and the relationship (μ-S characteristic) between the slip ratio and the road surface friction coefficient μ on each of the road surfaces B and C is as follows. Suppose that it is shown as in FIG.

  In such a case, as compared with the road surface C, the road surface B has a larger magnitude of wheel vibration, that is, the vibration level. In order to suppress such wheel vibration, it is necessary to reduce the drive torque to the point before the μ peak, and the engine torque target value is reduced so as to achieve such a drive torque.

  In this case, the wheel vibration can be attenuated even if the engine torque target value is reduced until the slip ratio reaches the point a in the figure, but the convergence is delayed. Further, when the engine torque target value is reduced until reaching point c in the figure, the wheel vibration can be attenuated quickly, but there is a sense of stalling of the vehicle speed, which may cause the driver to feel rattling.

  Therefore, the wheel acceleration during wheel vibration and the reduction amount of the engine torque target value are correlated. However, since these correlations are not completely proportional, it is possible to determine the reduction amount of the engine torque target value more accurately by using a map than by approximation by calculation.

(Other embodiments)
In the above embodiment, the reduction amount of the engine torque target value is set using a map, but it is of course possible to obtain it by calculation. For example, when the inertia is I, the wheel acceleration is ω ′, the tire torque is T _T , and the drive torque is Td, the following relationship is established.

(Equation 1)
Iω ′ = (T _T −Td)
Therefore, ω ′ is expressed as the following equation, and the tire torque T _T is μ × m × g (where μ is a road surface friction coefficient, m is a vehicle weight, and g is a gravitational acceleration). The driving torque according to the wheel acceleration, that is, the engine torque target value necessary for obtaining the driving torque can be obtained, and the reduction amount can be obtained.

(Equation 2)
ω ′ = (T _T −Td) / I
However, when the reduction amount of the engine torque target value is obtained by such calculation, it is preferable to use the map rather than the calculation because the above-described effect cannot be obtained compared to the case of obtaining by the map.

  In the first embodiment, the wheel acceleration is used to detect the degree of vibration of the vehicle. However, it is also possible to use the wheel speed amplitude. Also in this case, if the reduction amount of the engine torque target value is obtained based on the maximum value of the wheel speed amplitude, the reduction amount can be obtained more accurately. In this case as well, if the relationship between the maximum value of the wheel speed amplitude and the reduction amount of the engine torque target value is mapped, the same effect as in the above embodiment can be obtained.

  The steps shown in each figure correspond to means for executing various processes.

It is a figure showing the whole vehicle control system composition which realized the traction control device concerning one embodiment of the present invention. It is a flowchart of a traction control process. It is a flowchart which shows the detail of a wheel vibration determination and a wheel acceleration maximum value memory | storage process. It is a flowchart which shows the detail of an engine torque correction process. It is the map which showed the correlation with driving wheel wheel acceleration maximum value M-DVW-PLAS ** and reduction torque amount TRQDWN-SINDO. It is the figure which showed the relationship between the slip ratio of each of the road surface A and the road surface B, and road surface friction coefficient (micro | micron | mu). It is a timing chart when traction control is performed. It is the figure which showed the relationship between the slip ratio in the road surfaces B and C, and the road surface friction coefficient (micro | micron | mu).

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... ECU, EG ... Engine, GS ... Transmission, BPC ... Brake fluid pressure control device, FL, FR, RL, RR ... Wheel, Wfl, Wfr, Wrl, Wrr ... Wheel cylinder, WS1-WS4 ... Wheel speed sensor, BS: Brake switch sensor, ST: Throttle sensor.

Claims (8)

Vibration degree detecting means for detecting the vibration degree of the wheel;
A reduction amount determination means for determining a reduction amount of the engine torque target value based on the vibration degree detected by the vibration degree detection means;
The reduction amount determining means subtracts the engine torque target value or these before the vibration by the vibration degree detecting means the reduction amount determined is detected by the drive torque so that the engine torque target value subtracted the Part And a drive torque control means for controlling the traction control device. 2. The traction control according to claim 1, wherein the vibration degree detection means includes means for detecting wheel acceleration, and detects the degree of vibration of the wheel based on the wheel acceleration obtained by the means. apparatus. The vibration degree detection means determines that wheel vibration has occurred based on the wheel acceleration,
The reduction amount determining means obtains a maximum value of the wheel acceleration when it is determined that the wheel vibration has occurred, from the wheel acceleration detected by the vibration degree detecting means, and from the maximum value of the wheel acceleration, the The traction control device according to claim 2, wherein a reduction amount of the engine torque target value is obtained. The reduction amount determination means stores a relationship between the wheel acceleration and the reduction amount of the engine torque target value as a map, and based on the map, the engine torque target value corresponding to the maximum value of the wheel acceleration is stored. The traction control device according to claim 3, wherein a reduction amount is obtained. The said vibration degree detection means has a means to detect the amplitude of a wheel speed, and detects the vibration degree of the said wheel based on the amplitude of the said wheel speed calculated | required by this means. The traction control device described. The vibration degree detection means determines that wheel vibration has occurred based on the amplitude of the wheel speed,
The reduction amount determining means obtains the maximum value of the wheel speed amplitude when it is determined that the wheel vibration has occurred, from the wheel speed amplitude detected by the vibration degree detecting means, 6. The traction control device according to claim 5, wherein a reduction amount of the engine torque target value is obtained from a maximum amplitude value. The reduction amount determining means stores a relationship between the amplitude of the wheel speed and the reduction amount of the engine torque target value as a map, and based on this map, the engine corresponding to the maximum value of the wheel speed amplitude. The traction control device according to claim 6, wherein a reduction amount of the torque target value is obtained. 8. The reduction amount determining means sets a value obtained by multiplying the engine torque target value by a predetermined coefficient as a maximum value of the reduction amount of the engine torque target value. The traction control device according to any one of the above.

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