JP3024138B2 - Vehicle acceleration slip control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acceleration slip control device for a vehicle that suppresses an acceleration slip generated on a drive wheel during vehicle acceleration.

2. Description of the Related Art Conventionally, an acceleration slip control device for a vehicle detects an acceleration slip of a drive wheel from a rotational speed of a drive wheel and a vehicle speed or a rotational acceleration of the drive wheel, and drives the drive wheel when the acceleration slip is detected. Control of the internal combustion engine to suppress the output torque of the internal combustion engine (ignition timing retard control, fuel cut control, throttle valve closing control, etc.), or braking by operating the brake device to apply a braking torque to the drive wheels By executing control and the like to reduce the rotational torque of the drive wheels, the acceleration slip of the drive wheels generated during vehicle acceleration is suppressed.

Further, in this type of apparatus, as described in Japanese Patent Application Laid-Open No. 60-128057, for example, an acceleration slip generated on the drive wheels is controlled so that the slip state of the drive wheels can be controlled to a target slip state in which the highest acceleration can be obtained. A slip amount (for example, a slip ratio) representing the magnitude is calculated, and the control amounts of the various controls are determined based on a deviation between the slip amount and a target slip amount representing the target slip state, thereby controlling the rotational torque of the drive wheels. Is being done.

[Problems to be Solved by the Invention] However, in this type of device, the rotational torque of the drive wheels is controlled by feedback control based on the difference between the slip amount of the drive wheels and the target slip amount. Is constant, the slip amount of the drive wheels can converge to the target slip amount.However, if the road surface condition changes during control, the control becomes unstable, and the rotational torque of the driving forest is excessively suppressed, and the acceleration performance is reduced. On the contrary, there is a problem that the rotational torque of the drive wheels cannot be controlled well and a large acceleration slip occurs again.

In other words, during the acceleration slip control, the vehicle travels from a road (high μ road) where asphalt road or the like has a high road friction coefficient μ (hereinafter simply referred to as road surface μ) and slip is unlikely to occur.
Roads with low surface μ such as snowy roads where slipping is likely to occur (low μ
Road), the rotational torque of the drive wheel corresponding to the high μ road that has been controlled so far becomes too large for the low μ road, and a large acceleration slip occurs again in the drive wheel. If the vehicle travel path changes from a low μ road to a high μ road during control, on the low μ road, the vehicle is driven to a sufficiently low level that no slip occurs on the high μ road. Because the rotational torque of the wheel is suppressed,
On a high μ road, there is a problem that the rotational torque of the drive wheels is too low, and optimal acceleration cannot be obtained.

Therefore, an object of the present invention is to provide an acceleration slip control device that can achieve optimum acceleration while suppressing acceleration slip even when the road surface μ changes during the acceleration slip control as described above.

[Means for Solving the Problems] That is, the present invention, which has been made to achieve the above object, has a first aspect.
As illustrated in the figure, a drive wheel speed detecting means M2 for detecting the rotational speed of the drive wheel M1
A slip amount calculating means M3 for calculating a slip amount representing a magnitude of a slip generated on the drive wheel during vehicle acceleration, using the detected rotation speed of the drive wheel M1 as one parameter.
Acceleration slip detecting means M4 for detecting an acceleration slip of the drive wheel M1 based on the calculated slip amount; and when the acceleration slip of the drive wheel M1 is detected by the acceleration slip detection means M4, the slip amount is previously determined. An acceleration slip control means M5 for controlling the rotational torque of the drive wheel M1 so as to achieve the set target slip amount.In a vehicle acceleration slip control device comprising: a vehicle acceleration detection means M6 for detecting the acceleration of the vehicle
A road surface that identifies which of a plurality of road surface conditions the vehicle traveling road surface is classified in advance based on the road surface friction coefficient based on the detected vehicle acceleration and the slip amount of the drive wheel M1. Based on the identification result of the state identification means M7 and the road surface state identification means M7, it is determined whether or not the vehicle traveling road surface has changed from a road surface having a high road surface friction coefficient to a road surface having a low road surface friction coefficient or in the opposite direction. When the vehicle running road surface is determined to have changed to a road surface having a low road surface friction coefficient by the road surface change determining unit M8, the control amount by the acceleration slip control unit M5 is changed to the drive wheel M1. When the vehicle running road surface is determined to have changed to a road surface having a high road surface friction coefficient, the control amount by the acceleration slip control means M5 is changed to the rotational torque of the driving wheel M1. Suppression A control amount changing means M9 for changing the direction of reducing the slip amount of the drive wheel M1 is, when previously smaller than the first criterion slip amount set, the control amount changing means
The change of the control amount in the direction of suppressing the rotational torque of the drive wheel M1 by M9 is prohibited, and when the slip amount of the drive wheel M1 is larger than a second reference slip amount set in advance, the control amount change is performed. A change prohibition means M10 for prohibiting a change in the control amount in a direction to reduce the suppression of the rotational torque of the drive wheel M1 by the means M9. .

[Operation] In the acceleration slip control device of the present invention configured as described above, first, the driving wheel speed detecting means M2 detects the rotation speed of the driving wheel M1. Then, the slip amount calculation means M3 calculates the slip amount of the drive wheel M1 using the detected rotation speed of the drive wheel as one parameter, and calculates the acceleration slip detection means M4.
Detects the acceleration slip of the drive wheel M1 based on the calculated slip amount. Further, when the acceleration slip detecting means M4 detects the acceleration slip of the drive wheel M1, the acceleration slip control means M5 operates to reduce the rotational torque of the drive wheel M1 so that the slip amount of the drive wheel M1 becomes a predetermined target slip amount. Control.

Further, in the present invention, the vehicle acceleration detecting means M6 detects the acceleration of the vehicle, and the road surface state identifying means M7 is based on the detected vehicle acceleration and the slip amount of the drive wheel M1 calculated by the slip amount calculating means M3. , The traveling road surface of the vehicle,
One of a plurality of road surface states classified in advance according to the road surface friction coefficient is identified. Then, based on the identification result of the road surface state identification unit M7, the road surface change determination unit M8 determines whether the vehicle traveling road surface has changed from a road surface with a high road surface friction coefficient to a road surface with a low road surface friction coefficient or in the opposite direction. Judge. When the road surface change determining unit M8 determines that the vehicle traveling road surface has changed to a road surface having a low road surface friction coefficient, the control amount changing unit M9 changes the control amount by the acceleration slip control unit M5 to the drive wheel M1. Is changed in a direction to further suppress the rotation torque. When the road surface change determining unit M8 determines that the vehicle traveling road surface has changed to a road surface having a high road surface friction coefficient, the control amount changing unit M9 changes the control amount by the acceleration slip control unit M5 to the drive wheel M1. In a direction that reduces the suppression of the rotational torque of the motor.

When the slip amount of the drive wheel M1 is smaller than the first reference slip amount set in advance, the change prohibition unit M10 controls the control amount by the control amount change unit M9 in the direction to suppress the rotational torque of the drive wheel M1. Is prohibited, and when the slip amount of the drive wheel M1 is larger than the second reference slip amount set in advance, the control amount in the direction of reducing the suppression of the rotational torque of the drive wheel M1 by the control amount changing means M9. Prohibit the change of.

That is, in the present invention, when an acceleration slip occurs in the drive wheel M1, not only the rotational torque of the drive wheel M1 is controlled so that the slip amount of the drive wheel M1 becomes the target slip amount, but also the slip amount of the drive wheel M1 is controlled. Based on the vehicle acceleration and the vehicle acceleration, the traveling road surface of the vehicle is identified as one of a plurality of road surface conditions classified according to the road surface friction coefficient, and when the road surface condition changes, that is, the vehicle traveling road is When the road changes from a low μ road to a high μ road or vice versa, the control amount is changed according to the change. In addition, the change of the control amount according to the change of the road surface condition is prohibited according to the magnitude of the slip amount.

As a result, when an acceleration slip occurs in the drive wheel M1, the rotational torque of the drive wheel M1 can be controlled so as to obtain optimum acceleration while suppressing the acceleration slip, and the road surface is controlled during the control. If the state changes, drive wheels
It is possible to quickly change the rotational torque of M1 to an optimal value according to the road surface condition.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

First, FIG. 2 is a schematic configuration diagram showing an entire configuration of an acceleration slip control device of an embodiment in which the present invention is applied to a front engine / rear drive (FR) type vehicle using an internal combustion engine 2 as a power source.

As shown in the figure, a surge tank 4a for suppressing pulsation of intake air is formed in an intake passage 4 of the internal combustion engine 2, and a main slot valve 8 opened and closed in conjunction with an accelerator pedal 6 and a main slot valve are provided upstream thereof. Drive motor upstream of valve 8
And a sub-throttle valve 12 which is opened and closed by 10. The main throttle valve 8 and the sub-throttle valve 12 are provided with a main throttle opening sensor 14 and a sub-throttle opening sensor 16 for detecting the openings θM and θS, respectively. The detection signals from these sensors are It is input to the acceleration slip control circuit 20.

The acceleration slip control circuit 20 includes a left and right driving wheel (rear wheel) 22R.
Detects acceleration slip generated on L, 22RR,
The output torque of the internal combustion engine 2 is controlled by opening and closing the sub-throttle valve 12 via the ECU, and the control of the output torque due to the opening and closing control of the sub-throttle valve 12 immediately after the detection of the acceleration slip is compensated. In addition, depending on the operation state of the internal combustion engine 2, the fuel injection valve 24
Well-known internal combustion engine control circuit 26 for controlling the fuel injection amount from the engine
, A fuel cut (hereinafter also referred to as F / C) command signal is temporarily output to execute the F / C control for stopping the fuel injection from the fuel injection valve 24. The internal combustion engine control circuit 2
6 is designed to stop the fuel injection from the fuel injection valve 24 while the F / C command signal from the acceleration slip control circuit 20 is being input. The output torque of the internal combustion engine 2 is controlled by this F / C control. Decreases rapidly.

In addition, detection signals from various sensors for detecting the running state of the vehicle are input to the acceleration slip control circuit 20 in order to perform such acceleration slip control.

That is, the acceleration slip control device includes, as sensors for detecting the running state of the vehicle, a rotation speed sensor 30 for detecting a rotation speed NE of the internal combustion engine 2 and left and right driven wheels (front wheels) 22FL, 2FL.
Left and right driven wheel speed sensors 32FL and 32FR that detect the rotational speed (followed wheel speed) VFL and VFR of 2FR, and left and right drive wheels 22RL and 22
Drive wheel speed sensors 32RL and 32RR for detecting the rotational speeds (drive wheel speeds) VRL and VRR of RR are provided, and detection signals from these sensors are input to the acceleration slip control circuit 20.

The rotation of the internal combustion engine 2 is applied to the left and right drive wheels 22RL and 22RR.
In the present embodiment, the output torque of the internal combustion engine 2 is controlled by the acceleration slip control circuit 20 as described above, since the transmission torque is transmitted through the transmission 34, the propeller shaft 36, and the differential gear 38. The rotation torque of 22RL and 22RR is controlled.

Next, the acceleration slip control circuit 20, as shown in FIG.
The CPU 20a, the ROM 20b, the RAM 20c, the backup RAM 20d, the input / output port 20e, and a logical operation circuit centered on a common bus 20f connecting these components.The rotational speed sensor 30, the left and right driven wheel speed sensors among the above-described sensors. 32FL, 3
The detection signals from the 2FR and the left and right drive wheel speed sensors 32RL and 32RR are passed through a waveform shaping circuit 20g, and the detection signals from the main throttle opening sensor 14 and the sub throttle opening sensor 16 are sent to the A / D converter 20h. Through the input / output port 20e. The input / output port 20e outputs an F / C command signal to the drive circuit 20i for driving the drive motor 10 to control the sub-throttle valve 12 to the target opening θS0, and to the internal combustion engine control circuit 26 to output the F / C command signal. An F / C command signal output circuit 20j for executing the / C control is connected, and the opening and closing control of the sub-throttle valve 12 and the F / C control of the internal combustion engine 2 can be executed through these units. I have.

Hereinafter, the acceleration slip control circuit 20 configured as described above will be described.
Fig. 4 to Fig. 10
This will be described in detail with reference to the flowchart shown in FIG.

First, FIG. 4 is a flowchart showing a slip ratio calculation process for calculating a slip ratio of a drive wheel. This process is repeatedly executed after the start of the internal combustion engine 2. First, in step 100, based on the detection signals from the left and right driven wheel speed sensors 32FL and 32FR, the average rotational speed of the left and right driven wheels 22FL and 22FR (VFL + VFR) / 2｝ is calculated as the vehicle speed VF, and in the next step 110, the left and right driving wheel speed sensors 32RL,
Based on the detection signal from the 32RR, a process is performed as a drive wheel speed detecting means M2 for calculating an average rotational speed {= (VRL + VRR) / 2} of the left and right drive wheels 22RL, 22RR as a drive wheel speed VR, and then, at step 120 , The calculated vehicle speed VF
And the driving wheel speed VR, the following formula (1) is used to execute a process as a slip amount calculating means M3 for calculating a slip ratio SLP of the driving wheels.

SLP = (VR−VF) / VR (1) Next, FIG. 5 determines whether or not an acceleration slip has occurred in the driving wheel based on the slip ratio SLP calculated in the slip ratio calculation process. 9 is a flowchart illustrating an acceleration slip control process for controlling the output torque of the internal combustion engine 2 so that the slip ratio SLP of the drive wheels becomes the target slip ratio SLPO when an acceleration slip occurs.

This process is executed as an interrupt process every predetermined time (for example, every 5 msec.) After the start of the internal combustion engine 2. When the process is started, first, step 200 is executed, and the main throttle valve 8 is started. It is determined whether an execution condition of the acceleration slip control such as not being in the fully closed state is satisfied. If the execution condition of the acceleration slip control is not satisfied, the process proceeds to step 205, where the counter CEND and the flags FS, FCUT for executing the acceleration slip control are reset, and the driving of the sub-throttle valve 12 controlled by the drive circuit 20i. The maximum opening θSmax of the sub-throttle valve 12 is set as a target opening degree (hereinafter referred to as a target sub-throttle opening degree) θS0, and is used to identify the road surface μ immediately after the start of the acceleration slip control in a first μ determination process described later. Flags FADD, FEN
Is reset, and the process is temporarily terminated.

On the other hand, if it is determined in step 200 that the execution condition of the acceleration slip control is satisfied, the process proceeds to step 210, where the slip ratio SL calculated in the slip ratio calculation process is calculated.
Calculate a deviation ΔS between P and a target slip ratio SLPO (for example, 0.2) set in advance so as to obtain optimal acceleration,
Move to step 215.

In step 215, it is determined whether or not a control execution flag FS set at the start of the execution of the acceleration slip control in a process described later is in a set state, that is, whether or not the acceleration slip control is currently being executed. If the flag FS is in the reset state and the acceleration slip control has not been executed, the process proceeds to step 220. In step 220, it is determined whether or not the acceleration slip has occurred in the drive wheel depending on whether the deviation ΔS obtained in step 210 is a positive value, that is, whether the slip ratio SLP of the drive wheel is greater than the target slip ratio SLPO. A process as acceleration slip detecting means M4 for determining whether or not the determination is performed is executed. If it is determined in step 220 that the deviation ΔS is not a positive value, the process proceeds to step 205 assuming that no acceleration slip has occurred in the driving wheels.

On the other hand, if it is determined in step 220 that the deviation ΔS is a positive value, it is determined that an acceleration slip has occurred in the driving wheels, and the flow shifts to step 225 to set the control execution flag FS.
In a subsequent step 230, a μ determination execution flag FEN used in a first μ determination process described later is set, and in a subsequent step 235, the target sub-throttle opening θS0 at the start of control is set.
The control start throttle opening θSEN calculated in the control start throttle opening calculation process described later is set. Then, in the subsequent step 240, an output command of the F / C command signal is issued to the F / C command signal output circuit 20j, and F
The / C control execution flag FCUT is set, and the process ends once.

By executing the process of step 240, the F / C
F from the command signal output circuit 20j to the internal combustion engine control circuit 26
/ C command signal is output. Then, the internal combustion engine control circuit 26
Receives the F / C command signal, and starts F / C control for stopping fuel injection from the fuel injection valve 24.

Next, in step 215, if it is determined that the control execution flag FS is in the set state and the acceleration slip control is currently being executed, the process proceeds to step 245, where the F / C control execution flag FCUT is reset. Status, that is, the current F /
It is determined whether the C control is not being executed. And F / C
If the control execution flag FCUT is set and the F / C control is currently being executed, the process proceeds to step 250,
The rotational speed NE of the internal combustion engine 2 is determined based on the detection signal from the rotational speed sensor 30, and a deviation ΔNE (= NE) between the rotational speed NE and the rotational speed NEn-1 obtained when the process is executed last time.
-NEn-1) is calculated as the rotational acceleration of the internal combustion engine 2,
Move to step 255.

In step 255, it is determined whether or not the calculated rotational acceleration ΔNE of the internal combustion engine 2 is equal to or less than a predetermined value K1 (for example, 0). If ΔNE ≦ K1, the process proceeds to step 260, where F
/ F Stops the output of the F / C command signal from the command signal output circuit 20j and resets the F / C control execution flag FCUT, and then proceeds to step 265. Conversely, if ΔNE> K1, then directly proceeds to step 265. Transition.

Note that the processing in steps 250 to 260 executes the F / C control until the rotational acceleration ΔNE of the internal combustion engine 2 becomes equal to or less than K1 after the start of the acceleration slip control. This is a process for quickly reducing the output torque, and when the output of the F / C command signal from the F / C command signal output circuit 20j is stopped by the process of Step 260,
The internal combustion engine control circuit 26 ends the F / C control and restarts the normal fuel injection control.

Next, step 265 is a process which is also executed when it is determined in step 245 that the F / C control execution flag FCUT is in the reset state. The deviation ΔS obtained in step 210 and its differential value Δ The following equation (2) is used to calculate the control amount ΔθS of the sub-throttle valve 12 using the following equation (2) (where β1, β2 is a proportional constant). Then, in the subsequent step 270, the target sub-throttle opening θS0 is updated by subtracting the control amount ΔθS obtained in step 265 from the target sub-throttle opening θS0 set in the previous execution of the process, and the process proceeds to step 275. I do.

Step 270 (step 235 immediately after the start of control)
The target sub-throttle opening θS0 set in the above is output to the drive circuit 20i as a control signal for the drive motor 10, and is used to control the sub-throttle valve 12 to the target sub-throttle opening θS0 via the drive motor 10. You.

Next, at step 275, it is determined whether or not the updated target sub-throttle opening θS0 has exceeded the main throttle opening θM. If θS0> θM, the process proceeds to step 280, where a counter CE for measuring the state of θSO> θM is clocked.
ND is incremented, and the routine goes to step 285. Conversely, if θS0 ≦ θM, the routine goes to step 290 to set the counter C
After resetting END, the process is temporarily terminated.

In step 285, it is determined whether or not the value of the counter CEND has exceeded a predetermined value K2, that is, whether or not the state of θS0> θM has passed for a predetermined time or more. Otherwise, it is determined that there is no longer any acceleration slip on the drive wheels, and the routine proceeds to step 205.

As described above, in the acceleration slip control process of FIG. 5, the acceleration slip is detected based on the slip ratio SLP of the drive wheels and the target slip ratio SLPO, and after the detection of the acceleration slip, the rotational acceleration ΔNE of the internal combustion engine becomes equal to or less than a predetermined value K1. Until the above, the F / C control and the opening / closing control of the sub-throttle valve 12 are simultaneously performed, and thereafter, the opening / closing control of the sub-throttle valve 12 is executed until the acceleration slip does not occur. As a result, immediately after the occurrence of the acceleration slip, the output torque of the internal combustion engine 2 is rapidly reduced by the F / C control, and by the subsequent opening and closing control of the sub-throttle valve 12, the slip ratio SLP of the drive wheel becomes equal to the target slip ratio SLPO. Thus, the output torque of the internal combustion engine 2 is controlled. In this embodiment, a series of processing executed for the acceleration slip control in the acceleration slip control processing corresponds to the above-described acceleration slip control means M5.

Next, FIG. 6 shows, based on the slip state of the drive wheels immediately after the start of the acceleration slip control, a first μ for identifying whether the road surface μ is a preset low μ, medium μ, or high μ.
It is a flowchart showing a determination process.

This process is executed as an interrupt process at predetermined time intervals (for example, 5 msec.) After the start of the internal combustion engine 2 in the same manner as the above-described acceleration slip control process. In the acceleration slip control process, it is determined whether or not the μ determination execution flag FEN set immediately after the detection of the acceleration slip is in a set state.

Then, if it is determined in step 300 that the μ determination flag FEN is in the reset state, the process ends, and
When it is determined that the μ determination flag FEN is in the set state,
The process proceeds to step 305 to determine whether the flag FADD is set. This flag FADD is a flag that is reset when the acceleration slip control is not executed by the initialization processing of step 205 executed in the acceleration slip control processing, and thus is in a reset state immediately after the start of the acceleration slip control. If this step 305 is executed for the first time after the start of the acceleration slip control, a negative determination is made in step 305, and the routine proceeds to step 310.

In step 310, it is determined whether or not the slip ratio SLP of the drive wheel calculated in the slip ratio calculation process is equal to or greater than a preset reference slip ratio KSLPO. In this step 310, the slip rate SLP is changed to the reference slip rate KSLP
If it is determined that it is smaller than O, the process is terminated as it is, and when the slip ratio SLP is equal to or more than the reference slip ratio KSLPO, the process proceeds to step 315.

The reference slip ratio KSLPO is set to a value larger than the target slip ratio SKPO for the acceleration slip control.

In step 315, the flag FADD is set, and the process proceeds to step 320, where the integrated value ス リ ッ プ SLP1 of the slip ratio SLP updated in the subsequent processing is initialized to 0, and the counter CMYU1 is reset in the next step 325. I do. In the following step 330, a process of adding the slip ratio SLP to the initially set integrated value ΣSLP1 is performed, and in a subsequent step 335, a process of incrementing the counter CMYU1 is performed, and the process is temporarily terminated. .

Next, at step 305, when it is determined that the flag FADD is in the set state, that is, when the slip rate SLP is equal to or higher than the reference slip rate KSLPO after the start of the acceleration slip control, and the flag FADD is already set at step 315. In
The routine proceeds to step 340, where it is determined whether the F / C control execution flag FCUT set / reset in the acceleration slip control process is in a set state, that is, whether the F / C control is being executed.

Then, at step 340, when it is determined that the F / C control is being executed with the F / C control execution flag FCUT set,
In step 330, the current slip ratio SLP is added to the integrated value ΣSLP1, and in step 335, the counter CMYU1 is incremented, and the process is temporarily terminated.

On the other hand, if it is determined in step 340 that the F / C control execution flag is in the reset state and the F / C control has been completed, the process proceeds to step 345, where the integrated value ΣSLP1 is divided by the value of the counter CMYU1. , The slip rate SLP is the reference slip rate KSL
After reaching PO or more, the average slip ratio ▲ ▼ is calculated until the F / C control ends.

In the following step 350, it is determined whether or not the calculated average slip ratio ▼ is equal to or higher than a predetermined high μ determination reference slip ratio KSLPH. And ▲
▼ <KSLPH, the road surface μ is determined to be high μ, the process proceeds to step 355, high μ is set to μ data MYULVL representing the road surface μ, and the μ determination execution flag FEN is reset in step 360. finish.

On the other hand, if it is determined in step 350 that ▲ ▼ ≧ KSLPH, the process proceeds to step 365, in which the average slip ratio ▲ ▼ is changed to the reference slip ratio KSLPL for low μ determination.
It is determined whether or not this is the case. If ▲ ▼ ≧ KSLPL, it is determined that the road surface μ is low μ, and the flow shifts to step 370 to set low μ in the μ data MYULVL, and conversely ▲
If ▼ <KSLPL, it is determined that the road surface μ is medium μ, and the flow shifts to step 375 to set medium μ in the μ data MYULVL. When the low μ or the medium μ is set in the μ data MYULVL in this way, the process proceeds to step 360, and after resetting the μ determination execution flag FEN, the process is temporarily terminated.

As described above, in the first μ determination process, after the acceleration slip is generated in the driving wheel and the acceleration slip control is started, the slip ratio SLP of the driving wheel temporarily exceeds the reference slip ratio KSLPO, and then the internal combustion engine is controlled by the F / C control. The road surface μ is low μ, medium μ based on the average slip ratio ▲ ▼ until the output torque of the engine 2 decreases and the rotational acceleration ΔNE of the internal combustion engine 2 falls below the predetermined value K1 and the F / C control ends. , High μ. That is, in the first μ determination process, every time the acceleration slip control is executed, the road μ is determined only once based on the slip ratio of the drive wheels immediately after the start of the control.
Is to be identified.

The reason why the road surface μ can be determined from the average slip ratio ▲ ▼ immediately after the start of the acceleration slip control as described above is that the lower the road surface μ, the more slip occurs in the drive wheels. That is, the average slip ratio ▼ calculated in step 345 changes according to the road surface μ, and the lower the road surface μ, the larger the average slip ratio ▲ ▼. ▲
The road surface μ is identified from the size of ▼.

Next, FIG. 7 shows the road surface state identification means M7 for identifying the road surface μ based on the vehicle acceleration and the slip ratio of the drive wheels.
13 is a flowchart illustrating a second μ determination process as in FIG.

This processing is performed for a predetermined time (for example, 5 m) after the internal combustion engine 2 is started, similarly to the acceleration slip control processing and the first μ determination processing described above.
sec.) is executed as an interruption process. When the process is started, first, step 400 is executed to determine whether or not the vehicle speed VF calculated in the slip ratio calculation process is 0 or less, that is, Determine whether or not it is stopped.

When it is determined in step 400 that the vehicle is stopped at a vehicle speed VF of 0 or less, the process proceeds to step 405, and a counter for determining a road surface μ used in a process described below.
Reset CMYUL, CMYUM, and CMYUH. In step 410, the counter CMYU2 for detecting vehicle acceleration used in the processing described later is reset, and the slip ratio SLP
Initialize the integrated value ΣSLP2 of the
Then, a value (= VF + 1.25) obtained by adding a predetermined value (1.25 km / h in this embodiment) to the vehicle speed VF is set, and the process is temporarily terminated.

On the other hand, if it is determined in step 400 that the vehicle speed VF exceeds 0, the process proceeds to step 420, where the vehicle speed VF
Is determined to be equal to or higher than the reference speed KVF set in step 410 described above. And the body speed VF is the reference speed
If it is smaller than KVF, the process proceeds to the subsequent step 425, where the counter CMYU2 is incremented. In the subsequent step 430, the slip ratio SLP calculated in the slip ratio calculation process is added to the integrated value ΣSLP2, and the process is temporarily terminated.

Here, in the processing of the above steps 420 to 430, after the reference speed KVF is set in step 410, the time until the vehicle speed VF increases by a predetermined speed (1.25 km / h in the present embodiment) is determined by the counter CMYU2. This is a process for counting and integrating the slip ratio SLP during that time.

Also, the value of the counter CMYU2 corresponds to the time required for the vehicle speed VF to increase by 1.25 km / h.
The smaller the value of YU2, the higher the vehicle acceleration, and the value of this counter CMYU2 represents the vehicle acceleration.
Therefore, in the present embodiment, the processing of step 425 corresponds to the vehicle acceleration detecting means M6 described above.

Next, when it is determined in step 420 that the vehicle speed VF is equal to or higher than the reference speed KVF, the process proceeds to step 435, and it is determined whether the value of the counter CMYU2 has exceeded the lower limit value KNO. The lower limit KNO is set to a value corresponding to the shortest time required for the vehicle speed VF to increase by 1.25 km / h. Therefore, in step 435, if the value of the counter CMYU2 is equal to or less than the lower limit value KNO, it is determined that an abnormality has occurred in the value of the counter CMYU2 due to noise or the like, and the process proceeds to step 405 to initialize the counter CMYU2 and the like. After that, the process is temporarily terminated.

Next, at step 435, the value of the counter CMYU2 is set to the lower limit value KN.
If it is determined that the vehicle speed has exceeded O, the process proceeds to the subsequent step 440, where the integrated value ΣSLP2 is divided by the value of the counter CMYU2, so that the average slip ratio ▲ ▼ while the vehicle speed VF increases by 1.25 km / h. Is calculated. And the following step 445
Then, it is determined whether or not the value of the counter CMYU2 is equal to or more than the reference value KAH for high μ determination, and if CMYU2 <KAH, the next step 450
Then, in step 455, the low μ judgment counter CMYUL and the middle μ judgment counter CMYUM are respectively reset, and in step 460, the high μ judgment counter CMYUH is incremented.

In the next step 465, a counter for high μ judgment CMYUH
Is determined to be 2 or more. If CMYUH ≧ 2, the road surface μ is determined to be high μ, the process proceeds to step 470, and the μ data MYULVL is set to high μ. Move to step if CMYUH <2
Move to 410.

On the other hand, if it is determined in step 445 that CMYU2 ≧ KAH, the process proceeds to step 475, and it is determined whether or not the value of the counter CMYU2 is equal to or larger than the low μ determination reference value KAL (> KAH). If it is determined in step 475 that CMYU2 ≧ KAL, the process proceeds to step 480 to determine whether or not the average slip ratio ▲ ▼ is equal to or higher than a predetermined low μ determination reference slip ratio KSLP1. Judge, ▲
If ▼ <KSLP1, go to step 405 described above, ▲
▼ If KSLP1, in the following steps 485 and 490, the medium μ judgment counter CMYUM and the high μ judgment counter C
After resetting MYUH, respectively, at step 495, the low μ judgment counter CMYUL is incremented. In the following step 500, it is determined whether or not the value of the low μ determination counter CMYUL becomes 2 or more. If CMYUL ≧ 2, the road surface μ becomes low μ.
And proceeds to the subsequent step 505, where μ data MYU
After setting LVL to low μ, the process proceeds to step 410 described above. If CMYUL <2, the process directly proceeds to step 410.

Next, in step 475, when it is determined that CMYU2 <KAL, the process proceeds to step 510, where the average slip ratio ▲
It is determined whether or not ▼ is equal to or greater than a predetermined medium μ determination reference slip ratio KSLP2. And ▲
If ▼ <KSLP2, proceed to step 405 described above, and ▲
If ▼ ≧ KSLP2, the following steps 515 and 520
After resetting the low-μ judgment counter CMYUL and the high-μ judgment counter CMYUH, at step 525, the middle μ judgment counter CMYUM is incremented. In step 530, it is determined whether or not the incremented medium μ determination counter CMYUM becomes 2 or more. If CMYUM ≧ 2, the road surface μ is determined to be medium μ, and the next step 535
After setting the medium μ in the μ data MYULVL, the process proceeds to the above-described step 410, and if CMYUM <2, the process directly proceeds to the step 410.

As described above, in the second μ determination processing, the time required for the vehicle body speed VF to increase by 1.25 km / h is obtained as the vehicle body acceleration equivalent value by using the counter CMYU2, and the average slip during this time is determined by the processing of steps 400 to 440. Rate ▲
▼ is calculated, and when it is determined that the value of the counter CMYU2 is smaller than the reference value KAH for high μ determination twice consecutively by the processing of step 445, the road μ is determined to be high μ. ing.

This is because the vehicle cannot be highly accelerated on a low μ road, and can be driven at a high acceleration for the first time on a high μ road. That is, in the second μ determination process, a small value corresponding to a high acceleration that can be realized only on a high μ road is set as the reference value KAH for the high μ determination, and the value of the counter CMYU2 is smaller than the reference value KAH. Whether the vehicle is high μ
By determining whether or not the vehicle is driven at an acceleration that can be realized only on the road, it is determined whether or not the road surface μ is high μ.

In the second μ determination process, step 445, step
In a series of processes of 475 and step 480, the counter C
During low acceleration operation of a vehicle in which the value of MYU2 is equal to or greater than the low μ determination reference value KAL set to a value larger than the high μ determination reference value KAH, the average slip ratio ▲ ▼ is low μ.
It is determined whether or not the reference slip rate KSLP1 for determination is equal to or more than KSLP1.
When it is determined that the road surface is KSLP1, the road surface μ is determined to be low μ. This is because the vehicle acceleration may be reduced when the road μ is low, when the vehicle is slowly accelerated to the extent that the vehicle does not slip, or when the vehicle is gradually accelerated by gravity on the descending road. It is. In other words, in the second μ determination process, the slip ratio ▲ ▼ despite the low vehicle acceleration
Is larger than the reference slip ratio KSLP1 and the drive wheel is slipping, the road μ is determined to be a low μ road, otherwise, the process proceeds to step 405 and the μ determination is restarted from the beginning. By doing so, the road surface μ is accurately identified.

Further, in the second μ determination process, in a series of processes of step 445, step 475, and step 510, KAL ≧
When CMYU2 ≧ KAH, and the vehicle is operated at moderate acceleration, it is determined whether the average slip ratio ▲ ▼ is equal to or more than the reference slip ratio KSLP2 for medium μ determination, and a series of processing If it is determined that ▲ ▼ ≧ KSLP2 successively, it is determined that the road surface μ is medium μ, for the same reason as in the case of the low μ determination described above.

Next, FIG. 8 shows the target opening of the sub-throttle valve 12 at the start of the acceleration slip control, that is, the above-described control start throttle opening θSEN, according to the road surface μ determined by the first or second μ determination processing. It is a flowchart showing a control start throttle opening calculation process to be calculated.

This process is also executed as an interrupt process every predetermined time (for example, 5 msec.) After the start of the internal combustion engine 2 as in the above-described various control processes.
To determine whether the road surface μ is high μ from the latest μ data MYULVL set by the first or second μ determination processing. If the road surface μ is high μ, the process proceeds to the subsequent step 605, and based on the rotational speed NE of the internal combustion engine 2,
The throttle opening θSNEH for high μ is calculated using the map for high μ shown in FIG. 11, and in the next step 610, the calculated throttle opening θSNEH for high μ is set as the control start throttle opening θSEN, In the following step 615, values for high μ set in advance as proportional constants β1 and β2 of the above-mentioned arithmetic expression (2) used when calculating the control amount ΔθS in the acceleration slip control process are set, and the process is performed. Is temporarily terminated.

On the other hand, if it is determined in step 600 that the road surface μ is not high μ, the process proceeds to step 620, and the μ data MYULV
From L, it is determined whether or not the road surface μ is medium μ. If the road surface μ is medium μ, the process proceeds to step 625 to calculate the medium μ throttle opening θSNEM based on the rotation speed NE of the internal combustion engine 2 using the map for medium μ shown in FIG. In the next step 630, the calculated middle μ throttle opening θS
NEM is set as the control start throttle opening θSEN, and in step 635, the values for medium μ are set as the proportional constants β1 and β2 of the above equation (2), and the process is temporarily terminated.

If it is determined in step 620 that the road surface μ is not medium μ, that is, if the road surface μ is low μ,
The process proceeds to 640, and based on the rotation speed NE of the internal combustion engine 2, the first
Using the map for low μ shown in FIG. 1, the throttle opening θSNEL for low μ is calculated, and in the next step 645, the calculated throttle opening θSNEL for low μ is used to start the control.
SEN is set, and in step 650, values for low μ are set as the proportional constants β1 and β2 of the above equation (2), and the process is temporarily terminated.

That is, in the control start throttle opening calculation process, the control start throttle opening θSNE is set using the map shown in FIG. 11 based on the latest road surface μ identified in the first or second μ determination process, Further, the proportional constants β1 and β2 of the arithmetic expression (2) for calculating the control amount are set according to the road surface μ.

Here, the map for calculating the control start throttle opening θSNE is set such that the higher the road surface μ, the larger the control start throttle opening θSNE, as shown in FIG. This is because acceleration slip is more likely to occur as the output torque of the internal combustion engine 2 needs to be suppressed more.

The proportional constants β1 and β2 of the calculation formula (2) for calculating the control amount set in step 615, step 635, or step 650 are set to smaller values as the road surface μ is lower. This is because the lower the road surface μ, the more easily the drive wheels slip, and the speed of the drive wheels fluctuates greatly with a change in the torque of the internal combustion engine 2. That is, by decreasing the proportional constants β1 and β2 as the road surface μ decreases, the amount of change in the output torque of the internal combustion engine 2 is reduced, and the slip ratio SLP is reduced to the target slip ratio S.
They try to converge on the LPO quickly.

Next, FIG. 9 shows that when the road surface μ determined by the first or second μ determination process changes during execution of the acceleration slip control, the control amount of the acceleration slip control according to the road surface μ by a throttle opening change process described later. 9 is a flowchart showing a throttle opening change permission determination process as change prohibiting means for determining whether to change (a target sub-throttle opening in this embodiment).

This process is also executed as an interrupt process at predetermined time intervals (for example, 5 msec.) After the start of the internal combustion engine 2 similarly to the above-described various control processes.
To determine whether or not the control execution flag FS is in the set state and the acceleration slip control is being executed. If the control execution flag FS is in the reset state and the acceleration slip control is not being executed, in steps 705 and 710, the over-close prevention flag FCHGC and the over-open prevention flag FCHGA of the sub-throttle valve 12 are set. At step 715, the counter CNT is reset, and at step 720, a value 0 is set to the integrated value ΣSLP3 of the slip ratio SLP, and the process is terminated once.

On the other hand, if it is determined that the acceleration slip control is being executed while the control execution flag FS is set in step 700, the process proceeds to step 725, where the value of the counter CNT is equal to or more than the preset reference value KCNT. It is determined whether or not. And
If CNT <KCNT, the process proceeds to step 730 and the counter CN
After incrementing T, the process proceeds to step 735, where the slip ratio SLP of the drive wheel calculated in the slip ratio calculation process is added to the integrated value ΣSLP3, and the process is temporarily terminated.

Next, when it is determined in step 725 that CNT ≧ KCNT, that is, after the counter CNT and the integrated value ΣSLP3 are initialized by the processing in steps 715 and 720, the processing in step 730 and step 735 is the reference value. If it has been executed a predetermined number of times (predetermined time) determined by the KCNT, the process proceeds to the subsequent step 740 to divide the integrated value ΣSLP3 by the value of the counter CNT, thereby obtaining a value per predetermined time determined by the counter KCNT. Calculate the average slip ratio ▲ ▼.

In the next step 745, the calculated average slip ratio ▼ is used as a preset first reference slip amount, a reference slip ratio KSLPC for overclose prevention determination.
Judge whether or not it is above, if ▲ ▼ ≧ KSLPC,
Set the overclose prevention flag FCHGC, and
▼ If <KSLPC, reset the overclose prevention flag FCHGC.

In the following step 760, the calculated average slip ratio ▼ is used as a preset second reference slip amount to determine a reference slip ratio KS for preventing over-opening.
Judge whether or not it is equal to or higher than LPA, and if ▲ ▼ ≧ KSLPA, reset the over-open prevention flag FCHGA, and
▼ If <KSLPA, set the over-opening prevention flag FCHGA.

Here, the closing prevention flag FCHGC and the over-opening prevention flag FCHGA are set to a target sub-throttle opening θS0 as a control target in accordance with a change in the road surface μ in a throttle opening changing process described later. Throttle opening θS0
Is a flag for preventing the control characteristic from deteriorating due to setting of unnecessarily small or large.
That is, when the average slip ratio ▲ ▼ is small and the output torque of the internal combustion engine 2 is sufficiently suppressed by the acceleration slip control, when the sub-throttle valve 12 is closed on the assumption that the road surface μ has changed, the rotation of the drive wheels is stopped. If the road surface μ is changed when the output torque of the internal combustion engine 2 is not sufficiently suppressed by the acceleration slip control because the average slip ratio ▲ ▼ is too large and the average slip ratio ▲ ▼ is too large, When the throttle valve 12 is opened, the rotation of the drive wheel excessively increases, and a large acceleration slip may occur on the drive wheel.
The control state of the drive wheel by the acceleration slip control is confirmed by the processing of Step 770, and if the control characteristic deteriorates when the target sub-throttle opening θ S0 is changed to the closing side, the over-close prevention flag FCHGC is reset. Conversely, if the control characteristic deteriorates when the target sub-throttle opening θS0 is changed to the open side, the over-open prevention flag FCHGA is reset, and the sub-throttle valve 12 is opened / closed by a throttle opening change process described later. It prevents it from doing too much.

Next, FIG. 10 determines whether or not the road surface μ has changed based on the identification result of the road surface μ by the first or second μ determination processing. If the road surface μ has changed, the road surface μ is changed to the latest road surface μ. It is a flowchart showing a throttle opening changing process as the road surface change determining means M8 and the control amount changing means M9 for changing the target sub-throttle opening θS0 accordingly.

This process is also executed as an interrupt process at predetermined time intervals (for example, 5 msec.) After the start of the internal combustion engine 2 similarly to the above-described various control processes.
To determine whether or not the control execution flag FS is in the set state and the acceleration slip control is being executed. If the control execution flag FS is in the reset state and the acceleration slip control is not being executed, the process proceeds to step 805 and the μ data MYULVL representing the latest road surface μ determined in the first or second μ determination processing is stored in the next time. It is set as the previous μ data MYULVLO for processing, and the processing is once ended.

Next, if it is determined in step 800 that the control execution flag FS is set and the acceleration slip control is being executed, the process proceeds to step 810, where the current μ data MYULV
It is determined whether or not L matches the previous μ data MYULVLO, that is, whether or not the road surface μ has changed. And MYULVL =
If the road surface μ does not change in MYULVLO, there is no need to change the target sub-throttle opening θS0.
The process proceeds to 15, and it is determined whether the road surface μ is high μ based on the μ data MYULVL.

If it is determined in step 815 that the road surface μ is high μ, that is, if the road surface μ changes from low μ or medium μ to high μ, the process proceeds to step 820 to change the aforementioned throttle opening degree. It is determined whether the over-open prevention flag FCHGA set or reset in the permission determination process is set,
If this flag FCHGA is in the reset state, step 805
Is executed, and the process is temporarily terminated.

On the other hand, if it is determined in step 820 that the over-opening prevention flag FCHGA is set, the process proceeds to step 825, where it is determined whether the current target sub-throttle opening θS0 is smaller than the above-described control start throttle opening θSNE. Judge.
If θSO ≧ θSNE, step 805 is executed and the process is terminated once. If θSO <θSNE, the following step 830 is executed.
The average value of the current target sub-throttle opening θS0 and the control start throttle opening θSNENE (θS0 + θSNE)
/ 2｝ is set as the target sub-throttle opening θS0, and after executing step 805, the process is temporarily terminated.

When it is determined in step 815 that the road surface μ is not high μ, the process proceeds to step 835 to determine whether the road surface μ is low μ based on the μ data MYULVL. And the road surface μ is not low μ, that is, the road surface μ is medium μ
If so, the process proceeds to step 840, where the last μ data MYU
By determining whether LVLO is high μ, the road surface μ
Is changed from high μ to low μ. If it is determined in step 840 that the previous μ data MYULVLO is not high μ, that is, if the road surface μ changes from low μ to medium μ, the process proceeds to step 820 and proceeds to step 820. Execute the following processing.

On the other hand, if it is determined in step 835 that the road surface μ is low μ, or if it is determined in step 840 that the previous road surface μ is a high μ road, the process proceeds to step 845.
It is determined whether the overclose prevention flag FCHGC is set. If the overclose prevention flag FCHGC is in the reset state, the process directly proceeds to step 805; otherwise, the process proceeds to step 850 to determine whether the current target sub-throttle opening θS0 exceeds the control start throttle opening θSNE. If θS0 ≦ θSNE, the process proceeds to step 805, and if θS0> θSNE, the process proceeds to step 830.

Thus, in the throttle opening change processing, the road surface μ
If it changes to the high μ side where slip does not easily occur, make sure that the over-open prevention flag FCHGA is set and that the control start throttle opening θSNE is larger than the current target sub-throttle opening θS0. , Step 830
The target sub-throttle opening θ S0 is changed to the opening direction by executing the processing of FIG.
HGC is set and control start throttle opening θS
After confirming that NE is smaller than the current target sub-throttle opening θS0, the processing of step 830 is executed to change the target sub-throttle opening θS0 to the closing direction.

As described in detail above, in the acceleration slip control device of the present embodiment, in the second μ determination processing, the road surface μ is determined in advance based on the vehicle body acceleration (actually, a count value representing the vehicle body acceleration) and the average slip ratio ▲ ▼. The target sub-throttle opening .theta.S0 when the road .mu. Changes based on the discrimination result in the throttle opening change process is determined by identifying which of the set low .mu., Medium .mu., And high .mu. Is changed to a value according to.

Therefore, for example, as shown in FIG. 12 (a), when the road surface μ changes from the medium μ to the low μ during the execution of the acceleration slip control, the change in the road surface μ is promptly detected at the time t1. The target sub-throttle opening θ S0 can be changed to a value corresponding to the road surface μ, and the output torque of the internal combustion engine 2 is further suppressed by driving the sub-throttle valve 12 in the closing direction;
It is possible to quickly control the slip ratio of the drive wheels to the target slip ratio.

In the present embodiment, as a process for identifying the road surface μ, a first μ determination process for identifying the road surface based on the average slip ratio ▲ ▼ immediately after the start of the acceleration slip is also executed separately from the second μ determination process. Has been. For this reason, it is possible to identify the road surface μ in the driving region where the road surface μ cannot be determined in the second μ determination process, that is, in the region immediately after the occurrence of the acceleration slip where the vehicle is not actually accelerated.

Therefore, for example, as shown in FIG. 12 (b), when the road surface μ changes from medium μ to low μ immediately after the start of the acceleration slip control at time t2, the change is determined by the road surface μ in the first μ determination processing.
, The target sub-throttle opening θ S0 can be changed to a value corresponding to the road surface μ, and the sub-throttle valve 12 is driven in the closing direction to output the internal It is possible to further suppress the torque and quickly control the slip ratio of the drive wheels to the target slip ratio.

FIG. 12 (b) also shows a control operation when the road surface μ changes from low μ to medium μ during the execution of the acceleration slip control at the time point t3. As is clear from the drawing, the road surface μ becomes high μ. If it changes to the side, the target sub-throttle opening θS0 is changed to the throttle opening direction according to the road surface μ, and the slip ratio of the drive wheels can be quickly controlled to the target slip ratio.

Further, in the present embodiment, when the target sub-throttle opening θS0 is changed in accordance with the change of the road surface μ in the throttle opening change processing, the over-close prevention flag set / reset in the throttle opening change permission determination processing. After confirming that the FCHGC or the over-opening prevention flag FCHGA has not been reset, the target sub-throttle opening θS0 is changed to the closing or opening direction.

Therefore, for example, as shown in FIG. 12 (c), even when the road surface μ changes from medium μ to low μ during the execution of the acceleration slip control, the slip ratio SLP of the drive wheel is changed to the target slip ratio at time t4. When the vehicle is well controlled in the vicinity of SLPO, the target throttle opening θS0 is not changed, and as a result, the target throttle opening θS0 is changed too much with the change of the road surface μ, and the control accuracy of the acceleration slip control is changed. Can be prevented from being reduced.

Further, in this embodiment, the proportional constants β1 and β2 of the arithmetic expression (2) used for calculating the target sub-throttle opening θS0 are changed according to the identification result of the road surface μ by the first or second μ determination processing. The sub throttle valve 12
, The output torque of the internal combustion engine 2 can be more optimally controlled in accordance with the road surface μ, whereby the control accuracy can be improved.

Here, in the above-described embodiment, the slip ratio is calculated by using the above-described equation (1) as the slip amount representing the magnitude of the slip of the drive wheel. The deviation from VF may be calculated as the slip amount.

Further, in the above embodiment, the acceleration slip control is executed by the output torque control of the internal combustion engine 2 using the F / C control of the internal combustion engine 2 and the sub-throttle opening degree control. Alternatively, the output slip control may be performed by controlling the output torque of the internal combustion engine 2 by retarding the ignition timing, or the acceleration slip control may be performed by braking control using a brake device. Is also good.

Further, in the above embodiment, the F / C control for suppressing the output torque of the internal combustion engine 2 immediately after the occurrence of the acceleration slip is executed until the rotational acceleration ΔNE of the internal combustion engine 2 becomes equal to or less than a predetermined value. However, after the start of the control, the control may be executed until the drive acceleration of the drive wheels becomes equal to or less than a predetermined value, or may be executed until the rotational speed NE of the internal combustion engine becomes equal to or less than a predetermined value.

[Effects of the Invention] As described above in detail, in the acceleration slip control device of the present invention, a plurality of road surface conditions in which the traveling road surface of the vehicle is classified according to the road surface friction coefficient based on the slip amount of the driving wheels and the vehicle acceleration. If the identification result changes during the execution of the acceleration slip control, the vehicle running road surface has a low road surface friction coefficient from a road surface having a high road surface friction coefficient according to the change in the road surface state. When the road surface changes, the control amount for the acceleration slip control is changed in a direction to further suppress the rotational torque of the drive wheels, and conversely, when the vehicle running road surface changes to a road surface having a high road surface friction coefficient. In this case, the control amount for the acceleration slip control is changed in a direction to reduce the suppression of the rotational torque of the drive wheels.

Then, the slip amount of the drive wheel is set to the first preset value.
When the slip amount is smaller than the reference slip amount, change of the control amount in the direction of suppressing the driving wheel and the rotational torque according to the change in the road surface condition is prohibited, and the slip amount of the driving wheel is set to the second reference slip amount set in advance. When it is larger, the change of the control amount in the direction of reducing the suppression of the rotational torque of the drive wheels according to the change of the road surface condition is prohibited.

For this reason, according to the present invention, even if the vehicle traveling road changes from the high μ road to the low μ road or the reverse direction during the acceleration slip control, the rotational torque of the drive wheels is adjusted according to the road surface state. It can be controlled quickly to the optimum value, and when the vehicle running road changes from high μ road to low μ road, the rotational torque of the drive wheels cannot be sufficiently suppressed and a large acceleration slip recurs, or conversely When the vehicle traveling road changes from a low μ road to a high μ road, the rotational torque of the drive wheels is excessively suppressed,
It is possible to prevent the vehicle from exhibiting sufficient acceleration performance, and at the time of vehicle acceleration, it is possible to cause the vehicle to run at the maximum acceleration while suppressing acceleration slip.

Moreover, according to the present invention, when the slip amount of the drive wheel is smaller than the first reference slip amount, it is prohibited to change the control amount in a direction to suppress the rotational torque of the drive wheel according to the change of the road surface μ. Therefore, it is possible to prevent the rotation of the driving force from being excessively suppressed, thereby preventing good acceleration from being obtained. In addition, when the slip amount of the driving wheel is larger than the second reference slip amount, the driving according to the change in the road surface μ is performed. By prohibiting a change in the control amount in a direction that reduces the suppression of the rotation torque of the wheels, it is possible to prevent the rotation of the drive wheels from excessively increasing and causing a large acceleration slip.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, FIG. 2 is a schematic configuration diagram showing the overall configuration of the acceleration slip control device of the embodiment, FIG. 3 is a block diagram showing the configuration of an acceleration slip control circuit, FIG. FIG. 5 is a flowchart showing a slip ratio calculation process executed by the acceleration slip control circuit. FIG. 5 is a flowchart showing the acceleration slip control process.
FIG. 6 is a flowchart showing the first μ determination process, FIG. 7 is a flowchart showing the second μ determination process, FIG. 8 is a flowchart showing the control start throttle opening calculation process, and FIG. FIG. 10 is a flowchart showing a change permission determination process, FIG. 10 is a flowchart showing a throttle opening degree change process, and FIG.
FIG. 12 is a diagram showing a map used for calculating the control start throttle opening in accordance with the road surface μ, and FIG. 12 is a time chart for explaining the operation of the acceleration slip control of the embodiment. M1,22RL, 22RR ... Drive wheel M2 ... Drive wheel speed detection means M3 ... Slip amount calculation means M4 ... Acceleration slip detection means M5 ... Acceleration slip control means M6 ... Vehicle acceleration detection means M7 ... Road surface condition Identification means M8: Road surface change determination means M9: Control amount change means, M10: Change prohibition means 2: Internal combustion engine, 12: Subthrottle valve 20: Acceleration slip control circuit 26: Internal combustion engine control circuit

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B60K 41/00-41/28 B60T ⁷ /12-7/22 B60T 8/32-8/96 F02D 29/00-29 / 06 F02D 41/00-41/40

Claims (1)

(57) [Claims] 1. A driving wheel speed detecting means for detecting a rotating speed of a driving wheel, and a slip representing a magnitude of a slip generated on the driving wheel when the vehicle is accelerating, using the detected rotating speed of the driving wheel as one parameter. A slip amount calculating means for calculating the amount; an acceleration slip detecting means for detecting an acceleration slip of the driving wheel based on the calculated slip amount; An acceleration slip control means for controlling the rotational torque of the drive wheels such that the slip amount is equal to a preset target slip amount. Means, based on the detected vehicle acceleration and the slip amount of the drive wheel, the vehicle traveling road surface is classified in advance according to a road surface friction coefficient. Road surface state identification means for identifying which of the number of road surface states, and a road surface on which the vehicle travels, from a road surface with a high road surface friction coefficient to a road surface with a low road surface friction coefficient, Or, a road surface change determining means for determining whether or not the vehicle has changed in the opposite direction. If the road surface change determining means determines that the vehicle running road surface has changed to a road surface having a low road surface friction coefficient, the acceleration slip is performed. The control amount by the control means is changed in a direction to further suppress the rotational torque of the drive wheels, and when it is determined that the vehicle traveling road surface has changed to a road surface having a high road surface friction coefficient, the control amount by the acceleration slip control means is changed. Control amount changing means for changing the suppression of the rotational torque of the drive wheel in a direction to reduce the torque, and when the slip amount of the drive wheel is smaller than a first reference slip amount set in advance, The control amount changing means prohibits the change of the control amount in a direction to suppress the rotational torque of the drive wheel, and when the slip amount of the drive wheel is larger than a second reference slip amount set in advance, the control amount An acceleration slip control device for a vehicle, comprising: a change prohibition unit that prohibits a change in the control amount in a direction that reduces the suppression of the rotational torque of the drive wheels by the change unit.