JP2948679B2 - Vehicle slip control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle slip control device, and more particularly to a vehicle having a driving force distribution means such as a differential device for distributing an engine output to a power transmission path from an engine to left and right driving wheels. The present invention relates to a slip control device that controls a driving force according to a slip state of a wheel.

[0002]

2. Description of the Related Art In recent years, in vehicles, traction control for suppressing a driving force when a driving wheel slips is carried out in order to prevent a driving wheel from slipping due to an excessive driving torque and a starting performance or an acceleration performance from being reduced. There's something we did. This traction control is started, for example, based on a signal from a wheel speed sensor that detects the rotation speed of a wheel, when the rotation speed difference between a driven wheel and a driven wheel becomes equal to or greater than a predetermined value. By controlling the engine output or the braking force in a feedback manner so as to converge to the target value, the driving force acting on the driving wheels is reduced.

On a slippery road such as a snowy road, when excessive torque is transmitted to the drive wheels at the time of starting or accelerating, the rotational speed of the drive wheels is increased due to the difference in the coefficient of friction between the drive wheels and the road surface on which the wheels contact the ground. A difference may occur, causing the vehicle to enter a slip state called skidding. In particular, this phenomenon is remarkably observed in a vehicle equipped with a driving force distribution means such as a differential device in a power transmission path from an engine to left and right driving wheels.

In order to solve such a problem, for example, as disclosed in Japanese Patent Application Laid-Open No. Sho 60-128028, power from a power plant is distributed to left and right driving wheels via differential gears. In the vehicle,
In some cases, the rotational speeds of the left and right drive wheels are individually detected, and the drive torque output from the power plant is reduced while the rotational speeds of these drive wheels are different. According to this, when there is a rotational speed difference between the left and right driving wheels, the engine output and the like are reduced, so that an excessive driving force is not transmitted to the left and right driving wheels, and the above-described disadvantage is avoided. Will be.

[0005]

By the way, in a cold region or the like, there are many chances of traveling on a so-called split road surface in which the left and right drive wheels have different friction states on the road surface. In this case, if the drive torque is reduced uniformly when the rotational speeds of the left and right drive wheels are different as in the prior art described in the above-mentioned publication, for example, a road surface on which one of the wheels touches the ground may hinder normal traveling. Even if there is a slight degree of grip force, if the grip force on the road surface where the other wheel touches the ground is somewhat insufficient, the drive torque will be reduced due to the difference in rotational speed between both drive wheels, Even if the driver has a desire to run, sufficient starting or accelerating properties cannot be obtained contrary to the will.

Therefore, in normal times, normal traction control (hereinafter referred to as normal control) for simply suppressing the driving force when the driving wheels are in a spin state is performed, and on a split road surface, emphasis is placed on startability or acceleration. Attention has been paid to the idea of switching to split control for increasing the engine output, but in that case, the accuracy of the split road surface determination becomes a problem. That is, for example, when driving on a low μ road such as an ice burn, the left and right driving wheels may alternately be in a spin state. There is a possibility of making a decision. Also,
In some cases, the spin state of the slipping drive wheel may temporarily stop when traveling on a split road surface, but simply stopping the split control in this case may result in poor responsiveness when re-spin occurs. Become.

The present invention relates to a vehicle slip control device provided with a driving force distribution means for distributing engine output to left and right driving wheels on a power transmission path from an engine to left and right driving wheels. An object is to enable slip control.

[0008]

That is, a vehicle slip control device according to the invention of claim 1 of the present application (hereinafter referred to as a first invention), as shown in FIG. In a vehicle provided with driving force distribution means for distributing the engine output to the left and right driving wheels in the power transmission path and provided with driving force control means A for controlling the driving force according to the slip state of the driving wheels, First and second spin detecting means B and C for periodically detecting the spin states of the driving wheels, and the spin states of the left and right driving wheels detected by the first and second spin detecting means B and C, respectively. A spin pattern determining means D for sequentially determining a spin pattern of a driving wheel based on the
And a split determination unit E for performing a split determination on a road surface on which each of the driving wheels comes into contact with the ground according to a preset split determination rule from the previous spin pattern and the current spin pattern determined in (1). .

The invention of claim 2 of the present application (hereinafter referred to as “second
The vehicle slip control device according to the present invention includes a driving force distribution unit that distributes engine output to the left and right driving wheels in a power transmission path from the engine to the left and right driving wheels,
In a vehicle provided with a driving force control means A for controlling a driving force in accordance with a slip state of a driving wheel, first and second detecting means for periodically detecting the spin states of the left and right driving wheels, respectively, as in the first embodiment. Two-spin detecting means B and C, and a spin-pattern determining means D for sequentially determining the spin patterns of the driving wheels based on the spin states of the left and right driving wheels detected by the first and second spin detecting means B and C, respectively.
A split determination unit E that performs a split determination on the road surface on which each of the drive wheels contacts the ground according to a preset split determination rule from the previous spin pattern and the current spin pattern determined by the spin pattern determination unit D; Is provided. Then, when one of the left and right drive wheels is in the spin state last time,
This time, it is set so that split determination is performed even when both drive wheels are in the non-spin state.

Further, the vehicle slip control device according to the invention of claim 3 of the present application (hereinafter referred to as a third invention) distributes the engine output to the left and right drive wheels on a power transmission path from the engine to the left and right drive wheels. In a vehicle provided with driving force distributing means for controlling the driving force in accordance with the slip state of the driving wheels, the vehicle is provided with a driving force control means A for controlling the driving force according to the slip state of the driving wheels. First and second spin detecting means B and C which are periodically detected, and spin patterns of the driving wheels based on the spin states of the left and right driving wheels which are respectively detected by the first and second spin detecting means B and C. Pattern determining means D for sequentially determining
A split determination unit E that performs a split determination on the road surface on which each of the drive wheels contacts the ground according to a preset split determination rule from the previous spin pattern and the current spin pattern determined by the spin pattern determination unit D; Is provided. Then, when the spin state of the left and right drive wheels detected by the first and second detection means B and C indicates the non-spin state of both drive wheels, one of the left and right drive wheels last time was in the spin state. In some cases, a delay means F for delaying the end time of the split determination by the split determination means E is provided.

The vehicle slip control device according to the invention of claim 4 of the present application (hereinafter referred to as a fourth invention) distributes the engine output to the left and right drive wheels on a power transmission path from the engine to the left and right drive wheels. In a vehicle provided with driving force distributing means for controlling the driving force in accordance with the slip state of the driving wheels, the vehicle is provided with a driving force control means A for controlling the driving force according to the slip state of the driving wheels. First and second spin detecting means B and C which are periodically detected, and spin patterns of the driving wheels based on the spin states of the left and right driving wheels which are respectively detected by the first and second spin detecting means B and C. Pattern determining means D for sequentially determining
A split determination unit E that performs a split determination on the road surface on which each of the drive wheels contacts the ground according to a preset split determination rule from the previous spin pattern and the current spin pattern determined by the spin pattern determination unit D; Is provided. In the case where the spin state of the left and right drive wheels detected by the first and second detection means B and C indicates the non-spin state of both drive wheels, when one of the left and right drive wheels was in the spin state last time, A delay means F for delaying the end time of the split determination by the split determination means E, and a delay time setting means G for setting a delay time for the delay means F in accordance with the split determination time in the determination means E. .

On the other hand, the invention of claim 5 of the present application (hereinafter referred to as the fifth invention)
The vehicle slip control device according to the present invention includes a driving force distribution unit that distributes engine output to the left and right driving wheels in a power transmission path from the engine to the left and right driving wheels,
In a vehicle provided with a driving force control means A for controlling a driving force in accordance with a slip state of a driving wheel, first and second detecting means for periodically detecting the spin states of the left and right driving wheels, respectively, as in the first embodiment. Two-spin detecting means B and C, and a spin-pattern determining means D for sequentially determining the spin patterns of the driving wheels based on the spin states of the left and right driving wheels detected by the first and second spin detecting means B and C, respectively.
A split determination unit E that performs a split determination on the road surface on which each of the driving wheels contacts the ground according to a preset split determination rule from the previous spin pattern and the current spin pattern determined by the spin pattern determination unit D; Is provided. Then, when one of the left and right drive wheels is in the spin state last time and the other drive wheel is in the spin state next time, the split determination should not be performed even if the one drive wheel is in the non-spin state this time. Set.

[0013]

According to the first to fifth aspects of the present invention, the spin patterns are sequentially determined according to the spin states of the left and right driving wheels periodically detected by the first and second spin detecting means B and C, respectively. At the same time, since the split determination is performed from the previous spin pattern and the current spin pattern in accordance with a preset split determination rule, it is possible to control the driving force appropriately reflecting various road surface conditions.

In particular, according to the second invention, the split determination rule is set so that when one of the left and right drive wheels is in the spin state last time, the split determination is performed even if both drive wheels are in the non-spin state this time. Therefore, even when the spin state temporarily stops, the state is not determined to be the non-split state, whereby accurate split determination is performed.

According to the third aspect of the present invention, when one of the left and right driving wheels is in the spin state last time when the left and right driving wheels indicate the non-spin state, the end time of the split determination is delayed. Therefore, the responsiveness of the split control at the next spin is improved.

According to the fourth aspect, the delay time of the end time of the split determination is set according to the time of the split determination, so that the responsiveness of the split control at the next spin is further improved. become.

According to the fifth aspect of the present invention, when one of the left and right drive wheels is in the spin state last time and the other drive wheel is in the spin state next time, the one drive wheel is now in the non-rotation state. Since it is set not to perform the split determination even in the spin state, there is no erroneous determination that the vehicle is on the split road surface even though the vehicle is not on the split road surface, whereby accurate split determination is performed.

[0018]

Embodiments of the present invention will be described below.

As shown in FIG. 2, the vehicle according to this embodiment has left and right front wheels 1, 2 as driven wheels, left and right rear wheels 3, 4 as driving wheels, and the output torque of the engine 5 is reduced. The transmission is transmitted from the transmission 6 to the left and right rear wheels 3 and 4 via the propeller shaft 7, the differential device 8 and the left and right drive shafts 9 and 10.

Each of the wheels 1 to 4 has a disk 11a to 14a integrally rotating with the wheels 1 to 4,
Upon receiving the braking pressure, these disks 11a to 11a
Brake devices 11 to 14 including calipers 11b to 14b for braking the rotation of a are provided, respectively, and a brake control system 15 for performing a brake operation of these brake devices 11 to 14 is provided.

The brake control system 15 includes a booster 17 for increasing the stepping force on the brake pedal 16 by the driver, and a master cylinder 18 for generating a braking pressure corresponding to the stepping force increased by the booster 17. And Front-wheel braking pressure supply lines 19 and 20 led from the master cylinder 18 are connected to calipers 11b and 12b of brake devices 11 and 12 in left and right front wheels 1 and 2, respectively. The braking pressure corresponding to the depression force of the brake pedal 16 generated in the master cylinder 18 is directly applied to the brake devices 11 and 12 of the left and right front wheels 1 and 2 via the respective front wheel braking pressure supply lines 19 and 20. The front wheels 1 and 2 are respectively braked by the braking force supplied according to these braking pressures.

On the other hand, the booster 17 has an operating pressure supply line 22 for supplying the operating pressure from the pump 21 and a return line 23 for returning excess brake oil generated by the booster 17 to the reservoir tank. The first braking pressure supply line 2 connected and guided from the booster 17
4 and a second brake pressure supply line 25 branched from the pump discharge side of the working pressure supply line 22 are provided with electromagnetic first and second on-off valves 26 and 27, respectively.
A check valve 28 for preventing backflow is provided in the first braking pressure supply line 24 in parallel with the first on-off valve 26.
The first and second brake pressure supply lines 24 and 25 are joined at a point X, and the calipers 13b and 14 of the brake devices 13 and 14 on the right and left rear wheels 3 and 4 are joined from the junction X.
b, the brake pressure supply lines 29, 30 for the rear wheels are guided, and on these brake pressure supply lines 29, 30
Electromagnetic on-off valves 31, 32 and relief valves 33, 34 are provided, respectively.

On the other hand, a main throttle valve 37 connected to an accelerator pedal 36 operated by a driver and a sub-throttle valve 39 connected to a throttle opening adjustment actuator 38 are provided in an intake passage 35 of the engine 5. And the throttle valves 37, 39
By adjusting the opening of the engine 5, the intake air amount of the engine 5 is variably controlled and the engine output is adjusted.

An electronic control unit (hereinafter referred to as ECU) 40 for performing traction control.
The ECU 40 includes signals from wheel speed sensors 41 to 44 for detecting rotation speeds of the wheels 1 to 4 and an engine speed sensor 4 for detecting engine speed.
5 and a first pressure sensor installed downstream of the on-off valve 31 in the rear wheel brake pressure supply line 29 communicating with the brake device 13 of the left rear wheel 3 for detecting the brake pressure supplied to the brake device 13. A pressure sensor 46 and a second pressure that is installed downstream of the on-off valve 32 in the rear wheel brake pressure supply line 30 that communicates with the brake device 14 for the right rear wheel 4 and detects the brake pressure supplied to the brake device 14 A sensor 47, a signal from an accelerator position sensor 48 for detecting the amount of depression of the accelerator pedal 36, and a signal from a steering angle sensor 49 for detecting a steering angle are input, and based on these signals, the brake control system On-off valve 26 at 15
27. Operation of 31 and 32 and relief valves 33 and 34;
The operation of the throttle opening adjustment actuator 38 for adjusting the opening of the sub-throttle valve 29 is controlled. That is, the control signal from the ECU 40 opens the first on-off valve 24 on the first brake pressure supply line 24, closes the second on-off valve 27 on the second brake pressure supply line 25, and Brake pressure supply line 29,3
When the open / close valves 31 and 32 on the zero are open, the braking pressure corresponding to the depressing force of the brake pedal 16 generated by the booster 17 is applied to the left and right via the first braking pressure supply line 24. The braking force is supplied to the brake devices 13 and 14 of the rear wheels 3 and 4, and the rear wheels 3 and 4 are respectively braked by a braking force corresponding to these braking pressures.

On the other hand, when performing traction control by brake control, the ECU 40 closes the first opening / closing valve 26 and opens the second opening / closing valve 27. Therefore, the operating pressure generated by the pump 21 does not pass through the booster 17 and is used as the braking pressure supply line 2 for the rear wheels as the braking pressure.
9 and 30.

When, for example, the spin state of the left rear wheel 3 is detected from the signals from the wheel speed sensors 41 to 44, that is, the average front wheel speed V obtained by averaging the rotational speeds of the front wheels 1 and 2 as driven wheels. When it is detected that the rotation speed of the rear wheel 3 that is the driving wheel is high with reference to _F , the on-off valve 31 and the relief valve 33 on one of the rear wheel braking pressure supply lines 29 are opened and closed by duty control. A braking force is applied to the rear wheel 3 with a braking pressure according to a slip state. When the spin state of the right rear wheel 4 is detected, the on-off valve 32 and the relief valve 34 on the other rear wheel braking pressure supply line 30 are opened and closed by duty control, and the braking corresponding to the slip state is performed. The braking force is applied to the rear wheel 4 by the pressure. That is, in this embodiment, the braking forces applied to the left and right rear wheels 3, 4 are controlled independently.

Particularly, in this embodiment, the ECU
The reference numeral 40 designates split determination of the road surface condition based on the signals input from the wheel speed sensors 41 to 44. That is, the ECU 40 sequentially determines the spin patterns of the left and right rear wheels 3 and 4 that are the driving wheels based on the signals input from the wheel speed sensors 41 to 44 for each control cycle, and stores the spin patterns in the memory 50 The split pattern is compared with the current spin pattern and a split determination map stored in advance in ROM. Then, while set to 1 split control flag F _S when other predetermined execution condition is satisfied, the split control flag F _S so as to reset to 0 when a predetermined releasing condition is satisfied I have.

A timer 51 for managing the split control is connected to the ECU 40.

Next, the traction control in this embodiment will be described. This traction control is performed as follows in accordance with the flowchart of FIG.

That is, after reading various data in step S1, the ECU 40 executes friction coefficient estimation processing in step S2, and executes split determination processing in step S3. The split control flag F _S is determined whether it is set to 1 at step S4, to execute the normal control in step S5 must be set to 1. On the other hand, if the flag F _S has been set to 1, the flow shifts to step S6 to execute a predetermined split control.

Here, the outline of the friction coefficient estimating process will be described. For example, the following process is performed for the left rear wheel 3. That is, the ECU 40 determines the wheel speed sensor 41,
The average front wheel speed signal from 42 is determined from the rotational speed of the left and right front wheels 1 and 2 shown V _F is the predetermined lower limit value V ₀ (e.g. 5km
/ H) determined is smaller than or not, when the average front wheel speed V _F exceeds the lower limit value V ₀ is the road surface friction coefficient by the front wheel acceleration A _F obtained from the average front wheel speed V _F and the average front wheel speed V _F to estimate the μ _L.

Here, the road surface friction coefficient μ As a very low μ road
Number divided into 5 steps from 1 shown to 5 showing high μ road
One of the values is to be selected.

On the other hand, when the ECU 40 determines that the average front wheel speed V _F is smaller than the lower limit value V _0, the rear wheel acceleration A _RL obtained from the left rear wheel speed V _RL indicated by the signal from the sensor 43 is equal to or larger than a predetermined value. Is determined to be greater than a reference value A ₀ (for example, 2G), and when YES is determined, the starting μ
After having set the estimation flag F _MS 1, so as to estimate the road surface friction coefficient mu _L for the left rear wheel 3 in accordance with the engine speed N indicated by the signal from the engine speed sensor 45.

Further, when the rear wheel acceleration A _RL is determined to be smaller than the reference value A ₀ is selected fixed value as the road surface friction coefficient mu _L (e.g. 3).

Incidentally, the road surface friction coefficient μ _R is similarly estimated for the right rear wheel 4.

In the normal control, the left and right rear wheels 3,
For example, for the left rear wheel 3, it is performed as follows. That is,
ECU40 is a road surface friction coefficient mu _L reads the engine control target reference value and the brake control target reference value from a map that is set as a parameter in advance, is corrected in accordance with the average front wheel speed V _F representative of vehicle speed these values Thus, a final engine control target value S _E and a brake control target value S _B are obtained.

[0037] Then, from the left rear wheel speed V _RL showing signals from the wheel speed sensor 43, the first slip for the left rear wheel 3 by subtracting the average front wheel speed V _F indicated by the signal from the wheel speed sensors 41 and 42 and calculating a value S _1, the first slip value S ₁ is, starts the engine control at the time of exceeding the engine control target value S _E, as shown in FIG. 4 (t _1), the target value S _E The sub-throttle valve 39 is feedback-controlled via the throttle opening adjustment actuator 38 so as to be obtained. Accordingly, the output torque of the engine 5 is to be controlled to converge to the engine control target value S _E.

[0038] Once this also continues to rise the left rear wheel speed V _RL without eliminating slip state by the engine control, the first slip value S ₁ is greater than the brake control target value S _B (t _2), A braking pressure is supplied to the brake device 13 in the rear wheel 3, and control using both engine control and brake control is performed. The braking pressure is equal to the first slip value S.
₁ is feedback controlled so that the brake control target value S _B.

[0039] Then, the first slip value S ₁ is at the time when lowered to the brake control target value S _B (t _3), the brake pressure is reduced brake control is stopped. The engine control is performed until a predetermined termination condition is satisfied.

It should be noted that normal control is similarly performed for the right rear wheel 4. That, ECU 40 is the wheel speed sensor from the right rear wheel speed V _RR indicating signal from 44, the average second relative wheel speed right rear wheel 4 by subtracting a V _F
Calculates the slip value S _2. Then, the first slip value S ₂ is started engine control at the time of exceeding the above and set in the same manner by an engine control target value S _E, a throttle opening adjustment as the target value S _E can be obtained The sub-throttle valve 39 is feedback-controlled via the actuator 38. This also continues to rise the right rear wheel speed V _RR without eliminating slip state by the engine control, engine control and the brake control at the second slip value S ₂ has exceeded in the same manner as above brake control target value S _B The control using both of them is performed. The second slip value S ₂ is at the time when lowered to the brake control target value S _B, so that the braking pressure is reduced brake control is stopped.

On the other hand, in the split control, for example, the engine control target value S _E is set higher than usual. That is, for example, the right rear wheel 4 is that there the easy availability slip than the left rear wheel 3, the second slip value S ₂ for the right rear wheel 4 is braked for the rear wheels at the time of exceeding the braking control target value S _B A braking pressure is supplied to the brake device 14 via the pressure supply line 30, whereby a braking force is applied to the right rear wheel 4. In this case, when the first slip values S ₁ for relatively slip hardly left rear wheel 3 with respect to the right rear wheel 4 does not reach the brake control target value S _B is
Since no braking pressure is supplied to the brake device 13, the left rear wheel 3
The braking force does not act on. Therefore, the distribution ratio of the driving force to the left rear wheel 3 is increased, and the function of the differential device 8 is apparently restricted. As a result, the engine output, which is increased by the amount that the engine control target value S _E is set higher than usual, is transmitted to the left rear wheel 3 preferentially. Acceleration will be improved.

Next, the split determination process, which is a feature of the present invention, will be described in detail with reference to the flowchart of FIG.

[0043] That is, ECU 40 in terms of reading the various data in step T1, determining the spin pattern P _SP for the left and right rear wheels 3 and 4 at step T2. That, ECU 40 first slip value S ₁ is obtained from the left rear wheel speed V _RL and the average front wheel speed V _F, and sets the first spin flag F ₁ to 1 for example, when it exceeds the engine control target value S _E , and the second slip value S ₂ is obtained from the right rear wheel speed V _RL and the average front wheel speed V _F, also sets the second spin flag F ₂ to 1 when exceeding the engine control target value S _E. Then, these first and second spin flags F ₁ , F ₂
By collating the spin pattern map set in advance spin flag as a parameter, sequentially determines the spin pattern P _SP time. Here, as shown in FIG. 6, when the first and second spin flags F ₁ and F ₂ are both 0, the value of the current spin pattern P _SP is 0 and the first spin flag F ₁ is, as shown in FIG. Is 1 and 2
This When spin flag F ₂ is 1 spin pattern P
_When the value of _SP is 1, the first spin flag F ₁ is 0, and the second spin flag F ₂ is 0, the value of the current spin pattern P _SP is 2, and both the first and second spin flags F ₁ and F ₂ are changed. When the value is 1, the value of the current spin pattern P _SP is set to 3.

Next, the ECU 40 stores the current spin pattern P _SP determined in step T3 and the previous spin pattern P ^′ _SP stored in the memory 50 in advance in the two patterns P _SP , P ^′ _{SP as} shown in FIG. Is compared with a split determination map set as a parameter to perform split determination (step T3).

[0045] Here, the split determination map, as shown in FIG. 7, when the current spin pattern P _SP indicates the left and right rear wheels 3 and 4 non-spin state is basically the value of the split determination flag F _SP Is set to 0 indicating a non-split state, but when one of the left and right rear wheels 3 and 4 indicates a spin state last time, the flag F
The value of _SP is set to 2 indicating the split continuation state. This is to improve responsiveness when re-spin occurs. Further, when one of the left and right rear wheels 3 and 4 indicates the spin state in the current spin pattern P _SP, the value of the split determination flag F _SP is basically set to 1 indicating the split state. 0 but the last time the other rear wheels 3 and 4 show a spin state, indicating a non-split state as the value of the flag F _SP
It is set to be. This is to prevent an erroneous determination of the split state when the left and right driving wheels alternately spin during running on a low μ road such as an ice burn. And this time spin pattern P
_{When the SP} indicates that both the left and right rear wheels 3 and 4 are in the spin state, the value of the split determination flag F _SP is set to 0 indicating the non-split state.

[0046] Then, ECU 40 proceeds to step T4 in the flowchart of FIG. 5, the split determination flag F _SP
Is determined to be 2 or not, and if NO is determined, step T
5 to change the current spin pattern P _SP to the previous spin pattern P ^'
Is replaced with in the _SP, the holding of the previous spin pattern P _^'SP branches to step T6 when it is determined that YES.

[0047] Then, ECU 40 along with the value of the split determination flag F _SP to determine 0 or not in step T7, after resetting the count value T _M of the timer 51 goes to step T8 it is determined YES, and step At T9, the value of the split control flag F _S is set to 0 at which the split control is not performed.

Meanwhile, ECU 40 when it is determined that the value of the split determination flag F _SP is not 0 in step T8, the value of the split determination flag F _SP is determined whether 2 or not in step T10, it is determined that the NO When the process proceeds to step T11, the count value T
_M is determined whether it exceeds a predetermined upper limit value T ₀ (for example, 10 seconds), after adding the count value T _M in step T12 when it is determined NO, and the count value in step T13 T _M Is determined to be 0 or not, and when determined to be NO, the process proceeds to step T14 to determine whether or not the count value T _M exceeds a predetermined lower limit value T ₁ (for example, 0.5 seconds). In addition, when the determination is YES, step T
The program then proceeds to 15 where the differential pressure δp of the brake oil pressure indicated by the signals from the first and second pressure sensors 46 and 47 is equal to a predetermined reference value p.
It is determined whether or not the value exceeds _{0. If the} determination is YES, the process proceeds to step T16, where the split control flag F _{S is determined.}
Is set to 1 for executing the split control.

[0049] Furthermore, ECU 40 when it is determined that the value of the split determination flag F _SP in step T10 is 2, the return branches to step T17 to step T13 after subtracting the count value T _M of the timer 51 I do. If the count value T _M is 0 at that time, the process goes to step T9 to set the value of the split control flag F _S to 0. As a result, the split control is released, and the control shifts to the normal control.

If the determination in step T14 is NO, the ECU 40 proceeds to step T18 to determine whether or not the start-time μ estimation flag _FMS is set to 1. That is, it is determined whether or not the road surface friction coefficient has been estimated at the time of starting. Then, the flag F
When _{the MS} is set to 1, the road surface friction coefficient mu _L of the right and left advances to step T19, the deviation of μ _R δμ (= | μ
_L− μ _R |) exceeds a predetermined reference value μ ₀ , and when YES is determined, the process returns to step T15 to be detected by the first and second pressure sensors 46 and 47. It is determined whether or not the differential pressure δp of the brake oil pressure exceeds a predetermined reference value p ₀ . In this case, when the pressure difference δp exceeds a predetermined reference value p ₀ is the same manner as described above the split control flag F _S is set to 1, so that the split control is performed.

Next, the operation of this embodiment will be described.

[0052] First, as shown in FIG. 8, in a state left rear wheel speed V _RL is there is little difference between the average front wheel speed V _F, the right rear wheel speed V
_{When RR} exceeds the engine control target value S _E (t ₄ ), the second spin flag F ₂ is set to 1. In this case,
Since the left rear wheel speed V _RL is stuck to the average front wheel speed V _F, the first spin flag F ₁ is maintained at 0. Therefore, the split determination flag F _SP is set to 1 and the timer 51 starts counting up at the same time. At the time (t ₅ ) when the timer 51 counts up the predetermined lower limit value T ₁ , the differential pressure δp of the braking pressure supplied to the brake devices 13, 14 of the left and right rear wheels 3, 4 becomes equal to the reference value p. When it exceeds ₀ , the split control flag F _S is set to 1 and the control is switched from the normal control to the split control. That is, the subject time t ₅ from the engine control target value S _E increases by a predetermined amount.
In this case, while the second slip value S ₂ for the right rear wheel 4 of the slip state exceeds a brake control target value S _B is braking to the brake device 14 via the wheel brake pressure supply line 20 after the other with braking force pressure is supplied to the right rear wheel 4 is applied, the first slip value S ₁ is a brake system of the left rear wheel 3 does not reach the brake control target value S _B 13
Is not supplied with a braking pressure and no braking force acts. As a result, the engine output in which the suppression state is alleviated by the increase of the engine control target value S _E is preferentially distributed to the left rear wheel 3, and the startability or the acceleration performance is improved. .

Then, in a state where the left rear wheel speed V _RL is stuck to the average front wheel speed V _F , the right rear wheel speed V _RR becomes equal to the engine control target value S.
_{When E} is interrupted, the value of the split determination flag F _SP is set to 2 and the timer 51 is switched from count up to count down from the time t ₆ while maintaining the split control flag F _S at 1.
In this embodiment, the gain for the countdown of the timer 51 is set to 0.5. That is, for example, when the timer 51 counts up for 5 seconds, the count value T _M becomes 0 only when the countdown is continued for 10 seconds, and the split control flag F _S is reset to 0.

[0054] In this case, the count value T _M again right rear wheel speed V _RR in until 0 of the timer 51 exceeds the engine control target value S _E, a split determination flag F _SP is set to 1 together, the timer 5 to the time t ₇
1 restarts counting up. As a result, the right rear wheel 4
Responsiveness of the split control when re-spins.

On a low μ road surface, the left and right rear wheels 3 and 4 may alternately slip as shown in FIG. 9, but at this time, for example, as shown in the figure, the left rear wheel speed after the V _RL is interrupted the engine control target value S _E, there is a case where the right rear wheel speed V _RR in the next sampling exceeds the engine control target value S _E. In this case, from the point of view of phenomena, from the time (t ₈ ) at which the rear left wheel speed V _RL falls below the engine control target value S _E , the time when the right rear wheel speed V _RR exceeds the engine control target value S _E (t ₉₎ until both of the right and left rear wheels 3, 4 is rendered non-slip state, the slipping state of the right rear wheel 4 at the time when the right rear wheel speed V _RR exceeds the engine control target value S _E (t ₉₎ since the second spin flag F ₂ showing a is set to 1, so that condition is satisfied determines that a split road surface is seemingly.

[0056] Therefore, in this example, 1 is compared with the sampling time δt before the last spin pattern P _^'SP and the current spin pattern P _SP during the split decision, on the opposite side of the rear wheel spin flag is inverted current when the rear wheel spins flags is set to 1, so as not to set a split determination flag F _SP to 1. That is, the first spin flag F ₁ is 0 indicating a slip condition of the left rear wheel 3 in the time t _9, the second spin flag F ₁ indicating a slip condition of the right rear wheel 4 is set to 1 Therefore, the current spin pattern P _SP is set to 2 according to the map of FIG. On the other hand, at time t ₈ one sampling time δt before, the second spin flag F ₂ indicating the slip state of the right rear wheel 4 is 0, and the first spin flag F ₂ indicating the slip state of the left rear wheel 3 is 1 since it was set to the previous spin pattern P _^'SP according to the map it is stored in the memory 50 in a state of being set to 1. Therefore, the ECU 40 determines that both the patterns P ^′
_SP and P _SP are compared with the split determination map shown in FIG. 7, the value of the split determination flag F _SP is set to 0 indicating a non-split state, and the routine proceeds from step S4 to step S5 in the flowchart of FIG. Will be executed. As a result, it is not necessary to determine that the road is a split road even though the road is not a split road, and a good determination accuracy can be obtained.

[0057]

As described above, according to the present invention, the spin patterns are sequentially determined in accordance with the spin states of the left and right driving wheels periodically detected by the first and second spin detecting means, respectively. Since the split determination is performed from the previous spin pattern and the current spin pattern in accordance with a preset split determination rule, it is possible to control the driving force appropriately reflecting various road surface conditions.

In particular, according to the second aspect of the present invention, the split determination rule is set so that when one of the left and right drive wheels is in the spin state last time, the split determination is performed even if both drive wheels are in the non-spin state this time. Therefore, even when the spin state temporarily stops, the state is not determined to be the non-split state, whereby accurate split determination is performed.

According to the third aspect of the present invention, when one of the left and right driving wheels is in the spin state last time when the left and right driving wheels indicate the non-spin state, the end time of the split determination is delayed. Therefore, the responsiveness of the split control at the next spin is improved.

According to the fourth aspect, the delay time of the end time of the split determination is set according to the time of the split determination, so that the responsiveness of the split control at the next spin is further improved. become.

According to the fifth aspect of the present invention, when one of the left and right drive wheels is in a spin state last time and the other drive wheel is in a spin state next time, one of the drive wheels becomes non-active this time. Since it is set not to perform the split determination even in the spin state, there is no erroneous determination that the vehicle is on the split road surface even though the vehicle is not on the split road surface, whereby accurate split determination is performed.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing a basic configuration of a first invention.

FIG. 2 is a control system diagram of the vehicle.

FIG. 3 is a flowchart showing basic traction control.

FIG. 4 is a time chart illustrating a control mode of normal traction control.

FIG. 5 is a flowchart illustrating a split determination process.

FIG. 6 is an explanatory diagram showing an example of a spin pattern map used in the determination processing.

FIG. 7 is an explanatory diagram showing an example of a split determination map similarly used in the determination processing.

FIG. 8 is a time chart illustrating the operation of the present embodiment.

FIG. 9 is a time chart showing the operation of the embodiment.

[Explanation of symbols]

 1, 2, front wheel 3, 4 rear wheel 5 engine 8 differential 40 ECU 41-44 wheel speed sensor 50 memory 51 timer

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Makoto Kawamura 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (56) References JP-A-3-82657 (JP, A) JP-A-2 -254033 (JP, A) JP-A-2-252930 (JP, A) JP-A-2-22633 (JP, A) JP-A-60-128028 (JP, A) JP-A-2-41962 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B60K 41/20 B60T 8/58 F02D 29/02 311 F02D 45/00 314 F02D 45/00 345

Claims (5)

(57) [Claims] A driving force distributing means for distributing engine output to left and right driving wheels is provided on a power transmission path from an engine to left and right driving wheels, and a driving force for controlling a driving force according to a slip state of the driving wheels. A vehicle slip control device provided with force control means, comprising: first and second spin detection means for periodically detecting spin states of left and right drive wheels, respectively, and the first and second spin detection means A spin pattern determining means for sequentially determining the spin patterns of the driving wheels based on the detected spin states of the left and right driving wheels, and a previous spin pattern and a current spin pattern determined by the spin pattern determining means, Split determination means for performing a split determination on a road surface on which each of the drive wheels contacts the ground according to a preset split determination rule. A slip control device for a vehicle. 2. A drive system for distributing engine output to left and right drive wheels in a power transmission path from an engine to left and right drive wheels, and controlling drive force in accordance with a slip state of the drive wheels. A vehicle slip control device provided with force control means, comprising: first and second spin detection means for periodically detecting spin states of left and right drive wheels, respectively, and the first and second spin detection means A spin pattern determining means for sequentially determining the spin patterns of the driving wheels based on the detected spin states of the left and right driving wheels, and a previous spin pattern and a current spin pattern determined by the spin pattern determining means, Split determination means for performing a split determination on a road surface on which each of the drive wheels contacts the ground according to a preset split determination rule. And the above-described determination rule is set so that when one of the left and right driving wheels is in the spin state last time, the split determination is performed even when both of the driving wheels are in the non-spin state this time. apparatus. 3. A driving force distributing means for distributing an engine output to the left and right driving wheels on a power transmission path from the engine to the left and right driving wheels, and controlling the driving force according to a slip state of the driving wheels. A vehicle slip control device provided with force control means, comprising: first and second spin detection means for periodically detecting spin states of left and right drive wheels, respectively, and the first and second spin detection means A spin pattern determining means for sequentially determining the spin patterns of the driving wheels based on the detected spin states of the left and right driving wheels, and a previous spin pattern and a current spin pattern determined by the spin pattern determining means, Split determining means for performing split determination on a road surface on which each of the drive wheels touches the ground according to a preset split determination rule; In the case where the spin state of the left and right drive wheels detected by the second detection means indicates the non-spin state of both drive wheels, the split by the split determination means may be performed when one of the left and right drive wheels is in the spin state last time. And a delay unit for delaying the end time of the determination. 4. A driving force distributing means for distributing an engine output to the left and right driving wheels in a power transmission path from the engine to the left and right driving wheels, and controlling the driving force according to a slip state of the driving wheels. A vehicle slip control device provided with force control means, comprising: first and second spin detection means for periodically detecting spin states of left and right drive wheels, respectively, and the first and second spin detection means A spin pattern determining means for sequentially determining the spin patterns of the driving wheels based on the detected spin states of the left and right driving wheels, and a previous spin pattern and a current spin pattern determined by the spin pattern determining means, Split determining means for performing split determination on a road surface on which each of the drive wheels touches the ground according to a preset split determination rule; In the case where the spin state of the left and right drive wheels detected by the second detection means indicates the non-spin state of both drive wheels, the split by the split determination means may be performed when one of the left and right drive wheels is in the spin state last time. A vehicle slip control device comprising: delay means for delaying the end time of the determination; and delay time setting means for setting a delay time for the delay means in accordance with the split determination time in the determination means. . 5. A driving force distributing means for distributing an engine output to the left and right driving wheels in a power transmission path from the engine to the left and right driving wheels, and controlling the driving force according to a slip state of the driving wheels. A vehicle slip control device provided with force control means, comprising: first and second spin detection means for periodically detecting spin states of left and right drive wheels, respectively, and the first and second spin detection means A spin pattern determining means for sequentially determining the spin patterns of the driving wheels based on the detected spin states of the left and right driving wheels, and a previous spin pattern and a current spin pattern determined by the spin pattern determining means, Split determination means for performing a split determination on a road surface on which each of the drive wheels contacts the ground according to a preset split determination rule. And, when one of the left and right drive wheels is in the spin state last time and the other drive wheel is in the spin state next time, the split determination should be performed even if the one drive wheel is in the non-spin state this time. A slip control device for a vehicle, wherein the slip control device is set.