JP2003343306A - Driving force control device of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To carry out accurate traction control. <P>SOLUTION: A friction coefficient μ on a road is calculated at slip generation of a driving wheel, and when μ is equal to or smaller than a set value μ<SB>0</SB>, under a condition that a second throttle valve provided serially with respect to a throttle valve is fully opened, a requested fuel cut amount in response to a slip state is calculated, and the number of cylinders fuel cut corresponding to the calculated value is performed (S1 to S4 → S6, S7). When μ is larger than the set value μ<SB>0</SB>, under a condition that the second throttle valve is maintained to be fully opened state, control of the number of cylinders in fuel cut is performed in response to the slip state (S3 → S5 to S7). <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving force (traction) control device for a vehicle.

[0002]

2. Description of the Related Art On a slippery road surface such as a wet asphalt road or a snowy road, the drive wheels slip during acceleration, and the vehicle cannot be accelerated sufficiently, or the tail swings to lower the stability.

Therefore, when the occurrence of slip is detected on the basis of the rotational speed difference between the driving wheel and the driven wheel, the vehicle driving force control device closes a throttle valve provided in the intake passage of the engine to drive the driving force. By reducing the (engine torque), there are some that improve the starting performance and acceleration performance, and improve the vehicle stability by preventing the tail swing.

[0004]

However, in such a conventional vehicle driving force control system, if the closing degree of the throttle valve is set too small, slippage occurs on a road surface having a relatively large friction coefficient. In case of
Since the driving force is reduced more than necessary, the acceleration performance when accelerating after slip is avoided is impaired. On the other hand, if the opening degree of the throttle valve is set too large, on the contrary, it becomes impossible to sufficiently reduce the driving force on a snowy road surface or the like having a small friction coefficient (see FIG. 8).

On the other hand, when there is a large driver's acceleration demand, such as when the vehicle exits the stack, the throttle valve is closed due to the occurrence of slip and the engine output is greatly reduced.

The present invention has been made in view of the above points, and by appropriately combining the driving force control by the throttle valve and other driving force control, a good driving force for a road surface having a different friction coefficient is obtained. It is an object of the present invention to provide a driving force control device for a vehicle that can perform control.

[0007]

For this reason, the invention according to claim 1 is directed to a throttle valve arranged in an intake passage of an engine, a slip state detecting means for detecting a slip state of a drive wheel of a vehicle, and a detecting state. First driving force reduction control means for controlling the closing of the throttle valve to reduce the driving force of the vehicle according to the slip state, road surface state detecting means for detecting a friction coefficient state of the vehicle traveling road surface, and Second driving force reduction control means for reducing the driving force of the vehicle with better responsiveness than the first driving force reduction control means, and driving force reduction control limiting means for limiting the operation of the first driving force reduction control means. When,
In a road surface state having a high friction coefficient, the driving force reduction control limiting means limits the operation of the first driving force reduction control means, and the necessary driving force reduction control is performed by the second driving force reduction control means. It is characterized by being covered by.

The invention according to claim 2 is characterized in that the second driving force reduction control means can be used in combination with the first driving force reduction control means. Further, the invention according to claim 3 is characterized in that, in a road surface state with a high friction coefficient, the driving force reduction control is performed only by the second driving force reduction control means.

According to a fourth aspect of the present invention, the road surface state detecting means detects at least one of a longitudinal acceleration and a lateral acceleration of the vehicle, and the road surface is detected based on the magnitude of the acceleration detected when the slip occurs. It is characterized by detecting the friction coefficient of.

According to a fifth aspect of the present invention, the road surface state detecting means estimates the driving force of the driving wheels estimated when the slip occurs, and the road surface friction is estimated based on the estimated driving force. It is characterized by detecting a coefficient.

Further, in the invention according to claim 6, the second
The driving force reduction control means is characterized in that it controls the number of cylinders for which fuel supply is stopped according to the slip state. Also, in the invention according to claim 7, the second driving force reduction control means calculates a required reduction amount of the fuel supply amount with respect to a deviation between the target slip amount and the detected slip amount, and the required reduction amount. It is characterized in that the number of cylinders for which fuel supply is stopped is controlled according to the amount.

In the invention according to claim 8, the driving force reduction control limiting means limits the operation by increasing the threshold value of the slip of the driving wheels on which the first driving force reduction control means operates. Characterize.

According to a ninth aspect of the present invention, the driving force reduction control limiting means relatively enhances the driving force reduction action of the second driving force control means, whereby the first driving force reduction control means is provided. It is characterized by limiting the operation of.

[0014]

According to the first aspect of the present invention, when the slip of the drive wheels is detected, the first drive force reduction control means controls the throttle valve to be closed according to the magnitude of the slip to control the drive force of the vehicle. Reduce and suppress slip. Here, when the friction coefficient of the traveling road surface is large, the operation of the first driving force reduction control means is limited, and the slip is suppressed by the second driving force reduction control means. Particularly, in the invention according to claim 2, the second driving force reduction control means can be used together with the first driving force reduction control means, and in the invention according to claim 3, the suppression of the slip is the second driving force. It is covered only by reduction control means.

That is, when the friction coefficient (μ) of the traveling road surface is large, the driving force required for accelerating again after slip is suppressed is large. In other words, in a high-μ road surface state where slip is unlikely to occur, the driving force of the vehicle immediately before the occurrence of slip is large, so the engine output required to return to this state is large.

When the first driving force reduction control means fully closes the second throttle valve in such a high μ road surface condition, the second throttle valve is fully opened at the time of re-acceleration after slip suppression. Even if it is returned, the increase in the engine output due to the increase in the intake air flow rate is large, so that it is difficult to ensure good acceleration, but the second driving force reduction control means reduces the driving force. In other words, at the time of the re-acceleration, the driving force can be increased with good responsiveness by releasing the operation of the second driving force reduction control means, and good acceleration performance can be obtained.
Although the first driving force reduction control means is inferior in response to the second driving force reduction control means, it controls the engine output by the original method of controlling the intake air flow rate. In terms of drivability (combustibility, etc.) and fuel consumption, it is superior to other methods that reduce the driving force (for example, fuel consumption deteriorates when braking is performed and only a gradual output reduction can be performed in a fuel cut cylinder). Basically, the first driving force reduction control means is used.

On the contrary, in the low μ road surface state where the frictional resistance is small,
If the engine output cannot be sufficiently reduced and the slip cannot be suppressed even if the throttle valve is closed by the second driving force reduction control means, the second driving force reduction control means is also used to reduce the insufficient driving force reduction amount. By reducing it, a good traction function can be obtained.

In the invention according to claim 4, the driving force of the vehicle that can travel without slipping on the traveling road surface increases as the friction coefficient of the road surface increases, and the driving force and the acceleration are proportional. The friction coefficient of the road surface can be detected based on the acceleration at the moment when the slip occurs.

Further, in the invention according to claim 5, the friction coefficient of the road surface can be detected based on the driving force of the driving wheels estimated for the above reason. Further, in the invention according to claim 6, the second driving force reduction control means controls the number of cylinders that stop the fuel supply according to the slip state, thereby gradually reducing the engine output and driving force. Can be reduced.

Further, in the invention according to claim 7, the setting of the number of cylinders for which fuel supply is stopped is set in accordance with the required reduction amount of the fuel supply amount calculated with respect to the deviation between the target slip amount and the detected slip amount. Therefore, it is possible to perform highly accurate driving force reduction control according to the slip state.

Further, in the invention according to claim 8, the driving force reduction control limiting means limits the operation by a simple method of increasing the threshold value of the slip of the driving wheels operated by the first driving force reduction control means. can do.

Further, in the invention according to claim 9, the driving force reduction control limiting means makes it difficult for slip to occur due to the driving force reducing action of the second driving force control means, thereby reducing the first driving force. The operating opportunity of the control means will be limited.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 is a system diagram of the entire vehicle, FIG.
FIG. 3 is a system diagram of a drive device for a second throttle valve. F
A normally open second throttle valve 4 is provided on the upstream side of a throttle valve 3 that is opened / closed in conjunction with an accelerator pedal in an intake passage 2 of an engine 1 that is arranged horizontally in an F car. A fuel injection valve 31 is provided for each cylinder.

On the other hand, the left and right front wheels (driving wheels) are provided with wheel speed sensors 5A and 5B, respectively, and the left and right rear wheels (driven wheels) are provided with wheel speed sensors 6A and 6B, respectively. It is input to the control unit 7.

The traction control unit 7 is
The occurrence of slip is detected based on the wheel speed difference between the driving wheel and the driven wheel, and a driving force reduction request signal is generated when the slip occurs. One of the driving force reduction request signals is sent to the driving device of the second throttle valve 4 (more specifically, a three-way solenoid valve 21 described later), which drives the second throttle valve 4 in the valve closing direction. In addition, other signals of the driving force reduction request signal are sent to the engine control module 8 and control such as fuel cut of the number of cylinders corresponding to the required reduction driving force is performed. Further, in order to estimate the friction coefficient μ of the traveling road surface, in order to detect the acceleration in the traveling direction of the vehicle when the slip of the drive wheels occurs, the longitudinal G sensor 32 for detecting the longitudinal acceleration and the lateral G sensor 32
A lateral G sensor 33 for detecting (lateral) directional acceleration is provided, and these signals are also input to the traction control unit 7. On the other hand, a throttle sensor 34 for detecting the opening of the throttle valve 3 is provided, and a signal from the throttle sensor 34 is input to the engine control module 8 for engine control, and the second throttle valve 4 is closed under a predetermined condition described later. The signal is input from the engine control module 8 to the traction control unit 7 as a signal for setting a condition for prohibiting.

Next, the drive device for the second throttle valve 4 will be described. The second throttle valve 4 has a valve shaft 11 at a position eccentric from the center of a resin chamber 10 that constitutes the intake passage.
A butterfly valve with a lever fixed to the valve shaft 11.
It is opened and closed by 12 operations. For this lever 12,
Stoppers 13 and 14 are provided so as to regulate the swinging range thereof, whereby the second throttle valve 4 can take a fully open position and a fully closed position of about 1/8 opening. ing.

An output rod 17 connected to a diaphragm 16 of a negative pressure diaphragm device 15 is connected to the lever 12 of the second throttle valve 4. Negative pressure diaphragm device 15,
A negative pressure working chamber 18 defined by the diaphragm 16 and a spring 19 which is housed in the negative pressure working chamber 18 and urges the diaphragm 16 are provided. When the negative pressure is introduced into the negative pressure working chamber 18, the diaphragm 16 is moved. In the figure, it is displaced to the right and the second throttle valve 4
Is driven to the fully closed position, and the atmosphere is introduced into the negative pressure operation chamber 18, whereby the diaphragm 16 is displaced leftward in the drawing, and the second throttle valve 4 is returned to the fully opened position.

A three-way solenoid valve 21 for selectively introducing negative pressure or atmospheric pressure is connected to a communication passage 20 of the negative pressure diaphragm device 15 to the negative pressure operating chamber 18. Three-way solenoid valve 21 is off
In the state, the negative pressure side port P ₁ is closed and the atmospheric pressure side port P ₂ is opened, and in the ON state, conversely, the atmospheric pressure side port P ₂
Is closed, and the negative pressure side port P ₁ is opened.

Negative pressure side port P of the three-way solenoid valve 21₁ Is negative pressure
It is connected to the negative pressure tank 23 by the introduction passage 22, and this negative pressure tank 23
Intake manifold (intake manifold) via check valve 24.
It is connected to the throttle valve 3 downstream of the passage 2. Three sides
Atmospheric pressure side port P of solenoid valve 21 ₂In the atmospheric pressure introduction passage 25
Although it is open to the atmosphere, it does not move in the atmospheric pressure introduction passage 25.
An orifice 26, which is one of the means for defining the working time, is provided
There is.

As described above, by using the negative pressure diaphragm device as the drive device for switching the second throttle valve 4 between the two stages of full opening and full closing, a significant cost reduction can be achieved as compared with the conventional DC motor. In addition to the negative pressure diaphragm device, for example, a solenoid actuator that strokes a certain amount may be used, and this device can also reduce the cost as compared with a DC motor.

Next, the basic operation of the first driving force reduction control means including the second throttle valve 4 and its drive device will be described. During normal operation, the three-way solenoid valve 21 is in the OFF state, the negative pressure side port P ₁ is closed, and the atmospheric pressure side port P ₂ is opened. Therefore, the atmospheric pressure is introduced into the negative pressure working chamber 18 of the negative pressure diaphragm device 15, and the diaphragm 16 is displaced leftward in FIG. 2 by the spring 19 to hold the second throttle valve 4 in the fully open position. ing. The fully open position referred to here is an opening that can secure the required air amount of the engine.

On the other hand, the traction control unit 7 calculates the difference between the wheel speed detected by the wheel speed sensors 5A, 5B on the front wheel side and the wheel speed detected by the wheel speed sensors 6A, 6B on the rear wheel side. When this difference exceeds a predetermined value, it is determined that slip has occurred, and a driving force reduction request signal is output.

This signal causes the three-way solenoid valve 21 to change from the OFF state to the ON state, and in the three-way solenoid valve 21, the atmospheric pressure side port P ₂ is closed and the negative pressure side port P ₁ is opened. Therefore, negative pressure is introduced into the negative pressure operation chamber 18 of the negative pressure diaphragm device 15, and the diaphragm 19 resists the biasing force of the spring 19.
Displace 16 to the right in FIG. 2 and set the second throttle valve 4 to 1
Drive to the fully closed position of about / 8 opening.

By setting the opening at the fully closed position to about 1/8, the engine can be restrained to a small opening necessary for suppressing slip and prevent engine stall. Further, at this time, the operation time from the fully open position to the fully closed position (t _{1 in} FIG. 3) depends on the effective pressure receiving area of the diaphragm 16, the passage diameter of the negative pressure introducing passage 22, and the like, even if slipping occurs on a low μ road. To be able to hold it down early, set it to an extremely short time of 0.2 seconds or less.

When the driving force is reduced by such a closing operation of the second throttle valve 4 and the slip ratio decreases, the driving force reduction request signal from the traction control unit 7 is released.

By releasing this signal, the three-way solenoid valve 21 is turned on.
The state is changed to the OFF state, and in the three-way solenoid valve 21, the negative pressure side port P ₁ is closed and the atmospheric pressure side port P ₂ is opened.
Therefore, atmospheric pressure is introduced into the negative pressure operating chamber 18 of the negative pressure diaphragm device 15, and the diaphragm 19 displaces the diaphragm 16 leftward in FIG. 2 to return the second throttle valve 4 to the fully open position.

At this time, the operating time from the fully closed position to the fully open position (t _{2 in} FIG. 3) is higher than the passage resistance of the negative pressure introduction passage 22 by providing the orifice 26 on the atmosphere introduction passage 25 side, By increasing the resistance, it is set to 2 to 7 seconds, which is more than 10 times the operation time from the fully open position to the fully closed position.
This is to suppress the feeling of rushing when changing from a low μ road to a high μ road.

In the present embodiment, when the negative pressure disappears for some reason, the negative pressure working chamber 18 of the negative pressure diaphragm device 16 becomes atmospheric pressure, but at this time, the second throttle valve 4 is fully opened. Take a position. Therefore, it becomes possible to travel even in the event of such a failure.

Further, when the second throttle valve 4 becomes free due to the lack of the output rod 17 of the negative pressure diaphragm device 15, the valve shaft 11 of the second throttle valve 4 is eccentric from the center of the intake passage. Since there is a difference in the pressure receiving areas of the left and right valve bodies with the valve shaft 11 sandwiched between them, even if the second throttle valve 4 tries to close,
Due to the pressure difference on the downstream side (negative pressure on the downstream side), a moment in the valve opening direction acts on the second throttle valve 4. Therefore, even in the event of such a failure, the second throttle valve 4 can be opened to allow traveling.

Next, the first driving force reduction control means that basically operates as described above and the second driving force that controls the number of cylinders that stop the fuel supply according to the slip state to reduce the driving force. The driving force reduction control (traction control) that also uses the reduction control means will be described with reference to the flowcharts of FIGS. FIG. 4 shows an example of the driving force reduction control.

Step (denoted by S in the figure. The same applies hereinafter) 1
Then, as described above, it is determined from the difference in wheel speed between the front wheels and the rear wheels whether or not slip is occurring. When it is determined that the slip has not occurred, the second throttle valve 4 is kept fully open in step 8 and this routine is ended.

When the occurrence of slip is detected, the routine proceeds to step 2, where the longitudinal acceleration Xg detected by the longitudinal G sensor 32 and the lateral (lateral) acceleration Yg detected by the lateral G sensor 33 are detected. Based on the friction coefficient μ of the road surface as a value proportional to the magnitude of acceleration in the vehicle traveling direction.
Calculate {= k · (X ² + Yg ² ) ^1/2 }. Here, the front and rear G sensor 32, the lateral G sensor 33 and the function of the step 2 constitute a road surface state detecting means.

In this embodiment, the longitudinal G sensor 32 and the lateral G sensor 33 are provided to detect the acceleration. For example, the longitudinal acceleration Xg is the acceleration of the driven wheel speed (obtained by the amount of change per unit time). The lateral acceleration Yg is calculated from the difference between the left and right driven wheel speeds {Yg = | V _FL −V _FR | ・ (V _FL
−V _FR ) / 2 · α, VFL, VFR can be left and right driven wheel speeds, and α is a constant}.

Next, at step 3, the calculated friction coefficient μ of the road surface is compared with the set value μ ₀ for magnitude comparison. Here, the set value μ ₀ is set to, for example, a value (about 0.35) corresponding to a snow-covered road surface, and the second throttle valve 4
The opening degree of ⅛ of the fully closed state is set to the upper limit opening degree that allows grip running with slip suppressed on the road surface having the friction coefficient μ ₀ .

When it is determined in step 3 that the detected value μ of the road surface friction coefficient is less than or equal to the set value μ ₀ , step 4
And the three-way solenoid valve 21 is turned on and the second throttle valve 4
Is fully closed. That is, the second throttle valve 4 and its drive device and the function of the step 4 constitute the first drive force reduction control means.

As a result, as described above, the friction coefficient μ ₀
The engine output and thus the driving force of the vehicle are reduced to such an extent that grip traveling on a road surface having the above is possible. Further, the process proceeds to step 6 and step 7 to perform the second driving force reduction control for controlling the number of cylinders for which the fuel cut is performed according to the slip state. That is, the functions of step 6 and step 7 constitute second driving force reduction control means.

Specifically, a target value of slip for optimum running is set, the required fuel cut amount C is calculated by PID control according to the deviation ε from the slip detected in step 6, and in step 7, The number of cylinders corresponding to the calculated value is cut. The required fuel cut amount C is calculated by the following equation.

C = kP.ε + kI.∫εdt + kD ・ dε
/ dt, (kP, kI, kD are gains for P minutes, I minutes, and D minutes) That is, when the friction coefficient μ of the road surface is smaller than the set value μ 0, the slip is larger than the target value. Therefore, by performing the feedback control to reduce the fuel supply amount by that amount and reduce the driving force of the vehicle, it is possible to travel with the optimal driving force while maintaining the slip near the target value.

When it is determined in step 3 that the friction coefficient μ of the road surface is larger than the set value μ _{0, the} routine proceeds to step 5, where the second throttle valve 4 is held fully open and the routine proceeds to step 6. The determination function in step 3 and the function of keeping the second throttle valve 4 fully open in step 5 constitute the driving force reduction control limiting means.

Then, in the same manner as described above, the required fuel cut amount C is calculated by PID control, and in step 7, the number of cylinders corresponding to the calculated value is cut. In this case, the driving force of the vehicle is controlled only by the fuel cut control. That is, when the second throttle valve 4 is closed on a road surface having a friction coefficient μ larger than the set value μ _0, the driving force of the vehicle is reduced more than necessary, and the vehicle travel is restricted to a low vehicle speed with a slip ratio smaller than the target value. Further, thereafter, even when the second throttle valve 4 is switched to the full open when the slip state is avoided and the re-acceleration is performed, the delay of the increase of the engine output due to the delay of the increase of the intake air flow rate is large, and the sufficient acceleration performance is obtained. Cannot be secured.

Therefore, by performing only the fuel cut control on such a high μ road, it is possible to run at a vehicle speed as high as possible while maintaining the slip near the target value when a slip occurs.
Further, when the slip is avoided and the re-acceleration is performed thereafter, the engine output can be quickly raised by stopping the fuel cut, and good acceleration performance can be obtained.

As the second driving force reduction control means which is more responsive than the first driving force reduction control means, in addition to the above fuel cut cylinder number control, another engine output control such as ignition timing retard Control (however, if the retardation is too large, the combustibility deteriorates, so it is preferable to use a method that reduces the output very finely in combination with the fuel cut cylinder number control) or downshift of the automatic transmission. Control or control for increasing the braking force (In these cases as well, the required driving force decrease amount equivalent to the required fuel cut amount C may be calculated, and the control may be performed so that the gear ratio and the braking force match the calculated value. ) You may.

Although the friction coefficient μ of the road surface is obtained from the acceleration of the vehicle in this embodiment, it may be obtained from the driving force of the drive wheels when a slip occurs. FIG. 5 is a flowchart of an embodiment in which the driving force control is performed according to the road surface friction coefficient estimated from the driving force of the driving wheels instead of the method of directly calculating the road surface friction coefficient. It shows the part replaced with.

That is, in step 11, the error when slip occurs
Engine output torque T_E Is the basic fuel injection amount T_P Estimated by
Then, in step 12, the estimated output torque T_E Transmission
Gear ratio N_T And the final reduction gear ratio N_F And drive wheels
Output torque T_D To calculate. In step 13, the output
Luk T_D Set value T_S Compare the size relationship with_D ≤T _S 
If it is determined that the second step
Control the number of fuel cut cylinders after closing the throttle valve.
Yes, T_D > T_S If it is determined that the step 5 or later
Therefore, keep the second throttle valve 4 fully open to prevent fuel cut.
Only the cylinder number control is performed. Here, the set value T_S Is the fruit
Example road friction coefficient set value μ₀Sliding on the road surface with
Output torque of the drive wheels that enables grip running with suppressed
It is set to correspond to the quota value.

Therefore, the same driving force control as in the case of controlling the friction coefficient μ by comparing it with the set value μ ₀ in the above embodiment is performed. Figure 6 shows the road friction coefficient μ
An embodiment of the driving force control in which the operation of the first driving force reduction control unit is limited by changing the threshold value of the slip that determines whether or not the first driving force reduction control unit is operating The flowchart of (Examples according to claims 9 and 10) is shown for a portion replaced with step 3 in FIG. A part of the flowchart is shown.

That is, in step 2 of FIG. 4, the road surface friction coefficient μ
After calculating, the process proceeds to step 21, and a slip threshold value S ₀ that determines whether or not there is a driving force reduction control by the second throttle valve, which will be described later, is set according to the calculated friction coefficient μ. Here, the threshold value S ₀ is set to a larger value as the friction coefficient μ increases as shown in the figure.

In step 22, the magnitude relationship between the detected value S of the slip and the threshold value S ₀ is compared, and if S> S ₀ , the process proceeds to step 4 in FIG. 4 and after the second throttle valve 4 is closed. In step 5, the fuel cut cylinder number control is performed, and S ≦ S
When it is ₀ , the fuel cut cylinder number control is performed in step 5 while keeping the second throttle valve 4 fully open.

In this way, the larger the road surface friction coefficient μ, the more difficult it becomes to perform the driving force reduction control for closing the second throttle valve by the first driving force reduction control means. In addition,
Similarly, the necessary driving force reduction control is covered by the second driving force reduction control means such as the fuel cut cylinder number control.

FIG. 7 is a flow chart of an embodiment in which the operation of the first driving force reduction control means is limited by changing the degree of the driving force reduction action by the second driving force reduction control means. 4 shows the part replaced with step 3 of 4.

In step 31, the control gain k _P for P in the PID control when the required fuel cut amount C is calculated as described above when performing the fuel cut cylinder number control according to the slip state is set according to the friction coefficient μ. To set. Here, the gain k _P is set to a larger value as the friction coefficient μ increases as shown in the figure. In step 32, the magnitude relation between the detected value S of the slip and the threshold value S ₀ is compared, and when S> S ₀ is the same as above, the process proceeds to step 4 of FIG. 4 and the second throttle valve 4 is closed. 5, the fuel cut cylinder number control is performed, and when S ≦ S ₀ , the fuel cut cylinder number control is performed in step 5 while keeping the second throttle valve 4 fully open.

In this way, as the road surface friction coefficient μ increases, the control gain k _P of the proportional amount P increases, and the required fuel cut amount C increases for the same slip value. Since the number of fuel cut cylinders increases and the driving force is reduced, the slip is suppressed, and the operation of the first driving force reduction control executed in the determination of step 32 is relatively limited. That is, even in this case, the same function as that of the above-described embodiment can be achieved.

[0062]

As described above, according to the invention of claim 1, when the friction coefficient of the road surface is large,
The operation of the first drive force reduction control means can be limited to ensure good performance at the time of reacceleration, and when the friction coefficient is small, the second drive force reduction control means is also used to reduce the drive force sufficiently. Thus, slip can be suppressed and traction control as good as possible can be performed.

[Brief description of drawings]

FIG. 1 is a system diagram of an entire vehicle showing an embodiment of the present invention.

FIG. 2 is a system diagram of a drive device for a second throttle valve in the above embodiment.

FIG. 3 is a diagram showing operating time characteristics.

FIG. 4 is a flowchart showing a first example of driving force control according to the embodiment.

FIG. 5 is a flowchart showing the main part of the second example.

FIG. 6 is a flow chart showing the main part of the third example.

FIG. 7 is a flow chart showing a main part of the fourth example.

FIG. 8 is a diagram showing an operation of simple traction control.

[Explanation of symbols]

1 engine 2 Intake passage 3 Throttle valve 4 Second throttle valve 5A, 5B Wheel speed sensor 6A, 6B Wheel speed sensor 7 Traction control unit 8 Engine control module 10 chamber 15 Negative pressure diaphragm device 31 Fuel injection valve 32 front and rear G sensor 33 Horizontal G sensor

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02D 43/00 F02D 43/00 301K F term (reference) 3D041 AA48 AB01 AC01 AC04 AD04 AD51 AE04 AE06 AE07 AE08 AF01 3G084 BA02 BA05 BA13 CA04 DA17 EA11 EB12 EC03 FA04 FA05 FA10 3G093 AA01 BA01 CB05 DA06 DB03 DB04 DB05 DB21 EA05 EA08 EA10 EC01 FA07 FA11 FB02 3G301 HA01 HA06 JA38 KB01 LA02 LA03 AZ02 NE06 Z11 ND02

Claims (9)

[Claims] 1. A throttle valve arranged in an intake passage of an engine, a slip state detecting means for detecting a slip state of a drive wheel of a vehicle, and a throttle valve closed control according to the detected slip state. First driving force reduction control means for reducing the driving force of the vehicle, road surface state detection means for detecting the state of the friction coefficient of the vehicle traveling road surface, and driving of the vehicle with better response than the first driving force reduction control means. A driving force reduction control means for controlling the reduction of force, and a driving force reduction control limiting means for limiting the operation of the first driving force reduction control means. A driving force control device for a vehicle, wherein the force reduction control limiting means limits the operation of the first driving force reduction control means, and the necessary driving force reduction control is covered by the second driving force reduction control means. . 2. The vehicle driving force control device according to claim 1, wherein the second driving force reduction control means can be used together with the first driving force reduction control means. 3. The vehicle driving force control according to claim 1, wherein the driving force reduction control is performed only by the second driving force reduction control means in a road surface state having a high friction coefficient. apparatus. 4. The road surface state detecting means detects at least one of a longitudinal acceleration and a lateral acceleration of the vehicle, and detects a friction coefficient of the road surface based on the magnitude of the acceleration detected when a slip occurs. The driving force control device for a vehicle according to any one of claims 1 to 3, which is characterized. 5. The road surface state detecting means estimates the driving force of the driving wheels estimated when a slip occurs, and detects the friction coefficient of the road surface based on the estimated driving force. The driving force control device for a vehicle according to any one of claims 1 to 4. 6. The second driving force reduction control means controls the number of cylinders for which the fuel supply is stopped according to the slip state, according to any one of claims 1 to 5. Vehicle driving force control device. 7. The second driving force reduction control means calculates a required reduction amount of a fuel supply amount with respect to a deviation between a target slip amount and a detected slip amount, and a fuel corresponding to the required reduction amount is calculated. The driving force control device for a vehicle according to claim 6, wherein the number of cylinders whose supply is stopped is controlled. 8. The driving force reduction control limiting means limits the operation by increasing the threshold value of the slip of the driving wheels on which the first driving force reduction control means operates. Item 7. A vehicle driving force control device according to any one of items 7. 9. The driving force reduction control limiting means limits the operation of the first driving force reduction control means by relatively increasing the driving force reducing action of the second driving force control means. The driving force control device for a vehicle according to any one of claims 1 to 7.