JPH02157440A - Control device for slip of drive wheel - Google Patents

Abstract

PURPOSE:To eliminate abrupt drop of output by stopping feedback of exhaust gas when the slip value exceeds No.1 specified value, making lean the air fuel ratio for all cylinders, and cutting fuel supply to cylinders in a number according to slip value when No.2 specified value is exceeded. CONSTITUTION:A drive wheel slip sensor circuit 30 senses excessive slip of a drive wheel form signals given by drive/follower wheel revolving speed sensors 31-34 and a steering sensor 35. An engine control device 5 stops feedback of the exhaust gas being made by an exhaust gas feedback mechanism 20 when the slip value exceeds No.1 specified value and makes lean the air fuel ratio of the mixture to be supplied to all cylinders of an engine 1 on the basis of the fundamental fuel amount for control of drive wheel slip. When a further increase generates exceeding of No.2 specified value, fuel cut is made for cylinders in the number according to the slip value, and the air fuel ratio to the other cylinders is made lean. When the slip value exceeds the No.1 specified value, accelerative incremental correction is stopped. Thus shock is eliminated due to abrupt drop of output, and exhaust gas purifying device is prevented from drop of the performance.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a drive wheel slip control device for a vehicle, and more particularly to a drive wheel slip control device applied to a vehicle equipped with an exhaust gas recirculation device.

(Prior art) Generally, when a vehicle starts or accelerates, the driving force of the driving wheels increases the frictional force between the tires and the road surface [friction coefficient between the tires and the road surface x the load of the vehicle weight on the driving wheels (vehicle load)]. If exceeded, the drive wheels will slip.

The degree of this slip is detected by the difference ΔV between the driving wheel speed and the driven wheel speed of the vehicle, and when an excessive slip condition is detected where V increases to the wheel speed deviation, the wheel speed deviation increases as V increases. A drive wheel slip control device that reduces the amount of fuel supplied to the engine in stages in the order of ■ to ■ below to prevent vibration caused by a sudden drop in engine output torque has been known (especially 1978
Publication No. 8436).

■ Make the mixture supplied to the first cylinder lean (reduce the amount of fuel supplied).

■ Cut off the fuel supply to the first cylinder (perform a twin cylinder cut).

■ Cut off the fuel supply to the first cylinder, and
The air-fuel mixture supplied to the cylinders is made leaner.

■ Cut off the fuel supply to the first and second cylinders.

■ Cut off the fuel supply to the first and second cylinders, and make the mixture supplied to the third cylinder lean.

■ Cut off the fuel supply to the first, second, and third cylinders.

,・ (I!1! Problem that the invention seeks to solve) Excessive slip of the driving wheels can occur over a short period of time as sudden excessive slip, especially on road surfaces with a small coefficient of friction (for example, road surfaces during rainy weather). Therefore, according to the conventional control device described above, control is performed to immediately shift from, for example, the normal fuel supply state to the state (2), or from (2) to (2).

On the other hand, in the case of an engine that injects fuel into the intake pipe, there is residual fuel attached around the intake valve, and the amount of residual fuel depends on the amount of fuel injected fIj times.
This is especially true during acceleration when excessive slip occurs.

Therefore, in the conventional control device, when control is performed to immediately shift from the normal fuel supply state to the state (2) as described above, the first and second cylinders are in the normal fuel injection state,
In other words, a fuel cut is performed immediately when there is a large amount of residual fuel, and although the residual fuel is sucked into the cylinder, the air-fuel ratio is not high enough to burn it, and it is released into the atmosphere as unburned components, resulting in worsening exhaust gas characteristics. The problem arises that

Further, for example, in a case where there is an immediate transition from the normal fuel supply state to the state (2), this problem becomes more noticeable.

Furthermore, in the case of a vehicle equipped with an exhaust purification device using a catalyst in the exhaust system of the engine, a problem arises in that the unburned components are combusted within the exhaust purification device, deteriorating the purification performance of the exhaust purification device.

In addition, according to the conventional control device described above, for example, in the state (2) above, the first and second cylinders are twin-cut, but the other cylinders are supplied with the normal amount of fuel, so the output fluctuations for each cylinder are reduced. There is also the problem that the pulsation component of the engine torque increases as a result.

However, in a system that controls the drive wheel slip state by increasing or decreasing the amount of fuel supplied to the engine, a request is made to reduce engine output as the drive wheel slip state changes regardless of the engine operating state, but acceleration slip In order to avoid engine knocking and prevent high-temperature deterioration of the exhaust gas purification system at the same time as the engine is under high load, the air-fuel ratio during drive wheel slip control must be strictly set to a constant value on the lean side of the stoichiometric air-fuel ratio (for example, A /F#1
8 constant).

However, in the case of an engine equipped with an exhaust gas recirculation mechanism (hereinafter referred to as rEGRJ), if EGR is operated during lean control or twin cut control when the drive wheels are excessively slipping, the air-fuel ratio of the mixture supplied to the engine will be adjusted to the desired level. It is difficult to control the air-fuel ratio to , which leads to deterioration of exhaust gas characteristics. - The basic fuel quantity map for determining the amount of fuel supplied to the engine is set assuming EGR operation, so when stopping EGR operation, fuel is supplied based on the basic fuel quantity map. If the amount is determined, the air-fuel ratio of the air-fuel mixture cannot be appropriately controlled.

Furthermore, when the engine accelerates, the amount of fuel normally supplied to the engine is corrected to increase, but this also causes the air-fuel ratio to deviate from the desired value during drive wheel slip control.

The present invention has been made in view of the above-mentioned points, and eliminates the shock caused by a sudden drop in engine output when the drive wheels are in an excessive slip state, and further reduces the pulsating component of engine torque. Drive wheel slip not only prevents deterioration of exhaust gas characteristics due to residual fuel in the intake pipe and performance deterioration of the exhaust purification device, but also appropriately controls the air-fuel ratio of the air-fuel mixture supplied to the engine even when the drive wheels are in an excessive slip state. The purpose is to provide a control device.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a driving wheel speed sensor that detects the driving wheel speed of a vehicle, and detects excessive slip of the driving wheels based on the output of the driving wheel speed sensor. Excessive slip detection means outputs a slip value corresponding to the degree of excessive slip when the engine is overslipped, and fuel control means controls the amount of fuel supplied to an engine equipped with an exhaust gas recirculation mechanism according to the slip value. The wheel slip control device includes an exhaust recirculation stop means for stopping exhaust recirculation by the exhaust recirculation mechanism when the slip value is larger than a first predetermined slip value, and an air-fuel ratio that is substantially constant over the entire operating range of the engine. a storage means that stores a basic fuel amount for driving wheel slip control set to obtain the basic fuel amount for driving wheel slip control, and when the slip value is larger than the first predetermined slip value, based on the basic fuel amount for driving wheel slip control a fuel amount determining means for determining the amount of fuel to be supplied to the engine based on the slip value; and a fuel amount determining means for making the air-fuel ratio of the air-fuel mixture supplied to all cylinders lean when the slip value is larger than the first predetermined slip value. a fuel cutoff means for cutting off fuel supplied to a number of cylinders corresponding to the slip value when the slip value exceeds a second predetermined slip value that is larger than the first predetermined slip value; and second leanening means for leanening the air-fuel ratio of the air-fuel mixture supplied to cylinders other than the cylinders whose fuel supply is cut off by the fuel cutoff means when the slip value exceeds the second predetermined slip value. This is how it was done.

Further, it is possible to provide an increase correction stop means for stopping the increase correction of the fuel supply amount performed during engine acceleration and high load operation when the slip value described in 01j is larger than the first predetermined slip value. desirable.

(Function) When the slip value exceeds the first predetermined slip value, exhaust gas recirculation is stopped, the amount of fuel supplied to the engine is determined based on the basic fuel amount for driving wheel slip control, and all cylinders are The air-fuel ratio of the supplied air-fuel mixture is made lean. When the slip value further increases and exceeds a second predetermined slip value, fuel supply to the number of cylinders corresponding to the slip value is cut off, and the air-fuel ratio of the mixture supplied to the cylinders to which fuel supply is not cut off becomes lean. be converted into

Further, when the slip value exceeds the first slip value, the acceleration increase correction of the fuel supply amount is stopped.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an overall configuration diagram of an internal combustion engine equipped with an exhaust gas recirculation mechanism and its control device according to an embodiment of the present invention. For example, a throttle valve 3 is installed in the middle of an intake pipe 2 of a six-cylinder engine l. It is provided. A throttle valve opening (Oru) sensor 4 is connected to the throttle valve 3, and outputs an electric signal according to the opening of the throttle valve 3 to an electronic control unit for engine control (rENG).
-ECUJ) 5.

A fuel injection valve 6 is provided for each cylinder between the engine 1 and the throttle valve 3 and slightly upstream of an intake valve (not shown) in the intake pipe 2, and each injection valve is connected to a fuel pump (not shown). It is electrically connected to the ENG-ECU 5, and the valve opening time for fuel injection is controlled by a signal from the ENG-ECU 2.

The spark plug 16 provided for each cylinder of the engine 1 is E
It is electrically connected to NG-ECU5, and ENG-E
Ignition timing θ by CU5! 0 is controlled.

On the other hand, the intake pipe absolute pressure (
PB^) A sensor 7 is provided, and the absolute pressure signal converted into an electrical signal by the absolute pressure sensor 7 is sent to the ENG
- Supplied to ECU5. In addition, the intake temperature (
T^) A sensor 8 is installed, which detects the intake temperature 'l゛^ and outputs a corresponding electrical signal to the ENG-ECU 5.
supply to.

The temperature of the engine water installed in the main body of the engine ("I'w")
) The sensor 9 consists of a thermistor, etc., and detects the engine water temperature (cooling water temperature) Tw and outputs a corresponding temperature signal.
NC: - Supplied to ECU5.

Engine speed (Ne) sensor 10 and cylinder discrimination (CY)
L) The sensor 11 is attached around the camshaft or crankshaft (not shown) of the engine l. The engine rotation speed sensor lO outputs a pulse (hereinafter referred to as rTDc signal pulse J) at a predetermined crank angle position every 120 degree rotation of the crankshaft of the engine l, and is used as a cylinder discrimination sensor! l outputs a signal pulse at a predetermined crank angle position of a specific cylinder, and each of these signal pulses is sent to the ENG-ECU.
5.

The three-way catalyst 14 is arranged in the exhaust pipe 13 of the engine l and
It purifies components such as 11C, Go, and NOx in the exhaust gas. 02 sensor ■2 as exhaust gas concentration detector
is installed upstream of the three-way catalyst I4 of the exhaust gas [13], detects the oxygen concentration in the exhaust gas, outputs a signal according to the detected value, and supplies it to the ENG-ECU 5.

In addition, the ENG-ECU5 is equipped with an electronic control unit for detecting drive wheel slip (hereinafter ['C3-EC1J
J) 30 are connected. This i”CS
-E CU 30 includes a drive wheel speed sensor 3 that detects the rotational speed Wpg and WFL of left and right drive wheels (not shown).
1, 32, and the rotational speed W of the left and right driven wheels (not shown)
, Wu, and a steering sensor 35 that detects the turning angle δ of a steering wheel (not shown) are connected, and these sensors 31 to 35 receive their detection signals. Te3-E, CU3
Supply to O.

The steering sensor 35 calculates a positive angle (+1', +2', . . .) when steering to the right, and a negative angle (-1°, -2°, . .) when steering to the left, with the neutral point at zero degrees. This is a sensor that detects absolute angles.

Further, a battery voltage sensor 15 is connected to the ENG-EC (J5), and the battery voltage sensor 15 detects the battery voltage and supplies the detection signal to the ENG-ECU 5.

Next, the exhaust gas recirculation mechanism 20 will be explained.

The exhaust gas recirculation path 21 of this mechanism 20 has one end 21a communicating with the upstream side of the three-way catalyst 14 of the exhaust pipe 13, and the other end 21b communicating with the downstream side of the throttle valve 3 of the intake pipe 2. An exhaust gas recirculation valve 22 is interposed in the exhaust gas recirculation path 2 to control the amount of exhaust gas recirculation.

The exhaust gas recirculation valve 22 is operatively connected to a diaphragm 23a of a negative pressure response device 23.

The negative pressure response device 23 has a negative pressure chamber 23b and a lower chamber 23c defined by a diaphragm 23a, and a spring 23d inserted into the negative pressure chamber 23b presses the diaphragm 23a in the direction in which the exhaust recirculation valve 22 closes. are doing. The lower chamber 23c communicates with the atmosphere via an air passage 27, and the negative pressure chamber 23b communicates with the downstream side of the throttle valve 3 of the intake pipe 2 via a negative pressure passage 24 having a throttle.

An electromagnetic three-way valve 25 is provided in the middle of this negative pressure path 24, and when the solenoid 25a of the electromagnetic three-way valve 25 is energized, the valve body 25b opens the atmospheric path 2 equipped with a filter and a throttle.
6 is closed and the negative pressure path 24 is opened, so that the negative pressure on the downstream side of the throttle valve 3 of the intake pipe 2 flows into the negative pressure chamber 23b of the negative pressure response device 23. be introduced. As a result, the diaphragm 23a
Since there is a difference in pressure acting on both sides of the diaphragm 23a, the diaphragm 23a is displaced against the spring 23d, and the exhaust recirculation valve 22
Open the valve. That is, the solenoid 25 of the electromagnetic three-way valve 25
When a is energized, the exhaust gas recirculation valve 22 increases its opening degree to recirculate a portion of the exhaust gas to the intake pipe 2 via the exhaust gas recirculation path 21.

On the other hand, when the solenoid 25a of the electromagnetic three-way valve 25 is deenergized, the valve body 25b closes the opening 24a of the negative pressure path 24 and opens the opening 25c.

Atmospheric air is introduced into the negative pressure chamber 23b of the negative pressure response device 23.

At this time, the difference in pressure acting on both sides of the diaphragm 23a becomes approximately zero, and the diaphragm 23a is pressed and displaced by the spring 23d, moving the exhaust gas recirculation valve 22 in the direction of the valve closing force. That is, if the solenoid 25a of the electromagnetic three-way valve 25 continues to be deenergized, the exhaust gas recirculation valve 22 will be fully closed to cut off the recirculation of exhaust gas.

The solenoid 25a of the electromagnetic three-way valve 25 is the ENG-ECU5
electrically connected to. Symbol 28 is negative pressure response device 2
The diaphragm 23a is connected to the diaphragm 23a of No.3.
It is a valve lift sensor that detects the amount of deviation of a, that is, the actual valve opening of the exhaust recirculation valve 22, and the valve lift sensor 28 is also ENG.
-EC: electrically connected to tJ5.

The ENG-ECU 5 determines the engine operating state based on engine parameter signals etc. from the various sensors mentioned above.
The valve opening command value Lcno of the exhaust recirculation valve 22 is set according to the intake pipe absolute pressure PB^ and the engine speed Ne, and the actual valve opening value LACT of the exhaust recirculation valve 22 detected by the valve lift sensor 28. An on-off signal is supplied to the electromagnetic three-way valve 25 at a duty ratio of 5 according to the deviation so as to make the deviation zero.

The valve opening command value LCMD is set to gradually increase after the engine operating state changes from a region where exhaust gas recirculation is to be performed to a region where it is not to be performed.

In this embodiment, the ENG-ECIJ5 is a part of the excessive slip detection means, the fuel control means, the exhaust gas recirculation stop means, the memory means, the fuel amount determination means, the first and second lean means, and the fuel cutoff means. and constitutes an increase correction stop means, '
The rC3-ECU 30 constitutes a part of the excessive slip detection means.

ENG-ECU5 includes various sensors and Te3-ECU30
An input circuit 5a, a central processing circuit (hereinafter referred to as rcPU) 5b, and a CPU 5b, which have functions such as shaping the input signal waveform from the input signal, correcting the voltage level to a predetermined level, and converting analog signal values into digital signal values. Storage means 5 for storing various calculation programs and calculation results executed by
C1 Output circuit 5 that supplies a drive signal to the fuel injection valve 6
It consists of d, etc.

Based on the above-mentioned various engine parameter signals, the CPU 5b determines various engine operating states such as a feedback control operating range to the stoichiometric air-fuel ratio by the 02 sensor 15 and an open loop control operating range, and also determines the following according to the engine operating state. Based on formulas (1) and (2), the T
The fuel injection time `I''0II7 of the fuel injection valve 6 which is synchronized with the DC signal pulse and the fuel injection time TM^ for acceleration increase which is not synchronized with the DC signal pulse are calculated.

Touy=TiX KTC3X KwotX KO2X
KI+TAccXK2+ to 3-(1) Tr+^=゛"i^XKt^ten to 3^・
...(2) Here, Ti is the basic fuel amount, specifically the basic fuel injection time determined according to the engine speed Ne and the intake pipe absolute pressure PB^, and in order to determine this Ti value. As the Ti maps, a normal Ti map used in normal engine operating conditions and a traction control Ti map used during traction control (driving wheel slip control) to be described later are stored in the storage means 5c.

The Ti value of this Ti map for traction control is
It is set so that the stoichiometric air-fuel ratio can be obtained over the entire operating range of the engine when the engine is not operated (exhaust gas recirculation is not performed). This is because the normal 1゛i map is set to be richer than the stoichiometric air-fuel ratio on the high load side, so it is impossible to control the air-fuel ratio to a constant value simply by multiplying it by the lean coefficient. Therefore, in this embodiment, l
- The Ti value of the 1-i map for traction control is set so that the stoichiometric air-fuel ratio can be obtained in the entire operating range, and the lean coefficient (K rcs described later) is used to obtain an accurate air-fuel ratio.

It goes without saying that if the Ti map for traction control is originally set to obtain an air-fuel ratio on the lean side of the stoichiometric air-fuel ratio (for example, A/F = 18.0), the above-mentioned lean coefficient becomes unnecessary. stomach.

Further, Ti^ is a fuel increase reference value during acceleration that is not synchronized with the TDC signal pulse, and is stored in the storage means 5c as a map like 'I' i.

K Te3 is a lean correction coefficient that is set to a value smaller than 1.0 as described later when an excessive slip state of the driving wheels is detected, and is set to a value of 1 when the driving wheels are not in an excessive slip state. Set to .0.

KWOT is the correction coefficient for enriching the air-fuel mixture when the throttle valve is fully open; It is a variable.

Kl in formula (1), K2. K3 and equation (2) 1^
.

K3^ are other correction coefficients and correction variables that are respectively calculated according to various engine parameter signals, and are predetermined values that allow optimization of engine characteristics such as fuel consumption characteristics and engine acceleration characteristics according to engine operating conditions. determined.

The CPU 5b further determines the ignition timing era according to the engine speed Ne and the intake pipe absolute pressure PB^.

And it performs on/off control of the electromagnetic three-way valve 25 of the exhaust gas recirculation mechanism 20 according to the engine operating state.

Based on the results calculated and determined as described above, the CI) U 5 b outputs a signal for driving the fuel injection valve 6, the spark plug 16, and the electromagnetic three-way valve 25 via the output circuit 5d.

FIG. 2 is a block configuration diagram showing the internal configuration of the 'rC3-ECtJ30, in which the detection signals of the left and right driven wheel speed sensors 33 and 34 are sent to the first subtraction circuit 41 and the first average value calculation, respectively. It is input to circuit 46. The first subtraction circuit 41 calculates a speed difference ΔV r (=WtL−WRR) between the left and right driven wheel speeds WRL and Wtg, and supplies the calculated speed difference ΔV r (=WtL−WRR) to the first multiplication circuit 42 . The first multiplication circuit 42 calculates the tread width d of the left and right driven wheels (for example, d=
1, 2rn), an approximation 1[Y'n (=ΔVrXd) of the yaw ray 1- is calculated and input to the first storage circuit 43 and the filter circuit 44. The first storage circuit 43 stores the approximate value Y'n of the yaw rate, and
) η equivalent value Y'n-i is input to the filter circuit 44. Here, since the filtering operation is repeated in a constant cycle, the subscripts n and n-1 represent the current value and the previous value in that cycle.

The filter circuit 44 obtains the yaw rate Yn by filtering the approximate value Y'n of the yaw rate, and a second storage circuit 45 is connected to its output side. The second storage circuit 45 stores the output Yn of the filter circuit 44, and stores the output Yn of the filter circuit 44 nij times ftetYn-t.

It is input to the filter circuit 44 as the value Y11-2 from the previous time. The filter circuit 44 receives the above-mentioned input signal 75 ports.

Y'n-+, Yn-+, Yn-z are applied to the following equation (3) to calculate yaw 1-Yn, and the second subtraction circuit 5
Supply to 1.

Yn=atXY'n+αzXY'n-++βIXY11
-1+β2XYlow2 ・°・ (3) Here, β1
．． β2. β1. β2 is a constant determined by experimental results.

This filter circuit 44 is a recursive low-pass filter, and is used to remove the influence of the left and right driven wheel speeds WRL and WRR/\ due to vibrations of the vehicle suspension.

For example, the left and right driven wheel speeds We+, WRI! due to vibration and resonance of the suspension while driving on rough roads. The fluctuation frequency of is about 1,01-1 Hz, whereas the frequency range of the yaw rate used to control vehicle motion is about 0 to 2 Hz, so the filter circuit 44 has a frequency range of 3 fl z or more.
The approximation of the yaw rate 11αY' is filtered using the second attenuation region. The yaw rate Yn is a value determined by Jiffing the actual yaw rate centered on the center of gravity axis of the small circle, and outputs a positive value when turning to the right, and a negative value when turning to the left.

The first average direct calculation circuit 46 calculates the average value Vv (= (WI!L) of the left and right driven wheel speeds WRL and WRR.
+WRi)/2) is calculated as the vehicle speed, and the calculated value is sent to the calculation parameter selection circuit 47 and the standard deviation (D
s) Calculation circuit 54 and base fli1 driving wheel speed (Vre'
) calculation circuit 57. The calculation parameter selection circuit 47 has a reference yaw rate (
Y bn ) calculation parameters as, a2 . Set the values of bt and b2 to 0? j is selected according to the vehicle body speed Vv, and the selected value is input to the reference yaw rate calculation circuit 48.

On the other hand, the output side of the steering sensor 35 is connected to a third storage circuit 49, and the third storage circuit 49 stores the detected steering angle δ and calculates the steering angle cl) niJ equivalent an−+ , 1iiJ each time value δn-2 is manually input to the calculation circuit 48. A fourth storage circuit 50 is connected to the output side of the reference yaw rate calculation circuit 48, and the fourth storage circuit stores the calculated reference yaw rate 14.
bn is stored, and the stored value is the previous value Ybn-+.

1); 1it 14 times! It enters the reference yaw rate calculation circuit 48 as Ybn-2. The base fl11 yaw rate calculation circuit 48 calculates the history of changes in the steering angle δ (δn-1.δll-
2) and the change history of the reference yaw rate Yb itself (Ybn-
1, Ybn-2), the current reference yaw rate Ybn is calculated using the physical model equation (4), and is input to the second subtraction circuit 51 and the steering characteristic determining circuit 52.

Ybn= a tXδn-t+atxδ1l-2-bl
XYbn-t-b 2

0; 1 The second subtraction circuit 51 calculates the deviation 1)r (= Yn - Ybn) between the yaw rate Yn calculated by the equation (3) and the reference yaw rate Ybn, and determines the steering characteristic. The signal is input to a circuit 52 and an absolute value converting circuit 53. The absolute value conversion circuit 53 converts the absolute value of the deviation Dr to 1.
Drl is input to the third subtraction circuit 55. The steering characteristic determining circuit 52 determines the steering characteristic as follows based on the reference yaw rate Yb and the deviation Dr, and supplies the result to the standard deviation (DS) calculating circuit 54.

(1) When Ybn)O, Dr)0 or Ybn(
0°Dr (when it is O, it is determined that there is oversteering.

(2) When Ybn<O, Dr>0, or Ybn)
O.

When Dr(O), it is determined that understeering is occurring.

The vehicle body speed Vv and the steering angle δ detected by the steering sensor 35 are inputted to the Ds calculation circuit 54 together with the steering characteristic determination result, and the Ds calculation circuit 54 calculates the steering characteristic based on these input signals. Deviation Ds
is calculated and input to the third subtraction circuit 55. This standard deviation Ds is a standard value of the yaw rate deviation Dr calculated based on the vehicle speed Vv, the steering angle δ, and the steering characteristics, and increases as the vehicle speed Vv decreases and the steering angle δ increases. Set. This is because when the driven wheel speed, that is, the vehicle body speed is low and the steering angle δ is large, the steering characteristics of the vehicle become nonlinear, whereas the reference yaw rate Yb calculated by the reference yaw rate calculation circuit 48 is
This is because since n is linear, the deviation Dr between the reference yaw rate Ybn and the yaw rate 7 becomes large. Also,
In the case of a front-wheel drive vehicle, applying excessive driving force while turning the steering wheel tends to cause understeering, so when the determination result of the steering characteristic determining circuit 52 indicates understeering, the standard deviation Ds is made small. This means that the absolute value of yaw rate deviation 1
This increases the Drl deviation B (=lDrDs) and ultimately acts in the direction of lowering the engine output. As a result, the above-mentioned understeering tendency can be prevented.

On the other hand, in the case of a rear-wheel drive vehicle, when excessive driving force is applied, there is a tendency for oversteering, so contrary to the case of the NiJ wheel drive vehicle described above, the engine output is reduced when an oversteering condition is detected. The standard deviation Ds is changed in the direction of decreasing it.

The third subtraction circuit 55 calculates a deviation B (=lDr 1 - Ds) of the yaw rate deviation absolute value IDr 1 and inputs it to the second multiplication circuit 56 . Second multiplication circuit 56
is a correction term KXI for correcting the reference driving wheel speed V rer to be described later by multiplying the deviation B by a predetermined constant K.
3 is calculated and supplied to the fourth subtraction circuit 58.

A reference driving wheel speed Vref calculating circuit 57, into which the average value of the driven wheel speed calculated by the first average value calculating circuit 46, that is, the vehicle body speed Vv, is inputted, calculates the standard driving wheel speed according to the vehicle body speed Vv. As the speed (Vrof), a target value VRP of the drive wheel speed, a first predetermined drive wheel speed VRI, and a second predetermined drive wheel speed VR2 are calculated and input to the fourth subtraction circuit 58. A fourth subtraction circuit 58 calculates the correction term KX from the three reference driving wheel speeds VRI, VR2 and Vgr.
[Subtract 3 to get the corrected reference driving wheel speed V'*t (
=V*t-KXB).

V'u (=VR2-KX B) and V'RP (=V
1) U1°
It is input to the Y calculation circuit 60.

On the other hand, the detection signals of the left and right drive wheel speed sensors 3] and 32 are input to a second average value calculation circuit 59, and the second average value calculation circuit calculates the average value Vw (=( W
pt+Wpi)/2) is calculated and input to the DtJTY calculation circuit 60.

The three reference driving wheel speeds jffiV*t, VR2 and VRP are, for example, as shown in FIG. 3, the vehicle body speed Vv,
Straight line A showing the relationship between the vehicle body speed Vv and the driving wheel speed Vw
, B, and C. In general, the slip ratio λ, which represents the degree of drive wheel slip, is λ= (Vw−Vv
)/Vw...(5), but as this slip rate λ increases, 1. Tires, road surface and 11! The driving force due to the frictional force in the longitudinal direction (that is, in the traveling direction of the vehicle) is determined by the second slip ratio λ2 (for example, 15
%), and decreases when the slip rate λ exceeds λ2. Further, the critical lateral force between the tire and the road surface decreases as the slip ratio λ increases, as shown by the broken line in the figure. Therefore,
When the slip ratio λ exceeds the second slip ratio λ2, the driving force in both the longitudinal direction and the lateral direction decreases, and a sufficient driving force or limit lateral force cannot be obtained. - force, slip ratio λ is the first
When the slip ratio is smaller than ^l (for example, 5%), the drive wheel slip does not exceed the limit and stable grip is obtained.

Considering the above points, the straight lines A and B in FIG. 3 correspond to the first and second slip ratios λ1. in FIG. Make it correspond to λ2,
When the relationship between the detected driving wheel speed Vw and the vehicle body speed Vv is within the region between straight lines A and B, the increasing tendency of the driving force is in the linear region with respect to the increase in the slip ratio, so the slip ratio λ= Drive wheel speed VRP at λ0 (e.g. 8%)
(corresponding to straight line C in FIG. 3) is set as the target value of the driving wheel speed, and driving wheel slip control is performed according to the slip value opening TY, which will be described later. However, the standard driving wheel speed actually used to calculate the DUTY value is the corrected standard driving wheel speed V'l! corrected by the fourth subtraction circuit! 1. V'! and V'RP
It is.

The DUTY calculation circuit 60 calculates the detected driving wheel speed Vw.
By applying the corrected standard driving wheel speeds V'tt, V'gt and V'+r to the following equations (6) to (10), the slip value D is determined as a parameter according to the degree of driving wheel slip.
Calculate UTY, and use the calculation result as the surrounding TY signal.
G-E CU 5 is supplied.

DtJ1'Y=(V!!rn-VR+n)/(Vg
zn-VRIll)-Dn... (6) Dn=Dn-1+ΔDn-(7
)ΔDn=KpX ΔVwr++X(Vgrn−Vw
n)+KoX(ΔVwn−ΔVwn−+)
−(8)ΔVwn=Vwn−Vwn−+
−(0)ΔVWP= (Vwn
-t-VRrn-+) -(Vwn-V*rn)
-.-(10) Here, KP, Kl, and KO are predetermined proportional gains, integral gains, and differential gains, respectively. Furthermore, since the calculation is repeated in a constant cycle, the subscript [1°f)-1 represents the current value and previous value in that cycle.

Using the above formulas (6) to (10), the slip value DU'rY
By calculating the detected driving wheel speed Vw, the so-called tracking type PID control is applied to the driving wheel slip control.
It is possible to reduce the influence of noise components (error elements) included in the noise component and perform appropriate driving wheel slip control. Note that the slip value DU'rY increases as the slip rate λ of the driving wheels increases.

As mentioned above, the slip value opening TY is based on the reference driving wheel speed Vgt, which is calculated according to the vehicle body speed Vv, and VR2゜■k.
P, steering characteristics (degree of oversteering or understeering), steering angle δ, and vehicle speed V
This slip value DUTY is calculated based on the reference drive wheel speed V'R1, V'R2°V'RF obtained by correction by the correction term KXB according to v and the detected drive wheel speed Vw. By controlling the engine output using the above, it becomes possible to appropriately control the drive wheel slip and the yaw motion of the vehicle over a wide range of vehicle speed and steering angle.

FIG. 5 shows engine output control (hereinafter referred to as [traction control g9J ) is a flowchart of a program that executes. This program is executed in synchronization with each generation of the I'' DC signal pulse. This program assumes that the engine l is a 6-cylinder engine.

First, it is determined whether the engine rotation is in a high speed mode or a medium speed mode according to the engine rotation speed Ne (step 501), and if the answer is negative (NO), that is, it is in a low speed mode, the process immediately proceeds to step 505. If the answer is YES, that is, the medium-high speed mode is selected, it is further determined whether the medium-speed mode is selected (step 502). When the answer to step 502 is affirmative (Yes), that is, in the medium speed mode, it is determined whether the cylinder to which fuel is to be injected during the current execution of this program (hereinafter referred to as the "current cylinder") is the #2 cylinder or the #6 cylinder. It is determined (step 503). Step 5
When the answer to 02 or 503 is negative (No), that is, in high speed mode or medium speed mode, the current cylinder is #2.
If it is not #6, it is determined whether the current cylinder is #6 (step 504). If the current cylinder is not #6 in the medium speed mode or in the high speed mode, step 50
If the answer to step 4 is negative (NO), this program is terminated without executing the calculations from step 505 onwards, and fuel injection (or twin cut) and ignition are performed based on the latest calculation results calculated up to the previous time. Step 503 or 504
If the answer is affirmative (Yes), that is, if the current cylinder is #2 or #6 in the medium speed mode, or if the current cylinder is #6 in the high speed mode, the process advances to step 505.

In step 505, the zero slip value DUTY is read and the TC condition determination subroutine shown in FIG. 6 is executed to determine whether the conditions for performing traction control (hereinafter referred to as TC condition J) are satisfied. (step 506).

In step 601 of FIG. 6, it is determined whether the DUTY signal is abnormal or not, that is, the upper and lower limits of the slip value DUTY are checked. If the answer is negative (No), that is, the TY signal is normal, the battery voltage V IIAD is the predetermined voltage VeτC
Determine whether the voltage is below L (for example, 10V) (step 6
02). If the answer to step 602 is negative (NO), that is, VB
When AD>VBTCL holds true, engine coolant temperature T
It is determined whether w is equal to or higher than a predetermined upper limit water temperature T'wrco (for example, 99° C.) (step 603). Step 60
If the answer to No. 3 is negative (No), that is, Tw (Twrcu) is established, it is further determined whether or not the engine water temperature T's is below a predetermined lower limit water temperature "I'WTCL (for example, -29°C)" (step 604). If this answer is negative (No), that is, l'w)TwycL holds, then the intake temperature 'r^
is the predetermined upper limit intake temperature 'FATCI+ (e.g. 69℃)
It is determined whether or not this is the case (step 605). If the answer to any of the above steps 601 to 605 is affirmative (Yes), that is, the DIJTY signal is abnormal or V BAD≦
VIITCL, TW≧'"wrc++,Tw≦i'
When either WTC + or ■゛^≧'1゛^TCI+ is established, traction control should be performed.
It is determined that the 'rC condition is not satisfied, that is, the 'rC condition flag FTCEN13L is set to 0 (step 607), and this routine is ended. This is achieved by performing traction control by making the air-fuel ratio of the air-fuel mixture supplied to the engine lean or by cutting the air-fuel mixture to the engine.■I) UT
Appropriate control cannot be performed when the Y signal is abnormal; ■When the battery voltage VB^0 is low (VBAD≦VBTCL), it is not guaranteed whether the DUTY signal indicates a slip condition; ■The engine temperature is high (Tw≧' l
``wrcu, 'l'^≧T^dingC11) Sometimes,
The engine cooling effect from supplying fuel is lost,
This is because there is a risk of causing unexpected damage to the engine, and (2) when the engine temperature is low (Tw≦Twrct), there is a risk of misfire.

On the other hand, the answers to steps 601 to 605 are all negative (N
o), that is, the TY signal is normal and VBAD>
When VBTCL, TWTCII>TW>TWTCL, and TA<TATCI+ are all satisfied, it is determined that the TC condition is satisfied and the TC condition flag FTCIENI3 is set.
1 is set to 11111 (step 606), and this routine ends.

Returning to FIG. 5, in step 507, the throttle valve opening is turned on.
+ is less than a predetermined opening degree of 0pc (for example, 1.5°), and if the answer is affirmative (Yes), that is, the throttle valve is almost completely idle, it is determined that there is no need to perform traction control. , to set the actual traction control level (hereinafter referred to as "actual TC level") to LVLN.
The process proceeds to step 523 (FIG. 5C) and step 546 (FIG. 5C). If the answer to step 507 is negative (NO),
In other words, when On+)θ'C holds true, the engine speed Ne becomes the predetermined speed N1'ClNl1 (for example, 1.50
Orpm) or less is determined (step 508).

The answer to step 508 is affirmative (Yes), that is, No≦NT
When CIN11 is established, it is determined that traction control should not be performed because there is a risk of engine stalling if traction control is performed, and the process proceeds to step 539 (FIG. 5(b)), which will be described later. On the other hand, if the answer to step 508 is negative (No), that is, N e )NTCIN
When II holds, the first callan %CTCNEL
is set to the value 0 (step 509).

This first counter CTCNEL changes from negative (NO) to positive (Yes) in step 508, that is, N.

) This is for gradually lowering the traction control level, which will be described later, when Ne≦NTCINI+ changes from NTCINII.

Next, the detected engine speed N? and intake pipe absolute pressure P
Based on s^, it is determined in which region of Z (INE 1 to 4) the engine operating state is, for example, set as shown in FIG. 7 (step 510).

ZONE and slip value opening T determined in step 510
The traction control level (rTC
A table for determining the instruction level (hereinafter referred to as "instruction TC level") CMDLVL (hereinafter referred to as "instruction TC level") is set as shown in FIG. 8, for example. According to the table in FIG. 8, the command TC level CMDLVL is determined as follows.

1) TCFCLVLMIN≦DUTY value (TCFC
LVL O node ICMDLVL = LVLN 2) TCFCLVL i≦DUTY value<TCI? C
LVL (i + t) (7) when CMDLVL=LVL
i (just, i=0~5)3) TCFCLV
L 6 ≦ DUTY value < TCFCLVLMAX (7)
ICMDLVL = LVL 6 However, DUTY value (TCFCLVLMIN or DUT
When Y value≧TCFCLVLM^x, in step 506 (7) TC condition determination subroutine, I)
T'/signal is determined to be abnormal, flag FTCE
N13L is set to the value O.

Furthermore, as is clear from FIG. 8, the predetermined threshold value TCF
CLVL_L takes different values depending on the ZONE (however, in the illustrated example, TCFCLVL_O is constant regardless of the ZONE). This is because even if the slip value (DtJTY) is the same, that is, the driving wheel slip state is the same, the TC level needs to be varied depending on the operating state of the engine. In other words, in the operating range where the original engine output is low, the increase in the slip state of the drive wheels will not suddenly become excessive, so drivability will be improved by gentle control, but conversely, the engine output will increase. In a large range, there is a high possibility that the excessive torque applied to the drive wheels will be large, and in such a state, the change in the increasing side of the slip ratio λ will be rapid, so it is necessary to ensure more rapid controllability. Ru. Therefore, in this embodiment, ZO is adjusted depending on the intake pipe absolute pressure Pa^ and the engine speed Ne.
Predetermined threshold value TCFCLVL O~TCFCL for each NE
By setting VL6, it is possible to perform control such that when the engine output is high, the number of cylinders that undergo twin cylinder cut is increased earlier than when the engine output is low.

FIG. 9 is a table for determining the content of traction control according to the 'rC level, and the table in the figure is for equalizing the air-fuel ratio of the air-fuel mixture supplied to the engine;
/C indicates that a twin cut is performed. Furthermore, the cylinder correspondence number M on the horizontal axis indicates that after the start of traction control, the cylinder to which fuel is first injected is the cylinder corresponding to M=1, and the cylinders to which fuel is injected sequentially thereafter are the cylinders corresponding to cylinder correspondence number M=
2 to 6, respectively. For example, TC level = LVLO
When , the air-fuel ratio of the mixture supplied to all cylinders is lean, and TCL/Bel = LVI, 3 (7) when M
The cylinder corresponding to M = 1°3.5 is subjected to a twin unit cut, and the other cylinders (cylinders corresponding to M = 2.4.6) are subjected to a lean air-fuel ratio.

Note that LVI and N in FIG. 8 indicate that traction control is not performed, that is, normal fuel supply and ignition timing control are performed.

Returning to FIG. 5(a), in step 511, step 5
The above threshold value TCF is set according to the ZONE determined in step 10.
CLVL i (7) Select the value and select the selected TCFC
Based on the LVL i (7) value and the slip value DUTY, the instruction 'rC level CMDLVL (hereinafter simply rCMD
LVLj,! ti (step 512)
. Next, the process proceeds to step 514 in FIG. 5(b), where it is determined whether the 'C condition flag I'TCEN [31,
If the condition is satisfied, it is determined whether the TC condition flag FTCENI3L was equal to the value l last time (when this program was executed last time) (step 515). When the answer to step 514 is affirmative (Y e s ) and the answer to step 515 is negative (No), that is, when the 'rC condition has not been satisfied 111 times and is satisfied this time, the condition is set as described below. Rumi 'I' C level ^CTLVL
(Hereinafter written in single 4.: rAcTLVl,,J) is L
It is determined whether it is VLN (step 516).

When the answer to step 515 or 516 is 11 (Yes), that is, when the TC condition is satisfied n11 times, or when ACTL
When VL is LVLN (7), CMDLVL is LVL
Nt? It is determined whether there is any space or not (step 518). If this answer is affirmative (Yes), that is, CMI], VL is LVLN
, and when traction control is not required, A
Set CTLVL to LVLN (step 523),
Proceed to step 546 (FIG. 5(C)). On the other hand, if the answer to step 518 is negative (NO), LVL (CMI) is L.
When VLN is not present, ACTLVI is set to LVLO and the second counter CT (:[3L is set to value O).
(step 519), the process proceeds to step 520, where it is determined whether the value of the second counter CTCI3L is greater than or equal to a second predetermined count value Bl (for example, 40). In this case, the answer is naturally negative (No), and in step 522, the second counter CTC[3L is incremented by the value l, and the process proceeds to step 531. Set to the value 0.

On the other hand, the answer to step 516 is negative (No), that is, A
When CTLVL is not LVLN, IL, CMDLVL
Determine whether or not there is an LVLN (step 517).
. If the answer is negative (No), that is, traction control is required, the process proceeds to step 520. If the answer to step 520 is negative (No), step 5
If the result is affirmative (Yes), ACTLVL is set to CMDLVL, and the process proceeds to step 531.

The control in steps 515 to 523 described above is control at the start of traction control and while the traction control is continuing, and according to this control, CMDLVL and ^CTLVL! ;E For example, as shown in FIG. 10(a). In the figure, the horizontal axis is the number of TDC signal pulses (that is, the axis corresponding to the time axis), and at time t1, the driving wheels enter an excessive slip state, and the slip value I)U
This shows a case where TY suddenly increases and CMDLVL immediately changes from LVLN to LVL 3.

In this case, AC1'LVL has TDC signal pulse Ij
:I is held at LVLO while the second predetermined count value nBT= is generated (from time t, l to 2), and thereafter controlled to be equal to CMDLVL. As a result, even if the drive wheel slip suddenly becomes excessive, the air-fuel mixture supplied to all cylinders will always go through LVLO control, which leans the air-fuel ratio of the air-fuel mixture.
Since a twin cut is performed according to the slip condition (in the illustrated example, three cylinders are cut by shifting to LVL3 control), the residual fuel adhering to the inner wall of the intake pipe is sucked into each cylinder during the LVL O control. Even if three cylinders are cut when shifting to LVL 3 control, deterioration of exhaust gas characteristics and performance deterioration of the exhaust purification device can be prevented.

If the answer to step 516 is negative (NO), that is, ACTL
When VL is not LVLN and the answer to step 5 is affirmative (Yes), that is, CMDLVL is LVLN,
In other words, when the state changes from a state requiring traction control to a state not requiring traction control, after-traction control is performed in steps 524 to 531 below.

First, it is determined whether the after TC flag FAL is equal to the value 1 (step 524), and the answer is affirmative (Y
es), the process immediately proceeds to step 526, and when the answer is negative (NO), the third counter CTCOFF is set.
is set to the value 0 and the after 'rc flag FAL is set to the value 1 (step 525).
Proceed to step 26. In step 526, AC1'LVL is set to L.
Determine whether it is VL O or not, and the answer is negative (NO)
In this case, it is determined whether the value of the third counter CTCOFF is greater than or equal to a third predetermined count value nTc0FF (for example, 20) (step 529). When the answer to step 529 is negative (No), that is, when CTCQFF (nTcOFF) is established, the third counter CTCOFF is incremented by the value l (step 530), and step 5
46 (FIG. 5(C)). On the other hand, the answer to step 529 is affirmative (Yes), that is, CTCOFF≧nTc0FF
is established, the process advances to step 528 and ACTL
VL is lowered (for example, when ACTLVL is LVL3, it is set to LVL 2), and 1) Proceed to step 531 in iJ. Also, the answer to step 526 is affirmative (Y
es), that is, when ACTLVL is LVI, O,
The value of the third counter CTCOFF is the fourth. It is determined whether or not the predetermined count value nTc0FF O (for example, 40) or more is reached (step 527). When this answer is negative (No), that is, CTCOFF(nTcOFFO holds),
Proceeding to step 530, the answer is determined (Yes);
That is, when CTCOFF≧ncTcOFFO holds true, the process proceeds to step 528.

According to the aftertraction control in steps 524 to 531 described above, AC'
rLVL is controlled, for example, as shown in FIG. 10(b). FIG. 10(b) shows that at time L1, the excessive slip state of the driving wheels is resolved and CMDl and VL are LVL 3.
LVLN is shown. in this case,
CMDLVL transitions to LVLN and also ACTLVL4J
Immediately! :Do not follow CMDLVL, ACTLVL is L
Until reaching VLO, the TDC signal pulse is lowered by a level each time a third predetermined count value nTc0FF is generated, and when ACTLVL is in the state of LVLO, the TDC signal pulse reaches the fourth predetermined count value TCO['F O ACTLVL is held until LVLN is generated, and ACTLVL is finally set to LVLN to complete the traction control. This after-traction control prevents a sudden increase in engine output immediately after the excessive slip condition of the drive wheels is resolved.
Drivability can be improved.

If the answer to step 514 is negative (NO), that is, the TC condition is not satisfied, it is determined whether the previous TC flag FTCENBL was equal to the value l (step 532).
, if the answer is affirmative (Yes), that is, the previous TC condition was satisfied, it is determined whether ACTLVL is LVLN (step 534). If the answer to step 534 is affirmative (Yes), proceed to step 523,
If negative (No), repeat 8CTLVL two times before (7)
Set ACTLVL tare 6A (: Tl, VLS (8 CTLVL at the time of the occurrence of the TDC signal pulse two times before) and set the fourth counter CTCIN11 to the value O (step 535), proceed to step 536, and in step 536 the fourth counter It is determined whether or not the value between the counters CTC1 is greater than or equal to a fifth predetermined count value INI+ (for example, 30), but when the value has passed through step 535,
The answer is negative (NO), and the fourth counter CTCINI+ is incremented by the value l in step 538, and the process proceeds to step 546 (FIG. 5(C)).

If the answer to step 532 is negative (No), that is, the previous TC
When the condition is not met, ACTLVL becomes LVLN
It is determined whether or not (step 533). If this answer is affirmative (Yes), proceed to step 523,
If the answer is negative (No), the process proceeds to step 536. If the answer to step 536 is negative (No), that is, CTC1 <
When n1Ntl is established, 0; Step 53
8, if the answer to step 536 is affirmative (Yes), that is, C1°CINII≧n1NII, then A
CTLVL is lowered and the fourth counter CTCIN11 is set to the value O (step 537).
, proceed to step 546 (FIG. 5(C)).

Steps 532 to 538 described above are for performing control when the 1C condition is not satisfied, and are intended to prevent a sudden increase in engine output, especially when the TC condition is not satisfied during traction control. It is. According to this control, as shown in FIG. 10(c), for example, even when the slip value opening TY becomes an abnormal value at time L1, the TC condition is not satisfied, and CMDLVL suddenly increases, A
CTLVL is 2TD from time j1 (JfJ (previous episode)
(7) ACTI is held at VL (TEHA LvL2 in the illustrated example) and 'I' D is held by the fifth predetermined count value n1NII.
Each time a C signal pulse is generated, the level is lowered by one level, and finally reaches LVLN and traction control ends.

Thereby, even if the TC condition is not satisfied during traction control, a sudden increase in engine output can be prevented and drivability can be improved.

The answer to step 508 is affirmative (Yes), that is, the engine speed Ne is low and Ne≦NTCINII holds true6.
Toki G: CMDLVL is set to LVLN (step 539), and it is determined whether ACTLVL is LVLN (step 540). This answer is affirmative (Yes
), immediately proceed to step 546 (FIG. 5(C)).
When the result is negative (No), ACTLVL becomes LVL.
It is determined whether or not O (step 541). If the answer to step 541 is negative (No), ACTLV
Set L to LVLO and proceed to step 546 (Figure 4).
Proceed to C)) and the answer to step 541 is 17 (Yes).
When , the first counter CTCNIEL(7)
It is determined whether the value is greater than or equal to the first (seventh) predetermined count value n'rcNEL (for example, 30) (step 542).

If this answer is negative (No), that is, CTCNEL (nTCNE
When L holds true, the first counter CTCNIEL
Increment by the value 1 and proceed to step 5.
45, the answer to step 542 is affirmative (Yes), that is, C.
When TCN[EL≧n'rcNIEL holds,
With ACTLVL set to I and VLN, the process proceeds to step 546 (FIG. 5(C)).

The control in steps 539 to 545 described above is intended to prevent a sudden increase in engine output, especially when the engine rotation number Ne decreases during traction control and becomes less than a predetermined rotation number NTC [Nll]. It is.

According to this control, as shown in FIG. 10(d), for example, when Ne≦NTCI at time L1, CM
DLVIj, - Regardless, ACTLVL becomes LVLO and after the sono state is held for a period of TDC signal pulses occurring for a first predetermined count value nTCNEL, ACTLVL becomes LVLO.
LVL becomes LVLN and traction control ends. As a result, engine speed N during traction control
Even when e decreases to below the predetermined rotational speed N'rCINII, a sudden increase in engine output is prevented and drivability is improved.

The above description of steps 514 to 545 applies when the engine speed is in the low speed mode, that is, when the steps from step 505 onwards are executed every time the i pulse is generated. In fast mode there are 3 1゛DC signal pulses, in high speed mode there are 6 ゛rDC signal pulses.
Each time the step 505 and the following steps occur, the steps starting from step 505 are executed simultaneously, so for example, the time 1 in FIG.
The number of TDC signal pulses generated during 2 is 3XnBL in medium speed mode.

In the high speed mode, it becomes Q X n B L. Same figure (b)
.

nTc0FF, nTc0FFo, n in (c)
The same applies to TNll. Also, the day before last (2TD
CllJ)'s AC: TLVLtea6ACTLVLS41
, before GTDC in medium speed mode, 12T in high speed mode
Before Dc (7) becomes ACTLVL.

In step 546 of FIG. 5(c), it is determined whether AC'rLVL is LVLN, and the answer is negative (No).
, Immediately ACTLVL is LVL O ~ LVL 6 (7)
When the traction control is being performed in either of the above cases, the process proceeds to step 547, and the correction amount of the ignition timing Oxa applied when performing the air-fuel ratio lean control is adjusted according to the engine speed Ne, as shown in FIG. 11, for example. Search from the configured table. This is to prevent dielectric breakdown and knocking in the ignition system, which tend to occur due to leaner air-fuel ratios. That is, the engine speed Ne is 1
．． In the region of 500 rpm
In the pm range, the ignition timing is corrected to the retarded side to prevent knocking.

Next, the ignition timing θ10 is calculated based on the correction amount searched in step 547, the engine speed Ne, and the intake pipe absolute pressure 1"DA (step 548), and further based on the engine speed Ne and the intake pipe absolute pressure PII^. The basic fuel injection time Ti is determined by searching the Ti map for traction control (step 549).Next, ++10T is set to the value 1. to the enrichment correction coefficient when the throttle valve is fully opened.
0 (step 550) to stop the high load increase, and set the accelerated increase variable to @0 to stop the accelerated increase (
Step 551). Furthermore, the 02 feedback correction coefficient KO2 based on the output signal of the 02 sensor 12 is set to a value of 1.0, and the feedback control is stopped (step 55).
2). In step 553, in order to lean the air-fuel ratio of the air-fuel mixture, a lean correction coefficient 1 for drive wheel slip control is applied.
(Te3 is set to a lean predetermined value
Applying the correction coefficient and correction variable set in and the other correction coefficient and correction variable calculated separately to the above formula (1), T
A fuel injection time T2O synchronized with the DC signal pulse is calculated (step 554). Further, the fuel injection time TM^ for acceleration increase that is not synchronized with the TDC signal pulse is set to the value O to stop so-called asynchronous acceleration increase (step 555), and exhaust gas recirculation by the exhaust gas recirculation mechanism 20 is stopped. (Step 556) This program ends. After completing this program, fuel injection (or fuel injection) and ignition are performed based on the actual 'rC level AC:TI, V1, fuel injection time 'I'OUT and ignition timing O+a calculated as described above.

In this way, exhaust recirculation is stopped during traction control,
The 1'i value is determined using the traction control 'I'i map, which is set so that a constant air-fuel ratio is obtained over the entire operating range of the engine when exhaust gas recirculation is stopped.
Since the synchronous acceleration increase by the acceleration increase variable T ACC and the asynchronous acceleration increase by the fuel injection time TM^ for asynchronous acceleration increase are stopped, the air-fuel ratio of the air-fuel mixture supplied to the engine can be appropriately controlled even during traction control. Therefore, deterioration of exhaust gas characteristics can be prevented.

On the other hand, when the answer to step 546 is affirmative (Yes), that is, ACTLV+ is LVLN and traction control is not performed, normal control is performed. That is, the ignition timing θta is calculated (step 557), the basic fuel injection time Ti is determined by searching the normal 1゛i map (step 558), and the lean correction coefficient K rc is determined.
Step 5
60), exit this program. Incidentally, during normal control, the asynchronous acceleration increase by the above-mentioned -I''n^ is performed as necessary.

(Effects of the Invention) As detailed above, the present invention provides a driving wheel speed sensor that detects the driving wheel speed of a vehicle, and a driving wheel speed sensor that detects the driving wheel speed when excessive slip of the driving wheels is detected based on the output of the driving wheel speed sensor. Drive wheel slip control device comprising: excessive slip detection means for outputting a slip value according to the degree of slip; and fuel control means for controlling the amount of fuel supplied to an engine equipped with an exhaust gas recirculation mechanism according to the slip value. , an exhaust recirculation stopping means for stopping exhaust recirculation by the exhaust recirculation mechanism when the slip value is larger than a first predetermined slip value, and a substantially constant air-fuel ratio over the entire operating range of the engine. a storage means that stores a set basic fuel amount for driving wheel slip control; a fuel amount determining means that determines the amount of fuel to be supplied; and a first leaner that leans the air-fuel ratio of the air-fuel mixture supplied to all cylinders when the slip value is larger than the first predetermined slip value. , fuel cutoff means for cutting off fuel supplied to the number of cylinders corresponding to the slip value when the slip value exceeds a second predetermined slip value that is larger than the first predetermined slip value; A second leaner means for making the air-fuel ratio of the air-fuel mixture supplied to the cylinder other than the cylinder whose fuel supply is cut off by the fuel cutoff means when the second predetermined slip value is exceeded.゜, it eliminates the shock caused by a sudden drop in engine output when the drive wheels are in an excessive slip state, further reduces the door dynamic component of engine torque, and also reduces the deterioration of exhaust gas characteristics due to residual fuel in the intake pipe. This not only prevents performance deterioration of the exhaust purification device, but also allows the air-fuel ratio of the air-fuel mixture supplied to the engine to be appropriately controlled even when the drive wheels are in an excessive slip state, resulting in good exhaust gas characteristics. play.

Furthermore, since the increase correction stop means is provided for stopping the increase correction of the fuel supply amount performed during engine acceleration and high load operation when the slip value is larger than the first predetermined slip value in the AiJ slip slip value, In particular, the air-fuel ratio can be appropriately controlled even during sudden acceleration or high-load operation.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of a drive wheel slip control device according to an embodiment of the present invention, Fig. 2 is a block diagram of an electronic control unit for detecting drive wheel slip, and Fig. 3 corresponds to the slip rate of the drive wheels. Figure 4 is a diagram showing the relationship between the drive wheel slip rate and driving force; Figure 5 is a flowchart of a program for executing drive wheel slip control; The figure shows the conditions (1") for whether or not to perform traction control that reduces engine output.
Fig. 7 is a flowchart of a subroutine for determining the engine speed (ZONIE 1 to 4) according to the engine speed and the absolute pressure in the intake pipe, and Fig. 8 is a flowchart of the subroutine for determining the 1 to 4) and a table for determining the commanded traction control level according to the slip value, and FIG. 9 is a diagram showing a table for determining the commanded traction control level according to the traction control level. Figure 1 showing the table for
O diagram shows instruction I/traction control level (CMDLVL)
and the actual traction control level (ACTLVL) is TD.
FIG. 11 is a diagram illustrating how the ignition timing changes with the generation of the C signal pulse, and is a diagram illustrating an example of correcting the ignition timing during lean air-fuel ratio tli control. DESCRIPTION OF SYMBOLS 1... Internal combustion engine, 5... Electronic control unit for engine control (ENG-ECtJ), 6... Fuel injection valve, 20... Exhaust recirculation mechanism, 30... Electronic control for drive wheel slip detection Unit (Te3-E
CU), 31.32... Drive wheel speed sensor, 33°34... Driven wheel speed sensor, 35... Steering sensor. High 5 U (c)

Claims (1)

[Claims] 1. A driving wheel speed sensor that detects the driving wheel speed of a vehicle;
Excessive slip detection means for outputting a slip value corresponding to the degree of excessive slip when excessive slip of the driving wheels is detected in response to the output of the driving wheel speed sensor, and an exhaust gas recirculation mechanism according to the slip value. and a fuel control means for controlling the amount of fuel supplied to the engine, wherein the exhaust recirculation stop is configured to stop exhaust recirculation by the exhaust recirculation mechanism when the slip value is larger than a first predetermined slip value. storage means for storing a basic fuel amount for driving wheel slip control set so as to obtain a substantially constant air-fuel ratio over the entire operating range of the engine;
fuel amount determining means for determining the amount of fuel to be supplied to the engine based on the basic fuel amount for driving wheel slip control when the slip value is larger than the first predetermined slip value; a first leaner that leans the air-fuel ratio of the air-fuel mixture supplied to all cylinders when the slip value is larger than a predetermined slip value; and a second predetermined slip value that is larger than the first predetermined slip value. a fuel cutoff means for cutting off fuel supplied to a number of cylinders corresponding to the slip value when the slip value exceeds the second predetermined slip value; and a fuel cutoff means for cutting off the fuel supply when the slip value exceeds the second predetermined slip value. 1. A drive wheel slip control device comprising: a second leaner leaner that leans the air-fuel ratio of the air-fuel mixture supplied to the cylinders other than the cylinders. 2. The engine is characterized in that an increase correction stopping means is provided for stopping the increase correction of the fuel supply amount performed during engine acceleration and high load operation when the slip value is larger than the first predetermined slip value. The drive wheel slip control device according to claim 1.