JPS63309745A - Controller for slip of driving wheel - Google Patents

Abstract

PURPOSE:To reduce the exhaust quantity of uncombusted fuel by controlling the air fuel ratio of the mixed gas to a proper valve by making the correction value of for the fuel quantity corresponding to the engine operation state ineffective, when the slip state lower than the excessive slip state of a driving wheel is detected. CONSTITUTION:A vehicle 1 is set, for example, into front wheel drive type, and speed sensors 21-24 are installed individually onto the right and left driving wheels 11 and 12 and the right and left trailing wheels 13 and 14. Each detection signal supplied from the speed sensors 21-24 is calculation-processed in an ECU 35, and a plurality of fuel injection valves 36 of an engine 31 are controlled according to the result, and the excessive slip state of each driving wheel 13, 14 is controlled. In this device, if the slip state lower than the excessive slip state of each drive wheel 13, 14 is detected, the correction valve for correcting the fuel quantity jetted from each fuel injection valve 36 according to the engine operation state is made ineffective.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a drive wheel slip control device for a vehicle, and particularly to a control device that performs appropriate slip +l+IIf'II when the drive wheels transition to an excessive slip state. Regarding equipment.

(Prior art and its problems) In general, when a vehicle starts or accelerates, the driving force of the drive wheels is the friction force between the tires and the road surface [friction coefficient between the tires and the road surface x the load on the drive wheels of the vehicle weight (vehicle load )], the drive wheels slip, and the slip rate ^ representing the degree of this slip is determined by the following equation (1), where Vw is the circumferential speed of the drive wheels and V is the speed of the vehicle.

λ= (Vw-V)/Vw...(1) Depending on this slip ratio λ, the frictional force between the tire and the road surface (that is, the limit value of the driving force of the driving wheels) changes as shown in Fig. 8, This frictional force becomes maximum at a predetermined value λ0. Furthermore, the frictional force between the tires and the road surface is the frictional force in the direction of vehicle travel (vertical direction), but the frictional force in the lateral direction (lateral force) has a slip ratio λ as shown by the dotted line in the figure. The larger the value, the lower the value.

Based on this point, we maximize the longitudinal frictional force between the tires and the road surface to maximize the vehicle's drive efficiency, and also minimize the decrease in the lateral frictional force between the tires and the road surface to reduce the lateral drift of the vehicle. A slip prevention device for preventing slippage is disclosed, for example, in Japanese Patent Publication No. 52-35837.

However, in this conventional device, controlling the wheel speed to prevent excessive slip of the driving wheels does not involve changing the driving torque of the engine by switching the ignition device on and off or switching the supply and cutoff of fuel to the engine. Therefore, as the combustion state of the engine changes rapidly at the time of switching, unburned fuel is discharged from #1, resulting in an after-effect combustion process in which the fuel is combusted in the Ur gas system. If a fire occurs and a three-way catalyst is installed in the FEJ as an exhaust purification device,
There was a problem in that the performance of the two-way catalyst deteriorated because the temperature of the two-way catalyst increased.

(Objective of the Invention) The present invention has been made in order to solve the problems of the prior art described in ``-'', and it solves the problem of afterfire occurring when the drive wheels shift to an excessive slip state and the problem of the three-way catalyst in the exhaust system. It is an object of the present invention to provide a drive wheel slip control device that can prevent performance deterioration of a three-way catalyst caused by a temperature drop.

(Means for Solving the Problems) In order to achieve the object described in L, the present invention provides a fuel supply means for supplying fuel to an engine, a fuel supply means for supplying fuel to an engine, and an excessive slip state for detecting an excessive slip state of drive wheels of a vehicle. A drive wheel comprising a slip detection means and means for stopping the fuel 121 supply for stopping the fuel t'1 supply from the fuel f':1 supply stage when the excessive slip detection means detects an excessive slip state. In the slip control device, a slip detection means detects a slip state fIB lower than the excessive slip state of the drive wheel, and a slip detection means detects a slip state lower than the excessive slip state; correction value setting means for setting a correction value for correcting the amount of fuel to be supplied; and correction value invalidation for invalidating the correction value by the correction value setting means in number 011 when the slip detection means detects a low slip state in number 111. It is equipped with means for converting.

Ru.

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

FIG. 1 shows a vehicle 1 equipped with a driving wheel slip control device according to the present invention. The vehicle 1 is, for example, a front wheel drive type, and the front wheels 11 and 12 are driving wheels driven by an internal combustion engine 31. , the rear wheels 13° and 14 are driven wheels. (As will be clear from the following description, the present invention can be applied to rear-wheel drive vehicles in exactly the same way.

) The drive wheels 11.12 and the driven wheels 13.14 are provided with drive wheel speed sensors 2], 22 and driven wheel speed sensors 23.2.
The driving wheel speed sensors 21 and 22 detect the left and right driving wheel speeds ωF+, ωFR, and the driven wheel speed sensors 23 and 24 detect the left and right driven wheel speeds ωRL and ωPP, respectively. and these detection signals are referred to as electronic control unit rEcUJ).
35.

In this embodiment, the ECU 35 constitutes excessive slip detection means, slip detection means, fuel supply stop means, correction value setting means, and correction value invalidation means.

As described later, the ECU 35 controls the left and right driving wheel speeds ωFL,
ωF+! Select one of the above and apply the formula (1)
Let the driving wheel speed Vw be the driving wheel speed ωFL or GJFI! The speed of the driven wheel on the same side as ωR or ω
? ．． Letting R be the vehicle speed V in the above equation (1), the following equation (2
) to find the slip rate ^.

Furthermore, F. CU35 is the amount of change in slip rate λ (differential value)
Seek people. In addition, in digital control, this amount of change ^ is substituted by the difference between each calculation processing cycle.

Further, the transmission [6] interposed between the engine 31 and the drive wheels II and +2 is equipped with a sensor (not shown), and a transmission signal from the sensor is input to the ECU 35. The ECU 35 controls the output of the engine 3I using a fuel supply control device, which will be described later, to control the driving wheels] 1.12
The slip state of the drive wheels 11 and 12 is controlled by controlling the torque of the drive wheels 11 and 12.

FIG. 2 is an overall configuration diagram of the fuel supply control device. The internal combustion engine 31 has, for example, six cylinders, and an intake pipe 32 is connected to the engine 31. A throttle body 33 is provided in the middle of the intake pipe 32, and a throttle valve 33' is provided inside. A throttle valve opening (OTl+) sensor 34 is connected to the throttle valve 33' to convert the valve opening of the throttle rr33' into an electrical signal and send it to the ECU 35.

A fuel injection valve 36 is provided for each cylinder between the engine 31 and the throttle body 33 in the intake pipe 32, slightly upstream of the intake valve (not shown) of each cylinder. The fuel injection valve 36 is connected to a fuel II pump (not shown) and is electrically connected to the ECIJ35, and the opening time of the fuel injection valve 36 is controlled by a signal from the [ζCU35].

On the other hand, the throttle body: 33 throttle J "3
The intake pipe absolute pressure (P
RA) A sensor 38 is provided, and the absolute pressure signal converted into an electrical signal by this absolute pressure sensor 38 is sent to the ECU 35.

The engine 31 body has an engine cooling water temperature sensor (r
A Tw sensor (referred to as a "Tw sensor") 39 is installed, and the Tw sensor 39 consists of a screwdriver, etc., and is inserted into the circumferential wall of the engine cylinder filled with cooling water, and transmits the detected water temperature signal to the ECU.
35. An engine rotation speed sensor (hereinafter referred to as rNe sensor) 40 is installed around the camshaft or crankshaft (not shown) of the engine. position, i.e. at the start of the intake stroke of each cylinder -
8 = Crank angular position signal pulse (
This TDC signal pulse is sent to the ECU 35.

A three-way catalyst 42 is disposed in the exhaust pipe 41 of the engine 31, and performs a purifying action on I C , C O , and N O x components in the exhaust gas. An 02 sensor 43 is installed on the first stream side of the exhaust pipe 41 from the three-way catalyst/I2.
3 detects the oxygen concentration in the exhaust gas and sends the 02 concentration signal to the ECU
35.

Furthermore, the ECU 35 includes the drive wheel speed sensor 21.

22, the driven wheel speed sensors 23, 24 and other parameter sensors '++44, such as the sensor that detects the gear ratio of the transmission J6, are connected, and these various sensors supply their detected value signals to the ECU 35. do.

The ECU 35 includes various sensors (the drive wheel speed sensor 21,
22, nij driven wheel speed sensor 3, 24 and iif
Input circuit 35 Fl, which has functions such as shaping the input pickling waveform from (including the sensor of the transmission 16), correcting the waist cloth pressure level to a predetermined level, and converting analog signal values into digital signal values. A circuit (hereinafter referred to as rcPtJJ) 35b, a storage means 35c for storing various calculation programs and calculation results executed by the CPU 351, and an output circuit 35c1 for supplying a drive signal to the fuel injection valve 36, etc. be done.

The CPU 35b controls fuel injection based on the following formula in response to engine parameter signals from the various sensors described above supplied via the input circuit 35a every time a signal pulse is input. Bu p3G's Burning Prison 1 Shot Time'I
'Calculate OUT.

TOLIT= T i X (Kru+ ° KP8
゛ KSTB ° KWOT.

KLS-T(AST-Kpn・Ko2)
-t ('l' to 8c -1-1'+nt) = 43
) Here, ] 1 is the reference value of the injection time of the fuel 1/1 injection valve 3G, and the engine rotation speed Ne and the intake pipe absolute pressure PR
Determined according to.

KTW is a water temperature increase coefficient applied during warm-up of the engine 31 for the purpose of securing an appropriate air-fuel ratio for 1j1 period warm-up, and is determined according to the engine water temperature Tw. Kp
^ is an atmospheric pressure correction coefficient determined according to atmospheric pressure.

Ksn+ is a correction coefficient for slip control, and is determined according to the slip ratio λ, the amount of change in the slip ratio, etc., as will be described later.

KIAIOT is the January Sochi conversion coefficient of the mixture when the throttle valve is fully open, KLS is the lean coefficient of the mixture when the throttle valve is fully closed, and KAST is the fuel slope increase coefficient after startup.

Further, Kpe is a predicted load correction coefficient determined according to the rate of change in the intake pipe absolute pressure PB^, and KO2 is a predicted load correction coefficient determined according to the rate of change in the intake pipe absolute pressure PB^.
This is the 02 foot offset correction coefficient determined according to the output of .

TACC and TIDL are correction variables; the former is an acceleration increase variable applied when the engine 31 accelerates, and the latter is an idle correction variable applied in the idle range of the engine 31.

The CPU 35b sends to the output circuit 35 a drive signal that causes the fuel injection valve 36 corresponding to the cylinder in which the intake stroke of the engine 31 starts to be interrupted based on the fuel injection time 1'OUT obtained as described above. d to the fuel injection valve j36.

FIG. 3 is a logic circuit diagram showing the configuration of the main parts of the CPU (351) shown in FIG.
is the detected driving wheel speed increase, (, +1 average value (r++I
! L+ωR+ri/2 is calculated, and the average i1 (continuous discrimination circuit 50
is the average value (ωI! + ωI!l / 2), and the judgment value VMIN (for example, 5 km / h), which indicates whether the vehicle is at an extremely low speed, is compared with the signal. However, if the latter is determined to be large, that is, if the average vehicle speed is lower than the discriminant value VMIN, a high level signal (hereinafter referred to as "11 believe") is transmitted, and if the latter is determined to be 11, a low level signal (hereinafter referred to as F) is transmitted. (referred to as "1. signal") is the drive wheel speed selection circuit 51.
Output to.

The driving wheel speed selection circuit 51 selects the detected driving wheel speed 0IF1.
1ωF+! When the output from the average vehicle speed discrimination circuit 50 is 11 signals, that is, when the vehicle speed is in an extremely low speed range, the one with the smaller value, that is, the one indicating a lower wheel speed is selected (low selection method); The output part (shi) is 1. At a signal, that is, when the vehicle speed is not in the extremely low speed range, the larger value, that is, the one indicating a higher wheel speed is selected (high select method), and the detected driving wheel speed ωFL or ω is selected.
Let FR be the driving wheel speed Vw of the above equation (1). The driven wheel speed selection circuit 52 detects the detected driven wheel speed ωl! L, O)T
! Among R, the one on the same side as the detected driving wheel speed ωFL or ωFR selected by the driving wheel speed selection circuit 51 is selected, and the selected detected driven wheel speed ωI! Or let ωRR be the vehicle speed V in the above equation (1).

By the output signals from these selection circuits 51 and 52,
The slip ratio calculating circuit 53 calculates the slip ratio λ based on the above equation (2). A differentiation circuit 54 calculates a differential value of the slip ratio based on the output signal from the slip ratio calculation circuit 53. Further, the setting circuit 60 uses a signal representing a gear ratio output from a sensor provided in the transmission 16 to generate a correction coefficient kl and a correction coefficient according to the first threshold value λ1 of the slip ratio, respectively, based on the gear ratio. A variable C1, a correction coefficient 2 corresponding to the second threshold value λ2 of the slip ratio, a correction variable C2, a correction coefficient r1 and a correction variable F+ that determine the first slip ratio change amount basis 21g value λ1.

Second slip rate variation basis! II: Set the correction coefficient r2 and correction variable F2 according to the value ^2. Note that the correction coefficients rl, r2 and correction variables Fl, F2 are set to compensate for the control delay from when an activation command is issued to the fuel supply control device until the device actually operates. Ru.

The first speed calculation circuit 61 receives the output signal representing the vehicle speed V from the driven wheel speed selection circuit 52 and the first threshold IIl! of the slip rate from the setting circuit 6°. (Correction coefficient k according to λ1]
and the complementary jI′E variable C] and the output signal, the following equation (
4), determine the first predetermined speed value VRI.

VR1=ktV+G+ (4) The relationship between the slip rate and the first threshold value λ1 at this time is:
λ1-(VRI-V)/VI! It becomes +. Further, the first speed '11 circuit 61 compares the calculated first predetermined speed value VRI and the first speed F limit value v01, and sets the larger value of the two to the slip ratio. Let be a first base 21++ velocity value corresponding to a first threshold oil.

Further, like the first speed calculation circuit 61, the second speed calculation circuit 62 receives the output signal from the driven wheel speed selection circuit 52 and the second threshold value λ2 of the slip ratio from the setting circuit 60.
The second predetermined speed value VR2 is determined based on the following equation (5) using the correction coefficient 2 corresponding to the correction coefficient 02 and the output signal representing the correction variable 02.
of the second predetermined speed value VCR2 and the second lower speed limit value VC2 is determined as the second base speed value corresponding to the second threshold value λ2 of the slip ratio.

■2V+C2 to R2- (5) The first correction circuit 65 receives the output signal from the driven wheel speed selection circuit 52 and the first correction signal determined for each gear ratio from the setting circuit 60.
Correction coefficient r1 according to slip ratio change speed reference value ^1
and the correction variable F1 and the output signal, the following equation (6) is obtained.
Based on the first slip ratio change amount reference value ^1, the vehicle speed V
Correct accordingly.

^+=r+V+F+ −(6) Also, the second correction circuit 66 is also the same as the first correction circuit 65.
Similarly, the output signal -l:)- from the driven wheel speed selection circuit 52 and the correction coefficient according to the second slip ratio change speed base value ^2 determined for each gear ratio from the setting circuit 60. With r2 and the output signal representing the correction variable F2,
Based on the following equation (7), the second slip ratio change amount base tl'
J (correct il^2 according to vehicle speed V.

^2=r2V+F2- (7) The first slip ratio mentioned above. Second threshold value λ1. λ
2 and 1st. Second slip ratio change reference value ^1. λ2
are λ1 × λ2 and λ1 × λ at any gear ratio.
It is set so that the following relationship 2 is satisfied.

The excessive sentence judgment circuit 55 receives the output signal from the differentiating circuit 54,
The differential value of the slip rate is determined by comparing the output signal representing the second base rilI value λ2 from the second supplementary outlet m path 66.
The base of
Output a signal.

The first predictive control determination circuit 58 compares the output signal from the differentiating circuit 54 and the output signal from the first correction circuit 66 to determine the differential value of the slip rate. 1st
When it is determined that the value is larger than the reference value λ1, the AND circuit 5
9, and in the case of that pond, outputs an L signal. The second predictive control determination circuit 63 compares the output signal from the drive wheel speed selection circuit 51 with the output signal from the first speed calculation circuit 6 and determines whether the drive wheel speed Vw reaches the first threshold of the slip ratio. When it is determined that the speed is larger than the first reference speed value corresponding to the value λ1, an 11 signal is output to the AN I) circuit 59, and in other cases, a double signal is output.

When the A N D circuit 59 receives the 1-1 signal from both the first and second predictive control determination circuits 58 and 63, the A N D circuit 59
An H signal is output via the R circuit 56.

The excessive λ determination circuit 64 compares the output signal from the drive wheel speed selection circuit 51 and the output signal from the second speed calculation circuit 62, and determines that the drive wheel speed Vw is at the second threshold value λ2 of the slip ratio. When it is determined that the speed is larger than the second base 1llll speed value corresponding to , an II times signal is outputted via the OR circuit 56.

As mentioned above, (1) ^> Huh? (excessive slip rate speed prevention), (''1) λ>λ1gλ>λ+ (Fit! control) or (jii)^)^2 (excessive slip rate prevention) when any of the following conditions is met: In this case, a signal multiplied by II is outputted via the OR circuit 56, and in this case, the fuel
By executing a fuel cut (hereinafter referred to as "fuel cut") and reducing the torque of the driving wheel TI, +2, the slip ratio λ or the slip ratio change speed ^ is reduced,
The slip rate λ is controlled to a desired value. Below, OR circuit 5
6 is output from the fuel signal I/signal
(FCM signal) ((b)(]) in FIG. 5), and the driving region of the vehicle 1 where the fuel cut signal is on is called the fuel cut region ((c)(1) in FIG. 5).
).

0; 1 First and second predictive control determination circuits 58 and 63
The signal is also output to the OR circuit 67, and the signal is output to the OR circuit 67.
outputs the 11 signal when at least one of the output signals of the first and second predictive control determination circuits 58 and 63 is an H signal, that is, when either condition ^〉statement 1 or 〉λ1 is satisfied. do. Hereinafter, the signal outputted from the OR circuit 67 will be referred to as a standby signal (STB borrowed) ((1) and (2) in FIG. 5).・The driving area of the vehicle with the signal off is set to the standby area ((c in Figure 5)
)(2)) The operating area of the vehicle 1 other than the standby area and the fuel cut area is referred to as an off-standby area ((C)(3) in FIG. 5).

The standby area is set according to the setting conditions of the area (Ku〉^l or λ
〉λ1) and fuel cut area setting conditions (λ〉^
1η λ〉λ1, etc.), the operation immediately before the vehicle 1 transitions from the off-standby area, which is the normal driving area, to the fuel cut area where fuel cut should be performed, or vice versa. Corresponds to the area (
(a) and (c) in Fig. 5). The purpose of setting such an operating region is to set the engine 31 in this region as described later.
In order to appropriately control the fuel 1"l lit supplied to the This is to prevent the temperature rise of the catalyst/12 and the occurrence of afterfire, as well as to improve drivability by preventing driving shock and the like.

Further, the first vehicle speed '1' separate circuit 68 is connected to the vehicle speed setting circuit 5.
2 and a first predetermined value V+(
For example, when the latter is larger than the former, that is, when V (V+ is established), a first vehicle speed determination signal (FCM+ signal) is output. Vehicle speed discrimination circuit 69 MOMI (17) 1r speed ゛1'q separate circuit 68 and Ii'TI, 1 (signal representing speed V and a second predetermined value larger than the first predetermined value V1) V
2 (for example, 20 km/l+) and a base 711i signal, and when V (V 2 holds true), a second multiplex discrimination signal (FCM2 Shinsou) is output.

FIG. 4 is a control program for performing slip control according to the generation states of the fuel cut signal, standby signal, etc. outputted by the logic circuit of FIG. 3, and other operating parameters. ) The C signal is executed every time a pulse occurs.

First, in step 401, it is determined whether or not a standby signal is manually input. If the answer is negative (No), that is, the standby signal is not input and therefore the vehicle is in the off-standby region, step 4
Proceeding to step 02, it is determined whether the second flag F■, GFCT2 is equal to O. This second flag FLGFCT2
When the standby signal is input, that is, when the vehicle 1 is in the standby area or the fuel cut area,
It is set to J in step 419, which will be described later, and the car ff
4] is in the off-standby region, it is set to O in step 416, which will be described later.

njJ step 402 is negative (No), that is, the second
If the flag F L G rcr2 is equal to 1, and therefore the current loop is a loop immediately after transitioning to the off-standby region, the process advances to step 403.

In this step 403, the timer T and TRC consisting of down counters are set to a predetermined time trgc (for example, 2.0 seconds) and started, and then in step 404, the engine rotation speed Ne is increased to a predetermined number of times NerRc (for example, 2.0 seconds).
, 300 rpm).

The answer to step 404 is i'r constant (Yes), that is, N
When O>NerPc holds true, the process proceeds to step 405, where the third control variable CUFCTI is set a fifth predetermined number of times N
4 (for example, 2), and then in step /106 J3 sets the slip control correction coefficient Ksrn to a lean predetermined value X5TR2 (for example, 0.8
) (section A of (cl) (3) in FIG. 5). Next, the process proceeds to step 406a, where the water temperature increase coefficient Krw is set to a predetermined value Kywo, and then the process proceeds to step 411, which will be described later.

FIG. 7 shows the predetermined value KTILI depending on the engine water temperature Tw.
An example of a KTWO table in which O is set is shown. That is, according to the figure, the predetermined value 1 (TILIO is the engine water temperature Tw from the relationship with the three boundary values 1-Wl to Ttu3 (for example, -10°C, +20°C, and +50°C, respectively) of the engine water temperature Tw. is less than l”w+ or ]゛W
When the value is 3 or more, the first predetermined value is set to WO+ (for example, 1.00), and when the value is 1゛w1 or more and less than TW2, the second predetermined value is set.
Tw
When the value is 2 or more and less than Tw*, the third predetermined value is set to WOI.
(for example, 0.95).

When the answer to step 404 is negative (No), that is, when engine rotation speed Ne≦predetermined rotation speed Neryc holds true, the process proceeds to step 407, where the third control variable CLJF
Set the value O to CLI, and then set the slip control correction variable KST11 to 1.0 in step 408.
Go to +1.

If the answer to step 402 is affirmative (Yes), that is, the second flag FLGFCT2 is equal to O, and therefore both the previous loop and the current loop are in the off-standby region, the process proceeds to step 409, where the third control variable CUFCT3 is Determine whether or not is equal to 0. If the answer to step 409 is negative (No), that is, the third control variable CUrcrs is not equal to 0, step 41
0, subtract the value 1 from the third count number CUFCIF, then execute step 406 and proceed to step 4]1. The answer to step 409 is affirmative (Yes).
), that is, when the third control variable CUFcT3 is equal to 0, the step 408 is executed and the process proceeds to step old 1.

If the engine speed Ne is high immediately after the vehicle shifts to the off-standby region, as shown in "-", the slip control correction coefficient KSTB is equal T I) C several times or set to a value smaller than the normal value after this ((d) in Figure 5)
(+)). As a result, the air-fuel mixture supplied to the engine 31 is made lean at the beginning of the release of the fuel cut.
Since the output of the engine 31 is reduced compared to the normal output in this range, it is possible to prevent a shock due to a sudden recovery of the driving i/rook. Further, the reason why the above-mentioned lean operation is not performed when the engine speed Ne is small is to prevent engine stall.

Note that instead of the above-mentioned lean operation, control may be performed to delay the ignition timing. Since the output of the engine 31 is reduced by delaying the ignition timing, in this case as well, the same effect as that of lean-burning can be obtained.

Next, proceed to step old 1, and count values T", ']'RC of timer T and TRC set in step 403.
It is determined whether or not is equal to O. This answer is negative (No)
, that is, the count value i'' is not equal to T RCM O, and therefore, if the predetermined time LTIIC has not elapsed since transition to the off-standby area, the third flag FLGpcT is set in step old 2 and step 413.
z and the fourth flag F, LG, and FCT4 are set to l, respectively, and the process proceeds to step 416, which will be described later.

If the answer to step 411 is affirmative (Yes), that is, the timer value G and TRC are equal to O, and therefore the predetermined time L TlIC has elapsed since the transition to the off-standby region, in step 4]4 and step 415, the Third flag FLGFCT3, fourth flag FLGF
Set CT4 to O, respectively, and then proceed to step 416.

In step 416, the second flag FLGrcr of nij
2 is set to O, and then in step 417, the first flag FLGFCTI is set to 0, and then the process proceeds to step old 8, and the step 406 or step 4 is performed.
The slip control correction coefficient KSTR set in step 08 is applied to the above equation (3) to calculate the fuel oil injection time 1'OUT, and fuel injection is performed based on the injection time ']'OUT, and this program is executed. finish.

When the answer to step 40+ is affirmative (Yes), that is, the standby signal is input, and the vehicle is therefore in either the standby region or the fuel cut region, the process proceeds to step old 9 and the second Flag F
Set L Gpct2 to 1.

Next, the process proceeds to step 420, where a predetermined value X5TI+ for the standby region and a predetermined value XT for the fuel cut region
The RC1 first and second predetermined times No and N+ are stored in the X5TR table and xTI stored in the storage means 35c, respectively.
! Select from the c table, No table, and N1 table according to the engine rotation speed Ne.

Figures 6(a) to 6(d) show examples of these tables, and according to the figure, each table has an engine speed N.
6 into 5 regions, and for each region
rB, XrI! c, No, and N1 are each set as constant values. That is, the boundary values of the engine rotation speed Ne are Ne+, Ne2, Ne3 in descending order of the engine speed Ne.
and Ne4 (e.g. 2, 300.2, 800, respectively).
3.300 and 4,800 rpm), engine speed Ne is less than Ne+, less than Ne2, N0
2 or more and less than Ne3, Ne3 or more and less than Ncz, and Neq or more. II, III, IV and ■. The predetermined values X5TB for the standby region are X5TBI, X5TB2, X5TB3, X, 5TB4 for regions 1 to 2 in order from the region l side, that is, from the low rotation region side.
and X5TB5 (e.g. 0.50.0.60 respectively
．． 0.80, 0.80 and 1.70) are set. Similarly, the predetermined value X nc for the fuel cut region, the first and second predetermined number of times No, and N+ are all smaller than l (7) for XTRC in order from the region I side for the region 1-V. Xr*c+-Xr*c5 (e.g. 0.35.0.40.0.40.0.45 and O, respectively)
However, for NO, No+ to N05 (for example, 1 each
．． 2.3.4 and 255), but for N1, N++~
N15 (for example, 1.2.3.3 and O, respectively) are set.

These tables are based on engine characteristics and three-way catalyst 4.
It can be set in various ways depending on the type of item 2, etc.

Next, the process proceeds to step /121, where it is determined whether or not a fuel cut signal is being input. This answer is negative (N
o), that is, the fuel cut signal is not manually operated,
Therefore, when the vehicle is in the standby area, the process proceeds to step 422 and the third flag F L G
Determine whether Fen is equal to O. This step 4
The answer to 22 is 111 (Yes), that is, the third flag F
If L G rcr* is equal to 0, step 423
The fourth flag F L G rCTq is set to 0, which is negated (No), that is, the third flag F L G FC is set to 0.
When T II is equal to 1, the fourth flag F L G pcTq is set to 1 in step 424, and then the process proceeds to step 425.

In this step 425, all correction coefficients other than the atmospheric pressure correction coefficient Kr△ among the correction 1F coefficients applied to the above equation (3) are set to 1.0, and [1° all correction variables are set to 0.
By setting these correction coefficients and correction variables. This makes it possible to eliminate the influence of fluctuations in these correction coefficients and correction variables on the fuel injection time Toor, so the slip control correction coefficient K S T n and the water temperature increase coefficient KTW are set again in steps 426 and 427, which will be described later. Coupled with this, the air-fuel mixture supplied to the engine 31 can be made to have an optimum desired air-fuel ratio.

Therefore, by reducing the amount of unburned fuel 1' discharged, the occurrence of afterfire and the performance deterioration of the three-way catalyst/I2 caused by the temperature of the three-way catalyst/I2 can be prevented. Can be done. Also, the reason why the atmospheric pressure correction coefficient KT^ is not canceled is because the engine 31
This is because this coefficient is multiplied in order to prevent the air-fuel ratio of the air-fuel mixture supplied to the engine from changing, so it is necessary to apply this coefficient in the standby region as well as in the off-standby region.

Next, the process proceeds to step 426, where the slip control correction coefficient 1 is
(Set STB to the predetermined value X5rn for the standby area set in step 420 ((
d) Section C of (3)). During the transition between the off-standby area, which is a normal operating area, and the fuconyl cut area, where a fuel cut is performed as described later, the engine 3
The air-fuel ratio of the air-fuel mixture supplied to the three-way catalyst/12 tends to fluctuate, which makes the combustion characteristics of the engine 31 unstable, and a large amount of unburned fuel is produced, causing the temperature of the three-way catalyst/12 to change. JJ? and afterfire is likely to occur. Also,
The fuel characteristics of the engine 31 vary depending on the engine rotation speed Ne. Furthermore, in the low rotational speed range of the engine 31, a resonance phenomenon related to the suspension of the vehicle body occurs, and drivability tends to deteriorate. Therefore, as described above, by using the predetermined value X5TB for the standby region set according to the engine speed Ne as the slip control correction coefficient, the temperature of the three-way catalyst can be adjusted over the entire engine speed range. In addition to preventing the occurrence of afterfire, it is also possible to improve drivability.

Note that the predetermined value X5rs for the standby area is set to the high rotation side (
In region V) of FIG. 6, the mixture is enriched to 1.0 or higher, but this is due to the increased heat of vaporization of unburned components due to the enrichment of the mixture.
This is because the cooling effect of the gas is promoted and the temperature can be prevented from reaching 2H. This predetermined value X for the standby area on the high rotation side
Conversely, by setting STR to a value less than 1.0 depending on the type of three-way catalyst 42, etc., the air-fuel mixture may be made lean.

Next, the process proceeds to step 427, where the water temperature increase coefficient KTILI canceled in step 425 is set to the predetermined value K.
Set to TILIO. This makes it possible to make the air-fuel mixture supplied to the engine 31 lean in the standby region, which, in combination with the cancellation of the correction coefficient and variable in step 425, prevents the occurrence of afterfire and the temperature JJ of the three-way catalyst 42. Deterioration of the performance of the three-way catalyst 42 can be prevented even when the engine 31 is at a low temperature.

Next, execute step 7 and step 418 to obtain the slip control correction coefficient KSTB and water temperature increase coefficient KT set in steps 426 and 427, respectively.
U+ is applied to perform one fuel injection and end this program.

If the answer to step 421 is affirmative (Yes), that is, fuel cut Shinso has been input, and therefore the vehicle is in the fuel cut region, the process proceeds to step 428, and the fourth flag FLGFCT4 is equal to O. Determine whether or not. The answer to this step 428 is affirmative (
Yes), that is, when the fourth flag I'LGFCT4 is equal to O, the third flag F is set in step 429.
After setting L G FCT3 to 1, step 4
30, set n;j first flag F L G rcrt to 1
, and further executes step 431 to perform a fuel cut (section D of (d) (3') in FIG. 5).
Exit this program.

The fourth flag F L Grcrq is set to the value O when the timer value of the timer ']' and TRC is equal to O, as is clear from steps 411 and 415 described above. be. That is, if the vehicle shifts to the fuconyl cut region after staying in the off-standby region for a predetermined time LTIIC or more, the answer to step 428 becomes l'r'AI (Y es ), and the fuel cut continues. When the vehicle shifts to the fuel cut area, if the time it has remained in the off-standby area for a long time is excessive slip when accelerating from an extremely low previous slip rate of 0 or close to 0. Since it is expected that the fluctuation range and rate of change of the slip ratio λ will become large, the following
By continuing the fuel cut as in 2, the driving force of the engine 31 can be reliably reduced and the slip ratio λ can be quickly converged to a desired value.

Note that it is also possible to set a condition different from "-" as a condition for continuing the fuel cut.

For example, when the throttle valve 33' changes from a fully closed state to a concave state (IN
or the rate of change of the throttle valve opening OTl+ exceeds the predetermined value twice, and the drive wheels II, 1
When it is determined that the slip state in item 2 is excessive, the fuel cut may be continued for a certain period of time, thereby achieving the same effect as in item 1.

If the answer to step 428 is negative (No), that is, when the fourth flag F T, (',;
G F (: Determine whether Tl is equal to O or not 3, this first flag FLGFCTI is 0;
7 and STEP 430, it is set to 1 when a fuel cut is executed in the fuel cut region, and is set to O in other regions.

If the answer to the step 432 is affirmative (Yes), that is, the first flag F L G peTt is equal to O, and therefore the current loop is the loop immediately after transitioning to the fuel cut region, the process proceeds to step 433 and the FCM2
Whether the signal is input or not, that is, the vehicle speed V or the second
PIJ is determined to determine whether or not it is smaller than a predetermined value 2. If the answer to this step 433 is affirmative (Yes), that is, F CM
If 2 Shinkan is manually created and therefore V < V 2 holds true, the process proceeds to step 434, where the second predetermined number of times N1 selected in step 420 is added to the fourth predetermined number of times N, + (for example, 1 ), then step 4
Proceed to step 35.

In this step 435, it is determined whether F C:, M + signal) is manually operated, that is, whether the vehicle speed V is smaller than the first predetermined value v1. This answer is affirmative (Ye
s), that is, when the F CM 1 signal is input and therefore v and Vl hold, step 436
The process proceeds to step 437, where the third predetermined number of times N2 (for example, 1) is subtracted from the first predetermined number of times NO selected in step 420, and then the process proceeds to step 437.

If the answer to step 435 is negative (No), that is, FCM
+ Shinkan is not input, therefore V2V5 is established, and the answer to step 433 is negative (N
o), that is, when the FCM2 signal is not input and therefore V2V5 is established, step 43 is performed.
Proceed to step 7. That is, when V<■2 holds, the subtraction correction jE of the first predetermined number of times NO and addition correction of the second predetermined number of times N1 is performed, and when V2≦Vku■1 holds, the addition correction of the second predetermined number of times N1 is performed. When V2V5 holds true, no correction is made for both predetermined times.

In step 437, the first control variable CUFCTI
, selected in step 420 or step=3
5- Complement this with the knob 436 11', and set the first predetermined number of times No.
is set, and then the process proceeds to step 438.

If the answer to step 432 is negative (No), that is, the first flag FLGFCTI is equal to 1, and therefore this is the second or subsequent loop after the current loop transitions to the fuel cut region, then step 7 directly n; 438
Proceed to. That is, the route of steps 432 to 437 described above is executed only once immediately after transition to the fuconyl cut region.

lf:j iiQ In step 438, 1); 1 determines whether the first control variable CLIFCTI is equal to 0 or not. If this answer is negative (NO), that is, CUrcT+ is not 0, the process proceeds to step 439 and the second control variable CU
For Fcn, 11; selected in 1 stap/120,
Or 1); Set the second predetermined number of times N1 corrected in step 434 of I. Next, in step 440, the value 1 is calculated from the control variable CUFCTI of the fil, and further steps 430 and 431 are executed to cut the fuel ((d) in FIG. 5).
3) Ward fJ [eye ga), end this program.

If the answer to step 438 is affirmative (Yes), that is, the first control variable CUFCTI is equal to 0, the process proceeds to step 441, where it is determined whether the second control variable CtJpcr2 is equal to O or not. If the answer to step 441 is negative (No), that is, CUFCT2 is not 0, the process proceeds to step 442, where the value 1 is subtracted from this second control variable CUFCT2. The process then proceeds to step 443, in which all correction coefficients and correction variables are canceled as in step 425. Next, the slip control correction coefficient KS
As T11, set the predetermined value XTlIC for the fuel cut region selected in step 420 (section 1Σ2 in (d)(3) of FIG. 5), and in step 445 set water temperature increase coefficient 1 (TILI to 1.0). do.

Furthermore, the step 418 is executed, and fuel injection is performed by applying these correction coefficients and correction variables to the equation (3),
Exit this program.

If the answer to step 441 is affirmative (Yes), that is, if the second control variable CUFCT2 is equal to 0, the process proceeds to step 446, in which the first control variable CLJFCTI is set a first predetermined number of times as in step 437. ,
Next, steps 440, 430 and 431 are executed, the fuel is cut, and the program is terminated.

As shown in ``2'' above, even if the +1c car is in the fuconyl calami region, when the fourth flag Fl and pcTq are equal to 1, the fuel cut is not continued but is turned to NO the first predetermined number of times. The execution of the fuel cut for an equal number of 'I'1C times and the release of the fuel cut for the number of DC times of 'I' equal to the second predetermined number of times N1 are alternately repeated ((1) in Fig. 5). Section E) of (3).The fourth flag F L G rcTq is set to 1 when the axle shifts to the fuel cut 9'I region 1), as is clear from steps 1 and 413. ;j remains in the off-standby area at a predetermined time fl'l
L Tl! (If less than: or step 429.42
As is clear from 2 and 424, this is a case where the vehicle transitions from the fuel cut area to the standby area and then returns to the fuco-nyl cut area without transitioning to the off-standby area. In other words, this is a case where slip control is performed at relatively short time intervals, and in such a case, the variation range and rate of change of the slip ratio λ are small, so it is difficult to execute and release the fuel cut as described above. By performing each at a predetermined TDC number, driving shock caused by a sudden decrease in the driving torque of the engine 31 can be prevented and drivability can be improved.

Also, in this case, when the fuel cut is released, the engine 3
The air-fuel ratio of the air-fuel mixture supplied to step 420
The predetermined value X for the standby region is set as the slip control correction coefficient KSTR in the standby region.
5TR is set according to the engine speed Ne, the three-way catalyst 4 is set over the entire range of the engine speed Ne.
2. Temperature-1 - The occurrence of shoulder and afterfire can be prevented, and drivability can be improved -1.

Furthermore, as described above, the first predetermined time-:I! determines the TDC number ratio for executing and canceling the fuel cut. The I-number No. and the second predetermined number of times N1 are also basically set according to the engine speed Ne, so that the predetermined value X5TR for the standby region and the predetermined value X for the fuconyl cut region, It is possible to obtain the same effect as in the case described above in which TPC is set according to engine speed Ne.

In this embodiment, the first and second predetermined times NO and N+ are set according to the engine rotation speed Ne, but the invention is not limited to this, and the detected slip state of the vehicle, for example, the slip rate It may be set according to λ or the amount of change in slip ratio λ. That is, the slip ratio λ or the amount of change in slip ratio λ is large (J and it is necessary to reduce the instantaneous I/Lux of the engine 31 more significantly, so the slip ratio λ or the amount of change in slip ratio λ is First predetermined number of times N
By setting O or the second predetermined number of times N+, the air-fuel ratio of the air-fuel mixture can be controlled to an appropriate value that directly reflects the slip condition of the vehicle. Therefore, engine 3
By appropriately reducing the driving force of 1, the slip ratio λ or the slip ratio change amount λ can be quickly converged to a desired value.

Furthermore, a predetermined value for the standby region X5TR, a predetermined value for the fuel cut region XTlIC1, a first predetermined number of times No.
Alternatively, instead of setting the second predetermined number of times N1 according to the engine speed Ne, or in addition to this, it may also be set according to the engine load, for example, the intake pipe absolute pressure PBΔ or the throttle opening r opening degree On+. In other words, since the amount of reduction in the driving force of the engine 31 due to slip control varies depending on the magnitude of the load on the engine 31, when the air-fuel ratio of the air-fuel mixture is set to suit a high-load operating state, it will be reduced to a low-load operating state. On the other hand, if the setting is made to suit low load operating conditions, there will be insufficient control during high load operating conditions. Therefore, the predetermined value Xsr+
+, XTRC, by setting a predetermined number of times No. or N1 according to the engine load, air-fuel ratio control (n11
It is possible to carry out this process in an appropriate manner and ensure good drivability. In this case, the predetermined value X sr is determined by both the engine speed Ne and the intake pipe absolute pressure Y)
When setting B, etc., it is of course possible to map the predetermined value X5TR, etc. using the engine speed Ne and the intake pipe absolute pressure PsΔ.

In addition, Jυjtl for executing and canceling fuel cut.
ll can be set in various @ manners, for example, the first predetermined number of times No and the second predetermined number of times N1 may be set according to the wheel speed on the driven wheel side. In addition, the period for executing and canceling the fuel cut will be changed as described above.
Instead of using the C number ratio, it is also possible to use a time ratio depending on the operating state of the engine 31, or to use a fixed value when simplifying the control device.

(Effects of the Invention) As described in detail, the present invention provides a drive wheel slip control device that includes a slip detection means for detecting a slip state lower than an excessive slip state of the drive wheels, and a slip detection means that detects a slip state lower than an excessive slip state of the drive wheels, and a correction value setting means for setting a correction value for correcting the amount of fuel supplied from the fuel 1'=1 supply means; and a correction value set by the correction value setting means when the slip detection means detects the low slip state. Since the present invention is equipped with a correction value invalidating means for invalidating the correction value, when the driving wheels shift to excessive slip, the influence of the invalidated correction value on the air-fuel ratio of the air-fuel mixture is suppressed. , the air-fuel mixture is controlled to an optimal desired air-fuel ratio to reduce the unburned fuel consumption to 1
)1 output amount can be reduced, and therefore, the generation of afterfire at this time and the performance deterioration of the three-way catalyst in the exhaust system can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a vehicle equipped with the drive wheel slip control device of the present invention, FIG. 2 is a block diagram of a fuel supply control device that controls the l/lux of the drive wheels, and FIG. Logic circuit diagram, Figure 4 is a flowchart of a control program for performing slip control, and Figure 5 shows the relationship between the slip ratio or the amount of change in slip ratio, the output signal from the logic circuit diagram in Figure 3, and slip control. 6 shows a table of predetermined values and predetermined times applied to the control programs of FIGS. 4 and 5. FIG. 7 shows a table of predetermined values K TWO of the water temperature increase coefficient KTW. The figure is a characteristic diagram of the frictional force between the tire and the road surface with respect to the slip rate. 1...Vehicle, 11.12...Drive wheel, 21.22...
Drive wheel speed sensor, 23.24... Driven wheel speed sensor,
3...Engine, 35...Electronic control unit (ECU), 36...Fuel injection valve F.

Claims (1)

[Scope of Claims] 1. A fuel supply means for supplying fuel to an engine, an excessive slip detection means for detecting an excessive slip state of a drive wheel of a vehicle, and when the excessive slip detection means detects an excessive slip state. A drive wheel slip control device comprising: a fuel supply stop means for stopping fuel supply from the fuel supply means; a slip detection means for detecting a slip state of the drive wheels lower than the excessive slip state; a correction value setting means for setting a correction value for correcting the amount of fuel supplied from the fuel supply means according to a state; and a correction value setting means for setting a correction value by the correction value setting means when the slip detection means detects the low slip state. A driving wheel slip control device comprising: a correction value invalidation means for invalidating the correction value. 2. The correction value set by the correction value setting means is at least one of an acceleration increase correction value, a high load increase correction value, a post-start increase correction value, an idle correction value, and a low load reduction correction value. A drive wheel slip control device according to claim 1. 3. The excessive slip detection means detects the excessive slip when at least one of the conditions that the slip ratio is larger than the first predetermined slip ratio and the slip ratio change amount is larger than the first predetermined slip ratio change amount is satisfied. detecting a state, and the slip detection means detects that the slip rate is the first slip rate.
one of the following: a condition in which the amount of change in the slip rate is greater than a second predetermined amount of change in the slip rate, which is less than the first amount of change in the predetermined slip rate; 3. The driving wheel slip control device according to claim 1, wherein a slip state lower than the excessive slip state is detected when the following condition is satisfied. 4. The excessive slip detection means detects an excessive slip state by satisfying a condition that the slip ratio is larger than the second predetermined slip ratio and a condition that the slip ratio change amount is larger than the second predetermined slip ratio change amount. The driving wheel slip control device according to any one of claims 1 to 3, characterized in that the drive wheel slip control device detects the slippage of the driving wheel.