JPH07290999A - Traction control device of vehicle - Google Patents

Abstract

PURPOSE:To secure favourable controllability even at the time when an engine control mode is switched over to an exhaust gas reduction mode to reduce exhaust gas. CONSTITUTION:A catalytic temperature sensor 60 is provided on a catalytic converter 48 set in an exhaust passage 47 of an engine 5, and at the time when catalytic temperature which a signal from the sensor 60 shows is higher than a specified value, a traction control mode by engine control is switched from a normal mode over to an exhaust gas reduction mode. In this case, when the exhaust gas reduction mode is selected, a target value of engine control is increased higher than the normal mode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traction control device for a vehicle, and more particularly to a traction control device for a vehicle equipped with an engine having an exhaust system provided with a catalytic converter for purifying exhaust gas.

[0002]

2. Description of the Related Art In some vehicles such as automobiles, so-called traction control is performed in order to prevent the driving wheels from slipping due to excessive driving torque and declining in acceleration during acceleration. This traction control is performed when the driving wheels are excessively slipped due to excessive driving torque, for example, by reducing the engine output or applying a braking force to the driving wheels, thereby rotating the driving wheels. The slip amount calculated on the basis of the above is converged to a predetermined target value. In this case, retarding the ignition timing (retard) or limiting fuel injection (fuel cut) may be performed as a method of reducing the engine output. In this case, for example, the control level is calculated based on the slip amount of the driving wheels, the ignition timing is retarded according to a table for engine output reduction set with the control level as a parameter in advance, and fuel injection to a required number of cylinders is performed. Will be stopped.

On the other hand, an engine mounted in this type of vehicle is provided with a catalytic converter for purifying exhaust gas in the exhaust system. In that case, the ignition timing is caused when the drive wheels excessively slip. If the engine output is reduced by retarding the fuel or cutting the fuel, the following inconvenience may occur.

That is, when the ignition timing is retarded, the amount of unburned components contained in the exhaust gas relatively increases, and the so-called post-combustion state becomes long and the exhaust gas temperature rises. Due to the action, the oxidation reaction in the catalytic converter may become active and the temperature may rise to high temperature, which not only may deteriorate the purification characteristics of the exhaust gas, but also may cause thermal deterioration of the catalyst and increase the durability of the catalytic converter itself. Will also cause problems. Regarding the fuel injection limit, unless fuel cut is performed for all cylinders, unburned components discharged from the cylinders where fuel cut is not performed will be performed from the cylinder where fuel cut was performed before reaching the catalytic converter. There is a possibility of re-combustion by touching the rich oxygen in the exhaust gas that is discharged, and the reheating of the exhaust gas accompanied therewith causes the same problem as described above.

To solve such a problem, for example, as disclosed in Japanese Unexamined Patent Publication No. 5-1613, a traction control device for a vehicle equipped with an engine having a catalytic converter in its exhaust system is used as a catalytic converter. A temperature sensor that detects the floor temperature is provided, and when the floor temperature indicated by the signal from the temperature sensor is equal to or higher than a predetermined value, the engine control mode is changed from the normal mode to the exhaust gas reduction mode that lowers the temperature of the exhaust gas. It is thought to do. According to this, when the temperature of the catalytic converter is high, for example, retardation of the ignition timing is not performed, so it is expected that abnormal temperature rise of the catalytic converter is avoided and the above problem is solved.

[0006]

However, even in the prior art described in the above publication, there is still room for improvement as described below.

That is, in the exhaust gas reduction mode,
For example, when the engine output is reduced by one step, the control of the engine output becomes rough, such as the fuel cut being performed where the ignition timing should be retarded normally. Therefore, for example, the torque transmitted to the drive wheels drops too much, which causes the driver to feel stall.

According to the present invention, an engine having a catalytic converter in its exhaust system is mounted, and traction control of a vehicle is provided with traction control means for suppressing an excessive driving force at least by controlling the engine when the drive wheels excessively slip. The present invention addresses the above-described problems in the device, and an object thereof is to ensure good controllability even when the engine control mode is switched to the exhaust gas reduction mode for reducing exhaust gas.

[0009]

That is, according to the invention of claim 1 of the present application (hereinafter referred to as the first invention), an engine having a catalytic converter for purifying exhaust gas is mounted in an exhaust system, and drive wheels are provided. In a vehicle equipped with traction control means for suppressing an excessive driving force by controlling the engine at least during excessive slip of the engine, when the catalytic converter is in a high temperature state, the engine control mode is set to reduce the exhaust gas from the normal mode. A mode switching means for switching to the gas reduction mode and a control means for performing control so that the control amount of the engine becomes a value on the torque up side as compared with the normal mode when the exhaust gas reduction mode is executed are provided. To do. Here, the control amount of the engine may be directly changed to a value on the torque-up side, or the control amount may be indirectly controlled to the value on the torque-up side. Is also good.

The invention according to claim 2 of the present application (hereinafter referred to as the second invention) includes the control means in the first invention,
It is characterized in that the engine control target value is increased when the exhaust gas reduction mode is selected.

The invention of claim 3 of the present application (hereinafter, referred to as the third
The invention) is characterized in that the control means in the first invention is configured to upshift the shift speed of the transmission when the exhaust gas reduction mode is selected.

Further, the invention of claim 4 of the present application (hereinafter referred to as the fourth invention) is configured such that the traction control means in the first invention is used in combination with engine control to perform brake control. The means is configured to reduce the target value of the brake control when the exhaust gas reduction mode is selected.

The invention of claim 5 of the present application (hereinafter referred to as the fifth
(Invention) is equipped with an engine having a catalytic converter for purifying exhaust gas in the exhaust system, and provided with traction control means for suppressing an excessive driving force at least by controlling the engine when the drive wheels excessively slip. In the vehicle, when the temperature of the catalytic converter is high, the mode switching means for switching the engine control mode from the normal mode to the exhaust gas reduction mode for reducing the exhaust gas, and the execution mode of the exhaust gas reduction mode, as compared with the normal mode, Control gain changing means for increasing the gain of engine control is provided.

Further, according to a sixth aspect of the present invention (hereinafter referred to as a sixth aspect), an engine having a catalytic converter for purifying exhaust gas is mounted in an exhaust system and at least the engine is operated when the drive wheels are excessively slipped. In a vehicle equipped with a traction control means for suppressing an excessive driving force by controlling the above, when the catalytic converter is in a high temperature state, a mode for switching the engine control mode from a normal mode to an exhaust gas reduction mode for reducing exhaust gas The present invention is characterized in that the switching means and the control means for performing the control so that the control amount of the engine becomes a value on the torque down side as compared with the normal mode when the exhaust gas reduction mode is executed. Here, the control amount of the engine may be directly changed to the value on the torque down side, or the control amount may be indirectly controlled to the value on the torque down side. May be.

The invention of claim 7 of the present application (hereinafter referred to as the seventh invention) includes the control means in the sixth invention,
When the exhaust gas reduction mode is selected, the engine control target value is reduced.

[0016]

According to the above construction, the following operation can be obtained.

That is, in any of the first to seventh inventions, when the catalytic converter installed in the exhaust system is in a high temperature state, the engine control mode is switched from the normal mode to the exhaust gas reduction mode for reducing the exhaust gas. . As a result, the amount of unburned components in the exhaust gas introduced into the catalytic converter is suppressed as a whole, and an excessive temperature rise of the converter is avoided.

Moreover, according to the first to fourth aspects of the invention, when the exhaust gas reduction mode is executed, control is performed so that the control amount of the engine becomes a value on the torque up side as compared with the normal mode. The required drive torque is secured and the driver does not feel stall.

According to the second aspect of the invention, since the target value for engine control is increased when the exhaust gas reduction mode is selected, the engine output is relatively increased as compared with the normal mode. The driver will not feel stall.

Further, according to the third aspect of the invention, when the exhaust gas reduction mode is selected, the shift stage of the transmission is upshifted, so the slip amount of the drive wheels is reduced, and the control amount of the engine is reduced. Changes to the torque-up side, and in this case as well, the engine output relatively rises compared to the normal mode, and the driver does not feel stall.

Further, according to the fourth aspect of the present invention, the traction control is performed by the combined use of the engine control and the brake control, and when the exhaust gas reduction mode is selected, the target value of the brake control decreases, so the brake The control amount by the engine control changes to the torque-up side by the amount by which the drive torque is reduced by the control, and even in this case, the engine output relatively rises compared to the normal mode, and the driver feels stall. It doesn't feel.

Further, according to the fifth aspect of the present invention, when the exhaust gas reduction mode is executed, the gain of the engine control increases, so that the engine output changes at a high frequency, and the fluctuation of the wheel speed is avoided. As a result, the controllability is improved.

Further, according to the sixth and seventh inventions, when the exhaust gas reduction mode is executed, the control is performed such that the control amount of the engine becomes a value on the torque down side as compared with the normal mode. Therefore, the engine output is further reduced, and the control stability is ensured.

According to the seventh aspect of the invention, when the exhaust gas reduction mode is selected, the target value for engine control is reduced, so the engine output is relatively reduced compared to the normal mode, and the control is performed. Will ensure stability.

[0025]

EXAMPLES Examples of the present invention will be described below.

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

The wheels 1 to 4 have disks 11a to 14a which rotate integrally with the wheels 1 to 4, respectively.
These discs 11a ...
Brake devices 11 to 14 including calipers 11b to 14b for braking the rotation of 14a are provided, and a brake control system 15 for braking these brake devices 11 to 14 is provided.

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

On the other hand, the booster 17 is connected with a working pressure line 22 for supplying a working pressure from a pump 21 and a return line 23 for returning excess brake oil generated in the booster 17 to a reservoir tank. The first braking pressure line 24 led from the booster 17 and the second braking pressure line 25 branched from the pump discharge side of the working pressure line 22 are electromagnetic first, Second on-off valve 2
6 and 27 are installed respectively. A check valve 28 for preventing backflow is installed in the first braking pressure line 24 in parallel with the first opening / closing valve 26. In addition, the first and second
The braking pressure lines 24 and 25 are joined at a point X, and the braking devices 13 on the left and right rear wheels 3 and 4 are joined from the joining point X.
The rear wheel braking pressure line 2 is attached to the caliper 13b, 14b of the reference numeral 14.
9 and 30 are guided, and electromagnetic type opening / closing valves 31 and 32 and relief valves 33 and 34 are installed on the braking pressure lines 29 and 30, respectively.

In that case, the first opening / closing valve 26 on the first braking pressure line 24 is opened as shown in the figure, and the second braking pressure line 2 is opened.
5 is closed and the opening / closing valves 31, 32 on the rear wheel braking pressure lines 29, 30 are opened, the brake pedal 16 is depressed by the booster 17. Braking pressure corresponding to the force is supplied to the brake devices 13 and 14 on the left and right rear wheels 3 and 4 via the first braking pressure line 24, and the braking force corresponding to these braking pressures applies to the rear wheels 3 and 4. Are braked respectively.

The engine 5 is a V-type 6-cylinder engine in which the left and right first and second banks 5a and 5b arranged in a V-shape each have three cylinders arranged in a row. 6 connected to the upstream main intake passage 42 via
43 are connected to respective cylinders in the first and second banks 5a and 5b, and the fuel injection valve 4 is provided in these independent intake passages 43 ... 43.
4 ... 44 are installed respectively. A throttle valve 45 for adjusting the intake air amount or the engine output is installed in the main intake passage 42 in conjunction with an accelerator pedal (not shown). Further, the first and second banks 5a and 5b are provided with spark plugs 46 ... 46 for each cylinder.

On the other hand, the exhaust passages 46, 46 connected to the first and second banks 5a, 5b are merged into one at the downstream side, and the exhaust gas is purified downstream from the junction. A catalytic converter 48 is installed.

The vehicle is equipped with an electronically controlled control unit 50. The control unit 50 includes wheel speed sensors 51 to 54 provided on the left and right front wheels 1 and 2 and the rear wheels 3 and 4, respectively.
From a wheel speed signal from the air flow sensor 55, a throttle opening signal from a throttle opening sensor 56 that detects the opening of the throttle valve 45, and an engine speed sensor 57 that detects the engine speed. An engine speed signal, a vehicle speed signal from a vehicle speed sensor 58 for detecting the vehicle speed of the vehicle, a water temperature signal from a water temperature sensor 59 for detecting the engine water temperature, a catalyst temperature signal from a catalyst temperature sensor 60 provided in the catalytic converter 48, etc. Enter. Based on these signals, the ignition timing control for the ignition plugs 46 ... 46 provided for each cylinder in the first and second banks 5a, 5b and the fuel injection amount of the fuel injection valves 44 ... 44 are controlled. The control and the shift control for the automatic transmission 6 are performed, and when it is determined that a predetermined traction control condition is satisfied, the traction control (hereinafter, referred to as TCS control) is performed.

Here, the ignition timing control, the fuel injection control, and the shift control performed by the control unit 50 will be described. First, the ignition timing control is generally performed as follows.

That is, the control unit 50 is
The engine speed Ne indicated by the signal from the engine speed sensor 57 and the intake air amount Q indicated by the signal from the air flow sensor 55 are added to the basic ignition timing map in which the engine speed and the intake air amount are set in advance as parameters. The final ignition timing is determined by fitting the basic ignition timing and correcting the basic ignition timing according to the signal from the water temperature sensor 59. Then, an ignition timing control signal is output so that the ignition plugs 46 ... 46 are ignited at this final ignition timing.

Further, the above fuel injection control is performed roughly as follows.

That is, the control unit 50 is
The basic fuel injection amount is set from the engine speed Ne and the intake air amount Q, and various correction amounts calculated based on the signal from the water temperature sensor 59 and the like are added to the basic fuel injection amount to determine the final injection amount. . Then, the fuel injection signal is sent to the fuel injection valve 44 so that the fuel is injected with this final injection amount.
Output to 44.

Then, the shift control is performed as follows.

That is, the control unit 50 is
By comparing the throttle opening θ indicated by the signal from the throttle opening sensor 56 and the vehicle speed Vb indicated by the signal from the vehicle speed sensor 58 with a shift map which is set in advance with the throttle opening and the vehicle speed as parameters. The optimum shift speed most suitable for the operating condition is determined, and a shift signal is output to the shift unit 49 attached to the automatic transmission 6 so that the determined shift speed is realized.

Next, the T performed by the control unit 50
The CS control will be described.

That is, the control unit 50 is
Left and right front wheels 2, which are loaded from the wheel speed sensors 51, 52
Of the 3 driven wheel speeds, for example, the smaller value is selected as the vehicle body speed Vr of the vehicle. And this vehicle speed V
The vehicle body acceleration Va of the vehicle is calculated based on the change of r, and the calculated vehicle body acceleration Va and the vehicle body speed Vr are set in advance with the vehicle body speed and the vehicle body acceleration as parameters as shown in Table 1 below. Apply to the table and set the corresponding value as the road surface friction coefficient μ.

[0042]

[Table 1] Here, as shown in Table 1 above, the value of the road surface friction coefficient μ increases as the vehicle speed Vr increases and the vehicle acceleration Va increases.

Next, the control unit 50 uses a preset map for setting a control threshold from the vehicle speed Vr and the road friction coefficient μ calculated as described above,
The control start threshold value Ss and the control end threshold value Se are set respectively. Here, the control end threshold S is more than the control start threshold Ss.
The value of e is set to a smaller value.

The control unit 50 subtracts the vehicle body speed Vr from the driving wheel speeds of the left and right rear wheels 3 and 4 fetched from the wheel speed sensors 53 and 54, respectively, to obtain the slip amount S of the left and right rear wheels 3 and 4. , S, and then arithmetically averaging them to calculate the average slip amount SAv, and the larger one of the two slip amounts S, S is selected as the maximum slip amount SHi. Then, when the maximum slip amount SHi is larger than the control start threshold value Ss, it is determined that the rear wheels 3 and 4 which are the driving wheels are in the slip state, the slip flag Fs is set to 1, and the maximum slip When the amount SHi becomes smaller than the control end threshold value Se, it is determined that the slip state is not present and the slip flag Fs is reset to zero.

Here, the control unit 50 uses the engine control and the brake control in combination to control the TC.
The S control is performed, of which the TCS control by the engine control is specifically performed as follows.

That is, the control unit 50 sets the vehicle speed Vr and the road surface friction coefficient μ calculated as described above in the map of the engine control slip target reference value in which the vehicle speed and the road surface friction coefficient are set in advance as parameters. Applying the corresponding value as the engine control target slip basic value Teo, and substituting the target slip basic value Teo and the engine control target value correction coefficient K1 into the following relational expression (1), the final value is obtained. Specifically, the engine control slip target value Te is set.

Te = Teo · K1 (1) In that case, the engine control target value correction coefficient K1
Is normally set to 1.

Then, the control unit 50 substitutes the engine control slip target value Te and the average slip value SAv into the following relational expression (2) to obtain the engine control slip target value Te with respect to the average slip value Te. The deviation ΔSe of SAv is calculated, and the current value ΔSe _(J) and the previous value ΔSe _{(J-1) of the} deviation ΔSe are substituted into the following relational expression (3), and the calculation result is the deviation change rate. D
Se.

ΔSe = SAv−Te (2) DSe = ΔSe _(J) −ΔSe _(J-1) (3) Then, the control unit 50 controls the deviation ΔSe.
And the deviation change rate DSe are compared with the basic engine control level table shown in Table 2 below to read the corresponding value as the basic engine control level L.

[0050]

[Table 2] Then, the control unit 50 substitutes the basic engine control level L read from the table of Table 2 into the following relational expression (4), and finally uses the calculation result in the range of “0 to 11”. Set the engine control level EL.

EL _(J) = EL _(J-1) + L × G (4) In this relational expression (4), EL _(J-1) is the previous value of the engine control level EL, and G is the control gain. As the value of this control gain G, 1 is normally used.

The control unit 50 applies the engine control level EL thus obtained to the engine control table shown in Table 3 below to perform fuel cut according to the control pattern corresponding to the value of the engine control level EL. Retard the ignition timing.

[0053]

[Table 3] Here, the mark X in Table 3 indicates the fuel cut. That is, as the value of the engine control level EL increases, the number of cylinders whose fuel is cut increases, and the engine output decreases accordingly. Even if the number of cylinders for which fuel is cut is the same, if the ignition timing is retarded, the engine output will be further reduced.

In this embodiment, as an engine control table, in addition to the basic table shown in Table 3 above, as shown in Table 4 below, an exhaust gas reduction table in which retard of ignition timing is excluded from the basic table is shown. It is provided.

[0055]

[Table 4] Then, the control unit 50 switches between the basic table shown in Table 3 and the exhaust gas reduction table shown in Table 4 according to the catalyst temperature indicated by the signal from the catalyst temperature sensor 60, for example. . That is,
When the catalyst temperature is lower than the predetermined value, the control unit 50 sets the mode flag Fm to 0 indicating the normal mode and controls the state of the engine 5 according to the basic table of Table 3. On the other hand, when the catalyst temperature exceeds the predetermined value, the control unit 50 sets the mode flag Fm to 1 indicating the exhaust gas reduction mode and controls the state of the engine 5 according to the exhaust gas reduction table of Table 4. It has become.

On the other hand, the TCS control by the brake control is specifically performed as follows.

That is, the control unit 50 is
When the TCS control condition is satisfied, the first opening / closing valve 26 constituting the brake control system 15 is closed and the second opening / closing valve 27 is opened. Therefore, the operating pressure generated by the pump 21 is supplied to the rear wheel braking pressure lines 29, 30 as braking pressure without passing through the booster 17.

Then, the control unit 50 fits the vehicle body speed Vr and the road surface friction coefficient μ calculated as described above to the map of the brake control slip target reference value in which the vehicle body speed and the road surface friction coefficient are set in advance as parameters. And the corresponding value is the target slip basic value T for brake control.
This target slip basic value T is set as bo
By substituting bo and the brake control target value correction coefficient K2 into the following relational expression (5), the brake control slip target value Tb is finally set.

Tb = Tbo · K2 (5) In that case, the target slip basic value Tbo for brake control
Is preset to be a value larger than the engine control slip target value Te. Further, the target value correction coefficient K2 for brake control is normally set to 1. Therefore, in the normal mode in which the mode flag Fm is set to 0, the brake control slip target value Tb is the engine control slip target value Te.
Will be set to a larger value.

Then, the control unit 50 controls the brake control slip target value Tb and the left and right rear wheels 3, 3.
By substituting the slip value S of No. 4 into the following relational expression (5), the deviation ΔSe of the slip amount S of the left and right rear wheels 3, 4 with respect to the brake control slip target value Tb is calculated, and Substituting the current value ΔSb _(J) and the previous value ΔSb _{(J-1) of the} deviation ΔSb into the following relational expression (7),
The calculation result is defined as the deviation change rate DSb.

ΔSb = S-Te (6) DSb = ΔSb _(J) -Sb _(J-1) (7) Then, the control unit 50 controls the deviation ΔSb.
Then, the deviation change rate DSb is applied to the table shown in Table 5 below, and the corresponding value is set as a control label that represents the brake control amount. Then, according to this control label, the rear wheel braking pressure line 29, The on-off valves 31, 32 on the 30 or the relief valves 33, 34 are duty-controlled.

[0062]

[Table 5] Here, the symbol ZO in Table 5 above indicates the holding of the braking pressure, N indicates the pressure reduction, and P indicates the pressure increase. The subscripts S, M, B of N and P indicate the magnitude of the brake control amount,
S is small, M is medium, and B is large. Therefore, for example, if PB is selected as the control label, the on-off valves 31 and 32 are driven with the maximum control amount, and the braking pressure of the brake devices 13 and 14 for rear wheel braking is rapidly increased. It will be. Also, for example, if NB is selected as the control label, the relief valves 33 and 34 are driven with the maximum control amount, and the brake devices 13 and 1 are driven.
The braking pressure of 4 is suddenly reduced.

In the first embodiment, the control shown in the flowchart of FIG. 2 is performed according to the mode of traction control by engine control.

That is, the control unit 50 is
In step S1, it is determined whether or not the traction flag Ft is set to 1, which indicates that the TCS control is being performed, and if the TCS control is being performed, the process proceeds to step S2, and the mode flag Fm indicates the exhaust gas reduction mode. It is determined whether it is set to 1. When the mode flag Fm is not 1, that is, when it is determined that the mode is the normal mode,
Step S3 is executed to execute normal control.

On the other hand, when the control unit 50 determines in step S2 that the mode flag Fm is set to 1, that is, the exhaust gas reduction mode is set, the automatic transmission 5 is determined in step S4.
Is forcibly upshifted, the engine control target value correction coefficient K1 is set to 1.2 in step S5, and the brake control target value correction coefficient K2 is set to 0.8 in step S6. Therefore, while the engine control slip target value Te set according to the relational expression (1) increases, the brake control slip target value Tb set according to the relational expression (5) decreases.

Next, the operation of the first embodiment will be described.

For example, as shown in FIG. 3, when the maximum slip amount SHi of the rear wheels 3, 4 exceeds the control start threshold value Ss for the first time, the control unit 50 sets the slip flag Fs to 1 and then performs engine control. The TCS control that uses the brake control together is started. At that time, the traction flag Ft indicates that the TCS control is in progress. 1
Is set to.

When the drive wheel speed is higher than the brake control slip target value Tb, the slip amount is controlled by the brake control and the engine control so that the first spin is rapidly reduced. . When the drive wheel speed exceeds the maximum value and then falls below the brake control slip target value Tb, engine control becomes dominant and the drive wheel speed (slip amount) converges to the engine control slip target value Te. The engine output is feedback controlled. In that case, in the normal mode, the basic table shown in Table 3 above is selected as the engine control table, so that the engine 5 has 11 stages of control in which retard of ignition timing and fuel cut are combined. It will be precisely controlled according to the pattern.

Then, when the maximum slip amount SHi becomes lower than the control end threshold value Se, the slip flag Fs is reset to 1, and thereafter the traction flag Ft is set at the time when a predetermined waiting time t elapses. It is reset to 0 and the TCS control ends.

On the other hand, when the catalyst temperature rises above a predetermined value,
The engine control mode may be switched from the normal mode to the exhaust gas reduction mode. In such a case, as shown in FIG. 4, at the time when the mode flag Fm is switched from 0 to 1, the engine control slip target value Te is increased as indicated by the symbol a and the symbol a is indicated by the symbol a. As shown, the brake control slip target value Tb is reduced. Then, the exhaust gas reduction table shown in Table 4 above is selected as the engine control table. In this case, the retardation of the ignition timing is stopped, and the fuel is cut off from the two cylinders even when the control level EL values are "1" and "2". The amount of unburned components in the exhaust gas flowing into 48 will be reduced. As a result, the oxidation reaction of the unburned components in the catalytic converter 48 is suppressed, and the abnormal temperature rise of the converter 48 is prevented.

In this case, since the engine control slip target value Te is increased, the engine 5 is controlled to the torque-up side, and the driver feels a stall due to insufficient drive torque. There is no.

Further, the brake control slip target value Tb
Is reduced, the engine 5 is further controlled to the torque-increasing side by the amount that the drive torque is reduced by the brake control, and it is possible to more reliably prevent the driver from feeling a stall. become.

Moreover, in this embodiment, the gear stage of the automatic transmission 6 is, for example, from the third speed to the fourth speed at the time when the mode flag Fm is set to 1, as shown by the symbol c in FIG.
Since the gear is forcibly upshifted to the high speed, the slip amount of the drive wheels (rear wheels 3, 4) is reduced, and accordingly, the engine 5 is controlled to the torque-up side, which causes the driver to stall. It is possible to more surely prevent feeling.

Next, a second embodiment of the present invention will be described.

In the second embodiment, the control shown in the flow chart of FIG. 5 is performed according to the mode of traction control by engine control.

That is, the control unit 50 is
In step S21, it is determined whether or not the traction flag Ft is set to 1, which indicates that the TCS control is in progress. If the traction flag Ft is in the TCS control, the process proceeds to step S22 and the mode flag Fm indicates the exhaust gas reduction mode. It is determined whether it is set to 1. Mode flag Fm is 1
If not, that is, if it is determined that the normal mode is set, step S23 is executed to execute the normal control.

On the other hand, when the control unit 50 determines in step S22 that the mode flag Fm is set to 1, that is, in the exhaust gas reduction mode, it corrects the engine control target value in step S24. Set 1.2 to the coefficient K1. Therefore, the engine control slip target value Te set according to the relational expression (1) increases.

According to the second embodiment, the following effects can be obtained.

That is, when the catalyst temperature is lower than the predetermined value, the traction control mode by engine control is set to the normal mode, so that the basic table shown in Table 3 above is selected as the engine control table. Therefore, the engine 5 is precisely controlled according to the 11-step control pattern in which the retard of the ignition timing and the fuel cut are combined.

On the other hand, when the catalyst temperature rises above a predetermined value,
When the traction control mode is switched from the normal mode to the exhaust gas reduction mode, the exhaust gas reduction table shown in Table 4 above is selected as the engine control table. Therefore, the retard of the ignition timing is stopped, and the fuel is cut off from the two cylinders even when the value of the control level EL is "1" and "2", so that the fuel flows into the catalytic converter 48 per unit time. As a result, the amount of unburned components in the exhaust gas is reduced, and the abnormal temperature rise of the converter 48 is prevented.

In this case, since the engine control slip target value Te is increased, the engine 5 is controlled to the torque-up side, and the driver feels a stall due to insufficient drive torque. There is no.

Next, a third embodiment of the present invention will be described.

In the third embodiment, the control process of step S24 in the flowchart of FIG. 5 showing the second embodiment is executed.
As shown in the flowchart of FIG. 6, step S24 ′
The difference is that the control process is changed to.

That is, in the third embodiment, when it is determined in step S22 that the mode flag Fm is set to 1, that is, when it is determined that the exhaust gas reduction mode is set, the automatic transmission 6 operates. The gear is forced to be upshifted. Therefore,
The slip amount of the drive wheels (rear wheels 3, 4) is reduced, and the engine 5 is controlled to the torque-up side accordingly, which prevents the driver from feeling stall. Will be.

Next, a fourth embodiment of the present invention will be described.

In the fourth embodiment, the control process of step S24 in the flowchart of FIG.
As shown in the flowchart of FIG. 7, step S24 ″
The difference is that the control process is changed to.

That is, in the fourth embodiment, when it is determined in step S22 that the mode flag Fm is set to 1, that is, when it is determined that the exhaust gas reduction mode is set, the brake control slip target is set. The value Tb will be reduced. As a result, the brake control slip target value Tb set according to the relational expression (5) is reduced, and the engine 5 is controlled to the torque-up side by the amount that the drive torque is reduced by the brake control. As a result, it is possible to prevent the driver from feeling a stall.

Next, a fifth embodiment of the present invention will be described.

In the fifth embodiment, the control shown in the flowchart of FIG. 8 is performed according to the mode of traction control by engine control.

That is, the control unit 50 is
In step S31, it is determined whether or not the traction flag Ft is set to 1, which indicates that the TCS control is being performed, and if the TCS control is being performed, the process proceeds to step S32, and the mode flag Fm indicates the exhaust gas reduction mode. It is determined whether it is set to 1. Mode flag Fm is 1
If not, that is, if it is determined that the normal mode is set, step S33 is executed to execute the normal control.

On the other hand, when the control unit 50 determines in step S32 that the mode flag Fm is set to 1, that is, in the exhaust gas reduction mode, the control gain G of the engine 5 is determined in step S34. Set 2 to. Therefore, the engine control level E calculated according to the above relational expression (4)
L will increase or decrease at high frequencies.

According to the fifth embodiment, the following effects can be obtained.

That is, when the catalyst temperature rises above a predetermined value and the traction control mode is switched from the normal mode to the exhaust gas reduction mode, the exhaust gas reduction table shown in Table 4 above is selected as the engine control table. Will be. Therefore, the retard of the ignition timing is stopped, and the fuel is cut off from the two cylinders even when the value of the control level EL is "1" and "2", so that the fuel flows into the catalytic converter 48 per unit time. As a result, the amount of unburned components in the exhaust gas is reduced, and the abnormal temperature rise of the converter 48 is prevented.

In this case, the engine control level EL increases or decreases at a high frequency, so that the engine output also changes at a high frequency, which avoids fluctuations in wheel speed and improves controllability.

Next, a sixth embodiment of the present invention will be described.

In the sixth embodiment, the control shown in the flowchart of FIG. 9 is performed according to the mode of traction control by engine control.

That is, the control unit 50 is
In step S41, it is determined whether or not the traction flag Ft is set to 1, which indicates that the TCS control is in progress. If the traction flag Ft is in the TCS control, the process proceeds to step S42, and the mode flag Fm indicates the exhaust gas reduction mode. It is determined whether it is set to 1. Mode flag Fm is 1
If not, that is, if it is determined that the normal mode is set, step S43 is executed to execute the normal control.

On the other hand, when the control unit 50 determines in step S42 that the mode flag Fm is set to 1, that is, in the exhaust gas reduction mode, it corrects the engine control target value in step S44. Set 0.8 to the coefficient K1. Therefore, the engine control slip target value Te set according to the relational expression (1) is reduced.

According to the sixth embodiment, the following effects can be obtained.

That is, when the catalyst temperature rises above a predetermined value and the traction control mode is switched from the normal mode to the exhaust gas reduction mode, the exhaust gas reduction table shown in Table 4 above is selected as the engine control table. Will be. Therefore, the retard of the ignition timing is stopped, and the fuel is cut off from the two cylinders even when the value of the control level EL is "1" and "2", so that the fuel flows into the catalytic converter 48 per unit time. As a result, the amount of unburned components in the exhaust gas is reduced, and the abnormal temperature rise of the converter 48 is prevented.

In this case, since the engine control slip target value Te is reduced, the engine 5 is controlled to the torque down side, which further reduces the engine output, and the control Stability will be secured.

[0102]

As described above, according to the first to fourth inventions of the present application, in a traction control device for a vehicle equipped with an engine having a catalytic converter in an exhaust system,
When the exhaust gas reduction mode is executed, control is performed so that the engine control amount becomes a value on the torque-up side compared to the normal mode, so the required drive torque is secured and the driver feels stall. It doesn't feel.

Further, according to the fifth aspect of the present invention, when the exhaust gas reduction mode is executed, the gain of the engine control increases, so that the engine output changes at a high frequency and the fluctuation of the wheel speed is avoided. As a result, the controllability is improved.

Further, according to the sixth and seventh aspects of the present invention, when the exhaust gas reduction mode is executed, control is performed so that the engine control amount becomes a value on the torque down side as compared with the normal mode. Therefore, the engine output is further reduced, and the control stability is ensured.

[Brief description of drawings]

FIG. 1 is a vehicle control system diagram.

FIG. 2 is a flowchart showing a first embodiment of control according to a mode of traction control by engine control.

FIG. 3 is a time chart diagram of TCS control in a normal mode.

FIG. 4 is a time chart of TCS control showing the operation of the first embodiment.

FIG. 5 is a flowchart showing a second embodiment of control according to a mode of traction control by engine control.

FIG. 6 is a flowchart showing a third embodiment of control according to a mode of traction control by engine control.

FIG. 7 is a flowchart showing a fourth embodiment of control according to a mode of traction control by engine control.

FIG. 8 is a flowchart showing a fifth embodiment of control according to a mode of traction control by engine control.

FIG. 9 is a flowchart showing a sixth embodiment of control according to a mode of traction control by engine control.

[Explanation of symbols]

 5 engine 6 automatic transmission 31, 32 on-off valve 33, 34 relief valve 44 fuel injection valve 46 spark plug 47 exhaust passage 48 catalytic converter 50 control unit 51-54 wheel speed sensor 60 catalyst temperature sensor

Claims (7)

[Claims] An exhaust system is equipped with an engine having a catalytic converter for purifying exhaust gas, and traction control means is provided for suppressing an excessive driving force by controlling the engine at least when the drive wheels are excessively slipped. A traction control device for a vehicle, wherein, when the catalytic converter is in a high temperature state, a mode switching means for switching an engine control mode from a normal mode to an exhaust gas reduction mode for reducing exhaust gas, and an exhaust gas reduction mode during execution. A traction control device for a vehicle, comprising: a control unit that performs control such that the control amount of the engine becomes a value on the torque-up side as compared with the normal mode. 2. The traction control device for a vehicle according to claim 1, wherein the control means is configured to increase a target value for engine control when the exhaust gas reduction mode is selected. . 3. The traction control of the vehicle according to claim 1, wherein the control means is configured to upshift the shift speed of the transmission when the exhaust gas reduction mode is selected. apparatus. 4. The traction control means is configured to perform brake control in combination with engine control, and the control means sets a target value for brake control when an exhaust gas reduction mode is selected. The traction control device for a vehicle according to claim 1, wherein the traction control device is configured to be reduced. 5. An engine having an exhaust gas purifying catalytic converter is mounted on an exhaust system, and traction control means for suppressing an excessive driving force by controlling the engine at least when the drive wheels are excessively slipped is provided. A traction control device for a vehicle, wherein, when the catalytic converter is in a high temperature state, a mode switching means for switching an engine control mode from a normal mode to an exhaust gas reduction mode for reducing exhaust gas, and an exhaust gas reduction mode during execution. A traction control device for a vehicle, comprising: a control gain changing means for increasing a gain of engine control as compared with a normal mode. 6. An engine having an exhaust gas purification catalytic converter is mounted on an exhaust system, and traction control means is provided for suppressing an excessive driving force at least by controlling the engine when the drive wheels are excessively slipped. A traction control device for a vehicle, wherein, when the catalytic converter is in a high temperature state, a mode switching means for switching an engine control mode from a normal mode to an exhaust gas reduction mode for reducing exhaust gas, and an exhaust gas reduction mode during execution. A traction control device for a vehicle, further comprising: a control unit that performs control so that the control amount of the engine becomes a value on the torque down side as compared with the normal mode. 7. The traction control device for a vehicle according to claim 6, wherein the control means is configured to reduce a target value for engine control when the exhaust gas reduction mode is selected. .