JPH08238958A - Vehicle driving force control device - Google Patents

Abstract

PURPOSE: To reduce the superheating period of catalyst temperature so as to prevent degradation by shifting up a speed change stage to a high speed stage in the case of fuel cut-off being performed at the specified value or more of engine rotation, and increasing the fuel quantity while suppressing up-shift in the case of judging the low temperature time. CONSTITUTION: An engine control circuit 60 normally controls high voltage generating timing (ignition timing) from an ignition coil 73 to a spark plug 69, the valve open time (fuel injection quantity) of an injector 62, and the like on the basis of detection signals from sensors 49, 76, 67, 65, 68, 74, 63, 74, 77, and executes the delay control of ignition timing and fuel cut-off control on the basis of an engine torque control execution signal from an acceleration slip control circuit 40. The engine control circuit 60 also outputs information such as cylinder cut-off authorization to the acceleration slip control circuit 40 while inputting an engine torque reducing signal and outputs commands of demanding up-shift, down-shift and the like to make a transmission 75 perform speed change.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle driving force control device for performing traction control by cutting fuel, and more particularly to a vehicle driving force control device for preventing overheating of a catalyst device during traction control.

[0002]

2. Description of the Related Art Conventionally, when an acceleration slip occurs at the time of starting or the like, the fuel supply to some of the plurality of cylinders of a multi-cylinder engine is cut to suppress the slip of the drive wheels. A vehicle driving force control device that performs traction control is known.

In this type of control device, unburned fuel is discharged from the cylinders that have not undergone fuel cut, while intake air containing oxygen is discharged as hot exhaust gas from the cylinders that have undergone fuel cut. Therefore, in the exhaust gas purifying catalyst device provided in the exhaust system, the unburned fuel and oxygen are mixed and burned, so that the catalyst temperature rises and the performance of the catalyst deteriorates.

As a countermeasure against this, when the traction control is performed by cutting the fuel, the gear stage of the automatic transmission is shifted up so that the engine speed does not become a high rotation speed. There is proposed a technique for suppressing the combustion of the catalyst and preventing the performance deterioration of the catalyst (see Japanese Patent Laid-Open No. 4-92729).

In addition to this, generally, in the case of a gasoline engine, there is known a so-called fuel amount increasing technique at a low temperature, in which the fuel supply amount is increased when the engine temperature is low to ensure drivability.

[0006]

However, in the case of increasing the fuel amount at the low temperature, if a fuel cut is performed in a part of the cylinders in order to perform the traction control, a large amount of unburned fuel (increased amount) will be generated. Since oxygen and oxygen are combusted in the catalyst, the catalyst temperature rises significantly, which causes a problem of increased catalyst deterioration.

At this time, if the control by the above-mentioned shift-up is performed for the purpose of preventing the catalyst temperature from rising, the engine speed decreases, so that the temperature rising speed of the engine is suppressed. If the temperature rise of the engine becomes slow, the time until warm-up becomes longer, that is, the period for increasing the fuel amount at low temperature becomes longer, so that the period during which the increased unburned fuel and oxygen are burned in the catalyst is increased. As a result, there arises a problem that the catalyst temperature continues to be overheated for a long time and the catalyst performance is greatly deteriorated.

Further, if the control by the shift-up is performed, the engine torque required to obtain the same driving force becomes large, so that the frequency of fuel cut becomes small (= the number of cylinders supplying fuel increases). When the frequency of this fuel cut is reduced, as shown in FIG. 15, the catalyst temperature tends to increase, and this tendency is particularly remarkable at low temperature after warming up. Therefore, also from this point, the control for upshifting at a low temperature deteriorates the catalyst performance and is not preferable.

The present invention has been made to solve the above-mentioned problems, and even when traction control is performed by cutting the fuel at a low temperature, a vehicle drive capable of reducing the catalyst temperature overheating period and preventing deterioration of the catalyst performance. An object is to provide a force control device.

[0010]

As shown in FIG. 1, the invention according to claim 1 for attaining the above-mentioned object, according to an operating state of a multi-cylinder engine having an exhaust purification catalyst in an exhaust system, In a vehicle driving force control device for controlling an injection amount and a shift position of a transmission, an engine rotation speed detecting means for detecting the rotation speed of the engine and a fuel supply for each cylinder are cut according to a state of acceleration slip of the vehicle. And the fuel cut control means for controlling the engine speed, the engine speed detected by the engine speed detection means is equal to or higher than a predetermined value, and the fuel cut control means is performing the fuel cut, the shift stage of the transmission. Shift-up control means for shifting up to a high speed stage, temperature state determination means for determining whether the engine is warmed up or low temperature, and the temperature state determination means determines low temperature In the case of low temperature, the low temperature fuel increase control means for increasing the fuel amount, and in the case of low temperature by the temperature state determining means, the upshift suppressing means for suppressing the upshift by the upshift control means. A gist of a vehicle driving force control device is characterized by including:

A second aspect of the present invention provides the vehicle driving force control device according to the first aspect, wherein the shift-up suppressing means prohibits shift-up. A third aspect of the invention provides the vehicle driving force control device according to the first or second aspect, wherein the shift-up suppressing unit holds a shift position.

A fourth aspect of the present invention provides the vehicle driving force control device according to the first or second aspect, characterized in that the upshift suppressing means performs downshifting.
A fifth aspect of the present invention is the vehicle driving force control device according to any one of the first to fourth aspects, characterized in that the shift-up suppressing unit changes a shift timing so that it is difficult to shift up. To do.

According to a sixth aspect of the invention, the vehicle driving force control apparatus according to any one of the first to fifth aspects is characterized in that the shift-up suppressing means changes the shift timing so that shift-down can be easily performed. Is the gist.

The invention of claim 7 permits the control by the shift-up suppressing means when the engine speed falls below a predetermined judgment value.
The gist is the vehicle driving force control device according to any one of to.

[0015]

According to the invention of claim 1, when the engine speed detected by the engine speed detecting means is equal to or higher than a predetermined value and the fuel cut control means is performing the fuel cut, When the shift-up control means shifts up the shift stage of the transmission to a high-speed stage and the temperature state determination means determines that the engine is at a low temperature, the low temperature fuel increase control means increases the amount of fuel and When the temperature state determining unit determines that the temperature is low, the shift-up suppressing unit suppresses the shift-up by the shift-up controlling unit.

That is, when the fuel is cut at the time of acceleration slip and the fuel amount is increased at a low temperature, the engine temperature rises when the engine speed is reduced by upshifting as in the conventional case for the purpose of reducing the catalyst temperature. The speed decreases and, conversely, the catalyst temperature superheating period (increased by increasing the fuel amount at low temperature) becomes longer. Therefore, in the present invention, in such a low temperature of the engine, the shift up is suppressed to suppress the decrease in the engine speed.

As a result, for example, the rate of temperature rise of the engine does not decrease, the warm-up does not delay, and the period of fuel increase at low temperature does not increase. As a result, the period during which the catalyst temperature is overheated does not increase, so that the remarkable effect of preventing the deterioration of the catalyst performance can be achieved. Incidentally, as the temperature state determination means,
For example, determination based on the detected cooling water temperature can be adopted.
Further, in both the low temperature fuel increase control means and the shift up control means, indirect determination may be adopted instead of directly determining the cooling water temperature. For example, the upshift control means may be executed based on a flag or the like indicating execution of the low temperature fuel increase control means.

According to the second aspect of the invention, means for inhibiting the shift-up can be adopted as the shift-up suppressing means.
In that case, it is possible to reliably prevent the upshift and prevent the engine speed from decreasing. Therefore, it is possible to preferably prevent the catalyst performance from decreasing. In the invention of claim 3, as the shift-up suppressing means, a means for holding the shift position when the condition for executing the shift-up suppressing means is satisfied can be adopted. In that case, not only the shift-up but also the shift-down is prohibited, so that an appropriate gear shift position can be secured by simple control, and the reduction of the catalyst ability can be preferably prevented.

In the fourth aspect of the invention, means for downshifting can be adopted as the upshift suppressing means. In that case, the engine speed can be controlled to increase,
It is possible to accelerate the warm-up of the engine more effectively than the control that simply prohibits the shift-up, and it is possible to preferably prevent the deterioration of the catalyst capacity. In other words, since the engine temperature increase rate increases, warm-up is accelerated, and the period of fuel increase at low temperatures can be shortened, thereby shortening the period of catalyst temperature overheating and suitably preventing deterioration of catalyst capacity. it can.

According to the fifth aspect of the present invention, as the shift-up suppressing means, means for changing the shift timing so that it is difficult to shift up can be adopted. For example, the shift timing can be changed by changing a map or the like that sets a shift line or the like for upshifting.

In the sixth aspect of the invention, as the shift-up suppressing means, a means for changing the shift timing so as to facilitate the shift-down can be adopted. For example, the shift timing can be changed by changing a map or the like that sets a shift line or the like for downshifting. As a result, the temperature of the engine can be raised promptly, so that the reduction of the catalytic ability can be prevented appropriately.

According to the seventh aspect of the invention, when the engine speed falls below a predetermined judgment value, the control by the shift-up suppressing means is permitted. Therefore, it is possible to more reliably cope with the engine warm-up difficult state and the catalyst performance. Can be suitably prevented. Further, when the engine speed is high, the shift-up is not suppressed, so that the engine speed can be adjusted to a preferable speed by control such as normal shift-up.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 2 is a schematic configuration diagram showing the overall configuration of a rear-wheel drive vehicle equipped with the vehicle driving force control device of this embodiment.

The vehicle driving force control system of the present embodiment has a structure for performing traction control for suppressing acceleration slip when an acceleration slip occurs in the vehicle, a structure for increasing fuel at low temperature, and an automatic transmission according to operating conditions. And a configuration for performing shift control. Among them, as a configuration for performing traction control, an acceleration slip control circuit 40 that drives a braking device for driving wheels to directly suppress rotation of the driving wheels to perform brake control, and an instruction from the acceleration slip control circuit 40 An engine control circuit 60 for controlling the engine by suppressing the output torque of the internal combustion engine (engine) 1 by adjusting the ignition timing and adjusting the fuel supply amount by cutting the fuel. Further, as a configuration for performing shift control, a shift control circuit 78 for adjusting the shift position based on an instruction from the engine control circuit 60 is provided. This will be described in detail below.

(1) First, a hardware configuration for performing brake control will be described with reference to FIG. As shown in FIG. 2, the vehicle equipped with the engine 1 includes wheel cylinders 5 and 6 for left and right front wheels 3 and 4 that are idle wheels, and wheel cylinders 9 and 10 for left and right rear wheels 7 and 8 that are drive wheels. Between the wheel cylinders 5, 6, 9 and 10 and the brake master cylinder 2, a hydraulic power source 11, an anti-skid control hydraulic circuit 12 and an acceleration slip control hydraulic circuit 13 are provided.

First hydraulic chamber 2 of brake master cylinder 2
Displacement control valves 14 and 15 for left and right front wheel anti-skid control are provided in the brake hydraulic circuits from a to the wheel cylinders 5 and 6 of the left and right front wheels 3 and 4. Further, from the second hydraulic chamber 2b of the brake master cylinder 2 to the left and right rear wheels 7,
In the brake hydraulic circuit leading to the wheel cylinders 9 and 10 of No. 8, proportional valve 16, rear wheel anti-skid control capacity control valve 17, first solenoid valve 18 and check valve 19 arranged in parallel, acceleration slip control. A capacity control valve 20 is provided.

Next, the structure of the acceleration slip control circuit 40 for executing this brake control will be described with reference to FIG. As shown in FIG. 3, the acceleration slip control circuit 40
Is a well-known CPU 40a, ROM 40b, RAM 40
c, a backup RAM 40d, etc., is configured as a logical operation circuit, and is connected to an input port 40f and an output port 40g via a common bus 40e.

The input port 40f has a pedal switch 44 which outputs an ON / OFF signal depending on whether or not the brake pedal 50 (FIG. 2) is operated, and a left front wheel rotation speed sensor 45 which detects the rotation speed of the left front wheel 3. , A right front wheel speed sensor 46 for detecting the rotation speed of the right front wheel 4, a rear wheel rotation speed sensor 47 for detecting the rotation speeds of the left and right rear wheels, an engine speed sensor 49 for detecting the rotation speed of the engine 1, and an accelerator pedal 50. The throttle opening degree sensor 52 for detecting the opening degree of the throttle valve 51 opened and closed by the operation is connected, and the detection signal from each sensor is input. on the other hand,
To the output port 40g, via a drive circuit not shown,
The first to third solenoid valves 18, 21, 22 and the pump driving motor 26 are connected and a control signal is sent to each actuator.

Thus, the acceleration slip states of the left and right rear wheels are detected based on the detection signals from the respective sensors, and the brake control of the rear wheels is executed according to the state of the acceleration slip.
An engine control circuit 60 is connected to the acceleration slip control circuit 40, and when an acceleration slip occurs,
The acceleration slip control circuit 40 outputs an engine torque control execution signal to the engine control circuit 60 so that engine torque control for controlling the ignition timing and the fuel injection amount can be executed.

(2) Next, a hardware configuration for controlling the engine will be described with reference to FIG. An intake pipe 61 of the engine 1 is provided with an air flow meter 76 for measuring the intake air amount, a throttle valve 51, and an injector 62 for injecting fuel into each cylinder from the upstream side. Oxygen sensor 6 for detecting oxygen concentration
5. A three-way catalyst 66 for purifying exhaust gas and a catalyst temperature sensor 63 for detecting the temperature of the catalyst 66 are arranged. Further, the engine 1 is provided with a temperature sensor 67 for detecting the temperature of cooling water, a knock sensor 68 for detecting knocking, and an ignition plug 69 for igniting an air-fuel mixture for each cylinder. The ignition plug 69 has a distributor. An ignition coil 73 that supplies a high-voltage pulse is connected via 71. A crank angle sensor 74 for detecting the rotation of the crank angle and the engine speed sensor 49 are attached to the distorter 71.

Further, the transmission 75 connected to the drive shaft of the engine 1 is provided with a shift control circuit 78 for executing shift control such as shift up and shift down based on a control signal from the engine control circuit 60. ing. It should be noted that the transmission 75 is provided with a shift position detecting switch 77 in order to detect the shift speed.

Next, the engine control circuit 60 for controlling the engine will be described with reference to FIG. As shown in FIG. 3, the engine control circuit 60, like the acceleration slip control circuit 40, has a well-known CPU 60a and ROM 60.
b, the RAM 60c, the backup RAM 60d, and the like are configured as a logical operation circuit, and are connected to the input port 60f and the output port 60g via the common bus 60e.

At the input port 60f, an engine speed sensor 49, an air flow meter 76, a water temperature sensor 67,
Oxygen sensor 65, knock sensor 68, crank angle sensor 74, catalyst temperature sensor 63, shift position detection switch 7
7 is connected, and the detection signal from each sensor is input.
On the other hand, an ignition coil 73 and an injector 62 are connected to the output port 60g via a drive circuit (not shown),
A control signal is sent to each actuator. The shift control circuit 78 is connected to the output port 60g, and a control signal for driving the transmission 75 is sent to the shift control circuit 78.

That is, the engine control circuit 60 normally operates the ignition coil 7 based on the detection signals from the respective sensors.
3 controls the timing at which a high voltage is generated from 3 to the spark plug 69 (ie, ignition timing), the valve opening time of the injector 62 (fuel injection amount), and the like. And when an acceleration slip occurs,
Based on the engine torque control execution signal from the acceleration slip control circuit 40, ignition timing retard control and fuel cut control are executed. In addition, the acceleration slip control circuit 40
In response to, output information such as cut-off cylinder permission, and input an engine torque reduction signal. Further, it outputs a command such as a shift-up request or a shift-down request to the transmission control circuit 78 in order to cause the transmission 75 to shift.

(3) Next, the brake control process will be described. Note that this control process is executed by the acceleration slip control circuit 40. When the process is started, as shown in the flowchart of FIG. 4, first, at step 100, the brake control set when the execution of the brake control is started. It is determined whether the execution flag FB is in the reset state, that is, whether the brake control is not currently executed. If an affirmative judgment is made here, the routine proceeds to step 110, while if a negative judgment is made, the routine proceeds to step 140.

In step 110, since the brake control is not executed, it is determined whether or not the execution condition of the brake control is satisfied depending on whether or not the drive wheel speed VR becomes equal to or more than the control reference value VB for executing the brake control described later. To judge. Then, if the driving wheel speed VR is not equal to or higher than the control reference value VB and the execution condition of the brake control is not satisfied, this processing is temporarily terminated, and if not, the process proceeds to step 120.

At step 120, since the brake control execution condition is satisfied, the brake control execution flag FB indicating the execution of the brake control is set, then the routine proceeds to step 140, and the brake control is executed as shown in Table 1 below. To do.

[0038]

[Table 1]

Where dV is the rotational acceleration of the drive wheel, G1
Is a positive reference acceleration, G2 is a negative reference acceleration, and FU
Represents pressure increasing in the wheel cylinders 9 and 10 for the left and right rear wheels, SU gradually increasing pressure, FD decreasing pressure, and SD gradually decreasing pressure. That is, in step 140, the driving wheel acceleration dV is calculated based on the driving wheel speed VR, and the hydraulic pressure is increased when the driving wheel speed VR is VB or higher and the driving wheel acceleration dV is G2 or higher, and is decreased otherwise. As a result, the speed is quickly reduced by the brake.

In the following step 150, the brake control is performed depending on whether the integrated value ΣTP of the brake hydraulic pressure increase control time TP is below a value obtained by multiplying the integrated value ΣTDP of the hydraulic pressure decrease control time TDP by the correction coefficient Kp. It is determined whether or not the brake oil pressure has become zero. If it is determined that the brake hydraulic pressure has become 0, step 160
At this point, it is assumed that the brake control is completed, the brake control execution flag FB is reset, and then the present process is completed.
If not, this processing is ended as it is.

As described above, the brake control is started when the drive wheel speed VR becomes equal to or higher than the control reference value VB, and thereafter, until the brake hydraulic pressure becomes 0, the drive wheel speed VR is reached.
And is repeatedly executed according to the driving wheel acceleration dV. (4) Next, the engine control process will be described.
The control process is executed on the engine control circuit 60 side based on the signal from the acceleration slip control circuit 40.

A) First, the engine torque reduction control performed according to the control reference value VS and the like will be described. As shown in the flowchart of FIG. 5, first in step 200,
Detection signals are input from the left and right front wheel and rear wheel rotation speed sensors 45, 46, 47 to calculate the vehicle body speed VF and the driving wheel speed VR. The vehicle body speed VF is calculated by multiplying the average output value of the left and right front wheel rotation speed sensors 45, 46 or the larger value by the perimeter of the front wheel, and the drive wheel speed VR is the output of the rear wheel rotation speed sensor 47. Is calculated by multiplying by the perimeter of the front wheel.

In the following step 205, the control reference value VS for the engine control (that is, the engine torque reduction control) is calculated from the calculated vehicle speed VF by using the following equations (1) and (2), and the above-mentioned. A control reference value VB for brake control is calculated. VS = VF · a1 (1) VB = VF · a2 (2) Here, a1 and a2 are both constants of 1 or more (for example, a1 is 1.12 to 1.20), and a1 <a2. .

In the following step 210, it is determined whether or not the cut-off cylinder is permitted. Here, if the state is prohibited, step 215
Then, the value of VS is substituted into the control reference value VB, and if not, the process proceeds to step 220. That is, the brake control reference value VB is changed by the cut-off cylinder permission signal.

At step 220, whether or not the engine torque control execution flag FS set at the start of the engine torque reduction control is reset in the process described later,
That is, it is determined whether or not the engine torque control is currently being executed. Here, if it is determined that the engine torque control is not executed, the process proceeds to step 225, and if not, the process proceeds to step 265.

In step 225, the throttle valve 5
1 is not in the fully closed state, and whether the driving wheel speed VR is equal to or higher than the control reference value VS described above determines whether or not the execution condition of the acceleration slip control is satisfied.
Here, if it is determined that the execution condition of the acceleration slip control is not satisfied, this process is once terminated, and if not, the process proceeds to step 230.

In step 230, the flag Fo is shown to indicate that the conditions for executing the acceleration slip control are satisfied.
Set to 1. In a succeeding step 235, it is judged whether or not a predetermined time (for example, 8 msec) has elapsed after the control execution condition is satisfied in order to surely determine the occurrence of the acceleration slip. Here, if it is determined that the predetermined time has not elapsed, this process is once terminated, and if not, the process proceeds to step 240.

In step 240, since the predetermined time has elapsed after the control execution condition is satisfied, the engine torque control execution flag FS is set to indicate the start of the engine torque reduction control. In the following step 245, since the output torque, the engine speed NE, and the throttle opening θ have the relationship shown in FIG. 6 (b), based on the engine speed NE and the throttle opening θ, FIG. ), The correction coefficient K of the engine torque reduction rate TR is interpolated.

In the following step 250, the brake control execution flag FB set during the execution of the above-mentioned brake control.
Determines whether or not it is in the reset state. If the brake control execution flag FB is in the reset state and the brake control is not executed, the process proceeds to step 255.

In step 255, the engine torque reduction rate TR is calculated by the following equation (3). TR = K (α · ΔV + β · dV) (3) In the formula (3), α is a proportional gain, β is a differential gain, and ΔV is a control reference value VS which is a target driving wheel speed. The difference (VS-VR) from the driving wheel speed VR, dV, is the time differential value thereof.

That is, in this way, when the brake control is not performed, the engine control is executed so that the drive wheel speed VS approaches the reference control value VS. on the other hand,
When the brake control execution flag FB is set and the brake control is being executed, the engine torque reduction rate TR is decreased by a predetermined value c in step 260. This is to prevent the brake control and the output torque control from interfering with each other by suppressing the engine torque reduction speed to the predetermined speed c when the brake control is executed.

When the engine torque reduction rate TR is set in this way, this process is once terminated. Next, when it is determined in step 220 that the engine torque control execution flag FS is in the set state, that is,
If the engine torque control has already been executed, the routine proceeds to step 265, where it is determined whether or not the post-control start flag Fo has been set. If the flag Fo has not been set, then the routine proceeds to step 245. To do.

On the other hand, if the flag Fo is set and the throttle opening is once fully closed after the start of control, the routine proceeds to step 270, whereafter it is judged whether or not the throttle valve 51 is opened. And the throttle valve 5
If 1 is open, the routine proceeds to step 245, where engine torque reduction rate calculation processing is executed, while if fully closed, it is determined that acceleration slip will no longer occur on the drive wheels, After resetting the flags FS and Fo in step 275 and step 280, this processing is once terminated.

B) Next, processing such as fuel injection control will be described. First, basic fuel injection control will be described. Here, the fuel injection amount Ti is calculated as follows. That is, based on the detected intake air amount Qa and the engine speed NE, after calculating the basic injection amount Tp from the following equation (4), Tp = K · Qa / NE, where K: a constant (4) The fuel injection amount Ti is calculated by correcting the basic injection amount Tp based on the cooling water temperature, the oxygen temperature in the exhaust gas, and the like as shown in (5) below.

Ti = Tp × (1 + KTW + KAS + KAI + KACC + KDEC) × KFC + TB (5) where KTW: water temperature increase correction coefficient KAS: start and start increase correction coefficient KAI: idle increase increase correction coefficient KACC: acceleration correction coefficient KDEC: deceleration correction coefficient KFC: Fuel cut correction coefficient TB: Torque reduction coefficient Then, a pulse signal corresponding to the calculated fuel injection amount is output to the injector 62 to perform fuel injection control.

Next, an injection control routine executed using the fuel injection amount Ti will be described with reference to the flowchart of FIG. This routine is executed at the time of an interrupt generated by comparing a timer and a register (not shown), and is executed in synchronization with the intake stroke of each cylinder.

As shown in FIG. 7, in step 500, it is determined whether or not a fuel cut request for deceleration, maximum speed, prevention of overspeed, etc. has occurred. If an affirmative determination is made here, the routine proceeds to step 520. If negative determination is made, step 53
Go to 0. In step 530, the counter Cinj2 for determining the cylinder for which the fuel cut is performed using the map of FIG.
Is converted into the cylinder-by-cylinder F / C execution value FCLB.

In the following step 535, the F / C required cylinder number FC is calculated based on the engine torque reduction rate TR calculated in step 255 or 260 by the following equation (6).
Calculate L. FCL = 12 × TR / 100 (6) In the following step 540, it is determined whether or not the F / C required cylinder number FCL is equal to or more than the cylinder-specific F / C execution value FCLB. If an affirmative determination is made here, steps 550 to 580 are bypassed, and at step 520, an F / C frequency counter CFC # for each cylinder (# means cylinder number.
Value is used).

On the other hand, if a negative decision is made, step 550
At the CFC # to F / C using the map of FIG.
The correction amount TFC is calculated. In the following step 560, C
FC # is cleared, and in the subsequent step 570, the battery voltage correction amounts TB and TFC are added to Ti to calculate the final injection time Tinj. In the following step 580, the injection start command is sent to the injector 62, and at the same time, a value obtained by adding Tinj to the current time of the timer is set in the injection control register, and at that time, the injection ends by the hardware logic.

Incidentally, in step 500 or 540, Yes
In the case of, the injection is stopped because it bypasses step 580. In the following step 590, the time to enter this routine next is calculated and set in the injection start timing register. This injection start timing is calculated by the following equation (7).

[0061]

[Equation 1]

However, the last 2 ms of the equation is the injector 62
Of the cylinder defrosting counter Cin
Increment j in the range of 1-6. In the following steps 630 to 650, the cylinder discrimination counter Cinj2 for reducing cylinders is used.
Is incremented in the range of 1 to 12, and this process is once terminated.

(5) Next, the shift control process for controlling the shift position, which is the main part of this embodiment, will be described in detail. The shift control process is executed by the engine control circuit 60 and the shift control circuit 78 (based on the control signal from the engine control circuit 60) as described later.

A) First, the shift control process performed by the engine control circuit 60 will be described with reference to the flowchart of FIG. 9. As shown in FIG. 9, at step 700, the above-mentioned brake control, engine control, etc. are executed. It is determined whether or not traction control for adjusting the acceleration slip is being executed.
Here, if it is determined that the traction control is not being executed, a normal signal is output in step 710, and the present processing is ended.

On the other hand, when the traction control is being executed,
At step 720, whether the cooling water temperature is below 5 ° C.,
That is, it is determined whether or not the engine 1 is in a low temperature state, that is, a state in which so-called fuel increase at a low temperature is performed. If it is determined that the temperature is low, at step 730,
Whether or not the engine speed NE is below 5000 rpm,
That is, it is determined whether the engine 1 is at high rotation speed, and if it is high rotation, it is not necessary to control to the high rotation side. Therefore, the routine proceeds to step 710 in order to perform the normal gear shifting operation, and if not high rotation Go to step 740.

In step 740, since the traction control is being executed and the engine speed NE is not high at low temperature, a shift hold command for maintaining the current shift position is output, and this processing is temporarily terminated. That is, here, the fuel cut is executed by the traction control, the fuel amount is increased at the low temperature, and the engine speed NE is increased.
When the engine speed is not high, the shift-up is prohibited and the current shift position is maintained to prevent the engine speed NE from decreasing due to the shift-up. As a result, the temperature rise of the engine 1 is accelerated, the period for increasing the fuel amount at low temperature is shortened, and the catalyst temperature overheating period is shortened.

On the other hand, when it is determined in step 720 that the water temperature is high, it is determined in step 750 whether the engine speed NE is 4000 rpm or more.
If the engine speed NE is lower than this, the routine proceeds to step 710, while if it is high, the routine proceeds to step 76.
Go to 0. The reason why the engine speed NE in step 750 is different from the determination value of the engine speed NE in step 730 is to prevent hunting.

In step 760, the traction control is being executed, but the low temperature increase is not executed because the temperature is not low and the engine speed NE is high. Therefore, a normal upshift command is output. , This process is once ended. That is, shift-up is performed in order to reduce the engine speed NE for the purpose of reducing the catalyst temperature.

B) Next, the shift control performed by the shift control circuit 78 will be described with reference to the flow chart of FIG. 10 and the shift position characteristic diagram of FIG. Note that FIG. 10 shows a control routine executed when the shift lever is in the traveling range (D range).

As shown in FIG. 10, in step 800,
It is determined whether or not the signal is the normal signal output in step 710. If an affirmative decision is made here, step 85 which will be described later.
On the other hand, if the determination is negative, the process proceeds to step 810. At step 810, the engine speed NE is 400.
It is determined whether the speed is equal to or lower than rpm, and in the following step 820,
It is determined whether the engine speed NE is 6000 rpm or more. If each condition is satisfied, the process proceeds to step 850, and if not, the process proceeds to step 830. Here, the reason why the engine speed NE is determined is to prevent engine stall due to excessive reduction of the engine speed NE and to prevent excessive rotation.

In step 830, the above step 740 is executed.
It is determined whether or not the gear shift hold command is output at step 970. If a positive determination is made here, in step 970, in order to maintain the current gear shift position in response to the gear shift hold command,
A process for maintaining the state of the solenoid for setting a gear shift state (not shown) is performed, and the present process is temporarily terminated.

On the other hand, if it is not the shift hold command,
In step 840, it is determined whether or not the shift-up command is output in step 760. If a negative determination is made here, the process proceeds to step 850, and if an affirmative determination is made, the process proceeds to step 860. In step 860, it is determined whether the variable SFT indicating the shift position is less than 4. Incidentally, S
In the FT, 1 to 4 indicate the 1st to 4th speeds, respectively. If an affirmative decision is made here, the routine proceeds to step 570. On the other hand, if the result of the judgment is negative, the current gear position is the fourth gear and it is not possible to shift up any further.
In order to maintain the current shift position, the process for maintaining the state of the solenoid is performed, and the present process is temporarily terminated.

In step 570, it is determined whether or not the time counter CUP for upshifting exceeds 3 sec, that is, whether or not 3 seconds have elapsed since the previous upshifting was performed. This determination is to prevent frequent upshifts, and the time counter CUP is a separate routine.
It is incremented to a predetermined maximum value since the previous shift-up was executed. If an affirmative judgment is made here, the routine proceeds to step 880, whereas if a negative judgment is made, the above-mentioned step 97 is executed.
Go to 0.

In step 880, shift up is performed, and in the following step 890, the shift up time counter CUP is cleared. In the following step 970,
The state of the solenoid is set in order to drive the transmission 75 so that the changed gear position is reached, and the present process is once terminated.

On the other hand, in step 850, when it is judged that the shift is not up, step SF is executed.
It is determined whether T exceeds 1. If an affirmative judgment is made here, the routine proceeds to step 900, while if a negative judgment is made, the routine proceeds to step 940. In step 900, since SFT is 2 or more and there is room for downshifting, the variable THDW for determining downshifting is determined from the variable SPD indicating the vehicle speed and the variable SFT indicating the shift position, as shown in the characteristic diagram of FIG. Calculated from

In FIG. 11, the second speed → first speed, the third speed → second speed, the fourth speed → third speed, the first speed → second speed, the second speed →
The third speed is a characteristic line used for determining the shift from the third speed to the fourth speed. Therefore, for example, SPD = 80 km / h and SFT =
If it is 3 (= 3rd speed), using the characteristic line of 80 km
Since the throttle opening at the point of / h is 65%, THD
W = 0.65.

In the following step 910, it is determined whether or not the variable TH representing the throttle opening exceeds the THDW. If an affirmative determination is made here, the process proceeds to step 915, and if a negative determination is made, the process proceeds to step 940. . Step 9
In 15, the shift down time counter CDW is 3 seconds.
It is determined whether or not ec is exceeded, that is, whether or not 3 seconds have elapsed since the previous shift down was performed. Note that this determination is to prevent frequent downshifts, and the time counter CDW is incremented to a predetermined maximum value since the previous downshift was executed in another routine.
If an affirmative judgment is made here, the routine proceeds to step 920, whereas if a negative judgment is made, the routine proceeds to step 970.

In step 920, downshifting is executed, and in subsequent step 930, the downshifting time counter CDW is cleared. In the following step 970,
The state of the solenoid is set in order to drive the transmission 75 so that the changed gear position is reached, and the present process is once terminated.

On the other hand, in step 940, the variable SF
Since T is 1 or TH ≦ THDW, the variable SFT is 4
It is determined whether or not it is less than, that is, whether or not it is the uppermost stage. If an affirmative determination is made here, the process proceeds to step 950, and if a negative determination is made, the process proceeds to step 970.

In step 950, the variable THUP for determining the upshift is calculated based on the variables SPD and SFT from the characteristic diagram of FIG. In the following step 960, it is determined whether or not TH is less than THUP. If an affirmative determination is made here, the operation proceeds to step 880 and thereafter to perform an upshift process, while if a negative determination is made, the operation proceeds to step 970. , This process is once ended.

As described above in detail, in the present embodiment, the shift-up is prohibited when it is determined that the engine is in the low temperature state and the engine speed NE is lower than the predetermined value during the execution of the traction control by the fuel cut. Then, processing for holding the shift position is performed. Therefore, the engine speed NE does not decrease when the temperature is low, and the temperature of the engine 1 rises faster. Therefore, even if the fuel amount is increased at the low temperature, the period for increasing the fuel amount at the low temperature does not become long, so that the catalyst temperature overheating period is shortened and the deterioration of the catalyst performance can be prevented. Play.

The correction coefficient (water temperature increase correction coefficient KTW) for increasing the quantity at low temperature is a coefficient F set according to the cooling water temperature and the engine speed NE as shown in the following equation (8).
It is determined by W and FN. KTW = FW × FN (8) As shown in FIG. 12, FW and FN have the property of becoming larger as the cooling water temperature and the engine speed NE become smaller, but when the engine speed NE is high, Since the air flow velocity is high, the water temperature increase correction coefficient KTW (which is the correction for the atomization amount) can be set low. That is, by preventing the engine speed NE from decreasing by prohibiting the shift-up, it is possible to reduce the increase amount at low temperature, and also from that point, it is possible to reduce the catalyst temperature overheating period.

(6) Next, an experimental example conducted to confirm the effect of this embodiment will be described with reference to FIG. In this experiment, the catalyst temperature, the cooling water temperature, the engine speed, the gear shift position, and the speed when the vehicle accelerates to 120 km / h immediately after the engine starts and then decelerates → re-accelerates → steady running on the snow-covered road surface Was measured with the progress of. The results are shown in FIG. 13, where (a) is this example and (b) is a comparative example (conventional example).

As is apparent from FIG. 13, in the conventional example, the gear is upshifted to the third speed while accelerating to 120 km / h, but in the present embodiment, it is upshifted only to the second speed. As a result, the engine speed can be kept high, the cooling water temperature rises quickly, and the water temperature increase correction coefficient KTW is also low, so that the catalyst temperature overheating period can be reduced.

(Second Embodiment) Next, a second embodiment will be described. In this embodiment, the hardware configuration is the same as that of the first embodiment and the control is also the same. Therefore, only different points will be described with reference to FIG. A description will be given based on the flowchart.

In the present embodiment, as shown in FIG. 14, in step 1000, it is determined whether or not it is a normal signal, and in the following step 1010, it is determined whether or not the engine speed is 400 rpm or less, and the following step 1020. Then, it is determined whether the engine speed is 6000 rpm or more. If each condition is satisfied, the process proceeds to step 1050, and if not, the process proceeds to step 1030.

In step 1030, it is determined whether or not the gear shift hold command is received. If an affirmative determination is made in step 1030, step 1
At 190, a process for maintaining the state of the solenoid is performed in response to the shift hold command, and the present process is temporarily terminated. On the other hand, if it is not the shift hold command, it is determined in step 1040 whether it is a shift up command. If a negative determination is made here, the process proceeds to step 1050, and if an affirmative determination is made, the process proceeds to step 1060.

In step 1050, the value of the variable TH indicating the throttle opening is input to the variable THC, and step 1
Proceed to 070. On the other hand, in step 1060, since the shift-up command signal is input, the value obtained by dividing TH by 4 is input to the variable THC, and the process similarly proceeds to step 1070. Here, TH / 4 = THC is set by setting the throttle opening used for shifting to the actual 1/4,
This is to encourage shift up. In addition to this, TH
Even if C is set to a low opening (for example, 5%), the same effect can be obtained.

In step 1070, it is determined whether the variable SFT exceeds 1. If an affirmative decision is made here, the operation proceeds to step 1080, whereas if a negative decision is made, the operation proceeds to step 1
Proceed to 130. In step 1080, a variable THDW for determining downshift is calculated from the variable SPD indicating the vehicle speed and the variable SFT indicating the shift position from the characteristic diagram as shown in FIG.

At the following step 1090, the variable THC set at step 1050 or step 1060 is set.
Is greater than THDW, the process proceeds to step 1110 if an affirmative determination is made here, and the process proceeds to step 1130 if a negative determination is made. In step 1110, shift down is executed. The counter processing is omitted.

In the following step 1190, the state of the solenoid is set in order to drive the transmission 75 so that the changed gear position is reached, and this processing is once terminated. On the other hand, in step 130, the variable SFT is 1 or TH.
Since C ≦ THDW, it is determined whether the variable SFT is less than 4, and if an affirmative determination is made here, step 1140
If, on the other hand, a negative determination is made, the operation proceeds to step 1190.

In step 1140, the variable THUP for judging the upshift is calculated based on the variables SPD and SFT using the characteristic diagram as shown in FIG. In the following step 1150, it is determined whether THC is lower than THUP or not.
Proceed to. If there is a shift-up command, THC is set to a sufficiently small value in step 1060, so the routine always proceeds to step 1160.

In step 1160, shift up processing is performed, and then step 1190 is entered to end this processing. As described above, in this embodiment, the same effect as that of the first embodiment is obtained, and step 1060 is performed.
, TH / 4 = THC is set, so when there is a shift up command and there is a shift up command,
There is an advantage that it is possible to encourage shift up.

The present invention is not limited to the above-described embodiment, and it goes without saying that the present invention can be implemented in various forms without departing from the scope of the present embodiment. (1) For example, in the first embodiment, in order to prohibit upshifting when a predetermined condition such as water temperature is satisfied,
Although the shift hold command is output in step 740, it may be controlled together with it (or separately from its control) so as to make it difficult to shift up. Specifically, for example, the shift line used when shifting up may be changed so that it is difficult to shift up. This also tends to make it difficult for the engine speed to decrease, so that an effect similar to that of the first embodiment can be obtained.

(2) Further, in addition to the control by the shift hold command or the control for making it difficult to shift up (or separately from the control), the control for facilitating the shift down may be executed. Specifically, for example, the shift line used when shifting downshifts may be changed so as to facilitate downshifting. This also tends to make it difficult for the engine speed to decrease, so that a favorable effect can be obtained.

(3) Further, when a predetermined condition such as water temperature is satisfied, the shift down may be performed. This also lowers the engine speed, so that a more preferable effect can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram illustrating a basic configuration of claim 1.

FIG. 2 is a schematic configuration diagram showing an internal combustion engine and its peripheral devices to which the vehicle driving force control device of the first embodiment is applied.

FIG. 3 is a block diagram showing an electrical configuration of the first embodiment.

FIG. 4 is a flowchart showing a brake control process.

FIG. 5 is a flowchart showing engine torque reduction control.

FIG. 6 is an explanatory diagram used for calculation of output torque,
(A) shows the relationship between the engine speed and the throttle opening, and (b) shows the relationship between the throttle opening and the output torque.

FIG. 7 is a flowchart showing an injection control routine.

FIG. 8 is a map for performing correction by the injection cylinder.

FIG. 9 is a flowchart showing an outline of processing for controlling a shift position according to water temperature and the like.

FIG. 10 is a flowchart showing a shift control routine during traveling.

FIG. 11 is a characteristic diagram used to determine a shift.

FIG. 12 is an explanatory diagram used to calculate a water temperature correction coefficient, where (a) shows the relationship between FW and cooling water temperature, and (b) shows the relationship between FN and engine speed.

13A and 13B are graphs showing experimental results, where FIG. 13A shows an example and FIG. 13B shows a conventional example.

FIG. 14 is a flowchart showing a shift control routine during traveling of the second embodiment.

FIG. 15 is a graph used for explaining the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 40 ... Acceleration slip control circuit 49 ... Engine speed sensor 52 ... Throttle opening sensor 60 ... Engine control circuit 63 ... Catalyst temperature sensor 67 ... Water temperature sensor 77 ... Gear shift position detection switch 78 ... Gear shift control circuit

Claims (7)

[Claims] 1. A vehicle driving force control device for controlling a fuel injection amount and a shift position of a transmission according to an operating state of a multi-cylinder engine having an exhaust purification catalyst in an exhaust system, and detecting the engine speed. An engine speed detecting means, a fuel cut control means for cutting fuel supply for each cylinder in accordance with a state of acceleration slip of the vehicle, and an engine speed detected by the engine speed detecting means is a predetermined value or more. And a shift-up control unit that shifts up the shift stage of the transmission to a high-speed stage when fuel cut is being performed by the fuel cut control unit, and determines whether the engine is warmed up or at low temperature. A temperature state determining means, a low temperature fuel increase control means for increasing the amount of fuel when the temperature state determining means determines that the temperature is low, and the temperature state determining means. A vehicle driving force control device comprising: a shift-up suppressing unit that suppresses a shift-up by the shift-up controlling unit when the determining unit determines that the temperature is low. 2. The vehicle driving force control device according to claim 1, wherein the shift-up suppressing unit prohibits shift-up. 3. The vehicle driving force control device according to claim 1, wherein the shift-up suppressing means holds a shift position. 4. The vehicle driving force control device according to claim 1, wherein the upshift suppressing means performs downshifting. 5. The vehicle driving force control device according to claim 1, wherein the shift-up suppressing unit changes the shift timing so that it is difficult to shift up. 6. The vehicle driving force control device according to claim 1, wherein the shift-up suppressing unit changes a shift timing so that shift-down can be easily performed. 7. The vehicle driving force control device according to claim 1, wherein when the engine speed falls below a predetermined judgment value, the control by the upshift suppressing means is permitted. .