JP2952879B2 - Vehicle acceleration slip control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling an acceleration slip of a vehicle by reducing an output torque of an internal combustion engine to a target torque by a fuel supply stop control.

[Related Art] Conventionally, there has been known a device that detects an acceleration slip from a difference between a rotation speed of a driving wheel and a rotation speed of a driven wheel, and suppresses an output torque of an internal combustion engine by fuel cut control when the acceleration slip occurs. For example, in the device proposed in Japanese Patent Application Laid-Open No. 58-8436, a configuration is adopted in which fuel cut control is performed stepwise according to the magnitude of the acceleration slip, and the output torque of the internal combustion engine is reduced by the magnitude of the acceleration slip. It can be controlled according to

When performing fuel cut control in such a device, fresh air containing sufficient oxygen O ₂ is exhausted to the exhaust system, and this O ₂ reacts with unburned HC components in the exhaust gas, A phenomenon of burning in an exhaust system is known.

[Problems to be Solved by the Invention] For this reason, if a large amount of unburned HC components is discharged into the exhaust gas during the fuel cut control, a problem due to the above-described phenomenon becomes a problem. In other words, when the exhaust gas contains a large amount of unburned HC components, it is not desirable to execute the fuel cut control.

On the other hand, in the internal combustion engine, during a warm-up operation or a high-load operation such as an acceleration state, the fuel increase control is executed in order to maintain a required rotation speed. Further, even when the exhaust gas temperature rises, the fuel increase control is executed to suppress the exhaust gas temperature. Therefore, when the engine is in a low warm state, in a high load operation state, or when the exhaust gas temperature rises, a part of the fuel whose amount is controlled to increase in the exhaust gas is discharged as unburned HC.

Therefore, if the fuel cut control is executed in such a state, there is a problem that unburned HC components react with oxygen O ₂ in the exhaust system to degrade exhaust system components such as a catalyst.

In consideration of the durability of the exhaust system components, it is conceivable to provide a guard so as not to perform the fuel cut control when the fuel increase control as described above is performed. There is a problem that the acceleration slip control, which is the original purpose, cannot be sufficiently performed.

Further, as an acceleration slip control device capable of executing fine control over a wide range, a device that executes ignition retard control in addition to fuel cut control has been conventionally considered. In such a device, since the exhaust gas temperature rises with the execution of the ignition retard control, the fuel increase control may be executed on the engine control side to suppress this. However, as described above, during the low warming environment and during the high-load operation, the fuel increase is originally performed by the engine control.In addition to this, when the fuel increase control accompanying the ignition retard is performed, the exhaust gas is reduced. The frequency of discharging oxygen O ₂ and unburned HC components increases,
There is a problem that it becomes difficult to protect the exhaust system components. Therefore, in spite of the fact that the device can be controlled over a wide range, it has been necessary to perform control so as not to execute the acceleration slip control depending on conditions.

The acceleration slip control device of the present invention can execute the fuel cut control even when the fuel increase control is executed, and can protect the exhaust system components. An object is to execute good acceleration slip control.

[Means for Solving the Problems] A vehicle acceleration slip control device according to the present invention, as illustrated in FIG. 1, changes the amount of fuel supplied to each cylinder of an internal combustion engine from an operating state of the internal combustion engine having a plurality of cylinders. Fuel supply amount calculating means for calculating the fuel supply amount, fuel supply means for supplying fuel to each cylinder of the internal combustion engine with the fuel supply amount calculated by the fuel supply amount calculating means, and driving driven by the internal combustion engine Drive wheel rotational speed detecting means for detecting the rotational speed of the wheel; accelerating slip amount calculating means for calculating an accelerating slip amount of the driving wheel using the detected driving wheel rotational speed as one parameter; Acceleration slip detection means for detecting an acceleration slip of the drive wheel based on the amount, and detecting acceleration slip of the drive wheel by the acceleration slip detection means, based on the calculated acceleration slip amount. Come
Target torque calculation means for calculating a target torque of the internal combustion engine required to control the drive wheels to a predetermined target acceleration slip amount; and the fuel supply means calculates the fuel supply amount calculation means based on an operation state of the internal combustion engine. Output torque calculating means for calculating the output torque of the internal combustion engine when fuel is supplied to all cylinders of the internal combustion engine at the fuel supply amount calculated in; and the target torque calculated by the target torque calculating means. Based on the output torque calculated by the output torque calculation means, a fuel supply stop cylinder number calculation means for calculating the number of cylinders to stop supplying fuel to control the output torque of the internal combustion engine to the target torque; A torque reduction means for limiting the cylinders to which the fuel supply means supplies fuel in accordance with the calculation result of the fuel supply stop cylinder number calculation means and reducing the output torque of the internal combustion engine; In the acceleration slip control device for a vehicle, the fuel supply amount calculating means includes: A fuel supply amount correcting means for reducing the fuel supply amount calculated by the preset ratio at a predetermined ratio, and supplying fuel to all cylinders of the internal combustion engine with the fuel supply amount corrected by the fuel supply amount correcting means. Determining the output torque of the internal combustion engine, and determining whether or not the target torque calculated by the target torque calculating means is equal to or less than the calculated corrected output torque; and When it is determined that the target torque is equal to or less than the corrected output torque, the fuel supply amount correction unit is operated to supply fuel to each cylinder of the internal combustion engine with the corrected fuel supply amount to the fuel supply unit. Let At the same time, the corrected output torque is set as the output torque used by the fuel-stop cylinder number calculation means to calculate the number of cylinders. If not,
Stopping the operation of the fuel supply amount correction means, causing the fuel supply means to supply fuel to each cylinder of the internal combustion engine with the fuel supply amount calculated by the fuel supply amount calculation means, and the fuel stop cylinder number calculation means And torque control switching means for setting the output torque calculated by the output torque calculation means as the output torque used to calculate the number of cylinders.

[Operation and Effect of the Invention] In the acceleration slip control device according to the present invention configured as described above, the fuel supply amount calculation means operates normally when the acceleration slip of the drive wheels is not detected by the acceleration slip detection means. The amount of fuel supplied to each cylinder of the internal combustion engine is calculated from the operating state of the engine, and the fuel supply means supplies fuel to all cylinders of the internal combustion engine at the calculated fuel supply amount.

On the other hand, when the acceleration slip of the drive wheel is detected by the acceleration slip detection unit, the target torque calculation unit calculates a target torque of the internal combustion engine necessary to control the drive wheel to a predetermined target acceleration slip amount, The determining means determines whether the calculated target torque is equal to or less than the corrected output torque. Note that the corrected output torque is determined by the fuel supply amount corrected by the fuel supply amount correction means at a predetermined rate by the fuel supply amount calculated by the fuel supply amount calculation means in accordance with the operating state of the internal combustion engine. This is the output torque when fuel is supplied to all cylinders of the engine.

When the determining means determines whether the target torque is equal to or less than the corrected output torque, the torque control switching means operates as follows according to the result of the determination.

That is, when the determination unit determines that the target torque is equal to or less than the corrected output torque, the torque control switching unit operates the fuel supply amount correction unit to supply the corrected fuel supply amount to the fuel supply unit. The fuel is supplied to each cylinder of the internal combustion engine by the amount, and the corrected output torque is set as the output torque used by the fuel stop cylinder number calculation means to calculate the number of cylinders.

Conversely, when the determination means determines that the target torque is not less than the corrected output torque, the torque control switching means stops the operation of the fuel supply amount correction means and causes the fuel supply means to output the fuel supply amount. The fuel is supplied to each cylinder of the internal combustion engine at the fuel supply amount calculated by the calculating means, and the output torque calculating means determines the operation of the internal combustion engine as the output torque used by the fuel stopped cylinder number calculating means to calculate the number of cylinders. A normal output torque of the internal combustion engine calculated based on the state is set.

That is, in the acceleration slip control device of the present invention,
When an acceleration slip occurs in the drive wheels, if the output torque of the internal combustion engine can be brought close to the target torque by the fuel supply amount correction means by reducing the fuel supply amount,
The fuel supply amount correcting means is operated, and conversely, if the output torque of the internal combustion engine is excessively reduced below the target torque in the fuel supply amount reduction correction by the fuel supply amount correcting means, the operation of the fuel supply amount correcting means is stopped. The operation of the fuel supply amount correcting means for correcting the fuel supply amount to decrease by a predetermined ratio is switched in accordance with the magnitude of the generated slip. The output torque of the internal combustion engine used when the fuel-stop cylinder number calculating means calculates the number of cylinders is determined by the fuel supply amount corrected by the fuel supply amount correcting means in accordance with the operation state of the amount correcting means. Output torque (corrected output torque) generated in the internal combustion engine when fuel is supplied to the fuel supply amount, and the fuel supply amount that has not been reduced by the fuel supply amount correction means (that is, the fuel supply amount calculation means). An output torque generated in the internal combustion engine when fueled internal combustion engine all the cylinders at out fuel supply amount) is switched to either. Therefore, in the fuel supply stop cylinder number calculation means, the number of cylinders for which fuel supply should be stopped in order to control the output torque of the internal combustion engine to the target torque is accurately calculated according to the operation state of the fuel supply amount correction means, The operation of the torque reduction means limits the cylinders to which the fuel supply means supplies fuel according to the calculation result.

Thus, according to the present invention, when the output torque of the internal combustion engine can be made close to the target torque by the fuel supply amount correcting means, the fuel supply amount correcting means is operated, and the fuel supply amount correcting means Since the output torque of the internal combustion engine can be controlled to the target torque by the torque reduction means, the torque reduction means reduces the fuel supply when an acceleration slip occurs, as compared to the conventional device that performs the slip control only by the fuel supply stop control that restricts the fuel supply cylinder. The number of prohibited cylinders (the number of fuel cut cylinders) decreases.

Therefore, according to the present invention, it is possible to reduce the content of oxygen O _{2 in} the exhaust gas caused by the operation of the torque reducing means (that is, the fuel cut) as compared with the above-described conventional device.
Further, according to the present invention, when the fuel supply amount correcting means is operated, the air-fuel ratio of the fuel mixture supplied to the internal combustion engine is controlled to the lean air-fuel ratio, so that the unburned HC component in the exhaust gas also decreases. can do. Therefore, according to the present invention, it is possible to suppress the reaction between oxygen O ₂ and unburned HC in the exhaust system of the internal combustion engine as compared with the above-described conventional device, and to protect the components of the exhaust system from the combustion reaction. .

Further, in the present invention, the fuel supply amount correction means corrects the fuel supply amount calculated by the fuel supply amount calculation means at a predetermined ratio so as to reduce the amount of fuel mixture supplied to the internal combustion engine. The fuel ratio is controlled to the lean air-fuel ratio, and the correction amount for reducing the fuel supply amount is not corrected according to the degree of slip generated on the drive wheels. As a result, according to the present invention, the air-fuel ratio of the fuel mixture supplied to the internal combustion engine is controlled by the fuel supply amount correcting means to a lean air-fuel ratio that can sufficiently reduce nitrogen oxides (NOx) in the exhaust gas. The air-fuel ratio becomes an intermediate air-fuel ratio that is slightly leaner than the stoichiometric air-fuel ratio,
NOx can be prevented from increasing.

That is, as a technique for suppressing the output torque of the internal combustion engine to prevent the acceleration slip, there is also known a technique of controlling the fuel supply amount to the internal combustion engine according to the degree of slip generated on the drive wheels. and the fuel supply amount control such, when combined with the fuel supply stop control, similar to the present invention, although the oxygen O ₂ in the exhaust system and the non-variable HC can be prevented from reacting, internal combustion The air-fuel ratio of the fuel mixture supplied to the engine is controlled in the entire region on the lean air-fuel ratio side where the fuel component is smaller than the stoichiometric air-fuel ratio. The NOx component in it may increase. However, in the present invention, since the fuel supply amount is merely reduced at a predetermined ratio, the air-fuel ratio becomes an intermediate air-fuel ratio at which a large amount of NOx is generated by making the ratio of the reduction correction sufficiently large. Can be prevented. Therefore, according to the present invention, the acceleration slip can be suppressed without increasing the NOx component in the exhaust gas.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

First, FIG. 2 is a schematic configuration diagram showing the entire configuration of an acceleration slip control device according to an embodiment in which the present invention is applied to a front engine / rear drive (FR) type vehicle using a six-cylinder internal combustion engine 2 as a power source. .

The acceleration slip control device according to the present embodiment calculates an acceleration slip control circuit 4 that calculates control amount data for suppressing the output torque of the internal combustion engine 2 based on the acceleration slip amount of the vehicle.
And an internal combustion engine control circuit 6 for executing fuel injection amount control and ignition timing control for each cylinder of the internal combustion engine 2.

The internal combustion engine 2 is configured so that the target of the air-fuel ratio control can be switched between a stoichiometric air-fuel ratio and a predetermined lean air-fuel ratio as described later.

The internal combustion engine control circuit 6 includes a CPU 6a, a ROM 6b, a RAM 6
It is configured as a logical operation circuit centered on c etc.,
Detection signals from various sensors for detecting the operation state of the internal combustion engine 2 and control data for acceleration slip control output from the acceleration slip control circuit 4 are input to the input interface 6d.
The fuel injection amount and the ignition timing for each cylinder of the internal combustion engine 2 are calculated based on the data. The internal combustion engine control circuit 6 sends a control signal corresponding to the calculation result to the fuel injection valve 8 and the igniter 10 of each cylinder via the output interface 6e, and controls the driving of these to thereby control the fuel injection of the internal combustion engine 2. Control the quantity and ignition timing.

The internal combustion engine 2 has an intake air temperature sensor for detecting the temperature (intake air temperature) of intake air flowing into the intake passage 2a near the air cleaner 12 as a sensor for detecting the operating state of the internal combustion engine 2.
14. A throttle opening sensor 20 for detecting the opening (throttle opening) of a throttle valve 18 opened and closed by an accelerator pedal 16, and an intake pressure for detecting a pressure (intake pipe pressure) in a surge tank 22 for suppressing intake pulsation. Sensor 24, exhaust passage
An air-fuel ratio sensor 28 upstream of the three-way catalyst 26 for exhaust purification provided in 2b and detecting the oxygen concentration in the exhaust,
Water temperature sensor 30, which detects cooling water temperature, spark plug for each cylinder
A rotation angle sensor 36 that outputs a pulse signal every time the internal combustion engine 2 rotates at 30 ° C. in accordance with the rotation of the distributor 34 that distributes high voltage to the motor 32, and once per rotation of the distributor 34 (that is, the rotation of the internal combustion engine 2). A cylinder discriminating sensor 38 that outputs a pulse signal at a rate of once every two rotations) is provided. Detection signals from these sensors are taken into the internal combustion engine control circuit 6 via the input interface 6d as described above. In addition, by controlling the fuel injection amount based on the detection value of the air-fuel ratio sensor 28, combustion is performed at the stoichiometric air-fuel ratio during normal operation.

Next, the acceleration slip control circuit 4 includes an internal combustion engine control circuit 6
Similarly to the above, it is configured as a theoretical operation circuit centered on the CPU 4a, ROM4, RAM4c, etc.
0, left and right driven wheel speed sensors 42FL, 42FR for detecting the detection signals from the intake pressure sensor 24 and the rotation angle sensor 36, and the rotational speeds of the left and right front wheels (driven wheels) 40FL, 40FR of the vehicle, respectively.
Similarly, detection signals from left and right drive wheel speed sensors 42RL, 42RR as drive wheel rotation speed detection means for detecting the rotation speeds of the left and right rear wheels (drive wheels) 40RL, 40RR of the vehicle are input via an input interface 4d. The acceleration slip amount is calculated based on the acquired data, and the occurrence of the acceleration slip is detected based on the calculation result. When the occurrence of the acceleration slip is detected, the acceleration slip control circuit 4
Calculates control amount data for output torque control of the internal combustion engine 2 and sends control data corresponding to the calculation result to the internal combustion engine control circuit 6 via the output interface 4e.

The rotation of the crankshaft 2c of the internal combustion engine 2 is controlled by the drive wheel 40R.
The power transmission system transmitting to L and 40RR has a torque converter 44
An automatic transmission 44 provided with a is provided, and the output torque of the internal combustion engine 2 is transmitted to the drive wheels 40RL and 40RR via the automatic transmission 44 and a well-known differential gear 46.

Next, the acceleration slip control process executed by the acceleration slip control circuit 4 will be described with reference to the flowchart shown in FIG.

This acceleration slip control process is performed for a predetermined time (several msec.).
When the process is started, first, step 110 is executed, and the left and right driving wheel speed sensors 42RL,
Based on the detection signals from the 42RR and the left and right driven wheel speed sensors 42FL and 42FR, a drive wheel speed VR and a vehicle body speed VF are calculated, respectively. The drive wheel speed VR is determined by the left and right drive wheel speed sensors 42R.
L, the rotational speeds VRL and VRR of the left and right drive wheels 40RL and 40RR are determined based on the detection signals from the 42RR, respectively, and are set by selecting the larger one thereof.
The rotation speeds VFL and VFR of the left and right driven wheels 40FL and 40FR are determined based on the detection signals from the left and right driven wheel speed sensors 42FL and 42FR, and the larger one is selected.

Next, at step 120, the vehicle speed determined at step 110
By multiplying the preset target slip ratio Ks in VF (e.g. 0.1), the drive wheels 40RL, and calculates the target slip amount V ₀ which 40RR. In the following step 130, the actual slip amount Vj of the drive wheels 40RL, 40RR is calculated by taking the difference between the vehicle body speed VF and the drive wheel speed VR, and the routine proceeds to the subsequent step 140, where the actual slip amount Vj A deviation ΔV from the target slip amount V ₀ obtained at 120 is calculated.

Next, in step 150, it is determined whether or not the control execution flag F set during execution of the acceleration slip control is in a reset state. If the control execution flag F is in a reset state, that is, the acceleration slip control is currently being executed. if, then proceeds to the next step 160, whether on whether the deviation ΔV between the target slip amount V ₀ between the actual slip amount Vj is a positive value, the drive wheels 40RL, acceleration slip 40RR occurs whether Judge. If ΔV> 0, drive wheels 40RL, 40R
It is determined that an acceleration slip has occurred in R, and the flow proceeds to step 170 to set the control execution flag F, and then proceeds to step 180. Conversely, if ΔV ≦ 0, it is determined that no acceleration slip has occurred in the drive wheels 40RL and 40RR, and the routine proceeds to step 370 described later.

On the other hand, if it is determined in step 150 that the acceleration slip control is being executed, the process proceeds to step 180 without passing through steps 160 and 170.

In step 180, the average rotation speed (drive wheel average speed) VRO of the left and right drive wheels 40RL and 40RR is calculated based on the detection signals from the left and right drive wheel speed sensors 42RL and 42RR, and the rotation angle sensor 36 and the intake pressure sensor 24 , The rotational speed NE of the internal combustion engine 2 and the intake pipe pressure PM are calculated. Then, in step 190, based on the rotational speed NE of the internal combustion engine 2 and the average driving wheel speed VRO obtained in step 180, the reduction ratio γ (= NE / NE) in the power transmission system from the internal combustion engine 2 to the driving wheels 40RL and 40RR. VRO).

Next, at step 200, a preset integration constant GI
Then, the target drive wheel torque integral term TSl is updated using the following equation (1) from the deviation ΔV obtained in step 140 and the current target drive wheel torque integral term TSl.

TSI = TSI−GI · ΔV (1) Next, at step 210, a preset proportional constant G
From P and the deviation ΔV, a target drive wheel torque proportional term TSP is calculated using the following equation (2).

TSP = −GP · ΔV (2) Then, in step 220, the target drive wheel torque integral term TSI and the target drive wheel torque proportional term TSP are added to obtain a target drive wheel torque TS as a control target. The determination is made, and the process proceeds to subsequent step 230.

In step 230, the output torque (target engine torque) TE of the internal combustion engine 2 corresponding to the target drive wheel torque TS is calculated by dividing the target drive wheel torque TS obtained above by the reduction ratio γ obtained in step 190. In the following step 240, the maximum engine torque TMAX of the internal combustion engine 2 in this state is calculated from a preset map based on the rotational speed NE of the internal combustion engine 2 and the intake pipe pressure PM obtained in step 180.

Then, the process proceeds to step 250, where the target engine torque TE
And the maximum engine torque TMAX, that is, the target torque reduction rate (1-TE) corresponding to the deviation ΔV representing the amount of acceleration slip.
/ TMAX) is equal to or greater than the leaning torque reduction rate LVAF (5% reduction rate in this embodiment) when the air-fuel ratio leaning control is executed. Target torque reduction rate (1-TE
If (/ TMAX) is equal to or greater than the lean torque reduction rate LVAF, the process proceeds to step 260, where the lean coefficient KAF (coefficient corresponding to the lean torque reduction rate LVAF = 0.05) is set to a predetermined value (corresponding to the stoichiometric air-fuel ratio). Assuming that the coefficient is 1.0, for example, 0.85) is set.

In the following step 270, the maximum engine torque TMAX is multiplied by the leaning torque reduction rate LVAF to correct the maximum engine torque TMAX when the air-fuel ratio leaning is executed.

Subsequently, the routine proceeds to step 280, where the fuel for controlling the output torque of the internal combustion engine 2 to the target engine torque TE is calculated from the corrected maximum engine torque TMAX and the target engine torque TE using the following equation (3). The number of cylinders to be cut (cylinder cut number) NC is calculated.

NC = INT [KC ｛{1- (TE / TMAX)}] (3) In the above equation (3), KC represents the total number of cylinders of the internal combustion engine 2 (6 in this embodiment), and INT [ ] Represents an integer obtained by truncating the numerical value in [] below the decimal point.

On the other hand, when the target torque reduction rate (1-TE / TMAX) is smaller than the leaning torque reduction rate LVAF, that is, when the deviation (acceleration slip amount) ΔV is not so large and the output torque of the internal combustion engine 2 should be reduced. After the determination in step 250, the process proceeds to step 290, where the leaning coefficient KAF is set to 1.0.
, That is, not to execute the leaning of the air-fuel ratio. Therefore, in this case, in step 280, the maximum engine torque TMAX obtained in step 240 is used for calculating the cylinder cut number NC.

Subsequently, the routine proceeds to step 300, where the ignition timing of the internal combustion engine 2 is set to 1 ° C. using a preset map based on the rotational speed NE and the intake pipe pressure PM of the internal combustion engine 2 obtained in step 180.
An output torque reduction rate (retardation torque reduction rate) TCA of the internal combustion engine 2 that can be suppressed by retarding A is calculated.

Then, in step 310, when only the fuel cut control is executed based on the cylinder cut number NC calculated by the equation (3), the ignition timing corresponding to the output torque of the internal combustion engine 2 exceeding the target torque TE Is calculated from the following equation (4).

If the retardation control amount Δθ calculated here exceeds the controllable maximum retardation control amount ΔθMAX, regardless of the calculation result based on the equation (4), the maximum retardation control amount Δθ is set as the maximum retardation control amount Δθ. Set the amount ΔθMAX.

When the cylinder cut control number NC and the ignition retard control amount Δθ for the acceleration slip control are calculated as described above, the process proceeds to step 320, and the calculated control data is output to the internal combustion engine control circuit 6. Then, the internal combustion engine control circuit 6 performs the fuel cut control and the ignition timing retard control, and in some cases, the air-fuel ratio lean control according to the control data, and suppresses the output torque of the internal combustion engine 2.

In step 320, when control data (NC, Δθ, KAF) for acceleration slip control is output to the internal combustion engine control circuit 6,
The process proceeds to step 330 to determine whether the deviation ΔV obtained in step 140 is equal to or less than 0, that is, whether the acceleration slip is suppressed. And if ΔV> 0,
Since the acceleration slip is continuing, the process is temporarily ended as it is. If ΔV ≦ 0, the process proceeds to the subsequent step 340,
The counter C for counting the state of ΔV ≦ 0 is incremented, and the process proceeds to the subsequent step 350.

In step 350, the value of the counter C whether exceeds a predetermined value C _0, that is, a state of the [Delta] V ≦ 0, it is determined whether the elapsed predetermined time or more. If a negative determination is made in step 350, the process is terminated once, otherwise, it is determined that there is no longer any acceleration slip on the drive wheels 40RL, 40RR, and the routine proceeds to step 360, where control of the internal combustion engine is performed. The output of the control data to the circuit 6 is stopped. Then, in the subsequent steps 370 to 390, for the next acceleration slip control, an initialization process for initializing the counter C, the control execution flag F, and the target driving wheel torque integral term TSI is executed, and the process is once executed. finish.

In this initialization process, the value of the counter C is set to 0 in step 370, the control execution flag F is reset in step 380, and the initial value TSI ₀ is set in the target torque integration term TSI in step 390. Performed in steps. In addition, in the initialization process, in step 160, the deviation ΔV
Is smaller than or equal to 0, and it is determined that no acceleration slip has occurred in the drive wheels 40RL and 40RR.

Next, based on the flowcharts of FIGS. 4 and 5,
The engine control process based on the control amount data NC, Δθ and KAF sent out at step 320 for acceleration control will be described.

First, FIG. 4 shows an actual control amount (actual control amount) of the internal combustion engine 2 for performing the fuel injection control and the ignition timing control of the internal combustion engine 2 in the internal combustion engine control circuit 6, that is, the fuel injection amount and the ignition timing. 5 is a flowchart illustrating an actual control amount calculation process executed to calculate the control amount.

This actual control amount calculation process is a process that is repeatedly executed after the start of the internal combustion engine 2 by the internal combustion engine control circuit 6. When the process is started, first, step 710 is executed to determine the rotation speed NE of the internal combustion engine 2. Based on the intake pipe pressure PM, the basic fuel injection amount τo is calculated using a preset map. In the subsequent step 720, the intake air temperature sensor 14, the air-fuel ratio sensor 28,
Based on detection signals from the water temperature sensor 30 and the like, various known fuel correction coefficients Kτ for performing warm-up correction of the fuel injection amount, air-fuel ratio correction, and the like are calculated.

In the subsequent step 725, the leaning coefficient KAF sent from the acceleration slip control circuit 4 in step 320 is read.

Next, the process proceeds to step 730, where the various fuel correction coefficients Kτ calculated in step 710, the basic fuel injection amount τo obtained in step 710, and the leaning coefficient KAF read in step 725 are multiplied by each other, and Fuel injection valve 8
From the fuel injection amount τ is calculated. Therefore, in the acceleration slip control, when the air-fuel ratio leaning control is executed, the leaning coefficient KAF = 0.85 is set in step 260 as described above, so that the leaning coefficient is set to be smaller than the control corresponding to the stoichiometric air-fuel ratio. The fuel injection charge τ decreases.

When the fuel injection amount τ is set in this manner, the process proceeds to step 740, in which the number of fuel cut cylinders NC output from the acceleration slip control circuit 4 is read in step 320, and the read value is read in step 750. A cylinder to be subjected to fuel cut control is set based on the fuel cut cylinder number NC.

In the following step 760, the rotational speed NE of the internal combustion engine 2 is set.
The basic ignition timing θo is calculated by using a preset map based on the intake air pressure PM and the intake pipe pressure PM, and the routine proceeds to step 770, where ignition is performed based on detection signals from the intake air temperature sensor 14, the water temperature sensor 30, and the like. Various known ignition correction amounts θx for performing timing warm-up correction and the like are calculated. Next step 78
In step 0, the ignition retard control amount Δθ output from the acceleration slip control circuit 4 is read in step 320, and the next step 79
The basic ignition timing θo is retarded or advanced based on the read ignition retard control amount Δθ and the calculated various ignition correction amounts θx, and the ignition of the internal combustion engine 2 as a control target is shifted to 0. The timing θ is determined, and the process returns to step 710.

Next, FIG. 5 shows the internal combustion engine control circuit 6, which includes a rotation angle sensor 36.
Represents a crank angle interruption process executed at every predetermined rotation angle of the internal combustion engine 2 based on the detection signal from the internal combustion engine 2. This process is performed by a timer circuit (not shown) provided in the output interface 6e based on the actual control amount of the internal combustion engine 2 calculated in the actual control amount calculation process, that is, the fuel injection amount τ and the ignition timing θ. , The opening and closing times of the fuel injection valves 8 of the respective cylinders are set, and the output timing of the ignition signal to the igniter 10 (that is, the ignition timing) is set. Igniter 10
Is a process for actually driving.

As shown in the figure, when this crank angle interrupt processing is started, first, step 810 is executed to determine whether or not it is the current fuel injection amount setting timing, and if it is the current fuel injection amount setting timing, The process proceeds to step 820 to determine whether or not the cylinder at which the fuel injection amount is currently set is the fuel cut cylinder set in step 750. If it is determined in step 820 that the cylinder at which the fuel injection amount is currently set is not the fuel cut cylinder, the process proceeds to step 830.
Based on the fuel injection amount τ calculated in the actual control amount calculation processing, the opening and closing times of the fuel injection valve 8 of the specific cylinder are set, and the routine proceeds to step 840.

Step 840 is performed when it is determined in step 810 that it is not the current fuel injection amount setting timing, or when step 820
The processing is also executed when it is determined that the cylinder at which the fuel injection amount is set is a fuel cut cylinder, and it is determined whether or not it is the current ignition timing setting timing. If it is the current ignition timing setting timing, the process proceeds to the subsequent step 850, where the output timing of the ignition signal to the igniter 10 is set based on the ignition timing θ calculated in the actual control amount calculation process, and the process is performed. Stop once.

As described above, the internal combustion engine control circuit 6 calculates the fuel injection amount τ and the ignition timing θ according to the operation state of the internal combustion engine 2,
The fuel injection valve 8 and the igniter 10 are drive-controlled according to the calculation result, and when the control amount data for the acceleration slip control is output from the acceleration slip control circuit 4, the fuel cut-off is performed according to the control amount data. Control and ignition timing retard control, and in some cases, air-fuel ratio lean control are executed.

The cylinder cut number NC, the ignition retard control amount Δθ, and the leaning coefficient K obtained by the acceleration slip control circuit 4 as described above.
Based on the AF, the internal combustion engine control circuit 6 controls the fuel cut,
The ignition timing retard control and, in some cases, the air-fuel ratio lean control are executed.

In the present embodiment, the processing of steps 110 to 140 executed in the acceleration slip control circuit 4 is performed by the acceleration slip amount calculation means, the processing of steps 150 to 170 is performed by the acceleration slip detection means, and the processing of steps 180 to 230 is performed. To the target torque calculation means, the processing of step 240 to the output torque calculation means, the processing of step 250 to the determination means, step 260, 270
And 290 correspond to the torque control switching means, and the processing of step 280 corresponds to the fuel stopped cylinder number calculating means. Step 71 executed in the internal combustion engine control circuit 6
Steps 0 to 730 are executed by the fuel supply amount calculating means, in which the leaning coefficient KAF is read to correct the fuel injection amount.
The processing of 25,730 reads the number of fuel cut cylinders NC to the fuel supply amount correction means and sets the fuel cut cylinder at step 74.
The processing of 0,750 corresponds to the torque reducing means, and the processing of steps 810 to 830 executed for driving the fuel injection valve corresponds to the fuel supply means, respectively.

As described above, in the acceleration slip control device of the present invention, the basic fuel injection amount is suppressed by executing the lean air-fuel ratio, and the fuel increase amount executed at the time of low temperature, high load, or retard control is performed. The increase by the control can be apparently executed. As a result, when the need for acceleration slip control arises during low warm-up conditions or high-load operation,
Since the amount by which the engine torque is to be reduced by the fuel cut control is reduced by making the air-fuel ratio lean, the number of cylinder cuts NC may be small, and the content of oxygen O _{2 in} the exhaust gas is small. Further, since the fuel injection amount itself decreases due to the lean air-fuel ratio, the unburned HC component in the exhaust gas also decreases. Therefore, the factors that cause the combustion reaction in the exhaust system can be suppressed, and the overheating of the catalyst 26 and the like can be prevented from deteriorating. In other words, in such a case, it is possible to execute the fuel cut control having a high engine torque reduction effect, and it is possible to obtain good acceleration slip control performance over a wide range in all driving states.

When the required torque reduction rate (1-TE / TMAX) in the acceleration slip control is smaller than the lean torque reduction rate LVAF, the fuel cut control and the ignition retard control are performed as they are, and the required torque reduction rate is obtained. When (1-TE / TMAX) is equal to or greater than the leaning torque reduction rate LVAF, the air-fuel ratio leaning control is executed, and then the engine torque that exceeds it is supplemented by the fuel cut control and the ignition retard control. However, when only the air-fuel ratio lean operation is performed, a torque step is generated. On the other hand, in this embodiment, the linearity is increased from TE / TMAX ≒ 1 with a small required amount of acceleration slip control to TE / TMAX ≒ 0 with a large required amount. Can be controlled. As a result, it is possible to appropriately respond to the demand for the acceleration slip control.

Also, the basic fuel injection amount τ obtained based on the stoichiometric air-fuel ratio
Since o is multiplied by various fuel correction coefficients Kτ and further multiplied by a leaning coefficient KAF, the fuel injection control is performed in the same procedure regardless of whether the air-fuel ratio leaning control is executed or not. Can be performed.

In calculating the target torque TE or the like, the target torque TE or the like may be directly obtained from the deviation between the actual slip amount of the drive wheels and the target slip amount using a map or the like.

Also, in calculating the acceleration slip amount, a road surface state detecting means for emitting ultrasonic waves or the like to the road surface to detect the unevenness of the road surface to detect a friction coefficient of the road surface, or snow and rain depending on the road surface condition during traveling. -Provide a switch for selecting the condition of the road surface such as ice and gravel roads and provide road surface condition setting means for setting the friction coefficient of the road surface, and obtain the rotation speed of the drive wheels and the friction coefficient of the road surface using a map or the like. It may be configured.

Further, the present invention can be applied to a device that does not perform the ignition retard control.

In addition, without departing from the gist of the present invention,
For example, various modes can be adopted, such as application to a device that only performs fuel cut control or a device that can also execute subthrottle control.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, FIG. 2 is a schematic configuration diagram showing the overall configuration of an acceleration slip control device of an embodiment, and FIG. 3 shows an acceleration slip control process executed by an acceleration slip control circuit. FIG. 4 is a flowchart illustrating an actual control amount calculation process executed by the internal combustion engine control circuit, and FIG. 5 is a flowchart illustrating a crank angle interruption process executed by the internal combustion engine control circuit. 2 Internal combustion engine, 40RL, 40RR Drive wheel 4 Acceleration slip control circuit 6 Internal combustion engine control circuit 42RL, 42RR Drive wheel speed sensor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F02D 29/02 B60K 28/16 F02D 41/14 F02D 41/36

Claims (1)

(57) [Claims] 1. A fuel supply amount calculating means for calculating a fuel supply amount to each cylinder of an internal combustion engine from an operating state of an internal combustion engine having a plurality of cylinders, and a fuel supply amount calculated by the fuel supply amount calculating means. Fuel supply means for supplying fuel to each cylinder of the internal combustion engine in an amount; drive wheel rotational speed detecting means for detecting a rotational speed of a drive wheel driven by the internal combustion engine; and the detected drive wheel rotational speed. Acceleration slip amount calculation means for calculating the acceleration slip amount of the drive wheel using the following as one parameter: acceleration slip detection means for detecting the acceleration slip of the drive wheel based on the calculated acceleration slip amount; When the acceleration slip of the drive wheel is detected, the target torque of the internal combustion engine required to control the drive wheel to a predetermined target acceleration slip amount based on the calculated acceleration slip amount. A case where the fuel supply unit supplies fuel to all cylinders of the internal combustion engine at a fuel supply amount calculated by the fuel supply amount calculation unit based on a target torque calculation unit to be calculated and an operation state of the internal combustion engine. Output torque calculating means for calculating the output torque of the internal combustion engine, and the output torque of the internal combustion engine based on the target torque calculated by the target torque calculating means and the output torque calculated by the output torque calculating means. Fuel supply stop cylinder number calculation means for calculating the number of cylinders for which fuel supply should be stopped for controlling to the target torque; and the fuel supply means supplies fuel in accordance with the calculation result of the fuel supply stop cylinder number calculation means. And a torque reduction means for reducing the output torque of the internal combustion engine by limiting the cylinders that perform Fuel supply for reducing the fuel supply amount calculated by the fuel supply amount calculation means by a preset ratio so that the air-fuel ratio of the aiki becomes a predetermined lean air-fuel ratio smaller than the stoichiometric air-fuel ratio. An output torque of the internal combustion engine when fuel is supplied to all cylinders of the internal combustion engine with the fuel supply amount corrected by the fuel supply amount correction unit, and calculated by the target torque calculation unit. Determining means for determining whether or not the target torque is equal to or less than the calculated corrected output torque; and when the determining means determines that the target torque is equal to or less than the corrected output torque, Operating the fuel supply amount correction means to supply fuel to each cylinder of the internal combustion engine with the corrected fuel supply amount to the fuel supply means,
The corrected output torque is set as the output torque used by the fuel stop cylinder number calculation means to calculate the number of cylinders, and conversely, if the target torque is not less than or equal to the corrected output torque by the determination means. When it is determined, the operation of the fuel supply amount correction unit is stopped, and the fuel supply unit supplies fuel to each cylinder of the internal combustion engine at the fuel supply amount calculated by the fuel supply amount calculation unit, A torque control switching unit that sets the output torque calculated by the output torque calculating unit as an output torque used by the fuel stop cylinder number calculating unit to calculate the number of cylinders. Acceleration slip control device.