JPH06159109A - Driving force control device for vehicle - Google Patents

Abstract

PURPOSE:To improve engine durability, by continuously changing an cylinder to be stopped for uniforming the temperature in the inside of an internal combustion engine in cylinder cut-off operation. CONSTITUTION:In a cut-off cylinder calculating means the number of cylinders, for which fuel supply is to be stopped, is calculated based on the slip ratio of a driving wheel, calculated by a slip ratio calculating means, and the operation condition of an internal combustion engine, calculated by an operation condition detecting means. By an output torque control means, fuel supply stop control is performed according to the calculated result of a calculating means for the number of cylinders to be stopped and by changing in order a cylinder for stopping fuel supply. In a fuel quantity increase control means, fuel supply quantity to an internal combustion engine is controlled so as to supply fuel, to which a given increased quantity value is added, to only a cylinder returned to an operating condition from a fuel supply stop condition. At that time by an increased-quantity change control means, an increased-quantity value to be added, according to the number of cylinders to be stopped calculated by the calculating means for the number of cylinders to be stopped, is changed. Consequently, temperature distribution for all cylinders can be nearly made uniform to improve the durability of an internal combustion engine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular driving force control device, and more specifically, it controls a driving force from a torque generated by an engine by reducing a cylinder by stopping fuel supply to a specific cylinder to reduce the cylinder. The present invention relates to a vehicle driving force control device.

[0002]

2. Description of the Related Art As a driving force control device for a vehicle based on fuel supply control, for example, Japanese Patent Laid-Open No. 233855/1990 is known. This prior art is to dilute the air-fuel ratio of the supplied fuel to reduce the required number of stopped cylinders and unburned HC components to prevent the temperature rise of the exhaust system. In addition, a method is generally used in which the air-fuel ratio is made rich at the time of high load and the combustion chamber of the engine and the exhaust system are cooled by the excess fuel.

However, according to the above-mentioned conventional technique, while the air-fuel ratio of the fuel is diluted, the temperature of the combustion chamber of the cylinder during combustion rises, while the cylinder at rest is cooled by air. Therefore, the temperature inside the engine becomes non-uniform, and there is a problem that the durability of the engine deteriorates due to thermal strain.

Further, since the temperature of the exhaust system lowers, there is also a problem that the catalyst temperature lowers for a long period of the cylinder cut-off operation, resulting in a lower exhaust gas purification rate. Therefore, the present invention constantly replaces the cylinders to be stopped to equalize the temperature inside the internal combustion engine during reduced cylinder operation, and increases the amount in accordance with the number of stopped cylinders to prevent the temperature of the exhaust system from decreasing. It is an object of the present invention to provide a driving force control device for a vehicle.

[0005]

A vehicle driving force control system according to claim 1, which is made in order to achieve the above object, has a plurality of cylinders and has an exhaust system as illustrated by a solid line in FIG. An operating state detecting means for detecting an operating state of an internal combustion engine provided with an exhaust catalyst, and a drive wheel rotational speed detecting means for detecting a rotational speed of drive wheels driven by the internal combustion engine,
Slip ratio calculating means for calculating the slip ratio of the drive wheel using the detected drive wheel rotation speed as one parameter,
Based on the calculated slip ratio of the drive wheels and the detected operating state of the internal combustion engine, the number of stopped cylinders calculating means for calculating the number of cylinders for which fuel supply should be stopped, and the calculation result of the number of stopped cylinders calculating means are calculated. Accordingly, a vehicle driving force control device for controlling the driving force of the vehicle, comprising: a fuel supply stop control for stopping the fuel supply to a predetermined cylinder; and an output torque control means for controlling the output torque of the internal combustion engine. In the above, the output torque control means is configured such that the fuel supply stop control is executed by sequentially replacing the cylinders that stop the fuel supply, and the fuel supply stop state is returned to the operating state by the fuel supply stop control. Fuel increase control means for controlling the fuel supply amount to the internal combustion engine so that the fuel is supplied by adding a predetermined increase value only to the selected cylinders, and the number of stopped cylinders is calculated. Characterized in that and a boost value change control means for changing the increment value in response to the reduced-cylinder number of cylinders calculated by stages.

In addition to the structure according to claim 1, the vehicle driving force control device according to claim 2 detects a catalyst temperature for detecting the temperature of the exhaust catalyst as illustrated by a broken line in FIG. Means, and second increase value change control means for changing the increase value according to the catalyst temperature detected by the catalyst temperature detecting means.

[0007]

According to the vehicle driving force control device of the present invention having the above-mentioned structure, the stopped cylinder number calculating means is detected by the slip ratio of the driving wheels calculated by the slip ratio calculating means and the operating state detecting means. The number of cylinders for which fuel supply should be stopped is calculated based on the operating state of the internal combustion engine. Then, the output torque control means executes the fuel supply stop control in accordance with the calculation result of the stopped cylinder number calculation means and sequentially replaces the cylinders for which the fuel supply is stopped.

Further, the fuel increase control means controls the fuel supply amount to the internal combustion engine so that the fuel is supplied by adding the predetermined increase value only to the cylinders that have returned from the fuel supply stopped state to the operating state. At that time, the increase value change control means changes the increase value to be added according to the number of stopped cylinders calculated by the stopped cylinder number calculation means.

As described above, the cylinders to be stopped are not fixed but sequentially replaced and stopped, so that the temperature distributions of all the cylinders become closer to uniform and the durability of the internal combustion engine is improved. FIG. 11 shows an example of sequentially replacing the stopped cylinders (when stopping two cylinders out of six cylinders). In the figure, the symbol "○" indicates normal injection, that is, fuel injection in which the supplied cylinders are almost at the theoretical air-fuel ratio, the symbol "x" indicates injection stop, and the symbol "◎" adds a predetermined amount of fuel to normal injection. Each of the increased injections is shown. It should be noted that the engine rotation in the figure means the cumulative engine rotation after the start of the reduced cylinder operation in which the cylinder is stopped.

For example, when a cut-off cylinder operation is requested immediately before the injection of the first cylinder, the injection of the first cylinder and the fourth cylinder is stopped, and after two revolutions, the injection of the second cylinder and the fifth cylinder is stopped. Then
Increased injection is performed on the first cylinder and the fourth cylinder that resumed injection. After that, the stopped cylinders are sequentially replaced to equalize the temperature inside the engine.

In general, unless the increased fuel injection is performed, the temperature of the exhaust system, especially the temperature of the exhaust catalyst tends to decrease as the number of stopped cylinders increases. Furthermore, when the stopped cylinders are sequentially replaced as in the present invention. Since the fuel supply is frequently stopped / restarted, the combustion air-fuel ratio becomes lean when the fuel supply is restarted due to the generation of fuel adhered to the wall surface when the fuel supply is stopped, etc. On the contrary, when the number is small, the catalyst temperature itself may rise (see FIG. 12 (a)).

On the other hand, in the present invention, the fuel is supplied only to the cylinders that have returned from the fuel supply stopped state to the operating state, by adding the increase value according to the number of stopped cylinders. For example, when the number of stopped cylinders is small, the catalyst temperature is prevented from rising due to a misfire, and when the number of stopped cylinders is large, the amount of increase is increased and the combustion temperature in the catalyst is used to prevent the catalyst temperature from lowering (see FIG. 1).
2 (b)).

If the increase value is changed according to the detected catalyst temperature as in the vehicle driving force control device according to the second aspect, it becomes easier to maintain the temperature of the catalyst.

[0014]

EXAMPLES Examples of the present invention will be described below. First, the configuration will be described. In FIG. 2, reference numeral 1 denotes an engine for driving a vehicle, intake air is supplied from an air cleaner 2, an intake pipe 3, a throttle chamber 4 and each branch of an intake manifold 5 to each cylinder, and fuel is supplied to an injector (fuel supply). And is mixed with the intake air. A spark plug 7 is attached to each cylinder, and a high voltage pulse from an ignition coil 10 is supplied to the spark plug 7 via a distributor 8 at a timing at which a power transistor 9 is energized.

The air-fuel mixture in the cylinder is ignited and explodes by the discharge of the spark plug 7, becomes exhaust gas and is sent to the exhaust pipe 11.
In the catalytic converter 12, harmful components in the exhaust gas are cleaned by a three-way catalyst and discharged to the outside. The power of the engine 1 is transmitted to the drive shaft of the vehicle via the transmission 13 to drive the drive shaft.

The flow rate of the intake air is detected by the air flow meter 15 and controlled by the throttle valve 16 in the throttle chamber 4. The fully closed position of the throttle valve 16 is detected by a throttle valve switch 17, and the crank angle of the engine 1 is detected by a crank angle sensor 18 built in the distributor 8. Knocking generated in the engine 1 is detected by a knock sensor 19, and the temperature of cooling water is detected by a water temperature sensor 20.

The oxygen concentration in the exhaust gas is measured by the oxygen sensor 21.
The vehicle speed is detected by the vehicle speed sensor 22. The shift position of the transmission 13 is detected by the reverse switch 23, and the neutral position of the transmission 13 is detected by the neutral switch 24. The rotation speed of the drive wheels of the vehicle is measured by a drive wheel speed sensor (drive shaft rotation speed detecting means) 25.
The rotational speed of the driven wheel (non-driving wheel) is detected by a driven wheel speed sensor (non-driving wheel rotational speed detecting means) 26. The inlet exhaust gas temperature of the catalytic converter 12 is detected by the catalyst inlet temperature sensor 27, and the catalyst bed temperature of the catalytic converter 12 is detected by the catalyst bed temperature sensor 28.

Reference numeral 31 is an auxiliary air control valve, 32 is an air regulator, 33 is an air conditioning and heating solenoid valve, 34 is a negative pressure control valve, and 35 is a fuel pump. The signals from the respective sensors 15, 17 to 28 are inputted to the control unit 40, and the control unit 40 has functions as a slip ratio means, a supply amount calculation means and a supply amount control means,
It is mainly composed of a microcomputer. The control unit 49 performs ignition timing control of the engine, fuel supply control, and traction control of the vehicle based on the input signals.

FIG. 3 is a block diagram of a part of the control performed by the control unit 40, which implements the function of ignition timing control. In the figure, the multiplexer 41 switches each signal from the air flow meter 15, the water temperature sensor 20, the oxygen sensor 21, and the knock sensor 19 by the operation of the timer 42 to pass the analog signal.
CP after being converted into a digital signal by the D converter 43
Input to U44.

On the other hand, the signal from the crank angle sensor 18 is counted by the counter 46 by the operation of the timer 45, and a signal corresponding to the number of inputs per unit time is input to the CPU 44 as an engine speed signal. CPU
44 transmits / receives a signal to / from a memory, calculates an ignition timing suitable for an operating state based on the various signals, and outputs the calculation result to an output circuit 48. The reference angle signal from the crank angle sensor 18 is also input to the output circuit 48, and when the calculated ignition timing matches the power transistor 9
An ignition signal is output to the ignition coil 10 via the ignition coil 10, whereby the ignition plug 7 of a predetermined cylinder is discharged via the distributor 8 to ignite the air-fuel mixture.

The air flow meter 15, the throttle valve switch 17, the crank angle sensor 18, the water temperature sensor 20, and the oxygen sensor 21 constitute an operating state detecting means 51, and the ignition plug 7, the distributor 8, the power transistor 9 and the ignition coil 10 are provided. Ignition means 52 is configured.

Next, the operation will be described. First, the fuel injection control will be described. Based on the detected intake air amount Qa and the engine speed N, the basic injection amount Tp is calculated by the equation Tp = K · Qa / N. The fuel injection amount Ti is calculated by correcting the basic injection amount Tp based on the detected cooling water temperature, the oxygen temperature in the exhaust gas, and the like according to the following equation.

Ti = Tp × (1 + KTW + KAS + KAI + KACC + KDEC) × KFC + TB, 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: For battery voltage correction Then, a pulse signal corresponding to the calculated fuel injection amount Ti is output to the injector 6 to perform fuel injection control. During the fuel injection control, the driving force control routine shown in the flowchart of FIG. 4 is executed.

First, step 110 (hereinafter simply referred to as S110
Say The same applies below. ), Various signals such as the actual engine speed N and the vehicle speed VSP detected in step S120) are read, and it is determined whether or not the shift stage detected in S120 is a reverse stage. If YES, the process proceeds to S130, and if NO, that is, if the shift stage is the forward stage, the process proceeds to S180. In S130, the second fuel cut rotation speed NMA at the time of retreat as the second set rotation speed
In addition to setting XR, the second fuel cut vehicle speed VSPMAXR at the time of reverse as the second set vehicle speed is set in S140.

On the other hand, in S180, the first fuel cut vehicle speed NMAX during forward movement as the first set rotational speed is set, and in S190, the first fuel cut vehicle speed VSPMAX during forward movement as the first set vehicle speed is set. To do. Here, the second fuel cut rotation speed NMAXR is set to be lower than the first fuel cut rotation speed NMAX,
The fuel cut vehicle speed VSPMAXR is set to be smaller than the first fuel cut vehicle speed VSPMAX.

At S150, it is determined whether the engine speed N exceeds the second fuel cut speed NMAXR, and Y
If ES, the process proceeds to S170 without passing through S160, and if NO, the process proceeds to S160. Vehicle speed V in S160
It is determined whether or not SP exceeds the second fuel cut vehicle speed VSPMAXR. If YES, the process proceeds to S170, and if NO, the process proceeds to S220. In S170, the injection operation of the injector 6 is stopped to cut the fuel. Therefore, when the engine speed N exceeds the second fuel cut rotational speed NMAXR when the shift speed is in the reverse speed, or when the vehicle speed V
The fuel cut is performed when the vehicle speed exceeds the second fuel cut vehicle speed VSPMAXR.

On the other hand, when the shift stage is in the forward stage,
In S200, it is determined whether or not the engine speed N exceeds the first fuel cut rotational speed NMAX, and if YES, S
If not, the process proceeds to S210. S210
Then, it is determined whether or not the vehicle speed VSP exceeds the first fuel cut vehicle speed VSPMAX. If YES, then the process proceeds to S170, and if NO, then the process proceeds to S220. In S220, fuel injection control by the injector 6 is continued without performing fuel cut.

Therefore, when the shift stage is in the forward stage, the engine speed N is equal to the second fuel cut rotational speed NMA.
1st fuel cut rotation speed NMAX set larger than XR
When the vehicle speed VSP exceeds the first fuel cut vehicle speed VSPMAX which is set higher than the second fuel cut vehicle speed VSPMAXR, the fuel cut is performed.

From the above, the safety of the vehicle traveling can be achieved in the forward gear as in the conventional case, and also in the reverse gear in which the vehicle speed or the rotation speed during normal operation is set lower than that in the forward gear. Further, there is an effect peculiar to the present embodiment that the excessive increase of the vehicle speed or the rotation speed is effectively suppressed, and the safety of the vehicle traveling at the time of backward movement can be secured.

Next, the traction control routine, which is a feature of the present invention, is executed according to the flow chart of FIG. First, in S310 to S390, the intake air amount Qa, engine speed N cooling water temperature TW, catalyst bed temperature Tcc, catalyst inlet temperature Tci, vehicle speed VSP, knock signal Vk, drive shaft speed VDW, and driven wheel speed VPW are read. Next, in S400, the basic injection amount Tp (equal to the engine load) is calculated according to the above formula, and in S410, the slip ratio Sp is calculated.
Calculate L according to the following formula.

SL = (VDW-VPW) / VPW ... Then, in S420, a change dTcc (time differential value of Tcc) of the catalyst bed temperature Tcc per unit time is calculated, and in S430, per unit time of the catalyst inlet temperature Tci. Change of dTci (Tci
Time differential value of) is calculated. Next, at S440, the basic ignition timing ADV0 is set to the map MAP shown in FIG. 6 (a) using the basic injection amount TP and the engine speed N as parameters.
Look up from 1.

Similarly, in S450, the basic injection amount TP and the engine speed N are used as parameters in FIG. 6 (b).
The ignition timing ADV-5 at which the torque decreases by -5% (-5% torque ignition timing) is looked up from the map MAP2 shown in FIG. 6 and the basic injection amount Tp and the engine speed N are used as parameters in S460 in FIG. ) Map MA
Ignition timing (-1 when torque decreases from P3 by -10%
0% torque ignition timing) Look up ADV-10.

Next, in S470, it is judged from the knock signal Vk that knocking has occurred, in S480, SL0 to SL13 are ranked in 14 levels corresponding to the slip ratio SL, and in S490, the slip ratio SL is compared with the rank SLn. . As a result of ranking, if the slip ratio SL is large, S
If the slip ratio SL is small, it is judged that traction control is not necessary and the routine proceeds to S500.

In S500, the engine speed N is compared with the high speed fuel cut speed NMAX. If YES in S500, to perform fuel cut, S
If it is NO, the process proceeds to S510. S510
Then, it is determined whether the vehicle speed VSP is higher than 180 km,
When YES is selected, the fuel cut is similarly performed. Therefore, the process proceeds to S530, and when NO, the process proceeds to S520. S
At 520, KFC = 1.0 is set, and the fuel cut is not performed for all cylinders, and the process proceeds to S540. At S530, KFC = 0 is performed, the fuel cut is performed for all cylinders, and the process proceeds to S540 (see FIG. 7 for the fuel cut).

In S540, the knock signal Vk is the judgment value SL.
Whether or not it is greater than EL is determined, and the basic ignition timing ADV is retarded by β in S550 to determine the final ignition timing ADV. If NO, the basic ignition timing ADV0 is directly determined as the final ignition timing ADV in S560. Then
In S570, the fuel injection amount Ti is calculated from the above equation, and S5
At 80, this value Ti is set in the register and S
At 590, the value of the final ignition timing ADV is set in the register and the routine ends.

Therefore, when the slip ratio SL is small, the traction control is not performed, and the fuel cut is performed when the engine speed N exceeds the high speed fuel cut speed NMAX and when the vehicle speed VSP exceeds 180 km. As a result, over-rotation and over-vehicle speed are avoided, and safety is secured. Further, when knocking occurs, the basic ignition timing ADV0 is retarded by β to suppress knocking.

On the other hand, when it is determined in S490 that the slip ratio SL is large, the combustion control level CLn is set in S600 according to the slip rank SLn at that time. In this setting, as shown in FIG. 7, the correction value of the ignition timing is determined under the condition determined for each cylinder, and the ignition timing is the basic value ADV0 and ADV-5 and 10% for reducing the torque by 5%.
The ADV-10 that reduces the torque in Fig. 6 (a)
As shown in (b) and (c), each map MAP1, MAP
2 and MAP3 respectively. The larger the subscript n in the combustion control level CLn, the larger the reduction torque.

Next, in S610, the catalyst inlet temperature Tci is compared with the upper limit reference value STCin for determining catalyst deterioration, and S
Similarly, at 620, the inlet temperature time minutes value dTci is compared with the upper corner reference value SdTCin. If YES in S610, it is determined that the catalyst inlet temperature is high and catalyst burnout (deterioration) in the catalytic converter 12 is expected, and the process returns to S520 to prohibit correction for traction control by fuel cut (fuel cut correction). Ban). S610
If NO in step S620, the process proceeds to step S620. If YES in step S620, it is determined that catalyst burnout is expected to occur in step S520.
Return to.

On the other hand, if NO in S620, the process proceeds to S630, in which the catalyst bed temperature Tcc is compared with the upper corner reference value STccn for determining catalyst deterioration, and in S640, the catalyst bed temperature time differential value dTcc is also set as the upper limit. Compare with the reference value SdTccn. If YES in S630, it is determined that the catalyst bed temperature is high and catalyst burnout in the catalytic converter 12 is expected, and the process returns to S520 to prohibit correction for traction control by fuel cut. If NO in S630, the process proceeds to S640. If YES in S640, similarly, it is determined that catalyst burnout is expected, and the process returns to S520.

If NO in S640, the following S650-S are executed.
In the process of 700, it is sequentially determined whether or not it is in the operation region in which it is determined that the parameter corresponding to the engine load should be individually taken to reduce the correction level for traction control.

First, at S650, the engine speed N is set to the upper limit reference value S for determining the traction control control.
In comparison with HNn, in S660, the lower limit reference value SLNn
Compare with. If YES in S650, it is determined that catalyst deterioration in the catalytic converter 12 is expected, and S71
Go to 0. If NO, the process proceeds to S660 and step 66.
When 0 is YES, it is judged that an engine stall is expected and S
Proceed to 710.

On the other hand, if NO in S660, the flow proceeds to S670. In S670, the cooling water temperature TW is compared with the upper limit reference value SHTwn for determining the traction control control, and in S680, it is also compared with the lower limit reference value SLTwn.
If YES in S670, it is determined that overheating of the engine 1 is expected, and the process proceeds to S710. If NO, the process proceeds to S680, and if YES in S680, it is determined that the exhaust temperature is too lower than the enemy temperature and catalyst deterioration is expected, and the process proceeds to S710.

If NO in S680, the process proceeds to S690. In S6909, the basic injection amount Tp corresponding to the engine load is compared with the upper limit reference value SHTpn for determining the traction control control, and in S700, it is also compared with the lower limit reference value SLTpn. If YES in S690, it is determined that overheating of the engine 1 is expected, and S71
Go to 0. If NO in S690, proceed to S700, where S
If YES in 700, it is determined that engine stall is expected, and the process proceeds to S710. On the other hand, if NO in S700, S7
Go to 20.

In S710, the combustion control level C shown in FIG.
The level n of L is lowered to (n-1) to reduce the correction level of the traction control, and the process proceeds to S600. At S720, the catalyst bed temperature Tcc and the upper limit reference value ST
From the deviation from CCR, calculate the fuel cut correction amount TFC to be added to the injection amount of the cylinder that has been restarted from the rest by the following formula.

TFC = max {TFCR, KFCR × (STCCR-TCC)} This fuel cut correction amount TFC is the lower limit value of TFC looked up from the characteristic example shown in FIG. 8, and KFCR is a preset constant. Is. In S730, the combustion control level C
Fuel correction corresponding to L (correction in FIG. 7) is performed, and ignition timing for each cylinder is corrected in S740 (also correction in FIG. 7), and the process proceeds to S580.

FIG. 8 is a flow chart for realizing the characteristic example of FIG. 7, which is executed at each injection timing of each cylinder. If the control level is CL0 in S800, S810
Then, the counter CFC is cleared and the normal injection process is performed in S820. If the control level is not CL0 in S800, it is determined in S830 whether the control level is CL17. When the control level is CL17, that is, when the torque reduction rate is 100%, the counter CFC is cleared in S840, and the F / C process of stopping the fuel supply to all the cylinders is executed in S850.

On the other hand, if NO in S830, the counter CFC is incremented in S860, and in S870, the data is looked up from the characteristic example of FIG. 7 based on the control level CLn. Here, the description of FIG. 7 will be given. # 0 in the figure
6 is the value of the counter CFC and does not directly indicate the number of the cylinder. For example, if the control level is # 3 to # 6, as in the case of CL3 to CL5, # 0 is the first cylinder, and then # 1 is the second cylinder, # 2 is the third cylinder, and so on. After becoming the sixth cylinder, # 6 becomes the first cylinder, and the next # 0 becomes the second cylinder, and the value of the cylinder and the counter CFC is switched every cycle. "INJ" in Figure 7
Indicates that normal injection is executed for that cylinder, "CUT" indicates that injection is stopped, and "increase" indicates that the F / C correction increase TFC is added. The shaded area indicates that the counter value CFC does not exist. That is, CL6 ~
In 8, only # 0 to 3 are counted.

Returning to the flowchart of FIG. 8, in S880, it is determined whether or not the counter CFC has reached the maximum value obtained from the characteristic example of FIG.
Clear FC. Then, in S900, it is determined from the data looked up in S870 and the counter CFC whether or not the cylinder at the next injection timing is F / C. If YES, the process proceeds to S850. On the other hand, NO in S870.
If so, it is determined whether or not the amount is increased in S910,
If YES, in step S920, the injection pulse Ti is added with the f / c correction increase amount TFC, and the process proceeds to step S820.

According to the above processing, for example, the control level C
When the counter CFC is counted from the # 1 cylinder at L5, the first cylinder is initially set to F / C and the other cylinders are normally injected. And in the next step, the amount is increased to the first cylinder,
The second cylinder is F / C. Since the torque is reduced by 10% at the ignition timing, the total torque is reduced by 23%.

Therefore, when the slip ratio SL is large, the fuel cut is finely performed for each cylinder, and the ignition timing retard control is finely performed to reduce the torque and control the driving force of the vehicle. Here, the traction control has a great effect in preventing a slip on a road and a drift in a cornering, for example, and the safety of the vehicle is maintained.

Further, in this embodiment, unlike the conventional case where the flow rate of the intake air is throttled by the throttle valve, the torque reducing means is a fuel cut without delay, so that the responsiveness of the trunk control can be enhanced. In addition, it is possible to perform traction control with extremely precise (high accuracy) reduction of torque.

Further, in the present embodiment, since the above effect can be obtained by improving the existing engine combustion control system in software, the object can be achieved at a much lower cost than the conventional one. In addition, there are the following items as effects peculiar to the present embodiment.

In the present embodiment, if the catalyst inlet temperature exceeds a predetermined value when slip occurs, correction for fuel cut transition control is prohibited. Therefore, further increase in exhaust temperature is avoided to avoid the catalytic converter. The catalyst burnout (deterioration) in 12 can be prevented in advance. Further, not only the catalyst inlet temperature but also the inlet temperature time differential value dTci is used as a criterion for judgment, so that the catalyst burnout can be prevented more appropriately.

In addition, when the slip and the condition satisfying the normal fuel cut condition occur simultaneously, the slip control is prioritized by the determination of S450. Therefore, by giving priority to the slip control, it is possible to avoid the situation where the normal fuel cut acts as a disturbance to the transition control, and there is a unique effect that the performance of the traction control can be improved.

Further, since the correction level of the traction control is appropriately lowered when the engine 1 shifts to the predetermined traction control restriction state, the exhaust catalyst is prevented from deteriorating by avoiding an excessive rise or fall of the exhaust temperature. In addition, it is possible to prevent deterioration of the combustion state in the low rotation speed range, prevent engine stall, and avoid overheating of the engine 1.

Further, in the present embodiment, when the slip and the knocking occur at the same time, the slip control is prioritized by the determination of S490. Therefore, by giving priority to the slip control, the ignition timing is appropriately corrected for the traction control, and the knock control is also appropriately performed, so that the performance of the traction control can be improved.

When the knock control is prioritized, the retard control by the knock is gradually performed, the torque reducing effect is small, and the convergence response of the slip is deteriorated. On the other hand, according to the present embodiment, there is an effect that the convergence response of the slip is improved, and further, if the knock occurs, the knock can be suppressed.

When the catalyst bed temperature is low, the temperature of the catalyst can be maintained by increasing the increase value. The temperature distribution of all the cylinders is made uniform by sequentially replacing the cylinders to be deactivated, so that the durability of the engine can be improved.

[0059]

As described above, according to the vehicle driving force control apparatus of the present invention, the cylinders to be stopped are constantly replaced to make the internal temperature of the internal combustion engine uniform during the reduced cylinder operation. In addition to improving durability, by supplying fuel with an increased value according to the number of stopped cylinders only to cylinders that have returned from the fuel supply stopped state to the operating state, catalyst temperature drop is prevented and exhaust purification rate is increased. Prevent the decrease of.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a basic configuration of a vehicle driving force control device of the present invention.

FIG. 2 is a schematic configuration diagram of a vehicle driving force control device according to an embodiment.

FIG. 3 is a block diagram of a portion for performing ignition timing control of a control unit.

FIG. 4 is a flowchart showing a program for fuel injection control processing.

FIG. 5 is a flowchart showing mainly the first half of a program for driving force control processing.

FIG. 6 is a flow chart showing the latter half of the program of the driving force control processing. Is.

FIG. 7 is a flowchart showing a part of a program for driving force control processing.

FIG. 8 shows a map of ignition timing, (a) shows basic ignition timing ADV0, and (b) shows -5% torque ignition timing ADV-.
5 and (c) are diagrams showing a -10% torque ignition timing ADV-10, respectively.

FIG. 9 is a diagram showing a map of combustion control.

FIG. 10 is a flowchart showing a program of an injection control process executed at each injection timing of each cylinder.

FIG. 11 is a diagram showing an example of sequentially replacing stopped cylinders in the present invention.

FIG. 12 is a graph showing an example of the relationship between the number of stopped cylinders and the catalyst temperature and the relationship between the number of stopped cylinders and the increase value.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 3 ... Intake pipe, 6 ... Injector, 7 ... Spark plug, 8 ... Distributor, 9 ... Power transistor, 10 ... Ignition coil, 1
1 ... Exhaust pipe, 12 ... Catalytic converter, 13
... transmission, 15 ... air flow meter, 16 ... throttle valve, 17 ... throttle valve switch,
18 ... Crank angle sensor, 19 ... Knock sensor, 2
0 ... Water temperature sensor, 21 ... Oxygen sensor, 22 ... Vehicle speed sensor, 24 ... Neutral switch, 27 ... Catalyst inlet temperature sensor, 28 ... Catalyst bed temperature sensor, 40 ...
Control unit, 51 ... Operating state detecting means,
52 ... Ignition means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location F02D 17/04 B 7049-3G 41/04 330 G 8011-3G 41/22 330 S 8011-3G 45 / 00 345 G 7536-3G

Claims (2)

[Claims] 1. An operating state detecting means for detecting an operating state of an internal combustion engine having a plurality of cylinders and having an exhaust system provided with an exhaust catalyst, and a rotational speed of drive wheels driven by the internal combustion engine. Drive wheel rotation speed detection means, slip ratio calculation means for calculating the slip ratio of the drive wheel using the detected drive wheel rotation speed as one parameter, the calculated drive wheel slip ratio and the detected internal combustion A stopped cylinder number calculation means for calculating the number of cylinders for which fuel supply should be stopped based on the operating state of the engine, and a fuel supply stop for stopping fuel supply to a predetermined cylinder according to the calculation result of the stopped cylinder number calculation means. An output torque control unit that executes control and controls the output torque of the internal combustion engine; and a vehicle driving force control device that controls the driving force of the vehicle, wherein the fuel supply stop control is The output torque control means is configured so that the cylinders whose supply is stopped are sequentially replaced and executed, and the predetermined increase value is set only for the cylinders that have returned from the fuel supply stopped state to the operating state by the fuel supply stop control. To increase the fuel supply amount, the fuel amount increase control means for controlling the fuel supply amount to the internal combustion engine, and an increase amount for changing the increase amount value according to the number of reduced cylinders calculated by the stopped cylinder number calculation means. A vehicle driving force control device comprising: a value change control means; 2. A catalyst temperature detecting means for detecting the temperature of the exhaust catalyst, and a second increase value change control means for changing the increase value according to the catalyst temperature detected by the catalyst temperature detecting means. The vehicle driving force control device according to claim 1, further comprising: