JP2003090240A - Control device for engine and its computor program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute reducing control of engine torque as linear as possible, while ensuring reliability of an exhaust system part by a delay of the ignition timing. SOLUTION: An engine control unit 30 comprises a control mode switching means 30a for switching a control mode so as to control the ignition timing by a first control mode limiting a maximum delay amount to a large value when an exhaust flow amount is a prescribed value or less and by a second control mode limiting the maximum delay amount to a small value relating to the first control mode when the exhaust flow amount is the prescribed value or more, and a prescribed amount setting means 30b for setting the prescribed amount of the control mode switching means 30a to a large value when a number of fuel cut cylinders is large relating to when the number is small. Accordingly, when the number of fuel cut cylinders is large with an exhaust temperature rise suppressed, by spreading a region of the first control mode limiting a maximum delay amount of the ignition timing to a large value, while suppressing a rise of exhaust temperature, a reducing control region of linear engine torque is spread.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control device, and more particularly to an engine control device for suppressing side slip and drive wheel slip of a vehicle.

[0002]

2. Description of the Related Art Conventionally, when excessive slip occurs in the drive wheels, or when the turning behavior of the vehicle largely deviates from the target behavior and there is an excessive understeering tendency, the engine torque is reduced to It is known to restore normal conditions from excessive slip and excessive understeer tendency. In the engine control device described above, in order to reduce the engine torque, so-called fuel cut is performed to retard the ignition timing or to stop the supply of fuel to a specific cylinder, but the ignition timing is excessively retarded. Then, there is a problem that the exhaust temperature rises due to the afterburning of the air-fuel mixture, and the durability of the exhaust system parts deteriorates.
Therefore, when the engine rotational speed is equal to or higher than a predetermined rotational speed, the exhaust gas flow rate is large, and the exhaust gas temperature is likely to be high, the retard control of the ignition timing is prohibited. (See, for example, JP-A-6-081689)

[0003]

However, if the retard amount of the ignition timing is limited as in the prior art, there is a problem that the linear engine torque reduction control cannot be performed. In other words, in order to respond to excessive slip or excessive understeer and reduce the engine torque only by the excessive amount, the engine torque reduction amount can be continuously reduced by combining the number of fuel cut cylinders and the ignition timing retard amount. However, if the retard of the ignition timing is prohibited as described above, the engine torque reduction amount cannot be finely adjusted by the retard of the ignition timing. Therefore, according to the above-mentioned prior art, when the engine speed shifts from the state below the predetermined number of revolutions to the predetermined number of revolutions or more, the ignition timing retard is suddenly released, the engine output suddenly changes, and the driver feels uncomfortable. There is a problem of feeling.

The present invention has been made in consideration of the above problems, and an object thereof is to control engine torque reduction as linearly as possible while ensuring reliability of exhaust system components due to ignition timing retardation. To perform.

[0005]

In order to achieve the above object, the present invention has the following means for solving the problem. That is, in the first configuration of the present invention, the traveling state detecting means for detecting a traveling state relating to the driving force of the vehicle, and, when a predetermined condition is detected by the traveling state detecting means, depending on the detected traveling state, An engine control means for controlling the retard amount of the ignition timing of the engine and the number of cylinders for which the fuel supply is cut, and an exhaust flow rate detecting means for detecting a value related to the exhaust flow rate of the engine. The engine control means includes the ignition timing based on the first control mode in which the maximum retardation amount of the ignition timing is limited to a large value when the exhaust flow rate detected by the exhaust flow rate detection means is less than or equal to a predetermined amount. Of the ignition timing is controlled, and when the exhaust flow rate detected by the exhaust flow rate detecting means is equal to or more than a predetermined amount, the maximum ignition retard amount of the ignition timing is smaller than that in the first control mode. Control mode switching means for switching the control mode so as to control the retard amount of the ignition timing based on the second control mode which is limited to The control mode switching means has a predetermined amount setting means for setting the predetermined amount to a large value. Only air is discharged from the fuel cut cylinder to the exhaust system. As the number of cylinders whose fuel supply is cut increases, the amount of air discharged to the exhaust system increases, and the rise in exhaust temperature is suppressed. According to the first configuration of the present invention, when the number of cylinders in which the fuel supply is cut is large and the rise in exhaust temperature is suppressed,
Since the first control mode execution region in which the maximum retard amount of the ignition timing is limited to a large value is expanded, the linear engine torque reduction control region can be expanded while suppressing the rise in exhaust temperature.

In a second configuration of the present invention, the engine control means includes an elapsed time measuring means for measuring an elapsed time after the running condition detecting means detects a predetermined condition and engine control is started, Until the elapsed time measured by the elapsed time measuring means reaches a predetermined time, regardless of the magnitude relationship between the exhaust flow rate detected by the exhaust flow rate detecting means and the predetermined amount, immediately before the control is started or the control is performed. The control mode fixing means fixes the control mode based on the exhaust flow rate detected by the exhaust flow rate detecting means at the start. When the engine torque reduction control is started, the operating state of the engine, such as the engine speed, greatly changes accordingly, and the operating state is the first for a predetermined period from the start of the engine torque reduction control until the operating state of the engine stabilizes. There is a problem that hunting occurs between the control mode and the second control mode. Second of the present invention
According to this configuration, the control mode is fixed to the control mode determined based on the exhaust flow rate detected immediately before the control starts or at the time when the control starts until the predetermined time elapses from the start of the engine torque reduction control. Timing control is executed.

In a third aspect of the present invention, the engine control means includes a transition state detecting means for detecting a transition from the first control mode to the second control mode, and the transition state detecting means for changing the first control mode from the first control mode. After the shift to the second control mode is detected, the control mode is fixed to the second control mode regardless of the magnitude relationship between the exhaust flow rate detected by the exhaust flow rate detection means and the predetermined amount. And fixing means. After the second control mode is once executed, the exhaust temperature is expected to rise, so the control mode is changed to the first control mode again, and the maximum ignition retard amount is increased. Then, there is a problem that the exhaust temperature rises and the reliability of the exhaust system parts is lowered. According to the third configuration of the present invention, since the control mode is fixed to the second control mode after the transition from the first control mode to the second control mode, the maximum retardation amount of the ignition timing becomes a small value. As a result, the exhaust temperature can be restrained from rising.

In the fourth structure of the present invention, the first embodiment is incorporated in an engine for a vehicle including at least a computer, a fuel injection valve and an ignition plug to detect a traveling state relating to a driving force of the vehicle. A procedure, a second procedure for detecting a value related to an engine exhaust flow rate, and a first procedure
A cylinder in which the ignition timing retard amount and the fuel supply are cut according to the detected running state when a predetermined condition is detected by the procedure and a state where the exhaust flow rate is less than or equal to the predetermined amount is detected by the second procedure. The third step of controlling the number of ignition timings and limiting the maximum retardation amount of the ignition timing to a large value, the first step detects a predetermined condition, and the second procedure detects a state in which the exhaust flow rate is equal to or more than a predetermined amount. The ignition timing retard amount and the number of cylinders for which fuel supply is cut are controlled according to the detected running state, and the maximum ignition timing retard amount is set when the exhaust flow rate is below a predetermined amount. Is set to a small value, and when the number of cylinders for which the fuel supply is cut is large, the fifth step is to set the predetermined amount in the third and fourth steps to a large value when the number of cylinders is small. Let the above engine execute Are you. According to the fourth configuration of the present invention, when the number of cylinders for which the fuel supply is cut is large, the control region in which the maximum retardation amount of the ignition timing is limited to a large value is expanded compared to when the number is small, The linear engine torque reduction control range can be expanded while suppressing the rise in exhaust temperature.

[0009]

According to the present invention, it is possible to execute the engine torque reduction control that is as linear as possible while ensuring the reliability of the exhaust system components due to the ignition timing retard.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram showing an input / output relationship with a brake control unit 20 for performing brake control, an engine control unit 30 for performing engine control, various sensors, and various actuators driven by various control units. . In this embodiment, as an engine controlled by the engine control unit 30, a fuel injection valve and an ignition plug are provided for each cylinder.
An example applied to a cylinder engine is shown. In FIG. 1, an ignition coil for controlling the ignition timing of the ignition plug is shown, and the illustration of the ignition plug is omitted.

The brake control unit 20 includes a wheel speed sensor 1 for detecting the wheel speed of the right front wheel, a wheel speed sensor 2 for detecting the wheel speed of the left front wheel, and a wheel speed of the right rear wheel. Wheel speed sensor 3, a wheel speed sensor 4 for detecting the wheel speed of the left rear wheel, a yaw rate sensor 5, a lateral acceleration sensor 6, and a steering angle sensor 7.
The detected value of is input.

The brake control unit 20 independently controls the brake actuators 8 provided corresponding to the wheels based on a computer program stored in a memory. A turning state determination means 20 for determining the turning state of the vehicle
a, a target braking force is calculated based on the turning state or the driving wheel slip state determined by the driving wheel slip determining unit 20b for determining the slip state of the driving wheel, the turning state determining unit 20a, or the driving wheel slip determining unit 20b. A required torque for calculating a required torque such that the driving force (torque) is reduced based on the turning state or the driving wheel slip state determined by the target braking force calculation means 20c and the turning state determination means 20a or the driving wheel slip determination means 20b. It is composed of a computing means 20d.
Reference numeral 9 is a lighting lamp that is turned on while the vehicle turning state control (hereinafter, DSC control) is being performed, and 10 is a lighting lamp that is turned on while the drive wheel slip state control (hereinafter, TCS control) is being performed.

The engine control unit 30 includes an engine speed sensor 11 for detecting the engine speed and an air flow sensor 12 for detecting the amount of air taken into the engine.
And the required torque calculated by the required torque calculating means 20d of the brake control unit 20 are input.

The engine control unit 30 independently controls the fuel injection valve 13 and the ignition coil 14 of each cylinder based on a computer program stored in a memory. When the torque down request (requested torque) calculated by the requested torque calculation means 20d of the control unit 20 is received, the intake charging efficiency (a value obtained by dividing the intake air amount by the engine speed, which is correlated with the exhaust gas flow rate, the engine 1 (Indicating the intake air amount per rotation) is larger than a predetermined value, and the control mode is set to a large guard value for the retard amount of the ignition timing based on the judgment result (this embodiment). Here, an example in which there is no guard is shown.) A first control mode and a second control mode in which the guard value of the ignition timing retard amount is set to a value smaller than that of the first control mode. Control mode switching means 30a for switching to either a predetermined amount setting means sets a predetermined amount of the control mode switching means 30a in accordance with the number of fuel cut cylinders 30
b, receiving the required torque from the brake control unit 20,
An elapsed time measuring unit 30c that measures an elapsed time from the start of the torque down control, and a predetermined amount and intake charging efficiency until the elapsed time measured by the elapsed time measuring unit 30c elapses a predetermined time. Control mode fixing means 30d for fixing the control mode based on the engine speed and the intake charging efficiency detected immediately before or at the start of the control regardless of the comparison result of the control mode from the first control mode to the second control mode. The transition state detecting means 30e for detecting that the control mode is changed to the second control mode from the first control mode is detected by the transition state detecting means 30e. Second control mode fixing means 30f for fixing the second control mode irrespective of the comparison result between the fixed amount and the intake charging efficiency, during control continuation in the first control mode Transition period measuring means for measuring a 3
0 g, when the control continuation time measured by the control continuation time measuring means 30 g reaches a predetermined upper limit time, the control mode is changed from the first control mode to the second control mode so that the retard amount of the ignition timing becomes small. Control mode changing means 30 for switching
h, an upper limit time setting unit 30i that makes the upper limit time in the control mode changing unit 30h longer in the second control mode than in the first control mode. Further, the engine control unit 30 calculates a base engine torque, which will be described later, and outputs the calculated base engine torque to the brake control unit 20.

The details of the control based on the control units 20 and 30 will be described below with reference to FIGS.

(DSC Control by Brake) In FIG. 2, first, at step 1, each wheel speed sensor 1 to 4 is detected.
Is detected, the detection value of the yaw rate sensor 5, the detection value of the lateral acceleration sensor 6, the detection value of the steering angle sensor 7, and the base engine torque calculated by the engine control unit 30 are input.

In step S2, each wheel speed sensor 1 to
Among the four detection values, the average value is calculated based on three detection values excluding the maximum value, and the average value is set as the vehicle body speed V. In step S3, the first target yaw rate value ω1 is calculated based on the vehicle speed V and the steering angle Θ. Specifically, the calculation is performed based on the following formula. ω1 = V × Θ × ((1-k × V × V) × L) V: vehicle speed Θ: steering angle k: vehicle body constant L: wheel base

In step S4, the second target yaw rate value ω2 is calculated based on the ratio of the vehicle body speed V to the lateral acceleration. In step S5, a larger value of the first target yaw rate value ω1 calculated in step S3 and the second target yaw rate value ω2 calculated in step S4 is set as the final target yaw rate ωt, and in step S6, A deviation Δω between the final target yaw rate ωt set in S4 and the actual yaw rate ωr detected by the yaw rate sensor 5 is calculated.

In step S7, it is determined whether or not the counterclockwise yaw rate is equal to or higher than a predetermined value and the vehicle is making a left turn. If YES is determined, the process proceeds to step S8. Then, in step S8, the deviation Δω calculated in step S6 is equal to the threshold value Chos.
When it is determined whether it is 1 (a positive value other than 0) or more, and it is determined to be YES, it can be determined that the vehicle is in the oversteer state while the vehicle is turning to the left. After FD is set to 1, the larger the Δω in step S10, the larger the turning outer wheel (right wheel).
Brake actuator 8 to increase the braking force of
To control.

If NO is determined in step S8, the process proceeds to step S11, and the deviation Δ calculated in step S6 is calculated.
It is determined whether ω is smaller than the threshold value Thus1 (negative value other than 0). If YES is determined in the step S11, it can be determined that the vehicle is in an understeer state while the vehicle is turning left. Therefore, in the step S12, the TCS control prohibition flag FD for prohibiting the TCS control is set to 1, and then in step S13, Δω is set. The brake actuator 8 is controlled so as to increase the braking force of the turning inner wheel (left wheel) as the value of ν increases. Note that the reason why the TCS control is prohibited in step S12 is to avoid interference with the TCS control.
Subsequently, in step S14, engine control is also executed, and in order to quickly return the understeer state during left turn to the normal state, the engine control unit 30 to be described later should increase the torque reduction amount as Δω increases.
The required torque after torque down is calculated based on the current base engine torque calculated by, for example, the engine torque down amount corresponding to Δω is subtracted from the current base engine torque, and the obtained required torque is controlled by the engine. Output to the unit 30.

If NO in step S7, the process proceeds to step S15. In step S15, it is determined whether the clockwise yaw rate is a predetermined value or more and the vehicle is turning right. If YES is determined in the step S15, it is determined whether or not the deviation Δω calculated in the step S6 is equal to or smaller than the threshold value Thhos2 (a negative value other than 0) in the step S16, and if YES is determined. Since it is possible to determine that the vehicle is in the oversteer state while the vehicle is turning to the right, the TC that prohibits the TCS control in step S17 as in steps S9 and S12
After the S control prohibition flag FD is set to 1, step S
The brake actuator 8 is controlled to increase the braking force of the turning outer wheel (left wheel) as the value of Δω increases in 18.

If NO is determined in step S16,
In step S19, it is determined whether the deviation Δω calculated in step S6 is larger than the threshold value Thos2 (a positive value other than 0). When YES is determined in step S19, it is possible to determine that the vehicle is in the understeer state while the vehicle is turning right. Therefore, in step S20, steps S9, S12, S
After the TCS control prohibition flag FD for prohibiting the TCS control is set to 1 as in 17, the brake actuator 8 is controlled to increase the braking force of the turning inner wheel (right wheel) as Δω increases in step S21. Continued, step S
In step 22, as in step S14, the required torque is calculated based on the current base engine torque in order to increase the torque reduction amount as Δω increases, and the calculated torque is output to the engine control unit 30.

If the result of the determination in any of steps S11, S15 and S19 is NO, the process proceeds to step S23 without performing DSC control, and the TCS control prohibition flag FD is reset to 0.

(TCS Control by Brake) In FIG. 3, in step S100, various sensor detection values are input as in step S1 of FIG.
In 1, the vehicle body speed V is calculated as in step S2 of FIG. In step S102, the right drive wheel and the vehicle speed V
The right drive wheel slip amount ΔVr is calculated on the basis of the difference between the left drive wheel slip amount and the vehicle body speed V in step S103. The slip ratio (1-vehicle body speed / driving wheel speed) may be used instead of the slip amount (driving wheel speed-vehicle body speed V).

Then, in step S104, step S
102 or the left drive wheel slip amount Vr calculated in step S103 or the left drive wheel slip amount Vr is the engine control TCS control start threshold VO.
If it is determined that the above is true, and if YES is determined in step S104, the process proceeds to step S105. Step S105
Then, from the state of the above-mentioned TCS control prohibition flag FD, DS
If it is determined to be NO during C control, and if NO is determined in step S106, the right drive wheel slip amount ΔVr and the left drive wheel slip amount Δ calculated in steps S102 and S103 are calculated.
Among Vr, the required torque is calculated based on the current base engine torque so that the larger the slip amount is, the larger the torque reduction amount is based on the larger slip amount, and the calculated torque is output to the engine control unit 30. The calculation of the required torque is the same as steps S14 and S22 in FIG.

In the following step S107, step S
102, right drive wheel slip amount Δ calculated in S103
It is determined whether or not one of Vr and the left drive wheel slip amount ΔVr is equal to or more than the brake control TCS control start threshold VB. The brake control TCS control start threshold value VB
Is set to a large value with respect to the engine control TCS control start threshold VO. If YES is determined in the step S107, the process proceeds to a step S108 and the step S
102, right drive wheel slip amount Δ calculated in S103
Of the Vr and the left drive wheel slip amount ΔVr, the brake actuator 8 is controlled because a larger slip amount applies a larger braking force to the drive wheel based on a larger slip amount. If NO is determined in the step S107,
Since the TCS control by the brake control is not necessary, the process returns without performing the process of step S108. Further, even when it is determined to be NO in step S104, the TCS control by the engine control and the TCS control by the brake control are performed.
Since there is no need for CS control, steps S106 and S10
Return without performing the process of 8. Incidentally, step S
When YES is determined in 105, the process returns without performing the TCS control in order to avoid interference with the DSC control.

(DSC and TCS Control by Engine) In FIG. 4, in step S200, the engine speed detected by the engine speed sensor and the intake air amount detected by the air flow sensor are input. In step S201, the brake control unit 100 causes the DSC to
It is determined whether or not there is a torque down request based on control or TCS control. That is, step S1 in FIG.
4, step S22 or step S1 in FIG.
It is determined whether or not the required torque amount calculated in 06 is output to the engine control unit 30.

If YES is determined in the step S201, calculation is performed in a step S202 based on the current engine operating state, for example, engine speed, intake air amount, fuel injection amount (encidin speed, intake air amount, etc.). Current engine torque (engine torque before execution of DSC control and TCS control) according to the ignition timing and the like. In step S203, the required torque output from the brake control unit 20 is divided by the gear ratio of the transmission to calculate the required engine torque. Subsequently, in step S204, the required torque down rate is calculated based on the base engine torque calculated in step S202 and the required engine torque calculated in step S203. The required torque reduction rate is calculated, for example, by the following formula. (Base engine torque-required torque) / base engine torque In step S205, it is determined whether or not the required torque down rate calculated in step S204 is smaller than the engine stall. Here, the engine guard limits the torque down control by the torque down control by the DSC control or the TCS control so as not to stall the engine, and is set to a smaller value as the engine speed is lower.

If YES in step S205, the flow advances to step S206 to set the number Nf of fuel cut cylinders according to the required torque reduction rate and execute fuel cut. Number of fuel cut cylinders N according to required torque reduction rate
f is set based on, for example, Table 1 below.

[Table 1] Then, in step S207, the retard amount of the ignition timing is set based on the required engine torque calculated in step S203 and the fuel cut cylinder number Nf set in step S206. That is, since the engine torque down amount is adjusted to the required torque down rate by the combination of the fuel cut cylinder number Nf and the ignition retard amount, the fuel cut cylinder number Nf is insufficient for the required torque down rate. The amount of retardation of the ignition timing is set in correspondence with the amount of torque reduction performed, and linear torque reduction control is performed.

In step S208, it is determined whether or not the control mode of the ignition timing control is the first control mode in which the guard of the ignition timing retard amount is limited to a large value (here, there is no guard). judge. The determination in step S208 will be described later in the description of FIGS. Step S2
If YES is determined in 08, the energization start and energization end timings for the ignition coil are controlled so that the ignition is executed based on the retard amount set in step S207.

When NO is determined in the step S208,
That is, when the second control mode is determined, step S
At 210, a guard value L for retarding the ignition timing is set. The guard value L is set to be smaller as the engine speed increases and to increase as the number of fuel cut cylinders increases. This is because the higher the engine speed, the higher the exhaust temperature, and the larger the number of fuel cut cylinders, the larger the amount of air discharged from the fuel cut cylinders to the exhaust passage, which suppresses the rise in the exhaust temperature. is there. Then, in step S211,
The retard amount set in step S207 is the step S21.
It is judged whether it is larger than the guard value L set at 0,
If YES is determined, in step S212, the retard amount is restricted to the guard value L, and then in step S209, the energization start and energization end timing of the ignition coil is controlled so that the ignition is executed based on the guard value L. To do. Step S2
If NO is determined in 11, the process proceeds to step S209, and the energization start and energization end timings of the ignition coil are controlled so that the ignition is executed based on the retard angle amount set in step S207. Incidentally, steps S201 and S205
When it is determined to be NO in step S213, normal engine control is performed.

Next, the control mode determination in step S208 of FIG. 4 will be described in detail with reference to FIGS. 5, in step S300, it is determined whether or not there is a torque down request from the brake control unit 20 based on DSC control or TCS control. When YES is determined in the step S300, it is determined whether or not the elapsed time after the start of the DSC control or the TCS control has exceeded a predetermined time in a step S301. When it is determined to be YES in step S301, the control mode is determined based on the control mode switching map shown in FIG. 6 in step S302.
The control mode switching map is set on the basis of the parameters of the engine speed and the intake charging efficiency, and is set so that the intake charging efficiency as a predetermined amount for mode switching becomes smaller as the engine speed becomes higher. There is. The predetermined amount is variable according to the number of fuel cut cylinders, and the predetermined amount is switched when the number of fuel cut cylinders is 0 cylinder and when the number of fuel cut cylinders is 3. In FIG. 6, a solid line SA indicates a predetermined amount when the number of fuel cut cylinders is set to 0 cylinder,
The wavy line SB indicates the predetermined amount when the number of fuel cut cylinders is set to three cylinders, and in the case of three cylinders, a large value is set as compared with the case of zero cylinders. Then, the calculated intake air charging efficiency is compared with the predetermined amount shown in FIG. 6, and as a result of the comparison,
The first control mode is determined when the intake charging efficiency is smaller than a predetermined amount, and the second control mode is determined when the intake charging efficiency is higher than the predetermined amount.

When NO is determined in step S301, the control mode is determined based on the engine speed and the intake charging efficiency detected immediately before or at the start of DSC control or TCS control in step S303.
In step S303, the control mode is fixed to the initially determined control mode until a predetermined time elapses after the control starts, even if the engine speed and the intake charging efficiency change from the control start.

In step S304, step S30
2, it is determined whether the control mode determined in S303 is the first control mode. When YES is determined in the step S304, it is determined in a step S305 that a first first control mode prohibition flag F1 described later is set to 1, that is, whether the first control mode prohibition state is set. If NO in step S305, step S306
Then, it is determined whether or not a second first control mode prohibition flag F2, which will be described later, is set to 1, that is, the first control mode prohibition state. If NO is determined in the step S306, it means that the first control mode is not prohibited,
In step S307, the control mode is finally set as the first control mode. The setting of the second first control mode prohibition flag F2 will be described later in the description of FIG.

Step S305 or step S30
If the result of the determination in any of 6 is YES, it means that the first control mode is in the prohibited state, and thus the step S
At 308, the control mode is set to the second control mode. If NO in step S304, step S30
At 9, it is determined whether the previous control mode was the first control mode. When YES is determined in step S309,
That is, when the transition from the first control mode to the second control mode is detected, the first first control mode prohibition flag F1 is set to 1 in step S310, and the subsequent step S30 is performed.
At 8, the control mode is set to the second control mode. If NO in step S309, step S3
At 08, the control mode is set to the second control mode.

When it is determined to be NO in step S300, both the first first control mode prohibition flag F1 and the second first control mode prohibition flag F2 are reset to 0 in step S311.

Next, the second first control mode inhibition flag F
The setting of 2 will be described based on FIG. 7. In step S400 of FIG. 7, it is determined whether the control mode is set to the first control mode. If YES is determined in step S400, the first control mode duration time counter T1 is set to the predetermined upper limit time T in step S401.
It is determined whether 10 has been reached. NO in step S401
If it is determined that the duration time T1 is incremented in step S402.

If YES is determined in the step S401, that is, when the control time is continued from the start of the DSC control or the TCS control to the predetermined upper limit time, the step S403 is performed.
Then, the second first control mode prohibition flag F2 is set to 1, and the duration counter T1 is reset to 0 in step S404. Then, in step S405, the second first
The control mode inhibition flag F2 is set to 1, and it is determined whether the inhibition time counter T2 after the inhibition of the first control mode has reached a predetermined value T20. Step S405
If NO is determined in step S406, the inhibition time counter T2 is counted up in step S406.

If YES is determined in the step S405, the second first control mode prohibition flag F2 is reset to 0 in a step S407, and the prohibition time counter T2 is reset to 0 in a step S408. Incidentally, step S40
If NO is determined in 0, the control mode is the second control mode. Therefore, in step S409, the control continuation counter T1 is reset to 0 and the process returns. That is, the second control mode is
Since the maximum retardation amount of the ignition timing is limited by the guard value L, and the exhaust temperature rise is originally suppressed by the limitation, it is not necessary to guard the control continuation time with the upper limit time.

As described above, according to this embodiment, the following effects can be obtained. (1) The predetermined amount for switching the control mode switching map is
Since the larger value SA is set as the number of fuel cut cylinders is increased, the first control mode in which the retard amount of the ignition timing is not guarded is expanded to the high intake charging efficiency side, and the linear engine torque down control region is set. Can be expanded. (2) During the period from the start of the DSC control or the TCS control until the predetermined time elapses, the control mode is fixed based on the engine speed and the intake charging efficiency detected immediately before or at the start of the control. It is possible to perform stable ignition timing control at the beginning of control or TCS control. (3) When the transition from the first control mode to the second control mode is detected, the control mode is fixed to the second control mode until the DSC control or the TCS control ends thereafter, so the ignition timing is the maximum. The amount of retard is limited to a small value,
The rise in exhaust temperature can be suppressed. (4) When the first control mode duration T for increasing the maximum retard amount of the ignition timing reaches a predetermined upper limit time T10,
After that, the first control mode is prohibited until the predetermined prohibition time T2 elapses, so that the rise in exhaust temperature can be suppressed. (5) When the second control mode in which the maximum retard amount of the ignition timing is reduced is executed, the control duration time is not limited by the upper limit time, so engine torque down control can be continued as much as possible.

In the present embodiment, an example in which the guard is not set for the maximum retardation amount of the ignition timing in the first control mode is shown, but the guard is set and the guard is set larger than that in the second control mode. You may make it set to a value. Further, in the present embodiment, an example in which the upper limit time of the control continuation time in the second control mode is not set is shown, but the upper limit time is set and the upper limit time is set to the first upper limit time.
The control mode may be set to be a long time. Further, in the present embodiment, an example has been shown in which the retard amount of the ignition timing is reduced by switching to the second control mode when the control duration of the first control mode reaches the upper limit time. As it is, the guard value L for the maximum retardation amount of the ignition timing in the first control mode may be changed to a small value. Further, in the present embodiment, the number of fuel cut cylinders is 0 when the predetermined amount of the control mode switching map is set.
Although the example in which the two-step switching is performed depending on the time of 3 and the time of 3, the predetermined amount may be linearly changed corresponding to the increase in the number of the fuel cut cylinders. Further, in the present embodiment, the example in which the exhaust flow rate is indirectly detected based on the intake charging efficiency has been described, but a flow rate sensor may be provided in the exhaust passage to directly detect the exhaust flow rate. Further, in the present embodiment, the example in which the intake charging efficiency is used as the value related to the exhaust gas flow rate is shown, but the air flow sensor 12 is used instead of the intake charging efficiency.
The intake air amount itself, the throttle opening or the intake pressure detected by the above may be used. Further, in the present embodiment, an example in which it is applied to a 4-cylinder engine is shown, but a V-type 6
It may be applied to an engine having other number of cylinders such as a cylinder engine. Further, in the present embodiment, an example in which the computer program for executing the control according to the present invention is stored in the memory of the engine control unit 30 and executed is described, but a storage medium (CD which is separate from the engine control unit 30 -ROM or the like) may be stored and executed.
Alternatively, the computer program may be obtained through a wireless communication means such as the Internet and stored in a rewritable ROM to be executed.

[Brief description of drawings]

FIG. 1 is a control system configuration diagram.

FIG. 2 is a flowchart showing brake DSC control contents.

FIG. 3 is a flowchart showing brake TCS control contents.

FIG. 4 is a flowchart showing engine control contents.

FIG. 5 is a flowchart showing control mode determination control contents.

FIG. 6 is a control mode switching map.

FIG. 7 is a flowchart showing the content of control for setting a second first control mode prohibition flag.

[Explanation of symbols]

1-4: Wheel speed sensor 5: Yaw rate sensor 6: Lateral acceleration sensor 7: Rudder angle sensor 30: Engine control unit 30a: control mode switching means 30b: predetermined amount setting means

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02D 43/00 F02D 43/00 301H F02P 5/15 F02P 5/15 F (72) Inventor Hideki Furuyama Hiroshima Prefecture 3-1, Shinchi, Fuchu-cho, Aki-gun (72) Inventor Makio Kondo 3-3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture F-term (reference) 3G022 AA04 CA04 DA02 GA05 GA06 GA19 3G084 AA03 BA13 BA17 CA04 DA05 DA17 EC03 FA05 FA07 FA32. 3G301 HA01 JA03 JA38 KA09 KA12 KA26 KB06 LB01 MA11 NE06 NE12 NE16 NE17 NE18 PA01Z PA17 PE01Z PF01Z

Claims (4)

[Claims] 1. A running state detecting means for detecting a running state relating to a driving force of a vehicle, and a predetermined condition detected by the running state detecting means,
An engine control device including an engine control means for controlling the retard amount of the ignition timing of the engine and the number of cylinders for which the fuel supply is cut according to the detected running state. An exhaust flow rate detecting means for detecting is provided, and the engine control means limits the maximum retardation amount of the ignition timing to a large value when the exhaust flow rate detected by the exhaust flow rate detecting means is less than or equal to a predetermined amount. The retard amount of the ignition timing is controlled based on the control mode, and when the exhaust flow rate detected by the exhaust flow rate detecting means is equal to or more than a predetermined amount, the maximum retard amount of the ignition timing with respect to the first control mode. The control mode switching means for switching the control mode so that the retard amount of the ignition timing is controlled based on the second control mode in which the fuel consumption is limited to a small value, and the number of cylinders in which the fuel supply is cut are large. Time, and a predetermined amount setting means for setting a large value to a predetermined amount of the control mode switching means with respect to time less, the engine control system, characterized in that. 2. The engine control means, an elapsed time measuring means for measuring an elapsed time from when the running state detecting means detects a predetermined condition and the control is started, and the elapsed time measuring means. The exhaust flow rate detection immediately before or at the start of the control regardless of the magnitude relationship between the exhaust flow rate detected by the exhaust flow rate detection means and the predetermined amount until the predetermined elapsed time elapses. The control device for an engine according to claim 1, further comprising: a control mode fixing unit that fixes the control mode based on the exhaust gas flow rate detected by the unit. 3. The engine control means comprises a transition state detection means for detecting transition from the first control mode to the second control mode, and transition from the first control mode to the second control mode by the transition state detection means. After the detection is performed, the control mode is fixed to the second control mode regardless of the magnitude relationship between the exhaust flow rate detected by the exhaust flow rate detection means and the predetermined amount.
The control device for encidin according to claim 1, further comprising a control mode fixing unit. 4. A first procedure for incorporating a vehicle engine control device including at least a computer, a fuel injection valve and an ignition plug into a vehicle engine to detect a traveling state related to a driving force of the vehicle, and an engine exhaust. When a predetermined condition is detected by the second procedure for detecting a value related to the flow rate and the first procedure, and the state in which the exhaust flow rate is less than or equal to the predetermined amount is detected by the second procedure, the detected traveling state is set. Accordingly, the ignition timing retard amount and the number of cylinders for which the fuel supply is cut are controlled, and a predetermined condition is detected by the third procedure of limiting the maximum ignition timing retard amount to a large value and the first procedure. Further, when the state where the exhaust flow rate is equal to or more than the predetermined amount is detected by the second procedure, the retard amount of the ignition timing and the number of cylinders for which the fuel supply is cut are controlled according to the detected running state, and the exhaust gas is controlled. Flow When the amount is less than a predetermined amount, the fourth procedure for limiting the maximum ignition retard amount to a small value, and when the number of cylinders whose fuel supply is cut is large, the third procedure and A computer program for causing a control device of the engine to execute a fifth step of setting a predetermined amount to a large value in the four steps.