JP2653801B2 - Engine idle control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides an engine that performs feedback control of an idle speed and performs learning control that stores the feedback control amount and reflects it in subsequent control. The present invention relates to an idle control device.

(Prior Art) Conventionally, when under a predetermined condition corresponding to an idling operation state, feedback control is performed so that an engine speed converges to a target speed, the feedback control amount is stored, and the stored value is stored. A device that is used at the time of starting the next feedback control is known. For example, in an apparatus disclosed in Japanese Patent Application Laid-Open No. 56-44431, a feedback control amount is increased or decreased according to a deviation between an engine speed and a target speed in a state corresponding to an idling operation. In addition to performing the control, the control amount is stored, and the learning control for sequentially updating the stored value is performed during the feedback control. When the feedback control is stopped, the control amount stored value is held and the open control is performed. Also, the stored value is used, and at the start of the next feedback control, the stored value becomes the initial value of the feedback control amount.

By the way, in this type of conventional apparatus, if the feedback control is performed, the storage and update of the feedback control amount are also performed along with the feedback control. In some cases, an inappropriate control amount is stored as the learning value reflected in the control of (1).

That is, the feedback control is performed under the condition assumed to be the idling operation. For example, in the case of an MT (manual transmission) vehicle, the condition in which the throttle valve is fully closed and the engine speed is equal to or less than a predetermined value in a neutral or clutch off state. Is performed when
The neutral clutch switch for detecting the neutral or clutch off state normally detects clutch off without disconnection even in a half clutch state. Therefore,
When the clutch is half-engaged in the process of shifting from the original idle operation state to the running state, feedback control and learning control for storing the control amount are performed if other conditions are satisfied. . In this case, it is desirable to execute feedback control in order to prevent the engine speed from dropping even in the half-clutch state. However, since the feedback control amount at this time greatly deviates from the original feedback control amount in the idle operation state, when the final value of the feedback control amount is set to the stored value when shifting to the open control from this state. When the feedback control is started again after returning to the idle operation state, the stored value becomes the initial value of the feedback control amount. As a result, the convergence of the engine speed deteriorates, and There is a problem that the rotation speed rises.

(Object of the Invention) In view of the above circumstances, the present invention prevents feedback from being performed inappropriately while performing feedback control when the clutch is half-engaged or the like. The present invention provides an engine idle control device capable of preventing the engine speed from rising at the time of transition.

(Structure of the Invention) As shown in the explanatory diagram of the structure of FIG. 1, the present invention performs feedback control so that the engine speed converges to the target speed when under predetermined conditions corresponding to the idling operation state. A control means A, and a learning storage means B for storing the feedback control amount obtained by the feedback control means A, wherein the value stored in the learning storage means B is used for starting the next feedback control after the feedback control is stopped. A variable state detecting means C for detecting a variable state of at least one of an engine speed and an intake charge amount, and a neutral or clutch off state. A neutral clutch-off detecting means D for detecting the I have. When the feedback control is performed by the feedback control means A and the neutral or clutch-off state is detected by the neutral clutch-off detection means E, the learning restriction means E includes the fluctuation state detection means C. When it is detected that at least one of the engine speed and the intake charge amount is in a fluctuating state, the feedback control amount by the learning control unit A is stored while the feedback control by the feedback control unit A is continued. Is prohibited. The control by the feedback control means A is performed by controlling the means for adjusting the intake air amount based on a comparison between the engine speed and the target speed.

According to this configuration, when the fluctuations in the engine speed and the intake charge amount are large, such as in the case where the vehicle is under the predetermined condition but in the half-clutch state, the feedback control is performed. The next feedback control is not affected.

(Embodiment) FIG. 2 shows an embodiment of the present invention.
Reference numeral 1 denotes an engine, and 2 denotes an intake passage. In the intake passage 2, an air cleaner 3, an air flow meter 4 for detecting an intake air amount, a throttle valve 5 which opens and closes in response to an accelerator operation, and an intake air A fuel injection valve 6 for injecting fuel into the passage 2 is provided.

The intake passage 2 is provided with a bypass passage 7 that bypasses the throttle valve 5 and communicates between the upstream side and the downstream side. The bypass passage 7 is provided with an ISC valve (ISC valve) that adjusts the flow rate of the passage 7. An idle speed control valve) 8 is provided, and the amount of intake air is adjusted by the ISC valve 8 during an idling operation or the like, whereby the idle speed is controlled.

The ISC valve 8 includes a control unit (ECU) 10
Is controlled by This control unit 10
A signal from a speed sensor 11 for detecting an engine speed,
A signal from a neutral clutch switch 12 (corresponding to a neutral clutch off detecting means D in FIG. 1) for detecting a neutral or clutch off state, a signal from a throttle opening sensor 13 for detecting the opening of the throttle valve 5, A signal from a water temperature sensor 14 for detecting a cooling water temperature of the engine and a signal from the air flow meter 4 are input to each.

The control unit 10 controls the ISC valve 8 based on a comparison between the engine speed detected by the speed sensor 11 and a target speed when under a predetermined condition corresponding to an idle operation state, Feedback control is performed so that the engine speed converges to the target speed. Further, a fluctuation state of at least one of the engine speed and the intake charge is detected, and more specifically, the fluctuation rates of the engine speed and the intake charge are checked, and these fluctuation rates are all equal to or lower than predetermined values. It is determined whether there is a stable state or at least one is in a fluctuation state larger than a predetermined value. When each of these fluctuation rates is equal to or less than a predetermined value, the feedback control amount at that time is stored as a learning value to be reflected in subsequent control. When the value is larger than the value, the feedback control amount at that time is not stored as the learning value. The control unit 10 constitutes the feedback control means A, the learning storage means B, the fluctuation state detecting means C and the learning control means E shown in FIG.

FIG. 3 schematically shows an example of feedback control performed under a predetermined condition corresponding to an idle operation state. In the example shown in this figure, first, the actual engine speed and the target speed are compared to obtain a rotational feedback correction value Qnfb of the intake air amount according to the deviation, and this rotational feedback correction value Qnfb, the basic intake air amount and the external intake air amount are calculated. The target intake air amount Qb is obtained by adding the correction value Ql according to the load. Furthermore, in order to correct the calculation and control errors and make the target intake air quantity Qb correspond to the actual intake air quantity Qa, the target intake air quantity Qb is compared with the actual intake air quantity Qa, and the flow rate feedback is made accordingly. A correction value Qqfb is obtained, and a final control amount is obtained by adding the flow rate feedback correction value Qqfb to a value obtained by subtracting a flow rate Qm of intake air passing through a portion other than the bypass passage (through a throttle valve) from the target intake air amount Qb, ISC based on this
The valve is controlled. In this embodiment, as will be described in detail in the flowchart below, the flow rate feedback correction value Qqfb is selected as a feedback control amount stored only when the variation rate of the engine speed and the variation rate of the intake air charge are small. I have.

FIG. 4 is a flowchart showing a specific example of control by the control unit 10. In this flowchart, first in step S ₁ to S _3, the water temperature detected by the water temperature sensor 14, writes each read the intake air quantity Qa detected by the engine speed Ne and the air flow meter 4 is detected by the rotational speed sensor 11. Next, in step S _4,
An intake charge amount CE is calculated based on the intake amount Qa, the engine speed Ne, the number of cylinders, and the like. In step S _5, the flow rate Qm of the intake air passing through the non-bypass passage 7, characteristic as shown in FIG. 5 is an index from a table which is determined in accordance with the example the water temperature. Further, in step S _6, it calculates a target intake air quantity Qb and _{Qb = Q 0 + Ql + Qsw} + Qdp + Qnfb. Here, Q ₀ is the basic intake air amount, Ql is correction value corresponding to the external load, Qsw correction value at the time of starting, Qdp is dashpot correction value at deceleration. Qnfb is a rotation feedback correction value as described above, and is increased or decreased according to a deviation between the actual rotation speed and the target rotation speed when the feedback control is executed, and is a constant value when the feedback control condition is not satisfied. (For example, 0).

Then, in step S _7, the flag ZIfb for determining feedback control execution condition is checked whether 1. In this case, the neutral clutch switch 12 is ON (a state in which the gear is not engaged), the throttle valve 5 is fully closed, the dashpot is not working, and the engine speed is a predetermined value. When each of the following conditions is satisfied, the flag ZIfb becomes 1 (feedback control execution condition is satisfied), and otherwise, the flag ZIfb is 0 (feedback control execution condition is not satisfied).
Becomes

If the flag ZIfb is 1, feedback control is performed. In this case, the coefficient value i is determined (step
Treatment of S ₈₎ and incremented (step S _9), once for each time the control of the feedback control execution conditions is executed three times, performs steps S ₁₀ ~ step S _12. In the step S ₁₀ to S _12, the actual by the processing of the air flow on the basis of a comparison between the target intake air amount Qb obtained in the actual intake air amount Qa and is detected in step S ₆ in meter 4, after surgery Step S ₂₅ The flow rate feedback correction value Qqfb, which is reflected in the intake air amount Qa, is increased or decreased. That is, in the case of [Qa ≧ Qb], [Qqfb ₁ −ΔQqfb] is changed to the current flow rate feedback correction value Q with respect to the previous flow rate feedback correction value Qqfb ₁ .
In the case of [Qa <Qb], [Qqfb ₁ + ΔQqfb] with respect to the previous flow rate feedback correction value Qqfb _{1 is} set as the current flow rate feedback correction value Qqfb. In this case, a value (+ Qqfb or -Qqfb) for increasing or decreasing the flow rate feedback correction value Qqfb
As shown in FIG. 6, Qqfb) is set to 0 if the absolute value of the difference (Qa−Qb) between the actual intake air amount Qa and the target intake air amount Qb is within a predetermined value or less. If [Qa-Qb] is positive outside, it is a negative value according to the difference, and if [Qa-Qb] is negative, it is a positive value according to the difference.

If step S ₁₀ to S ₁₂ is performed, the coefficient value i from the 1 (step S _13), the flow proceeds to step S _15. Incidentally, when the determination at step S ₇ of NO (when not in the feedback control execution condition) is the coefficient n as 1 (step S
With _14), the flow proceeds to step S ₁₅ through step S _13.

From step S ₁₅ to step S ₂₂ based on the detection of variation rate of the engine speed and the intake air charging amount, and stores the flow rate feedback correction value Qqfb only at the controlled conditions by controlling the learning conditions as the learning value processing Perform In this case, in this embodiment, in order to first check whether there is any abnormality in the control, a condition that the late duty value Td is in the range from the lower limit value Tmin to the upper limit value Tmax of the control, and [Qa-Q
It is determined whether or not the condition that [m] is 0 or more is satisfied (steps S ₁₅ and S ₁₆ ). When these determinations are YES, whether the condition that the variation rate (| ΔCE |) of the intake air charge amount CE is equal to or less than a predetermined value and the condition that the variation rate (| ΔNe |) of the engine speed is equal to or less than a predetermined value are satisfied. It determines whether (step S _17, S _18). If these determinations are also YES, this is further incremented until the count value n reaches 200 (steps S ₁₉ and S ₂₀ ). And when the count value n has reached 200, the flow rate feedback correction value Qqfb at that time as a stored value Qqfbm for learning in step S _21, then to 1 and resets the coefficient value n in step S _22. Step S ₁₅ ~
Or Izu determination of S ₁₈ is simply resets the coefficient value n when the NO.

Therefore, only when the condition of step S ₁₅ to S ₁₈ is followed by state is established, the control updates the above stored value Qqfbm each repeated 200 times, otherwise the update of the stored value Qqfbm Do not do.

Step S ₂₀ or step S following step S _{22
At 23} , it is checked whether the flag ZIfb is 1 or not.
Correction value the stored value Qqfbm in step S ₂₄ in the case of NO Qqfb
And That is, in the present embodiment, even during the open control, the correction is performed using the stored value Qqfbm obtained and held before that.

Following the determination or step S ₂₄ is YES in the step S _23, step S _25, obtains the [Qb-Qm + Qqfb] as a control value of the intake air flow rate of the bypass passage 7, depending on the value, as shown in FIG. 7 The control duty value Td for the ISC valve 8 is calculated according to the characteristic. Then, in step S _26,
By outputting the signal of the duty value Td, ISC
After the drive and control of the valve 8 are performed, the process returns.

According to the above-described control, when the operation state shifts from the idle operation state in which the feedback control is performed to the half-clutch state and the state in which the open control is performed to the state in which the feedback control is performed again, the engine rotation is stopped. The change in the number and the change in the flow rate feedback correction amount Qqfb are as shown in FIG.

That is, when the engine is in a normal idling operation state such as the throttle valve being fully closed with the neutral or clutch off, the engine speed is controlled to the target speed by feedback control and is almost stable. At this time, the flow rate feedback correction value Qqfb is successively corrected by the processing in the steps S ₁₀ to S _12, by the condition of step S ₁₅ to S ₁₉ is satisfied, every predetermined control circuit, at the time Stored value Qq with flow rate feedback correction value Qqfb
fbm is updated.

In this state, when the clutch is in a half-clutch state with the throttle fully closed, the load is gradually applied to the engine, causing the engine speed to decrease.On the other hand, feedback control is performed until the clutch is completely turned on. By repeating the control in the direction of increasing the intake air amount as the number decreases, the flow rate feedback correction amount Qqfb gradually becomes a large value, and a decrease in the engine speed is suppressed. However this time, the intake air charge amount CE varies greatly, variations in the engine speed when the feedback control is not completely follow also becomes larger than the normal idle, for the condition of step S _17, S ₁₈ is not satisfied The update of the stored value Qqfbm is prohibited.

Next, when the clutch is turned on and the vehicle shifts to a running state (for example, a so-called idle running state in which the throttle valve is substantially fully closed), the feedback control is stopped and the open control is performed. Qqfb
m is held and used as a correction value in open control. Further, when the clutch is turned off and the feedback control is restarted thereafter, the stored value Qqfbm is set as the initial value of the flow rate feedback correction amount Qqfb.

In this case, if the flow rate feedback correction value at the end of the feedback control in the half-clutch state is held as a stored value, as shown by the two-dot chain line in FIG. 8, the correction value becomes higher during the open control. , The engine speed rises more than necessary, making it difficult to run at low speeds.When the feedback control is restarted, the initial value of the flow rate feedback correction value becomes extremely high. The number is increased, and the convergence to the target rotational speed is deteriorated. On the other hand, according to the present invention, as shown by the solid line, the flow rate feedback correction value Qqfb in the stable state before the half-clutch state is set as the stored value Qqfbm, and this is the correction value held during the open control. Therefore, an increase in the engine speed is suppressed and low-speed running is enabled. When the feedback control is restarted, the stored value Qqfbm becomes an appropriate value as the initial value of the flow rate feedback correction value Qqfb, and the convergence to the target rotation speed is improved.

In the above embodiment, the flow rate feedback correction value Qq
Although the stored value of fb is used as a correction value at the time of open control, it may be used only as an initial value at the time of the next feedback control. Further, the feedback control does not necessarily need to be based on the rotation feedback correction value Qnfb and the flow rate feedback correction value Qqfb as in the above embodiment, but is performed by one type of feedback correction value corresponding to the deviation between the engine speed and the target speed. In this case, the feedback correction value may be stored as a learning value only under a stable condition.

(Effects of the Invention) As described above, the present invention performs the feedback control of the engine speed when under the predetermined operation condition corresponding to the idle operation state, and performs the feedback control during the feedback control.
When the engine speed and the intake charge are relatively stable when the neutral or clutch off state is detected, the feedback control amount is stored as a learning value. When the filling amount is changed, the learning is stopped while the feedback control is continued. For this reason, the feedback control is effectively performed, the learning effect is maintained while the learning effect is maintained, and the adverse effect due to the learning under unstable conditions such as in the half-clutch state is prevented, and the stable feedback control is performed. Is what you can do.

[Brief description of the drawings]

FIG. 1 is an explanatory view of the configuration of the present invention, FIG. 2 is a schematic diagram of the entire apparatus showing one embodiment of the present invention, FIG. 3 is a block diagram showing an outline of control during idling, and FIG. 5 is a flow chart showing a specific example, FIG. 5 is a characteristic diagram of the amount of intake air passing other than the bypass passage, FIG. 6 is a characteristic diagram of a value for increasing or decreasing the flow rate feedback correction value, FIG. 7 is a characteristic diagram of a control duty value,
FIG. 8 is a time chart showing changes in the engine speed and the flow rate feedback correction value according to the shift of the operating state. A: feedback control means, B: learning storage means,
C: fluctuation rate detection means, D: learning restriction means, 1 ... engine, 4 ... air flow meter, 7 ... bypass passage, 8 ... ISC valve, 10 ... control unit, 1
1 ... Rotation speed sensor.

Continuation of front page (56) References JP-A-60-17240 (JP, A) JP-A-61-55347 (JP, A) JP-A-61-55348 (JP, A) JP-A-60-128949 (JP) JP-A-61-25947 (JP, A) JP-A-62-276230 (JP, A)

Claims (1)

(57) [Claims] 1. A feedback control means for performing feedback control so that an engine speed converges to a target speed under a predetermined operating condition corresponding to an idling operation state, and a feedback control amount obtained by the feedback control means. An idle control device for an engine, comprising: a learning storage unit configured to store the feedback control value at the start of the next feedback control after the feedback control is stopped. Fluctuating state detecting means for detecting a fluctuating state of at least one of the engine speed and the intake charge amount; neutral clutch off detecting means for detecting a neutral or clutch off state; and feedback control by the feedback control means. Or When the neutral or clutch off state is detected by the neutral clutch off detecting means, and when at least one of the engine speed and the intake air charge is detected to be in the fluctuating state by the fluctuating state detecting means. An engine idling control device comprising: a learning restriction unit for prohibiting the learning storage unit from storing the feedback control amount while continuing the feedback control by the feedback control unit.