JP2605371B2 - Control device for internal combustion engine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a control device for an internal combustion engine for stabilizing the engine speed accurately under idling conditions of the internal combustion engine.

[Conventional technology]

In this type of the related art, the intake air amount and the ignition timing of the internal combustion engine (engine) are simultaneously controlled such that the engine speed under idling conditions matches the target speed.

However, in such a case, for example, in FIG. 5, when the target rotational speed suddenly changes from 650 rpm to 750 rpm,
Since the ignition timing control has a sufficiently fast response to the air flow rate control, the ignition timing is immediately corrected from A to B to the upper limit value of the practical ignition timing range, and thereafter, the air amount is corrected from B to C. Therefore, there is a problem that the correction value of the ignition timing quickly reaches the limit value, and the effect of the ignition timing control cannot be sufficiently obtained with respect to the subsequent rotation speed fluctuation.

Conventionally, in order to solve this problem, there has been proposed an apparatus in which only the intake air amount is corrected and controlled until the target rotation speed is approached, and the ignition timing is corrected and controlled from the time when the target rotation speed is approached ( For example, JP-A-61-87976).

[Problems to be solved by the invention]

However, in this case, since the ignition timing correction control is not performed until the rotation speed approaches the target rotation speed, there is a problem that the response is poor.

Therefore, an object of the present invention is to stabilize the engine speed to the target speed accurately even when the target speed rapidly changes, without impairing the normal responsiveness.

[Means for solving the problem]

Therefore, as shown in FIG. 1, the present invention relates to a control device for an internal combustion engine that controls the amount of air drawn into the internal combustion engine and the ignition timing in order to maintain the engine speed at a constant value under specific operating conditions of the internal combustion engine. An engine speed detecting means for detecting the engine speed, and an air amount control means for controlling the air amount so as to reduce a deviation between the engine speed and the target speed detected by the engine speed detecting means, Ignition timing control means for controlling the ignition timing within a predetermined correction range so as to reduce the deviation between the engine speed detected by the engine speed detection means and the target engine speed, and Auxiliary air amount control means for adjusting the air amount in a direction to reduce the correction amount of the ignition timing even after the ignition timing has reached, and the ignition timing control means detects the target rotation speed and the target rotation speed in the previous ignition timing correction amount. Speed And an integral term calculating means for calculating a current ignition timing correction amount by adding a predetermined value according to the deviation from the auxiliary air amount control means. Outside the control range narrower than the predetermined correction range, when the ignition timing correction amount is positive, the air amount is increased, and when the ignition timing correction amount is negative, the air amount increasing / decreasing means decreases the air amount. And a control device for an internal combustion engine.

[Action]

Thus, the intake air amount is controlled by the air amount control means so as to reduce the deviation between the engine speed detected by the engine speed detection means and the target speed, and the engine speed detected by the engine speed detection means is reduced. The ignition timing is controlled within a predetermined correction range by ignition timing control means so as to reduce the deviation between the ignition timing and the target rotation speed. Further, even after the engine speed reaches the target speed by these controls, the air amount is adjusted by the auxiliary air amount control means, and the amount of correction of the ignition timing by the ignition timing control means is reduced.

Further, the ignition timing control means is configured to include integral term correction means, and a predetermined value corresponding to the deviation between the target rotation speed and the detected rotation speed is added to the previous ignition timing correction amount to obtain the current ignition timing correction amount. Further, the auxiliary air amount control means is constituted by an air amount increasing / decreasing means, and the ignition timing correction amount calculated by the integral term calculating means is outside the control range narrower than the predetermined correction range. When the timing correction amount is positive, the air amount is increased, and when the ignition timing correction amount is negative, the air amount is decreased.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Second
The figure shows the basic configuration of the present invention. The crank angle sensor 1 sends a pulse signal having a frequency proportional to the rotation speed of the engine to an engine control device (hereinafter abbreviated as ECU) 2. ECU2
Includes a microprocessor, calculates a fuel injection amount, an ignition timing, an amount of bypass air at the time of idling, and the like according to an operation state of the engine, and supplies a signal to each output device. (Only the one related to idle control is shown in FIG. 2.) The ignition timing signal is output to the igniter 3 to generate a high voltage in the ignition coil 4 and distribute it to the ignition plug 6 of each cylinder by the distributor 5. . Further, the bypass air quantity is adjusted by controlling the opening degree of the ISC I dle S peed C ontrol) valve.

FIGS. 3 and 4 show the control contents in the form of flowcharts. First, the basic arithmetic expression of the ignition timing θ _ig is shown below.

θ _ig = θ _BASE + θ _isc (1) where θ _BASE is a basic advance angle and θ _isc is an idle correction advance angle. In the equation (1), a guard value of −θ _L <θ _isc + θ _L (2) is provided as a practical ignition timing correction range. Here, θ _L is preferably about 10 °. Further, the idle correction advance angle is composed of three elements (proportional term θ _{p (isc)} , integral term θ _{i (isc)} , and derivative term θ _{D (isc)} ).

_{θ isc = θ p (isc)} + θ i (isc) + θ D (isc) ...... (3) As appropriate control range of the compensation advance _{-θ CT <θ i (isc)} <θ CT ...... (4) Is provided. Here, θ _CT is preferably smaller than θ _L , for example, about 3 °. Next, a description will be given below based on the flowcharts of FIGS. In FIG.
First, the control of θ _isc will be described. The basic advance value θ _BASE is calculated based on the rotation speed, the air flow rate, various sensor signals, and the like by the rotation angle interruption (step S1). Next, it is determined whether the idle feedback condition is satisfied (step
S2), the target rotation speed N _eo when you are satisfied, the deviation .DELTA.N _e between the measured speed N _e calculated (step S3), and proportional correction theta _p corresponding to the proportional term correction amount than the value (.DELTA.N _{e (isc)} =
K _p · ΔN _e), (integration correction corresponding to the integrated value up to now from the past ΔN _e θ _{i (isc)} integration term correction component = previous θ _{i (isc)} +
K _i · ΔN _e ) and the differential term correction (the differential correction θ _{D (isc)} according to the change in ΔN _e = K _D (previous ΔN _e −current Δ
N _e)) to be respectively calculated (step S4 to S6). Then, in step S7, the sum of each term is _calculated as θ _isc = θ _{p (isc)} + θ
_{It is} calculated by _{i (isc)} + θ _{D (isc)} . In steps S8 to S11, the ignition timing θ _isc serves as a guard to prevent the ignition timing from being excessively advanced or retarded. When it is determined in step S2 that the feedback condition is not satisfied, the process proceeds to step S12, and _{θisc is set} to 0. Final step S1
3, by adding the theta and _BASE and theta _isc obtained above finding a final ignition timing theta _ig.

Next, control of the ISC valve 7 will be described with reference to FIG. 4 (this embodiment will be described below with an example in which the valve opening is controlled by controlling the duty of the energization time of the ISC valve 7). . If in step 21 the idle condition is established, in accordance with the difference .DELTA.N _e in step S22, the program proceeds to S23 actual speed N _e and the target rotational speed N _eo IS
Calculating the basic duty ratio of the C valve 7 (D _o). Next, in step S24, it is determined whether or not the previous θ _{i (isc)} (integration correction amount) is within a predetermined value range (± θ _CT ). If out of range storing ΔD or -ΔD correction term D _c in accordance with the sign of the value the program proceeds to step S25 to S27. Further, in step 24 θ _{i (isc)} is when the is within a predetermined value range is 0 to D _c proceeds to step S28. Also step
In S29 the cumulative correction term D of the previous 'to _c by adding D _c current cumulative correction term D' seek or _c. The final step S30 in by adding the D _o and D _'c obtained duty ratio of the final ISC valve 7 (D). If the idle feedback condition is not satisfied in step S21, the process ends without doing anything.

Here, it goes without saying that the target rotation speed Neo changes in accordance with ON / OFF of an electric load such as an air conditioner and the temperature of the engine cooling water.

Further, a change state of the ignition timing and the air amount in this embodiment will be described with reference to FIG. Target rotation speed from 650 rpm
In the case of a sudden change to 750 rpm, since the ignition timing control has a sufficiently high response to the air flow rate control, the ignition timing is immediately corrected from A to B to the upper limit of the practical ignition timing range, and thereafter, the air amount is changed from B to B. C, but the engine speed Ne
Even after reaching the target rotation speed of 750 rpm, the air amount is increased by a predetermined amount in steps S24 to S29 in FIG. 4 until the integral term θi (isc) of the ignition timing falls within the control value range. with increasing air volume, the ignition timing by the flowchart of FIG. 3 is controlled to gradually retard side basic advance angle theta _bASE
, And finally moves to D.

Thus, the ignition timing can be set near the center of the control range, and the effect of the subsequent ignition timing control can be sufficiently obtained.

〔The invention's effect〕

As described above, the present invention has an excellent effect that achievement of the target value control of the engine speed can be satisfactorily realized by an appropriate combination of the intake air amount and the ignition timing.

[Brief description of the drawings]

1 is a diagram corresponding to the claims of the present invention, FIG. 2 is a block diagram showing an embodiment of the apparatus of the present invention, FIGS. 3 and 4 are flowcharts for explaining the operation of the apparatus shown in FIG.
FIG. 5 is an air amount-ignition timing characteristic diagram in the apparatus shown in FIG. 1 ... crank angle sensor, 2 ... engine control device, 3 ... igniter, 7 ... ISC valve.

Claims (1)

(57) [Claims] An internal combustion engine control device for controlling the amount of air taken into the internal combustion engine and the ignition timing to maintain the engine speed at a constant value under specific operating conditions of the internal combustion engine. Engine speed detecting means, air amount control means for controlling the air amount so as to reduce the deviation between the engine speed detected by the engine speed detecting means and the target speed, and the engine speed detecting means Ignition timing control means for controlling the ignition timing within a predetermined correction range so as to reduce the deviation between the engine rotation speed and the target rotation speed detected by the above, and even after the engine rotation speed reaches the target rotation speed, Auxiliary air amount control means for adjusting the air amount in a direction to decrease the absolute value of the correction amount of the ignition timing, wherein the ignition timing control means adjusts the target rotation speed and the detected rotation speed to the previous ignition timing correction amount. According to the deviation of An integral term calculating means for calculating the current ignition timing correction amount by adding the predetermined value.
The auxiliary air amount control means increases the air amount when the ignition timing correction amount calculated by the integration term calculation means is outside a control range narrower than the predetermined correction range and the ignition timing correction amount is positive. A control device for an internal combustion engine comprising an air amount increasing / decreasing means for decreasing the air amount when the ignition timing correction amount is negative.