JPH04134155A - Idling speed controller for engine - Google Patents

Abstract

PURPOSE:To improve the extent of stability at the time of idle running by calculating a moderating engine speed made up of moderating the actual speed of an engine, and when a deviation between the actual speed and the moderating speed becomes less than the specified value, starting the feedback control of idling speed. CONSTITUTION:During engine driving, engine speed is detected by a speed detecting means 36, and when it has come to an idle running state, a moderating engine speed made up of moderating the actual speed is calculated by a speed signal of a speed detecting means 36 by a speed calculating means 62. In addition, a deviation between the actual speed and the moderating speed is detected by a deviation detecting means 63, and when this deviation becomes less than the specified value, a feedback control means 61 is made to start the feedback control by a feedback starting means 64, thereby controlling the idling speed to be turned to the desired engine speed. In brief, after the idling speed is stabilized, the feedback control is started. With this constitution, such a fact that idling speed might be large and thereby undershot is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an idle speed control device that performs feedback control of the idle speed of an engine, and particularly relates to a measure for starting feedback control.

(Prior Art) In general, an engine idle speed control device is provided with a bypass passage for bypassing a throttle valve in an intake passage, as disclosed in Japanese Patent Application Laid-Open No. 72319/1983. While a control valve is provided, the engine speed is detected, the deviation between the engine speed at idle and the target rotation speed is calculated, and the control valve is opened and closed in response to this deviation to control the bypass air flow rate. There are some that use feedback control to control the idle speed.

(Problem to be solved by the invention) In the engine idle speed control device described above,
Feedback control during idling is started when the engine speed drops to a predetermined speed or less, which is slightly higher than the target speed, after the throttle valve is fully closed.

However, as shown in Fig. 7, in this case, the engine speed ne during idling often decreases from a high speed region such as during deceleration, and when the engine speed reaches a predetermined speed α, feedback control is started. Then, the engine speed ne becomes larger than the target speed and undershoot (7th
(see Figure A), there was a problem of hunting. In other words, in a state where the engine speed ne is rapidly decreasing, the feedback control signal further instructs the engine speed to decrease, so the feedback correction amount shown in FIG. 881 is added, and the engine speed ne becomes the target speed. This will result in a greater decline. Then, as the amount of undershoot on the negative side increases, the amount of feedback correction on the positive side to return the engine speed ne increases (see B2 in Figure 8), and as a result, the engine speed ne may hunt. become.

Further, as shown by the broken line C in FIG. 7, there is a problem in that feedback control is not performed forever unless the engine speed ne during idling decreases to a predetermined speed α.

The present invention has been made in view of the above, and aims to prevent the idle rotation speed from greatly undershooting and hunting, and to ensure that feedback control is performed. It is.

(Means for Solving the Problems) In order to achieve the above object, the means taken by the present invention are as follows:
Feedback control is started when the deviation between the actual engine speed and the smoothed engine speed becomes less than or equal to a predetermined value.

Specifically, as shown in FIG. 1, first, the rotation speed detection means 36 detects the rotation speed of the engine, and the rotation speed detection means 360 receives the rotation speed signal and adjusts the engine speed so that the idle speed becomes the target rotation speed. The present invention is based on an engine idle speed control device equipped with a feedback control means 61 that performs feedback control.

Then, receiving the rotation speed signal from the rotation speed detection means 36,
An annealed rotational speed calculation means 62 is provided for calculating an annealed rotational speed by annealing the actual rotational speed.

Furthermore, deviation detection means 63 is provided which receives the rotational speed signal from the rotational speed detection means 36 and the calculated signal from the smoothed rotational speed calculation means 62 and detects the deviation between the actual rotational speed and the smoothed rotational speed. In addition, feedback starting means 64 is provided which receives the deviation signal from the deviation detection means 63 and starts feedback control of the feedback control means 61 when the deviation becomes less than a predetermined value.

(Function) With the above configuration, in the present invention, the rotation speed detection means 36 detects the rotation speed of the engine. Then, when the engine is in an idling state, the annealed rotational speed calculation means 62 calculates an annealed rotational speed by annealing the actual rotational speed from the rotational speed signal from the rotational speed detection means 36.

Subsequently, the deviation detection means 63 detects the rotation speed detection means 36.
The deviation between the actual rotational speed and the smoothed rotational speed is detected from the rotational speed signal of and the calculation signal of the smoothed rotational speed calculation means 62. When the deviation between the actual rotation speed and the smoothed rotation speed becomes equal to or less than a predetermined value, the feedback start means 64 causes the feedback control means 61 to start feedback control, and the feedback control means 61 feedback-controls the idle rotation speed. , controls the idle rotation speed to the target rotation speed.

In other words, feedback control is started after the idle speed becomes stable.

(Effects of the Invention) Therefore, according to the present invention, an annealed engine speed is calculated by annealing the actual engine speed, and when the deviation between the actual engine speed and the annealed engine speed becomes equal to or less than a predetermined value, the engine idles. Since the feedback control of the rotation speed is started, the idle rotation speed is feedback-controlled after the idle rotation speed has stabilized, so that the idle rotation speed does not significantly undershoot with respect to the target rotation speed. , and hunting can be prevented. As a result, stability during idling can be significantly improved.

In addition, even when the idle speed is high, once the idle speed is stabilized, feedback control can be performed reliably, so the idle speed can be reliably controlled to the target speed. Idle return failure can be prevented.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 2 shows an engine equipped with an idle speed control device according to an embodiment of the present invention. In the figure, 1 is an engine, and this engine 1 includes a cylinder block 3 forming a cylinder 2, a cylinder head 4 joined to the upper surface of the cylinder block 3, and a piston 5 that reciprocates within the cylinder 2. The cylinder 2 has a combustion chamber 6 defined by the lower surface of the cylinder head 4 and the top surface of the piston 5.
is formed. A spark plug 7 is provided facing the combustion chamber 6. 8 is an ignition coil that generates a secondary voltage for ignition; 9 is a distributor that is drivingly connected to the output shaft of the engine and connected to the ignition plug 7 and ignition coil 8; The power is distributed to the spark plugs 7 of the cylinders undergoing the combustion stroke.

An intake passage 10 is connected to the combustion chamber 6, and an intake valve 11 is provided at the opening to the combustion chamber 6 to introduce intake air into the combustion chamber 6 at a predetermined timing. A throttle valve 12 for adjusting the amount of intake air, a surge tank 13 for absorbing intake pulsation, and an injector 14 for injecting and supplying fuel are arranged in this intake passage 10 in order from upstream. Furthermore, the intake passage 1
0 is provided with a bypass passage 15 that bypasses the throttle valve 12, and an ISC valve 16 that adjusts the flow rate of bypass air flowing through the bypass passage 15 is disposed in the middle of this bypass passage 15. The ISC valve 16 is a duty-driven solenoid valve, which performs duty control according to the required flow rate of bypass air, and by adjusting the flow rate of bypass air, the amount of intake air to the engine 1 is adjusted, and the amount of air taken into the engine 1 is adjusted during idling operation. In some cases, feedback control of engine speed is performed.

Further, an exhaust passage 17 is connected to the combustion chamber 6, and an exhaust valve 18 is provided at the opening to the combustion chamber, so that exhaust gas is discharged from the combustion chamber 6 at a predetermined timing. This exhaust passage 17 is provided with a catalyst 19 for purifying exhaust gas.

The operations of the ignition coil 8, injector 14, and ISC valve 16 are controlled by a control unit 50 containing a CPU.

Furthermore, in FIG. 2, 31 is a hot wire type air flow sensor that detects the amount of intake air, 32 is an idle switch that outputs an ON signal when the throttle valve 12 is fully opened,
33 is a throttle position sensor that detects the opening degree of the throttle valve 12; 34 is a water temperature sensor that detects the engine cooling water temperature inside the water jacket 3a in the cylinder block 3; and 35 is a catalyst 1 in the exhaust passage 17.
A sensor 02 is arranged upstream of the engine 9 and detects the oxygen concentration in the exhaust gas, and a sensor 36 is a rotation speed sensor serving as a rotation speed detection means for detecting the engine rotation speed by detecting the crank angle.

The output signals of the sensors and switches 31 to 36 are input to the control unit 50.

Furthermore, the control unit 50 includes a feedback control means for controlling the ISO valve 16 to feedback-control the idle rotation speed, and an annealed rotation speed calculation means for calculating an annealed rotation speed by annealing the actual rotation speed. The smoothing deviation detection means detects the deviation between the actual rotational speed and the smoothed rotational speed, and the feedback starting means starts feedback control when the deviation becomes a predetermined value or less.

Next, idle rotation speed control by the control unit 50 will be explained based on the control flow shown in FIG. 3.

First, start and use step STI to set rotation speed sensor 3.
Read the rotation speed ne of engine 1 from 6 and proceed to step S.
At T2, the coolant temperature th of the engine 1 is detected by the water temperature sensor 34.
Read the engine speed n in step ST3.
A target engine speed no during idling is set from e and engine coolant temperature thw, and in step ST4, IS, which is the intake air amount during idling, is set from the engine coolant temperature thV.
Set CSC pace Qb.

Next, the process moves to step ST5, and the idle switch 32 is turned on.
It is determined from the signal whether the throttle valve 12 is fully closed or not. If the throttle valve 12 is open during driving, the process moves to step ST6, and the delay counter C1fb for feedback control, which will be described later, is set to a predetermined value. K jfb is set, and the process moves to step ST7, where the intake air amount feedback correction amount Qfb is set to zero. After that, step ST
8, the total income air ff is calculated from the ISCSC pace Qb and the feedback correction amount Qf'b (zero in the current routine).
1Qt, move to step ST9, and calculate the total revenue air Qt.
After calculating the duty of the ISC valve 16 corresponding to Qt, the process moves to step 5TIO, sets the drive amount of the ISC valve 16 to the calculated duty, and returns.

On the other hand, when the throttle valve 12 is fully closed due to deceleration and the idle state is reached, the determination in step ST5 becomes YES, and the process moves to step STI 1, where the delay counter C1fb set in step ST6 is set to the set value. It is determined whether or not it is Kirb, and since they match at the beginning of the idle time, the process moves to step 5T12.

In this step 5T12, the initial rounded rotational speed ned during idling is set to the actual rotational speed ne, and the process moves to step STI 3, where the smoothed rotational speed ned is calculated.

However, since the previous actual rotation speed ne is not available for the first time during idling, the process directly proceeds to step 5T14, where the delay counter Cif'b is subtracted by 1, and the process proceeds to step STI 5, where it is determined whether this delay counter Cjrb is zero or not. It is determined whether or not. Then, the process moves to step ST8 until the delay counter ctrb becomes zero, and the ISC valve 16 remains as the feedback correction amount Qrb is zero as described above.
is duty-controlled. In other words, since the delay counter C1fb has a small deviation from the actual rotational speed ne at the initial stage of calculation of the smoothed rotational speed ned, it waits until this deviation increases once.

After that, the above steps ST1 to ST5.5T11 to 5T
Repeat the operations of I5 and ST8 to 5TIO, and at that time,
The determination in step 5T11 becomes NO from now on, and step 5
Skipping T12, in step 5713, an annealed rotational speed ned obtained by annealing the actual rotational speed ne detected by the rotational speed sensor 36 is sequentially calculated based on the following formula.

nedi ma meeting ne ±(1-α) enedi-
1-... ■α constant number (0 × α × 1) In other words, the rounded rotation speed at the previous sampling ned1-
1 and the actual rotational speed ne sampled this time, the smoothed rotational speed nedi at the time of sampling this time is calculated.

Thereafter, when the delay counter ctrb becomes zero, the determination at step 5TI5 becomes YES, and the step 5
Proceeding to T16, the deviation dne (l ned − ne l ) between the actual rotation speed ne and the smoothed rotation speed ned is calculated,
Proceeding to step 5T17, delay counter Cirb
is maintained at zero, and the process moves to step 5T18, where the above deviation dn
It is determined whether or not e is smaller than a predetermined value Kdne, and the process moves to step ST8, and the above-described operations are repeated until e becomes smaller than the predetermined value Kdne.

In other words, when the speed is reduced from the running state to the idle state,
As shown by the solid line in Figure 4, the actual rotational speed ne gradually decreases and then fluctuates, such as a slight increase. fluctuations are absorbed and changes smoothly. Then, until the deviation dne between the actual rotational speed ne and the smoothed rotational speed ned becomes equal to or less than the predetermined value Kdne (see point F in Figures 4 and 5).
, feedback control is not started.

After that, the idle speed, which is the actual speed ne, becomes stable,
Deviation dne between the above actual rotation speed ne and the smoothed rotation speed ned
When it becomes smaller than the predetermined value Kdne, the above step 5T
The determination in step 18 is YES, and the process moves to step 5T19.
It is determined whether the actual rotational speed ne is smaller than the target rotational speed no. If the actual rotational speed ne is smaller than the target rotational speed no, the process moves to step 5T20, where a predetermined value Kqfb is added to the previous feedback correction amount Q f b to set a new feedback correction = Qrb, If the actual rotation speed n8 is larger than the target rotation speed no,
The process moves from step 5T19 to step 5T21, where a predetermined value Kqfb is subtracted from the previous feedback correction amount Qfb to set a new feedback correction ff1Qrb.

Subsequently, in steps 5T20 and 5T21, when a new feedback correction ffi Q rb is set, the process moves to step ST8, and the ISCSC is set as described above.
The total air ff1Qt is calculated by adding the feedback correction mQtb to the pace Qb, and the ISC valve 16 is duty-controlled based on the total intake air RQt, and the idle rotation speed is feedback-controlled.

In other words, as shown at point F in Fig. 6, when the deviation dne between the actual rotational speed ne and the smoothed rotational speed ned becomes smaller, a feedback correction ffi Q f b occurs, and as shown in Fig. 4, the idle rotational speed ne is converged to the target rotation speed no.

Then, the above steps STI to ST5, ST8 to 5T2
1 constitutes the feedback control means 61, step 5T1B constitutes the smoothed rotation speed calculation means 62, step 5T16 constitutes the deviation detection means 63, step 5T
18 constitute a feedback starting means 64, respectively.

Therefore, calculate the annealed rotation speed ned by annealing the actual rotation speed ne of the engine 1, and calculate the annealed rotation speed ned between the actual rotation speed ne and the annealed rotation speed n.
Since the feedback control means 61 starts feedback control when the deviation dne from ed becomes equal to or less than the predetermined value Kdne, the idle rotation speed ne is feedback-controlled after the idle rotation speed ne becomes stable. Hunting can be prevented without significantly undershooting the idle rotation speed ne or the target rotation speed no. As a result, stability during idling can be significantly improved.

Furthermore, even when the idle speed ne is high, once the idle speed ne is stabilized, feedback control can be performed reliably, so the idle speed ne can be reliably controlled to the target speed no. , it is possible to prevent idle return failure at the time of erroneous learning.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention. 2 to 6 show an embodiment of the present invention, FIG. 2 is a general schematic diagram of the engine system, and FIG. 3 is a control flow diagram of the idle speed. FIG. 4 is a characteristic diagram showing the actual rotation speed and the smoothed rotation speed, FIG. 5 is a characteristic diagram showing the deviation between the actual rotation speed and the smoothed rotation speed, and FIG. 6 is a characteristic diagram of the feedback correction amount. 7 and 8 show the characteristics of the conventional example, where FIG. 7 is a characteristic diagram of the idle rotation speed, and FIG. 8 is a characteristic diagram of the feedback correction amount. 1... Engine 16... ISC valve 36... Rotation speed sensor (rotation speed detection means) 61...
Feedback control means 62...Annealed rotation speed calculation means 63...Deviation detection means and one other person ne Fig. 4 Fig. 5 Fig. 6 Fig. 6

Claims (1)

[Claims] (1) An engine equipped with a rotation speed detection means for detecting the rotation speed of the engine, and a feedback control means that receives a rotation speed signal from the rotation speed detection means and performs feedback control so that the idle rotation speed becomes the target rotation speed. In the idle rotation speed control device, an annealed rotation speed calculation means receives a rotation speed signal from the rotation speed detection means and calculates an annealed rotation speed by annealing the actual rotation speed; and a rotation speed of the rotation speed detection means. a deviation detection means that receives the signal and the calculation signal of the annealed rotation speed calculation means and detects the deviation between the actual rotation speed and the annealed rotation speed; and feedback starting means for starting feedback control of the feedback control means.