JP3352521B2 - Engine idle speed control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an idle speed control device for controlling an idle speed at the time of idling of an engine to a target speed by an ignition timing and an intake air amount.

[0002]

2. Description of the Related Art Conventionally, as an idling speed control device of this kind of engine, the amount of intake air at the time of starting the engine is increased so that the speed of the rotation at the time of starting is satisfactorily increased.
It is known that when an engine completely explodes, the amount of air is gradually reduced to reduce the engine speed to a target speed. However, in this case, there is a problem that the engine speed is excessively increased due to the variation in the intake air amount depending on the engine.

Therefore, in the prior art disclosed in Japanese Patent Laid-Open Publication No. Hei 1-318738, feedback control of the intake air amount is performed so that the engine speed reaches the target speed while the intake air amount is gradually decreasing immediately after the start of the engine. By doing so, the engine speed is increased.

[0004]

However, in this conventional apparatus, on the other hand, the amount of intake air is feedback-controlled after the engine is started. Therefore, this control causes the engine speed to settle to the target speed immediately after the start. In addition, it is undeniable that a good start feeling of the engine is impaired by a proper rise of the engine speed.

That is, when performing feedback control so that the engine speed becomes the target speed, usually,
When an external load such as an air conditioner driven by the engine is switched from the on state to the off state, the intake air amount is reduced accordingly, but the correction of the intake air amount is delayed. The rotation speed rises. For this reason, a guard is set in the control range for the feedback control of the ignition timing of the engine, etc., and when the external load is switched from the on state to the off state, this guard causes a delay in the correction of the reduction of the intake air amount. Nevertheless, an increase in the output torque of the engine is suppressed to prevent the engine speed from rising. Then, the guard of the output torque acts even immediately after the start of the engine, thereby suppressing the engine from blowing up.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to restrict a guard of a control amount when feedback-controlling the engine output torque so that the engine immediately after the engine is started. An object of the present invention is to make the rotation blow up well.

[0007]

In order to achieve the above object, according to the present invention, a predetermined period immediately after starting the engine is:
Compared to after the elapse of the predetermined period, the torque of the control amount when the engine speed is feedback-controlled to the target speed is lower
Lower guard value to reduce output torque
I made it.

More specifically, as shown in FIG. 1, the invention according to claim 1 includes a control means 33 for performing feedback control of a control amount such that the idle speed becomes the target speed when the engine 1 is idling. It is assumed that the engine idle speed control device is used.

A detecting means 34 for detecting that the engine 1 has been started, and a detecting means 34 for detecting that the starting state of the engine 1 has been detected by the detecting means 34 within a predetermined period.
Compared to the time after the elapse of the period, the control amount of the
The guard value on the engine output torque lower side is
And a control amount regulating means for setting so as to suppress a decrease in torque .

According to the second aspect of the present invention, the control means 33
When the engine 1 is idling, the ignition timing is corrected in accordance with the deviation between the target rotation speed and the actual rotation speed based on the ignition timing corrected by a predetermined delay from the basic ignition timing, and the idle rotation speed is set to the target. Feedback control is performed on the rotation speed. Further, the control amount regulating means 35 is provided at the time of idling.
The range of change in the ignition timing to the retard side is determined from the detection of engine start.
Set to be smaller during the fixed period than after the specified period
Shall be.

[0011] In the third aspect of the present invention, the control means 33, d
When the engine 1 is idling, the target speed and the actual speed
Correct the intake air amount according to the deviation and check the idle speed.
Shall feedback control target rotational speed, the control amount restricting means 35, the start of the engine 1 by the detection means 34
For a predetermined period after the detection, the
Limit the feedback control and adjust the intake air
It is assumed that the feedback control is started .

[0012]

With the above arrangement, in the first aspect of the present invention, when the engine 1 is idling, the control amount is feedback-controlled by the operation of the control means 33 so that the idle speed becomes the target speed. When this is detected by the detecting means 34 when the engine 1 is started, the detecting means 3
The control amount restricting means 35 receiving the signal from the control unit 4 controls the control means 3 until the predetermined period elapses from the start time.
Guard value on the engine output torque reduction side of the control amount by 3
Is set to suppress the decrease in engine output torque.
You . Therefore, immediately after the start, the control amount does not change to the side where the output torque decreases, and the output torque of the engine 1 can be increased and maintained. Can be.

After that, when the predetermined time period has elapsed, the control value is set to be suppressed on the engine output torque decreasing side of the control amount in the feedback control by the control amount restricting means 35.
Is released . Therefore, when the external load of the air conditioner or the like is switched from the on state to the off state, the control amount can be controlled within the large guard to prevent the engine speed from rising.

According to the invention of claim 2, when the start of the engine 1 is detected by the detecting means 34, the control amount regulating means 3
According to 5, from the start time until the predetermined period elapses,
Compared to after a predetermined period, the ignition timing at idle is retarded
Are set so that the width of change of is small. For this reason, immediately after the start, the ignition timing does not largely change to the retard side, which is the output torque decrease side, and the output torque immediately after the start of the engine 1 is maintained to be increased, so that the rotational speed can be kept good.

When the predetermined period elapses , the range of change of the ignition timing to the retard side is increased. Therefore, when the external load is switched from the ON state to the OFF state, the ignition timing is set within the guard. By controlling, the engine speed can be prevented from rising.

According to the third aspect of the invention, when the detection state of the engine 1 is detected by the detection means 34, the control amount restricting means 35 is provided for a predetermined period from the start time.
Restricts feedback control based on intake air volume
It is. For this reason, if there is an increase in the amount of intake air at the start,
That is due to the regulation of the intake air feedback control.
The output torque is maintained as it is, and the output torque immediately after the start of the engine 1 is increased and maintained, so that the rotational speed can be kept good.

When a predetermined period has elapsed from the start of the engine 1, feedback control based on the intake air amount is started.
This prevents the engine speed from rising when the external load is switched from the on state to the off state .

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 16 shows an engine control device according to the embodiment of the present invention. An engine 1 includes a cylinder block 3 having a plurality of cylinders 2, 2,... (Only one is shown), a cylinder head 4 mounted on an upper surface of the cylinder block 3, and each cylinder 2. And a piston 5 reciprocally fitted therein. A combustion chamber 6 surrounded by the piston 5 and the cylinder head 4 is formed in each cylinder 2. Reference numeral 7 denotes an ignition plug provided above the combustion chamber 6 in the cylinder 2. The ignition plug 7 is connected to an ignition coil 8 which receives an ignition signal from a control unit 25 described later and generates a high-voltage secondary voltage. Connected through.

Reference numeral 11 denotes an intake passage for supplying intake air (air) to the combustion chamber 6 in each of the cylinders 2. The upstream end of the intake passage 11 is connected to an air cleaner (not shown). On the other hand, the downstream end of the intake passage 11 is constituted by an intake port 11b in the cylinder head 4, and this intake port 11b is
It communicates with the combustion chamber 6 via 1a. Intake passage 11
A hot-wire airflow sensor 12 for detecting the amount of intake air actually sucked into the engine 1, a throttle valve 13 for restricting the intake passage 11, a surge tank 14,
A fuel injection valve 15 (injector) for supplying fuel by receiving a fuel injection signal from the control unit 25 is arranged in order from the upstream side.

The intake passages 11 on the upstream and downstream sides of the throttle valve 13 are connected by a bypass passage 17, and the bypass passage 17 is driven by an actuator 18 which operates upon receiving an ISC valve drive signal from a control unit 25. An ISC valve 19 (idle speed control valve) is provided.
By controlling the opening of the C valve 19, the idle speed of the engine 1 is controlled.

On the other hand, reference numeral 21 denotes an exhaust passage for exhausting the exhaust gas in the combustion chamber 6, the upstream end of which is connected to the combustion chamber 6 via an exhaust valve 21a. In the middle of the exhaust passage 21, an air-fuel ratio sensor 22 for detecting an air-fuel ratio of intake air based on the oxygen concentration in the exhaust gas, and an exhaust purification device 23 for purifying the exhaust gas are arranged in this order from the upstream side. . The air-fuel ratio sensor 22 is constituted by a linear O2 sensor whose output signal changes in proportion to the change in the air-fuel ratio.

The actuators 18 of the fuel injection valve 15, the ignition coil 8 and the ISC valve 19 are controlled by a control unit 25 (specifically, an engine control unit). The control unit 25 includes an intake air amount signal output from the air flow sensor 12 and the distributor 9 corresponding to the rotation angle of the crankshaft (not shown) of the engine 1 for calculating the engine speed ne. , The output signal of the air-fuel ratio sensor 22, and the coolant temperature t of the engine 1, which is provided on the water jacket 3 a of the cylinder block 3 of the engine 1.
hw, a water temperature signal from a water temperature sensor 26, an on / off signal of an idle switch 27 for detecting that the throttle valve 13 is fully closed, and an air conditioner switch for detecting an operation state of an air conditioner (not shown). 28, and an on / off signal of a power steering switch 29 for detecting an operating state of a power steering device (not shown) as a device having a hydraulic pump (not shown) that is drivingly connected to the engine 1 and that changes load. / OFF signal, a signal from a neutral switch 30 for detecting that a transmission (not shown) is in a neutral state, and various other electric load signals such as an alternator (not shown). I have.

The power steering switch 29 is
The power steering device includes an oil pressure switch that detects on-off when the hydraulic pressure of the power steering device driven by the engine 1 rises and the load caused by the increase becomes a predetermined value or more as the operation state of the power steering device.

In the control unit 25,
When the engine 1 is idling, the ignition timing based on the ignition signal to the ignition coil 8 (spark plug 7) and the ISC valve 19
The signal processing operation for controlling the intake air amount by the air amount signal to the actuator 18 will be described with reference to FIGS. That is, FIG. 2 shows a main routine of the ignition timing control. In step S1, the engine speed ne is calculated. In the next step S2, the intake air amount detected by the air flow sensor 12 is divided by the engine speed ne. After that, a constant is multiplied to calculate the air filling efficiency Ce.
The basic advance amount thtbse corresponding to the air filling efficiency Ce is calculated from the map shown in FIG. This basic advance amount tht
bse is an ignition timing at which the output torque of the engine 1 becomes maximum, and is set according to the engine speed ne.

After step S3, steps S4 to S
Proceeding to 8, the start determination of the engine 1 is performed. First, in step S4, the engine speed ne is set to the target idle speed no.
It is determined whether it is greater than or equal to. This determination is ne ≦ no
If NO, the process proceeds to step S5 to determine whether the engine speed ne is lower than a set value A (for example, 300 rpm). If this determination is negative for ne <A, the process proceeds to step S9, but if yes for ne ≧ A, the feedback execution determination flag xn is determined in step S6.
After setting kst to xnkst = 0 and setting the count value cstd of the counter to cstd = B (for example, about 3 seconds) in step S7, the process proceeds to step S9. When ne> no is determined in step S4, the feedback execution determination flag xnkst is set to xnkst in step S8.
After setting to = 1, the process proceeds to step S9.

Steps S9 to S13 are steps for determining the execution of the feedback control of the ignition timing. In step S9, the feedback execution determination flag xnkst is determined.
Is determined to be xnkst = 1. This judgment is YE
In the case of S, the counter value cstd is determined in step S10.
Is decremented, and in step S11, an idle determination flag xidld indicating the ON state of the idle switch 27 is set.
Is determined whether or not xidld = 1. This judgment is xid
When ld = 1 is YES, the idle execution condition determination flag xafb is set to xafb = 1 in step S12, and then the process proceeds to step S14. On the other hand, step S
When the determination of No. 9 is NO for xnkst = 0, and when the determination of step S11 is NO for xidld = 0, the idle execution condition determination flag xafb is reset to xafb = 0 in step S13, and then in steps S14 and S14. Proceed to S15. As described later, the above step S1
In step 4, the idle retard amount thtret is calculated, and in step S15, the feedback advance amount thtfb is calculated. Thereafter, in step S16, the final ignition timing is calculated by subtracting the idle retard amount thtret from the basic advance amount thtbse and adding the feedback advance amount thtfb.

The details of the routine for calculating the idle retard amount thtret performed in step S14 are as shown in FIG. 3. First, in step T1, it is determined whether or not the idle execution condition determination flag xafb is equal to xafb = 1. If this determination is YES of xafb = 1, the idle maximum retard amount thtretmax is calculated in step T2. The maximum retard amount thtretmax indicates how much the ignition timing is retarded when the feedback execution condition is satisfied. As shown in FIG. 6, the air filling efficiency Ce and the presence or absence of the operation of the power steering device It is set according to. In FIG. 6, xpst = 1 indicates the operating state of the power steering system, xpst = 0 indicates the non-operating state of the system, and the former operating state corresponds to the maximum load of the power steering system. The ignition timing retard amount thtret is such that the engine output torque obtained is obtained.

Thereafter, the idle maximum retard amount thtr
In step T3, a predetermined value C is added to the previous idle retard amount thtret [i-1] to gradually change the torque of the engine 1 by gradually switching to etmax, and to perform a new idle retard. The amount thtret is obtained, and in step T4, the calculated idle retard amount th
It is determined whether or not the tret is equal to the maximum retard amount thtretmax. This determination is thtret ≦ thretmax
If NO, thtret> tht
When the answer to retmax is YES, in step T5, the idle retard amount thtret is reduced to the maximum retard amount thtretma.
After replacing with x, the process ends.

On the other hand, the determination in step T1 is xafb
When NO = 0, similarly to the above, in order to gradually switch to the idle maximum retard amount thtret,
In step T6, the previous idle retard amount thtr
A new idle retard amount thtret is obtained by subtracting a predetermined value D from et [i-1], and it is determined in step T7 whether the idle retard amount thtret is smaller than zero. If this determination is NO when thtret ≧ 0, and if YES when thtret <0, the idle retard amount thtret is set to thtret in step T8.
After setting = 0, the process ends.

The details of the routine for calculating the feedback advance amount thtfb performed in step S15 are as shown in FIG. 4. First, in step U1, it is determined whether the idle execution condition determination flag xafb = 1 or not. When this determination is NO of xafb = 0, the feedback advance amount thtfb is set to th at step U2.
The process ends after setting tfb = 0, but the determination is xafb = 1.
If the answer is YES, the routine proceeds to step U3, where it is determined whether or not the engine speed ne is higher than the target idle speed no. When this determination is NO of ne ≦ no,
In step U4, the feedback advance amount thtfb is multiplied by a value obtained by dividing the calculated idle retard amount thtret by a difference between the target idle speed no and the actual speed ne of the engine 1 by a predetermined value E. In step U5, the feedback advance amount tht is calculated.
The magnitude of fb and the idle retard amount thtret are determined. If this determination is NO at thtfb <thtret, or YES at thtfb ≧ thtret
In step U6, the feedback advance amount th
tfb as the maximum value of the idle retard amount thtre
After setting to t, the process ends.

If the determination in step U3 is that Y satisfies ne ≦ no
In the case of ES, it is determined in step U7 whether or not the count value cstd of the counter is larger than 0. As shown in FIG. 7, this determination is NO when cstd ≦ 0.
In step U8, the idle retard amount tht
ret is multiplied by a predetermined value F to obtain a feedback advance amount tht.
Minimum value of fb thtfbmin (= thtret × F)
If the determination is cstd> 0, the idle retard amount thtret is set to the predetermined value F in step U9.
Is multiplied by another predetermined value G (<F) smaller than the minimum value thtfbmin (= ttfbmin) of the feedback advance amount thtfb.
htret × G), and in the subsequent step U10, the deviation between the target idle speed no and the actual speed ne with respect to the negative value of the calculated idle retard amount thtret as in step U4. Is multiplied by a predetermined value E to obtain the feedback advance amount thtfb.
Is calculated. Next, in step U11, the feedback advance amount thtfb and the feedback advance amount t
htfb is determined to be greater or smaller than a minimum value thtfbmin,
When this determination is NO in thtfb <thtfbmin, Y in thtfb ≧ thtfbmin
In the case of ES, the feedback advance amount thtfb is set to its minimum value thtfbmin in step U12, and the process is ended.

On the other hand, FIG. 8 shows a main routine of the ISC control for controlling the intake air amount by the ISC valve. In the first step V1, the cooling water temperature th of the engine 1 is set.
w is inputted, and in step V2, a basic air charging efficiency Cebase corresponding to the cooling water temperature thw is calculated from a map previously set as shown in FIG. Thereafter, in step V3, the state of the flag xcol indicating the on / off state of the air conditioner switch 28 is determined. When this determination is xcol = 1, it is determined that the air conditioner is operating due to the on state of the air conditioner switch 28. In step V4, the air conditioner load correction amount Ceac is set to a predetermined value A,
When the determination is xcol = 0, it is determined that the air conditioner is in the inactive state due to the OFF state of the air conditioner switch 28, and the air conditioner load correction amount Ceac is set to Ceac = 0 in step V5, and then the process proceeds to step V6.

In step V6, a flag xpst indicating the on / off state of the power steering switch 29 is set.
Is determined, and when this determination is xpst = 1,
Assuming that the power steering device is operating due to the ON state of the power steering switch 29, step V
7, the power steering load correction amount Ceps is set to a predetermined value B.
When the determination is xpst = 0, it is determined that the power steering device is in the inactive state due to the OFF state of the power steering switch 29, and the power steering load correction amount Ceps is set to Ceps = 0 in step V8. Go to V9.

In step V9, the state of the flag xel indicating the on / off state of the other electric loads is determined. When this determination is xel = 1, it is determined that the electric load is operating and in step V10 the electric load is determined. When the correction amount Cell is set to the predetermined value C, and the determination is xel = 0, the electric load is determined to be in the non-operation state, and the electric load correction amount Cell is set to Cell = 0 in step V11.
Proceed to step V12.

In steps V12 to V14, the start of the engine 1 is determined. First, at step V12, it is determined whether or not the engine speed ne is larger than the target idle speed no. If this determination is NO, that is, if no≤no, then at step V14, the engine speed ne is increased from the set value A (300 rpm). Is also low.
When this determination is NO ≧ ne ≧ D, the process proceeds to step V16, but when ne <A is YES, the process proceeds to step V15
After the start determination flag Xnst is set to Xnst = 0, the process proceeds to step V16. If the determination in step V12 is YES, that is, ne> no, the start determination flag Xnst is set to Xnst = 1 in step V13, and then the process proceeds to step V16.

In step V16, the state of the start determination flag Xnst is determined.
When it is determined that the engine 1 has not been started yet, the post-start increase correction amount Cesw is set to the predetermined value E, and when the determination is Xnst = 1, it is determined that the engine 1 has been started. Post-start increase correction amount Cesw
Are decremented, and then steps V19 and V2 are respectively performed.
Go to 0.

As will be described later, in step V19, IS
The feedback execution determination flag xifb of the C control is updated, and in step V20, the feedback correction amount Ce is updated.
Compute fb. In step V21 after step V20, the basic charging efficiency Cebase, the air conditioner load correction amount Ceac, and the power steering load correction amount C
eps, electric load correction amount Cele, post-start increase correction amount C
esw and the feedback correction amount Cefb are all added to calculate the required charging efficiency Cetno, and the next step V2
2, the required mass flow rate gtota is obtained by multiplying the required charging efficiency Cetno by the target idle speed no and the predetermined value F.
Calculate l. Thereafter, in step V23, the required mass flow rate gtotal is divided by the intake air density to calculate the required volume flow rate qtotal. In the final step V24, the required volume flow rate qtotal is calculated in advance according to the cooling water temperature thw as shown in FIG. Set bypass flow rate q
After calculating the ISC flow rate by subtracting main, the process ends.

The details of the ISC feedback execution determination flag update routine performed in step V19 are as shown in FIG. 9. First, in step W1, the start determination flag x
Determine the state of nst. When this determination is xnst = 1, it is determined that the engine 1 has been started, the process proceeds to step W2, and the idle determination flag xidld (FIG. 2)
(See Reference). If this determination is YES of xidld = 1, it is considered that the engine 1 is in the idle state, and the process proceeds to step W3. This time, the neutral determination flag xgri is determined by the signal from the neutral switch 30.
The state of n is determined, and if this determination is xgrin = 0, it is determined that the transmission is in the neutral state, and the routine proceeds to step W4. In this step W4, the engine speed n
e is determined to be greater than or equal to the target idle speed no, and if this determination is YES with ne ≦ no, the feedback execution determination flag xifb is set to xifb in step W6.
After setting = 1, the process ends.

On the other hand, if the determination in step W4 is NO>ne> no, the process proceeds to step W5, where it is determined whether or not the starting increase correction amount Cesw is Cesw = 0.
If this determination is NO for Cesw ≠ 0, the process is terminated and the feedback execution determination flag xifb is set to xi.
fb = 1, but Cesw = 0 and the determination is YE
When S is reached, the feedback execution determination flag xifb is set to xifb = 1 in step W6.

If xnst = 0 is determined in step W1, xidld = 0 is determined in step W2, or xgrin = 1 is determined in step W3, the process proceeds to step W7. The process ends after the feedback execution determination flag xifb is set to xifb = 0.

The details of the feedback correction amount calculation routine performed in step V20 are as shown in FIG. 10. In step X1, the state of the ISC feedback execution determination flag xifb is determined. This judgment is xifb
When = 0, the feedback correction amount Cefb is set to Cefb = 0 in step X2, and then the process ends.

Also, if the determination in step X1 is xifb = 1
In step X3, a value obtained by multiplying the deviation between the target idle speed no and the actual speed ne of the engine 1 by a predetermined value G is added to the previous feedback correction amount Cefb [i-1], and a new value is added. In step X4, the magnitude of the feedback correction amount Cefb and the maximum value H are determined. If this determination is YES of Cefb> H, the feedback correction amount Cefb is set to the maximum value H in step X5, and then the process ends. Also, the determination in step X4 is C
When efb ≦ H is NO, the process proceeds to step X6, and the magnitude of the feedback correction amount Cefb and the minimum value J is determined this time. When this determination is NO for Cefb ≧ J, and when Cefb <J is YES, the feedback correction amount Cefb is set to the minimum value J in step X7.
After that, the process ends.

In this embodiment, W1 to W
7 and steps V19 to V2 including steps X3 to X7
4 constitutes a first control means 31 for performing feedback control of the intake air amount as a control amount when the engine 1 is idling. Steps S9 to S16 including steps U1 to U12 constitute a second control means 32 for performing feedback control of the ignition timing as a control amount, and the first and second control means 31, 32 control the control means 33.
Is configured. Then, the second control means 32
Feedback control advancement amount as a control amount in accordance with the deviation between the target rotation speed no and the actual rotation speed ne based on the ignition timing of the idle retardation amount thtret which is retarded by a predetermined value from the basic advancement amount thtbse. thtfb is corrected, and the idle speed ne is feedback-controlled to the target speed no.

Steps S4 to S8, V12 to V1
5, the engine speed ne becomes equal to the set value A (300 rpm).
The detecting means 34 is configured to detect a time lower than m) as the starting state of the engine 1.

Further, steps U7 to U9, V16 to V
18, W5, W6, X1, X2, control amount regulating means 3
The control amount restricting means 35 is provided when the detecting means 34 detects the start state of the engine 1.
The post-start increase correction amount Cesw is set to a predetermined value E to increase the intake air amount, and the post-start increase correction amount Ce
For a predetermined period until sw becomes Cesw = 0, the feedback execution determination flag xifb is kept at xifb = 0, and the feedback correction amount Cef by the first control means 31 is set.
b is set to Cefb = 0 to limit the feedback control of the intake air amount, and the feedback of the ignition timing by the second control means 32 for a predetermined period (3 seconds) when the count value cstd of the counter becomes 0 from the start time. The retard lower limit value thtfbmin of the guard in the control is set to thtfbmi.
It is configured such that n = thtret × G, which is smaller than the same lower limit value thtfbmin (= thtret × F) of other idle states.

Therefore, in the above-described embodiment, when the rotation speed ne of the engine 1 is lower than the predetermined value A (300 rpm), it is determined that the engine 1 has been started. At this start, the count value cstd of the counter is set to the predetermined value B (3 seconds). ). Immediately after the start of the engine 1, the post-start increase correction amount Cesw is set to the predetermined value E, the intake air amount is increased, and the start increase correction amount Ces is set.
Until w becomes Cesw = 0, the feedback execution determination flag xifb is kept at xifb = 0 (see steps W5 and W6 in FIG. 9), and the feedback correction amount Cefb of the intake air amount is set to Cefb = 0. Feedback control on the intake air amount is prohibited. Also,
Only feedback control of the ignition timing is performed so that the idle speed ne becomes the target speed no. Thereafter, when a predetermined time elapses until the count value cstd of the counter reaches cstd = 0, feedback control of the intake air amount is performed in addition to the control of the ignition timing.

Regarding the control of the ignition timing, basically, the basic advance amount th at which the maximum torque of the engine 1 is obtained.
idle delay amount th corrected by a predetermined value with respect to bse
tret is calculated, and the idle retard amount thtret is calculated.
Is the maximum value tht calculated according to the air filling efficiency Ce
It is gradually changed until retmax. The feedback advance amount thtfb is set based on the deviation between the target rotation speed no and the actual rotation speed ne of the engine 1 based on the ignition timing of the idle retard amount thtret, and the maximum value thereof is set as the idle retard amount thtret. And the minimum value is thtf
bmin is calculated while guarded between the two,
The ignition timing is feedback-controlled by adjusting the feedback advance amount thtfb so that the idle speed ne becomes the target speed no.

Then, the count value cst of the above counter is obtained.
As shown in FIG. 15, the predetermined time until d becomes cstd = 0 is that the minimum value thtfbmin of the feedback advance amount thtfb is thtfbmin = thtret.
× G, which is smaller than the normal value thtret × F, and when the predetermined time elapses, the normal value thtre
It is changed to t × F (see steps U7 to U9 in FIG. 4).

As described above, for a predetermined time after the start of the engine 1, the lower limit value thtfbmin of the feedback advance amount thtfb of the ignition timing is reduced, so that the ignition timing greatly changes to the retard side immediately after the start. Can be regulated. In addition, during this time, the startup increase correction of the intake air amount is performed as described above, and the increase correction amount C of the intake air amount is obtained.
Until esw becomes Cesw = 0, the feedback control of the intake air amount is restricted, so that the startup increase correction of the intake air amount is maintained as it is. As a result, the output torque immediately after the start of the engine 1 is increased and maintained, and the engine speed ne can be smoothly increased. can do.

Further, as described above, after a predetermined time has elapsed from the start of the engine 1, the lower limit value thtfbmin of the feedback advance amount thtfb is changed to a large value (= thtret × F) as usual, so that the air is released during idling. Even if the external load such as the harmony device is switched from the on state to the off state, and there is a delay in reducing the amount of air accompanying this, the ignition timing can be corrected by the regulation by the large upper and lower limit guards, and the engine rotation can be reduced. Blowing can be prevented.

Further, in this embodiment, the idling maximum retard amount tht serving as a reference value of the ignition timing of the idling operation is set.
As shown in FIG. 6, retmax has two kinds of characteristics that change depending on whether or not the power steering device is operated. When the power steering device is operated, the idle maximum retard amount thretmax is set to be larger than when the power steering device is not operated. Therefore, the flag xps indicating the on / off state of the power steering switch 29 according to the on state of the power steering switch 29
When t (see step V6 in FIG. 8) becomes xpst = 1 and the operation of the power steering device is detected, the idle maximum retard amount thtretmax is switched from the characteristic of xpst = 0 to the characteristic of xpst = 1. As shown in FIG. 13, the width of the advance angle thtfb from the idle maximum retard amount thtretmax (the reference ignition timing) is increased by the increase in the idle maximum retard amount thtretmax as shown in FIG. For this reason, even when the operation of the power steering device is detected based on the signal of the hydraulic power steering switch 29 that detects that the oil pressure of the power steering device has risen to a predetermined value or more, the operation state of the power steering device is not changed. When the steering wheel (not shown) is further turned and the load of the power steering device increases and changes, the advance amount thtfb from the idle maximum retard amount thtretmax correspondingly increases and the output torque of the engine 1 decreases. Can increase. Therefore, as shown in FIG. 14, the load during operation of the power steering apparatus is small, and the intake air amount IS
Even if the load increases and the output torque of the engine 1 tries to decrease due to the shortage of the intake air amount from the state where the intake air amount decreases due to the C control (see steps V19 to V24 in FIG. 8), it is set to the ignition timing. Can be quickly compensated for by the advance angle of the power steering device, and therefore, it is possible to reliably and promptly prevent the idle rotation of the engine 1 from decreasing due to the load fluctuation of the power steering device.

In such a case, if such an increase correction of the maximum idle retard amount thtretmax is constantly performed, the rotation of the engine 1 will drop due to the correction of the ignition timing on the retard side, and the intake air amount will increase by the ISC control accordingly. As a result, fuel efficiency may be reduced. However, in this embodiment, the increase correction of the idle maximum retard amount thtretmax is performed only when the operation of the power steering device is detected by the operation of the power steering switch 29. Is small, and the fuel efficiency of the engine 1 does not greatly deteriorate as a whole.

The maximum idle retard amount thtretma when the power steering device is in the operating state.
x is the ignition timing retard amount thtret such that an engine output torque corresponding to the maximum load of the power steering device can be obtained. Therefore, as described above, the hydraulic pressure in the power steering device increases to a predetermined value or more. Even if the load on the power steering device further increases after the power steering switch 29 detects that the load has become equal to or greater than the predetermined value, the idle maximum retard amount thtr of the ignition timing is maintained until the load reaches the maximum load.
correction of the advance amount thtfb from et can be performed,
A sufficient lead angle correction amount can be secured.

In the above-described embodiment, when the engine 1 is idling, the idle retard amount thtret is set with respect to the basic advance amount thtbse of the ignition timing, and the feedback advance amount thtf with respect to the idle retard amount thtret.
The minimum value thtfbmin of b is set to a normal value (= thtret ×
F), the lower limit guard value of the feedback control range of the intake air amount may be reduced for a predetermined period from the start. The effect is obtained.

[0055]

As described above, according to the first aspect of the present invention, when the control amount is feedback-controlled so that the idling speed becomes the target speed at the time of idling of the engine, a predetermined value is set from the start of the engine. Until the period elapses, the control amount is more energized than after the predetermined period elapses.
The guard value on the lower side of the gin output torque is used as the engine output torque.
The control amount can be prevented from changing to the side where the output torque decreases immediately after the engine is started. However, it is possible to prevent the idle speed from rising when the external load of the air conditioner or the like is switched from the on state to the off state.

According to the second aspect of the present invention, the control amount for feedback-controlling the idle speed of the engine is used as the ignition timing. When the engine is idling, the ignition timing that is delayed by a predetermined value from the basic ignition timing is corrected. the ignition timing is corrected in accordance with the deviation between the actual speed and the target rotational speed as a reference, so as to feedback control the idle speed to the target speed, within a predetermined time period from the start detection of the engine
Compared to after a predetermined period, the ignition timing at idle is retarded
Is set to be small so that the ignition timing is corrected based on the ignition timing corrected by a predetermined delay from the basic ignition timing until the predetermined period elapses from the start of the engine. Therefore, when the idle speed is feedback-controlled to the target speed, the ignition timing shifts to the retard side.
The ignition timing is controlled inside the guard when the external load is switched from on to off, while maintaining the output torque immediately after the start of the engine and maintaining good rotational speed. As a result, it is possible to prevent the engine speed from rising.

According to the third aspect of the present invention, the engine eye
In dollars, suction is performed according to the deviation between the target speed and the actual speed.
The intake air amount is corrected, the idle speed is controlled to the target speed, and when the starting state of the engine is detected,
The amount of intake air from when the engine starts until the specified period elapses
Limiting the feedback control by, after a predetermined period of time
By starting the feedback control based on the intake air amount , the intake air amount is
In this way, it is possible to maintain the increase in the intake air amount at the time of starting, maintain the increase in the output torque, and keep the rotational speed good, and at the time of idling, the external load is turned on. It is possible to prevent the engine speed from rising when switching from the OFF state to the OFF state .

[Brief description of the drawings]

FIG. 1 is a configuration diagram of the present invention.

FIG. 2 is a flowchart illustrating a signal processing operation of a main routine of ignition timing control during idling of an engine performed in the control unit according to the embodiment of the present invention.

FIG. 3 is a flowchart illustrating a signal processing operation of an idle retard amount calculation routine.

FIG. 4 is a flowchart illustrating a signal processing operation of a feedback advance angle calculation routine;

FIG. 5 is a characteristic diagram showing a map of a basic advance amount of ignition timing with respect to an intake charge amount.

FIG. 6 is a characteristic diagram showing a map of a maximum retard amount of an ignition timing with respect to an intake charge amount.

FIG. 7 is a characteristic diagram showing guarding of a feedback advance amount of an ignition timing with respect to an intake charge amount.

FIG. 8 is a flowchart showing a signal processing operation of a main routine of ISC control at the time of idling performed by the control unit.

FIG. 9 is a flowchart illustrating a signal processing operation of an ISC execution condition determination routine.

FIG. 10 is a flowchart illustrating a signal processing operation of a feedback correction amount calculation routine.

FIG. 11 is a characteristic diagram showing a map of an intake basic charging efficiency with respect to an engine cooling water temperature.

FIG. 12 is a characteristic diagram showing a map of a bypass flow rate with respect to an engine coolant temperature.

FIG. 13 is a characteristic diagram showing a change in engine output torque with respect to a retard amount of a reference ignition timing.

FIG. 14 is a characteristic diagram showing characteristics of an ISC load correction amount according to a change in oil pressure in the power steering device.

FIG. 15 is a time chart showing changes in the amount of feedback advance of the engine speed and the ignition timing after the start of the engine.

FIG. 16 is a diagram illustrating an overall configuration of an embodiment.

[Explanation of symbols]

DESCRIPTION OF REFERENCE NUMERALS 1 engine 2 cylinder 7 spark plug 11 intake passage 13 throttle valve 17 bypass passage 19 ISC valve 25 control unit 31 first control means 32 second control means 33 control means 34 detection means 35 control amount restriction means thtbse basic advance amount thtret idle Retard amount (reference value) thtfb feedback advance amount (control amount) thtfbmin feedback advance amount minimum value (guard lower limit value) cstd count value Cesw increase correction amount after start Cefb feedback correction amount

────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI F02D 45/00 312 F02D 45/00 312B F02P 5/15 F02P 5/15 EK (56) References JP-A 1-318738 ( JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 41/16 F02D 41/04 315 F02D 41/08 315 F02D 43/00 301 F02D 45/00 312 F02P 5/15

Claims (3)

(57) [Claims] 1. An engine idling speed control device having a control means for performing feedback control of a control amount such that an idling speed becomes a target speed when the engine is idling, wherein an engine start is detected. Detecting means, and whether the starting state of the engine is detected by the detecting means .
Within a predetermined period, the guard amount on the engine output torque reduction side of the control amount by the control means is smaller than after the predetermined period has elapsed.
The value is set so that the decrease in the engine output torque is suppressed.
And a control amount restricting means for controlling the idling speed of the engine. 2. The engine idle speed control device according to claim 1, wherein the control unit determines the target engine speed and the actual engine speed based on the ignition timing corrected by a predetermined value later than the basic ignition timing when the engine is idle. of the ignition timing is corrected in accordance with the deviation between the rotational speed, which the feedback control of the idle speed to the target speed, the control amount restricting means, the ignition timing during idling of the retard side
The change width is within the specified period from the detection of engine start for the specified period
An idle speed control device for an engine, which is set so as to be smaller than a later one . 3. The engine idle speed control device according to claim 2, wherein the control means controls the target engine speed and the actual engine speed when the engine is idle.
The intake air amount is corrected according to the deviation from the
Feedback control of the motor speed to the target speed.
The control amount regulating means detects the start of the engine by the detecting means.
For a predetermined period after the air is discharged, feed
Back control is restricted, and after a predetermined period
An idle speed control device for an engine, characterized in that the feedback control is started .