JPH02252943A - Idle revolution speed controller for engine - Google Patents

Abstract

PURPOSE:To improve the idling stability by detecting the feedback quantity of the ignition timing control for an engine and setting the feedback quantity in the ignition quantity control so that the feedback quantity of the ignition timing control reduces. CONSTITUTION:The ignition timing of an engine is adjusted by an ignitor A, and the intake quantity is adjusted by an idle control valve B. Ignition timing correction F and intake quantity correction G are carried out so that the engine revolution speed C becomes equal to an aimed value D on the basis of the difference E between the engine revolution speed C and the aimed value D of the idle revolution speed. In this case, the feedback quantity H of the ignition timing correction F on the basis of the difference E is detected. The feedback quantity of the intake quantity correction G is set so that the feedback quantity H of the ignition timing correction F reduces according to the detection I. In other words, the intake quantity correction G is subordinated to the ignition timing correction F, and the ignition timing is speedily returned to the normal ignition timing.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an engine idle speed control device,
In particular, it relates to a device in which the ignition timing and the intake air amount are feedback-controlled so that the target idle speed is achieved, and the intake air amount is controlled so that the feedback amount of the ignition timing is reduced.

[Prior art]

BACKGROUND ART Conventionally, among idle speed control devices that control the engine speed so as to reach a target idle speed, devices that precisely feedback control the intake air amount via an ISO valve have been widely put into practical use.

This feedback control based on intake air volume lacks responsiveness because it takes a long time after the intake air volume is changed until it is reflected in the engine speed, and it is not sufficient to cope with cases where the engine speed fluctuates rapidly and frequently. However, there are drawbacks such as the fact that there is no response, and that hunting is likely to occur due to the low response.

Therefore, recently, the intake air amount feedback control using the ISO valve is combined in parallel with ignition timing feedback control, which has excellent responsiveness, to feedback control the intake air amount and ignition timing based on the deviation between the actual rotation speed and the target idle rotation speed. An idle speed control device has been proposed.

For example, in Japanese Patent Application Laid-open No. 61-53544, the amount of air-fuel mixture to the engine is controlled so that the engine speed becomes the target idle speed, and the deviation between the engine speed and the target idle speed and the engine speed are further disclosed. A technique is described in which the ignition timing is controlled according to at least one of the amount of variation in the number.

In the engine speed control technology described in the above publication,
Based on the deviation between the actual rotation speed and the target rotation speed or the amount of variation in the engine rotation speed, intake air amount control and ignition timing control are individually executed in parallel.

In addition, in feedback control of the intake air amount using the ISO valve, ±ΔNR (ΔN
A dead zone with a width of II=20-30rpI11) is provided.

[Problem to be solved by the invention]

As mentioned above, in conventional idle speed control devices, feedback control of ignition timing, which has excellent responsiveness, and feedback control of intake air volume, which has low responsiveness, are performed independently and individually. When the engine speed N falls below the target idle speed N0 due to a load acting on it, such as when the engine is turned on, the deviation ΔN (ΔN=N0
-N), ignition timing feedback control and intake air amount feedback control are performed, but the ignition timing feedback control, which has excellent responsiveness, progresses rapidly and the engine speed increases due to the ignition timing being corrected to the advanced side. As a result, the deviation ΔN decreases, and substantially in parallel with this, feedback control of the intake air amount is performed. As a result, when ΔN=0, the ignition timing control and the intake air amount control maintain their respective states, so the ignition timing advance angle correction amount is fixed to that value.

To explain further with reference to FIG. 13, during idling, the ignition timing in the ignition timing/torque characteristics is approximately at the center of the linear region A of the characteristics. Although it is desirable to set the ignition timing so that the ignition timing can be freely corrected in the direction of increasing torque or decreasing torque according to load fluctuations, as mentioned above, the ignition timing is not advanced. If the ignition timing is corrected to 01 and fixed at that value θ, the allowable range in which the ignition timing can be corrected to the side where the rotational speed increases (to the side where the torque increases) becomes narrower, and ignition timing feedback control becomes effective when the load increases. The problem is that it cannot be done.

This means that the ignition timing control works when ΔNeo is ΔN
The same is true when the ignition timing is set to #0 and the ignition timing is fixed at a retarded θ.In this case, the torque value is low, resulting in a disadvantage in terms of fuel efficiency.

On the other hand, when a large load acts and a large deviation ΔN occurs, the ignition timing is advanced to the best torque advance angle θ□7 by ignition timing feedback control with excellent responsiveness, and from then on the ignition timing is set at that value θ□ It is fixed to the chin.

At this time, even if ΔN≠0, if the deviation ΔN enters the dead zone of the intake air amount feedback control, the intake air amount feedback control will also be held in that state, so ΔN≠0
In other words, there is a problem in that even though the engine speed is not the target idle speed, both the ignition timing feedback control and the intake air amount feedback control become fixed.

As explained above, various problems arise when the ignition timing feedback control and the intake air amount feedback control each have a deviation ΔN.
This is a problem that inevitably arises when operations are carried out independently based on the following.

An object of the present invention is to provide an engine idle speed control device that can improve idle stability and improve fuel efficiency during idle operation.

[Means to solve the problem]

An engine idle speed control device according to the present invention includes: an ignition timing adjustment means for adjusting ignition timing; an intake air amount adjustment means for adjusting an intake air amount; a rotation speed detection means for detecting the actual engine speed; Idle rotation of an engine equipped with ignition timing control means and intake air amount control means for feedback controlling the ignition timing adjustment means and intake air amount adjustment means, respectively, so that the actual rotation speed detected by the number detection means becomes the target idle rotation speed. In the numerical control device, the feedback amount detection means detects the feedback amount of the ignition timing control by the ignition timing control means, and the intake air amount is controlled so that the feedback amount of the ignition timing control is reduced in response to the output of the feedback amount detection means. The device includes feedback amount setting means for setting a feedback amount for intake air amount control in the means.

[Effect]

In the engine idle speed control device according to the present invention, a load acts when the engine is in an idle state,
When a deviation ΔN (ΔN=N, -N) between the target idle rotation speed N0 and the actual rotation speed N detected by the rotation speed detection means occurs, the ignition timing is adjusted by the ignition timing control means based on the deviation ΔN. Under feedback control, the engine speed N converges to the target idle speed N0 with high responsiveness. In parallel with this, the feedback amount detection means detects the feedback amount of the ignition timing feedback control, and the feedback amount setting means sets the feedback amount of the intake air amount control in the intake air amount control means so that the feedback amount decreases. and the intake air amount is feedback-controlled.

That is, initially in the state of ΔN#0, the ignition timing is set to an appropriate predetermined ignition timing (this will be referred to as the normal ignition timing) corresponding to approximately the center of the linear region of the ignition timing/torque characteristics. There is. Due to the occurrence of the deviation ΔN, ignition timing feedback control is performed, the ignition timing is changed to an advanced direction or a retarded direction, and the deviation ΔN is reduced.

Next, the intake air amount is feedback-controlled based on the feedback amount of the ignition timing control so that the feedback amount is reduced, so that the deviation ΔN is further reduced. As a result, the amount of feedback for ignition timing control is reduced, and the ignition timing is changed to a new ignition timing that is closer to the normal ignition timing. Thereafter, while ignition timing feedback control is performed in the same way, intake air amount feedback control is performed in the direction of reducing the burden of ignition timing feedback control, and finally the deviation Δ
N#0, and the ignition timing is returned to the original regular ignition timing.

In this way, while the ignition timing feedback control provides feedback control to reduce the deviation ΔN with high responsiveness, the intake air amount feedback control takes over so that the feedback amount of the ignition timing feedback control is reduced. The ignition timing can be returned to the normal ignition timing.

Therefore, idle speed control can be executed with high responsiveness,
In addition, the ignition timing can be returned to the normal ignition timing,
As a result, it is possible to reliably eliminate the deviation ΔN caused by an increase or decrease in load, improve idling stability, and prevent deterioration of fuel efficiency.

〔Effect of the invention〕

According to the idle rotation speed control device according to the present invention, the above [
As explained in section 2.1, "Operation", by providing the feedback amount detection means and the feedback amount setting means, the ignition timing feedback control and the intake air amount feedback control are not performed independently of each other, but the ignition timing feedback control is performed. By subordinating the intake air amount feedback control to the engine speed, the ignition timing can be returned to the normal ignition timing at an early stage, thereby significantly improving engine idle stability and preventing deterioration of fuel efficiency. is obtained.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

This embodiment is a case where the present invention is applied to an idle speed control device for a vertical four-cylinder engine for an automobile.
Cylinder block 1, cylinder head 2, piston 3, combustion chamber 4, intake boat 5, intake valve 5 in engine E
The configurations of the AS exhaust boat 6, the exhaust valve 5a's spark plug 7, the injector 8, the intake passage 9, the exhaust passage 10, etc. are the same as those of a general automobile engine, so detailed explanation thereof will be omitted.

As shown in FIG. 1, the cylinder block 1 is provided with a water temperature sensor 12 that detects the temperature of cooling water in its water jacket la, and a hot wire that detects the amount of intake air is provided at the upstream portion of the intake passage 9. type air flow meter 14
is interposed, and a throttle valve 15 is provided in the middle of the intake passage 9.
The throttle valve 15 is provided with a throttle opening sensor 16 for detecting its opening, and an idle switch that turns on when the throttle valve 15 is fully closed. Signals from the sensor 16 and the idle switch are input to the control unit 11. Throttle valve 1
A bypass passage 17 is provided to bypass the idle speed control (I).
An idle control valve 18 controlled by a linear solenoid is provided for SC), the opening degree of the idle control valve 18 is controlled by the control unit 11, and the amount of intake air supplied from the bypass passage 17 is precisely controlled. Ru.

Ignition device 1 for igniting the four spark plugs 7 of the engine E in a predetermined order and at controlled timing
9 and a distributor 20 are provided, and the ignition device 1
Reference numeral 9 includes an ignition control circuit and an ignition coil, and generates a high voltage in response to signals IGTS and IGW that command ignition timing and energization time from the control unit 11, and the high voltage is transmitted to the four spark plugs 7 by a distributor 20. Power is distributed to

The distributor 20 includes a disk fixed to a rotary shaft that rotates in synchronization with the crankshaft and an electromagnetic pickup, and a crank angle signal C8 is generated every 1806 revolutions of the crankshaft.
A crank angle sensor is provided that outputs this to the control unit 11.

Further, the control unit 11 receives signals from a neutral position switch 22 provided in the transmission, and drive switches 23 for the air conditioner, power steering, electrical loads, etc. that act as external loads for the engine E.
Signals from 24 etc. are also output.

As shown in FIG. 2, the control unit 11 receives detection signals from various sensors 12, 14, 16 and signals from various switches 22 to 24, etc., and performs A/D conversion as necessary. Input port 25 for waveform shaping
and a bus 26 including a data bus, an address bus, etc.
CPU27 (central processing unit) and ROM28 (read/
only memory) and RAM29 (random access
It is equipped with a microcomputer consisting of a memory), an output boat 30, a drive circuit 31 for the injector 8, a drive circuit 32 for the idle control valve 18, a drive circuit 33 for the ignition device 19, etc. In the ROM 28, a control program for idle speed control, which will be described later, various memory maps necessary for this control, and other control programs and memory maps necessary for controlling the engine E are input and stored in advance.

Here, as shown in the functional block diagram of FIG. 2A, the idle speed control device of the present application controls the engine speed so that the engine speed N becomes the target idle speed N0 when the engine E is in an idling operating state. The ignition timing is feedback-controlled based on the deviation between the engine speed N and the target idle speed N0, and the amount of intake air supplied from the bypass passage 17 is controlled by a feedbank so that the feedback control amount of this ignition timing control is reduced. It is something to control.

The idle rotation speed control routine executed by the control unit 11 will be explained based on the flowcharts of FIGS. 3 to 5.

This idle speed control basically consists of an ignition timing control routine and an intake air amount control routine, and the ignition timing control is executed by interrupt processing every time the crank angle signal CS is input, that is, every 1806 revolutions of the crankshaft. The intake air amount control is executed by interrupt processing every fixed period of time (for example, 100 m5ec), and Si (i=1.2.
3...) indicates each step.

First, regarding the ignition timing control routine, see Figures 3 and 4.
The explanation will be based on the flowchart shown in the figure.

When this control is started every time the crank signal C8 is input while the engine E is running, the crank signal C8 is read and used to calculate the engine rotation speed N (Sl), and the air intake from the air flow meter 14 is calculated. The air amount signal is read and used to calculate the average intake air i1Q for one stroke (S2), and the filling efficiency C0 is calculated as C, = K - Q, /
(S3) where K is a predetermined constant.

Next, the basic ignition timing θ5 is calculated from the memory map shown in FIG. 6 stored in the ROM 28 using the engine speed N0 and the charging efficiency C1 (S4). In addition, THTB
ASE indicates the starting address of the memory map stored in ROM2B. Next, it is determined whether the engine is in an idle state or not, and the idle switch of the throttle valve 15 is ON and the engine speed N is, for example, N, S80°r.
pm and the neutral position switch 22 is ON.
When this happens, it is determined that the vehicle is in an idle state (S5).

During idling, the ignition timing retard amount θ is determined from the memory map shown in FIG.
(S6).

Incidentally, THTRET indicates the starting address of the memory map stored in the ROM 28. If the result of the determination in S5 is that the vehicle is not in the idle state, the retard amount θ is set to 0, and the process moves to S7. Next, the deviation ΔN between the engine speed N1 and the target idle speed N0 (ΔN=NO−N,)
Ignition timing feedback amount θ2 to correct
．． And the calculation process of the average feedback amount 7fb is executed (S7). Furthermore, this average feedback Her
b is used in intake air amount feedback control, which will be described later, as a feedback control amount of ignition timing feedback control.

This arithmetic processing in S7 is shown in the flowchart of FIG.
), in the case of the idle region, the target idle rotation speed N is calculated using the cooling water temperature T on the basis of the memory map shown in FIG. 10 stored in the ROM 2B (311),
Furthermore, the ignition timing feedback amount θ1. is the above deviation ΔN
(S12). In addition, THTFB and T
NO indicates the start address of the memory map stored in ROM2B. Next, the average feedbank amount f
313 to S17 as a routine to obtain 'tb
The routine then moves to S8, but this routine is not directly related to ignition timing control and will be described later.

When the ignition timing feedback amount θfb is calculated, the final ignition timing θi9 for igniting the spark plug 7 is calculated as θ19''θ from the basic ignition timing θ5, the ignition timing retard amount θ, and the ignition timing feedback amount θ,1. , -θ, +θt
It is calculated using the formula b (S8), and the control unit 11
This ignition timing θ8. The ignition command signal IGTS-IGW is outputted to the ignition device 19 at a timing corresponding to , and the spark plug 7 is ignited. In other words, when driving at idle,
As shown in Fig. 9, in order to correct the decrease in engine speed N due to external load etc. by adjusting the ignition timing, the ignition timing is delayed by the ignition timing retard amount θ with respect to the basic ignition timing θ1 in advance, and the target idle Rotation speed N. The ignition timing feedback amount θ is based on the deviation ΔN between the engine speed N and the engine speed N. By adjusting , the engine rotation speed N is corrected according to the deviation ΔN.

During driving, the ignition timing retard amount θ.

is set to θ1=0 (S9), the ignition timing feedback amount θ,b and its average feedback amount Tf, are set to θfb=O, Tfb=O (S18), and the final ignition timing θ5 is the basic ignition. The time is set to θゎ (S8)
, ignition timing θi, which is close to the best torque advance angle.

After the ignition timing control routines of S1 to S9 and SIO to i8 are completed, the process returns to the main routine.

Next, a routine for obtaining the average feedback '1ketb as the feedback control amount for ignition timing control will be explained with reference to FIG.

If it is not in the idle state, the process moves to S17 via 318, and in S17 the cumulative feedback amount stb is 5.
tb=0 is set, and a soft subtraction counter C provided in the memory of the RAM 29 is set to C=N. The above N indicates the cumulative number of times the ignition timing feedback amount θ,1 is accumulated, and is set to N=10, for example. Every time ignition timing control is executed during idle operation,
The process moves to S13 via Sll/S12, but since the counter C is not zero at the beginning, the process moves to 314, and in S14, the current ignition timing feedback amount θ, b is added to the previous cumulative feedback It S t b. The cumulative feedback amount stb is calculated, and then the counter value C is decremented (S15). Then, when the ignition timing control routine is executed a predetermined N times and the counter value C becomes C=0, it is determined as Yes in S13, and the average feedback amount etb is calculated using the cumulative feedback amount Sfb to be equal to fb=Sfb/N. It is calculated using the formula (316).

Next, the cumulative feedback amount S for the next N cumulative restarts
fb is set to 5tb=O, and the counter (direct C) is set to C=N (S17), and in this way, every time the ignition timing control routine is executed N times, the average feedback amount Tfb
is calculated, and this value is temporarily stored in the memory of the RAM 29.

Next, an intake air amount control routine for controlling the amount of bypass air via the idle control valve 18 will be explained based on the flowchart of FIG.

This intake air amount control is performed for a certain period of time (for example, 100m5ec).
) is performed as an interrupt process every time. First, the throttle opening Tv detected by the throttle opening sensor 16 and the water temperature sensor 12, respectively.

and the cooling water temperature T are read and stored in the memory of the RAM 29 (520). Next, the minimum basic bypass air NQb required to maintain the target idle rotation speed N0 in a state where no external load is applied is determined by the ROM2B
It is calculated from the cooling water temperature Thw based on the memory map shown in FIG. 11 stored in the memory map shown in FIG. 11 (S21). Furthermore, QBASE
indicates the start address of the memory map stored in ROM2B.

Next, each corrected amount of bypass air corresponding to the external load such as the air conditioner or power steering that is currently being driven is read out from the table in the ROM 28 that accompanies this control program, and the corrected amounts of bypass air are summed up and corrected. Bypass air amount Q.

is calculated (322).

Next, it is determined whether or not it is in an idling state (S23), and if it is in an idling state, the adjustment amount Qf of the intake air amount is first determined from the memory map shown in FIG. 12 stored in the ROM 28.
bi is calculated using the average feedback amount atb of the ignition timing, and the previous bypass air feedback 1lQ1. is added to calculate the current bypass air feedback amount Qfb (S24).

Next, from the basic intake air amount Q, the corrected bypass air amount Q0, and the bypass air feedback amount Qtb, the final bypass air amount Q, c is calculated as Q+sc =Qb+Q@+Qf
The idle control valve 18 is driven by the control unit 11 based on the final bypass air amount Q, , c (S26), and the amount of intake air supplied from the bypass passage 17 is controlled. In other words, the basic intake air amount Qb
The minimum required amount of intake air necessary to run the engine E in idle mode is secured, and the amount of intake air is increased with the corrected bypass air amount Q so that the engine speed N8 does not decrease with respect to the external load. Average feedback amount Tf of ignition timing with bypass air feedback t Q t b
The amount of intake air is controlled so that b decreases.

If the result of the determination in S23 is that the vehicle is not in the idle state, the process proceeds to S25, where Qrb=O is set, and the process proceeds to S26.

As mentioned above, the ignition timing control performed every 180° rotation of the crankshaft corrects fluctuations in the engine speed N0 with high responsiveness, and the ignition timing is corrected by the intake air amount control performed every predetermined time. Since the feedback amounts θ and b are adjusted stepwise to decrease and the engine speed N0 is corrected to the target idle speed N0, the engine speed N,
Even if N changes, the engine speed N can be quickly corrected by highly responsive ignition timing control. Moreover, the 12th
Since the memory map shown in the figure is not provided with a dead zone, the engine speed N is reliably controlled so as to reach the target idle speed N0.

Here, the simulation results of idle rotation speed control by the above-mentioned idle rotation speed control device will be explained based on the time chart of FIG. 13.

When the throttle valve 14 is fully closed by interrupting the operation of the accelerator pedal, the engine speed N rapidly drops with the transition from driving operation to idling operation, and the engine speed N becomes the target idle speed N0. The value is significantly lower than At this time, first, the ignition timing feedback amount θ,b is largely adjusted to the advance side based on the deviation ΔN between the engine speed N and the target idle speed N0, and this ignition timing feedback amount θt1 is fed back to respond. The drop in engine speed N0 is quickly suppressed by highly efficient ignition timing control. Then, the average feedback 1lTfb within a predetermined time is calculated, and this average feedback t
The bypass air feedback amount Qfb is increased so that Tfk decreases, and as a result, the ignition timing feedback amounts θ and b are decreased, and the deviation ΔN between the target idle speed N0 and the engine speed N is reduced by the intake air amount control. do. This bypass air feed bank
Adjustment of Q t b takes a predetermined time (for example, 100 m5ec)
It can be seen that the ignition timing feedback amount θf, , is gradually decreased, and the engine rotational speed N is gradually corrected to the target idle rotational speed N0.

Note that the bypass passage 17 and the idle control valve 18 are omitted so that the throttle valve 15 can be precisely controlled by a linear solenoid actuator at least in the idle state, and the intake air amount is feedback-controlled via the throttle valve 15. The present invention can be similarly applied to those of this type.

[Brief explanation of drawings]

Among the drawings, FIGS. 1 to 13 show embodiments of the present invention. FIG. 1 is an overall configuration diagram of an automobile engine and its idle speed control device, and FIG. 2 is an illustration of the idle speed control device. The overall configuration of the control system, Figure 2A is a functional block diagram of idle speed control, Figure 3 is a flowchart of the ignition timing control routine, Figure 4 is a flowchart of the ignition timing feedback calculation routine, and Figure 5 is a flowchart of the ignition timing control routine. The figure is a flowchart of the intake air amount control routine, Figure 6 is a diagram showing the basic ignition timing map with charging efficiency and engine speed as parameters, and Figure 7 is a diagram showing the relationship between cooling water temperature and ignition timing retard amount. A diagram showing the relationship, Figure 8 is a diagram showing the relationship between rotation speed deviation and ignition timing feedback amount, Figure 9
Figure 10 is a diagram showing the relationship between ignition timing and engine speed, Figure 10 is a diagram showing the relationship between cooling water temperature and target idle rotation speed, and Figure 11 is a diagram showing the relationship between cooling water temperature and basic bypass air amount. Figure 12 is a diagram showing the relationship between the average feedback amount and the adjustment amount of the bypass air amount, and Figure 13 is a diagram showing the relationship between the engine speed, the ignition timing feedback amount, the average feedback amount, and the bypass air feedback amount. The time chart, FIG. 14, is a diagram showing the relationship between ignition timing and torque according to the prior art. E...Engine, 11...Control unit,
14... Air flow meter, 18... Idle control valve, 19... Ignition device, 20... Distributor. Patent applicant: Mazda Motor Corporation Figure 2A Figure 4 Figure 3 Figure 5 Figure 6 Figure 8 Figure 7 Figure 9 Figure Ignition timing

Claims (1)

[Claims] (1) Ignition timing adjustment means for adjusting the ignition timing, intake air amount adjustment means for adjusting the intake air amount, rotation speed detection means for detecting the actual rotation speed of the engine, and actual rotation speed detected by the rotation speed detection means In an engine idle speed control device comprising an ignition timing control means and an intake air amount control means that perform feedback control of the ignition timing adjustment means and the intake air amount control means, respectively, so that the ignition timing control means achieves a target idle speed. a feedback amount detection means for detecting a feedback amount for ignition timing control; and upon receiving the output of the feedback amount detection means, setting a feedback amount for intake air amount control in the intake air amount control means so that the feedback amount for ignition timing control is reduced. What is claimed is: 1. An engine idle speed control device comprising: feedback amount setting means for controlling an engine idle speed;