JPH02149749A - Control device for idle rpm of engine - Google Patents

Abstract

PURPOSE:To stabilize an engine at the target number of idle revolutions with excellent responsiveness by limiting the feedback values, except for executing learning control, of intake quantity and of spark-advance quantity of ignition timing within a fixed range under fixed conditions for executing the learning control. CONSTITUTION:When a distinguishing means 31 has distinguished an idle operational state of an engine, a control means 32 executes the feedback controls of intake quantity and of the spark-advance quantity of ignition timing so that the number of revolutions of the engine may converge on a target value, and a learning control executing means 34 executes the learning control of either of the intake quantity and the spark-advance quantity on the feedback value of the above feedback control. In this case, when a distinguishing means 33 judges the engine to be under a fixed condition for executing the learning control, a limiting means 35 limits the feedback value, except for executing the learning control, of the intake quantity and of the spark-advance quantity within a fixed range. Thus, when the engine has been changed over from open control to the feedback control, the feedback control begins from an approximately aimed state of the number of idle revolutions. The engine can be therefore stabilized at the target number of idle revolutions with excellent responsiveness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an engine idle speed control device that performs feedback control and learning control of the idle speed.

[Conventional technology]

Conventionally, as engine idle speed control flR1, in order to make the engine speed converge to the target speed during idling operation, feedback control of the intake air amount and ignition timing advance control have been used. It is known as feedback control. The former idle speed control device that performs feedback control of the intake air amount can control the idle speed over a wide range, but on the other hand,
It has the disadvantage of poor responsiveness. On the other hand, the idle speed system (which controls the amount of advance of the latter's ignition timing by feedback)
Although the Il device has good responsiveness, it has the disadvantage that it cannot be controlled over a wide range.

Therefore, in order to take advantage of each other's strengths and compensate for their weaknesses, both the intake m and the ignition timing advance are feedback-controlled, making it possible to control the idle speed with good responsiveness over a wide range. A device having the following structure has been developed (see Japanese Patent Publication No. 61-53544).

On the other hand, as a conventional engine idle speed control method, feedback control is performed to converge the engine speed to a target speed when the engine is in an idling state, and the feedback control is performed under predetermined conditions. A known method is to sequentially import feedback values into a table, store them as learned values in the table, and use the learned values to perform feedback control (1111), that is, to perform learning control (Japanese Patent Application Laid-Open No. 1983-1993). -3
(See Publication No. 1645).

According to this learning control method, as shown by the solid line in Figure 6, when switching from the oven control zone to the feedback control zone that controls the idle speed, the idle speed is controlled in the previous feedback control zone. The feedback value obtained is stored as a learning value, and the current feedback control is started from that learning value, so the idle rotation speed quickly converges to the target rotation speed, and when learning control is not performed. This makes it possible to eliminate the response delay that occurs (indicated by the broken line in FIG. 6).

[Problem to be solved by the invention]

However, when the above learning control method is applied to a control device that performs feedback control on both the intake air amount and the ignition timing advance amount, one of the intake air amount and the ignition timing advance amount, for example, the intake air amount, is feedback-controlled. When learning control is performed based on values, the following problems occur.

In other words, in general, in feedback control, the feedback value cannot be obtained immediately after switching from the oven control zone to the feedback control zone.
The feedback value is O. Therefore, in the case of the above configuration, immediately after switching from the oven control zone to the feedback control zone, for example, when the basic intake air amount is less than the required intake air amount, as shown in FIG. 5(a), In order to secure the intake air ff1H necessary to maintain the target rotational speed, the learning value Qlrn1 for [required intake air amount H - basic intake air ff1Gb J] needs to be read out.

However, in the above configuration, since both the intake air amount and the ignition timing advance amount are feedback-controlled, the ignition timing advance amount is influenced by the feedback value of the ignition timing advance amount on the side where learning control is not performed. , the feedback value of the intake air amount on the side where learning control is performed is suppressed, and this is stored as a learning value. Therefore, in reality, Fig. 5(b)
As shown in , ff1G(θr
b> A very small number of learned values Glrn were read out. Therefore, immediately after switching from the oven control zone to the feedback control zone, the required learning 1iQl
The idle speed is controlled using the learned value Qlrn, which is smaller than rn1, and because the learned value is insufficient, it takes time to converge to the target idle speed.

In this engine idle speed control device that performs feedback control on both the intake air amount and the ignition timing advance amount, one of the intake air amount and the ignition timing advance amount is controlled by learning based on the feedback value. If this is done, the learning value will decrease due to the influence of the feedback value on the side where learning control is not performed, and even if learning control is performed, the control will be affected when switching from oven control to feedback control. Responsiveness could not be improved sufficiently.

In view of the above circumstances, the present invention provides feedback control for both the intake air amount and the ignition timing advance m, and also performs learning control on one of the intake air amount and the ignition timing advance based on the feedback value. An object of the present invention is to provide an engine idle speed control device that can improve control responsiveness when switching from oven control to feedback control.

[Means to solve the problem]

The engine idle speed control device according to the present invention includes:
As shown in FIG. 1, feedback control means performs feedback control on the amount of intake air and the amount of advance of the ignition timing so that the engine speed converges to the target speed under a predetermined condition corresponding to an idling operating state. 32, and learning control execution means 34 for learning and controlling one of the intake air amount and the ignition timing advance amount based on the feedback value when the learning control is performed under a predetermined condition. The device is provided with a feedback value limiting means 35 for limiting feedback values other than those for performing learning control among the intake air amount and ignition timing advance amount to within a predetermined range when the learning control is performed under a predetermined condition. It is something.

[Effect]

According to the above configuration, under the predetermined conditions for performing learning control, the feedback value limiting means suppresses the feedback value on the side where learning control is not performed among the intake air amount and ignition timing advance angle. . Therefore, the decrease in the feedback value on the side where learning control is performed (stored as a learned value), which would otherwise be reduced due to the influence of the feedback value on the side where learning control is not performed, is suppressed, and as a result, the learning ! This means that the decrease in ff1a is suppressed.

〔Example〕

FIG. 2 shows a schematic structure of an embodiment of an engine idle speed control device according to the present invention. In this figure, an air cleaner 3, an air flow meter 4 for detecting the amount of intake air, a throttle valve 5, a surge tank 6, and a fuel injection valve 7 are disposed in order from the upstream side in an intake passage 2 of an engine 1.

In addition, a bypass passage 8 is provided in the intake passage 2, and an ISC valve 9 that adjusts the amount of intake air passing through this passage 8 (auxiliary intake air amount) to adjust the engine rotation speed is installed in the bypass passage 8. There is. Further, the intake passage 2 and the engine 1 include a throttle opening sensor 10 that detects the opening of the throttle valve 5, and an intake temperature sensor 1 that detects the intake air temperature.
The exhaust passage 15 of the engine 1 is equipped with an exhaust temperature sensor 16 that detects the exhaust gas temperature.

Reference numeral 30 denotes an engine control unit (ECU) to which detection signals from the air flow meter 4 and each sensor 10 to 12.16 are input, and which is installed in the distributor 13 of the ignition system. Signals are also input from a rotational speed sensor 14 that detects the engine rotational speed, an external load sensor 17 that detects an external load such as a near conditioner, and a crank angle sensor 18 that detects a crank angle. The control unit 30 sends control signals to the igniter 20 that drives the spark plug, the fuel injection valve 7 and the ISG valve 9 to control the ignition timing, and control signals to control the fuel injection amount and fuel injection timing. , and a control signal for adjusting the auxiliary intake air amount.

As shown in FIG. 1, the engine control unit 30 includes an idle operation state success/failure determination means 31, a feedback control means 32, a learning control execution condition success/failure determination means 33, a learning control execution means 34, and a feedback control
a amount limiting means 35.

The idling state success/failure determining means 31 determines whether or not a predetermined condition corresponding to an idling state is present based on detection signals from the throttle opening sensor 10, rotation speed sensor 14, and the like.

The feedback control means 32 has an intake air amount feedback control means 321 and an ignition timing advance angle feedback control means 322, and these determine that the idle operation state success/failure determination means 31 is under a predetermined condition corresponding to an idle operation state. The amount of intake air and the amount of advance of the ignition timing are feedback-controlled so that the rotational speed of the engine 1 converges to the target rotational speed when the engine 1 is rotated. That is, in the idling state, the feedback value of the intake air amount and the advance amount of the ignition timing are adjusted according to the difference between the actual rotation speed of the engine 1 detected by the rotation speed sensor 14 and the preset target rotation speed. A command signal corresponding to each feedback value is output to the ISC valve 9 and the igniter 20, respectively, to increase or decrease the amount of auxiliary intake air j and the amount of advance of the ignition timing.

The learning control execution condition success/failure determining means 33 is configured to determine whether or not a predetermined condition for performing academic gate control is met.

The learning sub-part execution means 34 determines one of the intake air amount and the ignition timing advance amount based on the feedback value when the learning control execution condition success/failure determination means 33 determines that the predetermined condition is under which learning control is performed. It is designed to be controlled by learning. In this embodiment, the intake air amount is controlled by learning.

The feedback value limiting means 35 is configured to set feedback values other than those for performing the learning control among the intake air amount and the ignition timing advance amount when the learning control execution condition success/failure determining means 33 determines that the predetermined condition is such that the learning control is performed. That is, in this embodiment, the feedback value of the amount of advance of the ignition timing is limited within a predetermined range.

FIG. 3 shows a specific example of control by the control unit 30. Note that this control is repeated at predetermined intervals.

In this flowchart, first, in step S1,
Air flow meter 4, throttle opening sensor 10. Various signals are read from the intake temperature sensor 11, water temperature sensor 12, rotation speed sensor 14, exhaust temperature sensor 16, external load sensor 17, etc. Next, in step S2, it is determined whether the vehicle is in the feedback control zone, that is, whether the vehicle is under a predetermined condition corresponding to an idling state. This includes, for example, a condition that the throttle opening sensor 10 detects that the throttle valve 5 is fully open, and a condition that the rotation speed sensor 14 detects that the rotation speed of the engine 1 is below a predetermined rotation speed. When the above conditions are satisfied, it is determined that the predetermined condition corresponds to an idling operating state. If even one of the above conditions is missing, it is determined that the predetermined condition corresponding to an idling operating state is not present.

When it is determined in step S2 that the predetermined condition corresponds to the idling operating state, in step S3 and step S4, the current intake air amount feedback value Gfb and the ignition timing advance amount are fed back based on the formula shown in the figure. The value θrb is determined. In addition, in step S3 and step S4, (3fb(1-1) is the feedback value of the previous intake air amount, Ne is the actual rotation speed of engine 1, No is the target rotation speed of engine 1, and ΔGfb is the target rotation of engine 1. The change amount C/250 in the intake air amount feedback value according to the difference between the number No. and the actual rotation speed Ne is a calculation coefficient for calculating the ignition timing advance amount from the difference in rotation speed.

After executing step 84, it is determined in step S5 whether or not the learning control zone exists, that is, whether or not the predetermined conditions for performing learning control are met. In addition to the condition of being under the predetermined condition corresponding to the above-mentioned idling operating state, for example, the condition that the external load is turned off by the external load sensor 17, and the condition that the water temperature of the cold part of the engine by the water temperature sensor 12 is higher than a predetermined value. , and the target rotation speed NO and actual rotation speed N of engine 1.
When the condition that the difference with e is equal to or less than a predetermined value is satisfied, it is determined that the predetermined condition is that learning control is performed;
If even one of the above conditions is missing, it is determined that the predetermined conditions for performing learning control are not met.

If it is determined in step $5 that the predetermined conditions for performing learning control are not met, in step S6 the feedback value θ'b of the ignition timing advance amount changes from the lower limit θ1m1n to the upper limit θfb.
It is determined whether it is within the range up to max. θrb is θfb
If it is within the range from min to θfbmax, step S19 is performed without changing θrb in step S7.
Execute. Also, θ"b is from θfbmin to θfbm
If it is outside the range up to ax, θrb is set to θ in step S8.
Determine whether θrb is larger than fbIIlax, and determine whether θrb is larger than θ
If it is larger than fbmax, in step S9 θ'b is set to θfbmax, then step S19 is executed, and θ
If rb is not larger than θfbmax, that is, θrb is smaller than θfbi+in, θ
Step S19 is executed after setting rb to θfbmin. However, θfblin < Q < θfbmax, and the range from θrb1n to θfbmax is set to a relatively wide range without exceeding the ignition timing variation tolerance range.

On the other hand, if it is determined in step S5 that the predetermined conditions are met for performing learning control, it is determined in step S11 whether or not the number of sampling times has reached a predetermined number. In this embodiment, the predetermined number of times is set to 64 times. Then, when it is determined in step S++ that the number of samplings has reached 64, in step S12, the average value (
After calculating the learning value Qlrn of the intake air amount by adding half of Gfb) to the previous learning value Glrn(1-1>), step S°C is executed.Meanwhile, the number of samplings reaches 64 in step S11. If it is determined that the intake air amount is not the same, step S is skipped and step S13 is executed. Therefore, the learned value Qlrn of the intake air amount is updated every time this control is repeated 64 times. The learned value Qlrn of the intake air amount is memorized in the table.

In step S13, Gfb is the lower limit value θrbm+n
It is determined whether it is within the range from i to the upper limit value θfbmaxl. However, θfbmln <θla+inl<
θ1w+ax1 θfbmax, 01m1n1~G
The range of fbrAax1 is θfbmin to θfbla.
Set narrower than the range of x.

In step St3, Gfb changes from θfblinl to θrbm.
When it is determined that Gfb is within the range up to ax1, the process proceeds to step S1 without changing Gfb in step S14.
Execute step 9. Also, in step St3, Gfb is θfb
When it is determined that Gfb is outside the range from min1 to θfba+ax1, Gfb is set to θ1ma in step S15.
Determine whether Gfb is larger than x1 and determine whether Gfb is θfbila
If it is larger than X1, Gfb is set to θf in step S16.
After setting bmaxl, step Ss is executed, and if Gfb is smaller than θfbmin1, in step S1e, Gfb is set to θfbminl, and then step S19 is executed.

Further, when it is determined in step S2 that the predetermined condition corresponding to the idling operation state is not established, step Ssa
After setting Gfb and Gfb to 0, step S19 is executed.

In step S19, other various correction amounts, that is, a load correction IG+ according to the magnitude of the load, a dashpot correction it Gdo, a cooling water temperature correction amount θthw according to the engine cooling water temperature, and an external load correction amount θ1 are determined.

Then, step 820 is executed, and the correction IGI, Qdp, Gfb obtained above and Glrn stored in step St2 are converted into the basic intake amount Gb by the atmospheric pressure correction coefficient C.
The final intake air ff1Ga is obtained by adding the value multiplied by atpi, and the correction amounts θfb and θthw obtained above are
, θ1 are added to the basic ignition timing advance amount θid to obtain the final ignition timing advance θig.

After determining the final intake mGa and the final ignition timing advance amount θig in step S20, a command signal corresponding to the final intake mGa and final ignition timing advance mθQ is outputted to the ISC valve 9 and the igniter 20 in step S321. After that, the process returns to step S1, and thereafter, the control from step S1 onwards is repeated.

As shown above, in the control of the above flowchart, as shown in FIG.
If it is determined that the predetermined condition is under which learning control is performed in step 5, the feedback value θfb of the ignition timing advance amount is larger than the relatively wide range from the lower limit value θfbw+in to the upper limit value θ1max in the feedback control zone. From the small lower limit value θrbmin1 to the upper limit value θfblaX1
It is now limited to a range of up to

In this way, in the learning control zone, since the feedback value θ'b of the ignition timing advance amount is suppressed, the feedback value Gfb of the intake air amount increases by that amount, and as a result, the learning 11Glrn of the intake air amount increases to a large value. In other words, 1tG (Gfb), which corresponds to the feedback value of the ignition timing advance m shown in FIG. 5(b), is suppressed.
Learning of intake air volume [Decrease in Qlrn can be suppressed. Therefore, when switching from open control to feedback control, feedback control is performed from a state corresponding to the target idle speed, and it quickly converges to the target idle speed. .

In the feedback control zone, the feedback value θrb of the ignition timing advance amount is set so as not to exceed the ignition timing variation tolerance range (θfb1n to θfbma).
Therefore, it is possible to prevent the ignition timing advance amount from becoming too large or too small, thereby preventing deterioration of combustibility, etc.

In the present invention, the ignition timing advance amount may be subjected to learning control instead of the intake air amount. However, in this case, the feedback value limiting means limits the feedback value of the intake air amount within a predetermined range.

〔Effect of the invention〕

The engine idle speed control device according to the present invention includes:
When the learning control is performed under a predetermined condition, the feedback value limiting means suppresses the feedback value of the intake air amount and ignition timing advance amount on the side where the learning control is not performed, so that the learning value decreases. You will be able to control it.

Therefore, when switching from oven control to feedback control, feedback control is performed from a state corresponding to the target idle rotation speed, and the target idle rotation speed is stabilized with good responsiveness. Become.

[Brief explanation of the drawings] Figure 1 shows the idle speed υ1 of the engine according to the present invention.
111 is a block diagram showing the basic configuration of an embodiment of the device, FIG. 2 is a schematic structural diagram of the device, FIG. 3 is a flowchart showing a specific example of control, and FIG. 4 is an ignition timing advance amount in the feedback control zone. 5(a) and (b) are explanatory diagrams showing the theoretically required learning value and the actual learning value immediately after switching to the feedback control zone, respectively. , FIG. 6 is a time chart showing changes in engine rotational speed ma in the feedback control zone and the oven control zone. DESCRIPTION OF SYMBOLS 1... Engine, 32... Feedback control means, 34... Learning control execution means, 35... Feedback value limiting means. Patent applicant Mazda Co., Ltd. Agent Patent attorney Etsushi Kotani otb Figure (a) Figure (b)

Claims (1)

[Claims] 1. Feedback control means for feedback controlling the intake air amount and ignition timing advance amount so that the engine speed converges to the target speed under a predetermined condition corresponding to an idling operating state, and learning control. In an engine idle speed control device comprising a learning control execution means for learning and controlling one of the intake air amount and the ignition timing advance amount based on a feedback value under a predetermined condition, An idle speed of an engine characterized by being provided with feedback value limiting means for limiting feedback values other than those for which learning control is performed among the intake air amount and the ignition timing advance amount to within a predetermined range under the following conditions. Number control device.