JPH09170475A - Idle rotational speed learning controller for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve learning frequency in the learning of the changed part of a leakage air amount when a throttle valve is fully closed. SOLUTION: A speed reducing operation condition when a throttle valve is fully closed is detected (S24). Next, at the time of the speed reducing operation, deviation ΔQ between an inlet air flow Q detected by an airflow meter (S25) and a target value Qs according to an engine rotational speed (S26) is detected (S27). Then, the deviation ΔQ is converted into duty as the control amount of an auxiliary air control valve (S28) so as to update a learning correction amount on the basis of the converted value (S29).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine idle rotation speed learning control device, and more particularly to an idle rotation speed learning control device capable of learning and correcting a leak air amount change amount when a throttle valve is fully closed.

[0002]

2. Description of the Related Art Conventionally, an automobile engine is equipped with an auxiliary air control valve in an auxiliary air passage that bypasses a throttle valve in an intake passage, and compares an actual idle speed with a target idle speed during idle operation. The idle rotation speed is feedback-controlled by controlling the opening of the auxiliary air control valve according to the comparison result.

Further, as disclosed in Japanese Patent Publication No. 19295/1990, a learning correction amount is set on the basis of a feedback correction amount set for feedback control of the idle rotation speed under a predetermined condition, and the learning is performed. It is also known that the opening degree of the auxiliary air amount control valve is corrected by the correction amount to perform more advanced learning control. Further, such a learning correction amount is also made to correspond to the amount of change in the leaked air amount (clogging amount) when the throttle valve is fully closed.

[0004]

By the way, in the conventional idle speed learning control device, the air when the throttle valve is fully closed is based on the feedback correction amount set for the feedback control of the idle speed. When learning the leakage change amount, there is a problem that the learning accuracy is reduced due to the influence of the air conditioner ON / OFF, the transmission range (N range / D range), the electric load, and the like. Therefore, in the past, in addition to the feedback control, the air conditioner is turned off, the N range is turned off, and the electric load is turned off.
The learning accuracy is ensured by performing the learning only when the learning conditions such as the above are satisfied.

However, if the learning conditions are made strict in order to secure the learning accuracy as described above, there is a problem that the learning frequency becomes low and the learning does not progress easily. The present invention has been made in view of the above problems, and in learning a learning correction amount corresponding to the amount of leak air when the throttle valve is fully closed, it is possible to increase the frequency of learning while ensuring learning accuracy. The purpose is to be able to.

[0006]

For this reason, in the invention according to claim 1, an engine having an auxiliary air control valve in an auxiliary air passage bypassing the throttle valve of the intake passage is provided with a means as shown in FIG. The idle rotation speed learning control device. In FIG. 1, the feedback correction amount setting means compares the actual idle rotation speed and the target idle rotation speed during idle operation, and sets the feedback correction amount according to the comparison result.

The learning correction amount storage means is a rewritable storage means for storing the learning correction amount corresponding to the amount of change in the leaked air amount when the throttle valve is fully closed. Here, the control amount calculation means calculates the control amount for the auxiliary air control valve based on at least the feedback correction amount and the learning correction amount. Then, the auxiliary air control valve drive means opens and closes the auxiliary air control valve by a signal corresponding to the control amount.

On the other hand, the deceleration detection means detects a predetermined deceleration operation state when the throttle valve is fully closed, and the learning correction amount updating means sucks the engine when the deceleration operation state is detected by the deceleration detection means. The learning correction amount in the learning correction amount storage means is updated based on the difference between the detected value of the parameter correlated with the air amount and the target value of the parameter. With this configuration, if there is a change in the amount of leaked air when the throttle valve is fully closed, it will be correlated to the intake air flow rate, negative suction pressure, in-cylinder pressure, etc. of the engine during deceleration operation when the throttle valve is fully closed. A change in the leaked air amount is learned from the difference between the preset parameter and the target value (value in the initial state). Therefore, learning can be performed not only during feedback control of the idle rotation speed but also during deceleration, and the learning frequency can be improved.

In the second aspect of the present invention, in the learning correction amount updating means, the parameter correlated to the intake air amount of the engine is the intake air flow rate of the engine, and the detected value of the intake air flow rate and the target value are set. The difference is converted into a control amount for the auxiliary air control valve, and the learning correction amount of the learning correction amount storage means is updated based on the converted control amount.

According to this structure, the change in the intake air flow rate during deceleration with the throttle valve fully closed is proportional to the change in the effective opening area of the intake system (clogging). And the target value) are converted into a control amount for the auxiliary air control valve, the clogging amount (change amount of leak air amount when the throttle valve is fully closed) can be learned as the control amount.

In the third aspect of the present invention, in the learning correction amount updating means, the parameter correlated to the intake air amount of the engine is the intake negative pressure of the engine, and the detected value of the intake negative pressure and the target value are set. The learning correction amount of the learning correction amount storage means is based on a value obtained by correcting the change amount of the control amount when the control amount for the auxiliary air control valve is changed in the direction of reducing the difference, based on the value corrected based on the engine rotation speed. Is configured to be updated.

According to this structure, when the effective opening area of the intake system changes (clogs), the suction negative pressure is reduced with respect to the target value during deceleration when the throttle valve is fully closed, depending on the engine speed at that time. Therefore, in order to obtain the deviation as the control amount for the auxiliary air control valve, the control amount is changed so that the suction negative pressure approaches the target value, and further, the change of the control amount at this time. The cost is corrected based on the engine rotation speed in order to be converted into a value equivalent to that during idle operation, and the learning correction amount is updated based on the correction result.

According to another aspect of the present invention, in the learning correction amount updating means, the parameter correlated with the intake air amount of the engine is the cylinder internal pressure of the engine, and the difference between the detected value of the cylinder internal pressure and the target value is calculated. The learning correction amount of the learning correction amount storage means is updated based on a value obtained by correcting the change amount of the control amount when the control amount for the auxiliary air control valve is changed in the direction of decreasing based on the engine rotation speed. It was configured to do.

According to this structure, when the effective opening area of the intake system changes (clogs), the cylinder pressure is decelerated with respect to the target value during deceleration of the throttle valve fully depending on the engine speed at that time. Since there is a deviation, in order to obtain the deviation as the control amount for the auxiliary air control valve, the control amount is changed so that the in-cylinder pressure approaches the target value, and the change amount of the control amount at this time is changed. Then, correction is performed based on the engine rotation speed in order to convert the value to a value equivalent to that during idle operation, and the learning correction amount is updated based on the correction result. In order to avoid the learning accuracy from being deteriorated due to the influence of variations in combustion, it is preferable to sample the in-cylinder pressure before ignition during the compression stroke or sample the in-cylinder pressure during deceleration fuel cut.

[0015]

Embodiments of the present invention will be described below. FIG. 2 is a system configuration diagram of the engine in the first embodiment. In FIG. 2, an intake passage 2 of the engine 1 is provided with a throttle valve 3, but an auxiliary air passage 4 that bypasses the throttle valve 3 is provided.
An electromagnetic auxiliary air control valve 5 is interposed in the auxiliary air passage 4.

The auxiliary air control valve 5 is driven by a duty signal that changes the ON time ratio (duty) within a fixed cycle, and the opening increases as the duty increases and decreases as the duty decreases. Therefore, the duty (%) here corresponds to the control amount. Also,
The intake passage 2 is provided with an electromagnetic fuel injection valve 6 for each cylinder to supply fuel.

The control unit 7 for controlling the operation of the auxiliary air control valve 5 and the fuel injection valve 6 has various sensors.
A signal is being input from the switch. Specifically, a crank angle sensor 8 that outputs a signal for each predetermined crank angle of the engine is provided, whereby the crank angle can be detected and the engine rotation speed N can be calculated.

Further, the opening TV of the air flow meter 9 and the throttle valve 3 for detecting the intake air flow rate Q in the intake passage 2.
A throttle sensor 10 for detecting O and a water temperature sensor 11 for detecting a cooling water temperature Tw are provided. In addition, although not shown, signals such as an engine key switch, a vehicle speed sensor, an air conditioner switch, a neutral switch, a load switch for detecting an electric load, and a radiator fan switch are input to the control unit 7.

Here, the microcomputer in the control unit 7 controls the control amount (duty) to the auxiliary air control valve 5 in accordance with the routines shown in FIGS. . Further, the basic fuel injection amount Tp = K · Q / N (K is a constant) is calculated from the intake air flow rate Q and the engine rotation speed N, and various corrections are made to this to obtain a final fuel injection amount Ti = Tp
× COEF + Ts (COEF is various correction coefficients including air-fuel ratio feedback correction coefficient, Ts is a battery voltage correction amount) is set, and a drive pulse signal having a pulse width corresponding to Ti is injected at a predetermined timing synchronized with the engine rotation. Output to the valve 6 for fuel injection.

The duty control routine of FIG. 3 will be described. This routine is executed every predetermined time. In step 1 (denoted as S1 in the figure. The same applies hereinafter), the basic control amount (basic duty) ISCT is referred to by referring to the table based on the cooling water temperature Tw detected by the water temperature sensor 11.
Set W.

In step 2, the feedback correction amount ISCI set by the feedback correction amount setting routine of FIG. 4 described later is read. In step 3, the learning correction amount ISCTAS stored in the rewritable RAM as the learning correction amount storage means is read. The learning correction amount ISCTAS corresponds to the amount of change in the amount of leaked air when the throttle valve 3 is fully closed (clogging amount). Incidentally, R
For AM, learning correction amount ISCTA even after key OFF
A backup power supply circuit is used to store and hold S.

In step 4, the basic control amount ISSTW, the feedback correction amount ISCI and the learning correction amount ISCTAS are added to obtain the control amount (duty) as shown in the following equation.
Calculate ISCON. This part corresponds to the control amount calculation means. ISCON = ISCTW + ISCI + ISCTAS In step 5, the duty signal corresponding to the control amount (duty) ISCON is output to open / close the auxiliary air control valve 5. This portion corresponds to the auxiliary air control valve drive means.

The feedback correction amount setting routine of FIG. 4 will be described. This routine corresponds to the feedback correction amount setting means and is executed every predetermined time. Steps
In 11, the idle speed feedback control condition (I
(SC condition) is determined. Here, the ISC condition is, for example, when the throttle valve 3 is fully closed (TVO = 0), the vehicle speed VSP is less than or equal to a predetermined value, and the engine speed N is within a predetermined range during idle operation. .

If it is the ISC condition, the process proceeds to step 12, but if it is not the ISC condition, this routine is terminated (at this time, the feedback correction amount ISCI is clamped to the previous value). In step 12, the crank angle sensor 8
The actual engine rotation speed (idle rotation speed) N calculated based on the signal from is read.

In step 13, the target idle rotation speed Ns is set by referring to the table based on the cooling water temperature Tw. In step 14, the actual idle rotation speed N is compared with the target idle rotation speed Ns. If N <Ns, the feedback correction amount ISCI is increased in step 15 by a predetermined integral amount ΔI. On the contrary, if N> Ns, the feedback correction amount ISCI is decreased by a predetermined integral amount ΔI in step 16.

The learning routine of FIG. 5 will be described. This routine is executed every predetermined time or every predetermined rotation. In step 21, it is determined whether or not the learning condition is based on the state of the external load. The learning condition by the external load is, for example, OFF of the air conditioner, N range, and no electric load.

If the learning condition is due to the external load, the routine proceeds to step 22, where it is judged whether or not it is a predetermined idle learning condition. The predetermined idle learning condition referred to here is, for example, during idle operation and during feedback control of idle rotation speed. Further, in order to learn in a stable state, a predetermined time has elapsed after the start, the water temperature Tw is within a predetermined range, the battery voltage is within a predetermined range, and the vehicle speed VSP =
It is even more preferable to set 0 as a condition that the air-fuel ratio feedback control is being performed.

In the case of the predetermined idle learning condition, the routine proceeds to step 23, where normal learning control is executed. In particular,
For example, the average value of the feedback correction amount ISCI is obtained, and the weighted average value of the feedback correction amount ISCTAS and the learning correction amount ISCTAS is used as a new learning correction amount ISCTAS to rewrite the stored data in the RAM. On the other hand, if it is determined in step 22 that the predetermined idle learning condition is not satisfied, the process proceeds to step 24, and it is determined whether or not the predetermined deceleration learning condition is satisfied.
This step 24 corresponds to deceleration detecting means.

The predetermined deceleration learning condition means that the throttle valve 3 is fully closed and the deceleration operation condition is in a high rotation range outside the ISC condition. If it is the deceleration learning condition, the process proceeds to steps 25 to 29 to update the learning correction amount ISCTAS. However, if it is not the deceleration learning condition, the learning correction amount ISCTAS is not updated and this routine is directly executed. To end.

Therefore, in addition to the normal learning in the step 23, the learning at the time of deceleration in the steps 25 to 29 is performed, and the learning is performed as compared with the case where the learning is performed only under the learning condition in the step 23. The frequency can be improved. The steps 25 to 29 correspond to learning correction amount updating means. In step 25, the intake air flow rate Q detected by the air flow meter 9 is read.

In step 26, the engine speed N is preset.
A target intake air flow rate Qa corresponding to the current rotational speed N is set by referring to a table in which the target intake air flow rate Qs is stored. In step 27, the deviation ΔQ between the measured value of the intake air flow rate Q and the target value Qs is calculated.

In step 28, the table corresponding to the deviation ΔQ is referred to find the duty corresponding to the deviation ΔQ. Then, at step 29, the learning correction amount ISCTA is set as the control amount corresponding to the change amount of the leak air amount when the throttle valve is fully closed, with the duty obtained at step 28.
Let S be updated. Such an update may include, for example, steps
The weighted average value of the duty calculated in 28 and the learning correction amount ISCTAS stored in the RAM is set as a new learning correction amount ISCTAS, and the data stored in the RAM is rewritten.

Next, a second embodiment will be described. FIG.
It is a system diagram of an engine in the second embodiment,
A negative pressure sensor 12 for detecting an intake negative pressure of the engine is added to the system configuration of FIG.
Then, in the second embodiment, the duty control routine of FIG. 3 and the feedback correction amount setting routine of FIG. 4 are executed in the same manner as in the first embodiment, while the learning routine of FIG. 5 is replaced. The learning routine shown in FIG. 7 is executed.

In FIG. 7, the steps 31 to 34 are the same as the steps 21 to 24 in FIG. 5, so the description thereof will be omitted. Steps 35 and subsequent steps showing the state of learning during deceleration will be omitted. explain. In step 35, the suction negative pressure PB detected by the negative pressure sensor 12 is read. Steps
In 36, the target suction negative pressure PBs is set by referring to the table based on the engine rotation speed N.

In step 37, the actual suction negative pressure PB is
Is approached to the target value PBs, in other words, the feedback correction amount ISCI is integratedly controlled in a direction to reduce the difference between the actual suction negative pressure PB and the target value PBs. At step 38, the feedback correction amount ISC obtained as a result of the control at step 37 is obtained.
The change amount ΔISCI of I is corrected based on the engine rotation speed at that time and converted into a duty equivalent to that during idle operation. This is because the influence of the change in the amount of leak air when the throttle valve is fully closed on the suction negative pressure depends on the rotation, and the duty required to obtain the target suction negative pressure at different rotation speeds is The duty is converted to the required duty at the target idle rotation speed.

In step 39, the learning correction amount ISCTAS is updated with the correction request duty at the target idle rotation speed obtained in step 38 as a control amount corresponding to the change amount of the leak air amount when the throttle valve is fully closed. To perform.
FIG. 8 is a system diagram of the engine according to the third embodiment, and has a configuration in which an in-cylinder pressure sensor 13 that detects an in-cylinder pressure P of the engine is added to the system configuration of FIG.

In the third embodiment, the duty control routine of FIG. 3 and the feedback correction amount setting routine of FIG. 4 are executed in the same manner as in the first embodiment, while the learning routine of FIG. 5 is executed. Instead of this, the learning routine shown in FIG. 9 is executed. In FIG. 9, steps 41 to 44
Since each step is completely the same as the steps 21 to 24 in FIG. 5, the description thereof will be omitted, and step 45 and subsequent steps showing the learning state during deceleration will be described.

In step 45, the in-cylinder pressure P detected by the in-cylinder pressure sensor 13 is read. In order to prevent the learning accuracy from decreasing due to the influence of combustion variations,
At 45, it is preferable to sample the in-cylinder pressure before ignition during the compression stroke or sample the in-cylinder pressure during deceleration fuel cut. In step 46, the target cylinder pressure Ps is set by referring to the table based on the engine speed N.

In step 47, the feedback correction amount ISCI is integratedly controlled in a direction in which the actual in-cylinder pressure P approaches the target value Ps. In step 48, the variation allowance ΔISCI of the feedback correction amount ISCI obtained as a result of the control in step 47 is corrected based on the engine rotation speed at that time, and converted into a duty equivalent to that during idle operation. This is because the influence of the change in the amount of leak air when the throttle valve is fully closed on the in-cylinder pressure depends on the rotation, and the duty required to obtain the target in-cylinder pressure at different rotational speeds is set to the target idle The duty is converted to the required duty at the rotation speed.

In step 49, the correction required duty at the target idle speed obtained in step 48 is updated as the control amount corresponding to the change in the amount of leaking air when the throttle valve is fully closed, and the learning correction amount ISCTAS is updated. To perform.

[0041]

As described above, according to the first aspect of the present invention, if there is a change in the leak air amount when the throttle valve is fully closed, the intake air flow rate during deceleration operation with the throttle valve fully closed, The change in the leaked air amount is learned by utilizing the change in the parameters related to the intake air amount such as the intake negative pressure and the in-cylinder pressure. Instead, learning can be performed even during deceleration, and the learning frequency can be improved.

According to the second aspect of the invention, there is an effect that the variation of the leaked air amount can be learned based on the fact that the deviation between the intake air flow rate during deceleration and the target value corresponds to the clogging amount. is there. According to the invention described in claim 3,
By correcting the variation allowance when the control amount is controlled so that the suction negative pressure during deceleration approaches the target value with the rotation speed, the correction required control amount during idle operation can be estimated, and thus the leakage air amount change There is an effect that the minutes can be learned.

According to the fourth aspect of the present invention, by correcting the change margin when the control amount is controlled so that the in-cylinder pressure during deceleration approaches the target value by the rotational speed, the correction request control amount during idle operation is obtained. Therefore, there is an effect that it is possible to learn the variation of the leaked air amount.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram showing the invention according to claim 1.

FIG. 2 is a system configuration diagram of an engine according to the first embodiment.

FIG. 3 is a flowchart of a duty control routine common to the first to third embodiments.

FIG. 4 is a flowchart of a feedback correction amount setting routine common to the first to third embodiments.

FIG. 5 is a flowchart of a learning routine according to the first embodiment.

FIG. 6 is a system configuration diagram of an engine according to a second embodiment.

FIG. 7 is a flowchart of a learning routine according to the second embodiment.

FIG. 8 is a system configuration diagram of an engine according to a third embodiment.

FIG. 9 is a flowchart of a learning routine according to the third embodiment.

[Explanation of symbols]

 1 engine 2 intake passage 3 throttle valve 4 auxiliary air passage 5 auxiliary air control valve 6 fuel injection valve 7 control unit 8 crank angle sensor 9 air flow meter 10 throttle sensor 11 water temperature sensor 12 negative pressure sensor 13 cylinder pressure sensor

Claims (4)

[Claims] 1. In an engine having an auxiliary air control valve in an auxiliary air passage that bypasses a throttle valve of an intake passage, an actual idle rotation speed is compared with a target idle rotation speed during idle operation, and the comparison is made according to the comparison result. Feedback correction amount setting means for setting a feedback correction amount, rewritable learning correction amount storage means for storing a learning correction amount corresponding to a change amount of the leak air amount when the throttle valve is fully closed, and at least the feedback correction amount. Control amount calculating means for calculating a control amount for the auxiliary air control valve based on the learning correction amount; and auxiliary air control valve driving means for driving the auxiliary air control valve to open and close by a signal corresponding to the control amount. , Deceleration detecting means for detecting a predetermined deceleration operating state when the throttle valve is fully closed, and the deceleration operating state by the deceleration detecting means Learning correction amount updating means for updating the learning correction amount in the learning correction amount storage means based on the difference between the detected value of the parameter correlated with the intake air amount of the engine and the target value of the parameter when detected. And an idle speed learning control device for an engine, which includes: 2. The learning correction amount updating means, wherein a parameter correlated with an intake air amount of the engine is an intake air flow rate of the engine, and a difference between a detected value of the intake air flow rate and a target value is calculated as the auxiliary air flow rate. 2. The control amount for the control valve is converted, and the learning correction amount in the learning correction amount storage means is updated based on the converted control amount.
An idle speed learning control device for the engine described. 3. The learning correction amount updating means, wherein the parameter correlated with the intake air amount of the engine is the intake negative pressure of the engine, and the difference between the detected value of the intake negative pressure and the target value is reduced. The learning correction amount of the learning correction amount storage means is updated based on a value obtained by correcting the variation amount of the control amount when the control amount for the auxiliary air control valve is changed based on the engine rotation speed. Claim 1
An idle speed learning control device for the engine described. 4. The learning correction amount updating means, wherein a parameter correlated with an intake air amount of the engine is an in-cylinder pressure of the engine, and the auxiliary is used in a direction of reducing a difference between a detected value of the in-cylinder pressure and a target value. The learning correction amount of the learning correction amount storage means is updated based on a value obtained by correcting the change amount of the control amount when the control amount for the air control valve is changed based on the engine rotation speed. The engine idle speed learning control device according to claim 1.