JPH1193736A - Idling rotation learning control device for electronically controlled throttle valve type internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely correct a reduced amount of an opening area due to fauling in an intake system or the like in a system for providing a target idling speed by controlling a throttle valve opening. SOLUTION: When a learning condition is satisfied (S11), requirement for homogeneous charge combustion is generated (S13). A mean value QFBIAV of feedback correction air volume QFBI integral-controlled to find a target idling speed is computed at first (S15, S16). Then the weighted mean value for an air volume learning correction value ISCLRC and the mean value QFBIAV is found to update the ISCLRC (S17), and the air volume learning correction value ISCLRC (liter/min.) is converted into an opening area learning value ATASLN (cm<2> ) (S21). The opening area learning value ATASLN is added to the target opening area obtained by converting a target air volume, and the addition-corrected target opening area is converted into a throttle opening to control a throttle valve opening.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle rotation learning control system for an electronically controlled throttle type internal combustion engine.
In an internal combustion engine provided with an electronically controlled throttle system for electronically controlling the opening of a throttle valve, the present invention relates to an apparatus for controlling idle speed by controlling the opening of the throttle valve.

[0002]

2. Description of the Related Art Conventionally, while a throttle valve is configured to be opened and closed by an actuator such as a motor, a target air amount is set based on an accelerator operation amount and the like.
There has been known an electronically controlled throttle system configured to electronically control the opening of a throttle valve to an opening at which the target air amount is obtained.

[0003] In addition, during idle operation of the engine, the intake air amount of the engine is feedback-controlled so that the engine speed approaches the target idle speed. On the other hand, when a predetermined learning condition is satisfied, the feedback correction is performed. There is known a configuration in which the amount of air is learned as a decrease in the opening area over time due to contamination or clogging of the intake system, and the amount of intake air is corrected based on the learned value.

[0004]

In an engine equipped with the electronically controlled throttle system for controlling the throttle valve opening by setting the target air amount as described above, the opening of the throttle valve is controlled. May be configured to obtain the target idle rotation speed, but in such a configuration, the learning value is generally learned as an air amount (liter / min).

However, the conditions for performing the learning (for example, idling, warming up, electric load OFF, and neutral)
In a state in which an electric load is applied to the air flow, even if the learning value as the air flow rate is reflected, the suction negative pressure is different from that at the time of learning, and the air corresponding to the decrease in the opening area is changed. There was a problem that the amount was not corrected and the target idle rotation speed could not be stably obtained.

That is, the learning value indicates how much the air amount decreases under the learning condition due to the decrease in the opening area due to dirt or clogging. Since the change in the air amount due to the change in the area is different, even if the learning value is reflected when the suction negative pressure differs from the learning condition, a correction was made to match the decrease in the air amount due to the change in the opening area. It does not become.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and in an internal combustion engine having an electronically controlled throttle system and obtaining a target idle rotation speed by electronic control of a throttle valve opening, a suction load different from that during learning. It is an object of the present invention to provide an idle rotation learning control device capable of correcting an air amount corresponding to dirt or clogging of an intake system by a learning value even under pressure.

[0008]

According to a first aspect of the present invention, there is provided an idle rotation learning control device for setting a target air amount according to operating conditions of an engine and for setting the target air amount to a target opening of a throttle valve. FIG. 1 shows an electronically controlled throttle type internal combustion engine provided with an electronically controlled throttle system for opening and closing a throttle valve with an actuator so as to convert the area into the target opening area.

In FIG. 1, the idle speed feedback control means performs feedback control of the target air amount so that the engine speed approaches the target idle speed during an idle operation of the engine. When a predetermined learning condition is satisfied, the idle rotation learning means converts the amount of air corrected by the idle rotation feedback control means into an opening area of the throttle valve, and learns the opening area as an idle rotation learning value. I do.

The learning correction means corrects and sets the target opening area based on the idle rotation learning value as the opening area learned by the idle rotation learning means. According to this configuration, the target air amount is feedback-corrected in order to obtain the target idle rotation speed, and the amount of air corrected by the feedback correction is used to correct dirt and clogging of the intake system when a predetermined learning condition is satisfied. Learning is performed as the amount of decrease in the opening area due to the above. The air amount (liter / min) is converted into the opening area (cm ² ), and a learning value as the opening area is set. Then, the target opening area obtained by converting the target air amount is corrected and set based on the learning value learned as the opening area.

According to a second aspect of the present invention, the combustion system of the internal combustion engine is switched between stratified combustion by injection in a compression stroke and homogeneous combustion by injection in an intake stroke. The means is configured to prohibit the stratified combustion and perform the learning in the homogeneous combustion state when a predetermined learning condition is satisfied. According to this configuration, when performing learning, if stratified combustion (combustion at an ultra-lean air-fuel ratio) is being performed, switching to homogeneous combustion (combustion at a richer air-fuel ratio than during stratified combustion) is performed, and then learning is performed. As a result, learning is performed under the condition that the intake air amount of the engine is small and the influence of dirt or clogging is more likely to appear.

According to the third aspect of the present invention, the idle rotation learning means performs the learning once at a time while the ignition switch is ON. According to such a configuration,
If learning is performed at least once after the ignition switch is turned on, then learning with prohibition of stratified combustion is not performed even if the learning conditions are satisfied.

[0013]

According to the first aspect of the present invention, the correction of the target air amount when the target idle air speed is obtained by feedback-correcting the target air amount of the electronically controlled throttle system is determined by the dirt and clogging of the intake system. When learning as a minute, it is converted to the opening area of the throttle valve. Therefore, even if the condition of the suction negative pressure changes, the air amount corresponding to the decrease in the opening area due to the dirt and clogging is corrected. There is an effect that can be made.

According to the second aspect of the present invention, the learning of the decrease in the opening area of the intake system due to dirt or clogging is performed by switching from the stratified combustion state to the homogeneous combustion state. Thus, the learning can be performed in a state in which the decrease in the amount of air due to the above is high in the ratio of the total amount of air, so that the learning can be performed with high accuracy.

According to the third aspect of the invention, there is an effect that the learning of switching from stratified combustion to homogeneous combustion is performed more frequently than necessary, thereby preventing deterioration in fuel consumption performance and exhaust characteristics.

[0016]

Embodiments of the present invention will be described below. FIG. 2 is a system configuration diagram of the internal combustion engine according to the embodiment. The internal combustion engine 1 shown in FIG. 2 includes a fuel injection valve 2 for directly injecting fuel into a cylinder for each cylinder, and also includes a fuel injection valve 2 for each cylinder. A direct-injection gasoline engine (direct-injection spark ignition engine) provided with a spark plug 4.

The fuel injection valve 2 is controlled for each cylinder in accordance with an injection pulse signal from a control unit 3 containing a microcomputer.
Each ignition plug 4 is provided with an ignition coil 5, and a power tra unit 6 turns on and off the power supply to the primary side of each ignition coil 5 in response to an ignition signal from the control unit 3. The ignition timing is controlled for each cylinder.

On the other hand, there is provided an electronically controlled throttle system for opening and closing the throttle valve 8 for measuring the intake air amount of the engine by a motor 13 controlled by the control unit 3. The control unit 3 receives detection signals from various sensors for controlling fuel injection, ignition timing, throttle opening, and the like.

The various sensors include an air flow meter 7 for detecting an intake air flow rate, a throttle sensor 9 for detecting an opening degree of a throttle valve 8, a crank angle sensor 10 for detecting a crank angle, and a water temperature sensor for detecting a coolant temperature. 1
1. Oxygen sensor that detects the average air-fuel ratio of the combustion mixture based on the oxygen concentration in the exhaust gas 12, Vehicle speed sensor that detects the vehicle speed
14, neutral switch 15 for detecting the neutral state of the transmission, electric load switch 16, accelerator opening sensor
17 and so on are provided.

Here, the control unit 3 comprises:
A plurality of target equivalence ratio maps in which a target equivalence ratio (target air-fuel ratio) and a combustion mode are set in advance in accordance with a target output torque and an engine speed are provided. The fuel injection amount and the injection timing of the fuel injection valve 2 are controlled by switching and referring to conditions such as acceleration, acceleration, and the like, determining the target equivalent ratio and requesting the combustion mode.

The combustion mode includes a homogeneous combustion mode in which fuel is injected in an intake stroke to perform homogeneous combustion, and a fuel-fuel mixture is injected in a compression stroke to form a rich air-fuel mixture in the vicinity of the ignition plug 4 to achieve a stratified lean operation. A stratified combustion mode for performing combustion is set, and in the homogeneous combustion mode, the target equivalent ratio is controlled to lean, stoichiometric (stoichiometric air-fuel ratio), or rich in accordance with the operation range,
In the stratified combustion mode, the control is further controlled to be leaner than in the homogeneous lean combustion.

The control unit 3 electronically controls the opening of the throttle valve 8 as shown in FIG. First, a target air amount (liter / min) is calculated based on the accelerator opening, the engine speed Ne, the target equivalent ratio, and the like (S1). The calculation of the target air amount includes the calculation of the reference target air amount and the setting of the final target air amount by correcting the reference target air amount.

The target air amount is converted into a throttle opening area (S2), and the opening area is converted into a target opening of the throttle valve 8 (S3). Then, the motor 13 is feedback-controlled so that the actual opening detected by the throttle sensor 9 matches the target opening.
The addition correction of the opening area learning value in FIG. 3 will be described later.

Further, during idle operation, the control unit 3 sets the feedback correction air amount QFBI (liter / min) by integral control so that the engine rotation speed approaches the target idle rotation speed. The target air amount (reference target air amount) is corrected. The function of the control unit 3 corresponds to an idle rotation feedback control unit.

Further, the opening area with respect to the opening degree decreases with time due to contamination of the throttle valve 8, and the amount of intake air obtained with respect to the opening degree is learned. The situation will be described with reference to FIG. In FIG. 4, first, it is determined whether a learning condition is satisfied (S11). The learning conditions are that the feedback control of the idling rotation is being performed, that the engine is in a warm-up / neutral state, and that no load such as an electric load or an air conditioner load is applied.

Here, even if it is determined that the learning condition is satisfied,
Next, when it is determined from the learning end flag that learning has already been performed, learning is not performed (S12). The learning end flag is set when learning is performed, and is reset when the ignition switch is turned ON → OFF. Therefore, during one trip (between ON and OFF of the ignition switch), the learning end flag is set. Is performed once, the learning is prohibited even if the learning condition is satisfied.

The change in the opening area with the passage of time does not change abruptly, and the learning value can be sufficiently followed by executing it once per trip. On the other hand, for example, the learning is performed every time the learning condition is satisfied. If the learning is performed a plurality of times during one trip, the learning is forcibly switched to the homogeneous combustion, which will be described later. Will only be aggravated. Therefore, in the present embodiment, learning is performed only once during one trip.

If it is determined that the learning condition is satisfied and the learning is not completed as described above, a homogeneous combustion request is generated (S13). Switch to. The target equivalence ratio is enriched by the switching of the combustion method, and the intake air amount (reference target air amount) of the engine corresponding to the target torque decreases and changes. You will be able to learn.

Since the engine becomes unstable immediately after switching to the homogeneous combustion, the process shifts to learning after waiting for a certain delay time (S14). In the learning, first, the feedback correction air amount QFBI is sampled at regular intervals (S15), and an average value QFBIAV of the sampled air amount QFBI is calculated (S16).

Then, the air amount learning correction value IS
The weighted average of CLRC and the average value QFBIAV is updated, and the weighted average value is updated and stored as a new air amount learning correction value ISCLRC (S17). However, the air amount learning correction value ISCLRC is limited to a predetermined maximum / minimum value (S18).

When the air amount learning correction value ISCLRC is updated, a learning end flag is set (S19),
Release the request for homogeneous combustion and allow stratified combustion (S2
0). The air amount learning correction value ISCLRC (liter / m
in) is an opening area learning value ATASL based on a coefficient for converting a flow rate into a throttle opening area under the learning conditions.
It is converted to N (cm ² ) (S21).

As shown in FIG. 3, the opening area learning value ATASLN is added to a target opening area obtained by converting a target air amount, and the addition corrected target opening area is converted into a throttle opening. To do it. The air amount learning correction value ISCLRC is a value corresponding to the decrease in the opening area when the learning condition is satisfied. However, when the suction negative pressure is different, the air amount corresponding to the decrease in the opening area changes. The air amount learning correction value IS
In the CLRC, the amount of decrease in the opening area is not corrected. On the other hand, the opening area learning value ATASL
Since N is a value that directly indicates the amount of decrease in the opening area, the target opening area is corrected by the opening area learning value ATASLN even when the suction negative pressure is different from that at the time of learning. Is corrected to compensate for the decrease in the amount of air due to the decrease in the air amount.

[Brief description of the drawings]

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

FIG. 2 is a system configuration diagram of an internal combustion engine in the embodiment.

FIG. 3 is a control block diagram showing a state of throttle opening control in the embodiment.

FIG. 4 is a control block diagram showing a state of idle learning control in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Fuel injection valve 3 Control unit 4 Spark plug 7 Air flow meter 8 Throttle valve 9 Throttle sensor 10 Crank angle sensor 11 Water temperature sensor 12 Oxygen sensor 13 Motor 14 Vehicle speed sensor 15 Neutral switch 16 Electric load switch 17 Accelerator opening sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02D 45/00 358 F02D 45/00 358H (72) Inventor Taiyo Yoshino 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd.

Claims (3)

[Claims] 1. A target air amount is set according to operating conditions of an engine, the target air amount is converted into a target opening area of a throttle valve, and the throttle valve is opened / closed by an actuator so as to have the target opening area. An electronically controlled throttle type internal combustion engine provided with an electronically controlled throttle system that performs feedback control of the target air amount so that the engine rotational speed approaches the target idle rotational speed during idle operation of the engine; When the learning condition is satisfied, an idle rotation learning unit that converts a correction air amount by the idle rotation feedback control unit into an opening area of the throttle valve and learns the opening area as an idle rotation learning value; The idle rotation learning value as the opening area learned by the idle rotation learning means is used. , The target opening area correction setting learning correction means and the comprise idle rotation learning control apparatus for electronically controlled throttle internal combustion engine characterized in that it is configured. 2. The combustion system of the internal combustion engine is switched between stratified combustion by injection in a compression stroke and homogeneous combustion by injection in an intake stroke. 2. The idle rotation learning control system for an electrically controlled throttle-type internal combustion engine according to claim 1, wherein when the condition is satisfied, the stratified combustion is prohibited and learning is performed in the homogeneous combustion state. 3. An idle rotation learning control system for an electronically controlled throttle-type internal combustion engine according to claim 2, wherein said idle rotation learning means performs learning once at a time when an ignition switch is ON.