JPH05272387A - Control of idle rotation speed - Google Patents

Abstract

PURPOSE:To prevent generation of engine stalling at high ground by controlling a flow control valve provided in a bypass passage based on a learned value corrected in accordance with a detected atmospheric pressure, and controlling an engine rotation speed in idling by regulating intake air quantity. CONSTITUTION:In a step 61 in an electronic controller 6, when an elapsed time (t) counted by a timer is not more than a control time alpha in open control, the step is shifted to a step 62, where an atmospheric pressure detected by a pressure sensor 16 is read, and the step is shifted to a step 63. Among correction values FDISC set in accordance with the atmospheric pressures, the correction value FDISC for the detected atmospheric pressure is searched, and the step is shifted to a step 64. The correction value obtained in the step 62 is added to a learned value learned at low ground, and a flow control valve 5 is controlled with a determined control value DISC in a step 65. In the case of moving to high ground with the learned value at the low ground unchanged, even when an idling condition occurs after climbing with a throttle valve 2 fully open, generation of engine stalling can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle speed control method mainly applied to an automobile engine.

[0002]

2. Description of the Related Art As a conventional idle speed control method of this type, for example, an engine idle speed control device disclosed in JP-A-63-154839 discloses a flow rate in a bypass passage bypassing a throttle valve. By providing a control valve and adjusting the intake air amount by controlling the opening of this flow control valve based on a control value, feedback control is performed so that the engine speed during idling converges to the target speed. Are known. It is also known that the control value is learned according to the state of the engine and stored as a learned value to control the opening of the flow control valve.

[0003]

By the way, in the above configuration, when the control value at the time of idling in the lowland is learned and stored as the learned value, and then the vehicle moves to the highland and becomes in the idling state, Open control is performed by adding a fixed value to the stored learning value, that is, the learning value in the lowland. However, because the atmospheric pressure is low in the highlands and the air is thin, the learning value in the lowlands is low, so if the flow control valve is opened using this, the required intake air amount in the highlands will be reduced. There was a case where the engine stalls without generating.

An object of the present invention is to eliminate such a problem.

[0005]

The present invention takes the following means in order to achieve such an object. That is, the idle speed control method according to the present invention is provided with a flow rate control valve in a bypass passage bypassing the throttle valve, and controls based on a learned value of a control value for controlling the opening degree of the flow rate control valve. It is an idle speed control method that controls the engine speed during idling to converge to the target speed by adjusting the intake air amount, and detects the atmospheric pressure, and a correction value according to the detected atmospheric pressure. The learning value is corrected according to, and the flow control valve is controlled based on the control value obtained by the correction.

[0006]

With this structure, the learned value of the control value for controlling the opening of the flow control valve is corrected based on the detected atmospheric pressure value. In other words, even if the learning value in the lowlands is used in the highlands, the learning value is corrected by the correction value according to the detected atmospheric pressure. Therefore, the flow control valve is apparently based on the learning value in the highlands. Will be controlled. Therefore, when the vehicle travels to the highland with the learning value at the time of idling in the lowland as it is, the engine stall does not occur even if the vehicle is idling after climbing the throttle valve with the throttle valve fully opened.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

An engine 1 schematically shown in FIG. 1 is used in an automobile and is equipped with a fuel injection device (not shown), and an intake system 3 in which a throttle valve 2 is installed bypasses the throttle valve 2. A bypass passage 4 is provided. The bypass passage 4 is provided with a flow rate control valve 5 for adjusting the intake air amount during idling. The flow rate control valve 5 is composed of an electromagnetic valve whose opening is controlled by a control signal a from an electronic control unit 6 described later. The opening degree is controlled by the ratio (duty ratio) of the opening time and the closing time.

The electronic control unit 6 is provided with a central processing unit 7, a storage unit 8, an input interface 9 and an output interface 10, and has a function of feedback-controlling the engine speed during idling to a target speed. It has a function of adjusting the amount of fuel injected from the fuel injection valve. The central processing unit 7 has a built-in timer for measuring the time during which the open control is executed. The input interface 9 has an engine rotation signal b from a crank angle sensor 11, a signal c from an idle switch 12, a signal d from a headlight switch 13, a signal e from a fan motor switch 14 for a radiator,
A signal f from the fan motor switch 15 for the heater,
The signal g and the like from the pressure sensor 16 are input respectively. Further, the output interface 10 outputs a control signal a to the flow control valve 5 and also outputs a signal to the fuel injection valve and the like.

The crank angle sensor 11 is for detecting the engine speed, and is provided in a distributor (not shown). The idle switch 12 is turned on when the throttle valve 3 is in the idling position, and is turned off when the throttle valve 3 is in the non-idling position.
It is an off switch, and is linked to the throttle shaft 2a. The headlight switch 13 is an on / off switch that is turned on when the headlight is turned on. The fan motor switch 14 is used when the fan fan motor for the radiator is driven, and the fan motor switch 15 for the heater is used for the heater. Is an on / off switch which is turned on when the fan motor of is driven. Further, the pressure sensor 16 is configured to output an electric signal g proportional to the detected pressure, that is, the atmospheric pressure.

The electronic control unit 6 contains a program as schematically shown in FIGS. First, the idle switch 12 when the engine 1 is idling
On the premise that the flow rate control valve 5 is controlled by the fully open duty ratio, the control value obtained by adding the correction value FDISC to the learning value DISCBSE of the control value is determined in step 51 and step 52. It is determined whether or not each condition of the open control controlled by the duty ratio is satisfied, and in step 51, the condition of the full open control (the current engine speed exceeds the predetermined speed in racing, etc.) is satisfied. If it is determined that there is a step 53
When it is determined in step 52 that the open control conditions (full open control is completed, engine water temperature is below the set value, warming up is not completed, etc.) are satisfied, Moves to step 54. Step 53
In step 54, the fully open control is executed, and in step 54, the open control is executed. If it is determined in step 52 that the condition is not satisfied, the process proceeds to step 55, in which feedback control is performed so that the target engine speed at idling is compared with the engine speed at that time so that the engine speed becomes the target engine speed. To execute.

The open control in step 54 is executed by the subroutine shown in FIG. First, in step 61, it is judged whether or not the elapsed time t measured by the timer of the electronic control unit 6 is the control time α or more of the open control, and if it is the control time α or more, the process returns to the main routine, and otherwise. If so, the process proceeds to step 62. In step 62, the atmospheric pressure is detected by the signal g from the pressure sensor 16 and is temporarily stored in the storage device 8, and the process proceeds to step 63. The method for detecting or reading the atmospheric pressure itself may be a method known in the art. In step 63, the correction value FDISC corresponding to the detected atmospheric pressure is searched from the correction values FDISC set on the one-dimensional map according to the atmospheric pressure, and the process proceeds to step 64. The correction value FDISC is set to 10 (%) with respect to the atmospheric pressure 760 (mmHg), for example, 560
The value obtained by interpolating between 40% and (mmHg) is used. In step 64, the control value DI is obtained by adding the correction value FDISC obtained in step 62 to the learning value DISCBSE _(L) learned in the lowland of the control value.
SC is calculated, and the process proceeds to step 65. Step 65
Then, the opening degree of the flow control valve 5 is controlled by the calculated control value DISC. The above steps 61 to 65 are repeatedly executed, and when the elapsed time t becomes equal to or more than the control time α in step 61, the process returns to the main routine.

In the above configuration, the control value DISC is learned in the idling state in the lowland to learn the learning value DI.
A case will be described in which SCBSE _(L) is obtained, then the throttle valve 2 is fully opened, the vehicle travels uphill, the vehicle is stopped at a high altitude, and the vehicle enters the idling state again.

In this case, first, the control proceeds to steps 51 and 52, and it is determined that the condition of the open control is satisfied, and the routine proceeds to step 54. Open control is performed in steps 61 to 6
5 is repeatedly executed, and when it is determined in step 61 that the elapsed time t measured by the timer is equal to or longer than the control time α, the process returns to step 51 again, and the operating state of the engine at that time is fully open control, open. It is determined whether the control or the feedback control corresponds, and each control is executed.

In the case of general conventional open control,
In the case of the above-mentioned driving situation, a fixed value different from the feedback value in the feedback control is set to the learning value DISCB.
Although it is added to SE _(L) to function like a dashpot, in the case of such a control method, the learning value DI
SCBSE _(L) is the learning value at high altitude DISCBSE ₍
Since it is not _H) , even if a constant is added, engine stall may occur before shifting to the feedback control.
This is because the learning value DISCBSE _(L) is low, and therefore, even if a constant is added, the control value DISC is not sufficient to supply the intake air amount in the highlands required to function as a dashpot. On the other hand, in this embodiment, the atmospheric pressure is detected (step 62), and the learning value DISCBSE is obtained from the correction value FDISC corresponding to the atmospheric pressure.
_{Since (L)} is corrected (step 64), it is equivalent to the apparent learning value DISCBSE _(L) being increased corresponding to the atmospheric pressure. Therefore, even in a high altitude where the air is thin, it is possible to determine the control value DISC that makes the intake air amount sufficient to function as a dashpot, and to cause an engine stall even in such an operating condition. There is no.

The present invention is not limited to the embodiment described above. For example, although the fuel injection type engine 1 has been described in the above embodiment, a carburetor type may be used. Also, the case where the control value DISC is calculated by using the correction value FDISC as a one-dimensional map has been described.
The ISC may be calculated by multiplying the detected atmospheric pressure by a coefficient and added to the learned value DISCBSE _(L) to obtain the control value DISC according to the atmospheric pressure.

In addition, the configuration of each part is not limited to the illustrated example, and various modifications can be made without departing from the spirit of the present invention.

[0018]

As described in detail above, according to the present invention, the learning value of the control value for controlling the opening degree of the flow control valve is corrected based on the detected atmospheric pressure value. It is possible to prevent the engine stall from occurring even if the vehicle moves to a high altitude with the learning value at the time as it is, even if the throttle valve is fully opened and the vehicle is idling after ascending the slope.

[Brief description of drawings]

FIG. 1 is a schematic overall configuration diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing a control procedure of the embodiment.

FIG. 3 is a flowchart showing a control procedure of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Throttle valve 4 ... Bypass passage 5 ... Flow control valve 6 ... Electronic control device 7 ... Central processing unit 8 ... Storage device 9 ... Input interface 10 ... Output interface

Claims (1)

[Claims] 1. A flow control valve is provided in a bypass passage that bypasses a throttle valve, and the intake air amount is adjusted by controlling based on a learned value of a control value for controlling the opening of the flow control valve. In the idle speed control method for controlling the engine speed during idling to converge to a target speed, the atmospheric pressure is detected, and the learned value is corrected by a correction value according to the detected atmospheric pressure, An idle speed control method characterized by controlling the flow control valve based on a control value obtained by the correction.