JPH05332183A - Idle speed control device for internal combustion engine - Google Patents

Abstract

(57) [Summary] [Object] The present invention prevents an idle speed following error after a low temperature start of an internal combustion engine, and prevents hunting of the engine speed and engine stall to stabilize the internal combustion engine. The purpose is to let. Therefore, the first non-energization time of the throttle motor is set and the second non-energization time larger than the first non-energization time is set.
The first and second energization time maps for setting the non-energization time and determining the energization time of the throttle motor are provided, and when the difference between the target engine speed and the actual engine speed is greater than or equal to the predetermined engine speed, the first engine speed is set. When the difference between the target engine speed and the actual engine speed is less than the predetermined engine speed while operating the throttle motor based on the non-energization time and the first energization time map, the second non-energization time and the second energization time map There is provided a control means for controlling the throttle motor so as to operate.

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 device for an internal combustion engine, and more particularly to an idle speed control device for an internal combustion engine which can stabilize an idle operating state after a cold start.

[0002]

2. Description of the Related Art In an intake system for introducing intake air into an internal combustion engine, as shown in FIG. 5, the intake throttle valve 204 is forcibly opened / closed during idle operation of the internal combustion engine (not shown) to control the throttle opening. A throttle motor (D which is a step motor driven by energization / de-energization to be changed)
C-motor) 212 having idle speed control device 20
Some are equipped with 2. In the idle speed control device 202, the throttle opening is adjusted by the expansion and contraction of the plunger of the throttle motor 212 during idle operation. The movement of the throttle motor 212 is controlled by the control means (ECU) 216.

Further, an idle switch 214 which is turned on and off is provided on the tip end side of the throttle motor 212 so as to detect the idle operation of the internal combustion engine. Furthermore,
The throttle opening during idling is measured by the throttle opening sensor 21 provided on the opposite side of the throttle lever 208.
8 to the control means 216. The throttle motor 212 is controlled only when the idle switch 214 is on.

As shown in FIG. 6, the control of the throttle motor 212 is performed by controlling the target engine speed according to the state of the internal combustion engine at that time (the primary table TKNEI based on the cooling water temperature).
SC) and the difference ΔNE between the idle target engine speed and the actual engine speed, as shown in FIG. 7, (TIDCMNE).

As a condition for prohibiting energization of the throttle motor 212, for example, once, the throttle motor 21
After energizing No. 2, the energization is not performed for 100 ms (non-energizing time KTOFNE) thereafter.

Further, such an idle speed control device is disclosed in, for example, Japanese Patent Application Laid-Open No. 56-20730. In the device described in this publication, at least one of the pulse width and drive voltage, which is the basis of DC motor drive, is set independently for forward rotation and reverse rotation of the DC motor, and D
The idle speed of the engine is corrected and controlled toward the target speed without being affected by the drive characteristics of the C motor and the acceleration / deceleration characteristics of the engine.

[0007]

Conventionally, however, the non-energization time of the throttle motor has to take a small number when importance is attached to the followability of the idle speed control, and the target engine speed and the actual engine speed. When there is a big difference between
Overshoot and undershoot of the throttle motor movement are inevitable. For this reason, there is a problem in that hunting of the engine speed occurs and engine stall occurs, and the state of the internal combustion engine tends to become unstable after the cold start.

If the above-mentioned energization OFF time is set to a large value, there is a problem in the followability of idle speed control. That is,
Even if there is a large difference between the target engine speed and the actual engine speed, it does not easily converge to the target speed. Also, if the setting of the energization off time is small, the blank time between energization and the next energization is short, so that it is not possible to suppress the overshoot when energizing the throttle motor, which causes hunting of the engine speed. ..

[0009]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention uses an energization / de-energization to open / close the intake throttle valve to change the throttle opening during idle operation of the internal combustion engine. In an idle speed control device for an internal combustion engine having a driven throttle motor, a first non-energization time of the throttle motor is set, and a second non-energization time which is larger than the first non-energization time is set. First and second energization time maps that determine the energization time of the throttle motor are provided, and when the difference between the target engine speed and the actual engine speed is equal to or greater than a predetermined engine speed, the first de-energization time and the first energization time are set. When the throttle motor is operated according to the time map and the difference between the target engine speed and the actual engine speed is less than the predetermined engine speed, By the non-energized time and a second energization time map, characterized in that a control means for controlling to operate the throttle motor.

[0010]

According to the structure of the present invention, the control means sets the first non-energization time and the first energization time map when the difference between the target engine speed and the actual engine speed is not less than the predetermined engine speed. The throttle motor is operated according to the above, and when the difference between the target engine speed and the actual engine speed is less than the predetermined engine speed, control is performed to operate the throttle motor based on the second non-energization time and the second energization time map. However, by controlling the movement of the throttle motor and operating the intake throttle valve, it is possible to avoid mistakes in tracking the engine speed after a low temperature start of the internal combustion engine, prevent engine speed hunting, engine stall, etc. Is stabilizing.

[0011]

Embodiments of the present invention will now be described in detail and specifically with reference to the drawings. 1 to 4 show an embodiment of the present invention. In FIG. 2, 2 is an idle speed control device for an internal combustion engine (not shown), and 4 is an intake throttle valve that controls the amount of intake air to the internal combustion engine 2. The intake throttle valve 4 is held by a throttle valve shaft 6.

A semi-circular throttle lever 8 is connected to one end of the intake throttle valve 4. An accelerator wire 10 connected to an accelerator pedal (not shown) is connected to one end of the throttle lever 8.

At the other end of the throttle lever 8, a throttle motor 12 composed of a step motor (DC motor) is provided.
Is provided. The throttle motor 12 is equipped with an idle switch 14 which comes into contact with the other end of the throttle lever 8 on the tip side.

The idle switch 14 is provided for the internal combustion engine 2
The throttle motor 12 turns on during idle operation of the
Control is performed, and it is turned off at times other than idle operation.

A control means 16 (ECU) is connected to the throttle motor 12. Further, a throttle opening sensor 18 provided on the other end side of the throttle valve shaft 6 and an engine speed sensor 20 for detecting the engine speed are connected to the control means 16. A battery 22 is connected to the throttle opening sensor 18.

Further, the first non-energization time (KTOFNE1) of the throttle motor 12 is set, and the second non-energization time (KTOFNE2) which is larger than the first non-energization time (KTOFNE1) is set. First and second energization time maps (TTDCMN1, TTDCNE2) that determine the energization times of 12 are provided, and when the difference ΔNE between the target engine speed and the actual engine speed is equal to or greater than the predetermined engine speed (KTOFDNE). , The first non-energization time (KTOFNE1) and the first energization time map (TTDCNE1) to operate the throttle motor 12, and the difference ΔNE between the target engine speed and the actual engine speed is the predetermined engine speed (KTO).
When it is less than FDNE, the second non-energization time (KTOFNE)
2) and the second energization time map (TTDCNE2) are provided to control means 16 for controlling the throttle motor 12 to operate.

More specifically, the program of the control means 16 includes a first non-energization time (KTOFNE1), a second non-energization time (KTOFNE2), and a predetermined engine speed (KT).
OFDNE) is set, and the first and second
Energization time map (TTDCNE1, TTDCMNE
2) is incorporated.

In this embodiment, the first non-energization time (KTOFNE1) is set to, for example, 200 ms,
The second non-energization time (KTOFNE2) is, for example, 1000
is set to ms, and the predetermined engine speed (KTOFDN
E) is set to 80 rpm, for example.

The control means 16 controls the first non-operation when the difference ΔNE between the target engine speed and the actual engine speed input from the engine speed sensor 20 is equal to or higher than a predetermined engine speed (KTOFDNE). Energization time (KTO
FNE1) and first energization time map (TTDCMN1)
The throttle motor is operated by and when the difference ΔNE between the target engine speed and the actual engine speed input from the engine speed sensor 20 is less than the predetermined engine speed (KTOFDNE), the second de-energization. Time (KTOFNE2) and second energization time map (TTDC
The MNE 2) controls the throttle motor 12 to operate.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG.

When the program of the control means 16 is started (step 102), first the engine speed and the cooling water temperature are input (step 104), and it is judged whether or not the internal combustion engine has been started (step 106). ).

If YES at step 206,
It is determined whether the idle switch 14 is on (step 108).

Step 106 and Step 10
If NO in step 8, the process returns to step 104.

If YES at step 108,
The difference ΔNE between the idle speed and the actual engine speed is input (step 110), and the difference ΔNE between the idle speed and the actual engine speed is equal to or greater than the predetermined engine speed (KTOFDNE). Whether or not the difference ΔNE between the idle speed and the actual engine speed is equal to the predetermined engine speed (KTOFDN
E) or above, the first energization time map (TTDCM)
After the throttle motor 12 is energized according to NE1), the throttle motor 12 is deactivated for the first non-energization time (KTOFNE1) (step 114), and it is determined whether the idle switch is in the ON state (step 116).

Further, in the judgment (step 112), the difference ΔNE between the idle speed and the actual engine speed is ΔNE.
Is less than the predetermined engine speed (KTOFDNE), the second non-energization time (time larger than the first non-energization time (KTOFNE1) after energizing the throttle motor 12 according to the second energization time map (TTDCNE2) ( Only KTOFNE2) is halted (step 118), and then the determination (step 116) is performed.

If the judgment (step 116) is YES, the process returns to the step 110, and if the judgment (step 116) is NO, the program is ended (step 118).

As a result, the non-energization time can be set to a large value when the engine is cold, and the non-energization time can be set to a small value when the temperature is high, so that the idle speed control can be followed when the internal combustion engine is unstable. It is possible to prevent mistakes, and to prevent hunting of engine speed and engine stall in feedback control to the target speed.
The operation of the internal combustion engine can be stabilized, which is practically advantageous.

[0028]

As is apparent from the above detailed description, according to the present invention, the first non-energization time of the throttle motor is set and the second non-energization time larger than the first non-energization time is set. First and second energization time maps that determine the energization time of the throttle motor are provided, and when the difference between the target engine speed and the actual engine speed is equal to or greater than a predetermined engine speed, the first de-energization time and the first energization time are set. The throttle motor is operated according to the time map, and the throttle motor is operated according to the second non-energization time and the second energization time map when the difference between the target engine speed and the actual engine speed is less than the predetermined engine speed. Since the control means for controlling the engine speed is provided, it is possible to prevent the idle speed following error after the cold start of the internal combustion engine and to prevent hunting of the engine speed. Prevents engine stall or the like, and obtained to stabilize the internal combustion engine, it is practically advantageous.

[Brief description of drawings]

FIG. 1 is a flowchart of idle speed control in a first embodiment.

FIG. 2 is a system configuration diagram of an idle speed control device.

FIG. 3 is a first energization time map.

FIG. 4 is a second energization time map.

FIG. 5 is a system configuration diagram of a conventional idle speed control device.

FIG. 6 is a map of an idle target engine speed according to a cooling water temperature.

FIG. 7 is a map of a difference in engine speed.

[Explanation of symbols]

 2 Idle speed control device 4 Intake throttle valve 8 Throttle lever 10 Accelerator wire 12 Throttle motor 14 Idle switch 16 Control means 18 Throttle opening sensor 20 Engine speed sensor 22 Battery

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[Procedure amendment]

[Submission date] July 16, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction content]

If the judgment (step 116) is YES, the process returns to step 110, and if the judgment (step 116) is NO, the program is ended (step 120 ).

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

[Figure 6]

[Figure 7]

[Figure 1]

Claims (1)

[Claims] Claim: What is claimed is: 1. When the internal combustion engine is idle, the intake throttle valve is opened and closed to change the throttle opening.
In an idle speed control device for an internal combustion engine having a throttle motor driven by non-energization, a first non-energization time of the throttle motor is set, and a second non-energization time larger than the first non-energization time is set. However, the first and second energization time maps for determining the energization time of the throttle motor are provided, and when the difference between the target engine speed and the actual engine speed is equal to or greater than the predetermined engine speed, the first engine speed is set to the first engine speed.
When the difference between the target engine speed and the actual engine speed is less than the predetermined engine speed while operating the throttle motor based on the non-energization time and the first energization time map, the second non-energization time and the second energization time map An idle speed control device for an internal combustion engine, characterized in that a control means for controlling the throttle motor to operate by the above is provided.