JPS63289239A - Idling speed control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent the sudden fall of an engine speed by correctively increasing a valve opening duty of a pulse signal to be applied to an idling control valve when a rate of decrease in the engine speed at idling of an engine is not less than a predetermined value. CONSTITUTION:An idling control valve A is provided in an auxiliary air passage bypassing a throttle valve of an internal combustion engine. A pulse signal having a valve opening duty according to an engine operational condition is output from idling speed control means B to the idling control valve A to control an opening of the valve A and maintain an idling speed at a predetermined value. Such a control device is provided with idling condition detecting means C and engine speed decreasing rate detecting means D. When a rate of decrease in the engine speed at idling of the engine is not less than a predetermined value, dash pot signal generating means E generates a dash pot signal for correctively increasing the valve opening duty of the pulse signal.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an idle speed control device for an internal combustion engine, and more particularly to dashpot control that prevents engine stalling during deceleration operation.

<Prior Art> In order to maintain the idle speed of the internal combustion engine at an optimum value and improve fuel efficiency, in recent years, as shown in FIG. An idle control valve 3 is interposed in the engine 2, and the opening degree of the idle control valve 3 is increased or decreased depending on the operating state of the engine to control the idle speed. In addition, the idle control valve 3
The control unit 4 determines the engine operating state based on various detection signals such as engine speed and engine cooling water temperature, and supplies the valve to the idle control valve 3 according to the operating state. Pulse signal valve opening duty (
This is done by changing the ON time ratio in the pulse period), and the engine speed in the idle operating range is controlled so as to reach the target idle speed. In addition, 5
6 is the engine body, 6 is an air flow meter, and 7 is an air cleaner.

On the other hand, in order to prevent the engine speed from suddenly decreasing due to the undershoot phenomenon during deceleration and causing the engine to stall, dashpot control is performed to control the idle control valve 3 to correct the increase or decrease of the intake air amount. (See Utility Model Application Publication No. 61-37442, etc.). In particular, in the case where the fuel supply is cut off at the beginning of deceleration, the engine speed drops significantly, so dashpot control is highly necessary. 7 <Problems to be Solved by the Invention> As shown in Fig. 5, the conventional dashpot control is designed to prevent the intake throttle valve 1 from fully closing during deceleration operation and the idle switch to turn on, and at the same time to turn on the predetermined dash. A pot duty was added, and thereafter the dash pot duty was gradually decreased linearly at every predetermined engine speed.

However, in this dashpot control method, although it is possible to prevent a sudden drop in rotation speed during normal deceleration operation by adding a dashpot duty, the transmission gear is set to neutral (out of gear) when the rotation speed decreases after dashpot control. If the drive wheels were disconnected from the engine by doing so, or by disengaging the clutch, the rotational speed would drop rapidly and there was a risk that the engine would stall.

The present invention has been made in view of the above-mentioned problems, and provides an idle speed control device that can prevent a sudden drop in engine speed even if the drive wheels and the engine are disconnected during deceleration during idling operation. The purpose is to

<Means for Solving the Problems> Therefore, in the present invention, as shown in FIG. In an idle rotation speed control device for an internal combustion engine, the idle rotation speed control device for an internal combustion engine is equipped with an idle rotation speed control means that controls the idle rotation speed by outputting a pulse signal having a corresponding valve opening duty and controlling the opening degree of the idle control valve. an idle operating state detection means for detecting the operating state; a rotational speed reduction rate detection means for detecting the reduction rate of the engine rotational speed; Dashpot signal output means is provided for outputting a dashpot signal for increasing and correcting the valve opening duty.

<Operation> With this configuration, when the engine is in an idling operating state and the rate of decrease in the engine speed is greater than or equal to a predetermined rate, the opening duty of the idle control valve is increased and corrected by the dashpot signal. Therefore, regardless of whether the engine is in an idling state (idle switch OFF → ON), the dashpot duty is added due to the actual drop in rotational speed, and the transmission gear is set to neutral during deceleration. Even when the drive wheels are disconnected from the engine and the rotational speed drops, such as when the engine is turned on or the clutch is disengaged, a dashpot duty is added to prevent a sudden drop in rotational speed.

<Example> The present invention will be explained in detail below.

The hardware configuration is the same as the conventional one shown in FIG. 4, and only the software configuration related to dashpot control is different, so only this software configuration will be explained.

FIG. 2 shows a basic flowchart of an embodiment of the present invention, in which the steps (indicated as S in the figure,
(The same applies hereafter) In 1, the basic valve opening duty (time ratio of ON in the pulse cycle) ISC6 of the pulse signal supplied to the idle control valve 3 is calculated based on the engine operating state such as water temperature, as in the conventional case. . The idle rotation speed is controlled by outputting a pulse signal having this basic valve opening duty l500 to the idle control valve 3, and this functions as idle rotation speed control means.

In step 2, the basic quantity valve duty rsc0 calculated in step 1 is set as the valve opening duty ISC of the pulse signal supplied to the idle control valve 3.

In step 3, it is determined whether the flag is 1 or 0. Here, the flag is set to 1 in step 7, which will be described later, when the dashpot control conditions are met.

Here, if it is determined that the flag is O, the process proceeds to step 4, which functions as an idle operation state detection means, and the idle switch (ON when the intake throttle valve 1 is fully closed) signal is turned ON.
- It is determined whether the engine is OFF, and if it is ON, that is, when the engine is in an idling state, the process proceeds to step 5.

In step 5, which functions as a rotation speed reduction rate detection means, the change rate of the actual rotation speed N (a value obtained by subtracting the previous value from the current detected rotation speed) ΔN is set to a negative predetermined value ΔN.
, is smaller than . Here, ΔN × ΔN
, and when it is determined that the rotational speed N is decreasing at a rate higher than a predetermined rate, for example, the drive wheel and the engine are disconnected due to a gear dropout or clutch disengagement operation during deceleration, and the rotational speed N decreases. If so, proceed to step 6.

On the other hand, when it is determined in step 4 that the idle switch signal is OFF, and when it is determined in step 5 that the rate of decrease in the rotation speed N is below a predetermined value, step 8
Then, a pulse signal having the valve opening duty ISC set in step 2 is output to the idle control valve 3.

If the idle switch signal is ON and it is determined that the rotational speed N is decreasing at a rate higher than a predetermined rate and the process proceeds to step 6, the calculation settings are made to prevent the rotational speed N from dropping as shown in Figure 3. Dashpot duty IS
O,, and the basic valve opening duty r calculated in step 1
sc, and set as the valve opening duty ISO of the pulse signal supplied to the idle control valve 3. This step 6 functions as a dashpot signal output means, and the additional control of this dashpot duty ■5Cdp prevents a sudden drop in the rotational speed N due to gear dropout during deceleration, etc. be.

Then, in order to indicate that the dashpot control has been performed, a flag is set to 1 in the next step 7, and in step 8, a pulse signal having the valve opening duty ISC set in step 6 is output to the idle control valve 3.

In this way, when the dashpot control condition is satisfied, the dashpot duty is added, and the flag is set to 1, the flag is determined to be 1 in step 3 next time, and the steps from step 3 to Proceed to 9.

In step 9, a predetermined duty α is subtracted from the dashpot duty 5Cdp calculated and set in step 6, and the result is set as a new dashpot duty ISC,p.

Then, the dashpot duty l obtained by this subtraction
It is determined in step 10 whether 5Cdp is a value near zero, and if it is determined that it is not a value near zero, step 1 is performed.
1, and add the newly set dashpot duty 15Cd by subtracting it in step 9 and the basic valve opening duty 13C calculated in step 1 to generate a pulse signal to be supplied to the idle control valve 3. Valve opening duty I
In step 8, a pulse signal having the valve opening duty TSC set in step 11 is output to the idle control valve 3.

On the other hand, if it is determined in step 10 that the dashpot duty l5Cdp subtracted in step 9 is approximately zero, the flag is set to 0 in step 12 and the process proceeds to step 8. A pulse signal with a valve duty ISC is output to the idle control valve 3.

That is, in steps 9 to 12, when the dashpot control conditions are complete, the dashpot duty rsc.

3, the dashpot duty l5Cdl is gradually decreased linearly as shown in FIG.

In this embodiment, the amount of change in the rotational speed N is directly calculated as the rotational speed reduction rate detection means, but the rotational speed N
Clutch operation (which causes a sudden decrease in
It is also possible to detect a clutch disengagement (clutch disengagement) or gear operation (shift to neutral), thereby indirectly detecting a large rate of decrease in the rotational speed.

<Effects of the Invention> As explained above, according to the present invention, the dashpot duty is added when the engine speed decreases at a predetermined rate or more when the engine is in an idling operating state, thereby preventing gear disengagement during deceleration. This has the effect of suppressing a sudden drop in rotational speed caused by such problems.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of the present invention, FIG. 2 is a flowchart of dashpot control according to an embodiment of the present invention, FIG. 3 is a time chart for explaining dashpot control of the same embodiment, and FIG. FIG. 5 is a hardware configuration diagram for explaining the conventional example, and a time chart for explaining dashpot control in the conventional example. 1... Intake throttle valve 2... Auxiliary air passage 3.
... Idle control valve 4 ... Control unit 5 ... Engine main body Patent applicant Japan Electronics Co., Ltd. Agent Patent attorney Fujio Sasashima Figure 5 @ Figure 4

Claims (1)

[Claims] The idle control valve opening degree is controlled by outputting a pulse signal having a valve opening duty according to the operating state of the engine to the idle control valve installed in the auxiliary air passage that bypass connects the upstream and downstream of the intake throttle valve. An idle rotation speed control device for an internal combustion engine, which includes an idle rotation speed control means for controlling an idle rotation speed, comprising an idle operation state detection means for detecting an idle operation state of the engine, and a rotation speed for detecting a reduction rate of the engine rotation speed. A reduction ratio detection means and a dashpot signal output means for outputting a dashpot signal for increasing the valve opening duty of the pulse signal when the reduction ratio of the engine speed is equal to or higher than a predetermined value in an idling state are provided. Features: Idle speed control device for internal combustion engines.