JPS62153540A - Deceleration controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To secure the superior deceleration feeling by installing a control unit which reduction-corrects the initial value of the opening control of an air flow rate control valve, increasing the rate of reduction according to the lapse of time after the start of deceleration, thus obtaining the smooth deceleration of an engine. CONSTITUTION:A air flow rate control valve 3 whose opening degree is adjusted according to the duty ratio is installed into an auxiliary air passage 2 which bypasses an intake throttle valve 1. An air fuel ratio correcting means in deceleration is constituted of an initial control quantity setting means and a correcting means. The correcting means decrease-corrects the initial value of the opening control of the air flow rate control valve 3 which is set by the initial control setting means, increasing the rate of reduction according to the time of lapse after the start of deceleration. Thus, engine deceleration can be carried out smoothly, and the superior deceleration feeling can be obtained.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a deceleration control device for an internal combustion engine.

<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 as an air flow control valve is installed in the engine, and the opening degree of the idle control valve 3 is controlled by a control unit according to the engine operating state based on the engine speed, engine cooling water temperature, etc.
An idle rotation speed control device is provided which controls the idle rotation speed by increasing or decreasing the duty ratio of the pulse signal from the throat 4. still,
5 is an engine body, 6 is an air flow meter, and 7 is an air cleaner.

By the way, such an idle speed control device is equipped with an anti-afterburn valve (A
An air-fuel ratio correction function during deceleration, which corresponds to the BV) function, is provided.

This is because when the fuel in the intake manifold flows into the combustion chamber immediately after deceleration when the intake throttle valve 1 is fully closed, the air-fuel ratio becomes overrich and is discharged directly to the exhaust system without ignition. Heat causes afterburning, which adversely affects the exhaust system. To prevent this, air is introduced into the intake manifold during deceleration, and the amount of air is adjusted by adjusting the opening of the idle control valve 3. It is designed to be controlled by

<Problems to be Solved by the Invention> In the conventional air-fuel ratio correction control during deceleration, the idle control valve 3 immediately before deceleration is adjusted based on the engine cooling water temperature and the intake air flow rate.
The initial opening control amount, that is, the initial duty ratio of the pulse signal of the air-fuel ratio correction bone is determined, and thereafter, during deceleration, the duty ratio of the air-fuel ratio correction bone is decreased at a constant rate until it becomes zero. (shown by the solid line in Figure 5).

However, with the conventional setting of the initial duty ratio and reduction rate, the deceleration response of the engine is poor, resulting in a deceleration state with a feeling of acceleration, which is dangerous when driving in a city.

Therefore, in order to improve this problem, it is possible to consider measures such as lowering the setting level of the initial duty ratio or increasing the rate of decrease (indicated by the chain line in Fig. 5). Although the deceleration state accompanied by this can be resolved, a problem arises in that the deceleration shock becomes large.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a deceleration control device that performs an air-fuel ratio correction function during deceleration so that a pleasant feeling of deceleration can be obtained without increasing deceleration shock.

Means for Solving the Problems> For this reason, in the present invention, as shown in FIG. 1, the auxiliary air passage bypassing the intake throttle valve is driven by a pulse signal and its opening degree is adjusted according to its duty ratio. In an internal combustion engine, the internal combustion engine is provided with an air-fuel ratio correction means for controlling the opening of the air-flow control valve during deceleration to prevent an air-fuel ratio overrich during deceleration, the air-fuel ratio correction means for deceleration. an initial control amount setting means for setting an initial value of the opening control amount of the air flow control valve based on the operating state at the start of deceleration, and an initial control amount setting means for setting the initial value set by the initial control amount setting means from the start of deceleration. and a correction means for correcting the decrease while increasing the rate of decrease according to the elapsed time.

In the above configuration, upon detection of deceleration, the initial valve opening control amount of the air-fuel ratio correction bone of the air flow control valve is set based on the operating state at the time of detection, and the initial valve opening control amount of the air-fuel ratio correction bone during deceleration is set. Air flow rate is determined. Thereafter, the initial set value of the air-fuel ratio correction bone is decreased by increasing the rate of decrease according to the elapsed time from the start of deceleration until the air-fuel ratio correction bone becomes zero, so that overrich can be prevented at the beginning of deceleration. Since a sufficient amount of air can be supplied to the engine, deceleration shock due to misfires etc. will not increase, and the slope of decrease in air amount will increase over time, allowing smooth deceleration of the engine and good deceleration. You will be able to feel the sensation.

<Example> Hereinafter, an example of the present invention will be described based on the drawings. still,
The hardware configuration is the same as the conventional one shown in FIG. 6, and only the software configuration related to air-fuel ratio correction control during deceleration differs, so only this software configuration will be described below.

FIG. 2 is a flowchart regarding air-fuel ratio correction control during deceleration according to an embodiment of the present invention.

In the figure, at Sl, data such as engine speed, cooling water temperature, and intake air flow rate are inputted from a crank angle sensor, water temperature sensor 2, and air flow meter, respectively, and data from an idle switch.

In S2, it is determined whether the vehicle is decelerating or not based on whether the idle switch is ON or OFF. When it is determined that deceleration is occurring, the process proceeds to S3, where it is determined whether the deceleration determination is the first time or the second time or later, that is, whether it is at the start of deceleration or in the middle of deceleration.
ES), that is, at the start of deceleration, the process advances to S4.

In S4, based on the initial control amount map of the air-fuel ratio correction valve during deceleration shown in FIG. 3, the initial control amount of the air-fuel ratio correction valve during deceleration at the time of starting deceleration, that is, the duty factor Set the initial value of the ratio (initial control amount setting function). Next, in step 85, the reduction rate characteristic of the controlled variable based on the engine speed at the start of deceleration as shown in FIG. 4 is selected, and the reduction rate is searched according to the elapsed time.
The decrease rate retrieved at 85 is subtracted from the current control amount of the air-fuel ratio correction valve during deceleration (decrease correction function).

Then, in S7, it is determined whether the subtraction calculation value in S6 has become zero, and if it is not zero, the reduction rate is searched again based on the elapsed time, and the previous subtraction calculation value is set as the current control amount. The searched reduction rate is subtracted from the control amount. In this way, the control amount of the air-fuel ratio correction bone during deceleration is gradually corrected by subtraction until it becomes zero.

In this way, it is possible to ensure a sufficient amount of intake air in the early stages of deceleration to prevent overrichness and to take measures against emissions, and it is also possible to hasten the decrease in the air-fuel ratio correction bone during deceleration. Therefore, the deceleration shock immediately after deceleration does not increase, and moreover, the engine speed can be smoothly lowered and a pleasant deceleration feeling can be obtained (indicated by the broken line in FIG. 5).

Although this embodiment shows an example in which the reduction rate is increased based on the elapsed time from the start of deceleration, the reduction rate is not limited to this, and the reduction rate may be set based on the engine speed at that time.

<Effects of the Invention> As described above, according to the present invention, the reduction rate of the control amount of the deceleration air-fuel ratio correction valve is increased as the elapsed time from the start of deceleration increases, so that the deceleration air-fuel ratio correction The air in the valve i1 can decrease rapidly with the passage of time. Therefore, the vehicle can be decelerated quickly without increasing deceleration shock, and the feeling of deceleration can be improved.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of the present invention, Fig. 2 is a control flowchart of an embodiment of the present invention, Fig. 3 is an initial control amount setting characteristic diagram used in the above embodiment, and Fig. 4 is an implementation of the same as above. The controlled variable reduction rate characteristic diagram used in the example, FIG. 5, shows the difference between the present invention and the conventional example. Figure 6 is a hardware configuration diagram to explain the conventional example.■... Intake throttle valve 2... Auxiliary air passage 3...
・Idle control valve (air flow control valve) 4... Control unit 5... Engine body 6...
Air Flow Meter Patent Applicant Japan Electronics Co., Ltd. Representative Patent Attorney Fujio Sasashima Figure 1 Figure 2 Figure 3 Inhalation! Nine points large figure 4

Claims (1)

[Claims] The auxiliary air passage that bypasses the intake throttle valve has an air flow control valve that is driven by a pulse signal and whose opening degree is adjusted according to its duty ratio, and when decelerating, the opening degree of the air flow control valve is controlled during deceleration. In an internal combustion engine equipped with a deceleration air-fuel ratio correction means for preventing an air-fuel ratio overrich during deceleration, the deceleration air-fuel ratio correction means adjusts the initial opening control amount of the air flow rate control valve based on the operating state at the start of deceleration. The present invention is comprised of an initial control amount setting means for setting a value, and a correction means for decreasing the initial value set by the initial control amount setting means while increasing the rate of decrease according to the elapsed time from the start of deceleration. Characteristic deceleration control device for internal combustion engines.