JPS6183463A - Deceleration controller for internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent an overrich mixture from occurring, by measuring a fuel quantity being so far injection-supplied in time of engine deceleration, while driving an idling control valve according to this fuel quantity. CONSTITUTION:A degree of engine deceleration is detected by an engine deceleration detecting device C. On the basis of a fuel quantity Q sprayed so far prior to deceleration, opening of an idling control valve corresponding to an air quantity being short is calculated by an idling control valve opening operational device E. An idling control valve B is driven according to the opening of this idling control valve. With this constitution, overrichness in an air-fuel mixture is preventable.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Fields> The present invention is directed to a so-called single point injection (SP
The present invention relates to a deceleration control device for an internal combustion engine, which is equipped with a [) system and an idle control valve (rsc valve) provided in an auxiliary air passage that bypasses a throttle valve.

<Prior Art> For example, as shown in FIG. 5, a fuel injection valve 4 is provided at a gathering portion 2 of an intake passage 1 (in this case, upstream of a throttle valve 3), and fuel for each cylinder of an internal combustion engine 5 is injected from the fuel injection valve 4. The SPI system that intensively injects and supplies fuel is widely used because a single fuel injection valve is sufficient and control is easy.

In addition, an auxiliary air passage 6 is provided that bypasses the throttle valve 3, and the opening of the idle control valve 7 provided in the passage 6 is adjusted by the pulse signal output of the control unit 8 that receives the large force of the engine operating state, and the amount of intake air is adjusted. and controls the idle speed of the engine. ” <Problem to be solved by the invention> However, according to the above-mentioned SPI type internal combustion engine, there is a long intake passage including a branch part from the time the fuel is injected until it is taken into the combustion chamber of the engine, and the inner wall of this passage has a long intake passage. The injected fuel adheres to the engine.Therefore, a difference occurs between the actual injection amount and the engine intake fuel amount, and a response delay inevitably exists.

For this reason, if you close the throttle valve and suddenly decelerate the engine, even if the fuel injected from the fuel injection valve is cut or Nff
1, the pressure on the inner wall of the intake passage downstream of the throttle valve increases rapidly, and the fuel adhering to the inner wall of the intake passage vaporizes rapidly, causing the mixture ratio of the intake air-fuel mixture to become too rich, resulting in a misfire and afterburn. Alternatively, the exhaust properties may deteriorate, fuel consumption may worsen, and the catalyst provided in the exhaust system may be easily damaged.

In view of the above, the present invention provides an idle control valve 7 during engine deceleration.
The purpose is to open the throttle valve by a necessary amount to supply intake air downstream of the throttle valve 3 to prevent over-enrichment of the air-fuel mixture and deterioration of deceleration performance due to excessive air supply.

Therefore, in the present invention, as shown in FIG. C, means for calculating the amount of fuel Q injected before deceleration of the engine, and means E for calculating the opening degree of the idle control valve according to the amount of air that is insufficient during deceleration in accordance with the amount of fuel. , pulse signal output means F for adjusting the opening degree of the idle control valve B based on the output signal of the means during engine deceleration.

<Operation> As a result, when the engine deceleration detecting means C detects deceleration of the engine, idle control is performed to control the opening degree of the idle control valve according to the insufficient amount of air based on the fuel fiQ injected before the deceleration. The valve opening calculation means E performs calculations, and the opening of the idle control valve B is adjusted by the pulse signal output means F based on the calculation results of the means E, and the necessary amount of air is supplied downstream of the throttle valve, and the mixing is performed. Avoid deterioration in deceleration performance due to over-concentration and over-thin air.

<Example> An embodiment of the present invention will be described below.

As shown in FIG. 2, an idle control valve 13 is provided in the middle of the auxiliary air passage 12 that bypasses the throttle valve 11,
This adjusts the amount of auxiliary air and controls the idle rotation speed. As described above, the idle control valve 13 is configured for the purpose of adjusting the amount of auxiliary air for idle, but in the present invention, the opening area when fully opened is set to be large enough (as set) for air replenishment during deceleration. .

The idle control valve 13 is a rotary set, and a control unit 15 is installed in a valve opening coil and a valve closing coil (not shown).
The pulse signals are sent in a mutually inverted state, and the opening degree is adjusted according to the duty ratio of the pulse signals. 14 is an SF3 type fuel injection valve that injects and supplies fuel on the upstream side of the throttle valve 11.

The throttle sensor 16 detects the full opening of the throttle valve 11 and inputs this to the control unit 15.

The control unit 15 is a microcomputer consisting of an input/output processing unit, a central processing unit, and a storage device, and includes a rotation sensor 171 that detects the engine rotation speed, an air flow meter 18 that detects the intake air amount of the engine, and a cooling water of the engine. The injection pulse width Ti is determined by the detection signal of the engine operating state detection means 20 such as the water temperature sensor 19 that detects the temperature.
is calculated and output to the fuel injection valve 14, and the pulse signal of the idle control valve 13 is controlled to perform feedback adjustment of the valve opening degree when the engine is idling.

Next, a deceleration control flowchart of the control unit 15 shown in FIG. 3 will be explained. Note that this flowchart is executed at predetermined minute intervals by a program timer.

When the engine is idling based on signals from the throttle switch 16 and the rotation sensor 17, the operation of the idle control valve (ISC valve) is controlled in a separate routine.

If idle control is not being performed in Sl, it is determined that the vehicle is in a normal running state, and in S2 the amount of fuel injected from the fuel injection valve 14 is calculated based on the integrated value of the injection pulse width Ti, etc., and the value is recorded in 41. put. This is the fuel fiQ in the present invention.
It is a calculation means.

In addition, since the amount of injected fuel is proportional to the amount of intake air, the amount of fuel i
Q can also be calculated based on the amount of intake air.

In S3, it is detected that the engine has entered a deceleration state.

As the engine deceleration detection means, a combination of the throttle sensor 16 and the rotation sensor 17 or the throttle sensor 16 may be used.
A combination of the air flow meter 18 and the air flow meter 18 is used. For example, it is determined that the engine is decelerating when the throttle sensor 16 detects a decrease in the opening degree or when it detects a fully closed position and the engine rotational speed is greater than the idle value.

When deceleration begins, the intake negative pressure downstream of the throttle valve 11 increases, and the fuel that had been adhering to the wall of the intake passage is rapidly vaporized and the air-fuel mixture tends to become richer. At this time, S4 focuses on the fact that there is a certain correlation between the engine fuel related to the amount of fuel adhering to the intake passage wall and the amount of injection injected before deceleration. The air amount shortage caused by this is determined in advance from the fuel iQ that has been injected and supplied so far, and this is mapped as the pulse output duty ratio to the idle control valve 14, and the output duty is read from the Q value. In the present invention, this function is referred to as idle control valve opening calculation means.

Then, the duty read in S5 is set to idle control valve 1.
4 to supply a predetermined amount of air downstream of the throttle valve 11 via the auxiliary air passage 12.
Open (pulse signal output means). This can prevent the engine intake air-fuel mixture from becoming over-enriched.

Incidentally, the amount of fuel vaporized from the intake passage wall during deceleration is greatest at the beginning of deceleration, and then gradually decreases. Therefore, a timer is used to measure time at 86 every predetermined unit time in S6, the output duty is gradually decreased in S7, and the output value of the idle control valve in S5 is decreased as shown in FIG.

When it is detected that the deceleration has ended in S8, the idle control valve 14 is closed or the idle rotation speed control 111 is started.
(ISO) is performed, and the deceleration control by the above-mentioned interrupt routine is completed.

In the above control, if the fuel injection valve 14 injects fuel even during deceleration, it goes without saying that the output duty to the idle control valve 14 must be corrected to compensate for this.

Furthermore, in order to calculate the injected fuel amount Q before the engine decelerates, the integration of Q may be stopped at this stage because when Q exceeds a predetermined value, the fuel adhering to the intake passage becomes approximately balanced.

<Effects of the Invention> As described above, according to the present invention, when the engine decelerates, the amount of fuel that has been injected and supplied so far is measured, and the amount of fuel that has been injected and supplied so far is measured, and the air shortage caused by the vaporization phenomenon of the fuel that adheres to the intake passage wall is detected. is calculated and the idle control valve is opened by the required amount, so even if the fuel adhering to the inner wall of the intake passage vaporizes when the engine decelerates, the engine is supplied with just the right amount of air depending on the amount of fuel. Can be supplied. This allows the air-fuel ratio of the mixture to be maintained at an appropriate value, preventing misfires due to over-enrichment.

Inconveniences such as afterburn, deterioration of exhaust properties, and damage to the catalyst can be prevented, and deterioration in deceleration performance due to excessive thinning can be prevented.

It is also highly effective in reducing vehicle shock during deceleration.

[Brief explanation of the drawing]

Fig. 1 is a diagram corresponding to the claims of the present invention, Fig. 2 is a longitudinal sectional view of the throttle valve section showing the configuration of the present invention, Fig. 3 is a control flowchart of the same control unit, and Fig. 4 is a throttle valve opening diagram in the same flowchart. FIG. 5 is a graph showing the relationship between the engine speed and the output duty to the idle control valve, and is a schematic configuration diagram of a conventional device. A...Fuel injection device B...Idle control valve C.
... Engine deceleration detection means D ... Injected fuel amount calculation means E ... Idle control valve opening calculation means F ... Pulse signal output means 11 ... Throttle valve 13 ...
Idle control valve 15...control unit 1
6...Throttle sensor 20...Engine operating state detection means Patent applicant: JEOL Ltd. representative Patent attorney Fujio SasashimaFigure 2

Claims (1)

[Scope of Claims] A fuel injection device that injects and supplies fuel to a gathering portion of an intake passage; an idle control valve that is provided in an auxiliary air passage that bypasses a throttle valve and whose opening degree is adjusted by a pulse signal according to the engine operating state; An internal combustion engine comprising: an engine deceleration detection means; a means for calculating an amount Q of fuel injected before engine deceleration; A deceleration control device for an internal combustion engine, comprising means for calculating the opening degree of a control valve, and pulse signal output means for adjusting the opening degree of the idle control valve based on an output signal of the means when the engine is decelerated. .