JPH01294933A - Auxiliary air control device for internal combustion engines - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

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

<Prior art> As an auxiliary air control device for an internal combustion engine, an auxiliary air control valve is installed in an auxiliary air passage that bypasses a throttle valve, and the opening degree of the auxiliary air control valve is increased or decreased under idling operating conditions. There is one that controls the rotational speed to an optimal value.

In addition to this idle speed control function, there is also a deceleration air-fuel ratio correction function (anti-afterburn valve function) as a measure to prevent afterburn caused by over-enrichment of the air-fuel ratio during deceleration.
Some models are equipped with a deceleration negative pressure correction function (boost control valve function) to keep the negative pressure in the intake manifold constant during deceleration.
(See Publication No. 62362).

The above-mentioned deceleration air-fuel ratio correction function means that if the wall-flow fuel in the intake manifold flows into the combustion chamber during deceleration when the throttle valve is fully closed due to a delay in fuel transportation due to fuel adhesion to the wall surface, the air-fuel ratio correction function When the fuel ratio becomes too rich, it is discharged directly to the exhaust system without igniting, causing afterburn due to secondary air and exhaust heat, which has a negative impact on the exhaust system. To prevent this, the intake manifold is It introduces air.

In addition, the deceleration negative pressure correction function means that during deceleration when the throttle valve is fully closed, the negative pressure in the intake manifold increases and becomes high boost, resulting in insufficient compression pressure and incomplete combustion, resulting in unburned gas (HC). ) and cause oil to rise, so to prevent this, air is introduced into the intake manifold during deceleration.

In order to perform the deceleration air-fuel ratio correction function and the deceleration negative pressure correction function, the auxiliary air control valve must be controlled. For example, Ii (opening degree) is set as follows.

In other words, the deceleration air-fuel ratio correction ABV is calculated as the engine intake air flow f.
It is stored in a map according to Q, and the map is referenced and set when decelerating. Further, the deceleration negative pressure correction needle BCV is stored in a map according to the engine speed N, and is set by referring to the map during deceleration. In order to control the idle speed, a basic idle speed control component l5CT□ that depends on engine cooling water temperature and a feedback control component that is increased or decreased based on the comparison result by comparing the engine speed with the target idle speed under idle operating conditions. The idle rotation speed control portion ISC+n (= r S
C? w+ I S CCL+・), deceleration air-fuel ratio correction ABV, and deceleration negative pressure correction needle BCV, select the largest one among these, and control based on this? 11
f is set.

<Problem to be Solved by the Invention> Incidentally, in order to miniaturize the auxiliary air control valve, recent auxiliary air control devices also forcibly open the throttle valve at low temperatures in response to the engine cooling water temperature. Equipped with a wax type throttle opener.

In addition, under idle operating conditions (idle rotation speed feedback control conditions), the deviation ΔISC,L from the reference value for the feedback control component is learned, and based on this, the learning control component l5CL,l is set, and the control amount is corrected thereby. ,
Absorbs component variations. That is, ABV, BC
If the maximum value among the three of V and ISC+n is ISC, then I S Co, = 1 S Ct + I S Ct *
The control amount is set based on this l5COH.

However, since the learning control portion l5cL,l is a correction value for the deviation from the target idle speed under the idle speed feedback control condition, when the deceleration air-fuel ratio correction amount ABV or the deceleration negative pressure correction needle BC■ is selected. ,
If this is corrected by the learning control portion l5cLll and the control amount is set, there is a problem in that a large deviation occurs from the required output in the case of the original deceleration air-fuel ratio correction or deceleration negative pressure correction.

That is, as shown in FIG. 4, the engine required air flow rate is divided into the opener portion and the auxiliary air control valve portion, and the learning control portion l5CL, l is divided by the opener portion.
(The learning control component l5CLR always varies greatly depending on each water temperature due to the characteristics of the opener, etc.) Therefore, it is not possible to use this to correct the deceleration air-fuel ratio correction amount ABV or the deceleration negative pressure correction needle BCV. There is no meaning at all, and a bounce occurs.

In view of these conventional problems, the present invention provides an auxiliary air control device for an internal combustion engine that can improve the deceleration air-fuel ratio correction function and the deceleration negative pressure correction function even if there are variations in the throttle opener, etc. The purpose is to provide

<Means for Solving the Problems> Therefore, as shown in FIG.
J constitutes an auxiliary air control device for an internal combustion engine.

(A) Auxiliary air control valve installed in the auxiliary air passage that bypasses the throttle valve. (B) Deceleration air-fuel ratio correction setting means for setting the auxiliary air flow rate for deceleration air-fuel ratio correction according to the engine intake air flow rate during deceleration. (C) Deceleration negative pressure correction setting means for setting the auxiliary air flow rate for deceleration negative pressure correction according to the engine speed during deceleration (D) Sets the auxiliary air flow rate for basic idle speed control according to the engine cooling water temperature Idle rotation speed control basic portion setting means (E) Feedback control portion setting means that compares the engine rotation speed with the target idle rotation speed under idle operating conditions and increases or decreases the auxiliary air flow rate for feedback control based on the comparison result. (F) Learning control portion setting means for learning the deviation from a predetermined reference value for the feedback control portion under idling operating conditions and setting the auxiliary air flow rate for the learning control portion based on the deviation; (G) the basic portion of the idle rotation speed control; Idle rotation speed control portion setting means (H) for setting an idle rotation speed control portion as a sum of the feedback control portion and the learning control portion; Selection means (I) for selecting the largest value among the selected values; (J) control means for controlling the opening degree of the auxiliary air control valve by setting a control amount based on the selected value; (J) responding to the engine cooling water temperature; Throttle opener that forcibly opens the throttle valve when the temperature is low (Function) In the above configuration, the deceleration air-fuel ratio correction amount AB during deceleration
V is set by the engine intake air flow rate Q, and the filtration rate negative pressure correction BCV is set by the engine rotation speed N.

In addition, the idle speed control basic portion ■SCT, 1 is set according to the engine cooling water temperature, and under idle operating conditions, the engine speed is compared with the target idle speed and the feedback control portion l5CcL is increased or decreased based on the comparison result. Set,
Furthermore, under idling operating conditions, the deviation Δ■5CcL from the reference value for the feedback control component is learned, and the learning control component ■SCL,l is set based on this. And basic idle speed control ■5CT1. As the sum of I, feedback control portion ■5CoL, and learning control portion l5CLR,
Idle rotation speed control portion I S C + o (= I S
c, ,+I S CCL+ l5CLII).

Then, the deceleration air-fuel ratio correction ABV and the deceleration negative pressure correction BC
Select the largest value from V and the idle speed control portion ISC+n, set the control amount based on this,
Controls the opening of the auxiliary air control valve.

In this way, when selecting the deceleration air-fuel ratio correction amount ABV or the deceleration negative pressure correction amount BCV, a proper ratio is achieved by not making corrections based on the learning control portion ①SCL,I.

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

In FIG. 2, air from an air cleaner 1 passes through an intake duct 2, passes through a throttle valve 3 that is linked to an accelerator pedal (not shown), and an electromagnetic auxiliary air passage 4 that bypasses the throttle valve 3. It is inhaled under the control of the control valve 5. And intake manifold 6
The mixed fuel is mixed with the fuel injected from the fuel injection valve 7 and sucked into the engine 8.

In addition, the throttle valve 3 has a temperature sensing section in the engine cooling water passage (
(not shown), and is provided with a wax type throttle opener 20 that forcibly opens the throttle valve 3 from the fully closed position at low temperatures in response to the engine cooling water temperature Tw.

The opening degree of the auxiliary air control valve 5 is controlled by a control signal from a control unit 9, and for this control, signals from various sensors are input to the control unit 9.

As the various sensors described above, a hot wire air flow meter 10 is provided in the intake duct 2 to detect the intake air flow rate Q. Further, a rotation speed sensor 11 is provided to detect the engine rotation speed N. Further, a water temperature sensor 12 is provided to detect the engine cooling water temperature Tw.

Further, the throttle valve 3 is provided with a potentiometer-type throttle sensor 13 to detect the throttle valve opening TVO. In addition, the idle switch 14 is turned ON when the throttle valve 3 is in the fully closed position. Neutral switch that turns ON when the transmission is in the neutral position15. A start switch 16 which is turned ON when the engine key switch is in the start position is provided.A vehicle speed sensor 17 for detecting vehicle speed VSP is provided.

Here, the microcomputer in the control unit 9 performs arithmetic processing according to the flowchart in FIG. 3 based on the signals from the various sensors, and controls the opening degree of the auxiliary air control valve 5.

The routine shown in FIG. 3 is executed at predetermined intervals (for example, every 10 m5).

Step 1 (denoted as SL in the figure; the same applies hereinafter) includes intake air flow rate Q9, engine speed N, water temperature TW, throttle valve opening TVO, vehicle speed ■SP, and ON/O of various switches.
Read the FF signal.

In step 2, it is determined whether the idle operating condition (idle rotation speed feedback control condition) is met.

Here, the idle speed feedback control conditions are:
Vehicle speed VSP is 8 km/h or less, idle switch 14
is ON and a certain amount of time has passed since it was turned ON.

The condition is that the neutral switch 15 is ON and the start switch 16 is OFF.

In the case of the idle rotation speed feedback control condition, the process proceeds to step 3 and feedback control is performed. That is,
The magnitude of the target idle rotation speed Ns dependent on the water temperature Tw is compared with the actual idle rotation speed N, and the feedback control portion l5CcL is increased or decreased and set using well-known proportional/integral control. This step 3 corresponds to a feedback control amount setting means.

Next, proceed to step 4 to perform learning. That is, a predetermined reference value (usually O) of the feedback correction numerator 5cct
A rewritable R that stores the learning control portion l5CLR corresponding to the water temperature Tw while learning the deviation Δl5CCL from
Learning control portion corresponding to the current water temperature Tw from the AM map
5CLR is read out, and this learning control portion ①SCL,I is updated based on the following formula, and the data in the RAM map is rewritten. This step 4 corresponds to a learning control amount setting means.

■SCL, I+l5CLR+ΔI S C,, /M(M
is a constant) Next, the process proceeds to step 5, where the deceleration air-fuel ratio correction AB■ and the deceleration negative pressure correction BCV are each set to 0.

Thereafter, the process proceeds to step 13, which will be described later.

If it is not the idle speed feedback control condition,
Proceeding to step 6, the throttle valve opening change amount ΔTVO, which is the difference from the previous value of the throttle valve opening T■O, is set to a predetermined value (
For example, by determining whether or not the speed is -1.6 deg/10 m5) or less, it is determined whether or not deceleration is required.

When not decelerating, proceed to step 7 and set idle switch 1.
4 is ON or not, and if the throttle valve 3 is open and the idle switch 14 is OFF, the process proceeds to step 8.

In step 8, the map in which the deceleration air-fuel ratio correction amount ABV is determined according to the intake airflow IQ is referred to, and the deceleration air-fuel ratio correction amount ABV is
Set BV. This step 8 corresponds to a deceleration air-fuel ratio correction amount setting means.

Next, in step 9, the map in which the deceleration negative pressure correction amount BCV is determined according to the engine speed N is referred to, and the deceleration negative pressure correction amount BCV is determined according to the engine speed N.
Set V. This step 9 corresponds to a deceleration negative pressure correction amount setting means. After that, the process proceeds to step 13, which will be described later.

When deceleration is started from this state, the process directly proceeds from step 6 to step 13, which will be described later, and the deceleration air-fuel ratio correction amount ABV and deceleration negative pressure correction amount BCV that were set immediately before starting deceleration are maintained.

When the throttle valve 3 is fully closed due to deceleration (coasting state), the process proceeds to step 10 via step 6.7, where the deceleration air-fuel ratio correction amount ABV is decreased by a predetermined reduction amount. Next, in step 11, the deceleration air-fuel ratio correction amount ABV is
If ABV<0, then in step 12 the ABV
=O. After that, the process proceeds to step 13, which will be described later.

Next, in step 13, a basic idle speed control portion l5CT is set with reference to a map in which the basic idle speed control portion l5CTW is determined according to the water temperature Tw. This step 13 corresponds to the idle rotation speed control basic portion setting means.

Next, in step 14, the idle rotation speed control portion l5C11
1 is set using the following formula. This step 130 corresponds to an idle rotation speed control portion setting means.

I 5CID= I SCyw+ I 5CCL+ I
SCt+++l5CAS Here, as ISC,, the one set in step 13 is used. As l5CcL, the one set in step 3 is used during idle rotation speed feedback control, and the clamped one is used at other times. As 15CL11, the one retrieved from the RAM map based on water 1rW is used. ISC□ is a correction bone at the time of starting, and the water temperature T is maintained while the start switch is ON (during cranking) and for a predetermined time after the start switch is OFF.
It is determined corresponding to w.

Next, in step 15, the deceleration air-fuel ratio correction ABV, the deceleration negative pressure correction BCV, and the idle rotation speed control ■S C+ o
Based on the comparison result, proceed to step 16, 17 or 18 and select the largest auxiliary air flow rate IS.
Let Ct (27m1n). This step 15-1
The part 8 corresponds to the selection means.

Next, in step 19, the auxiliary air flow rate ISC, (A/1I
lin) and the battery voltage correction bone l5CvB,
Final auxiliary air flow rate r S CON (j2/m1n
) -ISC1+ISCvm is calculated.

Next, in step 20, the auxiliary air flow rate l5Co, 4(1/
n+in) is the control amount, duty ratio DUTY (%
) and output. This step 20 corresponds to the control means.

When the duty ratio DUTY is set in this way,
The pulse signal of this duty ratio energizes the valve opening coil of the auxiliary air control valve 5, thereby controlling the opening degree.
The desired auxiliary air flow rate is obtained.

<Effects of the Invention> As explained above, according to the present invention, the idle rotation speed control numerator sc+o (= I S Ctw
+ IS CCL + IS CLII),
The largest one is selected, the control amount is set based on this, and the opening degree of the auxiliary air control valve is controlled. When the deceleration air-fuel ratio correction amount ABV or the deceleration negative pressure correction amount BCV is selected, the learning control amount is Since the correction using l5CL and l is not performed, even if there are variations in the throttle opener, etc., it is possible to improve the deceleration air-fuel ratio correction function and the deceleration negative pressure correction function.

[Brief explanation of the drawing]

Fig. 1 is a functional block diagram showing the configuration of the present invention, Fig. 2 is a system diagram showing an embodiment of the invention, Fig. 3 is a flowchart showing control details, and Fig. 4 explains problems with the conventional technology. This is a diagram for 3... Throttle valve 4... Auxiliary air passage 5
...Auxiliary air control valve 7...Fuel injection valve 8.
... Engine 9 ... Control unit 10.
・・Air flow meter 11・・Rotation speed sensor
12... Water temperature sensor 13... Throttle sensor 14... Idle switch 20... Throttle opener - Patent applicant Japan Electronics Co., Ltd. Agent Patent attorney Fujio Sasashima

Claims (1)

[Scope of Claims] An auxiliary air control valve installed in an auxiliary air passage that bypasses a throttle valve, and a deceleration air-fuel ratio correction part that sets the auxiliary air flow rate for deceleration air-fuel ratio correction according to the engine intake air flow rate during deceleration. a deceleration negative pressure correction setting means for setting an auxiliary air flow rate for deceleration negative pressure correction according to the engine speed during deceleration; and a deceleration negative pressure correction setting means for setting the auxiliary air flow rate for basic idle speed control according to the engine cooling water temperature. Idle rotation speed control basic portion setting means for setting; and feedback control portion setting means for comparing the engine rotation speed with a target idle rotation speed under idle operating conditions and increasing or decreasing an auxiliary air flow rate for feedback control based on the comparison result. , learning control portion setting means for learning a deviation from a predetermined reference value for the feedback control portion under idle operating conditions and setting an auxiliary air flow rate for the learning control portion based on the deviation; an idle rotation speed control portion setting means for setting an idle rotation speed control portion as a sum of the number of minutes and the learning control portion; , a selection means for selecting the largest value; a control means for setting a control amount based on the selected value to control the opening degree of the auxiliary air control valve; An auxiliary air control device for an internal combustion engine, comprising: a throttle opener that forcibly opens; and an auxiliary air control device for an internal combustion engine.