JP2650034B2 - Internal combustion engine deceleration control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a deceleration control device for an internal combustion engine.

<Conventional technology> In order to improve the fuel efficiency by keeping the idle speed of the internal combustion engine at an optimum value, in recent years, an auxiliary air control valve is interposed in an auxiliary air passage that bypasses a throttle valve, and the engine cooling water temperature and An idle speed control device is provided which controls the idle speed by increasing or decreasing the opening of the auxiliary air control valve in accordance with the engine operating state such as the engine speed.

Incidentally, the idle speed control device has a deceleration negative pressure correction function (boost control valve function) for keeping the intake pressure (negative pressure) in the intake manifold constant (for example, -620 mmHg) during deceleration. (See Jpn. Pat. Appln. KOKAI Publication No. 61-48915).

The above-mentioned deceleration negative pressure correction function means that during deceleration when the throttle valve is fully closed, the negative pressure in the intake manifold rises, the compression pressure becomes insufficient, combustion becomes incomplete, and unburned gas (HC) increases. In order to prevent deterioration of oil consumption, air is introduced into the intake manifold at the time of deceleration in order to prevent this.

In order to fulfill such a deceleration negative pressure correction function, the control amount (opening degree) of the auxiliary air control valve is set, for example, as follows.

That is, the deceleration negative pressure correction amount BCV is stored in a map according to the engine speed N, and is set with reference to the map. Then, the idle speed control component ISC _E set containing the basic characteristics of the water temperature dependent and feedback control amount and the like for controlling the idle speed, by comparing the deceleration negative pressure correction amount BCV, larger one The control amount is set based on the selection.

<Problems to be Solved by the Invention> However, in such a conventional deceleration control device, the auxiliary air flow rate of the deceleration negative pressure correction amount BCV gradually decreases due to the contamination of the auxiliary air control valve or the contamination of the throttle valve. In other words, the intake pressure will be smaller than the intake pressure set at the time of new product, for example, -620 mmHg, and the fuel injection amount should not use the low injection amount region which is a non-linear zone of the pulse width-injection amount characteristic of the normal fuel injection valve. Is set to a lower limit, so when the air flow rate decreases, it becomes over-rich and C
In view of such conventional problems, the present invention has a problem in that O, HC increases, coasting afterburn, engine stall, oil consumption, and the like. It is an object of the present invention to provide a deceleration control device for an internal combustion engine that can prevent a reduction in a deceleration negative pressure correction function due to component deterioration such as the above.

<Means for Solving the Problems> For this reason, as shown in FIG. 1, the present invention includes an auxiliary air control valve in an auxiliary air passage that bypasses the throttle valve, and through the auxiliary air control valve during deceleration, In an internal combustion engine deceleration control device that controls the intake pressure in the intake manifold by controlling the auxiliary air flow rate, the auxiliary air flow rate is controlled so that the intake pressure during deceleration matches the target intake pressure under predetermined feedback control conditions. Feedback control means for performing feedback control, learning storage means for learning and storing the feedback control result, and learning control means for controlling the auxiliary air flow rate using the learning result under conditions other than predetermined feedback control conditions. It was also done.

<Operation> If the auxiliary air flow rate is feedback-controlled so that the intake pressure during deceleration matches the target intake pressure, the intake pressure can be made substantially constant, and the auxiliary air control valve or the throttle valve becomes dirty. Further, it is possible to prevent the decrease in the deceleration negative pressure correction function.The feedback control result is learned and stored, and the auxiliary air flow rate is controlled using the learning result under a condition other than the predetermined feedback control condition. <Embodiment> 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 and a throttle valve 3 interlocked with an accelerator pedal (not shown) and an electromagnetic auxiliary air interposed in an auxiliary air passage 4 that bypasses the throttle valve 3. Under the control of the control valve 5, it is sucked. Then, the fuel is mixed with the fuel injected from the fuel injection valve 7 in the intake manifold 6 and is sucked into the engine 8.

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

As the various sensors, an intake sensor 10 is provided in the intake manifold 6, and detects an intake pressure PB. Further, a rotation speed sensor 11 is provided to detect the engine rotation speed N. An atmospheric pressure sensor 12 is provided to detect the atmospheric pressure P.
The throttle valve 3 is provided with a potentiometer type throttle sensor 13 for detecting the throttle valve opening TVO. In addition, there are provided an idle switch 14 which is turned on when the throttle valve 3 is fully closed, a neutral switch 15 which is turned on when the transmission is in a neutral position, and a vehicle speed sensor 16 for detecting a vehicle speed VSP.

Here, the microcomputer in the control unit 9 controls the opening degree of the auxiliary air control valve 5 by performing arithmetic processing based on signals from the various sensors in accordance with the flowcharts of FIGS.

The BCV control routine shown in FIG.
s) is executed every time.

In step 1 (shown as S1 in the figure, the same applies hereinafter), the intake pressure PB, the engine speed N, the altitude ALT, and the like are read.

The altitude ALT is obtained from the atmospheric pressure P with reference to a map by the routine of FIG. 4 executed as a background job (BGJ). Therefore, the atmospheric pressure P may be used as it is as a parameter of the altitude ALT used below.

In step 2, it is determined whether a predetermined learning condition (feedback control condition) is satisfied. Here, the predetermined learning condition is a condition that the throttle valve 3 is fully closed and a predetermined time has elapsed.

In the case of the learning condition, the process proceeds to step 3 and the engine speed N
The target value of the intake pressure PB is set by searching with reference to a map in which the target value of the intake pressure PB is determined according to the altitude and the altitude ALT.

Next, at step 4, the actual intake pressure PB is compared with the target value. If PB> target value, the routine proceeds to step 5, where the deceleration negative pressure correction amount BCV is reduced by a predetermined integral constant I. If PB <target value, the routine proceeds to step 6, where the deceleration negative pressure correction amount BCV is increased by a predetermined integration constant I. Steps 4 to 6 correspond to feedback control means.

Next, in step 7, the deceleration negative pressure correction amount BCV set by the feedback control is written and stored in a map on the RAM divided into grids by the engine speed N and the altitude ALT. Step 7 corresponds to a learning storage unit.

If it is not the learning condition, the process proceeds to step 8 and reads the deceleration negative pressure correction amount BCV written and stored in the map on the RAM divided into grids by the engine speed N and the altitude ALT, and reads the deceleration negative pressure correction amount BCV Set. Step 8 corresponds to learning control means.

Here, the deceleration negative pressure correction amount BCV is a duty ratio (%). When the duty ratio is set in this manner, a pulse signal of this duty ratio is applied to the valve opening coil of the auxiliary air control valve 5 during deceleration. Electricity is supplied, whereby the degree of opening is controlled, and a desired auxiliary air flow rate is obtained during deceleration.

In this embodiment, the intake pressure PB detected by the intake pressure sensor 10 is used assuming a so-called D-Jetro type in which the fuel injection amount is set based on the intake pressure PB. In a so-called L-Jetro system, which has an air flow meter and sets the fuel injection amount based on the intake air flow rate Q and the engine speed N, the basic fuel injection amount Tp = K · Q / N (K is a constant) may be used.

<Effects of the Invention> As described above, according to the present invention, the deceleration negative pressure correction function at the time of deceleration can be correctly maintained even if the auxiliary air control valve becomes dirty or the throttle valve becomes dirty. Thus, it is possible to prevent an increase in CO, HC, coasting afterburn, engine stall, increase in oil consumption, and the like.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, FIG. 2 is a system diagram showing one embodiment of the present invention, and FIGS. 3 and 4 are flowcharts showing control contents. 3 ... Throttle valve, 4 ... Auxiliary air passage, 5 ... Auxiliary air control valve, 6 ... Intake manifold, 7 ... Fuel injection valve, 8 ... Engine, 9 ... Control unit, 10 ...
Intake pressure sensor, 11… Rotation speed sensor, 12 …… Atmospheric pressure sensor

Claims (3)

(57) [Claims] An internal combustion engine having an auxiliary air control valve in an auxiliary air passage bypassing a throttle valve and controlling an intake air pressure in an intake manifold by controlling an auxiliary air flow rate through the auxiliary air control valve during deceleration. Feedback control means for performing feedback control on the auxiliary air flow rate so that the intake pressure during deceleration matches the target intake pressure under predetermined feedback control conditions, and learning for learning and storing the feedback control result. A deceleration control device for an internal combustion engine, comprising: storage means; and learning control means for controlling an auxiliary air flow rate using a learning result under conditions other than predetermined feedback control conditions. 2. The deceleration control device for an internal combustion engine according to claim 1, wherein the feedback control means sets the target intake pressure as at least the engine speed and the altitude as parameters. 3. The deceleration control device for an internal combustion engine according to claim 1, wherein the learning storage means learns the feedback control result using at least the engine speed and altitude as parameters.