JPH05312076A - Idling speed controller - Google Patents

Abstract

PURPOSE:To provide an idling speed controller that prevents any blow-up of useless engine speed and is excellent in convergeability to the desired idling speed, in an electronic control fuel injection system which controls idling speed feedback to the specified value. CONSTITUTION:This controller is provided with a means which detects a fact that a clutch is made into a state of being half-clutched, and when a drop in engine speed due to this half-clutchedness is detected, any renewal of an integral compensation value out of auxiliary air control is stopped, and a proportional compensation value is more increased than that of usual time as its constitution. With this constitution, since the integral compensation value is not increased in time of the engine speed drop, any blow-up of useless engine speed to be produced after disengaging the clutch is thus preventable in this way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle speed control device applied to an automobile engine having a clutch in a driving force transmission system from the engine.

[0002]

2. Description of the Related Art Among internal combustion engines such as a gasoline engine, especially in an engine for an automobile, it is indispensable to operate in an idle state. Therefore, the operating state in the idle state greatly affects the exhaust gas state and the fuel consumption. .. Therefore, an engine for an automobile has conventionally used an idle speed control device (ISC) that performs feedback control so that the idle speed of the engine converges to a predetermined target speed.

As the ISC, for example, when the throttle valve is fully closed and the clutch is in a predetermined state, various engine speeds such as the actual engine speed at that time and the engine temperature are used. The deviation from the target idle speed set on the basis of the parameter representing the state is detected, a control signal composed of the proportional component P and the integral component I is calculated in accordance with the deviation, and the throttle valve is bypassed by this control signal. It is generally known that the degree of opening of the auxiliary air valve is controlled to feedback control the engine to a predetermined target rotation speed. Note that the opening degree control of the auxiliary air valve at this time is performed by using a pulse (rectangular wave) drive signal and controlling the duty (referred to as control duty) of the drive signal. Target.

By the way, the control by the proportional component P and the integral component I is called PI control. This is divided into P control (proportional correction) and I control (integral correction), and the integral correction is
The correction amount is increased / decreased at regular intervals according to the rotational speed deviation, and the proportional correction is such that the correction amount is uniquely determined according to the rotational speed deviation.

These correction amounts are set based on the deviation between the engine speed and the target idle speed. Typical characteristics for this purpose are shown in FIGS. 2 and 3. In these figures, for example, if the deviation between the engine speed and the target idle speed is DLTRPM and this is -200 [rpm], in this case, the integral correction amount is 3 as shown in FIG. The value increases at a rate of [% / sec], and similarly, the proportional correction amount becomes a fixed value of 10% as shown in FIG.

Therefore, when the deviation between the engine speed and the target idle speed is kept at -200 [rpm], the drive signal supplied to the auxiliary air valve has 10
Fixed amount of [%] + increment of 3 [% / sec] is given,
As a result, the amount of air supplied to the engine is gradually increased, and the engine speed is controlled so as to converge to the target idle speed. As a conventional technique of this type, for example, the disclosure of JP-A-3-88939 can be cited.

[0007]

The prior art does not take into consideration that the clutch may be operated in a half-clutch state in an automobile having a clutch in the driving force transmission system. ISC, such as when driving in a traffic jam that starts and stops repeatedly
If the clutch is set to the half-clutch state while (idle speed control) is being performed, a load is applied to the engine, and the engine speed drops significantly below the target idle speed. Therefore, the correction amount is increased by feedback correction of the idle speed, but if the clutch pedal is fully depressed and the start work is stopped after that, the idle speed of the engine rapidly rises (blowing) by the increased correction amount.
As a result, there is a problem that the driver feels uncomfortable.

The mechanism of the sudden increase in the idle speed will be described in more detail.
FIG. 4 shows an example of the conditions for shifting to the feedback control of the idle speed. Since the shift to ISC is basically performed when the engine is in the idle state, this FIG. In other words, means for detecting that the engine is in the idle state is shown.

Here, in FIG. 4, gear SW is a switch that is turned on when the transmission (transmission) is in a neutral state, and clutch SW is clutch SW when the clutch is operated, that is, when the clutch pedal is depressed. It is a switch that turns on, but at this time, the gear SW turns on,
There is no particular problem with turning off, but clutch clutch O
There are some problems with N and OFF, as described below.

FIG. 5 shows ON / OFF operations of the clutch SW with respect to the stroke (depression amount) of the clutch pedal and the engagement state of the clutch. As is clear from this figure, when the clutch is operated, Even in the half-clutch state, the clutch SW is turned on, and as a result, as is apparent from FIG. 4, the feedback condition is satisfied and the ISC shifts.

Therefore, when the clutch is operated, the feedback condition is satisfied, and the ISC starts to work. At this time, when the clutch is put in the half-clutch state, the engine load increases and the rotation speed decreases. The problem as explained occurs. FIG. 6 shows the behavior of the engine speed and the change of the control duty of the drive signal supplied to the auxiliary air valve when the vehicle is started. When the clutch pedal is depressed, the clutch is depressed at time t ₁ . SW is O
When the engine speed reaches N, the ISC starts and the engine speed is controlled to converge to the target idle speed NREF. Then, by putting the gear of the transmission into the first speed, the gear SW is turned off at time t _2.
It becomes F.

After that, when the clutch pedal is gradually returned to the half-clutch state, when the time when the half-clutch state is reached is t ₃ , the engine is loaded from this point, so the engine speed becomes the target idle speed. It falls from NREF. Then, according to these deviations DLTRPM,
According to the characteristics shown in FIGS. 2 and 3, the control duty of the drive control signal of the auxiliary air valve increases as shown in the figure.

After that, if the clutch pedal is depressed and the clutch is completely released at time t ₄ ,
Here, the engine suddenly returns to the unloaded state, that is, the state before starting, and as a result, the engine speed also rapidly increases.
Therefore, after this time t ₄ , the control duty is decreased by the ISC in response to the rapid increase in the engine speed, but at this time, it is mainly the proportional correction amount that is decreased as shown in FIG. The integral correction amount will be lowered after a considerable delay.

As a result, the control duty of the drive signal to the auxiliary air valve is such that the engine speed is the target idle speed NREF.
Even when it coincides with the above, since it increases by the amount shown as an unnecessary amount in FIG. 6, thereafter, the engine speed further exceeds the target idle speed NREF, and therefore,
This makes the driver uncomfortable.

As a countermeasure against this, for example, the characteristic of the clutch SW shown in FIG. 5 is turned off even in the half-clutch state.
Therefore, in this case, the opening of the auxiliary air valve does not increase even if the engine speed decreases at the start. However, the engine stalls, which causes the driver further discomfort.

The object of the present invention is to sufficiently suppress the engine speed from rising even when the clutch is disengaged from the half-clutch state, and the convergence of the engine speed to the target idle speed by ISC is always sufficient. Another object of the present invention is to provide an idle speed control device that can be obtained.

[0017]

The above object is to provide means for detecting that the clutch in the power transmission system of the engine is in the half-clutch state, and when the half-clutch state is detected by this means, the ISC is used. This is achieved by stopping the calculation of the integral correction amount in the drive signal of the auxiliary air valve (holding the previous value).

Further, it is desirable that the proportional correction amount in the drive signal is further corrected and calculated so as to increase the deviation between the engine speed and the target idle speed.

[0019]

In the half-clutch state, the integral correction amount in the drive signal does not increase. Therefore, even if the clutch is subsequently released and the engine is in the no-load state, the increase in the engine speed is suppressed to the minimum and the ISC It is possible to sufficiently obtain the convergence of the engine speed to the target idle speed due to.

Further, by correcting the proportional correction amount so that the rotation speed deviation becomes large, the opening degree of the auxiliary air valve can be sufficiently widened with respect to the reduction of the engine rotation speed when the half clutch state is entered. The engine stall can be reliably suppressed.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The idle rotation control device according to the present invention will be described in detail below with reference to the illustrated embodiments. Figure 7
1 shows an example of an electronically controlled fuel injection device for an internal combustion engine for an automobile to which an embodiment of the present invention is applied, where 1 is an engine
(Internal combustion engine), 2 is an air cleaner, 3 is an air inlet, 4
Is an intake duct, 5 is a throttle body, 6 is a throttle valve, 7
Is an air flow meter (AFM) for measuring the intake flow rate, 8 is a throttle sensor, 9 is a surge tank, and 10 is an auxiliary air valve.
(ISC valve), 11 is intake manifold, 12
Is a fuel injection valve (injector), 13 is a fuel tank, 26
Is a fuel pump, 14 is a fuel damper, 15 is a fuel filter, 16 is a fuel pressure regulating valve (pressure regulator), 17
Is a cam angle sensor, 18 is an ignition coil, 19 is an igniter, 20 is a water temperature sensor, 21 is an exhaust manifold, 22
Is an oxygen sensor, 23 is a front catalyst, 24 is a main catalyst, 25 is a muffler, and 30 is a control unit.

Intake air of the engine 1 enters from the inlet portion 3 of the air cleaner 2, is taken into a surge tank 9 through an air flow meter 7 for detecting the intake air flow rate and a throttle valve 6 for controlling the air flow rate. Then, the air is the intake manifold 11 that directly communicates with each cylinder of the engine 1 here.
And is sucked into the cylinder of the engine 1. Then, a signal for detecting the intake air amount is output from the air flow meter 7 and input to the control unit 30.

On the other hand, the fuel in the fuel tank 13 is sucked and pressurized by the fuel pump 26, passes through the fuel damper 14 and the fuel filter 15, and is supplied to the fuel injection valve 12 provided in the intake manifold 11, and the control unit. Fuel is injected according to the injection signal from 30. At this time, the fuel pressure acting on the fuel injection valve 12 is regulated by the fuel pressure regulating valve 16. Therefore, the fuel pressure regulating valve 16 introduces the negative pressure of the intake manifold 11 and the fuel pressure and the intake manifold 11 are reduced. It works to keep the internal pressure difference constant.

Further, the throttle body 5 has a throttle valve 6
A throttle sensor 8 for detecting the opening of the throttle valve is attached, and a signal indicating the opening of the throttle valve is input to the control unit 30. Next, the ISC valve 10 is mounted so as to bypass the throttle valve 6, and a signal from the control unit 30 bypasses the throttle valve 6 to control the amount of air taken in and control the idle speed. Work.

Further, the cam angle sensor 17 generates a reference signal for detecting the engine speed, controlling the fuel injection timing, and the ignition timing, which is input to the control unit 30, and the water temperature sensor 20 outputs the reference signal. The temperature of the engine 1 is detected and this is also the control unit 30.
Entered in. Although not shown, the signal from the clutch SW mounted on the clutch pedal and the transmission
The signal from the gear SW attached to the (mission) and the signal from the vehicle speed sensor are also included in the control unit 30.
Entered in.

The control unit 30 calculates an optimum fuel amount according to signals from various sensors such as the air flow meter 7, the throttle sensor 8, the cam angle sensor 17, the water temperature sensor 20, that is, a signal representing the engine state, The fuel injection valve 12 is driven to supply fuel to the engine 1.
On the other hand, in the ignition control as well, the optimum ignition timing is similarly calculated, and a control signal is supplied to the igniter 19 to output the ignition coil 1
8 is energized to ignite.

On the other hand, in parallel with these controls, the control unit 30 further sends a drive signal to the ISC valve 10 in accordance with the states of the signals from the clutch SW, the gear SW and the vehicle speed sensor in addition to the engine state signal. Is supplied to start and stop ISC by feedback control according to the conditions shown in FIG.

Next, FIG. 8 shows an internal structure of the control unit 30 in one embodiment of the present invention.
MPU (Micro Processing Unit) 100
And RAM (random access memory) 101, RO
M (Read Only Memory) 102 and I / O
(Input / output circuit) LSI 103 includes buses 104 and 1 respectively
05 and 106 are connected so that data can be exchanged.

Then, the MPU 100 receives various signals representing the engine state from the I / OLSI 103 via the bus 106, sequentially calls the processing contents stored in the ROM 102, and performs a predetermined calculation, and the injector 12 and the igniter. 19, drive signals to various actuators such as ISC valve 10 are created and I / OL
Supply to each actuator via SI.

By the way, the present invention requires a means for detecting the half-clutch state. As an example of the means for detecting the half-clutch state, the stroke amount of the clutch pedal is converted into an electric signal to control unit 30. It is possible to input it to and detect the half-clutch position.
In this embodiment, the method of detecting the half-clutch state is used only by the internal processing of the control unit 30, and the half-clutch detection routine will be described below.

First, the half-clutch detection routine in this embodiment is a load variation determination routine shown in FIG. 9 for determining the presence or absence of a load acting on the engine, and a routine shown in FIG. It is divided into and.

The concept of the half clutch determination in this embodiment is that the engine speed decreases when a load is applied. At this time, if the engine speed does not increase even though the auxiliary air amount is increased. Since it indicates that a load is applied, this is used to detect the half-clutch state. The auxiliary air control routine after detecting the half-clutch state is as shown in FIG.

Each control routine will be described below. First, the load fluctuation determination routine of FIG. 9 will be described. First, in step 1000, the engine speed NDATA is read, in step 1001, the target value NREF of the idle speed is read, and in step 1002, the load fluctuation determination speed LDRPM is read. ..

Subsequently, at step 1003, the load determination flag is checked, and if #LDCHK indicating the flag is 0, the process proceeds to step 1004. This step 1004 is a process for checking whether or not the amount of engine rotation drop due to the load is equal to or greater than a predetermined value. If the actual engine speed NDATA is lower than the predetermined value, the process proceeds to step 1005 and the load determination flag #LDCHK is set to 1 To Next, the auxiliary air correction amounts ISCI and ISCP are stored as TISC to detect whether or not the clutch is in the half-clutch state.
The present rotational speed NDATA is stored as OFSRPM, and then this routine ends. On the other hand, when the result of step 1004 is NO, it is determined that the amount of decrease in the number of revolutions does not correspond to the load due to the half-clutch state, and this routine is ended as it is.

The result of step 1003 is YES.
When it becomes, it progresses to step 1007. In this step 1007, the actual engine speed NDATA is compared with the target speed NREF. If NDATA is greater than NREF, it means that the load has been disconnected, so the routine proceeds to step 1008, where the load determination flag #LDC.
Set HK to 0 and half clutch mode determination flag #PC
Also set LTMOD to 0. Then, at step 1009, T
Clear ISC and OFSRPM to 0. In addition, these half-clutch mode determination flags #PCLTMOD and TI
The SC and OFSPRM will be described later in detail with reference to FIG.

FIG. 10 shows an example of the half-clutch mode determination routine. In step 1100, the half-clutch mode determination flag #PCLTMOD is checked. This flag #PCLTMOD is set to 1 in the half-clutch state, so if this flag is 1, this routine ends.

Therefore, when the flag #PCLTMOD is 0, the process proceeds to step 1101 and subsequent steps to determine the half-clutch state. First, in step 1101, the load determination flag is checked, and if it is 0 (NO),
This routine ends here. On the other hand, when the load determination flag is 1 (YES), the routine proceeds to step 1102, where the change amount of the auxiliary air control amount after the load determination flag #LDCHK becomes 1 is stored and stored as DLTISC.
Next, the processing proceeds to step 1103, and the load determination flag #LDC
Obtain the engine speed change amount after HK becomes 1, and
Store as LTRPM.

Next, the auxiliary air control change amount DLTIS
In step 1104, the determination area is searched using C and the engine speed change amount DLTRPM. As shown in FIG. 11, this determination area is divided into three types of areas A, B, and C in advance.
Will increase the DLTSC if the DLTSC increases.
This shows a region where the RPM increases steadily, which is a region that means the engine state when the load is small. On the other hand, in the area C, even if DLTISC increases, DLTRP
In a region where M does not increase, the load is extremely heavy, which corresponds to a so-called half-clutch. The area B is located between the areas A and C and means an area in which it is not clearly determined whether or not the clutch is in the half-clutch state.

After the judgment area is searched in step 1104, the process proceeds to step 1105 and the result here is YE.
If S, this routine is ended. If NO, the process proceeds to step 1106. And the result here is N
If it is O, it means that the state is in the region C, and therefore the processing proceeds to step 1110, and the half clutch mode determination flag #PCL
The TMOD is set to 1 and this routine ends.

On the other hand, the result of step 1106 is YSE.
If so, the process proceeds to step 1107 to confirm the half-clutch mode. This is a routine for determining that the clutch is in the half-clutch mode even when it is determined to be in the region B when the state is present for a predetermined time or longer. First, the result in step 1107 is In the case of YES, the timer BMODTM is first incremented in step 1108, and then the elapsed time is determined in step 1109. If the result is YES, step 1110 is executed.
However, if the result is NO, this routine ends here.

Therefore, in this embodiment, even if it is not clearly determined whether the clutch is in the half-clutch state or not, if this state continues for a predetermined time or longer, the half-clutch state is determined. It is designed to judge. On the other hand, when the result of step 1107 is NO, the process proceeds to step 1111 and the timer BMODTM
To clear the routine.

Next, FIG. 12 shows a control routine as an example of the auxiliary air correction control after detecting the half-clutch state in this embodiment. First, step 1200.
At step 1201, the current engine speed NDATA is read, at step 1201 the target speed NREF is read, and at step 1202, the engine speed deviation DEFRMP necessary for performing closed loop control is calculated. Then, step 1203
Then, the half-clutch mode determination flag #PCLTMOD is checked. If the result is NO, then normal control is performed. That is, first, at step 1205, the proportional correction amount is retrieved from the characteristics shown in FIG. 3 by the rotation speed deviation DEFRMP. Next, in step 1206, since the determination is also NO at this time, step 1207
Then, after the integral correction amount is retrieved from the characteristic shown in FIG. 2 by the rotational speed deviation DEFRPM, the present routine is ended.

On the other hand, if the result is YES in step 1203, the flow proceeds to step 1204, and the rotation speed deviation DEFRP
Modify M. The correction at this time is performed by the following equation.

DEFRPM1 = DEFRPM−K × DEFRPM where DEFRPM1: rotational speed deviation after correction DEFRPM: rotational speed deviation K: correction rate This DEFRM takes a negative value, which is a negative value. As a result, in step 1205, when the proportional correction amount is searched from the characteristics of FIG. 3, the search value is set to a large value.

Next, since the result of step 1206 is YES, at this time the routine ends without updating the integral correction amount. Therefore, the contents of the ISC control in this embodiment are as shown in FIG. Next, the operation obtained by this embodiment will be described with reference to FIG.

As in the case of the conventional example of FIG. 6, if the half-clutch mode determination flag #PCLTMOD is set to 1 by the routine of FIG. 10 at a certain time point after time t ₃ , in this embodiment, As shown in FIG. 13, the condition is met, and steps 1204 and 12 of FIG.
By the processing of 05, a large value of the proportional correction amount is given when this condition is satisfied, so that the control duty is greatly raised, whereby the ISC valve 10 is responsive to a drop in the engine speed due to an increase in the engine load due to the half-clutch. The increase in the degree of opening follows, and therefore, according to this embodiment, the risk of engine stall can be sufficiently suppressed.

On the other hand, in this embodiment, the result of step 1206 in FIG. 12 is YES because the same condition is satisfied.
Therefore, from this point in time, the calculation processing of the integral correction amount in step 1207 is skipped, and the calculation of the integral correction amount is stopped. Therefore, as shown in FIG. since it is held at the value immediately preceding this point, then, as in the prior art of FIG. 6, depressing the clutch pedal, even when fully open the clutch at time t _4, in this case, FIG. 1
As shown in FIG. 3, the integral correction amount in the control duty is not increased, and is maintained at substantially the same value as at time t ₃ before the clutch is put in the half-clutch state. Since it has not been greatly increased as in the case
Time t ₄ after quickly converges to the target idle speed NREF as proportional compensation amount by the action of ISC goes is reduced, as in the prior art of FIG. 6, the rotational speed of the engine is rapidly increased (blow-up) The driver will not feel uncomfortable.

Therefore, according to this embodiment, the abnormal increase of the engine speed can be surely suppressed, the convergence of the ISC can be sufficiently obtained, and the risk of the engine stall can be sufficiently suppressed.

[0049]

According to the present invention, during the operation of the ISC, when the clutch is operated to the half-clutch state and the engine speed decreases, the updating of the integral correction amount in the auxiliary air amount control is stopped. Therefore, even if the clutch is disengaged and there is no load after that, it is possible to prevent the engine speed from rising abnormally and to supply air by forcibly increasing the proportional correction amount when the engine speed drops. As a result, engine stalling (engine stall) can be prevented and a comfortable driving state can be easily maintained.

[Brief description of drawings]

FIG. 1 is a control block diagram of an embodiment of an idle speed control device according to the present invention.

FIG. 2 is a characteristic diagram showing an example of integral correction amount calculation characteristics in feedback control of idle speed.

FIG. 3 is a characteristic diagram illustrating an example of a proportional correction amount calculation characteristic in feedback control of idle speed.

FIG. 4 is a logic diagram showing an example of a feedback start condition in the idle speed control device.

FIG. 5 is an explanatory diagram showing a clutch engagement state and a clutch SW operation state with respect to a depression amount of a clutch pedal.

FIG. 6 is an explanatory diagram showing a defect example of a conventional technique of an idle speed control device.

FIG. 7 is a configuration diagram showing an electronically controlled fuel injection device for an internal combustion engine for a vehicle, to which an embodiment of an idle speed control device according to the present invention is applied.

FIG. 8 is a block diagram of a control unit according to an embodiment of the present invention.

FIG. 9 is a flowchart for explaining the operation of the embodiment of the present invention.

FIG. 10 is a flowchart for explaining the operation of the embodiment of the present invention.

FIG. 11 is an explanatory diagram showing a half-clutch mode determination area used as one means for detecting a half-clutch state in the embodiment of the present invention.

FIG. 12 is a flow chart for explaining the operation of the embodiment of the present invention.

FIG. 13 is an explanatory diagram showing the operation of the embodiment of the present invention.

[Explanation of symbols]

 1 Engine (Internal Combustion Engine) 2 Air Cleaner 3 Air Inlet 4 Intake Duct 5 Throttle Body 6 Throttle Valve 7 Air Flow Meter (AFM) 8 Throttle Sensor 9 Surge Tank 10 Auxiliary Air Valve (ISC Valve) 11 Intake Manifold 12 Fuel Injection Valve (Injector) 13 Fuel Tank 14 Fuel Damper 15 Fuel Filter 16 Fuel Pressure Regulator (Pressure Regulator) 17 Cam Angle Sensor 18 Ignition Coil 19 Igniter 20 Water Temperature Sensor 21 Exhaust Manifold 22 Oxygen Sensor 23 Front Catalyst 24 Main Catalyst 25 Muffler -26 Fuel pump 30 Control unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location F02M 69/32 F02D 41/08 315 7813-3G 45/00 362 J 7536-3G

Claims (3)

[Claims] 1. An idle speed control device for an internal combustion engine for an automobile, wherein the opening degree of an air valve that bypasses a throttle valve is proportional-integrally controlled according to the rotation speed of the internal combustion engine, and the rotation speed of the internal combustion engine is feedback-controlled. Providing a half-clutch detection means for detecting that the clutch included in the driving force transmission system of the internal combustion engine is in the half-clutch state, and when the half-clutch state is detected by the half-clutch detection means, the proportional-plus-integral control An idle speed control device characterized by being configured to stop the calculation of the integral correction amount in. 2. The invention according to claim 1, wherein, when the half-clutch state is detected by the half-clutch detection means, the rotational speed of the internal combustion engine at that time and the target idle speed are proportional to the proportional-integral control. And a predetermined value calculated according to the deviation from the above. The idle speed control device is characterized by being added. 3. The invention according to claim 1, wherein the half-clutch detection means detects that the clutch is in a half-clutch state based on a change amount of a rotation speed of the internal combustion engine with respect to a change amount of the opening degree of the air valve. And an idle speed control device.