JPH11166436A - Method for controlling isc valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of the controllability of an ISC valve by estimating the valve opening degree of the ISC valve from an engine running state, calculating an estimated step value and learning that a step value outputted to a stepping motor is an estimated step value. SOLUTION: When an engine is in a warmed state, estimation learning control is performed for the valve opening degree of an ISC valve 42 for controlling a target idling rotational speed. In other words, if an idling state satisfies a certain condition, a step value recognized by the ISC valve control part 77 of an ECU 74 is rewritten to an estimated step value set beforehand according to an engine running state, and learning is performed to recognize that the currently recognized step value is an estimated step value. The estimated step value is set by referring to a data table having a step value preset according to an idling rotational speed stored in a ROM 74d, and the set estimated step value is corrected according to an engine load.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ISC valve and, more particularly, to an ISC valve which is opened and closed by a stepping motor.
The present invention relates to a valve control method.

[0002]

2. Description of the Related Art Conventionally, in an intake system of an engine, an idle speed control (hereinafter, referred to as an idle speed control) which adjusts and maintains an idle speed to a target idle speed set according to an engine operating state such as an engine water temperature and an engine load. (Referred to simply as "ISC"). Some ISC valves open and close using a stepping motor as an actuator.

[0003] The stepping motor is rotated by a control pulse signal from the ISC valve control unit, and stops at the energized phase position designated as a step value by the control pulse signal.
The valve opening of the SC valve is configured to be variably controlled. Therefore, the flow rate of the passing air passing through the ISC passage can be increased or decreased and the idle speed can be accurately controlled.

However, the stepping motor may cause a so-called misstep, in which a rotation operation is not performed according to an instruction of the ISC valve control unit due to an excessive load, noise, or the like. When this misstep occurs,
The ISC valve control unit cannot accurately recognize the opening position of the valve unit.

Therefore, there is a possibility that a deviation may occur between the step value of the stepping motor recognized by the ISC valve control unit and the actual valve opening of the valve unit, which is the actual step value of the stepping motor. This deviation deteriorates the controllability of the idle speed control by the ISC valve.

Various methods have heretofore been proposed to prevent such a deviation and to correct such a deviation if it occurs. For example,
As a method of correcting the deviation when it occurs, a pressing origin detection control for forcibly correcting the deviation by pressing the valve portion against a valve seat or the like is generally used. As a result, the valve opening of the valve unit recognized by the ISC valve control unit from the step position of the stepping motor matches the actual valve opening, and the accuracy of the correspondence between the two is ensured.

When the origin detection control is performed during operation of the engine to forcibly move the ISC valve, the amount of intake air changes irrespective of the operator's intention and affects the engine output. Idle stability as a result,
This is performed after the engine is stopped, which does not affect the running performance of the vehicle.

[0008]

However, the above-described initialization processing cannot be performed unless the operation of the engine is stopped. Therefore, when the operation state of the engine is long, or when an excessive load is applied to the stepping motor, the stepping motor may not rotate according to the control command of the control unit, that is, a so-called misstep may occur. If the miss step occurs frequently during the operation of the engine, the deviation is gradually accumulated, and a large deviation may occur. Such a large deviation has a problem in that the controllability of the idle speed by the ISC valve is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to compare the actual valve opening of an ISC with the valve opening recognized by an ISC valve control unit during engine operation. It is an object of the present invention to provide a method of controlling an ISC valve which can prevent the occurrence of a deviation and its cumulative expansion to prevent the controllability of the ISC valve from deteriorating.

[0010]

According to a first aspect of the present invention, there is provided a method for controlling an ISC valve, comprising: estimating a valve opening of an ISC valve from an engine operating state; The method is characterized in that an estimated step value corresponding to the opening is calculated, and that the step value output to the stepping motor is learned as the estimated step value.

According to this, during the idling operation of the engine, the step value output to the stepping motor is determined by the actual ISC estimated from the operating state of the engine.
It is rewritten to the estimated step value corresponding to the valve opening of the valve, and it is learned that the estimated step value has been output to the stepping motor.

Therefore, if there is a deviation between the step value output to the stepping motor and the actual valve opening of the ISC valve due to a misstep of the stepping motor or the like, the deviation is corrected. can do. As a result, it is possible to prevent the controllability of the ISC valve from deteriorating due to the cumulative increase of the deviation during the operation of the engine.

Here, the estimated step value is a value obtained by estimating the valve opening of the ISC valve from the operating state of the engine in a standard state, and obtaining a step value corresponding to the estimated valve opening by an empirical value. Is set in advance.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory view of the overall configuration of an engine device provided with an ISC valve to which the control method according to the present invention is applied. The engine in the present embodiment is an automobile engine, for example, a horizontally opposed engine 10, and as shown, an intake passage 12 and an exhaust passage 14 communicate with each other.

The intake chamber 1 is located upstream of the intake passage 12.
6 is opened in front of the vehicle body (not shown), and an intake pipe 22 branched from a surge tank 20 communicates with a downstream side of the intake passage 12.
Through each of the combustion chambers 26. On the other hand, a downstream side of the exhaust passage 14 is connected to a muffler 28 attached to a rear portion of the vehicle body, and an exhaust pipe 32 communicating with each combustion chamber 26 via each exhaust port 30 is connected to an upstream side of the exhaust passage 14. I have.

In the intake passage 12, in order from the upstream side,
An air cleaner 34 for removing dust in the air, an air flow meter 36 for detecting the intake air amount Q, and a throttle valve 38 for controlling the intake air amount Q are provided. The throttle valve 38 is provided with a throttle opening sensor 39 for detecting the throttle opening θ.

The intake passage 12 is provided with an ISC passage 40 that bypasses the throttle valve 38, and an ISC valve 42 for adjusting the intake air amount during idling is provided in the middle of the ISC passage 40. ing. The ISC valve 42 uses, as an actuator, a stepping motor 43 that controls the valve opening of the valve unit of the ISC valve 42 by a step value output as a control pulse signal from an ISC valve control unit described later.

The injector 44 is located downstream of the intake pipe 22.
Are provided to face the intake port 24, and each of these injectors 44 is connected to a fuel pipe 48 from a fuel pump 46.
Is atomized and injected through the fuel pumped through the nozzle.

On the other hand, a catalyst 50 such as a three-way catalyst for purifying the exhaust gas is interposed in the exhaust passage 14 near the engine body 10, and an oxygen concentration in the exhaust gas is provided upstream of the catalyst 50. the air-fuel ratio of the mixture detected by detecting, O ₂ sensor 52 outputs the boundary of the stoichiometric air-fuel ratio has a Z characteristic is provided.

The neutral switch 72 is a switch for detecting when the position of the shift lever of the automatic transmission is in the neutral position (N), and functions as a neutral state detecting means.
Thus, the presence or absence of the torque converter load applied to the engine is detected.

The air conditioner switch 73 is a switch for detecting ON / OFF of a compressor of the air conditioner, and detects presence or absence of a compressor load of the air conditioner.

In this figure, reference numeral 66 denotes a crank angle sensor for detecting a crank angle and an engine speed Ne;
0 denotes a water temperature sensor for detecting the temperature of the cooling water, and 71 denotes a vehicle speed sensor for detecting the traveling speed. In addition, description of members shown in this drawing that do not directly relate to the function of the present invention will be omitted.

An electronic control unit (hereinafter simply referred to as "ECU") 74 for controlling the driving of the above members and inputting a detection signal from each sensor will be described below with reference to FIG. As shown, the ECU 74 includes an input interface 74a for inputting a signal from each sensor and an output interface 7 for outputting a drive control signal to each member.
4b, a CPU 74c as a main processing unit, a ROM 74 for storing a control program and preset fixed data
d, a RAM 74e for storing input signals from various sensors and various data for performing arithmetic processing, a backup RAM 74f for storing learning data and the like, and a timer 74
g and the like are connected to each other by a bus line 74h.

An input interface 74a of the ECU 74 includes a water temperature sensor 7 as an engine operating state detecting means.
0, neutral switch 72, crank angle sensor 6
6. Each signal path of the air flow meter 36 is connected, and the ISC valve 4 is connected to the output interface 74b.
Two signal paths are connected.

The ECU 74 has, as its internal functions, a target idle speed setting section 75 for setting a target idle speed Nt, which is an idle speed according to the engine operating state, and the stepping motor 4 of the ISC valve 42.
The control amount calculation unit 76 calculates the control amount of No. 3 and an ISC valve control unit 77 that controls the ISC valve 42 based on the control amount.

The target idle speed setting section 75 is provided with an opening degree of the throttle valve 38, an engine load, and a water temperature sensor 70.
The engine operating state is detected using the cooling water temperature Tw according to the above, and the target idle speed Nt according to the engine operating state is detected.
At this time, a target idle speed Nt is set in consideration of the state of the compressor load detected by the air conditioner switch 73 and the state of the torque converter load by the neutral switch 72, and outputs the target idle speed Nt to the control amount calculation unit 76.

The control amount calculation unit 76 includes the crank angle sensor 6
The control amount for controlling the stepping motor 43 is calculated by inputting the engine speed Ne and the target idle speed Nt calculated from the detection signal of No. 6 and comparing them.

The ISC valve control unit 77 includes a vehicle speed sensor 7
It is determined from the vehicle speed v and the opening .theta. Of the throttle valve 38 whether the engine operating state is idling or not. To control the ISC valve 42.

That is, the ISC valve control unit 77
The step value is output to the stepping motor 43 of the SC valve 42 by the control pulse signal, and the stepping motor is rotated to the energized phase position corresponding to the step value and stopped at that position. As a result, the opening degree of the ISC valve 42 is changed, the intake air amount is adjusted, and the idle speed is controlled.

Next, a method of controlling the ISC valve provided in the engine device having the above configuration will be described below. FIG. 3 is a flowchart illustrating a control routine of the ISC valve according to the embodiment.

In the control method of the ISC valve according to the present embodiment, as shown, two types of control are performed according to the idling state of the engine. One is a normal ISC control based on the engine operating state such as the engine water temperature, and the other is an ISC valve estimation learning control.

First, in S1 and S2, it is determined whether or not the idling state of the engine satisfies a predetermined condition. In S1, the engine speed is 6
It is determined whether it is between 00 rpm and 700 rpm,
When the condition is satisfied (YES), the process proceeds to S2, and when the condition is not satisfied (NO), the normal ISC control is performed and S4 is performed.
Move to.

In S2, it is determined whether the water temperature is higher than 80 ° C. If it is determined that the water temperature is higher than 80 ° C. (YES),
When it is determined that the engine operation state is the state where the warm-up operation has been completed, the process shifts to S3, and when the temperature is equal to or lower than 80 ° C. (NO)
Moves to S4 in order to perform the normal ISC control assuming that the warm-up operation is being performed.

At S4, normal control of the ISC valve 42 is performed. That is, depending on the operating state of the engine, IS
When the valve opening of the C valve 42 is set, a step value for changing the valve portion from the current valve opening to the target valve opening is output from the ISC valve control unit 77 to the stepping motor 43. Is done.

Here, for example, the ISC valve control unit 77
When the current step value recognized by the controller is 60 steps and the idling rotational speed is 630 rpm, it is changed to 650 rpm.
When controlling to m, the step value for increasing the idle speed by 20 rpm in 60 steps is output from the ISC valve control unit 77 to the stepping motor 43. Thus, the stepping motor 43 rotates to the energized phase position corresponding to the step value and stops.

As described above, in the ordinary control of the ISC valve 42, the step value output from the ISC valve control unit 77 to the stepping motor 43 and the actual valve position of the ISC valve 42 correspond exactly. The valve opening is controlled based on the step value recognized by the ISC valve control unit 77.

On the other hand, in S3, estimation learning control of the valve opening of the ISC valve 43 is performed. This learning control of estimating the valve opening means that when the idling state satisfies a certain condition, the step value recognized by the ISC valve control unit 77 is changed to an estimated step value set in advance according to the engine operating state. This is control for rewriting and learning that the currently recognized step value is an estimated step value.

That is, when the idling state of the engine is in a preset standard state, the current IS
Assuming that the valve opening of the C valve is a predetermined opening,
Regardless of how the step value is recognized by the ISC valve control unit, the step value recognized by the ISC valve control unit is learned as the estimated step value. Therefore, when the step value recognized by the ISC valve control unit deviates from the actual step value, that is, the opening degree of the valve unit, this can be corrected.

FIG. 4 is a flowchart showing an estimation step value calculation routine for calculating an estimation step value for estimating the valve opening of the valve section used in S3. First, in S11, an estimated step value in a normal engine operating state is set. Here, the estimated step value is set by referring to a data table stored in the ROM 74d of the ECU 74 and in which a step value corresponding to the idle speed is set in advance.

After S12, an estimated step value obtained by correcting the estimated step value set in S11 according to the engine load is calculated. As a result, the step value recognized by the ISC valve control unit and the actual step value, that is, the opening degree of the valve unit, can be accurately matched, and the deviation can be corrected more accurately.

At S12, the neutral switch is turned on.
/ OFF determines whether a torque converter load is applied to the engine. If the neutral switch is OFF (YES), it is determined that the gear position is in the drive position and a torque converter load is applied to the engine, and the process proceeds to S13 in order to correct a decrease in engine speed due to the torque converter load. I do. In S13, an estimated step value in which the torque converter load is corrected is calculated.
When the neutral switch is ON in S12 (NO), the gear position is in the neutral position, and no torque converter load is applied to the engine.
Since there is no need to correct the estimated step value due to the torque converter load, the process proceeds to S14 without correcting the estimated step value in S13.

In S14, the air conditioner switch is turned ON / O.
The FF determines whether a compressor load is applied to the engine. If the air conditioner switch is ON (YES), it is determined that the compressor of the air conditioner is being driven by the engine and the compressor load is being applied to the engine. Then, the process proceeds to S15 in order to correct the decrease in the engine speed due to the compressor load.

In step S15, an estimated step value is calculated by correcting the estimated step value set in step S11 or S13 by a decrease in the engine speed due to the compressor load. Then, the process exits from this routine (end).
When the air conditioner switch is OFF in S14 (NO), since the compressor load is not applied, it is not necessary to correct the estimated step value by the torque converter load, and the estimated step value is not corrected in S15. Exit this routine at the end (end).

Then, the ISC valve is controlled based on the step value learned as described above.

Therefore, the step value recognized by the ISC valve control section can be adjusted to the actual step value, that is, the opening of the valve section. If a deviation occurs during the operation of the engine, this deviation is corrected. be able to.
As a result, it is possible to prevent the controllability of the ISC valve from deteriorating due to the accumulation of the deviation even in the continuous operation for a long time.

Further, after the engine is stopped, there is no need to perform an initialization process for matching the step position of the stepping motor with the actual opening of the valve portion, which is the actual step position of the stepping motor, and the ignition O
All electric systems can be stopped simultaneously with the FF.

[0048]

As described above, the IS according to the present invention is
According to the control method of the C-valve, the step value outputted to the stepping motor is controlled to be learned as the estimated step value set in advance according to the operating state of the engine. The occurrence of a deviation from the opening and the cumulative expansion thereof can be prevented,
Deterioration of controllability of the ISC valve can be prevented.

As a result, it is possible to prevent the controllability of the ISC valve from deteriorating even during continuous operation for a long time.
The idle speed can be controlled by controlling the appropriate ISC valve.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an engine to which an ISC valve control method according to the present invention is applied.

FIG. 2 is a schematic explanatory diagram of an ECU.

FIG. 3 is a flowchart showing a control routine of the ISC valve according to the embodiment;

FIG. 4 is a flowchart illustrating an estimation step value calculation routine for calculating an estimation step value for estimating a valve opening of a valve unit.

[Explanation of symbols]

 42 ISC valve 43 Stepping motor 75 Target idle speed setting unit 76 Control amount calculation unit 77 ISC valve control unit

Claims (1)

[Claims] 1. A target idle speed corresponding to an operating state of an engine, comprising: a valve portion for adjusting an intake air amount during an idle operation of the engine; and a stepping motor as an actuator for driving the valve portion. In the control method of the ISC valve, the valve opening of the ISC valve is estimated from the operating state of the engine, an estimated step value corresponding to the estimated valve opening is calculated, and the step value output to the stepping motor is calculated as follows. Learning the estimated step value.
Control method of C valve.