JPH0684732B2 - Engine idle speed controller - Google Patents

Description

TECHNICAL FIELD The present invention relates to an engine idle speed control device having a learning control function.

(Prior Art) An idle speed control device by electronic control, which is widely used in automobile engines in recent years, generally forms a bypass passage for intake air so as to bypass a throttle valve of an engine, and a throttle valve in this bypass passage. Is provided with an air amount adjusting means (solenoid valve) for adjusting the intake air amount in the minimum opening state (idle state) of the engine, depending on the deviation amount between the actual engine speed and the set target speed. The air amount adjusting means is feedback-controlled to operate at the idle target speed.

Then, in the above case, specifically, using an engine controller configured by a microprocessor, the intake air amount adjusting means is controlled by a predetermined basic control amount set corresponding to the target rotation speed, When the actual rotation speed obtained by the predetermined basic control amount does not match the target rotation speed, the actual rotation speed is corrected by correcting the predetermined basic control amount according to the load amount or the deviation amount at that time. A configuration is adopted in which the target rotation speed is converged.

By the way, the final control amount including the correction amount is generally determined as follows.

Final control amount G = G _B + Σ G _L + G _FB However, G _B : Basic control amount G _L : Correction amount corresponding to various engine loads G _FB : Feedback correction amount Here, the above basic control amount G _B is when there is no load. It is set corresponding to the engine speed and the cooling water temperature based on the characteristic value peculiar to the engine. Further, the correction amount G _L corresponding to the engine load (for example, air conditioner, power steering, etc.) is set as an eigenvalue corresponding to each load amount. Then, it acts as the intake air amount increase value by the open loop control. Further, the feedback correction amount G _FB is a correction amount at the time of closed loop control, which is arbitrarily determined according to the operating state according to the deviation amount between the actual engine speed and the target speed.

That is, as is clear from the above general formula (for example, the duty ratio calculation formula), the final control amount G
Is centered around the basic control amount G _B determined by the engine-specific characteristic value and the cooling water temperature, and the correction amount corresponding to the load amount and the correction amount corresponding to the deviation amount of the rotational speed are added. In this case, of course, the basic control amount is the largest as the control amount.

Therefore, in order to control the engine speed at the time of idling with high accuracy, it is premised that the value of the basic control amount G _B at the time of no load is set to the highest possible accuracy.

However, the engine structure, shape, parts, seal state, etc. that determine the characteristic value peculiar to the engine cannot be always considered as a completely fixed value because they change over time. Also, the above characteristic values are the engine usage environment (low and highlands).
It also fluctuates due to changes in atmospheric pressure due to differences in. Therefore, the deviation amount between the actual engine speed and the originally required target speed when only the basic control amount corresponding to the characteristic value of the engine is conventionally detected as the feedback amount by the negative feedback action during the feedback correction, There has been proposed an engine idle speed control device equipped with a learning correction means for learning and storing the detected value as a correction value for the basic control amount itself (see, for example, JP-A-56-44431). According to such an engine idle speed control device, the general formula for calculating the final control amount G is modified as follows.

G = G _B + G _S + ΣG _L + G _FB However, G _S : learning correction term Therefore, according to such a configuration, even if the engine characteristic value fluctuates due to the secular change of the engine or the difference in the operating environment, As a result, the basic control amount itself is automatically corrected, so that it is possible to obtain the effect of free engine maintenance and improve the setting accuracy of the basic control amount.

However, in that case, in order to actually determine and store the correction value at the time of the learning correction, as is apparent from the above description, the operating state of the engine is in a learnable state, that is, no load and steady state. It is necessary to be. Therefore, the learning correction cannot be performed under various engine loads, for example, when the air conditioner and the power steering are operating. In this case, when the engine load is one that can easily detect the load application state such as an air conditioner or a power steering as described above, a malfunction can be easily prevented by prohibiting the learning correction operation at the time of detection. be able to.

However, in the case of the operation of various electric loads where the alternator becomes the engine load, there are many types first, and then it is difficult to grasp the ON / OFF state in relation to the engine. Due to the fact that the amount of power generation does not correspond only to load operation and is greatly affected by the state of charge of the battery, the operating state cannot be easily detected, and it is difficult to specify the load amount. Therefore, there has been a certain limit to improving the accuracy of the learning correction control according to the above-mentioned conventional technique.

(Object of the Invention) The present invention has been made based on the above circumstances, and at the time of learning correction, by fixing the field current of the alternator to a predetermined value, the load amount is fixed to a constant value, and a higher precision is achieved. An object of the present invention is to provide an idle speed control device for an engine that enables learning correction control.

(Means for Achieving the Object) In order to achieve the above object, the present invention provides a target rotation speed setting means for setting a target rotation speed of an engine under no load, and an actual rotation speed of the engine under no load. Is set to the target speed, the basic control amount setting means for setting the basic control amount for the engine, the actual speed of the engine obtained by the basic control amount set by the basic control amount setting means, and the target rotation speed. Correction amount calculation means for calculating a correction amount for matching the actual rotation speed of the engine with the target rotation speed based on the amount of deviation from the engine speed, and the correction amount calculated by the correction amount calculation means for the basic control. Learning correction means for storing and updating at a predetermined calculation cycle as a correction value for the basic control amount set by the amount setting means, and for correcting the basic control amount with the stored and updated value. In an engine idle speed control device including: an alternator control means for maintaining a field current of an alternator driven by the engine at a predetermined value when the learning correction means is activated, regardless of a change in an electric load. Is.

(Operation) According to the above means, the field current of the alternator is maintained at a predetermined value when the learning correction means is activated, regardless of changes in various electric loads, so the alternator as an engine load is defined as a fixed value without load fluctuation. Therefore, it is possible to estimate as a value peculiar to the engine when determining the basic control amount in the learning correction control. As a result, no matter how the various electric loads or the battery voltage itself changes, the learning correction control value is not affected at all, and the learning accuracy is further improved.

(Embodiment) First, FIG. 2 and FIG. 3 show an idle speed control device for an engine according to an embodiment of the present invention, and FIG. 2 is a schematic diagram of a control system for the above embodiment device, FIG. 3 is a flow chart for explaining the operation of the above-mentioned embodiment apparatus, and FIG. 4 is a throttle valve opening (TVO) and engine speed (rpm) for explaining the control operation in the above-mentioned embodiment apparatus.
It is a characteristic graph which shows the relationship with.

First, an outline of the control system of the embodiment of the present invention will be first described with reference to FIG.

In FIG. 2, reference numeral 1 is an engine body, intake air is sucked from the outside through an air cleaner, and then supplied to each cylinder through an air flow meter 2 and a throttle chamber 3, and fuel is supplied to an engine control unit 9 which will be described later. It is designed to be injected by a fuel injector 5 controlled by. The amount of intake air to the cylinder is determined by the throttle chamber 3
It is controlled by the throttle valve 6 provided inside,
The amount is detected by the air flow meter 2. The throttle valve 6 is operated in conjunction with the accelerator pedal, and is maintained at the minimum opening state in the idle operation state.

On the other hand, the throttle chamber 3 is provided with a bypass passage 7 that bypasses the throttle valve 6.
The bypass passage 7 is provided with a solenoid valve (throttle valve) 8 that serves as an air amount adjusting means for controlling the engine speed during idling. Therefore, in the idle operation state, the intake air that has passed through the air flow meter 2 has the bypass path 7
Will be supplied to each cylinder via the, and the amount of supply will be adjusted by the solenoid valve 8. This solenoid valve 8
The open / closed state is controlled by the duty ratio of a control pulse signal (hereinafter, simply referred to as a control signal) G supplied from an engine control unit (hereinafter abbreviated as ECU) 9. Further, reference numeral 15 is an alternator driven by an engine, and the amount of power generation is an IC regulator.
Controlled by 14. IC regulator 14
While changing the field current of the alternator 15 controls the amount of power generation of the alternator 15, its operating state is controlled by the control signal from the ECU 9. Further, reference numeral 12 is a fuel tank, 13
Indicates a fuel supply pump.

The ECU 9 is mainly composed of, for example, a microprocessor (CPU), and includes a memory (ROM and RAM) and an interface (I / O) circuit. And this ECU
The interface circuit 9 includes, for example, an engine start signal S, an engine speed detection signal N, a cooling water temperature detection signal T _{W of} the engine body 1 detected by a thermistor,
For example, the opening signal TVO of the throttle valve 6 detected by the potentiometer, the intake air amount detection signal Q detected by the air flow meter 2, various load signals L of the air conditioner, the power steering, etc. are input.

Reference numeral 10 indicates an exhaust pipe provided with a three-way catalytic converter 11.

Next, the control operation of the above control device will be described in detail with reference to the flowchart of FIG.

When the control operation is started for the first time, the various input information described above, that is, the actual engine speed (N) and the opening degree (TVO) of the throttle valve 6 are read at predetermined time intervals, and then they are read. First, in step S ₁ , it is determined whether or not the current operating state is in the feedback control (F / B) region in the idle operating state shown in FIG. That is, the engine speed (N) is a predetermined value (Next)
Below is the minimum opening of the throttle valve 6 (TVOmin)
When, it is judged as the idle feedback control area,
On the other hand, the engine speed (N) is the predetermined value (Next)
Higher than, or the opening of the throttle valve 6 (TV
O) is larger than the minimum opening (TVOmin) by a predetermined value or more, it is determined to be in the non-feedback control region.

When in the idle feedback control region is (YES), program then proceeds to step S _2, the feedback control performs operation operation of the control value duty ratio for the feedback control signal for the idle speed control performed To do.

On the other hand, when the engine speed (N) is greater than or equal to a predetermined value (Next) or the opening (TVO) of the throttle valve 6 is greater than or equal to the minimum opening by a predetermined value or more, it is determined to be in the non-feedback control region (NO). It is recognized that the feedback control in step S ₂ is unnecessary, and the process shifts to open loop control to set a predetermined waiting amount to make a final output, and the control operation by the flow of the cycle is finished.

Next, in step S _3, capable of learning correction control condition, that is, the operating state of the engine determines whether it is in a no-load and the steady state. As a result, if YES, that is, if the learning correction condition is satisfied, the process further proceeds to step S ₄ , and the engine speed (N) and the engine cooling water temperature (Tw)
Is the actual deviation amount (correction value) ΔG _B from the basic characteristic value (basic control amount) G _B determined by and a predetermined value, that is, a value A that is large enough to require updating of the learning value? Determine whether or not. As a result, if YES,
Next, proceeding to step S ₅ , the ECU 9 controls the IC regulator of the alternator 15 to set the feedback current of the alternator 15 to a constant value (for example, zero). In addition, when this feedback current is set to zero, the power generation operation of the alternator 15 is stopped. As a result, it is possible to eliminate the adverse effect on the learning control due to the difference in the power generation state of the alternator 15 due to the presence of various electric loads as described in the section of the related art.

Then, start learning in step S ₆ ,
The learning value is updated in S ₇ , and the end of alternator control is set in step S ₈ to end the control operation of the cycle.

In this embodiment, one example of the duty control is shown, but current control, that is, the opening degree control of the bypass valve may be performed by the amount of current.

(Effects of the Invention) As described above, the present invention includes a target rotation speed setting unit that sets a target rotation speed of an engine when there is no load,
It is obtained by basic control amount setting means for setting a basic control amount for the engine so that the actual rotation speed of the engine at no load matches the target rotation speed, and the basic control amount set by this basic control amount setting means. A correction amount calculation means for calculating a correction amount for matching the actual rotation speed of the engine with the target rotation speed based on a deviation amount between the actual rotation speed of the engine and the target rotation speed, and the correction amount calculation means. Learning correction means for storing and updating the calculated correction amount as a correction value for the basic control amount set by the basic control amount setting means in a predetermined calculation cycle, and correcting the basic control amount with the stored and updated value. In an idle speed control device for an engine, the field power of an alternator driven by the engine is activated when the learning correction means is activated. The is characterized in the provision of the alternator control means for maintaining a predetermined value regardless of variations in electrical load.

Therefore, according to the present invention, when the learning correction means operates, the field current of the alternator is maintained at a predetermined value irrespective of changes in various electric loads, so the alternator as an engine load should be defined as a fixed value without load fluctuation. Therefore, even when determining the basic control amount for the learning correction control, it can be estimated as a value peculiar to the engine. As a result, no matter how the various electric loads or the battery voltage itself changes, the learning correction control value is not affected at all, and the learning accuracy is further improved.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to the claims of the present invention, FIG. 2 is a control system diagram of an engine idle speed control device according to an embodiment of the present invention, and FIG. 3 is a control in the embodiment device of FIG. FIG. 4 is a flow chart for explaining the operation, and FIG. 4 is a characteristic diagram showing the relationship between the throttle valve opening and the engine speed in the control operation of FIG. 1 …… Engine body 2 …… Air flow meter 6 …… Throttle valve 7 …… Bypass port 8 …… Solenoid valve 9 …… Engine control unit 12 …… Fuel tank 14 …… IC regulator 15 …… Alternator

Claims (1)

[Claims] 1. A target rotation speed setting means for setting a target rotation speed of the engine when there is no load, and a basic control amount for the engine so that the actual rotation speed of the engine when there is no load matches the target rotation speed. The basic control amount setting means, and the actual rotation speed of the engine based on the deviation amount between the actual rotation speed of the engine obtained by the basic control amount set by the basic control amount setting means and the target rotation speed. A correction amount calculation means for calculating a correction amount for matching the rotational speed, and a predetermined calculation of the correction amount calculated by the correction amount calculation means as a correction value for the basic control amount set by the basic control amount setting means. Memory update in a cycle,
In an idle speed control device for an engine, which comprises a learning correction means for correcting the basic control amount with the stored and updated value, an electric field current of an alternator driven by the engine is electrically supplied when the learning correction means operates. An idle speed control device for an engine, comprising an alternator control means for maintaining a predetermined value regardless of a change in load.