JPH0763149A - Method and device for controlling idle speed of internal combustion engine - Google Patents

Abstract

PURPOSE:To suppress a drop of speed of an engine and its blow up as small as possible by performing not only control of assist air by ISC but also control of advancing or delaying ignition timing. CONSTITUTION:An ignition timing correction amount corresponding to each load is provided in a manner of map or table, and the basic ignition timing is corrected in accordance with on/off conditions of each load. In this constitution, torque is estimated from changing an intake air amount Qa, and the ignition timing correction amount is calculated from the torque to correct the basic ignition timing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to idle speed control (ISC: Idle Speed) of an internal combustion engine such as a gasoline engine.
Control) method and apparatus therefor, and more particularly, to an idling speed control method and apparatus for an internal combustion engine that suppresses rotation drop and blow-up of the internal combustion engine by performing ignition timing correction in accordance with engine torque.

[0002]

2. Description of the Related Art Generally, a collector (surge tank) for distributing intake air to the intake pipe of each cylinder is provided in the middle of an intake pipe connecting a throttle and an internal combustion engine. If there is a large amount of air in the collector, the shock at the time of stepping on or off the accelerator will be small, and the drivability (driving feeling) will be good. On the contrary, if the amount of air in the collector is small, the air will suddenly enter or leave, and the drivability will deteriorate.

The intake air amount is measured by an air flow meter (air flow meter) such as a hot wire type, and an appropriate injection fuel amount is calculated based on the measured value. However, the amount of air in the collector is excluded from the measurement target of the air flow meter. Therefore, if the accelerator (throttle) is opened and the air in the collector is introduced all at once into the internal combustion engine, the balance of the appropriate ratio between the air amount and the fuel amount is lost due to the introduction of the excess air amount, and the rotation speed is A so-called rotation drop occurs in which the target rotation speed decreases without reaching the target rotation speed.

On the other hand, in order to maintain the idling speed at the time of idling (throttle is fully closed), by controlling the amount of auxiliary air flowing through the passage that is bypassed by the throttle valve, a constant idling speed is maintained. In many cases, an idle speed control (ISC) valve that can maintain the number is provided. When the engine rotation loss occurs with the accelerator opened as described above, even if the auxiliary air from the ISC valve attempts to prevent this, the engine rotation loss occurs and the rotation loss occurs.

On the contrary, when the accelerator is returned with the ISC valve open, the amount of auxiliary air corresponding to the opening of the ISC valve is added, so that the engine will blow up even though the engine speed is decreasing. In other words, the fact that the ISC valve assists to prevent the engine from falling
On the contrary, when the accelerator was returned, it caused a blow up.

FIG. 1 is a diagram showing such a conventional idle rotation speed control. In FIG. 1, when the load applied to the engine is turned on and off, the engine may fall or may blow up, so the ISC is used to control these problems.

[0007]

However, in the conventional idle speed control as described above, as is apparent from FIG. 1, the engine speed Ne tends to drop due to the load due to the increase in the intake air amount. Therefore, the ISC valve is opened to introduce the auxiliary air to prevent the engine speed Ne from falling off. However, due to the stroke delay and the air capacity downstream of the throttle valve, only the shaded area A is ISC. The opening of the valve (the flow rate of air that bypasses the throttle valve) becomes insufficient, and the engine speed Ne falls. On the other hand, when the accelerator is returned and the load disappears,
There is a delay until the ISC valve is completely closed, and the air flow rate that bypasses the throttle valve becomes excessive.
There is a problem in that the opening of C becomes excessive only in the shaded area A ′ and the engine speed Ne rises.

The present invention has been made in view of such problems of the conventional idle speed control, and its purpose is to:
Particularly, not only the auxiliary air control by ISC but also the advance or retard control of the ignition timing is performed, whereby the engine rotation speed drop and blow-up can be suppressed as much as possible, and an idle rotation speed control method and device thereof. Is to provide.

[0009]

In order to achieve the above-mentioned object, the idle speed control method and device of the present invention are basically each load acting on the internal combustion engine during idle operation. Of the required torque, the ignition timing correction amount is predetermined to correct the basic ignition timing according to the measurement result, and the ignition timing correction amount is corrected to the basic ignition timing when the load is turned on or off. It is characterized by that.

Further, the increase amount of the intake air amount supplied to the internal combustion engine during the load operation of the internal combustion engine relative to the idle operation is calculated, and the required torque of each load applied to the internal combustion engine is calculated from the increase amount. An example is one in which the ignition timing correction amount is estimated and the ignition timing correction amount is calculated according to a predetermined map according to the torque, and the ignition timing correction amount is corrected to the basic ignition timing.

[0011]

According to the present invention, the required torque for the idle at each load is measured, and the ignition timing correction amount corresponding to the required torque is determined. Further, the amount of increase in the intake air amount at the time of each load is calculated with respect to the idling time is calculated, the required torque is estimated from the amount of increase, and the ignition timing correction amount is determined from the ignition timing and torque table.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an idle speed control method for an internal combustion engine according to the present invention and an air-fuel ratio control apparatus used in the apparatus will be described in detail below with reference to the illustrated embodiments. FIG. 2 is an engine system diagram of this embodiment, and FIG. 3 is an example of a circuit block diagram of a control unit.

In FIG. 2, an air flow sensor (heat wire type air flow meter) 3 for detecting the flow rate of intake air filtered by the air cleaner 1 is provided on the intake side of the air cleaner 1 to the engine 7. The intake system communication path from the air cleaner 1 is connected to the engine 7 via the duct 4 and the collector 6.
Is connected to each intake pipe 8 connected to each cylinder. And, in the vicinity of the connecting portion between the duct 4 and the collector 6,
A throttle valve body 5 that accommodates a throttle valve (throttle valve) 5a that controls the intake flow rate is formed. The air to be taken in by the engine 7 is taken in from the inlet portion 2 of the air cleaner 1, passes through the hot-wire air flow meter 3, the duct 4, the throttle valve body 5 and enters the collector 6, and the intake air is taken in by the collector 6. It is distributed to the pipes 8 and guided into the cylinders of the engine 7. In addition, the throttle valve body 5 is provided with a bypass passage 22 that bypasses the throttle valve 5a, and an idle speed control (ISC) that controls the rotational speed during idling by controlling the air flow rate in the bypass passage 22. ) Valve 21
Are arranged.

On the other hand, fuel such as gasoline is sucked and pressurized by the fuel pump 10 from the fuel tank 9, and then passes through the fuel damper 11 and the fuel filter 12 to be provided with a fuel injection valve (for each cylinder). The injector 13 is adapted to inject into each suction pipe 8. Also,
Fuel pressure regulator (pressure regulator) 14
Are provided in these fuel piping systems and regulate the pressure to a constant pressure.

The control unit 30 receives signals from various sensors, performs predetermined arithmetic processing based on these signals, and performs fuel supply amount control and ignition timing control. A signal representing the intake flow rate is output from the air flow meter 3 and input to the control unit 30. A throttle sensor 18 for detecting the opening of the throttle valve 5a is attached to the throttle valve body 5, and its output is also input to the control unit 30.

The distributor 16 has a built-in crank angle sensor (not shown), and a reference angle signal REF indicating the rotational position of the crankshaft and a rotational speed (rotation speed).
An angle signal POS for detection is output, and these signals are also input to the control unit 30. An O ₂ sensor 20 is provided in the exhaust pipe to detect whether the actual air-fuel ratio is rich or thin with respect to the theoretical air-fuel ratio. This output signal is also input to the control unit 30.

As shown in FIG. 3, the control unit 30 includes an MPU 31 that executes various calculations, a ROM 32 that stores programs for the various calculations, a RAM 33 that stores various data, and an I / O. O LSI
And 34. Control unit 30
The I / O LSI 34 includes an idle switch 41, a crank angle sensor, a starter switch, a water temperature meter, and a battery voltmeter (all are not shown) in addition to the above-described hot wire air flow meter 3, O ₂ sensor 20, and throttle sensor 18. Is also connected. Each output signal from these sensors is I
The / O LSI 34 performs A / D conversion, and based on the various values that have been A / D converted, the MPU 31 executes predetermined arithmetic processing according to a program stored in the ROM 32. Various control signals calculated as the calculation result are sent to the fuel injection valves 13, 1 via the I / O LSI 34.
.. and the ignition coils 17, 17, and the fuel supply amount control and the ignition timing control are performed.

Next, the idle speed control method and apparatus of the present invention will be described. FIG. 4 is a diagram showing an ignition timing correction method according to an embodiment of the present invention, and shows an example of the outline of the present invention. According to the present invention, as shown in FIG. 4, when the load ON (OFF) is input, the ignition timing is intentionally advanced (retarded) to control the rise (fall) of the torque. It is possible to reduce the fluctuation of the engine rotation. That is, in one embodiment of the present invention, if the ignition timing is advanced, the insufficient torque can be compensated, and conversely, if the ignition timing is retarded, the excess torque can be eliminated, so that the engine It suppresses the fluctuations in the rotation speed as much as possible (details will be described later).

FIG. 5 is a relational diagram in which the intake air amount Qa and the torque T when a load is input are mapped, and
FIG. 6 is a relationship diagram in which the torque T and the ignition timing ADV are mapped. As shown in FIG. 5, the torque T increases as the intake air amount Qa increases according to the map as the torque estimating means. The map of FIG. 5 estimates and calculates the torque T _ID with respect to the air amount Qa _ID at idle (no load), and the map of FIG. 6 calculates the ignition timing correction amount ADV _ID with respect to T _ID and acts on the internal combustion engine. Load is ON
Then, the basic ignition timing is corrected. The map shown in FIG. 6 is ignition timing correction means for calculating an ignition timing correction amount to be corrected to the basic ignition timing.

Further, the torque T _i (for _i = 1, 2, 3, ...) At a certain load under the intake air amount Qa _i ( _i = 1, 2, 3, ...).
_i = 1, 2, 3, ...), that is, Q from Qa _ID to Qa _i
A value obtained by adding the increase amount of the torque T corresponding to the increase amount of a to T _ID is calculated. Then, the ignition timing correction amount ADV _i with respect to T _i is obtained from FIG. 6, and this is corrected to the basic ignition timing to advance the ignition timing ADV. In this way, the correction is performed by adding the ignition timing correction amount corresponding to the increase in the torque T to the basic ignition timing calculated value. Note that in FIG. 6, ADV ₁ and ADV ₂ indicate the ignition timing correction amounts at the start of the ignition timing correction in FIG. 4 (when the load is ON) and at the second ignition timing, for example. That is, initially, the torque T obtained from FIG.
_When the ignition timing correction amount ADV ₁ with respect to ₁ is corrected, the engine rotation drop can be prevented. However, if the ignition timing remains the same and the accelerator opening is kept constant, then the engine speed will increase too much as a reaction to the advance angle correction, so the ignition timing must be gradually decreased in order to prevent the fluctuation. Not (see ADV ₂ in Figures 4 and 6).

FIG. 7 relates to another embodiment of the present invention and shows an ignition timing correction value according to ON / OFF of each load. In this illustrated example, the ignition timing correction value corresponding to each load is held in the table as a fixed value, and the load O
A correction value is added to the basic ignition timing depending on N and OFF. That is, in FIG. 7, the electric load is a light,
Loads due to winkers, A / C loads are due to air conditioners, P / S are loads due to power steering, and correction values A _{1 to} D ₁ for ON / OFF of loads due to heater fans, and An example of A _{2 to} D ₂ is shown. For example, when the electric load is turned on by turning on the light, the calculated value of the ignition timing is added by 2 ° to advance the angle, and when the electric load is turned off by turning off the light, the angle is reduced by 2 ° and retarded. It controls the ignition timing.

Next, the present invention will be further described using a flow chart. First, according to FIGS.
The ignition timing advance correction in the case of N is described. FIG. 8 shows a method of obtaining the amount of change in Qa from the amount of change in ISC ON Duty when the load is ON, estimating the torque from the amount of change in Qa, and obtaining the ignition timing correction amount. In FIG. 8, the idle (IDLE) state is detected by the idle switch, and the Qa _ID at idling is read according to FIG. At that time, a load such as an electric load or an A / C load is detected. First, if it is the first time, a value corresponding to each load is retrieved from FIG. 7 and corrected, and the process ends. Two
After the first time, when the amount of change in ISC ON Duty per unit time is smaller than the predetermined value A, Qa _RL in the loaded state is read. Then, seeking Qa ₁ by Qa _RL -Qa _ID = Qa _1, estimates the torque T ₁ by FIG. Then, from FIG. 6, the advance correction amount of the ignition timing ADV for T ₁ is calculated and stored.

FIG. 9 shows a method of obtaining the amount of change in Qa after the lapse of t ₁ sec after the load is turned on, and estimating the torque from the amount of change in Qa to obtain the ignition timing correction amount.
In FIG. 9, the flow at the first time is the same as that in FIG. From the second time onward, t
After reading Qa _RL after ₁ sec, Qa _RL-
Qa ₃ is obtained from Qa _ID = Qa ₃ and stored in a predetermined address. Then, the torque T ₃ is estimated from FIG. 5, and the ignition timing advance correction amount is calculated from FIG. 6 and stored.

Next, referring to FIGS. 10 and 11, the load is turned off.
The retard correction of the ignition timing in the case of being performed will be described. FIG. 10 shows a method of obtaining the amount of change in Qa from the amount of change in ISC ON Duty when the load is off, estimating the torque from the amount of change in Qa, and obtaining the ignition timing correction amount. The illustrated example is basically performed in substantially the same manner as the flow of FIG. In FIG. 10, first, it is identified that the load detection has been switched from ON to OFF, and if it is the first time, a value corresponding to each load is retrieved from FIG. 7 and corrected, as in FIG. finish. If it is the second time or later, IS
The change amount of C ON Duty per unit time is a predetermined value B
If it is larger, read Qa _RL under load. Next, Qa ₂ is obtained by Qa _RL −Qa _ID = Qa ₂ , and the torque T ₂ is estimated according to FIG. Then, from FIG. 6, T ₂
Then, the retard correction amount of the ignition timing ADV is calculated and stored.

FIG. 11 shows T after the load is turned off.₂sec has passed
Then, calculate the amount of change in Qa and estimate the torque
It shows the method of determining the ignition timing correction amount
It This illustrated example is basically similar to the flow of FIG.
Done. The flow at the first time is the same as in FIG.
From the second time onward, t₂s
Qa after ec_RLAnd read from Figure 5 Qa_RL-Qa
_ID= Qa_FourBy Qa _Four Ask for it and give it the given address
To store. Then, from FIG. 5, the torque T_FourIf we estimate
In both cases, when calculating the ignition timing retard correction amount from FIG.
Stores in memory.

FIG. 12 shows a processing method after each load is detected and corrected. First, the correction amount of the ignition timing stored in FIG. 8 is read. Next, when the amount of change in ISC ON Duty after load detection per unit time is larger than the predetermined value A, Qa _ID 'during idling is read. Then, Qa _RL −Qa _ID '= Qa ₁ '
a ₁ ′ is obtained and stored at a predetermined address, the ignition timing correction amount is calculated according to FIG. 6, and the value is stored.

In FIG. 13, as shown in FIG. 7, the correction amount of the ignition timing with respect to each load is predetermined, and each time the load is turned on and off, the correction amount is added to the basic ignition timing to perform correction. Is to do. First, the intake air amount Qa is read to detect whether or not the load is in the ON state.
If the ON state of the load is not detected, the process ends. Load O
If the N state is detected, the increase amount of Qa is searched, the correction amount of the ignition timing is searched from the table of FIG. 7, and this is stored.
Next, it is detected whether or not the load is in the OFF state, and if not detected, the process ends. If the load OFF state is detected, Q
The decrease amount of a is detected, the correction amount of the ignition timing is searched from the table of FIG. 7, and this is stored.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-mentioned embodiments, and various designs can be made without departing from the present invention described in the claims. You can make changes. For example, the intake air amount Q
The ignition timing may be corrected by the increase amount of Qa when each load is turned on by learning the correction amount of the ignition timing corresponding to the torque fluctuation due to the change of a. According to the example of FIG. 7, when the electric load is ON, the basic ignition timing may be advanced by 2 ° first, and the advance correction amount may be gradually reduced.

[0029]

As is apparent from the above description, according to the present invention, not only the auxiliary air control by ISC but also the advance or retard control of the ignition timing is performed, so that the engine speed is decreased or blown up. Can be suppressed as much as possible.

[Brief description of drawings]

FIG. 1 is a diagram showing conventional idle rotation speed control.

FIG. 2 is a configuration diagram showing an example of an engine system of an internal combustion engine idle speed control device according to an embodiment of the present invention.

FIG. 3 is a block diagram of a control unit provided in the engine system of FIG.

FIG. 4 is a diagram showing an ignition timing correction method according to an embodiment of the present invention.

FIG. 5 is a diagram showing a relationship between an intake air amount and torque when a load is input.

FIG. 6 is a diagram showing a relationship between torque and ignition timing.

FIG. 7 is a diagram relating to another embodiment of the present invention and showing an ignition timing correction value according to each load.

FIG. 8 is a diagram showing a flowchart for obtaining a correction amount from a change amount of ISC ON Duty when the load is ON.

FIG. 9 is a diagram showing a flowchart for obtaining a correction amount after a certain time has elapsed after turning on the load.

FIG. 10 is a diagram showing a flowchart for obtaining a correction amount from a change amount of ISC ON Duty when the load is OFF.

FIG. 11 is a diagram showing a flowchart for obtaining a correction amount when a certain time has elapsed after the load is turned off.

FIG. 12 is a diagram showing a flowchart of processing after correction.

FIG. 13 is a diagram showing a flowchart of a correction amount for each load.

[Explanation of symbols]

3 ... Heat ray type air flow meter, 5 ... Throttle valve body, 6 ... Collector, 7 ... Engine, 21 ... Idle speed control valve, 22
... Bypass passage, 30 ... Control unit

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location F02D 45/00 366 F 376 C (72) Inventor Masami Nagano 2520 Takaba, Katsuta-shi, Ibaraki Stock Company Hitachi, Ltd. Automotive Equipment Division (72) Inventor Fukuya Itaya, Ibaraki Prefecture Katsuta City, Oita 2520 Takaba, Hitachi Ltd. Automotive Equipment Division

Claims (7)

[Claims] 1. When the internal combustion engine is idling, the required torque of each load acting on the internal combustion engine is estimated, and an ignition timing correction amount is set in advance to correct the basic ignition timing according to the estimation result. A method for controlling an idle speed of an internal combustion engine, comprising: correcting the ignition timing correction amount to a basic ignition timing when a load is turned on or off. 2. The increase amount of the intake air amount supplied to the internal combustion engine during the load operation of the internal combustion engine compared to the idle operation is calculated, and the required torque of each load applied to the internal combustion engine is calculated from the increase amount. An idling speed control method for an internal combustion engine, comprising: estimating and calculating an ignition timing correction amount according to a predetermined map according to the torque, and correcting the ignition timing correction amount to a basic ignition timing. 3. A change amount of the intake air amount is obtained after a lapse of a predetermined time from the time when each load is detected, and the required torque is estimated from the change amount of the intake air amount. The idle speed control method for an internal combustion engine according to claim 2. 4. A correction amount of ignition timing corresponding to a torque change amount due to a change in intake air amount supplied to the internal combustion engine is learned, and an increase amount of the intake air amount is measured when a load acts on the internal combustion engine. At the same time, the correction amount of the ignition timing obtained by learning is corrected to the basic ignition timing. 5. An idle state detecting means for detecting an idle state of the internal combustion engine, a torque estimating means for estimating a required torque of each load in the idle state of the internal combustion engine, and an estimated torque obtained from the torque estimating means. Ignition timing calculation means for calculating an ignition timing correction amount to be corrected to the basic ignition timing, and means for correcting the ignition timing correction amount to the basic ignition timing when each load is turned on or off. An idle speed control device for an internal combustion engine, characterized in that 6. A means for calculating an increase amount of an intake air amount supplied to the internal combustion engine during a load operation of the internal combustion engine during a load operation, and a required torque of each load applied to the internal combustion engine from the increase amount. A torque estimating means for estimating the ignition timing, an ignition timing calculating means for calculating an ignition timing correction amount to be corrected to the basic ignition timing according to the estimated torque obtained from the torque estimating means, and the calculated ignition timing correction amount. An idle speed control device for an internal combustion engine, comprising: a means for correcting the basic ignition timing. 7. The torque estimating means is means for estimating the required torque according to the amount of change in the intake air amount calculated after a lapse of a predetermined time from the time when each of the loads is detected. The idle speed control device for an internal combustion engine according to claim 6.