JPH068298Y2 - Ignition timing control device for internal combustion engine - Google Patents

Description

[Detailed description of the device]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition timing control device for an internal combustion engine such as an automobile, and more particularly to an ignition timing control device for an internal combustion engine that shortens the time until idle stabilization at engine startup. (Prior Art) In recent years, electronic control of engine control has progressed, and a combustion state of the engine is determined by a microcomputer based on operating conditions, and parameters related to the combustion state (for example, injection amount, ignition timing) are controlled. Electronic control devices are widespread. In addition, the demand for internal combustion engines such as automobiles is becoming more advanced, and there is a tendency for achieving high levels of conflicting issues such as reduction of harmful exhaust gas, high output, and low fuel consumption. Such requirements can be realized only by using a microcomputer. On the other hand, at idle, since the rotation speed is low, even slight fluctuations in rotation cause deterioration of stability, deterioration of fuel efficiency, vibration generation, etc.Therefore, finely controlling the combustion state for each cylinder has been performed recently. This is called so-called idle active control. The present invention has the above technical background. A conventional combustion control device of this type of internal combustion engine is disclosed in, for example, Japanese Patent Publication No. 62-42153.
In this device, a correction control value that gives an average value of the knock limit of each cylinder in each operating state of the engine is stored, and the correction control value and the sequential correction obtained by calculating the knocking signal generated for each cylinder are stored. By correcting the reference control value for each cylinder in each operating state of the engine with the correction value that combines the values, and updating the correction control value based on the sequential correction value of each cylinder in a predetermined cycle, a slight sequential The correction value accurately suppresses knocking, improves the response of knocking suppression control when the operating state changes, and controls the ignition timing of each cylinder to the individual knocking limit over all operating states. This also applies to the idle state, and in particular, idle control from the start is executed by the program shown in FIG. In the figure, first, when the key switch is operated and the engine starts cranking, the microcomputer is started at the same time, and a uniform value for each cylinder is read from the memory and set as the ignition timing ADV at the time of starting at P _1. . Generally, for example, a value of about 15 ° BTDC is set. At this time, the correction amount of the ignition timing ADV is

It is [0]. That is, the ignition timing ADV at the time of starting is always a fixed value regardless of winter, summer, etc., and regardless of the restart interval from the previous time. Then, the idle switch is determined whether the ON at _{P 2,} when the ON running idle active control with _P 3 to P _5, since the time of OFF is other than idling, jumps to _{P 6} . P ₃ In the detection of the fuel state at idle (e.g., the presence or absence of knocking, detection of rotational fluctuation), and calculates a correction value of the ignition timing ADV for each cylinder on the basis of the detection result by the P _4. The correction value is for stabilizing the idle, etc. so that the optimum combustion state is obtained.
For example, the size is set every 1 ° (1 ° for one routine execution). Then, by correcting the ignition timing ADV by the correction value P _5, to determine the ignition timing for each cylinder to ignite air-fuel mixture. As a result, idle active control is performed. Then, the key switch is determined whether or not OFF at P _6, when it is ON, returns to P ₂ stores the correction value in P ₇ in the memory, the program is terminated when turned OFF. (Problems to be solved by the invention) However, in such a conventional combustion control device for an internal combustion engine, the ignition timing at the time of starting has a fixed value that is uniform for all cylinders. Even if the idle active control is performed by executing the above, there is a problem that it takes a long time (for example, about 5 minutes) until the idle is further stabilized. (Object of the Invention) Therefore, an object of the present invention is to provide an ignition timing control device for an internal combustion engine that can shorten the time until the idle is further stabilized by devising the determination of the ignition timing at the time of starting. There is. (Means for Solving the Problem) In order to achieve the purpose, an ignition timing control device for an internal combustion engine according to the present invention has an idle detection means a for detecting an idle state of the engine as shown in the basic conceptual diagram of FIG. A cooling water temperature detecting means b for detecting an engine cooling water temperature, a combustion state detecting means c for detecting a combustion state of each cylinder, a basic ignition timing setting means d for setting a basic ignition timing at the time of starting and idling, When the engine shifts to the idle state, the ignition timing correction amount for idle is calculated for each cylinder so that the output value of the combustion state detecting means c reaches a predetermined target state, and the actual cooling water temperature is equal to or lower than the predetermined cooling water temperature. In this case, an average value of the ignition timing correction amounts for each idle is stored in correspondence with the cooling water temperature, and the average value is used as an initial value of the ignition timing correction amount for the next start. When the engine is started, the initial value of the ignition timing correction amount for starting is read corresponding to the cooling water temperature at the time of starting, the basic ignition timing is corrected based on the read initial value, and when the engine shifts to the idle state, Ignition timing setting means f for correcting the basic ignition timing for each cylinder based on the idle correction amount. (Operation) In the present invention, the average value of the ignition timing correction amount for idle of each cylinder when the actual cooling water temperature is equal to or lower than the predetermined cooling water temperature is stored corresponding to the cooling water temperature, and at the next engine start,
The ignition timing is corrected with the correction amount for the cooling water temperature at that time as an initial value. Therefore, the combustion state at the time of engine start is promptly controlled to an appropriate state, and the time until the idling stabilizes is shortened. At this time, since the correction amount is stored using the cooling water temperature as a parameter, even if the engine and environmental conditions from the engine stop to the next start are different, the correlation of the correction amount from the engine stop to the time start is long-term. The ignition timing at the time of engine start is corrected by a correction amount that is held for a long period of time and that corresponds to the environmental conditions at that time. (Example) Hereinafter, the present invention will be described with reference to the drawings. 2 to 6 are views showing an embodiment of a combustion control device for an internal combustion engine according to the present invention. In this embodiment, the first device is applied to a 4-cylinder engine. First, the configuration will be described. In FIG. 2, reference numeral 1 denotes a crank angle sensor, and the crank angle sensor (crank angle detecting means) 1 has a predetermined position before the compression top dead center (TDC) of each cylinder at every explosion interval (180 ° CA), for example, BTDC70. In addition to outputting the reference signal REF that becomes a [H] level pulse at 0 °, it also outputs a unit signal POS that becomes a [H] level pulse to the control unit 2 for each unit angle of the crank angle (for example, 1 °) ( Umbrellas (a), (b)).
Further, 3 is a counter of 1 MHz, and when the reference signal REF of the crank angle sensor 1 is input to the control unit 2, the counter 3 has arbitrary sections θ _{1 to} θ ₂ , as shown in FIG. The time Ni between θ _{3 and} θ ₄ ° CA is measured. It should be noted that the sections θ _{1 to} θ ₂ and θ _{3 to} θ ₄ ° CA have optimal sections set beforehand by experiments or the like, and their thorough values can be arbitrarily changed by ROM22 data in the control unit 2 described later. it can. Flow rate Q _a of intake air is detected by the air flow meter 4, the temperature T _w of cooling water flowing through the water jacket is detected by the water temperature sensor 5 (the cooling water temperature detecting means). Further, the opening degree TVO of the closing valve is detected by the closing valve sensor 6, and the idle opening of the closing valve is detected by the idle switch (idle detecting means) 7. Further, the start / stop of the engine is detected by the key switch 8. The crank angle sensor 1, the air slow meter 4, the water temperature sensor 5, the closing valve opening sensor 6 and the key switch 8 constitute an operating state detecting means 10, and the outputs from the operating state detecting means 10 and the idle switch 7 are It is input to the control unit 2. The control sonit 2 has a function as a basic ignition timing setting means, a correction amount calculating means and an ignition timing setting means by itself, and the control unit 2 constitutes a combustion state detecting means 11 together with the crank angle sensor 1. Control unit 2 is CPU21,
It is composed of a microcomputer including a ROM 22, a RAM 23 and an I / O port 24. CPU21 is ROM
I / O port according to the program written in 22
Take in external data you need from 24 or RA
While exchanging data with M23, processing values and the like necessary for ignition timing control are arithmetically processed, and the processed data is output to the I / O port 24 as necessary. ROM22 is C
A program that controls PU21 is stored in RAM23
Temporarily stores data used for calculation, and the stored data is backed up by a battery. The I / O port 24 has signals from the sensor groups 1, 4, 5, 6, 7, 8 and the counter 3
In addition to the input of the information from, the injection signal Si and the ignition timing Sp are output from the I / O port 24 to the injectors 25a to 25d and the power transistor 26, respectively. When the amplified ignition signal is input to the base side of the power transistor 26 (when the power supply to the power transistor 26 is stopped), the power transistor 26 is turned off to output from the battery 28 supplied to the ignition coil 27. The temporary current is cut off to generate the high voltage pulse Ph on the secondary side. Then, this high-voltage pulse Ph is distributed and supplied to the spark plugs 30a to 30d of each cylinder via the distributor 29. The power transistor 26, the ignition coil 27, the battery 28,
The distributor 29 and the spark plugs 30a to 30d constitute the ignition means 31. The ignition means 31 has a function as an operation means for operating the ignition timing as a parameter for controlling the combustion state. Next, the operation will be described. FIG. 4 is a flowchart showing a program for detecting the combustion state from the rotation fluctuation, and this program is executed once every predetermined period. First, at P ₁₁ , 1 MHz based on the POS signal after the REF signal input of the crank angle sensor 1
As shown in FIG. 3 (c), the counter 3 of θ ₁ to θ ₂ °
Time Ti between CA and time T between θ ₃ and θ ₄ ° CA
i ′ is calculated according to the following equation, and at P ₁₂ , the time Ti and 90 °
From the time Ti ′ after CA, the change in the number of revolutions of the previous time and the present time (change in the angular velocity) N _{e. i} is calculated. (See FIG. 3 (d)), the deviation ΔNe in the change of the rotational speed is further calculated according to the following equation. Ti = θ ₂ −θ ₁ Ti ′ = θ ₄ −θ ₃ } ... However, K: constant ΔNe = N _{e. i-1-} N _{e. i} ... However, N _{e. i-1} : Amount of change in previous rotation number ΔNe changes every 180 ° CA, and represents the combustion state at that time. Next, at P ₁₃ , this ΔNe is stored in a predetermined memory, and this routine is ended. The above steps P _{11 to} P ₁₃ are for detecting Pi fluctuation (combustion fluctuation) for each cylinder based on the close correlation between the engine rotation and the indicated mean effective pressure Pi of the cylinder. Specifically, the engine rotation during idling is 180 at top and bottom dead center.
It is greatly affected by the indicated mean effective pressure Pi of the cylinder that is in the combustion / expansion stroke at that time between ° CA. That is, the combustion state at that time cannot be detected by the absolute value of the rotational speed, but as shown in FIG. 5, TDC to 90 ° C.
If the rotation fluctuation for each A is measured, the indicated mean effective pressure Pi of the burned cylinder can be detected. Then, the control of the combustion state is executed by the program shown in FIG. 6 based on the detection data Pi. FIG. 6 is a flowchart showing an ignition timing control program. This program starts at the same time as the engine starts and is executed once every predetermined period. Simultaneously with the start of the cranking of the engine, first, the cooling water temperature Tw is read in P ₃₀ , and the correction value (corresponding to the correction amount in the claims is calculated from the map stored for the cooling water temperature Tw at that time in P _31). The same applies hereinafter) is read as an initial value. In the map, a correction value is stored by dividing the area for each water temperature by an averaging process described later, and this is an initial value. This correction value is not a fixed value (for example, BTD 15 °) as in the past, but is described in steps P _{32 to} P described later.
It is calculated by ₃₆ . Then, using this correction value, the ignition timing ADV, for example, the fixed value (BT
DC15 °) is corrected and the mixture is ignited. Therefore,
Although the ignition timing at the time of starting is appropriately corrected, this effect will be described later for convenience of description. Then when the engine starts,
P ₂ to P performs the same processing as the conventional example shown in ₆ in FIG. 7. In this case, in the present embodiment, the _third step is performed in P3.
The combustion state is detected for each cylinder by the program shown in the figure. The detection of the combustion state is not limited to the method of this embodiment, and for example, a method of providing an in-cylinder pressure sensor for each cylinder and directly detecting the pressure in the combustion chamber may be used. . Further, in the step P ₄ , the correction value of the ADV for each cylinder is calculated so that the combustion state becomes the predetermined target state. If the NO branch is followed at P ₆ , then the cooling water temperature Tw is read at P ₃₂ , and this is compared with the predetermined value T _wo at P ₃₃ . When the Tw ≦ _{T wo} performs processing for calculating the moving average step P ₃₄ to P _36. P when Tw> T _wo
Jump to ₃₇ . The predetermined value T _wo is set to an optimum value by an experiment in advance as a value for obtaining a correction value that correlates with the cooling water temperature immediately after the start. The reason for jumping to ₃₇ when Tw> T _wo is because the water temperature rises and it can no longer be said that the correction value correlates with the start. Reads out the correction value for the cooling water temperature Tw at this time in the P ₃₄ up to the previous from RAM 23, it calculates the moving average of the current correction value for the cooling water temperature Tw at P _35. The moving average is obtained, for example, by averaging the correction values of the previous time and this time at a predetermined ratio (such as 15/16 and 1/16). This is to improve the accuracy while ensuring the reliability of the data. Thus, the value of the moving average is obtained as a value correlated with the cooling water temperature Tw immediately after the start. Then stores the correction value calculated in this way in the P ₃₆ to RAM23 of the battery backup, and corrected by the correction value of the ignition timing AVD at P _37, returns to P _2. In the above program, in the present embodiment, the average value of the ignition timing correction values for idle of each cylinder when the actual cooling water temperature is equal to or lower than the cooling water temperature Tw is set as the correction value of the ignition timing ADV with respect to the cooling water temperature Tw at the present start. Since this is adopted, the ignition timing at the time of starting is not fixed uniformly, but corresponds to the cooling water temperature Tw at that time. Therefore, the combustion state at the time of engine start is promptly controlled to an appropriate state, and the time until the idling stabilizes is shortened. For example, it can be half or about 1/3. As a result, the drivability of the engine can be improved. In addition, since the correction value is stored using the cooling water temperature as a parameter, even if the period from engine stop to the next start or environmental conditions are different, the correlation of the correction value from the engine stop to the next start can be maintained for a long time. The ignition timing at the engine start can be corrected with a correction value according to the environmental conditions at that time. (Effect) According to the present invention, the average value of the ignition timing correction amount for the idle of each cylinder when the actual cooling water temperature is equal to or lower than the cooling water temperature,
Since this time it is used as a correction value for the ignition timing with respect to the cooling water temperature at the start timing, it is possible to quickly control the combustion state at the time of engine start to an appropriate one, and to significantly increase the time until the idle becomes more stable. It can be shortened. As a result, the drivability of the engine can be improved. Also, because the cooling water temperature is stored as a parameter and correction amount, even if the engine and environmental conditions from engine stop to the next start are different, the correlation of the correction amount from engine stop to the next start can be maintained for a long time. The ignition timing at the engine start can be corrected with a correction amount according to the environmental conditions at that time.

[Brief description of drawings]

FIG. 1 is a basic conceptual diagram of the present invention, and FIGS. 2 to 6 are diagrams showing an embodiment of a combustion control device for an internal combustion engine according to the present invention.
2 is an overall configuration diagram, FIG. 3 is a waveform diagram showing signal waveforms of respective parts, FIG. 4 is a flow chart showing a program for detecting the rotation fluctuation, and FIG. 5 is a relationship between the average effective pressure and the rotation fluctuation. FIG. 6 is a flow chart showing a program for ignition timing control thereof, and FIG. 7 is a flow chart showing a program for combustion control of a conventional internal combustion engine. 2 ... Control unit (basic ignition timing setting means,
Correction amount calculation means, ignition timing setting means), 5 ... Water temperature sensor (cooling water temperature detection means), 7 ... Idle switch (idle detection means), 11 ... Combustion state detection means.

Claims (1)

[Scope of utility model registration request] 1. A) idle detection means for detecting an idle state of the engine; b) cooling water temperature detection means for detecting a cooling water temperature of the engine; and c) combustion state detection means for detecting a combustion state of each cylinder. d) basic ignition timing setting means for setting basic ignition timing at the time of starting and idling; and e) idling so that the output value of the combustion state detecting means reaches a predetermined target state when the engine shifts to the idling state. The ignition timing correction amount for each cylinder is calculated, and the average value of each idle ignition timing correction amount when the actual cooling water temperature is equal to or lower than the predetermined cooling water temperature is stored corresponding to the cooling water temperature, and the average value is stored next time. Correction amount calculation means for setting the initial value of the ignition timing correction amount for starting, and g) when the engine is started, the initial value of the ignition timing correction amount for starting is read corresponding to the cooling water temperature at the time of starting. Is corrected based on the initial value read the basic ignition timing,
An ignition timing control device for an internal combustion engine, comprising: ignition timing setting means for correcting the basic ignition timing for each cylinder based on the idle correction amount when shifting to an idle state.