JPH0641746B2 - Electronic ignition control method for internal combustion engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electronic ignition control method for an internal combustion engine, and more particularly to an electronic ignition control method for preventing excessive engine rotation.

(Technical background of the invention and its problems) Detecting a plurality of predetermined crank angle positions of an internal combustion engine,
An electronic ignition control method is known in which a predetermined arithmetic control processing operation for ignition control is executed every time each predetermined crank angle position is detected. In such a control method, since the time interval for detecting the predetermined crank angle position is gradually shortened as the engine speed increases, the above predetermined arithmetic control is performed for each predetermined crank angle position detection even in the high rotation region. In order to complete the processing operation, the content of the processing operation that can be processed with itself is limited, and only the processing operation to be executed with priority is executed at each predetermined crank angle position detection.

By the way, if the engine speed exceeds a predetermined speed and enters the overspeed range for the purpose of preventing engine overheat, etc.,
A control method for inhibiting ignition of the air-fuel mixture by the spark plug is also known. In this control process, a predetermined time is required for a series of processes (hereinafter, referred to as "overspeed determination process") for determining whether the engine speed has entered the overspeed region and prohibiting ignition. Therefore, if this over-rotation determination processing is executed for each predetermined crank angle position detection, the calculation time cannot be secured in the high-rotation region, so conventionally, this is utilized by using the idle time after the processing with high priority is completed. Was being conducted. However, if the over-rotation determination processing is performed because of the above-described idle time, the idle time that should be used in the over-rotation region cannot be secured, and the crankshaft may make one rotation without completing the over-rotation determination processing. In such a case, for example, in a no-load state where the clutch of the engine is disengaged, the engine speed rapidly increases during this period, which causes a problem.

(Object of the Invention) The present invention has been made in view of the above-mentioned problems, and when the engine enters an overspeed region, this is detected without time delay to prohibit ignition of the air-fuel mixture to prevent overheating of the engine. Another object of the present invention is to provide an electronic ignition control method for an internal combustion engine.

(Structure of the Invention) In order to achieve the above object, according to the present invention, a plurality of predetermined crank angle positions of an internal combustion engine are detected, and a predetermined ignition control is performed each time each predetermined crank angle position is detected. In the electronic ignition control method for executing the arithmetic control processing operation, at least one of the plurality of predetermined crank angle positions is used.
The crank angle between one specific crank angle position and the predetermined crank angle position detected immediately after the detection of the specific crank angle position is set to a value larger than the crank angle between two other adjacent predetermined crank angle positions, When the crank angle position of the characteristic is detected, the engine speed is detected, and when the detected engine speed is equal to or higher than a predetermined speed,
An electronic ignition control method for an internal combustion engine is provided, which comprises generating a signal that blocks ignition and prohibiting ignition while the blocking signal is generated.

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

FIG. 1 is an overall configuration diagram of an electronic ignition control device to which the present invention is applied. In the figure, reference numeral 1 is an in-line 4-cylinder engine, 2 is an electronic control unit (ECU), and the engine 1 is an in-line 4-cylinder engine. Engines with 45 °, 60 °, 90 °, 128 °, 135 ° etc. (hereinafter referred to as “bank angles”) may be used. FIG. 1 shows a partial cross-section of a main part of one of the plurality of cylinders. Reference numerals 10a and 10b are spark plugs, and although only two spark plugs are shown in the drawing, these spark plugs are separately attached to respective cylinders. Further, as will be described later, each of the spark plugs 10a and 10b is connected to a separately provided ignition coil so that an ignition method without a distributor is adopted. For a 4-cylinder engine, another spark plug (not shown) is electrically connected in series to the spark plug 10a, and similarly, a spark plug 10b is also not shown. One spark plug is electrically connected in series. Each of the two spark plugs connected in series is discharged with the same spark signal, and one of the two spark plugs discharged at the same time is discharged in the exhaust stroke. Be taken. Reference numeral 3 is a combustion chamber of the engine 1, and the combustion chamber 3
An intake pipe 4 and an exhaust pipe 5 are communicated with each other, and an intake valve 6 and an exhaust valve 7 are provided at each communication port. A throttle valve 8 is provided in the middle of the intake pipe 4,
A negative pressure sensor or an absolute pressure sensor (hereinafter simply referred to as “intake pressure sensor”) 9 is provided downstream of the throttle valve 8. The intake pipe internal pressure signal converted into an electric signal by the intake pressure sensor 9 is transmitted to the ECU 2 Sent to. The cylinder peripheral wall of the engine 1 is filled with cooling water, and an engine water temperature sensor 11 including a thermistor or the like is inserted in this portion. The detection signal of this engine water temperature sensor 11 is E
It is supplied to CU2. 12 is a piston, this piston 1
2 is connected to a crankshaft 14 via a connecting rod 13 and, according to the rotation of the crankshaft 14, first and second pulses as shown in FIGS. A pulse generating mechanism for generating the signals Pc ₁ and Pc ₂ is provided. That is, first, the rotating disk 15 is attached to the crankshaft 14, and the reactors 16a to 16g formed by the protrusions made of a ferromagnetic material are arranged on the circumference of the rotating disk 15.
Projections are provided at equal positions excluding parts, for example, at an angle of 45 °. In the illustrated example, the reactor is the reactor 16d.
And 16e, only one portion is missing, and the angular interval of this missing portion is 90 °. It should be noted that the magnetic material may be embedded in the rotating disk without being limited to the reactor protrusion. The magnets 17a, 18a are provided outside the rotating disk 15 along the circumference thereof.
First and second coils formed by winding coils 17b and 18b around
Electromagnetic pickup (hereinafter referred to as "Pulsa") 17,1
8 are provided. First and second pulsars 17, 18
The arrangement angle interval of is the interval of the top dead center of the applied engine,
It is defined according to the number of cylinders, etc., and in the example shown in the figure, the top dead center interval is 1.
The case of application to an 80 ° in-line 4-cylinder engine is shown, and the arrangement angular interval between the two pulsars 17 and 18 is about 1.
It is regulated at 80 °.

On the other hand, the ECU 2 is roughly divided into blocks. The input circuit 19 and the input / output LSI (hereinafter referred to as “I / 0.LS”).
21), a central processing unit "hereinafter referred to as" CPU ") 22, an A / D converter 23, and first and second output circuits 24a and 24b. Further, the input circuit 19 waveform-shapes the first and second pulse signals Pc ₁ and Pc ₂ (FIGS. 5A and 5B described later) generated by the first and second pulsers 17 and 18, respectively. Waveform shaping circuit 2
5, 26 and first and second flip-flop circuits 27, 28 for latching the outputs from the waveform shaping circuits 25, 26, respectively. The output line of the first flip-flop circuit 27 is CP via I / O.LSI21.
It is connected to the INT terminal (not shown) of U22, and the second
In the flip-flop circuit 28 of, the output line of the Q output is I
It is connected to the STATUS terminal (not shown) of the CPU 22 via the /0.LSI21. Reference numeral 29 is a clear signal line for the first and second flip-flop circuits 27 and 28.

The CPU 22 executes various programs for calculating the energization timing and the ignition timing, and has the above-mentioned calculation program, Ne.P _B -θig map, which will be described later, inside thereof.
A read-only memory (hereinafter referred to as "ROM") 31 that stores a Tw-Δθig table, a bank angle table, and the like,
In addition, a random access memory (hereinafter referred to as “RAM”) 32 for storing the above calculation results and the like, an input / output buffer 33, and an internal counter 34 that functions as an energization counter are provided in the CPU. ing. Reference numerals 34a and 34b denote registers for storing the energization timing data in the RAM 32, and reference numeral 3 shown by a broken line
Reference numerals 5a and 35b compare the count value of the internal counter 34 with the stored contents of the energization timing data of each register 34a, 34b, and when the count value and the stored value match, the CPU 22
9 is a diagram schematically showing a program process for outputting a predetermined high level (hereinafter referred to as "1" level or "H" level) to the terminals 22a, 22b of.

"1" level output as the energization signal on the side of the spark plug 10a to the terminal 22a of the CPU 22 and "1" output as the energization signal on the side of the ignition plug 10b to the terminal 22b.
The level is led to the respective energization signal lines 40a and 40b to the first and second output circuits 24a and 24b via the I / O LSI 21, respectively.

On the other hand, the I / O LSI 21 has a first ignition counter 36 for the ignition plug 10a and another ignition plug 10b.
A second ignition counter 37 for the is provided. Reference numeral 38 is an ignition register for latching ignition timing (energization stop timing) data on the side of the spark plug 10a, and reference numeral 39
Is an ignition register for latching ignition timing data on the spark plug 10b side, and 42 and 43 are first and second comparators. The first and second ignition counters 36 and 37 have C
Starting signal lines are connected from the PU 22 respectively. The output line 44a of the first comparator 42 communicates with the first output circuit 24a and the output line 44a of the second comparator 43.
44b communicates with the second output circuit 24b. Reference numerals 45 and 4
Reference numeral 6 denotes first and second ignition coils, and these ignition coils 45 and 46 are respectively provided with a primary coil and a secondary coil (not shown). The output line from the first output circuit 24a is connected to the primary coil of the first ignition coil 45, and the secondary coil is connected to the ignition plug 10a. The output line from the second output circuit 24b is connected to the primary coil of the second ignition coil 46,
The secondary coil is connected to another spark plug 10b.
Reference numeral 47 in the I / O / LSI 21 portion is a Me timer described later.

Next, the operation of the electronic ignition control device will be described with reference to FIGS. 2 to 5. 2 to 4 are flowcharts of the ignition timing control procedure executed by the CPU 22.

First, referring to the flowchart of the main routine in FIG. 2, when an ignition switch (not shown) is turned on, immediately after that, initialization processing of the CPU 22 and the like is performed, and then in step 51, the crank angle reference position is detected. Done. After the reference position is detected, the time Me required for one revolution of the crankshaft 14 is calculated (step 52), the advance angle data θig is calculated, and the calculated value is stored in the RAM 32 (step 53). The energization time To _N And store processing of the calculated value in the RAM 32 (step 5
4), the energization stop timing based on the advance angle data θig and the energization time To _N , that is, the calculation of the ignition timing data Tig and the energization timing data Tcg, and the storage of these calculated values in the RAM 32 (step 55) are sequentially performed. The respective arithmetic processings are repeated when the interrupt processing program INT described later is not executed.

Next, the processing in each of the above steps will be described in detail. In step 51 of reference position detection, when the first pulse signal Pc ₁ is input to the CPU 22 as shown in FIG.
2 is the Q output of the second flip-flop circuit 28 (see FIG. 5).
(d)) is at "H" level or "L" level. At this time, the portion (shown by the k line in FIG. 5 (d)) where the Q output of the second flip-flop circuit 28 is at the “L” level at the timing when the first pulse signal Pc ₁ is input. It exists once per one revolution of the crankshaft 14. The crank angle position at this time is defined as a reference crank angle position q. After the reference crank angle position q is detected, each generation interval of the _first pulse signal Pc ₁ is defined as a stage, and a stage number is assigned to each stage. This number can be assigned in various ways according to the bank angle of the engine 1. The number of the stage in which the reference crank angle position q is detected is determined by the ROM 3 for each engine specification.
It is stored in 1. In the example of FIG. 5 (a), the reference position q
Is numbered as a stage 1, and is numbered as stages 2, 3 ...

After detecting the reference crank angle position q, the Me value is calculated in step 52. The calculation of the Me value is performed by the interrupt processing program shown in FIG. 3, which will be described later, when each generation time interval Tsi (i = 1 to 7) of the first pulse signal Pc ₁ (FIG. 5 (a)) is M
e Measured by clock pulse by timer 47, 1
The total time Me of the rotation is calculated. From this total time Me, the time Ts required for the crankshaft 14 to rotate for one stage, in other words, for a crank angle of 45 °.
= Me ÷ 8 and the time ΔT = Ts ÷ 45 required to rotate the crank angle by 1 °, which is calculated by the RAM 3
2 and prepares for calculation processing of ignition timing Tig and the like which will be described later.

Next, at step 53, the advance angle data θig from the reference crank angle position q is calculated, and the calculation result is stored. The advance angle data θig includes the Me value and the intake pressure sensor 9
And the respective values of the intake pipe internal pressure P _B and the engine water temperature Tw detected by the engine water temperature sensor 11, respectively, are calculated according to the following equation (1).

here Indicates basic advance angle data, which is a function of the engine speed Ne and the intake pipe pressure P _B. And Ne · P _B −θi stored in the ROM 31.
It is read from the g-map. Δθig is a correction value of the advance angle data, and for example, the value is a function of the engine temperature Tw (Δθi
g = f (Tw)), which is read from the Tw-Δθig table stored in the ROM 31. The value of the advance angle data θig is specified with the maximum advance angle θig (for example, 60 °) as the upper limit, and when the value obtained as described above exceeds this maximum advance angle θig, the maximum advance angle θig It is corrected to the value of the advance angle θig. The lead angle data θig thus obtained is stored in the RAM 32.

Next, at step 54, the energization time To _N is calculated and the calculation result is stored. The energization time To _N is a function of only the engine speed Ne as shown in the following equation (2), and is read from the Ne-To _N table stored in the ROM 31 as described above.

To _N = f (Ne) (2) The energization time data To _N thus obtained is the RAM 3
Stored in 2.

After the advance angle data θig and the energization time data To _N are obtained, the ignition timing data Tig and the energization timing data Tcg are calculated in step 55 based on these values. First, the ignition timing data Tig will be described. For each bank angle of the engine and each cylinder, the stage number at the position advanced by the maximum advance angle θig 'from the crank angle reference position q (in the example of FIG. ) And angle data are stored in the ROM 31. The CPU 22 reads out the angle data, the advance angle data θig, and the like from the ROM 31 and the RAM 32, respectively, and calculates the angle DEG from the stage 6 pulse q ′ by the following equation (3).

DEG = θig′−θig + angle data (3) Next, the ignition timing data Tig is calculated from the angle DEG by the equation (4).

Tig = ΔT × DEG (4) Here, ΔT is the time stored in the RAM 32 in step 52 and required for the crankshaft 14 to rotate by 1 ° in crank angle.

Regarding the energization timing data Tcg, the ignition timing data Tig and the energization timing data To _N obtained as described above are used.
From this, calculation is performed using the following equation (5).

_{Tcg = | (To N -Tig)} -Ts × m | ... (5) where m is the maximum advance angle θig advanced by the position of the stage earlier the ignition coil (FIG. 5 in the illustrated example stage 6) from The number of stages up to the stage at which energization is started (m = 1 in the example shown in FIG. 5), Ts is the average value of the time required for the crankshaft to advance the crank angle of 45 ° obtained in step 52. The calculated values are stored in the RAM 32.

Next, the execution of energization and ignition will be described with reference to the flowchart of FIG. The interrupt operation processing program INT shown in FIG. 3 is executed at the highest priority every time the output from the first flip-flop circuit 27 is input to the CPU 22.

First, in step 56, the stage position is detected, and then the current measured value Ts (n) of the generation time interval of the pulse signal Pc ₁ is read from the Me timer 47, and after storing this value, the Me timer 47 is reset. It is restarted (step 57). Next, at step 58, it is judged if the stage detected at step 56 is the ignition stage (for example, the sixth stage) at which the ignition counter circuit 36 should start counting. This determination result is affirmative (Y
If es), the CPU 22 sends an activation signal to the ignition counter circuit 36 to activate the ignition counter circuit 36 (step 59, FIG. 5 (f)), and proceeds to step 60. On the other hand, if the determination result of step 58 is negative (No), the process directly proceeds to step 60 to start the internal counter 34 which is an energization counter (FIG. 5 (g)). The energization counter 34 is started each time the interrupt processing program is executed. Next, in step 61, it is determined whether the engine speed Ne is equal to or higher than a predetermined speed (for example, 5000 rpm). This determination result is affirmative (Yes)
If so, energization timing data Tcg and ignition timing data T
Without performing acceleration correction of ig, proceed to the next step 63 and R
The ignition timing data Tig stored in the AM 32 is set in the ignition register 38 as it is. Since the calculation processing time cannot be sufficiently secured at the time of high rotation, the acceleration correction calculation described later is omitted. On the other hand, if the determination result of step 61 is negative (No), the acceleration correction of the ignition timing data Tig and the energization timing data Tcg is performed in step 62 by a known method. The Tig value subjected to such acceleration correction is set in the ignition register 3 in step 63 as described above.
Set to 8.

As is clear from the above description, step 63 is always executed by execution of the interrupt operation processing program INT, so the Tig value data is rewritten each time (FIG. 5 (f)).

Next, in steps 64 and 65, it is determined whether the engine is over rotating. That is, first, in step 64, it is determined whether the stage is the fourth stage. As shown in FIG. 5 (a), the fourth stage is a stage having a crank angle of 90 ° and has an angular interval twice as large as the other stages. During this period, a new interrupt arithmetic processing program INT No execution request occurs. That is,
The program processing time of the fourth stage is twice as long as that of the other stages, and the fourth stage makes it possible to perform the arithmetic processing in the other stages when the rotation speed is high. This is because the crank angle position detection of the present invention has two pulsars 17 and 18 and a reactor 16 projectingly provided on the rotating disk 15 having one cutout on the circumference.
a-16g. Therefore, if the determination result of step 64 is negative (No), it is determined that the processing time required for the overspeed determination cannot be secured, and the process skips step 65 and proceeds to step 66, while if affirmative (Yes), proceeds to step 65. , Executes the subroutine NECHK.

FIG. 4 shows a flow chart of the subroutine NECHK. In step 651, the Ts ₃ value detected in step 57 of FIG. ₃ (this time the loop is executed immediately after the pulse Pc ₁ of the fourth stage is detected). Since the latest Tsn value detected in the loop this time is P in the third stage
It is a time interval Ts ₃ for generating c ₁ pulses. ) Is the variable value T _N e
Is set as. Discrimination in steps 652 and 654, which will be described later, is executed using this variable value T _N e. In step 652, it is determined whether the engine has exited the overspeed state. That is, this determination is made based on whether or not the engine speed Ne is equal to or lower than a predetermined lower limit speed (for example, 15000 rpm). If the result of this determination is affirmative (Yes), the value 0 is set in the flag CUTFLG and it is stored that the engine has left the overspeed state (step 65).
3). If no, proceed to step 654
It is determined whether the engine is in the overspeed state. That is,
The engine speed Ne is a predetermined upper limit speed (for example, 160
00 rpm) or more, and if the result of this determination is affirmative (Yes), the flag CUTFLG is set to the value 1, and it is stored that the engine is in the overspeed state (step 655) and negative (No). In the case of), this program is terminated without doing anything. It should be noted that the reason why the different determination values of the predetermined upper and lower limit engine speeds are used to determine whether the engine is in the over-rotation state in steps 652 and 654 is to stabilize the engine control.

When the execution of the subroutine NECHK is completed, step 66 of FIG. 5 is executed. This step determines whether or not the flag value CUTFLG set in the above-mentioned subroutine NECHK is equal to the value 1, and the determination result is negative (No).
If so, step 67 and the steps described later are executed, but if the result is affirmative (Yes), that is, if an over-rotation state of the engine is detected, step 67 and the following are not executed and the program ends. Therefore, in the latter case, as will be described later, the energization of the ignition coil is not executed, whereby the ignition of the air-fuel mixture is blocked and the engine is prevented from over-rotating.

In step 67, it is determined whether or not the current detection stage is the energization stage. This determination result is negative (No)
If so, as will be described later, the set value of the energization register 34a and the energization counter 3 started in step 60 described above.
This interrupt processing is ended without executing comparison with the count value T of 4. Therefore, in step 60, the energization counter 34
However, the CPU 22 does not output the energization signal to the first output circuit 24a in the current stage. If the determination result in step 67 is affirmative (Yes), the process proceeds to step 68, and the energization timing data Tcg stored in the RAM 32 is set in the energization register 34a. After the setting, the count value T of the energization counter 34 is compared with the energization timing data Tcg (step 69), and the step is continued until the count value T matches the energization timing data Tcg.
69 is executed repeatedly.

When the count value T exceeds the energization timing data Tcg, the CPU
22 outputs a "1" level to the output terminal 22a and sends an energization signal to the first output circuit 24a to start energization of the primary coil of the first ignition coil 45 (step 70, This program is terminated at (g) and (h) in FIG.

In step 59, the start signal from the CPU 22 causes
When the counter 36 starts counting, the comparator 42 is independent of the CPU 22, and the count value of the counter 36 and the ignition timing data Tig set in the register 38 (see FIG. 5).
(f)) is compared, and when the count value exceeds the ignition timing data Tig, an energization stop signal, that is, an ignition signal is supplied to the first output circuit 24a, and is supplied to the primary coil of the first ignition coil 45. Stop energizing. As a result, a high voltage is generated in the secondary coil, spark discharge is generated in the spark plug 10a, and ignition is performed. Regarding the processing of the energization timing and the ignition timing for the ignition plug 10b on the other cylinder side, only the energization and ignition stages are different, and the rest is almost the same as the above, and therefore the explanation is omitted.

(Effects of the Invention) As described in detail above, according to the electronic ignition control method for an internal combustion engine of the present invention, at least one specific crank angle position among the plurality of predetermined crank angle positions and the specific crank angle position are provided. When the crank angle between the predetermined crank angle positions detected immediately after is detected is set to a value larger than the crank angle between two other predetermined crank angle positions and the specific crank angle position is detected, By detecting the number, a signal for preventing ignition is generated when the detected engine speed is equal to or higher than a predetermined speed, and ignition is prohibited while the blocking signal is generated.
When the engine enters the over-speed region, this can be detected early and the over-speed of the engine can be surely prevented.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electronic ignition device for an internal combustion engine applied to an embodiment of the present invention, and FIGS. 2 to 4 are first diagrams.
2 is a flowchart showing an ignition timing control procedure executed by an electronic control unit (ECU) in FIG. 2, FIG. 2 is a flowchart showing a main routine, and FIG. 3 is an INT of an interrupt processing program for controlling energization timing and ignition timing.
FIG. 4 is a flowchart of a subroutine NECHK for determining the overspeed of the engine, which illustrates in detail the processing contents of step 65 of the interrupt processing program INT of FIG. 3, and FIG. 5 is ignition in the apparatus of FIG. 6 is a timing chart showing a timing of energizing a coil, an ignition timing, and the like. 1 ... Engine, 10a, 10b ... Spark plug, 14
...... Crankshaft, 15 ...... Rotating disk, 16a-16g …… Reactor, 17,18 …… Electromagnetic pickup (pulsar),
22 ... CPU, 24a, 24b ... Output circuit, 34 ...
... energization counter, 36, 37 ... ignition counter, 38,
39 ... Ignition register, 45, 46 ... Ignition coil.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Haruhito Mito 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd.

Claims (1)

[Claims] 1. An electronic ignition control method for detecting a plurality of predetermined crank angle positions of an internal combustion engine, and executing a predetermined arithmetic control process for ignition control each time the predetermined crank angle positions are detected. The crank angle between at least one specific crank angle position of the plurality of predetermined crank angle positions and the predetermined crank angle position detected immediately after the detection of the specific crank angle position is determined as a crank angle between two adjacent predetermined crank angle positions. Is set to a value larger than the crank angle, the engine speed is detected when the specific crank angle position is detected, and a signal for preventing ignition is generated when the detected engine speed is equal to or higher than a predetermined speed. An electronic ignition control method for an internal combustion engine, wherein ignition is prohibited while the blocking signal is generated.