JPH0510232A - Ignition controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To obtain an ignition controller for an internal combustion engine which can the cycle measurement electronic advance angle perform with high precision. CONSTITUTION:An ignition timing controller is equipped with a standard position signal generator 2 which is installed on a cam-shaft and generates a standard position signal ST and a pulse signal generator 6 which is installed on a crankshaft and generates the pulse signal P having a certain crank angle pitch. Further, the controller is equipped with a counter 8 which generates a corrected standard position signal ST' by counting the pulse signals, having the corrected standard position corresponding to the standard position, as starting point, and a microcomputer 5A which calculation- controls the ignition timing for each cylinder on the basis of the standard position signal and the corrected standard position signal. The microcomputer includes a correction means for reflecting the error of the corrected standard position signal for the crank angle to, the control for ignition timing, and generates the corrected standard position signal having the corrected standard position with high precision as starting point. The error included in the corrected standard position signal is reflected to the ignition timing control by the number of pulse signals in one revolution of the crankshaft.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine ignition control device for controlling ignition timing (energization and interruption of an ignition coil) of each cylinder based on a reference position signal synchronized with rotation of a crankshaft, and more particularly to a reference position. The present invention relates to an internal combustion engine ignition control device that realizes high precision signals.

[0002]

2. Description of the Related Art Generally, in an internal combustion engine having a crankshaft driven by a plurality of cylinders and a camshaft interlocked with the crankshafts, the internal combustion engine is controlled in order to control ignition timing and fuel injection of each cylinder. A reference position signal synchronized with the rotation is used. The reference position signal indicates a reference position corresponding to the rotation angle of the crank shaft (hereinafter referred to as the crank angle), and the reference position signal generator is provided on the crank shaft or a cam shaft that is interlocked with the crank shaft.

FIG. 7 is a block diagram showing a conventional ignition control system for an internal combustion engine. In the figure, 1 is a cam shaft (not shown).
A cylinder identification signal generator 2 for generating a cylinder identification signal SC, and a reference position signal ST for indicating a first and second reference position corresponding to a predetermined crank angle on a camshaft.
The reference position signal generators 3 and 4 are interfaces for processing and transmitting the cylinder identification signal SC and the reference position signal ST, respectively, and 5 is for each cylinder based on the cylinder identification signal SC and the reference position signal ST. It is a microcomputer (hereinafter referred to as a microcomputer) that controls the ignition timing.

Normally, the cylinder identification signal generator 1 and the reference position signal generator 2 are provided on a cam shaft which makes one rotation for every two revolutions of the crankshaft, and the cylinder identification corresponding to the reference position for each cylinder. The signal SC and the reference position signal ST are generated. For example, on a disc that rotates integrally with a camshaft, arc-shaped slits corresponding to a predetermined crank angle are provided as the reference position for the number of cylinders, and slits corresponding to specific cylinders are separately provided, and each slit is formed by a photocoupler or the like. The waveform shaping process may be performed after the detection.

FIG. 8 is a waveform diagram showing an example of the cylinder identification signal SC and the reference position signal ST, and shows a case where the cylinder identification signal SC and the reference position signal ST are generated for four cylinders of # 1 to # 4, for example. Here, the cylinder identification signal SC is generated corresponding to the # 1 cylinder and the # 4 cylinder, and the first and second reference positions indicated by the fall and rise of the reference position signal ST are
They are B (before TDC TDC) 5 ° and B 75 °, respectively.

Next, the operation of the conventional internal combustion engine ignition control system shown in FIG. 7 will be described with reference to FIG.
The microcomputer 5 takes in the cylinder identification signal SC and the reference position signal ST from the cylinder identification signal generator 1 and the reference position signal generator 2 via the interfaces 3 and 4, and outputs the first reference position B5 for each cylinder. ° and second reference position B 75 °
To detect. Then, with reference to each of the reference positions B5 ° or B75 °, the ignition timing and the fuel injection control position are controlled by the timer control so as to be optimal according to the operating state at that time (the rotation speed and the load of the internal combustion engine). To decide.

For example, during low speed (low load) operation, the ignition timing is controlled to the retard side, and during high speed (high load) operation, the ignition timing is controlled to the advanced side (electronic advance). The actual ignition timing is controlled by the time from the reference position B5 ° or B75 ° using a timer. In the unstable control region such as the initial start-up of the internal combustion engine, the second reference position B is set for each cylinder.
The forced energization start timing is 75 °, and the first reference position B5 ° is the forced ignition timing. This secures the energization time to obtain the discharge energy enough to cause explosive combustion in the cylinder, and also causes an explosion at the timing of generating a predetermined torque according to the operating region, ensuring a minimum internal combustion engine operation. To be done.

However, since the crank shaft and the cam shaft are connected by a timing belt or the like, each signal generator 1
The cam shafts provided with Nos. 2 and 2 are not necessarily in synchronism with the rotation of the crank shaft, and an error occurs in the reference position signal ST. Therefore, it is conceivable to provide the reference position signal generator 2 on the crankshaft, but this is limited due to structural reasons, and one reference position signal pulse is generated because the crankshaft makes two revolutions for each cycle of each cylinder. However, since it corresponds to two cylinders at the same time, it is necessary to provide a cylinder identifying means separately.

[0009]

As described above, the conventional internal combustion engine ignition control device is based on only the reference position signal ST from the reference position signal generator 2 provided on the camshaft.
Also, since the second reference positions B5 ° and B75 ° are detected, there is a problem that an error occurs and the control cannot be performed with high precision.

The present invention has been made in order to solve the above problems, and by detecting an accurate correction reference position and reflecting an error between the correction reference position signal and an actual crank angle, An object of the present invention is to provide an internal combustion engine ignition control device capable of highly accurate cycle measurement electronic advance control.

[0011]

An internal combustion engine ignition control device according to the present invention includes a reference position signal generator provided on a camshaft for generating a reference position signal indicating a reference position corresponding to a predetermined crank angle, A pulse signal generator provided on the crankshaft for generating a pulse signal having a constant crank angle pitch, and a counter for counting pulse signals starting from a correction reference position corresponding to the reference position to generate a correction reference position signal. A microcomputer for calculating and controlling the ignition timing for each cylinder based on the reference position signal and the corrected reference position signal, and the correction means for causing the microcomputer to reflect the error of the corrected reference position signal for the crank angle in the control of the ignition timing. Is included.

[0012]

In the present invention, the reference position signal and the pulse signal corresponding to each rotation of the cam shaft and the crank shaft enable
A correction reference position signal starting from a high-precision correction reference position is generated, and an error included in the correction reference position signal due to the number of pulse signals for one rotation of the crankshaft is reflected in the ignition timing control to be corrected. With this, highly accurate ignition timing control is performed.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention, 5A corresponds to the microcomputer 5, and 1 to 4 are the same as those described above. Reference numeral 6 denotes a pulse signal generator provided on the crankshaft to generate a pulse signal P having a constant crank angle pitch, and reference numeral 7 denotes an interface for processing and transmitting the pulse signal P. The pulse signal generator 6 is composed of, for example, an electromagnetic pickup arranged so as to face the teeth of a ring gear integrated with the crankshaft.

Reference numeral 8 is a counter which counts the pulse signal P from a correction reference position corresponding to the first reference position B5 ° in a stable operation region (described later) to generate a correction reference position signal ST '. , The pulse signal P is applied to the clock input terminal C. Further, the counter 8 receives the pulse signal P when the reference position detection signal D is applied to the enable input terminal PE.
Counting is started, and thereafter, the carry signal is inverted every time when the count value input to the preset input terminal PS is reached and output as the corrected reference position signal ST '.

Reference numeral 9 is an input terminal of the microcomputer 5A and a counter 8
It is a switching circuit connected to the enable input terminal PE of, and in the unstable operation area (at the time of starting, etc.), the reference position signal ST is input to the microcomputer 5A and the stable operation area is provided.
At the time of idling or normal operation, based on the cylinder identification signal SC and the reference position signal ST, the first
The reference position detection signal D corresponding to the reference position B5 ° is input to the enable input terminal PE of the counter 8. The switching circuit 9 may be functionally included in the microcomputer 5A.

In this case, the microcomputer 5A has a function of inputting a predetermined count value to the preset input terminal PS of the counter 8 and a function of switching the switching circuit 9 according to the operating region, and ignition for each cylinder is performed. The timing is bypass-controlled in the unstable operation region based on the cylinder identification signal SC and the reference position signal ST, and is arithmetically controlled in the stable operation region based on the cylinder identification signal SC and the corrected reference position signal ST '. Further, the microcomputer 5A includes a correction means for reflecting the error of the correction reference position signal ST 'with respect to the crank angle in the control of the ignition timing.

FIG. 2 is a waveform diagram for explaining the operation of FIG. Here, the number of teeth of the ring gear is 120, the pitch Δθ of the pulse signal P is 3 °, the third reference position B5 ° 'of the corrected reference position signal ST' to the fourth reference position B of the next cylinder.
The count value up to 75 ° '(corresponding to a crank angle of 110 °) is 37, from the fourth reference position B 75 °' to the third reference position B 5 ° '
The count value (corresponding to a crank angle of 70 °) is set to 23.

The corrected reference position signal ST 'is generated based on the count value of the pulse signal P counted from the initially set corrected reference position θ ₀ . The correction reference position θ
₀ is initially set by the first falling timing of the pulse signal P after detecting the first reference position B5 ° of the specific cylinder (for example, # 1) in the stable operation region.

Next, the operation of the embodiment of the present invention shown in FIG. 1 will be described with reference to FIG. First, in an unstable operating region such as when the engine is started, the rotation signal is large and the pulse signal P that accurately corresponds to the crank angle.
Is not obtained, the counter 8 does not operate and the switching circuit 9
Inputs the reference position signal ST to the microcomputer 5A. Therefore,
The microcomputer 5A performs ignition control based on the cylinder identification signal SC and the reference position signal ST, as in the conventional case.

Next, when the idling operation state is entered and the stable operation region in which the rotational fluctuation is extremely small is reached, the pulse signal P stabilizes. Therefore, in order to make the count value of the pulse signal P correspond to the crank angle, the correction reference position is set. Initialize θ ₀ . That is, when it is determined that the operation area is stable,
The microcomputer 5A switches the switching circuit 9 to the counter 8 side, presets the count value of the counter 8 to 1, and waits for the reference position detection signal D to be input to the counter 8.

The switching circuit 9 generates the reference position detection signal D at the time when the first reference position B5 ° for the specific cylinder is detected and applies it to the enable input terminal PE of the counter 8. As a result, the counter 8 starts counting the pulse signal P applied to the clock input terminal C, but the count value 1
Is preset, the correction reference position signal ST 'is lowered at the first falling timing (correction reference position θ ₀ ) of the pulse signal P.

At the same time, the microcomputer 5A uses the counter 8
And the fourth reference position B75 of the next cylinder.
The count value 37 corresponding to ° 'is applied to the preset input terminal PS of the counter 8. Therefore, the counter 8 receives the correction reference position signal when the count value of the pulse signal P reaches 37 from the correction reference position θ ₀ (that is, the third reference position B5 ° ') to which the reference position detection signal D is input. ST 'is raised to the fourth reference position B75 °'.

Similarly, the microcomputer 5A resets the counter 8 and applies the count value 23 corresponding to the third reference position B5 ° 'to the preset input terminal PS of the counter 8. Therefore, the counter 8 has the fourth reference position B75.
At the time when the count value of the pulse signal P reaches 23 from ° ', the correction reference position signal ST' is lowered and the third reference position B5
° '. Hereinafter, the third and fourth reference positions B5 ° 'and B75
A corrected reference position signal ST 'which is alternately inverted at °' is generated, and is continuously generated even in the normal operation region.

The corrected reference position signal ST 'thus obtained
Is completely synchronized with the rotation of the crankshaft, starting from the correction reference position θ ₀ , so if noise and the like are ignored, the third
Also, no detection error occurs in the fourth reference positions B5 ° 'and B75 °'. Based on the fact that the falling timing of the pulse signal P after the correction reference position θ ₀ corresponds to a crank angle of 3 °, the microcomputer 5A obtains the count value information from the microcomputer.
Stored in the memory within 5A and alternately preset input terminal PS
Output to. Then, the third and fourth reference positions B5 ° '
And B75 ° ', the ignition control of each cylinder is performed.

As described above, the microcomputer 5A has the cylinder identification signal SC and the reference position signal ST from the signal generators 1 and 2 installed on the cam shaft, and the pulse signal generator 6 installed on the crank shaft. The third and fourth reference positions B5 ° 'and B75 °' corrected with the corrected reference position θ ₀ as the starting point are obtained based on the pulse signal P, and high-precision ignition control and other control are performed based on these. It can be performed.

At this time, since the waveform of the corrected reference position signal ST 'input to the microcomputer 5A has the same form as that of the conventional reference position signal ST, it is not necessary to change the arithmetic processing in the microcomputer 5A, and it is different from the conventional one. Similar software can also be used, and there is no particular increase in cost.

However, in FIG. 2, the fourth reference position B75 ° 'by the count value 37 actually corresponds to B74 °, so the correction means in the microcomputer 5A has a crank angle B75 °.
Ignition timing is controlled by an electronic advance angle different from the case where is set to the reference position. When the number of teeth is 120, the count value is 23
There is no error in the third reference position B5 ° 'due to
Since the number of teeth of the ring gear can take any value such as an odd number,
Various errors occur between the third and fourth reference positions and the first and second reference positions. Therefore, the correction means calculates the reference position error according to the number of teeth of the ring gear to perform the calculation correction of the ignition timing.

Next, regarding the correction calculation operation of the ignition timing,
This will be described in detail with reference to FIGS. 3 and 4. FIG. 3 is a waveform diagram showing an error of the corrected reference position signal ST 'with respect to the ideal reference position signal. J, k and m are count values of the pulse signal P from the corrected reference position θ _0, and θ j and θ m are B75. °
Is the third reference position corresponding to B5 °, and T (n) and T (n + 1) are the ignition cycles between consecutive fourth reference positions. The third for the # 1 cylinder
It is assumed that the reference position θ ₀ of B coincides with B5 °. Δθj
Is an error between θj and B75 °, Δθk is an error between θk and B5 °, and Δθm is an error between θm and B75 °, which are values that can be calculated in advance from the number of teeth of the ring gear.

The crank angle distance between each of the reference positions θ ₀ , θj, θk and θm of the corrected reference position signal ST ′ is shown by using the pitch Δθ of the pulse signal P and the count values j, k and m. It is expressed as Also, the ignition cycle T (n)
And the crank angle corresponding to T (n + 1) is 180 ° + (Δθj−Δθm), 180 ° + (Δθm−Δθj) using the respective errors Δθj, Δθk and Δθm, if the advance side is positive. ).

FIG. 4 is a waveform diagram for explaining the ignition timing calculation operation performed by the microcomputer 5A based on the reference positions θj, θk and θm including the errors Δθj, Δθk and Δθm.
_F (n-1) and T _F (n) are the current predicted cycle calculated based on the ignition cycle measured up to the previous time, and θ _A (n-1) and θ _A (n) are # 3 cylinders. And the target cutoff position of the coil current for the # 4 cylinder, that is, the target ignition timing.

Ta ₁ (n-1) and Ta ₂ (n-1) are respectively
Target ignition timing θ with reference to reference positions θj and θk
The control time up to _A (n−1), Ta ₁ (n) and Ta ₂ (n) are the control time up to the target ignition timing θ _A (n) with reference to the reference positions θ m and θ ₀ , respectively. Is. The crank angle distance (k−j) Δθ between the reference positions θj and θk is 70 ° + (Δθj-Δ
θk), the crank angle distance between θm and θ ₀ (180 °
−m · Δθ) is represented by 70 ° + Δθm.

In this case, at the target ignition timing θ _A (n-1), # 3
In order to ignite the cylinder (or # 2 cylinder), the control time Ta ₁ (n−1) or Ta ₂ (n−1) is calculated as follows. Ta ₁ (n−1) = (θj−θ _A ) _TF (n−1) / 180 ° = (B 75 ° + Δθj−θ _A ) _TF (n−1) / 180 ° Ta ₂ (n−1) = (Θk−θ _A ) _TF (n−1) / 180 ° = [B75 ° −θ _A − {70 ° + (Δθj−Δθk)}] _TF (n-1) / 180 °

That is, the crank angle distance from each reference position θj or θk to the target ignition timing θ _A (n−1) is converted into time by the 180 ° prediction cycle T _F (n−1). In order to ignite the # 4 cylinder (or # 1 cylinder) at the target ignition timing θ _A (n), the control time Ta ₁ (n) or Ta ₂ (n) is calculated as follows. _{Ta 1 (n) = (θm} -θ A) T F (n) / 180 ° = (B75 ° + Δθm-θ A) T F (n) / 180 ° Ta 2 (n) = (θ 0 -θ A) _{T F (n) / 180 °} = [B75 ° -θ A - (70 ° + Δθm)] T F (n) / 180 °

That is, the crank angle distance from each reference position θm or θ ₀ to the target ignition timing θ _A (n) is predicted to be 180 ° in the prediction cycle T _F.
Convert to each time according to (n). Thus, for each cylinder, the control time Ta ₁ (n-1) or Ta ₂ (n-1) up to the target ignition timings θ _A (n−1) and θ _A (n) and Ta ₁ ( n) or T
We can find a ₂ (n). At this time, the errors Δθj, Δθk, and Δθm included in the above equations are calculated in advance based on the number of teeth of the ring gear.

In the above embodiment, the correction reference position signal S
Although the reference positions θ ₀ , θj, θk, and θm of T ′ are made to correspond to the waveform of the reference position signal ST, by setting the count value of the pulse signal P arbitrarily, the third position corresponding to an arbitrary crank angle can be obtained. And a fourth reference position can be set.

FIG. 5 is a waveform diagram showing a specific example when the number of teeth N is 125 (odd number). In this case, the pitch Δθ of the pulse signal P is 2.88 °, and if the count values are 42, 20, 43 and 20, respectively, the third reference positions θ ₀ (θd) and θb are B 5 °.
And B6.44 °, and the fourth reference positions θa and θc are B6.
It becomes 4.04 ° and B62.6 °. Therefore, if θc (B62.6 °) is the reference crank angle with zero error, θa is represented by θc + 1.44 °, and θb is represented by θd (B5 °) + 1.44 °. Here, 1.44 ° corresponds to the error.

Next, in order to calculate the control time, the prediction cycle may be used as described above. For example, as shown in FIG. 6, the control for the target ignition timing θ _A based on the previous ignition cycle T is performed. The time T _A may be obtained. That is, # 1 cylinder and #
For 4 cylinders, the previous ignition cycle (θa to θc) is 181.44.
Therefore, the control time T _A is T _A = [(θc−θ _A ) / 180 °] × [(180 ° / 181.44 °) T] = (θ c −θ _A ) T / 181.44 °.

For the # 2 cylinder and the # 3 cylinder, the previous ignition cycle (θc to θa) is 178.56 °, and θa = θc +
Since it is 1.44 °, T _A = [{(θc + 1.44 °) −θ _A } / 180 °] × [(180 ° / 178.56 °) T] = [(θc + 1.44 °) −θ _A ] T / It becomes 178.56 °. In this way, the control time T _A can be calculated for the desired target ignition timing θ _A regardless of the number of teeth N and the reference positions θ a to θ d.

In the above embodiment, the preset reference value of the counter 8 is set to 1 and the corrected reference position θ ₀ is initialized. However, the first fall of the pulse signal P after the reference position detection signal D is generated. Other hardware means of detecting may be used. Further, the case of four cylinders has been described as an example, but it goes without saying that the present invention can be applied to any plurality of cylinders of six or more. Further, although the ring gear is used as the pulse signal generator 6, other means may be used as long as it can generate the similar pulse signal P.

[0040]

As described above, according to the present invention, the camshaft is provided with the reference position signal generator for generating the reference position signal indicating the reference position corresponding to the predetermined crank angle, and the crankshaft. A pulse signal generator that generates a pulse signal having a constant crank angle pitch, a counter that counts the pulse signal from a correction reference position corresponding to the reference position to generate a correction reference position signal, a reference position signal and A microcomputer for calculating and controlling the ignition timing for each cylinder based on the corrected reference position signal, the microcomputer including a correction means for reflecting the error of the corrected reference position signal for the crank angle in the control of the ignition timing, high precision The correction reference position signal is generated starting from the correction reference position of and is included in the correction reference position signal by the number of pulse signals for one rotation of the crankshaft. Since so as to reflect the ignition timing control errors, the effect of the internal combustion engine ignition control apparatus capable of period measurement electronic advancement control precision is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a waveform diagram for explaining the operation of the apparatus of FIG.

FIG. 3 is a waveform diagram for explaining an error at each reference position of the corrected reference position signal according to the present invention.

FIG. 4 is a waveform diagram for specifically explaining the error correction operation in the present invention.

FIG. 5 is a waveform diagram for explaining another specific example of the error correction operation according to the present invention.

FIG. 6 is a waveform diagram for explaining an ignition cycle used for an error correction operation in the present invention.

FIG. 7 is a block diagram showing a conventional internal combustion engine ignition control device.

FIG. 8 is a waveform diagram for explaining the operation of the apparatus of FIG.

[Explanation of symbols]

2 Reference position signal generator 5A Microcomputer 6 Pulse signal generator 8 Counter P pulse signal ST Reference position signal ST 'Correction reference position signal Δθ Pitch θ ₀ Correction reference position θ _A Ignition timing Δθj, Δθk, Δθm Error

Claims (1)

Claim: What is claimed is: 1. An ignition control device for an internal combustion engine, comprising: a crankshaft driven by a plurality of cylinders; and a camshaft interlocked with the crankshaft. A reference position signal generator that generates a reference position signal indicating a reference position corresponding to a crank angle; a pulse signal generator that is provided on the crankshaft and that generates a pulse signal having a constant crank angle pitch; A counter that counts the pulse signal from a correction reference position corresponding to the above to generate a correction reference position signal, and a microcomputer that arithmetically controls the ignition timing for each cylinder based on the reference position signal and the correction reference position signal. And the auxiliary microcomputer for reflecting the error of the correction reference position signal with respect to the crank angle in the control of the ignition timing. An internal combustion engine ignition control apparatus comprising means.