JPH051654A - Ignition control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To assume periodic measurement electronic lead angle control with high accuracy by obtaining the correction reference position with high accuracy by means of cylinder discriminating signals, reference signals and pulse signals, and thereby assuming ignition timing control. CONSTITUTION:A microcomputer 5A obtains a third and a fourth reference signal which have been corrected with respect to the correction reference position as a starting point, based on the cylinder discriminating signal SC and the reference position signal SC and the reference position signal ST from respective signal generators 1 and 2 set on a cam shaft, and also based on the pulse signal P from a pulse signal 6 generator set on a crank shaft, ignition control and other control are made with high accuracy based on the aforesaid signals. In this case, the wave form of the correction reference position signal inputted into the microcomputer 5A does neither require to change operation processing within the microcomputer 5A, nor incur an increase in cost.

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 the ignition timing (energization and interruption of an ignition coil) of each cylinder based on a reference position signal synchronized with the 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 crankshaft, 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. 3 is a block diagram showing a conventional internal combustion engine ignition control apparatus. In the figure, 1 is a camshaft (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.
A reference position signal generator 3 and 4 for processing and sending the cylinder identification signal SC and the reference position signal ST respectively, and 5 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 cam shaft, arc-shaped slits corresponding to a predetermined crank angle are provided as reference positions 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. 4 is a waveform diagram showing an example of the cylinder identification signal SC and the reference position signal ST, and shows a case where they are generated for four cylinders consisting 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. 3 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 reference position B5 ° or B75 °, the ignition timing and the fuel injection control position are controlled by the timer control so as to be optimum according to the operating state at that time (the internal combustion engine speed, load, etc.). To decide.

For example, the ignition timing is controlled to the retard side during low speed (low load) operation, and the ignition timing is controlled to advance (electronic advance) during high speed (high load) operation. Also, in the unstable control region such as the initial start-up of the internal combustion engine, for each cylinder,
The second reference position B75 ° is the forced energization start timing, and the first reference position B5 ° is the forced ignition timing. As a result, the energization time is secured to obtain the discharge energy enough to cause explosive combustion in the cylinder, and an explosion occurs at the timing when a predetermined torque is generated 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 shaft provided with Nos. 2 and 2 is not necessarily synchronized with the rotation of the crank shaft with certainty, 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 rotates twice for each cycle of each cylinder. However, since it corresponds to two cylinders at the same time, it is necessary to separately provide a cylinder identifying means.

[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 accuracy.

The present invention has been made to solve the above problems, and an internal combustion engine ignition control device capable of performing highly accurate cycle measurement electronic advance control by detecting an accurate correction reference position. Aim to get.

[0011]

An internal combustion engine ignition control apparatus according to the present invention includes a pulse signal generator provided on a crankshaft for generating a pulse signal having a constant crank angle pitch, and a first reference position. A counter that counts pulse signals from a corresponding correction reference position as a starting point to generate a correction reference position signal, and a microcomputer that arithmetically controls the ignition timing for each cylinder based on the cylinder identification signal, the reference position signal, and the correction reference position signal. It is equipped with.

[0012]

According to the present invention, the cylinder identification signal and the reference position signal from each signal generator installed on the cam shaft and the pulse signal from the pulse signal generator installed on the crank shaft are used for highly accurate correction. A reference position is obtained, and ignition timing control is performed based on the corrected reference position signal with the corrected reference position as a starting point.

Further, in the present invention, the microcomputer obtains the corrected third and fourth reference positions corresponding to the first and second reference positions from the corrected reference position in the stable operation area. , The preset count values corresponding to the third and fourth reference positions are preset in the counter, and the ignition timing of each cylinder is arithmetically controlled based on the third and fourth reference positions indicated by the corrected reference position signal.

[0014]

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 is a pulse signal generator provided on the crankshaft for generating a pulse signal P having a constant crank angle pitch, and reference numeral 7 is 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 starting 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 '.

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 correction reference position signal ST 'is generated based on the count value of the pulse signal P counted from the initially set correction reference position θ ₀ as a starting point. The correction reference position θ
₀ is initialized 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 generated.
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 rotation fluctuation is extremely small is reached, the pulse signal P becomes stable. 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 a 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 with the correction reference position θ ₀ as the starting point, so if noise and the like are ignored,
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 ° each, the microcomputer 5A obtains the count value information from the microcomputer.
Stored in the memory of 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 from the corrected reference position θ ₀ as a 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.

Further, 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 the same as the conventional one. This software can also be used, and there is no particular increase in cost.

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.

Although the case of four cylinders has been described as an example, it is needless to say that the invention can be applied to an arbitrary plurality of cylinders of six or more. The fourth reference position is B75 ° '
However, the preset count value can be set to any reference position.

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, and the pulse generated during one rotation of the crankshaft. The number is not limited to 120 pulses.

[0031]

As described above, according to the present invention, a pulse signal generator provided on the crankshaft for generating a pulse signal having a constant crank angle pitch, and a corrected reference position corresponding to the first reference position. A counter for counting the pulse signal from the starting point to generate a correction reference position signal, and a microcomputer for calculating and controlling the ignition timing for each cylinder based on the cylinder identification signal, the reference position signal and the correction reference position signal,
A highly accurate corrected reference position is obtained based on the cylinder identification signal and reference position signal synchronized with the camshaft and the pulse signal synchronized with the crankshaft, and the ignition timing is based on the corrected reference position signal starting from this corrected reference position. Since the control is performed, there is an effect that an internal combustion engine ignition control device capable of highly accurate cycle measurement electronic advance control can be obtained.

Further, according to the present invention, the corrected third reference position in the stable operating region is used as a starting point, and the third and fourth reference positions corrected corresponding to the first and second reference positions are obtained. Count values corresponding to the third and fourth reference positions are preset in the counter, and the third and fourth reference values indicated by the corrected reference position signals are set.
Since the ignition timing of each cylinder is arithmetically controlled on the basis of the reference position, there is an effect that an internal combustion engine ignition control device capable of highly precise cycle measurement electronic advance control can be 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 block diagram showing a conventional internal combustion engine ignition control device.

FIG. 4 is a waveform diagram for explaining the operation of the apparatus of FIG.

[Explanation of symbols]

1 Cylinder identification signal generator 2 Reference position signal generator 5A Microcomputer 6 Pulse signal generator 8 Counter SC Cylinder identification signal ST Reference position signal ST 'Correction reference position signal B5 ° First reference position B75 ° Second reference position B5 ° 'Third reference position B 75 °' Fourth reference position Δθ Pitch θ ₀ Corrected reference position P Pulse signal

Claims (2)

[Claims] 1. An ignition control device for an internal combustion engine having a crankshaft driven by a plurality of cylinders and a camshaft interlocked with the crankshaft, wherein the cylinder identification is provided on the camshaft and generates a cylinder identification signal. A signal generator, and first and second units provided on the cam shaft and corresponding to a predetermined crank angle.
A reference position signal generator for generating a reference position signal indicating the reference position, a pulse signal generator provided on the crankshaft for generating a pulse signal having a constant crank angle pitch, and a first reference position A counter that counts the pulse signals from a corresponding correction reference position as a starting point to generate a correction reference position signal, and an ignition timing for each of the cylinders based on the cylinder identification signal, the reference position signal, and the correction reference position signal. An ignition control device for an internal combustion engine, comprising: 2. The microcomputer obtains corrected third and fourth reference positions corresponding to the first and second reference positions from a corrected reference position in a stable operating region as a starting point, and determines the third and fourth reference positions. The count value corresponding to the fourth reference position is preset in the counter, and the third and fourth values indicated by the corrected reference position signal are set.
2. The internal combustion engine ignition control device according to claim 1, wherein the ignition timing of each cylinder is arithmetically controlled based on the reference position of.