JPH0422741A - Controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To carry out highly stable and reliable control by providing a plurality of pulses in a crank angle reference signal to the ignition cycle of each cylinder and changing over a control reference position according to a timing control region to set the control reference position in a practical control region irrespective of the maximum control position of an internal combustion engine. CONSTITUTION:When a rotary disc 2 of a rotary signal generator 8 is rotated in the direction of arrow, a crank angle reference signal L1 consisting of pulse rows is obtained on the basis of windows 3a1, 3a2. The crank angle reference signal L1 has the first and second pulses P1 and P2 in each ignition cycle of each cylinder and as a whole the number of pulses two times that of cylinders. On the other hand, a cylinder discriminating signal L2 based on the window 3b is generated to have the phase discrepant from the first pulse P1 of a specified cylinder. A microcomputer 10 discriminates the first pulse P1 while discriminating the specified cylinder on the base of a cylinder discriminating signal L2, and discriminates four reference positions B110 deg., B75 deg., B40 deg., and B5 deg. in each cylinder on the basis of the crank angle reference signal L1 to control respective movement timing. That is, a control reference position is changed over according to a plurality of timing control regions.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an internal combustion engine control device that controls each cylinder based on a crank angle reference signal from a rotation signal generator.
In particular, the present invention relates to an internal combustion engine control device that improves the reliability of system control by switching the angular reference position of the practical control range.

1. Prior Art] In general, internal combustion engines applied to automobiles etc. have a plurality of cylinders (for example, 4 cylinders) and a speed of several 1100 rpm to several 1000 rpm.
It is rotationally driven at approximately rpm. In the case of four cylinders, each cylinder is connected to the drive shaft (crankshaft) so that its operating position is out of phase by 1/2 period. Also, 4
In the case of a cycle engine, four cycles of intake, compression, explosion, and exhaust are performed for two rotations of the crankshaft, so each cylinder has a camshaft that controls the drive cycle of each cylinder. ]/The operating positions are connected with a phase shift of 4 cycles.

In such internal combustion engines, in order to electronically control the ignition timing by the igniter and the fuel injection timing by the injector for each cylinder, a crank angle reference signal is generated for each cylinder in synchronization with the rotation of the internal combustion engine. However, it is necessary to identify the operating position of each cylinder based on this crank angle reference signal. Usually, a rotation signal generator that detects the rotation of the camshaft or crankshaft of the internal combustion engine is used as means for generating a crank angle reference signal corresponding to the reference position of each cylinder.

FIG. 4 is a block diagram showing a general internal combustion engine control device. In the figure, (8) is a rotation signal generator that generates a position signal corresponding to each cylinder, and (9) is a rotation signal generator that generates a position signal I-. This is an interface circuit for importing data. The position signal includes a cylinder identification signal and a crank angle reference signal (referred to as f&).

(10) is a microcomputer that takes in the crank angle reference signal I- through the interface circuit (9), processes the position signal I-, and identifies the operating position of each cylinder.
Current application, fuel injection, ignition timing, etc. are determined by timer time control from a predetermined reference position.

FIG. 5 is a perspective view without showing a specific configuration example of a rotation signal generator (8) used in a conventional internal combustion engine control device;
The figure is a circuit diagram showing a position signal generator provided in the rotation signal generator (8).

In FIG. 5, (1) is a rotating shaft that rotates in synchronization with the internal combustion engine; for example, a camshaft that rotates once in synchronization with one period of the four-cycle operation of the internal combustion engine (or one cylinder consisting of it). is connected to.

(2) is a co-rotating disk attached to the rotating shaft (1), and corresponds to the reference position (predetermined crank angle) for each cylinder.
Further, a plurality of slit-shaped windows (3a) and (3b) are provided corresponding to the reference position of the specific cylinder.

Here, a case is shown in which the internal combustion engine has four cylinders, and windows (3a) corresponding to the crank angle reference signal for each cylinder are provided at four locations on the outer periphery. Further, the front end of each window (:(a) with respect to the rotation direction (arrow) corresponds to the first reference position for each cylinder, and the rear end corresponds to the second reference position.On the other hand, The window (3b) corresponding to the cylinder identification signal corresponds to the window (3a) for only a specific cylinder (first cylinder), and
- It is provided at a force point and has a phase difference in the rotational direction with respect to the window (3a).

(4a) and (4b) are a pair of light emitting diodes arranged to face each window (3a) and (3b), respectively, and (5a) and (5b) are from each light emitting diode (4a) and (4b). A pair of photodiodes arranged to receive the output light through windows (3a) and (3b).

These light emitting diodes (4a) and (4b) and
Diodes (5a) and (5b) constitute a two-layer coupler.

In FIG. 6, light emitting diodes (4a) and (4b)
The photodiodes (5a) and (5b) are typically shown as (4) and (5), and only one photocoupler is shown. (6) is an amplifier circuit that amplifies the output signal from the photodiode (5); (7)
is an output 1 transistor of an oven collector (grounded emitter) whose base is connected to the output terminal of the amplifier circuit (6). The collector terminals of the transistors (7) are connected to an interface circuit (9) (see FIG. 4).

Next, the operation of the conventional internal combustion engine control device shown in FIGS. 4 to 6 will be described with reference to the waveform diagram in FIG. 7.

When the rotating shaft (1) and the rotating disk (2) rotate in synchronization with the internal combustion engine, the photodiodes (5a) and (5b) arranged opposite to the windows (3a) and (3b) emit light from the windows (
Corresponding to each of 3a) and (3b), two types of pulse signals are output, rising and falling at the front end and falling at the rear end. This pulse signal becomes a position signal via the amplifier l\8 (6) and the transistor (7), and is input to the microcomputer (10) via the interface circuit #8 (9).

As shown in FIG. 7, the position signal includes a crank angle reference signal L1 called SGT and a cylinder identification signal L2 called SGC.

Among these, the crank angle reference signal L1 obtained based on the window (3a) is set at the first reference position (B75°) and the second reference position (B5°) for each cylinder #1 to #4. This results in multiple inverted pulse trains.

The rise of each pulse (B75°) is the TD of each cylinder.
It indicates the position 75° before C (crank angle O° - top dead center) and serves as the control standard for cylinder operation during normal running.Furthermore, the falling edge (B5°) indicates the position 5° before TDC. This is the bypass ignition timing at startup, etc., when the microcomputer (10) cannot operate.

On the other hand, the cylinder identification signal L obtained based on the window (3b)
2 is a crank angle reference signal L for a specific cylinder, that is, #] cylinder.
, and is used to identify a specific cylinder. The separate signal L2 has a different phase from the crank angle reference signal L2, and in this case, it rises before the rising edge (B75°) of the crank angle reference signal L, and rises before the rising edge (B5°) of the crank angle reference signal L. I'll stand down later.

The operating position of each cylinder identified by the crank angle reference signal L1 is shifted by 1/4 period with respect to one period of the camshaft (corresponding to two periods of the crankshaft, that is, 720°), and 1/2 period (180°
) are shifted by Also, as is well known, each cylinder is #1
The cylinders operate in the order of cylinder #3, cylinder #4, and cylinder #2.

Based on the crank angle reference signal I-7 and the cylinder identification signal L2 obtained in this way, the microcomputer (10
) identifies a specific cylinder, identifies the operating position of each cylinder, and calculates and controls energization start timing, ignition timing, fuel injection, etc. For example, with the first reference position i B 75° as a reference, a timer controls such that energization is started after a predetermined time has elapsed, and ignition is started after a predetermined time has elapsed.

At this time, as the rotational speed of the internal combustion engine increases, the time to reach the target operating position is shortened, so the control reference position is set to B75.
It is preferable for V to advance the angle more than °.

However, in order to advance the first reference position B by 75°, it is necessary to form a long window (3a) on the rotating disk (2), which deteriorates the strength of the rotating disk (2). It ends up. Also, during bypass ignition, the first reference position WB75° is the energization start time, and the second reference position iB5° is the ignition timing, but if the energization time becomes longer due to the advance of the first reference position,
This is not practical because power consumption increases and problems such as heat generation occur. Furthermore, if the control angle from the reference position becomes large, the system will not be able to be stably controlled because it will be greatly affected by disturbances such as rotational fluctuations of the internal combustion engine.

[Problems to be Solved by the Invention] As described above, the conventional internal combustion engine control device generates only one pulse of the crank angle reference signal L+ for each cylinder, so the control #fJ reference position is This poses a problem in that control stability deteriorates due to disturbances such as rotation fluctuations.

This invention was made to solve the above-mentioned problems, and the number of pulses of the crank angle reference signal is set to two for the ignition cycle of one cylinder, and the control reference signal is set according to the timing control region. It is an object of the present invention to provide an internal combustion engine control device in which the reliability and stability of system control are improved by switching positions.

Means for Solving the Problem 1 The internal combustion engine control device according to the present invention is characterized in that the crank angle reference signal is set at a third reference position that is more advanced than the first reference position with respect to the ignition cycle of each cylinder. The microcomputer has a first pulse that is inverted and a second pulse that is inverted at a fourth reference position that is retarded from the first reference position and advanced from the second reference position. The control reference position is switched between the first to fourth reference positions according to the control area.

(1) In this invention, the two pulses for each cylinder included in the crank angle reference signal increase the rising and falling timing edges, and according to the timing control area of cylinder control (energization, ignition, etc.), The first to fourth reference ai' devices are switched to set the control reference a to 17vrf.

(Example) Hereinafter, an example of the present invention will be explained with reference to the drawings.
The figure is a perspective view showing a rotation signal generator used in one embodiment of the present invention, (1), (2), (3b), (4a).
), (4b), (5a) and <5b) are the same as in FIG. Further, the overall configuration of one embodiment of the present invention is as described in the fourth embodiment.
As shown in the figure.

(3a,,) and (3a2) are the crank angle reference signal L1
The preceding window (3ai> with respect to the rotational direction of the rotating disk (2) is a window for generating the crank angle reference point 5).
The following window (3a□) corresponds to the second pulse (4), and the following window (3a□) corresponds to the second pulse. It is as shown in FIGS. 5 and 6, except that a pair of windows (3a, . . . ) and (3a2) are formed corresponding to the windows (3a, . . . ) and (3a2), respectively.

21\1 is a waveform diagram showing the crank angle reference signal I-1 and cylinder identification No. 13 and 2 generated by the rotation signal generator of Fig. 1, and Fig. 3 is a waveform diagram showing the control operation according to the present invention at each reference position. FIG. 3 is an explanatory diagram shown together with a timing control area and a timing control area.

Next, the operation of one embodiment of the present invention will be described with reference to FIGS. 1 to 4.

Similarly to the above, when the rotating disk (2) rotates in the direction of the arrow,
Based on the windows (3a 1) and (3a2), a crank angle reference signal [,l consisting of a pulse train is obtained as shown in FIG. This crank angle reference signal I-1 has a first pulse P and a second pulse P2 corresponding to each ignition cycle of each cylinder, and has a total number of pulses twice as many as the number of cylinders. .

At this time, the first pulse by the window (3a, ))),
is the third reference position fi1311. which is advanced from the first reference position B75°. Stand up at o° and move to the first reference position 1B7
It falls at 5°. Further, the second pulse P2 generated by the window (3a2) is on the retard side and the second
The fourth reference position fiB40 is on the advance side from the reference position B5°.
Stand up at the second reference position B5° and stand at the second reference position B5°.

This creates a third pulse based on the timing edge of each pulse.
reference position B110° and fourth reference position ff B 40
On the other hand, the cylinder identification signal ■-7, based on the window (3b), is out of phase with respect to the [th] pulse Pl of the specific cylinder, and is generated as t,(. 3, the reference position F (rises on the advance side from +10', rises on the retard side from the first reference position iB 75°, and rises -17 on the advance side from the fourth reference position +340°. In this case , the length of window (3b) is
Since it is sufficient to correspond to the lengths a and ), the length is shorter than that of the conventional example shown in FIG.

The microphone l cocomputer (10) receives the cylinder identification signal I-
7° and at the same time identify the first pulse P, and also set the crank angle reference signal 171 as #]
Next, four criteria for each cylinder (Q v? B I I O
o, B75°, 840'' and B5°, and control the respective operation timings.

Specifically, by switching the control reference position according to the timing control regions (a) to (d), the reference position closest to the timing by timer control is set as the control reference position. That is, for the timing control region (a), the third reference position B110° on the most advance side is set as the control reference position, and for the region (b), the first reference position B110° is set as the control reference position.
, for region (c), the fourth criterion (-iff device 40
', and for region (d), the second 21 quasi-position B5° is set as the control reference position. As a result, even if the pulse width of the crank angle reference signal L varies somewhat due to transient operation or the like, there is almost no problem with the control.

For example, when each pulse P and I)2 suddenly fluctuates as shown by the dashed-dotted line (see Figure 3) due to sudden acceleration, a timing edge is detected before reaching the ignition timing under timer control. In order to prevent misfires and the like, "branch control" is executed to immediately ignite the engine.

Also, during normal rotation, the first reference position τB75° is used as the control reference for ignition timing, etc., and during high speed rotation, the third reference position B is used as the reference position.
Let IIO° be the control standard. As a result, even at higher rotational speeds than in the past, a standard for timing control on the advance side is obtained, making it possible to carry out sufficient advance control for starting energization, ignition, etc. Therefore, the reference position of the practical control range can be set without being influenced by the maximum control position of the internal combustion engine, and the control becomes stable.

Also, at the time of initial ignition at the initial stage of startup, the microcomputer (10) cannot function due to a drop in battery voltage due to starter operation, so the second pulse P2
Bypass ignition control is performed according to the following. At this time, energization is started at the fourth reference position B40°, and the energization is started at the second reference position B5°.
By igniting the ignition coil, the pulse duty during bypass ignition is reduced, and the current flowing through the ignition coil is suppressed more than before. Therefore, the thermal load on the power device is reduced and damage caused by heat generation is prevented, so there is no need to install a sink. Also, even if the width of the crank angle corresponding to the energization period is shortened to B40° to B5°,
Since the crankshaft is rotating at a low speed in the initial stage of startup, the energization time is long enough to allow ignition.

In the above embodiment, the first to fourth reference positions are set to B110°, B2S3, B40°, and B5°, respectively, but they can be set to any crank angle as necessary.

Furthermore, it goes without saying that the present invention is applicable not only to the above-mentioned energization and ignition control operations, but also to other control operations such as fuel injection, and provides equivalent effects.

[Effects of the Invention] As described above, according to the present invention, the crank angle reference signal is inverted at the third reference position on the advance side than the first reference position with respect to the ignition cycle of each cylinder. and a second pulse that is inverted at a fourth reference position that is on the retard side of the first reference position and on the advance side of the second reference position. Since the control reference position is switched according to the control position, the control reference position of the practical control range can be set regardless of the maximum control position of the internal combustion engine, and a highly stable and reliable internal combustion engine control system can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a rotation signal generator used in an embodiment of the present invention, FIG. 2 is a waveform diagram showing a crank angle reference signal and a cylinder identification signal generated by an embodiment of the invention, and FIG. FIG. 3 is an explanatory diagram showing a control operation according to an embodiment of the present invention, FIG. 4 is a block diagram showing a general internal combustion engine control device, and FIG. 5 is a rotation signal generator used in a conventional internal combustion engine control device. FIG. 6 is a circuit diagram showing a position signal generation section provided in a general rotation signal generator,
FIG. 7 is a waveform diagram showing a crank angle reference signal and a cylinder identification signal generated in a conventional internal combustion engine control device. (8) Rotation signal generator (10) Microcomputer P1 First pulse P2 Second pulse B75° First reference position B5° Second reference position B 110"...Third reference position B40°...Fourth reference position L,...Crank angle reference signal L2/Cylinder identification signal (a,) to (d)...Timing control area surface, In the figure,
The same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A plurality of cylinders that rotationally drive an internal combustion engine, and a plurality of cylinders that are reversed in correspondence with a first reference position that serves as a control reference for each cylinder and a second reference position that serves as a bypass ignition timing. a rotation signal generator that generates a crank angle reference signal consisting of a pulse train in synchronization with the rotation of the internal combustion engine; a microcomputer that controls the operation of each cylinder based on the first and second reference positions; In the internal combustion engine control device, the crank angle reference signal is a first reference signal that is inverted at a third reference position that is more advanced than the first reference position with respect to the ignition cycle of each cylinder. and a second pulse that is inverted at a fourth reference position that is retarded from the first reference position and advanced from the second reference position, and the microcomputer is configured to perform timing control. An internal combustion engine control device characterized in that the first to fourth reference positions are switched as control reference positions depending on the region.