JPH0422744A - Ignition controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To obtain a highly safe and reliable ignition controller for an internal combustion engine by detecting the ion current which is generated between ignition plugs at every cylinder, and discriminating a specified cylinder based on a logical sum signal of the ion current. CONSTITUTION:At a fixed plate 8 arranged facingly at a part of a rotating disc 5, a standard positioning sensor and a first cylinder discriminating sensors arranged in a face-to-face relation at windows 6, 7 are provided. The standard positioning sensor 9 discriminates a specified cylinder in cooperation with a program inside an ECU 10. In this case, an ion current detector 20 is inserted between a cathode of diode 16 and the ECU 10. A second cylinder discriminating means which discriminates the specified cylinder based on a logical sum signal C of ion current I related to the cylinders controllingly ignited and not ignited is composed of the diode 16 and the ion current detector 20. In a distribution means inside the ECU 10, the respective cylinders are controlled based on a standard positioning signal L1 and a cylinder judging signal L2, or a logical sum signal C and a standard positioning signal L.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a device for controlling ignition of an internal combustion engine such as an automobile gasoline engine, and in particular to an internal combustion engine that can be backed up even if a position signal for cylinder identification fails. This invention relates to an ignition control device.

[Prior Art] -Internal combustion engines used in gasoline engines for automobiles, etc. have a plurality of cylinders (for example, four cylinders) to provide intake air,
It is driven by four cycles: compression, explosion, and exhaust. At this time, in each cylinder, it is necessary to send a spark to the air-fuel mixture compressed by the piston and combust the air-fuel mixture to obtain output, but the pressure generated by combustion acts as an efficient force to push down the piston. It is an important control item to provide a spark of sufficient energy at the optimal rank position to work.

In such an internal combustion engine, a microcomputer electronically performs calculations in order to control the ignition timing by the eveninger of each cylinder, the order of fuel injection by the injector, etc. to R'a.

In order to perform this calculation control, the microcomputer takes in, in addition to various operating conditions, a reference position signal for each cylinder synchronized with the rotation of the internal combustion engine and a cylinder identification signal corresponding to a specific cylinder, and determines the operating position of each cylinder. It identifies and controls at the optimal time. Usually, as means for generating the reference position signal and the cylinder identification signal, a rotation signal generator is used which detects the rotation of the camshaft or crankshaft of the internal combustion engine and generates a synchronization signal.

In addition, at the initial stage of engine startup, before the microcomputer functions, another sensor is used to detect the cylinder groups in the compression stroke and exhaust stroke, and these simultaneous ignition controls are performed, and after the cylinder identification is confirmed, the reference Sequential ignition control is performed based on position signals and cylinder identification signals.

FIG. 3 is a block diagram, not showing, of a conventional internal combustion engine ignition control device for a four-cylinder engine.

In the figure, (1) is a crankshaft serving as a drive shaft of an internal combustion engine, and is connected to pistons of a plurality of cylinders (not shown) to be rotationally driven.

(2) is a camshaft that rotates in synchronization with the crankshaft (1);
(3) is a timing belt that connects the crankshaft (1) and the camshaft (2).

For a typical 4-stroke engine, the crankshaft (1)
Since suction, compression, explosion and exhaust are performed for two revolutions of the camshaft (2) for two revolutions of the crankshaft (1).
rotates once, and the camshaft (2) rotates once in synchronization with one period of the four-cycle operation of each cylinder. or,
In the case of a 4-cylinder engine, the operating position of each cylinder is 1/2 period of one revolution (180°) with respect to the crankshaft (1).
The phase is shifted by 1/1 with respect to the camshaft (2).
The phase is shifted by 4 cycles.

(4) is a rotating shaft of a rotational signal generator connected to the camshaft (2), and (5) is a rotating disk for detecting a reference position provided at one end of the rotating shaft (4). (6) and (7) are slot-shaped windows formed on the rotating disk (5), and the four windows (6) on the outer circumference correspond to the reference position (predetermined rotation angle) for each cylinder. Furthermore, one window (7) on the inner peripheral side is provided so as to correspond only to the window (6) of a specific cylinder.

(8) is a fixed plate disposed opposite to a part of the rotating disk (5), and includes two sets of sensors consisting of photocouplers, namely a reference position sensor W disposed opposite to the window (6) and a fixed plate facing the window (7). ) and a cylinder identification sensor arranged opposite to each other. Here, one end of the window (6) on the front side in the rotation direction corresponds to a first reference position for each cylinder, and one end on the rear side in the rotation direction corresponds to a second reference position for each cylinder. The reference position signal I-1 from the reference position sensor has a pulse waveform that rises at the first reference position and falls at the second reference position. Further, the cylinder identification signal L2 from the cylinder identification sensor is, for example,
The pulse waveform becomes a level "1" in response to the rise of the reference position signal of only the specific cylinder.

Incidentally, each sensor on the rotating disk (5), the windows (6), (7), and the fixed plate (8) constitutes a first cylinder identification means.

Reference numeral (9) denotes another reference position sensor disposed opposite to the crankshaft (]), which constitutes second cylinder identification means.

The reference position sensor (9) is composed of a proximity sensor, a reflective photosensor, or the like, and outputs a reference position signal for the cylinder group every rotation of the crankshaft (1), for example.

(10) is a microcomputer (hereinafter referred to as EC1J) constituting the electronic control device, and it follows the order of cylinders #1 to ## identified by the first or 20th cylinder identifying means.
It includes a distribution means for controlling ignition of four cylinders. E-CU
The distribution means in (10) performs fuel control and control for each cylinder based on the reference position signal L1, cylinder identification signal l-2 (or reference position signal L), and operating condition signals from various sensors (not shown). It is designed to perform ignition control, etc.

(11) is a common emitter power transistor driven by the distribution means in ECU (10), (12) is an ignition coil whose negative order coil is connected to the collector of power j transistor (11), (13) is the ignition coil (12
) are connected to the secondary coils, and these are provided corresponding to each cylinder #1 to #4.

Next, while referring to the timing chart in Figure 4,
The operation of the conventional internal combustion engine ignition control device shown in FIG. 3 will be explained.

When the rotating disk (5) of the rotation signal generator is rotated by the camshaft (2) interlocking with the crankshaft (1), the reference position sensor outputs a reference position signal L1 corresponding to the window (6), and the cylinder The identification sensor outputs a cylinder identification signal L2 corresponding to the window (7).

Normally, the reference position signal L1 called 5GT (crank angle reference signal) rises at a first reference position B75° for each cylinder #1 to #4 and falls at a second reference position B5°. The first reference position B75° indicates a position 75° before the crank angle 0' (TDC - top dead center) for each cylinder, and corresponds to the control reference and the initial energization angle.

Further, the falling reference position B5° (position 5° before TDC) corresponds to the initial ignition angle during cranking.

Also, a cylinder identification signal called SGC is used to identify a specific cylinder (
For example, it is output only when the reference position signal L1 of cylinder #1 is generated.

The reference position signal LI and cylinder identification signal L obtained in this way
2 is input to the ECU (10) together with the operating condition signal. E CtJ (10) distributes the ignition control signal to each identified cylinder, and as is well known, the power transistor (1
1) is turned on to drive the ignition coil (12) and generate a spark at the spark plug (13).

That is, the power transistor (1) is turned on and the secondary coil current of the ignition coil (12) is passed for a required period of time, and then the power transistor (11) is cut off.

As a result, the secondary coil side of the ignition coil (12) is excited, and discharge occurs across the gap of the spark plug (13). Here, the power supply voltage applied to the ignition coil (12) is a negative high voltage, but is cut off after the spark plug (13) is discharged.

On the other hand, at the initial stage of startup, the cylinder identification signal L2 cannot be obtained accurately, so the distributing means in the ECU (10)
Simultaneous ignition control of #1 cylinder and #4 cylinder (or #3 cylinder and #2 cylinder) is performed based on the reference position 1 signal 9'L from the reference position sensor (9). At this time, #1 cylinder and #
The four cylinders rotate one rotation (360°) of the crankshaft (1) to each other.
), and when one cylinder is in the compression stroke, the other is in the exhaust stroke, and even if the ignition of the cylinder in the exhaust stroke is controlled, an explosion will not occur, so there is no particular problem. Also, since the reference position signal I- corresponds to the reference positions of the two cylinders in the compression stroke or the exhaust stroke, the ECU (10) determines the position of the #1 cylinder and the #4 cylinder based on the reference position signal I-. Ignition control of the cylinders (or #3 cylinder and #2 cylinder) can be performed simultaneously.

This simultaneous ignition control is performed for a predetermined time or a predetermined number of rotations, and after the cylinder identification is determined, sequential ignition control is performed based on the X-type position signal L1 and the cylinder identification signal L2.

However, if the signals from the sensors on the fixed plate (8) or L2 fail due to disconnection or short circuit during normal operation, cylinder identification will no longer be possible and highly reliable ignition control cannot be performed. becomes difficult.

In particular, if ignition control is performed on a cylinder during the exhaust stroke or a cylinder during the intake stroke, there is a risk of serious accidents such as engine failure or abnormal explosion.

[Problems to be Solved by the Invention] As described above, the conventional internal combustion engine ignition control device cannot perform cylinder identification when performing simultaneous ignition control, and also cannot identify the reference position signal L1 or the reference position signal L1 during normal operation. Even if the cylinder identification signal L2 fails, it cannot be detected, so there is a problem that safety and reliability cannot be improved.

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to obtain an internal combustion engine ignition control device that is highly safe and reliable.

[Means for Solving the Problems] An internal combustion engine ignition control device according to the present invention includes an ion current detector that detects the ion current generated between the spark plugs of each cylinder, and ignition-controlled cylinders and non-ignition-controlled cylinders. and a third cylinder identification means for identifying the cylinder based on the OR signal of the ionic currents related to the cylinder.

[Operation] The internal combustion engine ignition control device according to the present invention performs simultaneous ignition control at the initial stage of startup and at the time of sensor failure, and also identifies cylinders based on the logical sum signal of ion currents for cylinders whose ignition is controlled and cylinders whose ignition is not controlled. Then, based on the identification result, each cylinder is ignited in a predetermined order.

[Example 1] An example of the present invention will be described below with reference to the drawings. 1st
The figure is a block diagram showing an internal combustion engine ignition control device according to an embodiment of the present invention, and (1) to (13) are the same as described above.

In this case, part of the program of E CU (10) has been changed, and the reference position sensor (9) has changed E CU (1
In cooperation with the program in 0), the cylinders in the compression stroke or exhaust stroke are identified.

(15) is a backflow prevention diode inserted between the ignition coil (12) and the spark plug (13), and (16) is an 8 backflow prevention diode with an anode connected to one end of the spark plug (13). It is a diode.

(20) is the cathode of the diode (16) and the ECU (1
, 0), and a load resistor (16) connected to the cathode of the diode 16).
22), an anode-grounded DC power source 23) connected in series to the load resistor (22), and a voltage dividing resistor connected in parallel to the series circuit consisting of the load resistor (22) and the DC power source (23). (24) and (25), a capacitor (
26) and the voltage dividing resistors (24) and (25) are connected to the comparison input terminal (-), and the output terminal is connected to the ECU
(10) connected to the comparator (27), and the comparator (27) connected in series between the power supply and ground from the intermediate connection point.
) is provided with voltage dividing resistors (28) and (29) for inputting the threshold T I-() to the reference input terminal (+) of the reference input terminal (+).

The diode (16) and the ion current detector (20) are
A third cylinder identification means is configured to identify the cylinder based on the logical phase signal C of the ion current I regarding the cylinder whose ignition is controlled and the cylinder whose ignition is not controlled.

In this case, one of the two comparators (27) #1
OR signal C of ion current I regarding the cylinder and #3 cylinder
The other comparator (27) outputs #4 cylinder and #2 cylinder
It is designed to output a logical sum signal C of the ion currents (■) regarding the cylinders.

Further, the distribution means in the E CU (10) controls each cylinder according to a predetermined cylinder order based on the reference position signal L1 and the cylinder identification signal L2, or based on the OR signal C and the reference position signal. It is supposed to be done.

Next, while referring to the timing chart diagram in Figure 2,
The operation of one embodiment of this invention will be explained. The ignition order during simultaneous ignition control is as shown in the timing chart of FIG.

First, in the initial state, cylinder identification based on the reference position signal L1 and cylinder identification signal L2 is not determined, so cylinders are identified based on the reference position signal L1 and the comparator output signal C (detection result of ion current ■). For example, #1 cylinder and #4 cylinder are identified based on the reference position 1 signal, and a burned cylinder is identified based on the presence or absence of ion current I immediately after ignition control.

At this time, the reference position sensor <9) detects the crankshaft (
1) Since the reference position signal can be obtained every half rotation (180°) and every one rotation (360°), E CU (10)
The system identifies the cylinder groups in the compression stroke and exhaust stroke based on the reference position signal, and can simultaneously control the ignition of two cylinders (for example, #1 cylinder and #4 cylinder) whose phases are different by 180°.

When discharge occurs in the spark plugs (13) of the #1 and #4 cylinders and an explosion (combustion) occurs around the spark plugs (13), immediately after, a large amount of sunlight is generated between the gaps of the spark plugs (13). Ions are generated. These positive ions become ion currents and flow from between the gap of the spark plug (13) through the diode (16) and the load resistor (22), being attracted by the negative voltage of the DC power supply (23).

This ionic current I becomes a voltage across the load resistor (22), and is further converted into a voltage V by the voltage dividing resistors (24) and (25). Then, the voltage ■ representing the logical sum of the ionic currents I for the #1 cylinder and the #4 cylinder is input to the comparison input terminal (-) of one of the comparators (27);
The voltage ■ representing the logical sum of the ionic currents I for the 3rd cylinder and the #2 cylinder is applied to the comparison input terminal (27) of the other comparator (27).
-) is input.

Even if the ignition of the #1 cylinder and #4 cylinder and the #3 cylinder and #2 cylinder are controlled alternately by simultaneous ignition control, in reality,
Since combustion occurs in the order of #1 cylinder, #3 cylinder, #4 cylinder, and #2 cylinder, the voltage corresponding to the ionic current I of each cylinder is ■
occurs in the sequence shown in FIG.

This voltage ■ will have a high value if an explosion occurs, and a low value if no explosion occurs. On the other hand, the reference input terminal (+) of the comparator (27) is connected to the voltage dividing resistor (28) and 29
) is appropriately set in advance by the threshold T H
is entered. Therefore, the comparator (27) detects the voltage V
If the voltage value V is smaller than the threshold TH, the output signal is turned off, and if the voltage value V is greater than or equal to the threshold T8, the output signal is turned on, and only when the ion current I is detected, the OR signal C is generated from the output terminal, and the ECU Enter in (10).

Now, #1 cylinder is in the compression stroke, #1 cylinder and #4 cylinder
Assuming that the cylinders are ignited at the same time, one comparator (
27), due to the combustion of #1 cylinder, immediately after ignition control,
OR signal C based on voltage corresponding to ion current I
(See Figure 2).

Also, if #3 cylinder is in the compression stroke and #3 cylinder and #2 cylinder are ignited at the same time, one comparator (2
7) outputs the OR signal C based on the voltage (■) corresponding to the ion current generator immediately after the ignition control due to the combustion of the #3 cylinder.

As a result, if a logical sum signal is obtained from one of the comparators (27) immediately after the simultaneous ignition control of the #1 and #4 cylinders, the reference position signal corresponds to the #1 cylinder, and the #3 One comparator (
27), it can be seen that the reference position signal corresponds to the #3 cylinder.

Similarly, as shown in the series pattern of the logical phase signal C shown in FIG. 2, two pulses are alternately generated from each comparator (27), and each of #
It can be seen that it is compatible with 2 cylinders. Thereafter, since the operating order of each cylinder is repeated, the cylinder can be identified when the reference position signal I- is obtained.

Therefore, the ECU (10) identifies the cylinder based on the reference position signal and the OR signal C of the ion current I, and the distribution means drives the ignition coil (12) of each cylinder in a predetermined order. A signal can be generated.

Furthermore, since the OR signal C is always input to the ECU (10), the combustion state of each cylinder can be monitored during normal operation. Therefore, even if the reference position signal or cylinder identification signal from the rotation signal generator fails, ignition control can be continued in a predetermined order based on the cylinder identification described above, improving the reliability of ignition control. It won't be damaged.

[Effects of the Invention] As described above, according to the present invention, there is provided an ion current detector that detects the ion current generated between the spark plugs of each cylinder;
A third method for identifying a cylinder based on a logical sum signal of ionic currents regarding the ignition-controlled cylinder and the non-ignition-controlled cylinder.
The cylinder identification means performs simultaneous ignition control at the initial stage of start-up and at the time of sensor failure, and identifies the cylinder based on the logical sum signal of the ion currents for the ignition-controlled cylinder and the non-ignition-controlled cylinder, and the identification result Since the ignition of each cylinder is controlled in a predetermined order based on the above, it is possible to obtain a highly safe and reliable internal combustion engine ignition control system.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, and FIG. 2 is a timing chart 1 to 1 to explain the operation of FIG. 1.
FIG. 3 is a block diagram showing a conventional internal combustion engine ignition control device, and FIG. 4 is a timing diagram showing a general group simultaneous ignition operation. (6, (7)... window (first cylinder identification means) (9...
・Reference position sensor (second cylinder identification means) (10・E
CU (13)...Spark plug (16...
・Diode (20...Ion current detector (16, (20)...Third cylinder identification means L1, L・
・・Reference position signal L, ・・Cylinder identification signal ■・・Ion current C・・OR signal In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] First cylinder identification means for identifying each reference position of a plurality of cylinders whose drive is controlled in synchronization with the rotation of an internal combustion engine; and a cylinder in a compression stroke or an exhaust stroke among the plurality of cylinders. an internal combustion engine ignition control device comprising: second cylinder identification means for identifying a cylinder; and distribution means for controlling ignition of each cylinder according to the cylinder order identified by the first or second cylinder identification means, an ion current detector that detects the ion current generated between the spark plugs of each cylinder; and a third cylinder identification device that identifies the cylinder based on a logical sum signal of the ion currents for the ignition-controlled cylinder and the non-ignition-controlled cylinder. An internal combustion engine ignition control device comprising: means for controlling ignition of each cylinder in a predetermined order using the second and third cylinder identification means.