JP7528803B2 - Ignition device control device and program - Google Patents

Description

The present invention relates to a control device and program for an ignition device.

In the ignition system of an internal combustion engine mounted on an automobile, etc., a high voltage is generated by an ignition coil, which generates a spark discharge in the spark plug installed in the internal combustion engine, igniting the mixture in the combustion chamber. In recent years, downsizing and higher compression ratios have led to demands for increased output energy of ignition systems, which has a greater impact on electrode wear of the spark plug. Electrode wear on the spark plug leads to a deterioration in ignition performance and causes problems such as shorter replacement cycles for the spark plug.

Patent Document 1 discloses a configuration that derives the amount of wear on the electrodes of a spark plug caused by the main discharge of single spark ignition and multiple spark ignition based on the engine speed, and corrects the amount of wear based on the number of secondary discharges of multiple spark ignition.

JP 2017-145753 A

However, the technology in Patent Document 1 focuses on estimating the amount of wear on the electrodes of the spark plug, and does not reduce electrode wear on the spark plug.

The present invention was made in consideration of this situation, and aims to reduce electrode wear on spark plugs.

The ignition device control device of the present invention is an ignition device control device that controls an ignition device having an ignition plug installed in an internal combustion engine and an ignition coil that applies voltage to the ignition plug, and is characterized in that it comprises a detection means for detecting the number of re-discharges of the ignition plug, a setting means for setting the current flow time of the ignition coil to be shortened in response to an increase in the number of re-discharges detected by the detection means, and a control means for controlling the ignition coil in accordance with the current flow time set by the setting means.

The present invention makes it possible to reduce electrode wear on spark plugs.

FIG. 2 is a diagram showing a configuration of a control system for an ignition device. FIG. 2 is a diagram illustrating a configuration example of an ignition coil. 4 is a flowchart showing an example of processing performed by a control device of an ignition device. FIG. 11 is a characteristic diagram showing an example of a relationship between time and the product of a secondary voltage and a secondary current. FIG. 4 is a characteristic diagram showing an example of a correction coefficient. 11 is a characteristic diagram showing an example of the change over time in electrode wear between cylinders with and without correction of the energization time of the ignition coil. FIG.

An ignition device control device according to one embodiment of the present invention is an ignition device control device that controls an ignition device having an ignition plug installed in an internal combustion engine and an ignition coil that applies voltage to the ignition plug, and is equipped with a detection means for detecting the number of times the ignition plug re-discharges, a setting means for setting a current flow time of the ignition coil based on the number of times the ignition plug re-discharges detected by the detection means, and a control means for controlling the ignition coil in accordance with the current flow time set by the setting means.
This makes it possible to shorten the time that the ignition coil is energized when the number of re-discharges of the spark plug is high. By shortening the time that the ignition coil is energized, the discharge time of the spark plug is shortened, and the occurrence of re-discharge of the spark plug, which is one cause of electrode wear, can be suppressed, and electrode wear of the spark plug can be suppressed.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a diagram showing the configuration of a control system for an ignition device according to an embodiment.
An ignition device for an internal combustion engine 300 mounted on an automobile or the like includes an ignition plug 100 installed in the internal combustion engine 300 and an ignition coil 200 that applies voltage to the ignition plug 100, and is installed for each of cylinders #1 to #4 of the internal combustion engine 300.

The spark plug 100 has a center electrode 101 and an outer electrode 102 arranged opposite the center electrode 101, and is arranged so that the center electrode 101 and the outer electrode 102 protrude into the combustion chamber 301 of the internal combustion engine 300.

The ignition coil 200 applies a voltage to the spark plug 100. FIG. 2 shows an example of the configuration of the ignition coil 200. The ignition coil 200 includes a primary coil 201 to which power is supplied from a battery VB, which is a power supply source, and a secondary coil 202 connected to the spark plug 100. When the igniter 203 is turned on, the primary coil 201 is energized and a current flows through the primary coil 201. On the other hand, when the igniter 203 is turned off, the primary coil 201 is de-energized and the current to the primary coil 201 is stopped. When the current to the primary coil 201 is stopped, a high voltage is generated in the secondary coil 202 by electromagnetic induction, which generates a spark discharge in the spark plug 100 and ignites the mixture in the combustion chamber 301.

Here, re-discharge, also known as restriking, can occur in the spark plug. There are two types of re-discharge in the spark plug: re-discharge due to the blowing out of the discharge extension (discharge extension is broken and then re-established due to gas flow) and re-discharge due to a short circuit (discharge extension is broken and then re-established). For example, re-discharge can be more likely to occur due to the way gas hits the electrodes 101, 102 in the combustion chamber 301. Such re-discharge is one cause of electrode wear in the spark plug, and electrode wear in the spark plug can be reduced by suppressing the occurrence of re-discharge.

In this embodiment, in order to suppress electrode wear of the spark plug 100, as described below, the energization time of the ignition coil 200 is set based on the number of times the spark plug 100 re-discharges, and the ignition coil 200 is controlled in accordance with the set energization time.
To achieve this control, as shown in FIG. 1, the device includes a control device 1 for the ignition device and a measuring device 2 for measuring the voltage (hereinafter referred to as the secondary voltage) and current (hereinafter referred to as the secondary current) generated in the secondary coil 202 of the ignition coil 200.

The control device 1 includes an input unit 1a, a detection unit 1b, a current-flow time setting unit 1c, and a control unit 1d, and sets the current-flow time of the ignition coil 200 for each cylinder #1 to #4 based on the number of times the ignition plug 100 re-discharges, and controls the ignition coil 200 according to the set current-flow time.

The input unit 1a inputs the secondary voltage and secondary current measured by the measuring device 2.

The detection unit 1b detects the number of re-discharges that occur after the spark discharge of the spark plug 100 based on the secondary voltage and secondary current input by the input unit 1a. When a re-discharge occurs, the electrical energy of the secondary coil 202 increases. Therefore, when the product of the secondary voltage and the secondary current measured by the measuring device 2 after the spark discharge exceeds a predetermined threshold, the detection unit 1b determines that a re-discharge has occurred. The detection unit 1b then counts the number of times that the product of the secondary voltage and the secondary current exceeds the predetermined threshold as the number of times that a re-discharge has occurred. FIG. 4 shows an example of the relationship between time and the product of the secondary voltage and the secondary current when a re-discharge occurs after the spark discharge of the spark plug 100. As shown by peaks 401 to 406, when the product of the secondary voltage and the secondary current exceeds a predetermined threshold 407, it is determined that a re-discharge has occurred. In the illustrated example, six re-discharges have occurred.

The current-flow time setting unit 1c sets the current-flow time of the ignition coil 200 based on the number of re-discharges detected by the detection unit 1b. The current-flow time of the ignition coil 200 is the time during which the igniter 203 is turned ON after a spark discharge is generated in the ignition plug 100 (after the igniter 203 is turned OFF) until the next spark discharge is generated in the ignition plug 100 (after the igniter 203 is turned OFF).

An example of how the energizing time setting unit 1c sets the energizing time will be described.
A reference current supply time corresponding to an operating state is set for the ignition coil 200. For example, a plurality of reference current supply times are defined in a current supply map, and the reference current supply time is read out from the current supply map according to the operating state.
As shown in FIG. 5, a correction coefficient is set to be multiplied by the reference current conduction time. The correction coefficient is set so that the value of the correction coefficient decreases as the number of re-discharges increases, and the current conduction time is set shorter than the reference current conduction time. The current conduction time setting unit 1c determines a correction coefficient based on the number of re-discharges detected by the detection unit 1b, and multiplies the correction coefficient by the reference current conduction time to set the current conduction time. By shortening the current conduction time of the ignition coil 200, the discharge time of the ignition plug 100 is shortened, and the occurrence of re-discharge, which is one of the causes of electrode wear, can be suppressed. Note that the characteristics shown in FIG. 5 are only an example, and it is sufficient that the current conduction time is set to be shorter as the number of re-discharges increases.

The control unit 1d controls the ignition coil 200 according to the energization time set by the energization time setting unit 1c. That is, the control unit 1d turns on/off the igniter 203 of the ignition coil 200 according to the energization time set by the energization time setting unit 1c, and performs energization for the energization time set by the energization time setting unit 1c.

Next, the processing by the control device 1 will be described with reference to FIG. 3. FIG. 3 is a flowchart showing an example of processing by the control device 1. The processing of the flowchart in FIG. 3 is started when the igniter 203 is turned off, that is, when a high voltage is generated in the secondary coil 202 by electromagnetic induction and a spark discharge is generated in the ignition plug 100. For example, when the reference current flow time read from the current flow map changes depending on the operating state, the control device 1 executes the processing of the flowchart in FIG. 3.

In step S1, the input unit 1a inputs the secondary voltage and secondary current measured by the measuring device 2.

In step S2, the detection unit 1b detects the number of re-discharges that occur after the spark discharge of the ignition plug 100 based on the secondary voltage and secondary current input in step S1. As described above, when the product of the secondary voltage and secondary current exceeds a predetermined threshold, the detection unit 1b determines that a re-discharge has occurred and detects the number of re-discharges.

In step S3, the current flow time setting unit 1c sets the current flow time of the ignition coil 200 using the above-mentioned standard current flow time and correction coefficient based on the number of re-discharges detected in step S2.

After the energization time is set in this manner, the control unit 1d controls the ignition coil 200 according to the energization time set in step S3 until a new energization time is set. That is, the control unit 1d turns the igniter 203 of the ignition coil 200 ON/OFF according to the energization time set in step S3, and performs energization for the energization time set by the energization time setting unit 1c.

In the flowchart of FIG. 3, the energization time of the ignition coil 200 is set based on the number of re-discharges after one spark discharge of the ignition plug 100. However, for example, the average value of the number of re-discharges after multiple consecutive spark discharges in time may be calculated, and the energization time of the ignition coil 200 may be set based on the average value.

As described above, the control device 1 sets the energization time of the ignition coil 200 based on the number of re-discharges of the spark plug 100. Specifically, the energization time is set to be shorter as the number of re-discharges increases. The control device 1 then controls the ignition coil 200 in accordance with the set energization time.
This makes it possible to shorten the energization time of the ignition coil 200 in a cylinder in which re-discharge of the spark plug 100 is likely to occur. By shortening the energization time of the ignition coil 200, the discharge time of the spark plug 100 is shortened, and the occurrence of re-discharge, which is one cause of electrode wear, can be suppressed, and electrode wear of the spark plug 100 can be suppressed.

The control device 1 also controls the ignition device for each cylinder. This reduces the variation in electrode wear throughout the internal combustion engine 300. Figure 6 is a characteristic diagram showing an example of the change over time in electrode wear between cylinders with and without correction of the current conduction time of the ignition coil 200. As shown in Figure 6(a), when the current conduction time of the ignition coil 200 is not corrected in each cylinder (the reference current conduction time is left unchanged), the electrode wear of the spark plug 100 varies between cylinders over a long period of operation. In contrast, when the current conduction time of the ignition coil 200 is corrected for each cylinder as in this embodiment, the variation in electrode wear of the spark plug 100 between cylinders is reduced even over a long period of operation.

The control device 1 is configured by a computer device equipped with, for example, a CPU, ROM, RAM, etc., and the functions of the input unit 1a, detection unit 1b, current flow time setting unit 1c, and control unit 1d are realized by the CPU executing a predetermined program stored in, for example, the ROM. For example, the control device 1 may be realized as part of the functions of a control unit mounted on a vehicle.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, each embodiment merely shows a specific example of the implementation of the present invention. The technical scope of the present invention is not limited to each embodiment. Various modifications of the present invention are possible without departing from the spirit of the present invention, and these modifications are also included in the technical scope of the present invention.
The present invention can also be realized by supplying software (programs) to a system or device via a network or various storage media, and having the computer of the system or device read and execute the programs.

1: Control device, 1a: Input unit, 1b: Detection unit, 1c: Current flow time setting unit, 1d: Control unit, 2: Measuring device, 100: Spark plug, 200: Ignition coil, 201: Primary coil, 202: Secondary coil, 203: Igniter, 300: Internal combustion engine

Claims (4)

A control device for an ignition device that controls an ignition device including an ignition plug installed in an internal combustion engine and an ignition coil that applies a voltage to the ignition plug,
A detection means for detecting the number of times the ignition plug is re-discharged;
a setting means for setting a current-carrying time of the ignition coil so as to be shortened in response to an increase in the number of re-discharges detected by the detection means;
and control means for controlling the ignition coil in accordance with the energization time set by the setting means. the ignition device is provided for each cylinder of the internal combustion engine,
2. The ignition device control device according to claim 1, wherein the ignition device is controlled for each of the cylinders. The ignition coil includes a primary coil to which power is supplied from a power supply source and a secondary coil connected to the spark plug, and when the current supply to the primary coil is stopped, a high voltage is generated in the secondary coil, causing a spark discharge in the spark plug.
3. The control device for an ignition device according to claim 1 , wherein the detection means determines that a re-discharge has occurred when a product of the voltage and current generated in the secondary coil exceeds a predetermined threshold value, and detects the number of times that re-discharge has occurred. A program for controlling an ignition device including an ignition plug installed in an internal combustion engine and an ignition coil that applies a voltage to the ignition plug,
A detection means for detecting re-discharge of the spark plug;
a setting means for setting a current-carrying time of the ignition coil so as to be shortened in response to an increase in the number of re-discharges detected by the detection means;
A program for causing a computer to function as a control means for controlling the ignition coil in accordance with the energization time set by the setting means.

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