JP2015200253A - Ignitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of an excessive discharge current at an ignition plug at the finish of discharge, in an ignitor which alternately applies electric energy to an ignition plug from two ignition coils.SOLUTION: An ignitor generates spark discharge by alternately applying electric energy to an ignition plug from two ignition coils, and has first and second switching means and control means. The control means includes first and second energization modes. The first energization mode makes the first and second switching means alternately repeat on-operations. In the second energization mode, an on-time of the first and second switching means is set shorter than an on-time in the first energization mode, and the second energization mode makes the first and second switching means alternately repeat on-operations. By this constitution, it can be prevented that an excessive discharge current is generated at the ignition plug at the finish of discharge.

Description

  The present invention relates to an ignition device used for an internal combustion engine (engine).

  As an ignition device, a technique for supplying electric energy from two ignition coils to a spark plug alternately is known (see, for example, Patent Document 1). According to this technology, the first switching means for turning on / off the energization from the vehicle battery to the primary coil of one ignition coil, and the second switching means for turning on / off the electricity from the vehicle battery to the primary coil of the other ignition coil. With. And the full tiger operation | movement by a 1st, 2nd switching means is repeated alternately. Thereby, it is supposed that the stable discharge state without discharge interruption can be maintained.

(problem)
However, according to the technique of Patent Document 1, as shown in FIG. 4, since the energization to both primary coils is turned off at the end of discharge (t13), the currents Ia1 and Ib1 of both primary coils are cut off. The secondary currents Ia2 and Ib2 generated in the respective secondary coils due to electromagnetic induction due to the superposition of the two overlap, and an excessive discharge current I2 (= Ia2 + Ib2) is generated in the spark plug. For this reason, according to the technique of Patent Document 1, there is a high possibility that damage to the electrode is increased in the spark plug and the electrode is consumed quickly.

JP2012-041912A

  The present invention has been made in view of the above problems, and an object of the present invention is to generate an excessive discharge current in the spark plug at the end of the discharge in an ignition device that alternately applies electric energy to the spark plug from the two ignition coils. Is to prevent it.

The ignition device for an internal combustion engine of the present invention generates spark discharge by applying electric energy to the spark plug alternately from the two ignition coils. The ignition device includes the following first and second switching means and control means.
A 1st switching means turns on and off electricity supply to the primary coil of one ignition coil from a vehicle-mounted battery. The second switching means turns on / off the energization from the vehicle battery to the primary coil of the other ignition coil. Further, the control means gives a control signal to the first and second switching means to control the spark discharge in the spark plug.

  The control means has the following first and second energization modes. In the first energization mode, the first and second switching means are alternately turned on. In the second energization mode, the on period of the first and second switching means is set shorter than the on period in the first energization mode, and the first and second switching means are alternately turned on. Then, the control means executes the first energization mode, and continues to execute the second energization mode after executing the first energization mode.

Thereby, after performing a spark discharge according to the demand of the internal combustion engine by executing the first energization mode, the first and second switching means are alternately turned on in a shorter ON period by executing the second energization mode. Thus, the discharge current can be gradually reduced.
For this reason, in the ignition device that alternately supplies electric energy to the ignition plug from the two ignition coils, it is possible to prevent an excessive discharge current from being generated in the ignition plug at the end of the discharge.

It is a schematic block diagram of the ignition device for internal combustion engines (Example). It is a time chart for demonstrating the action | operation of the ignition device for internal combustion engines (Example). It is a flowchart of the 1st, 2nd electricity supply mode execution of the ignition device for internal combustion engines (Example). It is a time chart of the ignition device for internal combustion engines (conventional example).

  Hereinafter, “DETAILED DESCRIPTION OF THE INVENTION” will be described in detail.

  A specific example (example) of the present invention will be described with reference to the drawings. The following “Example” discloses a specific example, and it goes without saying that the present invention is not limited to the “Example”.

FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine ignition device (hereinafter referred to as an ignition device) according to the present invention.
The ignition device 1 is mounted on a spark ignition engine for running a vehicle, and ignites an air-fuel mixture in a combustion chamber at a predetermined ignition timing. An example of the engine is a direct injection engine capable of lean burn using gasoline as fuel, and a swirl flow control means for generating a swirl flow of an air-fuel mixture such as a tumble flow or a swirl flow in a cylinder. Prepare. The ignition device 1 is controlled so as to maintain a stable discharge state without discharge interruption even in an operation state in which the gas flow rate in the cylinder is high and there is a possibility that the spark discharge is blown out, such as lean burn. Yes.

  The ignition device 1 is a DI (Direct Ignition) type, and generates electric sparks by alternately supplying electric energy from two ignition coils 2a and 2b to one ignition plug 4 of each cylinder.

The two ignition coils 2a and 2b will be described more specifically.
On the primary side of the ignition coils 2 a and 2 b, one terminal of each of the primary coils 5 a and 5 b is connected to the plus side of the in-vehicle battery 8 via the DC-DC boost converter 7.
Note that the negative side of the in-vehicle battery 8 is grounded.

Then, the other terminal of the primary coil 5a is connected to the collector terminal of the switching element 10a, and the other terminal of the primary coil 5b is connected to the collector terminal of the switching element 10b. The emitter terminals of the switching elements 10a and 10b are both grounded.
For this reason, the switching elements 10a and 10b are first switching means and second switching means for turning on and off the energization from the in-vehicle battery 8 to the primary coils 5a and 5b of the ignition coils 2a and 2b, respectively.

On the other hand, on the secondary side of the ignition coils 2a and 2b, as with the primary coils 5a and 5b, one terminal of each of the secondary coils 15a and 15b is connected to the plus side of the in-vehicle battery 8 via the DC-DC boost converter 7. Connected to. The other terminal of the secondary coil 15a is connected to the cathode terminal of the diode 17a, and the other terminal of the secondary coil 15b is connected to the cathode terminal of the diode 17b.
The anode terminal of the diode 17a and the anode terminal of the diode 17b are connected to each other and connected to the electrode on one side of the spark plug 4.
The electrode on the other side of the spark plug 4 is grounded.

An ECU 20 is provided as control means for controlling spark discharge in the spark plug 4.
The ECU 20 receives signals from various sensors that are mounted on the vehicle and detect parameters (such as warm-up state, engine speed, engine load, presence / absence of lean combustion, degree of swirl flow, etc.) indicating the operating state of the engine. .

Further, the ECU 20 stores and holds an input circuit that processes an input signal, a CPU that performs control processing and arithmetic processing related to control of the internal combustion engine based on the input signal, and data and programs necessary for engine control. This is a general configuration including an output circuit that outputs signals necessary for internal combustion engine control based on processing results of various memories and CPUs.
And ECU20 produces | generates and outputs the ignition signal according to the engine parameter acquired from various sensors.

  More specifically, the ECU 20 applies ignition signals Siga and Sigb, which are control signals, to the switching elements 10a and 10b from the energization instruction unit 20a to turn on and off the switching elements 10a and 10b, respectively. The primary currents Ia1 and Ib1 are supplied to or cut off from the coils 5a and 5b.

  In the embodiment, as shown in FIG. 2, in the switching elements 10a and 10b, when the ignition signals Siga and Sigb are at the high level, the primary currents Ia1 and Ib1 flow through the primary coils 5a and 5b, respectively. The primary currents Ia1 and Ib1 are operated so as to be cut off.

When the primary current Ia1 is cut off, a high voltage is generated in the secondary coil 15a of the ignition coil 2a, a discharge is formed in the spark plug 4, and the secondary current Ia2 flows.
Similarly, when the primary current Ib1 is cut off, a high voltage is generated in the secondary coil 15b of the ignition coil 2b, and the discharge is maintained in the spark plug 4 when the secondary current Ib2 flows.
Here, the discharge current I2 generated in the spark plug 4 is the sum of the secondary currents Ia2 and Ib2 of the ignition coils 2a and 2b, respectively, and has a relationship of I2 = Ia2 + Ib2.

  Here, as shown in FIG. 2, Siga and Sigb are set so that when one is at a high level, the other is at a low level, and switching elements 10a and 10b are turned on and off alternately. The primary coils 5a and 5b are alternately energized and ignited to continue the spark discharge.

As shown in FIG. 2, the alternating energization of the primary coils 5 a and 5 b is realized by the first energization mode and the second energization mode which are two energization modes of the ECU 20.
The first energization mode is an energization mode in which an on period that is executed according to the operating state of the engine is set and is generally performed conventionally.
The second energization mode is an energization mode in which the ON period of the switching elements 10a and 10b is set shorter than the ON period in the first energization mode, and the switching elements 10a and 10b are repeatedly turned on alternately.
The second energization mode is subsequently executed after the execution of the first energization mode.

In addition, as shown in FIG. 1, the discharge maintenance time is calculated by the maintenance time calculation unit 20b of the ECU 20 according to the operating state of the engine. Then, the ON period of the first energization mode is calculated from the discharge maintaining time by the ON period calculation unit 20c of the ECU 20, and the ON period of the second energization mode is set from the on period of the first energization mode.
Note that switching between the first energization mode and the second energization mode is performed by the determination of the progress determination unit 20d.
The ignition signals Siga and Sigb are given from the energization instruction unit 20a to the switching elements 10a and 10b based on the set on period of the first energization mode and the second energization mode.

More specifically, for example, as shown in FIG. 2, the discharge maintaining time set according to the operating state of the engine is equally divided into 13 and the respective periods are alternately set as the ON periods of the switching elements 10a and 10b. Each of these on periods is an on period of the first energization mode.
In the second energization mode, the on period of the switching elements 10a and 10b is set shorter than the on period in the first energization mode.

Here, an example of a specific processing procedure for executing the first and second energization modes of the ECU 20 will be described with reference to the flowchart of FIG.
First, in S100, the ECU 20 determines whether or not it is necessary to alternately energize to give electric energy to the spark plug 4 alternately from the two ignition coils 2a and 2b.
If alternate energization is required, the process proceeds to S110.
When there is no need for alternate energization, the determination in S100 is repeated until the need for alternate energization occurs.

In S110, the sustain time calculation unit 20b sets the discharge sustain time based on the operating state of the internal combustion engine, and the process proceeds to S120.
In S120, the ON period in the first energization mode is set by the ON period calculation unit 20c based on the discharge maintenance time set in S110, and the process proceeds to S130.
In S130, the ON period in the second energization mode is set by the ON period calculation unit 20c. Here, the ON period in the second energization mode is set to be shorter than the ON period in the first energization mode.

Next, in S140, it is determined whether it is an ignition execution timing.
When it is the ignition execution timing, the process proceeds to S150.
If it is not the ignition execution timing, the determination of S140 is repeated until the ignition execution timing.

In S150, the 1st electricity supply mode which gives ignition signal Siga, Sigb to switching element 10a, 10b from the electricity supply instruction | indication part 20a is performed, and it transfers to S160.
In S160, the progress determination unit 20d determines whether or not the discharge maintenance time has elapsed.
If the discharge maintenance time has elapsed, the process proceeds to S170.
If the discharge maintenance time has not elapsed, the first energization mode is performed until the discharge maintenance time has elapsed, and the determination in S160 is repeated.

In S170, the 2nd electricity supply mode which gives ignition signal Siga and Sigb to switching element 10a, 10b from the electricity supply instruction | indication part 20a is performed.
The execution period of the second energization mode is set to a predetermined period by the ECU 20.

[Effects of Examples]
The ignition device 1 of the embodiment includes an ECU 20 that controls a spark discharge in the spark plug 4 by giving a control signal to the switching elements 10a and 10b.
The ECU 20 has the following first and second energization modes.

In the first energization mode, the switching elements 10a and 10b are alternately turned on.
In the second energization mode, the ON period of the switching elements 10a and 10b is set shorter than the ON period in the first energization mode, and the switching elements 10a and 10b are repeatedly turned on alternately.
Then, the ECU 20 executes the first energization mode, and continues to execute the second energization mode after executing the first energization mode.

Thereby, after performing the spark discharge according to the request | requirement of an internal combustion engine by execution of the 1st electricity supply mode, by switching on the switching elements 10a and 10b alternately by a shorter ON period by execution of the 2nd electricity supply mode. Both Ia2 and Ib2 can be gradually decreased gradually in the second energization mode section, and the discharge current I2 which is the sum of both can be gradually decreased.
For this reason, in the ignition device 1 that alternately supplies electric energy to the ignition plug 4 from the two ignition coils 2a and 2b, the primary currents Ia1 and Ib1 when the two ignition coils 2a and 2b are simultaneously turned off at the end of the discharge are reduced. Thus, the secondary currents Ia2 and Ib2 can be reduced, and an excessive discharge current can be prevented from being generated in the spark plug 4.

[Modification]
In this embodiment, in the second energization mode, when one of the ignition signals Siga and Sigb is at a high level, the other is at a low level and alternately repeats a high level and a low level. The period at the level and the period at the low level were equal, but this is not an issue.
The on period in the second energization mode only needs to be shorter than the on period in the first energization mode. For example, in the respective ignition signals Siga and Sigb, the second energization mode is such that the period at the high level gradually decreases. The on-period may be set. Furthermore, the period at the high level may be reduced stepwise. In these cases, the periods during which the ignition signals Siga and Sigb are at a low level may overlap.

In the present embodiment, an example in which the ignition device 1 of the present invention is used for a gasoline engine has been shown, but the present invention may be applied to an engine using ethanol fuel or mixed fuel.
Further, in the present embodiment, an example in which the ignition device 1 of the present invention is used in an engine capable of lean fuel (lean burn) operation is shown, but the present invention is not limited to application to an engine capable of lean combustion, and lean combustion. You may use for the engine which does not perform.

Further, in this embodiment, an example in which the ignition device 1 of the present invention is used for a direct injection engine that directly injects fuel into a combustion chamber has been shown. However, a port that injects fuel to the intake upstream side (inside the intake port) of the intake valve. You may use for an injection type engine.
Further, in the present embodiment, an example in which the ignition device 1 of the present invention is used for an engine that actively generates a swirling flow (such as a tumble flow or a swirl flow) of an air-fuel mixture in a cylinder is disclosed. You may use for the engine which does not have (a tumble flow control valve, a swallow flow control valve, etc.).

  In the present embodiment, the present invention is applied to the DI type ignition device 1, but a distributor type that distributes the secondary voltage to each spark plug 4 and a single cylinder engine that does not require the distribution of the secondary voltage. The present invention may be applied to the ignition device 1 (for example, a motorcycle or the like).

DESCRIPTION OF SYMBOLS 1 Ignition device 2a, 2b Ignition coil 4 Spark plug 5a, 5b Primary coil
10a Switching element (first switching means)
10b Switching element (second switching means)
20 ECU (control means) Siga, Sigb Ignition signal (control signal)

Claims (1)

In an internal combustion engine ignition device (1) that generates spark discharge by alternately supplying electric energy to an ignition plug (4) from two ignition coils (2a, 2b),
A first switching means (10a) for turning on / off energization from the in-vehicle battery (8) to the primary coil (5a) of one ignition coil (2a);
A second switching means (10b) for turning on and off energization from the vehicle battery (8) to the primary coil (5b) of the other ignition coil (2b);
Control means (20) for providing a control signal (Siga, Sigb) to the first and second switching means (10a, 10b) to control spark discharge in the spark plug (4);
This control means (20)
A first energization mode in which the first and second switching means (10a, 10b) are alternately turned on;
The ON period of the first and second switching means (10a, 10b) is set shorter than the ON period in the first energization mode, and the first and second switching means (10a, 10b) are repeatedly turned on alternately. A second energization mode
The ignition device (1), wherein the first energization mode is executed, and the second energization mode is continuously executed after the first energization mode is executed.

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