JP2016053358A - Ignition device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ignition device capable of making an electric apparatus receiving supply of battery voltage from an on-vehicle battery 7, not affected by an operation of an energy charging circuit 5.SOLUTION: An ignition device includes a main ignition circuit 4 generating main ignition by a full transistor operation, and an energy charging circuit 5 charging electric energy from a negative side to a positive side of a primary coil 2a during the main ignition to continue spark discharge. During an operation period of the energy charging circuit 5, a first switch S1 is turned OFF, a second switch S2 is turned ON, and the positive side of the primary coil 2a is switched to earth ground. This eliminates a problem that the battery voltage rises in accompany with an operation of the energy charging circuit 5, and prevents an electric apparatus receiving supply of battery voltage from an on-vehicle battery 7, from causing malfunction and shortening of service life due to the operation of the energy charging circuit 5.SELECTED DRAWING: Figure 1

Description

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

There has been proposed an ignition device that reduces the burden on an ignition plug, suppresses unnecessary power consumption, and continues spark discharge (see, for example, Patent Document 1).
This ignition device is configured by combining a well-known full tiger type ignition circuit and an energy input circuit that starts continuation of the spark discharge during the spark discharge by the ignition circuit.
In the following description, a full-tra type ignition circuit is referred to as a main ignition circuit, and spark discharge by the main ignition circuit is referred to as main ignition.

The energy input circuit inputs electric energy from the negative side of the primary coil to the power supply line of the battery during generation of main ignition by the main ignition circuit. As a result, the “secondary current in the same direction as in the main ignition” is continuously supplied to the secondary coil, and the spark discharge generated by the main ignition is continued for an arbitrary period.
In the following description, a power supply line to which the battery voltage is applied is referred to as a battery voltage line, and a period in which spark discharge is arbitrarily continued by the energy input circuit is referred to as a discharge continuation period.

JP 2014-206068 A

The electrical energy directed to the positive terminal of the in-vehicle battery via the battery voltage line due to the operation of the energy input circuit is due to the "influence of the inductance due to the charging state of the in-vehicle battery", the wiring length to the positive terminal of the in-vehicle battery, etc. There are concerns that affect battery voltage.
Specifically, when electric energy flows toward the positive terminal of the vehicle-mounted battery due to the operation of the energy input circuit, the battery voltage may temporarily increase.

  In addition to the ignition device, a plurality of electrical devices are connected to the plus terminal of the in-vehicle battery. For this reason, when the battery voltage rises due to the effect of the operation of the energy input circuit, a plurality of electrical devices that are supplied with the battery voltage from the in-vehicle battery are affected by the rise of the battery voltage, malfunctioning, shortening the service life, etc. There is a possibility of receiving.

  An object of the present invention is to provide an ignition device for an internal combustion engine that does not affect the operation of an energy input circuit on an electric device that is supplied with a battery voltage from a vehicle-mounted battery.

The ignition device for an internal combustion engine of the present invention employs the means of claim 1. As a result, during the operation period of the energy input circuit, the positive side of the primary coil is switched to earth ground.
For this reason, even if an energy input circuit operates, the malfunction which a battery voltage rises does not arise. As a result, the electric device that receives the battery voltage from the in-vehicle battery is not affected by the operation of the energy input circuit.

It is a schematic block diagram of the ignition device for internal combustion engines. 3 is a time chart for explaining the operation of the internal combustion engine ignition device. It is a schematic block diagram of the ignition device for internal combustion engines. It is a schematic block diagram of the ignition device for internal combustion engines. It is a graph which shows the relationship between a primary voltage, the turns ratio of an ignition coil, and a discharge maintenance voltage. It is a schematic block diagram of the ignition device for internal combustion engines.

  Below, the form for inventing is demonstrated based on drawing. The embodiment disclosed below discloses an example, and it goes without saying that the present invention is not limited to the embodiment.

[Embodiment 1]
The first embodiment will be described with reference to FIGS. 1 and 2.
The ignition device in this embodiment is used for a spark ignition engine for vehicle travel, and ignites an air-fuel mixture in a combustion chamber at a predetermined ignition timing.

A specific example of the engine is disclosed.
The engine is a direct injection engine capable of lean combustion using gasoline as fuel. The engine is also equipped with an EGR device that returns part of the exhaust gas as EGR gas to the engine intake side. Further, the engine includes a swirl flow control means for generating a swirl flow of the air-fuel mixture in the cylinder. The swirl flow is a tumble flow or a swirl flow.
Thus, the engine of this embodiment has an operation region where the ignitability of the air-fuel mixture decreases.

The ignition device in this embodiment is a DI type using an ignition coil 2 corresponding to each ignition plug 1 of each cylinder. DI is an abbreviation for direct ignition.
This ignition device controls energization of the primary coil 2a of the ignition coil 2 on the basis of an ignition signal IGt and a discharge continuation signal IGw given from the ECU 3, which is the center of engine control. Specifically, by controlling energization of the primary coil 2a, the electric energy generated in the secondary coil 2b of the ignition coil 2 is controlled to control the spark discharge of the spark plug 1.

  The ECU 3 generates an ignition signal IGt according to engine parameters (for example, warm-up state, engine speed, engine load, etc.) acquired from various sensors and engine control states (for example, presence or absence of lean combustion, degree of swirl flow, etc.) And a discharge continuation signal IGw is generated and output.

  The ignition device mounted on the vehicle includes a spark plug 1 mounted for each cylinder, an ignition coil 2 mounted for each spark plug 1, a main ignition circuit 4 that performs a full-tra operation, and a continuation of spark discharge. An energy input circuit 5 for performing operation and a control circuit 6 for performing operation control are provided.

  The main parts of the main ignition circuit 4 and the energy input circuit 5 are accommodated in a common case as an ignition circuit unit. The ignition circuit unit is installed in a place different from the ignition plug 1 and the ignition coil 2.

  The spark plug 1 is well known and includes a center electrode connected to one end of the secondary coil 2b and an outer electrode grounded via an engine cylinder head or the like. Then, a spark discharge is generated between the center electrode and the outer electrode by the high voltage applied from the secondary coil 2b.

The ignition coil 2 is a well-known one and includes a primary coil 2a and a secondary coil 2b having a larger number of turns than the number of turns of the primary coil 2a.
One end of the primary coil 2a is on the plus side, and is connected to a battery voltage line α that receives power from the plus terminal of the in-vehicle battery 7.
The other end of the primary coil 2a is a negative side, and is grounded via an ignition switch IGBT (for example, a power transistor, a MOS type FET, a thyristor, etc.) provided in the main ignition circuit 4.

One end of the secondary coil 2b is connected to the center electrode of the spark plug 1 as described above.
The other end of the secondary coil 2b is grounded via a diode 8 and a current detection resistor 9 that suppress the generation of unnecessary secondary voltage when the primary coil 2a is energized.

The main ignition circuit 4 controls the energization of the primary coil 2a to cause the ignition plug 1 to generate main ignition.
Specifically, the control circuit 6 turns on the ignition switch IGBT when the ignition signal IGt is switched to a high signal. Thereby, the primary current i1 flows from the positive side to the negative side of the primary coil 2a.
Further, the control circuit 6 turns off the ignition switch IGBT when the ignition signal IGt is switched to a low signal. As a result, the primary current i1 is cut, a high voltage is generated in the secondary coil 2b, and main ignition occurs in the spark plug 1.

  The energy input circuit 5 inputs electric energy from the minus side to the plus side of the primary coil 2a during the main ignition generated by the operation of the main ignition circuit 4. As a result, the “secondary current i2 in the same direction as in the main ignition” is continuously supplied to the secondary coil 2b, and the spark discharge generated by the operation of the main ignition circuit 4 is continued for an arbitrary discharge duration.

Specifically, the energy input circuit 5 operates in an engine operating region where the ignitability is reduced (for example, during lean combustion, when a strong swirling flow is generated, at a high EGR rate, at a low temperature start, etc.), Continue to increase the ignitability of the mixture.
The energy input circuit 5 includes a booster circuit 11 that boosts the battery voltage and stores the boosted electrical energy.
The energy input circuit 5 is an energy input switch Snet (for example, a MOS FET, a power transistor, etc.) that turns on and off an energy input line β that inputs electric energy stored in the booster circuit 11 to the negative side of the primary coil 2a. Is provided.
The energy input circuit 5 includes a diode 12 that allows current to flow only to the negative side of the primary coil 2a in the energy input line β.

A specific example of the booster circuit 11 is configured by combining a chopper type DC-DC converter that boosts a DC voltage and a power storage unit (for example, a capacitor) that stores boosted electrical energy.
The DC-DC converter is well known. An example of a DC-DC converter is disclosed for the purpose of assisting understanding. The DC-DC converter includes a choke coil to which a battery voltage is applied via a booster circuit power supply line γ. The DC-DC converter includes a step-up switch (for example, a MOS type FET, a power transistor, etc.) for intermittently energizing the choke coil. The DC-DC converter includes a boost oscillation circuit that repeatedly turns a boost switch on and off. The DC-DC converter includes a diode that prevents the electrical energy stored in the power storage means from flowing back to the choke coil side.

The boosting oscillation circuit is controlled by the control circuit 6. Specifically, the boosting oscillation circuit is provided such that the boosting switch is repeatedly turned on and off at a predetermined cycle over a period in which the ignition signal IGt is given from the ECU 3.
The control circuit 6 is provided with a secondary current controller 13 that controls the secondary current i2 by performing ON / OFF control of the energy input switch Snet when the energy input circuit 5 is operated.
A specific example of the secondary current controller 13 will be described. The secondary current controller 13 monitors the secondary current i <b> 2 flowing through the secondary coil 2 b using the current detection resistor 9. The secondary current controller 13 employs feedback control in which the energy input switch Snet is ON / OFF controlled so that the monitored secondary current i2 maintains a predetermined target range.

Note that the secondary current controller 13 is not limited to the feedback control described above. Specifically, the secondary current controller 13 may control the energy input switch Snet on and off by open loop control so that the secondary current i2 maintains a predetermined target range.
Further, the target value of the secondary current i2 when performing feedback control or open loop control may be constant or may be changed according to the operating state of the engine.

The ignition device of this embodiment is provided with switching means for switching the positive side of the primary coil 2a to earth ground when the energy input circuit 5 is operated.
Here, in addition to the battery voltage line α for supplying the battery voltage to the positive side of the primary coil 2a, the ignition device is provided with an earth ground line δ for grounding the positive side of the primary coil 2a. ing.

The switching means includes changeover switch means 14 for switching the positive side of the primary coil 2a to one of the battery voltage line α and the earth ground line δ.
The switching means includes switching control means 15 for controlling the switching switch means 14 to switch the positive side of the primary coil 2a to earth ground when the energy input circuit 5 is operated.

The changeover switch means 14 includes a first changeover switch S1 (for example, a MOS FET, a power transistor, etc.) that intermittently connects the battery voltage line α.
The changeover switch means 14 includes a second changeover switch S2 (for example, a MOS type FET, a power transistor, etc.) that connects and disconnects the earth ground line δ.

The switching control means 15 is provided in the control circuit 6.
The switching control means 15 cuts the battery voltage line α and switches the positive side of the primary coil 2a to earth ground only during the “period immediately before the operation of the energy input circuit 5 and immediately after the operation ends”. In the “other period”, the earth ground line δ is cut and the battery voltage is applied to the positive side of the primary coil 2a.

A specific example of the switching control means 15 is shown in FIG.
The switching control means 15 performs start delay control for switching the second switch S2 from the OFF state to the ON state after switching the first switch S1 from the ON state to the OFF state immediately before the energy input circuit 5 operates. To do.
The switching control means 15 immediately after the operation of the energy input circuit 5 stops, switches the second switch S2 from the ON state to the OFF state, and then switches the first switch S1 from the OFF state to the ON state. Implement control.

That is, when the operation of the energy input circuit 5 is started, the operation is performed in the order of “OFF of the first changeover switch S1” → “ON of the second changeover switch S2” → “Start of ON / OFF control of the energy input switch Snet”.
On the contrary, when the operation of the energy input circuit 5 is finished, the operation is performed in the order of “end of ON / OFF control of the energy input switch Snet” → “OFF of the second changeover switch S2” → “ON of the first changeover switch S1”. .
In addition, the delay time of the switching timing of each switch is set so as to be a short time in a range in which a failure such as a short circuit of the battery voltage does not occur. Specifically, for example, it is set to about several tens of μs.

(Explanation of ignition device operation)
When the ignition signal IGt is output, the ignition switch IGBT is turned on over the output period of the ignition signal IGt, and the booster circuit 11 performs the boosting operation of the battery voltage to store the boosted electrical energy in the power storage means.

  When the ignition signal IGt is stopped, the ignition switch IGBT is turned off and the energized state of the primary coil 2a is cut off. As a result, when the primary current i1 stops, the secondary voltage rises and a high voltage is applied to the spark plug 1 to cause main ignition in the spark plug 1.

After the main ignition is started by the spark plug 1, the secondary current i2 is attenuated in a substantially triangular wave shape. The ECU 3 outputs the discharge continuation signal IGw before the secondary current i2 decreases to a predetermined lower limit current value (that is, a current value for maintaining spark discharge).
Immediately before this, the plus side of the primary coil 2a is switched to earth ground by the operation of the switching means described above.
Specifically, by the start delay control described above, the first changeover switch S1 is turned off to stop the application of the battery voltage to the primary coil 2a, and then the second changeover switch S2 is turned on to turn on the primary coil 2a. Performs switching operation to ground the positive side of the ground.

  When the discharge continuation signal IGw is output, the control circuit 6 activates the energy input circuit 5. Then, the energy input circuit 5 inputs electric energy from the minus side of the primary coil 2a toward the plus side, and continues the spark discharge generated by the operation of the main ignition circuit 4.

Specifically, when the discharge continuation signal IGw is output, the secondary current controller 13 performs ON / OFF control of the energy input switch Snet, and the electric energy stored in the power storage means of the booster circuit 11 is negative of the primary coil 2a. Insert from the side toward the plus side. Then, as indicated by a one-dot chain line arrow Y in FIG. 1, the electric energy that has flowed through the primary coil 2a flows to the ground via the second changeover switch S2.
A diode 16 connected in parallel to the ignition switch IGBT is provided as a means for flowing a reflux current that returns to the first coil 2a again through the earth ground line δ during operation of the energy input circuit 5.

  This will be described more specifically. Every time the energy input switch Snet is turned on, electric energy is added from the minus side to the plus side of the primary coil 2a. As a result, every time electric energy is added, a secondary current i2 in the same direction as that at the time of main ignition is sequentially added to the secondary coil 2b and flows. In this way, the secondary current controller 13 controls the energy input switch Snet to be turned on and off, whereby the secondary current i2 is controlled within a range in which spark discharge can be maintained.

This will be described more specifically. When a spark discharge is caused by a strong air flow generated in the cylinder of the engine, the spark discharge expands, the discharge voltage increases, and the secondary current i2 decreases. When the secondary current i2 decreases from a predetermined value, the energy input switch Snet is turned on by feedback control of the secondary current i2, and the amount of electrical energy is input again to the primary coil 2a. As a result, even if the spark discharge is caused to flow and expand, the secondary current i2 is maintained within a substantially constant range, and the discharge sustaining voltage necessary to maintain the spark discharge can be maintained. Blowing out can be avoided.
On the other hand, when the secondary current i2 increases in the spark discharge, the energy input switch Snet is turned off by feedback control of the secondary current i2. Then, the amount of electrical energy input to the primary coil 2a is reduced, and as a result, the secondary current i2 is kept within a substantially constant range.

Thus, since the spark discharge can be continued during the continuation of the discharge continuation signal IGw, high ignitability can be obtained.
Further, since the secondary current i2 is controlled within a substantially constant range while the spark discharge is continued, the effect of reducing electrode wear due to a large current can be obtained.
Further, by controlling the secondary current i2 within a substantially constant range while the spark discharge is continuing, it is possible to suppress an unnecessary power consumption and obtain an energy saving effect.

When the ignition continuation signal IGw is stopped, the operation of the secondary current controller 13 provided in the control circuit 6 is stopped, and the operation of the energy input circuit 5 is stopped. As a result, the spark discharge continued by energy input is completed.
Immediately after this, the operation of the switching means described above switches to the initial state in which the battery voltage is applied to the positive side of the primary coil 2a.
Specifically, by the end delay control described above, the second changeover switch S2 is turned off to stop the grounding of the positive side of the primary coil 2a, and then the first changeover switch S1 is turned on to turn off the primary coil 2a. A switching operation for applying the battery voltage to the plus side is performed.

(Effect 1 of Embodiment 1)
As described above, the ignition device of the first embodiment switches the plus side of the primary coil 2a to earth ground when the energy input circuit 5 is operated, and flows the electric energy input by the energy input circuit 5 to the earth ground.
Thereby, the malfunction that the battery voltage of the vehicle-mounted battery 7 rises at the time of the operation | movement of the energy input circuit 5 does not arise. For this reason, the malfunction which the electric equipment (specifically vehicle equipment different from an ignition device) which receives supply of a battery voltage from the vehicle-mounted battery 7 receives the operation | movement influence of the energy input circuit 5 does not arise.
In other words, the ignition device according to this embodiment can avoid the concern that an electrical device that receives a battery voltage supplied from the in-vehicle battery 7 is affected by the operation of the energy input circuit 5 to cause malfunction or a decrease in life. Thereby, the reliability of an ignition device can be improved.

(Effect 2 of Embodiment 1)
As described above, the ignition device of the first embodiment switches the plus side of the primary coil 2a to earth ground when the energy input circuit 5 is operated.
For this reason, it becomes possible to set the voltage of the electric energy input to the minus side of the primary coil 2a to be lower by “battery voltage” than the prior art. If a specific numerical example is disclosed for the purpose of assisting understanding, when the “specified battery voltage of the in-vehicle battery 7 is 12V”, the voltage of the electric energy input to the primary coil 2a is set low by “12V”. Is possible.
Thereby, the boost ratio of the booster circuit 11 can be suppressed, and the booster circuit 11 can be reduced in size and cost. That is, it is possible to reduce the size and cost of the ignition device equipped with the energy input circuit 5.

(Effect 3 of Embodiment 1)
In the first embodiment, the changeover switch unit 14 is configured by combining the first changeover switch S1 that interrupts the battery voltage line α and the second changeover switch S2 that interrupts the grounding line δ.
Thus, by using the independent first changeover switch S1 and second changeover switch S2, it becomes possible to freely set the changeover timing of the first changeover switch S1 and the second changeover switch S2.

(Effect 4 of Embodiment 1)
In the first embodiment, immediately before the energy input circuit 5 operates, start delay control is performed to switch the first changeover switch S1 from the ON state to the OFF state, and then change the second changeover switch S2 from the OFF state to the ON state. .
Further, in the first embodiment, immediately after the operation of the energy input circuit 5 is stopped, the second changeover switch S2 is switched from the ON state to the OFF state, and then the first changeover switch S1 is switched from the OFF state to the ON state. Perform end delay control.
Thereby, at the time of the switching operation of the changeover switch means 14, problems such as a battery short-circuit do not occur, and the reliability of the ignition device can be improved.

[Embodiment 2]
A second embodiment will be described with reference to FIG.
In the following embodiments, the same reference numerals as those in the first embodiment indicate the same functional objects. Further, in each of the following embodiments, only a changed part with respect to the first embodiment is disclosed, and a form described in advance is adopted for a part not described.

In the first embodiment, the example in which the booster circuit power supply line γ that supplies the battery voltage to the booster circuit 11 is switched to the earth ground when the energy input circuit 5 is operated has been described.
On the other hand, in the second embodiment, the booster circuit power supply line γ is connected to the vehicle battery 7 side from the first changeover switch S1. That is, an independent switch S3 (for example, a normally closed relay switch or the like) is provided in the booster circuit power supply line γ.

  In the second embodiment, the control circuit 6 is provided with a failure determination means 17 for the energy input circuit 5. The failure determination means 17 turns off the switch S3 when the energy input circuit 5 has failed. As a result, even if the energy input circuit 5 breaks down, only the energy input circuit 5 can be stopped, and the operation of the engine can be continued by the main ignition circuit 4.

[Embodiment 3]
Embodiment 3 is demonstrated based on FIGS. 4-6.
In the energy input circuit 5 of the first embodiment, the electric energy boosted by the booster circuit 11 is input from the negative side of the primary coil 2a toward the positive side, thereby causing a spark generated by the operation of the main ignition circuit 4. An example of continuing discharge was shown.
On the other hand, the energy input circuit 5 of the third embodiment continues the spark discharge generated by the operation of the main ignition circuit 4 by supplying the battery voltage from the minus side to the plus side of the primary coil 2a. It is.

That is, the booster circuit 11 shown in the first and second embodiments is eliminated. And when continuing spark discharge, the same switching control as Embodiment 1 mentioned above is implemented.
Specifically, when the discharge continuation signal IGw is output from the ECU 3, the control circuit 6 turns off the first changeover switch S1 and turns on the second changeover switch S2 to ground the positive side of the primary coil 2a to ground. . In this state, the control circuit 6 performs on-off control of the energy input switch Snet.

  Each time the energy input switch Snet is turned on, the battery voltage is applied to the negative side of the primary coil 2a. Then, every time the energy input switch Snet is turned on, electric energy is added from the minus side to the plus side of the primary coil 2a. And whenever electric energy is added, the secondary current i2 of the same direction as the time of main ignition flows in addition to the secondary coil 2b. Thereby, it is possible to maintain a discharge maintaining voltage necessary for maintaining the discharge, and it is possible to continue the spark discharge generated in the spark plug 1.

In order to continue the spark discharge, it is necessary to generate a predetermined discharge sustaining voltage. The discharge sustaining voltage and the primary voltage of the primary coil 2a have a relationship of 1 / turn ratio of the primary coil 2a and the secondary coil 2b. Inputting energy to the primary coil 2a requires a voltage equal to or higher than the primary voltage corresponding to the discharge sustaining voltage.
FIG. 5 shows the relationship between the primary voltage applied to the primary coil 2a, the winding ratio, and the discharge sustaining voltage.
A solid line A in the figure shows the relationship between the primary voltage and the sustaining voltage at a turn ratio of 60.
The solid line B in the figure shows the relationship between the primary voltage and the discharge sustain voltage at a turn ratio of 80.
The solid line C in the figure shows the relationship between the primary voltage and the discharge sustain voltage at a turn ratio of 100.
A solid line D in the figure shows the relationship between the primary voltage and the sustaining voltage at a turn ratio of 200.
A broken line E in FIG. 5 indicates a battery voltage of 12V, and a broken line F in FIG. 5 indicates a battery voltage of 48V.

In general, if the sustaining voltage is 2 kV or more, the discharge can be maintained.
Moreover, in the case of the in-vehicle battery 7 having a rated voltage of 12V that is generally used, there is a concern that the voltage may be temporarily reduced to 10V due to an electric load.
For this reason, as is clear from FIG. 5, if the turn ratio is 200 or more, even if the battery voltage is lowered to 10V, the discharge sustain voltage required to maintain the spark discharge is generated. Can do. Therefore, in this embodiment, the turn ratio is set to 200 or more.

(Effect 1 of Embodiment 3)
By providing the changeover switch means 14, the booster circuit 11 shown in the first embodiment can be eliminated.
For this reason, it is possible to reduce the size of the ignition device capable of continuing the spark discharge and to reduce the cost.

(Effect 2 of Embodiment 3)
Further, by eliminating the booster circuit 11, the energy input circuit 5 and the control circuit 6 can be reduced in size. For this reason, the energy input circuit 5 and the control circuit 6 which have been installed in a place different from the ignition coil 2 so far are provided in one circuit 20 as shown in FIG. 6, and the circuit 20 is provided for each ignition coil 2. Can be built in.
By incorporating the miniaturized energy input circuit 5 and the control circuit 6 in each ignition coil 2 in this manner, the vehicle mountability of the ignition device capable of continuing the spark discharge can be dramatically improved. .

In addition, the code | symbol IGt1 and code | symbol IGw1 shown in FIG. 6 are the ignition signal IGt and the discharge continuation signal IGw which control the spark discharge of the ignition plug 1 of a 1st cylinder.
Symbols IGt2 and IGw2 shown in FIG. 6 are an ignition signal IGt and a discharge continuation signal IGw for controlling the spark discharge of the spark plug 1 of the second cylinder.
Symbols IGt3 and IGw3 shown in FIG. 6 are an ignition signal IGt and a discharge continuation signal IGw for controlling the spark discharge of the spark plug 1 of the third cylinder.
Symbols IGt4 and IGw4 shown in FIG. 6 are an ignition signal IGt and a discharge continuation signal IGw for controlling the spark discharge of the spark plug 1 of the fourth cylinder.

[Other Embodiments]
In the above-described embodiment, an example in which a semiconductor switch is used as an example of the changeover switch unit 14 has been described. However, the present invention is not limited thereto, and for example, a relay with a mechanical opening / closing operation may be used.

  In the above embodiment, an example in which the ignition device of the present invention is used in a gasoline engine has been shown. However, since ignition of the air-fuel mixture can be improved by continuing spark discharge, an engine using ethanol fuel or mixed fuel is used. It may be applied. Of course, the ignitability may be improved by using an engine in which poor fuel may be used.

  In the above embodiment, an example of improving the ignitability at the time of lean combustion in which the ignitability deteriorates has been described, but since the ignitability can be improved even in a combustion state different from the lean combustion, the lean combustion You may use for the engine which does not perform.

Further, the present invention may be applied to a high EGR engine that returns EGR gas to the downstream side of the intake of the throttle valve to improve ignitability at the time of high EGR when a large amount of EGR gas is returned to the engine.
Similarly, ignitability may be improved at low engine temperatures by continuing spark discharge at low engine temperatures at which ignitability decreases.

  In the above embodiment, an example in which the ignition device of the present invention is used in a direct injection engine that directly injects fuel into a combustion chamber has been described. However, the present invention is not limited to this, and port injection that injects fuel upstream of an intake valve It may be used for a formula engine.

  In the above embodiment, an example in which the ignition device of the present invention is used for an engine that actively generates a swirling flow of an air-fuel mixture in a cylinder and spark discharge due to the swirling flow is avoided is disclosed. You may use for the engine which does not have a control means.

  In the above embodiment, the present invention is applied to a DI type ignition device, but is not limited thereto.

DESCRIPTION OF SYMBOLS 1 Spark plug 2 Ignition coil 2a Primary coil 2b Secondary coil 4 Main ignition circuit 5 Energy input circuit 14 Changeover switch means (switching means)
15 Switching control means (switching means) provided in the control circuit

Claims (4)

An ignition coil (2) having a primary coil (2a) and a secondary coil (2b);
A spark plug (1) for performing a spark discharge by a high voltage generated in the secondary coil;
A main ignition circuit (4) for causing a primary current (i1) to flow from the positive side to the negative side of the primary coil and generating a high voltage in the secondary coil by cutting the primary current (i1);
An energy input circuit for continuing the spark discharge generated by the operation of the main ignition circuit by supplying electric energy from the negative side to the positive side of the primary coil during the spark discharge generated by the operation of the main ignition circuit. (5) and
Switching means (14, 15) for switching the positive side of the primary coil to earth ground when the energy input circuit is operated;
An internal combustion engine ignition device. The internal combustion engine ignition device according to claim 1,
This internal combustion engine ignition device is
A battery voltage line (α) for supplying battery voltage to the positive side of the primary coil;
An earth ground line (δ) for grounding the positive side of the primary coil,
The switching means is
Changeover switch means (14) for switching the positive side of the primary coil to one of the battery voltage line or the earth ground line;
An ignition device for an internal combustion engine, comprising: switching control means (15) for controlling the changeover switch means to switch the positive side of the primary coil to earth ground when the energy input circuit is operated. The internal combustion engine ignition device according to claim 2,
The changeover switch means includes
A first changeover switch (S1) for intermittently connecting the battery voltage line;
In combination with the second changeover switch (S2) for intermittently connecting the earth ground line,
The switching control means includes
Immediately before the energy input circuit is activated, after the first changeover switch is switched from the on state to the off state, a start delay control is performed to switch the second changeover switch from the off state to the on state.
Immediately after the operation of the energy input circuit is stopped, after the second switch is switched from the on state to the off state, an end delay control is performed to switch the first switch from the off state to the on state. An ignition device for an internal combustion engine characterized by the above. The internal combustion engine ignition device according to any one of claims 1 to 3,
The internal combustion engine ignition device characterized in that the energy input circuit continues the spark discharge generated by the operation of the main ignition circuit by supplying a battery voltage from the negative side to the positive side of the primary coil. .

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