JP6291984B2 - Ignition device for internal combustion engine - Google Patents

Description

  The present invention relates to an ignition device used for an internal combustion engine (engine), and more particularly to a technique for continuing spark discharge.

A novel ignition device has been devised (not a publicly known technique) as a technique for reducing the burden on the spark plug, suppressing unnecessary power consumption, and continuing spark discharge.
Here, for the purpose of assisting understanding of the background art, a schematic configuration of the new ignition device will be described with reference to FIG. Note that the reference numerals used in FIG. 7 are the same functional elements as those in “Examples” described later.

The ignition device A is equipped with a new energy input circuit 6 in a spark discharge (referred to as main ignition) by a known ignition circuit (referred to as main ignition circuit) to continue the spark discharge.
The energy input circuit 6 is an “energy supply unit” that inputs electric energy from the negative side of the primary coil 3 toward the battery power supply line α during main ignition caused by the operation of the main ignition circuit. By supplying electric energy from the negative side of the coil 3 toward the battery power supply line α, the secondary current is continuously supplied to the secondary coil, and the spark discharge generated by the main ignition is allowed to occur for an arbitrary period (hereinafter, discharge continuation). This is a technique that is continued over a period of time.

The energy input circuit 6 controls the input current input to the primary coil 3 during the discharge continuation period, thereby controlling the secondary current and maintaining the spark discharge. With this technique, it is possible to reduce the burden on the spark plug due to blow-off and re-discharge, and to suppress unnecessary power consumption and to continue the spark discharge.
Hereinafter, the spark discharge continued by the energy input circuit 6 (that is, the spark discharge following the main ignition) is referred to as “continuous spark discharge”.

(problem)
The battery power supply line α branches from the master power supply line α1 in addition to the master power supply line α1 that supplies power from the in-vehicle battery 7 to a plurality of devices (ignition device A, engine control device B, fuel injection device C, etc.). And an ignition power supply line α2 for supplying power to the ignition device A.
The master power supply line α1 is provided with a power supply relay 23 that is linked to an ignition switch 24 that is manually operated by an occupant. When the ignition switch 24 is turned on, the power of the in-vehicle battery 7 is supplied to a plurality of devices (ignition devices). A, engine control device B, fuel injection device C, etc.) (see, for example, Patent Document 1).

Here, it is assumed that an unexpected failure occurs in the energy input circuit 6. Specifically, as shown by arrows X and Y in FIG. 7B, when the energy input circuit 6 fails and the ignition switch 23 is turned OFF, the negative power source of the primary coil 3 is changed to the master power supply line α1. Assume that the electric energy is continuously input.
In this case, there is a possibility that the electric energy boosted by the energy input circuit 6 (voltage higher than the battery voltage) is continuously applied toward the master power supply line α1. Then, the other devices (engine control device B, fuel injection device C, etc.) are continuously affected by the electric energy (overvoltage / overcurrent) applied from the energy input circuit 6 to the master power supply line α1. There is a concern that the engine cannot be stopped due to continued energy input, or that other devices may fail.

In order to avoid this problem, a failure determination means 28 for determining a failure of the energy input circuit 6 is provided, and when the failure determination means 28 determines a failure of the energy input circuit 6, the power supply to the ignition device A is stopped. It is possible to do.
However, when the power supply to the ignition device A is stopped, the ignition device A is stopped, which causes a problem that the engine cannot be operated.

JP 2011-85070 A

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an ignition device for an internal combustion engine that can continue the operation of the engine even if the energy input circuit should fail.

  The internal combustion engine ignition device according to the present invention adopts “Claims 1 and 4 of the Claims”, so that when the abnormality determining means fails, only the energy input power line is disconnected and the energy input circuit is stopped. Let me. As a result, it is possible to avoid the concern that other devices (such as the engine control device and the fuel injection device) will fail due to the continuation of the input energy caused by the failure of the energy input circuit.

  Further, when the energy input circuit fails, only the energy input power line is disconnected, and the ignition power line is not disconnected. For this reason, even if the energy input circuit is stopped, the main ignition circuit can be operated. As described above, even if the energy input circuit breaks down, the operation of the engine can be continued by the main ignition circuit by adopting the present invention.

1 is a schematic configuration diagram of an ignition device for an internal combustion engine (Example 1). 1 is a schematic circuit diagram of an internal combustion engine ignition device (Example 1). FIG. (Example 2) which is a schematic block diagram of the ignition device for internal combustion engines. (Example 2) which shows the relationship between the driving | running state of an engine, and the operating state of an energy input switch. (Example 3) which shows the relationship between a battery voltage and the operating state of an energy input switch. (Example 4) which is a schematic block diagram of the internal combustion engine ignition device. (A) Schematic configuration diagram of internal combustion engine ignition device, (b) explanatory diagram showing the flow of input electric energy (reference example: not known technology).

  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”.

[Example 1]
A first embodiment will be described with reference to FIGS.
The ignition device A according to the first embodiment is used for 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 an engine is a direct injection engine capable of lean burn using gasoline as fuel, equipped with an EGR device that returns a part of the exhaust gas to the engine intake side as EGR gas, and a cylinder A swirling flow control means for generating a swirling flow (tumble flow, swirl flow, etc.) of the air-fuel mixture is provided.

The ignition device A according to the first embodiment is a DI (abbreviation for direct ignition) type that uses an ignition coil 2 corresponding to each ignition plug 1 of each cylinder.
The ignition device A controls energization of the primary coil 3 of the ignition coil 2 based on an instruction signal (an ignition signal IGT and a discharge continuation signal IGW) given from an engine control device (so-called ECU) B that forms the center of engine control. The electric energy generated in the secondary coil 4 of the ignition coil 2 is controlled by energizing the primary coil 3 to control the spark discharge of the spark plug 1.

  The engine control device B includes an ignition signal IGT corresponding to an engine parameter (warm-up state, engine speed, engine load, etc.) acquired from various sensors and an engine control state (existence of lean combustion, degree of swirl flow, etc.) A discharge continuation signal IGW is generated and output.

The ignition device A mounted on the vehicle is
A spark plug 1 mounted for each cylinder;
An ignition coil 2 mounted for each spark plug 1;
A main ignition circuit 5 that performs full tiger operation;
An energy input circuit 6 that performs continuous spark discharge;
It is configured with.

  The main parts of the main ignition circuit 5 and the energy input circuit 6 are housed and arranged in a common case as an “ignition circuit unit”, and are installed in a place different from the spark plug 1 and the ignition coil 2.

  The spark plug 1 is a well-known one, and includes a center electrode connected to one end of the secondary coil 4 and an outer electrode grounded via an engine cylinder head or the like, and is applied from the secondary coil 4. A high voltage causes a spark discharge between the center electrode and the outer electrode.

The ignition coil 2 is a well-known one and includes a primary coil 3 and a secondary coil 4 having a larger number of turns than the number of turns of the primary coil 3.
One end of the primary coil 3 is connected to a battery voltage supply line α that receives power from the positive electrode of the in-vehicle battery 7.
The other end of the primary coil 3 is grounded via an ignition switching means 10 (for example, a power transistor, a MOS transistor, a thyristor, etc.) of the main ignition circuit 5.

One end of the secondary coil 4 is connected to the center electrode of the spark plug 1 as described above.
The other end of the secondary coil 4 is connected to the battery voltage supply line α or grounded. 2 shows that the other end of the secondary coil 4 is grounded via a first diode 11 that suppresses generation of an unnecessary secondary voltage when the primary coil 3 is energized and a current detection resistor 22 described later. This is an example.

  The main ignition circuit 5 performs energization control of the primary coil 3 to cause main ignition in the spark plug 1. Specifically, the main ignition circuit 5 turns on the ignition switching means 10 over the ON period of the ignition signal IGT. When the ignition switching means 10 is turned on, the primary coil 3 of the ignition coil 2 is energized. Is done.

  The energy input circuit 6 supplies secondary energy to the secondary coil 4 by supplying electric energy from the negative side of the primary coil 3 toward the battery voltage supply line α during main ignition caused by the operation of the main ignition circuit 5. The electric current is continuously supplied, and the spark discharge generated by the operation of the main ignition circuit 5 is continued.

Specifically, the energy input circuit 6 continues the spark discharge during the operation state in which the ignitability decreases (during lean combustion, generation of strong swirling flow, high EGR rate, low temperature start, etc.) To improve the ignitability of
A booster circuit 12 that boosts the battery voltage;
An energy input capacitor 13 for storing electrical energy boosted by the booster circuit 12;
An energy input switching means 14 (for example, a MOS transistor, a power transistor, etc.) for turning on and off an energy input line β for inputting electric energy stored in the energy input capacitor 13 to the primary coil 3;
An energy input driver circuit 15 for turning on and off the energy input switching means 14;
A current detection circuit 16 that feedback-controls the ON / OFF state of the energy input switching means 14 based on the secondary current;
A second diode 17 that allows current to flow only from the energy input capacitor 13 to the primary coil 3;
It is configured with.

The booster circuit 12 is a chopper type DC-DC converter that boosts a DC voltage.
A choke coil 18 having one end connected to the battery voltage supply line α,
A step-up switching means 19 (for example, a magnetic field effect transistor, a power transistor, etc.) for intermittently energizing the choke coil 18;
A boosting driver circuit 20 that repeatedly turns this boosting switching means 19 ON and OFF;
A third diode 21 for preventing electrical energy stored in the energy input capacitor 13 from flowing back to the choke coil 18 side;
It is configured with.

  The booster driver circuit 20 is provided so as to repeatedly turn on and off the booster switching means 19 at a predetermined period over a period in which the ignition signal IGT is given.

The current detection circuit 16 feeds back the ON / OFF state of the energy input switching means 14 via the energy input driver circuit 15 so that the secondary current monitored using the current detection resistor 22 maintains a predetermined target range. Control.
The ON / OFF control of the energy input switching means 14 is not limited to feedback control, and the energy input switching means 14 is turned ON / OFF by open loop control so that the secondary current maintains a predetermined target range. It may be controlled. Further, the target value of the secondary current during the continuous spark discharge may be constant, or is changed according to the operating state of the engine (instruction signal (not shown) given from the engine control device B). Also good.

(Description of operation of ignition device A)
When the ignition signal IGT switches from OFF to ON,
(A) While the ignition switching means 10 is turned on over the period in which the ignition signal IGT is output,
(B) During the period when the ignition signal IGT is output, the boosting switching means 19 is repeatedly turned on and off to perform the boosting operation, and the electric energy boosted higher than the battery voltage is stored in the energy input capacitor 13. .

(C) When the ignition signal IGT is switched from ON to OFF, the ignition switching means 10 is turned OFF, and the energized state of the primary coil 3 is suddenly cut off. As a result, the primary voltage rises as soon as the primary current stops. As a result, the secondary voltage rises and a high voltage is applied to the spark plug 1, and main ignition occurs in the spark plug 1.

(D) After the main ignition is started by the spark plug 1, the secondary current is attenuated in a substantially triangular wave shape. And before secondary current falls to a predetermined lower limit current value (current value for maintaining spark discharge), engine control device B outputs discharge continuation signal IGW.
Then, the energy input switching means 14 is ON / OFF controlled by feedback control by the current detection circuit 16, and the electric energy (charge) stored in the energy input capacitor 13 is input to the negative side of the primary coil 3. The electric energy having a voltage higher than the battery voltage stored in the energy input capacitor 13 flows from the negative side of the primary coil 3 toward the battery voltage supply line α.

Specifically, electric energy is added from the negative side of the primary coil 3 toward the battery voltage supply line α every time the energy input switching means 14 is turned on. As a result, every time electric energy is added, a secondary current in the same direction as the secondary current after the main ignition is sequentially added to the secondary coil 4 and flows.
In this way, the current detection circuit 16 performs ON-OFF control of the energy input switching unit 14 so that the secondary current can be continuously maintained to such an extent that spark discharge can be maintained.

This will be specifically described. When a spark discharge is caused to flow by a strong air flow generated in the cylinder of the engine, the spark discharge length is extended, the discharge voltage is increased, and the secondary current is decreased. When the secondary current decreases from a predetermined value, the energy input switching means 14 is turned on by feedback control of the secondary current, and the amount of electric energy is input again to the primary coil 3. As a result, even if the spark discharge is caused to flow and expand, the secondary current is kept substantially constant, the discharge sustaining voltage can be maintained, and the blowout of the spark discharge can be avoided.
Conversely, if the secondary current increases during continuous spark discharge, the energy input switching means 14 is turned OFF by the feedback control of the secondary current, and the amount of electrical energy input to the primary coil 3 is reduced. As a result, the secondary current is kept substantially constant.

  Thus, since the continuous spark discharge can be continued with the same polarity while the discharge continuation signal IGW is continued, high ignitability can be obtained. Further, since the secondary current is controlled to be substantially constant during the continuous spark discharge, the effect of reducing electrode wear due to a large current can be obtained. Furthermore, during continuous spark discharge, the secondary current is controlled to be substantially constant, so that unnecessary power consumption can be suppressed and an energy saving effect can be obtained.

(F) When the ignition continuation signal IGW is switched from ON to OFF, the energy input switching means 14 is turned OFF. As a result, the energy input circuit 6 stops and the continuous spark discharge ends.

(Characteristic technology of Example 1)
The battery voltage supply line α connected to the plus electrode of the in-vehicle battery 7 includes a master power supply line α1 for supplying battery voltage to the ignition device A, the engine control device B, the fuel injection device C, etc.
An ignition power supply line α2 that branches from the master power supply line α1 and supplies the battery voltage to the primary coil 3;
An energy input power line α3 that branches from the master power line α1 and supplies the battery voltage to the energy input circuit 6;
Is provided.
The ignition power supply line α2 and the energy input power supply line α3 are provided independently.

  The master power supply line α1 is switched on and off by the power supply relay 23. The power supply relay 23 is interlocked with an ignition switch 24 operated by an occupant. When the ignition switch 24 is turned on, battery voltage is supplied to the ignition device A, the engine control device B, the fuel injection device C, and the like. Do.

  The energy input power line α3 is a power input unit that receives the battery voltage from the energy input circuit 6. The energy input power line α3 is provided with an energy input switch 25 for switching the ON / OFF state (same as the intermittent state) of the energy input power line α3. The energy input switch 25 is used to supply and cut off electric power to the booster circuit 12, and when the energy input switch 25 is turned off, the boosting operation of the booster circuit 12 is stopped. As a result, the energy input circuit 6 Operation stops.

The energy input switch 25 is provided independently of the power supply relay 23 and is provided to be operable regardless of the power supply relay 23.
As a specific example, the energy input switch 25 of this embodiment is a relay switch that is switched on and off by the engine control device B. The engine control device B is provided to turn off the energy input switch 25 when receiving the abnormality determination signal IGF from the abnormality determination means 26.

Here, the ignition device A according to the first embodiment includes an abnormality determination unit 26 that detects the presence or absence of a failure in the energy input circuit 6.
This abnormality determination means 26 may be provided as a part of the engine control device B, or may be provided independently of the engine control device B.
Although the failure determination technique of the energy input circuit 6 by the abnormality determination unit 26 is not limited, a specific example will be described below for the purpose of assisting understanding.

  The abnormality determination means 26 is provided so as to input a monitor value of the secondary current from the current detection circuit 16 and an instruction value (feedback signal) from the current detection circuit 16 to the energy input driver circuit 15. The abnormality determination means 26 continues to give an instruction to increase the input amount of electric energy from the current detection circuit 16 to the energy input driver circuit 15, but the monitor value of the secondary current does not react in response. In this case, the abnormality of the energy input circuit 6 is determined.

This abnormality determination means 26 forcibly stops the energy input driver circuit 15 and the booster driver circuit 20 and switches the energy input switch 25 to the OFF state when determining the failure of the energy input circuit 6. Specifically, the abnormality determination means 26 outputs an abnormality determination signal IGF and turns off the energy input switch 25 when determining that the energy input circuit 6 has failed.
1 is an instruction signal given to the abnormality determination means 26.

(Effect 1 of Example 1)
As described above, the ignition device A of the first embodiment switches the energy input switch 25 to the OFF state when the abnormality determination unit 26 determines that the energy input circuit 6 has failed. As a result, the power supply to the energy input circuit 6 is cut off, so that the input of electric energy toward the master power supply line α1 via the primary coil 3 and the ignition power supply line α2 is stopped.
In this way, even if the energy input circuit 6 breaks down, it is possible to avoid the problem that electric energy is continuously input. For this reason, it is possible to eliminate the concern that the engine control device B, the fuel injection device C, and the like may fail due to continuation of the input energy.

(Effect 2 of Example 1)
In the ignition device A of the first embodiment, as described above, the energy input switch 25 turns off only the energy input power line α3 when the energy input circuit 6 fails, and the ignition power line α2 does not turn OFF. For this reason, even when the energy input circuit 6 is stopped, the main ignition circuit 5 can be operated. Thereby, even if the energy input circuit 6 breaks down and stops the energy input circuit 6, the operation of the engine can be continued by the main ignition circuit 5. That is, even if the energy input circuit 6 breaks down, the engine can be operated using at least the main ignition circuit 5 to enable the retreat travel.
If the energy input circuit 6 fails and the ignition operation is performed only by the main ignition circuit 5, the super-lean burn operation of the engine is stopped and the ignitability only by the main ignition circuit 5 is ensured. good.

[Example 2]
A second embodiment will be described with reference to FIGS. In the following embodiments, the same reference numerals as those in the first embodiment indicate the same functional objects.
The ignition device A of the second embodiment includes dark current reducing means 27 that switches the energy input switch 25 to the OFF state when the engine operating state exists in a region where the operation of the energy input circuit 6 is stopped. The dark current reducing means 27 is provided as a part of the control program in the engine control apparatus B (not limited).

Specifically, as shown in FIG.
-An area for operating the energy input circuit 6 is an energy supply area D,
-The area where the energy input switch 25 is turned ON is the relay ON area E,
The area where the energy input switch 25 is turned OFF is the relay OFF area F,
In this case, the energy supply area D is provided in a part of the relay ON area E.

(Effect of Example 2)
Thus, by switching the energy input switch 25 to the OFF state in the operation region where the energy input circuit 6 is not operated, power consumption due to dark current can be suppressed.

[Example 3]
Embodiment 3 will be described with reference to FIG.
The ignition device A of the third embodiment includes dark current reducing means 27 that switches the energy input switch 25 to the OFF state when the voltage of the in-vehicle battery 7 is lower than the predetermined voltage V1. This dark current reduction means 27 is provided as a part of the control program in the engine control device B (not limited), as in the second embodiment.

That is, as shown in FIG.
The region where the battery voltage is higher than the predetermined voltage V1 is the relay ON region E,
The area where the battery voltage is lower than the predetermined voltage V1 is the relay OFF area F,
Provided.

(Effect of Example 3)
Thus, when the voltage of the vehicle-mounted battery 7 is lower than the predetermined voltage V1, the power consumption of the ignition device A can be suppressed when the battery voltage decreases by switching the energy input switch 25 to the OFF state.

[Example 4]
Embodiment 4 will be described with reference to FIG.
In the ignition device A of the third embodiment, a fuse 28 is provided on the energy input power line α3. The fuse 28 is a well-known fuse that blows when a current of a predetermined current value or more flows. When the fuse 28 blows, only the energy input power line α3 is switched to a cut state. Specifically, the fuse 28 is provided so as to blow when the energy input circuit 6 fails and the energy input circuit 6 continuously operates.

(Effect of Example 4)
By replacing the energy input switch 25 shown in the first embodiment with the fuse 28 in the fourth embodiment, the effects of the first embodiment can be obtained without increasing the cost and size of the ignition device A. it can.

You may use combining the some Example shown above.
In the above embodiment, an example in which the ignition device A of the present invention is used for a gasoline engine has been shown. However, since the ignition of the air-fuel mixture can be improved by continuous spark discharge, It may be applied. Of course, ignitability can be improved by continuous spark discharge even when used in an engine in which poor fuel may be used.

  In the above embodiment, the ignition device A of the present invention is used in a lean burn engine capable of lean burn (lean burn combustion) operation, and the ignitability at the lean burn where the ignitability is deteriorated is improved by continuous spark discharge. Although shown, it is possible to improve the ignitability by continuous spark discharge even in a combustion state different from lean combustion, so it is not limited to application to lean burn engines, but to engines that do not perform lean combustion It may be used.

Further, the present invention may be applied to a high EGR engine (an engine capable of increasing the return rate of exhaust gas returned to the engine as EGR gas) to generate continuous spark discharge at high EGR, thereby improving ignitability.
Similarly, continuous spark discharge may be performed at a low engine temperature at which the ignitability decreases to improve the ignitability at a low engine temperature.

  In the above embodiment, an example in which the ignition device A of the present invention is used in a direct injection engine that directly injects fuel into a combustion chamber has been described. However, port injection that injects fuel to the intake upstream side (inside the intake port) of the intake valve. It may be used for a formula engine.

  In the above embodiment, the ignition device A of the present invention is used for an engine that actively generates a swirling flow of air-fuel mixture (tumble flow, swirl flow, etc.) in a cylinder, and “spark discharge by swirling flow” is performed by continuous spark discharge. Although an example of avoiding “blow-off” has been disclosed, it may be used for an engine having no swirl flow control means (such as a tumble flow control valve or a swirl flow control valve).

  In the above embodiment, the present invention is applied to the DI type ignition device A. However, the present invention may be applied to the ignition device A of a single cylinder engine (for example, a motorcycle or the like).

  In the above embodiment, an example in which a full tiger is used as an example of the main ignition circuit 5 is shown, but the form of the main ignition circuit 5 is not limited. That is, the main ignition circuit 5 may be a circuit that can perform main ignition by controlling the energization state of the primary coil 3, and may use an ignition circuit other than a full-trailer such as a CDI ignition circuit.

DESCRIPTION OF SYMBOLS 1 Spark plug 2 Ignition coil 3 Primary coil 5 Main ignition circuit 6 Energy input circuit 25 Energy input switch 26 Abnormality determination means α2 Ignition power line α3 Energy input power line

Claims (5)

A main ignition circuit (5) for controlling the energization of the primary coil (3) of the ignition coil (2) to cause a spark discharge in the spark plug (1);
During the spark discharge generated by the operation of the main ignition circuit (5), electric energy is input from the negative side of the primary coil (3) toward the battery voltage supply side, thereby the main ignition circuit (5). An energy input circuit (6) for continuing the spark discharge generated by the operation;
An ignition power supply line (α2) for supplying battery voltage to the primary coil (3);
An energy input power line (α3) that is provided separately from the ignition power supply line (α2) and supplies battery voltage to the energy input circuit (6);
An energy input switch (25) for switching the intermittent state of the energy input power line (α3);
When the failure of the energy input circuit (6) is determined, the energy input switch (25) is switched to a disconnected state, and the energy input power line (α3) is disconnected without disconnecting the ignition power supply line (α2). An abnormality determining means (26) for cutting;
An internal combustion engine ignition device. The internal combustion engine ignition device according to claim 1,
The internal combustion engine ignition device switches the energy input switch (25) to a disconnected state when the engine operating state exists in the operation stop region of the energy input circuit (6). Ignition device. The internal combustion engine ignition device according to claim 1 or 2,
The internal combustion engine ignition device switches the energy input switch (25) to a disconnected state when the voltage of the battery (7) for supplying power to the internal combustion engine ignition device is lower than a predetermined voltage (V1). An ignition device for an internal combustion engine characterized by the above. A main ignition circuit (5) for controlling the energization of the primary coil (3) of the ignition coil (2) to cause a spark discharge in the spark plug (1);
During the spark discharge generated by the operation of the main ignition circuit (5), electric energy is input from the negative side of the primary coil (3) toward the battery voltage supply side, thereby the main ignition circuit (5). An energy input circuit (6) for continuing the spark discharge generated by the operation;
An ignition power supply line (α2) for supplying battery voltage to the primary coil (3);
An energy input power line (α3) that is provided separately from the ignition power supply line (α2) and supplies battery voltage to the energy input circuit (6);
A circuit cutting means (28) which is provided in the energy input power line (α3) and switches only the energy input power line (α3) to a disconnected state when a current of a predetermined current value or more flows;
An internal combustion engine ignition device. The internal combustion engine ignition device according to claim 4,
The ignition device for an internal combustion engine, wherein the circuit disconnecting means (28) is a fuse (28) that blows when a current of a predetermined current value or more flows.

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