JP2016065525A - Igniter for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress path-loss during continuing spark discharge.SOLUTION: An igniter comprises: a main ignition circuit 4 performing full transistor ignition; and an energy input circuit 5 continuing spark discharge. This energy input circuit 5 comprises a negative power supply section 10 that outputs a negative voltage lower than an earth potential of an in-vehicle battery 7. When an energy input switch Snet is turned on, a current flowing to the negative power supply section 10 by way of a primary coil 2a flows to an earth ground GND, so that it is possible to eliminate path-loss of the in-vehicle battery 7. When the energy input switch Snet is turned off, the current passing through the primary coil 2a bypasses the in-vehicle battery 7, so that it is possible to eliminate path-loss of the in-vehicle battery 7. Because it is possible to eliminate path-loss during continuing spark discharge as stated above, power consumption of the igniter can be suppressed.SELECTED DRAWING: Figure 1

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. In addition, the code | symbol used for FIG. 5 attaches | subjects the same code | symbol to the same functional thing as the "Example" mentioned later.

The new ignition device shown in FIG.
A full tiger type ignition circuit (referred to as main ignition circuit 4),
A new energy input circuit 5 for starting the continuation of the spark discharge during the spark discharge (referred to as main ignition) by the main ignition circuit 4;
It is configured by combining.

The main ignition circuit 4 is a well-known circuit, and a primary current i1 flows from the positive side to the negative side of the primary coil 2a, and a high voltage is generated in the secondary coil 2b by cutting the primary current i1. As a result, a spark discharge is generated in the spark plug 1.
Specifically, the positive side of the primary coil 2a is connected to the positive side of the in-vehicle battery 7 via the positive voltage line α. On the other hand, an ignition switch IGBT of the main ignition circuit 4 is provided between the negative side of the primary coil 2a and the ground ground GND.
When the ignition switch IGBT is turned on, the primary current i1 flows from the positive side to the negative side of the primary coil 2a, and when the ignition switch IGBT is turned off, a spark discharge is generated in the spark plug 1. Let

  The energy input circuit 5 inputs electric energy from the negative side of the primary coil 2a toward the positive voltage line α during spark discharge of the spark plug 1 by the operation of the main ignition circuit 4 (that is, during main ignition). By applying electric energy from the negative side of the primary coil 2a toward the positive voltage line α, the “secondary current i2 in the same direction as during main ignition” is continuously supplied to the secondary coil 2b. The spark discharge generated by the main ignition is continued for an arbitrary period (hereinafter, discharge duration).

Specifically, the energy input circuit 5 is
A DC positive power supply unit 100 (in the figure, + DC / DC) that boosts the battery voltage and stores positive potential electric energy;
An energy input switch Snet for controlling the electric energy input to the negative side of the primary coil 2a;
It is configured with.

Here, the ignition switch IGBT and the energy input switch Snet are ON / OFF controlled by a control circuit 6 provided in the ignition device.
The control circuit 6 performs ON / OFF control of the ignition switch IGBT and the energy input switch Snet based on the ignition signal IGt and the discharge continuation signal IGw given from the ECU 3 (abbreviation of engine control unit).

An example of the operation of the control circuit 6 will be described with reference to FIG.
When the ignition signal IGt is output (high signal), the ignition switch IGBT is turned on, the primary coil 2a is energized, and the primary current i1 flows through the primary coil 2a.
When the ignition signal IGt is stopped (low signal), the ignition switch IGBT is turned off. Then, a high voltage is generated in the secondary coil 2b by cutting off the energization of the primary coil 2a, and spark discharge (main ignition) is started in the spark plug 1.

The ECU 3 outputs the discharge duration signal IGw (high signal) during the spark discharge of the spark plug 1 and until the secondary current i2 of the secondary coil 2b decreases to the lower limit current value for maintaining the spark discharge. . Then, the positive potential electric energy boosted and stored in the positive power supply unit 100 is supplied from the minus side of the primary coil 2a to the plus side. Specifically, while the discharge duration signal IGw is being output, the control circuit 6 controls the energy input switch Snet to turn on and off the energy, thereby controlling the secondary current i2 and spark discharge. Continue.
When the discharge duration signal IGw is stopped (low signal), the operation of the energy input circuit 5 is stopped and the continuation of the spark discharge is stopped.

With this technique, it is possible to reduce the burden on the spark plug 1, suppress unnecessary power consumption, and continue the spark discharge.
Hereinafter, the spark discharge continued by the energy input circuit 5 (that is, the spark discharge following the main ignition) is referred to as “continuous spark discharge”.

(problem)
During operation of the energy input circuit 5 (during output of the discharge duration signal IGw, ON / OFF control of the energy input switch Snet, that is, “when spark discharge continues”),
(I) “Energy input” by the energy input path A for turning on the energy input switch Snet and applying positive potential electric energy from the positive power supply unit 100 from the negative side to the positive side of the primary coil 2a;
(Ii) turning off the energy input switch Snet and “at the time of energy return” by the return path B for returning the current from the negative side to the positive side of the primary coil 2a;
Are repeated alternately.

As shown in FIG. 2 (a1), the energy input path A is “positive power supply unit 100 → energy input switch Snet → energy backflow prevention diode D1 → primary coil 2a → positive side of in-vehicle battery 7 → earth ground GND → (positive power supply unit 100 again).
On the other hand, as shown in FIG. 2 (a2), the return path B is “primary coil 2a → plus side of in-vehicle battery 7 → earth ground GND → ignition switch IGBT bypass diode Dbyp → (again primary coil 2a). It is.

As described above, the in-vehicle battery 7 and the diodes existing in the energy input path A and the return path B have a path loss (electric load causing the path loss) when the spark discharge is continued (when the energy is input and when the energy is returned). Works.
As a result, there is a problem that the energy required for continuing the spark discharge increases.

A specific example is disclosed.
(I) As shown in FIG. 2 (a1), the path loss of the energy input path A is as follows: the energy input switch Snet is 0.1V, the energy backflow prevention diode D1 is 0.7V, and the in-vehicle battery 7 is 12V. Become. For this reason, a loss of 12.8 V occurs in the energy input path A.
(Ii) On the other hand, as shown in FIG. 2 (a2), the path loss of the return path B is 12V for the in-vehicle battery 7 and 0.7V for the bypass diode Dbyp. For this reason, a loss of 12.7 V occurs in the reflux path B.
As a result, as shown in FIG. 2 (a3), the total path loss during the operation of the energy input circuit 5 becomes 25.5V.
Therefore, reduction of energy required for continuing spark discharge is required.

JP 2012-001238 A

  The present invention has been made in view of the above problems, and an object thereof is to provide an ignition device for an internal combustion engine that can suppress energy required for continuing spark discharge.

The ignition device for an internal combustion engine according to the present invention connects the negative side of the negative power supply unit to the positive side of the primary coil from the negative side of the primary coil when the spark discharge generated in the spark plug is continued. Electric energy is applied toward
At this time (when energy is input), since the current that has flowed through the primary coil to the negative power supply portion flows to the ground ground GND, at least the path loss of the in-vehicle battery can be eliminated when the energy is input. Thereby, it becomes possible to suppress the required energy at the time of energy input, and it is possible to suppress power consumption at the time of energy input.

(A) Schematic block diagram of internal combustion engine ignition device, (b) Time chart for explaining operation (Example 1). It is a comparative table of a reference example (it is not a well-known technique), Example 1, and Example 2. FIG. It is a graph which shows the input energy required in order to obtain fixed output energy to a spark plug. (A) Schematic block diagram of internal combustion engine ignition device, (b) Time chart for explaining operation (Example 2). (A) Schematic block diagram of internal combustion engine ignition device, (b) Time chart for explaining operation (reference example: not a known technique).

  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]
Embodiment 1 will be described with reference to FIGS.
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.
When a specific example of the engine is disclosed (of course, it is not limited), the engine of this embodiment is a direct-injection engine capable of lean burn (lean burn combustion) using gasoline as fuel, and exhaust gas. An EGR device for returning a part of the gas to the engine intake side as EGR gas is mounted, and further provided is a swirl flow control means for generating a swirl flow (tumble flow, swirl flow, etc.) of the air-fuel mixture in the cylinder.
That is, the engine of this embodiment has an operation region where the ignitability of the air-fuel mixture is lowered.

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

  The ECU 3 generates an ignition signal IGt and a discharge continuation signal in accordance with engine parameters (warm-up state, engine speed, engine load, etc.) acquired from various sensors and engine control states (existence of lean combustion, degree of swirl flow, etc.). Generate and output IGw.

The ignition device mounted on the vehicle
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 full tiger operation;
An energy input circuit 5 that performs continuous spark discharge;
A control circuit 6 that performs operation control;
It is configured with.

  The main parts of the main ignition circuit 4 and the energy input circuit 5 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 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, and is applied from the secondary coil 2b. 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 2a and a secondary coil 2b having a larger number of turns than the number of turns of the primary coil 2a.
One end (plus side) of the primary coil 2 a is connected to a plus voltage line α that receives power from the plus side of the in-vehicle battery 7.
The other end side (minus side) of the primary coil 2 a is grounded via an ignition switch IGBT (for example, IGBT, power transistor, MOS FET, thyristor, etc.) of 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, when receiving the output (high signal) of the ignition signal IGt, the control circuit 6 turns on the ignition switch IGBT. Thereby, the primary current i1 flows from the positive side to the negative side of the primary coil 2a.
Further, when the ignition signal IGt stops (low signal), the control circuit 6 turns off the ignition switch IGBT. As a result, the primary current i1 is cut, a high voltage is generated in the secondary coil 2b, and a spark discharge (main ignition) is generated in the spark plug 1.

  The energy input circuit 5 inputs electric energy from the negative side of the primary coil 2a toward the positive side during the main ignition generated in the spark plug 1 by the operation of the main ignition circuit 4, thereby providing the secondary coil 2b with “ The secondary current i2 "in the same direction as that at the time of main ignition is continuously supplied, and the spark discharge generated by the operation of the main ignition circuit 4 is continued for an arbitrary period (discharge duration).

  Specifically, the energy input circuit 5 operates in an engine operating region where the ignitability decreases (during lean combustion, generation of strong swirling flow, high EGR rate, low temperature start, etc.), and continues spark discharge. In order to improve the ignitability of the air-fuel mixture, the negative power source 10 (−DC / DC in the figure) is connected to the positive side of the primary coil 2a during the spark discharge of the spark plug 1 by the operation of the main ignition circuit 4. By connecting the negative side, electric energy is input from the negative side to the positive side of the primary coil 2a.

The negative power source unit 10 is a DC power source that outputs a negative voltage lower than the ground potential of the in-vehicle battery 7.
The specific configuration of the negative power supply unit 10 is not limited, and is a negative conversion type DC / DC converter that converts a positive DC output output from the in-vehicle battery 7 to generate a negative DC output.
For the purpose of assisting understanding, an example of the negative power supply unit 10 will be described. The negative power supply unit 10 disclosed as an example is a DC / AC / DC converter that AC converts positive DC output to obtain negative DC output, and is configured using an inverter, an insulating transformer, a rectifier circuit, and a capacitor.

In the operation of the DC / AC / DC converter, first, the DC output of the in-vehicle battery 7 is converted into AC using an inverter. The AC output is applied to the primary coil of the insulating transformer, the AC output insulated from the secondary coil is taken out, and the AC output is DC converted by a rectifier circuit (diode bridge or the like). Furthermore, the voltage is smoothed by the capacitor and the charge is stored by the capacitor. Then, by adopting a circuit configuration in which the positive side of the capacitor is grounded to the vehicle, the negative side of the in-vehicle battery 7 (the ground potential of the vehicle) and the positive side of the capacitor are made equal. As a result, a negative DC output can be generated on the negative side of the capacitor. The negative voltage value to be generated can be arbitrarily set by the winding ratio of the insulating transformer or the like.
Of course, the above-described DC / AC / DC converter is an example of the negative power supply unit 10 and is not limited. Other circuit configurations such as a charge pump type using a multivibrator are employed to output a negative voltage. Also good.

  The negative voltage value generated by the negative power supply unit 10 is set based on the voltage value required to maintain the spark discharge, the winding ratio of the ignition coil 2, and the like, and an example is disclosed. The negative power supply unit 10 of this embodiment is provided to output −150 V to −200 V on the minus side.

When the energy input circuit 5 continues the spark discharge of the spark plug 1,
(I) At the time of energy input for connecting the negative side of the negative power supply unit 10 to the positive side of the primary coil 2a,
(Ii) Stop the connection of the negative side of the negative power supply unit 10 to the positive side of the primary coil 2a (that is, stop the input of energy by the negative power source unit 10) from the negative side of the primary coil 2a At the time of energy recirculation that recirculates the current toward the positive side,
Are provided to repeat alternately.

The ignition device is a means for switching between energy input and energy return,
A positive voltage line α connecting the positive side of the primary coil 2a to the positive side of the in-vehicle battery 7,
A reflux switch Sref (for example, a MOS type FET, a power transistor, etc.) for intermittently connecting the positive voltage line α,
A negative voltage line β connecting the positive side of the primary coil 2a to the negative side of the negative power supply unit 10,
An energy input switch Snet (for example, a MOS-type FET, a power transistor, etc.) for intermittently connecting the negative voltage line β;
Is provided.

The energy input switch Snet, the reflux switch Sref, and a bypass switch Sbyp, which will be described later, are ON / OFF controlled by the control circuit 6,
The energy input switch Snet is turned on when energy is input to the primary coil 2a.
The reflux switch Sref is turned off only when the energy input switch Snet is turned on.
The bypass switch Sbyp is turned on only during the operation period of the energy input circuit 5 (period in which the discharge continuation signal IGw is received from the ECU 3).

Specifically, the energy input circuit 5 is
(I) At the time of energy input, the energy input switch Snet is turned ON and the reflux switch Sref is turned OFF to form the energy input path A, and the negative side of the negative power supply unit 10 is connected to the positive side of the primary coil 2a. By connecting, current flows from the minus side of the primary coil 2a toward the plus side,
(Ii) At the time of energy recirculation, the energy input switch Snet is turned off and the recirculation switch Sref is turned on to form a recirculation path B via the bypass switch Sbyp, and from the minus side to the plus side of the primary coil 2a The current that flows is returned.

The control circuit 6 that alternately switches between energy input and energy return is equipped with a secondary current controller that controls the secondary current i2 by alternately turning on and off the energy input switch Snet and the return switch Sref. ing.
An example of a specific secondary current controller is to monitor the secondary current i2 flowing through the secondary coil 2b using the current detection resistor 9, and input energy so that the monitored secondary current i2 maintains a predetermined target range. Feedback control for alternately turning on and off the switch Snet and the reflux switch Sref is employed.

Note that the secondary current controller is not limited to the feedback control described above, and performs ON-OFF control of the energy input switch Snet by open loop control so that the secondary current i2 maintains a predetermined target range. There may be.
Further, the target value of the secondary current i2 when performing feedback control or open loop control may be constant or changed in accordance with the engine operating state (for example, an instruction signal given from the ECU 3). It may be a thing.

The ignition device of this embodiment is
A bypass line γ connecting the plus side of the in-vehicle battery 7 (that is, the plus voltage line α) and the minus side of the primary coil 2a (specifically, between the primary coil 2a and the ignition switch IGBT);
A bypass diode Dbyp that allows current to flow only from the plus side of the in-vehicle battery 7 to the minus side of the primary coil 2a in the bypass line γ,
A bypass switch Sbyp (for example, a MOS type FET, a power transistor, etc.) for intermittently connecting the bypass line γ,
It is configured with.

  This bypass switch Sbyp is turned on by the control circuit 6 when spark discharge is continued (when energy is input and when energy is recirculated) that receives the discharge continuation signal IGw from the ECU 3, and the bypass switch Sbyp is turned on when spark discharge is continued. By being turned on, a current can flow only from the plus side of the in-vehicle battery 7 toward the minus side of the primary coil 2a.

Specifically, in a state where the bypass switch Sbyp is turned on when the spark discharge is continued,
(I) When the energy input switch Snet is turned on and the reflux switch Sref is turned off, as shown in FIG. 2 (b1), “grounding ground → the negative side of the vehicle battery 7 → the bypass switch Sbyp → the bypass diode An energy input path A through which current flows is formed in the order of Dbyp → primary coil 2a → energy input switch Snet → negative power supply unit 10 → (ground earth GND) again,
(Ii) When the energy input switch Snet is turned off and the return switch Sref is turned on, as shown in FIG. 2 (b2), “primary coil 2a → reflux switch Sref → bypass switch Sbyp → bypass diode Dbyp → A reflux path B through which a current flows in the order of (again, primary coil 2a) is formed.

(Explanation of ignition device operation)
When the ignition signal IGt is output (high signal),
(A) While the ignition switch IGBT is turned ON over the output period of the ignition signal IGt,
(B) The negative power supply unit 10 operates over the output period of the ignition signal IGt, and the negative potential electric energy is stored in power storage means (a capacitor or the like) mounted on the negative power supply unit 10.

(C) When the ignition signal IGt is stopped (low signal), 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.

(D) After the main ignition is started by the spark plug 1, the secondary current i2 is attenuated in a substantially triangular wave shape. And before secondary current i2 falls to a predetermined lower limit current value (current value for maintaining spark discharge), ECU 3 outputs discharge continuation signal IGw (high signal).

(E) When the discharge continuation signal IGw is output (high signal), the energy input circuit 5 is operated by the control circuit 6.
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 (high signal), the secondary current controller provided in the control circuit 6 alternately turns on and off the energy input switch Snet and the return switch Sref to input energy. The energy input through which the current flows through the path A and the energy reflux through which the current flows through the return path B are alternately repeated. Thereby, the primary current i1 of the primary coil 2a is controlled, the secondary current i2 of the secondary coil 2b is controlled, and the spark discharge in the spark plug 1 is continued.

  Specifically, the current flows from the minus side to the plus side of the primary coil 2a each time the energy input switch Snet is turned on. 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. As described above, the secondary current controller controls the energy input switch Snet on and off, so that the secondary current i2 is controlled in a range where spark discharge can be maintained.

This will be described more specifically. 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 i2 is decreased. 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 electric 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, the discharge sustaining voltage can be maintained, and blowing out of the spark discharge can be avoided.
On the contrary, if the secondary current i2 increases during continuous spark discharge, the energy input switch Snet is turned off by feedback control of the secondary current i2, and the amount of electric energy input to the primary coil 2a is reduced. As a result, the secondary current i2 is kept within a substantially constant range.

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

(F) When the ignition continuation signal IGw is stopped (low signal), the operation of the energy input circuit 5 is stopped and the continuous spark discharge is terminated.
Specifically, when the operation of the energy input circuit 5 stops, the control circuit 6 turns on the reflux switch Sref, and returns to the initial state where the battery voltage is supplied to the plus side of the primary coil 2a.

(Effect 1 of Example 1)
As described above, the ignition device according to the first embodiment connects the negative side of the negative power supply unit 10 to the positive side of the primary coil 2a when the spark discharge generated in the spark plug 1 is continued. Electric energy is input from the minus side of 2a toward the plus side.
When the energy input switch Snet is turned on, the current flowing through the primary coil 2a to the negative power supply unit 10 flows to the ground ground GND. Therefore, the path loss of the in-vehicle battery 7 may be eliminated when the energy is input. it can.
Further, during the energy circulation in which the energy input switch Snet is turned off, the current passing through the primary coil 2a bypasses the in-vehicle battery 7, so that the path loss of the in-vehicle battery 7 can be eliminated during the energy circulation.
As described above, it is possible to suppress the required energy when the spark discharge is continued (when the energy is input and when the energy is returned), and it is possible to suppress the electric power used when the spark discharge is continued. That is, the power consumption of the ignition device can be suppressed by employing the present invention.

The above “Effect 1” will be specifically described.
(I) As shown in FIG. 2 (b1), the energy input path A is “earth ground GND → minus side of vehicle battery 7 → bypass switch Sbyp → bypass diode Dbyp → primary coil 2a → energy input switch Snet → negative. “Power supply unit 10 → (Earth grounding GND again)”.
(Ii) The energy circulation path B is “primary coil 2a → reflux switch Sref → bypass switch Sbyp → bypass diode Dbyp → (again, primary coil 2a)” as shown in FIG. 2 (b2).

As shown in FIG. 2 (b1), the path loss of the energy input path A is -12V for the in-vehicle battery 7, 0.1V for the bypass switch Sbyp, 0.7V for the bypass diode Dbyp, and 0.2 for the energy input switch Snet. 1V. For this reason, the total loss (subtotal) of the energy input path A is −11.1V.
On the other hand, as shown in FIG. 2 (b2), the return loss of the return path B is 0.1V for the return switch Sref, 0.1V for the bypass switch Sbyp, and 0.7V for the bypass diode Dbyp. For this reason, the total loss (subtotal) of the reflux path B becomes 0.9V.

As a result, as shown in FIG. 2 (b3), the total path loss during the operation of the energy input circuit 5 in the first embodiment becomes −10.2V.
As a result, in comparison with the “new ignition device (see FIG. 5)” disclosed as the reference technology, in Example 1, the path loss when the spark discharge is continued (when the energy is input and when the energy is returned) is reduced. As shown in FIG. 2 (b4), 35.7V can be reduced as the difference.

The energy reduction effect at the time of energy input is demonstrated with reference to FIG.
In the case of the “new ignition device (see FIG. 5)” disclosed as the reference technology, the required energy of the energy input circuit 5 is Y1 when the spark plug 1 generates the predetermined output energy X1.
On the other hand, in the case of the “ignition device of the first embodiment (see FIG. 1)”, when the spark plug 1 generates the predetermined output energy X2 (= X1), the required energy of the energy input circuit 5 is Y2 (< Y1).
Thus, by adopting the first embodiment, it is possible to suppress the power consumption of the ignition device that continues the spark discharge.

(Effect 2 of Example 1)
As described above, the ignition device of Example 1 is
(I) At the time of energy input, a current that flows to the negative power supply unit 10 through the primary coil 2a flows to the ground ground GND,
(Ii) During energy circulation, the current passing through the primary coil 2a flows bypassing the on-vehicle battery 7.
That is, in the ignition device of the first embodiment, when the energy input circuit 5 is operated, the voltage increase due to the energy input does not occur on the plus side of the in-vehicle battery 7.

For this reason, there is no concern that other electrical devices (vehicle devices different from the ignition device) that receive the battery voltage from the vehicle battery 7 are affected by the operation of the energy input circuit 5.
Further, when the energy is turned on, since the power obtained by adding the negative voltage of the negative power supply unit 10 and the positive voltage of the in-vehicle battery 7 is input to the primary coil 2a, the burden on the negative power supply unit 10 can be reduced, and the negative power supply unit 10 can be miniaturized.

[Example 2]
A second embodiment will be described with reference to FIGS. 4, 2, and 3.
In the ignition device of the first embodiment, an example is shown in which current is supplied from the plus side of the in-vehicle battery 7 to the minus side of the primary coil 2a using the bypass line γ when energy is input and when energy is recirculated.
On the other hand, the ignition device of the second embodiment eliminates the bypass line γ of the first embodiment and bypasses the current flow only from the earth ground GND toward the negative side of the primary coil 2a in parallel with the ignition switch IGBT. A diode Dbyp is provided;
(I) At the time of energy input, the vehicle-mounted battery 7 is bypassed to pass a current to the negative side of the primary coil 2a via the vehicle's ground ground GND and the bypass diode Dbyp,
(Ii) At the time of energy recirculation, a current is supplied to the negative side of the primary coil 2a via the in-vehicle battery 7, the vehicle earth ground GND, and the bypass diode Dbyp.

By providing in this way,
(I) As shown in FIG. 2 (c1), the energy input path A is “earth ground GND → bypass diode Dbyp → primary coil 2a → energy input switch Snet → negative power source 10 → (again, ground ground GND)”. It is.
(Ii) As shown in FIG. 2 (c2), the energy circulation path B is “primary coil 2a → reflux switch Sref → positive side of in-vehicle battery 7 → earth ground GND → bypass diode Dbyp → (again, primary coil 2a ) ”.

As shown in FIG. 2C1, the path loss of the energy input path A is 0.7V for the bypass diode Dbyp and 0.1V for the energy input switch Snet. For this reason, the total loss (subtotal) of the energy input path A is 0.8V.
On the other hand, as shown in FIG. 2 (c2), the return loss of the return path B is 0.1V for the return switch Sref, 12V for the in-vehicle battery 7, and 0.7V for the bypass diode Dbyp. For this reason, the loss of the reflux path B is 12.8V.

As a result, as shown in FIG. 2 (c3), the total path loss during the operation of the energy input circuit 5 in the second embodiment is 13.6V.
As a result, in comparison with the “new ignition device (see FIG. 5)” disclosed as the reference technology, in the second embodiment, the path loss when the spark discharge is continued (when the energy is input and when the energy is returned) is reduced. As shown in FIG. 2 (c4), 11.9V can be reduced as the difference.

The energy reduction effect at the time of energy input is demonstrated with reference to FIG.
As described above, in the case of the “new ignition device (see FIG. 5)” disclosed as the reference technique, when the predetermined output energy X1 is generated by the spark plug 1, the required energy of the energy input circuit 5 is Y1. .
On the other hand, in the case of this “ignition device of Embodiment 2 (see FIG. 4)”, when the spark plug 1 generates a predetermined output energy X3 (= X1), the energy required for the energy input circuit 5 is set to Y3 (< Y1).
As described above, by adopting the second embodiment, it is possible to suppress the power consumption of the ignition device that continues the spark discharge.

  In the above embodiment, an example in which a semiconductor switch (MOS FET, power transistor, etc.) is used as an example of each switch has been described. However, the present invention is not limited thereto. Switch) or the like may be used.

  In the above embodiment, an example in which the ignition device of the present invention is used for a gasoline engine has been shown. However, since the ignitability of the air-fuel mixture can be improved by continuous spark discharge, it is applied to an engine using ethanol fuel or mixed fuel. May be. 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 according to the present invention is used for a lean burn engine capable of lean burn (lean burn combustion) operation, and the ignition property at the time of lean combustion in which the ignitability is deteriorated is improved by continuous spark discharge. However, since it is possible to improve the ignitability by continuous spark discharge even in a combustion state different from lean combustion, it is not limited to application to lean burn engines, and is used for engines that do not perform lean combustion. Also good.

Further, the present invention may be applied to a high EGR engine (an engine capable of increasing the return rate of EGR gas), and continuous spark discharge may be generated at high EGR to improve 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 of the present invention is used for a direct injection engine that directly injects fuel into a combustion chamber has been shown. However, the present invention is not limited to this, and the fuel is disposed upstream of the intake valve (inside the intake port). You may use for the port injection type engine which injects.

  In the above embodiment, the ignition device of the present invention is used for an engine that actively generates a swirling flow of air-fuel mixture (such as a tumble flow or a swirl flow) in a cylinder, and a spark discharge by a swirling flow is performed by continuous spark discharge. Although an example of avoiding “erasing” is disclosed, it may be used for an engine that does not have a 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 a DI type ignition device that uses the ignition coil 2 for each spark plug 1, but the present invention is not limited to the DI type.

  In the above embodiment, the full tiger type is shown as a specific example of the main ignition circuit 4, but the main ignition circuit 4 may be a CDI type.

DESCRIPTION OF SYMBOLS 1 Spark plug 2 Ignition coil 2a Primary coil 5 Energy input circuit 7 Vehicle-mounted battery 10 Negative power supply part

Claims (6)

During the spark discharge of the spark plug (1), the spark discharge generated in the spark plug (1) by supplying electric energy from the negative side to the positive side of the primary coil (2a) in the ignition coil (2). In the internal combustion engine ignition device comprising the energy input circuit (5) for continuing
The energy input circuit (5) includes a DC negative power supply unit (10) that outputs a negative voltage lower than the ground potential of the vehicle battery (7),
By connecting the negative side of the negative power source (10) to the positive side of the primary coil (2a) during the spark discharge of the spark plug (1), from the negative side of the primary coil (2a) An ignition device for an internal combustion engine, wherein electric energy is input toward a plus side. The internal combustion engine ignition device according to claim 1,
When the energy input circuit (5) continues the spark discharge of the spark plug (1),
At the time of energy input for connecting the negative side of the negative power supply unit (10) to the positive side of the primary coil (2a),
At the time of energy recirculation that stops the energy input by the negative power supply unit (10) and recirculates the current from the negative side to the positive side of the primary coil (2a),
An ignition device for an internal combustion engine characterized by alternately repeating the above. The internal combustion engine ignition device according to claim 2,
This internal combustion engine ignition device is
A negative voltage line (β) for connecting the positive side of the primary coil (2a) to the negative side of the negative power source section (10);
A positive voltage line (α) connecting the positive side of the primary coil (2a) to the positive side of the in-vehicle battery (7);
An energy input switch (Snet) for intermittently connecting the negative voltage line (β);
A reflux switch (Sref) for intermittently connecting the positive voltage line (α);
An ignition device for an internal combustion engine comprising: The internal combustion engine ignition device according to claim 3,
The energy input circuit (5)
At the time of energy input, the energy input switch (Snet) is turned on, the reflux switch (Sref) is turned off,
An ignition apparatus for an internal combustion engine, wherein the energy input switch (Snet) is turned off and the reflux switch (Sref) is turned on at the time of the energy recirculation. The internal combustion engine ignition device according to claim 4,
The internal combustion engine ignition device includes a bypass line (γ) that connects a plus side of the on-vehicle battery (7) and a minus side of the primary coil (2a), and a bypass switch (γ) that intermittently connects the bypass line (γ). Sbyp)
When the energy is input and when the energy is returned, the bypass switch (Sbyp) is turned on, and the negative side of the primary coil (2a) from the positive side of the in-vehicle battery (7) through the bypass line (γ) An internal combustion engine ignition device characterized by flowing an electric current toward The internal combustion engine ignition device according to claim 4,
In this internal combustion engine ignition device, in parallel with an ignition switch (IGBT) for generating main ignition in the ignition plug (1), the grounding (GND) of the vehicle is directed to the negative side of the primary coil (2a). A bypass diode (Dbyp) for passing current through
When the energy is input, the vehicle-mounted battery (7) is bypassed to pass a current toward the negative side of the primary coil (2a) through the earth ground (GND) and the bypass diode (Dbyp),
When the energy is returned, an internal current is caused to flow toward the negative side of the primary coil (2a) through the on-vehicle battery (7), the ground (GND), and the bypass diode (Dbyp). Engine ignition device.

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