WO2019106776A1

WO2019106776A1 - Spark device

Info

Publication number: WO2019106776A1
Application number: PCT/JP2017/042956
Authority: WO
Inventors: 中川　光; 亮祐小林; 村上　哲; 裕一村本; 棚谷　公彦
Original assignee: 三菱電機株式会社
Priority date: 2017-11-30
Filing date: 2017-11-30
Publication date: 2019-06-06
Also published as: JPWO2019106776A1; JP6811877B2

Abstract

In the present invention, control is performed such that a power conversion operation by a DC/DC conversion device 5 is stopped in at least one of: a period from a time when a high-voltage power supply 2 generates voltage for a spark plug 1 to a time when capacitive discharge current due to dielectric breakdown between electrodes of the spark plug 1 is attenuated to a predetermined value; and a period during which a DC/AC conversion device 4 outputs AC power to the spark plug 1.

Description

Igniter

The present invention relates to an igniter that mainly uses plasma discharge by AC power.

As a method to improve the fuel efficiency of an internal combustion engine mounted on a vehicle or the like, a lean combustion method of burning lean fuel, an exhaust gas recirculation method of recirculating exhaust gas after fuel combustion into the combustion chamber, or a high compression ratio of the combustion chamber And other methods are in progress. However, in either method, there is a problem that it is difficult to ignite the fuel, and improvement of the ignitability is required.

Conventionally, as one method for enhancing the ignitability to fuel in an ignition device of an internal combustion engine, for example, there is a high frequency plasma ignition device disclosed in Patent Document 1. A general ignition device for an internal combustion engine generates a high voltage by a high voltage power source for insulation breakdown composed of an ignition coil and an igniter to generate a spark discharge between electrodes of a spark plug. The high frequency plasma igniter includes a high frequency alternating current power supply in addition to the high voltage power supply for dielectric breakdown, and immediately after the start of the discharge by the high voltage power supply for dielectric breakdown, between the electrodes of the spark plug in megahertz (hereinafter referred to as MHz) order By supplying a high frequency voltage and continuously generating a high temperature and high pressure high frequency plasma between the electrodes of the spark plug, the ignitability of the gasified fuel is enhanced.

The ignition device disclosed in Patent Document 1 includes a high voltage power supply for insulation breakdown and a high frequency AC power supply, and the high frequency AC power supply includes a battery, a full bridge inverter circuit, a high frequency transformer, and an LC resonant circuit. Composed of Patent Document 1 describes that a DC / DC conversion device may be connected between a full bridge inverter of a high frequency AC power supply and a battery.

As well known, when the battery voltage is boosted by the DC / DC conversion device to charge the output capacitor, the charging voltage of the output capacitor (also referred to as applied voltage or output voltage may be referred to as “charging in the following description. Voltage is detected, and charging is stopped when the charging voltage of the output capacitor reaches a predetermined threshold, and charging is resumed when the charging voltage of the output capacitor falls below the threshold. Technology exists. The charging voltage of the output capacitor gradually decreases due to power consumption on the load side and natural discharge with the passage of time. As a result, the DC / DC conversion device repeats the voltage conversion operation and the stop to keep the charging voltage of the output capacitor at a predetermined value.

Here, in the conventional ignition device configured as in Patent Document 1, when the high voltage power source applies a high voltage to the spark plug and causes a dielectric breakdown between the electrodes of the spark plug, the spark plug is instantaneous A large capacity discharge current flows. Since this capacitive discharge current is the one in which the charge stored in the capacitor of the LC resonant circuit connected to the spark plug and the parasitic capacitance in the vicinity of the spark plug is released, it is used in the path of the spark plug, high frequency transformer, and LC resonant circuit. It also flows. Therefore, the capacitive discharge current also flows into the full bridge inverter and the DC / DC converter via the high frequency transformer, and is consumed by circulating the semiconductor switches and the like that constitute the inverter.

Further, in the conventional ignition device configured as in Patent Document 1, when AC power is output from the full bridge inverter to the spark plug, a common ground in which a part of the output AC current is connected to the internal combustion engine It flows into the common GND which is a potential part. The current flowing into the common GND flows into the reference potential of the high frequency AC power supply through the common GND, and is returned through the parasitic capacitance or the like.

JP, 2015-86702, A

In the above-described conventional igniter, since the capacitive discharge current and the alternating current have a high frequency of MHz order or more, when flowing into the reference potential of the DC / DC conversion device, voltage oscillation is caused by parasitic inductance such as wiring. In particular, if the capacitive discharge current and the alternating current flow simultaneously to the reference potential of the DC / DC conversion device, voltage oscillation of the reference potential at the reference potential of the DC / DC conversion device results by superimposing these two currents. It gets very big. Since the voltage oscillation of the reference potential of the DC / DC conversion device is superimposed on the control signal and the sensor detection value, it is also superimposed on the voltage detection device that detects the charging voltage of the output capacitor of the DC / DC conversion device, Large errors may occur in the detection value of the voltage detection device.

Due to the influence of the error of the detection value of the voltage detection device described above, when the charging voltage of the output capacitor is detected lower than the actual value, the DC / DC conversion device will output more power than necessary to the output capacitor. As a result, the charging voltage of the output capacitor becomes larger than the originally intended value, so that the switching loss and the like of the semiconductor of the DC / DC converter in the ignition device increase, causing an increase in power loss.

The present invention has been made to solve the above-mentioned problems in the conventional ignition device, and the DC / DC conversion device outputs a large power more than necessary due to the error of the voltage detection value of the voltage detection means. It is an object of the present invention to provide an igniter capable of preventing the increase in power loss.

The igniter according to the invention is
An ignition plug including a first electrode and a second electrode facing each other through a gap, for igniting fuel in a combustion chamber of an internal combustion engine;
A high voltage power supply that applies a voltage to the spark plug to cause dielectric breakdown in the gap;
A high frequency alternating current power supply for applying a high frequency voltage to the spark plug to generate high frequency plasma in the gap;
A DC power supply for supplying power to the high voltage power supply and the high frequency AC power supply;
A control device that controls the operation of the high voltage power supply and the high frequency alternating current power supply;
An igniter having
The high frequency alternating current power supply is
A DC / AC conversion device which converts DC power into AC power of a predetermined frequency and outputs the converted AC power to the spark plug;
A DC / DC conversion device that converts DC power from a DC power supply into DC power having a predetermined voltage value and outputs the converted DC power to the DC / AC conversion device;
Equipped with
The controller is
In a period satisfying at least one of a period in which the capacity discharge current generated by the dielectric breakdown is smaller than a predetermined value, and a period in which the DC / AC conversion device does not output the AC power to the spark plug. The DC / DC conversion device is configured to perform a power conversion operation,
It is characterized by

Also, the ignition device according to the present invention is
An ignition plug including a first electrode and a second electrode facing each other through a gap, for igniting fuel in a combustion chamber of an internal combustion engine;
A high voltage power supply that applies a voltage to the spark plug to cause dielectric breakdown in the gap;
A high frequency alternating current power supply for applying a high frequency voltage to the spark plug to generate high frequency plasma in the gap;
A DC power supply for supplying power to the high voltage power supply and the high frequency AC power supply;
A control device that controls the operation of the high voltage power supply and the high frequency alternating current power supply;
An igniter having
The high frequency alternating current power supply is
A DC / AC conversion device which converts DC power into AC power having a predetermined frequency and outputs the converted AC power to the spark plug;
A DC / DC conversion device that converts DC power from a DC power supply into DC power having a predetermined voltage value and outputs the converted DC power to the DC / AC conversion device;
Equipped with
The DC / DC conversion device
A power supply capacitor for charging energy of the converted DC power;
Voltage detection means for detecting the charging voltage of the power supply capacitor;
Equipped with
The controller is
After the high voltage power supply applies a voltage to the spark plug, the high voltage power supply supplies a voltage to the spark plug in a period until the capacitive discharge current generated by the dielectric breakdown becomes smaller than a predetermined value. It is configured to control a power conversion operation of the DC / DC conversion device using a detection value of the voltage detection means immediately before applying.
It is characterized by

Furthermore, the ignition device according to the present invention
An ignition plug including a first electrode and a second electrode facing each other through a gap, for igniting fuel in a combustion chamber of an internal combustion engine;
A high voltage power supply that applies a voltage to the spark plug to cause dielectric breakdown in the gap;
A high frequency alternating current power supply for applying a high frequency voltage to the spark plug to generate high frequency plasma in the gap;
A DC power supply for supplying power to the high voltage power supply and the high frequency AC power supply;
A control device that controls the operation of the high voltage power supply and the high frequency alternating current power supply;
An igniter having
The high frequency alternating current power supply is
A DC / AC conversion device which converts DC power into AC power having a predetermined frequency and outputs the converted AC power to the spark plug;
A DC / DC conversion device that converts DC power from a DC power supply into DC power having a predetermined voltage value and outputs the converted DC power to the DC / AC conversion device;
Equipped with
The DC / DC conversion device
A power supply capacitor for charging energy of the converted DC power;
Voltage detection means for detecting the charging voltage of the power supply capacitor;
Equipped with
The controller is
In a period in which the DC / AC converter outputs a current to the spark plug, the DC / DC conversion is performed using a detection value of the voltage detection unit immediately before the DC / AC converter outputs a current to the spark plug. Configured to control the power conversion operation of the device,
It is characterized by

According to the ignition device of the present invention, the high frequency AC power supply converts DC power into AC power of a predetermined frequency, and outputs the converted AC power to the spark plug from the DC / AC conversion device, and DC power supply And DC / DC conversion device for converting the DC power of the device into DC power having a predetermined voltage value and outputting the converted DC power to the DC / AC conversion device, the control device generating The DC / DC in a period in which at least one of a period in which the capacity discharge current is smaller than a predetermined value and a period in which the DC / AC conversion device does not output the AC power to the spark plug Since the converter is configured to perform control so as to perform the power conversion operation, it is possible that the dielectric breakdown is generated while the DC / DC conversion device performs the power conversion operation. An output AC current of the amount the discharge current and the DC / AC conversion device, prevents flow into the reference potential of the DC / DC converter at the same time, it is possible to suppress the detection error of the voltage detecting means. As a result, it is possible to prevent the DC / DC conversion device from outputting an unnecessarily large power due to the influence of the detection error, and to prevent an increase in power loss.

Further, according to the present invention, the DC / DC conversion device includes a power supply capacitor for charging the energy of the converted direct current power, and a voltage detection unit for detecting a charging voltage of the power supply capacitor. The control device is configured such that, after the high voltage power supply applies a voltage to the spark plug, the high voltage power supply is operated in a period until the capacitive discharge current generated by the dielectric breakdown becomes smaller than a predetermined value. Since the power conversion operation of the DC / DC conversion device is controlled using the detection value of the voltage detection means immediately before applying the voltage to the spark plug, the influence of the detection error caused by the voltage oscillation Thus, it is possible to prevent the DC / DC conversion device from outputting an unnecessarily large power and to prevent an increase in power loss.

Further, according to the present invention, the DC / DC conversion device comprises: a power supply capacitor for charging the energy of the converted DC power; and voltage detection means for detecting a charging voltage of the power supply capacitor. The control device uses a detection value of the voltage detection means immediately before the DC / AC conversion device outputs a current to a spark plug in a period during which the DC / AC conversion device outputs a current to the spark plug. , Since the power conversion operation of the DC / DC conversion device is controlled, the DC / DC conversion device is prevented from outputting an unnecessarily large power due to the influence of the detection error caused by the voltage oscillation. Can prevent an increase in power loss.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which comprises schematic structure of the ignition device which concerns on Embodiment 1 of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram of the ignition device which concerns on Embodiment 1 of this invention. It is a timing chart which shows the general operation sequence of the ignition device concerning Embodiment 1 of this invention. It is a flowchart which shows the operation | movement sequence of the ignition device which concerns on Embodiment 1 of this invention. It is a flowchart which shows the operation | movement sequence of the ignition device which concerns on Embodiment 1 of this invention, and shows the flowchart of the detailed operation sequence of step S05 in FIG. It is a flowchart which shows the operation | movement sequence of the ignition device which concerns on Embodiment 1 of this invention, and shows the flowchart of another detailed operation sequence of step S05 in FIG. It is an explanatory view explaining operation of an ignition device concerning Embodiment 1 of this invention. It is a flowchart which shows the operation | movement sequence of the DC / DC conversion apparatus in the ignition device which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the conditions when DC / DC conversion apparatus performs electric power conversion operation. It is explanatory drawing which shows the relationship between the conditions when the DC / DC conversion apparatus performs electric power conversion operation, and the detection error of a voltage detection means. It is a timing chart which shows the general operation sequence of the ignition device concerning Embodiment 2 of this invention. It is a flowchart which shows the operation | movement sequence of the ignition device which concerns on Embodiment 2 of this invention. It is another timing chart which shows the general | schematic operation | movement sequence of the ignition device which concerns on Embodiment 2 of this invention. It is a flowchart which shows the operation | movement sequence of the ignition device which concerns on Embodiment 3 of this invention. It is another timing chart which shows the general | schematic operation | movement sequence of the ignition device which concerns on Embodiment 3 of this invention.

Hereinafter, the ignition device of the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.
Embodiment 1
First, an ignition device according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of an ignition device according to Embodiment 1 of the present invention. In FIG. 1, an ignition device 10 includes an ignition plug 1, a high voltage power supply 2, a high frequency AC power supply 3 having a DC / AC conversion device and a DC / DC conversion device 5, a DC power supply 6, and a control device 7. Is equipped. The spark plug 1 is mounted on an internal combustion engine (not shown) and includes a first electrode 1a and a second electrode 1b exposed in a combustion chamber of the internal combustion engine. The first electrode 1a and the second electrode 1b are opposed to each other via a predetermined gap. The igniter 10 generates high frequency plasma in the gap between the first electrode 1 a and the second electrode 1 b of the spark plug 1 according to the ignition command signal output from the control unit 7 every ignition cycle Ti. , Ignites the fuel inside the combustion chamber of the internal combustion engine.

The high voltage power supply 2 generates a high voltage for causing a dielectric breakdown in the gap between the first electrode 1 a and the second electrode 1 b of the spark plug 1. The DC / AC conversion device 4 performs a power conversion operation of converting energy as DC power supplied from the DC / DC conversion device 5 into energy as AC power. The AC power output from the DC / AC converter 4 is supplied to the spark plug 1 to generate a high frequency discharge in the gap between the first electrode 1a and the second electrode 1b. The DC / DC conversion device 5 can convert DC power from the DC power supply 6 into DC power having an arbitrary DC voltage value, and more specifically, a predetermined DC voltage value optimum for the device. Power conversion operation to convert into DC power and output to the DC / AC converter 4.

The direct current power supply 6 includes a battery or the like mounted on a vehicle, and supplies power to the high voltage power supply 2 and the high frequency alternating current power supply 3. The control device 7 includes an engine control unit or a microcomputer and controls the operations of the high voltage power supply 2 and the high frequency AC power supply 3. The DC / AC conversion device 4 and the DC / DC conversion device 5 have semiconductor switches as switching elements as described later in the circuit configuration.

Next, a more specific circuit configuration and an operation sequence of the ignition device according to Embodiment 1 of the present invention will be described. FIG. 2 is a block diagram of the ignition device according to the first embodiment of the present invention, and shows a specific circuit configuration of the ignition device shown in FIG. In FIG. 2, the igniter 10 has a spark plug 1 having a first electrode 1 a and a second electrode 1 b and a gap between the first electrode 1 a and the second electrode 1 b of the spark plug 1. A high voltage power supply 2 that applies a voltage to cause dielectric breakdown in the gap, and outputs alternating current power having a predetermined frequency to the spark plug 1 to generate a voltage between the first electrode 1a and the second electrode 1b. A high frequency AC power supply 3 for generating high frequency plasma in a gap, a DC power supply 6 for supplying power to the high voltage power supply 2 and the high frequency AC power supply 3, and a control device 7 for controlling the operation of the high voltage power supply 2 and the high frequency AC power supply 3 And have.

The high voltage power supply 2 includes a transformer 21, a semiconductor switch 22, and a diode 23. The transformer 21 has a primary winding 21 a whose one end is connected to the positive electrode of the DC power supply 6 and whose other end is connected to one end of the semiconductor switch 22, and one whose other end is connected to the first electrode 1 a of the spark plug 1. And a winding 21b. The diode 23 has an anode connected to one end of the secondary winding 21 b of the transformer 21 and a cathode connected to one end of the primary winding 21 a of the transformer 21. The diode 23 functions as a backflow prevention diode that prevents the power of the DC power supply 6 from being directly applied to the spark plug 1. The other end of the semiconductor switch 22 is connected to the ground level portion GND of the vehicle held at the ground level potential.

The transformer 21 and the semiconductor switch 22 constitute a flyback converter, and by controlling the on / off of the semiconductor switch 22, it is possible to boost the DC voltage. The high voltage power supply 2 may be any one that can apply a high voltage to the spark plug 1, and may have a configuration other than the flyback converter shown in FIG. 2.

The high frequency AC power supply 3 converts DC power to AC power and outputs it to the spark plug 1, and DC that converts DC voltage to a predetermined voltage value and outputs it to the DC / AC converter 4 And a DC / DC converter 5. The DC / AC conversion device 4 includes a full bridge inverter circuit, a step-up transformer 45, a resonance inductor 46 and a resonance capacitor constituting a resonance circuit, and a current detection means 48.

The full bridge inverter circuit is provided with four

semiconductor switches

41, 42, 43, 44 that constitute four sides of the bridge circuit. The connection point of the semiconductor switch 41 and the semiconductor switch 43 is connected to the positive output terminal of the DC / DC conversion device 5, and the connection point of the semiconductor switch 42 and the semiconductor switch 44 is on the negative side of the DC / DC conversion device 5. It is connected to the ground level site GND via a terminal.

The step-up transformer 45 includes a primary winding 45a and a secondary winding 45b. One end of the primary winding 45a is connected to a series connection point of the semiconductor switch 41 and the semiconductor switch 42 of the full bridge inverter circuit, The other end of the winding 45 a is connected to a series connection point of the semiconductor switch 43 and the semiconductor switch 44. One end of the secondary winding 45 b of the step-up transformer 45 is connected to one end of the resonant inductor 46, and the other end of the secondary winding 45 b is connected to the second electrode 1 b of the spark plug 1. The other end of the resonant inductor 46 is connected to one end of the resonant capacitor 47. The other end of the resonant capacitor 47 is connected to the first electrode 1 a of the spark plug 1.

The DC / AC conversion control circuit 49 inputs a gate signal generated based on a command from the control device 7 to the gate terminals of the four

semiconductor switches

41, 42, 43, 44 of the full bridge inverter circuit. The on / off operation of the semiconductor switches 41, 42, 43, 44 is controlled. The semiconductor switch 41 and the semiconductor switch 44 are simultaneously turned on and simultaneously turned off. The semiconductor switch 43 and the semiconductor switch 42 are simultaneously turned on and simultaneously turned off. When the semiconductor switch 41 and the semiconductor switch 44 are simultaneously turned on, the semiconductor switch 43 and the semiconductor switch 42 are simultaneously turned off. When the semiconductor switch 43 and the semiconductor switch 42 are simultaneously turned on, the semiconductor switch 41 and the semiconductor switch 42 are simultaneously turned on. The semiconductor switch 44 is simultaneously turned off.

The full bridge inverter circuit is inputted to the connection point between the semiconductor switch 41 and the semiconductor switch 43 by the four

semiconductor switches

41, 42, 43, 44 being controlled by the DC / AC conversion control circuit 49 as described above. The DC voltage is converted to an AC voltage and output to the primary winding 45 a of the step-up transformer 45. The DC / AC conversion device 4 only needs to be able to convert a DC voltage to an AC voltage, and may have another configuration other than the full bridge inverter circuit shown in FIG.

The boosting transformer 45 is provided to boost the output voltage of the high frequency AC power supply 3. The resonant inductor 46 and the resonant capacitor 47 constitute a resonant circuit, and shapes the output power output from the secondary winding 45 b of the step-up transformer 45 into a sine wave. If the same function as the resonant inductor 46 can be realized using the leakage inductance of the step-up transformer 45, the resonant inductor 46 may not be provided.

The current detection means 48 measures the output current of the DC / AC converter 4 and the capacitive discharge current associated with the dielectric breakdown in the gap between the first electrode 1 a and the second electrode 1 b of the spark plug 1. The current detection means 48 is formed of, for example, a current transformer, but may have a function of detecting a current like a shunt resistor. The DC / AC conversion control circuit 49 includes a drive circuit and the like configured by an integrated circuit or a semiconductor switch, and the semiconductor switch of the DC / AC conversion device 4 as described above based on the command signal from the control device 7 41, 42, 43, 44 are driven to control the power conversion operation of the DC / AC converter 4.

The DC / DC conversion device 5 includes an inductor 51, a diode 52, a power supply capacitor 54, a semiconductor switch 53, a DC / DC conversion control circuit 56, and a voltage detection unit 55. One end of the inductor 51 is connected to the positive electrode of the DC power supply 6 and the other end is connected to the anode of the diode 52. The cathode of the diode 52 is connected to the positive input terminal of the DC / AC converter 4 There is. One end of the power supply capacitor 54 is connected to the cathode of the diode 52, and the other end is connected to the ground level portion GND.

One end of the semiconductor switch 53 is connected to the series connection point of the inductor 51 and the diode 52, and the other end is connected to the ground level portion GND. The voltage detection means 55 is provided at the positive output terminal of the DC / DC conversion device 5, and detects the charging voltage V2 of the power supply capacitor 54. The DC / DC conversion control circuit 56 controls the on / off operation of the semiconductor switch 53 based on the detection value of the charging voltage V2 of the power supply capacitor 54 detected by the voltage detection means 55. The DC / DC conversion control circuit 56 is configured by a drive circuit or the like including an integrated circuit or a semiconductor switch, and controls the power conversion operation of the DC / DC conversion device 5 based on a command signal from the control device 7.

The inductor 51, the diode 52, and the semiconductor switch 53 constitute a boost chopper circuit. The DC power supply 6 generates, for example, an output voltage of 12 [V] as a vehicle-mounted power supply. The above-described step-up chopper circuit boosts the 12 [V] output voltage of the DC power supply 6 to several tens [V] to several hundreds [V] to charge the power supply capacitor 54. The DC / DC conversion control circuit 56 turns on and off the semiconductor switch 53 when the charging voltage V2 of the power supply capacitor 54 is less than the output voltage command value Vb, and the power supply capacitor 54 is operated by the step-up chopper circuit 50. The charging is performed, and the operation of the semiconductor switch 53 is stopped when the charging voltage V2 of the power supply capacitor 54 is equal to or higher than the output voltage command value Vb, and the charging of the power supply capacitor 54 by the step-up chopper circuit 50 is stopped.

The charging voltage V2 of the power supply capacitor 54 decreases when AC power is output from the DC / AC converter 4 to the spark plug 1 mainly by the power conversion operation of the DC / AC converter 4. However, since the charge stored in the power supply capacitor 54 is gradually discharged also from the connected semiconductor switch 53 or the like, the DC / AC conversion device 4 does not operate with the charging voltage V2 of the power supply capacitor 54. But it will decline gradually. However, even if AC power is not output to the spark plug 1, if the charging voltage V2 of the power supply capacitor 54 becomes less than the output voltage command value Vb, the semiconductor switch 53 of the DC / DC conversion device 5 repeatedly operates and stops. The charge voltage V2 of the power supply capacitor 54 is maintained at the output voltage command value Vb.

The DC / DC conversion device 5 may be any device as long as it can convert the output voltage of the DC power supply 6 into any predetermined voltage, and may have a configuration other than the step-up chopper circuit 50 shown in FIG.

The control device 7 controls the operation of the high voltage power supply 2, the DC / AC conversion device 4, and the DC / DC conversion device 5, and detects the current of the target location by the current detection unit 48. The control device 7 outputs an ignition command signal for instructing the timing for igniting the fuel in the combustion chamber of the internal combustion engine for each ignition cycle. Further, the control device 7 controls the timing of outputting the ignition command signal in accordance with the environment and the operating condition of the internal combustion engine so that the combustion occurs at the optimum timing for the internal combustion engine.

The ignition command signal may be input to the ignition device 10 from the outside of the control device 7. In this case, the ignition operation is performed according to the externally input ignition command signal.

The control device 7 controls the power conversion operation of the DC / DC conversion device 5 by the DC / DC conversion permission signal, and permits the power conversion operation when the DC / DC conversion permission signal is at high level. When the conversion enable signal is at low level, the power conversion operation is inhibited.

Further, the control device 7 controls the power conversion operation of the DC / AC conversion device 4 by the DC / AC conversion operation period signal, and performs the power conversion operation when the DC / AC conversion operation period signal is high level, When the DC / AC conversion operation period signal is low, the power conversion operation is stopped. The controller 7 is configured of, for example, an engine control unit or a microcomputer.

The semiconductor switches 22, 41, 42, 43, 44, 53 used in the high voltage power supply 2, the DC / DC conversion device 5, and the DC / AC conversion device 4 may be semiconductor switches. For example, an IGBT (Insulated-Gate Bipolar Transistor) or a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) may be used as the semiconductor switch described above.

Next, an operation sequence of the ignition device 10 according to the first embodiment of the present invention configured as described above will be described. FIG. 3 is a timing chart showing a schematic operation sequence of the ignition device in accordance with Embodiment 1 of the present invention, wherein "a" is an ignition command signal, "b" is a drive control signal of semiconductor switch 22, "c". Is the voltage applied to the spark plug 1, "d" is the DC / AC conversion operation period signal, "e" is the detection value I1 of the current detection means 48, "f" is the DC / DC conversion permission signal, and "g" is DC / DC. The output current of the DC converter 5 and "h" indicate the charging voltage of the power supply capacitor 54, respectively. The horizontal axis of FIG. 3 shows time. FIG. 4 is a flow chart showing an operation sequence of the ignition device in accordance with the first embodiment of the present invention.

In FIGS. 1 to 4, first, at step S01, the control device 7 of the ignition device 10 determines the content of the operation according to the ignition command signal output for each ignition cycle Ti. When the ignition command signal shown in “a” of FIG. 3 is at the high level Hi, the ignition device 10 starts a series of ignition operations to generate combustion in the combustion chamber of the internal combustion engine. When the ignition command signal shown to "a" of FIG. 3 is low level Lo, the power conversion operation | movement by DC / DC converter 5 is permitted, and DC / DC converter 5 operate | moves as needed.

At timing t1 shown in FIG. 3, the control device 7 switches the DC / DC conversion permission signal shown in "f" to low level Lo according to the ignition command signal shown in "a" in FIG. The power conversion operation of the device 5 is prohibited. This stage corresponds to step S02. Thereby, the switching operation of the semiconductor switch 53 of the DC / DC conversion device 5 is stopped, and the power supply capacitor 54 is not supplied with power.

Thereafter, in step S03, the control device 7 causes the semiconductor switch 22 in the high voltage power supply 2 to conduct in order to cause the spark plug 1 to generate a high voltage by the high voltage power supply 2. As a result, current flows through the primary winding 21 a of the transformer 21 of the high voltage power supply 2, and magnetic flux is accumulated in the iron core of the transformer 21.

In step S04, at timing t2 shown in FIG. 3, the control device 7 shuts off the semiconductor switch 22 of the high voltage power supply 2 in response to the change of the ignition command signal shown at "a" from high level Hi to low level Lo. Do. The timing t2 is a timing at which energy sufficient to apply the dielectric breakdown voltage to the spark plug 1 is accumulated in the iron core of the transformer 21. The time required from the timing t1 to the timing t2 is measured in advance for each operating condition of the internal combustion engine, and recorded in advance in a memory provided inside the control device 7.

When the semiconductor switch 22 of the high voltage power supply 2 is shut off, the energy of the magnetic flux stored in the transformer 21 is released, and an induced voltage is generated in the secondary winding 21b of the transformer 21. Since the energy of the magnetic flux stored in the transformer 21 is gradually released, the applied voltage V1 of the spark plug 1 shown in "c" of FIG. 3 increases in the direction of negative level with the passage of time from 0 [V]. . Although a negative voltage is applied to the spark plug 1 in the circuit configuration of FIG. 2, the circuit may be configured to apply a positive voltage.

Next, at timing t3 shown in FIG. 3, the applied voltage V1 of the spark plug 1 shown in “c” of FIG. 3 reaches the dielectric breakdown voltage Va, and the first electrode 1a and the second electrode 1b of the spark plug 1 Breakdown occurs in the air gap between When dielectric breakdown occurs in the gap between the electrodes of the spark plug 1, a large capacity discharge current instantaneously flows through the spark plug 1.

The capacitive discharge current flowing to the spark plug 1 is a release of the charge that has been charged in the resonant capacitor 47 connected to the spark plug 1 and the parasitic capacitance in the vicinity of the spark plug 1. The capacitance discharge current flowing to the spark plug 1 increases as the capacitance of the capacitor causing the capacitance discharge current increases. Therefore, in the ignition device 10 according to the first embodiment of the present invention, the resonance capacitor 47 causes the discharge. Capacity discharge current is particularly large. The capacitive discharge current also flows through a path constituted by the spark plug 1, the step-up transformer 45, the resonant inductor 46 and the resonant capacitor 47.

As a result, a part of the capacitive discharge current also flows into the high frequency AC power supply 3 through the step-up transformer 45, and is connected in parallel to the semiconductor switches 41, 42, 43, 44 in parallel, or for power supply It is consumed by refluxing the condenser 54 and the like. The controller 7 takes in the detection value I1 of the current detection means 48 and measures the current value of the capacitive discharge current based on the detection value I1.

Next, at timing t4 shown in FIG. 3, the control device 7 attenuates the peak value of the detection value I1 of the current detection means 48 to less than the predetermined first predetermined value Ia and the second predetermined value Ib. To judge that. This stage corresponds to step S05. The predetermined first predetermined value Ia is set as a value that causes the voltage detection means 55 to generate a detection error when the current value of the capacitive discharge current is equal to or greater than the first predetermined value Ia.

If the current value of the capacitive discharge current is greater than or equal to the second predetermined value Ib, the aforementioned second predetermined value Ib is not detected in the output current of the DC / AC conversion device 4 , And the detection value of the current detection means 48 for detecting the output current of the DC / AC conversion device 4 is set as a value causing a detection error. The second predetermined value Ib is preferably set to 1/2 or less of the output current command value Ic of the DC / AC conversion device 4. When the controller 7 determines that the peak value of the capacitive discharge current is attenuated to less than the first predetermined value Ia and the second predetermined value Ib, the controller 7 determines that the output of the high voltage power supply 2 has stopped and the next Move to action.

FIG. 5 is a flow chart showing an operation sequence of the ignition device in accordance with the first embodiment of the present invention, and shows a flow chart of a detailed operation sequence of step S05 in FIG. In the flow shown in FIG. 5, the judgment described below is performed using the detection value I1 of the current detection means 48. That is, when the peak value of the detection value I1 of the current detection means 48 becomes equal to or more than the first predetermined value Ia or the second predetermined value Ib after the timing t1 of FIG. Detection of the occurrence of capacitive discharge current due to dielectric breakdown in the gap between the This stage corresponds to step S51A.

FIG. 7 is an explanatory diagram for explaining the operation of the ignition device according to the first embodiment of the present invention, showing an example of the capacitive discharge current and explaining the determination based on the flowchart of FIG. The capacitive discharge current is an alternating current, the frequency of which is mainly the resonant frequency of the resonant inductor 46 and the resonant capacitor 47, so it has a cycle of [1 / resonant frequency] and produces positive and negative peak values for each cycle. In step S52A of FIG. 5, the control device 7 compares the detection value I1 of the current detection means 48 with a predetermined first predetermined value Ia also after step S51A in FIG.

That is, in step S52A in FIG. 5, as shown in FIG. 7, the detected value I1 of the capacitive discharge current detected by the current detecting means 48 is compared with the first predetermined value Ia for each cycle of the capacitive discharge current, As shown in the cycle T2, if it is not detected that the detected value I1 of the capacitive discharge current becomes equal to or greater than the first predetermined value Ia, it is determined that the capacitive discharge current has attenuated to less than the first predetermined value Ia. In period T1 shown in FIG. 7, it is determined that the detected value I1 of the capacitive discharge current is equal to or greater than the first predetermined value Ia, and in this case, the capacitive discharge current is not attenuated to less than the first predetermined value Ia. Do.

Next, in step S53A of FIG. 5, the control device 7 compares the detected value I1 of the capacitive discharge current with a predetermined second predetermined value Ib. Also in this step S53A, as in the cycle T3 shown in FIG. 7, if it can not be detected that the detected value I1 becomes equal to or more than the second predetermined value Ib every one cycle of the capacitive discharge current, the capacitive discharge current is second It is determined that it has fallen below the predetermined value Ib of. In the cycles T1 and T2, the detected value I1 of the capacitive discharge current is equal to or greater than the second predetermined value Ib. At this time, it is determined that the capacitive discharge current is not attenuated to less than the second predetermined value Ib. The order of step S52A and step S53A may be first.

FIG. 6 is a flowchart showing an operation sequence of the ignition device in accordance with the first embodiment of the present invention, and shows a flowchart of another detailed operation sequence of step S05 in FIG. In FIG. 6, in step S51B, an elapsed time ta from the timing t2 when the ignition command signal shown in “a” of FIG. 3 becomes the low level Lo is measured, and the elapsed time ta is a predetermined time Δt or more. It is determined that the time when it has become timing t4. As the predetermined time Δt, for example, the time required for the capacitive discharge current to attenuate to less than the first predetermined value Ia and the second predetermined value Ib from the fall of the ignition command signal at the timing t2 is set.

In addition, as a method of determining that the peak value of the capacitive discharge current after occurrence of dielectric breakdown in the gap between the electrodes of the spark plug 1 is attenuated to less than the first predetermined value Ia and the second predetermined value Ib, Any method may be used as long as the same effect as the method described in FIG. 7 is obtained.

Since the above-mentioned capacitive discharge current has a high frequency of MHz order or more, when flowing into the high frequency alternating current power supply 3, voltage oscillation is caused to the reference potential of the high frequency alternating current power supply 3 by parasitic inductance such as wiring. Since the voltage oscillation of the reference potential is superimposed on the voltage value of each part, the voltage oscillation of the reference potential is superimposed also on the signal of the sensor or the like, and an error occurs in the detection value of the sensor or the like.

For example, when voltage oscillation is superimposed on the detection value of the voltage detection means 55, the control device 7 can read the minimum value of the oscillation detection value and detect the charging voltage V2 of the power supply capacitor 54 smaller than it actually is. There is sex. As a result, the DC / DC conversion device 5 supplies a power larger than necessary to the power supply capacitor 54, so the charging voltage V2 of the power supply capacitor 54 becomes larger than the voltage command value Vb. When the charging voltage V2 of the power supply capacitor 54 becomes larger than the originally intended voltage command value Vb, the switching loss of the semiconductor switch of the DC / AC conversion device 4 and the like increase and the power loss increases.

However, in the ignition device 10 according to the first embodiment of the present invention, the high voltage power supply 2 is operated and the voltage is applied to the spark plug 1 after the power conversion operation of the DC / DC conversion device 5 is stopped. The DC / DC conversion device 5 stops the power conversion operation until the capacity discharge current attenuates to less than the predetermined first predetermined value Ia and the second predetermined value Ib. Therefore, excessive power supply to the power supply capacitor 54 does not occur regardless of the erroneous detection of the voltage detection means 55 due to the inflow of the capacitive discharge current. Therefore, since the error of the detection value of the voltage detection means 55 can be suppressed, the DC / DC conversion device 5 can be prevented from outputting an electric power larger than necessary, and the increase of the power loss of the high frequency AC power supply 3 can be prevented. .

At timing t5 after a predetermined delay time td1 has elapsed from timing t4 shown in FIG. 3, the control device 7 sends the DC / AC conversion operation period signal shown in FIG. Output at high level Hi. The DC / AC conversion control circuit 49 converts the energy charged in the power supply capacitor 54 into AC power by the DC / AC converter 4, and supplies the AC power to the spark plug 1. This stage is step S06 in FIG. As a result, high frequency plasma is generated in the spark plug 1. Here, the delay time td1 is, for example, about 50 [μs]. The shorter the delay time td1, the lower the discharge maintaining voltage of the spark plug 1 becomes.

The high frequency AC power supply 3 supplies AC power to the spark plug 1 for a time tac1 required for ignition shown in FIG. At this time, since the DC / DC conversion device 5 stops the power conversion operation, the charging voltage V2 of the power supply capacitor 54 shown by “h” in FIG. 3 gradually decreases.

Here, the ignition performance using the high frequency plasma generally improves as the output current increases, and the ignition can be performed even in an environment where it is difficult to burn. On the other hand, when the output current of the high frequency plasma is increased, the loss of the ignition device and the deterioration of the spark plug occur. Therefore, in an igniter using high frequency plasma, it is necessary to control the output current appropriately. Therefore, the control device 7 controls the frequency of the AC power output from the DC / AC conversion device 4 so that the peak value of the detection value I1 of the current detection means 48 approaches the output current command value Ic. The output current of the DC / AC conversion device 4 increases when the resonant frequencies of the resonant inductor 46 and the resonant capacitor 47 and the frequency of the AC power become close to each other, and decrease as they are distant from each other.

Thus, when the high voltage power supply 2 generates a high voltage and the insulation breakdown occurs in the gap between the electrodes of the spark plug 1 while the high frequency AC power supply 3 outputs AC power, the DC / AC conversion device The capacitive discharge current is superimposed on the output current of 4. As a result, the current detection means 48 can not accurately detect the output current of the DC / AC conversion device 4, and it becomes difficult to accurately control the output current value of the DC / AC conversion device 4. As a result, power loss may increase due to excessive AC power output, spark plug deterioration may occur, or ignition failure may occur due to insufficient AC power output.

However, in ignition device 10 according to the first embodiment of the present invention, high voltage power supply 2 does not output a voltage as shown in FIG. 3, and the second predetermined value of capacitive discharge current as a predetermined allowable predetermined value Since the DC / AC conversion device 4 is controlled to perform the power conversion operation at the timing when it is smaller than the value Ib, the output current of the DC / AC conversion device 4 can be detected accurately. As a result, it is possible to prevent an increase in power loss due to excessive AC power output, deterioration of the spark plug, or occurrence of ignition failure due to insufficient output of AC power.

Further, part of the AC power output from the high frequency AC power supply 3 flows into the high frequency AC power supply 3 through the common ground level portion GND of the internal combustion engine. Since the alternating current has a high frequency on the order of MHz, when flowing into the high frequency alternating current power supply 3, voltage oscillation is caused to the reference potential of the high frequency alternating current power supply 3 by parasitic inductance such as wiring. Such voltage oscillation of the reference potential is superimposed on the voltage value of each part, and therefore is superimposed on the signal of the sensor or the like to cause an error in the detected value.

When voltage oscillation is superimposed on the detection value of the voltage detection means 55, the control device 7 reads the minimum value of the oscillation detection value and may detect the charging voltage V2 of the power supply capacitor 54 smaller than the actual value. is there. As a result, since the DC / DC conversion device 5 supplies a power larger than necessary to the power supply capacitor 54, the charging voltage V2 becomes larger than the voltage command value Vb. When the charging voltage V2 of the power supply capacitor 54 becomes larger than the originally intended voltage command value Vb, the switching loss of the semiconductor of the DC / AC conversion device 4 and the like increase and the power loss increases.

However, in the ignition device 10 according to the first embodiment of the present invention, the power conversion operation of the DC / DC conversion device 5 is stopped before the DC / AC conversion device 4 operates. Regardless of the erroneous detection of the voltage detection means 55, excessive power supply to the power supply capacitor 54 does not occur. Therefore, since the error of the detection value of the voltage detection means 55 can be suppressed, the DC / DC conversion device 5 is prevented from outputting an electric power larger than necessary, and the increase of the power loss of the high frequency AC power supply 3 is prevented. be able to.

Further, the current supplied from the DC / AC converter 4 to the spark plug 1 is proportional to the charging voltage V2 of the power supply capacitor 54. Therefore, when the voltage detection means 55 detects the charging voltage V2 smaller than the actual value due to an erroneous detection, an electric power larger than necessary is supplied to the electric power supply capacitor 54, and the charging voltage V2 of the electric power supply capacitor 54 is a voltage command As it becomes larger than the value Vb, a large current flows in the spark plug 1 to cause deterioration of the spark plug 1. Conversely, when the voltage detection means 55 detects the charging voltage V2 of the power supply capacitor 54 smaller than the actual value due to an erroneous detection, the necessary power is not supplied to the power supply capacitor 54 and the power supply capacitor 54 The charging voltage V2 becomes smaller than the voltage command value Vb, and the alternating current of the spark plug 1 runs short, causing an ignition failure.

However, in the ignition device 10 according to the first embodiment of the present invention, as described above, the DC / AC conversion device 4 operates when the power conversion operation of the DC / DC conversion device 5 is stopped. The erroneous detection of the means 55 can be prevented, and the charging voltage V2 of the power supply capacitor 54 can be controlled to follow the voltage command value Vb. As a result, the current value supplied to the spark plug 1 by the DC / AC conversion device 4 is prevented from becoming excessively large or excessively small, which contributes to the deterioration of the spark plug 1 and the prevention of defective ignition.

At timing t6 when only the time tac1 necessary for ignition has elapsed from timing t5 shown in FIG. 3, the control device 7 sets the DC / AC conversion operation period signal shown at "d" in FIG. 3 to low level Lo. Thereby, the DC / AC conversion control circuit 49 stops the power conversion operation of the DC / AC conversion device 4. This stage is step S07 in FIG. As a result, the high frequency plasma generated in the spark plug 1 disappears.

At timing t6 shown in FIG. 3, the charging voltage V2 of the power supply capacitor 54 has dropped to a predetermined voltage value Vc. After stopping the power conversion operation of the DC / AC conversion device 4, the control device 7 switches the DC / DC conversion permission signal shown in “f” of FIG. 3 to high level Hi, and converts the power of the DC / DC conversion device 5. Allow the action. This stage is step S08 in FIG.

FIG. 8 is a flow chart showing an operation sequence of the DC / DC conversion device in the ignition device according to Embodiment 1 of the present invention. When the controller 7 is permitted to perform the power conversion operation, the DC / DC conversion device 5 operates according to the flowchart of FIG. In step S81 of FIG. 8, the DC / DC conversion control circuit 56 determines the state of the DC / DC conversion permission signal shown in “f” of FIG. 3 and the charging voltage V2 of the power supply capacitor 54 and the DC / DC conversion device. Comparison with the output voltage command value Vb of 5 is performed. When the DC / DC conversion permission signal shown in “f” of FIG. 3 is high level Hi and the charging voltage V2 of the power supply capacitor 54 is smaller than the output voltage command value Vb, the DC / DC conversion control circuit 56 The switch 53 is operated to output DC power to the power supply capacitor 54. This stage is step S82 in FIG. When the DC / DC conversion permission signal is low level Lo or the charging voltage V2 of the power supply capacitor 54 is equal to or higher than the output voltage command value Vb, the DC / DC conversion control circuit 56 stops the semiconductor switch 53 and the power supply capacitor Stop the supply of DC power to 54. This stage is step S83 in FIG.

The control device 7 permits the power conversion operation by the DC / DC conversion device 5 until the ignition command signal shown in FIG. 3A becomes high level Hi, and the charging voltage V2 of the power supply capacitor 54 is the output voltage command value Control to be maintained at Vb.

In an actual igniter, various elements are connected in parallel with the power supply capacitor 54. Therefore, in the power supply capacitor 54, the charge component is gradually discharged by their resistance components, and the charge voltage V2 decreases. Therefore, the semiconductor switch 53 of the DC / DC conversion device 5 repeatedly operates and stops to supply power so as to maintain the charging voltage V2 of the power supply capacitor 54. This sequence operation is repeated for each ignition cycle Ti of the internal combustion engine. A typical ignition cycle Ti is about 10 ms to 100 ms. Further, the output period Tac of the output current from the DC / AC conversion device 4 is about 100 [μs].

FIG. 9A is an explanatory view showing a condition when the DC / DC conversion device performs the power conversion operation, and FIG. 9B is a condition when the DC / DC conversion device performs the power conversion operation and a detection error of the voltage detection means It is an explanatory view showing a relation. In FIG. 9B, “a” is a capacitive discharge current, “b” is an output current of the DC / AC converter 4, “c” is an operation permitted state of the DC / DC converter 5, and “d” is a power supply capacitor 54. The charging voltage V2 of “e” indicates the detection value of the voltage detection means 55, respectively.

In FIG. 9A, under condition 1, the DC / DC conversion device 5 performs the power conversion operation as needed. Under the condition 2, the DC / DC conversion device 5 performs the power conversion operation in a period in which the capacity discharge current is smaller than a predetermined value. Under condition 3, the DC / DC conversion device 5 performs the power conversion operation in a period in which the DC / AC conversion device 4 does not output AC power to the spark plug. Under the condition 4, the DC / DC conversion device 5 performs the power conversion operation in a period in which the capacity discharge current is smaller than a predetermined value and in a period in which the DC / AC conversion device 4 does not output AC power to the spark plug 1. Do.

Here, as shown in FIG. 9B, the capacitive discharge current indicated by “a” is similarly applied to the gap between the electrodes of the spark plug 1 under any of the above-mentioned condition 1, condition 2, condition 3 and condition 4 The value immediately reaches the maximum value at the dielectric breakdown timing where dielectric breakdown occurs, and gradually attenuates while vibrating and becomes smaller than a predetermined value after a predetermined time. Also, the output current of the DC / AC conversion device 4 shown in “b” is constant at a timing slightly delayed from the dielectric breakdown timing in any of the above-mentioned condition 1, condition 2, condition 3 and condition 4 as well. It is illustrated as oscillating at an amplitude and frequency and flowing for a predetermined period of time.

Under the condition 1, as described above, the DC / DC conversion device 5 performs the power conversion operation as needed. Here, as indicated by “c”, from the predetermined timing ta to the predetermined timing tb The DC / DC conversion device 5 is in the operation permitted state in a predetermined period A1.

Under the condition 2, as described above, the DC / DC conversion device 5 performs the power conversion operation in a period in which the capacity discharge current is smaller than a predetermined value, as shown by “c” here. In the period A2 of the timing ta to the timing tc and the period A3 of the timing td to the timing tb, the DC / DC conversion device 5 is in the operation permitted state. A period B1 from the timing tc to the timing td is an operation prohibited section of the DC / DC conversion device 5.

Under the condition 3, as described above, the DC / DC conversion device 5 performs the power conversion operation in a period in which the DC / AC conversion device 4 does not output the AC power to the spark plug 1. As shown in “,” the DC / DC conversion device 5 is in the operation permitted state in the period A4 of the timing ta to the timing te and the period A5 of the timing tf to the timing tb. A period B2 from the timing te to the timing tf is an operation prohibited section of the DC / DC conversion device 5.

Under the condition 4, as described above, the DC / DC conversion device 5 has a period in which the capacity discharge current is smaller than a predetermined value and a period in which the DC / AC conversion device 4 does not output AC power to the spark plug 1. Is the power conversion operation, and here, as shown in “c”, the DC / DC conversion device 5 is permitted to operate in the period A2 of the timing ta to the timing tc and the period A5 of the timing tf to the timing tb. It becomes a state. A period B3 from the timing tc to the timing tf is an operation prohibited section of the DC / DC conversion device 5.

As shown in FIG. 9B, under any of condition 1, condition 2, condition 3 and condition 4, since the high voltage power supply 2 generates dielectric breakdown in the gap between the electrodes of the spark plug 1, the capacitive discharge current is made in advance. As indicated by “e”, the voltage detected by the voltage detection means 55 is a voltage in a period until it attenuates to a value less than a predetermined value and a period in which the DC / AC conversion device 4 outputs AC power to the spark plug 1. The vibration is superimposed, and an error occurs in the detection value of the voltage detection means 55.

The period from when the high voltage power supply 2 generates dielectric breakdown in the gap between the electrodes of the spark plug 1 to the time when the capacity discharge current attenuates to less than a predetermined value, and the DC / AC conversion device 4 When the two periods with the period for outputting the AC power overlap, the respective vibrations are superimposed, so that the detection error of the voltage detection means 55 becomes larger as shown by “e”. Therefore, when the control device 7 reads the minimum value of the detection value of the voltage detection means 55 on which the voltage oscillation is superimposed, the charging voltage V2 of the power supply capacitor 54 is actually the output voltage command of the DC / DC conversion device 5 Even if the value is Vb, it is determined that V2 of the power supply capacitor 54 is smaller than the output voltage command value Vb.

As a result, if the DC / DC conversion permission signal shown in “f” of FIG. 3 is the high level Hi, the process proceeds from step S81 to step S82 in FIG. 9B, the charging voltage V2 of the power supply capacitor 54 becomes larger than the output voltage command value Vb of the DC / DC conversion device 5, as indicated by condition 1 in “e” of FIG. 9B. there is a possibility. As described above, when the output voltage V2 of the power supply capacitor 54 becomes larger than necessary, the switching loss and the like of the semiconductor switch of the high frequency AC power supply 3 are increased, and the power loss is increased.

Under the condition 2 shown in FIG. 9B, the power conversion operation of the DC / DC conversion device 5 is prohibited in a period B1 from the timing tc to the timing td when the capacitance discharge current shown in “a” attenuates to a predetermined value. The power conversion operation of the DC / DC conversion device 5 is stopped. Therefore, the control device 7 controls the power conversion operation of the DC / DC conversion device 5 in a period in which the capacity discharge current is smaller than a predetermined value. In this case, the charging voltage V2 of the power supply capacitor 54 is smaller than in the case of Condition 1, switching loss of the semiconductor switch of the high frequency AC power supply 3 is suppressed, and an increase in power loss is suppressed.

Under condition 3 shown in FIG. 9B, the power conversion operation of the DC / DC conversion device 5 is inhibited in a period B2 from the timing te to the timing tf when the output current of the DC / AC conversion device 4 shown in "b" flows. The power conversion operation of the / DC conversion device 5 is stopped. However, since the power conversion operation of DC / DC conversion device 5 is performed in a period in which the capacitive discharge current up to period B2 is larger than a predetermined value, power supply operation is performed compared to the case of Condition 2. The charging voltage V2 of the capacitor 54 becomes larger, the switching loss of the semiconductor switch of the high frequency AC power supply 3 becomes larger than that of the condition 2, and the power loss increases.

Under the condition 4 shown in FIG. 9B, DC / DC conversion is performed in a period B3 from the timing tc when the dielectric breakdown occurs to the timing tf when the output current of the DC / AC conversion device 4 does not flow. The power conversion operation of the device 5 is prohibited, and the DC / DC conversion device 5 stops the power conversion operation. Therefore, control device 7 performs the power conversion operation of DC / DC conversion device 5 in periods A2 and A5 in which the capacitive discharge current is smaller than the predetermined value and the output current of DC / AC conversion device 4 does not flow. Control to do In this case, the charging voltage V2 of the power supply capacitor 54 does not exceed the output voltage command value Vb, and switching loss and the like of the semiconductor switch of the high frequency AC power supply 3 are suppressed, and an increase in power loss is suppressed.

In the ignition device according to the first embodiment of the present invention, controlling the DC / DC conversion device 5 based on the condition 2 of FIG. 9B is a first basic technology. Specifically, in a period in which the detection value I1 of the current detection means 48 shown in "e" of FIG. 3 is smaller than the first predetermined value Ia, the controller 7 performs DC / DC shown in "f" of FIG. The conversion enable signal is set to high level Hi.

Thereby, during the power conversion operation of DC / DC conversion device 5, the capacitive discharge current does not flow into the reference potential of DC / DC conversion device 5, or the capacitive discharge current is minute. It is possible to suppress the error of the value. As a result, it is possible to prevent the DC / DC conversion device 5 from outputting power that is larger than necessary, and to prevent an increase in the power loss of the high frequency AC power supply 3.

Furthermore, in the ignition device according to the first embodiment of the present invention, controlling the DC / DC conversion device 5 based on the condition 4 of FIG. 9B is a second basic technology. Specifically, in a period in which the detection value I1 of the current detection means 48 shown in “e” of FIG. 3 is smaller than the first predetermined value Ia and the output current of the DC / AC conversion device 4 does not flow, 7 sets the DC / DC conversion permission signal shown in “f” of FIG. 3 to high level Hi.

Specifically, igniter 10 according to the first embodiment of the present invention is specifically a first device in which a capacitive discharge current associated with dielectric breakdown is predetermined after high voltage power supply 2 generates a voltage to spark plug 1. The power conversion operation of the DC / DC conversion device 5 is stopped in at least one of a period until it attenuates to the predetermined value Ia and a period in which the DC / AC conversion device 4 outputs AC power to the spark plug 1. In this case, control device 7 performs a period in which at least one of a period in which the capacity discharge current is smaller than a predetermined first predetermined value Ia and a period in which DC / AC conversion device 4 does not output AC power is The DC / DC converter 5 is controlled to perform the power conversion operation.

Thus, during the period when the DC / DC conversion device 5 performs the power conversion operation, the capacitance discharge current due to dielectric breakdown and the output current of the DC / AC conversion device 4 simultaneously flow into the reference potential of the DC / DC conversion device 5 And the detection error in the voltage detection means 55 can be suppressed. As a result, it is possible to prevent the DC / DC conversion device 5 from outputting an unnecessarily large power due to the influence of the detection error, and to prevent an increase in power loss.

Further, in the ignition device 10 according to the first embodiment of the present invention, a period from when the high voltage power supply 2 generates the voltage in the spark plug 1 to the time when the capacitive discharge current accompanying the dielectric breakdown attenuates to a predetermined value. The power conversion operation of the DC / DC conversion device 5 may be stopped in both the period in which the DC / AC conversion device 4 outputs AC power to the spark plug 1 and the period in which the DC / AC conversion device 4 outputs AC power. FIG. 3 shows a timing chart in this case. That is, control device 7 controls the DC / DC conversion device both in a period in which the capacity discharge current is smaller than a predetermined first predetermined value Ia and in a period in which DC / AC conversion device 4 does not output AC power. 5 controls to perform the power conversion operation.

This prevents both of the capacitive discharge current due to dielectric breakdown and the output current of the DC / AC conversion device 4 from flowing into the DC / DC conversion device 5 during the power conversion operation of the DC / DC conversion device 5 The detection error of the voltage detection means 55 can be further suppressed. As a result, it is possible to prevent the DC / DC conversion device 5 from outputting power that is larger than necessary due to the influence of the detection error, and to prevent an increase in power loss.

In the ignition device 10 according to the first embodiment of the present invention, the control device 7 causes the DC / DC conversion device 5 to perform the power conversion operation during a period in which the capacity discharge current is smaller than the predetermined second predetermined value Ib. The DC / AC conversion device 4 is controlled to perform the power conversion operation during the period of stoppage. As a result, the capacitive discharge current is superimposed on the output current of the DC / AC conversion device 4 to prevent the current detection unit 48 from becoming undetectable, and the DC / AC conversion device using the detection value I1 of the current detection unit 48 Control of the output current of 4 is possible.

As a result, it is possible to prevent the deterioration of the spark plug due to the supply of an excessive current to the spark plug 1 and the deterioration of the ignition performance due to the shortage of the current. Here, the deterioration of the ignition performance may be, for example, deterioration of the fuel efficiency due to the reduction of the flame propagation speed, or increase of harmful substances of the exhaust gas due to the incomplete combustion.

Control device 7 has a period in which the capacity discharge current is smaller than predetermined first predetermined value Ia and second predetermined value Ib, and a period in which DC / DC conversion device 5 stops the power conversion operation. , DC / AC converter 4 can be controlled to perform a power conversion operation. As a result, as described above, it is prevented that detection can not be performed due to the capacitive discharge current being superimposed on the output current of the DC / AC conversion device 4, and the DC / AC conversion device 4 using the detection value I1 of the current detection means 48 Control of the output current of the

Further, the detection error of the voltage detection means 55 is prevented, and the DC / DC conversion device 5 does not output an excessive or excessively small power, and the charging voltage V2 of the power supply capacitor 54 is larger than the output voltage command value Vb or It can be prevented from becoming too small. Since the output current of the DC / AC converter 4 is proportional to the charging voltage V2 of the power supply capacitor 54, deterioration of the spark plug due to the supply of an excessive current by preventing the detection error of the voltage detection means 55 Also, it is possible to prevent the deterioration of the ignition performance due to the lack of current. Therefore, the output current to the spark plug 1 of the DC / AC conversion device 4 can be more accurately controlled, and deterioration of the spark plug 1 due to the excessive current being supplied to the spark plug 1, and the spark plug 1 And the deterioration of the ignition performance due to the shortage of the current supplied to the

In the ignition device 10 according to Embodiment 1 of the present invention, the high voltage power supply 2 applies a voltage to the spark plug while the DC / DC conversion device 5 and the DC / AC conversion device 4 do not perform the power conversion operation. Cause insulation breakdown. As a result, in the power conversion operation of the DC / DC conversion device 5, a part of the capacitive discharge current can be prevented from flowing into the DC / DC conversion device 5, and the detection error of the voltage detection means 55 can be suppressed. In addition, it is possible to prevent the capacitive discharge current from being superimposed on the output current of the DC / AC conversion device 4 and to control the output current of the DC / AC conversion device 4 using the detection value I1 of the current detection means 48. Therefore, while preventing the increase in the power loss of high frequency alternating current power supply 3, it contributes to the prevention of degradation of ignition plug 1 and ignition performance fall.

In the ignition device 10 according to the first embodiment of the present invention, the high voltage power supply 2, the DC / AC conversion device 4, and the DC / DC conversion device 5 are controlled according to the ignition command signal shown in "a" of FIG. Do. The ignition command signal is controlled to ignite at a timing suitable for the environment and operating conditions of the internal combustion engine, and therefore, ignition can be easily performed at an optimal timing by operating the igniter 10 according to the ignition command signal.

In the ignition device 10 according to the first embodiment of the present invention, as shown in FIG. 3, in the period from when the power conversion operation of the DC / AC conversion device 4 is performed until the next ignition command signal is output, The DC / DC conversion device 5 performs the power conversion operation. Thereby, the charging voltage V2 of the power supply capacitor 54 at the timing t1 is maintained substantially at the same level as the command value Vb, so that the applied voltage V1 of the spark plug at the timing t5 can be equal to or higher than the discharge maintaining voltage. It is possible to prevent a decrease in ignition performance due to the inability of the high frequency plasma to be generated in the spark plug 1.

Second Embodiment
Next, an ignition device according to Embodiment 2 of the present invention will be described. The circuit configuration of the ignition device according to the second embodiment of the present invention is the same as that of the first embodiment. Therefore, the same reference numerals are given to the components corresponding to the first embodiment and the description will be omitted. In the igniter according to the second embodiment of the present invention, ignition of fuel by discharge plasma is performed even after occurrence of dielectric breakdown. Therefore, discharge plasma can be generated for a long time in the spark plug, and fuel can be ignited even at a later timing after dielectric breakdown, which can contribute to the improvement of the ignition performance. In the igniter according to the second embodiment of the present invention, by outputting AC power from the high frequency AC power supply 3 for a long time, it is possible to ignite the flame retardant fuel mixture and to accelerate the combustion speed.

On the other hand, in order to output AC power from the high frequency AC power supply 3 to the spark plug 1 to continue high frequency plasma for a long time, much energy is consumed. Therefore, the capacitance of the power supply capacitor 54 is made sufficiently large to suppress a drop in the charging voltage V2 of the power supply capacitor 54 during high frequency plasma generation, and discharge of the applied voltage V1 of the spark plug 1 is maintained. It is necessary to prevent the voltage from falling below. However, for that purpose, the power supply capacitor 54 needs to be large, and the igniter becomes large.

In the second embodiment of the present invention, the DC / AC conversion device 4 of the high frequency alternating current power supply 3 once generates the high frequency plasma for a long time without increasing the capacitance of the power supply capacitor 54 of the ignition device. AC power is intermittently outputted to the spark plug 1 a plurality of times in the ignition cycle Ti.

Next, an operation sequence of the ignition device 10 according to the second embodiment of the present invention will be described. FIG. 10 is a timing chart showing a schematic operation sequence of the ignition device in accordance with Embodiment 2 of the present invention, and FIG. 11 is a flow chart showing an operation sequence of the ignition device in accordance with Embodiment 2 of the present invention. The operation from timing t1 to t6 in FIG. 10 is similar to the operation from timing t1 to t6 in FIG. 3 described above.

At timing t6 shown in FIG. 10, the control device 7 stops the power conversion operation of the DC / AC conversion device 4 and permits the power conversion operation of the DC / DC conversion device 5. This stage is step S08 in FIG. Thereby, the DC / DC conversion device 5 performs the power conversion operation so that the charging voltage V2 of the power supply capacitor 54 becomes equal to or higher than the output voltage command value Vb according to the above-mentioned flow chart of FIG.

Thereafter, as a result of the determination in step S01 of FIG. 11, if the output of the ignition command signal shown in “a” of FIG. 10 is not high level Hi, the controller 7 at timing t7 when only the pause period ts1 has elapsed from timing t6. Outputs the DC / AC conversion operation period signal as high level Hi. At the same time or substantially simultaneously with the high level Hi of the DC / AC conversion operation period signal, the control device 7 sets the DC / DC conversion permission signal indicated by “f” to the low level Lo, and the operation of the DC / DC conversion device 5 Prohibit This stage is step S10 in FIG. At this time, the charging voltage V2 of the power supply capacitor 54 indicated by “h” in FIG. 10 may not be equal to or higher than the output voltage command value Vb. A typical pause period ts1 is about 50 [μs].

At the same time or substantially simultaneously with the inhibition of the operation of the DC / DC conversion device 5 in step S10, the control device 7 performs the power conversion operation by the DC / AC conversion device 4. Thereby, the DC / AC converter 4 supplies an alternating current to the spark plug 1 to generate high frequency plasma. This stage is step S11 in FIG. The high frequency AC power supply 3 continues to supply AC power to the spark plug 1 for an AC power output period tac2 necessary for ignition. At this time, since the DC / DC conversion device 5 stops the power conversion operation, the charging voltage V2 of the power supply capacitor 54 gradually decreases.

Next, as shown in FIG. 10, at timing t8 when only the AC power output period tac2 has elapsed from timing t7, the control device 7 sets the DC / AC conversion operation period signal indicated by "d" to the low level Lo. Thereby, the DC / AC conversion control circuit 49 stops the power conversion operation of the DC / AC conversion device 4. This stage is step S12 in FIG. A typical AC power output period tac2 is about 50 [μs].

Next, at the same time or substantially simultaneously with stopping the power conversion operation of the DC / AC conversion device 4, the control device 7 switches the DC / DC conversion permission signal shown in “f” to high level Hi at timing t8. The power conversion operation of the DC / DC conversion device 5 is permitted. This stage is step S08 in FIG.

The ignition device 10 according to the second embodiment of the present invention performs the sequence operation from timing t1 to timing t8 shown in FIG. 10 by the ignition command signal shown in "a" of FIG. 10 and the DC / AC conversion shown in "d". It repeats every ignition cycle Ti of the internal combustion engine according to the operation period signal.

As described above, in the ignition device 10 according to the second embodiment of the present invention, after the DC / AC conversion device 4 of the high frequency AC power supply 3 outputs AC power in one ignition cycle Ti, the predetermined idle period is After being provided, AC power is output to the spark plug 1 again. As a result, high-frequency plasma can be generated at a later timing from the occurrence of dielectric breakdown in the gap between the electrodes of the spark plug 1 with less power consumption than in the case where AC power is continuously output without providing a pause period. Thus, the enlargement of the power supply capacitor 54 due to the increase in capacity can be prevented.

In the ignition device 10 according to Embodiment 2 of the present invention, the power conversion operation of the DC / DC conversion device 5 is performed during the idle period of the power conversion operation of the DC / AC conversion device 4. As a result, it is not necessary to cover the power consumption of the DC / AC conversion device 4 in one ignition cycle with only the energy pre-charged in the power supply capacitor 54. Therefore, the large size of the power supply capacitor 54 is increased. Can be prevented.

Further, in the ignition device 10 according to the second embodiment of the present invention, the DC / AC conversion device 4 and the DC according to the DC / AC conversion operation period signal until the ignition command signal becomes high level Hi and shifts to the next ignition cycle. The operation of the / DC conversion device 5 is controlled. Therefore, the AC power output period and the idle period of the DC / AC conversion device 4 may be provided plural times. Next, as an example, the timing operation when the AC power output period of the DC / AC conversion device 4 and the idle period are each increased once will be described with reference to FIG.

FIG. 12 is another timing chart showing a schematic operation sequence of the ignition device in accordance with Embodiment 2 of the present invention. The operation up to the timing t8 in FIG. 12 is the same as that in FIG. At timing t8, the control device 7 stops the power conversion operation of the DC / AC conversion device 4 and permits the power conversion operation of the DC / DC conversion device 5. This stage is step S08 in FIG. Thus, the DC / DC conversion device 5 performs the power conversion operation according to the above-described flowchart of FIG. 8 so that the charging voltage V2 of the power supply capacitor 54 is controlled to be the output voltage command value Vb or more.

In FIG. 12, the control device 7 outputs the DC / AC conversion operation period signal indicated by "d" at the high level Hi at timing t9 when only the pause period ts2 has elapsed from the timing t8. At the same time or substantially simultaneously with the high level Hi of the DC / AC conversion operation signal, the control device 7 sets the DC / DC conversion permission signal shown in “f” to low level Lo, and the operation of the DC / DC conversion device 5 Ban. This stage is step S10 in FIG. A typical pause period ts2 is about 50 [μs].

In step S10, the operation of the DC / DC conversion device 5 is prohibited, and in step S11, the control device 7 performs the power conversion operation by the DC / AC conversion device 4. Thereby, the DC / AC converter 4 supplies an alternating current to the spark plug 1 to generate high frequency plasma. The high frequency AC power supply 3 continues to supply AC power to the spark plug 1 for an AC power output period tac3 necessary for ignition.

At timing t10 when only tac3 has elapsed from timing t9, the control device 7 sets the DC / AC conversion operation period signal indicated by "d" to the low level Lo. Thereby, the DC / AC conversion control circuit 49 stops the power conversion operation of the DC / AC conversion device 4. This stage is step S12 shown in FIG. A typical AC power output period tac3 is about 50 [μs]. While stopping the power conversion operation of the DC / AC conversion device 4, the control device 7 switches the DC / DC conversion permission signal shown in "f" to high level Hi, and permits the power conversion operation of the DC / DC conversion device 5. Do. This stage is step S08 in FIG.

In the operation sequence of the ignition device according to the second embodiment of the present invention described above, according to the DC / AC conversion operation period signal output from the control device 7 as from timing t6 to t8 and timing t8 to t10. The DC / AC conversion device 4 repeats output and stop of AC power multiple times in one ignition cycle. The AC power output period and the idle period of the DC / AC conversion device 4 may be provided a plurality of times.

As a result, in the ignition device according to the second embodiment of the present invention, the AC current is longer in the spark plug 1 for a longer time than when the AC power output period of the DC / AC converter 4 and the idle period are not provided multiple times. It can be output and can contribute to the improvement of the ignition performance.

Third Embodiment
Next, an ignition device according to a third embodiment of the present invention will be described. In the first embodiment described above, the DC / DC conversion device 5 is prevented from outputting excessive power by controlling the operation and stop of the DC / AC conversion device 4 and the DC / DC conversion device 5. However, in the ignition device according to the third embodiment, even when voltage oscillation is superimposed on the detection value of the voltage detection means 55, the voltage immediately before the voltage oscillation is superimposed on the DC / DC conversion control circuit 56. By controlling the DC / DC conversion device 5 using the detected value, the DC / DC conversion device 5 is prevented from outputting excessive power.

The circuit configuration of the ignition device according to the third embodiment of the present invention is the same as that of the first embodiment. Therefore, the same reference numerals are given to the components corresponding to the first embodiment and the description will be omitted. The DC / DC conversion device 5 performs the power conversion operation so that the charging voltage V2 of the power supply capacitor 54 becomes equal to or higher than the output voltage command value Vb according to the above-described flow chart of FIG. That is, when the DC / DC conversion permission signal is at the high level and the charging voltage V2 of the power supply capacitor 54 is smaller than the output voltage command value Vb, the DC / DC conversion control circuit 56 operates the semiconductor switch 53 to The DC power is output to the supply capacitor 54. When the DC / DC conversion permission signal is low or the charging voltage V2 is equal to or higher than the output voltage command value Vb, the DC / DC conversion control circuit 56 stops the semiconductor switch 53 and supplies DC power to the power supply capacitor 54. Stop.

Since various elements not shown in FIG. 2 are connected in parallel to the power supply capacitor 54, the power charged in the power supply capacitor 54 is always consumed. As a result, the charging voltage V2 of the power supply capacitor 54 is gradually reduced, so that the semiconductor switch 53 of the DC / DC conversion device 5 is operated even if the charging energy is not consumed by the power conversion operation of the DC / AC conversion device 4. Stopping is repeated and power is supplied so that the charging voltage V2 of the power supply capacitor 54 becomes equal to or higher than the output voltage command value Vb.

Next, an operation sequence of the ignition device 10 according to the third embodiment of the present invention will be described. FIG. 13 is a flow chart showing an operation sequence of the ignition device in accordance with Embodiment 3 of the present invention, and FIG. 14 is another timing chart showing a schematic operation sequence of the ignition device in accordance with Embodiment 3 of the present invention.

In FIG. 13 and FIG. 14, the control device 7 of the ignition device 10 determines the content of the operation of the ignition device 10 according to the ignition command signal output for each ignition cycle Ti shown in “a” of FIG. That is, in step S101 of FIG. 13, it is determined whether the signal level of the ignition signal is high level Hi or not. If it is high level Hi (YES), the fuel of the combustion chamber in the internal combustion engine is ignited as follows. A series of ignition operations to be described are started, and if it is low level Lo, the process returns to step S101.

When the process proceeds from step S101 to step S102, at timing t2 in FIG. 13, the control device 7 sets the capture stop signal of the voltage detection value shown in “g” in FIG. 14 to high level Hi in response to the fall of the ignition command signal. And the DC / DC conversion control circuit 56 is controlled so as to stop the acquisition of the detection value of the voltage detection means 55. The DC / DC conversion control circuit 56 holds the voltage detection value by the voltage detection means 55 at timing t2, and at timing t2 in a period until timing t4 when the acquisition stop signal of the voltage detection value becomes low level Lo. The operation of the DC / DC converter 5 is controlled based on the voltage detection value of

In step S103, the control device 7 causes the semiconductor switch 22 to conduct at timing t1 in order to cause the spark plug 1 to generate a high voltage by the high voltage power supply 2. As a result, current flows through the primary winding 21 a of the transformer 21 and magnetic flux is accumulated in the iron core of the transformer 21.

Next, at timing t2, the control device 7 shuts off the semiconductor switch 22 of the high voltage power supply 2 in response to the fall of the ignition command signal. This stage is step S104. The timing t2 is a timing at which energy sufficient to apply the breakdown voltage to the spark plug 1 is accumulated in the iron core of the transformer 21.

When the semiconductor switch 22 is shut off, the energy of the magnetic flux stored in the transformer 21 is released, and an induced voltage is generated in the secondary winding 21b. Since the energy of the magnetic flux is gradually released, the applied voltage V1 of the spark plug 1 shown by "c" increases to the negative side with the passage of time.

At timing t3, the output voltage V1 of the spark plug 1 reaches the dielectric breakdown voltage Va, and dielectric breakdown occurs in the gap between the opposing electrodes of the spark plug 1. As a result, a large capacity discharge current instantaneously flows between the electrodes of the spark plug 1, that is, the spark plug 1.

The capacitive discharge current is a release of the charge stored in the resonant capacitor 47 connected to the spark plug 1 and the parasitic capacitance in the vicinity of the spark plug 1. The capacitive discharge current increases as the capacitance of the causative capacitor increases. In the ignition device of the present invention, the capacitive discharge current caused by the resonant capacitor 47 is particularly large. The capacitive discharge current also flows through a path constituted by the spark plug 1, the step-up transformer 45, the resonant inductor 46 and the resonant capacitor 47.

As a result, a part of the capacitive discharge current also flows into the high frequency AC power supply 3 through the step-up transformer 45, and parallel diodes connected in parallel to the semiconductor switches 41, 42, 43, 44, the power supply capacitor 54, etc. It is consumed refluxing. The control device 7 takes in the detection value I1 of the current detection means 48 shown by "e" in FIG. 14, and measures the current value of the capacitive discharge current.

At timing t4, the controller 7 determines that the peak value of the detection value I1 of the current detection means 48 is attenuated to less than a first predetermined value Ia. This stage is step S105 in FIG. The predetermined first predetermined value Ia is a value that causes the voltage detection means 55 to generate a detection error when the current value of the capacitive discharge current is greater than or equal to the first predetermined value Ia. When the control device 7 determines that the peak value of the capacitive discharge current has decreased to less than the first predetermined value Ia, it determines that the output of the high voltage power supply 2 has stopped, and proceeds to the next operation.

After judging that the signal has been attenuated to less than the first predetermined value Ia determined in advance, the control device 7 switches the take-off stop signal of the voltage detection value shown in “g” of FIG. The DC conversion control circuit 56 is controlled to start the acquisition of the detection value of the voltage detection means 55. This stage is step S106 in FIG. As a result, the DC / DC conversion control circuit 56 controls the operation of the DC / DC conversion device 5 based on the detection value of the voltage detection means 55.

Since the above-mentioned capacitive discharge current has a high frequency of MHz order or more, when flowing into the reference potential of the high frequency alternating current power supply 3, voltage oscillation is caused to the reference potential of the high frequency alternating current power supply 3 by parasitic inductance such as wiring. Such voltage oscillation of the reference potential is superimposed on the voltage value of each part, and therefore is superimposed on the signal of the sensor or the like to cause an error in the detected value.

For example, when voltage oscillation is superimposed on the detection value of the voltage detection means 55, the control device 7 can take in the minimum value of the oscillation detection value and detect the charging voltage V2 of the power supply capacitor 54 smaller than it actually is. There is sex. As a result, the DC / DC conversion device 5 supplies a power larger than necessary to the power supply capacitor 54, so the charging voltage V2 of the power supply capacitor 54 becomes larger than the voltage command value Vb. When the charging voltage V2 of the power supply capacitor 54 becomes larger than the originally intended voltage command value Vb, the switching loss of the semiconductor of the DC / AC conversion device 4 and the like increase and the power loss increases.

However, in the ignition device according to the third embodiment of the present invention, the DC / DC conversion control circuit 56 functions as the voltage detection means 55 in a period in which voltage oscillation due to the capacitive discharge current is superimposed on the detection value of the voltage detection means 55. The DC / DC conversion device 5 is controlled to stop taking in the detected value, and the DC / DC conversion device 5 in the taking-in stop period uses the detected value just before the high voltage power supply 2 generates the voltage to the spark plug 1. It is controlled to do. That is, the control device 7 continues until the capacitive discharge current caused by the dielectric breakdown generated in the gap between the electrodes of the spark plug 1 is attenuated to a predetermined value after the high voltage power supply 2 generates the voltage in the spark plug 1. In the period (1), the power conversion operation of the DC / DC conversion device 5 is controlled using the detection value of the voltage detection means 55 immediately before the high voltage power supply 2 causes the spark plug 1 to generate a voltage.

As a result, the power conversion operation of the DC / DC conversion device 5 is not performed based on the detection value of the voltage detection means 55 when the detection error due to voltage oscillation is large, so the DC / DC conversion device caused by the detection error Erroneous output of 5 can be prevented.

At timing t5 after a predetermined delay time td1 has elapsed from timing t4, the control device 7 switches the voltage detection value capture stop signal shown in "g" of FIG. The conversion control circuit 56 controls to stop the acquisition of the detection value of the voltage detection means 55. This stage is step S107. The DC / DC conversion control circuit 56 holds the detected value at the timing t5, and based on the detected value at the timing t5 in a period until the timing t6 when the take-in stop signal of the voltage detected value becomes the low level Lo. The operation of the DC / DC converter 5 is controlled.

After the control device 7 controls the DC / DC conversion control circuit 56 to stop taking in the detection value of the voltage detection means 55 as described above, the DC / AC conversion control circuit 49 shown in "d" of FIG. The DC / AC conversion operation period signal is output at high level Hi. The DC / AC conversion control circuit 49 converts the energy charged in the power supply capacitor 54 into AC power by the DC / AC converter 4, and supplies the AC power to the spark plug 1. This stage is step S108 in FIG. As a result, high frequency plasma is generated in the spark plug 1. Here, the delay time td1 is, for example, about 50 [μs]. The shorter the delay time td1, the lower the discharge maintaining voltage of the spark plug 1 becomes.

The high frequency AC power supply 3 supplies AC power to the spark plug 1 for a time tac1 required for ignition. That is, at timing t6 when only the time tac1 necessary for ignition has elapsed from timing t5, the control device 7 sets the DC / AC conversion operation period signal indicated by "d" to the low level Lo. Thereby, the DC / AC conversion control circuit 49 stops the power conversion operation of the DC / AC conversion device 4. This stage is step S109. As a result, the high frequency plasma generated in the spark plug 1 disappears.

After stopping the power conversion operation of the DC / AC conversion device 4, the control device 7 switches the take-off stop signal of the voltage detection value shown in “g” of FIG. Control to start the acquisition of the detection value of the voltage detection means 55. This stage is step S110. As a result, the DC / DC conversion control circuit 56 controls the operation of the DC / DC conversion device 5 based on the detection value of the voltage detection means 55.

A part of the AC power output from the high frequency AC power supply 3 flows into the high frequency AC power supply 3 through the common ground level portion GND of the internal combustion engine. Since the alternating current has a high frequency on the order of MHz, when flowing into the reference potential of the high frequency alternating current power supply 3, voltage oscillation is caused to the reference potential of the high frequency alternating current power supply 3 by parasitic inductance such as wiring. Such voltage oscillation of the reference potential is superimposed on the voltage value of each part, and therefore is superimposed on the signal of the sensor or the like to cause an error in the detected value.

When voltage oscillation is superimposed on the detection value of the voltage detection means 55, the control device 7 may take in the minimum value of the oscillation detection value and detect the charging voltage V2 of the power supply capacitor 54 smaller than it actually is. is there. As a result, the DC / DC conversion device 5 supplies a power larger than necessary to the power supply capacitor 54, so the charging voltage V2 of the power supply capacitor 54 becomes larger than the voltage command value Vb. When the charging voltage V2 of the power supply capacitor 54 becomes larger than the originally intended voltage command value Vb, the switching loss of the semiconductor of the DC / AC conversion device 4 and the like increase and the power loss increases.

However, in the ignition device according to the third embodiment of the present invention, the DC / DC conversion control circuit 56 takes in the detection value of the voltage detection means 55 in a period in which AC power is superimposed on the detection value of the voltage detection means 55. The DC / DC conversion device 5 is controlled so as to stop the power supply during the intake stop period so that the power conversion operation is performed using the detection value immediately before the high frequency AC power supply 3 outputs the AC power to the spark plug 1. It is controlled.

That is, the control device 7 uses the detection value of the voltage detection means 55 immediately before the high frequency AC power supply 3 outputs the AC power to the spark plug 1 in the period when the high frequency AC power supply 3 outputs the AC power to the spark plug 1. , Control the power conversion operation of the DC / DC converter 5. As a result, the power conversion operation of the DC / DC conversion device 5 is not performed based on the detection value of the voltage detection means 55 when the detection error due to voltage oscillation is large, so the DC / DC conversion device caused by the detection error Erroneous output of 5 can be prevented.

The ignition device according to the third embodiment of the present invention repeats the above-described sequence operation for each ignition cycle Ti of the internal combustion engine. A typical ignition cycle Ti is about 10 ms to 100 ms.

The ignition device according to each of the embodiments of the present invention described above embodies one of the inventions of the following (1) to (16).
(1) A spark plug including a first electrode and a second electrode opposed to each other through a gap and igniting fuel in a combustion chamber of an internal combustion engine;
A high voltage power supply that applies a voltage to the spark plug to cause dielectric breakdown in the gap;
A high frequency alternating current power supply for applying a high frequency voltage to the spark plug to generate high frequency plasma in the gap;
A DC power supply for supplying power to the high voltage power supply and the high frequency AC power supply;
A control device that controls the operation of the high voltage power supply and the high frequency alternating current power supply;
An igniter having
The high frequency alternating current power supply is
A DC / AC conversion device which converts DC power into AC power of a predetermined frequency and outputs the converted AC power to the spark plug;
A DC / DC conversion device that converts DC power from a DC power supply into DC power having a predetermined voltage value and outputs the converted DC power to the DC / AC conversion device;
Equipped with
The controller is
In a period satisfying at least one of a period in which the capacity discharge current generated by the dielectric breakdown is smaller than a predetermined value, and a period in which the DC / AC conversion device does not output the AC power to the spark plug. The DC / DC conversion device is configured to perform a power conversion operation,
An ignition device characterized by
According to the present invention, in a period in which the DC / DC conversion device performs the power conversion operation, the capacitance discharge current due to dielectric breakdown and the alternating current output from the DC / AC conversion device simultaneously become the reference potential of the DC / DC conversion device. Inflow can be prevented, and detection errors of the voltage detection means can be suppressed. As a result, it is possible to prevent the DC / DC conversion device from outputting an unnecessarily large power due to the influence of the detection error, and to prevent an increase in power loss.
The present invention is embodied by the first embodiment.

(2) The control device
The DC / DC conversion device performs a power conversion operation in a period in which the capacity discharge current is smaller than a predetermined value and in a period in which the DC / AC conversion device does not output AC power to the spark plug. Control,
The igniter as described in said (1) characterized by the above-mentioned.
According to the present invention, in a period in which the DC / DC conversion device performs the power conversion operation, both of the capacitive discharge current due to dielectric breakdown and the output current of the DC / AC conversion device flow into the reference potential of the DC / DC conversion device To prevent the detection error of the voltage detection means. As a result, it is possible to prevent the DC / DC conversion device from outputting an unnecessarily large power due to the influence of the detection error, and to prevent an increase in power loss.
The present invention is embodied by the first embodiment.

(3) A spark plug including a first electrode and a second electrode opposed to each other through a gap and igniting fuel in a combustion chamber of an internal combustion engine;
A high voltage power supply that applies a voltage to the spark plug to cause dielectric breakdown in the gap;
A high frequency alternating current power supply for applying a high frequency voltage to the spark plug to generate high frequency plasma in the gap;
A DC power supply for supplying power to the high voltage power supply and the high frequency AC power supply;
A control device that controls the operation of the high voltage power supply and the high frequency alternating current power supply;
An igniter having
The high frequency alternating current power supply is
A DC / AC conversion device which converts DC power into AC power having a predetermined frequency and outputs the converted AC power to the spark plug;
A DC / DC conversion device that converts DC power from a DC power supply into DC power having a predetermined voltage value and outputs the converted DC power to the DC / AC conversion device;
Equipped with
The DC / DC conversion device
A power supply capacitor for charging energy of the converted DC power;
Voltage detection means for detecting the charging voltage of the power supply capacitor;
Equipped with
The controller is
After the high voltage power supply applies a voltage to the spark plug, the high voltage power supply supplies a voltage to the spark plug in a period until the capacitive discharge current generated by the dielectric breakdown becomes smaller than a predetermined value. It is configured to control a power conversion operation of the DC / DC conversion device using a detection value of the voltage detection means immediately before applying.
An ignition device characterized by
Since the DC / DC conversion device performs the power conversion operation using the detection value before the voltage oscillation is superimposed in the period in which the voltage oscillation is superimposed on the detection value of the voltage detection means, the present invention Thus, the DC / DC converter can be prevented from outputting an unnecessarily large amount of power due to the influence of the above, and an increase in power loss can be prevented.
The present invention is embodied by the third embodiment.

(4) A spark plug including a first electrode and a second electrode opposed to each other through a gap and igniting fuel in a combustion chamber of an internal combustion engine;
A high voltage power supply that applies a voltage to the spark plug to cause dielectric breakdown in the gap;
A high frequency alternating current power supply for applying a high frequency voltage to the spark plug to generate high frequency plasma in the gap;
A DC power supply for supplying power to the high voltage power supply and the high frequency AC power supply;
A control device that controls the operation of the high voltage power supply and the high frequency alternating current power supply;
An igniter having
The high frequency alternating current power supply is
A DC / AC conversion device which converts DC power into AC power having a predetermined frequency and outputs the converted AC power to the spark plug;
A DC / DC conversion device that converts DC power from a DC power supply into DC power having a predetermined voltage value and outputs the converted DC power to the DC / AC conversion device;
Equipped with
The DC / DC conversion device
A power supply capacitor for charging energy of the converted DC power;
Voltage detection means for detecting the charging voltage of the power supply capacitor;
Equipped with
The controller is
In a period in which the DC / AC converter outputs a current to the spark plug, the DC / DC conversion is performed using a detection value of the voltage detection unit immediately before the DC / AC converter outputs a current to the spark plug. Configured to control the power conversion operation of the device,
An ignition device characterized by
According to the present invention, in the period in which the voltage oscillation is superimposed on the detection value of the voltage detection means, the voltage oscillation causes the DC / DC conversion device to perform the power conversion operation using the detection value before the voltage oscillation is superimposed. The influence of the detection error can prevent the DC / DC conversion device from outputting an unnecessarily large amount of power, and can prevent an increase in power loss.
The present invention is embodied by the third embodiment.

(5) The control device
The DC / AC conversion device is controlled to perform a power conversion operation in a period in which the capacitive discharge current is smaller than a predetermined value and a period in which the DC / DC conversion device stops the power conversion operation.
The igniter as described in said (1) or (2) characterized by the above-mentioned.
According to the present invention, it is possible to prevent the capacitive discharge current from being superimposed on the output current of the DC / AC conversion device 4 and to control the output current of the DC / AC conversion device 4 using the detection value I1 of the current detection means 48 It becomes. In addition, in the power conversion operation of the DC / DC conversion device 5, the output current of the DC / AC conversion device 4 is prevented from flowing into the reference potential of the DC / DC conversion device 5, and the detection error in the voltage detection means 55 Can be suppressed. If the detection error is suppressed, the DC / DC conversion device 5 will not supply excessive or excessive power to the power supply capacitor 54, so that deterioration of the spark plug 1 and ignition failure can be prevented. As a result, an increase in the power loss of the high frequency AC power supply 3 is prevented, and the deterioration of the spark plug 1 and the deterioration of the ignition performance are prevented.
The present invention is embodied by the first embodiment.

(6) The control device
The high voltage power supply applies a voltage to the spark plug in a period in which the DC / DC conversion device does not perform a power conversion operation and in a period in which the DC / AC conversion device does not output AC power to the spark plug. Control to generate the dielectric breakdown,
An ignition device according to any one of the above (1), (2) and (6), characterized in that
According to the present invention, during the power conversion operation of the DC / DC conversion device 5, a part of the capacitive discharge current is prevented from flowing into the reference potential of the DC / DC conversion device 5, and the detection error of the voltage detection means 55 is It can be suppressed. In addition, it is possible to prevent the capacitive discharge current from being superimposed on the output current of the DC / AC conversion device 4 and to control the output current of the DC / AC conversion device 4 using the detection value I1 of the current detection means 48. Therefore, while preventing the increase in the power loss of high frequency alternating current power supply 3, it contributes to the prevention of degradation of ignition plug 1 and ignition performance fall.
The present invention is embodied by the first embodiment.

(7) The control device
It is configured to control operations of the high voltage power supply, the DC / DC conversion device, and the DC / AC conversion device based on an ignition command signal instructing a timing of firing the fuel.
An ignition device according to any one of the above (1) to (6), characterized in that
According to the present invention, the ignition command signal is controlled to ignite at a timing suitable for the environment and operating conditions of the internal combustion engine, and therefore, ignition can be easily performed at the optimum timing by operating the ignition device according to the ignition command signal. can do.
The present invention is embodied by the first embodiment.

(8) The control device
It is configured to control the operation of the high voltage power supply, the DC / DC conversion device, and the DC / AC conversion device based on an ignition command signal instructing a timing to ignite the fuel, and based on the ignition command signal The high voltage power supply is operated to apply a voltage to the spark plug after the DC / DC conversion device stops the power conversion operation.
An ignition device according to any one of the above (1), (2) and (5) to (7), characterized in that
The present invention is a specific operation when the DC / DC conversion apparatus is stopped and voltage generation by the high voltage power supply is performed based on the ignition command signal, and the above (1), (2), (5) It is an effective control means in order to acquire the effect of the invention as described in to (7).
The present invention is embodied by the first embodiment.

(9) The DC / AC conversion device
A current detection unit that detects an output current of the DC / AC conversion device and a capacitive discharge current generated by the dielectric breakdown;
The controller is
The power conversion operation of the DC / AC conversion device is controlled based on the detection value of the current detection means.
An ignition device according to any one of the above (1) to (8), characterized in that
According to the present invention, the detection method of the capacitive discharge current and the output current of the DC / AC converter accompanying the dielectric breakdown, and the specific operation of the power conversion of the DC / AC converter, are the above (1) to (8). The control means is effective to obtain the effects of the invention described in the above.
The present invention is embodied by the first embodiment.

(10) The control device
After detecting the generation of the capacitive discharge current, the DC / AC conversion device performs the power conversion operation after detecting that the peak value for each cycle of the capacitive discharge current is less than a predetermined value. To control,
The igniter as described in said (9) characterized by the above-mentioned.
According to the present invention, the output operation of AC power by the DC / AC conversion device is specifically described after the capacitance discharge current after dielectric breakdown detects attenuation, and the invention according to (9) above. It is an effective control means to obtain an effect.
The present invention is embodied by the first embodiment.

(11) The control device
The DC / AC conversion device is controlled to perform a power conversion operation after a predetermined time has elapsed from the timing when the high voltage power supply performs an operation for outputting a voltage to the spark plug.
An ignition device according to any one of the above (1) to (10), characterized in that
According to the present invention, the operation of outputting AC power by the DC / AC conversion device is specifically described after the capacity discharge current after the dielectric breakdown is attenuated, and is described in the above (1) to (10). The control means is effective to obtain the effects of the invention.
The present invention is embodied by the first embodiment.

(12) The control device
After stopping the power conversion operation of the DC / AC conversion device, permitting the power conversion operation of the DC / DC conversion device;
An ignition device according to any one of the above (1), (2) and (5) to (11), characterized in that
According to the present invention, the specific timing of the operation stop of the DC / AC conversion device and the operation permission of the DC / DC conversion device is described, and the above (1), (2), (5) to (11) It is an effective control method in order to acquire the effect of the invention described in 6.).
The present invention is embodied by the first embodiment.

(13) The control device
The DC / AC conversion device is configured to control operations of the high voltage power supply, the DC / DC conversion device, and the DC / AC conversion device based on an ignition command signal instructing a timing to ignite the fuel. The DC / DC conversion device is controlled to perform the power conversion operation in a period from the time when the power conversion operation of is stopped until the next ignition command signal is output,
An ignition device according to any one of the above (1), (2) and (5) to (12), characterized in that
According to the present invention, at the ignition timing, the charging voltage of the power supply capacitor is maintained at the output voltage command value, so that the applied voltage of the spark plug in the AC power output is maintained at the discharge maintenance voltage or more. It is possible to prevent the decrease in the ignition performance due to the inability to occur.
The present invention is embodied by the first embodiment.

(14) The control device
The operation of the high voltage power supply, the DC / DC conversion device, and the DC / AC conversion device is controlled based on an ignition command signal instructing a timing of ignition of the fuel, and the ignition command signal is output After the DC / AC conversion device stops the power conversion operation and provides a predetermined rest period in a single ignition period from when it is output to when the next ignition command signal is output, the DC / AC converter is again Control the AC converter to perform power conversion operation,
An ignition device according to any one of the above (1) to (13), characterized in that
According to the present invention, high-frequency plasma can be generated at a later timing from breakdown with less power consumption than when AC power is continuously output without providing a pause period. Can be prevented from becoming larger.
The present invention is embodied by the second embodiment.

(15) The control device is
The ignition device according to (14), wherein the DC / DC conversion device is controlled to perform a power conversion operation during the idle period.
According to the present invention, it is not necessary to cover all the power consumption in one ignition cycle of the DC / AC conversion device with only the energy pre-charged in the power supply capacitor, so that the capacity of the power supply capacitor can be increased. It can prevent the accompanying upsizing.
The present invention is embodied by the second embodiment.

(16) The control device
The DC / AC conversion device performs the power conversion operation in the one ignition period, and controls so as to provide the AC power output period for supplying the AC power to the spark plug a plurality of times each and the rest period. The igniter as described in said (14) or (15) characterized by the above-mentioned.
According to the present invention, the DC / AC conversion device can output AC power to the spark plug for a long time without increasing the capacity of the power supply capacitor, which contributes to the improvement of the ignition performance.
The present invention is embodied by the second embodiment.

The present invention is not limited to the ignition device according to the above-described first to third embodiments, and the configurations of the first, second, and second embodiments may be combined as appropriate without departing from the spirit of the present invention, It is possible to partially modify the configuration or partially omit the configuration.

The invention can be used in the field of ignition devices of internal combustion engines and thus in the field of the automotive industry.

DESCRIPTION OF SYMBOLS 1 spark plug, 1a 1st electrode, 1b 2nd electrode, 2 high voltage power supply, 3 high frequency alternating current power supply, 4 DC / AC conversion apparatus, 5 DC / DC conversion apparatus, 6 direct current power supply, 7 control apparatus, 10 ignition Device, 21 transformer, 21a transformer primary winding, 21b transformer secondary winding, 22 semiconductor switch, 23 diode, 41, 42, 43, 44 semiconductor switch, 45 step-up transformer, 45a step-up transformer primary winding , 45b step-up transformer secondary winding, 46 resonant inductor, 47 resonant capacitor, 48 current detection means, 49 DC / AC conversion control circuit, 50 boost chopper circuit, 51 inductor, 52 diode, 53 semiconductor switch, 54 for power supply Capacitor, 55 voltage detection means, 56 DC / DC conversion control circuit , GND ground level site

Claims

An ignition plug including a first electrode and a second electrode facing each other through a gap, for igniting fuel in a combustion chamber of an internal combustion engine;
A high voltage power supply that applies a voltage to the spark plug to cause dielectric breakdown in the gap;
A high frequency alternating current power supply for applying a high frequency voltage to the spark plug to generate high frequency plasma in the gap;
A DC power supply for supplying power to the high voltage power supply and the high frequency AC power supply;
A control device that controls the operation of the high voltage power supply and the high frequency alternating current power supply;
An igniter having
The high frequency alternating current power supply is
A DC / AC conversion device which converts DC power into AC power of a predetermined frequency and outputs the converted AC power to the spark plug;
A DC / DC conversion device that converts DC power from a DC power supply into DC power having a predetermined voltage value and outputs the converted DC power to the DC / AC conversion device;
Equipped with
The controller is
In a period satisfying at least one of a period in which the capacity discharge current generated by the dielectric breakdown is smaller than a predetermined value, and a period in which the DC / AC conversion device does not output the AC power to the spark plug. The DC / DC conversion device is configured to perform a power conversion operation,
An ignition device characterized by
The controller is
The DC / DC conversion device performs a power conversion operation in a period in which the capacity discharge current is smaller than a predetermined value and in a period in which the DC / AC conversion device does not output AC power to the spark plug. Control,
The igniter as claimed in claim 1,
An ignition plug including a first electrode and a second electrode facing each other through a gap, for igniting fuel in a combustion chamber of an internal combustion engine;
A high voltage power supply that applies a voltage to the spark plug to cause dielectric breakdown in the gap;
A high frequency alternating current power supply for applying a high frequency voltage to the spark plug to generate high frequency plasma in the gap;
A DC power supply for supplying power to the high voltage power supply and the high frequency AC power supply;
A control device that controls the operation of the high voltage power supply and the high frequency alternating current power supply;
An igniter having
The high frequency alternating current power supply is
A DC / AC conversion device which converts DC power into AC power having a predetermined frequency and outputs the converted AC power to the spark plug;
A DC / DC conversion device that converts DC power from a DC power supply into DC power having a predetermined voltage value and outputs the converted DC power to the DC / AC conversion device;
Equipped with
The DC / DC conversion device
A power supply capacitor for charging energy of the converted DC power;
Voltage detection means for detecting the charging voltage of the power supply capacitor;
Equipped with
The controller is
After the high voltage power supply applies a voltage to the spark plug, the high voltage power supply supplies a voltage to the spark plug in a period until the capacitive discharge current generated by the dielectric breakdown becomes smaller than a predetermined value. It is configured to control a power conversion operation of the DC / DC conversion device using a detection value of the voltage detection means immediately before applying.
An ignition device characterized by
An ignition plug including a first electrode and a second electrode facing each other through a gap, for igniting fuel in a combustion chamber of an internal combustion engine;
A high voltage power supply that applies a voltage to the spark plug to cause dielectric breakdown in the gap;
A high frequency alternating current power supply for applying a high frequency voltage to the spark plug to generate high frequency plasma in the gap;
A DC power supply for supplying power to the high voltage power supply and the high frequency AC power supply;
A control device that controls the operation of the high voltage power supply and the high frequency alternating current power supply;
An igniter having
The high frequency alternating current power supply is
A DC / AC conversion device which converts DC power into AC power having a predetermined frequency and outputs the converted AC power to the spark plug;
A DC / DC conversion device that converts DC power from a DC power supply into DC power having a predetermined voltage value and outputs the converted DC power to the DC / AC conversion device;
Equipped with
The DC / DC conversion device
A power supply capacitor for charging energy of the converted DC power;
Voltage detection means for detecting the charging voltage of the power supply capacitor;
Equipped with
The controller is
In a period in which the DC / AC converter outputs a current to the spark plug, the DC / DC conversion is performed using a detection value of the voltage detection unit immediately before the DC / AC converter outputs a current to the spark plug. Configured to control the power conversion operation of the device,
An ignition device characterized by
The controller is
The DC / AC conversion device is controlled to perform a power conversion operation in a period in which the capacitive discharge current is smaller than a predetermined value and a period in which the DC / DC conversion device stops the power conversion operation.
The igniter according to claim 1 or 2, characterized in that:
The controller is
The high voltage power supply applies a voltage to the spark plug in a period in which the DC / DC conversion device does not perform a power conversion operation and in a period in which the DC / AC conversion device does not output AC power to the spark plug. Control to generate the dielectric breakdown,
The ignition device according to any one of claims 1, 2, and 5, characterized in that.
The controller is
It is configured to control operations of the high voltage power supply, the DC / DC conversion device, and the DC / AC conversion device based on an ignition command signal instructing a timing of firing the fuel.
The ignition device according to any one of claims 1 to 6, characterized in that.
The controller is
It is configured to control the operation of the high voltage power supply, the DC / DC conversion device, and the DC / AC conversion device based on an ignition command signal instructing a timing to ignite the fuel, and based on the ignition command signal The high voltage power supply is operated to apply a voltage to the spark plug after the DC / DC conversion device stops the power conversion operation.
The ignition device according to any one of claims 1, 2, 5 to 7, characterized in that.
The DC / AC conversion device
A current detection unit that detects an output current of the DC / AC conversion device and a capacitive discharge current generated by the dielectric breakdown;
The controller is
The power conversion operation of the DC / AC conversion device is controlled based on the detection value of the current detection means.
9. An igniter as claimed in any one of the preceding claims, characterized in that.
The controller is
After detecting the generation of the capacitive discharge current, the DC / AC conversion device performs the power conversion operation after detecting that the peak value for each cycle of the capacitive discharge current is less than a predetermined value. To control,
The ignition device according to claim 9, characterized in that.
The controller is
The DC / AC conversion device is controlled to perform a power conversion operation after a predetermined time has elapsed from the timing when the high voltage power supply performs an operation for outputting a voltage to the spark plug.
The ignition device according to any one of claims 1 to 10, characterized in that.
The controller is
After stopping the power conversion operation of the DC / AC conversion device, permitting the power conversion operation of the DC / DC conversion device;
The igniter according to any one of claims 1, 2, 5 to 11, characterized in that.
The controller is
The DC / AC conversion device is configured to control operations of the high voltage power supply, the DC / DC conversion device, and the DC / AC conversion device based on an ignition command signal instructing a timing to ignite the fuel. The DC / DC conversion device is controlled to perform the power conversion operation in a period from the time when the power conversion operation of is stopped until the next ignition command signal is output,
The igniter as claimed in any one of claims 1, 2, 5 to 12, characterized in that.
The controller is
The operation of the high voltage power supply, the DC / DC conversion device, and the DC / AC conversion device is controlled based on an ignition command signal instructing a timing of ignition of the fuel, and the ignition command signal is output After the DC / AC conversion device stops the power conversion operation and provides a predetermined rest period in a single ignition period from when it is output to when the next ignition command signal is output, the DC / AC converter is again Control the AC converter to perform power conversion operation,
The igniter according to any one of claims 1 to 13, characterized in that.
The controller is
The ignition device according to claim 14, wherein the DC / DC conversion device is controlled to perform a power conversion operation during the idle period.
The controller is
The DC / AC conversion device performs the power conversion operation in the one ignition period, and controls so as to provide the AC power output period for supplying the AC power to the spark plug a plurality of times each and the rest period. The igniter as claimed in claim 14 or 15, characterized in that: