JP6264166B2 - Ignition device failure diagnosis device and ignition device failure diagnosis method - Google Patents

Description

  The present invention mainly relates to a failure diagnosis device for an ignition device used in an internal combustion engine (engine).

The following energy input circuit has been devised as a technique for reducing the burden on the spark plug, suppressing unnecessary power consumption, and continuing the spark discharge (for details, see Japanese Patent Application No. 2013-082958. This technique is not known). ). The energy input circuit supplies electric energy from the negative side of the primary coil before the spark discharge (hereinafter referred to as main ignition) started by a so-called full-trait ignition circuit disappears, and the secondary in the same direction as the main ignition. By causing the current to flow continuously, the spark discharge generated as the main ignition is continued for an arbitrary period.
Hereinafter, the spark discharge that is continued by the energy input circuit, that is, the spark discharge following the main ignition is referred to as a continuous spark discharge. Further, a period in which the continuous spark discharge continues is called a discharge continuation period.

The energy input circuit controls the primary current during the discharge duration to adjust the secondary current and maintain the spark discharge. In addition, by adjusting the secondary current during the continuous spark discharge, it is possible to reduce the burden on the spark plug, suppress unnecessary power consumption, and continue the spark discharge.
Next, for the purpose of assisting understanding of the present invention, a reference example of an energy input circuit to which the present invention is not applied will be described with reference to FIG.
The ignition device 100 shown in FIG. 6 includes a main ignition circuit 102 that causes a spark plug 101 to generate main ignition based on a full tiger, and an energy input circuit 103 that continues the main ignition to generate continuous spark discharge.

  When the switching element 104 is turned on, the main ignition circuit 102 causes a positive primary current to flow from the in-vehicle battery 105 to the primary coil 106 to store magnetic energy, and when the switching element 104 is turned off, the magnetic energy is generated by electromagnetic induction. Is converted into electric energy to generate a high voltage in the secondary coil 107 to cause main ignition. The energy input circuit 103 boosts the voltage of the in-vehicle battery 105 in the booster circuit 108 and stores the boosted voltage in the capacitor 109, and the electrical energy stored in the capacitor 109 is transferred to the negative side of the primary coil 106 by turning on and off the switching element 110. throw into.

(Task)
The energy input circuit 103 is used when there is a possibility that so-called blow-off may occur, such as supercharging and lean combustion using gasoline as fuel, and when the possibility of occurrence of blow-out is low, the energy input circuit 103 It is preferable to ignite based on the full tractor of the main ignition circuit 102 without using 103. Therefore, when an ignition control system is constructed in response to this request, the ignition device 100 controls use / non-use of the energy input circuit 103 according to the operating state of the engine. After the predetermined operating conditions are established, the energy input circuit 103 is used.

  For this reason, when a failure or the like occurs in the ignition device 100 including the energy input circuit 103 and a failed part is replaced, continuous spark discharge is mainly performed after the first engine start after replacement until a predetermined operating condition is satisfied in the engine. It cannot be determined whether or not it has occurred normally after ignition. As a result, in the unlikely event that the replacement product is broken, the engine continues to run without noticing the abnormality of the replacement product, which may cause some other problem.

Therefore, it is preferable that it is possible to determine whether or not the continuous spark discharge normally occurs after a failure or the like occurs in the ignition device 100 including the energy input circuit 103 and the failed part is replaced.
For example, Patent Document 1 discloses a failure diagnosis tool that determines whether or not a component has failed via an OBD connector or the like. Using such a tool, it is determined whether or not continuous spark discharge occurs normally. It is desirable to be able to do so.

Japanese Patent No. 4001088

  The present invention has been made in view of the above problems, and an object of the present invention is to determine whether or not a continuous spark discharge is normally generated after replacement of a part due to a failure or the like in an ignition device for an internal combustion engine having an energy input circuit. It is to be able to judge whether.

According to the failure diagnosis device for an ignition device for an internal combustion engine of the present invention, the ignition device to be subjected to failure diagnosis includes the following main ignition circuit and energy input circuit.
The main ignition circuit performs energization control of the primary coil of the ignition coil to cause spark discharge in the spark plug. The energy input circuit performs energization control of the primary coil during the spark discharge started by the operation of the main ignition circuit, and continuously supplies a secondary current in the same direction to the secondary coil of the ignition coil. The spark discharge started by the operation of the ignition circuit is continued.

The failure diagnosis apparatus includes the following spark discharge forcing means and abnormality determination means.
When a predetermined command signal is input, the spark discharge forcing means operates the main ignition circuit and continuously operates the energy input circuit. Further, the abnormality determination means determines whether or not a spark discharge has occurred due to execution of the spark discharge forcing means and has continued for a predetermined period.

  Thereby, it is possible to determine whether or not the continuous spark discharge is normally generated when the engine is stopped or when not much time has elapsed after the engine is started. For this reason, in an ignition device for an internal combustion engine provided with an energy input circuit, it is possible to determine whether or not continuous spark discharge is normally generated after replacement of a part associated with a failure or the like.

It is a block diagram of an ignition device (Example). It is a time chart which shows operation | movement of an ignition device (Example). It is a flowchart which shows the diagnostic procedure by a failure diagnosis apparatus (Example). It is a time chart which shows operation | movement of the ignition device at the time of the diagnosis by a failure diagnosis apparatus (Example). (A) is a time chart of the secondary current at normal time, (b) is a time chart of the secondary current at the time of abnormal continuous spark discharge, and (c) is a time chart of the secondary current at the time of abnormal main ignition. (Example). It is a block diagram of an ignition device (reference example).

  Hereinafter, modes for carrying out the invention will be described using examples. In addition, an Example discloses a specific example, and it cannot be overemphasized that this invention is not limited to an Example.

[Configuration of Example]
With reference to FIGS. 1-5, the ignition device 1 used as the diagnostic object of the failure diagnosis apparatus A of an Example is demonstrated.
The ignition device 1 is mounted on a spark ignition engine for running a vehicle, and ignites an air-fuel mixture in a combustion chamber at a predetermined ignition timing. An example of the engine is a direct injection engine capable of lean burn using gasoline as fuel, and a swirl flow control means for generating a swirl flow of an air-fuel mixture such as a tumble flow or a swirl flow in a cylinder. Prepare. In an operating state where the gas flow rate in the cylinder is high and there is a possibility that the spark discharge is blown out, such as lean burn, the ignition device 1 is controlled to perform continuous spark discharge following the main ignition.

The ignition device 1 is a DI (direct ignition) type that uses an ignition coil 3 corresponding to each ignition plug 2 of each cylinder.
Further, the ignition device 1 controls the primary coil 5 of the ignition coil 3 based on signals such as an ignition signal IGt and a discharge continuation signal IGw given from an electronic control unit (hereinafter referred to as ECU 4) that forms the center of engine control. The energization control is performed, and the electric energy generated in the secondary coil 6 of the ignition coil 3 is controlled by energizing the primary coil 5 to control the spark discharge of the spark plug 2.

  Here, the ECU 4 is mounted on the vehicle from various sensors that detect the operating state and control state of the engine (warm-up state, engine rotational speed, engine load, presence / absence of lean combustion, degree of swirling flow, etc.). A signal is input. The ECU 4 also includes an input circuit that processes an input signal, a CPU that performs control processing and arithmetic processing related to engine control based on the input signal, and various types of data stored and held such as data and programs necessary for engine control. And an output circuit for outputting signals necessary for engine control based on the processing results of the memory and CPU. Then, the ECU 4 generates and outputs an ignition signal IGt and a discharge continuation signal IGw corresponding to engine parameters acquired from various sensors.

  The ignition device 1 of the embodiment includes a main ignition circuit 8 that generates main ignition based on a full tiger, an energy input circuit 9 that continues a spark discharge generated as main ignition as a continuous spark discharge by adding additional electric energy, and a secondary A feedback circuit 10 that detects current and feeds it back to the energy input circuit 9 and an abnormality determination unit 11 that performs abnormality determination of the ignition device 1 are configured.

  The main ignition circuit 8, the energy input circuit 9, the feedback circuit 10, and the abnormality determination unit 11 are accommodated in one case as an ignition circuit unit, and the ignition plug 2, the ignition coil 3, and the ignition circuit unit include the number of cylinders. The same number is provided for each cylinder.

The spark plug 2 has a well-known structure, and includes a center electrode connected to one end of the secondary coil 6 and a ground electrode grounded through an engine cylinder head or the like. The generated electrical energy causes a spark discharge between the center electrode and the ground electrode.
The ignition coil 3 includes a primary coil 5 and a secondary coil 6, and a current (secondary current) is supplied to the secondary coil 6 by electromagnetic induction in accordance with an increase or decrease of a current (primary current) flowing through the primary coil 5. It is a well-known structure that generates

  One end of the primary coil 5 is connected to the plus electrode of the on-vehicle battery 12, and the other end of the primary coil 5 is grounded via the ignition switching means 13 of the main ignition circuit 8. Further, an energy input circuit 9 is connected to the other end of the primary coil 5 in parallel with a line grounded via the ignition switching means 13.

  One end of the secondary coil 6 is connected to the center electrode of the spark plug 2 as described above, and the other end of the secondary coil 6 is connected to the feedback circuit 10. The other end of the secondary coil 6 is connected to the feedback circuit 10 via a first diode 14 that limits the direction of the secondary current to one direction.

  The main ignition circuit 8 causes the primary coil 5 to store energy when the ignition switching means 13 is turned on and off, and also uses the energy stored in the primary coil 5 to generate a high voltage in the secondary coil 6 for ignition. Main ignition is caused to the plug 2.

  More specifically, the main ignition circuit 8 includes ignition switching means 13 for intermittently energizing the primary coil 5. The main ignition circuit 8 turns on the ignition switching means 13 during a period in which the ignition signal IGt is given from the ECU 4, thereby applying a positive primary current by applying the voltage of the on-vehicle battery 12 to the primary coil 5. The magnetic energy is stored in the primary coil 5. Thereafter, when the ignition switching means 13 is turned off, the main ignition circuit 8 converts magnetic energy into electric energy by electromagnetic induction and generates a high voltage in the secondary coil 6 to cause main ignition.

  The ignition switching means 13 is a power transistor, a MOS transistor, a thyristor, or the like. Further, the ignition signal IGt is a signal for instructing a period during which the primary coil 5 stores magnetic energy in the main ignition circuit 8 and an ignition start timing.

The energy input circuit 9 includes the following booster circuit 15 and input energy control means 16.
First, the booster circuit 15 boosts the voltage of the in-vehicle battery 12 and stores it in the capacitor 18 during a period when the ignition signal IGt is given from the ECU 4.
Next, the input energy control means 16 inputs the electric energy stored in the capacitor 18 to the negative side (ground side) of the primary coil 5.

In addition to the capacitor 18, the booster circuit 15 includes a choke coil 19, a boosting switching unit 20, a booster driver circuit 21, and a second diode 22. Note that the boosting switching means 20 is, for example, a MOS transistor.
Here, one end of the choke coil 19 is connected to the plus electrode of the in-vehicle battery 12, and the energization state of the choke coil 19 is interrupted by the boosting switching means 20. Further, the boosting driver circuit 21 supplies a control signal to the boosting switching means 20 to turn on and off the boosting switching means 20, and the magnetic energy stored in the choke coil 19 by the on / off operation of the boosting switching means 20. Is charged as electrical energy by the capacitor 18.

Note that the boosting driver circuit 21 is provided so as to repeatedly turn on and off the boosting switching means 20 at a predetermined period during a period when the ignition signal IGt is given from the ECU 4.
The second diode 22 prevents the electrical energy stored in the capacitor 18 from flowing back to the choke coil 19 side.

The input energy control means 16 includes the following input switching means 24, input driver circuit 25, and third diode 26. The switching means 24 for making up is, for example, a MOS transistor.
Here, the input switching means 24 turns on / off the electric energy stored in the capacitor 18 from being input to the primary coil 5 from the minus side, and the input driver circuit 25 gives a control signal to the input switching means 24. To turn it on and off.

Then, the making driver circuit 25 controls the electric energy to be inputted from the capacitor 18 to the primary coil 5 by turning on and off the making switching means 24 so that the secondary current is predetermined during the period in which the discharge continuation signal IGw is given. Keep it at the value. Here, the discharge continuation signal IGw is a signal for instructing a period during which the continuous spark discharge is continued. More specifically, the on / off switching means 24 is repeatedly turned on and off to cause the primary coil 5 to be electrically connected to the booster circuit 15. This is a signal for instructing a period during which energy is input.
The third diode 26 prevents the backflow of current from the primary coil 5 to the capacitor 18.

The feedback circuit 10 detects the secondary current and feeds it back to the input energy control means 16 of the energy input circuit 9.
Here, the feedback circuit 10 is provided with a secondary current detection resistor 28 for detecting a secondary current and a current detection circuit 29 for synthesizing and outputting a feedback signal. The detected value of the secondary current is converted into a voltage by the secondary current detection resistor 28 and output to the current detection circuit 29. In the current detection circuit 29, for example, upper and lower thresholds for the secondary current are set, and a feedback signal corresponding to the comparison between the detected value and the upper and lower thresholds is synthesized to the input driver circuit 25. Is output.

  For example, in the current detection circuit 29, the abnormality determination unit 11 determines whether there is an abnormality based on the detection value of the secondary current when the detection value of the secondary current is out of the upper and lower limit range. When the determination is made, the diagnosis signal IGf is output to the ECU 4.

Next, the normal operation of the ignition device 1 will be described with reference to FIG.
In FIG. 2, “IGt” represents the input state of the ignition signal IGt as high / low, and “IGw” represents the input state of the discharge continuation signal IGw as high / low. “Ignition switch” and “turn-on switch” represent on / off of the ignition switching means 13 and the turn-on switching means 24, respectively, and “I1” is the primary current (current value flowing through the primary coil 5). , “I2” represents a secondary current (a current value flowing through the secondary coil 6).

  When the ignition signal IGt switches from low to high (see time t01), during the period when the ignition signal IGt is high, the ignition switching means 13 is maintained in an on state and a positive primary current flows, and the primary coil 5 Magnetic energy is stored in Further, the boosting switching means 20 repeatedly turns on and off to perform a boosting operation, and the boosted electrical energy is stored in the capacitor 18.

Eventually, when the ignition signal IGt switches from high to low (see time t02), the ignition switching means 13 is turned off and the energized state of the primary coil 5 is cut off. Thereby, the magnetic energy stored in the primary coil 5 is converted into electric energy, a high voltage is generated in the secondary coil 6, and main ignition is started in the spark plug 2.
After the main ignition is started in the spark plug 2, the secondary current attenuates in a substantially triangular wave shape (see the dotted line I2). Then, the discharge continuation signal IGw switches from low to high before the secondary current reaches the lower limit threshold (see time t03).

  When the discharge continuation signal IGw switches from low to high, the on / off switching means 24 is on / off controlled, and the electric energy stored in the capacitor 18 is sequentially input to the negative side of the primary coil 5 and the primary current is It flows from the primary coil 5 toward the plus electrode of the in-vehicle battery 12. More specifically, a primary current from the primary coil 5 toward the positive electrode of the in-vehicle battery 12 is added each time the input switching unit 24 is turned on, and the primary current increases to the negative side (time). (See t03 to t04.)

Each time the primary current is added, a secondary current in the same direction as the secondary current caused by the main ignition is sequentially added to the secondary coil 6, and the secondary current is maintained between the upper and lower limits.
As described above, by controlling the on / off switching means 24, the secondary current continuously flows to such an extent that the spark discharge can be maintained. As a result, if the ON state of the discharge continuation signal IGw continues, continuous spark discharge is maintained in the spark plug 2.

Next, the failure diagnosis apparatus A will be described.
The failure diagnosis device A determines whether or not the continuous spark discharge is normally generated after replacement of a part associated with a failure or the like in the ignition device 1. For example, the ECU 4, the abnormality determination unit 11, and diagnosis outside the vehicle It is formed by the tool 31 or the like. Here, the ECU 4 can connect the diagnostic tool 31 via a connector, and diagnoses the ignition device 1 according to various command signals output from the diagnostic tool 31. At this time, the abnormality determination unit 11 determines whether or not the continuous spark discharge is normally generated based on the detected value of the secondary current.

In diagnosis of the ignition device 1, the ECU 4 and the abnormality determination unit 11 function as the following spark discharge forcing unit and abnormality determination unit, respectively.
First, the spark discharge forcing means operates the main ignition circuit 8 and continuously operates the energy input circuit 9 when various command signals are input. The abnormality determination means determines whether or not a spark discharge has occurred due to execution of the spark discharge forcing means and has continued for a predetermined period.

Hereinafter, the control flow including the steps of the spark discharge forcing means and the abnormality determination means will be described with reference to FIGS.
In FIG. 4, “diagnosis request signal” represents the input state of the diagnosis request signal as high / low, and “DCDC drive request signal” represents the input state of the DCDC drive request signal as high / low. Yes, the “discharge execution request signal” represents the input state of the discharge execution request signal as high / low, “IGt” represents the input state of the ignition signal IGt as high / low, and “IGw” The input state of the discharge continuation signal IGw is represented by high / low. Further, “boost switch” represents ON / OFF of the boost switching means 20, and “I2” represents a secondary current (a current value flowing through the secondary coil 6).

The control flow in FIG. 3 is executed, for example, when the engine is stopped by connecting the diagnostic tool 31 to the ECU 4 and inputting various command signals from the diagnostic tool 31 to the ECU 4.
First, in step S1, the ECU 4 determines whether or not a diagnosis request signal for requesting diagnosis of the ignition device 1 is input from the diagnosis tool 31 (see time t1 in FIG. 4). If it is determined that a diagnosis request signal has been input (YES), the process proceeds to step S2, and if it is determined that a diagnosis request signal has not been input (NO), the control flow ends.

  Next, in step S2, the ECU 4 determines whether or not a DCDC drive request signal for instructing charging of the capacitor 18 is input from the diagnostic tool 31 (see time t2 in FIG. 4). If it is determined that the DCDC drive request signal has been input (YES), the process proceeds to step S3. If it is determined that the DCDC drive request signal has not been input (NO), the control flow ends.

  In step S3, on / off control for the boosting switching means 20 by the boosting driver circuit 21 is started (see time t2 in FIG. 4). Then, electric energy is accumulated in the capacitor 18 until the voltage value of the capacitor 18 (hereinafter sometimes referred to as Vdc voltage) exceeds a predetermined value.

  Next, in step S4, the ECU 4 determines whether or not the Vdc voltage is greater than or equal to a predetermined value. If it is determined that the Vdc voltage is equal to or higher than the predetermined value (YES), the process proceeds to step S5. If it is determined that the Vdc voltage is lower than the predetermined value (NO), the process waits until the Vdc voltage becomes equal to or higher than the predetermined value. . Next, in step S5, the ECU 4 determines whether or not a discharge execution request signal for requesting execution of spark discharge has been input from the diagnostic tool 31 (see time t3 in FIG. 4). If it is determined that a discharge execution request signal has been input (YES), the process proceeds to step S6. If it is determined that a discharge execution request signal has not been input (NO), the control flow is terminated.

In step S6, the ignition signal IGt and the discharge continuation signal IGw are output from the ECU 4, and the main ignition and the continuous spark discharge based on the ignition signal IGt and the discharge continuation signal IGw are started (see time t3 in FIG. 4). The ignition device 1 operates in the same manner as in FIG. 2 and generates a secondary current.
Thereafter, until the input of the discharge execution request signal stops (see time t4 in FIG. 4), the ignition signal IGt and the discharge continuation signal IGw are repeatedly output from the ECU 4, and the ignition device 1 performs the same operation as in FIG. A secondary current is repeatedly generated (steps S1 to S6 correspond to the spark discharge forcing means).

In step S6, each time main ignition and continuous spark discharge occur, it is determined whether or not spark discharge has occurred and continued for a predetermined period of time (that is, step S6 corresponds to an abnormality determination means).
This determination is performed by determining whether or not the continuous spark discharge has occurred normally by the abnormality determination unit 11.

Here, as shown in FIG. 5, the abnormality determination unit 11 has a function of determining whether the main ignition and the continuous spark discharge have occurred normally.
For example, the abnormality determination unit 11 performs the main ignition normally based on whether or not the detected value of the secondary current is larger than the predetermined threshold value α at a predetermined time ta counted from the ignition signal IGt being turned off. It is determined whether or not it has occurred. That is, the abnormality determination unit 11 determines that the main ignition has occurred normally when the detected value of the secondary current is larger than the threshold value α at the time ta.

Further, the abnormality determination unit 11 performs normal spark discharge normally based on whether or not the detected value of the secondary current is larger than the predetermined threshold β at a time tb later than the time ta. It is determined whether or not it has occurred. That is, the abnormality determination unit 11 determines that the continuous spark discharge has occurred normally when the detected value of the secondary current is larger than the threshold value β at the time tb.
The threshold value β is set as a value larger on the minus side than the threshold value α.

[Effects of Examples]
The failure diagnosis apparatus A according to the embodiment includes an ECU 4, an abnormality determination unit 11, and a diagnosis tool 31, and has functions of the following spark discharge forcing unit and abnormality determination unit.
First, the spark discharge forcing means operates the main ignition circuit 8 and continuously operates the energy input circuit 9 in response to input of various command signals. Further, the abnormality determination means determines whether or not a spark discharge has occurred due to execution of the spark discharge forcing means and has continued for a predetermined period.

  Thereby, even when the engine is stopped, it can be determined whether or not the continuous spark discharge is normally generated. For this reason, in the ignition device 1 provided with the energy input circuit 9, it is possible to determine in advance whether or not the continuous spark discharge is normally generated before starting the engine after the parts replacement due to failure or the like.

[Modification]
In the above-described embodiment, an example in which the ignition device 1 is diagnosed by inputting various command signals related to diagnosis from the diagnostic tool 31 to the ECU 4 is disclosed. The diagnosis may be performed without using the diagnostic tool 31.
In the above embodiment, the secondary current is controlled based on the upper and lower limits set by the current detection circuit 29 also at the time of failure diagnosis. However, at the time of failure diagnosis, a command value of the secondary current is separately input from the diagnostic tool 31, for example. Further, feedback control may be performed so that the detected value substantially coincides with the command value.

  In the above embodiment, the diagnosis related to the continuous spark discharge is mainly performed when the engine is stopped. However, the diagnosis related to the continuous spark discharge may be performed after the engine is started. In this case, failure determination of other components can be performed together.

  In the above embodiment, an example in which the ignition device 1 of the present invention is used for a gasoline engine has been shown. However, since continuous ignition can improve the ignitability of an air-fuel mixture, an engine using ethanol fuel or mixed fuel can be used. You may apply. Even if it is used for an engine in which poor fuel may be used, the ignitability can be improved by continuous spark discharge.

  In the above-described embodiment, an example in which the ignition device 1 of the present invention is used for an engine capable of lean burn operation has been shown. However, even in a combustion state different from lean combustion, ignitability is caused by continuous spark discharge. Since improvement can be achieved, the present invention is not limited to application to an engine capable of lean combustion, and may be used for an engine that does not perform lean combustion.

  In the above embodiment, an example in which the ignition device 1 of the present invention is used in a direct injection engine that directly injects fuel into the combustion chamber has been described. However, port injection that injects fuel to the intake upstream side (inside the intake port) of the intake valve. It may be used for a formula engine.

  In the above-described embodiment, an example in which the ignition device 1 of the present invention is used for an engine that positively generates a swirl flow (such as a tumble flow or a swirl flow) of an air-fuel mixture in a cylinder has been disclosed. You may use for the engine which does not have a tumble flow control valve, a swirl flow control valve, etc.).

  In the above embodiment, the present invention is applied to the DI type ignition device 1, but a distributor type that distributes the secondary voltage to each spark plug 2 or a single cylinder engine that does not require the distribution of the secondary voltage ( For example, the present invention may be applied to the ignition device 1 of a motorcycle.

DESCRIPTION OF SYMBOLS 1 Ignition device 2 Spark plug 3 Ignition coil 4 ECU (spark discharge forcing means) 5 Primary coil 6 Secondary coil 8 Main ignition circuit 9 Energy input circuit 11 Abnormality judgment part (abnormality judgment means) A Fault diagnosis device

Claims (4)

A failure diagnosis device (A) for an ignition device (1) for an internal combustion engine,
The ignition device (1) that is the target of failure diagnosis is
A main ignition circuit (8) for controlling the energization of the primary coil (5) of the ignition coil (3) to cause a spark discharge in the spark plug (2);
During the spark discharge started by the operation of the main ignition circuit (8), the energization control of the primary coil (5) is performed, and the secondary coil (6) of the ignition coil (3) is subjected to the secondary in the same direction. An energy input circuit (9) for continuously flowing a current and continuing a spark discharge started by the operation of the main ignition circuit (8);
The failure diagnosis device (A)
When a predetermined command signal is input, a spark discharge forcing means (4) for operating the main ignition circuit (8) and subsequently operating the energy input circuit (9);
A failure diagnosis device (A) comprising abnormality determination means (11) for determining whether or not a spark discharge has occurred by the execution of the spark discharge forcing means (4) and has continued for a predetermined period. In the fault diagnosis apparatus (A) according to claim 1,
The ignition device (1) to be subjected to the failure diagnosis is
A feedback circuit (10) for detecting the secondary current and feeding back to the energy input circuit (9);
The abnormality determination means (11) determines whether or not the secondary current has reached a desired value at a predetermined timing during a period in which the energy input circuit (9) is operating. It is determined whether it continued for a predetermined period, The fault diagnostic apparatus (A) characterized by the above-mentioned. A failure diagnosis method for an ignition device (1) for an internal combustion engine, comprising:
The ignition device (1) that is the target of failure diagnosis is
A main ignition circuit (8) for controlling the energization of the primary coil (5) of the ignition coil (3) to cause a spark discharge in the spark plug (2);
During the spark discharge started by the operation of the main ignition circuit (8), the energization control of the primary coil (5) is performed, and the secondary coil (6) of the ignition coil (3) is subjected to the secondary in the same direction. An energy input circuit (9) for continuously flowing a current and continuing a spark discharge started by the operation of the main ignition circuit (8);
The failure diagnosis method includes:
Even when the internal combustion engine is stopped, when a predetermined command signal is input, a spark discharge forcing step of operating the main ignition circuit (8) and subsequently operating the energy input circuit (9);
A failure diagnosis method comprising: an abnormality determination step for determining whether or not a spark discharge is generated by the spark discharge forcing step and continues for a predetermined period. The failure diagnosis method according to claim 3,
The ignition device (1) to be subjected to the failure diagnosis is
A feedback circuit (10) for detecting the secondary current and feeding back to the energy input circuit (9);
The abnormality determination step determines whether or not the secondary current has reached a desired value at a predetermined timing during a period in which the energy input circuit (9) is operating, so that the spark discharge is performed for a predetermined period. A failure diagnosis method characterized by determining whether or not the operation is continued.

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