JP5662891B2 - Spark discharge detection method and spark discharge detection device - Google Patents

Description

  The present invention relates to a spark discharge detection method and a spark discharge detection device for detecting a spark discharge of a spark plug used in an internal combustion engine or the like.

  The spark plug is attached to, for example, an internal combustion engine (engine) and used for igniting an air-fuel mixture in the combustion chamber. In general, a spark plug is composed of an insulator having a shaft hole, a center electrode inserted through the tip end of the shaft hole, a metal shell provided on the outer periphery of the insulator, and a ground connected to the tip of the metal shell. The spark discharge gap is formed between the ground electrode and the center electrode. When a high voltage is applied to the center electrode, a spark discharge is generated in the spark discharge gap, and the mixture is ignited.

  By the way, if the spark discharge gap has expanded due to wear of the center electrode or ground electrode due to the spark discharge, or if a high supercharge or high compression internal combustion engine is used, a high voltage is applied to the spark plug. Depending on the supply energy of the power supply device to which the voltage is applied, the potential difference between the center electrode and the ground electrode cannot exceed the dielectric breakdown voltage of the spark discharge gap, so that the spark discharge may not be performed normally. Therefore, in order to determine whether or not the spark discharge has occurred normally, whether or not the spark discharge has occurred by comparing a value (partial pressure value) based on the voltage applied to the spark plug with a predetermined threshold value. There has been proposed a technique for determining whether or not (see, for example, Patent Document 1).

JP 52-118135 A

  However, the difference between the spark plug voltage when a spark discharge occurs and the spark plug voltage when a spark discharge does not occur is not so large, and an erroneous determination occurs due to the influence of noise or the like. There is a risk that.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a spark discharge detection method and a spark discharge detection capable of accurately detecting whether or not a spark discharge has occurred normally in a spark plug. To provide an apparatus.

  Hereinafter, each configuration suitable for solving the above-described object will be described in terms of items. In addition, the effect specific to the corresponding structure is added as needed.

Configuration 1. The spark discharge detection method of this configuration includes an ignition plug and a voltage application unit that applies a voltage to the ignition plug, and a spark discharge is applied to the ignition plug by applying a voltage from the voltage application unit to the ignition plug. A spark discharge detection method for detecting spark discharge in the spark plug in the ignition device to be generated,
The peak value of the differential value of the voltage waveform corresponding to the voltage applied to the spark plug has a predetermined threshold for determination during a predetermined determination period from the time when the voltage is applied to the spark plug from the voltage application unit. When exceeded, it is determined that a spark discharge has occurred in the spark plug ,
The voltage application unit includes a primary coil to which a primary voltage is applied from a predetermined power supply device, and a secondary coil that generates a high voltage for spark discharge by stopping application of the primary voltage to the primary coil,
The determination threshold is set based on the primary voltage and the energization time of the primary voltage to the primary coil .

  The “determination period” is a period during which spark discharge can occur in the spark plug, and corresponds to a period during which voltage is applied from the voltage application unit to the spark plug. For example, by measuring the output voltage from the voltage application unit in the environment of the ignition coil (voltage application unit) measurement method defined in JIS D5121, the capability waveform of the voltage application unit can be measured. The time width of the waveform can be set as the determination period. The “determination threshold” is a waveform corresponding to the capability waveform of the voltage application unit (for example, a waveform based on the capability waveform of the voltage application unit obtained by a device that acquires an applied voltage to the spark plug from the voltage application unit. A numerical value (preferably a numerical value about 2 to 3 times the peak value) larger than the peak value of the differential value is set.

  When a spark discharge is normally generated in the spark plug, the voltage waveform corresponding to the voltage applied to the spark plug has a portion corresponding to a capacity discharge in which the voltage value changes rapidly and an induction in which a minute current flows after the capacity discharge. And a portion corresponding to discharge. On the other hand, when no spark discharge occurs in the spark plug, the voltage waveform corresponding to the voltage applied to the spark plug has substantially the same shape as the above-described capability waveform and does not include a portion where the voltage value changes rapidly. .

  In view of this point, according to the configuration 1, the peak value of the differential value of the voltage waveform (the amount of change in the voltage value in a minute time) is compared with a predetermined determination threshold, and the peak value is determined to be a predetermined value. When the determination threshold is exceeded, it is configured to determine that a spark discharge has occurred. That is, the presence or absence of spark discharge is detected based on the peak value of the differential value of the voltage waveform that causes a large difference between when spark discharge occurs and when spark discharge does not occur. Therefore, even if a slight fluctuation occurs in the voltage waveform due to the influence of noise or the like, it can be detected with high accuracy whether or not a spark discharge has occurred.

  Whether or not a misfire has occurred based on the differential value of the voltage when the voltage of the spark plug fluctuates due to factors such as changes in the combustion state due to lean or rich fuel. There has been proposed a technique for determining whether or not (see JP-A-5-164034). However, although this technology can detect misfire caused by the fuel system, it cannot detect misfire caused by the ignition system such as the spark plug and the voltage application unit, and accurately identifies the cause of the misfire. I can't do it. On the other hand, according to the above configuration 1, when it is detected that no spark discharge has occurred (when misfire is detected), the cause of the occurrence is caused by an ignition system such as a spark plug or a voltage application unit. To do. That is, according to the above-described configuration 1, whether or not the cause of misfire is caused by an ignition system such as a spark plug or by other factors by detecting whether or not a spark discharge has occurred. Can be easily identified.

Further, when the magnitude of the primary voltage and the energization time of the primary voltage are changed, the applied voltage (secondary voltage) to the spark plug can be increased or decreased. According to the configuration 1, the magnitude of the primary voltage and the primary voltage The determination threshold value is set based on the energization time. Therefore, a more appropriate determination threshold value corresponding to the voltage applied to the spark plug can be set. As a result, the detection accuracy of spark discharge can be further improved.

Configuration 2. The spark discharge detection method of this configuration includes an ignition plug and a voltage application unit that applies a voltage to the ignition plug, and a spark discharge is applied to the ignition plug by applying a voltage from the voltage application unit to the ignition plug. A spark discharge detection method for detecting spark discharge in the spark plug in the ignition device to be generated,
The differential value of the voltage waveform corresponding to the voltage applied to the spark plug from the time when the voltage is applied to the spark plug from the voltage application unit until the next time the voltage is applied to the spark plug. When the peak value held exceeds a predetermined threshold for determination , it is determined that a spark discharge has occurred in the spark plug ,
The voltage application unit includes a primary coil to which a primary voltage is applied from a predetermined power supply device, and a secondary coil that generates a high voltage for spark discharge by stopping application of the primary voltage to the primary coil,
The determination threshold is set based on the primary voltage and the energization time of the primary voltage to the primary coil .

  According to the said structure 2, the effect similar to the said structure 1 is show | played fundamentally.

  In addition, according to the above-described configuration 2, it is not necessary to acquire the value of the differential waveform at any time in order to obtain the peak value. For example, the held peak value is compared with the determination threshold after the determination period has elapsed. Thus, it is possible to detect whether or not a spark discharge has occurred. Therefore, it is possible to reduce the processing burden when detecting the spark discharge. Further, since the processing load is reduced, the detection process can be performed with sufficient accuracy even if the processing capability of the apparatus for performing the detection process is not so high.

Configuration 3. Spark discharge detection method of the present configuration, in Configuration 1, the front Symbol primary voltage, on the basis of the energization time of the primary voltage to the primary coil, and sets the determination period.

  Even if the required voltage fluctuates due to factors such as an increase in the spark discharge gap, voltage application is possible by changing the magnitude of the primary voltage and the energization time of the primary voltage in order to generate spark discharge as normally as possible. It is conceivable to increase the electrical energy supplied from the part to the spark plug. However, in such a case, the energization time from the voltage application unit to the spark plug (that is, the period during which spark discharge can occur) may vary.

  In view of this point, the configuration 3 is configured such that the determination period is set based on the magnitude of the primary voltage and the energization time of the primary voltage. Therefore, the peak value of the differential value during the period in which the spark discharge can occur can be obtained more reliably, and as a result, whether or not the spark discharge has occurred can be detected with higher accuracy.

Configuration 4 . The spark discharge detection method of this configuration is the predetermined number of times determined in any one of the above-described configurations 1 to 3 that a spark discharge is generated in the spark plug within a predetermined time. When it is less than the number of times, it is notified that an abnormality has occurred in at least one of the spark plug and the voltage application unit.

  If misfires frequently occur within a predetermined time, there is a high possibility that an abnormality has occurred in the spark plug or the voltage application unit, and there is a possibility that the output of the internal combustion engine or the like will be reduced or the fuel consumption will be deteriorated.

In this regard, according to the above-described configuration 4, when the number of detections of the spark discharge is less than the predetermined number within a predetermined time set in advance, it is notified that an abnormality has occurred in the spark plug and the voltage application unit. It is comprised so that. Therefore, the abnormal state can be quickly resolved by replacing the spark plug, and the situation where the output decrease and the fuel consumption deterioration continue for a long time can be more reliably prevented.

Configuration 5 . The spark discharge detection device of this configuration includes an ignition plug and a voltage application unit that applies a voltage to the ignition plug, and a spark discharge is applied to the ignition plug by applying a voltage from the voltage application unit to the ignition plug. In the ignition device to be generated, a spark discharge detection device for detecting a spark discharge in the spark plug,
The peak value of the differential value of the voltage waveform corresponding to the voltage applied to the spark plug has a predetermined threshold for determination during a predetermined determination period from the time when the voltage is applied to the spark plug from the voltage application unit. A discharge detector that determines that a spark discharge has occurred in the spark plug when exceeded ,
The voltage application unit includes a primary coil to which a primary voltage is applied from a predetermined power supply device, and a secondary coil that generates a high voltage for spark discharge by stopping application of the primary voltage to the primary coil,
And the primary voltage, on the basis of the energization time of the primary voltage to the primary coil, and wherein Rukoto to have a threshold value setting unit capable of setting the determination threshold value.

  According to the said structure 5, the effect similar to the said structure 1 is show | played.

Configuration 6 . The spark discharge detection device of this configuration includes an ignition plug and a voltage application unit that applies a voltage to the ignition plug, and a spark discharge is applied to the ignition plug by applying a voltage from the voltage application unit to the ignition plug. In the ignition device to be generated, a spark discharge detection device for detecting a spark discharge in the spark plug,
The differential value of the voltage waveform corresponding to the voltage applied to the spark plug from the time when the voltage is applied to the spark plug from the voltage application unit until the next time the voltage is applied to the spark plug. A peak hold section for holding the peak value of
A discharge detection unit that determines that a spark discharge has occurred in the spark plug when a peak value held by the peak hold unit exceeds a predetermined determination threshold ;
The voltage application unit includes a primary coil to which a primary voltage is applied from a predetermined power supply device, and a secondary coil that generates a high voltage for spark discharge by stopping application of the primary voltage to the primary coil,
And the primary voltage, on the basis of the energization time of the primary voltage to the primary coil, and wherein Rukoto to have a threshold value setting unit capable of setting the determination threshold value.

According to the said structure 6 , the effect similar to the said structure 2 will be show | played.

Configuration 7 . Spark discharge detection device of the present configuration, characterized by having the above structure 5, the front Symbol primary voltage, on the basis of the energization time of the primary voltage to the primary coil, the determination period setting unit capable of setting the determination period And

According to the said structure 7 , the effect similar to the said structure 3 will be show | played.

Configuration 8 . The spark discharge detection device of this configuration is the predetermined number of times in which the number of times it is determined that a spark discharge has occurred in the spark plug within a predetermined time set in advance in any one of the above configurations 5 to 7. When it is less than the number of times, it is characterized by comprising a notifying unit for notifying that at least one of the spark plug and the voltage applying unit is abnormal.

According to the said structure 8 , the effect similar to the said structure 4 will be show | played.

It is a block diagram which shows schematic structure of an ignition device. It is a partially broken front view which shows the structure of a spark plug. (A) shows the voltage waveform of the spark plug when the required voltage is relatively low, and (b) shows the differential waveform when the required voltage is relatively low. (A) shows the voltage waveform of the spark plug when the required voltage is relatively high, and (b) shows the differential waveform when the required voltage is relatively high. (A) shows the voltage waveform of the spark plug when no spark discharge occurs, and (b) shows the differential waveform when no spark discharge occurs. It is a map showing the relationship between a primary voltage and its energization time, and a threshold reference value. It is a flowchart which shows the main routine of the process performed in a spark discharge detection apparatus. It is a flowchart which shows an interruption process. It is a flowchart which shows a spark discharge determination process. It is a block diagram which shows schematic structure of the ignition device in 2nd Embodiment. (A) shows the differential waveform when spark discharge occurs in the spark plug, and (b) shows the output from the peak hold unit in this case. (A) shows the differential waveform when no spark discharge occurs in the spark plug, and (b) shows the output from the peak hold unit in this case. It is a flowchart which shows the main routine of the process performed in a spark discharge detection apparatus. It is a flowchart which shows a spark discharge determination process.

Hereinafter, embodiments will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a block diagram showing a schematic configuration of an ignition device 101 having an ignition plug 1, a voltage application unit 31, and a spark discharge detection device 41. In FIG. 1, only one spark plug 1 is shown, but the internal combustion engine EN is provided with a plurality of cylinders, and the spark plugs 1 are provided corresponding to the respective cylinders. A voltage application unit 31 and a spark discharge detection device 41 are provided for each spark plug 1.

  First, prior to the description of the ignition device 101, a schematic configuration of the spark plug 1 will be described.

  As shown in FIG. 2, the spark plug 1 includes a cylindrical insulator 2, a cylindrical metal shell 3 that holds the insulator 2, and the like.

  As is well known, the insulator 2 is formed by firing alumina or the like, and in its outer portion, a rear end side body portion 10 formed on the rear end side, and a front end than the rear end side body portion 10. A large-diameter portion 11 that protrudes radially outward on the side, a middle body portion 12 that is smaller in diameter than the large-diameter portion 11, and a tip portion that is more distal than the middle body portion 12. The leg length part 13 formed in diameter smaller than this on the side is provided. In addition, of the insulator 2, the large diameter portion 11, the middle trunk portion 12, and most of the leg long portions 13 are accommodated inside the metal shell 3. A tapered step portion 14 is formed at the connecting portion between the middle body portion 12 and the long leg portion 13, and the insulator 2 is locked to the metal shell 3 at the step portion 14.

  Further, the insulator 2 is formed with a shaft hole 4 extending along the axis CL <b> 1, and a center electrode 5 is inserted and fixed to the tip side of the shaft hole 4. The center electrode 5 includes an inner layer 5A made of copper or a copper alloy and an outer layer 5B made of a Ni alloy containing nickel (Ni) as a main component. The center electrode 5 has a rod shape (cylindrical shape) as a whole, and a tip portion of the center electrode 5 projects from the tip of the insulator 2.

  In addition, a terminal electrode 6 is inserted and fixed on the rear end side of the shaft hole 4 in a state of protruding from the rear end of the insulator 2.

  Further, a cylindrical resistor 7 is disposed between the center electrode 5 and the terminal electrode 6 of the shaft hole 4. Both ends of the resistor 7 are electrically connected to the center electrode 5 and the terminal electrode 6 through conductive glass seal layers 8 and 9, respectively.

  In addition, the metal shell 3 is formed in a cylindrical shape from a metal such as low carbon steel, and a screw for attaching the spark plug 1 to a combustion device such as an internal combustion engine or a fuel cell reformer on the outer peripheral surface thereof. A portion (male screw portion) 15 is formed. Further, a seat portion 16 is formed on the rear end side of the screw portion 15 so as to protrude toward the outer peripheral side, and a ring-shaped gasket 18 is fitted into the screw neck 17 at the rear end of the screw portion 15. Further, a tool engaging portion 19 having a hexagonal cross section for engaging a tool such as a wrench when the metal shell 3 is attached to the combustion device is provided on the rear end side of the metal shell 3. A caulking portion 20 that bends inward in the radial direction is provided at the rear end portion of the metal shell 3.

  Furthermore, a tapered step portion 21 for locking the insulator 2 is provided on the inner peripheral surface of the metal shell 3. The insulator 2 is inserted from the rear end side to the front end side of the metal shell 3, and the rear end of the metal shell 3 is engaged with the step portion 14 of the metal shell 3. It is fixed to the metal shell 3 by caulking the opening on the side inward in the radial direction, that is, by forming the caulking portion 20. An annular plate packing 22 is interposed between the step portions 14 and 21 of both the insulator 2 and the metal shell 3. Thereby, the airtightness in the combustion chamber is maintained, and the fuel gas entering the gap between the leg long portion 13 of the insulator 2 exposed to the combustion chamber and the inner peripheral surface of the metal shell 3 is prevented from leaking outside.

  Further, in order to make the sealing by caulking more complete, annular ring members 23 and 24 are interposed between the metal shell 3 and the insulator 2 on the rear end side of the metal shell 3, and the ring member 23 , 24 is filled with talc 25 powder. That is, the metal shell 3 holds the insulator 2 via the plate packing 22, the ring members 23 and 24, and the talc 25.

  Further, the front end surface 26 of the metal shell 3 is joined with a ground electrode 27 which is bent back at a substantially intermediate portion of the metal shell 3 and whose front end side surface faces the front end portion of the center electrode 5. A spark discharge gap 28 is formed between the tip of the center electrode 5 and the tip of the ground electrode 27.

  In the spark plug 1 described above, a voltage is applied from the voltage application unit 31 to the spark discharge gap 28, so that a spark discharge is performed in a direction substantially along the axis CL1. Next, the configuration of the voltage application unit 31 will be described.

  As shown in FIG. 1, the voltage application unit 31 includes a primary coil 32, a secondary coil 33, a core 34, and an igniter 35.

  The primary coil 32 is wound around the core 34, one end of which is connected to the power supply device VA for supplying power, and the other end is connected to the igniter 35. The secondary coil 33 is wound around the core 34, and one end thereof is connected between the primary coil 32 and the power supply device VA, and the other end is connected to the terminal electrode 6 of the spark plug 1. ing.

  In addition, the igniter 35 is formed by a predetermined transistor, and in response to an energization signal input from a predetermined electronic control unit (ECU) 51, application and stop of application of the primary voltage from the power supply device VA to the primary coil 32 are performed. Switch. When a high voltage is applied to the spark plug 1, an energization signal from the ECU 51 to the igniter 35 is turned on, a primary voltage is applied from the power supply VA to the primary coil 32, and a magnetic field is formed around the core 34. The application of the primary voltage to the primary coil 32 is stopped by switching the energization signal from the ECU 51 from on to off. By stopping the primary voltage, the magnetic field of the core 34 changes, and a negative secondary voltage (several to several tens of kV) is generated in the secondary coil 33 by self-dielectric action. By applying this secondary voltage to the spark plug 1 (terminal electrode 6), a spark discharge is generated in the spark discharge gap 28.

  In the present embodiment, the ECU 51 is configured to be able to change the ON time of the energization signal for the igniter 35 and thus the energization time of the primary voltage to the primary coil 32. Specifically, the ECU 51 acquires when the air-fuel mixture is ignited (that is, when spark discharge occurs) by a combustion pressure sensor (not shown) provided in the internal combustion engine EN, and the like. The time (delay time) from the timing when the energization signal to the igniter 35 is turned off to the time when the spark discharge occurs can be acquired. When the delay time is equal to or longer than a predetermined permissible time (that is, when the spark discharge occurrence time is shifted from the target occurrence time by a predetermined time or more), the sparks are consumed due to the consumption of the electrodes 5 and 27. Since the voltage (required voltage) for causing spark discharge is considered to be high due to factors such as an increase in the discharge gap 28, the ECU 51 increases the ON time of the energization signal to the igniter 35. By increasing the energization time of the primary voltage, the voltage (secondary voltage) output from the voltage application unit 31 is increased. As a result, a potential difference exceeding the dielectric breakdown voltage of the spark discharge gap 28 can be generated more quickly between the electrodes 5 and 27, and as a result, the timing of occurrence of the spark discharge can be advanced. As a result, the spark discharge occurrence time can be brought close to the target occurrence time. Note that the primary voltage can be changed by configuring the output voltage from the power supply device VA to be increased or decreased by a booster circuit or the like, and spark discharge by changing the primary voltage or the primary voltage and its energization time. It is good also as adjusting the generation | occurrence | production time.

  Furthermore, in the present embodiment, a spark discharge detection device 41 that detects whether or not a spark discharge has occurred based on the voltage waveform applied to the spark plug 1 is provided. A voltage waveform detection unit 42 and a microcomputer 43 are provided.

  The voltage waveform detection unit 42 acquires a voltage waveform corresponding to the voltage applied to the spark plug 1 and inputs the voltage waveform to the microcomputer 43. The spark plug 1 and the voltage application unit 31 (secondary coil) 33). In the present embodiment, the voltage waveform detection unit 42 is configured by a capacitance-type voltage sensor, and has a voltage value that is substantially the same as the voltage waveform that is actually applied to the spark plug 1 and that has a voltage value. A sufficiently reduced voltage waveform is input to the microcomputer 43.

  The voltage waveform applied to the spark plug 1 may be directly acquired and the voltage waveform may be input to the microcomputer 43. However, in this case, the applied voltage to the spark plug 1 is a high voltage. The microcomputer must have sufficient withstand voltage performance. On the other hand, by using a capacitance type voltage sensor as the voltage waveform detection unit 42 as in the present embodiment, it is not necessary to use a microcomputer having high withstand voltage performance, and a relatively inexpensive microcomputer. Can be used. Another advantage of using a capacitive voltage sensor is that the influence of noise in the voltage waveform can be reduced.

  The microcomputer 43 is configured to be communicable with the ECU 51, and includes a differentiation processing unit 44, a discharge detection unit 45, a determination period setting unit 46, and a threshold setting unit 47.

  The differentiation processing unit 44 is configured by a differentiation circuit, and outputs a differential waveform obtained by differentiating the voltage waveform input from the voltage waveform detection unit 42 to the discharge detection unit 45.

  The discharge detection unit 45 acquires the value of the differential waveform output from the differentiation processing unit 44 at each predetermined timing, and compares the acquired value of the differential waveform with a predetermined determination threshold value. Then, when the value of the differential waveform exceeds the determination threshold value, an interrupt process is performed, and when the interrupt process applies a voltage from the voltage application unit 31 to the spark plug 1 (from the ECU 51). When the energization signal is turned on from off to a predetermined determination period, a spark flag indicating that a spark discharge has occurred is established (that is, the differential waveform during the determination period). The discharge detection unit 45 determines that a spark discharge has occurred normally in the spark plug 1 and establishes a spark flag). On the other hand, the flying flag is reset before the next voltage application timing to the spark plug 1 by the voltage application unit 31 (that is, before the next determination period).

  When a spark discharge occurs in the spark plug 1, for example, as shown in FIGS. 3A and 4A, the voltage waveform varies depending on the magnitude of the required voltage. Following the capacitive discharge in which the voltage value changes rapidly, an induction discharge in which a minute current flows is generated. Therefore, as shown in FIGS. 3B and 4B, the differential waveform obtained by differentiating the voltage waveform greatly fluctuates during the capacity discharge, and the peak value of the differential waveform is equal to the threshold for determination. It will exceed.

  On the other hand, when no spark discharge occurs in the spark plug 1, for example, as shown in FIG. 5A, the voltage waveform is a capability waveform indicating the time change of the secondary voltage output from the voltage application unit 31. It becomes. Therefore, as shown in FIG. 5B, the differential waveform obtained by differentiating the voltage waveform hardly fluctuates, and the peak value of the differential waveform is equal to or less than the determination threshold value.

  Further, the discharge detection unit 45 is set to a preset predetermined time (in this embodiment, the time from the voltage application timing to the ignition plug 1 by the voltage application unit 31 to immediately before the next voltage application timing, Normally, the number of times it is determined that a spark discharge has occurred in the spark plug 1 within this time (with two spark discharges occurring within this time) is set to a predetermined number of times (0 in this embodiment). Times) or less, it is determined that an abnormality has occurred in at least one of the spark plug 1 and the voltage application unit 31.

  Specifically, the discharge detection unit 45 performs a spark discharge determination process after the determination period has elapsed and before the next determination period. In the spark discharge determination process, first, it is checked whether or not the flying flag is established. That is, it is checked whether or not the spark discharge has occurred normally during the determination period. When the flying flag is not established, the value of the error counter (the initial value is set to 0) indicating the number of times the abnormality has occurred in the spark discharge is increased by 1, while the flying flag is established. If it is, the error counter value is cleared (0). Then, when the numerical value of the error counter becomes equal to or larger than a predetermined value (2 in the present embodiment) during the predetermined time, the discharge detection unit 45 gives a determination result indicating that the spark discharge is abnormal. Error processing is performed in the ECU 51 that has transmitted to the ECU 51 and received the determination result. In the present embodiment, as an error process, a process of notifying a driver or the like that an abnormality has occurred in the spark plug 1 or the voltage application unit 31 is performed (that is, in the present embodiment, the ECU 51 performs a notification unit). As a function).

  In addition, the determination period setting unit 46 sets the determination period based on the primary voltage applied to the primary coil 32 and the energization time of the primary voltage to the primary coil 32. Specifically, the voltage waveform (capacity waveform) when the secondary voltage is output from the voltage application unit 31 on the desk after variously changing the primary voltage to the primary coil 32 and the energization time of the primary voltage is a voltage. A map that is measured by the waveform detector 42 and shows the relationship between the primary voltage and its energization time and the time width of the capability waveform is obtained in advance. Based on the primary voltage in the voltage application unit 31 and the energization time of the primary voltage, the determination period setting unit 46 has a capability waveform that can be generated by the secondary voltage output from the voltage application unit 31 from the map. A time width is obtained and the time width is set as a determination period. Accordingly, when the energization time of the primary voltage is changed by the ECU 51, the determination period is set according to the change.

  Further, the threshold setting unit 47 sets a determination threshold based on the primary voltage and the energization time of the primary voltage. Specifically, the voltage waveform (capacity waveform) when the secondary voltage is output from the voltage application unit 31 on the desk after variously changing the primary voltage to the primary coil 32 and the energization time of the primary voltage is a voltage. Measured by the waveform detector 42, the peak value of the differential value of the voltage waveform [a reference value when setting a threshold for determination (threshold reference value)], the magnitude of the primary voltage, and the energization time of the primary voltage, A map showing the relationship (for example, see FIG. 6) is obtained in advance. Then, the threshold setting unit 47 acquires a peak value (threshold reference value) corresponding to the primary voltage in the voltage application unit 31 and its energization time based on the map, and sets a predetermined numerical value (for example, 2 or more) is set as a threshold for determination. Accordingly, when the energization time of the primary voltage is changed by the ECU 51, the determination threshold is set in accordance with the change. Further, since a value obtained by multiplying the peak value by a predetermined numerical value is used as a determination threshold value, whether or not a spark discharge is generated by the discharge detection unit 45 even when a slight fluctuation occurs in the differential waveform due to the influence of noise. It is possible to accurately detect whether or not.

  Next, a specific example of a spark discharge detection method by the spark discharge detection device 41 will be described with reference to the flowcharts of FIGS.

  As shown in FIG. 7, in S <b> 1, the value of the differential waveform output from the differential processing unit 44 is compared with the determination threshold at every predetermined timing. When the value of the differential waveform exceeds the determination threshold value (S1; Yes), an interrupt process is performed (S2), and when the value of the differential waveform is equal to or less than the determination threshold value (S1; No), the interrupt process (S2) is skipped and the process proceeds to S3.

  In the interrupt process (S2), as shown in FIG. 8, first, whether or not the interrupt process is performed during the determination period, that is, during the determination period, the value of the differential waveform is determined as a determination threshold value. Is determined (S21). If it is within the determination period (S21; Yes), the flying flag is established (S22), and the process proceeds to S3. Note that the initial value of the flying fire flag is 0.

  Returning to FIG. 7, it is determined whether or not the determination period has elapsed in S <b> 3. When the determination period has elapsed (S <b> 3; No), the process proceeds to S <b> 5 and subsequent steps. On the other hand, when it is within the determination period (S3; Yes), the processing flag is reset (S4), and the process returns to S1. The processing flag is a flag used for determination for performing the spark discharge determination processing only once after the determination period elapses and before the next determination period, and has an initial value of 0.

  In S5, it is checked whether or not a processing flag is established, and it is checked whether or not the spark discharge determination process (S6) has already been performed after the determination period has elapsed and before the start of the next determination period. Here, when 1 is set in the processing flag (S5; No), since the spark discharge determination process has already been performed after the determination period and before the next determination period, S6 is skipped. Then, the process proceeds to S7. On the other hand, when the processing flag is 0 (S5; Yes), a spark discharge determination process is performed (S6).

  In the spark discharge determination process, as shown in FIG. 9, first, it is checked whether or not the flying flag is established (S61). Here, when the flying flag is established (S61; Yes), it is considered that the spark discharge has occurred normally during the determination period, so the error counter is cleared (0) (S62). On the other hand, when the flying flag is not established (S61; No), the value of the error counter is increased by one (S63). In S64, it is determined whether or not the value of the error counter is greater than or equal to a predetermined value (2 in the present embodiment). If the value of the error counter is greater than or equal to the predetermined value (S64; Yes), an error is detected. Processing is performed (S65). Next, as shown in FIG. 7, after the spark discharge determination process (S6), the process flag is set to 1 in S7 so that the spark discharge determination process is not performed again before the next determination period. . In S8, the flying flag is reset.

  As described above in detail, according to the present embodiment, the peak value of the differential value of the voltage waveform is compared with a predetermined determination threshold value, and when the peak value exceeds the determination threshold value, spark discharge is generated. It is configured to determine that it has occurred. That is, the presence or absence of spark discharge is detected based on the peak value of the differential value of the voltage waveform that causes a large difference between when spark discharge occurs and when spark discharge does not occur. Therefore, even if a slight fluctuation occurs in the voltage waveform due to the influence of noise or the like, it can be detected with high accuracy whether or not a spark discharge has occurred.

  In addition, since the determination period is set by the determination period setting unit 46 based on the primary voltage and the energization time of the primary voltage, the peak value of the differential value during the period in which the spark discharge can occur can be obtained more reliably. it can. Further, since the threshold value for determination is set by the threshold setting unit 47 based on the primary voltage and the energization time of the primary voltage, a more appropriate threshold value for determination corresponding to the voltage applied to the spark plug 1 is set. Can do. Thus, by making it possible to change the determination period and the determination threshold value, it is possible to further improve the detection accuracy of the spark discharge.

Furthermore, when the number of detections of the spark discharge is less than the predetermined number within a predetermined time set in advance, it is configured to notify that an abnormality has occurred in the spark plug 1 or the voltage application unit 31. Yes. Therefore, the abnormal state can be quickly eliminated by replacing the spark plug 1 or the like, and the situation where the output decrease or the deterioration of the fuel consumption continues for a long period can be more reliably prevented.
[Second Embodiment]
Next, the second embodiment will be described focusing on differences from the first embodiment. In the second embodiment, as shown in FIG. 10, a peak hold (P / H) unit 48 (peak hold circuit) to which a differential waveform output from the differential processing unit 44 is input is provided.

  The peak hold unit 48 holds the peak value of the differential waveform from the time when the voltage is applied to the spark plug 1 from the voltage application unit 31 until the next time the voltage is applied to the spark plug 1 at the longest. The held peak value is output to the discharge detection unit 45. Therefore, for example, as shown in FIG. 11A, when spark discharge occurs in the spark plug 1, the peak value to be held (holding peak value) is relatively low as shown in FIG. 11B. It becomes large and exceeds the threshold for determination. On the other hand, as shown in FIG. 12A, when spark discharge does not occur in the spark plug 1, for example, as shown in FIG. Below the threshold for use. The holding peak value is reset immediately before the next voltage application timing to the spark plug 1 by the voltage application unit 31 (that is, before the next determination period).

  Next, a specific example of the spark discharge detection method according to the second embodiment will be described with reference to the flowcharts of FIGS.

  As shown in FIG. 13, first, it is determined whether or not the determination period has elapsed in S11. When the determination period has elapsed (S11; No), the process proceeds to S13 and subsequent steps, and is within the determination period. Sometimes (S11; Yes), the processing flag is reset (S12), and the process returns to S11.

  In S13, it is checked whether or not a processing flag is established, and after the determination period has elapsed, it is checked whether or not a spark discharge determination process has already been performed before the next determination period. Here, when the processing flag is set to 1 (S13; No), since the spark discharge determination process has already been performed after the determination period and before the next determination period, S14 is skipped. Then, the process proceeds to S15. On the other hand, when the processing flag is 0 (S13; No), a spark discharge determination process is performed (S14).

  In the spark discharge determination process, as shown in FIG. 14, first, in S141, it is determined whether or not the retention peak value is greater than or equal to a determination threshold value (within a determination period before the spark discharge determination process is performed). In addition, the peak value of the differential waveform is already held). Here, when the retention peak value exceeds the determination threshold value (S141; Yes), it is considered that the spark discharge has occurred normally during the determination period, so the error counter is cleared (0). (S142). On the other hand, when the retention peak value is equal to or smaller than the determination threshold value (S141; No), the error counter value is incremented by one (S143). In S144, it is determined whether or not the value of the error counter is equal to or greater than a predetermined value (2 in the present embodiment). At this time, if the value of the error counter is greater than or equal to a predetermined value (S144; Yes), error processing is performed (S145).

  Returning to FIG. 13, after the spark discharge determination process, the processing flag is set to 1 so that the spark discharge determination process is not performed again before the next determination period (S15). Further, the holding peak value is reset (S16).

  As described above, according to the second embodiment, the same operational effects as those of the first embodiment are basically obtained.

  Further, according to the second embodiment, the peak value of the differential waveform can be obtained more accurately. Furthermore, the discharge detection unit 45 determines whether or not a spark discharge has occurred by comparing the held peak value with a determination threshold value. Therefore, it is not necessary to check at any time whether the value of the differential waveform exceeds the determination threshold value, and the processing load on the discharge detection unit 45 can be reduced. Further, by reducing the processing load, the detection process can be performed with sufficient accuracy even if the processing capacity of the discharge detection unit 45 is not so high. Further, it is possible to reduce the manufacturing cost.

  In addition, it is not limited to the description content of the said embodiment, For example, you may implement as follows. Of course, other application examples and modification examples not illustrated below are also possible.

  (A) In the above embodiment, the error counter is cleared when the spark discharge is normally performed within the determination period, but the error counter value is decreased without clearing the error counter value. You may comprise as follows.

  (B) In the above embodiment, the voltage application unit 31 is provided for each spark plug 1, but the power from the voltage application unit 31 is supplied to the distributor without providing the voltage application unit 31 for each spark plug 1. It is good also as supplying to each spark plug 1 via.

  (C) In the above embodiment, the spark discharge detection device 41 is provided for each spark plug 1, but a smaller number of spark discharge detection devices 41 than the number of spark plugs 1 may be provided. While the voltage waveform detector 42 is provided for each spark plug 1, a smaller number of microcomputers 43 than the number of spark plugs 1 may be provided. In this case, the spark discharge in each ignition plug 1 can be detected by a small number of devices by selectively inputting the voltage waveform of each ignition plug 1 at the discharge timing to the microcomputer 43, and the manufacturing cost is reduced. Can be further suppressed.

  (D) The configuration of the spark plug 1 in the above embodiment is merely an example, and the spark plug 1 to which the present invention is applicable is not particularly limited.

DESCRIPTION OF SYMBOLS 1 ... Spark plug 31 ... Voltage application part 32 ... Primary coil 33 ... Secondary coil 41 ... Spark discharge detection apparatus 44 ... Differentiation processing part 45 ... Discharge detection part 46 ... Determination period setting part 47 ... Threshold setting part 48 ... Peak hold part

Claims (8)

An ignition device comprising: an ignition plug; and a voltage application unit that applies a voltage to the ignition plug, wherein a spark discharge is generated in the ignition plug by applying a voltage from the voltage application unit to the ignition plug. A spark discharge detection method for detecting a spark discharge in
The peak value of the differential value of the voltage waveform corresponding to the voltage applied to the spark plug has a predetermined threshold for determination during a predetermined determination period from the time when the voltage is applied to the spark plug from the voltage application unit. When exceeded, it is determined that a spark discharge has occurred in the spark plug ,
The voltage application unit includes a primary coil to which a primary voltage is applied from a predetermined power supply device, and a secondary coil that generates a high voltage for spark discharge by stopping application of the primary voltage to the primary coil,
The spark discharge detection method , wherein the threshold for determination is set based on the primary voltage and the energization time of the primary voltage to the primary coil . An ignition device comprising: an ignition plug; and a voltage application unit that applies a voltage to the ignition plug, wherein a spark discharge is generated in the ignition plug by applying a voltage from the voltage application unit to the ignition plug. A spark discharge detection method for detecting a spark discharge in
The differential value of the voltage waveform corresponding to the voltage applied to the spark plug from the time when the voltage is applied to the spark plug from the voltage application unit until the next time the voltage is applied to the spark plug. When the peak value held exceeds a predetermined threshold for determination , it is determined that a spark discharge has occurred in the spark plug ,
The voltage application unit includes a primary coil to which a primary voltage is applied from a predetermined power supply device, and a secondary coil that generates a high voltage for spark discharge by stopping application of the primary voltage to the primary coil,
The spark discharge detection method , wherein the threshold for determination is set based on the primary voltage and the energization time of the primary voltage to the primary coil . Before Symbol primary voltage, on the basis of the energization time of the primary voltage to the primary coil, spark discharge detection method according to claim 1, characterized in that sets the determination period. When the number of times determined that spark discharge has occurred in the spark plug within a preset predetermined time is less than the preset predetermined number of times, the spark plug and the voltage application unit spark discharge detection method according to any one of claims 1 to 3, wherein the notifying the abnormality in at least one has occurred. An ignition device comprising: an ignition plug; and a voltage application unit that applies a voltage to the ignition plug, wherein a spark discharge is generated in the ignition plug by applying a voltage from the voltage application unit to the ignition plug. A spark discharge detection device for detecting spark discharge in
The peak value of the differential value of the voltage waveform corresponding to the voltage applied to the spark plug has a predetermined threshold for determination during a predetermined determination period from the time when the voltage is applied to the spark plug from the voltage application unit. A discharge detector that determines that a spark discharge has occurred in the spark plug when exceeded ,
The voltage application unit includes a primary coil to which a primary voltage is applied from a predetermined power supply device, and a secondary coil that generates a high voltage for spark discharge by stopping application of the primary voltage to the primary coil,
And the primary voltage, on the basis of the energization time of the primary voltage to the primary coil, spark discharge detection device according to claim Rukoto to have a threshold value setting unit capable of setting the determination threshold value. An ignition device comprising: an ignition plug; and a voltage application unit that applies a voltage to the ignition plug, wherein a spark discharge is generated in the ignition plug by applying a voltage from the voltage application unit to the ignition plug. A spark discharge detection device for detecting spark discharge in
The differential value of the voltage waveform corresponding to the voltage applied to the spark plug from the time when the voltage is applied to the spark plug from the voltage application unit until the next time the voltage is applied to the spark plug. A peak hold section for holding the peak value of
A discharge detection unit that determines that a spark discharge has occurred in the spark plug when a peak value held by the peak hold unit exceeds a predetermined determination threshold ;
The voltage application unit includes a primary coil to which a primary voltage is applied from a predetermined power supply device, and a secondary coil that generates a high voltage for spark discharge by stopping application of the primary voltage to the primary coil,
And the primary voltage, on the basis of the energization time of the primary voltage to the primary coil, spark discharge detection device according to claim Rukoto to have a threshold value setting unit capable of setting the determination threshold value. Before Symbol primary voltage, on the basis of the energization time of the primary voltage to the primary coil, spark discharge detection device according to claim 5, characterized in that it comprises the determination period settable determination period setting unit. When the number of times determined that spark discharge has occurred in the spark plug within a preset predetermined time is less than the preset predetermined number of times, the spark plug and the voltage application unit The spark discharge detection device according to any one of claims 5 to 7 , further comprising a notification unit that notifies that at least one of the abnormality has occurred.

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