WO2022038930A1 - 内燃機関の点火装置 - Google Patents

内燃機関の点火装置 Download PDF

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Publication number
WO2022038930A1
WO2022038930A1 PCT/JP2021/026588 JP2021026588W WO2022038930A1 WO 2022038930 A1 WO2022038930 A1 WO 2022038930A1 JP 2021026588 W JP2021026588 W JP 2021026588W WO 2022038930 A1 WO2022038930 A1 WO 2022038930A1
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WIPO (PCT)
Prior art keywords
discharge
period
internal combustion
combustion engine
ignition device
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2021/026588
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English (en)
French (fr)
Japanese (ja)
Inventor
明光 杉浦
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Denso Corp
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Denso Corp
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Publication date
Application filed by Denso Corp filed Critical Denso Corp
Publication of WO2022038930A1 publication Critical patent/WO2022038930A1/ja
Priority to US18/110,539 priority Critical patent/US11939943B2/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
    • F02P13/00—Sparking plugs structurally combined with other parts of internal-combustion engines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B19/00—Engines characterised by precombustion chambers
    • F02B19/12—Engines characterised by precombustion chambers with positive ignition
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
    • F02P15/00—Electric spark ignition having characteristics not provided for in, or of interest apart from, groups F02P1/00 - F02P13/00 and combined with layout of ignition circuits
    • F02P15/10—Electric spark ignition having characteristics not provided for in, or of interest apart from, groups F02P1/00 - F02P13/00 and combined with layout of ignition circuits having continuous electric sparks
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T13/00—Sparking plugs
    • H01T13/54—Sparking plugs having electrodes arranged in a partly-enclosed ignition chamber
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T15/00—Circuits specially adapted for spark gaps, e.g. ignition circuits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
    • F02P9/00—Electric spark ignition control, not otherwise provided for
    • F02P9/002—Control of spark intensity, intensifying, lengthening, suppression
    • F02P9/007—Control of spark intensity, intensifying, lengthening, suppression by supplementary electrical discharge in the pre-ionised electrode interspace of the sparking plug, e.g. plasma jet ignition
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Definitions

  • This disclosure relates to an ignition device for an internal combustion engine.
  • a spark plug provided with an auxiliary combustion chamber is disclosed in Patent Document 1.
  • the air-fuel mixture in the sub-combustion chamber is ignited by the discharge generated in the discharge gap in the sub-combustion chamber.
  • the flame formed in the sub-combustion chamber is ejected as a flame jet into the main combustion chamber through the injection hole. Thereby, combustion in the main combustion chamber can be promoted.
  • the spark plug equipped with the sub-combustion chamber has room for improvement in terms of ignitability in the sub-combustion chamber. Therefore, in the ignition device of an internal combustion engine having such a spark plug, it can be said that there is room for strengthening the flame jet from the auxiliary combustion chamber to the main combustion chamber to improve the combustion efficiency of the main combustion chamber.
  • the present disclosure is intended to provide an ignition device for an internal combustion engine capable of improving combustion efficiency.
  • One aspect of the present disclosure is a spark plug having an auxiliary combustion chamber in which a discharge gap is arranged.
  • An ignition coil that applies voltage to the spark plug and A control unit that controls the discharge in the spark plug,
  • An internal combustion engine igniter with The control unit is configured to be able to execute a plurality of discharge modes in which a plurality of discharges are generated in the discharge gap between the compression stroke and the expansion stroke of the internal combustion engine with a discharge suspension period in between. It is in the ignition device of the internal combustion engine.
  • the control unit can execute a plurality of discharge modes in which a plurality of discharges are generated in the discharge gap between the compression stroke and the expansion stroke of the internal combustion engine with a discharge pause period in between. It is configured as. Therefore, in the plurality of discharge modes, a plurality of initial flames can be generated in the sub-combustion chamber by a plurality of discharges. Therefore, these plurality of initial flames can be polymerized in the sub-combustion chamber to improve the ignitability in the sub-combustion chamber. As a result, the flame jet from the sub-combustion chamber to the main combustion chamber of the internal combustion engine can be strengthened, and the combustion efficiency in the main combustion chamber can be improved.
  • FIG. 1 is an explanatory diagram of an ignition device for an internal combustion engine according to the first embodiment.
  • FIG. 2 is a cross-sectional view of the tip of the spark plug in the first embodiment.
  • FIG. 3 is a timing chart of the ignition signal, the primary current, and the secondary current in the first embodiment.
  • FIG. 4 is a timing chart of the ignition signal, the primary current, and the secondary current near the TDC in the first embodiment.
  • FIG. 5 is an explanatory diagram of a swirl flow in a compression stroke corresponding to a cross section taken along the line VV of FIG. 2 in the first embodiment.
  • FIG. 1 is an explanatory diagram of an ignition device for an internal combustion engine according to the first embodiment.
  • FIG. 2 is a cross-sectional view of the tip of the spark plug in the first embodiment.
  • FIG. 3 is a timing chart of the ignition signal, the primary current, and the secondary current in the first embodiment.
  • FIG. 4 is a timing chart of the ignition signal, the primary current, and the secondary current
  • FIG. 6 is an explanatory diagram of the swirl flow of the expansion stroke in the first embodiment.
  • FIG. 7 is a timing chart of the flow velocity, the primary current, and the secondary current of the air flow in the second embodiment.
  • FIG. 8 is a timing chart of the discharge maintenance voltage in the third embodiment.
  • FIG. 9 is a flow chart of the discharge suspension determination method using the discharge maintenance voltage in the third embodiment.
  • FIG. 10 is a timing chart of the discharge current in the third embodiment.
  • FIG. 11 is a flow chart of the discharge suspension determination method using the discharge current attenuation rate in the third embodiment.
  • FIG. 12 is a timing chart of the ignition signal, the primary current, and the secondary current near the TDC in the fourth embodiment.
  • FIG. 13 is a cross-sectional view of the tip of the spark plug in the fourth embodiment.
  • the ignition device 10 of the internal combustion engine of this embodiment has a spark plug 1, an ignition coil 7, and a control unit 8.
  • the spark plug 1 has an auxiliary combustion chamber 50 in which the discharge gap G is arranged.
  • the ignition coil 7 applies a voltage to the spark plug 1.
  • the control unit 8 controls the discharge in the spark plug 1.
  • the control unit 8 is configured to be able to execute a plurality of discharge modes. In the multiple discharge mode, a plurality of discharges are generated in the discharge gap G with the discharge pause period DP in between from the compression stroke to the expansion stroke of the internal combustion engine.
  • the control unit 8 can be configured by, for example, an ECU for a vehicle (that is, an electronic control unit).
  • the control unit 8 transmits the ignition signal IGt to the ignition coil 7 at a predetermined timing. Based on this ignition signal IGt, the ignition coil 7 applies a high voltage to the spark plug 1. As a result, a discharge is generated in the discharge gap G in the spark plug 1.
  • the ignition device 10 of this embodiment can be used as an ignition means in an internal combustion engine such as an automobile or a cogeneration engine, for example. Then, as shown in FIG. 1, one end of the spark plug 1 in the axial direction Z is arranged in the main combustion chamber 11 of the internal combustion engine. In the axial direction Z of the spark plug 1, the side exposed to the main combustion chamber 11 is referred to as the distal end side, and the opposite side thereof is referred to as the proximal end side.
  • the spark plug 1 has a tubular insulating insulator 3, a center electrode 4, a tubular housing 2, a ground electrode 6, and a plug cover 5.
  • the center electrode 4 is held on the inner peripheral side of the insulating insulator 3 and protrudes from the insulating insulator 3 toward the tip end side.
  • the tip of the center electrode 4 is provided with a laterally projecting portion 41 projecting outward in the radial direction.
  • a discharge gap G is formed between the lateral protrusion 41 and the ground electrode 6.
  • the housing 2 holds the insulating insulator 3 on the inner peripheral side.
  • the housing 2 includes a mounting screw portion 23 for mounting the spark plug 1 to the internal combustion engine.
  • the plug cover 5 is provided at the tip of the housing 2.
  • the plug cover 5 has a plurality of injection holes 51.
  • the plurality of injection holes 51 are formed so that a swirl flow (see arrow A1 in FIG. 5) is generated in the sub-combustion chamber 50 by the air flow introduced into the sub-combustion chamber 50 through the injection holes 51.
  • a swirl flow see arrow A1 in FIG. 5
  • the spark plug 51 is formed in a state where the spark plug shaft 51L does not pass through the plug central axis PC.
  • the injection hole shaft 51L does not pass through the center electrode 4.
  • the ground electrode 6 is arranged to face the protruding end of the lateral protruding portion 41 of the center electrode 4 from the outer peripheral side.
  • the ground electrode 6 projects from the joint portion between the tip end of the housing 2 and the base end of the plug cover 5 toward the center electrode 4 in the plug radial direction.
  • the discharge gap G is arranged on the tip side of the tip of the housing 2.
  • the internal combustion engine is a so-called four-cycle engine, and the reciprocating motion of the piston 14 shown in FIG. 1 and the opening / closing of the intake valve 12 and the exhaust valve 13 are performed so as to sequentially repeat the intake stroke, the compression stroke, the expansion stroke, and the exhaust stroke. Will be done.
  • reference numeral 120 indicates an intake port
  • reference numeral 130 indicates an exhaust port.
  • the ignition device 10 causes the spark plug 1 to be discharged a plurality of times at a predetermined crank angle of the piston 14. That is, the control unit 8 transmits an ignition signal IGt at a predetermined timing with respect to the crank angle of the piston 14, and applies a high voltage from the ignition coil 7 to the spark plug 1.
  • the ignition coil 7 has a primary coil and a secondary coil that are magnetically coupled to each other.
  • the primary coil is connected to a DC power supply, and a primary current is supplied from the DC power supply based on the ignition signal IGt by the control unit 8.
  • a primary current is supplied from the DC power supply based on the ignition signal IGt by the control unit 8.
  • FIG. 3 is a timing chart showing an example of the timing of the ignition signal IGt, the primary current I1, and the secondary current I2 with respect to the crank angle in the multiple discharge modes.
  • TDC attached to the lower part of the figure indicates the compression top dead center. In the following, the compression top dead center is also referred to as TDC as appropriate.
  • BTDC 180 ° indicates the crank angle 180 ° before the compression top dead center, and ATDC 180 ° indicates the crank angle 180 ° after the compression top dead center.
  • a discharge is generated in the vicinity of the TDC depending on the operating state. For example, when the engine is heavily loaded or when the catalyst is in early warm-up to idle, it is common practice to ignite the air-fuel mixture in the vicinity of the TDC. Specifically, for example, a discharge is generated between BTDC 10 ° and ATDC 10 °, more preferably between BTDC 5 ° and ATDC 7 °.
  • the inventors of the present application have found that there is a concern that the ignitability of the spark plug 1 provided with the auxiliary combustion chamber 50 may be particularly deteriorated when a discharge is generated in the vicinity of the TDC. That is, the airflow flows into the sub-combustion chamber 50 from the main combustion chamber 11 through the injection hole 51, or the airflow flows out to the main combustion chamber 11. Therefore, as shown in FIGS. 5 and 6, airflows A1 and A2 are generated even in the auxiliary combustion chamber 50. When the discharge S generated in the discharge gap G is stretched by this air flow, the ignitability in the auxiliary combustion chamber 50 is enhanced.
  • the velocity of the airflow in the auxiliary combustion chamber 50 tends to decrease. That is, since it is close to the timing at which the inflow of the airflow into the sub-combustion chamber 50 and the outflow of the airflow from the sub-combustion chamber 50 are switched, the airflow in the sub-combustion chamber 50 weakens or becomes turbulent, resulting in airflow. The speed drops temporarily. Since the discharge generated in the discharge gap G at such a timing is difficult to be stretched by the air flow, there is a concern that the ignitability may be deteriorated.
  • a plurality of discharge modes are executed to generate a plurality of discharges as described above, thereby improving the ignitability in the auxiliary combustion chamber 50.
  • the control unit 8 causes the discharge gap G of the spark plug 1 to generate a plurality of discharges with the discharge pause period DP sandwiched between them, as shown in FIG.
  • the control unit 8 is configured to generate at least one discharge in the expansion stroke.
  • the generation of the secondary current I2 shown in FIGS. 3 and 4 means the generation of discharge. That is, the portion where the line indicating the secondary current I2 in the figure protrudes downward represents the occurrence of discharge.
  • discharge pause period DP means a period during which no discharge occurs between a plurality of discharges that occur intermittently in one cycle. Therefore, the period before the first discharge of the plurality of discharges in one cycle and after the last discharge is not the "discharge pause period DP".
  • two discharges are generated with the discharge pause period DP in between.
  • the two discharges are made to occur across the TDC. That is, the time when the first discharge starts is before the TDC, and the time when the second discharge ends is after the TDC. Further, the discharge pause period DP between the two discharges is made to exist across the TDC. It should be noted that these two discharges can be generated between BTDC 10 ° and ATDC 10 °, more preferably between BTDC 5 ° and ATDC 7 °.
  • the first discharge is generated immediately before TDC (for example, between BTDC 5 ° and 1 °).
  • the discharge pause period DP is provided from immediately before to immediately after the TDC.
  • a second discharge is generated immediately after the TDC (for example, between 3 ° and 7 ° ATDC).
  • the control unit 8 first applies the ignition signal IGt to the ignition coil 7 (more specifically, the igniter of the ignition coil 7) for a predetermined period before the TDC.
  • the primary current I1 is supplied to the primary coil of the ignition coil 7 to charge the ignition coil 7.
  • the primary current I1 gradually increases.
  • the ignition signal IGt is turned off and the primary current I1 is cut off.
  • the first discharge occurs in the discharge gap G, and the secondary current I2 flows.
  • the ignition signal IGt is turned on again, and the primary current I1 is started to be supplied to the primary coil. As a result, the first discharge is stopped and the discharge pause period DP starts. Then, immediately after the TDC (for example, ATDC 3 °), the ignition signal IGt is turned off to cut off the primary current I1. As a result, a second discharge occurs in the discharge gap G. That is, a second discharge is performed immediately after the TDC, and the secondary current I2 flows again.
  • the discharge pause period DP (that is, the period of the second ignition signal IGt on) is shorter than the charging period of the first ignition coil 7 (that is, the period of the first ignition signal IGt on). Further, the discharge pause period DP can be, for example, a length corresponding to 3 ° to 6 ° in terms of the advancement of the crank angle.
  • the velocity of the airflow in the auxiliary combustion chamber 50 decreases, and the velocity of the airflow in the discharge gap G (hereinafter, also appropriately referred to as “gap flow velocity vg”) decreases.
  • the timing at which the gap flow velocity vg decreases is set within the discharge pause period DP. That is, the gap flow velocity vg decreases in the discharge pause period DP, and the gap flow velocity vg in the first discharge period and the gap flow velocity vg in the second discharge period are larger than the gap flow velocity vg in the discharge pause period DP. Try to be high.
  • the gap flow velocity vg is lower in the discharge pause period DP at least once than in the discharge period immediately before and after the discharge pause period DP. If the gap flow velocity vg changes during each period, the average velocity during that period shall be used for comparison.
  • the control unit 8 does not execute the plurality of discharge modes in all the cycles, and may or may not execute the plurality of discharge modes depending on the operating state of the internal combustion engine.
  • the plurality of discharge modes can be configured to be executed only when ignition is performed in the vicinity of the TDC, such as when the engine is heavily loaded or when the catalyst is quickly warmed up to idle.
  • the control unit 8 causes a plurality of discharges in the discharge gap G with the discharge pause period DP sandwiched between the compression stroke and the expansion stroke of the internal combustion engine. Is configured to run. Therefore, in the plurality of discharge modes, a plurality of initial flames can be generated in the auxiliary combustion chamber 50 by a plurality of discharges. Therefore, these plurality of initial flames can be polymerized in the sub-combustion chamber 50 to improve the ignitability in the sub-combustion chamber 50. As a result, the flame jet from the sub-combustion chamber 50 to the main combustion chamber 11 of the internal combustion engine can be strengthened, and the combustion efficiency in the main combustion chamber 11 can be improved.
  • control unit 8 is configured to generate at least one discharge in the expansion stroke. This makes it easier for at least one discharge to be stretched by the airflow generated during the expansion stroke. As a result, the ignitability can be improved.
  • the gap flow velocity vg is lower in the discharge pause period DP at least once than in the discharge period immediately before and after the discharge pause period DP. As a result, it is possible to easily extend the discharge generated before and after the discharge suspension period DP. On the other hand, by providing the discharge pause period DP at the timing when the gap flow velocity vg is low, the discharge energy can be stored and left in preparation for the expansion stroke in which the discharge is likely to be stretched.
  • a swirl flow A1 is generated in the auxiliary combustion chamber 50.
  • the direction of the swirl flow A1 at this time is clockwise in the figure.
  • a swirl flow A2 is generated in the auxiliary combustion chamber 50.
  • the direction of the swirl flow A2 at this time is counterclockwise in the figure, contrary to the compression stroke. Then, at the time of switching from the compression stroke to the expansion stroke, that is, in the vicinity of the TDC, the swirl flow is weakened.
  • the timing at which the speed of the swirl flow decreases is slightly different between the position near the injection hole 51 and the position far from the injection hole 51. At a position close to the injection hole 51, the timing at which the gap flow velocity vg decreases substantially coincides with the TDC. On the other hand, at a position far from the injection hole 51, the timing at which the gap flow velocity vg decreases is slightly delayed from the TDC (see the fourth embodiment described later). In this embodiment, since the discharge gap G is relatively close to the injection hole 51, the timing at which the gap flow velocity vg decreases is substantially the same as that of the TDC.
  • the first discharge and the second discharge are generated according to the change in the gap flow velocity vg as described above. That is, the first discharge is generated in the compression stroke immediately before the TDC at the time when the gap flow velocity vg is maintained, and the second discharge is in the expansion stroke after the gap flow velocity vg starts to increase. Is caused in.
  • the discharge is easily extended and the ignitability can be improved.
  • the flame jet from the sub-combustion chamber 50 to the main combustion chamber 11 can be strengthened to improve the combustion efficiency.
  • an ignition device for an internal combustion engine capable of improving combustion efficiency.
  • the low flow velocity period LP is matched with the discharge pause period DP.
  • the low flow velocity period LP is a period in which the gap flow velocity vg is lower than the flow velocity threshold value vs.
  • the flow velocity threshold value vs. can be set to, for example, 5 m / sec.
  • the period in which the gap flow velocity vg is less than 5 m / sec in the vicinity of the TDC can be defined as the low flow velocity period LP.
  • the control unit 8 stores the discharge suspension period DP as a specific period. That is, for example, the time change of the gap flow velocity vg (that is, the change of the gap flow velocity vg with respect to the crank angle) is measured or estimated at the time of engine performance adaptation in the engine design and trial production stage. Based on the measured or estimated time change of the gap flow velocity vg, the time when the gap flow velocity vg becomes less than the flow velocity threshold value vth, that is, the low flow velocity period LP is derived. Then, this low flow velocity period LP is stored in the control unit 8 as the discharge suspension period DP. That is, the period of the specific timing is stored in the control unit 8 in advance as the discharge suspension period DP.
  • the gap flow velocity vg can be measured directly with, for example, a heat ray current meter or the like. It is also possible to estimate the gap flow velocity vg by analysis such as CFD. When the gap flow velocity vg is directly measured, the measured value may fluctuate slightly for each cycle. Therefore, in this case, for example, the period in which the minimum measured value among the measured values for a plurality of cycles is less than the flow velocity threshold value vs. is defined as the low flow velocity period LP and the discharge suspension period DP.
  • control unit 8 controls the ignition signal IGt so that the discharge pause period DP stored as described above can be obtained.
  • Others are the same as those in the first embodiment.
  • the same reference numerals as those used in the above-mentioned embodiments represent the same components and the like as those in the above-mentioned embodiments, unless otherwise specified.
  • the low flow velocity period LP is set as the discharge suspension period DP, it is possible to avoid the discharge at the timing when the discharge is difficult to be stretched. Therefore, it is possible to refrain from inputting the discharge energy during a period unfavorable in terms of ignitability and to input the discharge energy during other periods. By that amount, the ignitability in the sub-combustion chamber 50 can be improved, and eventually the combustion efficiency can be improved. Further, since the control unit 8 stores the discharge suspension period DP as a specific period, ignition control can be easily and reliably performed. In addition, it has the same effect as that of the first embodiment.
  • At least one discharge pause period DP is when the decay rate ⁇ I2 / ⁇ t of the discharge maintenance voltage V2 or the discharge current I2 of the discharge immediately before the discharge falls below a predetermined threshold value. It is a form configured to be started at.
  • the discharge maintenance voltage V2 sequentially fluctuates immediately after the start of discharge. Then, when the discharge is stretched, the discharge maintenance voltage V2 becomes high. Therefore, it can be estimated that the higher the discharge maintenance voltage V2, the higher the gap flow velocity vg. On the contrary, it can be estimated that the lower the discharge maintenance voltage V2, the lower the gap flow velocity vg. Therefore, when the discharge maintenance voltage V2 falls below the predetermined voltage threshold value Vth, it can be determined that the gap flow velocity vg becomes lower than the predetermined flow rate threshold value vth (for example, 5 m / sec).
  • the predetermined voltage threshold value Vth for example, 5 m / sec.
  • FIG. 8 shows an example of the waveform of the discharge maintenance voltage V2 when the active discharge suspension is not performed.
  • the discharge maintenance voltage V2 may fluctuate significantly when viewed in minute time units. Therefore, the discharge maintenance voltage V2 is obtained, for example, as the average value of the discharge maintenance voltage for the most recent predetermined minute time.
  • the predetermined minute time can be, for example, 1 ° CA.
  • 1 ° CA means a time for a crank angle of 1 °.
  • a crank angle of 0 ° CA indicates TDC
  • ⁇ 5 ° CA indicates BTDC of 5 °. The same applies to FIG. 10 described later.
  • the discharge maintenance voltage V2 is relatively low because the state is before the discharge is stretched. That is, even if the discharge maintenance voltage V2 is smaller than the voltage threshold value Vth immediately after the start of discharge, the gap flow velocity vg is not necessarily low. Therefore, the discharge is not stopped for a predetermined period immediately after the start of discharge (for example, 3 ° CA).
  • FIG. 9 shows an example of the flow of determining the start of the discharge pause period DP (that is, determining the end of the first discharge) in consideration of the above.
  • the discharge maintenance voltage V2 is sequentially measured.
  • step S2 it is determined whether or not a predetermined period (for example, 3 ° CA) has elapsed after the start of discharge. Only when a predetermined period has elapsed after the start of discharge, the discharge maintenance voltage V2 and the voltage threshold value Vth are compared in step S3.
  • the discharge is stopped in step S4. That is, the discharge pause period DP is started.
  • the ignition device 10 includes a voltage detection unit for measuring the discharge maintenance voltage V2.
  • a voltage detection unit for example, a voltage detection circuit that detects the generated voltage V1 of the primary coil of the ignition coil 7 can be used.
  • the generated voltage V1 of the primary coil is not the discharge maintenance voltage V2 itself.
  • the discharge maintenance voltage V2 can be easily calculated from the generated voltage V1 of the primary coil and the turns ratio of the ignition coil 7.
  • the discharge current I2 decreases for a while immediately after the start of discharge.
  • the decay rate ⁇ I2 / ⁇ t of the discharge current I2 is not constant, and is larger as the discharge maintenance voltage V2 is larger and smaller as the discharge maintenance voltage V2 is smaller. That is, it can be estimated that the higher the decay rate ⁇ I2 / ⁇ t of the discharge current I2, the higher the gap flow velocity vg. Conversely, it can be estimated that the lower the decay rate ⁇ I2 / ⁇ t of the discharge current I2, the lower the gap flow velocity vg.
  • the gap flow velocity vg is lower than the flow velocity threshold value vth (for example, 5 m / sec).
  • the correlation between the decay rate ⁇ I2 / ⁇ t and the gap flow velocity vg is obtained in advance, and the decay rate ⁇ I2 / ⁇ t corresponding to the flow velocity threshold value vs of the gap flow velocity vg is obtained as the attenuation threshold value Fth. Then, when the measured attenuation rate ⁇ I2 / ⁇ t falls below the attenuation threshold value Fth, the first discharge is stopped. Note that FIG. 10 shows an example of the waveform of the discharge current I2 when this active discharge suspension is not performed.
  • the attenuation rate ⁇ I2 / ⁇ t is obtained as, for example, the average value of the attenuation rates in the most recent predetermined minute time.
  • the predetermined minute time can be, for example, 1 ° CA.
  • the discharge is not stopped for a predetermined period immediately after the start of discharge (for example, 3 ° CA).
  • FIG. 11 shows an example of the flow of determining the start of the discharge pause period DP (that is, determining the end of the first discharge) in consideration of the above.
  • the decay rate ⁇ I2 / ⁇ t is sequentially measured.
  • step S12 it is determined whether or not a predetermined period (for example, 3 ° CA) has elapsed after the start of discharge. Only when a predetermined period has elapsed after the start of discharge, the attenuation rate ⁇ I2 / ⁇ t and the attenuation threshold value Fth are compared in step S13.
  • the discharge is stopped in step S14. That is, the discharge pause period DP is started.
  • the ignition device 10 includes a current detection unit for measuring the discharge current I2.
  • a current detection unit for example, a current detection circuit that detects the current flowing in the wiring between the secondary coil of the ignition coil 7 and the ground can be used.
  • various settings can be made such that the second discharge start is, for example, after a predetermined time has elapsed from the start time of the discharge pause period DP.
  • the predetermined time here can be set in advance, for example. Others are the same as those in the first embodiment.
  • both V2 and ⁇ I2 / ⁇ t are monitored, and when either “V2 ⁇ Vth” or “ ⁇ I2 / ⁇ t ⁇ Fth” is satisfied, the first discharge is stopped. It can also be. It is also possible to monitor both V2 and ⁇ I2 / ⁇ t and suspend the first discharge when both “V2 ⁇ Vth” and “ ⁇ I2 / ⁇ t ⁇ Fth” are satisfied. can. In addition, it has the same effect as that of the first embodiment.
  • the discharge pause period DP is provided after the TDC.
  • the timing at which the gap flow velocity vg decreases is slightly delayed from the TDC, as described above. Therefore, in response to this, in the present embodiment, as shown in FIG. 12, the discharge pause period DP is provided in the expansion stroke.
  • the first discharge is generated so as to straddle the TDC. That is, the start time of the first discharge is immediately before the TDC, and the end time of the first discharge is immediately after the TDC. Then, a discharge pause period DP is provided in the expansion stroke, and then a second discharge is generated.
  • the expansion stroke can be set at the start time of the first discharge.
  • the discharge pause period DP is provided in the expansion stroke. Then, the gap flow velocity vg in the discharge period before and after the gap flow velocity vg in the discharge suspension period DP is set to be higher than the gap flow velocity vg.
  • Others are the same as those in the first embodiment.
  • the discharge pause period DP may be provided after the expansion stroke, that is, the TDC. That is, the timing when the gap flow velocity vg is low may be delayed from the TDC due to various factors such as the shape of the spark plug 1. Including such a case, by providing the discharge pause period DP at the timing when the gap flow velocity vg decreases, efficient combustion can be realized by the discharge before and after that. In addition, it has the same effect as that of the first embodiment.
  • the present disclosure is not limited to this.
  • the present disclosure is also applicable when the airflow flowing in the sub-combustion chamber 50 is, for example, a tumble flow or another flow method.
  • the plurality of discharge modes that generate two discharges in one cycle have been described, but the plurality of discharge modes may be configured to generate three or more discharges in one cycle.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Ignition Installations For Internal Combustion Engines (AREA)
  • Spark Plugs (AREA)
  • Combustion Methods Of Internal-Combustion Engines (AREA)
PCT/JP2021/026588 2020-08-21 2021-07-15 内燃機関の点火装置 Ceased WO2022038930A1 (ja)

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JP7224413B1 (ja) 2021-09-29 2023-02-17 三菱電機株式会社 内燃機関の制御装置

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JP6741513B2 (ja) 2016-08-04 2020-08-19 株式会社デンソー 内燃機関の点火装置
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JP2001280229A (ja) * 1999-10-21 2001-10-10 Denso Corp 火花点火装置
JP2004044404A (ja) * 2002-07-09 2004-02-12 Tokyo Gas Co Ltd 副室式内燃機関
US20090025670A1 (en) * 2007-07-25 2009-01-29 Gerald Filipek Spark to flame conversion unit, such as employed with an existing spark plug or heat source supplied glow plug for accomplishing more efficient piston combustion
JP2012041846A (ja) * 2010-08-18 2012-03-01 Daihatsu Motor Co Ltd 内燃機関の燃料噴射及び点火時期制御方法
JP2017103179A (ja) * 2015-12-04 2017-06-08 株式会社デンソー 点火プラグ
DE102017221517A1 (de) * 2017-11-30 2019-06-06 Robert Bosch Gmbh Zündkerze mit verlängertem Gehäuse und Masseelektrode an der Gehäuseinnenseite
JP2019190362A (ja) * 2018-04-25 2019-10-31 株式会社Ｓｏｋｅｎ 点火装置
JP2020159355A (ja) * 2019-03-21 2020-10-01 株式会社Ｓｏｋｅｎ 内燃機関用のスパークプラグ及びこれを備えた内燃機関

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JP2022035792A (ja) 2022-03-04
JP7468247B2 (ja) 2024-04-16

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