(12) United States Patent
`Lepley
`
`USOO6701904B2
`(10) Patent No.:
`US 6,701,904 B2
`(45) Date of Patent:
`Mar. 9, 2004
`
`(54) CAPACITIVE DISCHARGE IGNITION
`SYSTEM WITH EXTENDED DURATION
`SPARK
`
`(75) Inventor: Joseph M. Lepley, Girard, OH (US)
`(73) Assignee: Altronic, Inc., Girard, OH (US)
`
`(*) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 100 days.
`(21) Appl. No.: 10/127,244
`9
`(22) Filed:
`Apr. 22, 2002
`(65)
`Prior Publication Data
`US 2002/0170547 A1 Nov. 21, 2002
`O
`O
`Related U.S. Application Data
`60
`(60) pyisional application No. 60/291.808, filed on May 17,
`
`(51) Int. Cl.................................................... F02P3/06
`(52) U.S. Cl. ........................ 123/604; 123/605; 123/620
`(58) Field of Search ................................. 123/604, 605,
`123/620
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`3,837,326. A
`9/1974 Kamiji
`
`3,893,438 A 7/1975 Diener
`3,973,544. A 8/1976 Suda
`4,149,508 A 4/1979 Kirk, Jr. et al.
`4,223,656. A
`9/1980 Hamley
`4.228,778 A 10/1980 Rabus et al.
`4,964,377. A 10/1990 Scarnera
`5,220,901 A 6/1993 Morita et al.
`FOREIGN PATENT DOCUMENTS
`
`2043166 A 10/1980 ............. FO2P/3/08
`GB
`* cited by examiner
`Primary Examiner Tony M. Argenbright
`Assistant Examiner Hyder Ali
`(74) Attorney, Agent, or Firm Webb Ziesenheim Logsdon
`Orkin & Hanson, P.C.
`(57)
`ABSTRACT
`A capacitive discharge ignition System for an internal com
`bustion engine comprises a converter transformer, an igni
`tion transformer, a first triggerable Switch S1, the primary
`winding of the ignition transformer and the Storage capacitor
`being connected in Series through the triggerable Switch, a
`Spark plug connected in Series with the Secondary winding
`of the ignition transformer, a Source of direct current and a
`Second triggerable Switch S2 connected in Series the primary
`of the converter transformer, and a circuit to control the first
`and Second triggerable Switches in Synchronism with the
`engine.
`
`5 Claims, 9 Drawing Sheets
`
`ENGINE
`
`CONTROL CIRCUIT
`
`
`
`
`
`M
`COILSEC SPARK
`GAP
`
`Exhibit 1007
`MOTORTECH v. Altronic - IPR2025-00398
`Page 1 of 14
`
`

`

`U.S. Patent
`
`Mar. 9, 2004
`
`Sheet 1 of 9
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`US 6,701,904 B2
`
`
`
`V7
`COLSEC SPARK
`GAP
`
`Exhibit 1007
`MOTORTECH v. Altronic - IPR2025-00398
`Page 2 of 14
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`

`

`U.S. Patent
`U.S. Patent
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`Mar. 9, 2004
`Mar.9, 2004
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`Sheet 2 of 9
`Sheet 2 of 9
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`MOTORTECH v. Altronic - IPR2025-00398
`Page 3 of 14
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`Exhibit 1007
`MOTORTECH v. Altronic - IPR2025-00398
`Page 3 of 14
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`U.S. Patent
`U.S. Patent
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`Mar. 9, 2004
`Mar.9, 2004
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`MOTORTECH v. Altronic - IPR2025-00398
`Page 4 of 14
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`Exhibit 1007
`MOTORTECH v. Altronic - IPR2025-00398
`Page 4 of 14
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`U.S. Patent
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`Mar. 9, 2004
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`Sheet 4 of 9
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`US 6,701,904 B2
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`Exhibit 1007
`MOTORTECH v. Altronic - IPR2025-00398
`Page 5 of 14
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`U.S. Patent
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`Mar. 9, 2004
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`Sheet 5 of 9
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`US 6,701,904 B2
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`Exhibit 1007
`MOTORTECH v. Altronic - IPR2025-00398
`Page 6 of 14
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`U.S. Patent
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`Mar. 9, 2004
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`Sheet 6 of 9
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`US 6,701,904 B2
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`Exhibit 1007
`MOTORTECH v. Altronic - IPR2025-00398
`Page 7 of 14
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`U.S. Patent
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`Mar. 9, 2004
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`MOTORTECH v. Altronic - IPR2025-00398
`Page 8 of 14
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`U.S. Patent
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`
`Mar. 9, 2004
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`MOTORTECH v. Altronic - IPR2025-00398
`Page 9 of 14
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`Exhibit 1007
`MOTORTECH v. Altronic - IPR2025-00398
`Page 9 of 14
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`

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`U.S. Patent
`U.S. Patent
`
`Mar. 9, 2004
`Mar.9, 2004
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`US 6,701,904 B2
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`MOTORTECH v. Altronic - IPR2025-00398
`Page 10 of 14
`
`Exhibit 1007
`MOTORTECH v. Altronic - IPR2025-00398
`Page 10 of 14
`
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`

`

`US 6,701,904 B2
`
`1
`CAPACTIVE DISCHARGE IGNITION
`SYSTEM WITH EXTENDED DURATION
`SPARK
`
`15
`
`25
`
`35
`
`CROSS REFERENCE TO RELATED
`APPLICATION
`This application claims priority to U.S. Provisional Patent
`Application Serial No. 60/291,808, filed May 17, 2001.
`BACKGROUND OF THE INVENTION
`It is an object, according to the present invention, to
`provide a capacitive discharge ignition System capable of
`generating an arc discharge between the Spark plug elec
`trodes with a duration three to six times longer than typical
`for the type of ignition coil in use.
`It is a further object, according to the present invention, to
`be able to adjustably and selectively modify or disable the
`extended duration Spark to obtain the best possible Spark
`plug life.
`When engine operation conditions require Spark durations
`previously unavailable from capacitive discharge ignitions,
`the extended spark can be enabled. This allows the use of a
`capacitive Spark ignition System where inductive-type igni
`tion Systems were the only practical choice.
`SUMMARY OF THE INVENTION
`Briefly, according to the present invention, there is pro
`vided a capacitive discharge (CD) ignition System for an
`internal combustion engine. The ignition System comprises
`a storage capacitor and diode in Series there with, a converter
`transformer having primary and Secondary windings, the
`Secondary winding thereof connected in Series with the
`Storage capacitor and diode, an ignition transformer having
`primary and Secondary windings, a first triggerable Switch,
`the primary winding of the ignition transformer and the
`Storage capacitor being connected in Series through the first
`triggerable Switch, a Spark plug connected in Series with the
`Secondary winding of the ignition transformer, a Source of
`40
`direct current, and a Second triggerable Switch connected in
`Series with the primary of the converter transformer. A
`circuit is provided to control the first and Second triggerable
`Switches in Synchronism with the engine Such that while the
`first Switch is open, the Second Switch is closed for a period
`to Store energy in the converter transformer and then opened
`to transfer energy to the Storage capacitor followed by again
`closing of the second Switch. The first Switch is closed to
`discharge the Storage capacitor to the primary of the ignition
`coil. The Second Switch is reopened to transfer energy Stored
`in the converter transformer to the primary of the ignition
`transformer to prolong the current in the Secondary of the
`ignition transformer. The number of times N the second
`Switch is reopened and closed and the time period T for
`which the Second Switch remains closed is controlled to
`control the duration and amplitude of the extended arc
`Current.
`
`45
`
`50
`
`55
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`Further features and other objects and advantages will
`become clear from the following detailed description made
`with reference to the drawings in which:
`FIG. 1 is a Schematic of the circuit configuration accord
`ing to the present invention;
`FIG. 2 shows Standard capacitive discharge circuit wave
`forms at 4 kV breakdown voltage providing a 500 micro
`Second Spark,
`
`60
`
`65
`
`2
`FIG. 3 shows Standard capacitive discharge circuit wave
`forms at 19 kV breakdown voltage providing a 380 micro
`Second Spark,
`FIG. 4 shows extended capacitive discharge circuit
`waveforms, according to the present invention, at 5 kV
`breakdown Voltage providing a 1,920 microSecond Spark;
`FIG. 5 shows extended capacitive discharge circuit
`waveforms, according to the present invention, at 19 kV
`breakdown Voltage providing a 1,920 microSecond Spark;
`FIG. 6 shows extended capacitive discharge circuit
`waveforms, according to the present invention, with eight
`extension pulses;
`FIG. 7 shows extended capacitive discharge circuit
`waveforms, according to the present invention, with twelve
`extension pulses;
`FIG. 8 shows extended capacitive discharge circuit
`waveforms, according to the present invention, with Short
`duration extension pulses and with low arc current; and
`FIG. 9 shows extended capacitive discharge circuit
`waveforms, according to the present invention, with long
`duration extension pulses and with higher arc current.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`Referring now to FIG. 1, a transformer TR1 has a primary
`winding and a Secondary winding. The primary winding of
`the first transformer TR1 is connected to a source of DC
`Voltage, e.g., a battery, via a Switch S2. A Storage capacitor
`C1 is positioned in parallel with the Secondary winding of
`transformer TR1. A diode D1 is positioned between the
`Secondary winding of the transformer TR1 and the Storage
`capacitor C1. The diode D1 is oriented to block charging of
`capacitor C1 with charging current -Is from the Sec
`ondary winding when the Switch S2 is closed and primary
`current It flows from the battery through the primary
`winding of the transformer TR1. A plurality of series con
`nected diodes D2 is connected in parallel with Storage
`capacitor C1. The diodes D2 are oriented to block a current
`I-A from Storage capacitor C1 from flowing therethrough.
`Connected in parallel with diodes D2 is a primary Side of an
`ignition coil. Connected between the primary Side of the
`ignition coil and the diodes D2 is a Switch S1. The ignition
`coil has a Secondary Side connected to a Spark gap, prefer
`ably the gap of a Spark plug.
`When Switch S1 opens, i.e., prior to an ignition event, the
`Switch S2 is closed and primary current It is allowed to
`flow into the primary winding of the transformer TR1. The
`phasing of the windings of the transformer TR1 is selected
`So that diode D1 blocks Secondary current -Is, from
`flowing through the Secondary winding of the first trans
`former TR1. When sufficient energy is stored in the primary
`of the first transformer TR1, Switch S2 is opened and energy
`from the collapsing magnetic field across the Secondary
`winding of the first transformer TR1 causes secondary
`current Is to flow through diode D1 and charge Storage
`capacitor C1.
`When it is time to provide a spark, Switch S1 is closed and
`the Voltage acroSS Storage capacitor C1 is impressed acroSS
`the primary Side of the ignition coil. After a delay due to coil
`inductance, current I
`begins to flow through the primary
`Side of the ignition coil. The Voltage impressed across the
`primary Side of the ignition coil causes a Voltage to develop
`on the Secondary Side of the ignition coil proportional to the
`turns ratio of the ignition coil. When the Secondary Voltage
`increases to a value Sufficient to cause a Spark discharge
`
`Exhibit 1007
`MOTORTECH v. Altronic - IPR2025-00398
`Page 11 of 14
`
`

`

`US 6,701,904 B2
`
`15
`
`3
`acroSS the Spark gap, coil Secondary current Ios, begins
`to flow. While the ignition coil secondary current is flowing,
`the Switch S2 is closed and current It flows through the
`primary of the first transformer TR1. The ignition coil
`Secondary current Ilos decreases with decreasing cur
`rent IAP from Storage capacitor C1.
`At an appropriate time before the Secondary current has
`decreased Sufficiently to extinguish the Spark discharge
`acroSS the Spark gap, the Switch S2 is opened and trans
`former TR1 secondary current Is, is developed which
`flows through the ignition coil primary. Hence, at this time,
`the current through the ignition coil primary I
`is the
`Sum of the transformer TR1 Secondary current Is, and
`the current IA from the Storage capacitor C1. The addition
`at the appropriate time of the Secondary current Is from
`the secondary coil of the transformer TR1 enables the
`duration of the Spark discharge acroSS the Spark gap to be
`extended. Moreover, the inductance of the Secondary coil of
`the transformer TR1 is connected in series with the induc
`tance of the primary coil of the ignition coil. Hence, the
`inductance of the circuit Supplying the current IP in
`the primary Side of the ignition coil increases with the
`addition of current Is from the Secondary winding of the
`first transformer TR1. This increase in inductance in com
`bination with the Secondary current Is, provided by the
`25
`transformer TR1 increases the arc duration in excess of the
`Sum of the capacitor current IA or the Secondary current
`Its of the transformer TR1 alone.
`The Switch S2 can be opened and closed a number of
`times N to prolong the spark current as shown in FIGS. 49.
`FIG. 2 illustrates the operation of the circuit according to
`the prior art. ASSume the capacitor C1 has been charged,
`Switches S1 and S2 are both open (non-conducting). In
`response to a trigger pulse, Switch S1 is closed (conducting).
`This results in a rush of current from the capacitor C1 to the
`primary of the ignition transformer. The Spike in Voltage
`across the primary of about 180 volts is illustrated by the
`middle trace of FIG. 2. This is reflected in the voltage spike
`to cause breakdown in the Spark gap illustrated in the top
`trace of FIG. 2. The breakdown voltage in the coil secondary
`in this instance is approximately 4 kV. The Spark duration is
`approximately 500 microseconds. The bottom trace illus
`trates the control Signal applied to the Switch S2 to close the
`Switch to permit recharging of capacitor C1. It should be
`understood that switch S1 had previously been opened.
`FIG. 3 is similar to FIG.2 except for a different spark gap
`condition, wherein the breakdown voltage acroSS the Sec
`ondary of the ignition coil is approximately 19 kV. This
`results in a Spark of reduced duration of 380 microSeconds.
`Hence, according to the prior art, the Spark duration is
`related to the breakdown voltage which is a characteristic of
`the Spark gap condition.
`FIG. 4 illustrates the operation of a circuit according to
`the present invention. After the initial closing of Switch S1
`and following breakdown in the Spark gap, the Switch S2 is
`repeatedly opened and closed as illustrated in the bottom
`trace of FIG. 4. In this instance, the Switch is opened and
`closed twelve (12) times over a period of 1,520 microsec
`onds. This causes the primary of the ignition coil to be
`reenergized as many times and the duration of the Spark to
`be extended to 1,920 microseconds.
`FIG. 5 illustrates the operation of a circuit according to
`the present invention much the same as FIG. 4. However, the
`Spark gap conditions were adjusted to increase the break
`down voltage in the primary of the ignition coil to 19 kV.
`The duration of the Spark, however, remains the same at
`
`35
`
`4
`1,920 microSeconds. Unlike the circuit operating according
`to the prior art procedures, the Spark duration is not tied to
`the Spark gap conditions.
`FIG. 6 illustrates that the spark duration can be controlled
`by controlling the number of reenergizing pulses Supplied to
`the capacitor C1. In this case, the Switch S2 is closed and
`opened eight (8) times over a period of 1,040 microSeconds
`and the Spark duration was extended to 1,440 microSeconds.
`FIG. 7 illustrates the voltage across capacitor C1 during
`operation according to the present invention, wherein after
`breakdown, the switch S2 is closed and opened twelve (12)
`times over 1,440 microSeconds. Note that the charge on the
`capacitor C1 is approximately 170 volts prior to close of the
`Switch S1. With each opening and closing, the capacitor is
`recharged to about 30 volts.
`FIGS. 8 and 9 illustrate the current in the ignition sec
`ondary (middle trace) as recorded. The difference between
`the conditions during which FIGS. 8 and 9 were recorded is
`the width of the time the Switch S2 was closed prior to
`reopening during the recharging period. The middle trace
`reflects ignition coil Secondary current. Due to a Serious
`baseline drift, the trace requires Some interpretation. In
`theory, the current never goes negative. In the test illustrated
`in both FIGS. 8 and 9, twelve equally spaced reenergizing
`pulses are used to extend the Spark duration. The pulses
`permitting current to flow in the primary of the converter
`transformer are wider for the test illustrated in FIG. 9 than
`in FIG. 8. The current peaks with the narrower energizing
`pulses are about 8 milliamps whereas with the wider ener
`gizing pulse, the current peaks are at about 40 milliamps.
`FIGS. 4 and 5 illustrate that with applicants invention,
`the Spark duration is not dependent on the conditions of the
`spark gap. FIGS. 6 and 7 illustrate that the duration of the
`Spark may be controlled by controlling the number of
`reenergizing pulses. FIGS. 8 and 9 illustrate that the current
`during the extended Spark duration can be controlled by
`controlling the width of the reenergizing pulses.
`Having thus described my invention in the detail and
`particularity required by the Patent Laws, what is desired
`protected by Letters Patent is set forth in the following
`claims.
`The invention claimed is:
`1. A capacitive discharge ignition System for an internal
`combustion engine comprising:
`a storage capacitor and diode in Series there with;
`a converter transformer having primary and Secondary
`windings, the Secondary winding thereof connected in
`Series with the Storage capacitor and diode,
`an ignition transformer having primary and Secondary
`windings,
`a first triggerable Switch(S1) the primary winding of the
`ignition transformer and the Storage capacitor being
`connected in Series through the triggerable Switch; a
`Spark plug connected in Series with the Secondary
`winding of the ignition transformer; a Source of direct
`current and a Second triggerable Switch(S2) connected
`in Series with the primary of the converter transformer;
`and
`control circuit for the first and Second triggerable Switches
`operating in Synchronism with the engine Such that
`while the first Switch is opened, the second Switch is
`closed for a period of time to Store energy in the
`converter transformer and then opened to transfer that
`energy to the Storage capacitor followed by the closing
`of the first Switch to discharge the Storage capacitor into
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`Exhibit 1007
`MOTORTECH v. Altronic - IPR2025-00398
`Page 12 of 14
`
`

`

`US 6,701,904 B2
`
`S
`the primary of the ignition transformer and while the
`first Switch remains closed, the Second Switch is again
`closed and then opened to transfer the energy Stored in
`the converter transformer to the ignition transformer
`primary to prolong the current flow in the Secondary
`winding of the ignition transformer.
`2. A device according to claim 1, wherein the control
`circuit for the triggerable Switches enables the Second Switch
`to be opened and closed a variable number of times while the
`first Switch remains closed during each firing event to
`control the arc duration of the Spark.
`3. A device according to claim 1, wherein the control
`circuit for the triggerable Switches enables the time period
`for which the second Switch remains closed before each
`iteration of it then being opened while the first Switch
`
`6
`remains closed to be a variable (T) used to control the
`amplitude of the extended arc current of the Spark.
`4. A device according to claim 1, 2, or 3, wherein the
`control circuit for the triggerable Switches enables the dura
`tion and amplitude of the extended arc current of the Spark
`to be controlled independently of the initial breakdown
`Voltage required to initiate the Spark.
`5. A device according to claim 1, wherein the control
`circuit for the triggerable Switches enables the Second trig
`gerable Switch is to be closed and opened at Spaced intervals
`and the ratio of closed time to open time to be controlled to
`control the current during the prolonged Spark.
`
`Exhibit 1007
`MOTORTECH v. Altronic - IPR2025-00398
`Page 13 of 14
`
`

`

`UNITED STATES PATENT AND TRADEMARK OFFICE
`CERTIFICATE OF CORRECTION
`
`PATENT NO. : 6,701,904 B2
`DATED
`: March 9, 2004
`INVENTOR(S) : Joseph M. Lepley
`
`Page 1 of 1
`
`It is certified that error appears in the above-identified patent and that said Letters Patent is
`hereby corrected as shown below:
`
`Column 4
`Line 53, “(S1) should read -- (S1), --.
`
`Column 6
`Line 11, “is to be' Should read -- to be --.
`
`Signed and Sealed this
`
`Twenty-seventh Day of July, 2004
`
`WDJ
`
`JON W. DUDAS
`Acting Director of the United States Patent and Trademark Office
`
`Exhibit 1007
`MOTORTECH v. Altronic - IPR2025-00398
`Page 14 of 14
`
`