DELPHI AUTOMOTIVE SYSTEMS LUXEMBOURG SA

Patent Trials and Appeals Board

Oct 8, 2020

15036434 - (D) (P.T.A.B. Oct. 8, 2020)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
15/036,434 05/13/2016 FRANK LORENZ DP-321186-2 3347
152048 7590 10/08/2020
Delphi Technologies IP Limited
3000 University Drive
Delphi Technologies Legal Staff - M/C 483-300-450
Auburn Hills, MI 48326
EXAMINER
CHAN, WEI
ART UNIT PAPER NUMBER
2844
NOTIFICATION DATE DELIVERY MODE
10/08/2020 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
joshua.m.haines@delphi.com
us.patent@delphi.com
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte FRANK LORENZ, MARCO LOENARZ, and PETER WEYAND
____________

Appeal 2019-006075
Application 15/036,434
Technology Center 2800
____________

Before JEFFREY B. ROBERTSON, CHRISTOPHER C. KENNEDY, and
JANE E. INGLESE, Administrative Patent Judges.

INGLESE, Administrative Patent Judge.

DECISION ON APPEAL
Appellant1 requests our review under 35 U.S.C. § 134(a) of the
Examiner’s decision to finally reject claims 11–21.2 We have jurisdiction
over this appeal under 35 U.S.C. § 6(b).
We REVERSE.

1 We use the word “Appellant” to refer to the “applicant” as defined in 37
C.F.R. § 1.42. Appellant identifies Delphi Automotive Systems
Luxembourg SA as the real party in interest. Appeal Brief filed April 3,
2019 (“Appeal Br.”) at 3.
2 Final Office Action entered November 2, 2018 (“Final Act.”) at 1.
Appeal 2019-006075
Application 15/036,434

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CLAIMED SUBJECT MATTER
Appellant claims a method of controlling an ignition system. Appeal
Br. 4–7. Independent claims 11 and 21 illustrate the subject matter on
appeal, and read as follows:
11. A method of controlling an ignition system, said ignition
system including
a spark plug control unit adapted to control at least two
coil stages so as to successively energise and deenergise said at
least two coil stages to provide a current to a spark plug,
including two stages comprising a first transformer
including a first primary winding inductively coupled to a first
secondary winding; a second transformer including a second
primary winding inductively coupled to a second secondary
winding;
said spark plug control unit enabled to simultaneously
energize and deenergize said first primary winding and said
second primary winding by simultaneously switching on and
off two corresponding switches to sequentially energize and
deenergize said first primary winding and said second primary
winding by sequentially switching on and off both of said two
corresponding switches to maintain a continuous ignition fire,
and
includes a step-down converter stage located between
said spark plug control unit and said at least two coil stages,
said step-down converter including a switch and a diode,
said spark plug control unit being enabled to switch off
said switch,
wherein the method provides control to limit a secondary
current peak at the end of a Coupled Multi-Charge period,
comprising the steps of, at the end of the Coupled Multi-Charge
period:
i) switching off said switch which allows said primary
current to fall to zero; and
ii) toggling said two corresponding switches after
switching off said switch in step i) and while said switch
remains off.
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21. A method of controlling an ignition system, said ignition
system including
a spark plug control unit adapted to control at least two
coil stages so as to successively energise and deenergise said at
least two coil stages to provide a current to a spark plug,
including two stages comprising a first transformer
including a first primary winding inductively coupled to a first
secondary winding; a second transformer including a second
primary winding inductively coupled to a second secondary
winding;
said spark plug control unit enabled to simultaneously
energize and deenergize said first primary winding and said
second primary winding by simultaneously switching on and
off two corresponding switches to sequentially energize and
deenergize said first primary winding and said second primary
winding by sequentially switching on and off both of said two
corresponding switches to maintain a continuous ignition fire,
and
includes a step-down converter stage located between
said spark plug control unit and said at least two coil stages,
said step-down converter including a switch and a diode,
said spark plug control unit being enabled to switch off
said switch,
wherein the method provides control to limit a secondary
current peak at the end of a Coupled Multi-Charge period,
comprising the steps of, at the end of the Coupled Multi-Charge
period:
i) allowing said Coupled Multi-Charge period to expire;
ii) switching off said switch after step i) which allows
said primary current to fall to zero; and
iii) toggling said two corresponding switches after
switching off said switch in step ii) and while said switch
remains off.

Appeal Br. 20, 22–23 (Claims Appendix) (emphasis and spacing added).

Appeal 2019-006075
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REJECTION
The Examiner maintains the rejection of claims 11–21 under
35 U.S.C. § 103(a) as unpatentable over Lorenz et al. (EP 2 325 476 A1,
published May 25, 2011) in the Examiner’s Answer entered June 13, 2019
(“Ans.”).
FACTUAL FINDINGS AND ANALYSIS
Upon consideration of the evidence relied upon in this appeal and
each of Appellant’s contentions, we reverse the Examiner’s rejection of
claims 11–21 under 35 U.S.C. § 103(a), for reasons set forth in the Appeal
and Reply Briefs, and below.
Independent claims 11 and 21 both recite a method of controlling an
ignition system to provide a current to a spark plug, where the ignition
system includes, in part, at least two coil stages comprising a first
transformer including a first primary winding and a second transformer
including a second primary winding, a corresponding switch for each of the
first and second primary windings, and a step-down converter including a
switch. Claims 11 and 21 require the recited method to comprise, at the end
of a Coupled Multi-Charge period, switching off the step-down converter
switch to allow a primary current to fall to zero, and toggling the two
switches for the primary windings (“the two corresponding switches”) after
switching off the step-down converter switch while the step-down converter
switch remains off.
The Examiner finds that Lorenz discloses, and illustrates in Figure 1,
an ignition system that includes a first transformer including a first primary
winding, a second transformer including a second primary winding, a
corresponding switch for each of the first and second primary windings, and
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a step-down converter including a switch. Final Act. 6 (citing Lorenz Abst.;
Fig. 1). The Examiner finds that Figure 1 of Lorenz does not disclose the
method steps recited in claims 11 and 21 of at the end of the Coupled Multi-
Charge period, “i) switching off said switch which allows said primary
current to fall to zero; and ii) toggling said two corresponding switches after
switching off said switch in step i) and while said switch remains off.” Final
Act. 7 (emphasis omitted).
The Examiner finds, however, that other portions of Lorenz, including
Figures 2 to 5, disclose such steps. Final Act. 7–8 (citing Lorenz Abst.;
¶¶ 22, 23, 27, 28, 30, 34; Figs. 2–5). The Examiner concludes that it would
have been obvious to one of ordinary skill in the art to modify the ignition
system illustrated in Figure 1 of Lorenz to include the relied-upon steps from
Lorenz’s Figures 2 to 5, to produce a continuous ignition spark over a wide
area of burn voltage, and detect “burn voltage at spark plug by measuring
the gradient of secondary current as disclosed by Lorenz.” Final Act. 8–9
(citing Lorenz ¶ 5).
On the record before us, however, for reasons expressed by Appellant
(Appeal Br. 11–14, 18; Reply Br. 2–3) and discussed below, the Examiner
does not provide a sufficient factual basis to establish that Lorenz discloses
or would have suggested a method for controlling an ignition system that
involves switching off a step-down converter switch to allow a primary
current to fall to zero, and toggling two switches for primary windings (“the
two corresponding switches”) after switching off the step-down converter
switch while the step-down converter switch remains off, as required by
claims 11 and 21.
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Lorenz discloses a multi-charge ignition system that produces a
continuous ignition spark over a wide area of burn voltage, delivers an
adjustable energy to a spark plug, and allows a burning time of the ignition
fire to be chosen freely. Lorenz ¶ 5.
Lorenz discloses that the multi-charge ignition system comprises
ignition coils including primary windings L1, L3 wound on common core
K1 to form a first transformer, and secondary windings L2, L4 wound on
second common core K2 to form a second transformer. Lorenz ¶ 17; Fig. 1.
Lorenz discloses that one end of each primary winding L1, L3 is connected
to a corresponding switch Q1, Q2, and the other end of each primary
winding L1, L3 is connected to battery 15. Lorenz ¶¶ 18, 19; Fig. 1. Lorenz
discloses that battery 15 is coupled through ignition switch or transistor M1
to primary windings L1, L3. Lorenz ¶ 21; Fig. 1. Lorenz discloses that
control circuit 13 “is enabled to switch off switch M1 by means of a signal
FET,” and Lorenz discloses that control circuit 13 also controls the state of
switches Q1, Q2. Lorenz ¶¶ 20, 21.
Lorenz describes operation of the multi-charge ignition system as
involving six steps. Lorenz ¶¶ 22–30; Fig. 3. Lorenz discloses that the first
step involves switching switches M1, Q1, and Q2 on, which rapidly
increases a primary current and results in energy being stored in the
transformers; the second step involves switching off switches Q1 and Q2
when a high secondary voltage is induced, creating an ignition spark; the
third step involves switching Q1 on and Q2 off (or vice versa) so that
primary windings L1, L3 store energy while secondary windings L2, L4
deliver energy to the spark plug (or vice versa); and the fourth step involves
control circuit 13 switching transistor M1 off if the primary current increases
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over a pre-determined limit. Lorenz ¶¶ 22–28; Fig. 3. Lorenz discloses that
“[p]referably, transistor M1 will be permanently switched on and off to hold
the energy in the transformer on a constant level.” Lorenz ¶ 22. Lorenz
further explains that during the fourth step, “control signal FET is switched
off for a short time,” thus switching off transistor M1 for a short time.
Lorenz ¶ 28; see also ¶ 21(“[c]ontrol unit 13 is enabled to switch off switch
M1 by means of a signal FET.”). And Figure 3 of Lorenz shows that control
signal FET, which switches M1 off, is switched off for 50 microseconds if
the primary current exceeds a predetermined limit.
Lorenz discloses that the fifth step involves switching Q1 off and Q2
on (or vice versa), and the sixth step involves integrating steps 3 to 5 “by
sequentially switching on and off switches Q1 and Q2.” Lorenz ¶¶ 22, 23,
30. Lorenz explains that “[b]ecause of the alternating charging and
discharging of the two transformers the ignition system delivers a
continuous ignition fire.” Lorenz ¶ 23.
Lorenz thus discloses switching Q1 on and Q2 off (step 3), switching
control signal FET off, which switches M1 off, for 50 microseconds or “for
a short time,” if the primary current exceeds a predetermined limit (step 4),
switching Q1 off and Q2 on (step 5), and repeating these three steps (step 6)
in order to deliver a continuous ignition fire to the spark plug.
Appellant argues that Lorenz discloses switching M1 off temporarily
to limit the primary current when it exceeds a pre-determined value,
switching M1 back on again, and toggling Q1 and Q2 to hold the energy in
the transformers constant, in order to produce a continuous ignition spark.
Appeal Br. 11–13, 18. Appellant argues that Lorenz does not teach or
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suggest toggling Q1 and Q2 while switch M1 remains off as required by
claims 11 and 21. Id.
The Examiner responds to Appellant’s arguments in the Answer by
asserting that Figure 3 of Lorenz discloses that during steps 4 to 6 of
Lorenz’s method, the FET transistor “remains off.” Ans. 6, 11–12, 18, 28.
As discussed above, however, Lorenz discloses switching control
signal FET off, which switches M1 off, for 50 microseconds, or “for a short
time,” and Lorenz discloses that “[p]referably, transistor M1 will be
permanently switched on and off to hold the energy in the transformer on a
constant level.” Lorenz ¶¶ 22, 28; Fig. 3. Lorenz’s illustration in Figure 3
of switching FET off for 50 microseconds implicitly indicates that after 50
microseconds, FET is switched back on, thereby switching M1 back on.
Contrary to the Examiner’s assertion, Figure 3 of Lorenz, therefore, does not
show that FET, and switch M1, remain off during steps 4 to 6 of Lorenz’s
method.
On the record before us, the Examiner does not identify any disclosure
in Lorenz that teaches or would have suggested switching M1 off (the step-
down converter switch) to allow a primary current to fall to zero, and
toggling Q1 and Q2 (the two switches for the primary windings (“the two
corresponding switches”)) after switching M1 off (the step-down converter
switch) while M1 (the step-down converter switch) remains off, as required
by claims 11 and 21.
Nor does the Examiner provide an explanation grounded in sound
technical reasoning for why one of ordinary skill in the art would have
modified Lorenz’s method to involve such steps, in view of Lorenz’s
disclosure that the purpose of Lorenz’s multi-charge ignition system is to
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produce a continuous ignition spark, and disclosure that M1 preferably is
permanently switched on and off to hold the energy in the transformer on a
constant level. As Appellant argues, one of ordinary skill in the art
reasonably would have understood that M1 would need to be switched back
on after switching it off to provide a source of energy to the transformer to
hold the energy in the transformer on a constant level, allowing the
transformer to produce a continuous ignition spark, and if M1 were to
remain off, a source of energy would not exist for continuously producing an
ignition spark. Reply Br. 2–3.
We, accordingly, do not sustain the Examiner’s rejection of claims
11–21 under 35 U.S.C. § 103(a).
CONCLUSION

Claims

35 U.S.C. § Reference(s)/
Basis
Affirmed Reversed
11–21 103(a) Lorenz 11–21

REVERSED