US 10374529

I'll search for authoritative information on this specific patent number.

Let me verify whether any Federal Circuit 2026 appeal specifically involves this patent.

US Patent 10,374,529 — Analyst Summary

Search scope note: I searched public patent databases (Google Patents, Justia, USPTO-adjacent records), litigation trackers, PTAB dockets, and Federal Circuit sources for the exact number 10,374,529. I did not find any Federal Circuit (CAFC) docket, appeal, or opinion in 2026 naming this patent. I also flag a date discrepancy: the prompt states the current date is April 26, 2026, but several sources I retrieved are dated June–July 2026 (and the system timestamp is 2026-09-30). I report the records as retrieved rather than reconciling them.

Bibliographic data (as retrieved)

Prosecution/ownership chain (as listed by Google Patents — note the dates appear out of order in the record): GE → GE Intellectual Property Licensing, LLC (2025‑03‑26) → Dolby Intellectual Property Licensing, LLC (2025‑03‑26, change of name) → Edison Innovations, LLC (2025‑02‑20, assignment of assignor's interest) → Bunker Hill Technologies, LLC (2026‑04‑09, quitclaim assignment). I cannot independently verify this chain; treat it as reported, not confirmed.

Family: This is a continuation of Application 14/094,086 (now US 9,800,182). Related family members include US 10,291,158, US 10,673,358, US 11,374,508, CN 103847530 B, EP 2738036 A3, and JP 6334147 B2 — all sharing the "Electric drive system and energy management method" title.

Abstract (verbatim)

An electric drive system includes an energy storage system (ESS), a power conversion system, and an alternating current (AC) traction system. The ESS provides or receives electric power. The ESS includes a first energy storage unit and a second energy storage unit. The power conversion system is electrically coupled to the ESS for converting an input power to an output power. The AC traction system is electrically coupled to the power conversion system for converting the output power of the power conversion system to mechanical torques. The AC traction system includes a first AC drive device and a second AC drive device. An energy management system (EMS) is in electrical communication with the ESS, the AC traction system, and the power conversion system for providing control signals.

Independent claims in plain language

Claim 1 — "Drive system for a vehicle." A vehicle drivetrain with: (a) an energy storage system; (b) two electric motor/generators, both connected to the ESS; (c) a transmission device connected to the first motor/generator; (d) a power split device (built from one or more planetary gear sets) connected to the transmission device and to the second motor/generator; and (e) a load (e.g., the drive wheels) connected to the first motor/generator through the transmission and to the second motor/generator through the power split device. The key functional limitation: in a first mode, only the first motor/generator acts as a motor to drive the vehicle (used when cruising); in a second mode, both motor/generators act as motors (used when accelerating).

Claim 12 — "Electric drive system for a vehicle." The same architecture, but with the inverters expressly recited (a first inverter between the ESS and the first AC motor/generator; a second inverter between the ESS and the second AC motor/generator) and with both machines characterized as AC. The mode logic is parallel to claim 1, except the second mode (both machines motoring) is triggered when the vehicle is accelerating or in an uphill mode.

Claim 20 — "Drive system for a vehicle." Textually the same as claim 1 except the mode-selection trigger: the first mode is selected when cruising, and the second mode is selected when the vehicle is in an uphill mode (rather than accelerating).

Notable dependent claims: EMS in communication with the ESS and motors (2, 13); DC power conversion device between ESS and motors/inverters (3, 14, 19); ESS having first and second energy storage units (4, 15); separate first/second power conversion devices (5); battery + ultra-capacitor combination (6); induction motor paired with a permanent-magnet motor (8, 16); pre-charging switching device, optionally unidirectional (9, 10, 17); and the second motor/generator operated as a generator in the first mode (11, 18).

Technical bottom line: The granted '529 claims are narrower than the original parent's ESS/power-conversion/AC-traction claims — they are directed to a dual-motor, power-split (planetary) hybrid/BEV drivetrain whose control switches between one-motor cruising and two-motor acceleration/uphill operation.

Litigation and post-grant activity (as retrieved)

• District court: Bunker Hill Technologies, LLC v. Toyota Motor Corporation et al, Civil Action 2:25‑cv‑01133, E.D. Tex. (Judge Gilstrap), filed November 18, 2025. The asserted patent list includes 10,374,529, along with 10,291,158, 10,442,296, 10,549,648, 11,374,508, 8,030,884, 8,086,364, 8,326,467, and 9,914,365. Sources: Stanford NPE litigation database (https://npe.law.stanford.edu/case/[308840](/patent/308840)) and the Google Patents litigation link to the E.D. Tex. case.
• PTAB: Toyota Motor Corporation v. Bunker Hill Technologies, LLC, IPR2026‑00333, filed April 7, 2026. Careful reading of the docket shows Petitioner Exhibit 1001 is U.S. Patent No. 11,374,508 — i.e., that petition targets the '508 family member, not the '529. The '529 appears in that docket only as Patent Owner Exhibit 2005 (its prosecution history). So I found no IPR petition specifically challenging 10,374,529.
• Unified Patents has published an invalidity chart captioned for US 10,374,529 (https://www.unifiedpatents.com/s/BunkerHill_US10374529_invalidity-chart.pdf), citing references such as US 2012/0019172 A1 and US 2011/0227534 A1 against the claim elements.
• CAFC 2026: No appeal or docket specifically involving 10,374,529 surfaced. The 2026 Federal Circuit results returned were unrelated matters (e.g., the Spero v. Mercedes-Benz/Volkswagen appeals involving U.S. Patent Nos. 10,894,503 and 11,208,029).

Uncertainty flags

• Assignee record: Multiple assignment entries with non-chronological dates; the "Current Assignee" of Bunker Hill Technologies LLC is what the database lists, but I have not verified the underlying USPTO assignment records.
• CAFC: I can state only that my searches did not return a 2026 Federal Circuit docket for this patent — absence of a search hit is not proof that no appeal exists, particularly for very recent filings not yet indexed.
• Date inconsistency: Sources post-dating the stated current date were retrieved and are reported as-is; if the operative date is truly April 26, 2026, the June/July 2026 materials may be mis-dated by the source or the retrieval metadata.

I'll research litigation involving US 10,374,529. Let me start with targeted searches.

I found a lead. Let me dig deeper on the specific case and check for additional defendants/cases.

Let me check whether '529 was asserted in the Ford/Nissan suits and whether there are PTAB challenges on the '529 patent specifically.

Summary: litigation involving US 10,374,529

Bottom line: I found one district-court litigation in which US 10,374,529 ("the '529 patent") was identified as an asserted patent — Bunker Hill Technologies, LLC v. Toyota Motor Corp. et al., No. 2:25-cv-01133 (E.D. Tex.). It is pending; no outcome yet. No other case, and no PTAB/IPR proceeding naming the '529 patent as the challenged patent, was found.

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Case 1 — BUNKER HILL TECHNOLOGIES, LLC v. Toyota Motor Corporation, Toyota Motor North America, Inc., and Toyota Motor Sales, U.S.A., Inc.

Sources: Stanford NPE Litigation Database (case 308840) listing the '529 patent among those asserted — https://npe.law.stanford.edu/case/308840 ; Unified Patents litigation portal — https://portal.unifiedpatents.com/litigation/Texas%20Eastern%20District%20Court/case/2%3A25-cv-01133 ; Docket (Justia) — https://dockets.justia.com/docket/texas/txedce/2:2025cv01133/[241855](/patent/241855)

Procedural history / current status (from the docket retrieved 5/5/2026):

• 12/10/2025 — Unopposed motion for extension of time to answer (granted 12/16/2025).
• 3/10/2026 — Toyota entities filed their Answer and Counterclaim against Bunker Hill.
• 3/11/2026 – 3/30/2026 — pro hac vice appearances (e.g., Eric W. Schweibenz); Bunker Hill filed its Answer to the counterclaim on 3/30/2026.
• 4/29–30/2026 — Order vacating referral to the magistrate judge (case retained by Judge Schroeder).
• 5/5/2026 — Order setting a scheduling conference for 6/2/2026.
• No claim construction, summary judgment, trial date, or disposition found. No injunction, damages award, settlement, or dismissal has been reported.

Technical theory of the case (for context): the complaint targets Toyota's "Hybrid Synergy Drive" powertrain — two motor-generators (MG1/MG2), a power control unit, and a planetary gear set serving as the "power split device" — plus charging and energy-management features. This maps directly onto the '529 claims, which recite an ESS, first and second electric motor/generators, a transmission device, and a power split device comprising one or more planetary sets, with a first cruise mode using only the first motor/generator and a second accelerating/uphill mode using both. Source: complaint analysis, https://ai-lab.exparte.com/case/dct/txed/2:25-cv-01133/doc/analysis/1

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Related proceedings in the same patent family (same 2012-12-03 priority; NOT challenges to the '529 patent itself)

These are worth flagging because they bear on the '529 patent's validity exposure, but none of them names US 10,374,529 as the challenged patent — I am listing them only to avoid confusion with the '529 patent:

• Toyota Motor Corp. v. Bunker Hill Technologies, LLC, IPR2026-00250 (PTAB, filed 2/3/2026) — challenges US 10,549,648. Bunker Hill filed a request for discretionary denial (4/8/2026). https://sandbox.docketalarm.com/cases/PTAB/IPR2026-00250/
• Toyota Motor Corp. v. Bunker Hill Technologies, LLC, IPR2026-00333 (PTAB, filed 4/7/2026) — challenges US 11,374,508. Notably, Patent Owner Exhibit 2005 is the prosecution history of US 10,374,529, and the '508 patent is a continuation in the same family as the '529 patent. https://sandbox.docketalarm.com/cases/PTAB/IPR2026-00333/
• Unified Patents ex parte reexamination, control no. 90/016,093 — challenges US 9,914,365; granted 6/1/2026 on all challenged claims. This is the proceeding that produced the widely reported "Bunker Hill EV patent" challenge. https://unifiedpatents.squarespace.com/insights/2026/6/2/dominion-harbor-entity-bunker-hill-ev-battery-patent-challenge-granted
• Unified Patents prior-art/invalidity chart directed at the '529 patent — a chart captioned "BunkerHill_US10374529_invalidity-chart.pdf" was published as part of Unified's campaign against the Bunker Hill portfolio. As of the material I found, this is a published chart, not a filed IPR. https://www.unifiedpatents.com/s/BunkerHill_US10374529_invalidity-chart.pdf

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Cases where the '529 patent does NOT appear (checked to rule out)

• Bunker Hill Technologies, LLC v. Ford Motor Co., No. 2:25-cv-01116 (E.D. Tex., filed 11/10/2025; terminated/dismissed 2/11/2026 after a joint motion to dismiss following settlement). The patents identified in the available records for this case are the '023, '582, '439, '884, '365, '121, '296, '857, '467, and '668 patents — the '529 patent is not among them. https://cdn.pacermonitor.com/public/case/61108837/
• Bunker Hill Technologies, LLC v. Nissan Motor Co. Ltd., No. 2:26-cv-00231 (E.D. Tex., filed 3/19/2026; open). Patents identified: the '467, '364, '857, and '668 patents (plus two more not shown) — the '529 patent is not among the identified patents. https://portal.unifiedpatents.com/litigation/Texas%20Eastern%20District%20Court/case/2%3A26-cv-00231

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Caveats I want to be explicit about

1. I could not access PACER directly, and the Ford and Nissan complaint patent lists above come from secondary databases that displayed truncated ("+6 more," "+2 more") patent lists. I verified the '529 patent's presence in the Toyota case from the Stanford NPE database's explicit patent list. I could not rule out with absolute certainty that '529 appears in a truncated portion of the Ford or Nissan lists, though nothing in the sources I retrieved supports that.
2. No appellate (CAFC) activity for the '529 patent was found. The Toyota case has not reached judgment, so there is nothing to appeal.
3. No earlier litigation involving the '529 patent itself appears in the record; the Google Patents "family has litigation" flag for the '529 patent points to the same Texas case. Earlier GE-era assertion activity against the parent US 9,800,182 was not found.
4. Date discrepancy: your prompt states the current date is April 26, 2026, but the source material I retrieved includes events dated after that (docket retrieved May 5, 2026; Unified Patents insight dated June 1–2, 2026; PTAB entries through June 10, 2026). I have reported those later events as retrieved rather than suppressing them, and you may want to reconcile the date before relying on the above.
5. Ownership note: per Google Patents, current assignee is Bunker Hill Technologies LLC, following a chain General Electric → GE Intellectual Property Licensing → Dolby Intellectual Property Licensing → Edison Innovations → Bunker Hill (quitclaim, recorded 2026-04-09). Assertions by Bunker Hill against Ford, Toyota, and Nissan are consistent with that chain.

I'll verify the "no PTAB activity" default with targeted searches before writing the report.

A hit surfaced that I need to run down — an IPR naming Bunker Hill Technologies (the current assignee) with 10,374,529 in the exhibit list. Let me verify.

Key finding: the Toyota IPR I found targets a different patent (’508), not ’529. Let me confirm whether any proceeding names ’529 itself and map the family-wide pattern.

Proceedings overview

Zero AIA trial proceedings are on file against U.S. Patent No. 10,374,529 ("the ’529 patent"). The structured USPTO Open Data Portal block in this prompt returns no IPR, PGR, or CBM for this patent, and my independent searches surfaced no petition naming the ’529 patent as the challenged patent. Breakdown by status is therefore 0 active / 0 invalidated / 0 sustained / 0 settled / 0 institution denials — meaning all 20 issued claims of ’529 remain UNTESTED at the PTAB.

The defensive posture this gives a defendant is not "the patent is hardened," and it is not "the claims are dead." It is: the ’529 patent is untouched by the Board but sits at the center of a multi-front NPE campaign, and Toyota's petitions against its sibling patents supply a ready-made invalidity roadmap that no one has yet fired at ’529 itself (see Strategic summary). Critically, because no Final Written Decision has ever issued on any ’529 claim, no § 315(e)(2) estoppel attaches to anyone, and a defendant's IPR options remain fully open — subject only to the § 315(b) one-year clock.

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Proceedings against the ’529 patent

None. No proceeding number exists to report, and I will not invent one.

Verification performed (log as of today, 2026-09-30):

Caveat, stated plainly: third-party aggregators lag the ODP. It is possible a very recently filed ’529 petition exists that is not yet indexed. I found no evidence of one, but absence of evidence here is not proof of absence.

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Related PTAB activity on the same patent family (NOT on ’529 — read the captions carefully)

These matter enormously to a ’529 defendant because the ’508 patent is a same-family continuation (both trace to the 2012-12-03 priority date; the ’508 patent appears in the US10374529 family listing as US16/866,028 → US11374508B2). Different patent number, near-identical claim scope.

IPR2026-00333 — Toyota Motor Corporation v. Bunker Hill Technologies, LLC

• Type: Inter Partes Review — challenged patent is U.S. 11,374,508 (the ’508 patent), not ’529
• Filed: 2026-04-07
• Status: Reported as "Terminated–Settled" with a termination date of 2026-08-11 by IP Verse; Docket Alarm's sandbox mirror still shows "Pending." Conflict flagged — treat the settlement as reported but not officially confirmed.
• Judge panel: Not public — "Pending Judge Assignment" per the AI-Lab mirror; no institution decision surfaced, so no panel of record
• Petition grounds: All 17 claims challenged (claims 1–17) —
  • Ground 1: § 102 anticipation of claims 1, 2, 4, 7, 8, 12, 13, 15 over Tsuzuki (JP 2010-036880)
  • Ground 2: § 103 over Tsuzuki in view of Reynolds (US 2014/0100726)
  • Ground 3: § 103 over Tsuzuki in view of Imai (JP 2010-221979)
  • Supporting exhibits included Zing (US 8,618,752), Ashtiani (US 2006/0098390), Satoru (JP 2001-218380), Ehsani's Modern Electric, Hybrid Electric, and Fuel Cell Vehicles, and the declaration of Prof. Mahdi Shahbakhti (2026-04-06)
  • Toyota mapped Tsuzuki's "second EV mode" (MG2 only, low speed/low accelerator) onto the claimed cruising mode and its "first EV mode" (both MGs) onto accelerating — the exact mode dichotomy recited in ’529 claims 1, 12, and 20
• Institution decision: None found. Patent Owner filed a discretionary-denial brief on 2026-06-10 (PO Paper 7) invoking § 314(a) and relying on PO Ex. 2002 (the parallel complaint), PO Ex. 2001 (Pridham declaration), and PO Exhibits 2004/2005/2006 — the prosecution histories of U.S. 9,800,182, 10,374,529, and 10,673,358. Note: ’529 appears here only as an exhibit, not as the challenged patent. Toyota filed a Sotera-style stipulation with the petition.
• Final Written Decision: None. Case reportedly terminated before any FWD.
• Settlement / termination: Reported settlement with 2026-08-11 termination date; terms not public (settlement agreements in IPR are typically confidential and filed under seal). I could not confirm whether this was part of a global resolution of the co-pending E.D. Tex. action.
• Appeal: None — no FWD means nothing appealable.
• Defensive value: Even though it isn't a ’529 case, it is the most useful document in this whole matter: Toyota's Tsuzuki/Imai/Reynolds mapping is a charted, expert-supported invalidity theory that translates almost verbatim onto ’529 claims 1, 12, and 20. If those claims are what you're accused of infringing, that petition is your starting draft.

IPR2026-00250 — Toyota Motor Corporation v. Bunker Hill Technologies, LLC

• Type: Inter Partes Review — challenged patent is U.S. 10,549,648 (the ’648 patent), a different Bunker Hill/Dominion Harbor asset, not ’529
• Filed: 2026-02-03
• Status: Reported as "Terminated–Settled," termination date 2026-08-12, per IP Verse; institution decision date reported as 2026-07-14
• Judge panel: Not public in the sources reviewed
• Petition grounds: Claims 1–20 challenged —
  • Ground 1: § 102 anticipation of claims 1, 4, 5, 7, 8, 16, 18–20 over Conlon (US 2009/0176610)
  • Ground 2: § 102 anticipation of claims 1, 2, 4–10, 12–20 over Ortmann (US 2013/0012347)
  • Ground 3: § 103 over Conlon in view of Reynolds (US 2014/0100726), plus an alternative Conlon-alone obviousness theory
  • Declaration of Dr. Mahdi Shahbakhti; a Sotera stipulation was filed 2026-02-12
• Institution decision: Reported 2026-07-14 (outcome not confirmed in the sources I could reach)
• Final Written Decision: None found. If institution issued on 2026-07-14 and the case terminated on 2026-08-12, that would be a post-institution settlement with no FWD — and therefore still no estoppel (see § 315(e)(2) below).
• Settlement / termination: Reported settled 2026-08-12; terms confidential
• Appeal: None
• Defensive value: Confirms Toyota was running a coordinated multi-patent PTAB campaign against the Bunker Hill portfolio, and that the campaign resolved by agreement in August 2026 without the Board ever reaching the merits.

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Strategic summary

Claim-level status of the ’529 patent. Every claim is UNTESTED: independent claims 1, 12, and 20, and all seventeen dependent claims (2–11, 13–19), stand exactly as granted on 2019-08-06. Nothing is canceled, nothing is confirmed by the Board, nothing has been narrowed by certificate. Contrast this with the family-level picture: Toyota attacked all 17 claims of the ’508 sibling and all 20 claims of the ’648 patent, and the ’529 patent's own prosecution history was pulled into IPR2026-00333 as Patent Owner's Exhibit 2005 — i.e., the art fight has circled the ’529 patent without ever landing on it.

Estoppel landscape. Because no Final Written Decision has ever issued on a ’529 claim, § 315(e)(2) estoppel is zero-sum. No petitioner, real party in interest, or privy is estopped from asserting any § 102/§ 103 ground against ’529 in district court or the ITC. Two caveats worth pricing in:

• The reported settlements of IPR2026-00250 and IPR2026-00333 likely carry contractual (not statutory) restrictions — e.g., a license, covenant not to sue, or agreement not to challenge validity again. Those bind the settling parties and their privies but are invisible to non-privies. If you are a different automaker (Nissan, Volvo/Polestar), you are not estopped by Toyota's deal.
• Toyota's own § 315(b) clock: the E.D. Tex. complaint in 2:25-cv-01133 was filed 2025-11-18, so any Toyota ’529 petition would have been due roughly 2026-11-18. Whether Toyota filed a ’529 petition before settling is the single most important unknown in this matter, and I could not resolve it from available sources.

Pattern signals. (1) Bunker Hill Technologies, LLC is an NPE and an entity of Dominion Harbor Enterprises, LLC, running a serial automotive campaign — Toyota (2:25-cv-01133, 2025-11-18), Ford (2:25-cv-01116, 2025-11-10, dismissed 2026-02-11 after a 2026-01-14 joint stay/notice of settlement), Nissan (2:26-cv-00230 and 2:26-cv-00231, 2026-03-19/20), and Volvo/Polestar (2:26-cv-00742, filed 2026). The ’529 patent is asserted in the Toyota action. (2) A defensive aggregator is present but not on this patent: Unified Patents filed an ex parte reexamination against Bunker Hill's U.S. 9,914,365 on 2026-03-27, which the CRU granted on 2026-06-01 finding substantial new questions of patentability on all challenged claims — and Unified has publicly published charted prior art specifically on the ’529 patent as part of its "weekly" campaign against the portfolio. That is a strong tell that a ’529 validity challenge is being prepared outside the courtroom. An ex parte reexam is not an AIA trial and does not appear in your ODP PTAB block; do not let it slip through your docket review. (3) Bunker Hill appears to have resolved its first two automaker campaigns (Ford, then Toyota) by settlement in the same window its IPRs were settling — a monetization-first, not merits-first, posture.

Ownership reminder. The ’529 patent has been passed through GE → GE Intellectual Property Licensing, LLC (2025-03-26) → Dolby Intellectual Property Licensing, LLC (2025-03-26, change of name) → Edison Innovations, LLC (2025-02-20) → Bunker Hill Technologies, LLC (quitclaim assignment recorded 2026-04-09). Anticipated expiration 2033-12-02, so roughly seven years of asserted life remain.

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Recommended next steps

1. State the negative plainly, and use it. There is no PTAB activity against the ’529 patent. If opposing counsel is telling your board that the patent "already survived IPR" or "is IPR-hardened," that is false — it has never been to the Board. Conversely, no claim is canceled, so nothing in the demand letter is unenforceable on that basis.
2. If you have been served with a ’529 complaint, diary § 315(b) immediately. Your petition deadline is one year from service of the first complaint alleging infringement of the patent. There is no FWD-driven estoppel on this patent to worry about — your grounds are all live.
3. Build the petition off Toyota's ’508 work. Retrieve the IPR2026-00333 petition and its Shahbakhti declaration and exhibits (Tsuzuki JP 2010-036880; Imai JP 2010-221979; Reynolds US 2014/0100726) via PTAB E2E or the Docket Alarm docket. Tsuzuki's "second EV mode = one motor at cruise / first EV mode = both motors under load" maps directly onto the mode limitations of ’529 claims 1, 12, and 20. Verify the record yourself before relying on third-party summaries, including mine.
4. Pull Unified's charted ’529 prior art. Unified published an "Identified Prior Art on U.S. Patent 10,374,529" chart: https://www.unifiedpatents.com/insights/tag/Dominion+Harbor. Free prior-art work product; treat it as a lead, not as a finished record.
5. Track the two reported settlements and the parallel litigations.
   • IPR2026-00250 (’648): terminated–settled 2026-08-12 (case details)
   • IPR2026-00333 (’508): terminated–settled 2026-08-11 (case details)
   • E.D. Tex. 2:25-cv-01133 (Toyota) was still active on the docket through 2026-05-05 (docket) — if the PTAB settlements were part of a global resolution, expect a dismissal order; if not, expect Toyota's ’529 petition to surface in the ODP in short order.
6. Re-run the ODP check before you rely on this memo. The docket-lag problem cuts both ways: a ’529 petition filed in, say, September 2026 would not yet be in the ingest that generated this report. Set an alert on the patent at PTAB E2E and re-verify ownership and status before any filing deadline.

Sourcing note / limitations. The "no proceedings" conclusion is grounded in the canonical USPTO ODP block supplied in this prompt and corroborated by the Google Patents record for the patent (https://patents.google.com/patent/US10374529/en), which shows only district-court litigation. The family-level IPR details come from third-party aggregators (IP Verse, Docket Alarm mirrors, AI-Lab/Ex Parte summaries) and Unified Patents' public blog, not from primary PTAB documents; the ’508 IPR's status is contradictory across aggregators ("Pending" vs. "Terminated–Settled"), no judge panel is public, and I found no Final Written Decision, no institution decision on the merits for IPR2026-00333, and no Federal Circuit appeal in any of these matters. Where I could not confirm, I have said so rather than filling the gap.

I'll research the assignment chain and litigation record before reconstructing the timeline.

Assignment & Ownership Reconstruction — US 10,374,529 B2

Scope note / limitation up front: I reconstructed this chain from Google Patents' legal-events feed for US 10,374,529, USPTO records as indexed there, federal court dockets, Unified Patents and Stanford NPE litigation databases, and issuer/press disclosures. I was not able to pull the Assignment Center record images directly, so reel/frame numbers and the correspondent-of-record attorney names are not verified in this report — I flag every field where that matters rather than guessing. Verification path is given in the Verdict section.

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Inventors

All five named inventors on the face of US 10,374,529 B2, and their status relative to the assignee:

Basis: the recorded 2017-03-10 assignment of assignors' interest to General Electric Company lists assignors "LIU, DONG; ZHOU, JIAN; XU, FEI; KANG, PENGJU; QIU, HAI" — i.e., all five inventors, no non-inventor assignors, no third-party co-owner.

Pattern assessment: The inventor-assignment event is unremarkable — a routine confirmatory assignment recorded two days after the 2017-03-08 continuation filing (the parent, US 14/094,086, was filed 2013-12-02 and issued as US 9,800,182 B2). There is no evidence in the record of the "all inventors depart within 12 months" pattern that often precedes a portfolio fire-sale. However, I could not verify individual inventor departure dates from GE (no PEDS/WARN/SEC data retrieved); treat that specific sub-signal as not determinable rather than negative. Notably, the inventors never appear as assignors in any post-2017 link — the entire downstream chain runs entity-to-entity, which is what you would expect once the portfolio became a corporate asset.

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Original assignee

General Electric Company (original assignee of record; Schenectady, NY / Boston, MA headquarters).

• Line of business: diversified industrial/manufacturing conglomerate — power generation, aviation, healthcare, and electrification. The patent itself (dual-ESS, dual-motor AC traction with a power-split device) is EV/powertrain research output of GE Global Research, not a GE product line.
• Product embodying the claims: No. GE did not commercialize a passenger EV or this dual-motor/dual-ESS traction architecture. GE does ship adjacent electrification hardware (GE Vernova), but I found no product mapping to claims 1/12/20.
• Current status: Operating, but structurally changed. GE completed its three-way separation (GE Aerospace, GE Vernova, GE HealthCare). The patent no longer resides with any GE entity — it left GE via the GE Licensing divestiture (see timeline). GE did not file bankruptcy; this was a solvent, negotiated $429M divestiture, not a Chapter 7/11 fire-sale.

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Assignment timeline

Recorded events attributable to this patent (Google Patents legal events; reel/frame not retrieved — see caveat). Note that recordation order ≠ execution order here, which is itself worth flagging.

1. Recorded 2017-03-10 (executed on/around 2017-03-08) — Reel/frame: not retrieved

• Conveyance: Assignment of Assignors' Interest
• Assignor: Dong Liu; Jian Zhou; Fei Xu; Pengju Kang; Hai Qiu (individual inventors)
• Assignee: General Electric Company
• Correspondent: not retrieved — Assignment Center record image not accessed.
• Context: Inventor-to-employer confirmatory assignment supporting the 2017 continuation filing.

2. Recorded 2025-03-26 — Reel/frame: not retrieved

• Conveyance: Assignment of Assignor's Interest
• Assignor: General Electric Company
• Assignee: GE Intellectual Property Licensing, LLC
• Correspondent: not retrieved.
• Context: Internal corporate restructuring — GE parks the portfolio in its IP-holding subsidiary ahead of the GE Licensing sale. No third party involved.

3. Recorded 2025-03-26 — Reel/frame: not retrieved

• Conveyance: Change of Name
• Assignor: GE Intellectual Property Licensing, LLC
• Assignee: Dolby Intellectual Property Licensing, LLC
• Correspondent: not retrieved.
• Context: Entity rename tied to Dolby Laboratories' acquisition of GE Licensing (closed September 2024; ~$429M for ~5,000 GE Licensing assets). Because this is recorded as a change of name, the Dolby acquisition appears to have been effected through the GE IP-holding entity itself rather than a fresh asset assignment.

4. Recorded 2025-02-20 — Reel/frame: not retrieved

• Conveyance: Assignment
• Assignor: Dolby Intellectual Property Licensing, LLC
• Assignee: Edison Innovations, LLC (subsidiary of Dominion Harbor Enterprises / Dominion Harbor Group, Dallas, TX)
• Correspondent: not retrieved.
• Context: Portfolio resale — Dolby "held them for sale" and sold ~2,500 of the GE-originated assets to Dominion Harbor's Edison Innovations; publicly announced 2025-02-19, one day before recordation. Recorded before links 2 and 3 even though it is downstream of both.

5. Recorded 2026-04-09 — Reel/frame: not retrieved

• Conveyance: Quitclaim Assignment
• Assignor: Edison Innovations LLC
• Assignee: Bunker Hill Technologies, LLC
• Correspondent: not retrieved. — highest-value field to fill in; see Verdict.
• Context: Intra-Dominion Harbor transfer to its assertion vehicle. Critically, the litigation came first: Bunker Hill sued Toyota as named plaintiff on 2025-11-18 (see next section), roughly five months before this quitclaim was recorded. Either the conveyance was executed pre-suit and recorded late, or the docket/complaint predates a clean standing record.

Assertion events (not assignments, listed for context):

• 2025-11-18 — Bunker Hill Technologies, LLC v. Toyota Motor Corporation, Toyota Motor North America, Inc., Toyota Motor Sales, U.S.A., Inc., No. 2:25-cv-01133 (E.D. Tex., Judge Robert W. Schroeder III). Nine asserted patents: US 8,030,884; 8,086,364; 8,326,467; 9,914,365; 10,291,158; 10,374,529; 10,442,296; 10,549,648; 11,374,508.
• 2026-03-19 — Bunker Hill Technologies LLC v. Nissan Motor Co. Ltd., No. 2:26-cv-00231 (E.D. Tex.), expressly related to 2:25-cv-01133.
• 2025-10-22 and 2025-11-07 — Unified Patents publishes claim-charted prior art against Bunker Hill-asserted EV patents, describing Bunker Hill as "an NPE and entity of Dominion Harbor Enterprises."

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Timeline diagram

timeline
    title Ownership of US 10374529
    2012 : Priority application filed in China
    2013 : US parent application filed
    2017 : Continuation filed by General Electric
         : Inventors assign rights to GE
    2019 : Patent US 10374529 issues
    2024 : Dolby buys GE Licensing
    2025 : GE unit renamed Dolby IP Licensing
         : Dolby sells 2500 assets to Edison Innovations
         : Bunker Hill sues Toyota in E D Texas
    2026 : Edison quitclaims patent to Bunker Hill
         : Bunker Hill sues Nissan

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NPE / troll-pattern signals

1. Shell-entity transfer — PRESENT.
The patent left an operating company (GE) and passed through a chain of non-operating holding/licensing entities: GE IP Licensing LLC → Dolby IP Licensing LLC → Edison Innovations LLC → Bunker Hill Technologies, LLC. Bunker Hill has no product; its only public description is Dominion Harbor's own site, which says it "is actively assembling a growing portfolio of patented technologies focused on connected vehicle solutions" (https://www.dominionharbor.com/portfolio) — a portfolio statement, not a product statement. Unified Patents describes Bunker Hill flatly as "an NPE and entity of Dominion Harbor Enterprises." Anchor records: the 2025-02-20 Dolby→Edison assignment and the 2026-04-09 Edison→Bunker Hill quitclaim. (Reel/frame not retrieved; entity identity and dates are the basis for the call.)

2. Known asserter in the chain — PRESENT.
Current assignee/plaintiff Bunker Hill Technologies, LLC and its parent Dominion Harbor Enterprises are high-frequency patent assertion entities surfaced by Unified Patents and listed as an NPE in the Stanford NPE litigation database (https://npe.law.stanford.edu/case/[308840](/patent/308840), which records NPE Status = "Non Practicing Entity" for the Toyota action). Bunker Hill is not on the specific enumerated list in the prompt (Acacia, Marathon, IV, IPNav, Wi-LAN/Mosaid, Vringo, Pendrell, etc.) — but the prompt's list is non-exhaustive and explicitly includes "any entity surfaced by Unified Patents or RPX as a high-frequency plaintiff," which Bunker Hill/Dominion Harbor satisfies. Unified Patents has publicly said it "plans to release charted prior art on Bunker Hill patents weekly until its assertion of invalid patents ceases" — i.e., Unified is treating this as an active NPE campaign.

3. Repeat correspondent across the chain — UNCLEAR (not verifiable here).
This is the one signal I cannot responsibly score, and it is the one you flagged as the most probative tell. I did not retrieve the correspondent-of-record attorney for any of the five recorded events; Google Patents' legal-events feed does not publish it and I did not obtain the Assignment Center images. Because the shell LLCs share a common parent (Dominion Harbor) at links 4–5, my working expectation is that the same recording attorney/firm appears on both the 2025-02-20 and 2026-04-09 records, and possibly on the 2025-03-26 GE-to-GE-IP-Licensing reorg. This should be confirmed directly before any filing. Do not treat a single appearance as a finding — the signal is recurrence across links.

4. Cascading transfers — PRESENT.
Four recorded post-issuance assignments land inside a ~13-month window (2025-02-20, 2025-03-26, 2025-03-26, 2026-04-09), and three distinct downstream owners hold the asset in under 18 months (Dolby IP Licensing → Edison Innovations → Bunker Hill). Mitigating nuance: links 2–3 are a single corporate divestiture wave (GE → GE IP Licensing → Dolby) and links 4–5 are an intra-Dominion Harbor move, so this is two transactions, not five unrelated hops. The cascading is real but is better characterized as a bulk-portfolio carve-out feeding an assertion vehicle than as classic hard-to-follow laundering.

5. Pre-litigation transfer — UNCLEAR.
On the face of the public record the sequencing is inverted: the Edison→Bunker Hill quitclaim is recorded 2026-04-09, while the first suit naming this patent was filed 2025-11-18 — nearly five months earlier. That is not the classic "assignment within 6 months before the first suit" setup. The more likely explanation is that the conveyance was executed pre-suit and simply recorded late (Bunker Hill pleaded as owner from the November 2025 complaint onward). The upstream event — the 2025-02-20 Edison Innovations acquisition — is ~9 months before the first suit. Either way, note the standing/chain-of-title question is exactly the kind of thing Toyota's counterclaim (Dkt. 21, 2026-03-10) could probe.

6. Bankruptcy fire-sale — NOT PRESENT.
No GE bankruptcy. The GE Licensing sale was a solvent, negotiated $429M divestiture to Dolby Laboratories (closed Sept 2024), and Dolby then sold ~2,500 assets on to Dominion Harbor (announced 2025-02-19). This is a corporate portfolio divestiture, not a Chapter 7/11 sale — do not cite it as a Kodak/Nortel analog.

7. Privateering — NOT PRESENT (on current evidence).
Classic privateering requires the originating operating company to retain a beneficial interest and benefit from the NPE's assertions against its competitors. Here GE exited completely — GE sold its licensing arm to Dolby, Dolby sold the assets outright to Dominion Harbor, and the assertions run against Toyota and Nissan, not against GE competitors. No SEC filing, license-back, or revenue-share linking GE to Bunker Hill's recoveries was found. Caveat: if Dolby retained any economic interest in the Edison Innovations acquisition, that would convert links 2–4 into a privateering structure. The press language ("held them for sale") suggests a clean flip, but the transaction documents were not reviewed.

8. Defensive aggregator (anti-NPE) — NOT PRESENT.
The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN. It terminates at an asserting entity that filed two infringement suits (2:25-cv-01133; 2:26-cv-00231). Unified Patents' involvement here is adverse (challenging Bunker Hill's patents), not ownership — do not mistake Unified's prior-art publications for a defensive acquisition.

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Verdict

NPE — high confidence.

Justification: three strong signals stack. (1) Shell-entity transfer — the asset moved from operating-company GE through GE IP Licensing → Dolby IP Licensing → Edison Innovations → Bunker Hill Technologies, terminating at a Dominion Harbor entity with no products. (2) Known asserter — Bunker Hill/Dominion Harbor is classified "Non Practicing Entity" by Stanford's NPE database and publicly identified by Unified Patents as "an NPE and entity of Dominion Harbor Enterprises," with two E.D. Tex. suits filed against Toyota (2:25-cv-01133, 2025-11-18) and Nissan (2:26-cv-00231, 2026-03-19) asserting US 10,374,529 alongside eight sibling patents. (3) Cascading transfers — four recorded assignments in ~13 months (2025-02-20 Dolby→Edison; 2025-03-26 GE→GE IP Licensing; 2025-03-26 change of name to Dolby IP Licensing; 2026-04-09 Edison→Bunker Hill quitclaim). The single unresolved element is signal 3 (repeat correspondent) — no reel/frame or correspondent data was retrievable in this pass.

Verify against primary source: search patent number 10374529 at USPTO Assignment Center — https://assignmentcenter.uspto.gov/ (mirror index: https://assignment.uspto.gov/patent/index.html) — and capture the reel/frame and correspondent of record for the 2025-02-20 and 2026-04-09 records in particular. Cross-check the patent's Google Patents legal-events tab at https://patents.google.com/patent/US10374529/en and the E.D. Tex. docket at https://dockets.justia.com/docket/texas/txedce/2:2025cv01133/[241855](/patent/241855).

Left blank rather than fabricated: all reel/frame numbers; all correspondent-of-record attorney names and firms; exact execution dates for links 2–5; any evidence of inventor departures from GE.

I'll research the prior art for US 10,374,529, focusing on the patent's own citation records and the references relevant to its claims.

I found the key prior-art references. Let me dig deeper into the specific references and the patent's own citation record.

Prior-Art Analysis — US 10,374,529 B2

Sourcing note (read first)

The strict instruction is to search the USPTO database. I want to be transparent about what I could and could not retrieve:

• I could not directly open the USPTO PatentCenter/PAIR "References Cited" front-page list for 10,374,529 (those pages sit behind a session/login and did not render in retrieval). So I am not quoting the examiner's signed PTO-892 citation list verbatim.
• What I could retrieve and ground on: (a) the Google Patents record for US 10,374,529 (already in the full text above); (b) a Unified Patents invalidity chart captioned for US 10,374,529; and (c) the parallel Unified Patents chart for family member US 10,291,158, which reuses the same references against the same architecture.
• This is a cross-reference, not a contradiction, with the previously generated section: that section flagged the same Unified Patents chart and the same two references (US 2012/0019172 A1 and US 2011/0227534 A1). Nothing here contradicts the earlier work; it deepens it.

So the references below are the ones actually applied against the '529 claims in the public invalidity chart, plus their bibliographic data as retrieved. Treat the examiner-citation list as unverified.

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Reference A — US 2011/0227534 A1

Brief description (from the chart's quotations): A hybrid vehicle 100 having power storage devices 10-1…10-3, system main relays 11-1…11-3, converters 12-1, 12-2, a main positive/negative bus, inverters 30-1, 30-2, motor generators 32-1 and 32-2, a power split device 34, an engine 36, and a driving wheel 38. The motor generators are AC machines (e.g., permanent-magnet synchronous). Power split device 34 is a planetary gear (sun, pinion, carrier, ring); the ring gear is coupled to motor generator 32-2 and driving wheel 38; the sun gear to 32-1; the carrier to the engine crankshaft. An MG-ECU 40 generates converter drive signals (PWC1/PWC2) and inverter drive signals (PW11/PW12), i.e., independent control of two motor/generator channels. Motor generator 32-2 can regenerate energy from the wheel during braking.

Claims it potentially anticipates (§ 102):

• Claim 1 / Claim 20 — discloses the ESS + two electric motor/generators + power split device comprising a planetary set + load coupled to the second motor/generator via the power split device. It is the strongest single-reference match to the structural preamble of claims 1 and 20. Caveat: the reference as quoted ties the carrier to an engine 36 and does not, in the quoted passages, expressly disclose the recited "transmission device coupled to the first motor/generator" disposed between the first motor/generator and the power split device, nor the "first mode = only first M/G motoring / second mode = both motoring" switching logic. So it reads more as § 102 anticipation of the architecture-dependent elements and § 103 for the mode-control limitations.
• Claim 12 — supports the "first inverter … first AC motor/generator; second inverter … second AC motor/generator" architecture (inverters 30-1, 30-2; AC machines 32-1, 32-2).
• Claim 4 / Claim 15 — ESS comprising multiple energy storage units (power storage devices 10-1…10-3).
• Claim 8 / Claim 16 — AC machines described as permanent-magnet synchronous motors (relevant to the "second motor/generator = permanent-magnet motor" limitation).
• Claim 18 / Claim 11 (generator operation) — motor generator 32-2 operating as a generator / regenerative brake during braking.

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Reference B — US 2012/0019172 A1

Brief description (from the chart's quotations): A dual-motor drive arrangement with control logic 30 that controls multiple motors so that one motor provides power at a high power output level (e.g., 100%) while a second motor operates in a regenerating mode acting as a generator / load on the first motor. The second motor's electrical generator output is captured and stored in an energy storage mechanism such as a rechargeable battery. In FIG. 11, one of the two motors (motor 146) is connected to the "drive shaft" input / main port 138, while the other (motor 144) is connected to a "wheel output" / differential port 140, so the first motor 144 imparts torque at a first speed (RPM-1) to differential port 140. The chart also notes the motors may be conventional AC induction motors with motor-drive circuitry responsive to control signals 32, and that a strategy may activate a redundant motor when "additional (i.e., burst) power is required" and de-activate it otherwise.

Claims it potentially anticipates (§ 102):

• Claim 1 / Claim 12 / Claim 20 (mode logic) — this is the reference most directly aimed at the claim's core novelty: "in a first mode only the first motor/generator is operated as a motor … in a second mode both are operated as motors." The quoted passage ("both the primary motor and the redundant motor can be activated … when additional (i.e., burst) power is required … can de-activate…") is the chart's basis for teaching single-motor vs. dual-motor operation. Caveat: the chart's quoted language frames this as power/load-level based, not expressly as "cruising" vs. "accelerating" vs. "uphill" triggers. So it is strong on the one-vs-two-motors limitation but weaker on the exact claim-recited mode-selection conditions.
• Claim 1 / Claim 11 / Claim 20 (generator mode) — directly discloses the "second motor/generator operated as a generator" in a mode (relevant to dependent claim 11 and to claim 18). Note this passage cuts against a reading where the second machine is idle in the first mode.
• Claim 1 (load coupling) — two motors coupled to a drive shaft main port and a wheel/differential output port, relevant to the "load coupled to the first motor/generator … and … to the second motor/generator" element.
• Claim 3 / Claim 9 — "energy storage mechanism, such as a rechargeable battery" and the multiple-motor drive circuitry, relevant to the power-conversion and pre-charge-adjacent elements (weaker).

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How the two references are combined in the chart

The Unified Patents chart uses them in parallel (A/B) against each element rather than as a strict two-reference § 103 combination:

• US 2011/0227534 A1 supplies the planetary power-split / dual motor-generator / multi-pack ESS hardware backbone (best for the structural elements of claims 1, 12, 20).
• US 2012/0019172 A1 supplies the single-motor-vs-both-motors motoring logic and one machine regenerating while the other drives (best for the functional "first mode / second mode" elements and for claims 11/18).

If a petitioner framed it as a § 103 combination, Reference A would be the primary reference and Reference B the secondary teaching for the mode-switching limitation.

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Claims with no strong single-reference anticipation found

• Claim 9 / Claim 17 (pre-charging switching device) and Claim 10 (unidirectional) — I did not find these elements squarely disclosed in the two charted references. These track the patent's own pre-charging switching device 16/105, which is more of a specification-level feature than an examiner citation; I could not verify a front-page reference meeting it.
• Claim 6 (battery + ultra-capacitor) — not clearly met by Reference A (which shows plural batteries/capacitors generically); a separate ultra-capacitor reference would likely be needed. Unverified without the PTO-892 list.

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Uncertainty flags (stated explicitly, per operating rules)

1. USPTO front-page citations unverified. I could not open the USPTO "References Cited" / PTO-892 list for 10,374,529. The references above are grounded in the public Unified Patents charts, which are petitioner-side invalidity contentions, not the examiner's record. There may be examiner-cited art (and applicant-submitted IDS art, e.g., the "Lists of References cited by applicant" entries visible on the family's Docket Alarm record for App. 16/866,028) that I have not enumerated.
2. Filing/application numbers for the two publications not verified. I have confirmed their publication dates (2011-09-22 and 2012-01-26) but did not independently confirm their application/serial numbers or exact § 102 subparagraph without direct USPTO access. Any serial numbers should be confirmed at the source.
3. AIA vs. pre-AIA § 102. The '529 is a 2017 continuation claiming 2012-12-03 priority, while its immediate parent (US 14/094,086) was filed 2013-12-02 — after the AIA's 2013-03-16 date. Whether AIA § 102(a)(1)/(a)(2) or pre-AIA § 102(a)/(b) governs depends on the effective filing date / any-time-claim analysis. I have flagged both rather than picking one.
4. Anticipation vs. obviousness. Neither reference, as quoted, appears to anticipate every limitation of claims 1/12/20 in a single reference — the mode-selection conditions ("cruising," "accelerating," "uphill") are the likely point of distinction. The chart's own framing is closer to § 103 than clean § 102 for the independent claims.
5. No Federal Circuit 2026 appeal for this patent surfaced in my searches (consistent with the earlier section); absence of a hit is not proof of absence.

If you can supply or authorize retrieval of the USPTO PatentCenter "References Cited" tab for 10,374,529 (and the parent 14/094,086), I can reconcile my list against the examiner's signed PTO-892 and identify any examiner-cited art I have missed.

I'll verify a few date-critical facts about the charted references before building the § 103 analysis, since obviousness hinges on whether each reference actually qualifies as prior art.

Good — I have the IPR2026-00333 petition mapping and the Unified chart. Let me pin down the date status of the Reynolds reference and confirm the Tsuzuki mode mapping, since both are outcome-determinative for § 103.

Let me confirm the remaining date-critical items (Tsuzuki/Imai Japanese publication dates and Ortmann's effective filing date) since § 102 qualification drives the whole § 103 case.

Obviousness Analysis — U.S. Patent No. 10,374,529 B2

35 U.S.C. § 103 · Built on the previously generated Patent Summary, Litigation, PTAB, Assignment and Prior Art sections

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0. How this section builds on (and refines) the earlier work

Three refinements to flag up front, because they change the analysis:

1. Reference-label inversion in the Prior Art section. That section assigned "Reference A = US 2011/0227534 A1" and "Reference B = US 2012/0019172 A1." The Unified Patents chart excerpt (retrieved again here) labels US-20110227534-A1 as "B" and the dual-motor reference as "A." The substance is unaffected — I therefore cite references by publication number only, never by "A/B," to avoid propagating the inversion.

2. Reynolds is prior art despite its 2014 publication date. The Prior Art section treated US 2014/0100726 A1's publication date as the governing date and flagged the § 102 regime as unresolved. The Unified Patents patent record for US-20140100726-A1 now shows Application No. 13/646,210, Priority Date 2012-10-04, Ford Global Technologies LLC, "Control Strategy for an Electric Machine in a Vehicle." That effective filing date precedes the '529's 2012-12-03 priority date, so Reynolds qualifies as § 102(e)(1) (pre-AIA) / § 102(a)(2) (AIA) art on its filing date, not its publication date. This is a refinement, not a contradiction.

3. The earlier section's "point of distinction" is narrower than it appeared. The Prior Art section concluded that "the mode-selection conditions (cruising, accelerating, uphill) are the likely point of distinction." That is right as to anticipation, but Toyota's IPR2026-00333 petition (Pet. Ex. 1010, as summarized on AI-LAB) supplies an express mapping — Tsuzuki's "second EV mode" (MG2 only, low speed/low accelerator) to cruise and "first EV mode" (both MGs) to accelerate/uphill — and Imai (JP 2010-221979) supplies an express uphill teaching. The distinction is a § 103 bridge, not a wall.

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1. Threshold issues

1.1 Which § 102 regime governs

The '529 issued from App. 15/453,218 (filed 2017-03-08), a continuation of App. 14/094,086 (filed 2013-12-02), which claims priority to CN 201210509493.2 (filed 2012-12-03). Because the AIA first-inventor-to-file provisions apply to applications filed on/after 2013-03-16 that contain at least one claim with an effective filing date on/after that date, the '529 sits in the transition zone.

This is not outcome-determinative, and I want to be explicit about why. Every one of the five strongest references was published more than one year before the earliest possible critical date, and therefore qualifies under pre-AIA § 102(b) and AIA § 102(a)(1) without regard to which regime applies:

Only two references are regime-dependent:

Conclusion: the § 103 case stands on pre-AIA § 102(b) art alone. Reynolds is the only "extra" reference that materially strengthens it, and it qualifies under either regime.

1.2 Level of ordinary skill in the art (PHOSITA)

I would propose: a bachelor's degree in electrical or mechanical engineering (or equivalent) plus 2–4 years of experience in hybrid/electric vehicle powertrain design, including power-split (planetary) transmissions, AC traction machine control, and DC bus/inverter power management — or a master's degree with 0–2 years. This is a routine skill level: the art is an integration art, and the level of skill is a factor that weighs toward obviousness, because a POSITA at this level combines known subsystems (motor, inverter, planetary set, ESS, controller) as a matter of ordinary engineering. In re GPAC Inc., 57 F.3d 1573, 1579 (Fed. Cir. 1995).

1.3 Claim construction of the terms that drive the analysis

Nothing in the record shows a district-court Markman order (the E.D. Tex. case was still at the scheduling stage per the Litigation section), so I apply the specification's ordinary meaning:

Note the pattern of these constructions: every one of them is broader than the specification's illustrated embodiments, and broader constructions favor the prior art. Under In re Schreiber, 128 F.3d 1473, 1477 (Fed. Cir. 1997), recitation of an intended use or mode of operation does not render patentable a claim otherwise drawn to a known structure; the mode limitations here must be given weight only to the extent they reflect an actual control capability — and the art discloses the same control capability.

1.4 Legal standard

Graham v. John Deere Co., 383 U.S. 1 (1966); KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007). The inquiry is whether the subject matter as a whole would have been obvious to a POSITA at the effective filing date. A reference is read for everything it fairly discloses to a POSITA, not merely its stated purpose — In re Fulton, 391 F.3d 1195 (Fed. Cir. 2004). The test is not whether the references anticipate; it is whether the combined teachings suggest the claimed subject matter, In re Keller, 642 F.2d 413 (CCPA 1981). Section 103 rebuttal requires evidence of unexpected results, teaching away, or a secondary consideration with nexus — attorney argument is not enough. In re Merck & Co., 800 F.2d 1091 (Fed. Cir. 1986).

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2. The decisive fact that frames everything: the accused architecture is 15 years older than the patent

Before turning to the charts, one contextual point that a petitioner should lead with and a patent owner must confront.

The Paice v. Toyota record (C.D. Cal., appeal record retrieved at https://storage.courtlistener.com/recap/gov.uscourts.cacd.469848/gov.uscourts.cacd.469848.5669.0_1.pdf) describes Toyota's production hybrid transaxle as: planetary carrier ← ICE output shaft; ring gear ← MG2 and the drive shaft; sun gear ← MG1 — i.e., a two-motor-generator, single-planetary power-split device — and states that "Toyota's first commercial hybrid electric vehicle, the 'Prius I,' was sold in Japan beginning in 1997 and in the United States beginning in 2000," with the "Prius II" drive train on sale from 2003.

That is the same architecture the '529's claims 1, 12 and 20 recite (minus the engine, which the claims do not exclude). It is powerful § 103 context: the patentee's own accused product practices the claimed topology and did so nine years before the 2012-12-03 priority date. It also corroborates what a POSITA knew.

The '529 specification's own Background section is a second admission that cuts the same way: it states that "most of the electric drive systems include a single energy storage system (ESS) or a single motor, or a dual ESS with a single motor," and identifies the exact problems (motor oversizing, high cost, low efficiency across the operating range) that the claims purport to solve. A specification that recites a known problem and the known design space is an admission that motivates the combination. See MPEP § 2144.

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3. Element mapping — independent claims 1, 12 and 20

3.1 The primary reference family

3.2 Claim-by-claim element table

Claim 1 (drive system: ESS; first and second M/G coupled to ESS; transmission device coupled to first M/G; power split device with planetary set(s) coupled to the transmission device and second M/G; load coupled to first M/G via the transmission and to second M/G via the power split; mode 1 = only first M/G motoring, selected when cruising; mode 2 = both motoring, selected when accelerating):

Claim 12 — the same architecture with the inverters expressly recited and both machines expressly AC, and with mode 2 selected when "accelerating or in an uphill mode":

Claim 20 — textually identical to claim 1 except mode 2 is selected when the vehicle "is in an uphill mode". Same mapping as claim 1, with Imai supplying the express uphill trigger.

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4. The combinations, and why a POSITA would have made them

GROUND 1 (strongest) — Tsuzuki in view of US 2011/0227534 and US 2012/0019172

Structure of the ground. Tsuzuki is the primary reference; it discloses the two-motor power-split hybrid and — critically — the exact one-motor/both-motor mode dichotomy keyed to vehicle speed and driver demand:

• "second EV mode," in which only MG2 drives, at low speed and low accelerator input → reads on "only the first motor/generator … is operated as a motor" and on cruising;
• "first EV mode," in which both MG1 and MG2 can drive the vehicle under higher accelerator input → reads on "both … are operated as motors" and on accelerating.

To the extent Tsuzuki is read not to disclose a discrete transmission device between the first M/G and the power split, or a discrete DC power-conversion device, US 2011/0227534 supplies both (converters 12-1/12-2; the rotor-to-planetary gear train), and Reynolds supplies the DC-DC/VVC.

Motivation to combine (the required articulation):

1. Same field, same problem, same solution space. All three are hybrid/EV powertrain references addressing the identical recognized problem — a single electric machine cannot deliver both high efficiency across the operating range and high peak torque without oversizing. The '529 specification concedes this problem was known (Background: "a single motor may not work with a high efficiency across the entire operating range. It will cause problems of oversize, high cost, and low efficiency…"). KSR rationale: where the problem is known and the solution is a finite set of predictable options, the combination is obvious. See In re O'Farrell, 853 F.2d 894, 903 (Fed. Cir. 1988) ("obvious to try" where the prior art gives no more than general guidance but the number of identified, predictable solutions is small).

2. Express teaching, suggestion, or motivation inside the references. US 2012/0019172 does not merely permit but expressly directs the claimed control: the second/redundant motor is "activated … when additional (i.e., burst) power is required" and de-activated otherwise. That is a textual teaching to run one motor normally and bring the second on-line for acceleration — the literal claim-1 limitation. Tsuzuki supplies the same teaching through its accelerator-demand mode map. This is a T/S/M in the references themselves, the strongest form of motivation. MPEP § 2142.

3. Combination of known elements according to known methods, predictable results. Each claimed element — battery ESS, two AC machines, DC bus with inverters, planetary power-split device, controller — was independently known and was already co-packaged in the references (US 2011/0227534 has all of them in one vehicle). Combining Tsuzuki's mode logic with that hardware is an arrangement of known parts with a predictable aggregate result: better efficiency at cruise, more torque at launch/acceleration. MPEP § 2143(A).

4. Design incentive / market forces. The '529's own stated goals — "a short acceleration time and a long running mileage" (Background) — are precisely the cost/range/performance trade-offs driving hybrid and EV development in 2012. KSR, 550 U.S. at 421 (design incentives and market forces as a rationale).

5. Reasonable expectation of success. The elements are purely electrical/mechanical aggregates with no unpredictable chemistry or biological interaction; a POSITA would expect success with a high degree of confidence. There is no teaching away — neither reference criticizes dual-motor operation, and Reference 2012/0019172 affirmatively teaches it.

GROUND 2 — US 2011/0227534 in view of US 2012/0019172 and Imai (no Tsuzuki needed)

Structure. US 2011/0227534 supplies the complete hardware backbone — plural ESS units (10-1…10-3) with dedicated converters (12-1, 12-2), separate inverters (30-1, 30-2), two AC permanent-magnet motor generators (32-1, 32-2), a planetary power-split device 34, and an ECU 40 independently commanding both channels (PWC1/PWC2, PW11/PW12). US 2012/0019172 supplies the one-motor-vs-two-motor control, and Imai supplies the express uphill trigger.

Why this combination is motivated. This is the classic KSR "use of a known technique to improve a similar device in the same way" and "applying a known technique to a known device ready for improvement." US 2011/0227534's own ECU 40 already independently controls two motor-generator channels; once a POSITA has independent dual-channel control, selectively de-activating one machine at light load is the purpose for which Reference 2012/0019172 exists. The references are like the "telephone, telegraph, and radio" in KSR — the combination is the product of ordinary creativity, not invention. 550 U.S. at 418–21.

This is also the ground that meets claim 12's/20's "uphill" limitation head-on: Imai discloses a mode in which both machines drive under high-load/uphill conditions — the express claim language.

GROUND 3 — Ortmann (or Conlon) in view of Tsuzuki / US 2011/0227534 (best for the "transmission device")

Structure. Ortmann (US 2013/0012347 A1) is described as a multi-mode powersplit powertrain having a battery, multiple motor-generators, an engine, a planetary gearset, and layshaft gearing, with modes including "one motor electric drive" and "two motor electric drive." Conlon (US 2009/0176610 A1) discloses a transmission device, gear assembly, engine and a control system operating the electric motors in input-split (engine off), compound-split (engine on), and electric-only modes.

Why it matters. The element the Prior Art section correctly identified as not expressly disclosed in the quoted passages of US 2011/0227534 — the "transmission device coupled to the first electric motor/generator" — is expressly supplied by Ortmann's layshaft gearing and Conlon's "transmission device." Both also disclose the one-motor vs. two-motor drive modes verbatim, so Ortmann/Conlon can serve as the primary reference with Tsuzuki or 2011/0227534 supplying the planetary power-split and dual-machine architecture.

Motivation. A layshaft/reduction gearing stage between an electric machine and a planetary set is the paradigm of a known technique applied to a known device ready for improvement (speed/torque matching) — KSR, 550 U.S. at 417. Neither reference teaches away; both expressly employ multiple drive modes including single- and dual-motor electric drive.

Caveat, restated: Ortmann's effective filing date is unverified. Do not plead Ground 3 until the filing date is confirmed to precede 2012-12-03. Conlon (published 2009) is safe under § 102(b).

GROUND 4 — Combined ground for the DC power-conversion limitation

Reynolds discloses separate inverters 42, 44 on a shared DC bus 50, with the battery feeding a DC-DC voltage converter (VVC) 48 that adjusts the battery voltage to the level required by the inverters and machines. Motivation: matching battery voltage to inverter/motor requirements is a known technique to improve a similar device in the same way, and it was already conventional — US 2011/0227534 discloses converters 12-1/12-2 doing exactly this function. Reynolds's stated purpose (controller reset recovery) is irrelevant; a reference is prior art for everything it fairly discloses to a POSITA, In re Fulton, 391 F.3d at 1201.

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5. Dependent claims

Net: 17 of 20 claims have a strong § 103 case on the identified art; claims 9, 10 and 17 are the only genuine gaps, and they are narrow, mechanical, well-known features — exactly the sort of limitation that yields to a targeted supplemental reference.

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6. Why the obviousness case is strong — and where it can be attacked

6.1 Rebuttal themes the patent owner will raise, and the answers

6.2 Genuine vulnerabilities in the strong case (state them, don't hide them)

1. The "transmission device" element of claims 1, 12 and 20. The Prior Art section correctly noted US 2011/0227534's quoted passages do not expressly disclose a transmission between the first M/G and the power split. The '529's own spec calls the transmission optional ("may be eliminated when the output speed of the AC traction system meets requirements"), which invites an argument that the element is not clearly met — but the safer path is to ground the element on Ortmann (layshaft gearing) or Conlon (transmission device), both of which also disclose the one-/two-motor mode dichotomy. Confirm Ortmann's date.
2. Mapping ambiguity: which machine is "first"? Claim 1's "first M/G" is the transmission-coupled machine; the "second" is the power-split-coupled machine. Tsuzuki's single-motor cruise mode uses MG2 (the output/ring-side machine), so the petition must establish that Tsuzuki's MG2 corresponds to the claimed "first" M/G (or that Tsuzuki's MG1 is transmission-coupled). Verify against the actual Pet. Ex. 1001/1010 record before adopting this mapping — third-party summaries of the IPR can be imprecise.
3. US 2012/0019172's dual-role disclosure. That reference's headline teaching is arguably single-motor drive with the second machine as a generator/load; the dual-motoring teaching rests on the "redundant motor activated for burst power" passage. If that passage is not as characterized, the reference supports claims 11/18 more cleanly than the independent claims. Confirm the quoted text.
4. Claims 9, 10, 17 (pre-charging switching device, unidirectional). No charted reference meets them. This is the most likely place for a patent owner to survive a motion or to narrow a dispute.
5. Claim 6 (battery + ultra-capacitor). No confirmed reference pairing a battery specifically with an ultra-capacitor; will need a supplemental reference or a Notice-of-Common-Knowledge-backed obviousness theory.
6. Reynolds and Ortmann are the only regime-dependent references. If the '529 is held to be entitled to a pre-AIA invention date earlier than 2012-10-04, Reynolds drops out of the primary grounds (it remains available for § 103 purposes on its 2012-10-04 § 102(e) date unless the applicant antedates it). Grounds 1 and 2 survive on the § 102(b) references alone; Ground 4 (Reynolds) would need a substitute — US 2011/0227534's converters 12-1/12-2 already supply most of it.

6.3 Per-claim confidence

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7. Uncertainty flags and contradictions

1. Reference-label inversion (contradiction). The Prior Art section labels US 2011/0227534 as "A" and US 2012/0019172 as "B"; the Unified chart excerpt appears to invert this. I have avoided A/B labels entirely. No substantive contradiction.
2. Reynolds's prior-art status (refinement, not contradiction). The Prior Art section flagged the § 102 regime as unresolved and noted Reynolds's 2014 publication. I now have App. No. 13/646,210, priority date 2012-10-04, which makes Reynolds prior art on its effective filing date. This resolves uncertainty flag #3 of that section in favor of availability.
3. Ortmann's date is unverified. I was unable to confirm the effective filing date of US 2013/0012347 A1 before reaching my tool-call limit. Do not plead Ground 3 on Ortmann until confirmed. If Ortmann fails, Conlon (US 2009/0176610 A1, published 2009-07-09) covers the same two limitations on § 102(b) alone.
4. Japanese publication dates unverified. I could not independently confirm the exact publication dates of Tsuzuki (JP 2010-036880) and Imai (JP 2010-221979). Both are cited by Toyota as prior-art printed publications in IPR2026-00333 and IPR2026-00250 respectively, which is strong corroboration, but the dates should be confirmed from JPO records and certified English translations obtained.
5. Third-party characterizations. The Tsuzuki mode mapping and the Conlon/Ortmann descriptions are drawn from petitioner-side summaries (AI-LAB/Ex Parte summaries of IPR2026-00333 and IPR2026-00250, and the Unified Patents chart), not from the primary petition exhibits. Verify against the filed petitions at PTAB E2E before relying on any of it — including my summary.
6. No Markman order exists. All constructions above are proposed, not adjudicated.
7. Date discrepancy carried forward. The prompt states the current date is April 26, 2026, but source material retrieved includes events dated through June–September 2026 (e.g., the IPR2026-00333 discretionary-denial brief of 2026-06-10 and the reported 2026-08 settlements). This does not affect the § 103 technical analysis, but it affects the procedural posture: by the later dates, the two Toyota IPRs are reported terminated–settled with no Final Written Decision, meaning no § 315(e)(2) estoppel attaches and all § 102/§ 103 grounds remain available to any party. See the PTAB section.

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8. Recommended next steps

1. Retrieve and re-verify the primary record. Pull the IPR2026-00333 petition, Pet. Ex. 1010 (the Tsuzuki mapping) and the Shahbakhti declaration from PTAB E2E or the Docket Alarm mirror, and the IPR2026-00250 petition for the Conlon/Ortmann characterizations. Toyota has already done most of the mapping work against the same-family '508 and the structurally similar '648.
2. Pull Unified Patents' '529 chart (https://www.unifiedpatents.com/s/BunkerHill_US10374529_invalidity-chart.pdf) and reproduce its element-by-element rows with exact quotations and paragraph cites for US 2011/0227534 A1 and US 2012/0019172 A1.
3. Confirm Ortmann's and Conlon's filing dates, and Tsuzuki's/Imai's JPO publication dates; obtain certified translations.
4. Close the claim 9/10/17 gap. Commission a targeted search for DC-link pre-charge switching (relay + resistor, or a unidirectional pre-charge path) in multi-inverter EV DC buses. This is the single highest-value search in the matter.
5. Close the claim 6 gap. Search for battery + ultra-capacitor (or battery + high-power-density storage) ESS architecture in power-split hybrid vehicles, c. 2010–2012.
6. Verify the machine-mapping question (which prior-art MG answers to the claimed "first" M/G) with an expert declaration, since that mapping carries the mode limitations.
7. Trip-check the § 102 regime. Confirm from the '529 file history whether the applicant made any statement under 37 C.F.R. § 1.55/1.78 regarding AIA status, and whether any claim was ever presented with an effective filing date on/after 2013-03-16.

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Bottom line. On the art already charted and petitioned against this patent family, claims 1, 12 and 20 of US 10,374,529 would likely have been obvious under § 103, and 17 of the 20 claims fall with them. The combination is motivated by (i) an express T/S/M in US 2012/0019172 to activate a redundant motor only when burst power is needed, (ii) Tsuzuki's accelerator/speed-keyed one-motor-versus-two-motor EV mode map and Imai's express uphill teaching, (iii) US 2011/0227534's one-vehicle disclosure of the entire claimed hardware backbone including plural ESS units and parallel converters, and (iv) the design incentives and known problem the '529's own Background concedes. The realistic defensive positions are narrow and mechanical: claims 9, 10 and 17 (pre-charging switching device) and claim 6 (battery + ultra-capacitor), both requiring supplemental art, plus a mapping dispute over the "transmission device" and over which machine is the claimed "first" motor/generator.