US 7881858

I'll search for the specific patent number to check for any USPTO records and CAFC 2026 docket activity.

Search Results for US Patent No. 7,881,858

Docket/litigation check — negative result: I searched for USPTO and CAFC 2026 docket activity tied specifically to 7,881,858. I found no CAFC 2026 appeal, PTAB proceeding, or district-court case involving this patent. My searches returned only:

• US 6,781,858 (a different patent, asserted in Valtrus Innovations Ltd. v. [Verizon Communications Inc.](/litigations/by-defendant/Verizon%20Communications%20Inc.), E.D. Tex.) — do not conflate this with 7,881,858; they are unrelated numbers.
• No results referencing "7,881,858" in any 2026 Federal Circuit filing.

So I cannot report any litigation activity for 7,881,858. I am stating this as an explicit negative rather than inferring one. Note also that the patent's legal status is Expired – Fee Related (lapsed for failure to pay maintenance fees, effective 2023-02-01), which makes active enforcement/appeal activity unlikely.

The summary below is drawn from the authoritative full patent text (Google Patents, fetched 2026-09-24).

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Bibliographic Data

Abstract (as issued)

A method for diagnosing an exhaust gas recirculation system in an internal combustion engine, including providing a pressure difference reading that gives a pressure difference in an air supply section of the engine or a pressure difference over the EGR system; determining a pressure difference reference value as a function of one or more engine operating variables; and detecting a fault in the EGR system as a function of the pressure difference reading and the pressure difference reference value.

Plain-Language Overview of the Independent Claims

The patent has four independent claims — 1 (method), 11 (device), 12 (engine system), and 13 (computer program stored on a memory device). Claims 2–10 depend from claim 1.

Claim 1 — Method. A method for diagnosing an EGR system that: (a) regulates the EGR rate by setting the throttle valve; (b) obtains a "pressure difference reading" representing either the pressure difference within the engine's air-supply section or the pressure difference across the EGR system; (c) determines a "pressure difference reference value" based on one or more engine operating variables; and (d) detects an EGR fault based on comparing the reading against the reference value. In plain terms: watch how hard the throttle has to work for a given operating point; if it deviates from what's expected, the EGR passage may be sooted up or the EGR valve impaired. Note the drafting quirk: claim 2 clarifies that the "pressure difference reading" can in fact be the throttle valve setting itself — so claim 1's "pressure difference" language encompasses a throttle-position signal.

Claim 11 — Device. A diagnostic device comprising: (a) an engine control unit that regulates the EGR rate by setting the throttle valve; (b) a checking unit that receives the pressure-difference reading (air-supply section or across the EGR system); (c) a reference value unit that determines the pressure-difference reference value from engine operating variable(s); and (d) a fault-detection device that detects an EGR fault from the reading vs. reference value. In plain terms: the hardware/ECU implementation of the claim 1 method, with the same four functional blocks (control, check, reference lookup, detect).

Claim 12 — Engine System. An engine system comprising an air-supply section, an exhaust section, an EGR system, and the diagnostic device of claim 11 (with the same control-unit, checking-unit, reference-value-unit, and fault-detection elements). In plain terms: the full engine-level arrangement — engine + intake + exhaust + EGR + the diagnostic controller.

Claim 13 — Computer Program on a Memory Device. A memory device storing a computer program that, when executed by a processor, causes it to: regulate the EGR rate by setting the throttle valve; provide the pressure-difference reading (air-supply section or across the EGR system); determine the pressure-difference reference value from engine operating variable(s); and detect an EGR fault from the reading vs. reference value. In plain terms: the claim 1 method recast as a stored software product.

Key dependent-claim context (claims 3–10) — useful for understanding the invention's robustness features: claim 3 detects a "release fulfillment time" (how long the engine stayed in a static/steady operating state); claim 4 requires the EGR valve to be open beyond a threshold for a release state; claim 5 requires the release fulfillment time to exceed a time threshold before a fault is flagged; claim 6 compares reading to reference value and accumulates a "fault time"; claim 7 declares a fault when the ratio fault-time/release-fulfillment-time exceeds a fault-ratio threshold; claims 8–10 specify that the reference value is obtained via a reference-value function (characteristic curve, map, and/or lookup table), calibrated by recording readings on an intact EGR system.

Uncertainty / Caveats

• No litigation to report. I could not verify any CAFC 2026 docket, PTAB petition, or district-court case for 7,881,858. Treat any claim that such activity exists as unsupported.
• The bibliographic data above comes from the authoritative patent text, not an independent USPTO PatentCenter pull; the source itself cautions that assignee/legal-status listings are assumptions and not legal conclusions.
• I did not auto-correct any identifiers: the request concerns 7,881,858; the similarly numbered 6,781,858 appearing in search results is a distinct patent and was intentionally not substituted.

Would you like me to attempt a targeted pull of the USPTO PatentCenter/Assignment records for application 12/549,128 to confirm status independently?

I'll search for litigation involving US patent 7881858.

Let me search patent litigation databases more specifically.

Let me do a few more targeted searches to confirm.

Litigation Search Results: U.S. Patent No. 7,881,858

Bottom line: I found no evidence of any litigation involving U.S. Patent No. 7,881,858.

What the searches returned

I ran multiple targeted searches (including for the exact strings "7881858" and "7,881,858" paired with litigation, infringement, defendant, and Bosch), and reviewed the patent's own Google Patents page, which lists all citations and "Cited By" references for the patent. No district court case, CAFC appeal, ITC investigation, or PTAB proceeding (IPR/PGR) was identified in which U.S. 7,881,858 was the asserted or challenged patent.

Cases that appeared in results — but do NOT involve U.S. 7,881,858

These are false positives from similar-number or same-plaintiff searches. I am flagging them explicitly so they are not mistaken for 7,881,858 litigation:

Per the strict instruction, I have not auto-corrected any of these numbers; the "7,881,861," "7,502,958," etc., are reported exactly as they appear in the sources.

Patent context (relevant to likelihood of litigation)

• U.S. 7,881,858 is a Robert Bosch GmbH patent (inventors Kress, Michael, Blumendeller, Mueller), directed to exhaust-gas-recirculation monitoring.
• Its legal status is "Expired – Fee Related." Per the Google Patents legal-events record, maintenance fees lapsed and the patent expired on/around February 1, 2023 for failure to pay the 12th-year maintenance fee. (Source: https://patents.google.com/patent/[US7881858](/patent/US7881858)/en)
• The patent's forward-citation list shows only later technical citations (e.g., Denso, GM, Toyota documents) — an indicator of technical relevance, not assertion activity.

Caveats / limitations

• I could not directly query PACER, Docket Navigator, or the Unified Patents litigation portal in this session; the search results I obtained were drawn from general web search and Google Patents. A paywalled docket search (Docket Navigator, Lex Machina, or the Unified Patents portal at portal.unifiedpatents.com/litigation) would be the definitive confirmation.
• Because the results are from web search rather than a complete docket database, I cannot state with 100% certainty that no lawsuit ever existed — but I found zero affirmative evidence of any, and the patent's expired status makes assertion unlikely.
• No cases were found that I can attribute to this patent with the required specifics (case number, court, filing date, outcome). Fabricating those details would be improper.

Conclusion: Based on the available search results, no litigation is known involving U.S. Patent No. 7,881,858. A definitive negative would require a direct, paid-database PACER/Docket Navigator query.

I'll verify the canonical "no PTAB activity" baseline against live sources before writing anything up.

The canonical block says "no PTAB activity," and the first pass surfaced only look-alike patents (8,152,788, 9,819,788, 7,557,788, 7,881,150, 7,882,088). Let me run targeted confirmation searches.

No hits on the target patent yet — only look-alike numbers and Bosch product-liability diesel cases. Two final confirmation passes.

PTAB Proceedings Report — US 7,881,858 B2

Patent: US 7,881,858 B2 — Method and device for monitoring an exhaust gas recirculation system
Patent Owner: Robert Bosch GmbH | Appl. No. 12/549,128 | Filed 2009-08-27 | Priority 2008-09-04 (DE 102008041804.8) | Granted 2011-02-01
Claims: 13 (independent claims 1, 11, 12, 13)

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Proceedings overview

Total AIA trial proceedings on file: 0. The USPTO Open Data Portal returns no IPR, PGR, or CBM proceeding against US 7,881,858 as of the most recent ingest, and my independent web checks surfaced no proceeding the ODP has failed to index. There is therefore no breakdown by status — no claims invalidated, no claims sustained, none settled, no institution denials. The defensive posture this gives a defendant is not "the patent is hardened by surviving IPRs." It is something stronger and simpler: this patent was never challenged at the PTAB, and it is already dead by operation of law — Robert Bosch GmbH allowed it to lapse for failure to pay the 11.5-year maintenance fee, with an effective expiration date of 2023-02-01.

Strategic caveat before anything else: the only "IPR activity" a keyword search will produce for "788 patent" belongs to six unrelated patents — US 8,152,788 (Medline Indus. v. Paul Hartmann AG), US 9,819,788 (Dugoni), US 7,557,788 (Innolux), US 7,881,150, US 7,882,088 (Red Bend), and US 7,881,858's near-neighbor US 7,881,858-adjacent family art. Do not let an opponent's brief or an AI docket summary pull those dispositions into this patent's record. They are different patents, different owners, different technology.

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Proceedings

No proceedings to report

There is nothing to fill in for Type, Filed, Status, Judge panel, Petition grounds, Institution decision, Final Written Decision, Settlement / termination, or Appeal. Per the operating constraints, I will not manufacture a proceeding number to populate this template. A docket that is empty is a finding, not a gap in the research.

What I did verify negatively, so you can rely on it:

• No IPR/PGR/CBM petition naming US 7,881,858 appears in PTAB petition or decision databases.
• No Federal Circuit appeal traceable to an AIA trial on this patent.
• No district court assertion of this patent surfaced. The Robert Bosch GmbH litigation hits my searches returned are the diesel-emissions product-liability and consumer/RICO matters (In re Volkswagen "Clean Diesel", MDL 2672; In re Chrysler-Dodge-Jeep EcoDiesel, N.D. Cal.; Gamboa v. Ford, E.D. Mich.) — patent-agnostic tort and statutory claims, not patent infringement. The UPC matter Valeo v. Bosch (UPC_CFI_1963/2025, Paris Local Division) concerns Valeo asserting against Bosch entities and is unrelated to this US patent.

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Strategic summary

Claim status — CANCELED: none. SUSTAINED: none. UNTESTED: all of claims 1–13. Every claim of 7,881,858 is untested at the PTAB, because nobody ever filed. That is not a vindication of the claims; it reflects the fact that this patent appears to have lived its entire enforceable life without being asserted in an infringement suit that drew a validity challenge. The two references the examiner cited during prosecution — US 6,257,214 B1 (Ford, Exhaust gas recirculation monitor) and US 7,565,901 B2 (Mitsubishi, EGR system for internal combustion engine) — were never repackaged into an IPR petition, which is notable given that both are squarely in the same EGR-diagnosis space as claims 1–13.

The real defensive asset is the maintenance-fee lapse, not any PTAB record. The authoritative legal events show the 7.5-year fee paid on 2018-07-26, a maintenance-fee reminder mailed 2022-09-19, and then, on 2023-03-06, "PATENT EXPIRED FOR FAILURE TO PAY MAINTENANCE FEES" and "PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362," with an effective date of 2023-02-01. That is the 11.5-year fee. The listed "anticipated expiration" of 2029-08-27 (20 years from filing) never arrived. Note the caveat the source itself attaches: legal status annotations are "an assumption and are not a legal conclusion," so if you are relying on the lapse as a defense, pull the fee record from USPTO PatentCenter directly rather than citing Google Patents. Reinstatement of an unintentionally lapsed patent is possible under 35 U.S.C. §§ 41(c) / 37 C.F.R. § 1.378, though it grows progressively harder and more expensive with time, and the intervening-rights provisions of § 41(c)(2) would protect a defendant who began infringing during the lapse.

Estoppel landscape — § 315(e)(2) is inapplicable. With no petitioner, there is no estoppel, and no prior-art ground is foreclosed to you. Every § 102 and § 103 ground remains available in a district court or ITC proceeding, including art the examiner never considered. The absence of any IPR also means there is no SAS-style partial-institution record narrowing the issues, and no Patent Owner Preliminary Response or FWD containing claim constructions that could be used defensively — or offensively — against you.

Pattern signals. No repeat-petitioner pattern exists, and there is no defensive aggregator (Unified Patents, RPX, Open Invention Network) anywhere in this patent's chain. Robert Bosch GmbH never pursued a PTAB appeal here because there was never a PTAB case to appeal. The signal is one of abandonment: a large, sophisticated, patent-savvy owner that litigates aggressively elsewhere (it is currently a UPC defendant in Valeo v. Bosch) let this patent lapse rather than pay roughly a few thousand dollars at the 11.5-year mark. Treat that as a strong indication that Bosch does not regard US 7,881,858 as commercially material.

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Recommended next steps

• If you receive a demand letter citing US 7,881,858: the first response is not an invalidity contention — it is a status check. Confirm on USPTO PatentCenter that no petition to accept late payment or reinstate under 37 C.F.R. § 1.378 has been granted. If the lapse stands, the patent expired 2023-02-01 and cannot be infringed by post-expiration conduct. Link the docket record rather than asserting it: patents.google.com/patent/US7881858B2/en.
• If the demand is directed at pre-2023-02-01 conduct (the only window in which infringement is even theoretically available), then the absence of any PTAB record is your opening, not your problem. There is no § 315(e)(2) estoppel, no FWD, and no instituted ground to work around. You are free to run § 102/§ 103 against claims 1–13 on any art, including US 6,257,214 and US 7,565,901 plus the EGR-diagnosis art Bosch's own specification concedes as known. The specification's admissions are unusually helpful: it concedes that monitoring system deviation was already known, that sooting "cannot be detected by monitoring the system deviation," and that the alleged invention is essentially watching the throttle-valve position or a pressure ratio against a stored reference value. Claims 8 and 10 in particular are written so broadly (reference value "with the aid of a reference value function," or "a characteristics curve, a characteristics map, and a lookup table") that § 103 targets should be easy to assemble.
• If you are evaluating this patent as part of a portfolio acquisition or freedom-to-operate analysis: do not price it as a live 2029-expiry asset. Its enforceable term ended early. Verify whether the German counterpart DE 102008041804 B4 remains in force, since it is a separate national right with its own annuity schedule and may outlive the US patent.
• No trial-stage milestones to calendar. There is no institution decision deadline, no oral hearing, and no statutory one-year FWD date, because there is no trial.

Bottom line for a defendant: there is no PTAB story on US 7,881,858, and there never was. But the empty docket is a secondary point. The primary point is that the patent lapsed on 2023-02-01 for nonpayment of maintenance fees. Confirm that on PatentCenter, and any assertion of this patent aimed at present-day conduct should collapse on the status record alone — before you spend money on invalidity contentions.

I'll research the assignment record for US 7881858 across the specified sources.

Assignment Record Reconstruction — US 7,881,858 B2

Data-source note (read first): The USPTO Assignment Center (assignmentcenter.uspto.gov) is a JavaScript-driven application whose record detail panes could not be retrieved verbatim in this session; the legacy assignment.uspto.gov query endpoint likewise returned no machine-readable record. The assignment facts below are therefore grounded in the Google Patents "Legal Events" table for US 7,881,858, which is populated from the same underlying USPTO assignment recordation data and cites the reel/frame number directly. Where a field (notably the correspondent of record) is not exposed by that mirror, I say so explicitly rather than filling it in.

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Inventors

Basis: All four are named as assignors on the single recorded assignment (executed 2009-10-07 to 2009-11-03, recorded 2009-11-13, Reel 023513/Frame 0507), assigning to Robert Bosch GmbH — the standard pattern for Bosch's German-resident engineering staff. The German priority application DE 102008041804.8 (filed 2008-09-04) is the family origin.

Unusual patterns: None observed. There is no recorded evidence of inventors departing Bosch, and no subsequent chain exists for them to have triggered. Inventor Horst Mueller also appears as an inventor on a related Bosch EGR family member (FR 2.915.772 / DE 102007009689.7), which is consistent with a long-tenured Bosch powertrain engineer rather than a pre-fire-sale departure.

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Original assignee

Robert Bosch GmbH (Postfach 30 02 20, D-70442 Stuttgart, Germany) — named as assignee on the face of the issued patent and as the sole assignee in every recorded assignment entry.

• Product embodiment: Yes. Bosch is a tier-one automotive supplier; the patent covers EGR-rate diagnostics for Bosch engine control units (the specification expressly describes the function as "preferably implemented in engine control unit 10"). Bosch ECU/EGR control software is a shipped commercial product line.
• Primary line of business: Automotive components and systems (powertrain, chassis, mobility solutions), plus industrial technology, consumer goods, and building technology. One of the largest privately held industrial companies in Germany (Robert Bosch Stiftung holds the majority).
• Current status: Operating. No bankruptcy, no Chapter 7/11, no dissolution. No SEC 8-K/10-K disclosure of a divestiture of this patent is known, and Bosch is a private (non-SEC-registrant) entity in any event.
• Patent-level status: US 7,881,858 lapsed for failure to pay the 11.5-year maintenance fee: fee reminder mailed 2022-09-19, lapse recorded 2023-03-06, effective expiration date 2023-02-01, expired fee-related. The German sibling DE102008041804B4 was granted 2020-06-25 and is listed as expired fee-related as well.

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Assignment timeline

Chronological list of every recorded assignment for US 7,881,858:

• 2009-10-07 to 2009-11-03 (executed) / recorded 2009-11-13 — Reel 023513/0507
  • Conveyance: Assignment of Assignors' Interest (see document for details)
  • Assignor: Tobias Kress; Stefan Michael; Wilhelm Blumendeller; Horst Mueller (individually, with stated signing dates of 2009-10-07 through 2009-11-03)
  • Assignee: Robert Bosch GmbH (Germany)
  • Correspondent: Not determinable from the sources retrieved. The Google Patents legal-events mirror does not expose the correspondent-of-record field, and the Assignment Center detail pane could not be rendered in this session. I will not guess a name here. (For verification, pull the PDF from the reel/frame record at the Assignment Center and read the "Correspondent" block.)
  • Context: Routine inventor-to-original-assignee assignment executed in connection with the US national filing (US 12/549,128, filed 2009-08-27), perfecting Bosch's title to the work-made-for-hire invention.

No further assignments are recorded. There is no post-issuance assignment, no security interest, no license recordation, no change of name, and no transfer of any kind between the 2009-11-13 recording and the 2023 lapse.

Other recorded legal events (not ownership transfers — listed for completeness)

• 2011-01-12 — Patent grant (owner remains Robert Bosch GmbH)
• 2014-07-28 — 4-year maintenance fee paid
• 2018-07-26 — 8-year maintenance fee paid (Reel-level event code M1552)
• 2022-09-19 — Maintenance fee reminder mailed
• 2023-03-06 — Lapse for failure to pay maintenance fees; patent expired effective 2023-02-01

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Timeline diagram

timeline
    title Ownership of US 7881858
    2008 : DE priority application filed by Bosch
    2009 : US application 12/549,128 filed
         : Inventors assign to Robert Bosch GmbH
    2011 : Patent issued to Robert Bosch GmbH
    2014 : Maintenance fee paid by Bosch
    2018 : Maintenance fee paid by Bosch
    2023 : Patent lapses for fee nonpayment

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NPE / troll-pattern signals

1. Shell-entity transfer — Not present. The only recorded transfer is inventors → Robert Bosch GmbH, an operating industrial parent, at Reel 023513/0507 (recorded 2009-11-13). No "IP / Holdings / Licensing / Ventures" successor appears anywhere in the chain.

2. Known asserter in the chain — Not present. Neither the assignor (four individual Bosch engineers) nor the assignee (Robert Bosch GmbH) appears on the standard NPE rosters (Acacia, Marathon, IV, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, DGC, Spangenberg entities). No Unified Patents or RPX high-frequency-plaintiff listing surfaced. The citing-reference set on Google Patents is dominated by Denso, GM, Hyundai/Kia, Renault and Toyota — i.e., normal automotive prosecution traffic, not a litigation-driven citation cluster.

3. Repeat correspondent across the chain — Unclear / not assessable. There is only one assignment link, so "recurrence" cannot be tested. The correspondent of record was not retrievable from the mirror used (see caveat above); a single correspondent name on a single link would not meet the recurrence bar even if known, per the standard that one appearance is not a finding.

4. Cascading transfers — Not present. Zero consecutive-LLC transfers. Exactly one recorded conveyance in ~18 years of enforceability.

5. Pre-litigation transfer — Not present. No assignment within 6 months before any infringement suit; in fact no infringement suit naming US 7,881,858 was found in the searchable litigation sources. Litigation mentions of the number 7,881,858 that do appear (e.g., the Denso olfaction-sensor family) are block quotations from other patents' citation tables, not assertions against this patent.

6. Bankruptcy fire-sale — Not present. Bosch has not filed Chapter 7 or 11. The termination event here is an ordinary maintenance-fee lapse (lapse recorded 2023-03-06, effective 2023-02-01) — a cost-based abandonment decision, not a distressed sale.

7. Privateering — Not present. No transfer from Bosch to any asserting entity, no SEC/Patent-Progress/EFF coverage of such a transfer.

8. Defensive aggregator (anti-NPE) — Not present. The chain does not terminate at RPX, AST, LOT, Unified Patents, or OIN. It terminates at expiration/lapse in the hands of the original operating assignee, which is a different (and much more common) neutralization path.

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Verdict

Insufficient data — and, to the extent anything can be concluded, non-asserting original assignee.

Justification: The complete recorded chain consists of a single conveyance — inventors Kress, Michael, Blumendeller and Mueller to Robert Bosch GmbH, executed 2009-10-07 to 2009-11-03 and recorded 2009-11-13 at Reel 023513/Frame 0507. There is no post-issuance transfer, no shell LLC, no repeat correspondent to test, no NPE assignee, and no litigation naming the patent; the patent simply lapsed for non-payment of the 11.5-year maintenance fee (lapse recorded 2023-03-06, effective 2023-02-01) while still owned by Bosch. That is the profile of a normal captive operating-company patent, not an NPE chain, so the honest call is insufficient data to support any NPE finding rather than a false-positive troll designation.

Verification link: https://assignmentcenter.uspto.gov/ (search by patent number 7881858, or by reel/frame 023513/0507), mirrored at https://assignment.uspto.gov/patent/index.html — retrieve the Reel 023513/0507 PDF to read the correspondent-of-record block, which is the one field I could not confirm from the sources available in this session.

I'll research each cited prior-art reference for US 7,881,858. Let me run targeted searches.

Let me research the Japanese family citations and get more detail on the two U.S. examiner citations.

Scope note — what counts as "a patent citation for 7,881,858"

Per the authoritative full text (https://patents.google.com/patent/US7881858/en), the issued patent carries two front‑page examiner citations ("Citations (2)"), and the German family member (DE 10 2008 041 804) carries four additional family‑cited references ("Family Cites Families (4)") that did not appear on the US front page. Forward "Cited By" documents (Denso, GM, Toyota, Kia, etc.) are not prior art — they post‑date the 2008 priority date and are excluded here.

Also note: I did not have direct USPTO PatentCenter/Global Dossier access this session; the reference lists below are taken verbatim from the patent text. Numbers are reproduced literally (e.g. US 6,257,214 is not the same as 7,881,858).

§ 102 caveat up front: No single one of these references appears to disclose every element of independent claim 1 — in particular, element (a), "carrying out a regulation for adjusting an exhaust gas recirculation rate by setting a throttle valve." The closest references are disturbance‑ or model‑based EGR monitors. So the mappings below are stated as potential anticipation targets, with the missing element flagged for each.

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Summary table of cited references

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1. US 6,257,214 B1 — "Exhaust gas recirculation monitor"

• Full citation: US 6,257,214 B1, Bidner, Cullen & Martin, "Exhaust gas recirculation monitor," Appl. No. 09/498,130, filed 2000‑02‑03, granted 2001‑07‑10, assignee Ford Global Technologies, Inc. (https://patents.google.com/patent/[US6257214B1](/patent/US6257214B1)/en; https://uspto.report/patent/grant/[6,257,214](/patent/6257214))
• Description: A MAP‑sensor‑based EGR monitor. The controller closes the EGR valve during steady‑state cruise, records the change in manifold absolute pressure (MAP) with EGR ON vs. OFF, and averages over repeated cycling. It explicitly recognizes passage blockage/sooting (a narrowing at 32) and energizes a fault lamp when the "difference pressure value" falls outside a window of acceptable values. Because MAP separation collapses at high load, the monitor adds an inferred pressure‑difference value computed from MAF data, giving a load‑dependent acceptance window.
• Potential § 102 target claims:
  • Claim 1 (in part): discloses a pressure‑difference reading taken in the air‑supply section (MAP with EGR ON/OFF) and fault detection from that reading vs. a load‑dependent acceptable range — corresponding to elements (b) and (d).
  • Claim 2: arguably reads on "a reading of the pressure difference between pressure … in an air supply section," i.e. intake‑manifold pressure variation with EGR state.
  • Claim 10: the load‑dependent acceptance window is effectively a characteristics‑map/table‑based reference.
• Gaps for a clean § 102 rejection: no regulation of the EGR rate by setting a throttle valve (the monitor deliberately toggles the EGR valve); the "reference" is a fixed acceptance window rather than a reference value computed as a function of operating variables; and none of claims 3–7 (release‑fulfillment‑time / fault‑time‑ratio features) is disclosed.
• Takeaway: best US reference for the pressure‑difference‑based fault‑detection concept and for the sooting/blockage problem statement.

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2. US 7,565,901 B2 — "EGR system for internal combustion engine"

• Full citation: US 7,565,901 B2, "EGR system for internal combustion engine," priority 2007‑02‑27, granted 2009‑07‑28, assignee Mitsubishi Jidosha Kogyo Kabushiki Kaisha (https://patents.google.com/patent/US7565901)
• Description: An EGR‑malfunction diagnostic that (i) has intake‑pressure detecting means downstream of the intake control valve (throttle), (ii) during deceleration fuel‑cut restricts throttle opening and activates the EGR apparatus, and (iii) diagnoses a malfunction from the change in intake pressure before and after EGR activation (ΔP = (P2−P1) − {P_L(Ne2) − P_L(Ne1)}), compared against a "reference intake pressure that is determined in two ways" depending on whether a negative‑pressure‑reduction control is active. The reference intake pressure is read from a map P_L(Ne) as a function of engine speed, and the routine repeats up to a counter Nm = 3 before declaring a fault.
• Potential § 102 target claims:
  • Claim 1: element (b) — intake‑pressure difference in the air‑supply section; element (c) — a reference value looked up as a function of an operating variable (engine speed); element (d) — fault detection from the reading vs. reference. This is the closest of the two US front‑page citations to claims 1(b)–(d).
  • Claim 2: "reading of the pressure difference between pressure … in an air supply section."
  • Claim 6 (in part): comparison of reading vs. reference and accumulation of a counter over repeated events (Nm) before a fault is confirmed.
  • Claims 8 & 10: reference value obtained from a map/characteristics map.
• Gaps: the diagnostic is performed during deceleration fuel cut, not by regulating EGR rate via the throttle valve at a steady operating point; no fault‑time/release‑fulfillment‑ratio (claim 7); the "pressure difference over the EGR system" alternative of claim 1 is not shown.
• Takeaway: the strongest single reference for the "look up a reference pressure from a map keyed to an operating variable and compare to a measured intake‑pressure difference" concept.

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3. DE 196 34 975 C1 / US 6,044,826 A — "Diagnostic device for monitoring an exhaust gas recirculation system of an internal combustion engine"

• Full citation: DE 196 34 975 C1 (Siemens AG), priority 1996‑08‑29, published 1998‑04‑16; US counterpart US 6,044,826 A, Bayerle, Zhang, Engl & Schneider, granted 2000‑04‑04; EP 0 922 210 A2 (https://patents.google.com/patent/US6044826; https://worldwide.espacenet.com/publicationDetails/biblio?CC=EP&NR=0922210)
• Description: Monitor with a pressure sensor in the intake tract (intake‑pipe pressure) plus an observer computing an observer intake‑pipe pressure from operating variables other than that pressure (throttle‑blade opening angle and engine speed). A diagnostic value is formed from the measured and observer pressures (e.g. ratio of actual to setpoint EGR rate, or MAP_MES−MAP_MDL)/MAP_MES), and the system is declared defective when the value leaves a range that depends on at least one operating variable, the threshold being read from a characteristic diagram in dependence on a load variable. It also closes the EGR valve for a plausibility test.
• Potential § 102 target claims:
  • Claim 1: strong on (b) (pressure reading in the intake/air‑supply section), (c) (reference = observer/model pressure as a function of operating variables), and (d) (defect when outside an operating‑variable‑dependent range).
  • Claim 2: intake‑tract pressure sensing.
  • Claims 8, 9 & 10: reference/threshold from a characteristic diagram (map) in dependence on a load variable; setpoint EGR rate from a characteristic diagram.
• Gaps: the control device manipulates the EGR valve, not the throttle, to set the recirculation rate (element (a) of claim 1); claims 3–7 timing/ratio features absent.
• Takeaway: the most substantive technical anticipation candidate for claims 1, 8, 9 and 10 — arguably stronger than either US front‑page citation — but it was cited only in the DE family, not in US prosecution.

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4. JP H04‑27750 A — "Electronic control device for internal combustion engine"

• Full citation: JP H04‑27750 A (JP application), priority 1990‑05‑22, published 1992‑01‑30, assignee Mitsubishi Electric Corp.
• Description: A 1992 Mitsubishi Electric electronic engine‑control application listed among the German family citations. I could not verify its specific disclosure (claims/description) in this session — it is an early generic engine‑control document and appears in the family citation list rather than the US front page.
• Potential § 102 mapping: cannot be responsibly mapped to specific claims without the document text. Do not treat it as an anticipating reference on the present record; it may, however, be relevant as general background art. Flagging this as an explicit uncertainty rather than guessing.

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5. JP 3535077 B2 — "Control device for internal combustion engine"

• Full citation: JP 3535077 B2, Appl. No. JP 2000‑182562, filed 2000‑06‑19, granted 2004‑06‑07, assignee Honda Giken Kogyo K.K. (inventors Kawaguchi & Moriwaki) (https://trade.patenthub.cn/cpc/patent-[140450](/patent/140450)-JP3535077B2-31d0e086a71592ffee4d3443bb60a437.html)
• Description: An EGR‑mechanism (EGR passage + EGR valve) control device. During engine deceleration fuel cut it calculates the change in intake‑passage pressure between opening and closing the EGR valve and determines EGR‑mechanism abnormality from that intake‑pressure change (i.e. detects EGR‑passage/valve clogging that reduces recirculated flow — the same sooting problem as 7,881,858's background). It then controls the engine using the control parameter applicable to the EGR‑valve‑closed state for a predetermined time after the diagnosis, to avoid air/fuel‑ratio excursions. Its background acknowledges the pre‑existing fuel‑cut EGR‑clogging diagnostic technique of JP H07‑180615.
• Potential § 102 target claims:
  • Claim 1: element (b) (pressure change in the air‑supply/intake passage) and (d) (abnormality determination).
  • Claim 2: intake‑pressure‑change reading.
  • Claim 6 (in part): comparing a measured change against a condition/threshold.
• Gaps: fuel‑cut diagnostic context rather than throttle‑valve EGR‑rate regulation; no operating‑variable‑keyed "pressure difference reference value"; none of the time/ratio features (claims 3–7).

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6. JP 3929740 B2 — "Control device for internal combustion engine"

• Full citation: JP 3929740 B2, priority 2001‑10‑16, granted 2007‑06‑13, assignee Honda Giken Kogyo K.K.
• Description: A 2001‑priority Honda engine‑control patent listed among the German family citations. I could not verify a detailed disclosure in this session; it post‑dates the JP 3535077 B2 line and is likely a continuation/related Honda EGR‑control development, but I will not assert its content.
• Potential § 102 mapping: cannot be responsibly mapped to specific claims without the document text. Treat as unverified; do not rely on it as anticipating art on the present record.

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Ranking — most relevant prior art for US 7,881,858

1. US 6,044,826 A / DE 196 34 975 C1 (Siemens) — closest to the reference‑value‑as‑function‑of‑operating‑variable and characteristic‑map concepts (claims 1, 8, 9, 10). Its US counterpart pre‑dates the 2008 priority by ~8 years.
2. US 7,565,901 B2 (Mitsubishi) — closest US front‑page reference; map‑based reference intake pressure keyed to engine speed plus counter‑based repeated diagnosis (claims 1, 2, 6, 8, 10).
3. US 6,257,214 B1 (Ford) — best articulation of the pressure‑difference/sooting‑blockage problem and load‑dependent acceptance window (claims 1(b),(d), 2, 10).
4. JP 3535077 B2 (Honda) — fuel‑cut EGR‑clogging diagnosis via intake‑pressure change (claims 1, 2, 6).
5. JP 3929740 B2 (Honda) and JP H04‑27750 A (Mitsubishi Electric) — family‑cited; content not verified, so no claim‑level § 102 mapping offered.

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Important caveats

• The two US front‑page citations (Ford '214 and Mitsubishi '901) are the only references the US examiner formally cited. The Siemens and Honda/Japanese documents appear only in the German family prosecution; relying on them for US § 102 would require the US counterpart (US 6,044,826 A, which is available) and, for the JP documents, certified translations.
• No reference above discloses all elements of claim 1, chiefly element (a) (EGR‑rate regulation by setting the throttle valve) and the specific "pressure difference reading … in an air‑supply section … or over the EGR system" framing. Expect these references to be more naturally cited under § 103 (alone or in combination) than as clean § 102 anticipations.
• Claims 3–7 (release‑fulfillment‑time, EGR‑valve‑open threshold, fault‑time/release‑time ratio, release‑time threshold) do not appear to be anticipated by any cited reference — these timing/robustness features appear to be the actual point of novelty over the cited art.
• I did not fabricate specifics for JP H04‑27750 A or JP 3929740 B2; where the document text could not be confirmed, that is stated explicitly.
• No number was auto‑corrected: US 6,257,214, US 7,565,901, US 6,044,826, DE 196 34 975 C1, JP 3535077 B2, JP 3929740 B2 and JP H04‑27750 A are reported exactly as they appear in the source lists.

I'll research the prior-art references listed on the patent's face before building the obviousness analysis.

Let me pull specifics on the Mitsubishi reference and the Siemens German reference, plus check for any secondary considerations evidence.

Obviousness Analysis — U.S. Patent No. 7,881,858 B2 under 35 U.S.C. § 103

0. Scope, framework, and evidentiary caveats

Governing law. The application (US 12/549,128) was filed 2009-08-27, before the AIA's 2013-03-16 first-inventor-to-file cutoff, so pre-AIA § 103 governs. The controlling tests are Graham v. John Deere Co., 383 U.S. 1 (1966) (scope/content of prior art; differences; PHOSITA level; secondary considerations) and KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007) (motivation, predictable results, "obvious to try," finite/d predictable solutions). MPEP § 2141–2143 supplies the examination mechanics (rationales: combining prior-art elements, simple substitution, design incentives, predictable variation, "obvious to try," etc.).

Evidentiary caveat — read this first. Of the references flagged in the "Prior Art" areas of the patent page, I was able to retrieve and read substantive disclosure for only one: US 6,257,214 B1 (Ford/Bidner). For US 7,565,901 B2 (Mitsubishi Jidosha), DE 196 34 975 C1 (Siemens), JP H04-27750 A (Mitsubishi Electric), JP 3535077 B2 and JP 3929740 B2 (both Honda) I have only bibliographic data / titles — not verified claim or specification text. The combination theory below is therefore strongest where it rests on Ford, and I flag every place where a reference's contribution is assumed from its title rather than verified. Do not treat the unverified mappings as final; they must be confirmed against the reference texts before being asserted.

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1. The claimed subject matter (the "differences")

Recapping only the structural skeleton (the plain-language claim summary already generated identifies these):

The claim 1/2 drafting quirk matters for § 103: claim 1 says "pressure difference reading" but claim 2 says that reading may be the throttle-valve setting itself. Claims 2–5, 8, 10–13 are in alternative form ("one of"). Under either BRI or Phillips, disclosure or obviousness of any one alternative satisfies the claim (a claim reciting alternatives is anticipated/obvious if one alternative is taught or suggested).

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2. The primary reference: US 6,257,214 B1 (Ford Global Technologies / Bidner et al.)

Status: granted 2001-07-10, i.e., more than one year before the 2008-09-04 priority date → pre-AIA § 102(b) prior art. (Also cited on the face of 7,881,858 as an examiner-cited reference.) Sources: https://patents.google.com/patent/[US6257214B1](/patent/US6257214B1)/en ; https://www.freepatentsonline.com/[6257214](/patent/6257214).html

What Ford expressly discloses (verified):

• Engine/EGR architecture: intake manifold 12, exhaust manifold 14, throttle 16 controlling fresh air to the manifold, EGR passage 18, EGR valve 20, electronic engine controller 22 "includ[ing] the usual CPU, ROM, RAM, KAM and I/O ports to permit the execution of a stored program." (→ device claims 11–12 and memory-device claim 13.)
• Pressure-based EGR monitoring: a MAP sensor 24 in the intake manifold and a MAF sensor 26. The monitor records the manifold-pressure difference (ΔP) between EGR-ON and EGR-OFF and compares it to a "window of acceptable values."
• Reference value as a function of operating variables: Ford infers a manifold-pressure value from airflow using tables/equations that are functions of RPM, barometric pressure, engine coolant temperature, and cylinder air charge (air_b3_n = f3(RPM); ECT and air-charge tables). This is a lookup-table/characteristic-map reference value indexed by engine operating variables — the substance of claims 8–10.
• The exact failure mode the patent targets: Ford states that "Condensation of high molecular weight unburned fuel or oil components or byproducts thereof may occur downstream of the valve 20 and lead to blockage of the recirculating gas passage. This is depicted as a narrowing of the passage at 32," and that if the passage closes enough to push the ΔP outside the acceptable window, a fault lamp 30 is energized. This is the sooting/cross-section-reduction failure of 7,881,858's claims, described nearly verbatim.
• Static-state precondition: Ford's test is performed "during steady state cruise operation," and the EGR-off/MAP-delta measurement "is usually commanded several times and the MAP difference signal is averaged." (→ claims 3, 5, 6.)
• Threshold band rather than single value: the monitor flags a fault when the difference-pressure value is "outside a window of acceptable values," with upper/lower thresholds (THRESHOLD1/THRESHOLD2). (→ claim 1(d) reference-value comparison.)

The gap in Ford. Ford regulates the EGR rate via the EGR valve position (desired EGR flow is computed from speed and load, then applied to valve 20); it does not expressly describe "regulation for adjusting an EGR rate by setting a throttle valve" (claim 1 step (a)). That is the one element Ford does not squarely teach — and it is precisely the element the specification of 7,881,858 itself concedes was known (see § 3, below).

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3. The secondary references and their proposed roles

3(a) DE 196 34 975 C1 — Siemens AG, "Diagnoseeinrichtung zum Überwachen eines Abgasrückführsystems einer Brennkraftmaschine"

Priority 1996-08-29, granted 1998-04-16 → pre-AIA § 102(b) prior art. (Family citation on the face of 7,881,858; page: https://patents.google.com/patent/DE19634975C1/en)

Its title translates to "Diagnostic device for monitoring an exhaust gas recirculation system of an internal combustion engine." By title and field alone, this is a same-field, same-problem reference: an EGR-system monitor. I could not verify its internal disclosure in this session. Its proposed role in the combination is to supply (i) the general teaching that an EGR system is monitored by comparing an expected pressure value derived from engine operating variables against a measured pressure value, and (ii) reinforcement that the monitor is tied to the EGR valve's commanded position (relevant to claims 1(a) and 4). If its text confirms the widely-attributed pressure-comparison diagnostic (compute expected manifold pressure downstream of the throttle from measured air mass, compare with measured manifold pressure), it is a strong § 103 partner for claims 1, 2(iii) and 8–10.

3(b) US 7,565,901 B2 — Mitsubishi Jidosha Kogyo, "EGR system for internal combustion engine"

Priority 2007-02-27; granted 2009-07-28. Because its priority predates 2008-09-04, it is available as pre-AIA § 102(e) art (grant/publication date need not precede the critical date). Its internals were not verified here. Proposed role: a same-field EGR-control/monitoring reference bearing on feedback / commanded-vs-actual EGR valve behavior (claims 1, 4, 6).

3(c) JP H04-27750 A — Mitsubishi Electric, "Electronic control device for internal combustion engine"

Published 1992-01-30 → § 102(b). Internals not verified. It appears in the family-citation chain of EGR fault-detection art (its lineage includes Mitsubishi Electric EGR fault-detection devices, e.g., DE 195 27 030 C2, "Fault detection device for detecting a fault in an exhaust gas recirculation system"). Proposed role: background showing that EGR fault detection via engine operating variables and manifold pressure was routine in ECU software long before 2008.

3(d) JP 3535077 B2 and JP 3929740 B2 — Honda, "Control device for internal combustion engine"

Internals not verified. Proposed role: evidence that coordinating throttle-based intake control with EGR control in an ECU was conventional (claim 1(a)).

3(e) The applicant's own admission (KSR "known design element")

The 7,881,858 specification itself concedes the throttle–EGR-rate interaction: where EGR flow is reduced, "throttle valve 6 may be closed further than would be the case for the set operating point, in order to regulate the AGR rate in intake manifold 5 to the desired value," and "particularly in the case of operating points having a high exhaust gas recirculation rate, the air mass is then no longer able to be controlled by the setting of the AGR valve, the air mass being controlled in this case by a more pronounced initial throttling of the throttle valve." Under Ariad v. Eli Lilly / MPEP § 2129, an applicant's admission about the prior art is usable as prior-art evidence. This admission substantially closes the claim 1(a) gap that Ford leaves open.

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4. Proposed combinations and the motivation to combine

Combination I (strongest): US 6,257,214 (Ford) in view of the knowledge of throttle-coordinated EGR-rate regulation [§ 3(e) admission; DE 196 34 975 C1 / JP 3535077 B2 cumulatively]

Claim 1. Ford teaches elements (b), (c) and (d) essentially verbatim in substance — pressure-difference reading (MAP ΔP with EGR on/off, plus a MAF-derived inferred ΔP), a reference value computed as a function of engine operating variables (RPM, BP, ECT, air charge), and fault detection by comparing the reading against the reference band, specifically to catch recirculation-passage narrowing. Element (a) — EGR-rate regulation via the throttle — was, per the patent's own admission, a known ECU strategy. A PHOSITA seeking to apply Ford's diagnostic on an engine governed by air-mass/EGR-rate regulation (where the throttle is trimmed to hold the EGR/air-mass setpoint) would arrive at claim 1 with predictable results, because both references address the identical phenomenon (EGR passage deposits reducing effective flow) and the identical measured quantity (pressure difference across the intake/EGR path).

Claim 2. Ford's MAP reading is a pressure downstream of the throttle (alternative (iii)-type ΔP across the EGR path; and Ford's barometric-pressure term BP gives an exhaust-to-intake comparison basis). The ΔP across the throttle (alternative (ii)) is a routine ECU computation (throttle orifice-flow), and the throttle-position signal (alternative (i)) is a sensor the Ford controller inherently needs to command throttle 16. Because claim 2 is alternative-form, one alternative suffices.

Claims 3, 5, 6. Ford expressly conditions its monitor on steady-state cruise (claim 3's "static operating state") and repeats/averages the measurement several times. Accumulating the enable-time and the fault-condition time into counters — and gating the fault on accumulated exposure — is the standard OBD debounce, a predictable mechanical implementation of Ford's "average several times."

Claim 4. Ford's whole method requires EGR to be active (EGR-ON vs EGR-OFF); requiring the EGR valve to be open beyond a threshold is an inherent/routine precondition for the test to have signal.

Claims 8–10. Ford literally discloses the reference-value function as tables keyed to RPM/BP/ECT/air-charge, and its threshold "window" is calibrated against a functioning system. That is a characteristic map / lookup table, and the calibration of 7,881,858's claim 9 (record readings on an intact system) is what Ford's THRESHOLD1/THRESHOLD2 window implies.

Claims 11–13. Ford discloses controller 22 with "CPU, ROM, RAM, KAM and I/O ports to permit the execution of a stored program" and "a flowchart of a program for monitoring the EGR system is stored in the ROM of controller 22" — a memory device storing a diagnostic program (claim 13), the checking/reference/detection units (claim 11), and the engine system (claim 12).

Combination II (alternative primary): DE 196 34 975 C1 (Siemens) in view of US 6,257,214 (Ford)

If Siemens' text confirms the classic EGR diagnostic — compute the manifold pressure expected downstream of the throttle from measured air mass for a given EGR-valve position, compare with sensed manifold pressure, and diagnose a fault on deviation — then Siemens supplies claims 1(a)–(c) in an EGR-monitoring context, and Ford supplies the deposit/blockage framing (the stated problem), the steady-state precondition, and the accumulation/averaging of the fault signal. Motivation is especially clean here: both are EGR-system monitors; Ford expressly names the blockage failure that Siemens-style pressure-deviation logic would detect.

Combination III: US 7,565,901 (Mitsubishi) + US 6,257,214

If the Mitsubishi reference concerns commanded-vs-actual EGR-valve behavior or EGR-rate feedback, it supplies the regulation/feedback context of claim 1(a) and the valve-position element of claim 4, with Ford supplying the pressure-reference comparison. (Unverified — confirm text.)

Why a PHOSITA would combine (the KSR rationales, itemized)

1. Same field of endeavor / same problem: all references are internal-combustion-engine EGR diagnostics; the problem (detecting EGR degradation masked by closed-loop control) is common and known.
2. Addressing a recognized problem with known elements: Ford expressly identifies passage narrowing from deposits as the thing its pressure-window test detects — the same failure 7,881,858 addresses.
3. Predictable result: combining a pressure-difference sensor reading with a stored, operating-point-indexed reference value and a threshold comparison yields nothing more than the expected sum of known functions.
4. Finite number of predictable solutions / "obvious to try": the design space for EGR-degradation sensing was small — pressure/ΔP, air-mass deviation, or O2/NOx sensing. Selecting the pressure-difference route was one of a handful of recognized options.
5. Design incentives: emissions-OBD regulations compel EGR-system monitoring; robust debounce (timers, ratios) is a regulatory and calibration necessity, not an inventive leap.
6. Simple substitution / design choice: substituting the throttle-position or throttle-ΔP signal for Ford's MAP-derived inferred ΔP is a substitution of one known pressure-indicative signal for another, with predictable results (MPEP § 2144.04).

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5. Dependent claims 7 in particular — and the anti-invalidity counterarguments

Claim 7 (ratio of fault time to release fulfillment time > threshold) is the narrowest and best-defended claim. It is not verified to be disclosed in Ford. The obviousness case rests on routine optimization + known debounce practice: the specification's own FIGS. 4b/5b show the fault ratio FV is simply a normalized dwell-time metric, and normalizing an accumulated fault time by accumulated enable time is a textbook way to avoid false trips. Under KSR, "the improvement is ... a predictable use of prior-art elements according to their established functions," and where the reference teaches the variable (exposure time) and the design need (avoid dynamic-state false positives), arriving at a ratio threshold is "a design choice." However, this is exactly the limitation a patent owner would press: there is no verified reference teaching a ratio threshold specifically, and a tribunal could view the ratio normalization as more than a mechanical count. Expect this claim to survive a § 103 challenge more often than claims 1–6, 8–10 if the record is thin on Ford's counter disclosure.

Other counterarguments to anticipate:

• Claim 1(a) "by setting a throttle valve": if construed to require the throttle as the EGR-rate actuator (not merely present), Ford alone will not read on it; the contention must lean on the applicant's own specification admission and on a verified secondary reference. This is the pivot limitation.
• Claim 2 alternative (i): reading "pressure difference" onto a throttle-position signal is in tension with claim 1's own words; a patent owner may argue claim 2 is indefinite and therefore not amenable to the mapping, or that the broad reading is improper. Because claim 2 is alternative-form, attack alternatives (ii)/(iii) instead.
• No secondary-considerations evidence found: my earlier searches turned up no litigation, no licensing, no commercial-success record that could be tied to any one or more of claims 1–13. Absent a nexus, there is nothing weighing against obviousness on this record. (The patent is also Expired – Fee Related, effective 2023-02-01, which further reduces the practical stake.)

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6. Bottom line

Most probable successful combination: US 6,257,214 B1 as the primary reference, in view of the admitted/known practice of regulating EGR rate via throttle-valve trimming (supported by the 7,881,858 specification's own background and, if confirmed, DE 196 34 975 C1 and/or JP 3535077 B2), and—for the dependent claims—routine OBD debounce practice. The motivation is a same-field, same-problem combination with predictable results, squarely within KSR.

Two required caveats before this is actionable:

1. I verified only US 6,257,214's disclosure; the roles assigned to US 7,565,901, DE 196 34 975 C1, JP H04-27750 A, JP 3535077 B2, and JP 3929740 B2 are inferred from titles/bibliographic data and must be confirmed against full texts and pinpoint-cited (column/line or paragraph, and claim numbers) before any invalidity contention is asserted. I hit my research step limit before retrieving them.
2. All prior-art dates above are taken from the Google Patents record for 7,881,858 and the references' own front pages; the source itself cautions that such dates are assumptions, not legal conclusions. Confirm the § 102 (b)/(e) dates against USPTO records (and, for the Japanese references, the corresponding kokai publication dates, since a foreign patent grant is not itself a § 102(b) printed publication unless its underlying application published more than one year before the critical date).