US 9115671

I'll verify the patent details against the USPTO/live sources and check for any CAFC or district court activity.

Let me run targeted checks on litigation dockets and any CAFC appeals specifically naming this patent.

Let me check whether this patent is actually asserted in the identified 2026 litigation, and look for any CAFC docket naming it.

US Patent 9,115,671 B2 — Analyst Summary

Sources consulted: the authoritative full text of US9115671B2 (Google Patents, fetched 2026‑09‑24), plus live checks of public patent dockets/aggregators for the literal number "9115671" / "9,115,671." Where the live record was silent, I say so rather than infer.

1. Bibliographic data

Assignment chain of record: Benoit → BENEBE, Inc. (rec. 2012‑11‑07, eff. 2012‑11‑06) → QFT Holdings, Inc. (rec. 2013‑09‑20, eff. 2013‑09‑18) → Holley Performance Products, Inc. (rec. 2018‑10‑30, eff. 2018‑10‑25). Multiple security interests were recorded against the portfolio (General Electric Capital, Cerberus, UBS, AEA Debt Management, Wells Fargo), most of which were later released; maintenance fees were paid for the 4th year (2019‑02‑25) and 8th year (2023‑02‑27).

Caveat on dates: The listed adjusted expiration (2033‑12‑03) is roughly 13 months later than 20 years from the 2012‑11‑07 filing date. The source does not state the basis of that adjustment (e.g., PTA), so I flag it as reported, not independently verified.

2. Abstract (verbatim)

"A hybrid fuel injection and carburetor assembly for delivering a fuel and air mixture into an intake manifold of an engine is provided. The assembly includes a housing and a plurality of inserts with Venturi-shaped bores to establish low pressure regions in the flow of air. The housing and inserts cooperate with one another to present cavities, and the inserts include apertures extending between the cavities and the low-pressure regions. The assembly also includes fuel injectors in fluid communication with the cavities. In operation, fuel is injected at a high pressure into the cavities to the point, and the pressurized fuel is delivered into the low pressure air via the apertures. Because of the large pressure difference between the pressurized fuel in the cavities and the low pressure air, the fuel becomes very atomized."

3. Plain-language overview of the independent claims

Claim 1 — Apparatus (multi-bore, most detailed)

A fuel-injection assembly mountable in place of a carburetor, defined by these elements:

• A housing with multiple bores, each running axially from an air-inlet end to an outlet end feeding the engine's intake manifold.
• A throttle valve in each bore near the outlet end, pivoted to the housing to meter airflow.
• An insert in each bore, positioned axially between the intake end and the throttle valve.
• Each insert has an outer surface and a Venturi-shaped inner surface — wide at both ends with a narrow region in between that creates a low-pressure region for the airflow.
• The insert's outer surface has an annular channel aligned axially with that narrow region, and the channel + adjacent housing wall together form an annularly-shaped cavity "defined at least partially by both said outer surface of said insert and said housing."
• Multiple fuel injectors are attached to the housing and feed high-pressure fuel into those cavities.
• Each insert has multiple circumferentially-spaced apertures carrying fuel from the cavity into the low-pressure airflow.
• The insert's inner surface also defines a shoulder facing the outlet, located axially in the narrow region, creating a turbulent region; the apertures sit next to that shoulder/ledge so fuel is injected into the turbulent, low-pressure zone.
• The housing has idle fuel paths running from the injectors to a point downstream of the throttle valves for idle operation.
• The insert outer surfaces include a groove spaced axially on either side of the channel, with a seal in each groove sealing the insert to the housing (in the specification these are the two O‑ring seal grooves bounding the high-pressure cavity).

Drafting observation (not a legal conclusion): Claim 1 introduces the feature as a "shoulder" but then recites the apertures as "disposed adjacent to said ledge." The term "ledge" appears only once; the specification consistently uses "shoulder 42." Whether that is a claim‑term antecedent issue would be a matter for claim construction, not for me to resolve.

Claim 2 — Apparatus (broader, single-bore form)

A similar assembly but recited more generically:

• A housing with at least one bore along an axis, with an insert disposed in the bore for conveying air into the intake manifold; the bore is Venturi-shaped (wide at both ends, narrow between) to present a low-pressure region.
• At least one valve pivotally attached to the housing to control airflow.
• At least one fuel injector attached to the housing for delivering fuel into the airflow.
• The housing presents a high-pressure cavity in fluid communication with the injector, and at least one aperture running from that cavity to the low-pressure region to inject high-pressure fuel into the low-pressure flow at the narrow region.
• The high-pressure cavity is defined at least partially by a groove in the outer surface of the insert and by the housing. (This is the feature drafted to capture the two-piece housing/insert architecture.)

Dependent claims 3–7 add: the downstream-facing shoulder/turbulence feature (3); a groove extending at least partially around the insert circumference (4); a full-circumference groove giving a generally annular cavity (5); a plurality of circumferentially-spaced apertures (6); and apertures generally uniformly spaced around the annular cavity (7).

Claim 8 — Method

A method of delivering a fuel/air mixture to an intake manifold:

1. Provide a housing with at least one bore and an insert in that bore, the insert having a Venturi-shaped inner surface with a narrow area between wider ends;
2. Draw air through the bore so that the air pressure is lower at the narrow area than at the wider areas;
3. Inject fuel (via at least one fuel injector) into a high-pressure cavity defined at least partially by the housing and by a groove in the insert's outer surface; and
4. Deliver the fuel from that cavity into the low-pressure air flowing through the narrow area.

Dependent claims 9–11 add turbulating the flow in the low-pressure region (9); delivering the fuel generally uniformly around the narrow area (10); and the modularity step — removing the insert and replacing it with a different insert having a differently shaped bore and/or cavity (11).

4. Litigation / CAFC 2026 check (as requested)

I searched for the literal number 9115671 / 9,115,671 in connection with 2026 litigation and Federal Circuit activity. Findings and limits:

• No CAFC 2026 docket or opinion specifically naming US 9,115,671 was located. My search returned no Federal Circuit appeal referencing this patent. I cannot rule out a docket I did not surface, so treat this as "not found," not "confirmed none."
• A 2026 patent case involving the current assignee does exist, but it does not appear to assert this patent: Holley Performance Products Inc. v. Aces Fuel Injection, Inc., No. 1:26‑cv‑00059 (E.D. Tenn., filed 2026‑03‑06), flagged as a patent matter (NOS 830) and also tagged with a copyright count. Complaint analyses circulating on the docket aggregators describe infringement allegations against the accused "Killshot Fusion" EFI systems under what are referred to as the '515 patent (independent claim 9) and the '083 patent (independent claim 1) — i.e., Holley's EFI throttle-body patents directed to fuel-component covers, fuel distribution rings, and paired bores. Those claim elements (fuel distribution ring with apertures, fuel component covers on 90°/opposite sides, horizontally extending injectors) do not correspond to the '671 claims recited above.
• The older Holley v. Quick Fuel Technology litigation, No. 1:07‑cv‑00185 (W.D. Ky., 2007–2014), was a trademark/trade dress case (nature of suit 840) predating the '671 patent and is not a '671 patent action.
• Historical note tying the parties together: US7634983 lists an assignment in which Demon Fuel Systems, Inc. (Kentucky) and Holley appear, and the '671 patent's prior-art citation list includes Pankl/other fuel-system art such as US6290215B1 (Pinsker, "Carburetor with pressurized fuel injectors") and US5809972 (Grant, "Venturi-assisted fuel injection carburetor system").

Bottom line on litigation: As of the sources I could reach, I found no evidence that US 9,115,671 has been asserted in the 2026 Holley v. Aces Fuel Injection case or in any 2026 Federal Circuit appeal. State this as a search limitation, not a definitive negative.

5. Explicit uncertainty flags

1. Litigation status is not confirmed — absence of a hit is not proof of absence; I could not query PACER, Docket Navigator, or the full CAFC docket directly.
2. Adjusted expiration date (2033‑12‑03) is taken verbatim from the source without the underlying PTA/terminal-disclaimer calculation.
3. "Patent term" and "active" status are the source's assertions and are expressly disclaimed by that source as assumptions, not legal conclusions.
4. Claim 1's "shoulder"/"ledge" wording is quoted literally from the patent; I have not auto-corrected it and flag it as a possible claim-construction issue only.
5. I did not find an authoritative record of whether any reexamination, IPR, or post-grant challenge has been filed against the '671 patent; none appeared in the assignment/legal-events data I reviewed.

I'll search multiple litigation-focused sources for US patent 9115671.

Let me search additional litigation-specific sources.

The initial searches are noisy. Let me run more targeted queries on the specific case names and patent number.

Litigation search results for US Patent 9,115,671

Short answer: I found no record of any litigation in which US 9,115,671 has been asserted. No case — plaintiff, defendant, jurisdiction, case number, filing date, or status — can be reported for this patent on the basis of my searches.

What I searched

• General web searches for the patent number tied to litigation terms ("US 9115671 litigation," "'9115671' patent lawsuit defendant," "'9,115,671' infringement complaint district court").
• Unified Patents litigation/PTAB caselist material (the portal-indexed content surfaced in results).
• Google Patents record for US 9,115,671 B2 (including its "Cited By," "Similar Documents," and "Legal Events" sections) — fetched via the authoritative page supplied to me.
• CourtListener/RECAP-hosted and PACER-derived documents referencing the patent's original assignee (BENEBE, Inc.), subsequent owners (QFT Holdings, Inc.; Holley Performance Products, Inc.), and inventor Marvin V. Benoit.

Key finding: no litigation docket for '671 was located

The Google Patents record for US 9,115,671 (https://patents.google.com/patent/US9115671/en) contains no litigation or "lawsuits" section. Its "Legal Events" are exclusively U.S. Patent & Trademark Office assignment and maintenance-fee records — chain of title (BENEBE → QFT Holdings → Holley Performance Products) and security interests (GE Capital, Cerberus, UBS, AEA, Wells Fargo) — none of which are patent infringement suits. The "Cited By" entries are later patents citing '671 as prior art (e.g., Holley's US 10,570,866; US 11,225,916; US 10,294,902), not litigation.

Adjacent matters found (NOT confirmed to assert '671)

I want to flag these carefully, because they involve the patent's owner but my search results do not show '671 among the asserted patents. Under your strict-identification rule, I am reporting them as leads, not as '671 cases:

Note also that Google Patents lists '671 in the same family as AU2013254906B2 and CA2832503C (both "Hybrid carburetor and fuel injection assembly for an internal combustion engine"); I found no litigation records for those counterparts either.

Confidence and verification caveats

• High confidence: US 9,115,671 has not been the asserted patent in the litigation documents my searches surfaced, and no docket-specific result named '671.
• Medium/low confidence on "never asserted": I could not run an exhaustive Docket Navigator / Unified Patents portal patent-number search, nor a full PACER/RECAP docket query, before my search budget was exhausted. A negative result from general web search is not proof of absence. There may be a case docket that was not indexed or not surfaced.
• Do not treat the "Aces Fuel Injection" case as a '671 case without confirming the asserted patent numbers in the actual complaint (Holley's asserted patents in that suit appear to be different patents; the numbers "'515" and "'083" appear in the complaint analysis, and those are distinct from 9,115,671).

Recommended next steps to close the gap definitively

1. Unified Patents Portal litigation caselist — search by patent number 9,115,671 (https://portal.unifiedpatents.com/litigation/caselist).
2. CourtListener / RECAP docket search for "9,115,671" and for the assignees BENEBE, QFT Holdings, and Holley Performance Products.
3. PACER party search for Holley Performance Products, Inc. (and predecessors) filtered to patent nature-of-suit, then read the complaints to identify asserted patent numbers.
4. USPTO PatentCenter / Global Dossier for the '671 file to check for any listed related proceedings.
5. Pull the full complaint in 1:26-cv-00059 (E.D. Tenn.) and verify the asserted patents against the '671 number before citing it as a '671 case.

If you can confirm which specific numbers appear in the Aces Fuel Injection complaint, I can update this table accordingly. As of now, the accurate answer is: no litigation involving US 9,115,671 is known from the sources searched.

I'll verify the structured default against live sources before writing anything.

Neither hit relates to this patent. Let me run a couple of narrower checks.

One more diligence pass — checking for litigation that would have generated a petition, and for any Unified Patents activity.

Proceedings overview

Zero (0) AIA trial proceedings — no IPR, PGR, or CBM — have ever been filed against US 9,115,671. There is no breakdown to report: 0 active, 0 claims invalidated, 0 claims sustained, 0 settled, 0 institution denials. The USPTO Open Data Portal structured block returns no AIA trial proceedings as of the most recent ingest, and a live web-search pass (Google Patents, PTAB-related document indexes, CourtListener, and general docket chatter) surfaced nothing contesting this patent. Bottom line for a defendant: all 11 claims are untested and fully live. There is no PTAB-based invalidity work product to inherit, no cancellation of any claim to point to, and no estoppel narrowing the ground set available to you.

No proceedings on file

There is no proceeding to walk through. I am not going to manufacture a docket, a panel, or an FWD — none exists. What follows is the verification trail and the near-miss you should be aware of.

Near-miss flagged for disambiguation (do not confuse with this patent):

• IPR2018-00950 — Hemosonics LLC v. C.A. Casyso AG, concerning U.S. Patent No. 9,915,671 B ("hemostasis testing device"). This is a different patent with a similar-looking number (9,915,671 vs. 9,115,671). My search returned it prominently solely because of numeral overlap. It has no bearing on US 9,115,671. Per operating rules I am not auto-correcting or merging these identifiers — they are distinct patents owned by distinct entities in unrelated technology.
• Other hits my search surfaced — IPR2018-00199/IPR2018-00282 (U.S. 7,092,671, Uniloc), IPR2020-00013 (U.S. 8,069,839, MIT/Ford), the Sunoco '671 patent in N.D. Ill. — all involve other '671 patents. None is US 9,115,671.

Additional verification note (limited confidence, flagged as such): the closest thing to an adversarial event in this patent's history is a district court matter, Holley Performance Products, Inc. v. Quick Fuel Technology (W.D. Ky. 1:07-cv-00185), in which the court's memorandum notes that Holley had settled its claims against Quick Fuel and Marvin V. Benoit, Jr. (see CourtListener docket 4802936). This predates issuance and is not a PTAB proceeding, and I did not verify the precise settlement date or its IP coverage. It matters only as provenance context: the assignment chain in the authoritative record runs Benoit → BENEBE, Inc. (2012-11-06) → QFT Holdings, Inc. (2013-09-18) → Holley Performance Products, Inc. (2018-10-25), i.e. the patent travelled from the inventor through Quick Fuel's holding company into Holley. Holley is the current assignee of record.

Strategic summary

Claim status — nothing is canceled, nothing is sustained, everything is untested. US 9,115,671 has three independent claims and eight dependents: claim 1 (apparatus, plurality of bores, insert per bore, throttle valve, annular cavity, multiple fuel injectors, shoulder/ledge, idle paths, seal grooves), claim 2 (apparatus, "at least one bore," high-pressure cavity defined at least partially by a groove in the insert's outer surface), and claim 8 (method). Claims 3–7 depend from claim 2; claims 9–11 depend from claim 8. All 11 claims stand exactly as issued on 2015-08-25, with an adjusted expiration of 2033-12-03. There is no IPR-imposed narrowing, no certificate of correction narrowing, and no disclaimer of record that I found. Any defendant's freedom-to-operate analysis must treat all three independent claims as fully in force.

Estoppel landscape — there is none, and that is the good news. Because no IPR/PGR was ever instituted, § 315(e)(2) estoppel is a null set: no petitioner, and no privy of any petitioner, is barred from raising anything. Equally, no petitioner has burned prior art or expert testimony that you could borrow. A defendant today may file a first IPR against any of claims 1–11 on any § 102 or § 103 ground the art supports, subject only to the § 315(b) one-year bar (which is triggered by service of a complaint alleging infringement of this patent — check your service date) and to § 325(d)/§ 314(a) discretionary considerations. Notably, the 13 references cited on the face of the patent (Renault US 3,868,936; Ford US 3,931,369; Toyota US 4,348,997 and US 4,378,001; Grant US 5,809,972; GE US 5,930,999; Pinsker US 6,290,215; Walbro US 4,770,131; and others) were never tested in an adversary proceeding. Some were also cited as "cited by examiner" versus third-party citations; the examiner's treatment of them is unadjudicated. That is a wide-open field.

Pattern signals — none of the usual ones are present. No serial petitioner, no Unified Patents (or other defensive aggregator) involvement that I could find, no PTAB appeal, no Federal Circuit appeal, and no IPR-driven settlement. The patent's legal-events history is exclusively security interests and corporate reassignments (GE Capital → Cerberus → UBS/AEA → Wells Fargo) — financial housekeeping, not litigation. The absence of IPRs over a 13-year life is genuinely informative here: the patent is owned by a well-capitalized operating company (Holley) rather than a litigating NPE, and Holley's public filings (10-Ks) state it does not consider its business dependent on any single patent and does not describe this patent as a material assertion asset. That profile — big-entity owner, low assertion activity — is the single most common reason a patent of this age has a clean PTAB docket.

The other side of that coin. Zero IPRs also means zero free intelligence. There is no institution decision telling you which claim terms the Board would construe narrowly, no FWD expert report mapping the art, and no Board reasoning on the "high pressure cavity defined at least partially by a groove in an outer surface of said insert" limitation that anchors claim 2. You will be building the invalidity case from scratch. My own read (clearly labeled as assessment, not a PTAB finding): claim 2 is the broadest target — it needs only "at least one bore," and its cavity-by-groove limitation is the kind of structural feature that insert-molded or machined annular fuel-distribution sleeves in the prior art may read on. Claim 1 is the narrower target because it affirmatively recites idle paths, a shoulder facing the outlet, and seal grooves on "either side" of the channel. Claim 11 (the "remove the insert and insert a different insert" step) also invites a distinct § 112 written-description/enablement attack, since the specification describes modularity as a benefit but may not enable every differently-shaped cavity the claim language sweeps in.

Recommended next steps

1. Confirm the negative yourself, and date-stamp it. Run the patent on USPTO PTAB E2E and the USPTO PatentCenter trial/assignment records before you rely on this memo. My conclusion rests on the ODP structured feed plus a web pass; if a recently filed petition has not been ingested, it could be invisible to me but visible in PatentCenter. Treat this as a point-in-time finding as of 2026-09-29, not a permanent one.
2. Do not look for a "safe to sell" opinion in this docket — there isn't one. Because no claim has been invalidated, you cannot tell a client or an adversary that "claim X is dead." Any assertion letter citing claim 1, 2, or 8 must be answered on the merits, and the standing analysis runs against a patent with 7.5+ years of remaining term (nominal expiration 2033-12-03, subject to any terminal disclaimers or PTA adjustments I did not compute).
3. Preserve your IPR window now. Calendar the § 315(b) date — one year from service of the first complaint alleging infringement of US 9,115,671. Because no previous petitioner exists, you get a full, unencumbered shot; but you also get no second bite, so the petition needs to be built as a single, complete strike on whichever independent claim is actually asserted. Given the claim-2/claim-1 breadth gap, consider a tiered petition strategy targeting the narrowest asserted claim first.
4. Attack the priority and ownership chain if it helps. The chain of interest runs Benoit → BENEBE → QFT Holdings → Holley, with security interests layered across GE Capital, Cerberus, UBS, AEA, and Wells Fargo. Nothing in this record suggests a § 102(b) derivation issue or a standing defect, but the 2013 QFT Holdings assignment and the 2018 Holley assignment (effective 2018-10-25, recorded 2018-10-30) are the two links to verify if you intend to challenge the patent owner's right to sue.
5. If you are the patent owner: the clean docket is a defensive asset. The absence of any IPR or PGR over thirteen years is a meaningful fact you can cite against a defendant's invalidity narrative and can support a request that the Board exercise § 314(a) discretion against a late-filed petition that could have been brought years earlier.

Confidence statement: I am highly confident in the "zero proceedings" conclusion based on the ODP structured block, which the prompt identifies as the canonical list. I am explicitly not asserting anything about claim-level outcomes, panels, FWDs, or settlements, because none exist to assert. The one item I could not fully verify is the exact disposition and date of the Holley v. Quick Fuel district court settlement, which is why it appears with a hedge and is marked as non-PTAB context.

I'll cross-check the record against public sources before writing up.

Let me dig for the assignment correspondent and any assertion history.

Ownership Reconstruction — US 9,115,671 B2

Patent: "Hybrid carburetor and fuel injection assembly for an internal combustion engine" • App. 13/671,196 • Filed 2012-11-07 • Issued 2015-08-25 • Current assignee of record: Holley Performance Products, Inc. • Status: Active, adjusted expiration 2033-12-03

Sourcing note (important): The Google Patents legal-events table provides reel/frame, conveyance type, assignor, assignee and effective dates, and I verified those against the patent text supplied. It does not expose the correspondent of record for these recordings. I was unable to retrieve the Assignment Center correspondent field for this patent from the sources reachable in this session, and I will not invent attorney names or firm addresses. Every reel/frame below is grounded in the supplied record; correspondent fields are marked [not retrieved] rather than guessed. One prosecution-side data point is real and citable: the published application US20140123944A1 lists its Attorney, Agent, or Firm as Dickinson Wright PLLC – Troy (Troy, MI) — that is the prosecution firm of record, which is not necessarily the recording correspondent, and I flag it as a lead only.

Inventors

• Sole named inventor. No co-inventor pattern exists here, so no "all inventors depart together" signal is applicable — there is only one inventor.
• Benoit is a career carburetor engineer: he left Holley Performance Products in 1997 to found Quick Fuel Technology, ran it ~19 years, and was awarded nine patents on fuel-system innovations. He retired 2016-08-30, roughly three years after the QFT acquisition closed (see below). This is the classic founder-exit-after-M&A pattern, not a fire-sale: the portfolio was transferred with the operating business, and the founder stayed on through the earn-out/integration period.
• Environmentally notable: BENEBE, Inc. (the first assignee) is Benoit's own holding vehicle — the name is a contraction of his surname. Both BENEBE and QFT are Kentucky entities.

Original assignee

BENEBE, Inc. (Kentucky) is the assignee named on the issued patent (and the original assignee in Google's bib data). BENOIT, MARVIN V. is admittedly the assignor of the first-recorded assignment (reel 029258/0224), so BENEBE is an inventor-owned IP-holding entity sitting on top of the operating business.

• Primary line of business: IP-holding for Quick Fuel Technology, the Bowling Green, KY maker of modular racing carburetors, fuel pumps, regulators and EFI throttle bodies. By the relevant period QFT shipped in excess of 50,000 carburetors per year — the claims are embodied in real commercial product (QFT's annular-booster "QFi" EFI throttle body line is the closest commercial read on the hybrid carburetor/EFI subject matter).
• Status: absorbed. BENEBE assigned the portfolio to QFT Holdings, Inc. in Sept 2013 as part of High Performance Industries' (HPI) acquisition of Quick Fuel Technology; QFT Holdings was in turn folded into Holley Performance Products, Inc. in 2018. BENEBE, Inc. is not the current owner of record.
• Not an NPE at origin. A personal-holding-company assignee whose products are on the shelf is a normal M&A structure, not a licensing vehicle.

Assignment timeline

All entries below are recorded at USPTO (patent-assignment records) and mirror the Google Patents legal-events table for US 9,115,671 B2. [C] = correspondent not retrieved; do not read as "none."

• 2012-11-06 (executed) / recorded 2012-11-07 — Reel 029258/0224

  • Conveyance: Assignment (ASSIGNMENT OF ASSIGNORS INTEREST)
  • Assignor: Marvin V. Benoit
  • Assignee: BENEBE, Inc., Kentucky
  • Correspondent: [not retrieved]
  • Context: founder-to-own-holding-company transfer at filing — inventor assigns to his own IP vehicle on the eve of the M&A process.

• 2013-09-18 (executed) / recorded 2013-09-20 — Reel 031249/0915

  • Conveyance: Assignment
  • Assignor: BENEBE, Inc.
  • Assignee: QFT Holdings, Inc., Kentucky
  • Correspondent: [not retrieved]
  • Context: acquisition / M&A — the Quick Fuel Technology portfolio changes hands as HPI (Monomoy Capital portfolio company, Holley's parent) buys QFT; corroborated by trade press ("Benoit sold QFT to High Performance Industries in 2012") and by the LBC Credit Partners $60M financing disclosed for that deal.

• 2014-12-08 (executed) / recorded 2014-12-08 — Reel 034539/0565

  • Conveyance: Security Agreement (AMENDMENT TO PATENT SECURITY AGREEMENT)
  • Assignor: QFT Holdings, Inc.
  • Assignee: General Electric Capital Corporation, as Agent, Connecticut
  • Correspondent: [not retrieved]
  • Context: securitization — lender collateral filing, not a transfer of ownership.

• 2015-09-22 (executed/effective) / recorded 2015-09-22 — Reel 036664/0148

  • Conveyance: Security Agreement (PATENT SECURITY AGREEMENT)
  • Assignor: Holley Performance Products Inc., QFT Holdings, Inc., Holley Performance Systems, Inc. and others
  • Assignee: Cerberus Business Finance, LLC, as Collateral Agent
  • Correspondent: [not retrieved]
  • Context: securitization — group-wide collateral grant supporting the Holley/MSD transaction era (Holley's acquisition of the MSD group closed 2015-09-22).

• 2015-09-22 (effective) / recorded 2015-09-24 — Reel 036686/0994

  • Conveyance: Release (RELEASE OF SECURITY INTEREST IN PATENT COLLATERAL)
  • Assignor: General Electric Capital Corporation
  • Assignee/beneficiary: QFT Holdings, Inc., Kentucky
  • Correspondent: [not retrieved]
  • Context: release of securitization — GE Capital lien cleared.

• 2018-10-25 (executed) / recorded 2018-10-30 — Reel 047357/0825

  • Conveyance: Assignment
  • Assignor: QFT Holdings, Inc.
  • Assignee: Holley Performance Products, Inc., Kentucky
  • Correspondent: [not retrieved]
  • Context: internal reorg — the substantive title move: QFT Holdings folds its IP into the group's principal operating entity. Same-day event: owner entity status set to large/undiscounted.

• 2018-10-26 (effective) / recorded 2018-11-05 — Reel 047419/0953

  • Conveyance: Release (RELEASE BY SECURED PARTY)
  • Assignor: Cerberus Business Finance, LLC
  • Assignee/beneficiary: QFT Holdings, Inc. (and affiliate releasees)
  • Correspondent: [not retrieved]
  • Context: release of securitization — Cerberus lien cleared as the 2018 credit facility closed.

• 2018-10-26 (effective) / recorded 2018-11-06 — Reel 047429/0343

  • Conveyance: Security Agreement (SECURITY INTEREST)
  • Assignor: Flowmaster, Inc., APR, LLC, Accel Performance Group LLC and others (Holley group)
  • Assignee: UBS AG, Stamford Branch, as Collateral Agent, Connecticut
  • Correspondent: [not retrieved]
  • Context: securitization — first-lien collateral grant on the new group credit facility.

• 2018-10-26 (effective) / recorded 2018-11-18 — Reel 048147/0510

  • Conveyance: Security Agreement (SECURITY INTEREST)
  • Assignor: Holley group entities
  • Assignee: AEA Debt Management LP, Second Lien Collateral Agent, Connecticut
  • Correspondent: [not retrieved]
  • Context: securitization — second-lien layer of the same 2018 financing.

• 2018-10-26 (effective) / recorded 2018-11-18 — Reel 048475/0125

  • Conveyance: Correction (CORRECTIVE ASSIGNMENT — delete patent numbers previously recorded at reel 047429/0343)
  • Assignor: Holley group entities
  • Assignee: UBS AG, Stamford Branch, as Collateral Agent
  • Correspondent: [not retrieved]
  • Context: corrective — housekeeping on the UBS first-lien filing; notable because it shows the same collateral agent re-recording across the group, not a new owner.

• 2021-11-18 (effective) / recorded 2021-11-19 — Reel 058214/0174

  • Conveyance: Security Agreement (SECURITY INTEREST)
  • Assignor: Holley Performance Products Inc., MSD LLC, Powerteq LLC and others
  • Assignee: Wells Fargo Bank, National Association
  • Correspondent: [not retrieved]
  • Context: securitization / refinancing — post-SPAC (Holley Inc. listed on NYSE July 2021) debt package.

• 2021-11-18 (effective) / recorded 2021-11-24 — Reel 058944/0279

  • Conveyance: Release (RELEASE BY SECURED PARTY)
  • Assignor: AEA Debt Management LP (second lien)
  • Assignee/beneficiary: Holley group entities
  • Correspondent: [not retrieved]
  • Context: release of securitization.

• 2021-11-18 (effective) / recorded 2021-11-24 — Reel 058948/0926

  • Conveyance: Release (RELEASE BY SECURED PARTY)
  • Assignor: UBS AG, Stamford Branch (first lien)
  • Assignee/beneficiary: Holley group entities
  • Correspondent: [not retrieved]
  • Context: release of securitization — UBS and AEA liens cleared on the Wells Fargo refinance.

• 2024-10-31 (effective) / recorded 2025-01-02 — Reel 069813/0457

  • Conveyance: Change of Address (single-party administrative record; no change in owner)
  • Assignor: Holley Performance Products, Inc.
  • Assignee: Holley Performance Products, Inc., Kentucky
  • Correspondent: [not retrieved]
  • Context: change-of-address only — confirms Holley remains the owner of record as of that date.

No post-issuance record transfers the patent out of the Holley / HPI corporate family. Of the 14 recorded events, exactly three move title (reels 029258/0224, 031249/0915, 047357/0825); the other eleven are lender security grants, releases and one record correction.

Timeline diagram

timeline
    title Ownership of US 9115671
    2012 : Filed and assigned by inventor to BENEBE Inc
    2013 : BENEBE assigns portfolio to QFT Holdings
    2014 : GE Capital security interest recorded
    2015 : Patent issues
         : Cerberus security agreement over Holley group
         : GE Capital lien released
    2018 : QFT Holdings assigns title to Holley Performance Products
         : Cerberus lien released
         : UBS and AEA security interests recorded
         : UBS files corrective assignment
    2021 : Wells Fargo security interest recorded
         : UBS and AEA liens released
    2024 : Holley records change of address only

NPE / troll-pattern signals

1. Shell-entity transfer — not present. The only assignees outside the inventor are BENEBE, Inc. (inventor's own vehicle, reel 029258/0224), QFT Holdings, Inc. (reel 031249/0915) and Holley Performance Products, Inc. (reel 047357/0825). All three are Kentucky entities tied to a real manufacturing business that sells tens of thousands of carburetors annually; no "IP/Licensing/Ventures" suffix appears, and no registered-agent-service address is present in the record. The 2018 QFT Holdings → Holley move is an internal reorg (both Kentucky, same corporate family, same day as the large-entity status change).

2. Known asserter in the chain — not present. None of the current or former assignees (BENEBE, QFT Holdings, Holley Performance Products) matches Acacia, Marathon, Intellectual Ventures, IPNav, Wi-LAN, Conversant/Mosaid, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, or any Spangenberg entity. The secured parties (GE Capital, Cerberus, UBS, AEA, Wells Fargo) are conventional lenders, not assertion vehicles.

3. Repeat correspondent across the chain — unclear / not assessable. The correspondent of record was [not retrieved] for every entry, so recurrence cannot be confirmed or excluded. This is a genuine evidentiary gap, not a negative finding. The only attorney-of-record data I can ground is the prosecution firm for the published application (Dickinson Wright PLLC – Troy), and Dickinson Wright is a large general-practice firm that does substantial operating-company patent work — a single appearance there is affirmatively not a finding under your own rule.

4. Cascading transfers — not present. Title moved twice in a decade: 2013-09-18 (BENEBE → QFT Holdings) and 2018-10-25 (QFT Holdings → Holley), 61 months apart. There is no chain of successive LLC hops in under 24 months, and no shared-principal pattern beyond the obvious Holley-family relationship.

5. Pre-litigation transfer — not present. The most recent title transfer (reel 047357/0825, executed 2018-10-25) predates the only litigation I can surface by years. I could not confirm that US 9,115,671 is asserted in any suit, so no assignment can be characterized as pre-litigation.

6. Bankruptcy fire-sale — not present. No Chapter 7/11 appears in the chain. The corporate history is the opposite: Monomoy Capital's 2012 buyout of HPI, the 2013 QFT add-on financed by an LBC Credit Partners $60M term loan, the 2015 MSD acquisition, and a 2021 de-SPAC onto NYSE (Holley Inc.). These are growth financings.

7. Privateering — not present. No operating company transferred this patent to a third-party NPE. Title stayed inside the Holley/HPI family through every operative link.

8. Defensive aggregator — not present. No RPX / AST / LOT / Unified / OIN entity appears anywhere in the chain. The patent remains with an operating manufacturer.

Caveat on litigation (unconfirmed, flagged rather than asserted): RPX Insight shows Holley Performance Products Inc. v. Aces Fuel Injection, Inc., 1:26-cv-00059 (E.D. Tenn., filed 2026-03-06), classified "Patent Owner: Operating Company," with US 9115671 not confirmed as one of the asserted patents in the sources reached. Separately, the earlier Holley Performance Products, Inc. v. Quick Fuel Technology, 1:07-cv-00185 (W.D. Ky., 2007–2014) was a trademark/trade-dress case from before Holley acquired QFT, and involved no assertion of this patent. Treat the 2026 case as a lead to verify against PACER and the complaint's patent schedule.

Verdict

Operating-company assertion — with the express caveat that the "assertion" half is unverified for this patent number.

The chain is an unbroken operating-company succession: inventor → BENEBE, Inc. (reel 029258/0224) → QFT Holdings, Inc. (reel 031249/0915) → Holley Performance Products, Inc. (reel 047357/0825), with every remaining recording being a lender security grant, release, corrective filing, or Holley's 2024 change-of-address entry. All assignees are Kentucky entities of one manufacturing family whose products (QFT carburetors and EFI throttle bodies) embody the claimed hybrid carburetor/EFI assembly; the secured parties (GE Capital, Cerberus, UBS, AEA, Wells Fargo) are ordinary creditors. None of the eight NPE signals is present on this record; only signal 3 is genuinely unassessable because the correspondent of record could not be retrieved, and that gap should be re-checked in USPTO Assignment Center before any conclusion resting on correspondent identity is drawn.

Verify at: https://assignmentcenter.uspto.gov/ (search patent number 9115671) and cross-check https://patents.google.com/patent/[US9115671B2](/patent/US9115671B2)/en (Legal Events) — the reel/frame numbers cited above are the exact queries to re-run.

I'll search for the patent and its cited prior art references to ground my analysis.

Let me verify the remaining cited references.

Prior-Art Analysis — US Patent 9,115,671 B2

Note on the ID search: A search returned exactly one match for the literal number 9115671 — US 9,115,671 B2, "Hybrid carburetor and fuel injection assembly for an internal combustion engine." No similar-number results were substituted. I did not auto-correct any identifier. Key bibliographic data (per the Google Patents record, https://patents.google.com/patent/[US9115671B2](/patent/US9115671B2)/en):

Because the priority date is Nov 7, 2012, all cited references below (all pre-2012) qualify as prior art (pre-AIA §§ 102(a)/(b)/(e)).

1. The 13 Cited References (backward citations on the face of the patent)

I retrieved full text for the substantive references and only face-page metadata for a few due to retrieval limits (flagged below). Source root: the "Patent Citations" table at https://patents.google.com/patent/US9115671B2/en and the FreePatentsOnline mirror https://www.freepatentsonline.com/9115671.html.

A. US 3,868,936 A — Rivere (Régie Nationale des Usines Renault), "Fuel injection systems"

• Dates: priority Mar 19, 1971; US filing Mar 16, 1972; granted Mar 4, 1975.
• Disclosure (verified): Indirect fuel injection into the intake tube upstream of the inlet valves. A fuel injector (4) sprays into a passage and, via spout orifices, into a circular fuel-inlet channel/groove formed in a cylindrical shoulder of a stepped Venturi tuyere at its neck; "at least two radial, diametrally opposite orifices open into the circular channel formed in the neck portion of the tuyere," delivering fuel into the high/possibly-sonic-speed air at the neck. A throttle (butterfly/guillotine) is placed downstream, and a second injector may be located downstream of the throttle (beneath the butterfly valve) for low-load/idle operation. (FPO: https://www.freepatentsonline.com/[3868936](/patent/3868936).html)
• Potential § 102 mapping — STRONGEST anticipation candidate:
  • Claim 2 — a fuel injector delivering fuel into a cavity/groove formed in the outer surface/shoulder of an insert, and delivered through plural apertures into the low-pressure neck of a Venturi — is closely met.
  • Claims 4, 5, 6, 7 — groove/channel around the insert with plural circumferentially spaced orifices feeding the low‑pressure region — are also closely met (claim 5's "entirety" is the only weak point).
  • Claim 8 (method) — injecting fuel into a cavity defined at least partly by a groove in the insert's outer surface, then delivering into the low-pressure air at the narrow area — is closely met.
  • Claim 1 — the additional recitations (per-bore pivoting throttle valve + insert assembly + seals in grooves + idle paths) are not clearly shown, so claim 1 is likely distinguishable.
• Confidence: medium-high for claims 2/4/5/6/8; lower for claims 1/3.

B. US 3,931,369 A — Dale et al. (Ford Motor Company), "Carburetor idle system fuel atomizer"

• Dates: filed Nov 16, 1973; granted Jan 6, 1976.
• Disclosure: A carburetor idle-system fuel atomizer (fuel delivered in the idle/low-load regime through dedicated idle passages with atomization).
• Potential § 102 mapping: Potentially relevant to claim 1's "idle paths … downstream of said throttle valves" and to claim 9 (turbulating the flow) — i.e., it addresses the idle-fuel-delivery and atomization concepts, but not the injector/annular-cavity combination. Unlikely to anticipate any full claim alone.
• Confidence: low-medium (description based on face-page metadata; full text not retrieved this session).

C. US 4,348,997 A — Takeda et al. (Toyota Jidosha Kogyo K.K.), "Fuel injection type carburetor"

• Dates: priority Aug 1, 1979; granted Sep 14, 1982.
• Disclosure: A "fuel-injection-type carburetor" — a fuel injector cooperating with a carburetor body/barrel.
• Potential § 102 mapping: Generic combination carburetor-plus-injector art potentially relevant to the preamble and broad structure of claims 1, 2, 8. The same Toyota family produced the sibling D. below.
• Confidence: low-medium (metadata-level only this session).

D. US 4,378,001 A — Takeda et al. (Toyota Jidosha Kabushiki Kaisha), "Fuel injection type carburetor"

• Dates: priority Aug 1, 1979; granted Mar 29, 1983.
• Disclosure: Same subject matter family as C — a fuel-injection-type carburetor.
• Potential § 102 mapping: Same as C; potentially relevant to claims 1/2/8 broadly, but not the specific groove-defined cavity/seal/idle-path combination.
• Confidence: low-medium (metadata-level only this session).

E. US 4,495,802 A — Kashiwaya et al. (Hitachi), "Air flow meter assembly"

• Dates: priority Dec 22, 1980; granted Jan 29, 1985.
• Disclosure: An air-flow metering device.
• Potential § 102 mapping: Peripheral. It concerns airflow measurement, not fuel delivery into a Venturi; does not anticipate any claim.
• Confidence: medium (nature of the reference is clear from its title/class).

F. US 4,517,837 A — Oyama et al. (Hitachi), "Air flow rate measuring apparatus"

• Dates: priority Apr 10, 1978; granted May 21, 1985.
• Disclosure: Air-flow-rate measurement apparatus.
• Potential § 102 mapping: Peripheral; does not anticipate any claim.
• Confidence: medium.

G. US 4,770,131 A — Tuckey (Walbro Corporation), "Fuel injector for two-stroke engine"

• Dates: filed May 7, 1987; granted Sep 13, 1988.
• Disclosure: A fuel injector arrangement for a two-stroke engine (injector mounted in a body feeding an air passage).
• Potential § 102 mapping: General relevance to injector-in-throttle-body/air-passage concepts (preamble of claims 1/2); unlikely to anticipate.
• Confidence: low-medium.

H. US 5,048,327 A — Atwood (Robert K. Atwood), "Mass air flow meter"

• Dates: filed May 17, 1990; granted Sep 17, 1991.
• Disclosure: Mass air-flow meter.
• Potential § 102 mapping: Peripheral; measurement art; does not anticipate any claim.
• Confidence: medium.

I. US 5,672,187 A — Rock et al. (Cyclone Technologies Inc.), "Cyclone vortex system and process"

• Dates: priority Nov 23, 1994; granted Sep 30, 1997.
• Disclosure: Cyclone/vortex fluid system and process.
• Potential § 102 mapping: Peripheral (fluid separation/vortex). Only tangentially relevant to the turbulence-generating concept of claims 3/9; does not anticipate any claim.
• Confidence: medium.

J. US 5,809,972 A — Grant (Barry), "Venturi-assisted fuel injection carburetor system"

• Dates: priority Jun 21, 1996; filed Jul 23, 1997; granted Sep 22, 1998.
• Disclosure (verified): Fuel at regulated pressure flows to fuel injectors in mounting blocks mounted on the sides of a carburetor center section; each injector is in fluid communication with a booster venturi ring suspended in a carburetor barrel; the injectors intermittently deliver high-pressure pulses of fuel into the barrels; the high-velocity airstream through the booster venturi lowers pressure, giving greater atomization. Claim 11 recites a fuel plenum in fluid communication with each injector; claim 13 is a method for converting a carbureted engine to fuel injection. (Google Patents; FPO: https://www.freepatentsonline.com/[5809972](/patent/5809972).html)
• Potential § 102 mapping — SECOND-STRONGEST candidate:
  • Claims 1, 2, 8 — discloses plural barrels (bores), plural injectors, high-pressure fuel delivered into the low-pressure Venturi region, a mounting-block fuel plenum (analogous to a cavity), and a conversion method. However, it delivers fuel via suspended booster venturi rings, and does not show a cavity defined by a groove in an insert, an annular channel, a downstream-facing shoulder, seals, or idle paths — so claim 1 and claim 2 are not literally anticipated in full, though claim 8's method steps are close.
  • Most likely operates as § 103 obviousness art combined with the insert/groove teaching of reference A.
• Confidence: medium for § 102 on claims 1/8; the full-claim anticipation is doubtful.

K. US 5,930,999 A — Howell et al. (General Electric Company), "Fuel injector and multi-swirler carburetor assembly"

• Dates: filed Jul 23, 1997; granted Aug 3, 1999.
• Disclosure (verified): A gas-turbine carburetor: a single fuel injector with a plurality of circumferentially spaced fuel outlets, feeding a plurality of circumferentially spaced air swirlers (each swirler inlet in flow communication with a respective fuel outlet) to increase injection points and reduce NOx.
• Potential § 102 mapping: Relevant only to the concept underlying claims 6/7 — a common injector feeding plural circumferentially spaced fuel-delivery points. It is a different technical field (turbine combustor), has no Venturi insert/groove/throttle valve/intake manifold, and does not anticipate any claim as a whole. Possible § 103 art on the plural-aperture feature.
• Confidence: medium on scope; low as an anticipatory reference.

L. US 6,290,215 B1 — Pinsker (Michael Pinsker), "Carburetor with pressurized fuel injectors"

• Dates: filed Feb 10, 2000; granted Sep 18, 2001.
• Disclosure (verified): A fuel-air premixing chamber with two opposed fuel injectors, pivotally mounted air throttle valves, and a laminar-flow wing that divides incoming air and acts as a variable venturi (air velocity up, pressure down); pressurized fuel is injected into the chamber and the fuel/air mixture is supplied to the intake manifold.
• Potential § 102 mapping: Relevant to claims 1/2/8 concepts (pressurized injectors + venturi + throttle valves + housing chamber). But it uses a laminar wing/variable venturi rather than an insert with a groove-defined annular cavity, and lacks the downstream-facing shoulder with downstream apertures, seals, and idle paths — so it does not anticipate the independent claims; § 103 relevance is moderate.
• Confidence: medium-high on scope; low as a stand-alone anticipatory reference.

M. US 7,634,983 B2 — Grant (Barry S.), "Fuel inducted and injected inlet runners for combustion engine with flow modifiers for subdividing fuel droplets"

• Dates: filed Jun 13, 2007; granted Dec 22, 2009.
• Disclosure: Inlet runners with flow modifiers for subdividing fuel droplets, for inducted and injected fuel.
• Potential § 102 mapping: Relevant to droplet subdividing/atomization (the turbulent fine-atomization aim of claims 3/9); it does not disclose the insert/groove/cavity assembly, so it does not anticipate the independent claims. Best viewed as § 103 art on atomization effect.
• Confidence: medium on scope; low as anticipatory art.

2. Non-Patent Citation (NPL)

"Holley 6425 Carburetor," http://www.dunnva.com/images, dated Nov 7, 2012.

• A catalog/webpage depiction of the Holley 6425 carburetor. As a printed publication/catalog, it is potentially a § 102(a)/(b) reference for the reservoir/general carburetor architecture, but its date (the same day as the filing/priority date) makes it vulnerable as prior art unless known public availability before Nov 7, 2012 is proven. It does not disclose an inserted Venturi with a groove-defined high-pressure cavity and plural fuel-injection apertures; it does not anticipate any claim.
• Confidence: low as anticipatory art.

3. Bottom-Line Assessment

• No single cited reference appears to fully anticipate independent claims 1, 2, or 8. Consistent with this, the patent issued with all 11 claims over these references, which suggests the examiner used them (at most) in § 103 combinations rather than as § 102 anticipation.
• Best § 102 candidates:
  1. US 3,868,936 A (Rivere/Renault) — the groove/shoulder-with-radial-orifices fed by an injector into a Venturi neck maps closely onto claims 2, 4, 5, 6, 7, and the method of claim 8, and its downstream/idle injector is relevant to claim 1's idle paths.
  2. US 5,809,972 A (Grant) — plural injectors + high-pressure fuel into a low-pressure Venturi + fuel plenum + conversion method maps onto claims 1, 2, 8 conceptually, but lacks the groove-defined insert cavity, shoulder, seals, and idle paths.
• Weak/peripheral citations (non-anticipatory): US 4,495,802; US 4,517,837; US 5,048,327; US 5,672,187; US 5,930,999 (different field); and the "Holley 6425 Carburetor" NPL.
• Likely § 103 art (not § 102): US 5,809,972 (Grant) in view of US 3,868,936 (Rivere) for the groove/cavity + aperture concept; US 6,290,215 (Pinsker) and US 5,930,999 (GE) for pressurized-injector/venturi and plural circumferentially spaced fuel-delivery features; US 7,634,983 (Grant) for droplet subdividing.

Caveats / confidence limits: Full text was retrieved for US 3,868,936; US 5,809,972; US 5,930,999; and US 6,290,215. Descriptions of US 3,931,369, US 4,348,997, US 4,378,001, US 4,495,802, US 4,517,837, US 4,770,131, US 5,048,327, US 5,672,187, and US 7,634,983 rely on the patent's face-page citation metadata (title, assignee, dates) plus general field knowledge, because my retrieval steps were exhausted before I could pull their full specifications; my per-claim mappings for those items are accordingly preliminary. A rigorous § 102/§ 103 chart should be re-run against the full text of each reference and its claims, and against the prosecution history (office actions/applicant amendments) for US 13/671,196, which would reveal exactly how the examiner and applicant treated these references.

Key URLs: https://patents.google.com/patent/US9115671B2/en · https://www.freepatentsonline.com/9115671.html · https://www.freepatentsonline.com/3868936.html · https://www.freepatentsonline.com/5809972.html · https://patents.google.com/patent/US6290215 · https://patents.google.com/patent/US5930999

I'll research the key prior-art references cited on this patent before building the § 103 analysis.

Let me examine the remaining key references.

Let me check the remaining cited references and any post-grant challenges involving this patent.

Obviousness Analysis — U.S. Patent No. 9,115,671 B2

"Hybrid carburetor and fuel injection assembly for an internal combustion engine"
Inventor: Marvin V. Benoit · Original assignee: BENEBE Inc. · Current assignee: Holley Performance Products Inc. · Appl. No. 13/671,196 · Filed 2012‑11‑07 · Granted 2015‑08‑25

1. Governing law and framework

Because the application was filed November 7, 2012 — before the March 16, 2013 effective date of the AIA first-inventor-to-file provisions — the pre-AIA 35 U.S.C. § 103(a) governs, with prior art measured under pre-AIA §§ 102(a), (b), (e), and (g).

The inquiry follows Graham v. John Deere Co., 383 U.S. 1 (1966) (scope/content of prior art; differences; PHOSITA level; secondary considerations), as refined by KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007). KSR is particularly relevant here: the claims are directed to arranging known carburetor components (venturi barrels, throttle valves, idle circuits, seals) into a known hybrid carburetor/fuel-injection architecture, with the alleged novelty residing in the location and geometry of a fuel gallery formed between a removable insert and the housing. Where the combination is "of familiar elements according to known methods" and yields no more than "predictable results," it is obvious. Id. at 416. The Federal Circuit's pre-KSR teaching that a fuel-system reference must suggest modification is superseded by KSR's "design incentives and other market forces" and "obvious to try" rationales. Id. at 417, 421.

The operative MPEP 2143 rationales available here are:

• (A) Combining prior-art elements according to known methods to yield predictable results;
• (B) Simple substitution of one known element for another (float-bowl carburetion → fuel injection);
• (C) Use of a known technique to improve a similar device in the same way (a circumferential fuel gallery feeding circumferentially spaced orifices into a venturi throat);
• (D) Applying a known technique to a known device ready for improvement (retrofit of an existing carburetor);
• (F) Design incentives/market forces (the aftermarket EFI-conversion market, which the specification itself describes).

2. Level of ordinary skill in the art (PHOSITA)

A bachelor's degree in mechanical engineering (or equivalent) plus 2–4 years of experience in carburetor and low-pressure fuel-injection design, or several more years of practical carburetor/EFI calibration experience in the performance aftermarket. This is a mature, incremental mechanical arts field; the PHOSITA is charged with knowledge of the entire carburetor art, including idle circuits, booster venturis, metering blocks, air bleeds, and O-ring sealing of fuel galleries. See In re GPAC, 57 F.3d 1573 (Fed. Cir. 1995).

3. Prior art of record (the "Prior Art section")

Key structural admission in the specification itself: the patent acknowledges that carburetors conventionally include "at least one Venturi-shaped barrel, throttle valve and float bowl," that some manufacturers "have developed hybrid carburetor fuel injector assemblies," and that converting a carbureted engine to injection is "very costly" because components must be modified. (Description, Background of the Invention.) Those admissions frame the problem the claims solve and supply much of the motivation-to-combine.

4. Claim 1 — element-by-element

Claim 1 is a plurality-of-bores, one-injector-per-barrel assembly claim. Mapping to the proposed primary combination is:

Proposed rejection — Claim 1:
Holley 6425 NPL (or the carburetor art generally) in view of Grant '972, further in view of Pinsker '215, further in view of Ford '369, and optionally GE '999.

Claim 2 (broader: "at least one bore"; cavity "defined at least partially by a groove in an outer surface of said insert and by said housing") is subsumed: if claim 1 is obvious, claim 2 is obvious. The groove-defined cavity limitation is the only meaningful addition, and it is addressed in §§ 7–8.

Claim 3 (shoulder/turbulence, apertures downstream of the shoulder) → Pinsker '215 (shock zone for droplet subdivision) and Grant '972/Toyota '997 (atomization objective). Motivation: "better atomization… more of the fuel is combusted and less fuel is wasted" (Grant '972, Background) — a stated, explicit motivation, not a hindsight construct.

Claims 4–7 (groove extends fully around → annular cavity; plurality of circumferentially spaced apertures; generally uniform spacing) → GE '999 teaches a single injector discharging through a plurality of circumferentially spaced fuel outlets to a plurality of circumferentially spaced swirlers, expressly to increase and distribute injection points. Grant '972 and Toyota '997 both identify even fuel distribution as an express objective. The uniform-spacing limitation is a result-effective variable of degree, not a patentable distinction.

5. Method claims 8–11

Claim 8 — the steps of (a) providing a housing with a bore and an insert having a venturi inner surface; (b) drawing air so that the narrow area is at lower pressure; (c) injecting fuel with an injector into a high-pressure cavity defined at least partially by the housing and a groove in the insert's outer surface; and (d) delivering fuel from the cavity into the low-pressure air.

• Steps (a)–(b) and (d) are the inherent operation of Grant '972's converted carburetor (injecting high-pressure fuel into a venturi passage so that the venturi "decrease[s] the pressure of the airstream, resulting in greater atomization").
• Grant '972 expressly claims a method of converting a carburetion system to fuel injection (claim 13), which supplies the motivation to perform the method — the very aftermarket-retrofit motive the '671 specification recites.
• Step (c)'s "groove-in-the-insert" cavity is the same limitation analyzed above; Pinsker '215 supplies the "pressurized fuel accumulated in a chamber then released into the airstream" concept.

Combination: Grant '972 + Pinsker '215 (+ Holley NPL for the base structure).

Claim 9 (turbulating) → Pinsker '215 shock zone; claim 10 (uniform circumferential delivery) → GE '999 + the express uniformity objectives of Grant '972/Toyota '997.

Claim 11 (removing the insert and inserting a different insert with a differently shaped bore/cavity) is the modularity claim. It is a method of re-tuning/maintenance, and:

• Grant '972 teaches that its architecture permits substitution of components (bowls/metering blocks out, injector blocks in) "with little modification."
• The commercial Holley NPL art is built around interchangeable tuning components (main jets, power valves, boosters, venturis) — swapping an insert to change flow characteristics is the same known technique applied to a new location.
• The '671 specification states the rationale as a bare assertion of advantage (cheaper cavity formation; performance modification by swapping inserts) with no comparative data.

Combination: Grant '972 (conversion/substitution) + Holley NPL (interchangeable tuning parts). MPEP 2143 rationale (C)/(D).

6. Why the PHOSITA would have combined these references

1. Same field, same problem, same solution category. Grant '972 and Toyota '997 are directed to exactly the problem the '671 patent identifies: a carburetor center section (or carburetor-type throttle body) fitted with fuel injectors to gain injector metering without losing venturi atomization and without replacing the manifold/head. Grant '972 even claims the conversion method. Toyota '997 states its object as improving atomization and even fuel distribution. These are not remote arts — combination is combining prior art elements according to known methods to yield predictable results (MPEP 2143(A)).
2. Explicit functional motivation supplied by the references. Grant: "it can be appreciated that a fuel system combining the high atomization of a carburetor and the precise fuel metering of fuel injectors would be desirable." That sentence alone is the motivation to place a fuel injector in fluid communication with a venturi region fed by a high-pressure gallery. The '671 specification's stated advantage ("more atomized… burns more efficiently") is the same result Grant predicted.
3. Market/design pressure. The '671 specification concedes that (i) carbureted engines remain in wide use, (ii) conversion to conventional EFI is "very costly," and (iii) aftermarket packaging is the intended market. KSR holds that such market forces and the "desire to improve" supply the motivation. Grant '972's stated purpose — allowing a user to convert a conventional carburetion system "with little modification" — is that market force made explicit.
4. Predictable result, reasonable expectation of success. Every claimed element is a mechanical expedient (a groove, a shoulder, a drilled orifice, an O-ring, a passage). Nothing in the record suggests unpredictability; the '671 patent offers no comparative data showing results beyond what the combination of venturi low pressure + high-pressure injection would predict.
5. No teaching away. None of the cited references criticizes a circumferential gallery, a removable insert, or pressurized fuel downstream of a throttle valve. Toyota's injector placement (impinging on the throttle valve) is a different design choice, not a disparagement of the claimed arrangement. In re Fulton, 391 F.3d 1195 (Fed. Cir. 2004) (a mere alternative is not a teaching away).

7. Where the rejection is strongest and weakest

Strongest limitations for the examiner:

• The venturi + throttle valve + idle circuit + housing architecture (admitted art, Holley NPL, Grant '972);
• High-pressure injectors in fluid communication with a venturi region (Grant '972, Pinsker '215, Toyota '997);
• Circumferentially spaced fuel outlets from a common fuel source (GE '999);
• Fuel delivered into a turbulence/shock zone for atomization (Pinsker '215);
• Idle fuel delivered downstream of the throttle plate (Ford '369 + conventional idle circuits).

Weakest link: the "annularly-shaped cavity defined at least partially by both the outer surface of the insert and the housing" (claim 1) and its groove-based counterpart (claims 2, 4, 5, 8). I could not verify from the available record that any of the 13 cited references discloses an annular fuel gallery formed by a groove in a removable venturi insert sealed against the surrounding housing. A rejection resting on the record alone would need a substitute reference or official notice for this element. Some caution is warranted: the patent's own statement that the two-piece housing/cavity arrangement "allows for creation of the high pressure cavity very inexpensively, i.e. without having to drill or otherwise form an interior passage" is a manufacturing-cost assertion, not a technical result, and cost-driven structure selection is generally obvious.

Non-record art I encountered during research that would materially strengthen the case (each would need to be confirmed as pre-2011–2012 art and added to the record):

• US 3,664,648 — a venturi assembly whose body 99 has an annular "groove portion 106" fed by fuel and a "row of discharge orifices 108 … arranged in closely spaced circumferential relation to one another around the outer periphery of the body." This is structurally very close to the claimed insert/groove/circumferential-orifice arrangement, in the same field, decades before the '671 filing.
• US 4,206,158 (Ford, "Sonic flow carburetor with fuel distributing means") — teaches introducing fuel below the throat in close proximity to the shock wave within a narrow axial band to prevent flow separation and improve atomization; this maps neatly onto the claim 1 "shoulder → turbulent region → apertures adjacent the shoulder" limitation.
• US 3,853,273 — a venturi sleeve with a fuel film/annular fuel introduction inside swirl vanes.
• US 4,044,077 — nozzle-matrix carburetor for homogeneous mixing at the venturi portion.

8. Secondary considerations

No secondary-consideration evidence appears in the prosecution history as reflected on the face of the patent. Should the patentee assert commercial success of the Holley/QFT throttle-body product line, it must establish nexus to the claimed invention rather than to the brand, marketing, or unclaimed features (e.g., the ECU calibration or the billet throttle body). In re GPAC. Likewise, the specification's assertions of cost savings and modularity, unsupported by data, are the "predictable advantage" type KSR discounts. There is also no evidence of copying, a long-felt but unresolved need, or industry praise on this record.

9. Collateral observations worth raising

1. NPL prior-art date problem. The sole non-patent citation is the "Holley 6425 Carburetor" page dated November 7, 2012 — the same day as the filing date. That date cannot establish a § 102(b) printed publication (which requires more than one year before filing). It is usable only under pre-AIA § 102(a) as "known or used by others in this country, or patented or described in a printed publication… before the invention thereof by the applicant," which requires an evidentiary showing of when the document was actually publicly accessible and, correlatively, of the applicant's invention date. If a rejection depends on this NPL, expect a § 102(a) dating challenge. Its value is chiefly as evidence of the ordinary skill level and the conventional 4-barrel architecture, not as anticipatory art.
2. A potentially on-point § 102(e) reference not on the face of the patent. Among the documents citing this patent is US 9,845,740 B2 (MSD LLC), titled "Throttle body fuel injection system with improved fuel distribution and idle air control," with a listed priority date of 2012‑05‑11 — roughly six months before the '671 filing date. If that reference's U.S. filing (including any provisional) predates the '671 inventors' actual invention date and it is "by another," it could qualify as pre-AIA § 102(e) prior art notwithstanding its later 2017‑12‑19 issuance. Its subject matter (fuel distribution and idle air control in a throttle-body injection system) is directly on point for claim 1's idle-path limitation. This is a lead requiring verification of the underlying application filing/publication dates — I do not have those confirmed. Note that pre-AIA § 102(e) art is antedatable by a § 1.131 declaration, so it is a softer reference than a § 102(b) publication.
3. Claim-drafting defects that bear on scope. Claim 1 recites a "shoulder" and then refers to "said ledge," which lacks antecedent basis (§ 112(b)). Claim 1 also recites idle paths extending "from said fuel injectors," whereas the specification describes them as extending "from the high pressure cavities 36." A broad reading of "from said fuel injectors" would arguably capture a far wider range of idle-circuitry arrangements than the specification enables, which broadens the claim into the prior art — the classic § 103 trap.
4. Prosecution posture. Of the 13 references on the face, several (the Hitachi, Atwood, and Cyclone air-flow/cyclone references) appear directed to flow measurement and vortex devices rather than to fuel delivery, and Pinsker '215, Grant '972, and Toyota '997 appear to be the substantively closest references. A robust obviousness position would consolidate a rejection around Grant '972 as the primary reference (it teaches the conversion concept, the injector-in-venturi architecture, and substitution of components), with Pinsker '215 for the pressurized-chamber/shock-turbulence teaching, GE '999 for circumferential outlet distribution, and Ford '369 for idle-path delivery.

10. Bottom line

• Claims 1, 2, 3, and 8–10 are, in my assessment, reasonably likely to be held obvious over Holley 6425 NPL + Grant '972 + Pinsker '215, with Ford '369 supplying the idle-path teaching, GE '999 supplying circumferentially spaced distribution, and Toyota '997 supplying the atomization/even-distribution motivation — provided the groove-defined annular cavity and the shoulder/turbulence geometry can be sourced to a verified reference (the cited record is thin on both; US 3,664,648 and US 4,206,158 would close those gaps).
• Claims 4–7 and 11 are highly vulnerable as obvious design choices (fully circumferential groove; uniform spacing; insert swapping for tuning) once the base claims fall.
• The patentee's best defense is a narrow reading under which the combination of a removable insert whose outer groove cooperates with the housing to form a sealed, pressurized annular gallery that feeds both circumferential atomizing apertures downstream of a turbulence shoulder and idle paths downstream of the throttle plate is not suggested by any single reference — i.e., arguing that the record lacks an articulated motivation to relocate a groove-formed annular gallery into a removable venturi insert. That defense is vulnerable under KSR unless the patentee produces evidence of unexpected results or nexus-backed commercial success; nothing in the record before me provides it.

Caveats: I verified the content of US 5,809,972 and US 6,290,215 and portions of US 4,348,997 and US 5,930,999 via live sources, but the internal disclosures of US 3,931,369, US 4,378,001, US 4,770,131, US 3,868,936, US 5,672,187, US 4,495,802, US 4,517,837, US 5,048,327, and US 7,634,983 could not be confirmed from the search results available to me and are characterized only from titles, dates, and assignees. Any of these could disclose additional limitations (particularly the idle-circuit and groove/gallery elements) if retrieved in full. The two MSD and Renault references flagged above require direct verification before being relied upon.