US 4798190

I'll search for current authoritative information on this patent before summarizing.

US Patent 4,798,190 — "Nozzle"

Sourcing caveat: I could not query USPTO PatentCenter or the CAFC docket system directly from this environment. The following is grounded in the authoritative full text of US 4,798,190 (Google Patents, fetched 2026-09-24), the OSTI record (OSTI ID 6239924), and targeted web searches. My search of CAFC 2026 dockets returned no case referencing US 4,798,190, which is expected given the patent expired long ago; I state this as a negative search result, not as a verified absence from every possible docket.

Bibliographic data (literal, as recorded)

Assignee-chain note: post-expiration records show a series of security interests/assignments involving Fleet Capital, U.S. Bank, Wells Fargo Foothill, UBS AG, and AEA Debt Management, with releases running to Holley Performance Products Inc. and affiliates. These are liens/reassignments, not transfers that change the named assignee of record on the face of the patent.

Abstract (as issued)

An injection nozzle utilizing nitrous oxide to aid in the introduction and atomization of fuel into a combustion chamber. A Y-shaped nozzle has a pair of input ports and a single output port. One input port introduces nitrous oxide into a hollow sleeve of the nozzle, exiting at the output port. The second input port introduces fuel; a fuel line coupled to it extends the length of the hollow nozzle and terminates at the output port. Nitrous oxide is introduced at high pressure (~500–1000 PSI); fuel at ~3–12 PSI. As nitrous oxide exits past the end of the fuel line, it creates a vacuum drawing fuel from the line, and the high pressure/vaporization atomizes the fuel for more efficient burning.

Plain-language overview of the independent claims (claims 1, 9, 13, 16)

There are four independent claims; claims 2–8, 10–12, 14–15, and 17–21 are dependent.

• Claim 1 — The basic single-nozzle architecture (no numbers). A device in an internal combustion engine for putting fuel and an oxidizing agent into the combustion chamber, where the oxidizer is at substantially higher pressure than the fuel. The housing has two inlets and one outlet, with a cavity running from the first inlet to the outlet. Oxidizer goes in the first inlet, fuel in the second. A tubular fuel line connects at one end to the fuel inlet and its far end stops right next to the outlet, so the fuel is trapped inside the tube and isolated from the surrounding cavity — i.e., fuel and oxidizer don't mix until they leave the nozzle. This "isolation" limitation is the core novelty over the cited prior art (e.g., US 3,182,646 coaxial injector; US 4,494,488 and US 4,572,140 to Ram Automotive).

• Claim 9 — The functional aspiration claim. A device for delivering fuel and nitrous oxide to a combustion chamber, using a central housing with first/second material-input members and a third material-output member and a central bore through them. Fuel enters via first input means with a fuel line inside the housing terminating at the output member; nitrous oxide enters via second input means at higher pressure than the fuel. The claim captures the Venturi/vacuum effect: nitrous oxide leaving at the third member creates low pressure at the end of the fuel line, drawing fuel out to mix with the nitrous oxide as it exits.

• Claim 13 — The angled-bore nozzle with numerical pressure ranges. A combustion-chamber nozzle with a housing having a longitudinal central bore, a second bore formed at an angle to and accessing the central bore, and an output port. Fuel enters the first input port (which carries the internal tubular fuel line ending adjacent the output port); nitrous oxide enters through the second, angled port. This claim expressly recites nitrous oxide at approximately 500–1000 PSI and fuel at approximately 3–12 PSI, and the oxidizer exiting the output port drawing fuel from the line and mixing it there. (Dependent claim 14 adds manifold-mounting threads — element 16 in the spec.)

• Claim 16 — The carburetor/plate embodiment (two-piece). A device for producing a fuel/oxidizer mixture: a top housing member with a first inlet port feeding a first groove (fuel distribution), and a bottom housing member joined to it with a second inlet port feeding a second groove (oxidizer distribution). At least one third inlet port in the bottom member links the second groove and reaches the first groove when the halves are joined; at least one outlet port in the bottom member also connects to the second groove; and a fuel line sits in each third inlet port, ending adjacent the outlet port. This maps to the FIGS. 3–5 sandwich plate that mounts on the carburetor air-cleaner stud (dependent claim 21 adds the mounting opening, element 21).

Operational takeaway

The patent's stated problem: prior-art nitrous systems used separate nitrous and fuel nozzles, so low-pressure fuel (~7 PSI) entered the manifold as a stream that puddled and burned inefficiently. The disclosed solution puts both fluids in one nozzle, keeps the fuel confined in an internal tube until the tip, and lets the high-pressure, vaporizing nitrous oxide shear/entrain and atomize the fuel into a fine mist — the nozzle "allows the high pressure nitrous oxide to flow past the fuel opening, creating the low pressure area which draws the fuel out."

Uncertainty / conflicts noted

• The primary date discrepancy in my sources: the user system prompt says today is 2026-09-30, while the prompt header says April 26, 2026. I have not used either date as a substantive fact; it does not affect the patent data.
• Secondary aggregator sources (e.g., Radaris) paraphrase the same data and add inventor cities; the cities are not in the patent front page as displayed and are treated as uncorroborated.
• I found no CAFC 2026 docket, IPR, reexamination, or district-court case involving US 4,798,190. Given the 2006 expiration, active litigation is implausible, but I cannot represent that no historical suit ever named it. The patent's real footprint is as prior art: it is cited by numerous later nitrous/fuel-nozzle patents (e.g., US 5,699,776 to Nitrous Express; US 6,935,322/App. 20050081827 to Barry S. Grant; US 6,900,188 to Holley Performance Products; US 7,147,173/App. 20040173695).

I'll research litigation involving US patent 4798190 using multiple search angles.

Let me search more targeted litigation databases.

Let me try the litigation-specific databases directly.

Findings: Litigation Involving U.S. Patent No. 4,798,190

Bottom line: I found no known litigation — district court, CAFC, or PTAB — involving U.S. Patent No. 4,798,190.

What I searched

I ran targeted searches against litigation-oriented sources (Unified Patents litigation/PTAB portals, CourtListener/RECAP, Docket Alarm, and general queries pairing the patent number with terms like "infringement," "lawsuit," "defendant," "CAFC," and "PACER"). I did not return results for similar numbers.

Results

• No district court case naming U.S. 4,798,190 as an asserted patent was surfaced.
• No CAFC appeal involving the patent was surfaced.
• No PTAB proceeding (IPR/PGR) against the patent was surfaced.
• Hits on the string "4798190" that did appear were unrelated coincidences, e.g., a Brazilian corporate registry entry ("MINIMERCADO ROSA MARLENE LTDA - ME"), an SEC filing "associated identifier" for Immuron Limited, and unrelated patent suits (such as the ITW/MOC '638 patent matter). None reference U.S. Patent 4,798,190. I am flagging these explicitly so they are not mistaken for litigation against this patent.

Important caveats

1. My searches were not exhaustive or authoritative. Unified Patents' caselist, PACER, and Docket Alarm are not fully indexed by general web search, and some are paywalled or require interactive queries. A definitive "no litigation" conclusion would require a direct Docket Navigator / Lex Machina / PACER party-and-patent search, which I could not complete here.
2. I did not fabricate any case. Per your instruction and standard practice, I will not invent plaintiff/defendant names, jurisdictions, or case numbers. I have none to report.
3. Timing context. U.S. 4,798,190 ("Nozzle"), filed 1986-05-30, granted 1989-01-17, to inventors Dale L. Vaznaian and Michael J. Thermos, assigned to Nitrous Oxide Systems, Inc. (Cypress, CA), is recorded as "Expired – Lifetime" (anticipated expiration 2006-05-30, i.e., 20 years from filing). Because the patent term has lapsed, any enforcement activity would necessarily predate ~2006, which is consistent with (though not proof of) the absence of modern docket entries.

Recommended next steps to confirm

• Run a direct patent-number search in Docket Navigator or Lex Machina for "4,798,190."
• Check the PACER docket for the Central District of California (the assignee's home venue) for historical cases involving Nitrous Oxide Systems, Inc.
• Query the Unified Patents Portal (portal.unifiedpatents.com/litigation/caselist?patents=4798190) directly, rather than via general search.

If you can supply access credentials or a specific venue/date range, I can refine the search. As it stands, on the evidence available: no litigation is known for U.S. Patent No. 4,798,190.

I'll verify the structured data with targeted web searches before finalizing.

Proceedings overview

Total AIA trial proceedings on file for US 4,798,190: 0 — zero active, zero claims invalidated, zero claims sustained, zero settled, zero institution denials. The USPTO Open Data Portal returns no IPR, PGR, or CBM proceedings (per the structured "PTAB proceedings on file" block), and my independent web searches for a petition, institution decision, final written decision, or Federal Circuit appeal naming this patent returned nothing. The bottom line for a defendant is not "the patent is hardened" nor "the claims are dead" — it is that this patent is expired and untested at the PTAB, which makes the absence of AIA activity almost inevitable rather than exculpatory: the last day of the enforceable term was 2006-05-30, roughly six years before the first IPR was ever filed under the AIA.

No proceedings to report

There is no IPR20XX-XXXXX, PGR20XX-XXXXX, or CBM20XX-XXXXX number associated with this patent in the sources I can verify. I am declining to populate the per-proceeding template, because doing so would require inventing a proceeding number, a petitioner, a panel, and a disposition — exactly the fabrication the task forbids. If the structured ODP block is empty and web search surfaces nothing, the honest answer is "none," not "none that I could find summarized below."

Two supporting data points, both verifiable from the patent record itself:

• Terminal status. Google Patents' legal-events timeline for US 4,798,190 records "Anticipated expiration" on 2006-05-30, with status "Expired - Lifetime." The 20-year term ran from the 1986-05-30 filing date; maintenance fees for years 4, 8, and 12 were paid (1992-07-06, 1996-09-18, 2000-07-14), which is consistent with expiry at end of term rather than for non-payment.
• Pre-AIA filing. The application was filed 1986-05-30, decades before the AIA's 2012-09-16 effective date. Post-grant review is unavailable as a matter of law (PGR reaches only patents with a claim having an effective filing date on or after 2013-03-16), and CBM review is unavailable because the patent claims a mechanical injection nozzle, not a "financial product or service" under AIA § 18(d)(1). That leaves IPR as the only theoretically available AIA vehicle — and by the time IPRs existed, the patent had already expired.

Family note (relevant to any assertion you may be facing)

The '190 patent is the parent of a continuation, US 4,827,888 ("Nozzle"), filed 1988-04-21 as a continuation of application 06/868,938 and granted 1989-05-09. See Google Patents family view. It shares the 1986-05-30 priority date and therefore also expired in 2006. No PTAB proceeding of any type appears on file against the '888 patent either. If an assertion letter cites the '888 patent, the same analysis applies.

Strategic summary

Claim status: all 21 claims are UNTESTED at the PTAB, and all 21 are expired. Claims 1–8 (the Y-shaped single-outlet nozzle with an isolated tubular fuel line terminating adjacent the output port), claims 9–15 (the multi-member housing/nozzle variant with the low-pressure-draw limitation), and claims 16–21 (the carburetor-mount two-groove plate embodiment) have never been construed by the Board, never been the subject of an institution decision, and never been canceled or confirmed in an AIA trial. There is no narrowing IPR history to work from, and symmetrically, no Board precedent constraining how a district court would read "terminating adjacent to said output port," "isolated from said cavity," or the 3–12 PSI / 500–1000 PSI ranges. I found no ex parte reexamination, no reissue, and no certificate of correction affecting claim scope either.

Estoppel landscape: there is none, because there is no proceeding to trigger it. 35 U.S.C. § 315(e)(2) estoppel attaches only to a petitioner that reaches a final written decision. With zero IPRs, no party is estopped from anything, and no prior art has been "reasonably raised" or foreclosed at the Board. If you nevertheless needed to attack validity — which you almost certainly do not, given expiry — the full universe of § 102/§ 103 art remains available in district court or the PTAB, subject only to the ordinary § 282(b) invalidity defenses. Note the irony: the same freedom from IPR estoppel is what makes this patent useless to a plaintiff, because the expiry dates mean there is no infringement occurring within the § 286 six-year damages lookback window (2006-05-30 + 6 years = 2012-05-30, itself long past).

Pattern signals: not applicable, and that itself is informative. There is no repeat petitioner (no petitioner at all), no patent-owner appeal activity (nothing to appeal), and no sign of a defensive aggregator such as Unified Patents or RPX targeting this patent. That is the expected profile for a patent whose remaining life ended in 2006. The stronger signal is the flip side: well-asserted, economically live patents reliably attract IPRs, and the AIA era began only after this patent's expiry. The absence of PTAB activity here does not mean the claims were tested and survived — it means nobody had an economic reason to try. Treat any assertion of the '190 or '888 patent as a red flag about the sender's candor, not as evidence of a hardened patent.

Recommended next steps

• Demand letter citing US 4,798,190: check the date of the accused conduct first. The patent expired 2006-05-30. There is no actionable infringement for any act on or after that date, and no damages for pre-expiration conduct remain recoverable given the six-year limit in § 286. The Google Patents legal-status entry ("Expired - Lifetime", anticipated expiration 2006-05-30) is your first citation: https://patents.google.com/patent/US4798190/en.
• Verify the absence of proceedings yourself before relying on it. The ODP ingest can lag. Run the patent number through the PTAB API / PTAB Center and PTAB E2E:
  • USPTO PTAB Center search: https://ptacts.uspto.gov/ptacts/
  • PTAB E2E (trial documents, institution decisions, FWDs): https://ptab.uspto.gov/
  • Published PTAB decisions: https://www.uspto.gov/patents/ptab/decisions
  • CourtListener docket sweep for "4798190": https://www.courtlistener.com/?q=%224798190%22
• If a proceeding does exist that ODP hasn't indexed, the standard IPR milestones would govern it: institution decision within 6 months of the petition's filing, trial completed and FWD issued within 12 months of institution (extendable up to 6 months for good cause under § 316(a)(11)). I have no dates to give you, because I found no petition. Flag anything you locate and I will work it up claim by claim.
• If no proceeding exists — which is the current state — say so plainly in any invalidity or non-infringement position. Do not dress the silence up as a PTAB win. The accurate statement is: "The '190 and '888 patents expired 2006-05-30; no AIA trial proceeding, reexamination, or reissue ever challenged them; the claims stand unadjudicated but unenforceable as to any post-2006 conduct."

Confidence note: I am highly confident that PGR and CBM are legally unavailable for this patent and that the term expired in 2006. I am reasonably but not absolutely confident that no IPR petition was ever filed, because that conclusion rests on the ODP block being current plus negative web-search results; a late-filed or poorly indexed petition could theoretically have escaped both. Verify via PTAB E2E before filing anything that depends on the "no IPR" fact.

I'll verify what I can from live sources before reconstructing the chain, since the fetched Google Patents text includes reel/frame numbers but not the correspondent-of-record field.

Let me check the corporate history and any litigation/enforcement activity.

Ownership & Assignment Reconstruction — US 4,798,190 ("Nozzle")

Sources: Google Patents legal-events record for US4798190A (fetched 2026-09-24); USPTO Assignment Center (https://assignmentcenter.uspto.gov/); SEC/EDGAR filings for Holley Performance Products and successors. Note on scope: the fetched legal-events record supplies reel/frame, conveyance type, assignor/assignee and execution/recording dates, but not the correspondent-of-record field. I could not retrieve correspondent names for this chain and flag that gap explicitly below rather than guessing.

Inventors

Pattern: Both named inventors were the co-founders of the assignee — Vaznaian and Thermos reportedly established Nitrous Oxide Systems, Inc. in 1978 (per a published conference history of NOS). So this is not a case of employee-inventors later departing a corporate assignee; the inventors were the company. The assignment to NOS was executed 1986-05-29, one day before the 1986-05-30 filing date, and recorded the same day — a routine founder-to-company assignment, not evidence of a pre-fire-sale departure.

I found no evidence that either inventor left NOS within 12 months of filing, and (consistent with them being founders) no secondary assignment by either inventor to any third party is recorded.

Original assignee

• Entity on the face of the patent: Nitrous Oxide Systems, Inc., 5930 Lakeshire Drive, Cypress, CA 90630 (a California corporation). Confirmed independently by the DOE/OSTI record and by Google Patents' "Original Assignee" field.
• Product embodied the claims: Yes. NOS manufactured and sold nitrous-oxide injection systems and the Y-shaped / plate-style nozzles described in the claims. The patent's commercial embodiment is the classic "NOS nozzle" used in nitrous plate and direct-port kits.
• Line of business: Aftermarket high-performance automotive fuel/nitrous systems.
• Current status: Operating as a brand within a larger group. Holley Performance acquired NOS in the late 1990s (Holley's holdcos were purchased by KHPP Acquisition Corp. effective May 15, 1998). NOS has since passed through successive sponsor owners — Monomoy Capital Partners (2012), Lincolnshire Management (2013), Sentinel Capital Partners (2018 platform) — and is today a brand of Holley Inc. (NYSE: HLLY), Bowling Green, KY, whose 10-Ks list "nitrous oxide injection systems" among its core products. NOS, Inc. remains a named grantor of record in the 2010 and 2018 lien filings, i.e., a live subsidiary of the Holley group.

Assignment timeline

The critical structural finding: only the 1986 assignment conveys title. Every subsequent record is a security interest (lien) or its release/termination. No post-issuance assignment of the patent to an IP-holding, licensing or assertion entity appears anywhere in the record.

• 1986-05-29 (executed) / recorded 1986-05-30 — Reel 004606/0119

  • Conveyance: Assignment (ASSIGNMENT OF ASSIGNORS INTEREST)
  • Assignor: Dale L. Vaznaian and Michael J. Thermos (individually)
  • Assignee: Nitrous Oxide Systems, Inc.
  • Correspondent: not disclosed in the fetched record (1986-era filing attorney; undeterminable from available sources)
  • Context: Founder-to-company assignment, executed one day pre-filing.

• 2001-06-01 (eff.) / recorded 2001-10-12 — Reel 012219/0930

  • Conveyance: Security Interest (grant of security)
  • Assignor: Nitrous Oxide Systems, Inc.
  • Assignee: Fleet Capital Corporation (Illinois)
  • Correspondent: not disclosed in the fetched record
  • Context: Securitization — lender lien supporting the 1998 KHPP/Holley buyout financing.

• 2002-07-30 (eff.) / recorded 2002-09-11 — Reel 013081/0180

  • Conveyance: Termination of Security Interest
  • Assignor: Fleet Capital Corporation
  • Assignees: Holley Performance Products, Inc.; Nitrous Oxide Systems, Inc.; Earl's Supply Company
  • Correspondent: not disclosed in the fetched record
  • Context: Lien release on refinancing — confirms NOS was by then inside the Holley corporate fold.

• 2006-01-26 (eff.) / recorded 2006-02-02 — Reel 017105/0764

  • Conveyance: Security Agreement
  • Assignors: Holley Performance Products Inc.; Holley Performance Systems, Inc.; Weiand Automotive Industries, Inc. — and others (i.e., the Holley obligor group, incl. NOS)
  • Assignee: U.S. Bank National Association (Massachusetts)
  • Correspondent: not disclosed in the fetched record
  • Context: Securitization — blanket lien over the Holley group's IP, including this patent.

• 2009-07-01 (exec.) / recorded 2009-07-01 — Reel 022902/0601

  • Conveyance: Security Agreement
  • Assignor: Holley Performance Products, Inc.
  • Assignee: Wells Fargo Foothill, Inc., as Agent
  • Correspondent: not disclosed in the fetched record
  • Context: Securitization — replacement/refinancing lien on Holley IP.

• 2010-06-22 (eff.) / recorded 2010-06-28 — Reel 024599/0236

  • Conveyance: Release of Security Interest (expressly releasing Reel 17105/0764)
  • Assignor: U.S. Bank National Association
  • Assignees: Holley Performance Products Inc.; Holley Performance Systems, Inc.; Weiand Automotive Industries, Inc.; Nitrous Oxide Systems, Inc.; Holley Performance Products Holdings, Inc.
  • Correspondent: not disclosed in the fetched record
  • Context: Lien release — discharge of the 2006 U.S. Bank security agreement.

• 2018-10-26 (eff.) / recorded 2018-11-06 — Reel 047429/0343 (corrected by Reel 048475/0125, recorded 2018-11-18)

  • Conveyance: Security Interest
  • Assignors: Flowmaster, Inc.; APR, LLC; Accel Performance Group LLC — and others (the Sentinel-era Holley obligor group)
  • Assignee: UBS AG, Stamford Branch, as Collateral Agent (first lien)
  • Correspondent: not disclosed in the fetched record
  • Context: Securitization — first-lien financing for the 2018 Sentinel Capital Partners platform acquisition.

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

  • Conveyance: Security Interest (second lien)
  • Assignors: Flowmaster, Inc.; APR, LLC; Accel Performance Group LLC — and others
  • Assignee: AEA Debt Management LP, Second Lien Collateral Agent
  • Correspondent: not disclosed in the fetched record
  • Context: Securitization — paired second-lien facility on the same collateral pool.

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

  • Conveyance: Release by Secured Party
  • Assignor: AEA Debt Management LP, as Second Lien Collateral Agent
  • Assignees: High Performance Industries, Inc.; Holley Performance Systems, Inc.; Holley Performance Products Inc.; Racepak LLC; Powerteq LLC; MSD LLC; Accel Performance Group LLC; APR, LLC; Flowmaster, Inc.
  • Correspondent: not disclosed in the fetched record
  • Context: Lien release on the 2021 recapitalization (release of the 2018 second lien).

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

  • Conveyance: Release by Secured Party
  • Assignor: UBS AG, Stamford Branch, as First Lien Collateral Agent
  • Assignees: same obligor group as above
  • Correspondent: not disclosed in the fetched record
  • Context: Lien release — discharge of the 2018 first lien, completing the 2021 refinancing.

Companion filing note: the continuation US 4,827,888 (application 07/184,334, filed 1988-04-21, issued 1989-05-09) claims priority to the same 1986-05-30 filing and is likewise credited to Nitrous Oxide Systems, Inc. Any portfolio-level analysis of this family should read the two patents together.

Timeline diagram

timeline
    title Ownership of US 4798190
    1986 : Filed 30 May by Nitrous Oxide Systems
         : Inventors assign rights to NOS
    1989 : Patent issued 17 January
    2001 : Security interest to Fleet Capital
    2002 : Fleet Capital lien terminated
    2006 : US Bank security agreement recorded
         : Patent term expires 30 May
    2009 : Wells Fargo Foothill lien
    2010 : US Bank lien released
    2018 : UBS first lien recorded
         : AEA second lien recorded
    2021 : UBS lien released
         : AEA lien released

NPE / troll-pattern signals

1. Shell-entity transfer — not present. No assignment of this patent to any "IP / Licensing / Holdings / Ventures" entity exists in the record. The chain terminates at Nitrous Oxide Systems, Inc., a named grantor (not grantee) on the lien filings and an operating Holley subsidiary. Reels 004606/0119 (the only title transfer), 024599/0236, 047429/0343, 048147/0510.

2. Known asserter in the chain — not present. No assignee matches Acacia, Marathon, IV, IPNav, Wi-LAN/Conversant, Vringo, Pendrell, Round Rock, Erich Spangenberg entities, or any Unified Patents / RPX high-frequency-plaintiff flag. Assignees are NOS, Holley and secured lenders (Fleet Capital, U.S. Bank, Wells Fargo Foothill, UBS, AEA Debt Management LP). None are NPE assertion vehicles.

3. Repeat correspondent across the chain — unclear (could not be assessed). The Assignment Center correspondent-of-record field was not returned in the fetched legal-events data, and I did not independently retrieve it. There is therefore no basis to identify a recurring recording attorney or firm. This is a data gap, not a negative finding — do not read it as "no repeat correspondent."

4. Cascading transfers — not present. The 2001→2021 records are lender liens tied to successive sponsor recapitalizations (KHPP 1998, Monomoy 2012, Lincolnshire 2013, Sentinel 2018), not chained single-purpose LLCs. Several records cover the same obligor group rather than successive different owners; the borrower group names recur (e.g., Holley/NOS on Reels 017105/0764 and 024599/0236), which is the opposite of a shell cascade.

5. Pre-litigation transfer — not present. No infringement suit naming US 4,798,190 was identified, and the patent expired 2006-05-30 — so a litigation-motivated transfer is temporally impossible for the post-2006 record.

6. Bankruptcy fire-sale — not present in the assignment record. No Chapter 7/11 sale of this patent appears. The lien-and-release cadence (2001, 2006, 2009, 2018, 2021) is consistent with leveraged-buyout and recapitalization financing at Holley, not with a distressed asset sale.

7. Privateering — not present. No operating-to-NPE transfer, and no SEC filing or third-party coverage surfaces NOS/Holley funding assertions against competitors via a proxy.

8. Defensive aggregator (anti-NPE) — not present. The chain does not terminate at RPX, AST, LOT, Unified Patents or OIN. Ownership stayed with the operating group and the patent lapsed for failure to reach end-of-term, not transfer.

Verdict

Insufficient data — in the specific sense that the record contains only the original assignment of title (Reel 004606/0119, executed 1986-05-29) and no subsequent conveyance: every later entry (Reels 012219/0930, 013081/0180, 017105/0764, 022902/0601, 024599/0236, 047429/0343, 048147/0510, 058944/0279, 058948/0926) is a security interest or its release, not a transfer of ownership.

This is not an NPE chain. Title never left the operating company: the patent was assigned by its founding inventors to Nitrous Oxide Systems, Inc. and has remained within the NOS/Holley group (now Holley Inc., NYSE: HLLY) throughout, with the repeated liens merely financing successive sponsor buyouts. The patent expired 2006-05-30 (anticipated expiration recorded 2006-05-30), so it cannot support any present assertion. The single unverified item is the correspondent of record, which I flag as an open data gap rather than a finding.

Verify at: https://assignmentcenter.uspto.gov/ (search patent number 4798190) and https://patents.google.com/patent/US4798190/en.

I'll research each cited prior-art reference for US 4,798,190. Let me start with parallel searches on the key references.

Let me research the remaining cited references.

Prior Art Analysis — U.S. Patent No. 4,798,190 ("Nozzle")

0. Scope, method, and a threshold caveat

Patent under analysis: U.S. 4,798,190 A — "Nozzle." Inventors Dale L. Vaznaian and Michael J. Thermos; assignee Nitrous Oxide Systems, Inc. (Cypress, CA). Filed 1986‑05‑30; granted 1989‑01‑17. Status: Expired – Lifetime (anticipated expiration 2006‑05‑30). A continuation, U.S. 4,827,888 A (application 07/184,334, filed 1988‑04‑21), shares the same priority.

Important methodological point on your request. You asked which claims each reference "potentially anticipates under 35 U.S.C. § 102." Anticipation under § 102 requires that a single reference disclose every element of the claim as arranged in the claim. On the record here, the examiner cited these nine references as background/art in the field; most are far more naturally § 103 (obviousness) references than § 102 (anticipation) references. I therefore report each reference's content and then state, per claim, whether true § 102 anticipation is plausible or whether the reference is really an obviousness-type teaching. I do not overstate any reference as an anticipatory art where the elements do not line up. Where I say a reference "anticipates," I mean the elements map closely and warrant a § 102 argument; where I say it is a § 103 reference, I mean no single-reference disclosure of the full claim.

Critical distinguishing feature of the '190 claims (used throughout): The asserted novelty is a coaxial "tube-in-tube" architecture in which (i) a tubular fuel line runs inside a cavity/housing that carries the high-pressure oxidizer, (ii) the fuel is isolated from the cavity until it reaches the output port, and (iii) the high-pressure oxidizer exiting past the open end of the fuel line creates a low-pressure (venturi/vacuum) region that draws the fuel out and atomizes it. This appears in independent claims 1, 9, 13, and 16, with dependent claims adding pressure ranges (claims 4, 5, 10, 11, 18, 19), phase change of the N₂O (claims 3, 6, 17, 20), multiple outlets/fuel lines (claims 7, 8, 12, 15), threads (claim 14), and a mounting bore (claim 21).

1. The nine examiner-cited references

Citations verified from the patent's own "Patent Citations (9)" table; content verified by web retrieval where available. Confidence on each is noted.

1.1 US 622,482 A — "Benjamin f" (title garbled in the record)

• Citation: US 622,482 A. Publication date 1899‑04‑04. Inventor field appears simply as "Benjamin f"; no substantive title is given in the Google Patents citation table.
• Description: The record supplies no title, abstract, or claim text. This is the oldest reference in the list and, given the 1899 date and the garbled bibliographic data, is almost certainly a minor/ancillary mechanical antecedent (a spray/atomizing or carbureting device) rather than a nitrous-oxide injection system. I could not verify its subject matter with confidence. ⚠️ Flag: I am not fabricating a description; the available record does not state what this patent discloses.
• § 102 relevance: Cannot be assessed on the available record. If it is a fuel-atomizing or aspirating nozzle, it would at most be a § 103 background reference against the general concept of drawing one fluid with another, not an anticipatory reference against any claim.

1.2 US 1,627,727 A — James A. Charter, "Constant-compression internal-combustion engine"

• Citation: US 1,627,727 A. Filed 1923‑01‑29; published 1927‑05‑10. Inventor James A. Charter.
• Description: A constant-compression internal-combustion engine. It is an engine-cycle reference, not a fuel/oxidizer injector.
• § 102 relevance: No anticipation of any claim. It does not disclose a dual-input nozzle, a fuel line inside an oxidizer cavity, or venturi fuel draw. Background art only.

1.3 US 2,482,864 A — Margaret Nemnich, "Liquid fuel carburetor"

• Citation: US 2,482,864 A. Filed 1944‑12‑01; published 1949‑09‑27. Inventor Margaret Nemnich.
• Description: A liquid-fuel carburetor (fuel/air mixing device). Teaches mixing a liquid fuel with an air stream in a carbureting structure.
• § 102 relevance: No anticipation. It is carburetion art — arguably relevant to the general objective of mixing/atomizing fuel, i.e., a § 103 background reference. It discloses neither a coaxial fuel line inside an oxidizer cavity nor a high-pressure-oxidizer vacuum draw of the kind recited in claims 1, 9, 13, or 16.

1.4 US 3,182,646 A — Kuechenmeister (Craig Alfred), "Air-bled coaxial injector"

• Citation: US 3,182,646 A. Filed 1961‑06‑15; published 1965‑05‑11. Inventor Kuechenmeister Craig Alfred (recorded as "Kuechenmeister Craig Alfred").
• Description: An air-bled coaxial injector — i.e., a coaxial (tube-within-tube) injector geometry in which one fluid is introduced through an inner passage and a second fluid through an annular passage around it. (I confirmed the title and dates; I was not able to retrieve the full specification text before my search budget was exhausted, so the internal-detail description is based on the title and the coaxial-injector art class.) ⚠️ Flag: full-text not retrieved.
• § 102 relevance: The most structurally pertinent reference, but still not a clean § 102 anticipation. Because it is a coaxial injector, it is the closest art to the "fuel line inside a cavity/housing" limitation of claims 1, 9, 13, and 16. However:
  • There is no indication it uses nitrous oxide as the annular high-pressure oxidizing agent drawing low-pressure fuel via a venturi (claims 3, 5, 6, 9, 11, 13).
  • There is no indication of the specific 3–12 PSI fuel / 500–1000 PSI oxidizer ranges (claims 4, 5, 10, 11, 13, 18, 19).
  • It does not disclose the two-section housing with concentric grooves of claim 16.
  • Accordingly it is best treated as a § 103 reference supporting the coaxial-fuel-line concept, combined with the Ram Automotive nitrous-oxide art (§§1.8–1.9 below). A § 102 argument against claim 1 or 9 would be a stretch and would likely fail for want of the oxidizer-draw and pressure-range limitations.

1.5 US 3,610,213 A — Giovanni Gianini, "Fuel injection system"

• Citation: US 3,610,213 A. Filed 1970‑03‑09; published 1971‑10‑05. Inventor Giovanni Gianini.
• Description: A fuel injection system. (Title and dates confirmed from the '190 citation table and cross-references; full specification not retrieved in this session.) ⚠️ Flag: full-text not retrieved.
• § 102 relevance: Generally a background/§ 103 reference. A conventional fuel-injection system does not, on the record available, disclose the isolating fuel-line-in-oxidizer-cavity structure or the nitrous-oxide vacuum draw. No claim is anticipated.

1.6 US 4,157,084 A — Marvin E. Wallis, "Fuel injection system and method for internal combustion engine"

• Citation: US 4,157,084 A. Filed 1977‑09‑20; published 1979‑06‑05. Inventor Marvin E. Wallis. (Confirmed via Google Patents and the USPTO PDF.)
• Description (verified): A fuel-injection/startup-assist system in which pressurized air flows through a mixing chamber (a Venturi throat) and low-pressure fuel is drawn into and mixed with the pressurized air stream by the pressure differential at the throat, then delivered through an injector valve into the intake manifold. A stated object is to avoid the conventional high-pressure fuel pump and to produce a "highly combustible, atomized" fuel/air mixture; the fuel can be supplied by a low-pressure pump and is drawn into the air flow by the Venturi differential.
• § 102 relevance — this is the most legally interesting of the older references:
  • Wallis discloses the core operating principle relied on in claims 1, 9, 13, and 16: a low-pressure fuel drawn into and atomized by a high-velocity gas stream using a pressure differential/Venturi effect. This directly reads on the functional language of claim 9 ("creating a low pressure at said termination of said fuel line so as to draw said fuel… to mix") and the analogous language in claims 1 and 13.
  • However, it does not anticipate, because:
    • The pressurized gas is air, not nitrous oxide as the oxidizer (claims 3, 6, 11, 13, 17, 19, 20 unaddressed).
    • It does not teach the coaxial tube-in-tube isolation structure where the fuel line is disposed within the oxidizer cavity and the fuel is isolated from that cavity until the outlet (claims 1, 9, 13). Its fuel is delivered into an air stream in a mixing chamber, not carried enclosed within a housing that also contains the air.
    • It does not teach the specific 500–1000 PSI nitrous-oxide / 3–12 PSI fuel ranges.
  • Conclusion: Wallis is a strong § 103 reference (and a plausible § 102 reference against the functional claim language in isolation, but not against the full structural claims as written). It is the reference most worth pressing on the "venturi draws and atomizes low-pressure fuel" concept.

1.7 US 4,211,200 A — Audi NSU Auto Union AG, "Vacuum force amplifier for internal combustion engine"

• Citation: US 4,211,200 A. Filed 1977‑04‑21 (per the 4798190 table); published 1980‑07‑08. Assignee Audi Nsu Auto Union Aktiengesellschaft. (Note: one source lists the filing date as 1978‑04‑18 for application 05/897,417; the '190 citation table lists 1977‑04‑21. I flag this minor discrepancy and use the '190 table's date, since the '190 record is authoritative here.)
• Description (verified): An internal-combustion-engine vacuum-amplifier using an injector-type jet pump (essentially a Venturi/ejector) in the idle circuit. The jet pump has a high-pressure input, a low-pressure input, and an output; the pressure differential draws suction and drives a vacuum-actuated auxiliary device (e.g., power brakes).
• § 102 relevance: § 103 background reference, not an anticipation. It teaches a jet pump/ejector — the same physics (a high-pressure stream entraining a second fluid and drawing it via a low-pressure region) that underlies the '190 vacuum-draw mechanism. But it is a vacuum accessory device, not a fuel/oxidizer injection nozzle; it does not disclose fuel, nitrous oxide, the coaxial isolated fuel line, the pressure ranges, or the two-part grooved housing. It supports an obviousness argument that using an ejector to draw a second fluid was known, but anticipates no claim.

1.8 US 4,494,488 A — Ram Automotive Company, "Fuel charging system for high performance vehicles"

• Citation: US 4,494,488 A. Filed 1984‑05‑23; published 1985‑01‑22. Assignee Ram Automotive Company (Canton, OH). (Verified via Google Patents, FPO, and the USPTO PDF.)
• Description (verified): A nitrous-oxide "cheater" system for racing engines. A supply cylinder of liquid nitrous oxide at ~900 PSI is connected by a supply line to a spray bar mounted on a base plate between the carburetor and intake manifold; additional fuel is injected simultaneously through a separate fuel spray bar. A nitrogen-gas blanket maintains nitrous-oxide pressure. Critically, the nitrous oxide and fuel are delivered through two separate spray bars ("spaced with respect to… nitrous oxide spray bar 43"), and the patent expressly notes the prior-art approach of injecting nitrous oxide and additional fuel simultaneously into the engine.
• § 102 relevance: The best § 103 reference in the set and central to the '190 background. It discloses the problem the '190 solves — separately injected nitrous oxide and fuel, i.e., the "two-nozzle" arrangement the '190 specification criticizes for puddled fuel. It does not disclose a single coaxial nozzle with a fuel line inside an oxidizer cavity, nor the venturi draw, nor the pressure ranges. So it anticipates no claim, but it is highly relevant:
  • As § 103 art, it supplies the motivation (poor mixing in the two-spray-bar system) and the nitrous-oxide/fuel injection context that would be combined with a coaxial injector (US 3,182,646) and/or a Venturi-draw injector (US 4,157,084) to reach claims 1, 9, and 13.
  • Its disclosure of ~900 PSI liquid nitrous oxide is close to, but not identical to, the claimed 500–1000 PSI range (claims 5, 11, 13, 19) — relevant to § 103, not a § 102 anticipation of a claimed range.

1.9 US 4,572,140 A — Ram Automotive Company, "Nitrous oxide precooler"

• Citation: US 4,572,140 A. Filed 1984‑10‑09; published 1986‑02‑25. Assignee Ram Automotive Company (Canton, OH). (Verified via Google Patents, Justia, and OSTI.)
• Description (verified): A nitrous-oxide precooler for a fuel-charging system. Liquid nitrous oxide at ~900 PSI flows through a delivery conduit surrounded by a jacket (silicone hose) forming a cooling chamber. Gaseous nitrous oxide is purged from the delivery conduit and expanded in the cooling chamber, which cools the liquid nitrous oxide and keeps it in liquid form before it is injected through a solenoid valve into the spray bar. Fuel is delivered through a separate spray bar and mixed with the nitrous oxide downstream.
• § 102 relevance: § 103 background reference; anticipates no claim. Its relevance to the '190 is:
  • It confirms the state of the art of a conduit running inside a larger outer chamber — structurally analogous to, but functionally different from, the '190's fuel-line-inside-oxidizer-cavity (the Ram jacket carries coolant/expanding vapor; the '190 cavity carries the pressurized oxidizer). This supports a § 103 argument about the general familiarity of coaxial tube-and-chamber constructions.
  • It again shows the two-spray-bar nitrous-oxide/fuel paradigm, reinforcing the motivation to improve mixing.
  • It contains no fuel-line-in-oxidizer-cavity nozzle and no venturi fuel draw.

2. Consolidated claim-mapping table

3. Bottom line

• No single cited reference anticipates any claim of U.S. 4,798,190 under § 102. The examiner's citations are field/background art. The claimed combination — a coaxial, tube-in-tube nozzle in which an isolated low-pressure fuel line runs inside a cavity carrying high-pressure nitrous oxide, which is discharged past the fuel-line mouth to create a venturi vacuum and atomize the fuel — is not disclosed in full by any one of the nine references.
• The strongest references for a § 103 challenge (were the patent still in force, which it is not — expired 2006):
  1. US 3,182,646 (Kuechenmeister) — coaxial injector structure (claims 1, 9, 13).
  2. US 4,157,084 (Wallis) — Venturi/low-pressure-differential draw and atomization of low-pressure fuel (claims 1, 9, 13 functional language).
  3. US 4,494,488 and US 4,572,140 (Ram Automotive) — the nitrous-oxide high-pressure/fuel low-pressure context, the two-spray-bar problem supplying motivation, and the ~900 PSI N₂O figure (claims 3–6, 10–11, 13, 17–20).
     A combination of Kuechenmeister + Wallis + Ram Automotive would be the natural obviousness attack.
• US 1,627,727, US 2,482,864, US 3,610,213, US 4,211,200, and US 622,482 A are weaker: engine-cycle, carburetion, generic fuel-injection, and jet-pump/vacuum-accessory art respectively. They round out the field but do not by themselves reach the claims.

Verification status (honesty flags)

• Fully verified by retrieval this session: US 4,494,488; US 4,572,140; US 4,211,200; US 4,157,084.
• Verified as to title/dates, full text not retrieved: US 3,182,646 (coaxial injector); US 3,610,213; US 1,627,727; US 2,482,864.
• Not verifiable from the record (do not treat the description as confirmed): US 622,482 A — the citation table supplies only "Benjamin f" as the inventor and no title; I have not fabricated a subject-matter description for it.
• Bibliographic discrepancy flagged: US 4,211,200 filing date is given as 1977‑04‑21 in the '190 table but as 1978‑04‑18 in one external listing; I used the '190 table date as authoritative for this analysis.

Because the patent expired 2006‑05‑30, none of this prior art has ongoing invalidity/enforcement significance; the analysis is of historical/defensive interest only.

I'll research the cited prior-art references to ground the obviousness analysis.

Let me get details on the remaining cited references and the key coaxial-injector art.

Obviousness Analysis — U.S. Patent No. 4,798,190 ("Nozzle") under 35 U.S.C. § 103

Scope note. This section builds on the claim mapping, bibliographic data, and "no known litigation" finding already generated, and does not repeat them. All analysis below is grounded in (a) the authoritative full text of US 4,798,190 (Google Patents, https://patents.google.com/patent/US4798190/en), and (b) the nine references listed in that page's "Patent Citations (9)" block — i.e., the prior art of record — together with the text I was able to retrieve for several of them. I flag explicitly where I could not retrieve a reference's full text and therefore reason only from its title, date, assignee, and claim-mapping logic.

1. The § 103 legal frame

Under 35 U.S.C. § 103 (as construed by Graham v. John Deere and KSR Int'l v. Teleflex), the question is whether the claimed subject matter as a whole would have been obvious to a person having ordinary skill in the art ("POSITA") at the May 30, 1986 filing date. The four Graham factors:

1. Scope and content of the prior art
2. Differences between the prior art and the claims
3. Level of ordinary skill — here, a mechanically competent fuel-system/nozzle engineer working in the automotive aftermarket "power adder" (nitrous-oxide) field circa 1986
4. Objective indicia (secondary considerations)

KSR supplies the motivation-to-combine doctrine: a combination is obvious where (i) the elements were known, (ii) there was a known problem for which the combination was an obvious solution, and (iii) the combination yields only predictable results — including "the mere duplication of parts," "a predictable variation," and the "obvious to try" standard where there are a finite number of identified, predictable solutions. No express teaching of the exact combination is required; the motivation may come from "market forces," "design incentives," or "common sense."

2. Scope and content of the prior art of record

Each of the nine examiner-cited references predates the 1986-05-30 filing date and thus qualifies under at least § 102(a)/(b); the 1977–1985 items are § 102(b) art.

⚠️ Important qualification on the "Cited By (48/73)" lists on the same page. Those are documents that cite '190 — i.e., they post-date 1986 (earliest 1988) and therefore are not prior art against '190 under § 102/§ 103. They are usable only as background evidence of the field's state of the art after the invention, and can be relevant to secondary considerations or claim construction — not as § 103 references. Any obviousness case must therefore rest on the nine examiner-cited items above.

3. The inventive core to be tested

From the previously generated claim mapping, the independent claims reduce to a small number of limitations that are actually doing the work:

• The coaxial "tube-in-cavity" architecture (claim 1): a housing with two inlets and an outlet; a cavity running from the oxidizer inlet to the outlet; and a tubular fuel line connected to the fuel inlet whose free end stops adjacent the outlet, such that fuel is "isolated from said cavity" until it exits.
• The aspiration/Venturi function (claim 9): high-pressure nitrous exiting the output creates low pressure at the fuel line's termination, drawing fuel out and mixing it with the oxidizer at the exit.
• The numerical pressure relationship (claims 4, 5, 10, 11, 13, 18, 19): nitrous at ~500–1000 psi; fuel at ~3–12 psi.
• The oxidizer phase change (claims 3, 17, 20): liquid nitrous converting to gas "upon entering said device," with its attendant cooling of the fuel line (spec: "The vaporization serves to cool the fuel line within the nozzle").
• The plate/sandwich embodiment (claims 16–21): top member with a first groove (fuel manifold), bottom member with a second groove (nitrous manifold), a third inlet port linking the grooves, an outlet port on the nitrous groove, a fuel line in each third port, and a central mounting bore 21 for the carburetor air-cleaner stud.

4. Primary combination rendering claim 1 obvious

Primary reference: US 3,182,646 (Kuechenmeister), "Air-bled coaxial injector."

A "coaxial injector" is the name of a specific, well-known genus in fluid-injection engineering: an inner tube coaxial with an outer annular passage, with both fluids discharging at a common mouth and mixing only at/after the discharge plane. This is precisely the geometry of claim 1:

• two input ports (inner-passage inlet + outer-passage inlet) → one output port;
• an outer passage = the claimed "cavity" extending from the first (oxidizer) inlet to the outlet;
• an inner tube = the claimed "tubular fuel line" connected at one end to the second inlet and terminating adjacent the outlet;
• because the fluids are physically separated by the tube wall, the fuel is, by construction, "isolated from said cavity."

If Kuechenmeister's inner tube carries the fuel and the annulus carries the combustion air (the ordinary arrangement in air-assist/air-bled injectors of that era), then claim 1's apparatus structure is met, and the only remaining gap is that the second fluid is air rather than nitrous oxide delivered as an oxidizing agent at substantially greater pressure than the fuel.

Secondary reference to close that gap: US 4,494,488 (Ram Automotive), alone or with US 4,572,140 (Ram Automotive).

• Ram '488 expressly discloses nitrous oxide at ~900 psi fed through a delivery system, a fuel supply at ordinary low carburetor pressure via a separate fuel bar 46, and — critically — a tube-within-a-bore mechanical arrangement (pickup tube 48 inside axial bore 18 forming annular space 51) plus a base plate 41 sandwiched between carburetor and intake manifold.
• Ram '140 expressly discloses liquid nitrous oxide in a conduit surrounded by an annular chamber, and relies on nitrous vaporization for thermal management of that conduit.

Gianini (US 3,610,213) supplies the functional/aspiration teaching for claim 9 (and for the vacuum-draw language in the '190 specification): a high-pressure gas jet issuing into a passage "[carries] away all the fuel collected" and does so in part by "the suction generated near the outlet orifice." That is the venturi-draw mechanism the '190 claims as its novelty.

Element-by-element result for claims 1 and 9

5. Motivation to combine (the KSR analysis)

The obviousness case does not depend on an express "combine these references" statement; the motivation arises from the field itself:

1. Same field of endeavor and same problem. All three Ram references, Kuechenmeister, Gianini, and Wallis are directed to delivering and mixing fuel (and, in Ram's case, nitrous oxide) into an IC engine intake. The '190 specification itself states the problem: with "a separate nitrous oxide nozzle and fuel nozzle," the low-pressure fuel "is injected in the form of a stream that is splattered about the manifold and will puddle … and will therefore be very difficult to ignite." Ram '488 embodies exactly that prior-art arrangement (separate spray bars 43 and 46). A POSITA facing the recognized puddling/atomization problem in a nitrous system would look directly at the known single-body coaxial injector for a solution.

2. The combination was "obvious to try" over a finite, predictable set. By 1986 the art recognized essentially two ways to make a two-fluid injector: (a) separate nozzles (Ram '488), and (b) a coaxial/annular injector discharging the two fluids at a common mouth (Kuechenmeister). Choosing (b) over (a) to fix mixing is a "finite number of identified, predictable solutions" — the KSR paradigm.

3. Predictable result. Keeping two fluids in nested passages until a common discharge inherently prevents the fuel from contacting the oxidizer inside the device (the claimed "isolated from said cavity" limitation) and inherently causes the faster, higher-pressure stream to shear and entrain the slower one at the exit. Nothing unpredictable occurs in substituting nitrous oxide for the air of Kuechenmeister: nitrous is a liquefied gas oxidizer, and Ram '140 already taught that it flashes to vapor and cools the surrounding hardware — a property that, as the '190 spec notes, conveniently "serves to cool the fuel line within the nozzle."

4. Design incentive / market forces. The Ram references show a commercially active, competitive field (high-performance/racing nitrous systems) in which improved fuel atomization translates directly to power. That is the classic "market demand" motivation expressly recognized in KSR.

5. The mechanical elements were all individually known. A tube-in-bore (Ram '488); an annular chamber about a nitrous conduit (Ram '140); a gas-jet aspirating a liquid (Gianini); and vacuum amplification by a pressure differential (Audi NSU '200). The '190 claim combines them for their known purposes, producing no more than their predictable aggregate.

6. Dependent claims

Assuming the independent claims are obvious, the dependents fall with them, and each adds only known or conventional matter:

• Claims 2 (cylindrical cavity) — a predictable shape choice; tube-in-bore geometry is naturally cylindrical (Ram '488).
• Claims 3, 6, 17, 20 (liquid vs. gaseous nitrous; phase change on entry) — taught by Ram '140 (liquid nitrous, vaporization) and inherent in any high-pressure liquefied-gas line.
• Claims 4, 5, 10, 11, 18, 19 (3–12 psi fuel; 500–1000 psi nitrous) — the nitrous range is squarely Ram '488/'140 (~900 psi); the fuel range is the standard low-pressure carburetor fuel pressure and is a result-effective variable long known in the art. Enlarging a disclosed range to encompass an art-recognized optimum is generally obvious (In re Peterson / In re Boesch rationale).
• Claims 7, 8, 12, 15 (plural output ports; plural fuel lines) — "mere duplication of parts," a canonical KSR example of predictable variation; and a natural adaptation to multi-barrel/multi-cylinder engines (the '190 spec contemplates exactly this).
• Claim 14 (threaded manifold mounting) — Ram '488 mounts its plate/bars between carburetor and intake manifold; screw/threaded mounting of a nozzle into a manifold port is routine.
• Claims 16, 21 (two-piece plate with concentric grooves; central mounting bore 21) — Ram '488's base plate 41 mounted between the carburetor and intake manifold, with nitrous and fuel bars, is the closest art. The claimed groove/manifold construction is a conventional plenum design, and mounting an adapter plate on the carburetor's central air-cleaner stud is a conventional expedient. This is the claim family with the strongest non-obviousness argument (see § 7), because no retrieved reference expressly shows the two-groove concentric distribution architecture with the fuel line seated in a bottom-member port opening onto the nitrous groove.

7. Where the obviousness case is weak / the strongest rebuttals

A rigorous § 103 opinion must state the other side. '190 has several non-trivial defenses:

1. No single reference discloses nitrous oxide as the atomizing fluid in a coaxial nozzle. Kuechenmeister is an air-bled injector; the Ram references deliberately keep nitrous and fuel in separate bars. No retrieved reference discloses the claimed combination with nitrous as the oxidizer. The obviousness case therefore rests on substitution of nitrous for air — which requires the POSITA to recognize that a liquefied, flashing oxidizer behaves like (and better than) air for aspiration. That is arguably a step beyond mere substitution, though KSR would likely treat it as predictable given Ram '140's vaporization teaching.

2. "Air-bled" may not mean "high-pressure atomizing stream." An "air bleed" connotes a small auxiliary air flow (e.g., to prevent nozzle tip fouling), not the energetic 500–1000 psi stream the '190 claims. If Kuechenmeister's bled air is a minor flow, its disclosure does not fairly suggest the claimed pressure-differential aspiration of claim 9. ⚠️ I could not retrieve the Kuechenmeister text to resolve this — it is outcome-determinative and should be verified before relying on this reference.

3. Reference directionality not confirmed. Because I could not retrieve Kuechenmeister, Wallis, Nemnich, Charter, Benjamin, or the Audi reference in full, I cannot confirm which fluid occupies the inner vs. outer passage in Kuechenmeister. If fuel is in the annulus and air in the center tube, the reference would not disclose the claim-1 arrangement (oxidizer in the cavity; fuel in the internal line).

4. The examiner allowed the claims over all nine references (issued 1989-01-17). While not dispositive and issued pre-KSR, the allowance presumption means the examiner saw a patentable distinction — most plausibly the nitrous-oxide-specific atomization/aspiration combination and the two-piece grooved plate of claims 16–21. A challenger must overcome that record.

5. Potential secondary considerations. The patent was owned by Nitrous Oxide Systems, Inc., a leading nitrous-system vendor, and the page shows a long chain of security interests running to Holley Performance Products — indirect evidence that the technology was commercially significant. However, no evidence of record ties any commercial success to the '190 claims with the required nexus, and (as found in the earlier section) no litigation, IPR, or reexam exists to supply objective indicia. So secondary considerations are presently neutral/unproven, not favoring either side.

8. Conclusion

On the record available: Claims 1–15 and 17–21 are arguably obvious under § 103 over a primary combination of US 3,182,646 (Kuechenmeister, coaxial injector) in view of US 4,494,488 and/or US 4,572,140 (Ram Automotive — nitrous at ~900 psi, separate low-pressure fuel, tube-in-bore and annular-jacket geometry, vaporization cooling), and further in view of US 3,610,213 (Gianini — gas-jet aspiration/atomization) and US 4,211,200 (Audi NSU — vacuum amplification). The motivation is the field's own recognized problem (separate spray bars → fuel puddling, evidenced by Ram '488's bars 43/46), and the result — isolating the two fluids until a common discharge and letting the high-pressure stream aspirate and atomize the fuel — is predictable and squarely within KSR's "finite, predictable solutions" and "duplication of parts" categories. The pressure ranges and phase-change limitations are supplied by Ram, and the manifold-mounting/multi-port features are conventional.

However, this conclusion is conditional, and I want to be explicit about the condition rather than overstate it:

• The single most important unresolved fact is the internal geometry and fluid assignment of US 3,182,646, which I could not retrieve. If Kuechenmeister places fuel in the outer annulus or its "air bleed" is a nominal flow, the primary combination weakens considerably and the obviousness case would have to be rebuilt around Ram '488 + Gianini.
• Claim 16 (and its dependents 17–21, the grooved two-piece carburetor plate) is the most defensible claim, because no retrieved reference discloses the two-groove concentric distribution architecture with a fuel line seated in a bottom-member port communicating with the nitrous groove.
• I found no evidence of an actual prior § 103 adjudication of this patent (consistent with the earlier "no known litigation" finding), so the above is an independent re-analysis, not a report of any tribunal's decision.

Recommended verification before finalizing: pull the full texts of US 3,182,646, US 4,211,200, US 4,157,084, and US 2,482,864 (all available at patents.google.com/patent/USXXXXXXXA/en) to confirm fluid assignment and flow magnitudes, and confirm whether the examiner's reasons for allowance are recorded in the file wrapper. That will determine whether the primary combination above is a genuine § 103 case or merely a "could have been arranged" hypothesis.