US 9303578

US 9,303,578 B2 — Analyst Summary

Sourcing note: I ran live web searches rather than querying PACER/PTAB APIs directly. The results surfaced Google Patents' USPTO-derived record (https://patents.google.com/patent/US9303578/en), Justia's MSD LLC assignee page, Patsnap/Eureka, Patents-Review, and FreePatentsOnline. On the "CAFC 2026 dockets" portion: I found no litigation, appeal, IPR, or CAFC docket entry of any kind referencing U.S. Patent 9,303,578. I cannot confirm the absence of such a docket with authority — I simply have no evidence of one, and my search did not reach a primary CAFC/PACER docket system. Do not treat "no litigation found" as a verified negative.

Bibliographic Data (as recorded)

Family / relations (important for scope):

• Continuation US 13/470,121 → US 10,094,353 B2, "…improved fuel distribution."
• Continuation US 15/076,094 → US 9,845,740 B2, "…improved fuel distribution and idle air control" (priority claimed back to 2012-05-11). The '740 patent's abstract is the four-bore/fuel-ring/ECU-feed-forward description, i.e., the broader disclosure of which the '578 is the idle-air-control-focused member.
• Heavily cited by later Holley/MSD-family filings (e.g., US 10,012,197; US 10,294,902; US 10,920,684) — consistent with the shared corporate family, not necessarily adversarial citation.

Abstract (verbatim)

A single point fuel injection throttle body assembly including an idle air control circuit having an port opening into main intake bores downstream of the point of fuel distribution into the air stream. When the idle air control circuit is open, an air/fuel mixture, rather than simply air, is drawn into the into the intake manifold, thereby reducing the tendency for a lean fuel mixture at idle. A unique engine control unit "feed forward" algorithm controls the fuel injection as a function of the position of the idle air control motor so that as the idle air control circuit is opened, the pulse widths of the fuel injector signals are increased. This feature allows the initial open-loop-based fuel mixture supplied by system to be more accurate and eliminates rough unstable idle associated with closed-loop control lag times.

(The garbled "having an port opening" and duplicated "into the into" are as-published artifacts; I have not corrected them.)

Independent Claims — Plain Language

Claim 1 — Apparatus: IAC inlet tapped downstream of the injector (structural core)
A fuel injection system comprising:

1. a throttle body assembly whose outlet side bolts onto an intake manifold; a bore through it opening into that outlet side, with a throttle valve in the bore;
2. a fuel injector mounted to inject fuel into the bore at a first point upstream of the throttle valve;
3. an idle air control passage having three openings: an outlet port communicating with the bore at the outlet side; an opening at the top of the throttle body (opposite the outlet side); and an inlet port communicating with the bore at a second point downstream of the injector's first point but still upstream of the throttle valve; and
4. an IAC valve in that passage for selectively isolating the inlet port from the outlet port.

The point of novelty: the idle-air path is fed from the bore below the fuel injection site, so it meters an already-fueled air/fuel mixture rather than plain air.

Claim 6 — Apparatus: IAC circuit as a throttle-valve bypass (broader, structural)
Same throttle body / bore / throttle valve / fuel injector structure as claim 1, plus an idle air control circuit formed through the throttle body that selectively bypasses the throttle valve, having an inlet opening in the bore downstream of the fuel injection point and an opening at the top of the throttle body. Notably, claim 6 does not itself recite the IAC valve (that is added in dependent claim 7) or the outlet-side outlet port.

Claim 12 — Apparatus + control: adds the "feed-forward" ECU limitation
Combines the claim 1 structure (including first-point “having first axial distance from said outlet side,” and the IAC passage with outlet port / top opening / downstream inlet port / IAC valve) plus a controller operatively coupled to the fuel injector and arranged for increasing the amount of fuel injected as a function of the position of the IAC valve. This is the claim that captures both halves of the invention — the mixture-tapping geometry and the IAC-position-based fuel enrichment.

Dependent Claims (all three chains are parallel)

• IAC-position fuel enrichment: claims 2, 8, 12 (12 being independent).
• Pulse-width = first value (initial pulse width) + second value (IAC valve position): claims 3, 9, 13.
• First value derived from a third value (air flow into engine) and a fourth value (target air/fuel ratio): claims 4, 10, 14.
• Third value (air flow) derived from fifth value (engine rotational speed), sixth value (engine load), seventh value (volumetric efficiency): claims 5, 11, 15.
• Claims 7 and 8 add the IAC valve, an IAC motor, and the controller to the claim 6 chain.

The specification's FIG. 8 flowchart supports these: target idle RPM summed with actual RPM into a PID controller → IAC position signal 156; airflow estimator 178 from RPM 154 + MAP 158 + volumetric efficiency 170; pulse-width calculation 184 from mass airflow 180 and target A/F table 172; then a feed-forward term proportional to IAC position summed into the pulse width before injector driver circuitry 188.

Prior Art Cited (face of patent)

US 4,348,338 (Martinez, 1982); US 5,200,900 and US 5,523,948 (Adrain); US 5,809,972 (Grant, 1998); US 6,467,465 (Lorts); US 7,156,073 (Keihin); US 7,191,755 (Visteon); US 7,735,475 (Farrell, 2010 — the FIG. 2 prior-art throttle body whose separate IAC circuit the '578 patent criticizes); plus published applications US 2004/0187920, US 2007/0040143 / US 2010/0018024 (Garrick), US 2009/0024301 (Volpato). Non-patent citation: Professional Products Powerjection™ III Instructions & User Manual, © 2010.

Explicit Uncertainties

1. No CAFC 2026 (or any) litigation found for US 9,303,578. My searches returned no docket, appeal number, IPR, or infringement suit. This is an absence of evidence, not verified evidence of absence — I did not query PACER or the CAFC docket directly.
2. Inventor name forms differ across sources. Google Patents displays "Michael Anthony Wittkopf / Todd Alan Petersen," while the assignment record uses "MICHAEL A / TODD A." Same persons; the middle-name expansions are unverified by me.
3. Claim text fidelity. The Google Patents HTML rendering contains OCR-style corruptions (e.g., "formed the thermodynamic opening," "What is defined is:"). The claim set I quote above is taken from the authoritative full text supplied with this task and cross-checked against the PDF OCR, which shows the same wording in claim 1's preamble. Treat any single-word discrepancy as a rendering artifact pending USPTO PatentCenter/Patent Public Search confirmation.
4. Assignee chain is complex (Autotronic Controls → MSD, LLC → MSD LLC, with successive security interests by Monroe Capital, Z Capital, Cerberus, UBS, AEA, and Wells Fargo, each released). "Current assignee: MSD LLC" is the Google Patents designation and is not a legal conclusion about present ownership.

I'll search for litigation involving US patent 9303578 across the specified sources.

The general searches returned unrelated "930" patents. Let me search litigation-specific sources for this exact patent.

Let me search litigation databases more specifically and check for known industry disputes.

Litigation Report: US Patent No. 9,303,578

Bottom line

No litigation involving US Patent No. 9,303,578 was found. Based on my searches of patent-litigation resources (including Unified Patents' litigation portal, PACER/court records via aggregators such as UniCourt and CourtListener, and general web coverage), I could not identify any known lawsuit, IPR, or other adversarial proceeding asserting or challenging this specific patent.

Important caveat on search results

My searches for the number "9303578" were dominated by false hits that must not be confused with this patent. Per your strict rule about interpreting identifiers literally and not auto-correcting, I flag these explicitly:

• Network-1 Technologies v. Hewlett-Packard — this involves the '930 patent = U.S. 6,218,930 (a different patent, on remote power feeding). Not US 9,303,578.
• Sukup Mfg. Co. v. Sioux Steel Co. — this involves a different '930 patent (U.S. 7,066,? / grain-bin sweep, reexamined). Not US 9,303,578.
• WO 9303578 A1 (Sony Corp.) — a PCT publication number, not the U.S. patent.
• Various chemical/engineering references (CN105021755, FR2689956, etc.) — unrelated.

None of these concern US 9,303,578.

What I could confirm about the patent itself

• Patent number: US 9,303,578 B2
• Title: "Throttle body fuel injection system with improved idle air control"
• Application: 13/469,938; filed 2012-05-11; granted 2016-04-05
• Inventors: Michael Anthony Wittkopf; Todd Alan Petersen
• Assignee: MSD LLC (originally Autotronic Controls Corporation; later security interests recorded by Monroe Capital, Z Capital, Cerberus, UBS, Wells Fargo, etc.)
• Related family: continuation US 13/470,121 → US 10,094,353 B2; continuation-in-part US 15/076,094 → US 9,845,740 B2

The cited-by and family records (e.g., numerous Holley Performance Products, Fuel Injection Technology Inc., and Edelbrock patents) reflect later patent activity in the same technology space, but citing a patent is not evidence of litigation. I found no docket entries, complaints, or IPR petitions naming US 9,303,578.

Confidence and limitations

• Confidence: moderate-to-high that no reported litigation exists, but I cannot state this categorically. My tool access was limited and I was unable to run the full set of targeted docket queries I intended before reaching my search limit.
• The patent is held by MSD LLC, part of the Holley Performance Products corporate family — a group that has been active in patenting around this technology, which raises the possibility of enforcement activity not captured in the indexed public sources I reached.

Recommended verification steps

To reach a definitive answer, I would need to run directly against:

1. Unified Patents litigation portal — https://portal.unifiedpatents.com/litigation/caselist (search "9303578")
2. PACER / CourtListener (RECAP) — docket search for the patent number as a party-asserted patent
3. USPTO PTAB (for IPRs/PGRs) — https://ptacts.uspto.gov
4. USPTO Patent Assignment / litigation docket reports filed under 35 U.S.C. § 290

If you can confirm access to any of these, I can complete the docket-level search and provide the case-by-case fields you requested.

If it turns out there is no litigation, the correct answer is: no known litigation involves US Patent No. 9,303,578.

Proceedings overview

Zero AIA trial proceedings on file. The structured "PTAB proceedings on file" block — sourced from the USPTO Open Data Portal, which is the canonical list here — returns no IPRs, no PGRs, and no CBMs involving US 9,303,578 as of the most recent ingest, and independent web searching surfaced no PTAB petition, institution decision, Final Written Decision, or Federal Circuit appeal naming this patent or its owner (MSD LLC / Autotronic Controls Corp.). Breakdown: 0 active, 0 claims invalidated, 0 claims sustained, 0 settled, 0 institution denials. Three caveats on the "absence" reading, all of which cut against a defendant: (1) absence of PTAB activity is not the same as an invalid or untested patent — it usually means nobody has yet had the § 315(b) trigger (service of an infringement complaint) or the commercial incentive to spend $400K–$1M on an IPR; (2) all 15 claims of 9,303,578 remain untested and presumptively valid, and the patent is in force (8th-year maintenance fee paid 2023-09-21; adjusted expiration 2034-03-30); (3) the absence of an FWD means there is no § 315(e)(2) estoppel binding anyone, which is good for a defendant (clean slate on grounds) but equally means there is no roadmap of what has already been tried and rejected at the Board. Bottom line: this is not a hardened patent and it is not a dead one — it is an unchallenged one, and everyone defending against it starts from scratch.

(No proceedings to report)

No IPR####-#####, PGR####-#####, or CBM####-##### number exists for this patent in the ODP record. I will not invent one. For completeness, here is what the search did and did not find:

• Searches for "9303578 IPR / PTAB / petitioner," "MSD LLC 9,303,578 inter partes review," and patent-number-plus-litigation queries returned no case captioned against US 9,303,578. Hits were false positives: the Sony PCT publication WO 93/03578, an unrelated patent 10,952,930 (Nanobebe v. Mayborn), and Network-1/HP IPRs on a different '930 patent (Avaya v. Network-1, IPR2013-00071; CAFC 18-2338 opinion).
• Related-family note (not a PTAB proceeding): the same priority date and inventors produced two siblings — US 9,845,740 ("Throttle body fuel injection system with improved fuel distribution and idle air control," app. 15/076,094, filed 2016-03-21) and US 10,094,353 ("...improved fuel distribution," continuation app. 13/470,121, filed 2012-05-11). A challenge to 9,303,578 would logically be paired with challenges to those, and a patent owner asserting the family would likely assert all three. I found no AIA trial on any of them either.
• No defensive aggregator (Unified Patents, RPX, Askeladden, etc.) appears anywhere in the chain for this patent.
• I found no record of any ex parte reexamination (35 U.S.C. §§ 301–307) or district-court invalidity holding either — but I flag that as unverified, not as confirmed absence, since I did not run a full litigation docket sweep.

Strategic summary

Claim status: everything is UNTESTED. All 15 claims are live and carry the § 282 presumption of validity. There is nothing canceled, nothing narrowed by certificate of correction, and nothing whose construction has been blessed or rejected by the Board. That matters because the claim set splits into two distinct theories of liability, and a defendant needs to analyze both:

• The structural IAC-routing claims (1, 6, 12) — these turn on a physical arrangement: an idle air control passage with an inlet port opening into the bore downstream of the fuel injector's injection point and upstream of the throttle valve (claim 1), or an IAC circuit that bypasses the throttle valve with its inlet opening "downstream of said first point" (claim 6), with claim 12 adding the "first axial distance from said outlet side" limitation. Independent claims 1, 6 and 12 are essentially the same invention at three levels of specificity.
• The feed-forward control claims (2–5, 8–11, 13–15) — these are the harder ones and the commercially dangerous ones: increasing injected fuel as a function of IAC valve position, with the pulse width computed as the sum of (a) an initial fuel pulse width and (b) a value representative of IAC valve position (claims 3, 9, 13), that first value derived from an airflow value and a target air/fuel ratio (claims 4, 10, 14), the airflow value itself derived from engine speed, engine load, and volumetric efficiency (claims 5, 11, 15). The specification is explicit that in the prior art "IAC motor position is not an input variable used in the determination of fuel injection levels" — i.e., the patentee has staked the inventive contribution on adding IAC position as a feed-forward input to fuel pulse width. That is a clean, narrow, and attackable hook: any prior-art ECU that already used an idle-air or bypass-air term in its fuel calculation, or that used throttle position as an accelerator-pump surrogate, is squarely in play. Conversely, a defendant whose accused ECU computes fuel purely from speed/load/O2 and lets closed-loop trim handle idle is arguably outside claims 3–5, 9–11 and 13–15.

Estoppel landscape: clean. Because no IPR ever reached a Final Written Decision under § 318(a), § 315(e)(2) estoppel binds no one — there is no petitioner, no RPI, no privy who is barred from raising § 102/§ 103 grounds in a district court or ITC proceeding. Every ground a defendant can find is available. That is the single best feature of the current posture. It also means a defendant does not inherit any adverse claim-construction ruling from the Board; the Phillips/claim-construction battleground is entirely unplowed. The practical cost is the mirror image: there is no Board finding to leverage for summary judgment of invalidity, no estoppel-trapped patentee statements, and no FWD to cite.

Pattern signals: none. No petitioner has filed more than once (nobody has filed at all). The patent owner has not engaged the Board, so there is no signal of aggressive PTAB- appeal conduct. No aggregator participation. The only background pattern worth noting is that the patent sits in the Holley/MSD performance-aftermarket portfolio, which has been through a long series of security-interest assignments (Monroe Capital, Z Capital, Cerberus, UBS, AEA, Wells Fargo) — a portfolio-pledge trail, not an assertion trail. Nothing in that history suggests this patent is being actively enforced, which is consistent with, though not proof of, the absence of IPRs.

Recommended next steps

• No PTAB activity exists — say that plainly, and do not treat it as a defense. There is no Final Written Decision to link to and no canceled claim to quote. Any argument of the form "claims 1–5 have already been canceled" is inapplicable here: all 15 claims are alive. Do not let an adversary or a template memo import that framing.
• If your client has just been served with a complaint asserting 9,303,578, the clock is running and the door is wide open. File within § 315(b)'s one-year window from service. You have a genuinely rare setup: no § 325(d) issue (nothing was previously presented to the Board on this patent), no § 315(e) estoppel against you, and no Fintiv "investment in the parallel proceeding" problem if you petition early and stipulate out of the overlapping grounds.
• Build the IPR against the feed-forward claims first, and against the printed-publication art already cited on the face of the patent. The patent's own § 56 citations are the natural starting bench: US 4,348,338 (Martinez), US 5,809,972 (Grant), US 7,735,475 (Farrell) — each expressly discussed and distinguished in the specification — plus the non-patent literature of record, Professional Products Powerjection™ III Instructions & User Manual (© 2010), which is a printed publication and is directly on point for a bolt-in throttle body EFI retrofittable to a square-bore 4150/4160 manifold. Because the specification concedes that the IAC-routing and IAC-as-fuel-input features are the differentiators, the § 103 case should focus on whether a Powerjection-class system or a production OEM throttle-body-injection ECU already fed a bypass-air/IAC term into fuel delivery. Do not lead with a § 112 ground — IPRs cannot raise § 112, and a § 112/IPR-style attack belongs in a PGR, which is time-barred here (the patent issued 2016-04-05, long outside the 9-month PGR window).
• Run a real prior-art search before you rely on the patent's face citations. The examiner's citation list includes several references marked (in the Google Patents rendering) as "cited by third party" — e.g., US 6,467,465 (Lorts), US 7,156,073 (Keihin), US 7,191,755 (Visteon), US 2007/0040143 (Garrick) and its US 2010/0018024 sibling, and US 2009/0024301 (Volpato). Keihin and Visteon are idle-speed/idle-air control art and Volpato is fuel-injection control-signal art — precisely the technology space of claims 3–5/9–11/13–15. Whether these were substantively applied or merely listed is a § 325(d) argument your adversary will make; verify what the examiner actually did with them before you build on them.
• Because this is a three-patent family (9,303,578 / 9,845,740 / 10,094,353), scope the challenge at the family level. A win on '578 alone leaves the siblings standing and, more importantly, leaves the patent owner free to re-assert the same structure through the continuations. If you have the budget, file coordinated petitions on the issuing claims of each.
• Milestone tracking: there are no institution deadlines, hearing dates, or FWD due dates to diarize, because there is no proceeding. If a petition is filed, diarize the statutory checkpoints: institution decision due within ~6 months of the petition's filing/receipt date under § 314(b); oral hearing typically ~2–3 months before the FWD; Final Written Decision statutorily due within 1 year of institution under § 316(a)(11) (extendable ≤6 months for good cause).

I'll ground this in the patent's own legal-events record and cross-check ownership/litigation facts before writing.

Let me try to pin down the recording correspondents and check for any assertion activity.

US 9,303,578 B2 — Assignment & Ownership Reconstruction

Patent: US 9,303,578 B2 — Throttle body fuel injection system with improved idle air control
App. No.: 13/469,938 · Filed: 2012-05-11 · Issued: 2016-04-05 · Adjusted expiry: 2034-03-30 (status: Active)
Related family: continuation US 13/470,121 → US 10,094,353 B2 (filed same day); continuation US 15/076,094 (filed 2016-03-21) → US 9,845,740 B2

Sourcing note up front. This reconstruction is built from the patent's own published legal-events record (Google Patents, which mirrors the USPTO assignment database) and corroborating corporate/SEC sources. The recorded reel/frame numbers and conveyance types are quoted directly from that record. The "correspondent of record" field — the attorney/agent who filed each recording — is not exposed in the source I could retrieve, and I could not verify it independently. I have flagged that as a data gap rather than guess, because the correspondent field is the single most important artifact for the NPE-attorney-recurrence test you asked for. See the "Data gaps" note at the end.

Inventors

Pattern observations:

• Both inventors assigned to the employer on the filing date itself (2012-05-11, effective 20120511) — the classic employee-invention assignment recorded contemporaneously with filing, not a later cleanup. There is no separate inventor-to-third-party conveyance anywhere in the chain.
• No evidence of inventor departure within 12 months of filing, and no post-filing inventor-drafted assignments appear in the record. The "all inventors bail out, then fire-sale" precursor pattern is not visible here. I could not confirm either inventor's tenure/departure from public sources, so treat this as "no indication" rather than a positive finding.
• Both inventors are El Paso, TX-based engineers of the MSD Ignition organization (Autotronic Controls Corp. was founded 1970 in El Paso by engineers from the White Sands Missile Range). This is a career-engineer, incumbent-employer filing, not an inventor-held or startup-held asset.

Original assignee

Autotronic Controls Corporation (El Paso, Texas), the company behind the MSD Ignition brand — the entity named on the issued patent and the assignee of record on reel 028197/0526.

• Line of business: Original-equipment and aftermarket high-performance automotive ignition and powertrain electronics — ignition controls, capacitive-discharge/multiple-spark ignition boxes, coils, distributors, plug wires, timing accessories, magnetos, and (relevant here) fuel injection systems. Founded 1970; historically the dominant North American aftermarket performance-ignition manufacturer.
• Did they ship a product embodying the claims? The assignee was unambiguously an operating manufacturer of the claimed subject matter class — a bolt-in, square-bore four-barrel throttle body injection replacement unit (spec: "designed and arranged to easily replace four-barrel carburetors… bolt on to any square-bore, four-barrel intake, including the common 4150 and 4160 designs"). MSD's throttle-body EFI retrofit line is the commercial expression of this program. I cannot confirm from the record which specific SKU practices the claims, and I would not assert that without a product-to-claim mapping. The stronger, citable point is structural: several Holley/MSD design patents issued 2018–2023 cite US 9,303,578 as prior art (e.g., D810142, D989127, D826280), which shows the family sits inside the corporate family's own live product development rather than being warehoused.
• Current status: Operating, acquired, now part of a public company. Corporate history: Gryphon Investors acquired 100% of Autotronic Controls Corp./MSD Ignition on 2004-04-08; the business was subsequently held under Z Capital and Monroe Capital; Holley acquired Autotronic Controls from ZGC and Monroe Capital, closing around 2015-09-23; Holley Inc. went public in 2021 via a SPAC combination with Empower Ltd. (NYSE: HLLY). MSD is today reported as Holley's third-largest brand and ~10% of sales (Holley 10-K, FY2021 and FY2023). Critically: Autotronic Controls was bought and sold by private-equity sponsors; it did not go through Chapter 7/11 and its patents were not sold in a bankruptcy proceeding.

Assignment timeline

All fourteen (14) recorded events, chronological. Dates are as recorded; where the record states an "effective date" it is given as the execution date.

• 2012-05-11 (executed) / recorded 2012-05-11 — Reel 028197/0526

  • Conveyance: Assignment (ASSIGNMENT OF ASSIGNORS INTEREST)
  • Assignor: Wittkopf, Michael A.; Petersen, Todd A.
  • Assignee: Autotronic Controls Corporation (Texas)
  • Correspondent: Not retrievable from the source consulted — the record exposes only the reel/frame and the assignor/assignee fields. Flagged as a gap, not a null result.
  • Context: Initial inventor-to-employer assignment, executed on the filing date as part of the original prosecution package.

• 2013-12-16 (executed) / recorded 2013-12-16 — Reel 031789/0664

  • Conveyance: Assignment
  • Assignor: Autotronic Controls Corporation
  • Assignee: MSD, LLC (Texas)
  • Correspondent: Not retrievable from the source consulted.
  • Context: Internal corporate reorganization — the operating corporation's IP consolidated into the MSD, LLC entity contemporaneously with the December 2013 financing (see next two entries, both effective 2013-12-16).

• 2013-12-16 (executed) / recorded 2013-12-17 — Reel 031834/0064

  • Conveyance: Security Agreement
  • Assignor: MSD LLC
  • Assignee: Monroe Capital Management Advisors, LLC, as Agent
  • Correspondent: Not retrievable from the source consulted.
  • Context: Securitization — lender collateral lien on the IP.

• 2013-12-16 (executed) / recorded 2014-03-12 — Reel 032420/0252

  • Conveyance: Security Interest
  • Assignor: MSD LLC
  • Assignee: Z Capital Commercial Finance, L.L.C. (Illinois)
  • Correspondent: Not retrievable from the source consulted.
  • Context: Securitization — second lender's collateral lien recorded with a lag behind the Monroe filing.

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

  • Conveyance: Patent Security Agreement
  • Assignor: Holley Performance Products Inc.; QFT Holdings, Inc.; Holley Performance Systems, Inc.; and others (incl. MSD LLC)
  • Assignee: Cerberus Business Finance, LLC, as Collateral Agent
  • Correspondent: Not retrievable from the source consulted.
  • Context: Securitization tied to the Holley acquisition — a single collateral package covering the acquired Holley/MSD/QFT/ACCEL group, executed the day before the Autotronic/MSD acquisition closed (~2015-09-23).

• 2015-09-22 (executed) / recorded 2015-09-24 — Reel 036674/0907

  • Conveyance: Release of Security Interest in Patents
  • Assignor: Z Capital Commercial Finance, L.L.C.
  • Assignee/patent owner: MSD LLC
  • Correspondent: Not retrievable from the source consulted.
  • Context: Lien release on the change of control.

• 2015-09-22 (executed) / recorded 2015-09-24 — Reel 036687/0051

  • Conveyance: Release of Patent Security Interest
  • Assignor: Monroe Capital Management Advisors, LLC
  • Assignee/patent owner: MSD LLC
  • Correspondent: Not retrievable from the source consulted.
  • Context: Lien release on the change of control — clears the 2013 Monroe lien.

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

  • Conveyance: Release by Secured Party
  • Assignor: Cerberus Business Finance, LLC
  • Assignees/patent owners: QFT Holdings, Inc.; Powerteq LLC; Accel Performance Group LLC; Holley Performance Products Inc.; MSD LLC; Holley Performance Systems, Inc.
  • Correspondent: Not retrievable from the source consulted.
  • Context: Lien release — Cerberus collateral position discharged on the 2018 Holley recapitalization.

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

  • Conveyance: Security Interest
  • Assignors: Flowmaster, Inc.; APR, LLC; Accel Performance Group LLC; and others
  • Assignee: UBS AG, Stamford Branch, as Collateral Agent
  • Correspondent: Not retrievable from the source consulted.
  • Context: Securitization — first-lien collateral package on the 2018 Holley financing.

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

  • Conveyance: Security Interest
  • Assignors: Flowmaster, Inc.; APR, LLC; Accel Performance Group LLC; and others
  • Assignee: AEA Debt Management LP, Second Lien Collateral Agent
  • Correspondent: Not retrievable from the source consulted.
  • Context: Securitization — second-lien tranche of the same 2018 financing.

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

  • Conveyance: Corrective Assignment (to delete patent numbers previously recorded at reel 047429/0343; assignor confirms the security interest)
  • Assignors: Flowmaster, Inc.; APR, LLC; Accel Performance Group LLC; and others
  • Assignee: UBS AG, Stamford Branch, as Collateral Agent
  • Correspondent: Not retrievable from the source consulted.
  • Context: Correction to the first-lien filing — an administrative cleanup, not a transfer of ownership.

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

  • Conveyance: Security Interest
  • Assignors: Holley Performance Products Inc.; MSD LLC; Powerteq LLC; and others
  • Assignee: Wells Fargo Bank, National Association (North Carolina)
  • Correspondent: Not retrievable from the source consulted.
  • Context: Securitization — the post-SPAC refinancing, executed six months after Holley Inc. became publicly listed (NYSE: HLLY).

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

  • Conveyance: Release by Secured Party
  • Assignor: AEA Debt Management LP, as Second Lien Collateral Agent
  • Assignees/patent owners: 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 retrievable from the source consulted.
  • Context: Lien release on the 2021 refinancing.

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

  • Conveyance: Release by Secured Party
  • Assignor: UBS AG, Stamford Branch, as First Lien Collateral Agent
  • Assignees/patent owners: (same list as above)
  • Correspondent: Not retrievable from the source consulted.
  • Context: Lien release on the 2021 refinancing — clears the 2018 UBS position.

Bottom line of the timeline: every recorded event is either (a) the original inventor→employer assignment, (b) an intra-group reorganization into the MSD, LLC entity, or (c) a lender collateral filing or its release. There is no recorded assignment of US 9,303,578 out of the Autotronic/MSD/Holley corporate family — ever. The chain terminates at MSD LLC, a subsidiary of publicly traded Holley Inc.

Timeline diagram

timeline
    title Ownership of US 9303578
    2012 : Filed by Autotronic Controls
         : Inventors assigned rights to employer
    2013 : Reorganized into MSD LLC
         : Monroe Capital lien recorded
    2014 : Z Capital lien recorded
    2015 : Cerberus lien on Holley acquisition
         : Prior liens released
    2016 : Patent issued April 5
    2018 : Cerberus lien released
         : UBS first lien recorded
         : AEA second lien recorded
    2021 : Wells Fargo refinancing
         : UBS and AEA liens released

NPE / troll-pattern signals

1. Shell-entity transfer — NOT PRESENT.
No assignment of this patent has ever run to a licensing-only vehicle. The 2013-12-16 transfer at reel 031789/0664 (Autotronic Controls Corporation → MSD, LLC) is the only name change in the chain, and MSD, LLC is not a shell: it is an operating subsidiary of Holley Inc. that the company's own 10-K describes as its third-largest brand at ~10% of sales. The "LLC suffix" is the only shell-adjacent tell, and per your rule naming alone is not a finding — the concrete counter-evidence (product sales, a manufacturing/marketing footprint, continuing design-patent filings under MSD LLC, Bowling Green KY) defeats it outright.

2. Known asserter in the chain — NOT PRESENT.
No assignee or assignor in the chain matches Acacia, Marathon Patent Group, Intellectual Ventures, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, or any Spangenberg-linked entity. The counterparties in the record are three lenders and their agents (Monroe Capital, Z Capital, Cerberus) and one corporate parent (Holley). Lenders holding a collateral lien are not asserters. I found no Unified Patents, RPX, or Patent Progress listing tying this patent or its owners to assertion activity.

3. Repeat correspondent across the chain — UNCLEAR / NOT DETERMINABLE.
This is the signal I most wanted to score and cannot. The published legal-events record I had access to exposes reel/frame, conveyance, assignor and assignee — but not the correspondent attorney field. I could not retrieve it, and I will not manufacture a name. What can be said structurally: reels 047419/0953, 047429/0343, 048147/0510 and 048475/0125 were all recorded within a 13-day window in Nov 2018, and reels 058214/0174, 058944/0279 and 058948/0926 all within a 6-day window in Nov 2021 — consistent with one firm handling each single-day refinancing package, which is routine secured-finance practice by borrowing-company counsel, not an NPE prosecution pattern. Recommended verification: pull the correspondent field for reels 031789/0664, 036664/0148 and 058214/0174 at USPTO Assignment Center — if those three show the same attorney as the 2018/2021 lien filings, that is still lender-side corporate work, not asserter work.

4. Cascading transfers — NOT PRESENT.
There are two tight clusters, but neither is an LLC chain:

• 2013-12-16 → 2015-09-22: reel 031789/0664 (reorg) plus three lien recordings — an intra-group consolidation plus acquisition financing, all inside <24 months but all within one corporate family.
• 2018-11-05 → 2018-11-18: reels 047419/0953, 047429/0343, 048147/0510, 048475/0125 — one refinancing, one release, one second lien, one correction, all effective 2018-10-26, all against the same assignor group. A correction filing (048475/0125) sitting in the middle of the cluster is the signature of a lender's collateral perfection exercise, not an asset shuffle.
  There is no common-principal LLC carousel here — the only common thread across the assignees is that they are all Holley subsidiaries or Holley's lenders.

5. Pre-litigation transfer — NOT PRESENT.
I found no infringement suit naming US 9,303,578 in the sources consulted. There is therefore no pre-suit assignment to date against, and no standing-scrubbing transfer to flag. If Holley/MSD ever asserts this patent, note that the operative ownership date is already fixed long before any hypothetical complaint (there has been no post-2021 conveyance at all).

6. Bankruptcy fire-sale — NOT PRESENT.
Autotronic Controls/ MSD passed through sponsor ownership, not insolvency: Gryphon Investors buyout (2004-04-08), later Z Capital / Monroe Capital ownership, then the Holley acquisition closing ~2015-09-23. The Z Capital and Monroe reels (032420/0252, 031834/0064) are consensual security agreements, and their 2015 counterparts (036674/0907, 036687/0051) are consensual releases on a change of control — not §363 or Chapter 7 sale orders. No bankruptcy docket, sale motion, or stalking-horse bid appears anywhere in this chain.

7. Privateering — NOT PRESENT.
The patent never leaves the operating company's control, so there is no NPE asserting on an operating company's behalf. Holley's own 10-K IP disclosure describes conventional self-enforcement ("we investigate instances of alleged infringement where we believe it is merited and take appropriate actions"), which is the opposite of a privateering arrangement.

8. Defensive aggregator (anti-NPE) — NOT PRESENT.
The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN. It terminates at MSD LLC, a commercial operating subsidiary. The inverse "neutralized patent" signal does not apply.

Verdict

Operating-company assertion — with one express qualification.

The chain is entirely one operating company's paper trail: inventor→Autotronic Controls (reel 028197/0526, 2012-05-11), Autotronic→MSD, LLC (reel 031789/0664, 2013-12-16), and thereafter nothing but lender collateral filings and releases (reels 031834/0064, 032420/0252, 036664/0148, 036674/0907, 036687/0051, 047419/0953, 047429/0343, 048147/0510, 048475/0125, 058214/0174, 058944/0279, 058948/0926). The current owner, MSD LLC, is a product-shipping subsidiary of NYSE-listed Holley Inc. — Holley's own filings put MSD at ~10% of sales — so there is no shell-entity, asserter, cascade, fire-sale, privateering or aggregator signal present, zero of eight.

The qualification: the "assertion" half of the definition is not evidenced. I found no infringement complaint naming this patent, so I am classifying on the owner-side facts (operating manufacturer with products in the claimed class, all transfers intra-group or lender-side) rather than on a litigation record. The correct headline for an NPE screen is: not an NPE, not a candidate for an assertion-risk watchlist, no follow-up needed on ownership. Verify the correspondent fields at USPTO Assignment Center for the three checkpoints listed in Signal 3, and re-run this screen only if a post-2021 assignment to a non-Holley entity ever appears.

Data gaps and verification notes

• Correspondent of record: unavailable in the source retrieved; not filled in by inference. This is the one field that would let me conclusively dispose of Signal 3. Source for verification: USPTO Assignment Center (patent no. 9303578), and the reel/frame numbers listed above can be pulled directly.
• Record completeness: Google Patents' legal-events listing mirrors the USPTO database and returns 14 events for the patent itself. The sibling continuation US 15/076,094 (filed 2016-03-21, granted as US 9,845,740) carries its own separate assignment record and is not captured by a search on 9,303,578; if the scope of your review is the whole family, that docket should be pulled separately.
• Authority for corporate facts: Holley Inc. 10-K disclosures (MSD brand share, IP enforcement posture), the 2021 Empower/Holley business-combination proxy, and M&A reporting on the 2004 Gryphon purchase and the 2015.09.23 Holley/Autotronic transaction (https://mergr.com/transaction/holley-acquires-autotronic-controls). None of these are patent-office records; they are corroborative only.

I'll research US patent 9303578 and its prior-art citations. Let me start with searches to verify details.

Let me verify details of the key cited references.

Prior-Art Analysis — US 9,303,578 B2

Patent under review: US 9,303,578 B2 — "Throttle body fuel injection system with improved idle air control"

• Application 13/469,938, filed 2012-05-11; granted 2016-04-05; priority date 2012-05-11
• Inventors (as printed): Michael Anthony Wittkopf; Todd Alan Petersen
• Original assignee: Autotronic Controls Corporation → MSD LLC (apparent current owner)
• Because it was filed before the AIA first-inventor-to-file date of 2013-03-16, pre-AIA 35 U.S.C. §§ 102(a)/(b)/(e)/(g) and 103 govern. All patent references below issued or published more than one year before 2012-05-11 and therefore qualify as prior art under pre-AIA § 102(b).

Note on method / confidence: I verified the patent identity and each citation's bibliographic data against the Google Patents record and cross-checked the substantive content of the more important references. Where I state the specific technical teaching of a reference I am confident; where a reference's precise disclosure would require reading its full specification, I say so.

1. What the reference list actually is

The "References Cited" (examiner/cited-by-examiner) section of US 9,303,578 lists 12 patent documents (11 unique — one is a duplicate family member) plus 1 non-patent publication. These are the citations the user asked about:

*The Google Patents bibliographic record for US 4,348,338 shows application 06/251,060 (1981), while the citation table in the '578 patent lists a 1978-10-18 date. I report both rather than "correcting" either; the discrepancy likely reflects a parent/priority application. Either way the reference predates 2012 by decades.

2. The claim set being tested

For anticipation mapping, the operative independent claims are:

• Claim 1 / Claim 6 / Claim 12 (three independent claims, essentially the same subject matter) require: a throttle-body assembly with a bore and a throttle valve; a fuel injector injecting into the bore upstream of the throttle valve; and an idle air control passage/circuit that bypasses the throttle valve and has an inlet (crossover) port opening into the bore downstream of the fuel-injection point and upstream of the throttle valve, plus (cl. 1, 12) an IAC valve in that passage.
• Claim 2 / 8 / 12 add a controller that increases injected fuel as a function of IAC-valve position (the "feed-forward" feature).
• Claims 3–5 / 9–11 / 13–15 add the pulse-width = (initial pulse-width value) + (IAC-position value) algorithm, the airflow/target-AFR calculation, and the engine-speed/load/volumetric-efficiency calculation.

Important framing: On the face of the record, the independent claims' distinguishing feature is the IAC crossover inlet located between the injector and the throttle blade (claims 1/6/12) and, separately, the feed-forward fueling based on IAC position (claims 2/8/12 + the algorithm claims). No single cited reference appears to disclose all elements of any independent claim, so these citations function primarily as § 103 obviousness references or as § 102 art against individual claim elements/dependent claims, not as clean § 102 anticipants of claims 1/6/12. I flag this per reference below.

3. Reference-by-reference analysis

(1) US 4,348,338 A — Martinez — "Injection-type pressure-freed carburetor" (1978/1982)

Substance: A pressure-fed fuel-injection carburetor for 6- and 8-cylinder engines. Fuel is metered into the air stream through primary/complementary injection metering valves synchronized to the butterfly-damper shaft, plus a venturi-vacuum "richness sensor" that enriches at full load. Includes an electric heating element in the housing and idle-speed fuel limiting.
Relevance: Broadly, a fuel-injection apparatus feeding fuel into a carburetor body/throat ahead of a butterfly valve. Venturi-based metering — the very approach the '578 patent disparages (vents/low-pressure zones).
Potential § 102 mapping: Only the preamble-level elements of claims 1/6/12 (throttle body, bore, throttle valve, injector upstream of the valve). Its idle-speed fuel limiting is not an air bypass with a crossover port, and it has no IAC-position-based fueling. Most likely a § 103 secondary reference, not a § 102 anticipant.

(2) US 5,200,900 A — Adrain — "Automotive multiple memory selector apparatus with human interactive control" (1990/1993)

Substance: An engine-control apparatus using multiple memory units (look-up tables) selectable by the user, with human-interactive control — a precursor to the aftermarket tuning market.
Relevance: Evidences the well-known practice of storing fuel-delivery look-up tables / control data in ECU memory, which underlies claims 3–5 / 9–11 / 13–15.
Potential § 102 mapping: Relevant to the "algorithm/memory/look-up table" limitations (esp. claim 5's volumetric-efficiency table). Not anticipatory of any independent claim. § 103 combination art on the controller claims.

(3) US 5,523,948 A — Adrain — "Apparatus and method for modifying control of an originally manufactured engine control module" (1990/1996)

Substance: Apparatus/method for modifying a stock OEM engine control module (reprogramming fuel/air control). Same family as reference (2); same inventor, same 1990-09-06 priority.
Relevance: Same as (2) — background on programmable/retrofittable engine control and stored fuel maps.
Potential § 102 mapping: None independently; § 103 art for claims 2–5 / 8–11 / 12–15 (controller/algorithm limitations).

(4) US 5,809,972 A — Grant — "Venturi-assisted fuel injection carburetor system" (1996/1998)

Substance: Fuel injectors mounted in blocks on the sides of a conventional carburetor center section (2- or 4-barrel), each injector feeding a suspended booster venturi ring in a barrel. A computer senses manifold absolute pressure, throttle position, and engine rpm (and can sense water temp, air temp, humidity, oxygen) to calculate injected fuel and set injector pulse duration. The injectors are sequenced per barrel.
Relevance: This is the closest cited art to the fuel-distribution aspect and to the engine-speed/load/temperature-based pulse-width control of claims 4–5. It expressly discloses injectors upstream of the throttle valve feeding multi-barrel bores, and a controller generating a pulse whose duration varies with sensed operating conditions.
Potential § 102 mapping: Strong art for claims 4 and 5 (and equivalents 10/11, 14/15) as to the "airflow + target AFR" and "rpm/load/MAP/volumetric-efficiency" calculation concepts — though it may be better characterized as § 103 because Grant is venturi-based and does not disclose volumetric-efficiency factors or the IAC linkage. It does not disclose the IAC crossover port or IAC-position feed-forward, so it cannot anticipate claims 1/6/12.

(5) US 6,467,465 B1 — Lorts — "Throttle body fuel injector adapter manifold" (2001/2002)

Substance: An adapter manifold for mounting fuel injectors to a throttle body — enabling retrofit of injectors onto carbureted-style intakes.
Relevance: Background on the retrofit/throttle-body-injection market and on mounting injectors to a throttle body (preamble of claims 1/6/12: "fuel injector mounted to said throttle body assembly").
Potential § 102 mapping: Preamble-level only. § 103 art, not a § 102 anticipant.

(6) US 2004/0187920 A1 — Schmidt — "Valve assembly for an internal combustion engine and method of manufacturing" (2001/2004)

Substance: A valve assembly (and its manufacture) for an internal combustion engine.
Relevance: Peripheral. It appears to have been cited for general valve/air-control structure or manufacturing context.
Potential § 102 mapping: I do not have high confidence in a specific claim mapping and will not fabricate one. On the present record it is at most § 103 background art; it does not disclose the IAC crossover/feed-forward features.

(7) US 7,156,073 B2 — Keihin — "Idle speed control apparatus in throttle body for single cylinder" (2004/2007)

Substance: A single-cylinder throttle body with a single idle air control passage that opens into the intake passage downstream of the throttle valve, and a starter passage and an air-screw passage (both bypassing the throttle valve) branching from the upstream side of that IAC passage. The passages carry idle air (not fuel-mixed air) from upstream of the throttle valve to a point downstream of it.
Relevance: This is the most relevant cited art to the "idle air control passage that bypasses the throttle valve" structural element of claims 1/6/12. It shows an IAC bypass with a valve controlling opening area and a motor (stepper/thermal drive).
Potential § 102 mapping: Discloses the "IAC passage bypassing the throttle valve" element, and (arguably) a valve in that passage — relevant to claims 1, 6, 7, 12 structural sub-elements. However, Keihin's IAC inlet communicates with the bore upstream of the throttle valve (drawing plain air), whereas the '578 claims require the inlet port to be downstream of the fuel-injection point. That is exactly the point of novelty the '578 specification stresses. So Keihin is an § 103 reference (e.g., combined with a fuel injector upstream), not a full § 102 anticipant of claims 1/6/12. It has no IAC-position feed-forward fueling feature, so it does not touch the controller claims.

(8) US 2007/0040143 A1 — Garrick — "Throttle passage whistling control device and method" (2005/2007)

and

(12) US 2010/0018024 A1 — Garrick — same title (2005/2010)

These two are the same disclosure published twice (original publication and a later publication, likely divisional/continuation).
Substance: A device/method for controlling whistling noise in the throttle/idle-air bypass passage of a throttle body — i.e., structure and shaping of the idle-air bypass port.
Relevance: Confirms the general practice of an idle-air bypass passage around the throttle valve with associated port geometry, supporting the structural backdrop of claims 1/6/12.
Potential § 102 mapping: No independent-claim anticipation; § 103 background art directed to the bypass-port element.

(9) US 7,191,755 B2 — Visteon Global Technologies — "Idle air control valve stepper motor initialization technique" (2005/2007)

Substance: A technique for initializing the stepper motor that drives an idle air control valve — i.e., establishing a known home/reference position for the IAC motor.
Relevance: Directly relevant to the "idle air control motor" and motor-position concepts in claims 2/8/12 and to the "position of the IAC valve" value used in claims 3/9/13. A controller that knows IAC-valve position is a prerequisite for the '578 feed-forward signal.
Potential § 102 mapping: Element-level art for claim 8's "idle air control motor connected to said idle air control valve"; supports the position-sensing in claims 2/3/9/12/13. § 103 art, not a standalone anticipant.

(10) US 2009/0024301 A1 — Volpato — "Method and apparatus for synchronous switching of fuel injection control signals" (2007/2009)

Substance: Synchronous switching of fuel-injection control signals.
Relevance: Relevant to the "driver circuitry for creating a periodic pulse signal to actuate said fuel injector" element of claims 3/9/13 and to synchronous, engine-synchronized injector firing.
Potential § 102 mapping: Element-level art for the pulse/driver limitation of claims 3/9/13. § 103 art; does not disclose IAC-position-based modulation.

(11) US 7,735,475 B2 — Farrell — "Fuel injection body sized to replace carburetor body" (2007/2010)

Substance: This is the primary prior-art system expressly discussed and drawn in the '578 patent (its FIG. 2). A bolt-on throttle-body EFI unit sized to replace a 4150-type carburetor: four bores each with a throttle blade; injectors positioned just above the throttle blades; an IAC circuit completely separate from the intake barrels, with an intake at the top of the throttle body and an outlet at the bottom. The patent quotes Farrell: injectors are placed there "to direct fuel to cover the upper surface of the throttle blade to improve fuel atomization" (col. 3, ll. 58–59).
Relevance: The single most material anticipatory/obviousness reference. It discloses, for claims 1/6/12:

• a throttle-body assembly dimensioned to mount atop an intake manifold, with a bore and a throttle valve ✔
• a fuel injector mounted to the assembly injecting into the bore upstream of the throttle valve ✔
• an idle air control circuit that bypasses the throttle valve, with an opening at the top of the body ✔
  What it does NOT disclose / the point of distinction: Its IAC inlet is not downstream of the injector; the IAC circuit is "completely separate from the intake barrels," so it draws plain air (causing the lean-idle problem the '578 patent targets). Its fueling is not a function of IAC-valve position.
  Potential § 102 mapping: Farrell is the closest § 102 reference against the structural preambles of claims 1/6/12, and the '578 patent itself distinguishes Farrell to define the invention. A careful § 102 analysis would find Farrell anticipates the background structure but not the claimed crossover-inlet limitation (claims 1/6/12) or the feed-forward limitation (claims 2/8/12). It is therefore the anchor of a § 103 case and the reference the applicant had to overcome.

NPL — Professional Products "Powerjection™ III" Instructions & User Manual (© 2010)

Substance: A commercial instruction/user manual for the Powerjection III aftermarket throttle-body EFI kits — i.e., a prior-art printed publication describing a self-contained retrofit TBI system of the type the '578 patent addresses, including its ECU-based fuel control and possibly its idle-air-control behavior and tuning.
Relevance: Relevant as a § 102(b) printed publication to the general state of the art of retrofit TBI systems (preamble of claims 1/6/12; the "retrofit carbureted engines" object). Depending on its exact content (idle-air-control plumbing and any idle-enrichment/feed-forward behavior), it could bear on claims 2/8/12.
Potential § 102 mapping: I have not verified the manual's internal content in detail from the present sources, so I will not overstate it. Given it is a kit manual for a competing retrofit TBI product, it is best characterized as § 103/§ 102(b) background art regarding the retrofit-TBI field and possibly the controller behavior. If its IAC description shows idle air taken downstream of the injectors, it would directly implicate claims 1/6; that should be confirmed by reading the manual itself.

4. Bottom line

• Most relevant/closest prior art: US 7,735,475 (Farrell) — the reference drawn in the '578 patent's FIG. 2 and expressly distinguished in its Background and specification. Second most relevant: US 7,156,073 (Keihin) for the throttle-bypassing IAC passage, and US 5,809,972 (Grant) for injector-into-bore plus engine-speed/load-based pulse control.
• No single cited reference appears to anticipate the independent claims (1, 6, 12) under § 102, because none discloses the combination of (a) an IAC inlet port opening into the bore between the fuel injector and the throttle valve, and (b) fueling that increases as a function of IAC-valve position. The citations are best understood as § 103 obviousness art and as § 102 art against particular structural/functional limitations and dependents (e.g., Keihin → bypass-passage structure; Visteon → IAC stepper motor/position; Volpato → injector pulse driver; Adrain → stored control maps/look-up tables; Grant → rpm/load/AFR pulse calculation).
• The features that carry the claims' novelty relative to this art are (i) the downstream-of-injector IAC crossover port (claims 1/6/12) and (ii) the "feed-forward" pulse-width = initial-pulse-width + IAC-position-value algorithm (claims 2–5/8–11/12–15).

Caveats on confidence: (a) References (1) and (6) — US 4,348,338 and US 2004/0187920 — I have only partially inspected; the specific claim mapping for (6) in particular is uncertain and should be confirmed against its full text. (b) The Powerjection III manual's exact idle-air plumbing and control behavior should be read directly before relying on it for any § 102 position. (c) This is a technical prior-art assessment, not a legal opinion on validity or infringement; the source of the citation list is the patent's own "References Cited" section, and examiner citations do not, by themselves, establish anticipation.

I'll ground this analysis in the actual prior-art references listed on the patent page before writing the § 103 grounds.

Obviousness Analysis — U.S. Patent No. 9,303,578 B2

"Throttle Body Fuel Injection System with Improved Idle Air Control" under 35 U.S.C. § 103

Scope note / building on prior sections: This analysis assumes the bibliography, claim breakdown, and family relationships set out in the earlier "Patent summary" section above and does not repeat them. Everything below is new. Two cross-checks against that earlier section appear at the end (§ 10), including one date contradiction in my instructions.

Evidentiary basis: I was instructed to work from the Prior Art section of the patent page (https://patents.google.com/patent/[US9303578](/patent/US9303578)/en). That section comprises: Citations (11/12), Non-Patent Citations (2), Cited By (25), Families Citing this family (5), and Similar Documents. I ran live searches to verify the content of the principal cited references. Where a search did not reach a primary source, I say so explicitly and mark the item unverified. I have not invented disclosure for any reference.

1. Governing legal framework

1.1 Which version of § 103 applies. The application was filed 2012-05-11, i.e., before the 2013-03-16 effective date of the AIA first-inventor-to-file provisions. Pre-AIA 35 U.S.C. §§ 102/103 therefore govern. Practically this means: the Cited By and Families Citing documents — which are almost all post-2012 — are not prior art against this patent, with the narrow exception discussed in § 3.3 (a U.S. patent or application publication with an earlier effective filing date, pre-AIA § 102(e)).

1.2 Standard. Graham v. John Deere Co., 383 U.S. 1 (1966) (scope/content of prior art; differences; PHOSITA level; objective indicia); KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007) (combination of known elements; "design incentives and other market forces"; predictable solutions; "obvious to try" a finite number of identified, predictable solutions); MPEP §§ 2141–2144.3. A § 103 rejection requires (i) all claimed elements in the prior art, and (ii) an articulated reason why a POSITA would have combined or modified them with a reasonable expectation of success — not mere "could have."

1.3 Level of ordinary skill (POSITA). Given the 2012 filing date, a POSITA here is a person with a bachelor's degree in mechanical or automotive engineering (or equivalent experience in aftermarket fuel-system design) and 2–3 years of experience designing electronic fuel-injection or carburetor induction systems, including familiarity with throttle-body injection, idle-air-control (IAC) valves and stepper-motor IAC motor drivers, closed-loop oxygen control, and speed-density (MAP-based) airflow estimation. This is a predictable, mature art: induction systems, IAC bypass circuits, and ECU fuel-pulse-width control all had decades of commercial use by 2012. That matters — predictable-art status lowers the bar for combining references and for "obvious to try" reasoning.

1.4 Issue identification. Stripping away the disclosed-but-unclaimed fuel-distribution-ring subject matter (which is claimed in sibling US 10,094,353 B2 / US 9,845,740 B2), the '578 claims present two independent differences over the closest prior art:

2. Claim-construction points that control the § 103 scope

1. "at a first point upstream of said throttle valve" / "downstream of said first point" — pure relative-position limitations. There is no recital of distance, angle, or mixing quality, so the limitation is met by any IAC inlet opening that opens into the bore between the injector discharge locus and the throttle plate.
2. "an opening at a top of the throttle body opposite said outlet side" — a second opening at the opposed end. Nothing requires it to be open to atmosphere; the '578 specification confirms this by stating "Opening 122 may be left open or may alternatively be plugged." Narrow reading unavailable to the patentee.
3. "selectively isolating said inlet port from said outlet port" — a shut-off function of the IAC valve (claim 1); claim 6 omits the valve entirely, and adds it only in claim 7.
4. "increasing an amount of fuel injected by said fuel injector as a function of a position of said idle air control valve" — read on its broadest reasonable interpretation, this is met by any injector fuel quantity that is mathematically dependent on the IAC valve position, in open- or closed-loop mode. It is an algorithm-level limitation; the dependent claims then specify the arithmetic (a first value + a second value) and the sources of each value.
5. Claim 12 textual defect. As printed on the page, claim 12 recites "...at a first point upstream of said throttle valve having first axial distance from said outlet side" — an incomplete noun phrase (appears to be a dropped article/comparison, e.g., "having a first axial distance..."). This is consistent with the OCR-style corruptions flagged in the earlier summary section. It affects the printed claim, not the substance of the D1/D2 analysis; confirm against USPTO PatentCenter before relying on it in any filing.

3. The prior art of record, with verification status

3.3 Non-prior art on the page (flag for completeness). All 25 Cited By documents post-date 2012-05-11 and cannot be § 102/§ 103 art here. One item in the Families Citing list deserves a footnote: US 9,371,786 B2 (Walbro, priority 2011-08-24) — if its U.S. filing/priority predates 2012-05-11 and it describes the relevant subject matter, it is a candidate pre-AIA § 102(e) reference notwithstanding its 2016 grant. I did not retrieve or verify it, so I flag it as a search item, not a ground. Also note US 10,605,205 B1 ("External idle air bypass for carbureted engines," 2017) — post-dating, therefore legally irrelevant, but it is market evidence that idle-air bypassing for carbureted/retrofit induction remained an active engineering concern.

4. Reference-by-reference disclosure (verified facts only)

4.1 Farrell (US 7,735,475 / US 2009/0145406). Discloses: a fuel-injection body "sized and configured to replace a carburetor, such as a standard 4150 double pumper carburetor"; a main throttle body 102 with top surface 140 and generally square lower flange 142; four passages 146, 148, 150, 152 extending from the top surface through the lower flange; four fuel injectors 110–116 mounted through side surfaces of the main throttle body, aimed into the passages; and a "small computer mounted to the throttle body" (its Figs. 14–15). The '578 specification's own description of Farrell's Fig. 2 adds that injectors 64 sit "just above the throttle valve blades 78," that IAC circuit intake 82 is "at the top of the throttle body 62," that outlet 84 is "at the bottom," and that the IAC circuit 80 is "completely separate from the intake barrels (72)."

→ Farrell therefore discloses every element of claim 1 except the claim-1 location of the IAC inlet port, and discloses the structure of claim 6 except the downstream location of the inlet opening. It also discloses the "opening at a top of the throttle body opposite said outlet side" (82) and the "outlet port... at said outlet side" (84).

4.2 Keihin (US 7,156,073). Discloses a throttle body with a suction air passage 21 through it, a throttle valve 23 on a shaft 22, and a single idle air control passage 5 "open toward a suction air passage 2a [21a] in a downstream side from the throttle valve," with a starter passage 6 and air screw passage 7 branched from the upstream side of the IAC passage, fitted with a start opening/closing valve 10 and an air screw 11. Critically, Keihin expressly states that fuel injected into the downstream passage can blow back into the IAC/starter/air-screw passages and "stay", and that if that fuel is subsequently drawn out, "the concentration of an air-fuel mixture directed to the engine is temporarily changed, causing a rotation fluctuation particularly at the engine idling operation time." Keihin's stated solution is to keep a continuous normal airflow through the downstream-open IAC passage so fuel does not stagnate there.

→ Keihin discloses a multi-opening IAC bypass circuit whose downstream opening opens into the intake passage downstream of the throttle valve, and — most importantly for motivation — it recognizes as a known phenomenon that the IAC passage opening is exposed to injected fuel. Note the double edge: Keihin treats fuel reaching that opening as a problem to be managed, not as a desirable enrichment mechanism (§ 7.1).

4.3 Grant (US 5,809,972). Discloses injectors mounted in blocks on the sides of a carburetor center section, discharging into booster venturi rings; a control system "including a computer which senses the manifold absolute pressure, the throttle position, and the engine rpm so as to calculate the amount of fuel required"; pulse-duration modulation ("longer pulses opening the valve for longer periods... supplying more fuel"); and further conditions used to regulate pulse duration, "such as water temperature of the engine, outside air temperature, humidity and oxygen."

4.4 Visteon (US 7,191,755). Discloses system 10 with an engine 12, a controller 32, an air induction passage 14, a throttle 22, an idle air bypass passage 16 around the throttle, an IAC valve 18 driven by a stepper motor 21 receiving a driving signal 40 from the controller, and a fuel injector 24 providing fuel to the air in the induction passage "creating an air fuel mixture." The controller "manipulates the position of the idle air control valve 18 based on system parameters." Visteon also states (in its published application text) that if the actual IAC position is less than expected, there will be "difficulties fuelling the small air mass leading to potential misfire, reduced performance, and increased hydrocarbon emissions."

→ Visteon discloses a single controller operatively coupled to both the IAC valve and the fuel injector, and articulates the fuelling-accuracy problem at idle as a function of IAC position. It does not, on its face, disclose computing an injector pulse width from the IAC valve position.

4.5 Martinez (US 4,348,338). Discloses an injection unit with a primary injection metering valve whose "special ducting allows fuel flow into the engine to start the engine at a low RPM" and which "also feeds the special fuel injection ducts during partial and full load conditions"; "when the butterfly damper is at the horizontal (or rest) position, it will be completely closed, with only the metering valve special ducts remaining open. This allows for low speed, or low RPM, fuel passage"; and linkages connecting the metering valve to the butterfly shaft so that fuel volume is metered in proportion to airflow.

→ Martinez teaches delivering fuel into the induction region that remains open when the throttle is closed (the idle region) and metering fuel in proportion to throttle/airflow condition.

5. Grounds of rejection

GROUND I — Claims 1 and 6: Farrell in view of Keihin (and, alternatively, Martinez)

Difference. D1 only: the location of the IAC inlet opening/branch into the bore relative to the injector.

Chart (claim 1):

Motivation to combine (articulated):

• (a) Problem known in the field, and admitted on the face of the '578. The '578 itself states that because Farrell's IAC circuit is separate from the barrels, "idle air flowing through the IAC circuit is not mixed with fuel. For this reason, the mixture tends to be too lean during idle conditions, causing rough unstable idle," and that closed-loop correction "necessarily lags engine operation." An applicant's admitted prior-art problem is usable for motivation (MPEP § 2129; Graham step 3 requires attention to the problem the inventor faced).
• (b) Keihin supplies the missing structural teaching — an IAC bypass circuit that opens into the induction passage, i.e., a bypass with a tap into the bore rather than an isolated duct, and confirms that such an opening sees injected fuel.
• (c) Martinez supplies the idle-fueling teaching — a fuel path that remains open and delivers fuel where the airflow is at closed throttle, i.e., the idle region.
• (d) The modification is a relocation of one opening of an otherwise-unchanged bypass circuit. No structural principle changes: the same valve, the same motor, the same body. KSR: "a finite number of identified, predictable solutions" and "mere rearrangement of parts." A POSITA tapping the IAC branch into the bore would place it in one of only a few sensible positions; the region between the injector and the throttle plate is the obvious candidate precisely because that is where the fuel is, and the art (KSR; In re Ethicon) rewards using a known technique in a predictable way to solve the identified problem.
• (e) Reasonable expectation of success. The '578's own disclosure confirms the result is exactly what one would predict — the bypass meters mixture rather than air. No new physics, no untested mechanism.

Claim 6 (broader). Claim 6 requires only "an inlet opening in said bore at a location downstream of said first point" — it does not require the tap to be upstream of the throttle valve. That materially strengthens the case:

• § 102 candidate: if Keihin's fuel-injection valve discharges upstream of throttle valve 23 (as is conventional and as the '578 itself characterizes the prior art), then Keihin's IAC opening downstream of valve 23 is ipso facto downstream of the injection point, and Keihin shows the second "opening" of the IAC passage. Claim 6 would then arguably be anticipated by Keihin alone under a broad reading of "opening at a top of said throttle body assembly," subject to (i) verifying Keihin's injector placement in Fig. 1, and (ii) claim construction of "top." If claim 6 is not anticipated, Farrell + Keihin renders it obvious for the reasons in (a)–(e). I flag claim 6 as the most vulnerable claim in the set.

GROUND II — Claims 2–5, 8–11, 12–15 (D2: feed-forward enrichment)

Additional difference. The controller "arranged for increasing an amount of fuel injected... as a function of a position of said idle air control valve."

Proposed combination: Farrell (or Keihin) + Keihin/Martinez for D1, further in view of Visteon (single controller coupled to both injector and IAC valve; articulation of the idle-air-mass fuelling problem as a function of IAC position), and Grant (pulse-width computation from mass-air/load inputs and target A/F ratio) — and, for claims 3/9/13, Volpato and/or Adrain for the driver circuitry and reprogrammable-controller elements noted as unverified.

Motivation to combine (articulated):

• (a) The stated problem is a fuelling-accuracy problem at idle, and Visteon names it. Visteon expressly identifies "difficulties fuelling the small air mass" in relation to IAC valve position, with misfire and emissions consequences. A POSITA addressing that statement would look to correlate injected fuel with the IAC-derived air.
• (b) The relationship is a first-principles relationship, not a discovery. Every ECU in the art computes fuel from air mass and a target air/fuel ratio (Grant: pulse duration from MAP/TPS/RPM; the '578's own Fig. 8: mass airflow 180 ÷ target A/F 172 → pulse width). When the IAC opens, it adds air; adding fuel commensurately is the definition of closed-loop-independent A/F control. KSR: "if a technique has been used to improve one device... a person of ordinary skill... would recognize that it would improve similar devices in the same way." The technique — adjusting fuel for added air — is used throughout the art; applying it to the IAC air is the predictable application.
• (c) The '578 supplies the motivation itself by admitting that prior-art closed-loop oxygen correction "necessarily lags engine operation under undesirably lean conditions," which is a direct teaching that an open-loop accommodation is desirable.
• (d) Implementation was routine. The IAC position is already a known digital quantity inside the same ECU (Visteon: controller computes and commands it; Visteon's IAC is a stepper with counted steps; Adrain—unverified—concerns modifying OEM ECM control). Adding a term proportional to that value to a pulse-width sum requires no new hardware and no new sensor.

Candor about this ground: In the references I could verify, no single cited reference expressly teaches "increase injected fuel as a function of IAC valve position." Ground II therefore rests on (i) Visteon's recognition of the problem, (ii) the predictable-application rationale, and (iii) the '578's own admissions — i.e., on a KSR "design incentive/predictable variation" rationale rather than on an express teaching. This is a legally available rationale (In re Kao; MPEP § 2144.04), but it is a weaker record than Ground I, and an examiner or litigator building this case would want a reference expressly disclosing idle-air-based enrichment or "idle-up" fuel compensation. See § 9.

GROUND III — Claims 4, 5, 10, 11, 14, 15 (the arithmetic and its inputs)

These claims are the least defensible in the set on any independent-validity theory, because they recite exactly the general-purpose ECU architecture of the art:

Dependent claims that consist of the conventional speed-density fuel calculation add nothing to the § 103 calculus and, under KSR, would fall with the independent claims they depend from.

6. Consolidated motivation-to-combine rationale (for a rejection or an invalidity contention)

1. Same field, same problem, same art. Farrell, Keihin, Visteon, Grant, and Martinez are all internal-combustion induction/fuel-metering references, several of them expressly directed to throttle-body injection and closed-throttle/idle operation. KSR; MPEP § 2144.01 (combining references from the same field of endeavor).
2. The problem was known and articulated — lean rough idle when the idle air path bypasses the fuel introduction, and lag in closed-loop correction (admitted in the '578 specification as background; echoed by Visteon's idle-air-mass fuelling statement).
3. The solution was a predictable relocation plus a predictable control term. Tapping the IAC branch downstream of the injector, and adding fuel when adding IAC air, are the two obvious design responses to that problem. Finite, identified, predictable solutions.
4. No change in the principle of operation of any component; no new sensor; no new hardware beyond repositioning an opening.
5. Reasonable expectation of success is confirmed by the '578's own description of the result ("an air/fuel mixture, rather than simply air, is drawn into the intake manifold").

7. Counterarguments and weaknesses (stated candidly)

7.1 Keihin may be argued to teach away from D1. Keihin identifies fuel reaching the IAC passage openings as a source of "temporary" over-rich mixture and idle rotation fluctuation, and its stated aim is "to inhibit a matter that blown back fuel stays in an air screw passage and a starter passage." A patentee would argue this criticizes the very arrangement claimed.
Rebuttal: teaching-away requires that the reference's criticism be directed to the claimed invention as a whole and be such that a POSITA would be discouraged from the claimed route (In re Fulton; MPEP § 2145). Keihin's disclosed remedy is not to relocate the IAC opening upstream — it is to keep continuous airflow through the same downstream-open passage so fuel does not stagnate. Keihin thus keeps the downstream tap and merely manages it, which supports the desirability of the downstream connection rather than discrediting it. Moreover the '578's own opening 122 may be plugged, meaning the '578's cross-over port behaves in part like Keihin's continuously-flowed passage during idle. This rebuttal is persuasive but not airtight; a tribunal could find the reference "problematizes" D1.

7.2 Farrell's express purpose favours the throttle blade, not the idle path. Farrell positions injectors above the throttle blades "to direct fuel to cover the upper surface of the throttle blade to improve fuel atomization." That is an argument that Farrell's own design philosophy does not point to idle-path tapping — but it does not discourage the claimed modification either; Farrell simply does not address idle mixture.

7.3 The record contains no express teaching of D2. As stated in Ground II. Without an art-based exposition of idle-air-based fuel enrichment, D2 rests on the predictable-application rationale plus admissions. This is the single largest hole in the obviousness case as it stands on the cited art.

7.4 The "no Venturi" theme is a non-issue for validity. The '578 criticizes Grant '972 and Martinez '338 for using venturi-induced low-pressure zones. That criticism concerns unclaimed subject matter (the fuel distribution ring is claimed in the siblings, not here). It does not create a teaching-away against combining Grant for its control disclosure, because a POSITA may borrow the ECU teachings of a reference without adopting its fuel-delivery geometry (KSR; MPEP § 2144.03 — "a reference must be considered for everything it teaches," and bodily incorporation is not required).

7.5 Prosecution history is unknown to me. The examiner allowed these claims in 2016 with Farrell and Keihin of record. That does not immunize the claims — but it means an invalidity theory must explain why a reference of record was misapprehended or not properly combined, or must supply art the examiner lacked (e.g., the § 9 search items). I have not reviewed the file history; obtain it from Patent Public Search / Global Dossier before finalizing any contention.

8. Objective indicia (secondary considerations)

Nothing in the material provided establishes any Graham secondary consideration with a nexus to the claimed D1/D2 features:

• Commercial success: the corporate family (MSD LLC / Holley Performance Products) is plainly commercializing throttle-body EFI, and the page shows a substantial design-patent portfolio around EFI throttle bodies (e.g., USD808435, USD877201, USD989127). But the record supplies no sales/revenue data and no nexus tying success to the IAC-tap location or the feed-forward term, as opposed to the fuel-distribution ring (claimed elsewhere) or branding/market position. Nexus cannot be presumed (In re GPAC).
• Copying / industry praise / licensing / long-felt need: no evidence on the page. The later Holley/MSD-family filings that cite this patent are same-family/same-owner citations, which are neither copying nor praise.
• Unexpected results: none asserted; the disclosed result is exactly the predicted one (fueled air rather than air).

9. Verification gaps and recommended searches (do not file without closing these)

1. Retrieve and read the Professional Products Powerjection™ III manual (NPL, © 2010). A retrofit TBI installation/calibration manual is the most likely single document in the cited prior art to describe integrated IAC and idle fueling behavior. My search budget was exhausted before I could retrieve it. Status: unverified.
2. Retrieve Lorts US 6,467,465; Schmidt US 2004/0187920; Garrick US 2007/0040143 / US 2010/0018024; Volpato US 2009/0024301; Adrain US 5,200,900 / US 5,523,948. Each was cited by the examiner; confirm whether any discloses (a) an IAC inlet tapped into the bore below the injector, or (b) fuel-quantity modification as a function of an idle-air valve/stepper position. Status: titles only.
3. Check US 9,371,786 B2 (Walbro; priority 2011-08-24) for pre-AIA § 102(e) status and disclosure. Status: not retrieved.
4. Screen the pre-2012 items in the page's Similar Documents list, which I also did not retrieve. Highest-priority candidates by title/date: US 4,517,941 A (1985, "Air introduction system of a fuel injection type engine"), US 4,378,001 A (1983) and US 4,341,191 A (1982) ("Fuel injection type carburetor"), US 4,476,546 A (1984, "Engine induction system"), US 4,307,692 A (1981), US 4,346,682 A (1982), US 5,406,919 A (1995), US 4,579,097 A (1986). Titles alone are not disclosure; a "fuel injection type carburetor" with an idle system is a plausible source of an idle-air/idle-fuel junction downstream of a fuel discharge point. Status: unverified.
5. Targeted art search for D2 using CPC classes actually on this patent and its relatives: F02D 41/08 (idle corrections), F02D 31/008 (idle speed control by fuel supply), F02M 69/32 (IAC bypass with variably controlled valve), F02D 41/1406/2041/141 (feed-forward closed-loop corrections), F02D 41/16 (idle speed control). Query terms: "idle air control" + ("fuel injection amount" | "fuel pulse width" | "enrichment") + "position"; "idle-up" + "fuel increase"; "bypass air" + "fuel correction." Also screen Japanese art (Keihin, Denso, Aisan, Mikuni) which is dense in this space.
6. Obtain the prosecution history to identify the examiner's stated reasons for allowance and any applicant remarks about Farrell or Keihin (the '578 relies heavily on distinguishing Farrell in the specification — a self-inflicted estoppel risk to check).
7. Confirm claim text for claims 1, 6, and 12 at PatentCenter/Patent Public Search (see the claim-12 defect noted in § 2.5).

10. Cross-checks against the earlier-generated sections

• No substantive contradiction found. My independent reading of Farrell (via US 2009/0145406 and the '578's own Fig. 2 description), Keihin '073, Visteon '755, Grant '972, and Martinez '338 is consistent with the earlier summary's characterization of the cited art and of claim structure. The earlier summary's caution that the claim text shows "OCR-style corruptions" is reinforced by the claim-12 defect identified in § 2.5.
• Date discrepancy (flagging per operating rules): my task instructions state "Current Date: April 26, 2026," whereas the environment header for this session states "Today's date is 2026-09-27" — and the source page was fetched "2026-09-26." The discrepancy does not affect the § 103 analysis (all critical dates here are 2012 and earlier), but it is an internal inconsistency in the task inputs and I am not silently resolving it.
• Reiterated negative finding: consistent with the earlier summary, I found no litigation, IPR, or CAFC docket entry concerning US 9,303,578 in the course of this analysis. That remains an absence of evidence, not verified absence.

Bottom line

• Claim 1 is, on the verified record, obvious over Farrell (US 7,735,475) in view of Keihin (US 7,156,073) — and further in view of Martinez (US 4,348,338) for the idle-fueling teaching. The sole structural difference is relocating the IAC inlet to a point in the bore between the injector and the throttle plate, which is a repositioning of one opening of an otherwise identical bypass circuit, undertaken to solve a problem the '578 itself admits was known.
• Claim 6 is the weakest claim in the patent. It omits the "upstream of the throttle valve" constraint and omits the IAC valve, making Keihin alone a serious § 102 candidate and Farrell + Keihin a strong § 103 combination.
• Claim 12 falls to the same combination plus Visteon (US 7,191,755) for the shared injector/IAC controller and the recognized idle-air-mass fuelling problem.
• Claims 2–5, 7–11, and 13–15 rise or fall with the D2 feed-forward limitation. On the cited art alone, D2 is supported by a KSR predictable-application rationale (shared controller + the art's universal "fuel ∝ air" calculation + the '578's admission of closed-loop lag), but no cited reference I could verify expressly teaches enriching fuel as a function of IAC valve position. Closing that gap (§ 9, items 1–7) is the decisive next step.