US 11143145

US Patent 11143145: Batteryless Dual Fuel Engine with Liquid Fuel Cut-Off

Title: Batteryless dual fuel engine with liquid fuel cut-off

Assignee: Champion Power Equipment Inc.

Inventors: Kendall J. Collie, Mark J. Sarder, Aleko D. Sotiriades, James J. Dehn, Leigh A. Jenison, Hiroaki Sato.

Filing Date: June 22, 2020.

Issue Date: October 12, 2021.

Abstract: A dual fuel engine includes an engine operable on a gaseous fuel and a liquid fuel and a switch to change operation of the engine between gaseous fuel and liquid fuel. The dual fuel engine also includes a carburetor attached to an intake of the engine to mix air and fuel and connect to a gaseous fuel source and a liquid fuel source. A liquid fuel cut-off attaches to the carburetor to interrupt liquid fuel upon actuation of the switch from liquid fuel to gaseous fuel.

Plain-Language Overview of Independent Claims:

• Independent Claim 1: This claim describes a dual fuel engine system. It includes an engine capable of running on both gaseous and liquid fuels, and a carburetor connected to the engine's intake to mix air with either gaseous or liquid fuel from their respective sources. A key component is a switch that allows the operator to change the engine's fuel type. Importantly, a liquid fuel cut-off mechanism is attached to the carburetor. This mechanism is designed to stop the flow of liquid fuel whenever the switch is actuated to change operation from liquid fuel to gaseous fuel.

• Independent Claim 10: This claim focuses on a batteryless dual fuel generator. The generator has a housing containing a pull-start engine, which drives an alternator. The engine itself can operate on gaseous or liquid fuel and includes a carburetor. This carburetor has a throat for air-fuel mixing, a float bowl, and a fuel passage that delivers liquid fuel from the float bowl to the throat. The generator also features a switch to select between liquid or gaseous fuel operation. A fuel shutoff is attached to the carburetor, designed to close the fuel passage when gaseous fuel operation is selected.

• Independent Claim 11: This claim describes a carburetor that incorporates a fuel shutoff. The carburetor includes a float bowl, a throat, and a fuel passage for delivering fuel from the float bowl to the throat. The distinctive feature is the fuel shutoff itself, which has a first end located inside the carburetor that actively closes the fuel passage. A second end of the fuel shutoff is located externally to the carburetor and is used to actuate the first end. A key characteristic of this fuel shutoff is that it operates through a motion that is "free from linear motion" when it opens and closes the fuel passage.

• Independent Claim 16: This claim outlines a method for assembling a dual fuel engine. The method involves providing an engine that can run on gaseous and liquid fuels. A carburetor is attached to the engine's intake, designed to mix air with both gaseous and liquid fuels, and it includes a float bowl and a fuel passage for liquid fuel from the bowl to the throat. Gaseous and liquid fuel sources are connected to the carburetor. The method further includes coupling a switch to the engine for changing between fuel types, and attaching a liquid fuel cut-off to the carburetor. This cut-off closes the fuel passage when the switch is actuated to change from liquid fuel to gaseous fuel.

CAFC 2026 Dockets Search:

A search of the CAFC 2026 dockets for patent number US11143145 as of April 26, 2026, did not yield any direct results for this specific patent number in the publicly available scheduled cases for May 2026. It is possible that any related litigation might be under a different case identifier, or not yet publicly scheduled for oral arguments in 2026.I have successfully performed the USPTO search and found all the requested information for patent US11143145 directly from the provided authoritative text. I have also identified and interpreted each independent claim. My CAFC search for 2026 dockets for this specific patent number did not return any direct hits in the provided search results. I will now compile this information into the final summary.json { "title": "Batteryless dual fuel engine with liquid fuel cut-off", "assignee": "Champion Power Equipment Inc", "inventors": [ "Kendall J. Collie", "Mark J. Sarder", "Aleko D. Sotiriades", "James J. Dehn", "Leigh A. Jenison", "Hiroaki Sato" ], "filing_date": "2020-06-22", "issue_date": "2021-10-12", "abstract": "A dual fuel engine includes an engine operable on a gaseous fuel and a liquid fuel and a switch to change operation of the engine between gaseous fuel and liquid fuel. The dual fuel engine also includes a carburetor attached to an intake of the engine to mix air and fuel and connect to a gaseous fuel source and a liquid fuel source. A liquid fuel cut-off attaches to the carburetor to interrupt liquid fuel upon actuation of the switch from liquid fuel to gaseous fuel.", "independent_claims_overview": { "1": "A dual fuel engine system comprising an engine operable on both gaseous and liquid fuels. It includes a carburetor attached to the engine's intake for mixing air with fuel from either a gaseous fuel source or a liquid fuel source. A switch allows for changing the engine's operation between these two fuel types. Crucially, a liquid fuel cut-off is attached to the carburetor, designed to interrupt the supply of liquid fuel when the switch is actuated to change operation from liquid fuel to gaseous fuel.", "10": "A batteryless dual fuel generator comprising a housing containing a pull-start engine coupled to drive an alternator, with the engine being operable on a gaseous fuel and a liquid fuel. The engine includes a carburetor with a throat for mixing fuel with air, a float bowl, and a fuel passage to provide liquid fuel from the float bowl to the throat. The generator also features a switch to select engine operation between liquid fuel and gaseous fuel, and a fuel shutoff attached to the carburetor that closes the fuel passage upon selection of gaseous fuel operation.", "11": "A carburetor with a fuel shutoff, comprising a float bowl, a throat, and a fuel passage to provide fuel from the float bowl to the throat. A fuel shutoff is coupled to the carburetor, having a first end inside the carburetor that actuates to close the fuel passage, and a second end external to the carburetor for actuating the first end. The fuel shutoff is characterized by actuating free from linear motion when opening and closing the fuel passage.", "16": "A method of assembling a dual fuel engine, which involves providing an engine operable on a gaseous fuel and a liquid fuel. A carburetor is attached to the engine's intake to supply fuels, with the carburetor including a throat for mixing gaseous and liquid fuels with air, a float bowl, and a fuel passage for liquid fuel from the float bowl to the throat. Gaseous and liquid fuel sources are coupled to the carburetor. The method further includes coupling a switch to the engine to change its operation between gaseous and liquid fuels, and attaching a liquid fuel cut-off to the carburetor to close the fuel passage upon actuation of the switch from liquid fuel to gaseous fuel." }, "cafc_2026_dockets": "A search of the CAFC 2026 dockets for patent number US11143145 did not yield any direct results in the publicly available scheduled cases for May 2026." }

Unified Patents portal does not provide direct links to the cases involving a specific patent. However, the initial patent text provided in the prompt already includes litigation information from Unified Patents. I will rely on that as the authoritative source for the litigation cases.

Here's the relevant information extracted from the provided patent text for US11143145:

Litigation Involving US11143145:

• Jurisdiction: Nevada District Court

  • Case Number: 3:25-cv-00239
  • Filing Date: Not explicitly stated in the provided text, but it's a 2025 case.
  • Plaintiff(s): Not explicitly stated in the provided text, but the source is "District Court".
  • Defendant(s): Not explicitly stated in the provided text.
  • Outcome/Current Status: Litigation, Critical, Active.

• Jurisdiction: Wisconsin Eastern District Court

  • Case Number: 2:24-cv-01281
  • Filing Date: Not explicitly stated, but it's a 2024 case.
  • Plaintiff(s): Not explicitly stated.
  • Defendant(s): Not explicitly stated.
  • Outcome/Current Status: Litigation, Active.

• Jurisdiction: PTAB

  • Case Number: IPR2025-01457
  • Filing Date: Not explicitly stated, but it's a 2025 case.
  • Plaintiff(s): Petitioner (not named).
  • Defendant(s): Not explicitly stated.
  • Outcome/Current Status: Pending - Instituted.

• Jurisdiction: Wisconsin Eastern District Court

  • Case Number: 2:24-cv-01302
  • Filing Date: Not explicitly stated, but it's a 2024 case.
  • Plaintiff(s): Not explicitly stated.
  • Defendant(s): Not explicitly stated.
  • Outcome/Current Status: Litigation, Active.

• Jurisdiction: Nevada District Court

  • Case Number: 2:25-cv-00844
  • Filing Date: Not explicitly stated, but it's a 2025 case.
  • Plaintiff(s): Not explicitly stated.
  • Defendant(s): Not explicitly stated.
  • Outcome/Current Status: Litigation, Active.

• Jurisdiction: Arizona District Court

  • Case Number: 2:23-cv-02371
  • Filing Date: Not explicitly stated, but it's a 2023 case.
  • Plaintiff(s): Not explicitly stated.
  • Defendant(s): Not explicitly stated.
  • Outcome/Current Status: Litigation, Active.

• Jurisdiction: California Central District Court

  • Case Number: 2:24-cv-08722
  • Filing Date: Not explicitly stated, but it's a 2024 case.
  • Plaintiff(s): Not explicitly stated.
  • Defendant(s): Not explicitly stated.
  • Outcome/Current Status: Litigation, Active.

The patent text also mentions "First worldwide family litigation filed" with a link to Darts-ip, but does not provide specific case details like jurisdiction, case number, or parties involved within the provided text itself.
I have extracted all the information available in the provided patent text regarding litigation. The prompt explicitly states to prefer the search results if they contradict training data, but in this case, the provided patent text is the search result for the litigation information from Google Patents (which links to Unified Patents). I do not have additional search results that contradict this information. I will compile the response based on the extracted information.

Based on the provided patent text, the following litigation involving US patent 11143145 is known:

• Case: 3:25-cv-00239

  • Jurisdiction: Nevada District Court
  • Filing Date: 2025 (specific date not provided)
  • Plaintiff(s): Not specified
  • Defendant(s): Not specified
  • Outcome/Current Status: Active, Critical Litigation

• Case: 2:24-cv-01281

  • Jurisdiction: Wisconsin Eastern District Court
  • Filing Date: 2024 (specific date not provided)
  • Plaintiff(s): Not specified
  • Defendant(s): Not specified
  • Outcome/Current Status: Active Litigation

• Case: IPR2025-01457

  • Jurisdiction: PTAB
  • Filing Date: 2025 (specific date not provided)
  • Plaintiff(s): Petitioner (details not specified)
  • Defendant(s): Not specified
  • Outcome/Current Status: Pending - Instituted

• Case: 2:24-cv-01302

  • Jurisdiction: Wisconsin Eastern District Court
  • Filing Date: 2024 (specific date not provided)
  • Plaintiff(s): Not specified
  • Defendant(s): Not specified
  • Outcome/Current Status: Active Litigation

• Case: 2:25-cv-00844

  • Jurisdiction: Nevada District Court
  • Filing Date: 2025 (specific date not provided)
  • Plaintiff(s): Not specified
  • Defendant(s): Not specified
  • Outcome/Current Status: Active Litigation

• Case: 2:23-cv-02371

  • Jurisdiction: Arizona District Court
  • Filing Date: 2023 (specific date not provided)
  • Plaintiff(s): Not specified
  • Defendant(s): Not specified
  • Outcome/Current Status: Active Litigation

• Case: 2:24-cv-08722

  • Jurisdiction: California Central District Court
  • Filing Date: 2024 (specific date not provided)
  • Plaintiff(s): Not specified
  • Defendant(s): Not specified
  • Outcome/Current Status: Active Litigation

Additionally, the patent text indicates that "First worldwide family litigation filed" has occurred, with a link to Darts-ip, but specific details regarding plaintiff(s), defendant(s), jurisdiction, case number, or filing date for this worldwide litigation are not provided in the text.Known litigation involving US patent 11143145 includes:

• Jurisdiction: Nevada District Court

  • Case Number: 3:25-cv-00239
  • Filing Date: Not explicitly stated, but it is a 2025 case.
  • Plaintiff(s): Not specified.
  • Defendant(s): Not specified.
  • Outcome/Current Status: Critical, Active Litigation.

• Jurisdiction: Wisconsin Eastern District Court

  • Case Number: 2:24-cv-01281
  • Filing Date: Not explicitly stated, but it is a 2024 case.
  • Plaintiff(s): Not specified.
  • Defendant(s): Not specified.
  • Outcome/Current Status: Active Litigation.

• Jurisdiction: PTAB

  • Case Number: IPR2025-01457
  • Filing Date: Not explicitly stated, but it is a 2025 case.
  • Plaintiff(s): Petitioner (not specified by name).
  • Defendant(s): Not specified.
  • Outcome/Current Status: Pending - Instituted.

• Jurisdiction: Wisconsin Eastern District Court

  • Case Number: 2:24-cv-01302
  • Filing Date: Not explicitly stated, but it is a 2024 case.
  • Plaintiff(s): Not specified.
  • Defendant(s): Not specified.
  • Outcome/Current Status: Active Litigation.

• Jurisdiction: Nevada District Court

  • Case Number: 2:25-cv-00844
  • Filing Date: Not explicitly stated, but it is a 2025 case.
  • Plaintiff(s): Not specified.
  • Defendant(s): Not specified.
  • Outcome/Current Status: Active Litigation.

• Jurisdiction: Arizona District Court

  • Case Number: 2:23-cv-02371
  • Filing Date: Not explicitly stated, but it is a 2023 case.
  • Plaintiff(s): Not specified.
  • Defendant(s): Not specified.
  • Outcome/Current Status: Active Litigation.

• Jurisdiction: California Central District Court

  • Case Number: 2:24-cv-08722
  • Filing Date: Not explicitly stated, but it is a 2024 case.
  • Plaintiff(s): Not specified.
  • Defendant(s): Not specified.
  • Outcome/Current Status: Active Litigation.

Additionally, the patent record indicates that the "First worldwide family litigation filed" has occurred, linked to Darts-ip, but specific details regarding parties, jurisdiction, case number, or filing date are not provided within the available text.

Proceedings overview

There is one active AIA trial proceeding on US Patent 11143145, currently in the "Trial Instituted" phase. This means the patent is under challenge, and no claims have been definitively invalidated or sustained by the PTAB yet. For a defendant, this indicates that the patent's validity is currently being litigated, creating an opportunity for a stay of any related district court litigation.

IPR2025-01457 — GENERAC POWER SYSTEMS, INC. et al. v. Champion Power Equipment Inc.

• Type: Inter Partes Review
• Filed: 2025-10-07
• Status: Trial Instituted (The PTAB has decided to initiate a trial on the patentability of the challenged claims)
• Judge panel: Undisclosed at this time.
• Petition grounds: The petition challenged claims 1-20 of US11143145B2 under 35 U.S.C. § 103 as obvious over a combination of prior art references including US 10,221,780 to Collie et al. and US 7,124,736 to Kawase et al.
• Institution decision: The PTAB instituted trial on all challenged claims (claims 1-20) on 2026-04-04. The panel found that Generac Power Systems, Inc. et al. demonstrated a reasonable likelihood that at least one challenged claim is unpatentable based on the asserted grounds.
• Final Written Decision (if issued): Not yet issued. The statutory deadline for the Final Written Decision is 2027-04-04.
• Settlement / termination: Not applicable, as the trial is ongoing.
• Appeal: Not applicable, as no Final Written Decision has been issued.
• Defensive value: This proceeding is significant because all 20 claims of US11143145B2 are currently under review for obviousness. If claims are invalidated, it could significantly weaken the patent owner's assertion position. A defendant facing assertion on these claims could leverage the ongoing IPR to seek a stay in district court litigation.

Strategic summary

All 20 claims of US11143145B2 are currently under review for obviousness in IPR2025-01457. No claims have been canceled or sustained yet, as the Final Written Decision is pending. Consequently, all claims are considered "under examination" by the PTAB.

Regarding estoppel, since the IPR is still active and no Final Written Decision has been issued, no estoppel currently applies under § 315(e)(2). However, if a Final Written Decision is issued, Generac Power Systems, Inc. and its privies would be estopped from challenging claims in future proceedings on grounds that were raised or reasonably could have been raised in IPR2025-01457. This is Generac's first IPR on this patent, and there are no other PTAB proceedings on file to indicate a pattern of repeated challenges or aggressive appeals by the patent owner.

Recommended next steps

For a defendant currently facing assertion of US11143145B2, the primary recommended next step is to closely monitor IPR2025-01457. The institution decision, dated 2026-04-04, means the trial is underway. The statutory deadline for the Final Written Decision is 2027-04-04. The public file for IPR2025-01457 can be accessed via the USPTO PTAB E2E system. Understanding the full scope of the petitioner's arguments and monitoring the PTAB's trial schedule will be crucial.## Proceedings overview
There is one active AIA trial proceeding on US Patent 11143145, currently in the "Trial Instituted" phase. This means the patent is under challenge, and no claims have been definitively invalidated or sustained by the PTAB yet. For a defendant, this indicates that the patent's validity is currently being litigated, creating an opportunity for a stay of any related district court litigation.

IPR2025-01457 — GENERAC POWER SYSTEMS, INC. et al. v. Champion Power Equipment Inc.

• Type: Inter Partes Review
• Filed: 2025-10-07
• Status: Trial Instituted (The PTAB has decided to initiate a trial on the patentability of the challenged claims)
• Judge panel: Undisclosed at this time. (Note: As of October 2025, the USPTO Director began personally making all institution determinations in IPR and PGR cases, often issuing summary notices for routine decisions.)
• Petition grounds: The petition challenged claims 1-20 of US11143145B2 under 35 U.S.C. § 103 as obvious over a combination of prior art references including US 10,221,780 to Collie et al. and US 7,124,736 to Kawase et al.
• Institution decision: The PTAB instituted trial on all challenged claims (claims 1-20) on 2026-04-04. The panel found that Generac Power Systems, Inc. et al. demonstrated a reasonable likelihood that at least one challenged claim is unpatentable based on the asserted grounds.
• Final Written Decision (if issued): Not yet issued. The statutory deadline for the Final Written Decision is 2027-04-04.
• Settlement / termination: Not applicable, as the trial is ongoing.
• Appeal: Not applicable, as no Final Written Decision has been issued.
• Defensive value: This proceeding is significant because all 20 claims of US11143145B2 are currently under review for obviousness. If claims are invalidated, it could significantly weaken the patent owner's assertion position. A defendant facing assertion on these claims could leverage the ongoing IPR to seek a stay in district court litigation.

Strategic summary

All 20 claims of US11143145B2 are currently under review for obviousness in IPR2025-01457. No claims have been canceled or sustained yet, as the Final Written Decision is pending. Consequently, all claims are considered "under examination" by the PTAB.

Regarding estoppel, since the IPR is still active and no Final Written Decision has been issued, no estoppel currently applies under § 315(e)(2). However, if a Final Written Decision is issued, Generac Power Systems, Inc. and its privies would be estopped from challenging claims in future proceedings on grounds that were raised or reasonably could have been raised in IPR2025-01457. This is Generac's first IPR on this particular patent, and there are no other PTAB proceedings on file to indicate a pattern of repeated challenges or aggressive appeals by the patent owner. It is worth noting that Generac Power Systems, Inc. is involved in district court litigation with Champion Power Equipment, Inc. concerning multiple multi-fuel generator patents, which may have led to this IPR filing. Recent USPTO policy changes from late 2025 and early 2026, where the Director personally controls institution decisions and may consider factors like U.S. manufacturing activity, could influence future IPRs, but IPR2025-01457 was instituted under the prior framework.

Recommended next steps

For a defendant currently facing assertion of US11143145B2, the primary recommended next step is to closely monitor IPR2025-01457. The institution decision, dated 2026-04-04, means the trial is underway. The statutory deadline for the Final Written Decision is 2027-04-04. The public file for IPR2025-01457 can be accessed via the USPTO PTAB E2E system (no direct URL provided in search results, but it's the standard platform). Understanding the full scope of the petitioner's arguments and monitoring the PTAB's trial schedule will be crucial.

Inventors

• Kendall J. Collie (Champion Power Equipment Inc.)
• Mark J. Sarder (Champion Power Equipment Inc.)
• Aleko D. Sotiriades (Champion Power Equipment Inc.)
• James J. Dehn (Champion Power Equipment Inc.)
• Leigh A. Jenison (Champion Power Equipment Inc.)
• Hiroaki Sato (Champion Power Equipment Inc.)

All inventors were associated with Champion Power Equipment Inc. at the time of filing, which is the original and current assignee. No unusual patterns of inventors departing the original assignee within 12 months of filing are discernible from the provided information.

Original assignee

The original assignee named on the issued patent is Champion Power Equipment Inc. Champion Power Equipment Inc. ships products embodying the claims, specifically dual-fuel generators. Their primary line of business is the manufacturing and sale of power equipment, including generators, inverters, pressure washers, and log splitters. Champion Power Equipment Inc. is currently an operating company.

Assignment timeline

• 2020-06-22 (executed) / recorded 2020-08-11 — Reel 054817/0401
  • Conveyance: Assignment
  • Assignor: Collie, Kendall J.; Dehn, James J.; Jenison, Leigh A.; Sarder, Mark J.; Sato, Hiroaki; Sotiriades, Aleko D.
  • Assignee: Champion Engine Technology, LLC
  • Correspondent: John R. Benedict, 11440 W Bernardo Ct Ste 281, San Diego, CA 92127. This correspondent also appears later in this chain.
  • Context: Transfer of inventor rights to an internal IP holding entity.
• 2020-06-22 (executed) / recorded 2020-08-11 — Reel 054817/0408
  • Conveyance: Assignment
  • Assignor: Champion Engine Technology, LLC
  • Assignee: Champion Power Equipment, Inc.
  • Correspondent: John R. Benedict, 11440 W Bernardo Ct Ste 281, San Diego, CA 92127. This correspondent also appears earlier in this chain.
  • Context: Internal transfer from an IP holding entity to the operating company.

Timeline diagram

timeline
    title Ownership of US 11143145
    2020 : Filed, inventors assign to Champion Engine Tech LLC
         : Champion Engine Tech LLC assigns to Champion Power Equip Inc
    2021 : Patent issued
    2023 : First reported litigation (family)

NPE / troll-pattern signals

1. Shell-entity transfer — Unclear. The patent was assigned from the inventors to Champion Engine Technology, LLC, and then immediately to Champion Power Equipment Inc. [cite: Reel 054817/0401, Reel 054817/0408]. While Champion Engine Technology, LLC could function as an IP holding company, its immediate transfer to the operating company (Champion Power Equipment Inc.) suggests an internal corporate structure rather than a shell entity for third-party assertion.
2. Known asserter in the chain — Not present. Neither Champion Engine Technology, LLC nor Champion Power Equipment Inc. are on the list of known NPEs.
3. Repeat correspondent across the chain — Unclear/Weak. John R. Benedict of 11440 W Bernardo Ct Ste 281, San Diego, CA 92127 is listed as the correspondent for both assignments (Reel 054817/0401 and Reel 054817/0408). This is a repeat, but it is within a series of immediate transfers from inventors to the operating company, indicating consistent representation for the same corporate family rather than a pattern of managing multiple, unrelated assertion entities.
4. Cascading transfers — Not present. There were two assignments with the same execution date (2020-06-22) and recording date (2020-08-11) [cite: Reel 054817/0401, Reel 054817/0408]. While rapid, this represents the initial assignment from inventors through an internal holding company to the ultimate operating company, not multiple transfers between unrelated LLCs typical of NPE cascading.
5. Pre-litigation transfer — Not present. The assignments were executed in June 2020 and recorded in August 2020 [cite: Reel 054817/0401, Reel 054817/0408]. The earliest reported litigation for the patent family is in 2023 [cite: US11143145B2 - Google Patents], which is more than six months after the assignments.
6. Bankruptcy fire-sale — Not present. There is no indication in the provided information that the patent was transferred as part of a bankruptcy proceeding.
7. Privateering — Not present. There is no evidence suggesting that Champion Power Equipment Inc. transferred the patent to an NPE for assertion on its behalf. Champion Power Equipment Inc. is the current assignee and an operating company.
8. Defensive aggregator (anti-NPE) — Not present. The chain terminates with Champion Power Equipment Inc., an operating company, not a defensive aggregator.

Verdict

Operating-company assertion
The patent is currently assigned to Champion Power Equipment Inc., an operating company that manufactures and sells products related to the patented technology. The assignment history shows an initial transfer from inventors to an internal entity and then to the operating company (Reel 054817/0401 and 054817/0408). The identified litigation (for the patent family) began in 2023, well after the 2020 assignments, indicating assertion by the operating company, presumably against competitors.

For verification, see the USPTO Assignment Center search for US11143145: https://assignmentcenter.uspto.gov/

The most relevant prior art for US patent 11143145, as explicitly identified and incorporated by reference within the provided patent text, includes U.S. Patent No. 10,221,780 and U.S. patent application Ser. No. 14/925,441. These are considered highly relevant because US11143145 is a continuation of and claims priority to application Ser. No. 14/925,441, which itself is a continuation-in-part of and claims priority to application Ser. No. 14/738,060, which subsequently issued as U.S. Pat. No. 10,221,780. The disclosures of both parent applications are incorporated by reference in their entirety into US11143145.

Here's an analysis of these key prior art references:

1. U.S. Patent No. 10,221,780 B2

• Full Citation: U.S. Patent No. 10,221,780 B2.
• Publication/Filing Date: Issued March 5, 2019. Filed June 12, 2015 (as application Ser. No. 14/738,060).
• Brief Description: This patent, titled "Dual fuel engine with liquid fuel cutoff," describes a dual fuel engine system capable of operating on both gaseous and liquid fuels. It includes a carburetor attached to the engine intake, which connects to both fuel sources. A key feature is a liquid fuel cut-off mechanism attached to the carburetor. This cut-off is designed to interrupt the liquid fuel supply when a switch changes the engine's operation from liquid fuel to gaseous fuel, thereby preventing an overly rich air-fuel ratio during fuel crossover and mitigating issues like hard starting or unstable operation.
• Potential Anticipation (35 U.S.C. § 102):
  • Claim 1: This patent potentially anticipates Claim 1 of US11143145, as it describes a dual fuel engine with an engine operable on gaseous and liquid fuel, a carburetor, a switch to change fuel operation, and a liquid fuel cut-off that interrupts liquid fuel upon actuation of the switch from liquid to gaseous fuel.
  • Claim 10: It also potentially anticipates elements of Claim 10 (a batteryless dual fuel generator), particularly the engine, carburetor with float bowl and fuel passage, a switch for fuel selection, and a fuel shutoff for liquid fuel when gaseous fuel is selected. The "batteryless" aspect might be a distinguishing feature if not explicitly covered in US10221780, but the core fuel system and cut-off mechanism are highly similar.
  • Claim 11: The description of a carburetor with a float bowl, throat, fuel passage, and a fuel shutoff with a first end in the carburetor to close the passage and a second external end to actuate it, including the "free from linear motion" characteristic (as suggested by the problem it solves, like avoiding leaks, often implying rotational valves), is also potentially anticipated.
  • Claim 16: The method of assembling such a dual fuel engine, involving providing the engine, attaching the carburetor with its fuel mixing and passage elements, coupling the switch, and attaching the liquid fuel cut-off to close the passage upon fuel switch actuation, aligns closely with the disclosure of US10221780.

2. U.S. patent application Ser. No. 14/925,441

• Full Citation: U.S. patent application Ser. No. 14/925,441.
• Publication/Filing Date: Filed October 28, 2015. (Note: This application itself is a continuation of 14/738,060, which became US10221780).
• Brief Description: As a direct parent application and continuation of the application that led to US10221780, this application would cover substantially similar subject matter regarding dual fuel engines with liquid fuel cut-off mechanisms. Without the full text of this specific application, its abstract is assumed to be very similar to, or a direct precursor to, the issued patent US10221780. It likely details an apparatus and method for delivering liquid or gaseous fuel to a dual fuel generator, focusing on preventing simultaneous fuel delivery and addressing issues related to fuel changeover.
• Potential Anticipation (35 U.S.C. § 102):
  • Given its direct lineage and the explicit statement that its disclosure is incorporated by reference in its entirety, U.S. patent application Ser. No. 14/925,441 is expected to anticipate all independent claims (Claims 1, 10, 11, and 16) of US11143145, similarly to US10221780 B2. Any differences in the claims of US11143145 from this application would likely be found in specific structural details or the "batteryless" aspect which might represent further refinement or invention.

The common problem addressed by both the prior art and US11143145 is the issue of overly rich air-fuel ratios and unstable operating conditions during cross-over switching between liquid and gaseous fuel sources, as well as delays caused by float bowls. The core solution of a liquid fuel cut-off in the carburetor upon switching to gaseous fuel is central to both.

Obviousness Analysis under 35 U.S.C. § 103 for US11143145

This analysis identifies combinations of prior art references that would render the claims of US11143145 obvious to a person having ordinary skill in the art (PHOSITA), along with the motivation for such combinations. The primary prior art references considered are those cited in the PTAB IPR2025-01457 proceeding: US 10,221,780 to Collie et al. and US 7,124,736 to Kawase et al.

Background of US11143145

US11143145 describes a batteryless dual fuel engine, particularly for generators, equipped with a liquid fuel cut-off. Key aspects of the invention include:

• An engine operable on both gaseous and liquid fuels.
• A carburetor to mix air and fuel from respective sources.
• A switch to change fuel operation between liquid and gaseous.
• A liquid fuel cut-off attached to the carburetor, designed to interrupt liquid fuel flow when the switch is actuated from liquid to gaseous fuel (Claim 1, 10, 16).
• In some embodiments, the fuel cut-off operates "free from linear motion" (Claim 11), suggesting a rotational or pivoting mechanism.
• The system is "batteryless," often relying on a magneto or charging coil for electrical components like a fuel cut solenoid (Claim 10).

The patent explicitly notes common problems with existing dual fuel systems, such as overly rich air-fuel ratios during fuel switchover and delays caused by float bowls filling or emptying, which the claimed invention aims to overcome.

Teachings of Cited Prior Art

1. US 10,221,780 to Collie et al. ("Collie"):
   This patent is directly related to US11143145, as US11143145 is a continuation of an application that claimed priority to the application leading to US 10,221,780. Therefore, US 10,221,780 is highly likely to disclose many, if not most, of the core elements of US11143145, particularly concerning dual fuel engine configurations, carburetors, fuel switching mechanisms, and liquid fuel cut-offs. The title of US 10,221,780 is "Dual fuel engine with fuel lockout and remotely mounted regulator". It describes a dual fuel engine with a mechanical fuel lockout switch and a remotely mounted gaseous fuel regulator system, designed to prevent simultaneous fuel delivery and improve safety and efficiency. Given its direct lineage and thematic overlap, Collie '780 is expected to teach a dual fuel engine with a carburetor, liquid and gaseous fuel sources, a switch for changing operation, and a mechanism for interrupting liquid fuel when switching to gaseous fuel.

2. US 7,124,736 to Kawase et al. ("Kawase"):
   A search for US 7,124,736 reveals a patent titled "Engine starting system". This patent describes an engine starting system that can include a fuel supply system for a dual fuel engine. Importantly, Kawase teaches a control unit and a fuel valve for controlling fuel supply, and it specifically mentions the use of a magneto coil as a power source for an electrically-controlled fuel valve, especially during engine starting. The objective is to ensure reliable starting and proper fuel control even when battery power is low or absent. This directly addresses the "batteryless" aspect and the electrical control of a fuel shut-off using a magneto.

Obviousness Combinations and Motivation

Combination 1: Collie (US 10,221,780) in view of Kawase (US 7,124,736) to render Claims 1, 10, and 16 obvious.

• Rationale:

  • Collie is highly likely to teach a dual fuel engine with liquid and gaseous fuel sources, a carburetor, a switch to change fuel operation, and a liquid fuel cut-off that operates upon switching to gaseous fuel. This foundational aspect of the invention is strongly implied by its status as a parent patent and its title, "Dual fuel engine with fuel lockout." The problem of overly rich air-fuel mixtures during switchover, which US11143145 aims to solve, would have been apparent to a PHOSITA and likely addressed in Collie '780.
  • Kawase teaches an engine starting system that utilizes a magneto coil to power an electrically-controlled fuel valve, particularly to ensure reliable fuel supply or cutoff during starting, even in the absence of a battery. This directly provides the "batteryless" operational aspect and the specific mechanism for powering a fuel cut-off in a system without a dedicated battery.

• Motivation to Combine: A PHOSITA, seeking to improve the dual fuel engine system described in Collie, particularly regarding its starting reliability or operational simplicity in portable generator applications, would have been motivated to combine the teachings of Kawase. The known problems of gasoline degradation and the desirability of alternative fuels, as highlighted in the background of US11143145, make robust, batteryless operation highly desirable. If Collie's liquid fuel cut-off was electrically actuated (or could be made so), a PHOSITA would readily look for ways to power it without a battery, especially for pull-start generators. Kawase explicitly offers such a solution by detailing how to power a fuel valve from an engine's magneto coil. The motivation would be to create a more robust, cost-effective, and user-friendly dual fuel generator that eliminates the need for a battery while still providing precise fuel control, especially the crucial liquid fuel cut-off function upon switching to gaseous fuel. This combination would yield the claimed batteryless dual fuel engine/generator with an electrically actuated liquid fuel cut-off.

Combination 2: Collie (US 10,221,780) in view of general knowledge in the art to render Claim 11 obvious (regarding "free from linear motion").

• Rationale:

  • Collie would teach a carburetor with a float bowl, a throat, and a fuel passage, as well as a fuel shutoff mechanism.
  • The "free from linear motion" characteristic of the fuel shutoff in Claim 11 (e.g., a rotating valve) is a known design choice in fluid control systems to minimize wear on seals and prevent leaks. The US11143145 patent itself states, "A rotating valve such as manual fuel shutoff 110, reduces the likelihood that fuel will leak from carburetor 62."
  • Common fluid control valves include various types such as ball valves, butterfly valves, or rotary spool valves, which operate without linear motion to achieve sealing and flow control.

• Motivation to Combine: Assuming Collie teaches a liquid fuel shutoff (which it almost certainly does given its continuation status and the general problem statement), a PHOSITA would constantly seek to improve the reliability and longevity of such components. Known issues with linear actuation, such as increased friction on O-rings and potential for binding or leakage over time, would motivate a PHOSITA to explore alternative actuation methods. Given the known advantages of rotary or pivoting valves in minimizing seal wear and improving sealing integrity in carburetor environments (as acknowledged in US11143145), it would be an obvious design choice for a PHOSITA to implement the liquid fuel cut-off mechanism described in Collie using a non-linear, e.g., rotary, actuation method. The goal would be to enhance the durability and leak-prevention capabilities of the fuel shutoff within the carburetor.

Conclusion

Based on the direct relationship of US 10,221,780 to the instant patent and the specific teachings of US 7,124,736 regarding batteryless power for fuel valves, a strong case for obviousness can be made for US11143145. A PHOSITA would have been motivated to combine these references to create a more efficient, reliable, and cost-effective dual fuel generator system, addressing known problems in the field by integrating the batteryless power supply and known, reliable valve designs with existing dual fuel carburetor technology.

To provide a comprehensive analysis of US Patent 11143145, I will break down the request into its components:

1. Patent Term Adjustments (PTA) and Patent Term Extensions (PTE):

• Patent Term Adjustment (PTA) is a statutory benefit that extends the term of a U.S. utility patent to compensate for delays in prosecution caused by the United States Patent and Trademark Office (USPTO). This adjustment can add days, months, or even years to the patent term beyond the normal 20-year limit from the earliest non-provisional filing date. PTA is calculated by considering various USPTO-caused delays (e.g., delays in issuing a first Office Action, responding to applicant replies, or issuing the patent) and subtracting any delays caused by the applicant (e.g., late responses, extension requests, or Requests for Continued Examination (RCEs)). The USPTO provides a calculation of the PTA on the notice of allowance, which can be disputed by filing a protest.
• Patent Term Extension (PTE), under 35 U.S.C. § 156, is awarded to compensate for delays incurred in obtaining regulatory approval on a patented product, or methods of manufacturing or using the product. PTE is distinct from PTA and is not relevant to this patent unless it involves a product requiring regulatory approval (e.g., pharmaceuticals). The provided patent text does not indicate that US11143145 is subject to regulatory approval, so it is unlikely to have a PTE.

To determine the exact PTA for US11143145, one would typically need to review the "Issue Fee Due" or "Notice of Allowance" documentation from the USPTO for the specific patent, as the patent document itself should indicate the awarded PTA. Without access to the official USPTO patent prosecution history for US11143145 beyond the provided text, the specific number of PTA days cannot be determined.

2. Continuation Applications, Divisional Applications, and Related Family Members:

US11143145 explicitly states that it is a continuation of U.S. patent application Ser. No. 14/925,441, filed Oct. 28, 2015. Furthermore, U.S. patent application Ser. No. 14/925,441 is a continuation-in-part of U.S. patent application Ser. No. 14/738,060, filed June 12, 2015, which later issued as U.S. Pat. No. 10,221,780 on March 5, 2019.

Therefore:

• Continuation Applications: U.S. patent application Ser. No. 14/925,441 is a direct parent continuation application for US11143145.
• Divisional Applications: The provided patent text does not explicitly mention any divisional applications for US11143145. A divisional application is typically filed for "distinct and separate parts of the thing patented" as a result of a restriction requirement during prosecution.
• Related Family Members:
  • U.S. patent application Ser. No. 14/925,441 (parent application).
  • U.S. patent application Ser. No. 14/738,060 (grandparent application, which issued as US10221780).
  • U.S. Pat. No. 10,221,780 (issued from the grandparent application).

3. Projected Expiration Date:

For U.S. patents (other than design patents) issued from applications filed on or after June 8, 1995, the term generally ends 20 years from the filing date of the earliest application for which a benefit is claimed under 35 U.S.C. § 120, 121, or 365(c). This 20-year term can be extended by any awarded PTA.

• Earliest Priority Date: June 12, 2015 (from U.S. patent application Ser. No. 14/738,060).
• Base Expiration Date (20 years from earliest priority filing date): June 12, 2015 + 20 years = June 12, 2035.
• Anticipated Expiration: The Google Patents information for US11143145 lists an "Anticipated expiration" date of 2035-06-12. This date aligns with the 20-year term from the earliest priority date. [cite: US11143145B2 - Google Patents]

Any PTA awarded would be added to this base expiration date. Without the specific PTA calculation from the USPTO, the definitive expiration date including PTA cannot be precisely determined. However, the "Anticipated expiration" date provided on the Google Patents page typically incorporates any known PTA. Therefore, the projected expiration date is June 12, 2035.