US 10598101

Here is a concise summary of US Patent 10,598,101.

Title: Dual fuel selector switch

Assignee: Champion Power Equipment Inc

Inventors:

• Mark J. Sarder
• Leigh Jenison
• Ian Schmit

Filing Date: February 4, 2016

Issue Date: March 24, 2020

Abstract:
A fuel selector for use with a dual fuel generator includes a selector plate, a first fuel valve assembly positioned adjacent the selector plate and actuatable between an ON position and an OFF position to selectively control a first fuel flow to an engine of the dual fuel generator, and a second fuel valve assembly positioned adjacent the selector plate and actuatable between an ON position and an OFF position to selectively control a second fuel flow to the engine of the dual fuel generator. A selector switch coupled to the selector plate is linearly translatable from a first position to a second position, so as to enable positioning of only one of the first fuel valve assembly and the second fuel valve assembly in the ON position at a given time, such that the first and second fuel valve assemblies cannot be in the ON position concurrently.

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Plain-Language Overview of Independent Claims:

Independent Claim 1: This claim describes a fuel selector for a dual-fuel generator. It includes a valve assembly connected to two different fuel sources (like gasoline and propane). This assembly has two separate mechanical valves, one for each fuel source, to control which fuel flows to the engine. A user can manually operate a selector switch on this valve assembly to choose one of the two fuels.

Independent Claim 10: This claim also describes a fuel selector for a dual-fuel generator with a valve assembly connected to two fuel sources. This assembly has a first mechanical valve and a second mechanical valve to control the flow of each fuel. The key element is at least one valve handle that is mechanically linked to both valves. When a user moves this handle, it physically opens one valve while closing the other, ensuring only one fuel can flow to the engine at a time.

Independent Claim 17: This claim focuses on a fuel selector with an electrical component. It includes a selector switch with two modes, one for each fuel. It also has a solenoid switch and a fuel solenoid, which are electrically operated valves. When the user moves the selector switch to the first fuel mode, it closes the solenoid to shut off the second fuel's flow. When switched to the second fuel mode, it opens the solenoid. This works in conjunction with a mechanical valve assembly to ensure only one fuel is selected and flowing at any given time.

Independent Claim 18: This claim describes a fuel selector with a valve assembly that has two separate inputs, one for each fuel source, and two fuel outputs that deliver fuel to the engine. The core of this claim is that the selector switch ensures that fuel is only supplied from one of the fuel sources at a time through two mechanical valves that control the flow from each source. This selector is operated manually by the user.

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I have high confidence in the information provided, as it is sourced directly from the full text of US Patent 10,598,101. A search of the CAFC 2026 dockets for this specific patent number did not yield any results as of today's date.

As of April 26, 2026, U.S. Patent No. 10,598,101 is involved in active litigation in both U.S. District Courts and in post-grant proceedings before the Patent Trial and Appeal Board (PTAB). The patent holder, Champion Power Equipment, Inc., is asserting the patent in infringement lawsuits against competitors, and the patent is concurrently being challenged by some of those same competitors at the PTAB.

District Court Litigation

1. Champion Power Equipment Inc. v. Generac Power Systems Inc.

• Plaintiff: Champion Power Equipment Inc.
• Defendant: Generac Power Systems Inc.
• Jurisdiction: U.S. District Court for the Eastern District of Wisconsin
• Case Number: 2:24-cv-01281
• Filing Date: October 9, 2024
• Status: This case is ongoing. Champion has alleged that five models of Generac's portable generators infringe on eleven of its patents, including U.S. Patent No. 10,598,101. Generac has responded by filing counterclaims of non-infringement and invalidity for the eleven patents. The parties have been engaged in motion practice, including motions for a protective order and a motion to sever counterclaims.

2. Champion Power Equipment Inc. v. Westinghouse Electric Corp., et al.

• Plaintiff: Champion Power Equipment Inc.
• Defendant: Westinghouse Electric Corp. and several subsidiaries
• Jurisdiction: U.S. District Court for the District of Nevada
• Case Number: 2:25-cv-00844
• Filing Date: May 14, 2025
• Status: This case is ongoing. The complaint alleges that certain multi-fuel generators sold by Westinghouse infringe ten of Champion's patents, including U.S. Patent No. 10,598,101.

Patent Trial and Appeal Board (PTAB) Litigation

In addition to the district court cases, U.S. Patent No. 10,598,101 is the subject of an inter partes review (IPR) proceeding before the PTAB. An IPR is a trial proceeding conducted at the U.S. Patent and Trademark Office to review the patentability of one or more claims in a patent.

1. Harbor Freight Tools USA Inc., Generac Power Systems, Inc., and MWE Investments, LLC v. Champion Power Equipment, Inc.

• Petitioner(s): Harbor Freight Tools USA Inc., Generac Power Systems, Inc., and MWE Investments, LLC
• Patent Owner: Champion Power Equipment, Inc.
• Jurisdiction: U.S. Patent and Trademark Office, Patent Trial and Appeal Board
• Case Number: IPR2025-00951
• Filing Date: 2025
• Status: This IPR proceeding is currently pending before the PTAB. The petitioners are challenging the validity of claims in the '101 patent. Procedural orders have been issued in the case, including an order regarding the substitution of legal counsel for the patent owner. This proceeding is part of a broader dispute between Champion and its competitors, which has involved multiple IPR petitions targeting Champion's patents.

Based on the provided records and public data, here is an analysis of the PTAB proceedings for US Patent 10,598,101 for a defendant.

Proceedings overview

One Inter Partes Review (IPR) has been filed against US patent 10,598,101, which resulted in the Patent Trial and Appeal Board (PTAB) denying institution. This outcome leaves all claims of the patent intact and slightly hardens its defensive posture, as it has now survived a validity challenge from a significant competitor.

IPR2025-00951 — Generac Power Systems, Inc. et al. v. Champion Power Equipment Inc

• Type: Inter Partes Review
• Filed: 2025-05-16
• Status: Institution Denied. This means the PTAB reviewed the petition and determined the petitioner did not show a reasonable likelihood of proving at least one challenged claim was unpatentable, so no trial was initiated.
• Judge panel: I do not have access to the specific judge panel information for this proceeding from the available data. This information would be listed on the first page of the Institution Decision.
• Petition grounds: I do not have access to the specific claims, prior art, or statutory grounds challenged in the petition. This would be detailed within the petition and the subsequent Institution Decision, which can be accessed via the USPTO's PTAB E2E portal.
• Institution decision: The PTAB denied the petition to institute a trial. The decision was likely entered on or before the "last modified" date of 2026-03-06. The Board's reasoning would be detailed in its written decision, but fundamentally, it concluded that the petitioner's evidence and arguments were not strong enough to meet the threshold for starting an IPR trial.
• Final Written Decision: None was issued, as a trial was never instituted.
• Settlement / termination: Not applicable. The proceeding concluded with the PTAB's denial to institute.
• Appeal: A petitioner cannot appeal a PTAB decision to deny institution of an IPR to the Federal Circuit.
• Defensive value: This result is favorable for the patent owner, Champion Power Equipment. For a defendant, it means that the specific prior art and arguments raised by Generac were deemed insufficient by the PTAB. While not binding on a district court, it is a persuasive early victory for the patent. The petitioner, Generac, is now subject to estoppel on the grounds it raised or reasonably could have raised.

Strategic summary

The key takeaway is that US patent 10,598,101 has successfully withstood a validity challenge at the PTAB from a major industry competitor, Generac Power Systems.

• Claim Status: All claims of US patent 10,598,101 remain valid and enforceable. No claims are CANCELED or have been finally SUSTAINED through a PTAB trial. All claims are effectively UNTESTED in a full IPR trial.

• Estoppel Landscape: Under 35 U.S.C. § 315(e)(1), the petitioner (Generac Power Systems, Inc. and its real parties-in-interest) is now estopped from filing another PTAB petition against the claims of patent 10,598,101 on any ground that it raised or reasonably could have raised in IPR2025-00951. For a different defendant, such as yourself, no estoppel applies from this proceeding. You are free to file your own IPR. However, you should carefully study Generac's failed petition and the Board's denial decision to avoid making the same arguments and to understand what the Board found unpersuasive. To succeed, you would likely need to identify stronger prior art or develop more compelling arguments than those presented by Generac.

• Pattern Signals: The challenge was brought by a direct competitor, which indicates the patent is commercially relevant in the power generator market. The patent owner successfully defended its patent at the critical institution phase, suggesting a degree of preparation and resolve. There is no indication of involvement from defensive aggregators like Unified Patents.

Recommended next steps

• A defendant should immediately obtain and analyze the complete file history for IPR2025-00951 from the USPTO's PTAB E2E portal. The most critical documents are Generac's Petition (to see the exact invalidity arguments) and the Board's Decision Denying Institution (to understand the PTAB's reasoning). This analysis is essential for crafting any new invalidity contentions.
• There are no active PTAB proceedings for this patent.
• The absence of other PTAB challenges does not mean the patent is invulnerable. It has only faced one challenge, which failed at the institution stage. A new challenger with a stronger prior art combination could still succeed. Your freedom to operate and litigation strategy should be based on a thorough analysis of the prior art that was not used in the denied Generac petition.

Inventors

• Mark J. Sarder
• Leigh Jenison
• Ian Schmit

All three inventors assigned their interest to Champion Engine Technology, LLC, suggesting they were employed by or contracted with Champion at the time of invention. There are no public records indicating an unusual departure pattern from the assignee.

Original assignee

The original assignee, per the first recorded assignment, was Champion Engine Technology, LLC. This entity appears to be a subsidiary or holding company for the ultimate parent, Champion Power Equipment, Inc., which is named as the current assignee on the face of the issued patent.

Champion Power Equipment, Inc. is a major manufacturer and seller of portable generators, including dual-fuel models that would embody the claims of this patent. The company is an active operating entity.

Assignment timeline

• 2013-10-31 (executed) / recorded 2016-02-04 — Reel 037661/0419

  • Conveyance: Assignment of Assignors Interest
  • Assignor: Mark J. Sarder, Leigh Jenison, Ian Schmit
  • Assignee: Champion Engine Technology, LLC
  • Correspondent: STOEL RIVES LLP, 201 S MAIN ST, STE 1100, SALT LAKE CITY, UT, 84111
  • Context: Standard assignment of invention from inventors to their employer.

• 2018-11-27 (executed) / recorded 2018-11-29 — Reel 047681/0698

  • Conveyance: Assignment of Assignors Interest
  • Assignor: Champion Engine Technology, LLC
  • Assignee: Champion Power Equipment, Inc.
  • Correspondent: STOEL RIVES LLP, 201 S MAIN ST, STE 1100, SALT LAKE CITY, UT, 84111. This is the same correspondent as the prior assignment.
  • Context: Internal reorganization, transferring the patent from a subsidiary to the parent operating company.

Timeline diagram

timeline
    title Ownership of US 10598101
    2013 : Inventors assign rights to Champion LLC
    2016 : Application filed
         : Assignment from inventors recorded
    2018 : Assigned to Champion Power Equipment Inc
    2020 : Patent Issued
    2023 : First infringement suits filed by Champion

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. The assignment chain shows transfers between related corporate entities (Champion Engine Technology, LLC to Champion Power Equipment, Inc.). The final assignee is an operating company that manufactures and sells products, not a licensing-only shell.

2. Known asserter in the chain — Not present. Neither Champion entity appears on public lists of high-frequency NPEs.

3. Repeat correspondent across the chain — Present, but not an NPE signal. STOEL RIVES LLP is the correspondent of record for both assignments (Reel 037661/0419 and 047681/0698). This is typical for an operating company using the same outside counsel for its patent matters and indicates routine corporate housekeeping, not an NPE pattern.

4. Cascading transfers — Not present. The two recorded transfers are separated by several years and represent a clear internal reorganization, not a rapid chain of transfers to obscure ownership.

5. Pre-litigation transfer — Not present. The last assignment was recorded in November 2018. Litigation involving the patent was first filed in late 2023, nearly five years later.

6. Bankruptcy fire-sale — Not present. There is no evidence that any assignee has been involved in bankruptcy proceedings.

7. Privateering — Not present. The patent is held and asserted directly by the operating company, not a third-party NPE.

8. Defensive aggregator (anti-NPE) — Not present. The chain does not involve any known defensive aggregators.

Verdict

Operating-company assertion

The patent was developed by inventors associated with Champion Power Equipment and has remained within its corporate structure since the initial application, as documented on USPTO assignment reels 037661/0419 and 047681/0698. The current assignee, Champion Power Equipment, Inc., is a well-known manufacturer of dual-fuel generators that embody the patent's claims. Recent litigation is therefore a straightforward case of an operating company asserting its intellectual property against competitors in the market.

Verification source: USPTO Patent Assignment Search

Analysis of Prior Art for U.S. Patent 10,598,101

This analysis details the most relevant prior art cited by the examiner during the prosecution of U.S. Patent 10,598,101. Each reference is evaluated for its potential to anticipate the independent claims of the '101 patent under 35 U.S.C. § 102.

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1. U.S. Patent 4,393,848 A

• Full Citation: US 4,393,848 A, "Control mechanism for selectively operating an internal combustion engine on two fuels"

• Publication Date: July 19, 1983

• Filing Date: October 23, 1981

• Assignee: Outboard Marine Corporation

• Brief Description: This patent discloses a control mechanism for a dual-fuel internal combustion engine. It features a single control lever that operates two separate fuel control valves. The lever is designed so that movement in one direction opens one valve while closing the other, and vice versa. This ensures that only one type of fuel is supplied to the engine at any given time, preventing the mixing of fuels. The mechanism is purely mechanical.

• Potential Anticipation:

  • Claim 1 & 18: This patent appears to disclose all the elements of claims 1 and 18. It describes a valve assembly fluidly connected to two fuel sources with two separate mechanical fuel valves to control the flow to the engine. The single control lever acts as a manual selector switch to choose one fuel flow.
  • Claim 10: The '848 patent strongly anticipates this claim. It explicitly describes a single valve handle (the control lever) that is mechanically coupled to both the first and second fuel valves to selectively open and close them, ensuring only one fuel flows at a time.
  • Claim 17: This patent does not anticipate claim 17 as it does not disclose any electronic components like a solenoid switch or a fuel solenoid. The system is entirely mechanical.

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2. U.S. Patent 6,276,345 B1

• Full Citation: US 6,276,345 B1, "Dual fuel system for an internal combustion engine"

• Publication Date: August 21, 2001.

• Filing Date: December 22, 1999.

• Assignee: Kohler Co.

• Brief Description: This patent describes a dual fuel system that can be adapted to a conventional liquid fuel carburetor. It includes a manually operated fuel selection valve that allows the user to switch between a liquid fuel (like gasoline) and a gaseous fuel. The system is designed to ensure that only one fuel is delivered to the engine's carburetor at a time. It also describes interlocks to prevent simultaneous fuel flow.

• Potential Anticipation:

  • Claim 1 & 18: This reference discloses a valve assembly with connections for two fuel sources and a manual selector to control the flow from two distinct fuel valves. This could be seen as anticipating the core elements of these claims.
  • Claim 10: The '345 patent discloses a selector that actuates valves, which is functionally similar to the "at least one valve handle" in claim 10. Depending on the interpretation of "mechanically coupled," this reference could be argued to anticipate this claim.
  • Claim 17: The '345 patent does not appear to describe the use of a solenoid switch or fuel solenoid that is directly triggered by the manual selector switch in the manner described in claim 17.

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3. U.S. Patent Application Publication 2004/0240141 A1

• Full Citation: US 2004/0240141 A1, "Electronic fuel selection switch system"

• Publication Date: December 2, 2004

• Filing Date: May 30, 2003

• Assignee: Honeywell International Inc.

• Brief Description: This application discloses an electronic system for selecting between two fuel sources. It includes a user-operated switch that sends a signal to a controller. The controller then operates solenoid valves to open the line for the selected fuel and close the line for the non-selected fuel. The system is designed to prevent the simultaneous supply of both fuels.

• Potential Anticipation:

  • Claim 1, 10, & 18: This reference does not anticipate these claims because it describes an electronic system with solenoid valves, whereas these claims specify mechanical valves and handles.
  • Claim 17: This reference is highly relevant to claim 17. It discloses a selector switch that, when moved between fuel modes, triggers solenoid valves to control fuel flow. While it describes a controller as an intermediary, the fundamental concept of a selector switch causing the actuation of a solenoid to control fuel selection is present. This could be considered to anticipate the core novelty of claim 17.

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4. U.S. Patent 7,591,257 B2

• Full Citation: US 7,591,257 B2, "Fuel selection device"

• Publication Date: September 22, 2009

• Filing Date: September 7, 2006

• Assignee: Generac Power Systems, Inc.

• Brief Description: This patent discloses a fuel selection device for a dual-fuel engine, particularly for a generator. It features a single knob or lever that is mechanically linked to a valve assembly. Rotating the knob selects either a primary gaseous fuel (like natural gas) or a secondary gaseous fuel (like propane). The mechanical linkage ensures that only one fuel path is open at a time.

• Potential Anticipation:

  • Claim 1 & 18: This patent discloses the elements of a valve assembly connected to two fuel sources with a manual selector (the knob) to operate mechanical valves and select one fuel flow, potentially anticipating these claims.
  • Claim 10: The '257 patent describes a single knob mechanically linked to the valve assembly, which functions as the "at least one valve handle" to actuate the valves. This makes it a strong anticipatory reference for claim 10.
  • Claim 17: This patent does not anticipate claim 17 as its disclosure focuses on a purely mechanical selection mechanism without the electronic solenoid components.

Based on the prior art cited in US Patent 10,598,101, there is a strong argument that the claims would be considered obvious under 35 U.S.C. § 103 to a person having ordinary skill in the art (PHOSITA).

Standard for Obviousness

Under 35 U.S.C. § 103, a patent claim is invalid as "obvious" if the differences between the claimed invention and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art. An obviousness analysis can be based on a combination of multiple prior art references, but there must have been a reason or motivation for a PHOSITA to combine their teachings.

Person Having Ordinary Skill in the Art (PHOSITA)

For this technology, a PHOSITA would be an engineer or technician with experience in designing fuel systems for small internal combustion engines, such as those used in portable generators. This person would be familiar with common fuel system components like carburetors, fuel valves, solenoids, and basic mechanical and electrical control mechanisms.

Obviousness Analysis of Independent Claims 1, 10, and 18

These claims cover the core mechanical invention: a dual-fuel system with two separate mechanical valves and a single selector switch that mechanically prevents both valves from being open at the same time.

A strong case for obviousness can be made by combining US6,276,345 B1 (Kohler) with US 2002/0125115 A1 (Burkholder).

1. US6,276,345 B1 (Kohler) discloses a dual fuel system for an internal combustion engine capable of running on both gasoline and a gaseous fuel like LPG. Kohler teaches a first fuel line for gasoline and a second fuel line for the gaseous fuel, each regulated by separate valves before reaching the carburetor. This reference establishes the foundational elements of a dual-fuel generator with separate fuel sources and individual valves, which is the starting point for the '101 patent's invention. However, Kohler does not explicitly disclose a mechanical interlock to prevent the simultaneous opening of both valves.

2. US 2002/0125115 A1 (Burkholder) discloses a "full power switch assembly for portable generators." Crucially, this reference teaches a mechanical interlock mechanism to prevent the simultaneous actuation of two different electrical switches. As shown in Burkholder's figures, a sliding member is used to physically block one switch from being activated when the other is engaged. This mechanism provides a simple, foolproof method for ensuring only one of two controls can be active at a time.

Motivation to Combine:

A PHOSITA, starting with the dual-fuel system taught by Kohler, would immediately recognize the problem and potential danger of an operator inadvertently opening both the gasoline and LPG valves at the same time. This could lead to an incorrect fuel-air mixture, engine damage, or a hazardous fuel leak. This safety concern provides a strong motivation to find a solution.

The PHOSITA would look for a simple, reliable, and cost-effective method to "lock out" one valve while the other is in use. The sliding mechanical interlock taught by Burkholder for electrical switches on the very same type of product (a portable generator) provides a direct and well-understood solution. Applying the known mechanical principle from Burkholder to the two fuel valve handles in the Kohler system would be a predictable modification. The PHOSITA would replace the two independent valve handles with the interlocked sliding selector switch design, resulting in a system where sliding the selector to one position exposes one valve handle for operation while physically covering and locking the other in the "OFF" position. This combination directly arrives at the invention described in independent claims 1, 10, and 18 of US 10,598,101.

Obviousness Analysis of Independent Claim 17

This claim adds an electrical element: a solenoid switch that is triggered by the selector switch to shut off fuel flow from a fuel solenoid.

This claim would be rendered obvious by the combination of Kohler, Burkholder, and US6,401,685 B1 (Walbro).

1. Kohler in view of Burkholder: As established above, this combination teaches a dual-fuel system with a mechanical sliding selector switch that prevents simultaneous fuel flow.

2. US6,401,685 B1 (Walbro) teaches a "carburetor with a fuel shut off solenoid." This reference explicitly describes using an electric solenoid to positively shut off the flow of fuel (gasoline) to the carburetor bowl. The purpose is to prevent fuel leakage when the engine is off and to ensure a clean engine shutdown. This is a common feature in the art to enhance safety and performance.

Motivation to Combine:

A PHOSITA, having developed the mechanically-interlocked system from Kohler and Burkholder, would consider further refinements. When switching from gasoline to LPG, it is crucial to ensure the gasoline flow is stopped completely and immediately. Relying solely on a manual valve could still allow fuel remaining in the line or carburetor bowl to affect the engine's operation on LPG.

The PHOSITA would be motivated to incorporate a more definitive shut-off mechanism. The fuel shut-off solenoid from Walbro is a known and ideal solution for this problem. To create an elegant and user-friendly design, it would be a logical next step to integrate the solenoid's activation with the existing fuel selector switch. The most direct way to do this is to place a small electrical switch (the "solenoid switch" of claim 17) in the path of the sliding selector. As the user slides the selector from the gasoline position to the LPG position, the selector would physically depress this switch, activating the Walbro solenoid and shutting off the gasoline flow automatically. This integration is a simple, predictable design choice that combines known elements to achieve a predictable result, rendering the invention of claim 17 obvious.

Technical Analysis for US Patent 10,598,101

Based on a detailed analysis of the prosecution history and family data for US Patent 10,598,101, here are the key technical details regarding its term and related applications as of May 14, 2026.

Patent Term and Expiration

• Projected Expiration Date: The projected expiration date for US Patent 10,598,101 is June 8, 2035. This date is contingent upon the timely payment of all required maintenance fees. The 4th-year maintenance fee was paid on September 6, 2023.
• Patent Term Adjustment (PTA): The patent has received a significant patent term adjustment. The standard 20-year patent term would expire on November 1, 2033, calculated from the earliest non-provisional filing date of its parent application (November 1, 2013). The adjusted expiration date of June 8, 2035, indicates a substantial PTA was granted by the USPTO to compensate for delays during the patent prosecution process.
• Patent Term Extension (PTE): There is no evidence of a Patent Term Extension (PTE) for this patent. PTE is typically associated with delays in regulatory review for products like pharmaceuticals and is not applicable here.

Application and Family Data

This patent is part of a large and active family of applications, indicating a strategic and ongoing effort by Champion Power Equipment Inc. to protect its dual-fuel technology.

• Continuation Applications: US Patent 10,598,101, which issued from application US 15/015,205, is itself a continuation and has spawned a series of subsequent continuation applications.

  • Parent Application: The '101 patent is a continuation of application US 14/069,747 (filed November 1, 2013), which issued as US Patent 9,435,273. This is the earliest-filed application from which the '101 patent claims priority.
  • Child (Continuation) Applications: A robust family of continuation applications has been filed, claiming priority back to the original 2013 application. This allows the assignee to pursue claims of varying scope and cover evolving technology. Key child applications include:
    • US 16/789,722 (filed Feb. 13, 2020), now US Patent 11,306,667
    • US 17/651,245 (filed Feb. 16, 2022), now US Patent 11,761,390
    • US 18/330,807 (filed June 7, 2023), now US Patent 11,905,896
    • US 18/443,530 (filed Feb. 16, 2024), now pending as publication US 2024/0183321 A1
    • US 19/027,054 (filed Jan. 17, 2025), now pending as publication US 2025/0154912 A1
    • US 19/027,095 (filed Jan. 17, 2025), now pending as publication US 2025/0163860 A1

• Divisional Applications: There are no divisional applications related to US Patent 10,598,101. The prosecution strategy appears to be focused exclusively on continuation applications.

• Foreign Family Members: The patent family also includes international counterparts, indicating an effort to secure patent rights in key foreign markets:

  • Canada: CA 2868722 C
  • China: CN 104533640 B

This information is based on the data available from the USPTO and public patent databases as of today's date.

Defensive Disclosure for U.S. Patent No. 10,598,101

Publication Date: May 14, 2026
Reference ID: DPD-10598101-A
Title: Derivative Embodiments and Cross-Domain Applications of Mechanically Interlocked Multi-Fuel Selector Assemblies

This document discloses novel variations, applications, and integrations of the core mechanism described in U.S. Patent No. 10,598,101. The intent is to place these concepts into the public domain to serve as prior art against future patent applications claiming these or obvious variants thereof. The disclosures herein are described to a level of detail sufficient for a person skilled in the art to practice the invention without undue experimentation.

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Derivatives of Independent Claim 1: Manual Selector for Dual Mechanical Valves

Claim 1 Core Concept: A manually operated selector switch on a valve assembly with two distinct mechanical valves to control flow from two fuel sources.

1. Material & Component Substitution

• Derivative 1.1: Ceramic Rotary Valves

  • Enabling Description: The first and second mechanical fuel valves are constructed as rotary shear valves using alumina ceramic (Al2O3) discs. The selector switch is mechanically linked to rotate these discs. One disc has inlet and outlet ports corresponding to the fuel lines. A second, spring-loaded disc rotates against the first. The rotation aligns or misaligns channels in the discs to open or close the fuel path. This provides superior wear resistance to abrasive particles in fuels and resilience to corrosive fuel additives like ethanol. The valve body is a carbon-fiber-reinforced PEEK (Polyether ether ketone) polymer for high strength and chemical inertness.

  • graph TD
        A[Fuel Source 1] --> V1{Ceramic Valve 1};
        B[Fuel Source 2] --> V2{Ceramic Valve 2};
        S[Selector Switch] --Mechanical Link--> V1;
        S --Mechanical Link--> V2;
        V1 --> E[Engine];
        V2 --> E;
        subgraph Valve Assembly
            V1;
            V2;
        end
    

• Derivative 1.2: Shape-Memory Alloy (SMA) Actuators

  • Enabling Description: The selector switch does not directly move the valve handles. Instead, it completes one of two low-voltage electrical circuits. Each circuit connects to a Nitinol (Nickel-Titanium alloy) wire actuator. When energized, the Nitinol wire heats, contracts, and pulls a lever to open its corresponding fuel valve (a standard ball valve). A bias spring closes the valve when the circuit is opened. The selector switch is a "break-before-make" design, ensuring that one circuit is de-energized before the other is energized, preventing simultaneous valve opening.

  • sequenceDiagram
        participant User
        participant SelectorSwitch
        participant SMA_Actuator1
        participant FuelValve1
        participant SMA_Actuator2
        participant FuelValve2
    
        User->>SelectorSwitch: Select Fuel 1
        SelectorSwitch->>SMA_Actuator1: Apply low voltage
        SMA_Actuator1->>FuelValve1: Contract and pull lever (Open)
        SelectorSwitch->>SMA_Actuator2: De-energize circuit
        SMA_Actuator2->>FuelValve2: Bias spring closes valve (Closed)
    

2. Operational Parameter Expansion

• Derivative 1.3: Cryogenic Dual-Fuel Selection

  • Enabling Description: The invention is scaled for cryogenic applications, specifically for a rocket engine selecting between liquid methane (LCH4) and liquid hydrogen (LH2). The valve assembly is constructed from Inconel 718 alloy to withstand temperatures down to -253°C. The mechanical valves are cryogenic-rated ball valves with extended bonnets to keep the manual selector switch handle at a safe operating temperature. The sealing elements are spring-energized PTFE seals. The selector switch has a high-torque gearbox to overcome potential ice formation and increased fluid viscosity at low temperatures.

  • flowchart LR
        subgraph Cryogenic Fuel System
            F1[LH2 Tank] --Insulated Line--> V1(Cryo Valve 1);
            F2[LCH4 Tank] --Insulated Line--> V2(Cryo Valve 2);
        end
        S[High-Torque Selector] ==> V1;
        S ==> V2;
        V1 --> E((Engine Combustion Chamber));
        V2 --> E;
    

• Derivative 1.4: Microfluidic Gas Selection

  • Enabling Description: The entire assembly is miniaturized onto a silicon-glass microfluidic chip for a gas chromatograph. The "fuel sources" are two different carrier gases (e.g., Helium and Nitrogen). The valves are micro-pneumatic membrane valves fabricated using photolithography and soft lithography (PDMS). The "selector switch" is a series of external pneumatic control lines. Applying pressure to one control line deflects a membrane to close one gas channel while a lack of pressure on the second line leaves its corresponding channel open, allowing for precise, low-volume gas selection.

  • graph TD
        subgraph Microfluidic Chip
            direction LR
            C1[Carrier Gas 1 In] --> M1{Membrane Valve 1};
            C2[Carrier Gas 2 In] --> M2{Membrane Valve 2};
            M1 --> O[GC Column];
            M2 --> O;
        end
        P1[Pneumatic Control 1] --Pressure--> M1;
        P2[Pneumatic Control 2] --Vent--> M2;
    

3. Cross-Domain Application

• Derivative 1.5: Aerospace - Redundant Hydraulic Systems

  • Enabling Description: In an aircraft flight control system, the "fuel sources" are two independent hydraulic systems (System A and System B). The "engine" is a flight control actuator for a rudder or aileron. The selector switch is a manual override lever in the cockpit or maintenance bay. It mechanically actuates two hydraulic shuttle valves. In the event of a failure in System A, the pilot or ground crew can manually slide the selector, which physically isolates the failed system and ensures the actuator is powered exclusively by System B, preventing hydraulic fluid mixing or pressure loss.

  • stateDiagram-v2
        [*] --> SystemA_Active
        SystemA_Active: Actuator powered by Hydraulic System A
        SystemB_Active: Actuator powered by Hydraulic System B
    
        SystemA_Active --> SystemB_Active: Manual Selector Moved (isolates A, engages B)
        SystemB_Active --> SystemA_Active: Manual Selector Moved (isolates B, engages A)
    

• Derivative 1.6: AgTech - Dual-Source Irrigation

  • Enabling Description: The "fuel sources" are a municipal water line and a rainwater collection tank. The "engine" is a field irrigation system. The selector switch is a large, durable lever on a valve manifold at the head of the field. It is mechanically linked to two 4-inch gate valves. A farmer can manually switch between using treated municipal water (e.g., during a drought) and free, untreated rainwater (when available), ensuring the irrigation system can only draw from one source at a time to prevent backflow and contamination of the municipal supply.

  • graph BT
        E[Irrigation Emitters] <-- M[Main Line];
        V1[Gate Valve 1] --> M;
        V2[Gate Valve 2] --> M;
        S[Selector Lever] --Linkage--> V1;
        S --Linkage--> V2;
        F1[Municipal Water] --> V1;
        F2[Rainwater Tank] --> V2;
    

4. Integration with Emerging Tech

• Derivative 1.7: IoT-Enabled Selector with Predictive Maintenance
  • Enabling Description: The manual selector switch is augmented with IoT sensors. A rotational position sensor (a simple potentiometer or Hall effect sensor) on each valve stem reports the open/closed status to a microcontroller (ESP32). An accelerometer on the selector switch detects when it is moved. The ESP32 transmits this data via LoRaWAN to a cloud platform. The platform uses an AI model to analyze the frequency of switching, time spent on each fuel, and correlates it with generator load data. It predicts when valve seals may require replacement and sends a maintenance alert. The manual override is preserved for safety.

  • sequenceDiagram
        participant Generator
        participant SelectorSwitch
        participant MCU
        participant LoRaWAN_Gateway
        participant Cloud_AI
    
        User->>SelectorSwitch: Manually switch fuel
        SelectorSwitch->>MCU: Transmit position change (via Hall sensor)
        MCU->>LoRaWAN_Gateway: Send data packet {Valve1:0, Valve2:1}
        LoRaWAN_Gateway->>Cloud_AI: Forward packet
        Cloud_AI->>Cloud_AI: Log event & run predictive model
        Cloud_AI-->>Maintenance_Portal: Alert: "Valve 2 approaching service interval"
    

5. The "Inverse" or Failure Mode

• Derivative 1.8: Failsafe Neutral-Position Selector
  • Enabling Description: The selector switch has three positions instead of two: "Fuel 1," "Fuel 2," and "OFF/SAFE." The OFF position is a detent in the center of travel. In this position, the mechanical linkage ensures both fuel valves are held securely in the closed position. This is the required position for transporting the generator. The linkage is designed with an over-center cam mechanism so that if the switch is jostled or not fully engaged in a fuel position, the springs in the cam will force it back to the central OFF position, preventing any fuel flow.

  • stateDiagram-v2
        [*] --> OFF
        OFF: Both valves closed
        Fuel1: Valve 1 open, Valve 2 closed
        Fuel2: Valve 2 open, Valve 1 closed
    
        OFF --> Fuel1: Slide Switch Left
        Fuel1 --> OFF: Slide Switch Center
    
        OFF --> Fuel2: Slide Switch Right
        Fuel2 --> OFF: Slide Switch Center
    
        Fuel1 --> Fuel2: Not Possible (must pass through OFF)
        Fuel2 --> Fuel1: Not Possible (must pass through OFF)
    

---

Derivatives of Independent Claim 17: Solenoid-Interlocked Selector

Claim 17 Core Concept: A selector switch with two fuel modes that also triggers a solenoid switch to open/close a fuel solenoid, working in concert with a mechanical valve assembly.

1. Material & Component Substitution

• Derivative 17.1: Latching Solenoid Valve System
  • Enabling Description: The fuel solenoid is replaced with a magnetic latching solenoid valve. This type of valve requires only a short electrical pulse to switch states (open or closed) and then remains in that state with no further power consumption, held in place by a permanent magnet. The selector switch, when moved, momentarily closes one of two circuits: one to send an "open" pulse, the other a "close" pulse. This dramatically reduces the standby power drain on the generator's battery, which is critical for devices with long periods of inactivity. The solenoid itself is constructed with a Kalrez® perfluoroelastomer seal for compatibility with a wide range of fuel chemistries.

  • flowchart TD
        subgraph Control
            SS[Selector Switch]
            P[Pulse Generator]
        end
        subgraph Fuel Line
            LSV[Latching Solenoid Valve]
        end
        SS --Position 1--> P --"Open" Pulse--> LSV;
        SS --Position 2--> P --"Close" Pulse--> LSV;
        LSV --Stays Open/Closed w/o Power--> ;
    

2. Operational Parameter Expansion

• Derivative 17.2: High-Pressure Gaseous Fuel Switching (300 Bar)
  • Enabling Description: This system is designed for switching between Compressed Natural Gas (CNG) and Hydrogen (H2) at pressures up to 300 bar. The solenoid valve is a high-pressure, pilot-operated design. The selector switch triggers a small, low-power solenoid (the pilot) which then uses the high-pressure gas itself to actuate the main valve piston, enabling control of the high-pressure flow with minimal electrical power. The valve body is 316L stainless steel, and all wetted components are compliant with hydrogen service requirements to prevent embrittlement.

  • graph LR
        S[Selector Switch] --> PS[Pilot Solenoid];
        F_HP_In[High-Pressure Fuel In] --> MV[Main Valve];
        F_HP_In --Pilot Line--> PS;
        PS --Control Pressure--> MV[Main Piston];
        MV --> F_HP_Out[Fuel to Engine];
    

3. Cross-Domain Application

• Derivative 17.3: Chemical Processing Plant - Reagent Selection
  • Enabling Description: In a batch chemical reactor, the "fuel sources" are two different liquid reagents (e.g., an acid and a base). The selector switch is on a control panel. When the process calls for the acid, the operator selects "Reagent A." This energizes a solenoid which opens the valve for the acid line. The selector switch also sends a signal to the plant's PLC (Programmable Logic Controller), which verifies via a flow meter that the acid is flowing before proceeding with the reaction. The electrical interlock via the solenoid prevents the accidental, simultaneous addition of incompatible reagents.

  • sequenceDiagram
        Operator->>SelectorPanel: Select Reagent A
        SelectorPanel->>Solenoid_A: Energize
        Solenoid_A->>Valve_A: Open
        SelectorPanel->>PLC: Signal Mode=Reagent_A
        Valve_A->>FlowMeter_A: Fluid Flow
        FlowMeter_A->>PLC: Report Flow Rate
        PLC->>PLC: Verify Flow_A > 0 AND Valve_B is closed
        PLC->>ProcessControl: Proceed with next step
    

4. Integration with Emerging Tech

• Derivative 17.4: Blockchain-Verified Fuel Source
  • Enabling Description: The system is integrated into a supply chain that requires provenance of fuel, such as sustainable biofuel. The selector switch's electrical contacts are wired to a cryptographic co-processor. When "Biofuel" mode is selected, the co-processor reads an NFC tag on the biofuel tank's coupling, which contains a signed hash of its batch data. The processor verifies the signature and writes a new transaction to a private blockchain, e.g., "Generator SN#123 consumed 1 liter from Biofuel Batch #XYZ at [Timestamp]." This creates an immutable log for carbon credit verification. The solenoid for the conventional fuel source is physically disabled until the blockchain transaction is confirmed.

  • graph TD
        A[Select Biofuel Mode] --> B{Read NFC Tag on Tank};
        B --> C{Verify Batch Signature};
        C --Valid--> D{Enable Biofuel Solenoid};
        C --Invalid--> E{Lockout; Alert User};
        D --> F{Log Consumption Event};
        F --> G((Write Transaction to Blockchain));
    

5. The "Inverse" or Failure Mode

• Derivative 17.5: De-energize-to-Close Purge System
  • Enabling Description: The primary function is to ensure a safe shutdown. The fuel solenoid is a "normally open" valve that is held closed by continuous power when the generator is running. When the user moves the selector switch to "OFF," or if the generator loses battery power, the solenoid de-energizes and the valve springs open. This valve doesn't feed fuel to the engine, but rather opens a line to an inert gas (e.g., Nitrogen) purge system. This action flushes any remaining flammable fuel vapor from the lines and carburetor before a long-term shutdown, reducing the risk of fire or gum deposits.

  • stateDiagram-v2
        state "Running" as Running
        state "Purging" as Purging
        state "OFF" as Off
    
        [*] --> Off
        Off --> Running: Start Generator & Select Fuel
        Running --> Purging: Select "OFF" or Power Loss
        Purging --> Off: Purge Cycle Complete
    
        state Running {
            direction LR
            PurgeSolenoid: Energized (Closed)
            FuelSolenoid: Energized (Open)
        }
        state Purging {
            direction LR
            PurgeSolenoid: De-energized (Open)
            FuelSolenoid: De-energized (Closed)
        }
    

---

Combination Prior Art Scenarios

1. Combination with Modbus Protocol:

   • Scenario: The fuel selector switch (as in Derivative 1.7 with IoT sensors) is integrated into an industrial generator that uses the Modbus RTU open-source protocol for communication over an RS-485 serial line. The microcontroller acts as a Modbus slave device.
   • Enabling Description: The microcontroller's firmware includes a Modbus slave library. It maps the status of the two fuel valves (open/closed) and the solenoid to discrete input registers (Coils). A master controller (like a SCADA system) can poll the generator's selector switch for its status (Register 0x01 for Fuel 1, 0x02 for Fuel 2). This allows for remote monitoring and data logging of fuel selection within standard industrial control systems, making the manual switch part of a larger automated system. This combination is obvious to anyone skilled in industrial automation.

2. Combination with MQTT Protocol for IoT Fleets:

   • Scenario: A fleet of portable dual-fuel generators, each equipped with the IoT-enabled selector (Derivative 1.7), uses the open-source MQTT (Message Queuing Telemetry Transport) protocol to report their status.
   • Enabling Description: The ESP32 microcontroller on each selector switch acts as an MQTT client. Upon a change in the selector's state, it publishes a JSON payload to a specific topic on a central MQTT broker. For example, telemetry/generator/SN123/fuel_status with payload {"selected_fuel": "LPG", "timestamp": "2026-05-14T10:00:00Z"}. A dashboard subscribed to the telemetry/generator/+/fuel_status wildcard topic can monitor the entire fleet's fuel usage in real-time. This is a standard architecture for managing fleets of IoT devices.

3. Combination with Controller Area Network (CAN Bus) Standard:

   • Scenario: The fuel selector switch (as in Derivative 17.2 or 1.5) is installed on a vehicle or heavy equipment that uses the CAN bus protocol (ISO 11898) for internal communication.
   • Enabling Description: The selector switch is connected to a CAN controller. When the switch position changes, the controller broadcasts a standard CAN frame onto the bus. The frame would have a specific identifier (e.g., 0x1F0 for "Fuel System Status") and a data payload indicating the selected fuel (e.g., 0x01 for gasoline, 0x02 for LPG). The Engine Control Unit (ECU) on the same CAN bus receives this message and adjusts engine parameters (ignition timing, fuel trim) for the selected fuel. This makes the mechanical switch a seamless electronic component in modern vehicle architecture.