PTAB

IPR2025-01228

Generac Power Systems Inc v. Champion Power Equipment Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Fuel Selector for Dual Fuel Generator
  • Brief Description: The ’896 patent discloses a fuel selector for a dual fuel generator that uses a sliding panel, termed a "selector switch," to interlock a pair of fuel valve handles. This mechanical interlock is designed to prevent a user from opening both fuel valves simultaneously, thereby preventing the mixing of different fuels.

3. Grounds for Unpatentability

Ground 1: Claims 1-38 are obvious over DuroMax and DeVries in view of Nakafushi and Olmr

  • Prior Art Relied Upon: DuroMax (Duro Max XP4400EH Operator’s Manual), DeVries (Patent 7,481,087), Nakafushi (JPS61283734A), and Olmr (Patent 5,301,644).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that DuroMax, a prior art dual-fuel (LPG/gasoline) generator, discloses all basic features of the claimed generator but lacks a safety interlock, presenting the exact problem the ’896 patent purports to solve. DeVries teaches a key-based safety interlock system for industrial appliances with two valves, where a single key ensures only one valve can be operated at a time. This system directly maps to the claimed "selector switch" and "valve assembly." The combination is further modified with Nakafushi and Olmr, which teach using a carburetor shutoff solenoid to prevent residual gasoline from entering the engine when running on LPG. This addresses a known performance and safety issue in carbureted dual-fuel engines like DuroMax.
    • Motivation to Combine: A POSITA would combine the DeVries safety interlock with the DuroMax generator to solve the recognized and dangerous problem of simultaneous fuel flow. The motivation to add the Nakafushi/Olmr solenoid is similarly strong: to prevent unsteady performance, carbon monoxide poisoning, and backfires caused by leftover gasoline in the carburetor—a well-known issue when switching from gasoline to LPG.
    • Expectation of Success: Petitioner asserted a high expectation of success, as combining a known safety interlock (DeVries) with a standard generator (DuroMax) is a straightforward application of known principles. Similarly, adding a common carburetor solenoid (Olmr) to solve a known fuel-switching problem (identified in Nakafushi) would be a predictable modification.

Ground 2: Claims 7-11, 15-20, and 30-35 are anticipated by Fujisawa

  • Prior Art Relied Upon: Fujisawa (JP2005330867).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground was argued in the alternative, adopting the Patent Owner’s apparent claim construction from related litigation where a single component (a dial) is considered to be both the "selector switch" and the "valve handle." Under this construction, Petitioner argued Fujisawa anticipates the claims. Fujisawa discloses a dual-fuel power generator with a single rotary knob (60) and integrated cam body (59) that directly actuates two fuel valves. Petitioner asserted that this single rotary knob mechanism meets the limitations of the claimed "selector switch" under the Patent Owner's broad interpretation. The cam followers (57a, 57b) that actuate the valves function as the "valve handles."
    • Key Aspects: This argument hinges entirely on adopting the Patent Owner’s alleged litigation construction, which Petitioner contended is incorrect but demonstrates invalidity even if accepted.

Ground 3: Claims 1-5 and 7-38 are obvious over Fujisawa and DuroMax in view of Nakafushi and Olmr

  • Prior Art Relied Upon: Fujisawa (JP2005330867), DuroMax (Duro Max XP4400EH Operator’s Manual), Nakafushi (JPS61283734A), and Olmr (Patent 5,301,644).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground starts with Fujisawa's dual-fuel generator, which uses two types of LPG (propane and butane). Petitioner argued it would have been obvious to modify Fujisawa to use the more common and efficient fuel combination of LPG and gasoline, as taught by DuroMax. This modification would introduce the known problem of residual gasoline remaining in the carburetor when switching to LPG. To solve this, a POSITA would have been motivated to incorporate the carburetor shutoff solenoid taught by Nakafushi and Olmr.
    • Motivation to Combine: The primary motivation was to improve Fujisawa’s design by using more advantageous and widely available fuels (gasoline instead of butane). This modification would create a well-understood problem (residual gasoline in the carburetor) with a well-known solution (a solenoid shutoff), providing the motivation to further incorporate Nakafushi and Olmr.
    • Expectation of Success: Success would be highly predictable, as configuring engines to run on gasoline and LPG was routine, and using a solenoid to control fuel flow in a carburetor was a standard and reliable technique.

  • Additional Grounds: Petitioner asserted additional obviousness challenges based on DuroMax/DeVries and Fujisawa/DuroMax combinations that relied on similar reasoning.

4. Key Claim Construction Positions

  • Petitioner argued that based on the specification and prosecution history of the parent ’101 patent, two terms required constructions that were dispositive to the invalidity analysis.
    • "Selector Switch": Petitioner proposed this term be construed as "a movable component whose positioning enables subsequent user selection of only one fuel source." This construction emphasizes the two-step, indirect nature of the claimed interlock (i.e., sliding a cover to provide access to a separate valve handle), distinguishing it from a single control that directly selects the fuel.
    • "Valve Assembly": Petitioner proposed this term be construed as "having at least one fuel valve and corresponding valve handle" and "being a separate structure from the selector switch." This construction was based on arguments the applicant made to overcome prior art during prosecution, establishing that the interlock mechanism ("selector switch") and the actuation mechanism ("valve assembly") are physically distinct components.

5. Relief Requested

  • Petitioner requests institution of IPR and cancellation of claims 1-38 as unpatentable.