PTAB

IPR2025-00951

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

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1. Case Identification

2. Patent Overview

  • Title: Fuel Selector for Dual Fuel Generator
  • Brief Description: The ’101 patent discloses a fuel selector for a dual-fuel (e.g., LPG and gasoline) generator. The system uses a "selector switch," described as a sliding panel, that mechanically interlocks with two separate fuel valve handles to prevent both from being in the "ON" position simultaneously, thereby avoiding the unsafe mixing of fuels.

3. Grounds for Unpatentability

Ground 1: Obviousness over DuroMax in view of De Vries - Claims 1-5, 8-16, and 18-19 are obvious over DuroMax in view of De Vries.

  • Prior Art Relied Upon: DuroMax (XP4400EH Operator’s Manual), De Vries (Patent 7,481,087).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that DuroMax discloses a conventional dual-fuel generator with separate, independently operated valves for LPG and gasoline. The ’101 patent itself allegedly admits that such a configuration is typical prior art and presents a safety risk because both valves can be opened at once. De Vries was argued to disclose a valve assembly with a "safety interlock system" (a key-based lock) specifically designed to ensure a correct, predetermined sequence of valve operation and prevent hazardous situations by allowing only one valve to be open at a time.
    • Motivation to Combine: A person of ordinary skill in the art (POSITA) would be motivated to address the known safety issue of simultaneous fuel flow in the DuroMax generator. Petitioner asserted that De Vries explicitly teaches its interlock system can be supplied independently to solve safety problems in industrial appliances. A POSITA would therefore combine the De Vries safety interlock with the DuroMax generator's valve system to create a safer product.
    • Expectation of Success: A POSITA would have a reasonable expectation of success, as De Vries teaches its interlock system is suitable for controlling the flow of liquid or gaseous fluids in industrial appliances, which would include a dual-fuel generator like DuroMax. The components were argued to be standard and their integration straightforward.

Ground 2: Obviousness over DuroMax and De Vries in view of Nakafushi and Olmr - Claims 1-19 are obvious over DuroMax, De Vries, Nakafushi, and Olmr.

  • Prior Art Relied Upon: DuroMax, De Vries, Nakafushi (JPS61283734A), and Olmr (Patent 5,301,644).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground builds upon Ground 1 to address limitations related to a carburetor solenoid switch (claims 6-7, 17). Petitioner argued that a POSITA, having combined DuroMax and De Vries, would recognize another problem: residual gasoline in the carburetor mixing with LPG, causing an over-rich fuel ratio and unsteady performance. Nakafushi was argued to identify this exact problem and solve it by adding a control valve downstream of the carburetor's float bowl, linked to the fuel selection mechanism. Olmr was presented as teaching the specific implementation of this control valve as a solenoid valve, a common component for this purpose.
    • Motivation to Combine: A POSITA would be motivated to solve the well-known problems of engine backfire and unsteady performance caused by residual fuel. Petitioner asserted a POSITA would look to solutions like Nakafushi, which addresses the precise issue. To implement Nakafushi's control valve, a POSITA would use a well-known solenoid valve, as taught by Olmr, and couple its activation to the selector mechanism of De Vries to automate the process.
    • Expectation of Success: Success would be expected because the combination addresses known, predictable problems using well-understood components. De Vries itself discloses coupling its interlock to an electric switch, providing a clear path to integrate the solenoid taught by Nakafushi and Olmr.

Ground 3: Anticipation by Fujisawa - Claims 1-4, 9-14, and 18-19 are anticipated by Fujisawa.

  • Prior Art Relied Upon: Fujisawa (JP2005330867).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground was presented as an alternative argument, proceeding under the Patent Owner's apparent claim construction from related litigation. Petitioner contended that under this alternative construction, Fujisawa anticipates the challenged claims. Fujisawa discloses a dual-fuel generator with a single rotary knob (60) that operates a cam body (59). The cam, in turn, actuates two separate valve bodies (55a, 55b) to ensure only one fuel (propane or butane) flows at a time. Petitioner argued that under the Patent Owner's allegedly broader construction, Fujisawa's rotary knob/cam assembly (60, 59) meets the definition of the "selector switch," and the cam followers (57a, 57b) or the entire mechanism could be considered the "valve assembly" with "valve handles," thus anticipating all limitations of the independent claims.
    • Key Aspects: This argument hinges entirely on adopting a claim construction that Petitioner argued is incorrect and contradicts the prosecution history, but which Petitioner asserted the Patent Owner relies on for infringement. Under this alternative view, the integrated knob-cam-valve mechanism of Fujisawa reads directly on the claim elements.

  • Additional Grounds: Petitioner asserted additional obviousness challenges over Fujisawa in view of DuroMax (Ground 4) and over Fujisawa and DuroMax in view of Nakafushi and Olmr (Ground 5). These grounds argued that it would have been obvious to modify Fujisawa to use gasoline instead of butane (as taught by DuroMax) and to add a carburetor solenoid (as taught by Nakafushi/Olmr) for the same reasons of safety and performance improvement outlined in Grounds 1 and 2.

4. Key Claim Construction Positions

  • "Selector Switch": Petitioner argued that based on the patent's specification and prosecution history, this term should be construed as "a movable component whose positioning enables subsequent user selection of only one fuel source." The key distinction is that the switch itself does not select the fuel but is a separate component (a sliding plate) that physically blocks one valve handle to enable a user to then operate the other. This construction was argued to be necessary to distinguish prior art like Poehlman, where the selector and valve were not separate structures.
  • "Valve Assembly": Petitioner argued this term must be construed as a structure that is "separate and distinct from the selector switch" and "comprises at least one fuel valve and a corresponding valve handle." This was based on arguments made during prosecution to overcome rejections, where the applicant allegedly distinguished prior art by emphasizing the presence of manual valve handles as part of the valve assembly, separate from the selector switch.
  • Patent Owner's Apparent Construction: Petitioner contended that in related litigation, the Patent Owner adopted a conflicting construction where a single dial/knob can be both the "selector switch" and the "valve handle" component of the "valve assembly." The anticipation argument in Ground 3 relies on this alternative construction.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-19 of Patent 10,598,101 as unpatentable under 35 U.S.C. §102 and §103.