PTAB

IPR2025-01121

Harbor Freight Tools USA Inc v. Champion Power Equipment Inc

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Fuel System for a Multi-Fuel Internal Combustion Engine
  • Brief Description: The ’120 patent discloses a fuel system for multi-fuel engines, such as those in generators, that operate on both liquid (e.g., gasoline) and gaseous (e.g., LPG) fuels. The system uses a switch-controlled arrangement of cutoff solenoids and timing circuits to manage fuel flow and enable smooth on-the-fly switching between fuel sources while preventing unstable operating conditions.

3. Grounds for Unpatentability

Ground 1: Claims 1-2, 4-6, and 9-10 are anticipated by, or alternatively obvious over, Imamura

  • Prior Art Relied Upon: Imamura (JPH1182083A).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Imamura disclosed every element of independent claim 1. Imamura taught a dual-fuel (gasoline and LPG) engine with a carburetor, a liquid cutoff solenoid (18) controlling a gasoline valve (17), a gaseous cutoff solenoid (14) controlling an LPG valve (13), a switch (2) to select the fuel, and timing circuits (T1, T2) electrically coupled to the solenoids. These timing circuits controlled the actuation of the solenoids to create a slight overlap in fuel delivery when switching, preventing the engine from stalling.
    • Motivation to Combine (for §103 grounds): The alternative obviousness argument relied on the same teachings, asserting that even if not explicitly disclosed, a POSITA would have found it obvious to apply Imamura’s disclosed timing principles to achieve the claimed functions.
    • Expectation of Success (for §103 grounds): A POSITA would have expected success as Imamura explicitly taught using timer elements to control solenoid actuation for the purpose of smooth fuel transition.

Ground 2: Claims 12-15 and 17-19 are anticipated by The Workshop Manual

  • Prior Art Relied Upon: Kubota DF972-E2 Workshop Manual (“Workshop Manual”).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted the Workshop Manual, which described the Kubota DF972-E2 dual-fuel engine, anticipated the claims. For independent claim 12, the manual disclosed a multi-fuel (gasoline/LPG) generator system, including an engine with an alternator. For independent claim 18, it described a carburetor with a throat, float bowl, choke/throttle valves, and main and idle fuel circuits. The system used a "Fuel Select Switch" to operate gasoline and LPG cutoff solenoids, allowing on-the-fly switching (as confirmed by the related Operator’s Manual) while preventing simultaneous fuel delivery. The manual also disclosed a dual-stage vaporizer that functioned as the claimed primary and secondary pressure regulators.

Ground 3: Claims 12-17 are obvious over Nakafushi in view of Jungmann and Parlatore

  • Prior Art Relied Upon: Nakafushi (JPS61283734A), Jungmann (Application # 2014/0239645), and Parlatore (Application # 2011/0100335).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that Nakafushi taught the base multi-fuel (gasoline/LPG) engine with a carburetor, liquid and gaseous fuel lines, and a switch-controlled valve system to prevent simultaneous fuel flow. Jungmann supplied the teaching of using such a multi-fuel engine with an alternator to create a generator. Parlatore taught an off-board, dual-stage fuel regulator system for gaseous fuels, comprising primary and secondary regulators located near the fuel tank.
    • Motivation to Combine (for §103 grounds): A POSITA would combine Nakafushi and Jungmann to create a versatile multi-fuel generator, a well-known application. A POSITA would further incorporate Parlatore's off-board regulator system to enhance safety (by lowering pressure in the fuel line running to the engine) and convenience (by allowing for larger, easily swappable fuel tanks), which were known benefits.
    • Expectation of Success (for §103 grounds): Success was expected because the combination involved applying known components for their intended purposes: using a multi-fuel engine in a generator and adding a standard, safety-enhancing off-board regulator system.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including:

    • Claim 3 over Imamura in view of French and/or Frantz (adding a rheostat to a timing circuit).
    • Claims 7-8 over Imamura in view of Olmr (adding a second liquid cutoff solenoid within the carburetor float bowl).
    • Claim 11 over Imamura in view of Jungmann and Parlatore (creating a generator with an off-board regulator system).
    • Claim 16 over the Workshop Manual in view of Parlatore (adding an off-board pressurized fuel container).
    • Claims 18-19 over Nakafushi in view of Kirk and Olmr (adding a standard idle fuel circuit and specifying a control valve as a solenoid).

4. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-19 of the ’120 patent as unpatentable.