PTAB

IPR2020-00405

General Electric Co v. United Technologies Corp

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Key Events
Petition

1. Case Identification

2. Patent Overview

  • Title: Variable Property Acoustic Liner
  • Brief Description: The ’548 patent discloses a variable property acoustic liner for noise suppression in aircraft gas turbine engines. The technology involves an acoustic liner with a cellular core, comprising resonating chambers, sandwiched between a perforated face sheet and a base plate, where geometric properties of the liner segments are varied to attenuate different noise frequencies.

3. Grounds for Unpatentability

Ground 1: Claims 1-9 and 20-28 are obvious over Heldenbrand in view of Kisner

  • Prior Art Relied Upon: Heldenbrand (NASA Report CR-159758, 1979) and Kisner (NASA Conference Publication 2126, 1980).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Heldenbrand (the final report) and Kisner (a sub-report on acoustics) both describe the same AiResearch QCGAT geared turbofan engine, developed for a NASA program to create quieter engines. The combination allegedly disclosed a geared turbofan engine with a nacelle, fan casing, and core casing defining a bypass flow duct. Critically, these references were asserted to teach the use of a plurality of discrete, spaced-apart acoustic liner segments with varied geometric properties to attenuate a broad spectrum of noise frequencies. Petitioner mapped specific disclosures in Kisner to show variations in resonator chamber width (honeycomb cell size) and in Heldenbrand to show variations in core depth and face sheet porosity (percent open area) between different liner segments.
    • Motivation to Combine: A POSITA would combine Heldenbrand and Kisner because they document the same QCGAT engine program. Petitioner noted that Heldenbrand, as the primary report, explicitly acknowledged Kisner’s technical contributions to the program's acoustics work. Therefore, a POSITA seeking a complete understanding of the engine's acoustic design would be motivated to consult Kisner's more detailed acoustic analysis to supplement the information in Heldenbrand.
    • Expectation of Success: Petitioner asserted a high expectation of success, as the acoustic treatments detailed in Kisner were specifically designed for and tested on the QCGAT engine described in Heldenbrand. There would be no technical barriers to combining teachings intended for the same product.

Ground 2: Claims 11-19 and 30-36 are obvious over QCSEE-1 in view of QCSEE-2

  • Prior Art Relied Upon: QCSEE-1 (NASA Report CR-159473, 1979) and QCSEE-2 (NASA Report CR-135008, 1976).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that QCSEE-1 (the final report) and QCSEE-2 (a sub-report on nacelle and nozzle design) describe GE's "Quiet, Clean Short-haul Experimental Engine" (QCSEE) program. This combination was argued to disclose a geared turbofan engine with an acoustic liner comprised of multiple "zones" with different geometric properties, tuned to attenuate different frequency ranges. Specifically, Petitioner pointed to figures in QCSEE-2 showing that different acoustic liner zones in the bypass flow duct had different face sheet thicknesses, a key limitation of independent claims 11 and 30. The combination was also asserted to teach a low-pressure spool with a low-pressure turbine, with Petitioner arguing that the motivation to add a low-pressure compressor was established by issue preclusion from a prior IPR (IPR2017-00425).
    • Motivation to Combine: A POSITA would combine the QCSEE reports because they describe the same engine. QCSEE-1, the final report, explicitly cited QCSEE-2 as a "Related Report," directly guiding a researcher to review it for more detailed information on specific design aspects. The reports are complementary, with QCSEE-2 providing detailed design data for the nacelle and acoustic liners summarized in QCSEE-1.
    • Expectation of Success: Petitioner argued a POSITA would have a high expectation of success in combining the disclosures. The information is complementary and concerns the same integrated engine system, ensuring compatibility between the components and acoustic treatments described in each report.
  • Additional Grounds: Petitioner asserted that claims 10 and 29 are obvious by adding Morin (Patent 7,540,354) to the Heldenbrand/Kisner combination to teach the use of micro-perforated face sheets. Petitioner also challenged claims 17 and 34 by adding Mani (Patent 3,937,590) to the QCSEE-1/QCSEE-2 combination to teach circumferential segmentation of acoustic liners, if the claims are interpreted to require it.

4. Key Claim Construction Positions

  • "bypass flow duct": Petitioner argued this term is not limited to the area aft of the fan, but encompasses the entire duct defined by the fan casing and nacelle in which the fan is disposed. This construction is based on the plain language of claim 1 ("a bypass flow duct in which the fan is disposed") and figures in the ’548 patent showing the duct and associated liner segments extending forward of the fan. This broader construction was central to applying prior art showing acoustic treatment in the engine inlet to the claimed invention.

5. Relief Requested

  • Petitioner requested that the Board institute a trial based on the stated grounds and cancel claims 1-36 of 10,066,548.