General Electric Co v. United Technologies CORoration

1. Case Identification

• Case #: IPR2016-00534
• Patent #: 8,365,513
• Filed: January 29, 2016
• Petitioner(s): General Electric Company
• Patent Owner(s): United Technologies Corporation
• Challenged Claims: 1-8

2. Patent Overview

• Title: Turbofan Engine with Variable Area Bypass Nozzle Control
• Brief Description: The ’513 patent discloses a turbofan engine featuring a variable area bypass nozzle. The system uses a controller to adjust the nozzle's exit area to achieve a target fan operability line, balancing engine efficiency and stall margin across different operating conditions like idle, takeoff, and cruise.

3. Grounds for Unpatentability

Ground 1: Anticipation - Claims 1, 2, and 4-8 are anticipated by Willis under 35 U.S.C. § 102.

• Prior Art Relied Upon: Willis (William S. Willis, Quiet Clean Short-Haul Experimental Engine (QCSEE) Final Report, 1979).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Willis, a NASA final report on an advanced turbofan engine program, disclosed every limitation of the challenged claims. The Willis engine included a spool supporting a turbine within a core nacelle, a turbofan coupled to the spool, and a fan nacelle creating a bypass flow path. Willis explicitly described using a digital controller to command a variable area fan nozzle (the "flow control device") to achieve different target operating lines for takeoff and cruise. The controller varied the nozzle area based on the power lever (throttle) setting, featured effectively open and closed conditions corresponding to different nozzle exit areas, and specified that the nozzle was in its maximum area (effectively open) position during low-power ground idle conditions.
  • Key Aspects: Petitioner contended Willis also anticipated dependent claims by disclosing target operating lines near the stall boundary (claim 2), a throttle position sensor (claim 4), physically open and closed nozzle areas (claim 5), nozzle flaps moved by actuators (claim 6), throttling of bypass flow in the closed condition (claim 7), and a closed condition corresponding to cruise (claim 8).

Ground 2: Obviousness - Claim 6 is obvious over Willis in view of Gisslen.

• Prior Art Relied Upon: Willis (QCSEE Final Report, 1979) and Gisslen (Patent 3,892,358).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground addressed claim 6’s specific requirement for "an actuator adapted to move a flap." Petitioner argued that while Willis disclosed a complete system with a variable nozzle and a digital control commanding it, Gisslen explicitly detailed a common implementation. Gisslen taught a variable area exhaust nozzle for a turbofan engine that comprises an annular array of flaps moved between open and closed positions by an "actuator means."
  • Motivation to Combine: A POSITA would combine these references because they addressed the same technology (variable nozzles for turbofan engines) and originated from the same entity (General Electric) in the same era. Gisslen’s disclosure of an actuator moving flaps represented a standard, well-known, and predictable method for implementing the variable nozzle function described in the Willis engine system.
  • Expectation of Success: A POSITA would have a high expectation of success, as this combination merely involved applying a conventional mechanical actuation method (from Gisslen) to the specific engine control system (of Willis).

Ground 3: Obviousness - Claim 3 is obvious over Willis in view of Harner.

• Prior Art Relied Upon: Willis (QCSEE Final Report, 1979) and Harner (Patent 3,932,058).

• Core Argument for this Ground:

  • Prior Art Mapping: This ground focused on claim 3, which required an "airspeed sensor in communication with the controller." Willis’s control system used throttle position as an input. Harner disclosed a control system for a similar turbofan engine that used flight Mach number (a measure of airspeed) in addition to throttle position to control the fan nozzle area. Harner’s system used the airspeed input specifically to prevent fan surge and improve stability.
  • Motivation to Combine: A POSITA would be motivated to incorporate Harner’s airspeed-based control into the Willis engine. The low-pressure-ratio fans described in Willis were known to be susceptible to instability. A POSITA would naturally look to known solutions, like Harner's use of airspeed data, to enhance fan stability when adapting the Willis test-cell engine for use on an actual aircraft. Because the Willis engine was tested in a static test cell (zero airspeed), it had no need for an airspeed sensor, but adding one for flight applications would be a logical and obvious modification.
  • Expectation of Success: Success would be expected, as it involved integrating a known control parameter (airspeed) from Harner into the Willis control system to achieve the predictable benefit of improved fan stability.

• Additional Grounds: Petitioner also asserted that claims 2 and 7 are obvious over Willis in view of the general knowledge of a POSITA. This argument contended that the functional outcomes recited in these claims—operating near a stall boundary for efficiency (claim 2) and throttling flow with a smaller nozzle exit (claim 7)—were the inherent and well-understood results of implementing the variable nozzle system taught by Willis.

4. Key Claim Construction Positions

• "flow control device": Petitioner argued this term should be construed as any structure or device that effectively changes the nozzle exit area of the bypass flow path. This construction was supported by the specification and encompassed the "variable area fan nozzle" commonly known in the art and described in the prior art references.
• "effectively open condition corresponds to an engine idle condition": Petitioner asserted this phrase means the nozzle exit area is in its larger configuration during engine idle. This limitation was added during prosecution to overcome a rejection over Harner. Petitioner argued Willis explicitly disclosed this feature, showing the fan nozzle scheduled to its maximum area at low power settings corresponding to ground idle.
• "throttle" (Claim 7): In the context of the claim, Petitioner argued that a POSITA would understand "throttle" to simply mean "reduce," as in reducing the flow through the bypass path when the nozzle is in the "effectively closed condition."

5. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claims 1-8 of Patent 8,365,513 as unpatentable.