Ford Motor Company v. Paice LLC

1. Case Identification

• Case #: IPR2014-00875
• Patent #: 7,559,388
• Filed: June 5, 2014
• Petitioner(s): Ford Motor Company
• Patent Owner(s): PAICE LLC
• Challenged Claims: 1-4, 6, 12, and 19

2. Patent Overview

• Title: Hybrid Vehicle
• Brief Description: The ’388 patent discloses a hybrid electric vehicle (HEV) with a series-parallel architecture, including an internal combustion engine, two AC electric motors, and AC-DC converters. The system is controlled by a microprocessor to improve fuel economy by operating the engine primarily in its most efficient range and using the electric motors to supplement torque during transient load conditions.

3. Grounds for Unpatentability

Ground 1: Claims 1, 3, and 19 are obvious over Ehsani and Vittone

• Prior Art Relied Upon: Ehsani (Patent 5,586,613) and Vittone (a 1994 International Electric Vehicle Symposium paper).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Ehsani discloses a series-parallel HEV architecture (Fig. 5) that meets nearly all limitations of independent claims 1 and 19. This includes two AC electric machines (a motor and a generator with dual functionality), two corresponding AC-DC converters, an electrical storage device (battery), and a controller. The final limitation of the independent claims—a specific control strategy where the motor supplements power when the rate of change of road load exceeds a threshold rate of change for the engine's torque output—is allegedly disclosed by Vittone. Vittone’s Fig. 8 illustrates a "steady state" engine management strategy where the engine torque change is limited (the threshold), and the electric motor provides the remaining required torque to meet transient driver demand (the road load).
  • Motivation to Combine: A person of ordinary skill in the art (POSA) would combine Vittone’s control strategy with Ehsani’s HEV architecture to solve the known problem of engine transients. Both references are directed at improving fuel efficiency and reducing emissions in parallel HEVs. A POSA would have been motivated to implement Vittone’s strategy, which provides a "further contribution to the emission reduction," into the hybrid system of Ehsani to achieve the predictable result of optimized fuel economy.
  • Expectation of Success: A POSA would have had a reasonable expectation of success because implementing Vittone's control strategy is a modification of control algorithms that requires no significant change to the underlying HEV hardware architecture disclosed in Ehsani.
  • Key Aspects: Petitioner contended that dependent claim 3, which adds varying the threshold value based on the battery's state of charge, is also obvious because Vittone teaches selecting operating modes based on battery charge, making it a routine optimization for a POSA.

Ground 2: Claims 1, 3, 4, and 19 are obvious over Kawakatsu and Vittone

• Prior Art Relied Upon: Kawakatsu (Patent 4,335,429) and Vittone (a 1994 International Electric Vehicle Symposium paper).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner asserted that Kawakatsu discloses a two-motor parallel HEV with detailed operating modes where the engine operates only under high-efficiency conditions. Kawakatsu teaches the core vehicle architecture with two motor/generators, a controller, and a battery. However, Kawakatsu discloses a DC motor system. Petitioner argued that Vittone teaches the benefits of using an AC motor system. The combination of Kawakatsu's architecture and operating modes with Vittone's AC motor and "steady state" engine control strategy (as described in Ground 1) allegedly renders the claims obvious.
  • Motivation to Combine: A POSA in 1998 would have been motivated to modify Kawakatsu’s DC-based system with Vittone’s AC motor technology to gain its known benefits, such as improved torque response and efficiency. It would have been a simple substitution to add AC-DC converters (inverters), as taught by Vittone, to integrate the AC motors with the DC battery. The motivation to add Vittone’s control strategy is the same as in Ground 1: optimizing fuel economy and reducing emissions.
  • Expectation of Success: Success would be expected as substituting DC motors for AC motors and adding the necessary inverters was well within the capability of a POSA at the time.
  • Key Aspects: This combination was used to challenge claim 4, which requires the maximum torque from the electric motor(s) to be larger than the maximum torque from the engine. Petitioner argued Kawakatsu’s operating charts (Fig. 2) explicitly show operating regions where the motor-only torque exceeds the maximum engine-only torque.

• Additional Grounds: Petitioner asserted additional obviousness challenges against dependent claims by adding further references to the Ehsani and Vittone combination. These included:

  • Adding Caraceni (a 1998 SAE Technical Paper) to challenge claim 2, arguing Caraceni teaches refining Vittone's threshold value to be "no more than about 2% per revolution."
  • Adding Fjallstrom (Patent 5,120,282) to challenge claim 6, arguing Fjallstrom teaches adding a third electric motor to a second pair of wheels to create an all-wheel-drive (AWD) HEV.
  • Adding Yamaguchi (Patent 5,865,263) to challenge claim 12, arguing Yamaguchi teaches the known technique of preheating an engine before starting to improve driveability and reduce cold-start emissions.

4. Key Claim Construction Positions

• The petition argued for a specific construction of the term "road load", which appears in all challenged claims.
• For the purposes of the IPR proceeding, Petitioner proposed construing "road load" as "the instantaneous torque required for propulsion of the vehicle, which may be positive or negative in value." This construction was based on positions taken by the Patent Owner in prior district court litigations involving the same patent family. Petitioner reserved the right to argue for a narrower construction in any concurrent district court case.

5. Key Technical Contentions (Beyond Claim Construction)

• A central technical argument was the "dual functionality" of the electric machines in the prior art. Petitioner contended that even when a reference labeled one machine as a "generator" and another as a "motor" (as in Ehsani's Fig. 5), a POSA would understand that such AC machines inherently possess dual functionality. This means the "motor" can perform regenerative braking (generate power) and the "generator" can act as a motor (e.g., to start the engine), which was critical for mapping the prior art to claim limitations requiring bidirectional power flow and conversion.

6. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claims 1-4, 6, 12, and 19 of Patent 7,559,388 as unpatentable under 35 U.S.C. §103.