Ford Motor Co 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 Control System
• Brief Description: The ’388 patent describes a hybrid electric vehicle (HEV) architecture comprising an internal combustion engine, multiple electric motors, and a battery bank. The invention is directed to a microprocessor-based control strategy that operates the engine primarily within its most efficient range to improve fuel economy.

3. Grounds for Unpatentability

Ground 1: Obviousness over Ehsani and Vittone - Claims 1, 3, and 19 are obvious over Ehsani in view of Vittone.

• Prior Art Relied Upon: Ehsani (Patent 5,586,613) and Vittone (a 1994 FIAT symposium paper).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Ehsani disclosed the core architecture of a series-parallel HEV claimed in independent claims 1 and 19. This included two AC electric motors (one acting as a generator), an engine coupled to the second motor, separate AC/DC converters for each motor, an electrical storage device (battery), and a controller. Petitioner asserted that the only missing element was the specific control strategy, which was supplied by Vittone. Vittone allegedly taught the claimed control method wherein the rate of change of the engine’s torque output is limited to a threshold value, and when the rate of change of road load exceeds this threshold, the electric motor supplies the remaining required torque to handle the transient demand. For claim 3, Vittone was cited for teaching that the controller varies this threshold based on the battery's state of charge.
  • Motivation to Combine: Petitioner contended that a person of ordinary skill in the art (POSITA) would combine these references to achieve predictable improvements. Both Ehsani and Vittone addressed the same problem of improving fuel efficiency and reducing emissions in parallel HEVs. A POSITA would have been motivated to implement Vittone’s known control strategy for managing engine transients within Ehsani’s HEV architecture to optimize its performance, a known solution to a known problem.
  • Expectation of Success: A POSITA would have had a reasonable expectation of success because combining Vittone's control algorithm with Ehsani's hardware was a simple substitution of known elements that would predictably result in improved fuel economy and reduced emissions.

Ground 2: Obviousness over Ehsani, Vittone, and Caraceni - Claim 2 is obvious over the combination of Ehsani, Vittone, and Caraceni.

• Prior Art Relied Upon: Ehsani (Patent 5,586,613), Vittone (a 1994 FIAT symposium paper), and Caraceni (SAE Technical Paper 981124).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground built upon the combination in Ground 1 to address dependent claim 2, which required the engine torque threshold value to be "no more than about 2% per revolution." Petitioner argued that Caraceni, which described a related FIAT project, provided a refinement of Vittone’s control strategy. Caraceni allegedly disclosed limiting engine torque gradients to specific values, which Petitioner’s expert converted to the "% per revolution" unit recited in the claim. The analysis showed that the majority of torque gradients disclosed by Caraceni were within the claimed 2% limit.
  • Motivation to Combine: A POSITA implementing the control strategy of Vittone would have naturally looked to a closely related publication like Caraceni for specific, optimized parameters. Since both were FIAT projects aimed at optimizing HEV control strategies, combining them was a predictable design choice to refine the system’s performance.

Ground 3: Obviousness over Kawakatsu and Vittone - Claims 1, 3, 4, and 19 are obvious over Kawakatsu in view of Vittone.

• Prior Art Relied Upon: Kawakatsu (Patent 4,335,429) and Vittone (a 1994 FIAT symposium paper).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner presented this as an alternative challenge to the independent claims. Kawakatsu allegedly disclosed a two-motor parallel HEV architecture controlled by a microcomputer with detailed operating modes designed to run the engine only under high-efficiency conditions. However, Kawakatsu taught a system with DC motors. Petitioner argued that Vittone supplied the motivation to use AC motors, which had become favored by the time of the invention for their superior performance, and also taught the same engine control strategy for managing transients as in Ground 1. For claim 4, Petitioner asserted that Kawakatsu’s figures explicitly showed operating regions where the maximum torque produced by the electric motors was larger than the maximum torque produced by the engine.
  • Motivation to Combine: A POSITA would have been motivated to modify the DC motor system in Kawakatsu to an AC motor system as taught by Vittone to gain the well-known benefits of improved efficiency and torque response. This modification, along with the integration of Vittone's control strategy, was presented as an obvious design choice to create a more modern and efficient HEV.
  • Expectation of Success: The substitution of AC motors for DC motors and the addition of the required converters was a well-understood engineering task at the time, and applying Vittone’s control strategy to the modified Kawakatsu system would predictably improve its performance.

• Additional Grounds: Petitioner asserted additional obviousness challenges, including combining Ehsani and Vittone with Fjallstrom (Patent 5,120,282) for claim 6 (adding a third electric motor for an all-wheel-drive system) and with Yamaguchi (Patent 5,865,263) for claim 12 (preheating the engine prior to starting).

4. Key Claim Construction Positions

• Petitioner proposed that the term “road load,” which appeared in all challenged claims, be construed for the purposes of the IPR as “the instantaneous torque required for propulsion of the vehicle, which may be positive or negative in value.” This construction was based on previous interpretations from district court litigation involving the patent family. This interpretation was critical to Petitioner’s argument that the "DRIVEABILITY TORQUE REQUIREMENTS" disclosed in Vittone corresponded to the claimed "road load."

5. 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.