PTAB

IPR2015-00785

Ford Motor Co v. Paice LLC

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Hybrid vehicles
  • Brief Description: The ’634 patent describes a control strategy and topology for a hybrid electric vehicle (HEV). The system uses at least one electric motor and an internal combustion engine, with a controller that operates the engine primarily under conditions of high efficiency based on the vehicle's instantaneous torque demands.

3. Grounds for Unpatentability

Ground 1: Claims 241, 252-254, 256, 258-259, 263, and 265 are obvious over Severinsky in view of Anderson.

  • Prior Art Relied Upon: Severinsky (5,343,970) and Anderson (SAE Technical Paper 950493).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Severinsky, which is cited in the ’634 patent itself, discloses the core method for controlling a hybrid vehicle as claimed. Severinsky teaches a control system that determines the required torque (i.e., "road load") and operates either the electric motor (at low torque requirements) or the engine (at high torque requirements, where it is most efficient). However, Severinsky does not explicitly teach limiting the rate of engine torque change to maintain a stoichiometric air-fuel ratio. Anderson, a technical paper on HEV control strategies, explicitly addresses this gap. Anderson teaches that to minimize emissions—a key goal of HEVs—it is crucial to maintain a stoichiometric ratio, and that this is difficult during rapid engine transients. Anderson’s solution is to use a hybrid strategy that allows only slow transients, thereby limiting the rate of change of torque output.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine these references to solve a known problem. Severinsky’s stated goal was to reduce pollutant emissions. Anderson directly addressed this goal by teaching that managing engine transients to maintain a stoichiometric ratio is an effective method for reducing emissions in HEVs. A POSITA would have been motivated to apply Anderson’s well-understood transient control strategy to Severinsky’s system to predictably improve its emission performance.
    • Expectation of Success: A POSITA would have had a high expectation of success, as the combination involved applying a known emission-control technique to a compatible HEV system to achieve the predictable result of reduced emissions.

Ground 2: Claims 80, 91-92, 99, 112, 114, 125-126, 132, and 145 are obvious over Severinsky in view of Frank.

  • Prior Art Relied Upon: Severinsky (5,343,970) and Frank (5,842,534).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground addresses claims similar to those in Ground 1 but adds limitations related to hysteresis control for switching the engine on and off. Petitioner asserted that Severinsky teaches the foundational torque-based mode switching but does not explicitly disclose methods to prevent "chattering" (rapid on/off cycling of the engine) when the road load is near the switching setpoint. Frank addresses this exact issue in the context of a parallel HEV. Frank teaches two well-known hysteresis techniques to prevent frequent engine cycling: (1) using a time delay, where the engine only starts or stops after the road load has been above or below the threshold for a predetermined time; and (2) using separate "on" and "off" thresholds (e.g., turn on at 65% MTO, turn off at 60% MTO).
    • Motivation to Combine: A POSITA would combine Frank’s hysteresis control with Severinsky’s system to improve efficiency and durability. Excessive engine cycling, as Frank notes, is inefficient, increases emissions, and reduces component life. Since improving fuel economy and reducing emissions were stated goals of Severinsky, a POSITA would have been motivated to incorporate a standard, well-known control strategy like hysteresis from a reference like Frank to prevent this undesirable behavior.
    • Expectation of Success: The combination was a simple application of a fundamental control engineering principle (hysteresis) to a known problem (system chattering) in the same technical field, ensuring a high expectation of success.

Ground 3: Claims 257, 260-262 are obvious over Severinsky and Anderson in view of Lateur.

  • Prior Art Relied Upon: Severinsky (5,343,970), Anderson (SAE Technical Paper 950493), and Lateur (5,823,280).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground builds on the combination of Severinsky and Anderson by adding features taught in Lateur, primarily related to cruise control and specific drivetrain components. Petitioner argued that the base system from Severinsky/Anderson lacks specific teachings on implementing cruise control. Lateur explicitly discloses a cruise control system for an HEV, where a microprocessor maintains a desired vehicle speed by modulating torque from the engine and/or electric motor in response to changing road load. Lateur also discloses using a clutch to decouple the engine during warm-up (allowing electric-only operation) and a planetary gear set acting as a variable-ratio transmission.
    • Motivation to Combine: The motivation was to add a common, desirable feature to improve operating convenience and fuel economy, both stated goals of Severinsky. Cruise control was a well-established feature in conventional vehicles, and a POSITA designing a competitive HEV would have been motivated to include it. Lateur provides a clear blueprint for its implementation in a hybrid context. The engine warm-up strategy from Lateur would also be combined to further reduce emissions, another key design goal.
    • Expectation of Success: Implementing a known feature like cruise control using established software algorithms in Severinsky’s microprocessor-controlled system would have been a routine design choice with a high expectation of success.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including combinations of Severinsky, Frank, and Anderson (Ground 4) and Severinsky, Frank, and Lateur (Ground 5), which relied on similar rationales to combine the teachings for emissions control, hysteresis, and driver convenience features.

4. Key Claim Construction Positions

  • "road load (RL)": Petitioner proposed construing this term as "the amount of instantaneous torque required to propel the vehicle, be it positive or negative." This construction was argued to be consistent with prior PTAB decisions and central to mapping the claims onto prior art that teaches torque-based control.
  • "setpoint (SP)": Petitioner proposed this term be construed as a "predetermined torque value." This contrasts with a broader construction of a "potentially variable value" from district court litigation. Petitioner argued its narrower construction was required by the patent’s specification and prosecution history, where the setpoint is consistently compared against torque-based values like road load.

5. Key Technical Contentions (Beyond Claim Construction)

  • Torque-Based vs. Speed-Based Control in Severinsky: A central technical contention was that the primary reference, Severinsky, teaches a torque-based control strategy. Petitioner preemptively refuted the Patent Owner's anticipated argument that Severinsky's control logic is based on vehicle speed. Petitioner supported its position by citing admissions within the challenged ’634 patent itself, which explicitly state that the system in Severinsky operates in different modes "depending on the torque required." This characterization was critical to establishing that Severinsky’s fundamental control strategy aligned with the patent claims.

6. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 80, 91, 92, 97, 99, 107, 108, 110, 112, 114, 125, 126, 130, 132, 140, 141, 143, 145, 241, 252-254, 256-263, and 265 of the ’634 patent as unpatentable.