PTAB

IPR2018-00018

STIHL Inc v. ElectroJet Technologies Inc

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Electronic Engine Control With Reduced Sensor Set
  • Brief Description: The ’081 patent discloses an electronic control system for a fuel-injected internal combustion engine. The system determines engine parameters like crankshaft position and intake air mass using signals from a single intake air pressure sensor, reducing the need for additional dedicated sensors.

3. Grounds for Unpatentability

Ground 1: Obviousness over Abe and Kupske - Claims 1-12, 14-16, and 18 are obvious over Abe in view of Kupske.

  • Prior Art Relied Upon: Abe (Patent 4,866,620) and Kupske (DE 10116485).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Abe's system, comprising an ECU and an intake manifold pressure sensor, met the limitations for an engine control apparatus that determines intake air mass from a single sensory means. Abe's ECU computed the amount of intake air based on pressure measurements to control fuel injection. Petitioner contended that Kupske supplied any missing teachings related to determining engine position and speed from the same sensor. Kupske explicitly disclosed using an inlet manifold pressure sensor to generate a periodic signal, where the cycle time between pressure pulses indicated engine speed and the pulse timing could be used to arithmetically emulate the crankshaft position signal. This capability was highlighted in Kupske as a way to maintain engine operation during the failure of a dedicated crankshaft sensor. Therefore, the combination of Abe's foundational system with Kupske's position-derivation technique allegedly rendered independent claims 1, 6, 11, and 15 obvious.
    • Motivation to Combine: Petitioner contended a POSITA would have been motivated to combine the teachings for several reasons. First, a POSITA would combine them to improve the reliability of the system in Abe by incorporating the sensor redundancy function taught by Kupske, where the pressure sensor serves as an emergency backup. Second, a POSITA could replace the dedicated crank angle sensor in Abe entirely with Kupske's method to simplify the system and reduce costs, a well-known goal in the art. Both references were in the same field of automotive engine controls, addressed similar problems using similar components, and described using intake manifold pressure to determine key operating parameters.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success because the teachings were consistent, involving the use of an intake pressure sensor to provide data to a control unit for determining engine operating parameters.

Ground 2: Obviousness over Ostdiek and Vernier - Claims 1, 3, 5, 6, 8, 10-12, and 14 are obvious over Ostdiek in view of Vernier.

  • Prior Art Relied Upon: Ostdiek (Patent 5,092,301) and Vernier (Patent 5,261,369).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner asserted that Ostdiek taught a simple fuel control system requiring only a pressure sensor to determine an engine's fuel requirements. Ostdiek's microprocessor measured the time between periodic pressure fluctuations to determine the engine's operational cycle time (and thus speed) and calculated the quantity of inhaled air from the pressure waveform. To the extent Ostdiek did not expressly teach how to determine the specific angular position of the crankshaft from the pressure signal, Petitioner argued Vernier provided this disclosure. Vernier taught that its controller could determine engine position by detecting characteristic points in the pressure signal, such as "inflection points" corresponding to the opening of the intake valve and maxima corresponding to the piston reaching top-dead-center.
    • Motivation to Combine: A POSITA would have been motivated to incorporate Vernier's more sophisticated position-detection capability into Ostdiek's system to enhance the precision of the fuel injection control, which relies on accurate engine position information. Both references explicitly described the cost and simplicity advantages of using a single pressure sensor to acquire multiple operating parameters. A POSITA reading Ostdiek's disclosure would have naturally looked to known techniques, such as those in Vernier, to extract more precise positional data from the same pressure signal to improve performance.
    • Expectation of Success: The combination was presented as obvious to try with a high expectation of success because both references disclosed engine control systems using similar components for similar functions, and a POSITA would have recognized their teachings as consistent and complementary.

  • Additional Grounds: Petitioner asserted additional obviousness challenges based on the same primary combinations, further in view of the knowledge of a POSITA. These grounds argued for the obviousness of incorporating well-known components like a "crank trigger" (for claims 13 and 17) or using the intake pressure signal to determine engine load (for claims 2, 4, 7, 9, and 15-18), asserting these were common practices and simple substitutions of known elements.

4. Key Claim Construction Positions

  • Petitioner argued that several claim terms reciting "means" followed by functional language (e.g., "pressure sensor means for developing periodic sensor voltage timing pulses," "pressure sensor means for measuring intake air mass") should be construed as means-plus-function limitations under pre-AIA 35 U.S.C. §112, 6th paragraph.
  • Petitioner asserted the corresponding structure disclosed in the ’081 patent for performing these functions was not merely the pressure sensor itself, but an intake pressure sensor in combination with an Electronic Control Unit (ECU). This construction was central to the invalidity arguments, as it allowed Petitioner to map the processing functions of the prior art ECUs to the claimed "means."

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-18 of the ’081 patent as unpatentable.