Robert Bosch LLC v. Westport Fuel Systems Canada Inc

1. Case Identification

• Case #: IPR2023-00293
• Patent #: 6,575,138
• Filed: December 14, 2022
• Petitioner(s): Robert Bosch LLC, and Mercedes-Benz USA, LLC
• Patent Owner(s): Westport Fuel Systems Canada Inc.
• Challenged Claims: 1-3, 6, 13-14, 17-21, 26-28, and 41

2. Patent Overview

• Title: Directly Actuated Injection Valve
• Brief Description: The ’138 patent discloses a fuel injector for an internal combustion engine. The invention is described as a "directly actuated" injector that uses a piezoelectric or magnetostrictive actuator to control a valve needle, and incorporates a "passive hydraulic link" to transmit force from the actuator to the needle. This link is designed to be passive during actuation but allows for auto-adjustment during periods of rest to compensate for thermal expansion and component wear.

3. Grounds for Unpatentability

Ground 1: Obviousness over Wirbeleit and Klügl - Claims 1-3, 6, 13-14, 17-21, 26-27, and 41 are obvious over Wirbeleit in view of Klügl.

• Prior Art Relied Upon: Wirbeleit (Patent 5,479,902) and Klügl (DE 197 08 304 A1).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Wirbeleit teaches a directly actuated fuel injector with all the core components required by independent claim 1, including a valve housing, a valve member that seals against a valve seat, a biasing spring, a piezoelectric/magnetostrictive actuator, and a "hydraulic transmission element" that functions as a passive hydraulic link. However, Wirbeleit did not explicitly disclose that its hydraulic link was auto-adjustable to compensate for wear and thermal expansion. Klügl was argued to supply this missing element, as it teaches a fuel injector with a "transmission module" containing hydraulic fluid in a chamber that is passive during actuation but allows fluid to migrate to a compensating chamber during idle periods to "automatic[ally] adjust[]" for "thermal expansion differences and gradual wear."
  • Motivation to Combine: Petitioner contended that a person of ordinary skill in the art (POSITA), when implementing the hydraulic link in Wirbeleit (which is stated to be "not shown in detail"), would have looked to known designs to address common problems like thermal expansion and wear. A POSITA would combine Klügl’s auto-adjusting transmission module with Wirbeleit’s directly actuated injector because they are structurally and functionally analogous systems aimed at solving the same technical challenges. The combination would have been a predictable and routine design improvement.
  • Expectation of Success: A POSITA would have a reasonable expectation of success in combining the references because both relate to fuel injectors for engines and employ similar piezoelectric actuators and hydraulic force transmission principles.

Ground 2: Obviousness over Wirbeleit, Klügl, and Newcomb - Claim 28 is obvious over Wirbeleit, Klügl, and Newcomb.

• Prior Art Relied Upon: Wirbeleit (Patent 5,479,902), Klügl (DE 197 08 304 A1), and Newcomb (Patent 4,284,263).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground built upon Ground 1 to address dependent claim 28, which requires the valve housing, valve member, and actuator assembly to be made from materials with compatible thermal expansion coefficients. Petitioner asserted that while Wirbeleit and Klügl teach the base invention, Newcomb explicitly teaches the benefits of this material selection strategy. Newcomb discloses a fuel injection valve where components are made from materials with matching or compatible thermal coefficients to "minimize the effect of thermal expansion."
  • Motivation to Combine: A POSITA seeking to further enhance the thermal stability of the injector design from Ground 1 would be motivated to incorporate the teachings of Newcomb. Newcomb presented this as an "essential" design consideration for injectors and a known, cost-effective method for improving dimensional stability, providing a clear motivation for its inclusion.

Ground 3: Obviousness over Klügl and Hayes - Claims 1-3, 6, 13-14, 17-21, 26-27, and 41 are obvious over Klügl in view of Hayes.

• Prior Art Relied Upon: Klügl (DE 197 08 304 A1) and Hayes (Patent 5,779,149).

• Core Argument for this Ground:

  • Prior Art Mapping: This ground was presented as an alternative based on the Patent Owner’s broader claim interpretation from a related district court case, under which the claims encompass indirectly actuated injectors. Petitioner argued that under this interpretation, Klügl—an indirectly actuated injector—teaches nearly all claim limitations, including the passive, auto-adjusting hydraulic link. Hayes, another indirectly actuated injector, was used to provide context and elaborate on how a POSITA would understand the structure of components not detailed in Klügl’s figures, such as the fuel inlet port and interior fuel chamber.
  • Motivation to Combine: Petitioner asserted that a POSITA reading Klügl would look to conventional designs like Hayes to understand how to implement the undetailed portions of its injector. This was not a modification of Klügl but rather an elaboration based on known art, showing how Klügl inherently taught the claimed invention under the broader construction.

• Additional Grounds: Petitioner asserted an additional obviousness challenge for claim 28 (Ground 4) over Klügl and Hayes in further view of Newcomb, which parallels the logic of Ground 2 but applies it to the indirectly actuated injector design of Ground 3.

4. Key Claim Construction Positions

• Petitioner argued that two distinct claim construction scenarios exist. The primary argument (used for Grounds 1 and 2) was that the claims should be given their plain and ordinary meaning, which requires a "directly actuated" injector where the "valve member" directly opens a path to the combustion chamber.
• As an alternative, Petitioner presented arguments (for Grounds 3 and 4) based on the Patent Owner's alleged position in district court litigation. This position interprets the claims more broadly to cover "indirectly actuated" injectors, where the actuator and valve member operate an intermediate control valve rather than the final injection valve. Petitioner argued this construction is incorrect but demonstrated that the claims are unpatentable even under this broader scope.

5. Arguments Regarding Discretionary Denial

• §314(a) (Fintiv): Petitioner argued against discretionary denial under Fintiv, asserting that the petition presents "compelling evidence of unpatentability." It was also noted that the co-pending district court litigations were in very early stages, with no trial scheduled or claim construction orders issued, which weighs in favor of institution.
• §325(d): Petitioner argued that denial would be inappropriate because the primary prior art references, Wirbeleit and Klügl, were never cited or considered by the examiner during the original prosecution. These references were argued to be substantively different from the art of record because they teach the claimed "passive hydraulic link" that the applicant previously used to distinguish over the cited prior art.

6. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 1-3, 6, 13-14, 17-21, 26-28, and 41 of the ’138 patent as unpatentable.