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 describes a directly actuated fuel injector for an internal combustion engine. The invention features a piezoelectric or magnetostrictive actuator that directly controls a valve needle and incorporates a "passive hydraulic link" between the actuator and the needle to transmit force and auto-adjust for thermal expansion and 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: a valve housing, a valve member biased to a closed position, and a piezoelectric/magnetostrictive actuator to open the valve. Wirbeleit also discloses a "hydraulic transmission element" that functions as a passive link to transmit force from the actuator to the valve needle. However, Wirbeleit does not explicitly disclose that its hydraulic link is adjustable to compensate for thermal expansion and wear. Petitioner asserted that Klügl remedies this deficiency by teaching a "transmission module" with a hydraulic fluid chamber that not only passively transfers force during actuation but is also designed to allow fluid to redistribute during idle periods, thereby automatically adjusting for thermal expansion and wear.
  • Motivation to Combine: Petitioner asserted a POSITA would combine these references because Wirbeleit explicitly states its hydraulic transmission element is "not shown in detail," prompting a designer to look to known designs like Klügl for implementation. Both references disclose analogous hydraulic-based injectors with piezoelectric actuators. A POSITA would have recognized that incorporating Klügl’s self-adjusting feature would solve the well-known problems of thermal expansion and wear in Wirbeleit's injector, improving its reliability and performance.
  • Expectation of Success: The structural and functional similarities between the injectors in Wirbeleit and Klügl would have given a POSITA a reasonable expectation of success in integrating Klügl's self-adjusting hydraulic link into Wirbeleit's design.

Ground 2: Obviousness over Wirbeleit, Klügl, and Newcomb - Claim 28 is obvious over Wirbeleit and Klügl in view of 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 builds on Ground 1 to address dependent claim 28, which requires the valve housing, valve member, and actuator to be made of materials with compatible thermal expansion coefficients to reduce temperature-induced dimensional changes. Petitioner argued that Newcomb explicitly teaches this concept for a fuel injection valve. Newcomb explains it is "essential to minimize the effect of thermal expansion" and teaches selecting materials with similar thermal expansion coefficients to maintain a stable component relationship.
  • Motivation to Combine: A POSITA, already motivated to address thermal effects by combining Wirbeleit and Klügl, would further consult a reference like Newcomb, which addresses the same problem. Newcomb provides a known, complementary solution—material selection—to further enhance the thermal stability of the combined Wirbeleit/Klügl injector.

Ground 3: Obviousness over Klügl and Hayes (Alternative Claim Construction) - 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 argued in the alternative, adopting the Patent Owner's broader claim construction from district court litigation, which allegedly encompasses indirectly actuated injectors. Petitioner asserted that Klügl itself teaches an indirectly actuated injector that meets all limitations of the claims under this broader scope. Klügl’s actuator opens an intermediate servo valve, which in turn causes the main injection needle to open. Petitioner contended that Hayes, another indirectly actuated injector, provides details of structures not fully illustrated in Klügl (such as the fuel inlet port and interior chamber) and confirms how a POSITA would have understood Klügl’s design.
  • Motivation to Combine: Petitioner argued that Hayes is not used to modify Klügl but to provide elaboration on how a POSITA would understand the structure and operation of the components in Klügl that are mentioned but not shown in detail. Both references disclose functionally similar indirectly actuated injectors, motivating a POSITA to look to Hayes to understand the conventional implementation of Klügl's system.

Ground 4: Obviousness over Klügl, Hayes, and Newcomb (Alternative Claim Construction) - Claim 28 is obvious over Klügl and Hayes in view of Newcomb.

• Prior Art Relied Upon: Klügl (DE 197 08 304 A1), Hayes (Patent 5,779,149), and Newcomb (Patent 4,284,263).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground builds on the alternative theory in Ground 3 to address claim 28. As in Ground 2, Petitioner argued Newcomb teaches selecting materials with compatible thermal expansion coefficients to minimize temperature effects.
  • Motivation to Combine: For the same reasons articulated in Ground 2, a POSITA designing the indirectly actuated injector of Klügl/Hayes would have been motivated to incorporate Newcomb's material selection teachings to further improve performance and mitigate thermal expansion effects.

4. Key Claim Construction Positions

• Petitioner argued that the plain and ordinary meaning of the claims, supported by the specification and the patent's title, requires a "directly actuated" injector where the valve member itself opens a passage to the combustion chamber. This interpretation supports Grounds 1 and 2.
• In the alternative, Petitioner presented Grounds 3 and 4 based on the Patent Owner's alleged infringement theory from co-pending litigation. Under this broader interpretation, the claims encompass "indirectly actuated" injectors, where the actuator opens an intermediate valve that subsequently causes the main injection valve to open.

5. Arguments Regarding Discretionary Denial

• Petitioner argued against discretionary denial under §314(a) and the Fintiv factors, asserting that the co-pending district court litigation was in a very early stage, with no trial date set, no claim construction order issued, and minimal discovery conducted.
• Petitioner also argued that denial under §325(d) would be inappropriate because the primary prior art references, Wirbeleit and Klügl, are substantively different from the art considered during prosecution. Specifically, these references teach the claimed "passive hydraulic link" that the Examiner previously found lacking in the cited art.

6. Relief Requested

• Petitioner requests 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.