DCT
3:25-cv-50026
Diesel Tech LLC v. Caterpillar Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Diesel Technologies LLC (Delaware)
- Defendant: Caterpillar, Inc. (Delaware)
- Plaintiff’s Counsel: Devlin Law Firm LLC
- Case Identification: 3:25-cv-50026, N.D. Ill., 01/17/2025
- Venue Allegations: Venue is alleged based on Defendant’s established places of business in the district, including corporate offices and technical centers.
- Core Dispute: Plaintiff alleges that Defendant’s diesel engines equipped with Exhaust After-Treatment Systems infringe a patent related to a method for regenerating diesel particulate filters by chemically reducing accumulated ash.
- Technical Context: The technology addresses the problem of non-combustible ash accumulation in diesel particulate filters, which clogs filters, degrades engine performance, and is a critical issue for meeting modern vehicle emissions standards.
- Key Procedural History: The complaint does not reference any prior litigation, inter partes review proceedings, or licensing history related to the patent-in-suit. Willfulness allegations are based on notice provided by the filing of the instant complaint.
Case Timeline
| Date | Event |
|---|---|
| 2003-12-18 | Priority Date for U.S. Patent 8,474,246 |
| 2013-07-02 | Issue Date for U.S. Patent 8,474,246 |
| 2025-01-17 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 8,474,246 - METHOD OF OPERATING A PARTICLE FILTER IN THE EXHAUST SYSTEM OF A MOTOR VEHICLE'S INTERNAL COMBUSTION ENGINE
- Patent Identification: U.S. Patent No. 8,474,246 (“the ’246 Patent”), “METHOD OF OPERATING A PARTICLE FILTER IN THE EXHAUST SYSTEM OF A MOTOR VEHICLE'S INTERNAL COMBUSTION ENGINE,” issued July 2, 2013.
The Invention Explained
- Problem Addressed: Diesel Particulate Filters (DPFs) are effective at trapping soot, which can be periodically burned off. However, they also accumulate non-combustible inorganic "ash" from engine oil and fuel additives. This ash buildup progressively clogs the filter, increasing exhaust backpressure and eventually necessitating costly filter replacement or off-vehicle cleaning. (’246 Patent, col. 1:30-41). Prior art methods to remove ash were described as complex and requiring an interruption of the vehicle's operation. (’246 Patent, col. 1:45-53).
- The Patented Solution: The patent discloses a method to reduce the amount of collected ash while the vehicle is in operation. The method involves heating the particle filter and supplying a "reducing agent" (such as hydrocarbons from fuel) along with the exhaust gas. This agent is intended to create a chemically reducing environment that reacts with the non-metallic components of the ash (e.g., sulfates, phosphates), converting them into volatile compounds that are then expelled from the filter with the exhaust flow. (’246 Patent, Abstract; col. 1:60-2:4; Fig. 2).
- Technical Importance: This technology purports to enable an in-situ ash-cleaning process, thereby extending the operational life of a DPF, reducing long-term maintenance costs, and aiding compliance with stringent emissions regulations. (Compl. ¶¶13, 18).
Key Claims at a Glance
- The complaint asserts infringement of independent claim 1 and dependent claims 2-4 and 7. (Compl. ¶28).
- Independent Claim 1 contains the following essential elements:
- A method of operating a particle filter that collects soot and ash and is periodically reconditioned by a "soot-burn off procedure."
- The method comprises an "ash reducing procedure" that includes the steps of:
- Heating the particle filter.
- Supplying a "reducing agent" to the filter with the exhaust gas.
- The reducing agent "reacts with the ash deposits so as to chemically convert" them.
- This conversion results in "at least non-metallic constituent parts of the ash deposits" being "carried out of the particle filter by the exhaust gas."
III. The Accused Instrumentality
Product Identification
- The "Accused Instrumentalities" are identified as Caterpillar's Exhaust After-Treatment System (EATS) that includes a Diesel Particulate Filter (DPF), as used in the Caterpillar C9.3 ACERT Tier 4 Engine. The complaint also identifies the Caterpillar C13, C15, and C18 ACERT Tier 4 Engines as potentially infringing products with the same functionality. (Compl. ¶28).
Functionality and Market Context
- The complaint alleges these engine systems collect soot and ash and undergo a reconditioning process. (Compl. ¶29). The infringement theory is premised on the allegation that this reconditioning process includes a method of heating the filter and using a reducing agent (fuel) to chemically convert and clear ash, thereby infringing the ’246 Patent. (Compl. ¶¶29-36). The complaint posits that these systems are commercially significant for enabling Caterpillar's engines to comply with modern emissions standards. (Compl. ¶18).
- No probative visual evidence provided in complaint.
IV. Analysis of Infringement Allegations
The complaint alleges infringement of claims 1-4 and 7, with the narrative theory for claim 1 forming the basis for the infringement case. (Compl. ¶¶28-30).
’246 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A method of operating a particle filter...which collects soot and ashes and is reconditioned in intervals by a burn off procedure... | The Accused Instrumentalities operate a particle filter that collects soot and ash and is reconditioned via a burn-off procedure. | ¶29 | col. 8:10-17 |
| ...reducing, in an ash reducing procedure (A), the mass of the ash in the filter by heating the filter... | The accused method involves reducing the mass of the ash by heating the filter. | ¶29 | col. 8:20-21 |
| ...and supplying to the filter along with the exhaust gas of the engine a reducing agent... | The accused method supplies a reducing agent to the filter along with the exhaust gas. | ¶29 | col. 8:22-23 |
| ...to chemically convert the ash such that parts of the converted ash are carried out by the exhaust gas. | The supplied reducing agent chemically converts the ash, and parts of the converted ash are then carried out by the exhaust gas. | ¶29 | col. 8:23-27 |
Identified Points of Contention
- Scope Questions: The patent distinguishes between a "soot-burn off procedure" and an "ash reducing procedure." (’246 Patent, col. 8:40-48). A central question may be whether the accused Caterpillar systems perform two distinct procedures, or a single regeneration procedure. The analysis may focus on whether a standard soot regeneration cycle, which typically uses an oxidizing environment, can also be characterized as the claimed "ash reducing procedure," which the patent suggests occurs in a chemically "reducing atmosphere." (’246 Patent, col. 7:41-43).
- Technical Questions: The complaint asserts that the accused systems "chemically convert the ash." (Compl. ¶29). A key evidentiary question will be whether the complaint provides sufficient factual support for this conclusion. The court may need to consider what chemical reactions actually occur within the accused DPFs and whether those reactions align with the patent's teaching of converting non-metallic ash components (e.g., sulfates and phosphates) into volatile compounds. (’246 Patent, col. 5:12-18).
V. Key Claim Terms for Construction
The Term: "reducing agent"
- Context and Importance: This term is central to the claimed invention. Its construction will determine whether the substances used in the accused systems—allegedly fuel (Compl. ¶31)—qualify. Practitioners may focus on this term because the patent contrasts the "reducing" function for ash with the oxidizing function for soot, raising a question about the required chemical properties of the agent.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification states that "in principle, any substance may be used which can cause the desired chemical conversion," including "hydrocarbons." (’246 Patent, col. 2:22-25). Dependent claim 2 further specifies that "a fuel" can be employed as the reducing agent. (’246 Patent, col. 8:28-31).
- Evidence for a Narrower Interpretation: The patent repeatedly frames the generation of the reducing agent in the context of creating specific chemical conditions, such as "under-stoichiometric operation of the internal combustion engine" or a "reforming, cracking or splitting process." (’246 Patent, col. 2:60-67, 5:60-63). The patent also explicitly contrasts the "oxidizing condition under which the soot burn-off occurs" with the "reducing atmosphere" required for the ash procedure, suggesting the "reducing agent" must be capable of creating such an environment. (’246 Patent, col. 7:39-43).
The Term: "ash reducing procedure (A)"
- Context and Importance: The claim requires this procedure as a distinct step. The infringement analysis will turn on whether Caterpillar's regeneration cycle constitutes this specific, named procedure, or if it is only a "soot-burn off procedure (R)" that may have an incidental effect on ash.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: Dependent claim 7 states the "ash reducing procedure (A) is performed in connection with a soot-burn-off procedure (R)." (’246 Patent, col. 8:46-48). Plaintiff may argue "in connection with" allows for the procedures to be concurrent or integrated.
- Evidence for a Narrower Interpretation: Claim 6 describes initiating the "ash reducing procedure (A)" only after a "soot burn-off procedure (R)" is completed and if flow resistance remains high. (’246 Patent, col. 8:40-45). Furthermore, Figure 2 graphically depicts the soot burn-off procedures (R) as separate and distinct events from the singular "ash reducing procedure (A)." (’246 Patent, Fig. 2). This could support an interpretation requiring two sequential and separately triggered events.
VI. Other Allegations
- Indirect Infringement: The complaint alleges induced infringement under 35 U.S.C. § 271(b), asserting that Caterpillar provides "instruction materials, training, and services" that actively encourage and instruct customers and partners to use the accused engines in a manner that directly infringes the ’246 Patent. (Compl. ¶¶41-42).
- Willful Infringement: The willfulness allegation is based entirely on post-suit conduct. The complaint alleges that Caterpillar’s infringement became willful "since receiving notice of this Complaint." (Compl. ¶43).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of procedural distinction: does the claim language, as informed by the specification and Figure 2, require a distinct "ash reducing procedure" that is separate in time or trigger from a "soot burn-off procedure"? The case may depend on whether the accused Caterpillar systems can be shown to perform such a discrete, claimed procedure, or if they only perform a single, unified regeneration cycle.
- A key evidentiary question will be one of chemical function: does the regeneration process in the accused engines create the chemically "reducing" environment required by the patent to convert non-metallic ash components? The plaintiff will need to provide evidence that moves beyond conclusory allegations to demonstrate that the specific chemical conversions taught by the patent actually occur in the accused systems.