DCT
3:25-cv-03568
Acheron Ventures LLC v. Kubota North America Corp
Key Events
Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Acheron Ventures LLC (Texas)
- Defendant: Kubota North America Corporation (Delaware) and Kubota Tractor Corporation (California)
- Plaintiff’s Counsel: Cherry Johnson Siegmund James PC
- Case Identification: 3:25-cv-03568, N.D. Tex., 12/31/2025
- Venue Allegations: Plaintiff alleges venue is proper in the Northern District of Texas because Defendant Kubota has a regular and established place of business in the district and has committed the alleged acts of infringement there.
- Core Dispute: Plaintiff alleges that Defendant’s tractors infringe patents related to engine warning systems that alert an operator to a "pre-overheat" condition before catastrophic engine damage occurs.
- Technical Context: The technology addresses the problem of conventional engine temperature gauges in heavy-duty vehicles, which often only provide a warning when the engine has already reached a damaging temperature, by introducing an intermediate warning threshold.
- Key Procedural History: The complaint does not reference any prior litigation, inter partes review proceedings, or licensing history related to the patents-in-suit.
Case Timeline
| Date | Event |
|---|---|
| 2014-12-03 | Priority Date for ’511 and ’782 Patents |
| 2018-11-06 | U.S. Patent No. 10,119,511 Issues |
| 2020-09-22 | U.S. Patent No. 10,781,782 Issues |
| 2025-12-31 | Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 10,119,511 - *Engine pre-overheat sensor and warning system*
The Invention Explained
- Problem Addressed: The patent’s background section describes a drawback of conventional temperature gauges in heavy-duty vehicles, which are prone to overheating due to debris clogging ventilation systems. These gauges typically only alert an operator when the engine reaches a “red zone” temperature, by which time costly or irreparable damage may have already occurred (Compl. ¶11; ’511 Patent, col. 1:26-54).
- The Patented Solution: The invention proposes a "pre-overheat" warning system. It establishes a "pre-overheat temperature" that is higher than the vehicle's normal "steady-state" operating temperature but lower than the damaging "redzone overheat temperature." A controller monitors a temperature sensor and activates a warning alarm (e.g., a light, sound, or vibration) when this intermediate pre-overheat threshold is crossed, providing the operator with an early warning to take corrective action before engine damage occurs (’511 Patent, Abstract; col. 2:13-33). The system's components are illustrated in the block diagram of Figure 2 (’511 Patent, Fig. 2).
- Technical Importance: This approach aims to shift engine temperature monitoring from a reactive, damage-indicating system to a proactive, damage-prevention system, which is particularly valuable for high-cost agricultural and industrial machinery (’511 Patent, col. 1:20-25).
Key Claims at a Glance
- The complaint asserts at least Claim 1 of the ’511 Patent (Compl. ¶18).
- Independent Claim 1 requires:
- A temperature sensor configured to provide a temperature reading in a running vehicle.
- A warning alarm configured to provide a visible, audible, or tactile warning signal.
- A controller configured to engage the warning alarm if the temperature reading exceeds a "vehicle pre-overheat temperature."
- The "vehicle pre-overheat temperature" is defined as being (1) greater than the vehicle's "steady-state temperature" and (2) less than the vehicle's "redzone temperature."
U.S. Patent No. 10,781,782 - *Engine pre-overheat sensors and warning system*
The Invention Explained
- Problem Addressed: The ’782 Patent addresses the same problem as the ’511 Patent: conventional warning systems alert operators too late to prevent engine damage from overheating, as the warning often coincides with the engine reaching a "red zone" temperature where damage is already occurring (’782 Patent, col. 1:53-64).
- The Patented Solution: The patented solution is a pre-overheat system that provides a warning when engine temperature exceeds a "pre-overheat temperature." As described in the specification, this threshold is set above the normal operating temperature but below the temperature at which engine damage is likely, thereby enabling preventative action by the operator (’782 Patent, Abstract; col. 2:18-37).
- Technical Importance: The invention provides a method for early detection of rising engine temperatures, allowing operators to address issues like clogged vents or low coolant before they lead to significant mechanical failure (’782 Patent, col. 2:44-52).
Key Claims at a Glance
- The complaint asserts at least Claim 1 of the ’782 Patent (Compl. ¶25).
- Independent Claim 1 requires:
- A temperature sensor configured to provide a temperature reading in a running vehicle.
- A warning alarm configured to provide a warning signal when the temperature reading exceeds a "vehicle pre-overheat temperature."
- The "vehicle pre-overheat temperature" is defined as being (a) greater than the vehicle's "steady-state temperature" and (b) less than the vehicle's "redzone temperature."
III. The Accused Instrumentality
Product Identification
The accused instrumentalities are Kubota tractors that include "engine pre-overheat sensors and warning system technologies" (Compl. ¶8). The complaint specifically identifies the Kubota BX23S Sub-Compact Tractor as an exemplary accused product (Compl. ¶12).
Functionality and Market Context
The complaint alleges the accused products contain a "pre-overheat system" that includes a temperature sensor for engine readings, a visual warning alarm in the form of an illuminated indicator, and a controller. This system is allegedly configured to engage the alarm to notify an operator of rising temperatures "before the engine is damaged" (Compl. ¶12). No probative visual evidence provided in complaint.
IV. Analysis of Infringement Allegations
The complaint references claim charts in Exhibits 3 and 4 that were not publicly filed with the complaint (Compl. ¶¶ 21, 28). The following summary is based on the narrative allegations.
’511 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a. a temperature sensor configured to provide a temperature reading in a running vehicle... | The accused products include "a built-in temperature sensor that provides engine temperature readings in a running tractor..." | ¶12 | col. 5:57-62 |
| b. a warning alarm configured to provide one or more of: (1) a visible warning signal... | The accused products include "a warning alarm that provides a visual warning in the form of an illuminated indicator..." | ¶12 | col. 5:5-8 |
| c. a controller configured to engage the warning alarm if the temperature reading exceeds a vehicle pre-overheat temperature... wherein the vehicle pre-overheat temperature is... greater than a vehicle steady-state temperature... and less than a vehicle redzone temperature... | The accused products include "...a controller that is configured to engage the warning alarm in order to notify a vehicle operator of rising temperatures before the engine is damaged." | ¶12 | col. 3:3-8 |
’782 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a. a temperature sensor configured to provide a temperature reading in a running vehicle... | The accused products include "a built-in temperature sensor that provides engine temperature readings in a running tractor..." | ¶12 | col. 6:55-63 |
| b. a warning alarm configured to provide a warning signal when the temperature reading exceeds a vehicle pre-overheat temperature, wherein the vehicle pre-overheat temperature is... greater than a vehicle steady-state temperature... and less than a vehicle redzone temperature... | The accused products include "...a warning alarm that provides a visual warning... and a controller that is configured to engage the warning alarm in order to notify a vehicle operator of rising temperatures before the engine is damaged." | ¶12 | col. 7:1-12 |
Identified Points of Contention
- Scope Questions: A central dispute may concern the definitions of "pre-overheat temperature" and "steady-state temperature." The analysis may question whether the accused Kubota system's warning threshold is merely a conventional high-temperature alert or if it functions specifically as an intermediate warning set between a defined "steady-state" and a "redzone" temperature, as the claims require.
- Technical Questions: The complaint alleges in functional terms that the accused system warns "before the engine is damaged" (Compl. ¶12). A key technical question for the court will be whether the accused Kubota tractors actually implement the specific three-tiered temperature logic (steady-state < pre-overheat < redzone) taught in the patents, or if their warning systems operate on a different technical principle. The complaint does not provide specific data on the accused products' warning temperature thresholds.
V. Key Claim Terms for Construction
The Term: "pre-overheat temperature"
Context and Importance: This term is the core of the asserted claims' novelty. Its construction will likely determine the scope of infringement, distinguishing the patented invention from conventional overheat alarms. Practitioners may focus on this term because the dispute will hinge on whether the accused device's warning threshold meets this specific definition.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language itself provides a relational definition: "greater than a vehicle steady-state temperature" and "less than a vehicle redzone temperature" (’511 Patent, cl. 1). This could support an interpretation covering any warning system that triggers in this intermediate range, regardless of the specific temperature value.
- Evidence for a Narrower Interpretation: The specification provides specific, quantitative examples, such as "about 12 degrees above the steady-state temperature for many applications" (’511 Patent, col. 2:31-33) and "5 degrees above the steady-state temperature" (’782 Patent, col. 2:35-37). This language could be used to argue that the term requires a specific, engineered offset from a baseline, rather than any arbitrary point between the steady-state and redzone temperatures.
The Term: "steady-state temperature"
Context and Importance: This term serves as the baseline for defining the "pre-overheat temperature." Infringement requires the accused system to operate relative to this baseline. If an accused system's warning is not tied to a measurable "steady-state temperature," a finding of non-infringement may be possible.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification defines it as "the temperature that is maintained (substantially constant) by a temperature control system of the vehicle while the vehicle is functioning normally and running in normal environmental conditions" (’511 Patent, col. 2:21-25). This functional language may support a broad application to various engines' normal operating temperatures.
- Evidence for a Narrower Interpretation: The specification notes that "The constant steady-state temperature... is around 210 degrees Fahrenheit for many heady-duty vehicles" (’511 Patent, col. 3:56-62). A defendant might argue that this example limits the term to a relatively stable temperature, and systems that normally operate with wider temperature fluctuations do not have a "steady-state temperature" as contemplated by the patent.
VI. Other Allegations
- Indirect Infringement: The complaint does not contain allegations of fact to support claims for either induced or contributory infringement; the infringement counts are limited to direct infringement (Compl. ¶¶ 18, 25).
- Willful Infringement: The complaint does not allege any facts that would typically support a claim for willful infringement, such as pre-suit knowledge of the patents-in-suit. The requests for enhanced damages are included only in the general damages and prayer for relief sections (Compl. ¶¶ 22, 29, and Prayer for Relief ¶E).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of definitional scope: Will the term "pre-overheat temperature" be construed broadly to cover any warning that occurs between a normal operating state and a damage-inducing state, or will it be limited to a specific, engineered temperature threshold calculated in relation to a defined "steady-state temperature"?
- A key evidentiary question will be one of technical implementation: What evidence will be presented to demonstrate that the accused Kubota tractors' warning systems operate based on the specific three-tiered temperature logic (steady-state < pre-overheat < redzone) required by the claims, as distinct from a conventional high-temperature warning system that operates on a different principle?