Invalidity dossier
US 4308835
Closed-loop fluidic control system for internal combustion engines
Current assignee: Individual
Added 9/23/2026, 8:12:19 PM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 4,308,835 A
Title: Closed-loop fluidic control system for internal combustion engines
Patent number: US4308835A
Inventor: Harold G. Abbey
Assignee: Original assignee listed as "Individual"; current assignee listed as "Individual." Google Patents notes the listed assignees may be inaccurate and that it has performed no analysis or warranty as to their accuracy.
Key dates (as listed; priority and legal status are stated by the source to be assumptions, not legal conclusions):
- Priority date: 1980-01-25 (claimed from US06/115,551, externally linked to patent US4250856A)
- Filing date: 1980-12-10 (application US06/214,626)
- Publication/grant: 1982-01-05
- Legal status: Expired – Lifetime (anticipated expiration 1999-01-05)
Purpose and plain-language scope (from the supplied excerpt): The invention relates generally to variable Venturi carburetion systems for supplying a fuel-air mixture to an automotive internal combustion engine, and more particularly to a closed-loop fluidic control servo system that automatically regulates the flow of fuel and air admitted into a variable Venturi structure. The aim is to maintain a desired fuel-to-air ratio under varying load and speed, thereby seeking higher combustion efficiency, increased fuel economy, and reduced pollutant emissions. The excerpt's background describes carburetor fundamentals (Venturi pressure drop drawing fuel through a jet, atomization, vaporization), the compromise inherent in sizing Venturis to midrange engine capacity, an alternative carburetor using manifold vacuum with a tapered needle fuel valve, and the desirability of holding the mixture near stoichiometric across idle, slow, cruising, and high-speed modes. It also describes exhaust "Lambda" sensors generating voltage as a function of air-fuel mixture, and notes that the exhaust-sensor signal is applied to an electronic control (text truncated).
Not established by the excerpt: The full claim set, dependent claims, and claim language; the complete detailed description and drawings; the specific fluidic servo structure; prosecution history; total prior-art citations and their teachings; and the identity, ownership, or litigation status beyond what is quoted.
Generated 10/1/2026, 9:41:30 PM
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Litigation summary
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Proceedings on file (0)
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No PTAB proceedings on file. This patent has not been challenged via IPR, PGR, or CBM. The absence is itself a signal — well-asserted patents eventually attract IPRs. The LLM analysis below may surface filings the ODP feed hasn’t indexed yet.
PTAB challenges
AIA trial proceedings at the USPTO Patent Trial and Appeal Board — IPR, PGR, and CBM. Petitioners, judge panels, claim-level invalidation outcomes from Final Written Decisions, and Federal Circuit appeals. The single most important defensive datapoint after litigation history.
Assignment history
Inventors, original assignee, and the chain of ownership recorded with the USPTO — including the correspondent attorney who recorded each assignment, since shell-LLC chains often share one repeat-player attorney even when the entity names look unrelated. Surfaces NPE / patent-troll patterns: shell-entity transfers, known asserters in the chain, repeat correspondent fingerprints, pre-litigation assignments, and bankruptcy fire-sales.
Prior art
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Obviousness
Combinations of prior art that suggest the claimed invention would have been obvious under 35 U.S.C. § 103.
Extensions
Patent term adjustments, term extensions, continuations, divisionals, family members, and expiration dates.
Derivative works
Defensive disclosure: derivative variations of each claim designed to render future incremental improvements obvious or non-novel.