Marine Engine NOx Reduction Patents: Top Companies & Trends 2026
- 34.5% of all 5,168 records sit with just five assignees, and the top ten hold 50.5% — this field is concentrated, not fragmented.
- Filing fell 67% from 2021 to 2024 (107 to 35 records), the last span the data can treat as complete before publication lag distorts recent years.
- F01N exhaust treatment leads at 43.4% of records, ahead of engine control (31.6%) and separation/filtration methods (25.9%).
Filing growth compares 2021 (107 records) with 2024 (35) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 5,168 records in scope (CR5), not by the ranked leaders only.
What this patent set covers
This landscape tracks patent filings at the intersection of selective catalytic reduction, exhaust gas recirculation and engine NOx control with the operational problems that make marine and heavy-duty diesel deployments hard: urea dosing accuracy, sulphur poisoning of catalyst substrates, tier compliance thresholds, reactor placement within the exhaust train, low-load operation, and maintenance interval extension. The search string combines core abatement mechanisms with these constraint terms, so the set skews toward claims that address real-world durability and compliance rather than laboratory-scale catalyst chemistry alone.
5,168 published records fall inside the 2015 to 2026 window used here. Because publication trails filing by roughly 18 months, the most recent one to two years in any trend understate actual filing activity and should be read as provisional.
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Filing trend and technology composition
Two views of the same 5,168-record set: how filing volume has moved year on year, and which IPC subclasses carry the claims.
Filing trend: a sharp peak, then a real decline
Filings peaked in 2017 at 239 records. The only span the data supports treating as a completed trend is 2021 to 2024, where filings dropped 67%, from 107 to 35 records. Years after 2024 show low counts (down to 7 in 2026) purely because publication has not caught up with filing — they are not evidence the field has gone quiet.
Where the claims sit: exhaust treatment dominates
F01N (exhaust silencers and treatment) appears in 43.4% of records, the single densest subclass. F02D (engine control) and B01D (separation processes, including filtration) follow at 31.6% and 25.9%. Because records can carry multiple IPC codes, these figures are shares of the 5,168-record total, not a partition of it — a filing claiming both a catalyst reactor and its control logic counts in both F01N and F02D.
Shares are the percentage of the 5,168 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Marine Engine NOx Reduction with Eureka
This page is one run against one query. Ask Eureka your own question about marine engine nox reduction and every answer comes back with the patent numbers behind it.
Try EurekaA representative claim: ammonia-slip control during transitions
Method, apparatus, and system to control SCR catalyst ammonia slip during high-temperature transitions
Filed by Corning, the patent covers detecting an engine operation transition, increasing NOx delivered to the SCR catalyst, and decreasing reductant dose in a coordinated way so that ammonia slip is suppressed as catalyst temperature shifts. The system anticipates the temperature transition from an engine transition signal and adjusts both NOx and reductant flow to coincide with it, rather than reacting after the fact.Published 2015-08-04.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | WO2008132452A2 | Transition metal/zeolite SCR catalysts | 630 |
| 2 | US20180011052A1 | Silicon carbide based field effect gas sensor for high temperature applications | 391 |
| 3 | US10118119B2 | Radio frequency process sensing, control, and diagnostics network and system | 267 |
| 4 | US20040050037A1 | System and methods for improved emission control of internal combustion engines using pulsed fuel flow | 235 |
| 5 | US6882929B2 | NOx emission-control system using a virtual sensor | 229 |
| 6 | US20030101713A1 | System and methods for improved emission control of internal combustion engines | 198 |
| 7 | US6293246B1 | Spark-assist type self-ignition engine | 190 |
| 8 | US10287943B1 | System comprising duel-fuel and after treatment for heavy-heavy duty diesel (HHDD) engines | 181 |
| 9 | US6598402B2 | Exhaust gas recirculation type combined plant | 176 |
| 10 | US20080022658A1 | Method and Apparatus for Monitoring a Urea Injection System in an Exhaust Aftertreatment System | 159 |
Citation counts reflect influence within this searched corpus and favour older filings; they are not a measure of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the data actually supports
Three readings grounded strictly in the figures above — no extrapolation beyond what the evidence states.
A small group holds a third of the field
The leader alone accounts for 540 records, and the top ten combined reach 50.5% of all records in scope. For a new entrant, this means core SCR and EGR mechanisms are heavily claimed by a handful of established engine and catalyst manufacturers.
A real pullback, not a data artefact
This is the one multi-year span the dataset supports as complete. It follows a 2017 peak of 239 records, suggesting the initial wave of tier-compliance-driven filing has largely worked through the system.
Exhaust treatment hardware is the densest claim space
F01N filings outnumber engine-control (F02D, 31.6%) and separation-process (B01D, 25.9%) filings. A filer targeting reactor placement or substrate design is entering the most contested subclass in this set.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to marine engine nox reduction, with the prior art for and against each one.
Who is filing, and where activity has stopped
The ranked list covers 100 companies by record count. Several of the most active historical filers show zero filings in the latest tracked year, which given publication lag may mean either a genuine pause or filings still working through the pipeline.
One assignee well ahead of the rest
The top-ranked assignee holds 540 records against 223 at fifth place and 147 at tenth — a steep drop-off that marks this as a field with a dominant filer rather than a flat distribution.
Cross-entity filing is limited but pointed
The strongest co-assignee pairs link a parent automaker to its own subsidiaries or a catalyst maker to a university research partner, rather than showing broad cross-industry collaboration.
Top filers show no latest-year activity
Multiple assignees among the most active historical filers, including the field's largest filer, show zero recorded filings in the latest tracked year. Given the roughly 18-month publication lag, this is at least partly a reporting gap rather than a confirmed stop.
| Assignee | Recent year | YoY |
|---|---|---|
| Toyota Motor Corporation | 0 | — |
| Johnson Matthey PLC | 0 | -100% |
| GM Global Technology Operations LLC | 0 | — |
| BASF Corporation | 0 | — |
| Mazda Motor Corporation | 0 | — |
| Volvo Truck Corporation | 0 | — |
| BASF SE | 0 | — |
| Ford Global Technologies, LLC | 0 | — |
Where to take this analysis
The figures here describe the field at a high level. Turning them into a filing or freedom-to-operate decision means going claim-by-claim against the specific mechanism you plan to use.
Map your mechanism against the leaders' claim sets
If your approach touches SCR reactor placement, urea dosing control or EGR at low load, check it against the specific claims held by the top-ranked assignees before drafting.
Explore assignee claims in Eureka →Test the white-space chips against full claim text
The under-claimed branches flagged above are composition-based signals, not a guarantee of open space — confirm with full-text claim search.
Run a claim search in Eureka →Track the 2021–2024 decline forward as data fills in
Revisit filing-trend figures for 2025 and 2026 once publication catches up, rather than treating the current partial-year counts as a real slowdown.
Set up trend monitoring in Eureka →Common questions on this landscape
One assignee leads clearly with 540 records, well ahead of fifth place at 223 and tenth place at 147. The top five combined account for 34.5% of all 5,168 records in scope, and the top ten reach 50.5%, so filing activity is concentrated among a small group of established engine and catalyst manufacturers rather than spread evenly across the field. Anyone assessing freedom to operate should check the leader's portfolio first, since it dominates the ranked list by a wide margin.
The only span the data supports as a complete trend is 2021 to 2024, over which filings dropped 67%, from 107 to 35 records, following a 2017 peak of 239. Counts for 2025 and 2026 appear much lower still, but that reflects publication lag of roughly 18 months rather than an actual halt in filing. Treat any figure from the last one to two years as provisional until later publication catches up.
Exhaust treatment hardware, classified under F01N, appears in 43.4% of the 5,168 records, making it the single densest subclass. Engine control methods (F02D) follow at 31.6% and separation or filtration processes (B01D) at 25.9%, with internal-combustion engine design and fuel supply systems each around 20%. Because a single filing can carry several IPC codes, these percentages overlap rather than summing to a whole field.
Composition data points to comparatively thin coverage in areas like low-load SCR dosing control, sulphur-poisoning-resistant substrate design, and reactor placement solutions for compact exhaust trains, relative to the dense core mechanisms in F01N and F02D. These are composition-based signals from IPC distribution, not a confirmed absence of claims, so any filing decision should be checked against full claim text before relying on them. Under-claimed does not mean unclaimed.
US9097163B2, assigned to Corning and published in 2015, claims a method and system for controlling ammonia slip in an SCR catalyst specifically during high-temperature transitions, by detecting the transition event and coordinating a NOx increase with a reductant dose decrease timed to the temperature shift. It is a control-logic patent rather than a hardware or catalyst-chemistry patent, so it primarily constrains transition-management strategies rather than reactor design or substrate composition. Anyone building an SCR controller that anticipates temperature transitions should review its claim scope directly.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.