Combustion & Emissions Control Patents: Who Leads, Where Gaps Are 2026
- Concentration is real but not total. the top 5 filers hold 31.8% of all 1,166 records in scope, and the top 10 hold 42.2% — leaving well over half the field to a long tail of single- and few-filing entrants.
- Engine control and fuel supply dominate the claim map. F02D (engine control) and F02M (fuel supply & carburettors) each cover roughly a fifth of records, well ahead of exhaust treatment and electric-propulsion classes.
- Filing has cooled from its 2017 peak. output ran from 86 records in 2017 down to a documented -45% contraction between 2021 (40) and 2024 (22), the last year publication lag lets us read cleanly.
Filing growth compares 2021 (40 records) with 2024 (22) — 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 1,166 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This dataset spans 1,166 published records filed between 2015 and 2026 that combine combustion or emissions-control subject matter with a fluid-system or sensor mechanism claim — engine control loops, fuel-pressure circuits, exhaust treatment devices and the rotor or actuator hardware that drives them. The search string ties classic emissions-control language to fluid actuator, pressure circuit and emission-sensor terms, so the corpus favours systems-level claims over pure chemistry or catalyst-formulation filings.
Because publication trails filing by around 18 months, any apparent drop-off in the most recent one to two years reflects reporting lag rather than a real stop in R&D activity. Family-level counting, used throughout this ranking, also reduces the distortion from assignees who multiply filings by jurisdiction or continuation.
Filing trend and technology composition
Two views of the same 1,166-record corpus: how filing volume has moved year over year, and how the underlying technology splits across IPC subclasses.
Filing trend: a 2017 peak, then a documented contraction
Annual output peaked at 86 records in 2017. The clean comparison window shows filings falling from 40 in 2021 to 22 in 2024, a -45% move over three years; 2025 and 2026 figures are still filling in under publication lag and should not be read as a continued decline.
IPC composition: engine control and fuel supply lead
F02D (engine control) leads at 20.0% of the 1,166 records, closely followed by F02M (fuel supply & carburettors) at 18.2% and F02B (internal-combustion engines) at 16.0%. Exhaust treatment (F01N, 9.9%) and the electric-propulsion classes (B60L, 5.7%) sit well behind, and because records often carry multiple classes these shares sum to more than 100%.
Shares are the percentage of the 1,166 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Combustion & Emissions Control Patent Landscape with Eureka
This page is one run against one query. Ask Eureka your own question about combustion & emissions control patent landscape and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative filing and most-cited prior art
US5012641A — Emissions control system for use in conjunction with an IC engine primary emissions control system
An apparatus retrofit onto a tailpipe of an internal combustion engine that works alongside the engine's primary emissions control system to improve overall performance. It comprises a housing with an inlet connected to the tailpipe, an exhaust gas treatment device in fluid communication with that inlet, and a fan powered by an engine-driven motor that is controlled according to exhaust manifold pressure, so as to manage overall fluid pressure drop through the system.Filed as a retrofit device rather than an OEM system, which shapes how narrowly its claims can be read against integrated designs.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20120227389A1 | Reciprocating machine & other devices | 239 |
| 2 | US20040219079A1 | Trifluid reactor | 238 |
| 3 | US6882929B2 | NOx emission-control system using a virtual sensor | 229 |
| 4 | US7523603B2 | Trifluid reactor | 223 |
| 5 | US5678521A | System and methods for electronic control of an accumulator fuel system | 201 |
| 6 | US5787864A | Hydrogen enriched natural gas as a motor fuel with variable air fuel ratio and fuel mixture ratio control | 198 |
| 7 | US20080141921A1 | Reciprocating devices | 197 |
| 8 | US20130158838A1 | Device to Increase Fuel Economy | 173 |
| 9 | US20070234702A1 | Thermodynamic cycles with thermal diluent | 148 |
| 10 | US6364602B1 | Method of air-flow measurement and active operating limit line management for compressor surge avoidance | 144 |
Citation counts are drawn from a search-scoped corpus and skew toward older filings; treat them as a signal of influence on later filers, 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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Read together, the concentration, class mix and citation pattern point to where claim space is occupied and where it is thin.
The top of the field is dense, not closed
Five assignees hold 31.8% of all records and ten hold 42.2%, so a majority of the corpus still sits with entities filing only a handful of times each. That long tail is where freedom-to-operate searches most often turn up surprises, because it is under-indexed relative to the leaders.
Engine control claims crowd the centre of the map
F02D and F02M together touch roughly a third of the corpus between them, meaning control-loop and fuel-delivery claims are the most contested ground. Exhaust treatment (F01N) and separation processes (B01D) are filed far less often, which is worth checking before assuming that space is settled.
Volume has cooled from its 2017 high
Output peaked at 86 records in 2017 and had fallen to 22 by 2024, a documented -45% move over that window. That is a real contraction in the clean data, not an artefact of publication lag, and it suggests filers are consolidating around fewer, more defensible applications rather than broadening coverage.
Older reciprocating-machine and sensor patents still anchor the field
The most-cited records in this corpus date from well before the current filing window and concentrate on reciprocating-machine design and virtual NOx sensing. Their citation counts reflect how much later work built on them, not how relevant they are to a 2026 filing decision.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to combustion & emissions control patent landscape, with the prior art for and against each one.
Who is filing, and where the gaps sit
The ranked leaders are automotive and industrial engine makers with broad, multi-year filing programmes; behind them sits a long tail of single-filing entrants, from individual inventors to specialised component makers.
One filer sits well ahead of the field
The leading assignee's 167 records is more than five times the fifth-place total of 31, a gap that marks a genuinely dominant filer rather than a cluster of near-equal peers.
The drop-off past the leader is gradual
Fifth place holds 31 records and tenth place 19 — a steady taper rather than a cliff, consistent with several engine and component makers running comparable, sustained filing programmes rather than one company cornering a niche.
Co-filing is rare and concentrated
Only 10 co-assignee pairs appear in the dataset, and the strongest links are repeated pairings between the same two parties rather than a broad web of joint ventures. Most of the field files independently.
| Assignee | Recent year | YoY |
|---|---|---|
| Ford Global Technologies, LLC | 0 | — |
| Caterpillar Inc. | 0 | — |
| Owens Corning Intellectual Capital, LLC | 0 | — |
| Cummins Inc. | 0 | — |
| HINDERKS MITJA VICTOR | 0 | — |
| Shaw Development, LLC | 0 | — |
| KOBAYASHI TAKAITSU | 0 | — |
| General Electric Company | 0 | — |
Where to take this analysis
The dataset points to a field with a dominant leader, a wide mid-field, and technical branches that remain thinly claimed. The next steps depend on whether the goal is freedom-to-operate, licensing, or identifying where to file next.
Run a freedom-to-operate check against the long tail
With 57.8% of records held outside the top 10 filers, a freedom-to-operate search needs to cover single- and few-filing entrants, not just the ranked leaders.
Explore assignees in Eureka →Test claim language against the under-claimed branches
Virtual sensor calibration and rotor-dynamics-linked pressure control show thinner filing density than engine-control claims — worth drafting against before the space fills in.
Draft claims in Eureka →Common questions on combustion and emissions control patents
One assignee leads the ranked field with 167 records, more than five times the fifth-place total of 31. Behind that leader the drop-off is gradual rather than sharp — tenth place still holds 19 records — which points to several established engine and component makers running sustained, comparable filing programmes. The top 10 filers combined account for 42.2% of all 1,166 records in scope, leaving the majority of the corpus to a long tail of smaller filers.
Filing peaked at 86 records in 2017 and has since declined; the clean comparison window shows a -45% drop from 40 records in 2021 to 22 in 2024. Because publication lags filing by roughly 18 months, 2025 and 2026 figures are still incomplete and should not be read as evidence of a further slowdown. Taken together, the trend through 2024 shows a real contraction from the 2017 high rather than a plateau.
Engine control (F02D) and fuel supply and carburettors (F02M) are the two densest classes, each covering roughly a fifth of the 1,166 records in scope. Internal-combustion engine design (F02B) follows close behind at 16.0%. Exhaust treatment, separation processes and electric-vehicle propulsion classes are filed far less often, which is a useful signal for where claim space is comparatively open.
The under-claimed branches sit adjacent to the dense engine-control and fuel-supply clusters rather than far from them: virtual sensor calibration, rotor-dynamics-linked fuel pressure control, and retrofit exhaust-fan pressure regulation all show comparatively thin filing density relative to core engine control claims. A first claim in these areas would face a thinner prior-art field, though that also means fewer established validity precedents to lean on. High density elsewhere signals occupied claim space, not that the underlying technology is exhausted.
A high citation count inside this search-scoped corpus indicates that later filers repeatedly built on or referenced that disclosure, which is a signal of influence rather than of current commercial dominance. Citation counts also skew toward older records simply because they have had more years to accumulate citations. For a 1991 filing like US5012641A, the practical question is whether its specific retrofit-device claims still read onto current integrated designs, which requires a claim-by-claim comparison rather than relying on the citation count alone.
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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.