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Run your analysis now →Filing growth compares 2021 (1 records) with 2024 (6) — 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 35 records in scope (CR5), not by the ranked leaders only.
Hydrogen direct injection system design sits at the intersection of fuel delivery hardware and combustion control: injector sealing under cryogenic or high-pressure hydrogen, material embrittlement resistance, injection pressure and rate shaping, mixing quality inside the cylinder, and lubrication of moving parts that no longer benefit from a liquid fuel film. This search scopes 35 published records filed against that combination of terms between 2015 and the 2026-07-31 cut-off, ranked across 19 assignees.
Because publication trails filing by roughly 18 months, the most recent years in the trend understate real activity; 2024 is the most recent year that can be read as complete, and the record set already shows where claim density has built up and where it has not.
Pick a task. Every answer cites the patents behind it.
Two views of the same 35 records: how filing activity moved year over year, and which IPC subclasses the claims fall under.
Filings were negligible before 2021, then rose from 1 that year to 6 in 2024 (+500%), peaking at 19 in 2023. 2025 and 2026 figures are still filling in as publications catch up with filing dates, so read the tail of the curve as incomplete rather than declining.
F02M (fuel supply and carburettors) appears on 65.7% of the 35 records, with F02B (internal-combustion engines) on 45.7% and F02D (engine control) on 42.9%. Smaller shares in C01B, F01M, F01N, B01D and F01P mark adjacent branches — material chemistry, lubrication, exhaust treatment, filtration and cooling — that are claimed far less often; since records can carry multiple classes these shares sum to more than 100%.
Shares are the percentage of the 35 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
This page is one run against one query. Ask Eureka your own question about hydrogen direct injection system design and every answer comes back with the patent numbers behind it.
Try EurekaAn embodiment hydrogen direct injection system for an internal combustion engine of a motor vehicle includes a fuel line and a fuel injector configured to inject hydrogen fuel into a combustion chamber of the internal combustion engine, wherein the fuel injector is configured to receive the hydrogen fuel via the fuel line and to receive water via the fuel line, and wherein the water is configured to lubricate the fuel injector.Filed by Hyundai Motor Company, published 2024-11-14. It claims water delivered through the fuel line itself as the lubrication mechanism for the injector, rather than a separate lubricant circuit.

| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20100012090A1 | Hydrogen delivery system and method for an internal combustion engine | 39 |
| 2 | FR2262195A1 | IC engine with strata charge - hydrogen is injected into ante chamber and ignited | 8 |
| 3 | WO2023137515A1 | Hydrogen-diesel direct injection dual-fuel system for internal combustion engines | 7 |
| 4 | CN219865274U | 一种自润滑高效混合冷型氢喷射器及直喷氢内燃机 | 3 |
| 5 | CN114576028A | 一种掺氢的缸内直喷氨发动机及其控制方法 | 3 |
| 6 | CN116927982A | 一种氢内燃机燃料低压双级混合装置及控制方法 | 2 |
| 7 | CN117722286A | 一种氢燃料发动机及其滚流调节方法 | 1 |
| 8 | US20240376852A1 | Hydrogen Direct Injection System and Method for Lubricating a Fuel Injector of a Hydrogen Direct Injection Sy… | 1 |
| 9 | US20250116238A1 | Hydrogen-diesel direct injection dual-fuel system for internal combustion engines | 1 |
| 10 | FR2262195B1 | FR2262195B1 | 1 |
Citation counts inside a searched corpus favour older filings; treat them as a signal of influence on the field rather than of current technical importance.
Patent titles are shown in the language they were filed in, not translated, so that each record stays verifiable against the original filing — a translated title will not match in Eureka or in any national register. Each row carries its publication number; clicking a row searches Eureka by that number.
When you want the answer in the next five minutes.
The agent works the prompt against patents and technical literature, citing every source.
Run your analysis now →When it has to run inside your own pipeline.
Patent search, landscape analysis and assignee resolution as MCP tools. Drop them into any agent framework, or call REST directly.
Browse MCP servers →Three read-outs from the dataset that matter more than the raw counts.
With the top 5 assignees covering 28 of 35 records and the top 10 covering all of them, a new entrant is not filing into open ground — it is filing alongside a small set of established players who between them have staked out most of the documented claim space.
Filings rose from 1 in 2021 to 6 in 2024, with a peak of 19 in the 2023 cohort. Because 2025-2026 publications are still arriving, the apparent slowdown after 2023 should not be read as the technology cooling off.
F02M (fuel supply and carburettors) is the most heavily claimed subclass, ahead of F02B combustion architecture and F02D engine control. Lubrication, filtration and cooling classes each sit under 10% of records — thinner ground for a fresh claim.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to hydrogen direct injection system design, with the prior art for and against each one.
Automakers and a handful of research institutes dominate the ranked list; the co-assignee pattern points to at least one active OEM partnership.
The leading assignee holds 8 of the 35 records in scope, roughly a quarter of the dataset on its own, with the next-ranked filers spread across a shorter tail down to single-digit and single-filing counts.
The strongest co-assignee pairing in the dataset links Kia Corporation and Hyundai Motor Co Ltd across 7 records, consistent with a shared OEM group R&D pipeline rather than incidental overlap.
Beyond the leading names, the ranking thins quickly to single- and double-digit holders, including research institutes and component specialists, suggesting the field is still attracting new entrants even as concentration sits high at the top.
| Assignee | Recent year | YoY |
|---|---|---|
| NewSouth Innovations Pty Ltd | 0 | — |
| Kia Corporation | 0 | — |
| Hyundai Motor Co Ltd | 0 | — |
| RENAULT & PEUGEOT | 0 | — |
| Yamaha Motor Co Ltd | 0 | — |
| Dumarey Automotive Italia SpA | 0 | — |
| Huazhong University of Science and Technology | 0 | — |
| Great Wall Motor Company Limited | 0 | — |
The dataset points to a field with a short list of established filers and several thinner branches still open for a well-drafted claim.
Cross-reference the under-claimed IPC branches above — lubrication, filtration, cooling — against your own component roadmap before drafting, since these are the areas with the fewest existing claims to design around.
Explore in EurekaThe Kia-Hyundai co-assignee pairing suggests joint R&D structures matter here; tracking which assignees start filing jointly is an early signal of where the next concentration will form.
Track assignees in EurekaThe ranked list of 19 assignees shows a clear leader with 8 of the 35 records in scope, roughly a quarter of the field on its own. The next four assignees combined bring the top 5 to 80.0% of all records, so the field is concentrated among a small group of automakers and research institutes rather than spread evenly. Anyone assessing freedom to operate should start by reviewing that leader's full portfolio before looking at the longer tail.
Filings grew sharply from 1 in 2021 to 6 in 2024, a +500% increase, with the dataset's peak year at 19 filings in 2023. Counts for 2025 and 2026 appear lower only because patent publication typically lags filing by about 18 months, so those years are still filling in rather than showing an actual slowdown. Treat 2024 as the most recent year that reflects real activity.
Fuel supply and carburettor claims, classified under IPC F02M, appear on 65.7% of the 35 records, making it the densest area by a clear margin. Internal-combustion engine architecture (F02B) and engine control (F02D) follow at 45.7% and 42.9% respectively. Lubrication, filtration, exhaust treatment and cooling classes each sit at or below 8.6%, marking them as comparatively open ground for new claims.
US20240376852A1 describes a hydrogen direct injection system where water is delivered through the same fuel line as the hydrogen to lubricate the fuel injector, filed by Hyundai Motor Company and published 2024-11-14. The specific mechanism at issue is using the existing fuel line as the delivery path for lubricant rather than adding a separate lubrication circuit. Anyone designing an injector lubrication approach that also routes fluid through the fuel line should review this claim scope closely.
The thinner IPC branches in this dataset — engine lubrication (F01M), exhaust treatment (F01N), separation and filtration (B01D) and engine cooling (F01P) — each cover 8.6% or less of the 35 records, well below the fuel-supply and combustion classes. That gap suggests injector lubrication circuits, upstream hydrogen filtration, and cooling integration are less crowded than core injection-pressure and mixing claims. A first claim in one of these branches has more room to establish a clean position before the field concentrates further.
Go past this page: query the whole hydrogen direct injection system design corpus yourself, in your own scope.
Every answer comes back with patent numbers you can open.
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.
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