CPC technology class · F23

F23N - Regulating Or Controlling Combustion

Regulating or controlling combustion. 1,763 US utility patents granted 2015–2025, with the leading assignees and year-by-year grant trajectory.

Compiled by PlainPatent · May 15, 2026

1,763
US patents granted: #3/12
in F23: 11.5%
F23 class share: -8%
5-yr velocity

The verdict

According to USPTO PatentsView, Regulating Or Controlling Combustion ranks #385 of 670 CPC technology areas - 1,763 US patents granted since 2015, with recorded grant volume down 8% over five years.

#385
of 670 CPC technology areas: 1,763
US patents granted, 2015–2025: General Electric
leading assignee (89): -8%
grant velocity, last 5 yrs

How F23N's grant cadence moved

Between 2020–2024, F23N recorded 772 grants versus 837 in 2015–2019 (-8% equal-window velocity). Across complete years, output peaked in 2019 at 196 grants and bottomed in 2024 at 127 (+54% peak-over-trough). Lead assignee Clearsign Combustion Corporation holds 2.3% of the class ; the top three share 5.9%.

Leaderboard read

F23N concentration, lead at 2.3%

Clearsign Combustion Corporation leads this historical grant record at 2.3% of F23N - us corporation assignees hold 56% of class grants (447 of 792). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.

Leader's share: 2.3%
Top three share: 5.9%
Lead over #2: 2

Where F23N sits inside F23

Among 12 subclasses in F23 (Combustion APPARATUS; Combustion Processes), F23N ranks #3 and holds 11.5% of the parent class's 15,279 recorded grants. Sibling chips below are the other subclasses in the same parent class, not the nationwide volume/lead-share peers further down.

F23R 4,138 F23D 2,623 F23C 1,571 F23J 1,082 F23G 1,073 F23L 922 F23K 754 F23M 568

Rising assignees active in F23N

Company-wide grant multiples (2022–2024 vs 2019–2021) among assignees with ≥5 patents in this subclass. Growth is company-wide; class patent counts are subclass-specific.

#1 Copeland Comfort Control LP 17x 0 → 17 company-wide · 10 in F23N
#2 Rheem Manufacturing Company 2.26x 80 → 181 company-wide · 23 in F23N
#3 Truma Geraetetechnik GMBH & Co. KG 2.13x 8 → 17 company-wide · 5 in F23N
#4 EBM Papst Landshut GmbH 2.00x 4 → 8 company-wide · 6 in F23N
#5 Ludela Technologies LLC 2.00x 2 → 4 company-wide · 6 in F23N

F23N grants by year, peak 2019 (196)

US utility-patent grants per year in F23N, 2015–2025 - recent five years are down 8% versus 2015–2019.

Clearsign Combustion

40
Haier Us Appliance…

38
Emerson Electric

26
Midea Group

23
Rheem Manufacturing

23
Kyungdong Navien

20
Rinnai

20
Grand Mate

20
Weber-stephen Products

19
EberspÄCher Climate…

18
Copreci S Coop

16
Azbil

15

What this shows General Electric is the most active filer in F23N, holding 89 of the 1,763 patents in this class. Concentration at the top signals how contestable this technology area is for new entrants.

View data table

Top patent holders in CPC subclass F23N
Rank	Company	Patents in F23N
#1	Clearsign Combustion Corporation	40
#2	Haier US Appliance Solutions, Inc.	38
#3	Emerson Electric Co.	26
#4	Midea Group Co., Ltd.	23
#5	Rheem Manufacturing Company	23
#6	Kyungdong Navien Co., Ltd.	20
#7	Rinnai Corporation	20
#8	Grand Mate Co., Ltd.	20
#9	Weber-Stephen Products LLC	19
#10	EBERSPÄCHER Climate Control Systems GMBH	18
#11	Copreci, S.COOP.	16
#12	Azbil Corporation	15
#13	ClearSign Technologies Corporation	15
#14	Noritz Corporation	14
#15	Ener-Core Power, Inc.	12
#16	Ademco Inc.	11
#17	SIT S.P.A.	11
#18	Delavan Inc.	10
#19	A. O. Smith Corporation	10
#20	Copeland Comfort Control LP	10

Footprint here vs. claim strategy

Each dot is a leading F23N assignee, placed by how many patents it holds in this class (horizontal) against its company-wide average claims per patent (vertical) - a read on whether the class is led by broad-but-shallow filers or focused deep-claim players.

Top 14 F23N assignees by class footprint. Bubble size = patents in F23N. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Classes near F23N's 1,763-grant footprint

Nationwide nearest neighbors for F23N (#385 of 670 by volume ; lead share 5.0%) - not the F23 parent-class siblings above.

Nearest by grant volume

F16N 1,760 B44C 1,788 A01F 1,791 A43C 1,793

Nearest by lead-assignee share

B26F 5.0% B63C 5.1% C10M 5.0% B07C 5.0%

Questions about F23N

Which company holds the most patents in F23N?

General Electric Company leads F23N with 89 patents (2.3% of the subclass). By PatentsView assignee type, us corporations account for 56% of class grants.

Which F23N assignees grew fastest recently?

Among assignees with ≥5 grants in F23N, Copeland Comfort Control LP shows the highest company-wide grant multiple (17x: 0 grants in 2019–2021 → 17 in 2022–2024) while holding 10 patents in this subclass. Growth is company-wide, not class-only.

How does F23N compare inside parent class F23?

Inside F23 (Combustion APPARATUS; Combustion Processes), F23N ranks #3 of 12 subclasses by grant volume and holds 11.5% of the parent class total. The largest sibling is F23R (4,138 grants).

What to do with this data

F23N in context - here's where to go next.

Clearsign Combustion Corporation leads F23N with 40 grants in this class. See full portfolio
F23N ranks #385 of 670 by grant volume among all tracked CPC technology areas. See the ranking
Inside parent class F23, the largest sibling subclass is F23R with 4,138 grants. Explore F23R

Figures reflect USPTO PatentsView grant data through 2026-05-15; pending applications not yet granted are not counted.

Methodology - F23N figures are USPTO PatentsView granted-utility totals for this subclass (1,763 grants in the tracked window).

Every figure on PlainPatent is rendered directly from USPTO source data, no number is typed in by an editor. This page draws directly on USPTO source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.