Acoustic volume and insulation in hot-end of exhaust systems
US-2021262374-A1 · Aug 26, 2021 · US
having sound-absorbing materials in resonance chambers
having sound-absorbing materials in resonance chambers · Cooperative Patent Classification (CPC)
Engines, pumps, lighting, heating, and mechanical systems.
Related technology areas
Mapped technology topics for this CPC code.
| Metric | Value |
|---|---|
| CPC code | F01N1/04 |
| Official title | having sound-absorbing materials in resonance chambers |
| Display label | having sound-absorbing materials in resonance chambers |
| Total patents | 89 |
Filing trend
Year-over-year patent counts classified under this CPC code.
Filing activity over the last five years is declining.
| Year | Patents |
|---|---|
| 2015 | 7 |
| 2016 | 7 |
| 2017 | 13 |
| 2018 | 5 |
| 2019 | 12 |
| 2020 | 13 |
| 2021 | 7 |
| 2022 | 8 |
| 2023 | 6 |
| 2024 | 7 |
| 2025 | 4 |
Representative patents
Representative publications under this CPC code from precomputed stats, or recent filings when stats are unavailable.
Muffler
US-2021246818-A1 · Aug 12, 2021 · US
Methods of and systems for constraining fibrous material during filling operation
US-10883399-B2 · Jan 5, 2021 · US
Apparatus for discharging water in exhaust fluid and silencer for fuel cell vehicle
US-10865673-B2 · Dec 15, 2020 · US
Exhaust heat recovery system
US-2020378285-A1 · Dec 3, 2020 · US
Acoustic absorber for fan noise reduction
US-2020284174-A1 · Sep 10, 2020 · US
Exhaust system as well as motor vehicle with an exhaust system
US-2020256227-A1 · Aug 13, 2020 · US
Acoustic damper for gas turbine combustors with orthogonal slots
US-2020232357-A1 · Jul 23, 2020 · US
Apparatus for discharging water in exhaust fluid and silencer for fuel cell vehicle
US-2020232358-A1 · Jul 23, 2020 · US
Exhaust device
US-2020182111-A1 · Jun 11, 2020 · US
Apparatus for discharging water in exhaust fluid and silencer for fuel cell vehicle
US-10648379-B2 · May 12, 2020 · US
Vacuum Cleaner and Electric Motor Module Thereof
US-2020141295-A1 · May 7, 2020 · US
Silencer for an exhaust gas system of a motor vehicle and motor vehicle with a silencer
US-2020088077-A1 · Mar 19, 2020 · US
Exhaust Device With Noise Suppression System
US-2020088078-A1 · Mar 19, 2020 · US
Sound-absorbing material
US-2020010028-A1 · Jan 9, 2020 · US
Muffler
US-2020003093-A1 · Jan 2, 2020 · US
Valve assembly
US-10518632-B2 · Dec 31, 2019 · US
Muffler for an exhaust system of an internal combustion engine
US-2019368396-A1 · Dec 5, 2019 · US
Methods of and systems for constraining fibrous material during filling operation
US-2019345856-A1 · Nov 14, 2019 · US
Turbocharger with a wastegate noise reduction device
US-10473121-B2 · Nov 12, 2019 · US
Frequently asked questions
Answers are generated from the same data shown on this page.
- What is CPC F01N1/04?
- CPC F01N1/04 is the Cooperative Patent Classification code for “having sound-absorbing materials in resonance chambers.”
- How many patents are filed under CPC F01N1/04 (having sound-absorbing materials in resonance chambers)?
- Our database includes 89 publications tagged with this CPC code.
- Is patent activity under CPC F01N1/04 growing?
- Publication counts under this code: 7 in 2024 vs 4 in 2025 (latest complete years).