Prosecution Insights
Last updated: April 19, 2026
Application No. 17/911,845

ENERGY RECOVERY ASSEMBLY, FUEL CELL SYSTEM AND VEHICLE WITH ENERGY RECOVERY ASSEMBLY

Non-Final OA §103
Filed
Sep 15, 2022
Examiner
THOMAS, BRENT C
Art Unit
1724
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Airbus Defence and Space GmbH
OA Round
3 (Non-Final)
50%
Grant Probability
Moderate
3-4
OA Rounds
3y 10m
To Grant
76%
With Interview

Examiner Intelligence

Grants 50% of resolved cases
50%
Career Allow Rate
215 granted / 434 resolved
-15.5% vs TC avg
Strong +26% interview lift
Without
With
+26.4%
Interview Lift
resolved cases with interview
Typical timeline
3y 10m
Avg Prosecution
25 currently pending
Career history
459
Total Applications
across all art units

Statute-Specific Performance

§101
0.2%
-39.8% vs TC avg
§103
66.0%
+26.0% vs TC avg
§102
18.6%
-21.4% vs TC avg
§112
9.3%
-30.7% vs TC avg
Black line = Tech Center average estimate • Based on career data from 434 resolved cases

Office Action

§103
DETAILED ACTION Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Continued Examination Under 37 CFR 1.114 A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 1/19/2026 has been entered. Response to Arguments Applicant's arguments filed 12/05/2025 have been fully considered but they are not persuasive. The arguments are presented on pages 6-7 that Kelly and Knoop would not teach fuel flowing through an expansion machine in first and second modes. These arguments are not found persuasive due to the fact that Kelly teaches an expansion machine in fluid communication with a fuel cell and storage tank as seen in fig. 1 [0022-0024, fig 1]. Knoop teaches valves that may be configured to select fuel flow from a hydrogen source to a tank or directly to a fuel cell and teaches the hydrogen source, tank (fuel store 2) and expansion device (5) are connected [0031-0032]. Therefore, Kelly modified by Knoop would be capable of performing the claimed functions since there would be a fuel flow path through the expansion machine. Applicant’s arguments, see page 6, filed 12/05/2025, with respect to the rejection(s) of amended claim(s) 1 under Kelly and Knoop have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of Kelly, Knoop, and Ewan et al (US 5,346,778, hereafter Ewan). Ewan is relied upon for teaching the benefits of a valve located near a hydrogen tank as detailed in the claim rejections below. Claim Rejections - 35 USC § 103 The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action. Claim(s) 1-5, and 9-13 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kelley et al. (US 2010/0025232 A1, hereafter Kelley) in view of Knoop et al. (DE 10008823A1, hereafter Knoop), and further in view of Ewan et al (US 5,346,778, hereafter Ewan). With regard to claim 1, Kelley teaches an energy recovery assembly comprising: an electrolyzer configured to provide fuel and an oxidant (electrolyzer 12) [0016]; a fuel cell (fuel cell 54) configured to convert the fuel and the oxidant to electrical energy [0026]; a tank configured to store the fuel or the oxidant (storage tank 22 or 24) [0019, 0024]; a conduction pathway connecting the tank to the electrolyzer and the fuel cell (as seen in fig. 1) [0022-0024, fig 1]; an expansion machine (expansion engine 32) disposed in the conduction pathway and configure to expand a fluid flowing through the expansion machine and to obtain mechanical energy [0022-0024]; and wherein the fuel flows through the expansion machine (expansion engine 32) [0022-0024, fig. 1]. Kelley does not teach a valve arrangement configured to put the conduction pathway in a first conduction mode in which the fuel or the oxidant is guided to the tank or in a second conduction mode in which the fuel cell or the oxidant is guided to the fuel cell from the tank. However, in the same field of endeavor, Knoop teaches a valve configuration that allows for selecting fuel flow to a tank or directly to a fuel cell [0031-0032]. It would have been obvious to one of ordinary skill in the art at the time the invention was made to use the valve arrangement of Knoop with the energy recovery assembly of Kelly for the benefit of allowing for rapid reaction to peak loads or low emission operation of the fuel cell [Knoop 0035]. Kelly does not explicitly teach the location of the valve arrangement. However, in the same field of endeavor, Ewan teaches a valve (57) located adjacent to a hydrogen tank (storage bottle 4) [col. 6 lines 1-6, col. 7 lines 25-38, fig. 1]. It would have been obvious to one of ordinary skill in the art to use the valve location adjacent to a hydrogen storage tank of Ewan with the assembly of modified Kelly for the benefit of regulating output from the tank to allow a fuel cell to use stored hydrogen or generated hydrogen [Kelly col. 7 lines 25-38]. When used with the assembly of Kelly the valve would be located between the expansion machine and tank since it is taught by Ewan to be adjacent to the tank. With regard to claims 2 and 4, Kelley does not teach the claimed valve arrangement. However, in the same field of endeavor, Knoop teaches a multiway valve (capable of selecting between two paths) configuration that allows for selecting fuel flow from a hydrogen source to a tank or directly to a fuel cell and teaches the hydrogen source, tank (fuel store 2) and expansion device (5) are connected [0031-0032]. It would have been obvious to one of ordinary skill in the art at the time the invention was made to use the valve arrangement of Knoop with the energy recovery assembly of Kelly for the benefit of allowing for rapid reaction to peak loads or low emission operation of the fuel cell [Knoop 0035]. When used with the energy recovery assembly of Kelly the valve arrangement of Knoop would be connected to the hydrogen source (electrolyzer 12) of Kelly. With regard to claim 3, Kelley does not explicitly teach a shutoff valve in an outlet conduit of the electrolyzer. However, in the same field of endeavor, Ewan teaches an electrolyzer with a shutoff valve (flow control valves 98, 99, which would be capable of altering a flow cross section) located in electrolyzer outlets [col. 7 lines 50-59]. It would have been obvious to one of ordinary skill in the art at the time the invention was made to use the valves of Ewan with the electrolyzer of modified Kelley for the benefit of maintaining high pressure in the electrolyzer during time it is not powered [Ewan col. 7 lines 50-59]. With regard to claim 5, Kelly does not teach the claimed valve arrangement. However, in the same field of endeavor, Knoop teaches a multiway valve (capable of selecting between two paths) configuration that allows for selecting fuel flow from a hydrogen source to a tank or directly to a fuel cell and teaches the tank (fuel store 2) and outlet of the expansion device (5) are connected [0031-0032]. It would have been obvious to one of ordinary skill in the art at the time the invention was made to use the valve arrangement of Knoop with the energy recovery assembly of Kelly for the benefit of allowing for rapid reaction to peak loads or low emission operation of the fuel cell [Knoop 0035]. Modified Kelly would not explicitly teach multiple multiway valves, however this would be an obvious variant to one of ordinary skill in the art since it would only require a duplication of parts. See MPEP 2144.04 VI. With regard to claim 9, Kelly teaches the expansion machine (expansion engine) is configured to convert the mechanical energy to electrical energy (via electrical generator) [0022]. With regard to claim 10, Kelly teaches a generator coupled to the expansion machine (expansion engine) [0022]. With regard to claim 11, Kelly teaches a high pressure electrolyzer that can produce hydrogen and oxygen at up to 10,000 psi (equivalent to a range of 0 to 689 bar) [0017] and would therefore be capable of operating at the claimed pressures. With regard to claim 12, Kelley teaches a water tank [0018] but does not explicitly teach it is capable of collecting and storing water formed in the fuel cell. However, in the same field of endeavor, Ewan teaches collecting byproduct water from the fuel cell in a tank [col. 4 lines 5-21]. It would have been obvious to one of ordinary skill in the art at the time the invention was made to use the water tank connected to a fuel cell of Ewan with the energy recovery assembly of modified Kelley for the benefit of being able to use byproduct water from the fuel cell for electrolysis or cooling [Ewan col. 4 lines 5-21]. With regard to claim 13, Kelly teaches a vehicle comprising the energy recovery assembly [0008]. Claim(s) 6-8 and 14-15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kelley, Knoop, and Ewan as applied to claims 1-5, and 9-13 above, and further in view of Endoh et al (US 2004/0031384 A1, hereafter Endoh). With regard to claims 6-8 and 14-15, Kelley teaches an expansion machine (expansion engine) [0022-0024] but does not teach the claimed details of the expansion machine. However, in the same field of endeavor, Endoh teaches an expansion machine that is a rotary flow machine (claim 6) [0010, 0035, 0077] with a tooth (vanes in vane piston units, claim 7) arrangement [0059, fig. 4] and is a rotary piston expansion machine (reciprocal rotating pistons, claim 14) [0009]. Endoh further teaches the tooth arrangement (vane piston units) comprise a rotatable first section (cylinder member 39) and a second section with an expansion space between (gaps between inner wall of cylinder 39 and piston 41 as seen in fig. 2 and fig. 4, claim 8) [0040-0042, fig. 2, fig. 4]. Endoh further teaches that the rotary flow machine comprises seven teeth (incudes a seventh vane piston unit, claim 15) [0059]. It would have been obvious to one of ordinary skill in the art at the time the invention was made to use the rotary flow machine of Endoh as the expansion machine of Kelley for the benefit of an expansion machine with enhanced durability [Endoh 0009, 0083]. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to BRENT C THOMAS whose telephone number is (571)270-7737. The examiner can normally be reached Flexible schedule, typical hours 11-7 M-F. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Miriam Stagg can be reached at (571)270-5256. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /BRENT C THOMAS/Examiner, Art Unit 1724 /STEWART A FRASER/Primary Examiner, Art Unit 1724
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Prosecution Timeline

Sep 15, 2022
Application Filed
Apr 30, 2025
Non-Final Rejection — §103
Aug 01, 2025
Response Filed
Oct 22, 2025
Final Rejection — §103
Dec 05, 2025
Response after Non-Final Action
Jan 19, 2026
Request for Continued Examination
Jan 26, 2026
Response after Non-Final Action
Feb 21, 2026
Non-Final Rejection — §103 (current)

Precedent Cases

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
50%
Grant Probability
76%
With Interview (+26.4%)
3y 10m
Median Time to Grant
High
PTA Risk
Based on 434 resolved cases by this examiner. Grant probability derived from career allow rate.

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