Prosecution Insights
Last updated: April 19, 2026
Application No. 18/520,631

MACHINE COOLING CIRCUIT OF AN ELECTRIC MACHINE, OVERALL COOLING CIRCUIT OF A MOTOR VEHICLE, AND MOTOR VEHICLE

Final Rejection §103§112
Filed
Nov 28, 2023
Examiner
SUBRAMANIAN, VISWANATHAN
Art Unit
2834
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
DR. ING. H.C. F. PORSCHE AG
OA Round
2 (Final)
80%
Grant Probability
Favorable
3-4
OA Rounds
2y 9m
To Grant
99%
With Interview

Examiner Intelligence

Grants 80% — above average
80%
Career Allow Rate
159 granted / 198 resolved
+12.3% vs TC avg
Strong +23% interview lift
Without
With
+22.9%
Interview Lift
resolved cases with interview
Typical timeline
2y 9m
Avg Prosecution
40 currently pending
Career history
238
Total Applications
across all art units

Statute-Specific Performance

§101
0.9%
-39.1% vs TC avg
§103
54.8%
+14.8% vs TC avg
§102
30.0%
-10.0% vs TC avg
§112
13.6%
-26.4% vs TC avg
Black line = Tech Center average estimate • Based on career data from 198 resolved cases

Office Action

§103 §112
DETAILED ACTION This communication is in response to the Applicant filing on 12.22.25. Claims 1-19 are pending and have been examined. 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 . Response to Arguments and Amendments The Applicant has made amendments to the independent claim 1 and its dependents 5, 6,11,13 and added new claims 15-19 which will be examined below. Claim objection relative to claims 6,11,13 are withdrawn in light of amendments. Claim 6 rejection under 35 U.S.C 112(b) is withdrawn in light of amendments. With respect to 35 U.S.C 102 and 103 rejections, the Applicant provides arguments to which the Examiner will respond accordingly: Applicant Argument 1: In contrast, Lange merely describes a coolant expansion tank 46 that "serves to continuously vent [a] closed engine coolant circuit and to compensate for the change in volume of [] coolant." See Detailed Action, page 5. It is respectfully submitted, however, that an expansion tank that is continuously vented is not force-loaded or pressure-loaded. Nor does force- or pressure-loading cause separation of entrained air in a vented expansion tank. Examiner Response 1: Examiner will consider above argument specifically that force loading and pressure loading is not same as force due to gravity or atmospheric pressure. Examiner would like to record that out of cited Para 0018,0023,0047, both 0018 and 0047 discusses impediment to air bubble formation due to pressure which is different from separation of air bubble(which implies air bubbles already formed and then being removed). In light of argument and cited paragraphs, Examiner will interpret using pressure as a way to impede air bubble formation. Claim Rejections - 35 USC § 112 Claim 17 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention. Claim 17 recites the limitations “the compensating reservoir is arranged remotely of heat sources” . “relative to other components…” is not being considered as they are not recited in cited Para 0050 or any other part of specification. The term “remotely” in claim 17 is a relative term which renders the claim indefinite. The term “remotely” is not defined by the claim (original specification does not support for amendment “relative to other components”), the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. Claim Rejections - 35 USC § 103 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention. The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. Claim 1-4, 7-10, 12-14,18 are rejected under 35 U.S.C. 103 as being unpatentable over Lange in view of Lenz et al(DE102020114381A1 English translation), hereinafter Lenz. Regarding Claim 1, Lange discloses (Fig 1) a machine cooling circuit (40) of an electric machine (12) of a motor vehicle [Abstract], comprising: a coolant [0027 discloses coolant] adapted to flow through the machine cooling circuit; and a compensating reservoir (46), wherein the electric machine is a directly cooled electric machine [0017 discloses “The heat is generated in particular at the stator windings, wherein the stator windings are preferably directly surrounded by the coolant, in particular a dielectric coolant, and are thereby cooled], which is accommodated in the machine cooling circuit such that the coolant flows through it (Fig 1). Lange does not explicitly disclose compensating reservoir to be force-loaded or pressure-loaded such that the force-loading or pressure-loading separates air entrained in the coolant from the coolant. Lenz discloses [Para 0006 of Instant Application refers to Lenz as relevant prior art and discloses pressurized compensating reservoir and prevention of cavitation which inherently is formation of air bubbles] compensating reservoir (Fig 2, 18) to be force-loaded or pressure-loaded such that the force-loading or pressure-loading separates air entrained in the coolant from the coolant. [Further, as stated above, Examiner would like to record that out of cited Para 0018,0023,0047 in support of amendment, both 0018 and 0047 discusses impediment to air bubble formation due to pressure which is different from separation of air bubble(which implies air bubbles already formed and then being removed). In light of argument and cited paragraphs, Examiner will interpret using pressure as a way to impede air bubble formation]. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have formed machine cooling circuit of Lange with pressurized compensating reservoir as taught by Lenz in order to prevent cavitation which can lead to pressure and flow fluctuation and cooling inefficiency. PNG media_image1.png 774 818 media_image1.png Greyscale PNG media_image2.png 514 554 media_image2.png Greyscale Regarding Claim 2, Lange in view of Lenz discloses the machine cooling circuit according to claim 1. Lange in view of Lenz further discloses wherein the electric machine (Lange,12) comprises a housing (16 stator portion can be housing), in which a rotor (14) is rotatably accommodated in a rotor chamber (14c) and in which a stator (16) and a winding [0017] are accommodated in a stator chamber (16c), wherein the stator chamber is separated from the rotor chamber] (Fig 1 discloses 40 coolant circuit is separate from 60 coolant circuit which includes rotor), and wherein coolant (40 coolant) of the machine cooling circuit can at least partially flow around the stator and the winding [0017. Regarding Claim 3, Lange in view of Lenz discloses the machine cooling circuit according to claim 1. Lange in view of Lenz discloses wherein the machine cooling circuit is a self-deaerating cooling circuit [Para0049 of Instant application discloses “the force-loaded or pressure-loaded compensating reservoir 23 thereby represents a self-deaerating element” which is already achieved as shown above by combining Lange with Lenz] . Regarding Claim 4, Lange in view of Lenz discloses the machine cooling circuit according to claim 3. Lange in view of Lenz discloses wherein the machine cooling circuit is a closed, self-deaerating cooling circuit [Para0049 of Instant application discloses “the force-loaded or pressure-loaded compensating reservoir 23 thereby represents a self-deaerating element” and circuit becomes closed when Lange compensating reservoir is substituted with Lenz pressurized compensating reservoir, which is already achieved as shown above by combining Lange with Lenz] Regarding Claim 7, Lange in view of Lenz discloses the machine cooling circuit according to claim 1. Lange in view of Lenz further discloses wherein the machine cooling circuit (40) is integrated into an overall cooling circuit (40,50,60) of the motor vehicle in the form of a cooling circuit, through which flow can independently take place (42 is a pump that causes flow independently through 40). Regarding Claim 8, Lange in view of Lenz discloses the machine cooling circuit according to claim 1. Lange in view of Lenz further discloses wherein the coolant (40 coolant) is a dielectric fluid [0017]. Regarding Claim 9, Lange in view of Lenz discloses the machine cooling circuit according to claim 1. Lange in view of Lenz further discloses an overall cooling circuit (40,50,60) of a motor vehicle comprising: the machine cooling circuit (40) according to claim 1, which includes: a first cooling circuit (50) for cooling at least one pulse inverter (20)[0026 discloses “pulse inverter”]; and a second cooling circuit (60) for cooling [0029] a transmission (30) of the motor vehicle. Regarding Claim 10, Lange in view of Lenz discloses the machine cooling circuit according to claim 9. Lange in view of Lenz further discloses wherein flow can take place through the first cooling circuit (50), the second cooling circuit (60), and the machine cooling circuit (40) separately from one another (Fig 1). Regarding Claim 12, Lange in view of Lenz discloses the machine cooling circuit according to claim 9. Lange in view of Lenz further discloses wherein the first cooling circuit (50) is thermally coupled [0030] to the second cooling circuit (60) with the aid of a heat exchanger (64) of the overall cooling circuit. Regarding Claim 13, Lange in view of Lenz discloses the machine cooling circuit according to claim 12. Lange in view of Lenz further discloses wherein the machine cooling circuit (40) is thermally coupled (44 is heat exchanger) to the first cooling circuit (50) with the aid of a heat exchanger (44) of the overall cooling circuit. Regarding Claim 14, Lange in view of Lenz discloses the machine cooling circuit according to claim 9. Lange in view of Lenz further discloses a motor vehicle [Abstract], comprising: an electric machine (12) for propulsion (12 is connected to transmission 30); and the overall cooling circuit (40,50,60) according to claim 9. Regarding Claim 18, Lange in view of Lenz discloses the machine cooling circuit according to claim 1. Lange in view of Lenz further discloses further comprising a pump (Lange, 42) configured to convey the coolant through the machine cooling circuit (Fig 1) but does not disclose wherein the compensating reservoir is arranged in an inlet of the pump to inhibit cavitation within the coolant. Lenz further discloses (Fig 1) compensating reservoir (18) is arranged in an inlet of the pump (16) to inhibit cavitation within the coolant [Para 0009 discloses “The invention can counteract the resulting cavitation in the coolant pump”]. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have formed machine cooling circuit of Lange in view of Lenz with pressurized compensating reservoir arranged at pump inlet as further taught by Lenz in order to prevent cavitation which can lead to pressure and flow fluctuation and cooling inefficiency. PNG media_image3.png 360 674 media_image3.png Greyscale Claims 5,19 are rejected under 35 U.S.C. 103 as being unpatentable over Lange in view of Lenz and Mohlin et al (WO2021235991A1), hereinafter Mohlin. Regarding Claim 5, Lange in view of Lenz discloses the machine cooling circuit according to claim 1. Lange in view of Lenz does not explicitly disclose a microbubble separator is arranged in the machine cooling circuit. Mohlin discloses (Fig 1) a microbubble separator (40) is arranged in the machine cooling circuit (Further,the expansion tank 30 is two phase where pressure is being created, therefore is being applied on coolant as evidenced by pressure release valve 34). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have formed machine cooling circuit of Lange in view of Lenz modified by bubble separator of Mohlin in order to further reduce air in the cooling circuit which can lead to pressure and flow fluctuation and cooling inefficiency. PNG media_image4.png 410 462 media_image4.png Greyscale Regarding Claim 19, Lange in view of Lenz and Muller discloses the machine cooling circuit according to claim 5. Lange in view of Lenz and Muller does not explicitly disclose wherein the microbubble separator is arranged between the electric machine and the compensating reservoir. Muller further discloses (Fig 1) wherein the microbubble separator (40) is arranged between the electric machine (11) and the compensating reservoir (30). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have formed machine cooling circuit of Lange in view of Lenz and Muller with location of bubble separator as further taught by Mohlin in order to further reduce air in the cooling circuit before entering heat source which can lead to pressure and flow fluctuation and cooling inefficiency. Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Lange in view of Lenz and Oechslen (US20210001714A1) Regarding Claim 6, Lange in view of Lenz discloses the machine cooling circuit according to claim 1. Lange in view of Lenz further discloses further comprising a conveyance means (42) formed in the machine cooling circuit (40) upstream of the heat exchanger (44) formed in the machine cooling circuit (40) but does not explicitly disclose conveyance means arranged downstream of a filter element formed in the machine cooling circuit relative to a heat exchanger and upstream of the heat exchanger relative to the filter element. Oechslen discloses (Fig 1) conveyance means (22) arranged downstream of a filter element (21) formed in the machine cooling circuit (7,40) relative to a heat exchanger (9) and upstream of the heat exchanger relative to the filter element (Fig 1). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have formed machine cooling circuit of Lange in view of Lenz with conveyance means arrangement of Oechslen in order to have filtered coolant come in at the inlet of the pump before pumping the coolant thereby keeping coolant quality best for heat removal needs. PNG media_image5.png 554 540 media_image5.png Greyscale Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over Lange in view of Lenz and Greiter (DE102019126914A1 English translation) Regarding Claim 11, Lange in view of Lenz discloses the machine cooling circuit according to claim 9. Lange in view of Lenz further discloses wherein a first conveyance means (Lange,66) of the second cooling circuit (60) and a second conveyance means (42) of the machine cooling circuit (40) are configured but does not explicitly disclose they are configured as a tandem pump. Greiter discloses (Fig 1) a first conveyance means (29) of the second cooling circuit (G) and a second conveyance means (57) of the machine circuit (E)are configured as a tandem pump (58 runs off common shaft 61). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have formed machine cooling circuit of Lange in view of Lenz with a tandem pump to pump coolant into both machine cooling and second cooling circuit in order to minimized componentry and simplify [Grieter Para 0011]. PNG media_image6.png 512 738 media_image6.png Greyscale Claims 15-17 are rejected under 35 U.S.C. 103 as being unpatentable over Lange in view of Lenz and Muller et al (DE102020001062A1 English translation), hereinafter Muller. Regarding Claim 15, Lange in view of Lenz discloses the machine cooling circuit according to claim 1 Lange in view of Lenz further discloses wherein the compensating reservoir is force-loaded or pressure-loaded but does not disclose by a spring element . Muller discloses (Fig 5) compensating reservoir (30) is force-loaded or pressure-loaded by a spring element (38)configured to exert a force on the coolant 926). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have formed machine cooling circuit of Lange in view of Lenz with spring based compensating reservoir as taught by Muller in order have design choice of pressurization based on trade off between cost and or pressure control reasons. PNG media_image7.png 426 460 media_image7.png Greyscale Regarding Claim 16, Lange in view of Lenz and Muller discloses the machine cooling circuit according to claim 15. Lange in view of Lenz and Muller further discloses wherein the force (Muller) exerted on the coolant (26) is configured to be continuously applied (spring 38 force is continuous) in the machine cooling circuit. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have formed machine cooling circuit of Lange in view of Lenz and Muller with continuous spring force as taught by Muller in order to have pressurization of coolant at all times thereby preventing cavitation. Regarding Claim 17, Lange in view of Lenz and Muller discloses the machine cooling circuit according to claim 16. Lange in view of Lenz and Muller further discloses wherein the compensating reservoir (Lange, 46)(Lenz,18) is arranged remotely (any location can be remote) of heat sources within the vehicle relative to other components of the machine cooling circuit (underlined is not in cited specification Para 0050 or in any other part of specification per Examiner search, so it is not being considered) so as to inhibit microbubble formation (combination with Lenz ) within the coolant. Conclusion THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action. Any inquiry concerning this communication or earlier communications from the examiner should be directed to VISWANATHAN SUBRAMANIAN whose telephone number is (571)272-4814. The examiner can normally be reached Monday - Friday 8:30 am - 5:00 pm. 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, Christopher M Koehler can be reached at 5712723560. 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. /VISWANATHAN SUBRAMANIAN/Examiner, Art Unit 2834 /CHRISTOPHER M KOEHLER/Supervisory Patent Examiner, Art Unit 2834
Read full office action

Prosecution Timeline

Nov 28, 2023
Application Filed
Oct 01, 2025
Non-Final Rejection — §103, §112
Dec 22, 2025
Response Filed
Jan 13, 2026
Examiner Interview (Telephonic)
Jan 16, 2026
Examiner Interview Summary
Mar 18, 2026
Final Rejection — §103, §112 (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
80%
Grant Probability
99%
With Interview (+22.9%)
2y 9m
Median Time to Grant
Moderate
PTA Risk
Based on 198 resolved cases by this examiner. Grant probability derived from career allow rate.

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