Prosecution Insights
Last updated: April 19, 2026
Application No. 18/655,104

NATURAL GAS ENGINE START AND LOAD SYSTEM

Final Rejection §103
Filed
May 03, 2024
Examiner
LIETHEN, KURT PHILIP
Art Unit
3747
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Flanders Electric Motor Service LLC
OA Round
2 (Final)
79%
Grant Probability
Favorable
3-4
OA Rounds
2y 4m
To Grant
88%
With Interview

Examiner Intelligence

Grants 79% — above average
79%
Career Allow Rate
338 granted / 426 resolved
+9.3% vs TC avg
Moderate +9% lift
Without
With
+8.7%
Interview Lift
resolved cases with interview
Typical timeline
2y 4m
Avg Prosecution
37 currently pending
Career history
463
Total Applications
across all art units

Statute-Specific Performance

§101
6.1%
-33.9% vs TC avg
§103
54.3%
+14.3% vs TC avg
§102
20.5%
-19.5% vs TC avg
§112
17.1%
-22.9% vs TC avg
Black line = Tech Center average estimate • Based on career data from 426 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 . Claim Status Claims 1-20 are pending in the application and have been examined. Response to Arguments Applicant’s arguments with respect to claim(s) 1-20 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument. Claim Rejections - 35 USC § 103 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(s) 1, 9-13, and 16 are rejected under 35 U.S.C. 103 as being unpatentable over Okland, Hoshino et al. (US 2016/0097405 A1) hereinafter Hoshino, and Wejrzanowski et al. (US 8,118,627 B2) hereinafter Wejrzanowski. Claim 1: Okland discloses A system comprising: an engine connectable to a working load [Fig. 2, G1], wherein the working load varies over time between a first load and an operational load greater than the first load [¶68, "external load"]; an electric motor connected to the engine and operable to drive, or be driven by, the engine; a variable frequency drive connected to the electric motor; and a system controller connected to the variable frequency drive [¶¶68, 76]. Okland doesn’t explicitly disclose wherein the system controller is programmed to command the variable frequency drive to change a selected mode of the electric motor according to an operational state of the engine, wherein the selected mode comprises, over the time, each of a plurality of modes during operation of the engine, and wherein the plurality of modes comprises: an electrical generation mode comprising the electric motor operating as a generation load on the engine when the working load falls to an intermediate load below the operational load, wherein the generation load combined with the intermediate load comprises about the operational load, a standby mode comprising the electric motor operating as a standby load on the engine when the working load about equals the operational load, and Hoshino discloses wherein the system controller is programmed to command the variable frequency drive to change a selected mode of the electric motor according to an operational state of the engine, wherein the selected mode comprises, over the time, each of a plurality of modes during operation of the engine, and wherein the plurality of modes comprises [Fig. 7; ¶¶61-70]: an electrical generation mode comprising the electric motor operating as a generation load on the engine when the working load falls to an intermediate load below the operational load, wherein the generation load combined with the intermediate load comprises about the operational load [S22, S40a], a standby mode comprising the electric motor operating as a standby load on the engine when the working load about equals the operational load [S14; S30a]. Wejrzanowski discloses a drive mode comprising the electric motor applying mechanical power to the engine [col. 7, line 49 to col 8, line 7]. It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine the genset of Okland with the operating modes of Hoshino the provide additional charge to the battery when necessary and stop when not required. It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine the genset of Okland and Hoshino with the motor control of Wejrzanowski to perform engine starting and allow for a power boost that would enable decreasing the size of the engine. Claim 9: Okland, Hoshino, and Wejrzanowski, as shown in the rejection above, disclose all the limitations of claim 1. Okland also discloses further comprising: a battery connected to the variable frequency drive, wherein, in the electrical generation mode, the system controller is programmed to transmit electricity generated by the motor to the battery until the battery no longer accepts a charge; and an auxiliary load connected to the battery [¶89]. Claim 10: Okland and Wejrzanowski, as shown in the rejection above, disclose all the limitations of claim 9. Okland also discloses further comprising: an inverter connected between the battery and the auxiliary load [¶¶91-93]. Claim 11: Okland, Hoshino, and Wejrzanowski, as shown in the rejection above, disclose all the limitations of claim 9. Okland also discloses wherein the auxiliary load comprises: electrical power used by the variable frequency drive and the system controller. Claim 12: Okland, Hoshino, and Wejrzanowski, as shown in the rejection above, disclose all the limitations of claim 1. Okland also discloses further comprising a central controller connected to the system controller, wherein the central controller comprises: a processor programmed to control the system controller; and a user interface, in communication with the processor, and configured to display a status of a component of the system [¶100]. Claim 13: Okland, Hoshino, and Wejrzanowski, as shown in the rejection above, disclose all the limitations of claim 12. Okland also discloses wherein the central controller is programmed to: predict the operational state of the engine to generate a prediction; and control the generation load according to the prediction [¶88]. Claim 16: Okland discloses a method comprising: applying a working load to an engine, wherein: the working load varies over time between a first load and an operational load greater than the first load [Fig. 2, G1; ¶68, "external load"], the engine is connected to an electric motor, wherein the electric motor is operable to drive, or be driven by, the engine, the electric motor is connected to a variable frequency drive, and a system controller is connected to the variable frequency drive [¶¶68, 76]. Okland doesn’t explicitly disclose changing, by the variable frequency drive according to a first command from the system controller and responsive to the working load falling to an intermediate load below the operational load, the electric motor to an electrical generation mode that applies a generation load to the engine, wherein the generation load combined with the intermediate load comprises about the operational load; changing, by the variable frequency drive according to a second command from the system controller and responsive to the working load being about equal to the operational load, the total load applied by the motor to the engine to a standby load, the electric motor to a standby mode that applies a standby load on the engine; changing, by the variable frequency drive according to a third command from the system controller, the electric motor to a drive mode that applies mechanical power to the engine, wherein, over the time, the electric motor operates at least once in each of the generation load, the standby mode, and the drive mode. Hoshino discloses changing, by the variable frequency drive according to a first command from the system controller and responsive to the working load falling to an intermediate load below the operational load, the electric motor to an electrical generation mode that applies a generation load to the engine, wherein the generation load combined with the intermediate load comprises about the operational load [S22, S40a]; changing, by the variable frequency drive according to a second command from the system controller and responsive to the working load being about equal to the operational load, the total load applied by the motor to the engine to a standby load, the electric motor to a standby mode that applies a standby load on the engine [¶¶68, 76]; wherein, over the time, the electric motor operates at least once in each of the generation load, the standby mode, and the drive mode [Fig. 7; ¶¶61-70]. Wejrzanowski discloses changing, by the variable frequency drive according to a third command from the system controller, the electric motor to a drive mode that applies mechanical power to the engine [col. 7, line 49 to col 8, line 7]. It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine the genset of Okland with the operating modes of Hoshino the provide additional charge to the battery when necessary and stop when not required. It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine the genset of Okland and Hoshino with the motor control of Wejrzanowski to perform engine starting and allow for a power boost that would enable decreasing the size of the engine. Claim(s) 2-3 is/are rejected under 35 U.S.C. 103 as being unpatentable over Okland, Hoshino, and Wejrzanowski as applied to claim 1 above, and further in view of Zillmer et al. (US 2013/0019849 A1) hereinafter Zillmer. Claim 2: Okland, Hoshino, and Wejrzanowski, as shown in the rejection above, disclose all the limitations of claim 1. Okland doesn’t explicitly disclose further comprising: a load resistor connected to the variable frequency drive; and a battery connected to the variable frequency drive, wherein, in the electrical generation mode, the system controller is programmed to transmit electricity generated by the motor to the battery until the battery no longer accepts a charge, and to transmit the electricity generated by the battery to the load resistor when the battery no longer accepts the charge. However, Zillmer does disclose further comprising: a load resistor connected to the variable frequency drive; and a battery connected to the variable frequency drive, wherein, in the electrical generation mode, the system controller is programmed to transmit electricity generated by the motor to the battery until the battery no longer accepts a charge, and to transmit the electricity generated by the battery to the load resistor when the battery no longer accepts the charge. [¶8] It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine the genset of Okland, Hoshino, and Wejrzanowski with the load resister of Zillmer to provide a place for the excess power to go and balance the circuit. Claim 3: Okland, Hoshino, Wejrzanowski, and Zillmer as shown in the rejection above, disclose all the limitations of claim 2. Okland doesn’t explicitly disclose further comprising: a direct current to direct current (DC/DC) converter operationally connected between the variable frequency drive and the battery. Wejrzanowski does disclose further comprising: a direct current to direct current (DC/DC) converter operationally connected between the variable frequency drive and the battery. [col. 3, lines 6-9] It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine the genset of Okland and Hoshino with the electrical configuration of Wejrzanowski to supply onboard electrical power to required devices. Claim(s) 4 is/are rejected under 35 U.S.C. 103 as being unpatentable over Okland, Wejrzanowski, and Zillmer as applied to claim 2 above, and further in view of Kim (US 2019/0135128 A1) hereinafter Kim. Claim 4: Okland, Hoshino, Wejrzanowski, and Zillmer as shown in the rejection above, disclose all the limitations of claim 2. Okland doesn’t explicitly disclose further comprising: a fan directed to blow air from the load resistor. However, Kim does disclose further comprising: a fan directed to blow air from the load resistor. [¶11] It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine the genset of Okland, Hoshino, Wejrzanowski, and Zillmer with the fan of Kim to cool down the resister thus increasing efficiency and reducing heat. Claim(s) 5, 14, and 15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Okland and Wejrzanowski as applied to claim 1 above, and further in view of McAndrew (US 2016/0376976 A1) hereinafter McAndrew. Claim 5: Okland, Hoshino, and Wejrzanowski, as shown in the rejection above, disclose all the limitations of claim 1. Okland doesn’t explicitly disclose further comprising: an engine liquid cooling system connected to the engine. However, McAndrew does disclose further comprising: an engine liquid cooling system connected to the engine. [¶12] It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine the genset of Okland, Hoshino, and Wejrzanowski with the liquid cooling of McAndrew to provide necessary cooling for optimal engine operation. Claim 14: Okland, Hoshino, and Wejrzanowski, as shown in the rejection above, disclose all the limitations of claim 1. Okland doesn’t explicitly disclose wherein the engine comprises a natural gas engine fueled by natural gas. However, McAndrew does disclose wherein the engine comprises a natural gas engine fueled by natural gas. [¶10] It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine the genset of Okland, Hoshino, and Wejrzanowski with the natural gas of McAndrew to provide an available fuel source to operate the engine. Claim 15: Okland, Hoshino, and Wejrzanowski, as shown in the rejection above, disclose all the limitations of claim 1. Okland doesn’t explicitly disclose further comprising a trailer, wherein: the variable frequency drive and the system controller are housed in an electrical unit connected to the motor, and the engine, the motor, and the electrical unit are disposed on the trailer. However, McAndrew does disclose further comprising a trailer, wherein: the variable frequency drive and the system controller are housed in an electrical unit connected to the motor, and the engine, the motor, and the electrical unit are disposed on the trailer. [¶¶6-7] It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine the genset of Okland, Hoshino, and Wejrzanowski and the trailer of McAndrew to provide a means for transporting the engine and generator. Claim(s) 6 is/are rejected under 35 U.S.C. 103 as being unpatentable over Okland, Hoshino, and Wejrzanowski as applied to claim 1 above, and further in view of Sonnleitner et al. (US 2016/0075345 A1) hereinafter Sonnleitner. Claim 6: Okland, Hoshino, and Wejrzanowski, as shown in the rejection above, disclose all the limitations of claim 1. Okland doesn’t explicitly disclose further comprising: a pre-heating system connected to the engine. However, Sonnleitner does disclose further comprising: a pre-heating system connected to the engine. [¶39] It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine the genset of Okland, Hoshino, and Wejrzanowski with the preheating system of Sonnleitner to bring the engine to optimal operating temperature thus increasing efficiency. Claim(s) 7 is/are rejected under 35 U.S.C. 103 as being unpatentable over Okland, Hoshino, and Wejrzanowski as applied to claim 1 above, and further in view of Kim (US 2019/0135128 A1) hereinafter Kim. Claim 7: Okland, Hoshino, and Wejrzanowski, as shown in the rejection above, disclose all the limitations of claim 1. Okland doesn’t explicitly disclose further comprising: an electronics cooling system connected to at least the variable frequency drive. However, Kim does disclose further comprising: an electronics cooling system connected to at least the variable frequency drive. [¶11] It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine the genset of Okland, Hoshino, and Wejrzanowski with the cooling system of Kim to cool down the resister thus increasing efficiency and reducing heat. Claim(s) 8 is/are rejected under 35 U.S.C. 103 as being unpatentable over Okland, Hoshino, and Wejrzanowski as applied to claim 1 above, and further Zillmer, Kim, McAndrew, and Sonnleitner. Okland, Hoshino, and Wejrzanowski, as shown in the rejection above, disclose all the limitations of claim 1. Claim 8 is rejected for similar reasons as claims 2-7. Claim(s) 17 is/are rejected under 35 U.S.C. 103 as being unpatentable over Okland, Hoshino, and Wejrzanowski as applied to claim 16 above, and further in view of Wejrzanowski. Okland, Hoshino, and Wejrzanowski, as shown in the rejection above, disclose all the limitations of claim 16. Okland doesn’t explicitly disclose further comprising: changing, prior to applying the working load to the engine and by the variable frequency drive according to a third command from the system controller, the motor to a drive mode; and starting, by the motor and responsive to the drive mode, the engine. However, Wejrzanowski does disclose further comprising: changing, prior to applying the working load to the engine and by the variable frequency drive according to a third command from the system controller, the motor to a drive mode; and starting, by the motor and responsive to the drive mode, the engine. [col. 7, line 49 to col 8, line 7] It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine the genset of Okland and Hoshino with the motor control of Wejrzanowski to perform engine starting and allow for a power boost that would enable decreasing the size of the engine. Claim 18: Okland, Hoshino, and Wejrzanowski, as shown in the rejection above, disclose all the limitations of claim 17. Okland doesn’t explicitly disclose further comprising: transmitting, when the motor is under the generation load, electrical energy generated by the motor to a battery; and providing, from the battery, power to the variable frequency drive and the system controller. However, Zillmer does disclose further comprising: transmitting, when the motor is under the generation load, electrical energy generated by the motor to a battery; and providing, from the battery, power to the variable frequency drive and the system controller. [¶8] It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine the genset of Okland, Hoshino, and Wejrzanowski, with the load resister of Zillmer to provide a place for the excess power to go and balance the circuit. Claim 18: Okland, Hoshino, Wejrzanowski, and Zillmer as shown in the rejection above, disclose all the limitations of claim 18. Claim 18 is rejected for similar reasons as claims 2, 4, 5, and 7. Claim 20: Okland, Hoshino, Wejrzanowski, Zillmer, Kim, and McAndrew as shown in the rejection above, disclose all the limitations of claim 19. Okland doesn’t explicitly disclose wherein the variable frequency drive, the battery, the electronics cooling system, and the system controller are housed in an electronics unit, wherein the working load comprises a pump, wherein the engine is connected to the pump via a transmission, and wherein the method further comprises: placing the motor, the engine, the transmission, the pump, and the electronics unit on a trailer; hauling the trailer to an exploration and production site; connecting the pump in an operational relationship with a wellbore disposed in the exploration and production site; pumping, with the pump operated by the engine, a product from the wellbore; and controlling, while pumping, the motor between the generation load and the standby load. However, Coskrey does disclose wherein the variable frequency drive, the battery, the electronics cooling system, and the system controller are housed in an electronics unit, wherein the working load comprises a pump, wherein the engine is connected to the pump via a transmission, and wherein the method further comprises: placing the motor, the engine, the transmission, the pump, and the electronics unit on a trailer; hauling the trailer to an exploration and production site; connecting the pump in an operational relationship with a wellbore disposed in the exploration and production site; pumping, with the pump operated by the engine, a product from the wellbore; and controlling, while pumping, the motor between the generation load and the standby load. [¶¶27-28] It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine the genset of Okland, Hoshino, Wejrzanowski, Zillmer, Kim, and McAndrew with the pumping arrangement of Coskrey to utilize the output of the system for hydraulic fracturing. Conclusion Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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 KURT P LIETHEN whose telephone number is (313)446-6596. The examiner can normally be reached Mon - Fri, 8 AM - 4 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, Lindsay Low can be reached at (571)272-1196. 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. KURT P. LIETHEN Primary Examiner Art Unit 3747 /KURT PHILIP LIETHEN/ Primary Examiner, Art Unit 3747
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Prosecution Timeline

May 03, 2024
Application Filed
Sep 25, 2025
Non-Final Rejection — §103
Dec 05, 2025
Interview Requested
Dec 12, 2025
Applicant Interview (Telephonic)
Dec 12, 2025
Examiner Interview Summary
Dec 15, 2025
Response Filed
Mar 15, 2026
Final Rejection — §103 (current)

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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
79%
Grant Probability
88%
With Interview (+8.7%)
2y 4m
Median Time to Grant
Moderate
PTA Risk
Based on 426 resolved cases by this examiner. Grant probability derived from career allow rate.

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