DETAILED ACTION
This is in response to the Request for Continued Examination filed 10/29/2025 wherein claims 9 and 18-19 are canceled and claims 1-8, 10-17, and 20-21 are presented for examination.
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 .
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 (i.e., changing from AIA to pre-AIA ) 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.
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 10/29/2025 has been entered.
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 1-8, 10-17 and 20 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention. Applicant claims “windmilling of the propulsor during flight of the aircraft is insufficient for the high-pressure spool to achieve the second threshold rotational speed without assistance from the starter” (Claim 1) and “wherein the first initial fuel flow rate and the second initial fuel flow rate are configured to cause an air:fuel ratio to be equal” (Claim 11 - emphasis added). Applicant’s specification does not describe whether windmilling for the propulsor during flight of the aircraft for the high pressure spool to achieve the second threshold rotational speed without assistance is sufficient or not. Although Applicant’s specification states “modification of the fuel flow rate may cause the air:fuel ratio to remain substantially similar to the air:fuel ratio during a normal, ground start. In some examples substantially similar or substantially equal, as used herein, comprise values within 10%, or within 20%, of the stated value” in Paragraph 0067, Applicant’s specification does not describe the air:fuel ratios being equal when fuel flows at the first initial fuel flow rate and the second initial fuel flow rate. Therefore, the claims contain subject matter which was not described in the specification in such a way as to reasonably convey to one having ordinary skill in the art that Applicant had possession of the claimed invention at the time the application was filed.
Claims 12-17 and 20 are rejected for the same reasons above based on their dependency to claim 11.
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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1-4, 7, and 10 are rejected under 35 U.S.C. 103 as being unpatentable over Eick et al. (US 2006/0266047) in view of Hon et al. (US 2018/0354632), Muldoon et al. (US 2022/0396365), DeVita et al. (US 9,428,267), Swann et al. (US 2023/0192303), and Fitzgerald et al. (US 2014/0238032).
Regarding Independent Claim 1, Eick teaches (Figures 1-2) a starting apparatus (see Figure 1) for a gas turbine engine (18) of an aircraft (Paragraph 0016), the starting apparatus (see Figure 1) comprising:
a fuel supply system (10);
a combustor (within 18; see Figure 1 and Paragraph 0009);
wherein the fuel system (10) is configured to:
cause fuel (from 12) to be introduced to the combustor (within 18, see Figure 1 and Paragraph 0009) of the gas turbine engine (18) at a first threshold rotational speed of the gas turbine engine (18) during a normal starting operation when the aircraft is on the ground (see Paragraphs 0004-0005 and 0009);
cause fuel (from 12) to be introduced to the combustor (within 18, see Figure 1 and Paragraph 0009) at a second threshold speed of the gas turbine engine (18) during an emergency in-flight restarting operation in which the aircraft is in-flight (see Paragraphs 0005, 0009, 0019);
wherein:
the second threshold rotational speed is lower than the first threshold rotational speed (Paragraphs 0009, 0019, and 0022),
introducing fuel at the second threshold rotational speed (Paragraphs 0005, 0009, and 0019) results in a higher temperature in a turbine of the gas turbine engine (due to less airflow provided through the turbomachine to cool the turbomachine and reducing an exhaust gas temperature) than introducing fuel at the first threshold rotational speed (Paragraphs 0004-0005 and 0009),
windmilling of the propulsor during flight of the aircraft is insufficient for the high-pressure spool to achieve the second threshold rotational speed without assistance from the starter (variables such as airspeed when the restart becomes necessary may reduce the ability of the engine to be reliably windmill restarted; see Paragraph 0005);
wherein the fuel is introduced at a first initial fuel flow rate during the normal starting operation (a precisely metered supply of fuel is mixed with compressed air in the combustor, wherein the fuel is supplied to the combustion chamber at a first rate for combustion to start; see Paragraphs 0002, 0004, and 0009),
wherein the fuel is introduced at a second initial fuel flow rate during the emergency in-flight restarting operation (a precisely metered supply of fuel is mixed with compressed air in the combustor, wherein fuel from the main pump is suppled at a second rate that is less than the first rate; see Paragraphs 0002, 0005, and 0009).
Eick does not teach a plurality of gas turbine engines of an aircraft, a high pressure spool, the starter configured to cause rotation of the high-pressure spool, wherein the gas turbine engine comprises a propulsor connected to a low pressure spool that includes a free-power turbine, the fuel supply system being controlled by a controller, causing the stater to generate rotation of the high pressure spool of the gas turbine engine during the emergency in-flight restarting operation, or wherein the first initial fuel flow rate and the second initial fuel flow rate are configured to cause an air:fuel ratio to be substantially similar.
Hon teaches (Figures 1-9) that a conventional commercial aircraft includes a fuselage, a pair of wings, and a propulsion system that typically includes at least two aircraft engines, such as turbofan jet engines (Paragraph 0002). It is noted that Hon also teaches that higher threshold speeds result in more airflow provided through the turbomachine to cool the turbomachine once the re-ignition is initiated, thereby reducing the exhaust gas temperature (see Paragraph 0049 of Hon).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Eick to include the plurality of gas turbine engines of an aircraft, as taught by Hon, in order to provide thrust (Paragraph 0002 of Hon). Eick in view of Hon does not teach a high pressure spool, the starter configured to cause rotation of the high-pressure spool, wherein the gas turbine engine comprises a propulsor connected to a low pressure spool that includes a free-power turbine, the fuel supply system being controlled by a controller, causing the stater to generate rotation of the high pressure spool of the gas turbine engine during the emergency in-flight restarting operation, or wherein the first initial fuel flow rate and the second initial fuel flow rate are configured to cause an air:fuel ratio to be substantially similar.
Muldoon teaches (Figures 1-3) an aircraft gas turbine engine (20) including a high pressure spool (32), a starter (182) configured to cause rotation of the high-pressure spool (32), wherein the gas turbine engine (20) comprises a propulsor (42) connected to a low pressure spool (30), and a controller (156) that causes the starter (182) to generate rotation of the high-pressure spool (32) of the gas turbine engine (20) during an emergency in-flight restarting operation (see Paragraphs 0040 and 0066).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Eick in view of Hon to include the high pressure spool, the starter configured to cause rotation of the high-pressure spool, wherein the gas turbine engine comprises a propulsor connected to a low pressure spool, and causing the stater to generate rotation of the high pressure spool of the gas turbine engine during the emergency in-flight restarting operation, as taught by Muldoon, in order to have a high pressure turbine rotationally drive a high speed spool in response to the expansion of the air and fuel mixture that has been burned in the combustor, in order to drive air along a bypass flow path to provide thrust, and in order to expand an in-flight restart envelope (Paragraphs 0033, 0036, 0040 of Muldoon). Eick in view of Hon and Muldoon does not teach a free-power turbine, the fuel supply system being controlled by a controller, or wherein the first initial fuel flow rate and the second initial fuel flow rate are configured to cause an air:fuel ratio to be substantially similar.
DeVita teaches (Figures 1-3) a fuel supply system being controlled by a controller during normal operation and in-flight restarting (see Column 4, lines 23-36).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Eick in view of Hon and Muldoon to have the fuel supply system be controlled by a controller, as taught by DeVita, in order to provide command signals to the fuel system during normal operation and in-flight starting (Column 4, lines 23-36 of DeVita). Eick in view of Hon, Muldoon, and DeVita does not teach a free-power turbine or wherein the first initial fuel flow rate and the second initial fuel flow rate are configured to cause an air:fuel ratio to be substantially similar.
Swann teaches (Figures 1-25) a gas turbine engine (10) for an aircraft (see title), wherein the gas turbine engine (10) can include a propulsor connected to a low pressure spool that includes a free-power turbine (see Paragraph 0392).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Eick in view of Hon, Muldoon, and Devita to have the free-power turbine, as taught by Swann, in order to provide the majority of the propulsive thrust (Paragraph 0392 of Swann). It is further noted that a simple substitution of one known element (in this case, the propulsor connected to the low pressure turbine as taught by Muldoon) for another (in this case, the propulsor connected to the free-power turbine as taught by Swann) to obtain predictable results (in this case, provide propulsive thrust) was an obvious extension of prior art teachings, KSR, 550 U.S. at 415-421, 82 USPQ2d at 1396, MPEP 2141 III B. Eick in view of Hon, Muldoon, DeVita, and Swann does not teach the first initial fuel flow rate and the second initial fuel flow rate are configured to cause an air:fuel ratio to be substantially similar.
Fitzgerald teaches (Paragraphs 0003 and 0038) that an equivalence ratio (a ratio of air to fuel in the air-fuel mixture being combusted in the combustion chamber; see Paragraph 0038) being too low or too high can result in flame blowout, over-firing, hardware distress, a reduction in component life of the combustion system, and/or a potential for power outage (Paragraph 0003). Therefore, the ratio of air to fuel being combusted in the combustion chamber is recognized as a result-effective variables, i.e. a variable which achieves a recognized result. In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977); MPEP 2144.05(II)(B). In this case, the recognized result is that increasing the air to fuel ratio too high results in over-firing and decreasing the air to fuel ratio too low results in flame blowout, which leads to undesired combustion dynamics causing hardware distress and a reduction in component life (see Paragraph 0003 of Fitzgerald).
Therefore, since the general conditions of the claim, i.e. that the ratio of air to fuel delivered to the combustor should be controlled so that it is not too high or too low, were disclosed in the prior art by Fitzgerald, it is not inventive to discover the optimum workable range by routine experimentation, and it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to provide the equivalence ratio as taught by Fitzgerald in order to avoid flame blowout, over-firing, undesired dynamics, reduction in component life, and power outage. It has been held that “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955); MPEP 2144.05(II)(A).
It is noted that the term “introduce” is interpreted as “to insert or inject” as defined by Collins English Dictionary.
Regarding Claim 2, Eick in view of Hon, Muldoon, DeVita, Swann, and Fitzgerald teaches the invention as claimed and as discussed above. Eick further teaches (Figures 1-9) wherein introducing fuel at the second rotational speed (see Paragraphs 0005, 0009, and 0019) results in a turbine temperature that is above a critical turbine temperature of the turbine (due to an insufficient amount of airflow that is provided through the turbomachine to cool the turbomachine once re-ignition is initiated, which would reduce an exhaust gas temperature during restart).
It is noted that Hon also teaches (Figures 1-9) wherein introducing fuel at the second rotational speed results in a turbine temperature that is above a critical turbine temperature of the turbine (Paragraphs 0006, 0049, and 0106 of Hon).
Regarding Claim 3, Eick in view of Hon, Muldoon, DeVita, Swann, and Fitzgerald teaches the invention as claimed and as discussed above. Eick further teaches (Figures 1-9) wherein operation of the turbine above the critical temperature reduces a lifetime of the turbine (due to an insufficient amount of airflow that is provided through the turbomachine to cool the turbomachine once re-ignition is initiated, which would reduce an exhaust gas temperature during restart).
It is noted that Hon also teaches (Figures 1-9) wherein operation of the turbine above the critical temperature reduces a lifetime of the turbine (decreasing a lifespan of the components within the engine due to elevated internal temperatures; see Paragraph 0006 of Hon).
Regarding Claim 4, Eick in view of Hon, Muldoon, DeVita, Swann, and Fitzgerald teaches the invention as claimed and as discussed above. Eick further teaches (Figures 1-9) wherein the second threshold rotational speed is at least 10% lower than the first threshold speed (the first threshold speed is 10 percent of the rated speed and the second threshold speed is 5 percent of the rated speed; see Paragraphs 0004-0005, 0017, and 0019).
Regarding Claim 7, Eick in view of Hon, Muldoon, DeVita, Swann, and Fitzgerald teaches the invention as claimed and as discussed above. Eick further teaches (Figures 1-9) wherein the second threshold rotational speed is at least 10% lower than the first threshold speed (the first threshold speed is 10 percent of the rated speed and the second threshold speed is 5 percent of the rated speed; see Paragraphs 0004-0005, 0017, and 0019).
Regarding Claim 10, Eick in view of Hon, Muldoon, DeVita, Swann, and Fitzgerald teaches the invention as claimed and as discussed above. Eick further teaches (Figures 1-9) wherein the second initial fuel flow rate (a windmilling output rate of the main pump; see Paragraphs 0019-0020) is lower than the first initial fuel flow rate (all fuel necessary for normal operation; see Paragraphs 0017-0019).
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Eick et al. (US 2006/0266047) in view of Hon et al. (US 2018/0354632), Muldoon et al. (US 2022/0396365), DeVita et al. (US 9,428,267), Swann et al. (US 2023/0192303), and Fitzgerald et al. (US 2014/0238032) as applied to claim 1 above, and further in view of Smith, JR. et al. (US 2022/0106059).
Regarding Claim 5, Eick in view of Hon, Muldoon, DeVita, Swann, and Fitzgerald teaches the invention as claimed and as discussed above. Eick further teaches (Figures 1-9) wherein introducing fuel at the second rotational speed (see Paragraphs 0005,0009, and 0019) results in a turbine temperature that is above a critical turbine temperature of the turbine (due to an insufficient amount of airflow that is provided through the turbomachine to cool the turbomachine once re-ignition is initiated, which would reduce an exhaust gas temperature during restart). It is noted that Hon also teaches (Figures 1-9) wherein introducing fuel at the second rotational speed results in a turbine temperature that is above a critical turbine temperature of the turbine (Paragraphs 0006, 0049, and 0106 of Hon). Eick in view of Hon, Muldoon, DeVita, Swann, and Fitzgerald does not teach wherein the controller is further configured: to generate a data record indicating that the temperature of the turbine has exceeded a temperature threshold.
Smith teaches (Figures 1-24) computing devices receiving sensor data and recording parameters such as exhaust gas temperature when an exhaust gas temperature threshold is exceeded (Paragraph 0204).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Eick in view of Hon, Muldoon, DeVita, Swann, and Fitzgerald to have the controller generate a data record indicating the temperature of the exhaust gas has exceeded a temperature threshold, as taught by Smith, in order to determine the cause of an unexpected behavior if the engine performs in an unexpected way (Paragraph 0003 of Smith).
Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Eick et al. (US 2006/0266047) in view of Hon et al. (US 2018/0354632), Muldoon et al. (US 2022/0396365), DeVita et al. (US 9,428,267), Swann et al. (US 2023/0192303), and Fitzgerald et al. (US 2014/0238032) as applied to claim 1 above, and further in view of Trivedi et al. (US 2023/0417148).
Regarding Claim 6, Eick in view of Hon, Muldoon, DeVita, Swann, and Fitzgerald teaches the invention as claimed and as discussed above. Eick further teaches (Figures 1-9) that the main fuel pump is sized so that it can provide fuel at a start-up rate when a starter turns the engine at about 10 percent of its rated speed (see Paragraph 0017). Eick in view of Hon, Muldoon, DeVita, Swann, and Fitzgerald does not teach that this rotational speed is from about 10% to about 40% of a cruising rotational speed, i.e., the cruising speed is between about 25% rated speed and about 100% rated speed.
Trivedi teaches that a turbine engine utilized to power an aircraft may exhibit cruise operating conditions at a rotational speed that is from about 50% to about 90% of the rated speed (Paragraph 0042).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Eick in view of Hon, Muldoon, DeVita, Swann, and Fitzgerald to have the cruising speed be between 25% rated speed and 100% rated speed, as taught by Trivedi, in order to operate the engine at a relatively high rotational speed for a sustained period of time after a climb phase and prior to descending to an approach phase (Paragraphs 0035 and 0042 of Trivedi).
Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Eick et al. (US 2006/0266047) in view of Hon et al. (US 2018/0354632), Muldoon et al. (US 2022/0396365), DeVita et al. (US 9,428,267), Swann et al. (US 2023/0192303), and Fitzgerald et al. (US 2014/0238032) as applied to claim 1 above, and further in view of Veilleux (US 2018/0045122).
Regarding Claim 8, Eick in view of Hon, Muldoon, DeVita, Swann, and Fitzgerald teaches the invention as claimed and as discussed above. Eick in view of Hon, Muldoon, DeVita, Swann, and Fitzgerald does not teach, as discussed so far, wherein the first threshold rotational speed is measured at the high-pressure spool of the gas turbine engine.
Veilleux further teaches (Figures 1-4) wherein the first threshold rotational speed is measured at the high-pressure spool (32, 33) of the gas turbine engine (due the starter being connected to the high pressure spool through the tower shaft; see Figure 1 and Paragraph 0024).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Eick in view of Hon, Muldoon, DeVita, Swann, and Fitzgerald to have the first threshold rotational speed be measured at the high-pressure spool of the gas turbine engine, as taught by Veilleux, in order to enable speed control over a starter operating range from zero speed to above a nominal ground-based engine starting speed for a starting spool of the gas turbine engine (see Paragraph 0024 of Veilleux).
Claims 11-14, 17, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Veilleux (US 2018/0045122) in view of Hon et al. (US 2018/0354632), Wasselin (US 2024/0003300), Thompson (US 2006/0032234), and Fitzgerald et al. (US 2014/0238032).
Regarding Independent Claim 11, Veilleux teaches (Figures 1-4) a starting method (see Figure 1) for a gas turbine engine (10) of an aircraft (see Figure 1 and Paragraph 0002), the starting method (see Figure 1) comprising:
causing, via a controller (130), fuel (from 110) to be introduced (via 112, 154) from a fuel supply (102) to a combustor (18) of the gas turbine engine (10) when a spool (33) of the gas turbine engine (10) is rotating (see Figures 1-2 and Paragraph 0024) at a first threshold rotational speed of the gas turbine engine during a normal starting operation in which the aircraft is grounded (a nominal ground-based engine starting speed of about 15%; see Paragraph 0041), wherein introducing (via 112, 154) fuel (from 110) at the first threshold rotational speed comprises introducing fuel at a first initial fuel flow rate (a required fuel flow to satisfy a stoichiometric fuel-air ratio to achieve light-off; see Paragraph 0041),
causing, via a controller (130), fuel (from 110) to be introduced from the fuel supply (102) to the combustor (18) when the spool (33) is rotating (see Figures 1-2 and Paragraph 0024) at a second threshold rotational speed of the gas turbine engine during an emergency in-flight restarting operation in which the aircraft is in-flight (a speed of about 5% set to model a windmilling condition for an in-flight restart; see Paragraph 0041), wherein introducing fuel at the second threshold rotational speed (Paragraph 0041) comprises introducing fuel at a second initial fuel flow rate (a required fuel flow to satisfy a stoichiometric fuel-air ratio to achieve light-off; see Paragraph 0041),
wherein the second threshold rotational speed is lower than the first threshold rotational speed (Paragraph 0041),
wherein introducing fuel (from 110) at the second threshold rotational speed (Paragraph 0041) results in a higher temperature in a turbine of the gas turbine engine (due to introducing fuel earlier in the spool-up process, resulting in higher temperatures in the combustor, and since less airflow provided through the turbomachine to cool the turbomachine and reducing an exhaust gas temperature).
Veilleux does not teach a plurality of gas turbine engines of an aircraft, causing, during the emergency restart operation, both an electric machine and an air turbine starter to output work that causes rotation of the spool of the gas turbine engine, or the first initial fuel flow rate and the second initial fuel flow rate are configured to cause an air:fuel ratio to be equal.
Hon teaches (Figures 1-9) that a conventional commercial aircraft includes a fuselage, a pair of wings, and a propulsion system that typically includes at least two aircraft engines, such as turbofan jet engines (Paragraph 0002).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Veilleux to include the plurality of gas turbine engines of an aircraft, as taught by Hon, in order to provide thrust (Paragraph 0002 of Hon). It is noted that Hon also teaches that higher threshold speeds result in more airflow provided through the turbomachine to cool the turbomachine once the re-ignition is initiated, thereby reducing the exhaust gas temperature (see Paragraph 0049 of Hon). Veilleux in view of Hon does not teach that the first initial fuel flow rate and the second initial fuel flow rate are configured to cause an air:fuel ratio to be equal or causing, during the emergency restart operation, both an electric machine and an air turbine starter to output work that causes rotation of the spool of the gas turbine engine
Wasselin teaches (Figures 1-3C) causing, during an emergency restart operation, a starter to output work that causes rotation of the spool of the gas turbine engine (see abstract and Figure 3C).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Veilleux in view of Hon to cause, during the emergency restart operation, a starter to output work that causes rotation of the spool of the gas turbine engine, as taught by Wasselin, in order to restart an engine of an aircraft during a flight of the aircraft (see abstract of Wasselin). Veilleux in view of Hon and Wasselin does not teach the first initial fuel flow rate and the second initial fuel flow rate are configured to cause an air:fuel ratio to be equal or causing both an electric machine and an air turbine starter to output work that causes rotation of the spool of the gas turbine engine.
Thompson teaches (Figure 1) causing both (see abstract, Paragraph 0005, and Paragraph 0011) an electric machine (8) and an air starter (6) to output work that causes rotation of the spool of the gas turbine engine (4).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Veilleux in view of Hon and Wasselin to cause both an electric machine and an air turbine starter to output work that causes rotation of the spool of the gas turbine engine, as taught by Thompson, in order to maximize power delivered for starting propulsion engines by combining power sources so that essentially the entire power delivered for pneumatic, hydraulic, and electric power is applied to start (see Paragraph 0005 of Thompson). Veilleux in view of Hon, Wasselin, and Thompson does not teach the first initial fuel flow rate and the second initial fuel flow rate are configured to cause an air:fuel ratio to be equal.
Fitzgerald teaches (Paragraphs 0003 and 0038) that an equivalence ratio (a ratio of air to fuel in the air-fuel mixture being combusted in the combustion chamber; see Paragraph 0038) being too low or too high can result in flame blowout, over-firing, hardware distress, a reduction in component life of the combustion system, and/or a potential for power outage (Paragraph 0003). Therefore, the ratio of air to fuel being combusted in the combustion chamber is recognized as a result-effective variables, i.e. a variable which achieves a recognized result. In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977); MPEP 2144.05(II)(B). In this case, the recognized result is that increasing the air to fuel ratio too high results in over-firing and decreasing the air to fuel ratio too low results in flame blowout, which leads to undesired combustion dynamics causing hardware distress and a reduction in component life (see Paragraph 0003 of Fitzgerald).
Therefore, since the general conditions of the claim, i.e. that the ratio of air to fuel delivered to the combustor should be controlled so that it is not too high or too low, were disclosed in the prior art by Fitzgerald, it is not inventive to discover the optimum workable range by routine experimentation, and it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to provide the equivalence ratios as taught by Fitzgerald in order to avoid flame blowout, over-firing, undesired dynamics, reduction in component life, and power outage. It has been held that “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955); MPEP 2144.05(II)(A).
Regarding Claim 12, Veilleux in view of Hon, Wasselin, Thompson, and Fitzgerald teaches the invention as claimed and as discussed above. Veilleux further teaches (Figures 1-4) wherein introducing fuel at the second rotational speed (see Paragraph 0041) results in a turbine temperature that is above a critical turbine temperature of the turbine (due to an insufficient amount of airflow that is provided through the turbomachine to cool the turbomachine once re-ignition is initiated, which would reduce an exhaust gas temperature during restart).
It is noted that Hon teaches (Figures 1-9) wherein introducing fuel at the second rotational speed results in a turbine temperature that is above a critical turbine temperature of the turbine (Paragraphs 0006, 0049, and 0106 of Hon).
Regarding Claim 13, Veilleux in view of Hon, Wasselin, Thompson, and Fitzgerald teaches the invention as claimed and as discussed above. Veilleux further teaches (Figures 1-4) wherein operation of the turbine above the critical temperature reduces a lifetime of the turbine (due to an insufficient amount of airflow that is provided through the turbomachine to cool the turbomachine once re-ignition is initiated, which would reduce an exhaust gas temperature during restart).
It is noted that Hon teaches (Figures 1-9) wherein operation of the turbine above the critical temperature reduces a lifetime of the turbine (decreasing a lifespan of the components within the engine due to elevated internal temperatures; see Paragraph 0006 of Hon).
Regarding Claim 14, Veilleux in view of Hon, Wasselin, Thompson, and Fitzgerald teaches the invention as claimed and as discussed above. Veilleux further teaches (Figures 1-4) wherein the second threshold rotational speed is at least 10% lower than the first threshold speed (the first threshold speed is 15 percent of the rated speed and the second threshold speed is 5 percent of the rated speed; see Paragraphs 0041).
Regarding Claim 17, Veilleux in view of Hon, Wasselin, Thompson, and Fitzgerald teaches the invention as claimed and as discussed above. Veilleux further teaches (Figures 1-4) wherein the second threshold rotational speed is at least 10% lower than the first threshold speed (the first threshold speed is 15 percent of the rated speed and the second threshold speed is 5 percent of the rated speed; see Paragraph 0041).
Regarding Claim 20, Veilleux in view of Hon, Wasselin, Thompson, and Fitzgerald teaches the invention as claimed and as discussed above. Veilleux further teaches (Figures 1-4) wherein the second initial fuel flow rate (a windmilling output rate of 5% of a rated engine speed; see Paragraph 0041) is lower (due to the fuel pump being a gear pump driven by the engine accessory gearbox; see Figure 1 and Paragraph 0026) than the first initial fuel flow rate (a normal starting speed of 15% rated engine speed; see Paragraph 0041).
Claims 15 is rejected under 35 U.S.C. 103 as being unpatentable over Veilleux (US 2018/0045122) in view of Hon et al. (US 2018/0354632), Wasselin (US 2024/0003300), Thompson (US 2006/0032234), and Fitzgerald et al. (US 2014/0238032) as applied to claim 11 above, and further in view of Smith, JR. et al. (US 2022/0106059).
Regarding Claim 15, Veilleux in view of Hon, Wasselin, Thompson, and Fitzgerald teaches the invention as claimed and as discussed above. Veilleux further teaches (Figures 1-4) wherein introducing fuel at the second rotational speed (see Paragraph 0041) results in a turbine temperature that is above a critical turbine temperature of the turbine (due to an insufficient amount of airflow that is provided through the turbomachine to cool the turbomachine once re-ignition is initiated, which would reduce an exhaust gas temperature during restart). It is noted that Hon also teaches (Figures 1-9) wherein introducing fuel at the second rotational speed results in a turbine temperature that is above a critical turbine temperature of the turbine (Paragraphs 0006, 0049, and 0106 of Hon). Veilleux in view of Hon, Wasselin, Thompson, and Fitzgerald does not teach wherein the controller is further configured: to generate a data record indicating that the temperature of the turbine has exceeded a temperature threshold.
Smith teaches (Figures 1-24) computing devices receiving sensor data and recording parameters such as exhaust gas temperature when an exhaust gas temperature threshold is exceeded (Paragraph 0204).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Veilleux in view of Hon, Wasselin, Thompson, and Fitzgerald to have the controller generate a data record indicating the temperature of the exhaust gas has exceeded a temperature threshold, as taught by Smith, in order to determine the cause of an unexpected behavior if the engine performs in an unexpected way (Paragraph 0003 of Smith).
Claims 6 and 16 are rejected under 35 U.S.C. 103 as being unpatentable over Veilleux (US 2018/0045122) in view of Hon et al. (US 2018/0354632) and Fitzgerald et al. (US 2014/0238032) as applied to claims 1 and 11, and further in view of Trivedi et al. (US 2023/0417148).
Regarding Claim 16, Veilleux in view of Hon, Wasselin, Thompson, and Fitzgerald teaches the invention as claimed and as discussed above. Veilleux further teaches (Figures 1-4) that the fuel pump (110) is a gear pump that can be driven by the engine accessory gearbox, the accessory gearbox mechanically coupled to the high pressure spool of the engine (see Paragraphs 0024-0026) and the starter speed set about 15% of an engine speed during the nominal ground-based starting (Paragraph 0041). Veilleux in view of Hon, Wasselin, Thompson, and Fitzgerald does not teach that this rotational speed is from about 10% to about 40% of a cruising rotational speed, i.e., the cruising speed is between about 25% rated speed and about 100% rated speed.
Trivedi teaches that a turbine engine utilized to power an aircraft may exhibit cruise operating conditions at a rotational speed that is from about 50% to about 90% of the rated speed (Paragraph 0042).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Veilleux in view of Hon, Wasselin, Thompson, and Fitzgerald to have the cruising speed be between 25% rated speed and 100% rated speed, as taught by Trivedi, in order to operate the engine at a relatively high rotational speed for a sustained period of time after a climb phase and prior to descending to an approach phase (Paragraphs 0035 and 0042 of Trivedi).
Claim 21 is rejected under 35 U.S.C. 103 as being unpatentable over Veilleux (US 2018/0045122) in view of Hon et al. (US 2018/0354632), Wasselin (US 2024/0003300), Thompson (US 2006/0032234), Finney et al. (US 2012/0221157) and Fitzgerald et al. (US 2014/0238032).
Regarding Independent Claim 21, Veilleux teaches (Figures 1-4) a starting apparatus (see Figure 1) for a gas turbine engine (10) of an aircraft (see Figure 1 and Paragraph 0002), the starting apparatus (see Figure 1) comprising:
a fuel supply system (100);
a spool (30 or 32);
a combustor (18);
a starter (50, which can be an electric or pneumatic starter; see Paragraph 0024) configured to cause rotation of the spool (see Paragraph 0024);
a propulsor (12);
a controller (130) configured to:
cause fuel (from 110) to be introduced (via 112, 154) to the combustor (18) of the gas turbine engine (10) at a first threshold rotational speed of the gas turbine engine during a normal starting operation in which the aircraft is on the ground (nominal ground-based engine starting speed of about 15%; see Paragraph 0041); and
cause fuel (from 110) to be introduced (via 112, 154) into the combustor (18) at a second threshold rotational speed of the gas turbine engine during an emergency in-flight restarting operation in which the aircraft is in-flight (a speed of about 5% set to model a windmilling condition for an in-flight restart; see Paragraph 0041),
wherein the second threshold rotational speed is lower than the first threshold rotational speed (see Paragraph 0041) such that fuel is introduced earlier during the emergency in-flight restart than fuel is introduced during the normal starting operation (due to the fuel being introduced when the speed reaches about 5% of the engine speed during the second threshold and the fuel being introduced when the speed reaches about 15% of the engine speed during the first threshold; see Paragraph 0041),
introducing fuel at the second threshold rotational speed (Paragraph 0041) results in a higher temperature in a turbine of the gas turbine engine (due to introducing fuel earlier in the spool-up process, resulting in higher temperatures in the combustor) than introducing fuel at the first threshold rotational speed (the first threshold speed of about 15% and the second threshold speed of about 5%; see Paragraph 0041),
the controller (130) is configured to introduce (via 112, 154) fuel (from 110) at a first initial fuel flow rate during the normal starting operation (a required fuel flow to satisfy a stoichiometric fuel-air ratio to achieve light-off; see Paragraph 0041),
the controller (130) is configured to introduce (via 112, 154) fuel (from 110) at a second initial fuel flow rate during the emergency in-flight restarting operation (a required fuel flow to satisfy a stoichiometric fuel-air ratio to achieve light-off; see Paragraph 0041)
introducing fuel at the second rotational speed (see Paragraph 0041) results in a turbine temperature that is above a critical turbine temperature of the turbine (due to an insufficient amount of airflow that is provided through the turbomachine to cool the turbomachine once re-ignition is initiated, which would reduce an exhaust gas temperature during restart), and
operation of the turbine above the critical temperature reduces a lifetime of the turbine (due to an insufficient amount of airflow that is provided through the turbomachine to cool the turbomachine once re-ignition is initiated, which would reduce an exhaust gas temperature during restart).
Veilleux does not teach a plurality of gas turbine engines of an aircraft, causing both an electric starter and an air turbine starter to cause rotation of the spool during an in-flight restarting operation in which the aircraft is in-flight, causing an electrical generator to generate electrical power through a windmilling operation of the propulsor and route the generated electrical power to the electric starter, or the first initial fuel flow rate and the second initial fuel flow rate are configured to cause an air:fuel ratio to be substantially similar.
Hon teaches (Figures 1-9) that a conventional commercial aircraft includes a fuselage, a pair of wings, and a propulsion system that typically includes at least two aircraft engines, such as turbofan jet engines (Paragraph 0002).
It is noted that Hon also teaches (Figures 1-9) wherein introducing fuel at the second rotational speed results in a turbine temperature that is above a critical turbine temperature of the turbine (Paragraphs 0006, 0049, and 0106 of Hon) and that wherein operation of the turbine above the critical temperature reduces a lifetime of the turbine (decreasing a lifespan of the components within the engine due to elevated internal temperatures; see Paragraph 0006 of Hon).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Veilleux to include the plurality of gas turbine engines of an aircraft, as taught by Hon, in order to provide thrust (Paragraph 0002 of Hon). Veilleux in view of Hon does not teach causing both an electric starter and an air turbine starter to cause rotation of the spool during an in-flight restarting operation in which the aircraft is in-flight, causing an electrical generator to generate electrical power through a windmilling operation of the propulsor and route the generated electrical power to the electric starter, or the first initial fuel flow rate and the second initial fuel flow rate are configured to cause an air:fuel ratio to be substantially similar.
Wasselin teaches (Figures 1-3C) causing, during an emergency restart operation, a starter to output work that causes rotation of the spool of the gas turbine engine (see abstract and Figure 3C).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Veilleux in view of Hon to cause, during the emergency restart operation, a starter to output work that causes rotation of the spool of the gas turbine engine, as taught by Wasselin, in order to restart an engine of an aircraft during a flight of the aircraft (see abstract of Wasselin). Veilleux in view of Hon and Wasselin does not teach causing both an electric starter and an air turbine starter to cause rotation of the spool, causing an electrical generator to generate electrical power through a windmilling operation of the propulsor and route the generated electrical power to the electric starter, or the first initial fuel flow rate and the second initial fuel flow rate are configured to cause an air:fuel ratio to be substantially similar.
Thompson teaches (Figure 1) causing both (see abstract, Paragraph 0005, and Paragraph 0011) an electric machine (8) and an air starter (6) to output work that causes rotation of the spool of the gas turbine engine (4).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Veilleux in view of Hon and Wasselin to cause both an electric machine and an air turbine starter to output work that causes rotation of the spool of the gas turbine engine, as taught by Thompson, in order to maximize power delivered for starting propulsion engines by combining power sources so that essentially the entire power delivered for pneumatic, hydraulic, and electric power is applied to start (see Paragraph 0005 of Thompson). Veilleux in view of Hon, Wasselin, and Thompson does not teach causing an electrical generator to generate electrical power through a windmilling operation of the propulsor and route the generated electrical power to the electric starter, or the first initial fuel flow rate and the second initial fuel flow rate are configured to cause an air:fuel ratio to be substantially similar.
Finney teaches (Figures 1-3) an electrical generator (48) that is caused to generate electrical power through a windmilling operation of the propulsor (36) and route the generated electrical power to an electrical starter (see Paragraph 0012).
It It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Veilleux in view of Hon, Wasselin, and Thompson to cause an electrical generator to generate electrical power through a windmilling operation of the propulsor and route the generated electrical power to the electric starter, as taught by Finney, in order to generate electrical energy during an emergency in which the gas turbine engine fails to operate normally (Paragraph 0012 of Finney). It is noted that Hon also teaches that higher threshold speeds result in more airflow provided through the turbomachine to cool the turbomachine once the re-ignition is initiated, thereby reducing the exhaust gas temperature (see Paragraph 0049 of Hon). Veilleux in view of Hon, Wasselin, Thompson, and Finney does not teach the first initial fuel flow rate and the second initial fuel flow rate are configured to cause an air:fuel ratio to be substantially similar
Fitzgerald teaches (Paragraphs 0003 and 0038) that an equivalence ratio (a ratio of air to fuel in the air-fuel mixture being combusted in the combustion chamber; see Paragraph 0038) being too low or too high can result in flame blowout, over-firing, hardware distress, a reduction in component life of the combustion system, and/or a potential for power outage (Paragraph 0003). Therefore, the ratio of air to fuel being combusted in the combustion chamber is recognized as a result-effective variables, i.e. a variable which achieves a recognized result. In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977); MPEP 2144.05(II)(B). In this case, the recognized result is that increasing the air to fuel ratio too high results in over-firing and decreasing the air to fuel ratio too low results in flame blowout, which leads to undesired combustion dynamics causing hardware distress and a reduction in component life (see Paragraph 0003 of Fitzgerald).
Therefore, since the general conditions of the claim, i.e. that the ratio of air to fuel delivered to the combustor should be controlled so that it is not too high or too low, were disclosed in the prior art by Fitzgerald, it is not inventive to discover the optimum workable range by routine experimentation, and it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to provide the equivalence ratio as taught by Fitzgerald in order to avoid flame blowout, over-firing, undesired dynamics, reduction in component life, and power outage. It has been held that “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955); MPEP 2144.05(II)(A).
Response to Arguments
Applicant’s arguments with respect to claims 1-8, 10-17, and 20-21 have been considered but are moot because the arguments do not apply to the new combination of references being applied in this office action, necessitated by amendment. However, to the extent possible, Applicant’s arguments are addressed in the body of the rejection above, at the appropriate locations.
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/THOMAS P BURKE/Primary Examiner, Art Unit 3741
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