DETAILED ACTION
This is in response to the Amendment filed 12/29/2025 wherein claims 19 and 21 are canceled and claims 1-18 and 20 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 .
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 (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.
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 1-2, 5-9, and 11-17 are rejected under 35 U.S.C. 103 as being unpatentable over Bacic et al. (US 2015/0247417) in view of Schelfaut (US 2018/0258785), Lewis (US 2014/0321985), and Philbrick et al. (US 2017/0292399).
Regarding Independent Claim 1, Bacic ‘417 teaches (Figures 1-9) a gas turbine engine (10) comprising:
a first component (42);
a second component (38) rotatable (Paragraphs 0042-0043) relative to the first component (42), wherein a clearance (44; see Figure 3) is defined between the first component (42) and the second component (38); and
an engine controller (74) having one or more processors (78), the one or more processors (78) are configured to:
operate the gas turbine engine (10) in a first flight condition (a cruise phase of the flight; see Paragraph 0050 and Figures 4-5);
receive a demand for a second flight condition (a step-climb phase of the flight; see Paragraph 0051 and Figures 4-5) that is different than the first flight condition (a cruise phase of the flight; see Paragraph 0050 and Figures 4-5);
determine a target clearance (60) between the first component (42) and the second component (38), the target clearance (60) associated with the second flight condition (a step-climb phase of the flight; see Paragraph 0051 and Figures 4-5);
adjust an engine acceleration rate to a nominal acceleration rate (Paragraph 0067);
compare (at 100; see Paragraph 0064) an actual clearance (94) with the target clearance (60) after one or more pre-determined increments of time (a fixed iteration rate, for example every 100-1000ms; see Paragraph 0056); and
adjust the engine acceleration rate based on the comparison (at 100) between the actual clearance (94) and the target clearance (94), wherein the target clearance (94) is adjusted at least partially based on the adjustment to the engine acceleration rate (Paragraph 0067).
Bacic ‘417 does not teach determining an initial target clearance, a final target clearance, an intermediate target clearance, and a plurality of transient target clearances, initiating a transition between the first flight condition and the second flight condition, wherein adjusting at least one of the plurality of transient target clearances is continuous, wherein adjusting at least one of the plurality of transient target clearances comprises recalculating, by the engine controller, at least one transient target clearance of the plurality of transient target clearances at each of the one or more pre-determined increments of time during the transition, and wherein the one or more pre-determined increments of time correspond to a rate of recalculation of the engine controller, such that the at least one transient target clearance is iteratively updated throughout the transition, or determining whether an actual clearance is consistent with each of the plurality of transient target clearances during the transition by determining whether the actual clearance is within a predetermined margin of a respective transient target clearance of the plurality of transient target clearances at an instance in time, and adjust or maintain the clearance control based on determining whether the actual clearance is consistent with the plurality of transient target clearances during the transition to achieve at least one of the intermediate target clearance or the final target clearance.
Schelfaut teaches (Figures 1-13) a schedule of clearance targets as a function of core speed (see Figure 4 and Paragraphs 0067-0068), the schedule of clearance targets includes an initial target clearance (a target clearance along model 270 as a function of the core speed corresponding to the end of a first flight condition, e.g. a cruise phase of flight; see Figures 4 and 7), a final target clearance (a target clearance along model 270 as a function of the core speed corresponding to the beginning of the second flight condition, e.g., a step-climb phase of flight; see Figures 4 and 7), an intermediate target clearance (a target clearance along model 270 as a function of the core speed between the initial target clearance and the final target clearance; see Figures 4 and 7), and a plurality of transient target clearances (target clearances along model 270 as a function of the core speed during a transition period 370, 372; see Figures 4, 7, 11, and Paragraph 0110), initiating a transition (370, 372) between the first flight condition (a cruise phase of flight; see Figures 7, 11, and 0110) and the second flight condition (a step-climb phase of flight; see Figures 7, 11, and Paragraph 0110), a schedule of core speed as a function of flight mission time (see Figure 7 and Paragraph 0094-0095), comparing (at 286), during the transition, the actual clearance with the plurality of transient target clearances (the machine-learned model 290 outputs adjusted clearance control targets for the entire time in which the aircraft is expected to be in the air; see Paragraph 0083), wherein adjusting at least one of the plurality of transient target clearances is continuous (the blade tip clearance target model includes a machine-learned model trained to adjust the model blade tip clearance targets based at least in part on how an engine has been uniquely operated for a particular flight mission by obtaining present flight data, present flight conditions, and present operating parameters during a flight, which may be continuously updated over the course of a flight; see Paragraphs 0082-0083).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Bacic ‘417 to include the determination of an initial target clearance, a final target clearance, an intermediate target clearance, and a plurality of transient target clearances, initiating a transition between the first flight condition and the second flight condition, wherein adjusting at least one of the plurality of transient target clearances is continuous, as taught by Schelfaut, in order to allow an acceleration to be completed from any given speed of the engine to a maximum continuous speed and to adjust the tip clearance targets based on present flight data (Paragraphs 0067 and 0082 of Schelfaut). Bacic ‘417 in view of Schelfaut does not teach, as discussed so far, wherein adjusting at least one of the plurality of transient target clearances comprises recalculating, by the engine controller, at least one transient target clearance of the plurality of transient target clearances at each of the one or more pre-determined increments of time during the transition, and wherein the one or more pre-determined increments of time correspond to a rate of recalculation of the engine controller, such that the at least one transient target clearance is iteratively updated throughout the transition or determining whether an actual clearance is consistent with a target clearance by determining whether the actual clearance is within a predetermined margin of the target clearance at an instance in time, and adjust or maintain the clearance control based on determining whether the actual clearance is consistent with the target clearance to achieve the target clearance.
Lewis teaches (Figures 1-11) adjusting at least one of a plurality of transient target clearances (due to transient thermal growth of each component; see Paragraphs 0086-0088) comprises recalculating (in step 94), by an engine controller (80), at least one transient target clearance (44) of the plurality of transient target clearances (44) at each of the one or more pre-determined increments of time (tn; time steps) during the transition (Paragraph 0097), and wherein the one or more pre-determined increments of time (tn) correspond to a rate of recalculation of the engine controller (80; time steps are similar to the measurement frequency of control parameters and within the processing capacity of the controller and the measurement and calculation periods are matched to the frequency at which the clearance arrangement can act to change the clearance; see Paragraph 0092), such that the at least one transient target clearance (44) is iteratively updated throughout the transition (see Figure 11 and Paragraph 0092).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Bacic ‘417 in view of Schelfaut to adjust at least one of the plurality of transient target clearances by recalculating, by the engine controller, at least one transient target clearance of the plurality of transient target clearances at each of the one or more pre-determined increments of time during the transition, and wherein the one or more pre-determined increments of time correspond to a rate of recalculation of the engine controller, such that the at least one transient target clearance is iteratively updated throughout the transition, as taught by Lewis, in order to have the time steps at the low end of a range of 0.1 to 10 seconds so that the measurement frequency of control parameters is within the processing capacity of the suitable controllers and to match the measurement and calculation periods to the frequency at which the clearance arrangement can act to change the clearance (Paragraph 0092 of Lewis). Bacic ‘417 in view of Schelfaut and Lewis does not teach, as discussed so far, determining whether an actual clearance is consistent with a target clearance by determining whether the actual clearance is within a predetermined margin of the target clearance at an instance in time, and adjust or maintain the clearance control based on determining whether the actual clearance is consistent with the target clearance to achieve the target clearance.
Philbrick teaches (Figures 1-5) determining whether an actual clearance is consistent with a target clearance by determining whether the actual clearance is within a predetermined margin of the transient target clearance at an instance in time (at 530, where the actual clearance is determined using real-time data from 518; see Figure 5 and Paragraph 0036-0038), and adjust or maintain the clearance control (to 536 or to 518; see Figure 5 and Paragraph 0038) based on determining whether the actual clearance is consistent with the transient target clearance to achieve the target clearance (at 530; see Figure 5).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Bacic ‘417 in view of Schelfaut and Lewis to determine whether an actual clearance is consistent with a target clearance by determining whether the actual clearance is within a predetermined margin of the target clearance at an instance in time, and adjust or maintain the clearance control based on determining whether the actual clearance is consistent with the target clearance to achieve the target clearance, as taught by Philbrick, in order to provide enhanced protection of structures of an aircraft engine during various speed/power conditions and to ensure that a minimum clearance between an engine case and a turbine section of the engine is maintained over the operative envelope of the engine to enhance the useable lifetime of the engine case and the turbine section while at the same time ensuring that the clearance does not exceed a maximum value so as to promote engine performance/efficiency (Paragraph 0040 of Philbrick).
Regarding Claim 2, Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick teaches the invention as claimed and as discussed above. Bacic ‘417 teaches (Figures 1-9) wherein, in comparing the actual clearance (94) with the target clearances (60), one or more processors (78) are further configured to: adjust the engine acceleration rate (Paragraph 0067) when the actual clearance (94) is not within the predetermined margin (70, 72) of the target clearance (60).
As discussed above, although Bacic ‘417 does not teach determining transient target clearances, Schelfaut teaches (Figures 1-13) a schedule of clearance targets as a function of core speed (see Figure 4 and Paragraphs 0067-0068) and a schedule of core speed as a function of flight mission time (see Figure 7 and Paragraph 0094-0095).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick to include the plurality of clearance targets associated with the flight mission, as taught by Schelfaut, for the reasons discussed above in claim 1.
Regarding Claim 5, Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick teaches the invention as claimed and as discussed above. Bacic ‘417 further teaches that “the processor 78 may be configured to determine the engine power demand at a fixed iteration rate, for example every 100-1000 ms” (see Paragraph 0056). As discussed above, although Bacic ‘417 does not teach determining a final target clearance and a transient target clearance, Schelfaut teaches (Figures 1-13) a schedule of clearance targets as a function of core speed (see Figure 4 and Paragraphs 0067-0068) and a schedule of core speed as a function of flight mission time (see Figure 7 and Paragraph 0094-0095). Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick does not teach, as discussed so far, wherein the one or more processors are further configured to: repeat a comparison between the actual clearance and the transient target clearances and the adjustment of the engine acceleration rate based on the comparison after the increment of time until the actual clearance is within a predetermined acceptable range of the final target clearance.
Schelfaut teaches (Figures 1-13) wherein one or more processors (212) are configured to repeat a comparison (at 274 in Figure 4 and 286 in Figure 5) between the actual clearance (272) and the transient target clearances (270) and the adjustment of an engine acceleration rate (264) based on the comparison (274, 286) after the increment of time until the actual clearance (272) is within a predetermined acceptable range (342) of a final target clearance (280).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick to have the one or more processors be configured to repeat a comparison between the actual clearance and the transient target clearance and the adjustment of the engine acceleration rate based on the comparison after the increment of time until the actual clearance is within a predetermined acceptable range of the final target clearance, as taught by Schelfaut, in order to allow an acceleration to be completed from any given speed of the engine to a maximum continuous speed (Paragraph 0067 of Schelfaut).
Regarding Claim 6, Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick teaches the invention as claimed and as discussed above. Bacic ‘417 further teaches that “the processor 78 repeatedly determines the engine power demand each time a new measurement is provided by the sensor 76 or one of the sensors 76” or “the processor 78 may be configured to determine the engine power demand at a fixed iteration rate, for example every 100-1000 ms” (see Paragraph 0056). As discussed above, although Bacic ‘417 does not teach determining a final target clearance and a transient target clearance, Schelfaut teaches (Figures 1-13) a schedule of clearance targets as a function of core speed (see Figure 4 and Paragraphs 0067-0068) and a schedule of core speed as a function of flight mission time (see Figure 7 and Paragraph 0094-0095). Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick does not teach, as discussed so far, wherein the one or more processors are further configured to: repeat the comparison between the actual clearance and the transient target clearances and the adjustment of the engine acceleration rate based on the comparison after the increment of time until the gas turbine engine is operating in the second flight condition.
Schelfaut teaches (Figures 1-13) wherein one or more processors (212) are configured to repeat a comparison (at 274 in Figure 4 and 286 in Figure 5) between the actual clearance (272) and the transient target clearances (270) and the adjustment of an engine acceleration rate (264) based on the comparison (274, 286) after the increment of time until the gas turbine engine (100) is operating in the second flight condition (a condition corresponding to a core speed of a different flight phase; see Figure 7).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick to have the one or more processors be configured to repeat a comparison between the actual clearance and the transient target clearances and the adjustment of the engine acceleration rate based on the comparison after the increment of time until the gas turbine engine is operating in the second flight condition, as taught by Schelfaut, in order to allow an acceleration to be completed from any given speed of the engine to a maximum continuous speed (Paragraph 0067 of Schelfaut).
Regarding Claim 7, Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick teaches the invention as claimed and as discussed above. Bacic ‘417 further teaches (Figures 1-9)wherein the one or more processors (78) are further configured to: receive data (via sensors 76) indicating the actual clearance (Paragraphs 0061-0062) between the first component (42) and the second component (38), the actual clearance (Paragraphs 0061-0062) being a calculated clearance specific to the gas turbine engine at that point in time (94; see Paragraph 0062).
Regarding Claim 8, Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick teaches the invention as claimed and as discussed above. As discussed above, although Bacic ‘417 does not teach determining a final target clearance and a transient target clearance, Schelfaut teaches (Figures 1-13) a schedule of clearance targets as a function of core speed (see Figure 4 and Paragraphs 0067-0068) and a schedule of core speed as a function of flight mission time (see Figure 7 and Paragraph 0094-0095). Bacic ‘417 further teaches (Figures 1-9) a clearance adjustment system (at 104, opening or closing a valve to supply or cut off cooling air to portions of the rotor stage casing 42 or segment assembly 56; see Paragraph 0064) configured to adjust the clearance between the first component (42) and the second component (38), and wherein the one or more processors (78) are further configured to: cause the clearance adjustment system (at 104) to adjust the clearance based the comparison (at 100) between the actual clearance (94) and the target clearances (60).
Regarding Claim 9, Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick teaches the invention as claimed and as discussed above. As discussed above, although Bacic ‘417 does not teach determining a final target clearance and a transient target clearance, Schelfaut teaches (Figures 1-13) a schedule of clearance targets as a function of core speed (see Figure 4 and Paragraphs 0067-0068) and a schedule of core speed as a function of flight mission time (see Figure 7 and Paragraph 0094-0095). Bacic ‘417 further teaches (Figures 1-9) wherein the target clearance (60) is adjusted each time the engine acceleration rate is adjusted (at 92).
Regarding Claim 11, Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick teaches the invention as claimed and as discussed above. Bacic ‘417 further teaches (Figures 1-9) wherein the first flight condition comprises a steady-state cruise condition (a cruise phase of the flight; see Paragraph 0050 and Figures 4-5), and wherein the second flight condition comprises a step-climb condition (a step-climb phase of the flight; see Paragraph 0051 and Figures 4-5).
Regarding Independent Claim 12, Bacic ‘417 teaches (Figures 1-9) a non-transitory computer readable medium comprising computer-executable instructions (Paragraphs 0019 and 0068), which, when executed by one or more processors (78) of a computing system (74) associated with a gas turbine engine (10), cause the one or more processors (78) to:
operate the gas turbine engine (10) in a first flight condition (a cruise phase of the flight; see Paragraph 0050 and Figures 4-5);
receive data (from 76) indicating an actual clearance (94) between a first component (42) of the gas turbine engine (10) and a second component (38) of the gas turbine engine (10), the second component (38) being rotatable (Paragraphs 0042-0043) relative to the first component (42), the actual clearance (94) being at least one of a measured clearance captured by a sensor and a calculated clearance specific to the gas turbine engine at that point in time (94; see Paragraph 0062);
receive a demand for a second flight condition (a step-climb phase of the flight; see Paragraph 0051 and Figures 4-5) that is different than the first flight condition (a cruise phase of the flight; see Paragraph 0050 and Figures 4-5);
determine a target clearance (60) between the first component (42) and the second component (38), the target clearance (60) associated with the second flight condition (a step-climb phase of the flight; see Paragraph 0051 and Figures 4-5);
adjust an engine acceleration rate to a nominal acceleration rate (Paragraph 0067);
compare (at 100; see Paragraph 0064) an actual clearance (60) with the target clearance (94) after one or more pre-determined increments of time (a fixed iteration rate, for example every 100-1000ms; see Paragraph 0056); and
adjust the engine acceleration rate based on the comparison (at 100) between the actual clearance (94) and the target clearance (94), wherein the target clearance (94) is adjusted at least partially based on the adjustment to the engine acceleration rate (Paragraph 0067).
Bacic ‘417 does not teach determining a final target clearance, an intermediate target clearance, and a plurality of transient target clearances, initiating a transition between the first flight condition and the second flight condition, wherein adjusting at least one of the plurality of transient target clearances is continuous, wherein adjusting at least one of the plurality of transient target clearances comprises recalculating, by the computing system, at least one transient target clearance of the plurality of transient target clearances at each of the one or more pre-determined increments of time during the transition, and wherein the one or more pre-determined increments of time correspond to a rate of recalculation of the computing system, such that the at least one transient target clearance is iteratively updated throughout the transition, or determining whether an actual clearance is consistent with each of the plurality of transient target clearances during the transition by determining whether the actual clearance is within a predetermined margin of a respective transient target clearance of the plurality of transient target clearances at an instance in time, and adjust or maintain the clearance control based on determining whether the actual clearance is consistent with the plurality of transient target clearances during the transition to achieve at least one of the intermediate target clearance or the final target clearance.
Schelfaut teaches (Figures 1-13) a schedule of clearance targets as a function of core speed (see Figure 4 and Paragraphs 0067-0068), the schedule of clearance targets includes a final target clearance (a target clearance along model 270 as a function of the core speed corresponding to the beginning of the second flight condition, e.g., a step-climb phase of flight; see Figures 4 and 7), an intermediate target clearance (a target clearance along model 270 as a function of the core speed between the initial target clearance and the final target clearance; see Figures 4 and 7), and a plurality of transient target clearances (target clearances along model 270 as a function of the core speed during a transition period 370, 372; see Figures 4, 7, 11, and Paragraph 0110), initiating a transition (370, 372) between the first flight condition (a cruise phase of flight; see Figures 7, 11, and 0110) and the second flight condition (a step-climb phase of flight; see Figures 7, 11, and Paragraph 0110), a schedule of core speed as a function of flight mission time (see Figure 7 and Paragraph 0094-0095), comparing (at 286), during the transition, the actual clearance with the plurality of transient target clearances (the machine-learned model 290 outputs adjusted clearance control targets for the entire time in which the aircraft is expected to be in the air; see Paragraph 0083), wherein adjusting at least one of the plurality of transient target clearances is continuous (the blade tip clearance target model includes a machine-learned model trained to adjust the model blade tip clearance targets based at least in part on how an engine has been uniquely operated for a particular flight mission by obtaining present flight data, present flight conditions, and present operating parameters during a flight, which may be continuously updated over the course of a flight; see Paragraphs 0082-0083).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Bacic ‘417 to include the determination of an initial target clearance, a final target clearance, an intermediate target clearance, and a plurality of transient target clearances, initiating a transition between the first flight condition and the second flight condition, wherein adjusting at least one of the plurality of transient target clearances is continuous, as taught by Schelfaut, in order to allow an acceleration to be completed from any given speed of the engine to a maximum continuous speed and to adjust the tip clearance targets based on present flight data (Paragraphs 0067 and 0082 of Schelfaut). Bacic ‘417 in view of Schelfaut does not teach, as discussed so far, wherein adjusting at least one of the plurality of transient target clearances comprises recalculating, by the computing system, at least one transient target clearance of the plurality of transient target clearances at each of the one or more pre-determined increments of time during the transition, and wherein the one or more pre-determined increments of time correspond to a rate of recalculation of the computing system, such that the at least one transient target clearance is iteratively updated throughout the transition or determining whether an actual clearance is consistent with a target clearance by determining whether the actual clearance is within a predetermined margin of the target clearance at an instance in time, and adjust or maintain the clearance control based on determining whether the actual clearance is consistent with the target clearance to achieve the target clearance.
Lewis teaches (Figures 1-11) adjusting at least one of a plurality of transient target clearances (due to transient thermal growth of each component; see Paragraphs 0086-0088) comprises recalculating (in step 94), by a computing system (80), at least one transient target clearance (44) of the plurality of transient target clearances (44) at each of the one or more pre-determined increments of time (tn; time steps) during the transition (Paragraph 0097), and wherein the one or more pre-determined increments of time (tn) correspond to a rate of recalculation of the computing system (80; time steps are similar to the measurement frequency of control parameters and within the processing capacity of the controller and the measurement and calculation periods are matched to the frequency at which the clearance arrangement can act to change the clearance; see Paragraph 0092), such that the at least one transient target clearance (44) is iteratively updated throughout the transition (see Figure 11 and Paragraph 0092).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Bacic ‘417 in view of Schelfaut to adjust at least one of the plurality of transient target clearances by recalculating, by the computing system, at least one transient target clearance of the plurality of transient target clearances at each of the one or more pre-determined increments of time during the transition, and wherein the one or more pre-determined increments of time correspond to a rate of recalculation of the computing system, such that the at least one transient target clearance is iteratively updated throughout the transition, as taught by Lewis, in order to have the time steps at the low end of a range of 0.1 to 10 seconds so that the measurement frequency of control parameters is within the processing capacity of the suitable controllers and to match the measurement and calculation periods to the frequency at which the clearance arrangement can act to change the clearance (Paragraph 0092 of Lewis). Bacic ‘417 in view of Schelfaut and Lewis does not teach, as discussed so far, determining whether an actual clearance is consistent with a target clearance by determining whether the actual clearance is within a predetermined margin of the target clearance at an instance in time, and adjust or maintain the clearance control based on determining whether the actual clearance is consistent with the target clearance to achieve the target clearance.
Philbrick teaches (Figures 1-5) determining whether an actual clearance is consistent with a target clearance by determining whether the actual clearance is within a predetermined margin of the transient target clearance at an instance in time (at 530, where the actual clearance is determined using real-time data from 518; see Figure 5 and Paragraph 0036-0038), and adjust or maintain the clearance control (to 536 or to 518; see Figure 5 and Paragraph 0038) based on determining whether the actual clearance is consistent with the transient target clearance to achieve the target clearance (at 530; see Figure 5).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Bacic ‘417 in view of Schelfaut and Lewis to determine whether an actual clearance is consistent with a target clearance by determining whether the actual clearance is within a predetermined margin of the target clearance at an instance in time, and adjust or maintain the clearance control based on determining whether the actual clearance is consistent with the target clearance to achieve the target clearance, as taught by Philbrick, in order to provide enhanced protection of structures of an aircraft engine during various speed/power conditions and to ensure that a minimum clearance between an engine case and a turbine section of the engine is maintained over the operative envelope of the engine to enhance the useable lifetime of the engine case and the turbine section while at the same time ensuring that the clearance does not exceed a maximum value so as to promote engine performance/efficiency (Paragraph 0040 of Philbrick).
Regarding Claim 13, Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick teaches the invention as claimed and as discussed above. Bacic ‘417 teaches (Figures 1-9) wherein, in comparing the actual clearance (94) with the target clearance (60), one or more processors (78) are further configured to: adjust the engine acceleration rate (Paragraph 0067) when the actual clearance (94) is not within the predetermined margin (70, 72) of the target clearance (60).
As discussed above, although Bacic ‘417 does not teach determining a final target clearance and a transient target clearance, Schelfaut teaches (Figures 1-13) a schedule of clearance targets as a function of core speed (see Figure 4 and Paragraphs 0067-0068) and a schedule of core speed as a function of flight mission time (see Figure 7 and Paragraph 0094-0095).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick to include the plurality of clearance targets associated with the flight mission, as taught by Schelfaut, for the reasons discussed above in claim 1.
Regarding Claim 14, Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick teaches the invention as claimed and as discussed above. Bacic ‘417 further teaches that “the processor 78 may be configured to determine the engine power demand at a fixed iteration rate, for example every 100-1000 ms” (see Paragraph 0056). As discussed above, although Bacic ‘417 does not teach determining a final target clearance and a transient target clearance, Schelfaut teaches (Figures 1-13) a schedule of clearance targets as a function of core speed (see Figure 4 and Paragraphs 0067-0068) and a schedule of core speed as a function of flight mission time (see Figure 7 and Paragraph 0094-0095). Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick does not teach, as discussed so far, wherein the one or more processors are further configured to repeat the steps of: compare between the actual clearance and the transient target clearance; and adjust the engine acceleration rate based on the comparison after the increment of time until the actual clearance is within a predetermined acceptable range of the final target clearance.
Schelfaut teaches (Figures 1-13) wherein one or more processors (212) are configured to repeat the steps of: compare (at 274 in Figure 4 and 286 in Figure 5) between the actual clearance (272) and the transient target clearances (270) and adjust an engine acceleration rate (264) based on the comparison (274, 286) after the increment of time until the actual clearance (272) is within a predetermined acceptable range (342) of a final target clearance (280).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick to have the one or more processors be configured to repeat a comparison between the actual clearance and the transient target clearance and the adjustment of the engine acceleration rate based on the comparison after the increment of time until the actual clearance is within a predetermined acceptable range of the final target clearance, as taught by Schelfaut, in order to allow an acceleration to be completed from any given speed of the engine to a maximum continuous speed (Paragraph 0067 of Schelfaut).
Regarding Claim 15, Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick teaches the invention as claimed and as discussed above. Bacic ‘417 further teaches that “the processor 78 repeatedly determines the engine power demand each time a new measurement is provided by the sensor 76 or one of the sensors 76” or “the processor 78 may be configured to determine the engine power demand at a fixed iteration rate, for example every 100-1000 ms” (see Paragraph 0056). As discussed above, although Bacic ‘417 does not teach determining a final target clearance and transient target clearances, Schelfaut teaches (Figures 1-13) a schedule of clearance targets as a function of core speed (see Figure 4 and Paragraphs 0067-0068) and a schedule of core speed as a function of flight mission time (see Figure 7 and Paragraph 0094-0095). Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick does not teach, as discussed so far, wherein the one or more processors are further configured to repeat the steps of: compare between the actual clearance and the transient target clearances; and adjust of the engine acceleration rate based on the comparison after the increment of time until the gas turbine engine is operating in the second flight condition.
Schelfaut teaches (Figures 1-13) wherein one or more processors (212) are configured to repeat the steps of: a compare (at 274 in Figure 4 and 286 in Figure 5) between the actual clearance (272) and the transient target clearance (270); and adjust an engine acceleration rate (264) based on the comparison (274, 286) after the increment of time until the gas turbine engine (100) is operating in the second flight condition (a condition corresponding to a core speed of a different flight phase; see Figure 7).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick to have the one or more processors be configured to repeat a comparison between the actual clearance and the transient target clearance and the adjustment of the engine acceleration rate based on the comparison after the increment of time until the gas turbine engine is operating in the second flight condition, as taught by Schelfaut, in order to allow an acceleration to be completed from any given speed of the engine to a maximum continuous speed (Paragraph 0067 of Schelfaut).
Regarding Claim 16, Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick teaches the invention as claimed and as discussed above. As discussed above, although Bacic ‘417 does not teach determining a final target clearance and a transient target clearance, Schelfaut teaches (Figures 1-13) a schedule of clearance targets as a function of core speed (see Figure 4 and Paragraphs 0067-0068) and a schedule of core speed as a function of flight mission time (see Figure 7 and Paragraph 0094-0095). Bacic ‘417 further teaches (Figures 1-9) wherein the gas turbine engine (10) includes a clearance adjustment system (at 104, opening or closing a valve to supply or cut off cooling air to portions of the rotor stage casing 42 or segment assembly 56; see Paragraph 0064) configured to adjust the actual clearance between the first component (42) and the second component (38), and wherein the one or more processors (78) are further configured to: cause the clearance adjustment system (at 104) to adjust the clearance based the comparison (at 100) between the actual clearance (94) and the target clearances (60).
Regarding Claim 17, Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick teaches the invention as claimed and as discussed above. As discussed above, although Bacic ‘417 does not teach determining a final target clearance and a transient target clearance, Schelfaut teaches (Figures 1-13) a schedule of clearance targets as a function of core speed (see Figure 4 and Paragraphs 0067-0068) and a schedule of core speed as a function of flight mission time (see Figure 7 and Paragraph 0094-0095). Bacic ‘417 further teaches (Figures 1-9) wherein the target clearances (60) are adjusted each time the engine acceleration rate is adjusted (at 92).
Claims 3-4, 10, 18, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Bacic et al. (US 2015/0247417) in view of Schelfaut (US 2018/0258785), Lewis (US 2014/0321985), and Philbrick et al. (US 2017/0292399) as applied to claims 1 and 12 above, and further in view of Bacic et al. (US 2015/0159499).
Regarding Claim 3, Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick teaches the invention as claimed and as discussed above. Bacic ‘417 further teaches that the rotor tip clearance arrangement is controlled to increase or decrease the rotor tip clearance based on the difference between the calculated clearance and a predefined target clearance (see abstract). Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick does not teach, as discussed so far, wherein in comparing the actual clearance with the transient target clearances, the one or more processors are further configured to: determine that the actual clearance exceeds a predetermined margin of the transient target clearance; and increase the engine acceleration rate until the actual clearance is within the predetermined margin of the transient target clearance.
As discussed above, Schelfaut teaches (Figures 1-13) a schedule of clearance targets as a function of core speed (see Figure 4 and Paragraphs 0067-0068) and a schedule of core speed as a function of flight mission time (see Figure 7 and Paragraph 0094-0095).
Bacic ‘499 teaches (Figures 1-15) that a clearance (44) reduces during engine acceleration phases of the flight and the clearance increases during engine deceleration phases of the flight (Paragraph 0047). Bacic ‘499 further teaches comparing an actual clearance (64) with target clearances (60), wherein one or more processors (abstract) are configured to: determine that the actual clearance (64) exceeds a predetermined margin (70, 72) of the target clearance (60); and increase (via ACU 92) the engine acceleration (based on the acceleration schedule or look up table; see Paragraph 0065) until the actual clearance (64) is within the predetermined margin (70, 72) of the target clearance (60).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick to determine that the actual clearance exceeds a predetermined margin of the target clearance and increase the engine acceleration until the actual clearance is within the predetermined margin of the transient clearance, as taught by Bacic ‘499, in order to control the acceleration of the engine to an acceleration schedule (Paragraph 0065 of Bacic ‘499) so that a minimum clearance can be maintained while preventing tip rub (Paragraph 0004 of Bacic ‘499).
Regarding Claim 4, Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick teaches the invention as claimed and as discussed above. Bacic ‘417 further teaches that the rotor tip clearance arrangement is controlled to increase or decrease the rotor tip clearance based on the difference between the calculated clearance and a predefined target clearance (see abstract). Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick does not teach, as discussed so far, wherein in comparing the actual clearance with the transient target clearances, one or more processors are further configured to: determine that the actual clearance is less than a predetermined margin of the transient target clearance; and decrease the engine acceleration until the actual clearance is within the predetermined margin of the transient target clearance.
As discussed above, Schelfaut teaches (Figures 1-13) a schedule of clearance targets as a function of core speed (see Figure 4 and Paragraphs 0067-0068) and a schedule of core speed as a function of flight mission time (see Figure 7 and Paragraph 0094-0095).
Bacic ‘499 teaches (Figures 1-15) that a clearance (44) reduces during engine acceleration phases of the flight and the clearance increases during engine deceleration phases of the flight (Paragraph 0047). Bacic ‘499 further teaches comparing an actual clearance (64) with a target clearance (60), wherein one or more processors (abstract) are configured to: determine that the actual clearance (64) exceeds a predetermined margin (70, 72) of the target clearance (60); and increase (via ACU 92) the engine acceleration (based on the acceleration schedule or look up table; see Paragraph 0065) until the actual clearance (64) is within the predetermined margin (70, 72) of the target clearance (60).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick to determine that the actual clearance is less than a predetermined margin of the target clearance and increase the engine acceleration until the actual clearance is within the predetermined margin of the transient clearance, as taught by Bacic ‘499, in order to control the acceleration of the engine to an acceleration schedule (Paragraph 0065 of Bacic ‘499) so that a minimum clearance can be maintained while preventing tip rub (Paragraph 0004 of Bacic ‘499).
Regarding Claim 10, Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick teaches the invention as claimed and as discussed above. Bacic ‘417 further teaches that the rotor tip clearance arrangement is controlled to increase or decrease the rotor tip clearance based on the difference between the calculated clearance and a predefined target clearance (see abstract). Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick does not teach, as discussed so far, wherein the one or more processors are further configured to: determine whether engine operating conditions allow for modification of the nominal acceleration rate.
Bacic ‘499 teaches (Figures 1-15) wherein one or more processors (abstract) are configured to determine whether engine operating conditions allow for modification of the nominal acceleration rate (Paragraph 0063-0065 and Figures 10-11).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick to have the one or more processors be configured to determine whether engine operating conditions allow for modification of the nominal acceleration rate, as taught by Bacic ‘499, in order to apply a thrust rate limit to the thrust demand signal being received by the engine controller to protect the engine from tip rub (Paragraphs 0063-0065 of Bacic ‘499).
Regarding Claim 18, Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick teaches the invention as claimed and as discussed above. Bacic ‘417 further teaches that the rotor tip clearance arrangement is controlled to increase or decrease the rotor tip clearance based on the difference between the calculated clearance and a predefined target clearance (see abstract). Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick does not teach, as discussed so far, wherein the one or more processors are further configured to: determine whether engine operating conditions allow for modification of the nominal acceleration rate.
Bacic ‘499 teaches (Figures 1-15) wherein one or more processors (abstract) are configured to determine whether engine operating conditions allow for modification of the nominal acceleration rate (Paragraph 0063-0065 and Figures 10-11).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick to have the one or more processors be configured to determine whether engine operating conditions allow for modification of the nominal acceleration rate, as taught by Bacic ‘499, in order to apply a thrust rate limit to the thrust demand signal being received by the engine controller to protect the engine from tip rub (Paragraphs 0063-0065 of Bacic ‘499).
Regarding Independent Claim 20, Bacic ‘417 teaches (Figures 1-9) a method of operating a gas turbine engine (10), the gas turbine engine including a first component (42) and a second component (38) rotatable (Paragraphs 0042-0043) relative to the first component (42), a clearance (44; see Figure 3) being defined between the first component (42) and the second component (38), the method comprising:
operating the gas turbine engine (10) in a first flight condition (a cruise phase of the flight; see Paragraph 0050 and Figures 4-5);
receiving a demand for a second flight condition (a step-climb phase of the flight; see Paragraph 0051 and Figures 4-5) that is different than the first flight condition (a cruise phase of the flight; see Paragraph 0050 and Figures 4-5);
determining a target clearance (60) between the first component (42) and the second component (38), the target clearance (60) associated with the second flight condition (a step-climb phase of the flight; see Paragraph 0051 and Figures 4-5);
adjusting an engine acceleration rate to a nominal acceleration rate (Paragraph 0067);
comparing (at 100; see Paragraph 0064) an actual clearance (94) with the target clearance (60) after one or more pre-determined increments of time (a fixed iteration rate, for example every 100-1000ms; see Paragraph 0056); and
adjusting the engine acceleration rate based on the comparison (at 100) between the actual clearance (94) and the target clearance (94), wherein the target clearance (94) is adjusted at least partially based on the adjustment to the engine acceleration rate (Paragraph 0067), wherein adjusting the target clearance (94) at least partially based on the adjustment to the engine acceleration rate (Paragraph 0067) involves increasing or decreasing the engine acceleration rate (to maintain the actual control clearance within a control band; see Paragraphs 0052, 0067 of Bacic).
Bacic ‘417 does not teach determining an initial target clearance, a final target clearance, an intermediate target clearance, and a plurality of transient target clearances, initiating a transition between the first flight condition and the second flight condition, wherein adjusting the target clearance at least partially based on the adjustment to the engine acceleration rate involves increasing the engine acceleration rate, wherein adjusting at least one of the plurality of transient target clearances comprises recalculating at least one transient target clearance of the plurality of transient target clearances at each of the one or more pre-determined increments of time during the transition, and wherein the one or more pre-determined increments of time correspond to a rate of recalculation of the gas turbine engine, such that the at least one transient target clearance is iteratively updated throughout the transition or determining whether an actual clearance is consistent with each of the plurality of transient target clearances during the transition by determining whether the actual clearance is within a predetermined margin of a respective transient target clearance of the plurality of transient target clearances at an instance in time, and adjust or maintain the clearance control based on determining whether the actual clearance is consistent with the plurality of transient target clearances during the transition to achieve at least one of the intermediate target clearance or the final target clearance.
Schelfaut teaches (Figures 1-13) a schedule of clearance targets as a function of core speed (see Figure 4 and Paragraphs 0067-0068), the schedule of clearance targets includes an initial target clearance (a target clearance along model 270 as a function of the core speed corresponding to the end of a first flight condition, e.g. a cruise phase of flight; see Figures 4 and 7), a final target clearance (a target clearance along model 270 as a function of the core speed corresponding to the beginning of the second flight condition, e.g., a step-climb phase of flight; see Figures 4 and 7), an intermediate target clearance (a target clearance along model 270 as a function of the core speed between the initial target clearance and the final target clearance; see Figures 4 and 7), and a plurality of transient target clearances (target clearances along model 270 as a function of the core speed during a transition period 370, 372; see Figures 4, 7, 11, and Paragraph 0110), initiating a transition (370, 372) between the first flight condition (a cruise phase of flight; see Figures 7, 11, and 0110) and the second flight condition (a step-climb phase of flight; see Figures 7, 11, and Paragraph 0110), a schedule of core speed as a function of flight mission time (see Figure 7 and Paragraph 0094-0095), comparing (at 286), during the transition, the actual clearance with the plurality of transient target clearances (the machine-learned model 290 outputs adjusted clearance control targets for the entire time in which the aircraft is expected to be in the air; see Paragraph 0083), wherein adjusting at least one of the plurality of transient target clearances is continuous (the blade tip clearance target model includes a machine-learned model trained to adjust the model blade tip clearance targets based at least in part on how an engine has been uniquely operated for a particular flight mission by obtaining present flight data, present flight conditions, and present operating parameters during a flight, which may be continuously updated over the course of a flight; see Paragraphs 0082-0083).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Bacic ‘417 to include the determination of an initial target clearance, a final target clearance, an intermediate target clearance, and a plurality of transient target clearances, initiating a transition between the first flight condition and the second flight condition, wherein adjusting at least one of the plurality of transient target clearances is continuous, as taught by Schelfaut, in order to allow an acceleration to be completed from any given speed of the engine to a maximum continuous speed and to adjust the tip clearance targets based on present flight data (Paragraphs 0067 and 0082 of Schelfaut). Bacic ‘417 in view of Schelfaut does not teach, as discussed so far, wherein adjusting at least one of the plurality of transient target clearances comprises recalculating at least one transient target clearance of the plurality of transient target clearances at each of the one or more pre-determined increments of time during the transition, and wherein the one or more pre-determined increments of time correspond to a rate of recalculation of the gas turbine engine, such that the at least one transient target clearance is iteratively updated throughout the transition or determining whether an actual clearance is consistent with a target clearance by determining whether the actual clearance is within a predetermined margin of the target clearance at an instance in time, and adjust or maintain the clearance control based on determining whether the actual clearance is consistent with the target clearance to achieve the target clearance.
Lewis teaches (Figures 1-11) adjusting at least one of a plurality of transient target clearances (due to transient thermal growth of each component; see Paragraphs 0086-0088) comprises recalculating (in step 94) at least one transient target clearance (44) of the plurality of transient target clearances (44) at each of the one or more pre-determined increments of time (tn; time steps) during the transition (Paragraph 0097), and wherein the one or more pre-determined increments of time (tn) correspond to a rate of recalculation of the gas turbine engine (time steps are similar to the measurement frequency of control parameters and within the processing capacity of the controller and the measurement and calculation periods are matched to the frequency at which the clearance arrangement can act to change the clearance; see Paragraph 0092), such that the at least one transient target clearance (44) is iteratively updated throughout the transition (see Figure 11 and Paragraph 0092).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Bacic ‘417 in view of Schelfaut to adjust at least one of the plurality of transient target clearances by recalculating, by the computing system, at least one transient target clearance of the plurality of transient target clearances at each of the one or more pre-determined increments of time during the transition, and wherein the one or more pre-determined increments of time correspond to a rate of recalculation of the computing system, such that the at least one transient target clearance is iteratively updated throughout the transition, as taught by Lewis, in order to have the time steps at the low end of a range of 0.1 to 10 seconds so that the measurement frequency of control parameters is within the processing capacity of the suitable controllers and to match the measurement and calculation periods to the frequency at which the clearance arrangement can act to change the clearance (Paragraph 0092 of Lewis). Bacic ‘417 in view of Schelfaut and Lewis does not teach, as discussed so far, determining whether an actual clearance is consistent with a target clearance by determining whether the actual clearance is within a predetermined margin of the target clearance at an instance in time, and adjust or maintain the clearance control based on determining whether the actual clearance is consistent with the target clearance to achieve the target clearance.
Philbrick teaches (Figures 1-5) determining whether an actual clearance is consistent with a target clearance by determining whether the actual clearance is within a predetermined margin of the transient target clearance at an instance in time (at 530, where the actual clearance is determined using real-time data from 518; see Figure 5 and Paragraph 0036-0038), and adjust or maintain the clearance control (to 536 or to 518; see Figure 5 and Paragraph 0038) based on determining whether the actual clearance is consistent with the transient target clearance to achieve the target clearance (at 530; see Figure 5).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Bacic ‘417 in view of Schelfaut and Lewis to determine whether an actual clearance is consistent with a target clearance by determining whether the actual clearance is within a predetermined margin of the target clearance at an instance in time, and adjust or maintain the clearance control based on determining whether the actual clearance is consistent with the target clearance to achieve the target clearance, as taught by Philbrick, in order to provide enhanced protection of structures of an aircraft engine during various speed/power conditions and to ensure that a minimum clearance between an engine case and a turbine section of the engine is maintained over the operative envelope of the engine to enhance the useable lifetime of the engine case and the turbine section while at the same time ensuring that the clearance does not exceed a maximum value so as to promote engine performance/efficiency (Paragraph 0040 of Philbrick). Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick does not teach, as discussed so far, wherein adjusting the target clearance at least partially based on the adjustment to the engine acceleration rate involves increasing the engine acceleration rate.
Bacic ‘499 teaches (Figures 1-15) that a clearance (44) reduces during engine acceleration phases of the flight and the clearance increases during engine deceleration phases of the flight (Paragraph 0047). Bacic ‘499 further teaches comparing an actual clearance (64) with a target clearance (60), wherein one or more processors (abstract) are configured to: determine that the actual clearance (64) exceeds a predetermined margin (70, 72) of the target clearance (60); and increase (via ACU 92) the engine acceleration (based on the acceleration schedule or look up table; see Paragraph 0065) until the actual clearance (64) is within the predetermined margin (70, 72) of the target clearance (60).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Bacic ‘417 in view of Schelfaut, Lewis, and Philbrick to determine that the actual clearance exceeds a predetermined margin of the target clearance and increase the engine acceleration until the actual clearance is within the predetermined margin of the transient clearance, as taught by Bacic ‘499, in order to control the acceleration of the engine to an acceleration schedule (Paragraph 0065 of Bacic ‘499) so that a minimum clearance can be maintained while preventing tip rub (Paragraph 0004 of Bacic ‘499).
It is additionally noted that Bacic ‘417 teaches that it is beneficial to minimize the area between the target clearance 60 and minimum clearance 58 since this improves the efficiency of the engine (Paragraph 0052 of Bacic) and teaches a control step 104 that acts to reduce the clearance 44 to improve efficiency when the rotor tip clearance calculated at step 94 is larger than the predefined target clearance and the difference calculated at step 100 is larger than the control band 70, 72 (Paragraph 0065 of Bacic ‘417). Bacic ‘417 that engine acceleration reduces the clearance between the tip and the casing (Paragraphs 0046 and 0051 of Bacic ‘417). Bacic ‘417 further teaches, based on the available tip clearance, a maximum rate of acceleration may be calculated and a rate limiter can be applied to control the rate of acceleration (Paragraph 0067 of Bacic ‘417). It is noted that Bacic’s application of a limit to a maximum rate of acceleration does not mean that the rate of acceleration must decrease or cannot include any increase. One having ordinary skill in the art would have recognized that increasing or decreasing the rate of acceleration allows for the improvement of efficiency by reducing the actual clearance. Therefore, if the difference calculated at step 100 is larger than the control band 70, 72 it would have been common sense to increase or decrease the rate of acceleration, albeit below a maximum rate that would result in tip rub, to maintain the actual clearances within the control band.
Response to Arguments
Applicant’s arguments with respect to claims 1-18 and 20 have been considered but are moot because the arguments do not apply to the new combination of references, necessitated by amendment. However, to the extent possible, Applicant’s arguments have been 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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