JP4107115B2 - Backup fuel flow value setting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides a fuel flow value of fuel supplied to the jet engine in place of a normal fuel flow value setting device when a failure occurs in a fuel control system for controlling the fuel flow of fuel in the jet engine. The present invention relates to a fuel flow value setting device for backup.
[0002]
[Prior art]
The aircraft uses a fuel control system that controls the fuel flow rate of the jet engine. The fuel control system includes two fuel flow value setting devices that set the fuel flow value of the fuel supplied to the jet engine. I have.
[0003]
That is, one of the two fuel flow value setting devices is a normal fuel flow value setting device, and this fuel flow control system controls the optimum fuel flow according to the flight state and the like. The fuel flow value setting device includes: a measured rotational speed of the jet engine (a measured rotational speed of a turbine in the jet engine); a measured pressure value / measured temperature value measured on an inlet side of a compression chamber in the jet engine; Measured pressure value / measured temperature value measured at the outlet side of the engine, measured pressure value / measured temperature value measured at a predetermined position between the combustor and the compressor in the jet engine, and measured at the inlet side of the turbine. The measured pressure value / measured temperature value, the measured pressure value / measured temperature value, etc. measured at the outlet side of the turbine are used as parameters for setting the fuel flow value. .
[0004]
The other one of the two fuel flow value setting devices is a backup fuel flow value setting device, and this backup fuel flow value setting device can be used when a failure occurs in the fuel control system. Instead of the normal fuel flow value setting device, the fuel flow value of the fuel supplied to the jet engine is set. In order to appropriately control the fuel flow by the fuel control system, the backup fuel flow value setting device sets ten or more measured values including the measured rotation speed of the jet engine to set the fuel flow value. It is a parameter.
[0005]
In addition, there exists a thing shown to patent document 1 as a prior art relevant to this invention.
[0006]
[Patent Document 1]
Japanese Examined Patent Publication No. 56-36291 [0007]
[Problems to be solved by the invention]
By the way, although the backup fuel flow value setting device has a smaller number of measurement values than the normal fuel flow value setting device, the fuel flow value is set to a dozen or so measurement values including the rotation speed of the jet engine. Therefore, if the degree of failure of the fuel control system progresses, it becomes impossible to obtain all ten measured values and it becomes difficult to set an appropriate fuel flow value. Therefore, when the aircraft is in a low-speed flight state, the fuel flow rate is low and sufficient thrust cannot be obtained, or when the airplane is in a high-speed flight state, the fuel flow rate is too high and the jet engine is over-rotated. Or, an excessively high temperature at the outlet side of the turbine may be caused. In particular, if the measured rotational speed of the jet engine cannot be obtained, it is not possible to control the fuel flow rate taking into account fluctuations in the rotational speed of the jet engine, thereby preventing over-rotation of the jet engine. Becomes extremely difficult.
[0008]
[Means for Solving the Problems]
In the invention according to claim 1, when a failure occurs in the fuel control system for controlling the fuel flow rate of the fuel of the jet engine, instead of the normal fuel flow rate value setting device, the jet engine In the backup fuel flow value setting device for setting the fuel flow value of the supplied fuel,
A schedule value calculator for calculating a fuel-air schedule value according to the angle value of the throttle;
A pressure correction unit that corrects the measured pressure value on the compressor outlet side measured on the outlet side of the compressor in the jet engine to a correction pressure value that does not exceed a predetermined upper limit pressure value;
A temperature correction unit that corrects the measured temperature value on the compressor inlet side measured on the inlet side of the compressor to a correction temperature value that does not exceed a predetermined upper limit temperature value;
A temperature correction coefficient calculation unit that calculates a temperature correction coefficient based on the correction temperature value output from the temperature correction unit;
The fuel flow rate obtained by multiplying the fuel / air schedule value output from the schedule value calculation unit, the correction pressure value output from the pressure correction unit, and the temperature correction coefficient output from the temperature correction coefficient calculation unit. A multiplier for setting the value;
It is characterized by comprising.
[0009]
Here, the predetermined upper limit pressure value is set in advance so that the engine performance of the jet engine can be improved while preventing the over-rotation of the jet engine and the excessively high temperature on the outlet side of the turbine in the jet engine. This is the upper limit pressure value. Similarly, the predetermined upper limit temperature value is an upper limit set in advance so that the engine performance of the jet engine can be improved while preventing over-rotation of the jet engine and an excessively high temperature on the outlet side of the turbine. This means the temperature value.
[0010]
According to the invention specific matter of the first aspect, the schedule value calculation unit calculates the fuel-air schedule value according to the throttle angle value and outputs it to the multiplier. On the other hand, the pressure correction unit corrects the measured pressure value on the compressor outlet side to the correction pressure value that does not exceed the predetermined upper limit pressure value, and outputs the correction pressure value to the multiplier. The measured temperature value at the compressor inlet side is corrected to the corrected temperature value so as not to exceed the predetermined upper limit temperature value, and is output to the temperature correction coefficient calculation unit. The temperature correction coefficient calculation unit converts the measured temperature value to the correction temperature value. Based on this, the temperature correction coefficient is calculated and output to the multiplier. Then, the fuel flow value is set by multiplying the fuel-air schedule value, the correction pressure value, and the temperature correction coefficient by the multiplier. As a result, even if the degree of failure of the fuel control system proceeds and the measured rotational speed of the jet engine (the measured rotational speed of the turbine) and the measured temperature value on the turbine outlet side cannot be obtained, the compression As long as the measured pressure value on the machine outlet side and the measured temperature value on the compressor inlet side can be obtained as measured values, the fuel flow value can be set by the backup fuel flow value setting device.
[0011]
Here, since the turbine and the compressor are interlocked and the measured pressure value on the compressor outlet side tends to correspond to the fluctuation of the rotation speed of the jet engine, the rotation speed of the jet engine is taken into account. While the fuel flow rate can be controlled, the measured temperature value on the compressor outlet side tends to correspond to a change in the atmospheric state, and therefore the fuel flow rate can be controlled in consideration of the atmospheric state. Further, the pressure correcting unit corrects the measured pressure value on the compressor outlet side to the corrected pressure value so as not to exceed the predetermined upper limit pressure value, and the temperature correcting unit corrects the measured temperature on the compressor inlet side. Since the correction temperature value is corrected so that the value does not exceed the predetermined upper limit temperature value, it is suppressed that the fuel flow value becomes excessive.
[0012]
In the invention according to claim 2, in addition to the invention specific matter according to claim 1, the pressure correction unit includes:
The correction pressure value increases as the measured pressure value increases until the measured pressure value reaches an upper limit pressure slightly lower than the predetermined upper limit pressure value, and the measured pressure value decreases the upper limit front pressure. When exceeding, under the pressure correction relationship such that the correction pressure value decreases as the measurement pressure value increases, the measurement pressure value is corrected to the correction pressure value,
The temperature correction unit is
The corrected temperature value increases as the measured temperature value increases until the measured temperature value reaches an upper limit temperature slightly lower than the predetermined upper limit temperature value, and the measured temperature value decreases the upper limit temperature. If it exceeds, the measured temperature value is corrected to the corrected temperature value under a temperature correction relationship in which the corrected temperature value decreases as the measured temperature value increases.
[0013]
According to the invention specific matter described in claim 2, the same effect as the effect of the invention specific matter described in claim 1 is obtained.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[0015]
FIG. 1 is a block diagram of a backup fuel flow value setting device according to an embodiment of the present invention, and FIG. 2 is a diagram showing correction contents of a temperature correction unit according to an embodiment of the present invention. FIG. 3 is a diagram showing correction contents of the pressure correction unit according to the embodiment of the present invention, and FIG. 4 is a schematic cross-sectional view of a general jet engine.
[0016]
First, before explaining the backup fuel flow value setting device 1 according to the embodiment of the present invention shown in FIG. 1, the configuration of a general jet engine 3 according to the embodiment of the present invention shown in FIG. Explained.
[0017]
As shown in FIG. 4, the jet engine 3 is a biaxial engine mounted on an aircraft, and is based on a cylindrical engine body 5 extending in the engine axial direction (front-rear direction, left-right direction in FIG. 4). Yes. A low-pressure compressor 7 is provided at the front part (left part in FIG. 4) in the engine body 5 to compress the air that has been sent into the engine body 5 at a low pressure. A high-pressure compressor 9 is provided on the rear side of the machine 7 to compress the low-pressure compressed air at a high pressure. A combustor 11 for combusting fuel in high-pressure compressed air is provided behind the high-pressure compressor 9 in the engine body 5. The combustor 11 includes a plurality of fuel nozzles 13 for injecting fuel. I have.
[0018]
Further, a high-pressure turbine 15 driven by the expansion of combustion gas from the combustor 11 is provided on the rear side of the combustor 11 in the engine body 5, and high-pressure compression is performed in conjunction with the driving of the high-pressure turbine 15. In the engine body 5, a high-pressure turbine shaft 17 that connects the rotor portion 15 a of the high-pressure turbine 15 and the rotor portion 9 a of the high-pressure compressor 9 and extends in the engine axial direction is rotatably provided in the engine body 5. It has been. A low pressure turbine 19 driven by the expansion of combustion gas that has driven the high pressure turbine 15 is provided on the rear side of the high pressure turbine 15 in the engine body 5. In the engine body 5, the rotor portion 19 a of the low-pressure turbine 19 and the rotor portion 7 a of the low-pressure compressor 7 are connected in the engine body 5 so as to drive the compressor 7 and extend coaxially with the high-pressure turbine shaft 17 in the engine axial direction. A low-pressure turbine shaft 21 is rotatably provided.
[0019]
Next, the backup fuel flow value setting device 1 according to the embodiment of the present invention will be described.
[0020]
As shown in FIG. 1, the backup fuel flow value setting device 1 is used for a normal operation when a failure occurs in a fuel control system (not shown) that controls the fuel flow rate of the jet engine 3 (see FIG. 4). Instead of a fuel flow value setting device (not shown), this is a device that sets the fuel flow value of the fuel supplied to the jet engine 3. The backup fuel flow value setting device 1 includes a schedule value calculation unit 23, a pressure correction unit 25, a temperature correction unit 27, a coefficient calculation unit 29, a first multiplication unit 31, and a second multiplication unit 33. The specific configuration of these components is as follows.
[0021]
That is, the schedule calculation unit 23 calculates the fuel / air schedule value (fuel / air ratio) WF / P′N according to the angle value D of the throttle 35. Here, the fuel / air schedule value WF / P′N is expressed as a function of only the angle value D of the throttle 35.
[0022]
Further, as shown in FIG. 3, the pressure correction unit 25 sets the measured pressure value P on the compressor outlet side measured on the outlet side of the low-pressure compressor 7 (see FIG. 4) in the jet engine 3 to a predetermined upper limit pressure value. The correction pressure value P ′ is corrected so as not to exceed Pc. More specifically, the pressure correction unit 25 increases the correction pressure value P ′ as the measurement pressure value P increases until the measurement pressure value P reaches the upper limit front pressure Ps slightly lower than the predetermined upper limit pressure value Pc. When the measured pressure value P exceeds the upper limit pressure Ps, the measured pressure value P is corrected to the corrected pressure under the pressure correction relationship in which the corrected pressure value P ′ decreases as the measured pressure value P increases. The value is corrected to P ′. Here, the proportional constant of the corrected pressure value P ′ when the corrected pressure value P ′ increases is approximately 1, and the proportional constant of the corrected pressure value P ′ when the corrected pressure value P ′ decreases is − (minus). ). Further, the predetermined upper limit pressure value Pc can improve the engine performance of the jet engine 3 while preventing the overspeed of the jet engine 3 (the turbine shafts 17 and 21) and the excessively high temperature on the outlet side of the low pressure turbine 19. As mentioned above, it means a preset upper limit pressure value. If the pressure is corrected so as not to exceed the predetermined upper limit pressure value Pc, the measured pressure value P may be corrected to the corrected pressure value P ′ under another pressure correction relationship other than the pressure correction relationship. Absent.
[0023]
Further, as shown in FIG. 4, the temperature correction unit 27 does not exceed the predetermined upper limit temperature value Tc with respect to the measured temperature value T on the compressor inlet side measured on the inlet side of the low-pressure compressor 7 in the jet engine 3. Is corrected to a correct correction temperature value T ′. More specifically, the corrected temperature value T ′ increases with the increase in the measured temperature value T until the measured temperature value T reaches the upper limit temperature Ts that is slightly lower than the predetermined upper limit temperature value Tc. When the value T exceeds the upper limit temperature Tc, the measured temperature value T is corrected to the corrected temperature value T ′ under a temperature correction relationship in which the corrected temperature value T ′ decreases as the measured temperature value T increases. Is. Here, the proportionality constant of the correction temperature value T ′ when the correction temperature value T ′ increases is approximately 1, and the proportionality constant of the correction temperature value T ′ when the correction temperature value T ′ decreases is approximately −1. It is. The measured temperature value T is expressed as an absolute temperature, and the predetermined upper limit temperature value Tc is the engine performance of the jet engine 3 while preventing the overspeed of the jet engine 3 and the excessively high temperature on the outlet side of the low-pressure turbine 19. The upper limit temperature value is set in advance so that the temperature can be increased. If the correction is made so as not to exceed the predetermined upper limit temperature value Tc, the measured temperature value T may be corrected to the corrected temperature value T ′ under another temperature correction relationship other than the temperature correction relationship. Absent.
[0024]
Again, as shown in FIG. 1, the temperature correction coefficient calculation unit 29 calculates the temperature correction coefficient N based on the correction temperature value T ′ output from the temperature correction unit 27. Here, the temperature correction coefficient N is calculated by √ (T ′ / 288,15) and indicates a deviation from the standard atmospheric condition.
[0025]
The first multiplier 31 multiplies the fuel / air schedule value WF / P′N output from the schedule value calculation unit 23 and the correction pressure value P ′ output from the pressure correction unit 25 to calculate WF / N. Is. The second multiplier 33 multiplies the WF / N output from the first multiplier 31 and the temperature correction coefficient N output from the temperature correction coefficient calculator 29 to set the fuel flow value WF. is there. The first multiplier 31 multiplies the fuel / air schedule value WF / P′N and the temperature correction coefficient N to calculate WF / P ′, and the second multiplier 33 calculates WF / P ′ and the pressure correction value P ′. May be set to set the fuel flow rate value WF.
[0026]
Next, the operation of the embodiment of the present invention will be described.
[0027]
The schedule value calculation unit 23 calculates the fuel / air schedule value WF / P′N according to the angle value of the throttle 35 and outputs the fuel / air schedule value WF / P′N to the first multiplier 31. The first multiplier 31 calculates the fuel / air schedule value WF / P ′. N is output to the second multiplier 33. On the other hand, the pressure correcting unit 25 corrects the corrected pressure value P ′ to the corrected pressure value P ′ that does not exceed the predetermined upper limit pressure value Pc, and outputs the corrected pressure value P ′ to the first multiplier 31. Then, the first multiplier 31 outputs the corrected pressure value P ′ to the second multiplier 33. Further, the temperature correction unit 27 corrects the measured temperature value T on the compressor inlet side to a correction temperature value T ′ so as not to exceed a predetermined upper limit temperature value Tc, and outputs the correction temperature value T ′ to the temperature correction coefficient calculation unit 29. The calculation unit 29 calculates the temperature correction coefficient N based on the corrected temperature value T ′ and outputs it to the second multiplier 33. Then, the fuel multiplier value WF is set by multiplying the fuel-air schedule value WF / P′N, the correction pressure value P ′, and the temperature correction coefficient N by the second multiplier 33. As described above, even if the degree of failure of the fuel control system progresses and the measured rotational speed of the jet engine 3 and the measured temperature value on the outlet side of the low-pressure turbine 19 cannot be obtained, the measured pressure value on the compressor outlet side can be obtained. As long as P and the measured temperature value T on the compressor inlet side can be obtained as measured values, the fuel flow value WF can be set by the backup fuel flow value setting device 1.
[0028]
Here, the low-pressure turbine 19 and the low-pressure compressor 7 in the jet engine 3 are interlocked, and the measured pressure value P on the compressor outlet side corresponds to fluctuations in the rotational speed of the jet engine 3 (the rotational speed of the low-pressure turbine 19). Therefore, the fuel flow rate can be controlled in consideration of the rotational speed of the jet engine 3, and the measured temperature value T on the compressor outlet side tends to correspond to the change in the atmospheric state. Thus, the fuel flow rate can be controlled. Further, the pressure correction unit 25 corrects the measured pressure value P on the compressor outlet side to the corrected pressure value P ′ so as not to exceed the predetermined upper limit pressure value Pc, and the temperature correction unit 27 measures the measured temperature on the compressor inlet side. Since the value T is corrected to the corrected temperature value T ′ so as not to exceed the predetermined upper limit temperature value Tc, it is possible to suppress the fuel flow value WF from becoming excessive.
[0029]
As described above, according to the embodiment of the present invention, the degree of failure of the fuel control system proceeds, and the measured rotational speed of the jet engine 3 and the measured temperature value on the outlet side of the low-pressure turbine 19 cannot be obtained. However, as long as the measured pressure value P on the compressor outlet side and the measured temperature value T on the compressor inlet side can be obtained as measured values, the fuel flow value for backup is suppressed while suppressing the fuel flow value WF from becoming excessive. Since an appropriate fuel flow value WF can be set by the value setting device 1 according to the flight state of the aircraft, a large amount of fuel is supplied to the jet engine 3 to obtain sufficient thrust when the aircraft is in a low speed state. In addition, when the aircraft is in a high speed state, excessive fuel is not supplied to the jet engine 3 and the jet engine 3 is over-rotated and the low-pressure turbine 19 is discharged. Over hot side can be easily prevented.
[0030]
It should be noted that the present invention is not limited to the description of the above-described embodiment of the invention, and can be implemented in various other modes, for example, by making appropriate changes as follows. That is, instead of the biaxial jet engine 3, a single axial jet engine may be used. In this case, the measured pressure value measured on the outlet side of the compressor in the single axial jet engine, the compressor It is used as a parameter for setting the measured temperature value and fuel flow value measured at the inlet side of the fuel.
[0031]
【The invention's effect】
According to the first or second aspect of the invention, the degree of failure of the fuel control system progresses, and the measured rotational speed of the jet engine and the measured temperature value on the turbine outlet side cannot be obtained. As long as the measured pressure value on the compressor outlet side and the measured temperature value on the compressor inlet side can be obtained as measured values, the fuel flow rate for backup is suppressed while preventing the fuel flow rate from becoming excessive. Since an appropriate fuel flow value can be set according to the flight status of the aircraft by the value setting device, when the aircraft is in a low speed state, a large amount of fuel is supplied to the jet engine and sufficient thrust can be obtained. In addition, when the aircraft is in a high speed state, excessive fuel is not supplied to the jet engine, and the overspeed of the jet engine and the turbine Over hot mouth side can be easily prevented.
[Brief description of the drawings]
FIG. 1 is a block diagram of a backup fuel flow value setting device according to an embodiment of the present invention.
FIG. 2 is a diagram showing correction contents of a temperature correction unit according to the embodiment of the present invention.
FIG. 3 is a diagram showing correction contents of a pressure correction unit according to the embodiment of the present invention.
FIG. 4 is a schematic cross-sectional view of a general jet engine according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Backup fuel flow value setting apparatus 3 Jet engine 7 Low pressure compressor 23 Schedule value calculation part 25 Pressure correction part 27 Temperature correction part 29 Temperature correction coefficient calculation part 31 1st multiplier 33 2nd multiplier 35 Throttle

Claims (2)

Backup for setting the fuel flow value of the fuel supplied to the jet engine in place of the normal fuel flow value setting device when a failure occurs in the fuel control system for controlling the fuel flow rate of the jet engine fuel. In the fuel flow value setting device,
A schedule value calculator for calculating a fuel-air schedule value according to the angle value of the throttle;
A pressure correction unit that corrects the measured pressure value on the compressor outlet side measured on the outlet side of the compressor in the jet engine to a correction pressure value that does not exceed a predetermined upper limit pressure value;
A temperature correction unit that corrects the measured temperature value on the compressor inlet side measured on the inlet side of the compressor to a correction temperature value that does not exceed a predetermined upper limit temperature value;
A temperature correction coefficient calculation unit that calculates a temperature correction coefficient based on the correction temperature value output from the temperature correction unit;
The fuel flow rate obtained by multiplying the fuel / air schedule value output from the schedule value calculation unit, the correction pressure value output from the pressure correction unit, and the temperature correction coefficient output from the temperature correction coefficient calculation unit. A multiplier for setting the value;
A back-up fuel flow rate value setting device comprising: The pressure correction unit is
The correction pressure value increases as the measured pressure value increases until the measured pressure value reaches an upper limit pressure slightly lower than the predetermined upper limit pressure value, and the measured pressure value decreases the upper limit front pressure. When exceeding, under the pressure correction relationship such that the correction pressure value decreases as the measurement pressure value increases, the measurement pressure value is corrected to the correction pressure value,
The temperature correction unit is
The corrected temperature value increases as the measured temperature value increases until the measured temperature value reaches an upper limit temperature slightly lower than the predetermined upper limit temperature value, and the measured temperature value decreases the upper limit temperature. The measured temperature value is corrected to the corrected temperature value under a temperature correction relationship in which the corrected temperature value decreases as the measured temperature value increases when the measured temperature value is exceeded. 2. The backup fuel flow value setting device according to 1.

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