JPS5928025A - Controller of gas turbine engine - Google Patents

Abstract

PURPOSE:To prevent surging reliably from generating, by correcting a target speed according to a degree of detected surging, in a device making closed loop control so as to coincide a speed of a gas generator with the given target speed. CONSTITUTION:The titled controller computes a fuel supply quantity corresponding to a target speed based on the output of an accelerator opening sensor 17 in a control part 11 and controls a fuel supply device 8 to a combustor 7 according to a computed value of the control part 11. Feed back control is done so that an actual speed to be detected by a speed detector 13 of a gas generator coincides with the target speed. In this instance, intensity of surging is decided based on an output of a surge sensor 16 provided on a compressor 1. The target speed of the gas generator is corrected so that the surging is avoided according to a decision of the sensor 16. This correction is made to perform so that a speed after it has been once reduced is increased again gradually.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control system H for a gas turbine engine, and in particular is an improvement aimed at reliably preventing the occurrence of surging in an automobile gas turbine engine without impairing operating performance.

In a gas turbine engine, especially a two-shaft gas turbine engine, if the air flow rate passing through the compressor and the pressure ratio between the inlet and outlet of the compressor simultaneously fall within a certain range, noise and vibration may occur. It is known that surging can occur. When surging occurs, it often causes serious problems such as engine inoperability or damage. On the other hand, it is well known that the efficiency of an engine is highest near where surging occurs, and the most important point in designing the control system of a gas turbine engine is to operate it as close to surging as possible while avoiding surging. This is one of the challenges.

Here, conventionally, Japanese Patent Application Laid-Open No. 53-93212. Tokuko Showa 5
In order to avoid such surging, as disclosed in Japanese Patent Application No. 6-7049, etc., program control is implemented in which predetermined limits are applied to control variables such as fuel supply violet and variable nozzle opening depending on operating conditions. was being carried out. However, such program control requires a larger surging margin than necessary in order to avoid surging in any driving mode, resulting in poor acceleration performance and efficiency. There were negative effects. Additionally, there was a risk that the surging margin determined at the time of design would be insufficient due to changes in the engine over time, crystallization in the fuel flow path, etc., and surging would occur.

In addition, when closed-loop control is performed on the rotational speed of the gas generator, when surging occurs, the rotational speed of the gas generator decreases, so in order to correct this, control is performed so that more fuel is supplied. However, there was also a control problem in that it actually encouraged surging even further.

The purpose of the present invention is to focus on such conventional problems,
The system detects surging in the gas turbine engine and corrects and controls the target rotational speed of the gas generator in a direction that avoids surging according to the degree of surging, thereby ensuring surging in any operating mode. An object of the present invention is to provide a control device for a gas turbine engine that can avoid such problems.

The present invention will be described in detail below based on the drawings.

FIG. 1 shows an example of the overall configuration of a gas turbine engine to which the present invention is applied.

The gas turbine engine in this example is a two-shaft gas turbine engine with a heat exchanger, which is a type of regenerative one-gas turbine.

In the figure, 1 is a compressor, and 2 is a compressor turbine installed coaxially with the compressor 1 on the gas generator shaft IA. A power turbine 3 drives a transmission (not shown) via a reduction gear 4 and transmits power to the wheels. Reference numeral 5 designates an air filter, in which atmospheric air is taken in and purified, compressed by a compressor l, passed through a heat exchanger 6, heated, and distributed to a combustor 7. In the combustor 7, a fuel supply device 8
The fuel supplied from the heat exchanger 6 is combusted by the air supplied through the heat exchanger 6 as described above. The combustion gas drives the compressor turbine 2 and further drives the power turbine 3 via the variable nozzle 9, and then is cooled via the heat exchanger 6 and discharged into the atmosphere as exhaust gas from the exhaust muffler 10.

The control system that drives and controls each part configured in this way has the control section 11 as its core, and includes a drive device 12 that drives the fuel supply device 8 and the variable nozzle 9, and includes gas generator rotation speed detection. Vessel 13. Power turbine rotation speed detector 14. Compressor turbine artificial temperature detector 15. A surge sensor 16 and an accelerator opening sensor 17 that detects the depression angle of the accelerator pedal are input to the control unit 11. Here, the surge sensor 16 has a function of detecting the pressure on the population side or the outlet side of the air to the compressor 1, or the differential pressure between the two, and detects when surging occurs or when the state is close to surging. The occurrence of surging is detected by utilizing the fact that there is a large fluctuation in the pressure difference between the air intake side and the outlet side of the container 1.

FIG. 2 shows an example of the mounting position of the surge sensor 16 having such a configuration. In the figure, 20+ is the suction casing 2
02 and the shroud 203. 204 is a shaft, 205 is a compressor impeller (rotor) attached to the shaft 204, 206
is a vane type diffuser, this diffuser 208
A vaneless diffuser (air passage) 2o7 is formed between and the a-tube 205. A small hole 208 is provided in the shroud 203 near the entrance of the rotor 205, and the surge sensor 18 is attached to the opening side of the small hole 208 that faces the rotor 205. In this case, the surge sensor 18 detects the pressure (static pressure) near the inlet of the rotor 205. Also,
Another mounting position for the surge sensor 18 is the rotor 20.
The opening side facing the rotor 205 in a small hole 208 provided in the shroud 203 near the exit of the rotor 205 may also be used. In this case, the surge sensor 1θ detects the pressure (static pressure) in the air passage 207 near the outlet of the rotor 205. The pressure sensor used as the surge sensor 16 has a quick response of, for example, 1 to 10 m5, and is resistant to pressure shock when surging occurs. Next, as for the basic control of the above-mentioned control system, the target rotational speed is determined mainly by the depression angle of the accelerator pedal, which is the required value of the rotational speed, the fuel supply amount corresponding to that target value is calculated, and the fuel injection The gas generator is rotated by driving the fuel supply system including the valve, and feed pump control (closed loop control) is performed so that the rotation speed matches the target rotation speed mentioned above.
Feedback control of the turbine inlet temperature is performed by opening and closing the variable nozzle 8 with respect to a predetermined target value of the turbine inlet temperature to achieve the highest efficiency according to the rotation speed of the gas generator. In addition to temperature control, there are three types of surging control that detect surging of the gas turbine engine and feedback control the fuel supply amount and the opening degree of variable nozzle 9 according to the detected degree of surging.

The device of the present invention is comprised of a control system that incorporates a surging control function in addition to the above-mentioned rotation control, the details of which are shown in FIG. 3(A).

In the figure, 31 is a low-pass filter section, 32 is a gas generator rotation speed (Ngg) target value generation section, 33 is a calculation section, 34 is a fuel supply system drive section, 35 is a surge avoidance signal generation section, 38
is a frequency-voltage converter (hereinafter referred to as FV converter),
37 and 38 are subtracters. The FV converter 36 converts the detection signal 13S from the gas generator rotation speed detector 13 into a voltage signal proportional to the rotation speed, and sends it to the subtraction unit 38 and the surge avoidance signal generation unit 35 as a gas generator rotation speed signal 389. Send. The surge avoidance signal generator 35 receives the surging signal 1flS from the surge sensor 1θ and the gas generator rotational speed signal 38S from the FV converter, and
A surge avoidance signal 122S for avoiding surging is sent to the subtraction unit 37 according to the degree of surging, and it is also diagnosed whether the surge census B is normal, and if it is not normal, it lowers the surge sensor abnormality diagnosis signal 135S. It is sent to the area filter section 31. The low-pass filter section 31 receives the accelerator opening signal 1? from the accelerator opening sensor 17? The accelerator opening signal 175 is input at a predetermined time in order to limit the acceleration of the gas generator based on the accelerator opening signal +79. Low-pass filtering is performed using a first-order delay circuit with a constant. Furthermore, when the surge sensor 16 is diagnosed as abnormal based on the surge sensor abnormality diagnosis signal 135S, the acceleration of the gas generator performed based on the accelerator opening signal 17S is further increased by increasing the value of the above-mentioned time constant. limit and regularly suppress the occurrence of surging.

FIG. 3 (,B) shows an example of the circuit configuration of the low-pass filter section 31, where BA is a buffer amplifier, R1 and R2 are resistors,
C is a capacitor, and ASW is an analog switch. In a normal state, there is no input of the signal 135S, so the switch ASiW is in a closed state, and the time constant τ becomes τ=R1·C. However, when surging occurs, signal 135
The switch ASW opens when S enters, and the time constant increases to τ = (R1+R2) Φ C .

Next, the target value generating section 32 inputs the low-pass filtered accelerator opening signal 31S from the low-pass filtering section 31, and generates a target rotation speed proportional to this signal and a target rotation speed at idle as a function. These are added and sent to the subtraction unit 37 as the target rotational speed signal 32S of the gas generator. The subtraction unit 37 subtracts the surge avoidance signal 122S from the output signal 32S of the target value generation unit 32, and the subtraction result is sent to the subtraction unit 3.
Send to 8. The subtraction unit 38 subtracts the gas generator rotation speed signal 38S from the output signal of the subtraction unit 37, and sends the subtraction result to the calculation unit 33 as a rotation deviation signal 38S. The calculation unit 33 is proportional.

It has a PID controller consisting of three elements, integral and differential, and a limiter that controls the variation range, and the supplied rotational deviation signal 3
A PID control signal is generated such that 8S gradually becomes zero. Furthermore, in order to prevent blowout and overtemperature in the combustor 7, the change range of the PID control signal is limited by a limiter 7 having predetermined functional characteristics, and the fuel control signal 33S is sent to the fuel supply system drive unit. Send to 34. The fuel supply system drive unit 34 is composed of a pulse width modulator, converts the fuel control signal 33S into a pulse signal suitable for driving an electromagnetic fuel injection valve, and outputs the fuel supply system 8 as a fuel supply system drive signal 34S. This controls the fuel supply.

FIG. 4(A) shows one configuration of the surge avoidance signal generating section 35.
An example is shown in which 110 is a surge determination section, 120 is a function generation section, and 130 is a sensor abnormality diagnosis section. The surge determination section 110 includes either the surge sensor 16 or the surge determination section 110, where 111 is a filter that attenuates unnecessary frequency bands of the output signal 16S from the surge sensor 16. 112 is the background noise level (B
GL) generator, which normally rectifies and averages the output signal of the filter I11 and outputs it as a background noise level voltage (hereinafter referred to as BGL voltage) 1129.

In addition, the signal 111 from the filter 111 is supplied for a predetermined period of time after it is determined that surging is occurring based on the energization prohibition signal from the monostable multi-by-break 11B (described later) + 1BS.
By shorting S, 1129 is output. Fourth
Figure (B) shows a signal 111 in this BGL generator 112.
An example of a circuit configuration for rectifying and averaging S is shown. When the analog switch SW is closed due to the energization prohibition signal 1185'j from the multivibrator tte, the signal 111S from the filter 111 is half-circuited from this switch SW. Wave rectifier HWR.

B via low-pass filter LPF and amplifier AMP
A GL signal 112S is formed.

Next, 113 is a comparator, which compares the output signal 111S from the filter 111 with the BGL voltage 112s, and when the filter s'w is closed by the energization prohibition signal 11EIs from the multi-by-break 1lf (from the filter 111), the output signal 111S from the filter 111 is The signal 111S is sent from this switch Sw to the half-wave rectifier H.
W.R.

B via low-pass filter LPF and amplifier AMP
A GL signal 112S is formed.

Next, 113 is a comparator, which compares the output signal 111S from the filter 111 with the BGL voltage 112S, and when the output signal 1lls from the filter Ill exceeds the BGL voltage 112S, the surging shown in FIG. 5(B) occurs. A detection signal 113S is output. Here, the output signal 111S from the filter 111 changes depending on the degree of surging, and as shown in FIG.
Waveform 111S-1,llll5-2 depending on the degree of weak/medium
and lll5-3. As a result, the pulse width and number of the surging detection signal 113S change depending on the degree of surging, and for example, this signal + 1
If the pulse width of 35 is wide and the number of pulses is large, it means that strong surging is occurring. 114 is an integrator that charges the surging detection signal +135 relatively quickly and discharges it slowly. A comparator 115 compares the integral signal +149 (see FIG. 5(C)) from the integrator 114 with a predetermined voltage VIIs, and outputs the integral signal 114.
When S exceeds the predetermined voltage VIIS, Fig. 5(D)
It has a hysteresis function that outputs a surging determination signal 115s as shown in FIG. The integral signal 114S corresponds to the degree of surging with a voltage value, and in the comparator 115, voltages caused by weak surging or noise that is not surging are compared with a predetermined voltage VIIs and rejected. As a result, surging of a predetermined intensity or higher is determined to be substantial surging, and surging determination can be made extremely accurately and with high sensitivity.

1113 is a monostable multi-by-break, which generates a pulse signal 1163 (see FIG. 5 (E)) having a predetermined pulse width from the rising edge of the surging determination signal 115S, and B for a predetermined time from the moment when surging is determined.
In order to prevent excessive rise in the GL voltage, this signal 118S is outputted to the background noise level generating section 112 as a energization prohibition signal.

Next, in the function generating section 120, 121 is a monostable multivibrator, which generates a surging pulse signal 121S (see FIG. 5(F)) having a predetermined pulse width from the rising edge of the surging determination signal 1155. Further, 122 is an integrator, and the surging pulse signal 121
S is charged relatively quickly and discharged slowly, and is output as a surge avoidance signal 122S (see FIG. 5(G)).

Next, in the sensor abnormality diagnosis section 130, 131 is a filter, which is similar to the filter of the surge determination section 110.
Unnecessary frequency bands are attenuated from the output signal IBS from the surge sensor 16. 132 is an averaging circuit that rectifies and averages the output signal 1313 from the filter 131. A comparator 133 compares the average signal 132S from the averaging circuit 132 with a predetermined reference voltage V133, and generates a positive output signal 133S when the average signal 132S passes r times around the reference voltage V133. Further, 134 is a comparator, which outputs a positive output signal 13 when the voltage of the gas generator rotational speed signal mentioned above is −F times around the predetermined reference voltage v134.
Generate 4S. 135 is an AND gate, which takes the AND of the output signals 133S and 134S of the comparator 133 and the comparator 134, and outputs these output signals 133S,
When +34S are both positive, a positive sensor abnormality diagnosis signal 135S is generated.

Here, under conditions where no surging occurs, a voltage value corresponding to a relatively small rotational speed of the gas generator at which surging IB can generate a sufficiently large output signal is given as the value of the reference voltage V, and -force, The value of the reference voltage V133 is preset as a voltage value corresponding to a relatively small average signal obtained when the gas generator rotation speed is equal to or higher than the value of the reference voltage VL31+. Set it. As a result, if the output signal does not become sufficiently large even though the surge sensor I8 has failed and surging has occurred, the sensor abnormality diagnosis signal +359 from the sensor actual diagnosis section 130 will detect the failure. can be detected. Moreover, it is effective not only for failures of the surge sensor 16 but also for defective wiring and poor contact of connectors. Furthermore, sensor abnormality diagnosis signal! Based on 35S, an abnormality in the surge sensor 18 can be displayed by a light emitting diode (not shown) or the like, and the abnormality in the surge sensor 18 can be communicated to the driver.

Next, FIG. 6 is a time chart showing the operation in this embodiment shown in FIG. The operation of this embodiment will be explained below based on FIG.

Now, at time TI, as shown in FIG. 6(A), if the driver presses the accelerator pedal relatively rapidly from a slightly depressed state to fully open the accelerator, the low-pass filter 31 The target rotational speed Ngg' of the gas generator obtained by the target value generator 32 via
It also increases as shown in B). Target rotation speed Ngg
When ' increases, the rotational deviation signal 38S obtained sequentially through the subtraction section 37 and the subtraction section 38 also increases, so the calculation section 33 issues a command to increase the amount of fuel, as shown in FIG. 6(E). Thus, the fuel supply amount wf increases. Fuel supply amount wf
When increases, the rotational speed Ngg of the gas generator increases as shown in Fig. 6 (
As shown in C), the power turbine 3
The rotational speed Npt 4 gradually decreases to -1-y as shown in FIG. 6 (11).

Here, it is known that surging tends to occur during acceleration of such a gas generator, and this tendency increases as the acceleration becomes steeper. Therefore, if it is assumed that a slight surging occurs at time T2 during acceleration of the gas generator, the output signal 16S of the surge sensor 16 corresponds to the increased surging width 1flS- as shown in FIG. 6(F). 1 is generated, and the surge avoidance signal 122S as shown in FIG. 6(G) is generated from the surge avoidance signal generator 35. In response to the surge avoidance signal 122S, the target rotational speed Ngg' of the gas generator is immediately subtracted by a predetermined amount in the subtraction unit 37, and then gradually returned to the original value (see FIG. 6(B)).

Therefore, the amount of fuel supplied is also temporarily reduced, so the surging disappears quickly and the engine can continue to operate. In addition, since the surging detection sensitivity of the surge avoidance signal generating section 35 is sufficiently high as described above, it is possible to detect not only strong surging but also eaves-level surging or a precursor to surging, so that there is always no surging or very weak surging. The surging state can be controlled to ensure efficient operation without sacrificing the driving feel.

Although FIG. 6 shows how to avoid surging during the acceleration process of the gas generator, it goes without saying that surging that occurs in a steady state can also be controlled in exactly the same way.

Further, in this embodiment, the surge avoidance signal generation section 35
Since the failure diagnosis of the surge sensor 16 is performed at the time of the surge sensor 16, even if the surge sensor 16 fails during acceleration of the gas generator, where the risk of surging is highest, the time constant can be increased in the low-pass filter section 31. By doing so, the occurrence of surging can be suppressed and there is no risk of damaging the engine.

As explained above, according to the present invention, surging of the gas turbine engine is detected, and when surging occurs, the target rotational speed of the gas generator is reduced relatively quickly, and then the original state is gradually restored. Since I configured it to return to
It is possible to operate the engine in a state as close to the surging region as possible while avoiding surging, thereby enabling efficient operation with excellent acceleration without damaging the engine or impairing drivability.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a gas turbine engine to which the present invention is applied, Fig. 2 is a partial sectional view showing the mounting position of the surge sensor shown in Fig. 1, and Fig. 3 (A) is a control system of the engine shown in Fig. 1. 3(B) is a circuit diagram showing an example of the low frequency feeding section shown in FIG. 3(A), and FIG.
FIG. 4(A) is a detailed block diagram of the surge avoidance signal generator shown in FIG. 4(A), FIG. 4(B) is a detailed block diagram of a part of the BGL generator shown in FIG. - (G) is a signal waveform diagram of each part shown in Fig. 3 (A), Fig. 6 (A) -
(G) is a timer 1 showing the operation of each part of the engine shown in the first figure. 1... Compressor. IA...Gas generator shaft, 2...Compressor turbine, 3...Power turbine, 4...Reducer, 5...-Air fill, 6...Heat exchanger, ? ...Combustor, 8.Fuel supply device, 9.Variable nozzle, 10.Exhaust muffler, 11.Control unit, 12.Drive device, 13.Gas generator rotation. Speed detector, 14.../,
Quad turbine rotation speed detector, 15... Compressor turbine inlet temperature detector, 18... Surge sensor, 17... Accelerator opening sensor, 31... Low pass filter section, 32... Target value generation Department. 33... Arithmetic unit, 34... Fuel supply system drive unit, 35... Surge avoidance signal generation unit, 36... FV converter, 37.38... Subtraction unit, 110... Surge determination Part, 111...Filter, 112...Background noise level generator, 11
3... Comparator, '+14... Integrator, 115... Comparator, 116... Monostable multi-bi break, 120...
Function generator, 121...monostable multivibrator, 122...
Integrator, 130...Sensor abnormality diagnosis section, 131...Filter. 132...average circuit. +33... Comparator, 134... Comparator, 135... AND gate, 16s... Surging signal, 122S... Surge avoidance signal, 135S... Surge sensor abnormality diagnosis signal. Figure 2 Procedures Amended by: 1287/1987 Kazuo Wakasugi, Commissioner of the Patent Office 1, Indication of the case Patent application Shoyo 7-/J7?77 2, Name of the invention Gas turbine engine control device 3, Amendment Relationship with the case of the person who filed the claim Special claim applicant (Jyy) Nissan Motor Co., Ltd. 1. The scope of claims is amended as per the appendix. 2. The specification is amended as follows. l) 1st line of specification tube 2, 1st line of the same page, 6th line of page 5, 7th line of the same page, 1st/line of the same page, 1st line of the same page , fMA page 1st line, same page 3rd line. 1st line of the same page, 1st line of the same page, 1st line of the same page, 1st line of the same page. The ``compressor'' on line 16 of the same page and line 71 of page 1 is revised to ``pressure 57 machine.'' 7H. , 2) In the first line of the first page, ``Ya fuel flow path'' is corrected to ``YA air flow path''. 3) Correct "Gas Turbine Engine" in the third line of the same line j to "Gas Turbine Engine". Delete "Is the surge sensor/4 included in the surge determination unit/10" on the 1st line of the same page. Replace “IIGL generator” on page 12, line 12 of the same with “BG
Corrected to "L generator". t) Delete [SW compares, field] in lines 1 to 7 of page 13. 7] “Surging lt J” on page 16, line 5 of the same page.
Corrected to ``Surge sensor/6''. r Ngg 'mJ, page 17, line 10 (7)
f r Ngg'J k - Correct. ri) In the second line of page 1, ``the occurrence of can be suppressed'' should be corrected to ``the occurrence of can be constantly suppressed.'' 3. @Figure 7, Figure 3 (5), and Figure 1 ω are corrected as shown in the attached sheet. Attachment 2, Claims 1) In a gas turbine engine control device that performs closed-loop control to match the rotational speed of a gas generator to a predetermined target rotational speed, surge detection means for detecting the occurrence of surging; The gas generator is configured to perform a surge determination step to determine the strength of the generated surging based on the output from the surge detection means, and to avoid surging based on the determination output from the surge determination means. A control device for a gas turbine engine, characterized in that it comprises a correction means for correcting the 11 rotational speed of the engine. 2. The device according to claim 1, wherein the surge determination means It has a comparison means for comparing the output from the means with a predetermined base DB 61, and when it is determined by the one bale comparison means that the force 11 exceeds the reference value, surging occurs toward the correction means. A control device for a gas turbine engine, characterized in that the control device for a gas turbine engine is configured to send a determination output to the effect that a surging The target rotational speed of the gas generator is corrected so that the target rotational speed of the gas generator is rapidly decreased by a predetermined amount when a judgment output indicating that the occurrence of the gas generator is supplied, and then the target rotational speed is gradually increased again. A gas turbine engine control device.

Claims (1)

[Scope of Claims] l) A control device for a gas turbine engine that performs closed-loop control to match the rotational speed of a gas generator to a predetermined target rotational speed, comprising a surge detection means for detecting the occurrence of surging, and a surge detection means for detecting the occurrence of surging; surge determination means for determining the strength of the generated surging based on the output from the detection means;
A gas turbine engine control device comprising: a correction means for correcting a target rotational speed of the gas generator so as to avoid surging based on a determination output from the surge determination means. 2. In the device according to claim 1q4, the surge determining means has a comparing means for comparing the output from the surge detecting means with a predetermined reference value, and the comparing means determines whether the output is equal to the reference value. A control device for a gas turbine engine, characterized in that when it is determined that surging has occurred, a determination output indicating that surging has occurred is sent to the correcting means. 3) In the apparatus according to claim 1 or 2, the correction means adjusts the rotational speed of the gas generator when a determination output indicating that surging has occurred is supplied from the surge determination means. A control device for a gas turbine engine, characterized in that the target rotational speed is corrected so as to quickly decrease it by a predetermined amount and then gradually increase it again.