RU2306446C1 - Method of control of aircraft power plant - Google Patents

Abstract

FIELD: methods of control of aircraft power plants consisting of two gas-turbine engines in case of loss of thrust by one of them.

SUBSTANCE: proposed method of control of aircraft power plant includes measurement of parameters of thrust of two engines, comparison of these parameters with preset magnitudes required for starting the increased thrust mode, measurement of engine control lever position and comparison of them with preset magnitudes corresponding to takeoff mode of aircraft; in case of failure of one of engines, increased thrust mode of other engine is started. Proposed method includes also additional measurement of aircraft air speed V_a. Which is compared with preset speed and signals I_sl. "slats not retracted" and I_p.b. "parking brake switched off". Increased thrust of intact engine is settled at V_a.> and availability of signals I_sl. and I_p.b.

EFFECT: enhanced safety of flight due to avoidance of prohibitive settling of increased thrust mode at takeoff and ascent of aircraft.

3 cl, 1 dwg

Description

The invention relates to methods for controlling a power plant of an aircraft, consisting of two gas turbine engines (GTE), in case of failure or partial loss of traction of one of the engines.

A known method of controlling the power plants of aircraft, which to ensure trouble-free operation, provide for an automatic increase in the thrust of a gas turbine engine at certain stages of flight [British Patent No. 2262623, F02C 9/26, 1993].

An increase in the thrust of a gas turbine engine is provided for in two special cases - during take-off from an airfield in high altitude conditions and during air patrolling at turns without reducing the flight altitude. The increase in thrust is achieved by increasing fuel consumption in the combustion chamber with a simultaneous increase in the limiting (reference) values of the adjustable engine parameters. Since there is no direct activation of the thrust increase program, the pilot determines in advance the possible need to increase thrust by moving the engine control lever to the appropriate position (the initial condition for starting the program). At the same time, to enable the increased thrust mode (RPT) during take-off in high altitude conditions, two conditions must be met:

- the barometric altitude of the airfield is in the range of 5000 ... 10000 feet (from ~ 1500 m to 3000 m above sea level);

- the airspeed of the aircraft is lower than the stall speed.

As the input parameters of the system of known methods are used:

- the position of the engine control lever, which displays the need to turn on the RPT;

- ambient air pressure, which determines the barometric altitude of the airfield;

- the temperature of the turbine blades, which most accurately characterizes the thermal state of the turbine and is one of the main adjustable parameters of the turbine engine;

- airspeed of the aircraft.

Measurement of input information, comparison of the airspeed of the aircraft with the minimum acceptable value, the formation of the control action to increase traction is implemented in the digital electronic control unit of the gas turbine engine.

The disadvantages of these methods are as follows.

During continuous operation of the aircraft in high altitude conditions, before each take-off, it is necessary to determine the need to activate the increased thrust mode, which makes possible errors and risks.

So, without moving the engine control lever (ORE) to the position of boosting the thrust, and in case of complete or partial loss of thrust of one of the engines (for example, after the birds got into the air intake, regular or false positives of the protective and emergency systems), the power plant control system in a twin-engine option may not provide the required dynamics of climb.

In case the pilot, guided by safety considerations, during take-off in high altitude conditions will constantly shift the throttle to the thrust boost position (regardless of loading, aerodrome features), then the take-off propulsion will be constantly switched on during take-off until the airspeed of the aircraft reaches a safe value. It is known that each inclusion of RPT leads to a significant increase in thermogasdynamic parameters and, as a consequence, to an accelerated development of the engine resource. With the systematic operation of the mode, this leads to early removal of the engine from the wing, which is economically inexpedient. In addition, if the RPT is turned on for too long or frequently at high air temperatures, engine overheating and mechanical destruction of the turbine blades are also possible.

In certain conditions, for example, with false information from the airspeed sensor or its failure, false activation of the increased traction mode is possible.

The situation may become potentially dangerous when taking off from an aerodrome located at an altitude slightly (2 ... 5%) less than what is necessary by the condition for the inclusion of the algorithm. For example, in the presence of the aforementioned failures and adverse operational factors, especially for a twin-engine version of the power plant.

There is also known a method for controlling a gas turbine engine, according to which, after detecting a malfunction or damage to the engine caused by the entry of birds or an enemy ballistic object into the engine, the engine system implements measures of resource allocation to maintain (restore) the existing thrust of the faulty engine by increasing the rotation of the turbine engine rotor [Patent EPO No. 1281846, F02C 9/00, 2003]. However, in the event of a malfunction of one of the aircraft’s engines during take-off (for example, a breakdown and damage to the turbine rotor blades), an increase in the limit (setpoint) values of the adjustable parameters and the operating mode of the faulty engine can lead to its final breakdown and non-localized failure. Therefore, in these and similar cases, important factors are determining the ability of the faulty engine to reach increased traction, which is extremely difficult to implement using known methods, because visual monitoring of the entire gas-air path of the engine is necessary.

As a prototype, the control method of the aircraft’s power plant was chosen, according to which, in the event of engine failure, the required engine thrust loss is determined and the serviceable engine mode is increased, regardless of the height of the airfield ["Design and operation of power plants of IL-96-300 aircraft , TU-204, IL-114 ", Moscow," Transport ", 1993, p.19].

According to the known method, a GTE failure (loss of thrust) is determined by a decrease in the fan speed (n _in ) and its first derivative (dn _in / dt) below the specified values, and an automatic increase in the serviceable engine mode is performed while the throttle is in takeoff mode and there is a signal "Aircraft parking brake is off", characterizing the movement of the aircraft.

The disadvantages of the prototype include the negative consequences of the inclusion of RPT, which consists in the accelerated development of the gas turbine engine resource in cases when it is not required by the flight conditions, for example, at the beginning of the take-off run or during climb as applied to the prototype. In addition, the resulting multi-thrust of the engines can lead to an undesirable turning moment of the forces acting on the aircraft.

The technical problem solved by the invention is to increase flight safety by eliminating unacceptable inclusions of the increased thrust mode in conditions of airplane takeoff and climb.

The essence of the invention lies in the fact that in a method of controlling a power plant of an aircraft, comprising measuring the thrust parameters of two engines of a power plant, comparing their values with a predetermined value necessary to activate the increased thrust mode, measuring the positions of the engine control levers, comparing them with predetermined values corresponding to according to the invention, the take-off mode of the aircraft, in the event of a malfunction or failure of one engine, the inclusion of increased thrust of another engine zdushnuyu aircraft velocity V _c, comparing V _c to a predetermined value V _c ^ass produce signals I _P "slats are not cleaned" and I _T "park brake off" and increased thrust mode serviceable engine include at V _c> V _c ^ass and the presence of signals _IP and _IT .

As a given airspeed of the aircraft V _c ^ass use the speed of decision-making about take-off V _vzl . The speed of decision-making on take-off characterizes the take-off speed of the aircraft at which a safe termination and safe continuation of take-off is possible [Flight Safety. Edited by Doctor of Technical Sciences, Professor R.V. Sakach, Moscow, "Transport", 1989, p. 94].

As an engine traction parameter, various motor parameters can be used that most accurately reflect the traction characteristics of this type of engine. For example, for an engine with a large bypass ratio (> 4), this may be the fan speed (n _in ). To increase the speed of traction diagnostics, such a parameter can serve as the total signal of the fan speed (n _in ) and its first derivative (dn _in / dt) in the form (n _in + С · dn _in / dt), where the coefficient C depends on the dynamic properties of the rotor fan.

The presence of the signal I _T "slats not removed" indicates the presence of wing mechanization in the take-off configuration. At the end of the take-off of the aircraft, the wing mechanization transitions from the take-off configuration to the flight configuration, while the “slats are not removed” signal is removed, which further excludes the inclusion of increased thrust during flight.

The signal I _P "parking brake is released" comes from the signaling device after the crew turns off the parking brake before the aircraft takes off on the runway and is not removed almost until the end of the flight.

The removal of the increased thrust mode is carried out only by the pilot by switching the throttle to a lower mode, i.e. provided α _ores <α _ores ^back .

The drawing shows a structural diagram of a device that implements the inventive method.

The control of engines 1 and 2 is provided by digital control units 3 and 4, respectively. On engines 1 and 2, sensors 5 and 6 of the position of the engine control lever (ORE) are installed, as well as sensors 7 and 8 of the fan speed. Executive bodies 9 and 10 provide an increase in traction characteristics of engines 1 and 2, respectively. The output signals of the sensors 7 and 8 of both engines 1 and 2 are simultaneously supplied to the control units 3 and 4.

Digital control units 3 and 4 contain similar units, the signals to which are received from sensors 8 and 6, as well as sensors 5 and 7, respectively.

In block 11, the measured value of α _ORE is compared with a given value of α _ORE ^ass , corresponding to the take-off mode of the aircraft. When α _ORE > α _ORE ^back at the output of block 11, the first logical signal I ₁ = 1 is formed.

In the differentiator 12, the first derivative of the fan speed (dn _in / dt) of the neighboring engine is calculated when a signal is received from the sensors 7 and 8.

The adder 13 performs algebraic summation of the signals coming from the sensors 8, 12 and 7, 12, proportional to the fan speed (n _in ) and its first derivative (dn _in / dt) of the neighboring engine.

In the comparison unit 14, the output signal from the adder 13 is compared with a predetermined value n _{in the} ^ass , which is necessary to enable increased traction. If n _in <n _{in the} ^ass , then the second logical signal I ₂ = 1 is formed at the output of the comparison unit 14.

The sensor 16 captures the airspeed of the aircraft and sends a signal to the sensor-annunciator 17, in which the values of V _c are compared with V _c ^ass and when V _c > V _c ^{ass, a} discrete signal “decision speed” is received at the input of block 15 (I ₃ = 1).

Logic device 15 is made with 5 inputs and operates according to the "AND" scheme. In addition to the signals I ₁ and the signal I ₂ coming from a neighboring engine to the input of the logic device 15 of each digital control unit 3 and 4, depending on the stage of the flight, discrete signals from sensor-signaling devices 17, 18 and 19, which are common to two engines, are received.

The sensor-detector 18 generates a signal "parking brake is off" (I _T = 1), and the sensor-detector 19 - a signal "slats not removed" (I _P = 1). Discrete signals I _P = 1, I _T = 1 and I ₃ = 1 are received at the input of logic block 15. In general, discrete signals can come from the corresponding aircraft systems in the form of a digital code.

Block 15 at the output generates a control signal to the actuators 9 and 10 of engines 1 and 2, respectively.

The device operates as follows.

At the executive start, before the aircraft takes off on the runway, when V _c = 0, the engines operate at idle speed. At the input of each digital control unit 3 and 4, a discrete signal “slats are not removed” (I _P = 1), which indicates the wing configuration necessary for take-off, is received normally from the sensor-detector 19.

After moving both of the throttle to take-off mode, a signal I ₁ = 1 is formed at the output of the comparison unit 11.

After increasing the thrust of engines 1 and 2, the crew turns off the parking brake of the aircraft, the aircraft starts to take off, while sensor 18 generates a signal I _T = 1, which is fed to the input of logic block 15.

When the aircraft airspeed V _{c is} greater than the predetermined take-off speed V _c ^ass , the signal I ₃ = 1 is generated at the output of block 17, which is fed to the input of logic block 15.

In the event of a failure or partial loss of engine thrust, for example 1, which is characterized by a decrease in the fan speed n _in and its first derivative (dn _in / dt) below the specified and corresponding need to turn on the increased thrust mode, at the output of the comparison unit 14 of the digital control unit 4 of the adjacent engine 2 is formed by a logical signal I ₂ = 1, fed to the input of block 15 of the same control unit 4.

When signals are received, I ₁ = 1 (throttle in Takeoff mode), I ₂ = 1 (failure of another engine mode is below acceptable), I ₃ = 1 (“decision speed”), I _T = 1 (“airplane parking brake” is turned off ") and I _П = 1 (" slats are not removed ") to the inputs of the logic block 15 operating according to the" I "circuit, the output of block 15 generates a logical signal I ₄ = 1 to turn on the increased traction mode, which arrives at the executive body 10 in order to increase the traction characteristics of a working engine 2.

In the event of a malfunction of engine 2, the signal I ₄ = 1 for switching on the increased traction mode is supplied to the executive body 9, which increases the traction characteristics of a working engine 1.

A device that implements the claimed method was tested by bench and flight tests on a TU-214 aircraft with PS-90A engines, including when simulating various types of failures. It was found that the device reliably and with a given speed provided the formation of increased traction.

Claims (3)

1. The method of controlling the aircraft power plant, including measuring the thrust parameters of two engines of the power plant, comparing their values with a predetermined value necessary to activate the high thrust mode, measuring the positions of the engine control levers, comparing them with the set values corresponding to the takeoff mode of the aircraft, in case of malfunction or failure of one engine, the inclusion of increased thrust of another engine, characterized in that it additionally measure the airspeed of the aircraft V _c , compare V _c with set value V _c ^back , form a signal I _p "slats are not removed" and I _t "parking brake is applied", and the increased thrust mode of a working engine is turned on at V _c > V _c ^back and there are signals I _p and I _t 2. The method of controlling the aircraft power plant according to claim 1, where as the given airspeed of the aircraft V _c ^ass , the decision-making speed of take-off V take-off is _used . 3. The method of controlling the aircraft power plant according to claim 1, where as a parameter of engine thrust, use the total signal of the fan speed n _in and its first derivative dn _in / dt in the form n _in + C · dn _in / dt, where C is the weight a coefficient depending on the dynamic properties of the rotor of the engine fan.