RU2482024C2 - Method of helicopter power plant control - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: invention relates to aircraft engineering and may be used in helicopter turboprop ACSs. Proposed invention consists in measuring and comparing of rotor rpm of turbo compressors of own and adjacent engines in takeoff mode. In case mismatch between said rpm exceeds preset magnitude, pilot uses "Emergency mode" to up the setting of turbo compressor rotor rpm limiter by preset value defined depending upon engine intake air pressure and temperature. Second electronic controller is used to measure gas temperature in the area of turbo compressor turbine distributors and to compare it with maximum tolerable value. In case gas temperature exceeds tolerable value control action for fuel dispenser is generated to decrease fuel flow rate until measured gas temperature drops below said tolerable value. Electric pressure controller and two independent transducers are used to measure free turbine rotor rpm to compare every measured rpm with maximum tolerable value. In case, at least, one measured rpm exceeds maximum tolerable value, the pilot is warned by signal "engine rotor rpm overshoot" while when two measured rpm exceeds said tolerable value shutdown signal is generated and engine is cut off.

EFFECT: higher reliability of power plant.

1 dwg

Description

The invention relates to the field of aircraft engine manufacturing and can be used in electronic systems (ACS) for automatic control of twin-engine power plants of helicopters.

A known method of controlling the power plant of a helicopter, consisting of two engines working on one rotor, which consists in determining for each engine the magnitude of the mismatch of the frequency of rotation of a free turbine relative to a given one and converting it into a control action (US patent No. 3820323 class. 60-39.28R, 1977).

The disadvantage of this method is its low efficiency.

Closest to this invention in technical essence is a method of controlling a helicopter power plant, consisting of two engines working on one main rotor, which consists in measuring the position of the engine control lever, the pressure and air temperature at the engine inlet, the air pressure behind the compressor own and neighboring engines, the rotor speed of the turbocompressor, the frequency of rotation of the free turbine, using a hydromechanical unit (HP) according to known dependencies form the control its effect on the fuel dispenser in HP and the engine is controlled at start-up, low gas, take-off mode, at throttle response and reset, at power synchronization mode, at engine shutdown (TV3-117 Engine Operation Manual, Motor Sich OJSC ", Zaporozhye, 1986, p.23-27).

The disadvantage of this method of controlling the power plant of a helicopter is the following.

The method does not provide:

- engine protection when operating at elevated gas temperatures in front of the turbine;

- protection of engines from destruction in case of violation of the integrity of the shaft between the free turbine and the gearbox;

- Helicopter protection when turning off one of the engines in flight.

This reduces the reliability of the power plant and the safety of the helicopter.

The aim of the invention is to improve the quality of ACS and, as a result, increase the reliability of the power plant and the safety of the helicopter.

This goal is achieved by the fact that in the method of controlling the power plant of the helicopter, consisting of two engines operating on one main rotor, which consists in measuring the position of the engine control lever, the pressure and temperature of the air at the engine inlet, the air pressure behind its compressor and the neighboring engine, the rotor speed of the turbocompressor, the rotor speed of the free turbine, using a hydromechanical unit (HP) according to known dependencies form a control action on the dosage p of fuel in HP and they control the engine at start-up, low gas, take-off mode, at throttle response and reset, at power synchronization mode, at engine shutdown, in addition, using the first electronic unit (ERE), the rotor speed of the turbocharger of the neighboring engine is measured, compare the rotational speeds of the rotor of the turbocharger of its own and neighboring engines in the take-off mode, when the mismatch of the rotational speeds of the rotor of the turbocompressor of its and neighboring engines is greater than the predetermined value, it is determined divided by calculation and experimentally, according to the pilot's emergency mode signal, the setting of the turbocharger rotor speed limiter in HP is increased in advance by a predetermined value, calculated depending on the temperature and air pressure at the engine inlet, the temperature is measured using a second electronic controller (RT) gases in the zone of the nozzle apparatus of the compressor turbine, compare it with the maximum permissible, with an increase in the measured temperature of the gases above the maximum permissible, a control pressure on the fuel dispenser in HP and reduce fuel consumption until the measured gas temperature drops below the limit, using the ERE two independent sensors measure the rotor speed of the free turbine, compare each measured frequency with the maximum allowed, determined by calculation and experimental method, if at least one measured frequency exceeds the maximum permissible, a signal is generated to the pilot “Exceeding the rotational speed of the rotor of the power turbine of the right (left) engine”, if both measured frequencies are rotated I exceeds the maximum allowable, form a stop signal to the mechanism in HP, with its help the feed of fuel into the combustion chamber (CC) and turn off the engine.

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

A device that implements the method contains a series-connected sensor unit 1 (DB), a first electronic controller 2 (ERE), a hydromechanical controller 3 (HP), which includes a block 4 of electrohydroconverters (EHP), the input of which is connected to the output of the ERE 2, and the outputs are connected to the metering unit 5 and the stop valve 6 (CO) in series, the second electronic controller 7 (RT), the input of which is connected to the OBD 1, and the output to the electric propulsion unit 2, the second OBD 8 connected to the computing device 9 (GR ) in HP 3, the second input of the GR 9 is connected to block 4, and the output to the dispenser 5.

ERD 2 and RT 7 are specialized digital computers, consisting of an input / output device (I / O) and a computer (processor; read-only memory - ROM, with specialized software recorded in it - open source software, operational memory - RAM).

The device operates as follows.

Using DB 8, the position of the engine control lever, the pressure and air temperature at the engine inlet, the air pressure behind the compressor of its own and the neighboring engine, the rotor speed of the turbocompressor rotor, and the rotor speed of the free turbine are measured. Using GR 9 HP 3 according to known dependencies, a control action is formed on the fuel dispenser 5 in HP 3 and the engine is controlled at start-up, “low” gas, take-off mode, pick-up and reset, power synchronization mode, and engine shutdown.

For example, the control of the TV3-117 engine is carried out using the HP-3 unit as follows.

At engine start, fuel is dosed according to the program

Where

RT1 - fuel pressure in the first collector of the COP,

Pk - air pressure behind the engine compressor,

Rn is the air pressure at the engine inlet.

In addition, the HP-3 unit at engine start ensures the starter is switched off by the rotational speed of the turbocharger rotor.

In the “small” gas mode, the fuel is dosed by one of the control loops (to select a loop, minimum selection is provided):

Where

n tk min - the minimum permissible rotor speed of the turbocompressor,

and

Where

G t min - the minimum allowable fuel consumption in the engine COP.

Program setting (3) has two meanings: for terrestrial “small” gas and flight “small” gas. Switching is performed depending on the air pressure at the engine inlet.

In intermediate modes, the fuel is dosed by one of the control loops (to select a loop, minimum selection is provided):

Where

n TC - a given rotational speed of the rotor of the turbocompressor,

α ores - the position of the engine control lever,

Twh. - air temperature at the engine inlet,

and

Where

n st - rotor speed of a free turbine.

In the take-off mode, the limitation of the maximum rotational speed of the turbocompressor rotor is additionally involved in the control of fuel metering:

Where

n tk max - the maximum permissible rotor speed of the turbocompressor

Twh. - air temperature at the engine inlet.

At injectivity, fuel metering is carried out according to the program:

Where

G t an - a given fuel consumption in the engine КС,

Pk - air pressure behind the engine compressor,

n tk is the rotor speed of the turbocompressor.

At the discharge, fuel is dosed according to the program:

Where

G t as - a given fuel consumption in the engine CS,

τ is the time.

Additionally, in a number of helicopter flight modes, the pilot's team synchronizes the power of the engines of the power plant. Synchronization is carried out according to the air pressure behind the compressor (Pk) due to the "connection" of an engine with a smaller Pk to an engine with a large Pk.

The engine is stopped at the command of the pilot due to the cessation of fuel supply to the compressor station using block 4 and KO 6.

Quantitative characteristics of dependencies 1–8 are given in the book “Operation manual for the TVZ-117 engine”, OJSC “Motor Sich”, 3aporozhye, 1986, pp. 40, 87-99.

Additionally, with the help of the first electronic unit, the ЭРД 2 and БД 1 measure the rotational speed of the rotor of the turbocharger of the neighboring engine, in the ERD 2 compare the rotational speeds of the rotor of the turbocharger of its own and neighboring engines in the take-off mode, when the mismatch of the rotational speeds of the rotor of the turbocharger of its own and neighboring engines is greater than the predetermined value, determined by calculation and experimental means, at the pilot’s signal “Emergency mode”, by the command of the electric propulsion 2 increase the setting of the frequency limiter VR using block 4 scheniya turbocharger rotor in GH 3 to 9 HP predetermined value being calculated in dependence on the temperature and air inlet pressure to the engine.

So, for example, for the TVZ-117 engine, the predetermined value of the mismatch of the rotational speeds of the rotor of the turbocharger of its own and neighboring engines is 5%, and the increase in the setting of the limiter (6) of the GR 9 in HP 3 is up to 15% depending on the temperature and air pressure entering the engine.

This provides an opportunity to increase the take-off thrust of the TVZ-117 engine in emergency operation by (15-20)%. For Mi-8 and Ka-50 class helicopters, this is enough to successfully complete the flight when one of the engines is turned off.

Thus, by improving the quality of engine control, the reliability of the power plant and the safety of the helicopter are improved.

Additionally, using the second electronic regulator RT 7 and BD 1, the temperature of the gases in the zone of the nozzle apparatus of the compressor turbine is measured, compared with the maximum allowable temperature; when the measured gas temperature is higher than the maximum allowable temperature, a control effect is formed to reduce fuel consumption in the compressor station. The control action of RT 7 enters the ERD 2, where it is selected to a minimum with the control action of the ERD 2. The selected effect is fed from the ERD 2 to block 4 and then to the dispenser 5. By changing the position of the dispenser 5, reduce fuel consumption in the compressor station until the measured gas temperature does not fall below the limit.

For the TVZ-117 engine, for example, the maximum permissible gas temperature is 750 ° C.

Thus, the engine is protected from overheating of the turbine, which increases the reliability of its operation and ensures the “correct” generation of the gas generator resource.

The use of two relatively simple regulators (ERE and RT) and an almost full-size backup HP regulator on a helicopter engine instead of a single FADEC type regulator allows to save money when equipping and operating a helicopter. So, for example, the total price of the ERD-ZVM, RT-12-6 and NR-3 units for the TVZ-117VM engine is 3.5 times lower than the price of the RED-90A2M unit for the PS-90A2 engine.

In addition, with the help of the electric propulsion system 2, two independent sensors in the database 1 measure the rotor speed of a free turbine rotor, compare each measured frequency with the maximum permissible determined by calculation and experimental methods, if at least one measured frequency exceeds the maximum permissible, a signal is generated for the pilot turbines of the right (left) engine ”, if both measured speeds exceed the maximum permissible, form a signal to the stop mechanism (block 4 and KO 6 in HP 3), with its help They turn on the fuel supply to the compressor station and turn off the engine.

For the TVZ-117 engine, for example, the maximum permissible rotor speed of a free turbine rotor is 118%. Duplication of measuring the rotor speed of a free turbine is necessary to protect against false engine shutdowns.

Thus, the engine is protected from destruction in case of violation of the integrity of the shaft between the free turbine and the gearbox, which increases the reliability of its operation and ensures increased safety of the helicopter.

Claims (1)

The method of controlling the power plant of a helicopter, consisting of two engines operating on one main rotor, which consists in measuring the position of the engine control lever, the pressure and temperature of the air at the engine inlet, the air pressure behind the compressor of its own and neighboring engines, the rotor speed of the turbocharger rotor , the rotational speed of the rotor of a free turbine, using a hydromechanical unit (HP) according to known dependencies form a control action on the fuel dispenser in HP and control for the engine at start, low gas, take-off mode, pick-up and reset, power synchronization mode, engine shutdown, characterized in that the rotor speed of the neighboring engine’s turbocharger is additionally measured using the first electronic unit (ERE), and the rotational speeds are compared the rotor of the turbocharger of its own and neighboring engines in the take-off mode, when the rotational frequencies of the rotor of the turbocompressor of its own and neighboring engines are mismatched, it is greater than the predetermined value determined by experimentally, according to the pilot's emergency mode signal, the setting of the turbocharger rotor speed limiter in HP is increased by a predetermined value, calculated depending on the temperature and air pressure at the engine inlet, the gas temperature in the zone is measured using a second electronic controller (RT) nozzle apparatus of the compressor turbine, compare it with the maximum allowable, with an increase in the measured temperature of the gases above the maximum allowable form a control action on the dispenser top willow in HP and reduce fuel consumption until the measured gas temperature drops below the limit, using the ERE two independent sensors measure the rotor speed of the free turbine, compare each measured frequency with the maximum allowed, determined by calculation and experimental means, if at least one measured frequency exceeds the maximum permissible, they form a signal to the pilot “Exceeding the rotational speed of the rotor of the power turbine of the right (left) engine”, if both measured speeds exceed the limit permissible, they form a signal to the stop mechanism in HP, with it, stop the supply of fuel to the combustion chamber (CS) and turn off the engine.