RU2196240C1 - Method of starting aircraft turbo-jet engine - Google Patents

Abstract

FIELD: methods of starting aircraft turbo-jet engines. SUBSTANCE: proposed method consists in actuating the starter, connecting its shaft to engine rotor and disconnecting starter shaft after developing required rotational speed by rotor. In an emergency in case of failure to start engine in flight, as well as in conducting ground tests, starter shaft is disconnected from engine rotor and starter is shifted to operation in mode of auxiliary power plant. Under standard conditions, cartridge starter is used for starting the engine or for conducting the ground tests. In an emergency, cartridge starter is used in parallel with gas-turbine starter. Cartridge starter is also used in zone of non-guaranteed start of gas-turbine starter. Proposed method makes it possible to start engine practically under any conditions on ground and at any altitude in flight, thus enabling the pilot to orient aircraft to zone of probable ejection. EFFECT: enhanced efficiency and reliability. 1 dwg

Description

 The invention relates to the field of aviation technology, in particular to methods for starting aircraft turbojet engines.

 A known method of starting a turbojet engine of an aircraft, which consists in starting the starter, connecting its shaft to the engine rotor and after the rotor sets a predetermined speed, disconnecting the starter shaft from it, and in an emergency when the engine cannot be started in flight or when the aircraft systems work on the ground in disconnecting the starter shaft from the engine and switching it to work in the auxiliary power plant mode, and under normal conditions for starting the engine or when checking aircraft systems on the ground in achestve starter turbine starter used [1].

 The disadvantage of this method is the limited range of flight altitude at which the engine can be started if it stalls. It is known that with increasing flight altitude, the output power of a gas turbine starter decreases significantly. So, for example, at a flight altitude of more than 7 kilometers, the power of a gas turbine starter is insufficient to twist the engine rotor with signs of stalling, and engine start is not guaranteed. At the same time, ensuring the possibility of such a launch is especially relevant for modern super-maneuverable aircraft.

 The promotion of the engine rotor with a gas turbine starter is also difficult in extreme conditions to start the engine on the ground (high ambient temperature, high altitude conditions, etc.).

 In addition, in a known manner, the drive of the executive units of the aircraft is not always ensured in an emergency, and thus the pilot is not given the opportunity to orient the aircraft into the zone of possible ejection.

 The proposed invention solves the problem of ensuring that the engine starts on the ground under any environmental conditions, including extreme conditions, and in flight with signs of engine stalling at almost any height from the area of possible aircraft flights and ensuring emergency operation of the aircraft's executive units.

 To solve the above problem, in the method of starting a turbojet engine of an aircraft, which consists in starting the starter, connecting its shaft to the engine rotor and after the rotor sets a predetermined speed, disconnecting the starter shaft from it, and in an emergency when the engine cannot be started in flight or when checking the operation of the systems aircraft on the ground in disconnecting the starter shaft from the engine rotor and switching the starter to work in auxiliary power mode, and under normal conditions to start the engine or When testing the operation of the aircraft on the ground is used as a starter turbine starter, in extreme conditions, engine starting and emergency situations as parallel with the starter turbine starter used powder starter, and in an unsecured zone of starting the turbine starter used powder starter.

 The distinguishing features of the proposed method are the use of a powder starter in parallel with the gas-turbine starter for starting the engine in extreme conditions or in emergency situations, and in the zone of the non-guaranteed start of the gas-turbine starter one powder starter. This allows you to start the engine in almost any conditions on the ground and at any height of the zone of possible flights, and also allows the pilot in an emergency if it is not possible to start the engine for some time (approximately 2 minutes) to affect the control surfaces of the aircraft and thereby orient the aircraft in the area of possible bailouts.

 The invention is illustrated in the drawing diagram of the engine starting system of the aircraft.

 The proposed method is implemented by the aircraft turbojet engine start system, which contains gas turbine and powder (mainly multiply charged) starters 1 and 2 installed parallel to each other. Both starters 1 and 2 are connected by their shafts to the power supply nodes of the aircraft systems: with the generator 3 and the plunger pump 4. The starter 1, generator 3 and pump 4 provide power to the aircraft systems on the ground for testing purposes, operating in the auxiliary power plant mode. For operation in auxiliary power plant mode, the above units are mechanically disconnected from the motor shaft 5 by means of one controlled clutch 6 or several couplings. Both starters 1 and 2 are connected to the engine shaft via freewheels (not shown).

 The method of starting a turbojet engine of the aircraft is as follows.

 To ensure verification of aircraft systems without the use of ground-based means, as well as to ensure comfortable conditions in the cockpit under extreme temperature conditions on combat duty, the auxiliary power unit mode is activated, for which a gas turbine starter 1 is launched, the torque from which is transmitted through the overrunning clutch of the starter 1 and a set of gears to consumers, while the clutch 6 is open. The gas turbine starter 1 enters into steady state and provides the drive of aircraft units and air supply to the air conditioning system for a predetermined time.

 To start the engine on the ground, the gas turbine starter is put into start mode. Upon reaching a certain speed of the engine shaft from the gas turbine starter, the starter is disconnected and the further drive of the aircraft units is carried out from the engine. Under extreme conditions, to start the engine on the ground (high ambient temperature, high altitude conditions), a powder starter is launched in parallel with the start of the gas turbine starter, the additional torque from which is transmitted to the engine rotor, thereby improving the starting conditions.

 The engine is started in flight after it has stalled when the ignition is turned on and the fuel is supplied in the autorotation range of the engine rotor and flight altitude sufficient to start the engine. At lower autorotation revolutions, that is, at lower instrument speeds, up to a certain flight altitude (up to 7 km), the engine rotor is twisted by a gas turbine starter 1, which is started by a command generated in accordance with the instrument speed and signs of engine stalling. When this clutch 6 is closed and the torque from the gas turbine starter 1 is transmitted to the shaft of the engine 5. After starting the engine, the starter 1 is turned off.

 To reduce the start time of the engine, the twist of its rotor in flight in the zone of guaranteed start of the gas turbine starter is performed in parallel with the gas turbine and powder starter.

 In the field of non-guaranteed launch of a gas turbine starter (at an altitude of more than 7 km), the engine rotor is twisted by starting a powder starter.

 In a situation where it is impossible to start the engine in flight (jamming, fire, etc.), to ensure the conditions for pilot ejection, as well as to take the aircraft to a safe fall zone, open clutch 6 and start the long-running (2-3 minutes) step of the powder starter 2, the torque from which through an overrunning clutch and gears is transmitted to the shafts of the generator 3 and pump 4, providing partial power to the hydraulic and electrical systems of the aircraft for 2-3 minutes. If an emergency occurred in the area of the possible operation of the gas turbine starter, then in parallel with the powder starter 2, the gas turbine starter 1 can be switched on.

 The proposed method allows to expand the starting zone of the engine and provides emergency operation of the executive units of the aircraft.

Sourse of information
US patent 4461143 A, IPC F 02 C 7/26, 1984

Claims (1)

 A method of starting an aircraft turbojet engine, which consists in starting the starter, connecting its shaft to the engine rotor and after the rotor sets a predetermined speed, disconnecting the starter shaft from it, and in an emergency when the engine cannot be started in flight or when the aircraft systems work on the ground in shutdown the starter shaft from the engine rotor and switching the starter to work in the auxiliary power plant mode, and under normal conditions to start the engine or when checking the operation of aircraft systems and earth is used as a starter turbine starter, characterized in that under extreme conditions of engine starting and emergency as a starter in parallel with the turbine starter used powder starter, and in an unsecured zone of starting the turbine starter used powder starter.