A twin-engine helicopter over-speed protection system and method

Abstract

The present invention belongs to the technical field of engine control, and particularly relates to an over-speed protection system and method for a twin-engine helicopter. It consists of two relatively independent subsystems on the left and right. Considering reliability, each system is composed of two speed sensors, two speed monitoring modules, a voltage relay, a bistable voltage relay, a circuit breaker, an over-speed indicator light, a fuel cut-off valve, a reset switch, and a test switch. When the engine of a twin-engine configuration helicopter over-speeds, it automatically shuts down the engine to reduce the damage suffered by the engine.

Description

Technical Field

[0001] The present invention belongs to the technical field of engine control, and particularly relates to a dual-engine helicopter over-speed protection system and method. Background Art

[0002] For an aeroengine, the rotational speed is a very important parameter. During operation, the pilot judges whether the engine is operating within the rated rotational speed range by reading the engine rotational speed to ensure the safe operation of the engine. Once the aeroengine undergoes over-speed, if not disposed of in time, the engine will be damaged at least, and a flight disaster will occur at worst. Thus, it can be seen that the over-speed protection control system is an important safety protection measure for the aeroengine to operate within a safe range, and it must require high safety and reliability.

[0003] In the utility model CN205064101U, the over-speed protection system of a certain engine measures the rotational speed of the free turbine and transmits the measured signal to the control device to determine whether the engine is over-speeding. Suppose the reliability of the engine over-speed protection system is not high, a fault occurs, and it fails to operate effectively to play a protective role, or an abnormal in-air shutdown may be caused thereby, bringing safety risks to the flight. Summary of the Invention

[0004] The object of the present invention is to automatically implement engine shutdown when the engine of a dual-engine configuration helicopter undergoes over-speed, reducing the damage suffered by the engine. The specific functions are as follows: First, dual-engine over-speed protection interlock. When any one engine undergoes over-speed, the over-speed protection function of the other engine is turned off, and at this time, this engine is allowed to operate at over-speed. Second, the starting function of the over-sped engine is disabled. Once the engine undergoes over-speed, the starting program for this engine is automatically prohibited to avoid secondary damage to the engine. Third, over-speed manual reset function. When the engine undergoes over-speed, continuous over-speed warnings are given, and a manual reset operation must be performed to restore the engine control and indication to the normal working state to ensure the confirmation of the maintenance work on the engine after over-speed.

[0005] The technical solution of the present invention:

[0006] The dual-engine helicopter over-speed protection system described in the present invention consists of two relatively independent subsystems on the left and right. Since the principles of the two systems on the left and right are the same, the left system will be used as an example for description.

[0007] For reliability considerations, each system consists of two rotational speed sensors, two rotational speed monitoring modules, a voltage relay, a bistable voltage relay, a circuit breaker, an over-speed indicator light, a fuel cut-off valve, a reset switch, and a test switch.

[0008] Two of the speed sensors detect the engine speed and are connected to the corresponding speed monitoring modules respectively. The speed sensor 2 is connected to the speed monitoring module 3 to provide the speed signal to the speed monitoring module 3. When the engine enters the threshold set by the over-speed protection, the speed monitoring module 3 control circuit is turned on, and the control signal is connected to the positive end of the coil of the relay 5 of the left system through one contact in the bistable relay 26 of the right system.

[0009] The speed sensor 1 is connected to the speed monitoring module 4 and is used to provide the speed signal to the speed monitoring module 4. When the engine enters another threshold set by the over-speed protection, the speed monitoring module 4 control circuit is turned on, and the control signal is directly connected to the negative end of the coil of the relay 5 of the left system.

[0010] When overspeed occurs, the positive and negative terminals of relay 5 are connected at the same time, relay 5 operates, and the positive control signal is connected to the positive terminal of the overspeed protection coil of bistable relay 6 through one contact of relay 5, and the overspeed protection is started. The current drives the oil cut-off valve 8 through the overspeed protection circuit breaker 9 and the contact of bistable relay 6 to work, cut off the fuel supply of the engine, and interrupt the operation of the engine. At the same time, the signal is connected to the positive terminal of the overspeed indicator light 7 to light it up.

[0011] After exiting the overspeed state, since the bistable relay 6 remains in the overspeed protection on state, after the ground staff confirms the engine status, the overspeed protection state is released by pressing the reset switch 10. When the reset switch is pressed, the current is connected to the positive end of the overspeed protection release coil of the bistable relay 6 through the circuit breaker 9 and the reset switch 10, so that the system returns to the normal monitoring state. At this time, the engine releases the overspeed protection and the overspeed indicator light 7 goes out.

[0012] In addition, during normal operation, since the control ground signal of the starting system is connected through one contact of the bistable relay 6, the starting system can work normally at this time. When the left system overturns, the contacts of the bistable relay 6 are activated, the control ground signal of the starting system is disconnected, the starting system fails, and no longer responds to the driver's starting command.

[0013] The working principle and composition of the right system are the same as those of the left system.

[0014] In the above process, since the control signal of the positive end of the coil of the relay 5 of the left system is connected through one contact in the bistable relay 26 of the right system, when the right system is in the over-rotation protection state, the over-rotation protection control circuit of the left system will be cut off. Similarly, when the left system is in the over-rotation protection state, the over-rotation protection control circuit of the right system will be cut off, thereby achieving the purpose of interlocking the left and right systems.

[0015] Compared with the prior art, the advantages of the present invention are as follows: First, the engine start disabling function after over-speed. Once the engine experiences over-speed, the start procedure for this engine is automatically prohibited to protect the engine from secondary damage. Second, the over-speed manual reset function. When the engine over-speeds, continuous over-speed warnings are given, and a manual reset operation must be performed to restore the engine control and indication to the normal working state to ensure the confirmation of the engine maintenance work after over-speed. Through the above functions, the safety and maintainability of the over-speed protection system are significantly improved. Brief Description of the Drawings

[0016] Figure 1 It is a schematic structural diagram of an over-speed protection system for a twin-engine helicopter provided by an embodiment of the present invention;

[0017] 1 First left speed sensor 2 Second left speed sensor 3 First left speed monitoring module 4 Second left speed monitoring module 5 Left relay 6 Left bistable relay 7 Left over-speed indicator light 8 Left fuel cut-off valve 9 Left circuit breaker 10 Left reset switch 11 Left test switch 21 First right speed sensor 22 Second right speed sensor 23 First right speed monitoring module 24 Second right speed monitoring module 25 Right relay 26 Right bistable relay 27 Right over-speed indicator light 28 Right fuel cut-off valve 29 Right circuit breaker 30 Right reset switch 31 Right test switch. Detailed Embodiment

[0018] The technical solution of the present invention will be described in detail below with reference to the drawings.

[0019] In a certain type of Z-9 helicopter, the above-mentioned over-speed protection system for a twin-engine helicopter is adopted. As Figure 1 shown, specifically, it consists of two relatively independent subsystems on the left and right. Since the principles of the left and right systems are the same, the left system will be taken as an example for description. The left system consists of two speed sensors, a circuit breaker, an over-speed indicator light, a fuel cut-off valve, and an over-speed control unit. Among them, the over-speed control unit incorporates two speed monitoring modules, a voltage relay, a bistable voltage relay, a reset switch, and a test switch.

[0020] Among them, the two speed sensors detect the engine speed and are respectively connected to the over-speed control unit. When the engine reaches the threshold set for over-speed protection, the control signal is connected to the positive end of the coil of the relay 5 in the left system through one of the contacts in the bistable relay 26 of the right system.

[0021] The speed sensor 1 is connected to the speed monitoring module 4 in the over-speed control unit and is used to provide the speed signal to the speed monitoring module 4. When the engine reaches another threshold set for over-speed protection, the control circuit of the speed monitoring module 4 is turned on, and the control signal is directly connected to the negative end of the coil of the relay 5 in the left system.

[0022] When overspeed occurs, the positive and negative terminals of relay 5 are connected at the same time, relay 5 operates, and the positive control signal is connected to the positive terminal of the overspeed protection coil of bistable relay 6 through one contact of relay 5, and the overspeed protection is started. The current drives the oil cut-off valve 8 through the overspeed protection circuit breaker 9 and the contact of bistable relay 6 to work, cut off the fuel supply of the engine, and interrupt the operation of the engine. At the same time, the signal is connected to the positive terminal of the overspeed indicator light 7 to light it up.

[0023] After exiting the overspeed state, since the bistable relay 6 remains in the overspeed protection on state, after the ground staff confirms the engine status, the overspeed protection state is released by pressing the reset switch 10. When the reset switch is pressed, the current is connected to the positive end of the overspeed protection release coil of the bistable relay 6 through the circuit breaker 9 and the reset switch 10, so that the system returns to the normal monitoring state. At this time, the engine releases the overspeed protection and the overspeed indicator light 7 goes out.

[0024] In addition, during normal operation, since the control ground signal of the starting system is connected through one contact of the bistable relay 6, the starting system can work normally at this time. When the left system overturns, the contacts of the bistable relay 6 are activated, the control ground signal of the starting system is disconnected, the starting system fails, and no longer responds to the driver's starting command.

[0025] The working principle and composition of the right system are the same as those of the left system.

[0026] In the above process, since the control signal of the positive end of the coil of the relay 5 of the left system is connected through one contact in the bistable relay 26 of the right system, when the right system is in the over-rotation protection state, the over-rotation protection control circuit of the left system will be cut off. Similarly, when the left system is in the over-rotation protection state, the over-rotation protection control circuit of the right system will be cut off, thereby achieving the purpose of interlocking the left and right systems.

[0027] The above examples have been tested and verified in use, and are capable of achieving the predetermined over-rotation protection function. Although the present invention has been described with reference to the above embodiments, it is obvious that this embodiment is only for illustrative purposes and should not be regarded as an example to limit the scope of protection of the present invention.

[0028] Compared with the prior art, the present invention is applicable to aircraft with twin engines. On the basis of overspeed protection, it realizes: 1. Twin engine overspeed protection interlocking. When any engine overspeeds, the overspeed protection function of the other engine is turned off, and the overspeed protection function of the other engine is allowed to be used. 2. Engine starting function after overspeeding

[0029] Disabled. Once the engine experiences an overspeed, the start-up procedure for this engine is automatically prohibited to prevent secondary damage to the engine. Third, the overspeed manual reset function. When the engine overspeed occurs, continuous overspeed warnings are given. A manual reset operation must be performed to restore the engine control and indication to the normal working state to ensure the confirmation of the engine maintenance work after overspeed.

[0030] Compared with the prior art, the advantages of the present invention are as follows:

[0031] First, the engine start-up disabling function after overspeed. Once the engine overspeed occurs, the start-up procedure for this engine is automatically prohibited to protect the engine from secondary damage. Second, the overspeed manual reset function. When

[0032] the engine overspeed occurs, continuous overspeed warnings are given. A manual reset operation must be performed to restore the engine control and indication to the normal working state to ensure the confirmation of the engine maintenance work after overspeed.

[0033] Through the above functions, the safety and maintainability of the overspeed protection system are significantly improved.

Claims

1. A dual-engine helicopter over-speed protection system, characterized in that, The system is composed of two relatively independent left and right systems, and the left and right systems have the same principles; The left system is composed of a first left speed sensor (1), a second left speed sensor (2), a first left speed monitoring module (3), a second left speed monitoring module (4), a left relay (5), a left bistable relay (6), a left circuit breaker (9), a left overspeed indicator light (7), a left oil cut-off valve (8), a left reset switch (10), and a left test switch (11); The second left speed sensor (2) is connected to the first left speed monitoring module (3); when the engine enters the threshold value set for overspeed protection, the control circuit of the first left speed monitoring module (3) is turned on, and the control signal is connected to the positive end of the coil of the left relay (5) of the left system through one contact in the right bistable relay (26) of the right system; The first left speed sensor (1) is connected to the second left speed monitoring module (4). When the engine enters another threshold value set for overspeed protection, the second left speed monitoring module (4) controls the circuit to be turned on, and the control signal is directly connected to the negative end of the coil of the left relay (5) of the left system.

2. A twin-engine helicopter overspeed protection system according to claim 1, characterized in that: When overspeed occurs, the positive and negative terminals of the left relay (5) are connected simultaneously, the left relay (5) is activated, and the positive control signal is connected to the positive terminal of the overspeed protection coil of the left bistable relay (6) through one contact of the left relay (5), the overspeed protection is started, and the current drives the left oil cut-off valve (8) to work through the overspeed protection left circuit breaker (9) and the contact of the left bistable relay (6), disconnecting the fuel supply to the engine and interrupting the operation of the engine; and the positive control signal is connected to the positive terminal of the overspeed indicator light (7) to light it up.

3. A twin-engine helicopter overspeed protection system according to claim 2, characterized in that: After exiting the overspeed state, since the left bistable relay (6) remains in the overspeed protection on state, after the ground crew confirms the engine state, the overspeed protection state is released by pressing the left reset switch (10). When the left reset switch is pressed, the current is connected to the positive end of the overspeed protection release coil of the left bistable relay (6) through the left circuit breaker (9) and the left reset switch (10), so that the system returns to the normal monitoring state. At this time, the engine overspeed protection is released, and the overspeed indicator light (7) is extinguished.

4. A twin-engine helicopter overspeed protection system according to claim 1, characterized in that: During normal operation, since the control ground signal of the starting system is connected through one contact of the left bistable relay (6), the starting system can operate normally. When the left system over-rotates, the contact of the left bistable relay (6) operates, the control ground signal of the starting system is disconnected, and the starting system fails and no longer responds to the driver's starting command.

5. The twin-engine helicopter overspeed protection system according to claim 1, characterized in that: Since the control signal of the positive end of the coil of the left relay (5) of the control signal left system is connected through a contact in the right bistable relay (26) of the right system, when the right system is in the over-rotation protection state, the over-rotation protection control circuit of the left system will be cut off, and when the left system is in the over-rotation protection state, the over-rotation protection control circuit of the right system will be cut off, thereby realizing the interlocking of the left and right systems.

6. A method for over-speed protection of a twin-engine helicopter, characterized in that, The method is applied to the system according to any one of claims 1 to 5, and the method comprises: When overspeed occurs, the positive and negative terminals of the left relay (5) are connected simultaneously, the left relay (5) is activated, and the positive control signal is connected to the positive terminal of the overspeed protection coil of the left bistable relay (6) through one contact of the left relay (5), the overspeed protection is started, and the current drives the left oil cut-off valve (8) to work through the overspeed protection left circuit breaker (9) and the contact of the left bistable relay (6), disconnecting the fuel supply to the engine and interrupting the operation of the engine; and the positive control signal is connected to the positive terminal of the overspeed indicator light (7) to light it up.

7. A twin-engine helicopter overspeed protection method according to claim 6, characterized in that: After exiting the overspeed state, since the left bistable relay (6) remains in the overspeed protection on state, after the ground crew confirms the engine state, the overspeed protection state is released by pressing the left reset switch (10). When the left reset switch is pressed, the current is connected to the positive end of the overspeed protection release coil of the left bistable relay (6) through the left circuit breaker (9) and the left reset switch (10), so that the system returns to the normal monitoring state. At this time, the engine overspeed protection is released, and the overspeed indicator light (7) is extinguished.

8. A twin-engine helicopter overspeed protection method according to claim 7, characterized in that: During normal operation, since the control ground signal of the starting system is connected through one contact of the left bistable relay (6), the starting system can operate normally. When the left system over-rotates, the contact of the left bistable relay (6) operates, the control ground signal of the starting system is disconnected, and the starting system fails and no longer responds to the driver's starting command.

9. A twin-engine helicopter overspeed protection method according to claim 6, characterized in that: Since the control signal of the positive end of the coil of the left relay (5) of the control signal left system is connected through a contact in the right bistable relay (26) of the right system, when the right system is in the over-rotation protection state, the over-rotation protection control circuit of the left system will be cut off, and when the left system is in the over-rotation protection state, the over-rotation protection control circuit of the right system will be cut off, thereby realizing the interlocking of the left and right systems.

Images